--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#ifndef _UAPI__LINUX_BPF_H__
+#define _UAPI__LINUX_BPF_H__
+
+#include <linux/types.h>
+#include <linux/bpf_common.h>
+
+/* Extended instruction set based on top of classic BPF */
+
+/* instruction classes */
+#define BPF_JMP32 0x06 /* jmp mode in word width */
+#define BPF_ALU64 0x07 /* alu mode in double word width */
+
+/* ld/ldx fields */
+#define BPF_DW 0x18 /* double word (64-bit) */
+#define BPF_XADD 0xc0 /* exclusive add */
+
+/* alu/jmp fields */
+#define BPF_MOV 0xb0 /* mov reg to reg */
+#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
+
+/* change endianness of a register */
+#define BPF_END 0xd0 /* flags for endianness conversion: */
+#define BPF_TO_LE 0x00 /* convert to little-endian */
+#define BPF_TO_BE 0x08 /* convert to big-endian */
+#define BPF_FROM_LE BPF_TO_LE
+#define BPF_FROM_BE BPF_TO_BE
+
+/* jmp encodings */
+#define BPF_JNE 0x50 /* jump != */
+#define BPF_JLT 0xa0 /* LT is unsigned, '<' */
+#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
+#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
+#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
+#define BPF_JSLT 0xc0 /* SLT is signed, '<' */
+#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
+#define BPF_CALL 0x80 /* function call */
+#define BPF_EXIT 0x90 /* function return */
+
+/* Register numbers */
+enum {
+ BPF_REG_0 = 0,
+ BPF_REG_1,
+ BPF_REG_2,
+ BPF_REG_3,
+ BPF_REG_4,
+ BPF_REG_5,
+ BPF_REG_6,
+ BPF_REG_7,
+ BPF_REG_8,
+ BPF_REG_9,
+ BPF_REG_10,
+ __MAX_BPF_REG,
+};
+
+/* BPF has 10 general purpose 64-bit registers and stack frame. */
+#define MAX_BPF_REG __MAX_BPF_REG
+
+struct bpf_insn {
+ __u8 code; /* opcode */
+ __u8 dst_reg:4; /* dest register */
+ __u8 src_reg:4; /* source register */
+ __s16 off; /* signed offset */
+ __s32 imm; /* signed immediate constant */
+};
+
+/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
+struct bpf_lpm_trie_key {
+ __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
+ __u8 data[0]; /* Arbitrary size */
+};
+
+struct bpf_cgroup_storage_key {
+ __u64 cgroup_inode_id; /* cgroup inode id */
+ __u32 attach_type; /* program attach type */
+};
+
+union bpf_iter_link_info {
+ struct {
+ __u32 map_fd;
+ } map;
+};
+
+/* BPF syscall commands, see bpf(2) man-page for details. */
+enum bpf_cmd {
+ BPF_MAP_CREATE,
+ BPF_MAP_LOOKUP_ELEM,
+ BPF_MAP_UPDATE_ELEM,
+ BPF_MAP_DELETE_ELEM,
+ BPF_MAP_GET_NEXT_KEY,
+ BPF_PROG_LOAD,
+ BPF_OBJ_PIN,
+ BPF_OBJ_GET,
+ BPF_PROG_ATTACH,
+ BPF_PROG_DETACH,
+ BPF_PROG_TEST_RUN,
+ BPF_PROG_GET_NEXT_ID,
+ BPF_MAP_GET_NEXT_ID,
+ BPF_PROG_GET_FD_BY_ID,
+ BPF_MAP_GET_FD_BY_ID,
+ BPF_OBJ_GET_INFO_BY_FD,
+ BPF_PROG_QUERY,
+ BPF_RAW_TRACEPOINT_OPEN,
+ BPF_BTF_LOAD,
+ BPF_BTF_GET_FD_BY_ID,
+ BPF_TASK_FD_QUERY,
+ BPF_MAP_LOOKUP_AND_DELETE_ELEM,
+ BPF_MAP_FREEZE,
+ BPF_BTF_GET_NEXT_ID,
+ BPF_MAP_LOOKUP_BATCH,
+ BPF_MAP_LOOKUP_AND_DELETE_BATCH,
+ BPF_MAP_UPDATE_BATCH,
+ BPF_MAP_DELETE_BATCH,
+ BPF_LINK_CREATE,
+ BPF_LINK_UPDATE,
+ BPF_LINK_GET_FD_BY_ID,
+ BPF_LINK_GET_NEXT_ID,
+ BPF_ENABLE_STATS,
+ BPF_ITER_CREATE,
+ BPF_LINK_DETACH,
+ BPF_PROG_BIND_MAP,
+};
+
+enum bpf_map_type {
+ BPF_MAP_TYPE_UNSPEC,
+ BPF_MAP_TYPE_HASH,
+ BPF_MAP_TYPE_ARRAY,
+ BPF_MAP_TYPE_PROG_ARRAY,
+ BPF_MAP_TYPE_PERF_EVENT_ARRAY,
+ BPF_MAP_TYPE_PERCPU_HASH,
+ BPF_MAP_TYPE_PERCPU_ARRAY,
+ BPF_MAP_TYPE_STACK_TRACE,
+ BPF_MAP_TYPE_CGROUP_ARRAY,
+ BPF_MAP_TYPE_LRU_HASH,
+ BPF_MAP_TYPE_LRU_PERCPU_HASH,
+ BPF_MAP_TYPE_LPM_TRIE,
+ BPF_MAP_TYPE_ARRAY_OF_MAPS,
+ BPF_MAP_TYPE_HASH_OF_MAPS,
+ BPF_MAP_TYPE_DEVMAP,
+ BPF_MAP_TYPE_SOCKMAP,
+ BPF_MAP_TYPE_CPUMAP,
+ BPF_MAP_TYPE_XSKMAP,
+ BPF_MAP_TYPE_SOCKHASH,
+ BPF_MAP_TYPE_CGROUP_STORAGE,
+ BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
+ BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
+ BPF_MAP_TYPE_QUEUE,
+ BPF_MAP_TYPE_STACK,
+ BPF_MAP_TYPE_SK_STORAGE,
+ BPF_MAP_TYPE_DEVMAP_HASH,
+ BPF_MAP_TYPE_STRUCT_OPS,
+ BPF_MAP_TYPE_RINGBUF,
+ BPF_MAP_TYPE_INODE_STORAGE,
+};
+
+/* Note that tracing related programs such as
+ * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
+ * are not subject to a stable API since kernel internal data
+ * structures can change from release to release and may
+ * therefore break existing tracing BPF programs. Tracing BPF
+ * programs correspond to /a/ specific kernel which is to be
+ * analyzed, and not /a/ specific kernel /and/ all future ones.
+ */
+enum bpf_prog_type {
+ BPF_PROG_TYPE_UNSPEC,
+ BPF_PROG_TYPE_SOCKET_FILTER,
+ BPF_PROG_TYPE_KPROBE,
+ BPF_PROG_TYPE_SCHED_CLS,
+ BPF_PROG_TYPE_SCHED_ACT,
+ BPF_PROG_TYPE_TRACEPOINT,
+ BPF_PROG_TYPE_XDP,
+ BPF_PROG_TYPE_PERF_EVENT,
+ BPF_PROG_TYPE_CGROUP_SKB,
+ BPF_PROG_TYPE_CGROUP_SOCK,
+ BPF_PROG_TYPE_LWT_IN,
+ BPF_PROG_TYPE_LWT_OUT,
+ BPF_PROG_TYPE_LWT_XMIT,
+ BPF_PROG_TYPE_SOCK_OPS,
+ BPF_PROG_TYPE_SK_SKB,
+ BPF_PROG_TYPE_CGROUP_DEVICE,
+ BPF_PROG_TYPE_SK_MSG,
+ BPF_PROG_TYPE_RAW_TRACEPOINT,
+ BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
+ BPF_PROG_TYPE_LWT_SEG6LOCAL,
+ BPF_PROG_TYPE_LIRC_MODE2,
+ BPF_PROG_TYPE_SK_REUSEPORT,
+ BPF_PROG_TYPE_FLOW_DISSECTOR,
+ BPF_PROG_TYPE_CGROUP_SYSCTL,
+ BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
+ BPF_PROG_TYPE_CGROUP_SOCKOPT,
+ BPF_PROG_TYPE_TRACING,
+ BPF_PROG_TYPE_STRUCT_OPS,
+ BPF_PROG_TYPE_EXT,
+ BPF_PROG_TYPE_LSM,
+ BPF_PROG_TYPE_SK_LOOKUP,
+};
+
+enum bpf_attach_type {
+ BPF_CGROUP_INET_INGRESS,
+ BPF_CGROUP_INET_EGRESS,
+ BPF_CGROUP_INET_SOCK_CREATE,
+ BPF_CGROUP_SOCK_OPS,
+ BPF_SK_SKB_STREAM_PARSER,
+ BPF_SK_SKB_STREAM_VERDICT,
+ BPF_CGROUP_DEVICE,
+ BPF_SK_MSG_VERDICT,
+ BPF_CGROUP_INET4_BIND,
+ BPF_CGROUP_INET6_BIND,
+ BPF_CGROUP_INET4_CONNECT,
+ BPF_CGROUP_INET6_CONNECT,
+ BPF_CGROUP_INET4_POST_BIND,
+ BPF_CGROUP_INET6_POST_BIND,
+ BPF_CGROUP_UDP4_SENDMSG,
+ BPF_CGROUP_UDP6_SENDMSG,
+ BPF_LIRC_MODE2,
+ BPF_FLOW_DISSECTOR,
+ BPF_CGROUP_SYSCTL,
+ BPF_CGROUP_UDP4_RECVMSG,
+ BPF_CGROUP_UDP6_RECVMSG,
+ BPF_CGROUP_GETSOCKOPT,
+ BPF_CGROUP_SETSOCKOPT,
+ BPF_TRACE_RAW_TP,
+ BPF_TRACE_FENTRY,
+ BPF_TRACE_FEXIT,
+ BPF_MODIFY_RETURN,
+ BPF_LSM_MAC,
+ BPF_TRACE_ITER,
+ BPF_CGROUP_INET4_GETPEERNAME,
+ BPF_CGROUP_INET6_GETPEERNAME,
+ BPF_CGROUP_INET4_GETSOCKNAME,
+ BPF_CGROUP_INET6_GETSOCKNAME,
+ BPF_XDP_DEVMAP,
+ BPF_CGROUP_INET_SOCK_RELEASE,
+ BPF_XDP_CPUMAP,
+ BPF_SK_LOOKUP,
+ BPF_XDP,
+ __MAX_BPF_ATTACH_TYPE
+};
+
+#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
+
+enum bpf_link_type {
+ BPF_LINK_TYPE_UNSPEC = 0,
+ BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
+ BPF_LINK_TYPE_TRACING = 2,
+ BPF_LINK_TYPE_CGROUP = 3,
+ BPF_LINK_TYPE_ITER = 4,
+ BPF_LINK_TYPE_NETNS = 5,
+ BPF_LINK_TYPE_XDP = 6,
+
+ MAX_BPF_LINK_TYPE,
+};
+
+/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
+ *
+ * NONE(default): No further bpf programs allowed in the subtree.
+ *
+ * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
+ * the program in this cgroup yields to sub-cgroup program.
+ *
+ * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
+ * that cgroup program gets run in addition to the program in this cgroup.
+ *
+ * Only one program is allowed to be attached to a cgroup with
+ * NONE or BPF_F_ALLOW_OVERRIDE flag.
+ * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
+ * release old program and attach the new one. Attach flags has to match.
+ *
+ * Multiple programs are allowed to be attached to a cgroup with
+ * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
+ * (those that were attached first, run first)
+ * The programs of sub-cgroup are executed first, then programs of
+ * this cgroup and then programs of parent cgroup.
+ * When children program makes decision (like picking TCP CA or sock bind)
+ * parent program has a chance to override it.
+ *
+ * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
+ * programs for a cgroup. Though it's possible to replace an old program at
+ * any position by also specifying BPF_F_REPLACE flag and position itself in
+ * replace_bpf_fd attribute. Old program at this position will be released.
+ *
+ * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
+ * A cgroup with NONE doesn't allow any programs in sub-cgroups.
+ * Ex1:
+ * cgrp1 (MULTI progs A, B) ->
+ * cgrp2 (OVERRIDE prog C) ->
+ * cgrp3 (MULTI prog D) ->
+ * cgrp4 (OVERRIDE prog E) ->
+ * cgrp5 (NONE prog F)
+ * the event in cgrp5 triggers execution of F,D,A,B in that order.
+ * if prog F is detached, the execution is E,D,A,B
+ * if prog F and D are detached, the execution is E,A,B
+ * if prog F, E and D are detached, the execution is C,A,B
+ *
+ * All eligible programs are executed regardless of return code from
+ * earlier programs.
+ */
+#define BPF_F_ALLOW_OVERRIDE (1U << 0)
+#define BPF_F_ALLOW_MULTI (1U << 1)
+#define BPF_F_REPLACE (1U << 2)
+
+/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
+ * verifier will perform strict alignment checking as if the kernel
+ * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
+ * and NET_IP_ALIGN defined to 2.
+ */
+#define BPF_F_STRICT_ALIGNMENT (1U << 0)
+
+/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
+ * verifier will allow any alignment whatsoever. On platforms
+ * with strict alignment requirements for loads ands stores (such
+ * as sparc and mips) the verifier validates that all loads and
+ * stores provably follow this requirement. This flag turns that
+ * checking and enforcement off.
+ *
+ * It is mostly used for testing when we want to validate the
+ * context and memory access aspects of the verifier, but because
+ * of an unaligned access the alignment check would trigger before
+ * the one we are interested in.
+ */
+#define BPF_F_ANY_ALIGNMENT (1U << 1)
+
+/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
+ * Verifier does sub-register def/use analysis and identifies instructions whose
+ * def only matters for low 32-bit, high 32-bit is never referenced later
+ * through implicit zero extension. Therefore verifier notifies JIT back-ends
+ * that it is safe to ignore clearing high 32-bit for these instructions. This
+ * saves some back-ends a lot of code-gen. However such optimization is not
+ * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
+ * hence hasn't used verifier's analysis result. But, we really want to have a
+ * way to be able to verify the correctness of the described optimization on
+ * x86_64 on which testsuites are frequently exercised.
+ *
+ * So, this flag is introduced. Once it is set, verifier will randomize high
+ * 32-bit for those instructions who has been identified as safe to ignore them.
+ * Then, if verifier is not doing correct analysis, such randomization will
+ * regress tests to expose bugs.
+ */
+#define BPF_F_TEST_RND_HI32 (1U << 2)
+
+/* The verifier internal test flag. Behavior is undefined */
+#define BPF_F_TEST_STATE_FREQ (1U << 3)
+
+/* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
+ * restrict map and helper usage for such programs. Sleepable BPF programs can
+ * only be attached to hooks where kernel execution context allows sleeping.
+ * Such programs are allowed to use helpers that may sleep like
+ * bpf_copy_from_user().
+ */
+#define BPF_F_SLEEPABLE (1U << 4)
+
+/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
+ * the following extensions:
+ *
+ * insn[0].src_reg: BPF_PSEUDO_MAP_FD
+ * insn[0].imm: map fd
+ * insn[1].imm: 0
+ * insn[0].off: 0
+ * insn[1].off: 0
+ * ldimm64 rewrite: address of map
+ * verifier type: CONST_PTR_TO_MAP
+ */
+#define BPF_PSEUDO_MAP_FD 1
+/* insn[0].src_reg: BPF_PSEUDO_MAP_VALUE
+ * insn[0].imm: map fd
+ * insn[1].imm: offset into value
+ * insn[0].off: 0
+ * insn[1].off: 0
+ * ldimm64 rewrite: address of map[0]+offset
+ * verifier type: PTR_TO_MAP_VALUE
+ */
+#define BPF_PSEUDO_MAP_VALUE 2
+/* insn[0].src_reg: BPF_PSEUDO_BTF_ID
+ * insn[0].imm: kernel btd id of VAR
+ * insn[1].imm: 0
+ * insn[0].off: 0
+ * insn[1].off: 0
+ * ldimm64 rewrite: address of the kernel variable
+ * verifier type: PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
+ * is struct/union.
+ */
+#define BPF_PSEUDO_BTF_ID 3
+
+/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
+ * offset to another bpf function
+ */
+#define BPF_PSEUDO_CALL 1
+
+/* flags for BPF_MAP_UPDATE_ELEM command */
+enum {
+ BPF_ANY = 0, /* create new element or update existing */
+ BPF_NOEXIST = 1, /* create new element if it didn't exist */
+ BPF_EXIST = 2, /* update existing element */
+ BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */
+};
+
+/* flags for BPF_MAP_CREATE command */
+enum {
+ BPF_F_NO_PREALLOC = (1U << 0),
+/* Instead of having one common LRU list in the
+ * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
+ * which can scale and perform better.
+ * Note, the LRU nodes (including free nodes) cannot be moved
+ * across different LRU lists.
+ */
+ BPF_F_NO_COMMON_LRU = (1U << 1),
+/* Specify numa node during map creation */
+ BPF_F_NUMA_NODE = (1U << 2),
+
+/* Flags for accessing BPF object from syscall side. */
+ BPF_F_RDONLY = (1U << 3),
+ BPF_F_WRONLY = (1U << 4),
+
+/* Flag for stack_map, store build_id+offset instead of pointer */
+ BPF_F_STACK_BUILD_ID = (1U << 5),
+
+/* Zero-initialize hash function seed. This should only be used for testing. */
+ BPF_F_ZERO_SEED = (1U << 6),
+
+/* Flags for accessing BPF object from program side. */
+ BPF_F_RDONLY_PROG = (1U << 7),
+ BPF_F_WRONLY_PROG = (1U << 8),
+
+/* Clone map from listener for newly accepted socket */
+ BPF_F_CLONE = (1U << 9),
+
+/* Enable memory-mapping BPF map */
+ BPF_F_MMAPABLE = (1U << 10),
+
+/* Share perf_event among processes */
+ BPF_F_PRESERVE_ELEMS = (1U << 11),
+
+/* Create a map that is suitable to be an inner map with dynamic max entries */
+ BPF_F_INNER_MAP = (1U << 12),
+};
+
+/* Flags for BPF_PROG_QUERY. */
+
+/* Query effective (directly attached + inherited from ancestor cgroups)
+ * programs that will be executed for events within a cgroup.
+ * attach_flags with this flag are returned only for directly attached programs.
+ */
+#define BPF_F_QUERY_EFFECTIVE (1U << 0)
+
+/* Flags for BPF_PROG_TEST_RUN */
+
+/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
+#define BPF_F_TEST_RUN_ON_CPU (1U << 0)
+
+/* type for BPF_ENABLE_STATS */
+enum bpf_stats_type {
+ /* enabled run_time_ns and run_cnt */
+ BPF_STATS_RUN_TIME = 0,
+};
+
+enum bpf_stack_build_id_status {
+ /* user space need an empty entry to identify end of a trace */
+ BPF_STACK_BUILD_ID_EMPTY = 0,
+ /* with valid build_id and offset */
+ BPF_STACK_BUILD_ID_VALID = 1,
+ /* couldn't get build_id, fallback to ip */
+ BPF_STACK_BUILD_ID_IP = 2,
+};
+
+#define BPF_BUILD_ID_SIZE 20
+struct bpf_stack_build_id {
+ __s32 status;
+ unsigned char build_id[BPF_BUILD_ID_SIZE];
+ union {
+ __u64 offset;
+ __u64 ip;
+ };
+};
+
+#define BPF_OBJ_NAME_LEN 16U
+
+union bpf_attr {
+ struct { /* anonymous struct used by BPF_MAP_CREATE command */
+ __u32 map_type; /* one of enum bpf_map_type */
+ __u32 key_size; /* size of key in bytes */
+ __u32 value_size; /* size of value in bytes */
+ __u32 max_entries; /* max number of entries in a map */
+ __u32 map_flags; /* BPF_MAP_CREATE related
+ * flags defined above.
+ */
+ __u32 inner_map_fd; /* fd pointing to the inner map */
+ __u32 numa_node; /* numa node (effective only if
+ * BPF_F_NUMA_NODE is set).
+ */
+ char map_name[BPF_OBJ_NAME_LEN];
+ __u32 map_ifindex; /* ifindex of netdev to create on */
+ __u32 btf_fd; /* fd pointing to a BTF type data */
+ __u32 btf_key_type_id; /* BTF type_id of the key */
+ __u32 btf_value_type_id; /* BTF type_id of the value */
+ __u32 btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
+ * struct stored as the
+ * map value
+ */
+ };
+
+ struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
+ __u32 map_fd;
+ __aligned_u64 key;
+ union {
+ __aligned_u64 value;
+ __aligned_u64 next_key;
+ };
+ __u64 flags;
+ };
+
+ struct { /* struct used by BPF_MAP_*_BATCH commands */
+ __aligned_u64 in_batch; /* start batch,
+ * NULL to start from beginning
+ */
+ __aligned_u64 out_batch; /* output: next start batch */
+ __aligned_u64 keys;
+ __aligned_u64 values;
+ __u32 count; /* input/output:
+ * input: # of key/value
+ * elements
+ * output: # of filled elements
+ */
+ __u32 map_fd;
+ __u64 elem_flags;
+ __u64 flags;
+ } batch;
+
+ struct { /* anonymous struct used by BPF_PROG_LOAD command */
+ __u32 prog_type; /* one of enum bpf_prog_type */
+ __u32 insn_cnt;
+ __aligned_u64 insns;
+ __aligned_u64 license;
+ __u32 log_level; /* verbosity level of verifier */
+ __u32 log_size; /* size of user buffer */
+ __aligned_u64 log_buf; /* user supplied buffer */
+ __u32 kern_version; /* not used */
+ __u32 prog_flags;
+ char prog_name[BPF_OBJ_NAME_LEN];
+ __u32 prog_ifindex; /* ifindex of netdev to prep for */
+ /* For some prog types expected attach type must be known at
+ * load time to verify attach type specific parts of prog
+ * (context accesses, allowed helpers, etc).
+ */
+ __u32 expected_attach_type;
+ __u32 prog_btf_fd; /* fd pointing to BTF type data */
+ __u32 func_info_rec_size; /* userspace bpf_func_info size */
+ __aligned_u64 func_info; /* func info */
+ __u32 func_info_cnt; /* number of bpf_func_info records */
+ __u32 line_info_rec_size; /* userspace bpf_line_info size */
+ __aligned_u64 line_info; /* line info */
+ __u32 line_info_cnt; /* number of bpf_line_info records */
+ __u32 attach_btf_id; /* in-kernel BTF type id to attach to */
+ __u32 attach_prog_fd; /* 0 to attach to vmlinux */
+ };
+
+ struct { /* anonymous struct used by BPF_OBJ_* commands */
+ __aligned_u64 pathname;
+ __u32 bpf_fd;
+ __u32 file_flags;
+ };
+
+ struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
+ __u32 target_fd; /* container object to attach to */
+ __u32 attach_bpf_fd; /* eBPF program to attach */
+ __u32 attach_type;
+ __u32 attach_flags;
+ __u32 replace_bpf_fd; /* previously attached eBPF
+ * program to replace if
+ * BPF_F_REPLACE is used
+ */
+ };
+
+ struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
+ __u32 prog_fd;
+ __u32 retval;
+ __u32 data_size_in; /* input: len of data_in */
+ __u32 data_size_out; /* input/output: len of data_out
+ * returns ENOSPC if data_out
+ * is too small.
+ */
+ __aligned_u64 data_in;
+ __aligned_u64 data_out;
+ __u32 repeat;
+ __u32 duration;
+ __u32 ctx_size_in; /* input: len of ctx_in */
+ __u32 ctx_size_out; /* input/output: len of ctx_out
+ * returns ENOSPC if ctx_out
+ * is too small.
+ */
+ __aligned_u64 ctx_in;
+ __aligned_u64 ctx_out;
+ __u32 flags;
+ __u32 cpu;
+ } test;
+
+ struct { /* anonymous struct used by BPF_*_GET_*_ID */
+ union {
+ __u32 start_id;
+ __u32 prog_id;
+ __u32 map_id;
+ __u32 btf_id;
+ __u32 link_id;
+ };
+ __u32 next_id;
+ __u32 open_flags;
+ };
+
+ struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
+ __u32 bpf_fd;
+ __u32 info_len;
+ __aligned_u64 info;
+ } info;
+
+ struct { /* anonymous struct used by BPF_PROG_QUERY command */
+ __u32 target_fd; /* container object to query */
+ __u32 attach_type;
+ __u32 query_flags;
+ __u32 attach_flags;
+ __aligned_u64 prog_ids;
+ __u32 prog_cnt;
+ } query;
+
+ struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
+ __u64 name;
+ __u32 prog_fd;
+ } raw_tracepoint;
+
+ struct { /* anonymous struct for BPF_BTF_LOAD */
+ __aligned_u64 btf;
+ __aligned_u64 btf_log_buf;
+ __u32 btf_size;
+ __u32 btf_log_size;
+ __u32 btf_log_level;
+ };
+
+ struct {
+ __u32 pid; /* input: pid */
+ __u32 fd; /* input: fd */
+ __u32 flags; /* input: flags */
+ __u32 buf_len; /* input/output: buf len */
+ __aligned_u64 buf; /* input/output:
+ * tp_name for tracepoint
+ * symbol for kprobe
+ * filename for uprobe
+ */
+ __u32 prog_id; /* output: prod_id */
+ __u32 fd_type; /* output: BPF_FD_TYPE_* */
+ __u64 probe_offset; /* output: probe_offset */
+ __u64 probe_addr; /* output: probe_addr */
+ } task_fd_query;
+
+ struct { /* struct used by BPF_LINK_CREATE command */
+ __u32 prog_fd; /* eBPF program to attach */
+ union {
+ __u32 target_fd; /* object to attach to */
+ __u32 target_ifindex; /* target ifindex */
+ };
+ __u32 attach_type; /* attach type */
+ __u32 flags; /* extra flags */
+ union {
+ __u32 target_btf_id; /* btf_id of target to attach to */
+ struct {
+ __aligned_u64 iter_info; /* extra bpf_iter_link_info */
+ __u32 iter_info_len; /* iter_info length */
+ };
+ };
+ } link_create;
+
+ struct { /* struct used by BPF_LINK_UPDATE command */
+ __u32 link_fd; /* link fd */
+ /* new program fd to update link with */
+ __u32 new_prog_fd;
+ __u32 flags; /* extra flags */
+ /* expected link's program fd; is specified only if
+ * BPF_F_REPLACE flag is set in flags */
+ __u32 old_prog_fd;
+ } link_update;
+
+ struct {
+ __u32 link_fd;
+ } link_detach;
+
+ struct { /* struct used by BPF_ENABLE_STATS command */
+ __u32 type;
+ } enable_stats;
+
+ struct { /* struct used by BPF_ITER_CREATE command */
+ __u32 link_fd;
+ __u32 flags;
+ } iter_create;
+
+ struct { /* struct used by BPF_PROG_BIND_MAP command */
+ __u32 prog_fd;
+ __u32 map_fd;
+ __u32 flags; /* extra flags */
+ } prog_bind_map;
+
+} __attribute__((aligned(8)));
+
+/* The description below is an attempt at providing documentation to eBPF
+ * developers about the multiple available eBPF helper functions. It can be
+ * parsed and used to produce a manual page. The workflow is the following,
+ * and requires the rst2man utility:
+ *
+ * $ ./scripts/bpf_helpers_doc.py \
+ * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
+ * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
+ * $ man /tmp/bpf-helpers.7
+ *
+ * Note that in order to produce this external documentation, some RST
+ * formatting is used in the descriptions to get "bold" and "italics" in
+ * manual pages. Also note that the few trailing white spaces are
+ * intentional, removing them would break paragraphs for rst2man.
+ *
+ * Start of BPF helper function descriptions:
+ *
+ * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
+ * Description
+ * Perform a lookup in *map* for an entry associated to *key*.
+ * Return
+ * Map value associated to *key*, or **NULL** if no entry was
+ * found.
+ *
+ * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
+ * Description
+ * Add or update the value of the entry associated to *key* in
+ * *map* with *value*. *flags* is one of:
+ *
+ * **BPF_NOEXIST**
+ * The entry for *key* must not exist in the map.
+ * **BPF_EXIST**
+ * The entry for *key* must already exist in the map.
+ * **BPF_ANY**
+ * No condition on the existence of the entry for *key*.
+ *
+ * Flag value **BPF_NOEXIST** cannot be used for maps of types
+ * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
+ * elements always exist), the helper would return an error.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
+ * Description
+ * Delete entry with *key* from *map*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * For tracing programs, safely attempt to read *size* bytes from
+ * kernel space address *unsafe_ptr* and store the data in *dst*.
+ *
+ * Generally, use **bpf_probe_read_user**\ () or
+ * **bpf_probe_read_kernel**\ () instead.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_ktime_get_ns(void)
+ * Description
+ * Return the time elapsed since system boot, in nanoseconds.
+ * Does not include time the system was suspended.
+ * See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
+ * Return
+ * Current *ktime*.
+ *
+ * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
+ * Description
+ * This helper is a "printk()-like" facility for debugging. It
+ * prints a message defined by format *fmt* (of size *fmt_size*)
+ * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
+ * available. It can take up to three additional **u64**
+ * arguments (as an eBPF helpers, the total number of arguments is
+ * limited to five).
+ *
+ * Each time the helper is called, it appends a line to the trace.
+ * Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
+ * open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
+ * The format of the trace is customizable, and the exact output
+ * one will get depends on the options set in
+ * *\/sys/kernel/debug/tracing/trace_options* (see also the
+ * *README* file under the same directory). However, it usually
+ * defaults to something like:
+ *
+ * ::
+ *
+ * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
+ *
+ * In the above:
+ *
+ * * ``telnet`` is the name of the current task.
+ * * ``470`` is the PID of the current task.
+ * * ``001`` is the CPU number on which the task is
+ * running.
+ * * In ``.N..``, each character refers to a set of
+ * options (whether irqs are enabled, scheduling
+ * options, whether hard/softirqs are running, level of
+ * preempt_disabled respectively). **N** means that
+ * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
+ * are set.
+ * * ``419421.045894`` is a timestamp.
+ * * ``0x00000001`` is a fake value used by BPF for the
+ * instruction pointer register.
+ * * ``<formatted msg>`` is the message formatted with
+ * *fmt*.
+ *
+ * The conversion specifiers supported by *fmt* are similar, but
+ * more limited than for printk(). They are **%d**, **%i**,
+ * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
+ * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
+ * of field, padding with zeroes, etc.) is available, and the
+ * helper will return **-EINVAL** (but print nothing) if it
+ * encounters an unknown specifier.
+ *
+ * Also, note that **bpf_trace_printk**\ () is slow, and should
+ * only be used for debugging purposes. For this reason, a notice
+ * block (spanning several lines) is printed to kernel logs and
+ * states that the helper should not be used "for production use"
+ * the first time this helper is used (or more precisely, when
+ * **trace_printk**\ () buffers are allocated). For passing values
+ * to user space, perf events should be preferred.
+ * Return
+ * The number of bytes written to the buffer, or a negative error
+ * in case of failure.
+ *
+ * u32 bpf_get_prandom_u32(void)
+ * Description
+ * Get a pseudo-random number.
+ *
+ * From a security point of view, this helper uses its own
+ * pseudo-random internal state, and cannot be used to infer the
+ * seed of other random functions in the kernel. However, it is
+ * essential to note that the generator used by the helper is not
+ * cryptographically secure.
+ * Return
+ * A random 32-bit unsigned value.
+ *
+ * u32 bpf_get_smp_processor_id(void)
+ * Description
+ * Get the SMP (symmetric multiprocessing) processor id. Note that
+ * all programs run with preemption disabled, which means that the
+ * SMP processor id is stable during all the execution of the
+ * program.
+ * Return
+ * The SMP id of the processor running the program.
+ *
+ * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
+ * Description
+ * Store *len* bytes from address *from* into the packet
+ * associated to *skb*, at *offset*. *flags* are a combination of
+ * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
+ * checksum for the packet after storing the bytes) and
+ * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
+ * **->swhash** and *skb*\ **->l4hash** to 0).
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
+ * Description
+ * Recompute the layer 3 (e.g. IP) checksum for the packet
+ * associated to *skb*. Computation is incremental, so the helper
+ * must know the former value of the header field that was
+ * modified (*from*), the new value of this field (*to*), and the
+ * number of bytes (2 or 4) for this field, stored in *size*.
+ * Alternatively, it is possible to store the difference between
+ * the previous and the new values of the header field in *to*, by
+ * setting *from* and *size* to 0. For both methods, *offset*
+ * indicates the location of the IP checksum within the packet.
+ *
+ * This helper works in combination with **bpf_csum_diff**\ (),
+ * which does not update the checksum in-place, but offers more
+ * flexibility and can handle sizes larger than 2 or 4 for the
+ * checksum to update.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
+ * Description
+ * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
+ * packet associated to *skb*. Computation is incremental, so the
+ * helper must know the former value of the header field that was
+ * modified (*from*), the new value of this field (*to*), and the
+ * number of bytes (2 or 4) for this field, stored on the lowest
+ * four bits of *flags*. Alternatively, it is possible to store
+ * the difference between the previous and the new values of the
+ * header field in *to*, by setting *from* and the four lowest
+ * bits of *flags* to 0. For both methods, *offset* indicates the
+ * location of the IP checksum within the packet. In addition to
+ * the size of the field, *flags* can be added (bitwise OR) actual
+ * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
+ * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
+ * for updates resulting in a null checksum the value is set to
+ * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
+ * the checksum is to be computed against a pseudo-header.
+ *
+ * This helper works in combination with **bpf_csum_diff**\ (),
+ * which does not update the checksum in-place, but offers more
+ * flexibility and can handle sizes larger than 2 or 4 for the
+ * checksum to update.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
+ * Description
+ * This special helper is used to trigger a "tail call", or in
+ * other words, to jump into another eBPF program. The same stack
+ * frame is used (but values on stack and in registers for the
+ * caller are not accessible to the callee). This mechanism allows
+ * for program chaining, either for raising the maximum number of
+ * available eBPF instructions, or to execute given programs in
+ * conditional blocks. For security reasons, there is an upper
+ * limit to the number of successive tail calls that can be
+ * performed.
+ *
+ * Upon call of this helper, the program attempts to jump into a
+ * program referenced at index *index* in *prog_array_map*, a
+ * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
+ * *ctx*, a pointer to the context.
+ *
+ * If the call succeeds, the kernel immediately runs the first
+ * instruction of the new program. This is not a function call,
+ * and it never returns to the previous program. If the call
+ * fails, then the helper has no effect, and the caller continues
+ * to run its subsequent instructions. A call can fail if the
+ * destination program for the jump does not exist (i.e. *index*
+ * is superior to the number of entries in *prog_array_map*), or
+ * if the maximum number of tail calls has been reached for this
+ * chain of programs. This limit is defined in the kernel by the
+ * macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
+ * which is currently set to 32.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
+ * Description
+ * Clone and redirect the packet associated to *skb* to another
+ * net device of index *ifindex*. Both ingress and egress
+ * interfaces can be used for redirection. The **BPF_F_INGRESS**
+ * value in *flags* is used to make the distinction (ingress path
+ * is selected if the flag is present, egress path otherwise).
+ * This is the only flag supported for now.
+ *
+ * In comparison with **bpf_redirect**\ () helper,
+ * **bpf_clone_redirect**\ () has the associated cost of
+ * duplicating the packet buffer, but this can be executed out of
+ * the eBPF program. Conversely, **bpf_redirect**\ () is more
+ * efficient, but it is handled through an action code where the
+ * redirection happens only after the eBPF program has returned.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_get_current_pid_tgid(void)
+ * Return
+ * A 64-bit integer containing the current tgid and pid, and
+ * created as such:
+ * *current_task*\ **->tgid << 32 \|**
+ * *current_task*\ **->pid**.
+ *
+ * u64 bpf_get_current_uid_gid(void)
+ * Return
+ * A 64-bit integer containing the current GID and UID, and
+ * created as such: *current_gid* **<< 32 \|** *current_uid*.
+ *
+ * long bpf_get_current_comm(void *buf, u32 size_of_buf)
+ * Description
+ * Copy the **comm** attribute of the current task into *buf* of
+ * *size_of_buf*. The **comm** attribute contains the name of
+ * the executable (excluding the path) for the current task. The
+ * *size_of_buf* must be strictly positive. On success, the
+ * helper makes sure that the *buf* is NUL-terminated. On failure,
+ * it is filled with zeroes.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
+ * Description
+ * Retrieve the classid for the current task, i.e. for the net_cls
+ * cgroup to which *skb* belongs.
+ *
+ * This helper can be used on TC egress path, but not on ingress.
+ *
+ * The net_cls cgroup provides an interface to tag network packets
+ * based on a user-provided identifier for all traffic coming from
+ * the tasks belonging to the related cgroup. See also the related
+ * kernel documentation, available from the Linux sources in file
+ * *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
+ *
+ * The Linux kernel has two versions for cgroups: there are
+ * cgroups v1 and cgroups v2. Both are available to users, who can
+ * use a mixture of them, but note that the net_cls cgroup is for
+ * cgroup v1 only. This makes it incompatible with BPF programs
+ * run on cgroups, which is a cgroup-v2-only feature (a socket can
+ * only hold data for one version of cgroups at a time).
+ *
+ * This helper is only available is the kernel was compiled with
+ * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
+ * "**y**" or to "**m**".
+ * Return
+ * The classid, or 0 for the default unconfigured classid.
+ *
+ * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
+ * Description
+ * Push a *vlan_tci* (VLAN tag control information) of protocol
+ * *vlan_proto* to the packet associated to *skb*, then update
+ * the checksum. Note that if *vlan_proto* is different from
+ * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
+ * be **ETH_P_8021Q**.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_vlan_pop(struct sk_buff *skb)
+ * Description
+ * Pop a VLAN header from the packet associated to *skb*.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
+ * Description
+ * Get tunnel metadata. This helper takes a pointer *key* to an
+ * empty **struct bpf_tunnel_key** of **size**, that will be
+ * filled with tunnel metadata for the packet associated to *skb*.
+ * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
+ * indicates that the tunnel is based on IPv6 protocol instead of
+ * IPv4.
+ *
+ * The **struct bpf_tunnel_key** is an object that generalizes the
+ * principal parameters used by various tunneling protocols into a
+ * single struct. This way, it can be used to easily make a
+ * decision based on the contents of the encapsulation header,
+ * "summarized" in this struct. In particular, it holds the IP
+ * address of the remote end (IPv4 or IPv6, depending on the case)
+ * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
+ * this struct exposes the *key*\ **->tunnel_id**, which is
+ * generally mapped to a VNI (Virtual Network Identifier), making
+ * it programmable together with the **bpf_skb_set_tunnel_key**\
+ * () helper.
+ *
+ * Let's imagine that the following code is part of a program
+ * attached to the TC ingress interface, on one end of a GRE
+ * tunnel, and is supposed to filter out all messages coming from
+ * remote ends with IPv4 address other than 10.0.0.1:
+ *
+ * ::
+ *
+ * int ret;
+ * struct bpf_tunnel_key key = {};
+ *
+ * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
+ * if (ret < 0)
+ * return TC_ACT_SHOT; // drop packet
+ *
+ * if (key.remote_ipv4 != 0x0a000001)
+ * return TC_ACT_SHOT; // drop packet
+ *
+ * return TC_ACT_OK; // accept packet
+ *
+ * This interface can also be used with all encapsulation devices
+ * that can operate in "collect metadata" mode: instead of having
+ * one network device per specific configuration, the "collect
+ * metadata" mode only requires a single device where the
+ * configuration can be extracted from this helper.
+ *
+ * This can be used together with various tunnels such as VXLan,
+ * Geneve, GRE or IP in IP (IPIP).
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
+ * Description
+ * Populate tunnel metadata for packet associated to *skb.* The
+ * tunnel metadata is set to the contents of *key*, of *size*. The
+ * *flags* can be set to a combination of the following values:
+ *
+ * **BPF_F_TUNINFO_IPV6**
+ * Indicate that the tunnel is based on IPv6 protocol
+ * instead of IPv4.
+ * **BPF_F_ZERO_CSUM_TX**
+ * For IPv4 packets, add a flag to tunnel metadata
+ * indicating that checksum computation should be skipped
+ * and checksum set to zeroes.
+ * **BPF_F_DONT_FRAGMENT**
+ * Add a flag to tunnel metadata indicating that the
+ * packet should not be fragmented.
+ * **BPF_F_SEQ_NUMBER**
+ * Add a flag to tunnel metadata indicating that a
+ * sequence number should be added to tunnel header before
+ * sending the packet. This flag was added for GRE
+ * encapsulation, but might be used with other protocols
+ * as well in the future.
+ *
+ * Here is a typical usage on the transmit path:
+ *
+ * ::
+ *
+ * struct bpf_tunnel_key key;
+ * populate key ...
+ * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
+ * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
+ *
+ * See also the description of the **bpf_skb_get_tunnel_key**\ ()
+ * helper for additional information.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
+ * Description
+ * Read the value of a perf event counter. This helper relies on a
+ * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
+ * the perf event counter is selected when *map* is updated with
+ * perf event file descriptors. The *map* is an array whose size
+ * is the number of available CPUs, and each cell contains a value
+ * relative to one CPU. The value to retrieve is indicated by
+ * *flags*, that contains the index of the CPU to look up, masked
+ * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
+ * **BPF_F_CURRENT_CPU** to indicate that the value for the
+ * current CPU should be retrieved.
+ *
+ * Note that before Linux 4.13, only hardware perf event can be
+ * retrieved.
+ *
+ * Also, be aware that the newer helper
+ * **bpf_perf_event_read_value**\ () is recommended over
+ * **bpf_perf_event_read**\ () in general. The latter has some ABI
+ * quirks where error and counter value are used as a return code
+ * (which is wrong to do since ranges may overlap). This issue is
+ * fixed with **bpf_perf_event_read_value**\ (), which at the same
+ * time provides more features over the **bpf_perf_event_read**\
+ * () interface. Please refer to the description of
+ * **bpf_perf_event_read_value**\ () for details.
+ * Return
+ * The value of the perf event counter read from the map, or a
+ * negative error code in case of failure.
+ *
+ * long bpf_redirect(u32 ifindex, u64 flags)
+ * Description
+ * Redirect the packet to another net device of index *ifindex*.
+ * This helper is somewhat similar to **bpf_clone_redirect**\
+ * (), except that the packet is not cloned, which provides
+ * increased performance.
+ *
+ * Except for XDP, both ingress and egress interfaces can be used
+ * for redirection. The **BPF_F_INGRESS** value in *flags* is used
+ * to make the distinction (ingress path is selected if the flag
+ * is present, egress path otherwise). Currently, XDP only
+ * supports redirection to the egress interface, and accepts no
+ * flag at all.
+ *
+ * The same effect can also be attained with the more generic
+ * **bpf_redirect_map**\ (), which uses a BPF map to store the
+ * redirect target instead of providing it directly to the helper.
+ * Return
+ * For XDP, the helper returns **XDP_REDIRECT** on success or
+ * **XDP_ABORTED** on error. For other program types, the values
+ * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
+ * error.
+ *
+ * u32 bpf_get_route_realm(struct sk_buff *skb)
+ * Description
+ * Retrieve the realm or the route, that is to say the
+ * **tclassid** field of the destination for the *skb*. The
+ * identifier retrieved is a user-provided tag, similar to the
+ * one used with the net_cls cgroup (see description for
+ * **bpf_get_cgroup_classid**\ () helper), but here this tag is
+ * held by a route (a destination entry), not by a task.
+ *
+ * Retrieving this identifier works with the clsact TC egress hook
+ * (see also **tc-bpf(8)**), or alternatively on conventional
+ * classful egress qdiscs, but not on TC ingress path. In case of
+ * clsact TC egress hook, this has the advantage that, internally,
+ * the destination entry has not been dropped yet in the transmit
+ * path. Therefore, the destination entry does not need to be
+ * artificially held via **netif_keep_dst**\ () for a classful
+ * qdisc until the *skb* is freed.
+ *
+ * This helper is available only if the kernel was compiled with
+ * **CONFIG_IP_ROUTE_CLASSID** configuration option.
+ * Return
+ * The realm of the route for the packet associated to *skb*, or 0
+ * if none was found.
+ *
+ * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
+ * Description
+ * Write raw *data* blob into a special BPF perf event held by
+ * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * event must have the following attributes: **PERF_SAMPLE_RAW**
+ * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * The *flags* are used to indicate the index in *map* for which
+ * the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * to indicate that the index of the current CPU core should be
+ * used.
+ *
+ * The value to write, of *size*, is passed through eBPF stack and
+ * pointed by *data*.
+ *
+ * The context of the program *ctx* needs also be passed to the
+ * helper.
+ *
+ * On user space, a program willing to read the values needs to
+ * call **perf_event_open**\ () on the perf event (either for
+ * one or for all CPUs) and to store the file descriptor into the
+ * *map*. This must be done before the eBPF program can send data
+ * into it. An example is available in file
+ * *samples/bpf/trace_output_user.c* in the Linux kernel source
+ * tree (the eBPF program counterpart is in
+ * *samples/bpf/trace_output_kern.c*).
+ *
+ * **bpf_perf_event_output**\ () achieves better performance
+ * than **bpf_trace_printk**\ () for sharing data with user
+ * space, and is much better suitable for streaming data from eBPF
+ * programs.
+ *
+ * Note that this helper is not restricted to tracing use cases
+ * and can be used with programs attached to TC or XDP as well,
+ * where it allows for passing data to user space listeners. Data
+ * can be:
+ *
+ * * Only custom structs,
+ * * Only the packet payload, or
+ * * A combination of both.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
+ * Description
+ * This helper was provided as an easy way to load data from a
+ * packet. It can be used to load *len* bytes from *offset* from
+ * the packet associated to *skb*, into the buffer pointed by
+ * *to*.
+ *
+ * Since Linux 4.7, usage of this helper has mostly been replaced
+ * by "direct packet access", enabling packet data to be
+ * manipulated with *skb*\ **->data** and *skb*\ **->data_end**
+ * pointing respectively to the first byte of packet data and to
+ * the byte after the last byte of packet data. However, it
+ * remains useful if one wishes to read large quantities of data
+ * at once from a packet into the eBPF stack.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
+ * Description
+ * Walk a user or a kernel stack and return its id. To achieve
+ * this, the helper needs *ctx*, which is a pointer to the context
+ * on which the tracing program is executed, and a pointer to a
+ * *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
+ *
+ * The last argument, *flags*, holds the number of stack frames to
+ * skip (from 0 to 255), masked with
+ * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * a combination of the following flags:
+ *
+ * **BPF_F_USER_STACK**
+ * Collect a user space stack instead of a kernel stack.
+ * **BPF_F_FAST_STACK_CMP**
+ * Compare stacks by hash only.
+ * **BPF_F_REUSE_STACKID**
+ * If two different stacks hash into the same *stackid*,
+ * discard the old one.
+ *
+ * The stack id retrieved is a 32 bit long integer handle which
+ * can be further combined with other data (including other stack
+ * ids) and used as a key into maps. This can be useful for
+ * generating a variety of graphs (such as flame graphs or off-cpu
+ * graphs).
+ *
+ * For walking a stack, this helper is an improvement over
+ * **bpf_probe_read**\ (), which can be used with unrolled loops
+ * but is not efficient and consumes a lot of eBPF instructions.
+ * Instead, **bpf_get_stackid**\ () can collect up to
+ * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
+ * this limit can be controlled with the **sysctl** program, and
+ * that it should be manually increased in order to profile long
+ * user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * ::
+ *
+ * # sysctl kernel.perf_event_max_stack=<new value>
+ * Return
+ * The positive or null stack id on success, or a negative error
+ * in case of failure.
+ *
+ * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
+ * Description
+ * Compute a checksum difference, from the raw buffer pointed by
+ * *from*, of length *from_size* (that must be a multiple of 4),
+ * towards the raw buffer pointed by *to*, of size *to_size*
+ * (same remark). An optional *seed* can be added to the value
+ * (this can be cascaded, the seed may come from a previous call
+ * to the helper).
+ *
+ * This is flexible enough to be used in several ways:
+ *
+ * * With *from_size* == 0, *to_size* > 0 and *seed* set to
+ * checksum, it can be used when pushing new data.
+ * * With *from_size* > 0, *to_size* == 0 and *seed* set to
+ * checksum, it can be used when removing data from a packet.
+ * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
+ * can be used to compute a diff. Note that *from_size* and
+ * *to_size* do not need to be equal.
+ *
+ * This helper can be used in combination with
+ * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
+ * which one can feed in the difference computed with
+ * **bpf_csum_diff**\ ().
+ * Return
+ * The checksum result, or a negative error code in case of
+ * failure.
+ *
+ * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
+ * Description
+ * Retrieve tunnel options metadata for the packet associated to
+ * *skb*, and store the raw tunnel option data to the buffer *opt*
+ * of *size*.
+ *
+ * This helper can be used with encapsulation devices that can
+ * operate in "collect metadata" mode (please refer to the related
+ * note in the description of **bpf_skb_get_tunnel_key**\ () for
+ * more details). A particular example where this can be used is
+ * in combination with the Geneve encapsulation protocol, where it
+ * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
+ * and retrieving arbitrary TLVs (Type-Length-Value headers) from
+ * the eBPF program. This allows for full customization of these
+ * headers.
+ * Return
+ * The size of the option data retrieved.
+ *
+ * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
+ * Description
+ * Set tunnel options metadata for the packet associated to *skb*
+ * to the option data contained in the raw buffer *opt* of *size*.
+ *
+ * See also the description of the **bpf_skb_get_tunnel_opt**\ ()
+ * helper for additional information.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
+ * Description
+ * Change the protocol of the *skb* to *proto*. Currently
+ * supported are transition from IPv4 to IPv6, and from IPv6 to
+ * IPv4. The helper takes care of the groundwork for the
+ * transition, including resizing the socket buffer. The eBPF
+ * program is expected to fill the new headers, if any, via
+ * **skb_store_bytes**\ () and to recompute the checksums with
+ * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
+ * (). The main case for this helper is to perform NAT64
+ * operations out of an eBPF program.
+ *
+ * Internally, the GSO type is marked as dodgy so that headers are
+ * checked and segments are recalculated by the GSO/GRO engine.
+ * The size for GSO target is adapted as well.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
+ * Description
+ * Change the packet type for the packet associated to *skb*. This
+ * comes down to setting *skb*\ **->pkt_type** to *type*, except
+ * the eBPF program does not have a write access to *skb*\
+ * **->pkt_type** beside this helper. Using a helper here allows
+ * for graceful handling of errors.
+ *
+ * The major use case is to change incoming *skb*s to
+ * **PACKET_HOST** in a programmatic way instead of having to
+ * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
+ * example.
+ *
+ * Note that *type* only allows certain values. At this time, they
+ * are:
+ *
+ * **PACKET_HOST**
+ * Packet is for us.
+ * **PACKET_BROADCAST**
+ * Send packet to all.
+ * **PACKET_MULTICAST**
+ * Send packet to group.
+ * **PACKET_OTHERHOST**
+ * Send packet to someone else.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
+ * Description
+ * Check whether *skb* is a descendant of the cgroup2 held by
+ * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
+ * Return
+ * The return value depends on the result of the test, and can be:
+ *
+ * * 0, if the *skb* failed the cgroup2 descendant test.
+ * * 1, if the *skb* succeeded the cgroup2 descendant test.
+ * * A negative error code, if an error occurred.
+ *
+ * u32 bpf_get_hash_recalc(struct sk_buff *skb)
+ * Description
+ * Retrieve the hash of the packet, *skb*\ **->hash**. If it is
+ * not set, in particular if the hash was cleared due to mangling,
+ * recompute this hash. Later accesses to the hash can be done
+ * directly with *skb*\ **->hash**.
+ *
+ * Calling **bpf_set_hash_invalid**\ (), changing a packet
+ * prototype with **bpf_skb_change_proto**\ (), or calling
+ * **bpf_skb_store_bytes**\ () with the
+ * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
+ * the hash and to trigger a new computation for the next call to
+ * **bpf_get_hash_recalc**\ ().
+ * Return
+ * The 32-bit hash.
+ *
+ * u64 bpf_get_current_task(void)
+ * Return
+ * A pointer to the current task struct.
+ *
+ * long bpf_probe_write_user(void *dst, const void *src, u32 len)
+ * Description
+ * Attempt in a safe way to write *len* bytes from the buffer
+ * *src* to *dst* in memory. It only works for threads that are in
+ * user context, and *dst* must be a valid user space address.
+ *
+ * This helper should not be used to implement any kind of
+ * security mechanism because of TOC-TOU attacks, but rather to
+ * debug, divert, and manipulate execution of semi-cooperative
+ * processes.
+ *
+ * Keep in mind that this feature is meant for experiments, and it
+ * has a risk of crashing the system and running programs.
+ * Therefore, when an eBPF program using this helper is attached,
+ * a warning including PID and process name is printed to kernel
+ * logs.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
+ * Description
+ * Check whether the probe is being run is the context of a given
+ * subset of the cgroup2 hierarchy. The cgroup2 to test is held by
+ * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
+ * Return
+ * The return value depends on the result of the test, and can be:
+ *
+ * * 0, if current task belongs to the cgroup2.
+ * * 1, if current task does not belong to the cgroup2.
+ * * A negative error code, if an error occurred.
+ *
+ * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
+ * Description
+ * Resize (trim or grow) the packet associated to *skb* to the
+ * new *len*. The *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * The basic idea is that the helper performs the needed work to
+ * change the size of the packet, then the eBPF program rewrites
+ * the rest via helpers like **bpf_skb_store_bytes**\ (),
+ * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
+ * and others. This helper is a slow path utility intended for
+ * replies with control messages. And because it is targeted for
+ * slow path, the helper itself can afford to be slow: it
+ * implicitly linearizes, unclones and drops offloads from the
+ * *skb*.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
+ * Description
+ * Pull in non-linear data in case the *skb* is non-linear and not
+ * all of *len* are part of the linear section. Make *len* bytes
+ * from *skb* readable and writable. If a zero value is passed for
+ * *len*, then the whole length of the *skb* is pulled.
+ *
+ * This helper is only needed for reading and writing with direct
+ * packet access.
+ *
+ * For direct packet access, testing that offsets to access
+ * are within packet boundaries (test on *skb*\ **->data_end**) is
+ * susceptible to fail if offsets are invalid, or if the requested
+ * data is in non-linear parts of the *skb*. On failure the
+ * program can just bail out, or in the case of a non-linear
+ * buffer, use a helper to make the data available. The
+ * **bpf_skb_load_bytes**\ () helper is a first solution to access
+ * the data. Another one consists in using **bpf_skb_pull_data**
+ * to pull in once the non-linear parts, then retesting and
+ * eventually access the data.
+ *
+ * At the same time, this also makes sure the *skb* is uncloned,
+ * which is a necessary condition for direct write. As this needs
+ * to be an invariant for the write part only, the verifier
+ * detects writes and adds a prologue that is calling
+ * **bpf_skb_pull_data()** to effectively unclone the *skb* from
+ * the very beginning in case it is indeed cloned.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
+ * Description
+ * Add the checksum *csum* into *skb*\ **->csum** in case the
+ * driver has supplied a checksum for the entire packet into that
+ * field. Return an error otherwise. This helper is intended to be
+ * used in combination with **bpf_csum_diff**\ (), in particular
+ * when the checksum needs to be updated after data has been
+ * written into the packet through direct packet access.
+ * Return
+ * The checksum on success, or a negative error code in case of
+ * failure.
+ *
+ * void bpf_set_hash_invalid(struct sk_buff *skb)
+ * Description
+ * Invalidate the current *skb*\ **->hash**. It can be used after
+ * mangling on headers through direct packet access, in order to
+ * indicate that the hash is outdated and to trigger a
+ * recalculation the next time the kernel tries to access this
+ * hash or when the **bpf_get_hash_recalc**\ () helper is called.
+ *
+ * long bpf_get_numa_node_id(void)
+ * Description
+ * Return the id of the current NUMA node. The primary use case
+ * for this helper is the selection of sockets for the local NUMA
+ * node, when the program is attached to sockets using the
+ * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
+ * but the helper is also available to other eBPF program types,
+ * similarly to **bpf_get_smp_processor_id**\ ().
+ * Return
+ * The id of current NUMA node.
+ *
+ * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
+ * Description
+ * Grows headroom of packet associated to *skb* and adjusts the
+ * offset of the MAC header accordingly, adding *len* bytes of
+ * space. It automatically extends and reallocates memory as
+ * required.
+ *
+ * This helper can be used on a layer 3 *skb* to push a MAC header
+ * for redirection into a layer 2 device.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
+ * Description
+ * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
+ * it is possible to use a negative value for *delta*. This helper
+ * can be used to prepare the packet for pushing or popping
+ * headers.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * Copy a NUL terminated string from an unsafe kernel address
+ * *unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
+ * more details.
+ *
+ * Generally, use **bpf_probe_read_user_str**\ () or
+ * **bpf_probe_read_kernel_str**\ () instead.
+ * Return
+ * On success, the strictly positive length of the string,
+ * including the trailing NUL character. On error, a negative
+ * value.
+ *
+ * u64 bpf_get_socket_cookie(struct sk_buff *skb)
+ * Description
+ * If the **struct sk_buff** pointed by *skb* has a known socket,
+ * retrieve the cookie (generated by the kernel) of this socket.
+ * If no cookie has been set yet, generate a new cookie. Once
+ * generated, the socket cookie remains stable for the life of the
+ * socket. This helper can be useful for monitoring per socket
+ * networking traffic statistics as it provides a global socket
+ * identifier that can be assumed unique.
+ * Return
+ * A 8-byte long non-decreasing number on success, or 0 if the
+ * socket field is missing inside *skb*.
+ *
+ * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
+ * Description
+ * Equivalent to bpf_get_socket_cookie() helper that accepts
+ * *skb*, but gets socket from **struct bpf_sock_addr** context.
+ * Return
+ * A 8-byte long non-decreasing number.
+ *
+ * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
+ * Description
+ * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
+ * *skb*, but gets socket from **struct bpf_sock_ops** context.
+ * Return
+ * A 8-byte long non-decreasing number.
+ *
+ * u32 bpf_get_socket_uid(struct sk_buff *skb)
+ * Return
+ * The owner UID of the socket associated to *skb*. If the socket
+ * is **NULL**, or if it is not a full socket (i.e. if it is a
+ * time-wait or a request socket instead), **overflowuid** value
+ * is returned (note that **overflowuid** might also be the actual
+ * UID value for the socket).
+ *
+ * long bpf_set_hash(struct sk_buff *skb, u32 hash)
+ * Description
+ * Set the full hash for *skb* (set the field *skb*\ **->hash**)
+ * to value *hash*.
+ * Return
+ * 0
+ *
+ * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
+ * Description
+ * Emulate a call to **setsockopt()** on the socket associated to
+ * *bpf_socket*, which must be a full socket. The *level* at
+ * which the option resides and the name *optname* of the option
+ * must be specified, see **setsockopt(2)** for more information.
+ * The option value of length *optlen* is pointed by *optval*.
+ *
+ * *bpf_socket* should be one of the following:
+ *
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
+ * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
+ * and **BPF_CGROUP_INET6_CONNECT**.
+ *
+ * This helper actually implements a subset of **setsockopt()**.
+ * It supports the following *level*\ s:
+ *
+ * * **SOL_SOCKET**, which supports the following *optname*\ s:
+ * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
+ * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
+ * **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
+ * * **IPPROTO_TCP**, which supports the following *optname*\ s:
+ * **TCP_CONGESTION**, **TCP_BPF_IW**,
+ * **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
+ * **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
+ * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
+ * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
+ * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
+ * Description
+ * Grow or shrink the room for data in the packet associated to
+ * *skb* by *len_diff*, and according to the selected *mode*.
+ *
+ * By default, the helper will reset any offloaded checksum
+ * indicator of the skb to CHECKSUM_NONE. This can be avoided
+ * by the following flag:
+ *
+ * * **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
+ * checksum data of the skb to CHECKSUM_NONE.
+ *
+ * There are two supported modes at this time:
+ *
+ * * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
+ * (room space is added or removed below the layer 2 header).
+ *
+ * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
+ * (room space is added or removed below the layer 3 header).
+ *
+ * The following flags are supported at this time:
+ *
+ * * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
+ * Adjusting mss in this way is not allowed for datagrams.
+ *
+ * * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
+ * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
+ * Any new space is reserved to hold a tunnel header.
+ * Configure skb offsets and other fields accordingly.
+ *
+ * * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
+ * **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
+ * Use with ENCAP_L3 flags to further specify the tunnel type.
+ *
+ * * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
+ * Use with ENCAP_L3/L4 flags to further specify the tunnel
+ * type; *len* is the length of the inner MAC header.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
+ * Description
+ * Redirect the packet to the endpoint referenced by *map* at
+ * index *key*. Depending on its type, this *map* can contain
+ * references to net devices (for forwarding packets through other
+ * ports), or to CPUs (for redirecting XDP frames to another CPU;
+ * but this is only implemented for native XDP (with driver
+ * support) as of this writing).
+ *
+ * The lower two bits of *flags* are used as the return code if
+ * the map lookup fails. This is so that the return value can be
+ * one of the XDP program return codes up to **XDP_TX**, as chosen
+ * by the caller. Any higher bits in the *flags* argument must be
+ * unset.
+ *
+ * See also **bpf_redirect**\ (), which only supports redirecting
+ * to an ifindex, but doesn't require a map to do so.
+ * Return
+ * **XDP_REDIRECT** on success, or the value of the two lower bits
+ * of the *flags* argument on error.
+ *
+ * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
+ * Description
+ * Redirect the packet to the socket referenced by *map* (of type
+ * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
+ * egress interfaces can be used for redirection. The
+ * **BPF_F_INGRESS** value in *flags* is used to make the
+ * distinction (ingress path is selected if the flag is present,
+ * egress path otherwise). This is the only flag supported for now.
+ * Return
+ * **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
+ * Description
+ * Add an entry to, or update a *map* referencing sockets. The
+ * *skops* is used as a new value for the entry associated to
+ * *key*. *flags* is one of:
+ *
+ * **BPF_NOEXIST**
+ * The entry for *key* must not exist in the map.
+ * **BPF_EXIST**
+ * The entry for *key* must already exist in the map.
+ * **BPF_ANY**
+ * No condition on the existence of the entry for *key*.
+ *
+ * If the *map* has eBPF programs (parser and verdict), those will
+ * be inherited by the socket being added. If the socket is
+ * already attached to eBPF programs, this results in an error.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
+ * Description
+ * Adjust the address pointed by *xdp_md*\ **->data_meta** by
+ * *delta* (which can be positive or negative). Note that this
+ * operation modifies the address stored in *xdp_md*\ **->data**,
+ * so the latter must be loaded only after the helper has been
+ * called.
+ *
+ * The use of *xdp_md*\ **->data_meta** is optional and programs
+ * are not required to use it. The rationale is that when the
+ * packet is processed with XDP (e.g. as DoS filter), it is
+ * possible to push further meta data along with it before passing
+ * to the stack, and to give the guarantee that an ingress eBPF
+ * program attached as a TC classifier on the same device can pick
+ * this up for further post-processing. Since TC works with socket
+ * buffers, it remains possible to set from XDP the **mark** or
+ * **priority** pointers, or other pointers for the socket buffer.
+ * Having this scratch space generic and programmable allows for
+ * more flexibility as the user is free to store whatever meta
+ * data they need.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
+ * Description
+ * Read the value of a perf event counter, and store it into *buf*
+ * of size *buf_size*. This helper relies on a *map* of type
+ * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
+ * counter is selected when *map* is updated with perf event file
+ * descriptors. The *map* is an array whose size is the number of
+ * available CPUs, and each cell contains a value relative to one
+ * CPU. The value to retrieve is indicated by *flags*, that
+ * contains the index of the CPU to look up, masked with
+ * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
+ * **BPF_F_CURRENT_CPU** to indicate that the value for the
+ * current CPU should be retrieved.
+ *
+ * This helper behaves in a way close to
+ * **bpf_perf_event_read**\ () helper, save that instead of
+ * just returning the value observed, it fills the *buf*
+ * structure. This allows for additional data to be retrieved: in
+ * particular, the enabled and running times (in *buf*\
+ * **->enabled** and *buf*\ **->running**, respectively) are
+ * copied. In general, **bpf_perf_event_read_value**\ () is
+ * recommended over **bpf_perf_event_read**\ (), which has some
+ * ABI issues and provides fewer functionalities.
+ *
+ * These values are interesting, because hardware PMU (Performance
+ * Monitoring Unit) counters are limited resources. When there are
+ * more PMU based perf events opened than available counters,
+ * kernel will multiplex these events so each event gets certain
+ * percentage (but not all) of the PMU time. In case that
+ * multiplexing happens, the number of samples or counter value
+ * will not reflect the case compared to when no multiplexing
+ * occurs. This makes comparison between different runs difficult.
+ * Typically, the counter value should be normalized before
+ * comparing to other experiments. The usual normalization is done
+ * as follows.
+ *
+ * ::
+ *
+ * normalized_counter = counter * t_enabled / t_running
+ *
+ * Where t_enabled is the time enabled for event and t_running is
+ * the time running for event since last normalization. The
+ * enabled and running times are accumulated since the perf event
+ * open. To achieve scaling factor between two invocations of an
+ * eBPF program, users can use CPU id as the key (which is
+ * typical for perf array usage model) to remember the previous
+ * value and do the calculation inside the eBPF program.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
+ * Description
+ * For en eBPF program attached to a perf event, retrieve the
+ * value of the event counter associated to *ctx* and store it in
+ * the structure pointed by *buf* and of size *buf_size*. Enabled
+ * and running times are also stored in the structure (see
+ * description of helper **bpf_perf_event_read_value**\ () for
+ * more details).
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
+ * Description
+ * Emulate a call to **getsockopt()** on the socket associated to
+ * *bpf_socket*, which must be a full socket. The *level* at
+ * which the option resides and the name *optname* of the option
+ * must be specified, see **getsockopt(2)** for more information.
+ * The retrieved value is stored in the structure pointed by
+ * *opval* and of length *optlen*.
+ *
+ * *bpf_socket* should be one of the following:
+ *
+ * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
+ * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
+ * and **BPF_CGROUP_INET6_CONNECT**.
+ *
+ * This helper actually implements a subset of **getsockopt()**.
+ * It supports the following *level*\ s:
+ *
+ * * **IPPROTO_TCP**, which supports *optname*
+ * **TCP_CONGESTION**.
+ * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
+ * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_override_return(struct pt_regs *regs, u64 rc)
+ * Description
+ * Used for error injection, this helper uses kprobes to override
+ * the return value of the probed function, and to set it to *rc*.
+ * The first argument is the context *regs* on which the kprobe
+ * works.
+ *
+ * This helper works by setting the PC (program counter)
+ * to an override function which is run in place of the original
+ * probed function. This means the probed function is not run at
+ * all. The replacement function just returns with the required
+ * value.
+ *
+ * This helper has security implications, and thus is subject to
+ * restrictions. It is only available if the kernel was compiled
+ * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
+ * option, and in this case it only works on functions tagged with
+ * **ALLOW_ERROR_INJECTION** in the kernel code.
+ *
+ * Also, the helper is only available for the architectures having
+ * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
+ * x86 architecture is the only one to support this feature.
+ * Return
+ * 0
+ *
+ * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
+ * Description
+ * Attempt to set the value of the **bpf_sock_ops_cb_flags** field
+ * for the full TCP socket associated to *bpf_sock_ops* to
+ * *argval*.
+ *
+ * The primary use of this field is to determine if there should
+ * be calls to eBPF programs of type
+ * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
+ * code. A program of the same type can change its value, per
+ * connection and as necessary, when the connection is
+ * established. This field is directly accessible for reading, but
+ * this helper must be used for updates in order to return an
+ * error if an eBPF program tries to set a callback that is not
+ * supported in the current kernel.
+ *
+ * *argval* is a flag array which can combine these flags:
+ *
+ * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
+ * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
+ * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
+ * * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
+ *
+ * Therefore, this function can be used to clear a callback flag by
+ * setting the appropriate bit to zero. e.g. to disable the RTO
+ * callback:
+ *
+ * **bpf_sock_ops_cb_flags_set(bpf_sock,**
+ * **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
+ *
+ * Here are some examples of where one could call such eBPF
+ * program:
+ *
+ * * When RTO fires.
+ * * When a packet is retransmitted.
+ * * When the connection terminates.
+ * * When a packet is sent.
+ * * When a packet is received.
+ * Return
+ * Code **-EINVAL** if the socket is not a full TCP socket;
+ * otherwise, a positive number containing the bits that could not
+ * be set is returned (which comes down to 0 if all bits were set
+ * as required).
+ *
+ * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
+ * Description
+ * This helper is used in programs implementing policies at the
+ * socket level. If the message *msg* is allowed to pass (i.e. if
+ * the verdict eBPF program returns **SK_PASS**), redirect it to
+ * the socket referenced by *map* (of type
+ * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
+ * egress interfaces can be used for redirection. The
+ * **BPF_F_INGRESS** value in *flags* is used to make the
+ * distinction (ingress path is selected if the flag is present,
+ * egress path otherwise). This is the only flag supported for now.
+ * Return
+ * **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
+ * Description
+ * For socket policies, apply the verdict of the eBPF program to
+ * the next *bytes* (number of bytes) of message *msg*.
+ *
+ * For example, this helper can be used in the following cases:
+ *
+ * * A single **sendmsg**\ () or **sendfile**\ () system call
+ * contains multiple logical messages that the eBPF program is
+ * supposed to read and for which it should apply a verdict.
+ * * An eBPF program only cares to read the first *bytes* of a
+ * *msg*. If the message has a large payload, then setting up
+ * and calling the eBPF program repeatedly for all bytes, even
+ * though the verdict is already known, would create unnecessary
+ * overhead.
+ *
+ * When called from within an eBPF program, the helper sets a
+ * counter internal to the BPF infrastructure, that is used to
+ * apply the last verdict to the next *bytes*. If *bytes* is
+ * smaller than the current data being processed from a
+ * **sendmsg**\ () or **sendfile**\ () system call, the first
+ * *bytes* will be sent and the eBPF program will be re-run with
+ * the pointer for start of data pointing to byte number *bytes*
+ * **+ 1**. If *bytes* is larger than the current data being
+ * processed, then the eBPF verdict will be applied to multiple
+ * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
+ * consumed.
+ *
+ * Note that if a socket closes with the internal counter holding
+ * a non-zero value, this is not a problem because data is not
+ * being buffered for *bytes* and is sent as it is received.
+ * Return
+ * 0
+ *
+ * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
+ * Description
+ * For socket policies, prevent the execution of the verdict eBPF
+ * program for message *msg* until *bytes* (byte number) have been
+ * accumulated.
+ *
+ * This can be used when one needs a specific number of bytes
+ * before a verdict can be assigned, even if the data spans
+ * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
+ * case would be a user calling **sendmsg**\ () repeatedly with
+ * 1-byte long message segments. Obviously, this is bad for
+ * performance, but it is still valid. If the eBPF program needs
+ * *bytes* bytes to validate a header, this helper can be used to
+ * prevent the eBPF program to be called again until *bytes* have
+ * been accumulated.
+ * Return
+ * 0
+ *
+ * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
+ * Description
+ * For socket policies, pull in non-linear data from user space
+ * for *msg* and set pointers *msg*\ **->data** and *msg*\
+ * **->data_end** to *start* and *end* bytes offsets into *msg*,
+ * respectively.
+ *
+ * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ * *msg* it can only parse data that the (**data**, **data_end**)
+ * pointers have already consumed. For **sendmsg**\ () hooks this
+ * is likely the first scatterlist element. But for calls relying
+ * on the **sendpage** handler (e.g. **sendfile**\ ()) this will
+ * be the range (**0**, **0**) because the data is shared with
+ * user space and by default the objective is to avoid allowing
+ * user space to modify data while (or after) eBPF verdict is
+ * being decided. This helper can be used to pull in data and to
+ * set the start and end pointer to given values. Data will be
+ * copied if necessary (i.e. if data was not linear and if start
+ * and end pointers do not point to the same chunk).
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
+ * Description
+ * Bind the socket associated to *ctx* to the address pointed by
+ * *addr*, of length *addr_len*. This allows for making outgoing
+ * connection from the desired IP address, which can be useful for
+ * example when all processes inside a cgroup should use one
+ * single IP address on a host that has multiple IP configured.
+ *
+ * This helper works for IPv4 and IPv6, TCP and UDP sockets. The
+ * domain (*addr*\ **->sa_family**) must be **AF_INET** (or
+ * **AF_INET6**). It's advised to pass zero port (**sin_port**
+ * or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
+ * behavior and lets the kernel efficiently pick up an unused
+ * port as long as 4-tuple is unique. Passing non-zero port might
+ * lead to degraded performance.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
+ * Description
+ * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
+ * possible to both shrink and grow the packet tail.
+ * Shrink done via *delta* being a negative integer.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
+ * Description
+ * Retrieve the XFRM state (IP transform framework, see also
+ * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
+ *
+ * The retrieved value is stored in the **struct bpf_xfrm_state**
+ * pointed by *xfrm_state* and of length *size*.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * This helper is available only if the kernel was compiled with
+ * **CONFIG_XFRM** configuration option.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
+ * Description
+ * Return a user or a kernel stack in bpf program provided buffer.
+ * To achieve this, the helper needs *ctx*, which is a pointer
+ * to the context on which the tracing program is executed.
+ * To store the stacktrace, the bpf program provides *buf* with
+ * a nonnegative *size*.
+ *
+ * The last argument, *flags*, holds the number of stack frames to
+ * skip (from 0 to 255), masked with
+ * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * the following flags:
+ *
+ * **BPF_F_USER_STACK**
+ * Collect a user space stack instead of a kernel stack.
+ * **BPF_F_USER_BUILD_ID**
+ * Collect buildid+offset instead of ips for user stack,
+ * only valid if **BPF_F_USER_STACK** is also specified.
+ *
+ * **bpf_get_stack**\ () can collect up to
+ * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
+ * to sufficient large buffer size. Note that
+ * this limit can be controlled with the **sysctl** program, and
+ * that it should be manually increased in order to profile long
+ * user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * ::
+ *
+ * # sysctl kernel.perf_event_max_stack=<new value>
+ * Return
+ * A non-negative value equal to or less than *size* on success,
+ * or a negative error in case of failure.
+ *
+ * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
+ * Description
+ * This helper is similar to **bpf_skb_load_bytes**\ () in that
+ * it provides an easy way to load *len* bytes from *offset*
+ * from the packet associated to *skb*, into the buffer pointed
+ * by *to*. The difference to **bpf_skb_load_bytes**\ () is that
+ * a fifth argument *start_header* exists in order to select a
+ * base offset to start from. *start_header* can be one of:
+ *
+ * **BPF_HDR_START_MAC**
+ * Base offset to load data from is *skb*'s mac header.
+ * **BPF_HDR_START_NET**
+ * Base offset to load data from is *skb*'s network header.
+ *
+ * In general, "direct packet access" is the preferred method to
+ * access packet data, however, this helper is in particular useful
+ * in socket filters where *skb*\ **->data** does not always point
+ * to the start of the mac header and where "direct packet access"
+ * is not available.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
+ * Description
+ * Do FIB lookup in kernel tables using parameters in *params*.
+ * If lookup is successful and result shows packet is to be
+ * forwarded, the neighbor tables are searched for the nexthop.
+ * If successful (ie., FIB lookup shows forwarding and nexthop
+ * is resolved), the nexthop address is returned in ipv4_dst
+ * or ipv6_dst based on family, smac is set to mac address of
+ * egress device, dmac is set to nexthop mac address, rt_metric
+ * is set to metric from route (IPv4/IPv6 only), and ifindex
+ * is set to the device index of the nexthop from the FIB lookup.
+ *
+ * *plen* argument is the size of the passed in struct.
+ * *flags* argument can be a combination of one or more of the
+ * following values:
+ *
+ * **BPF_FIB_LOOKUP_DIRECT**
+ * Do a direct table lookup vs full lookup using FIB
+ * rules.
+ * **BPF_FIB_LOOKUP_OUTPUT**
+ * Perform lookup from an egress perspective (default is
+ * ingress).
+ *
+ * *ctx* is either **struct xdp_md** for XDP programs or
+ * **struct sk_buff** tc cls_act programs.
+ * Return
+ * * < 0 if any input argument is invalid
+ * * 0 on success (packet is forwarded, nexthop neighbor exists)
+ * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
+ * packet is not forwarded or needs assist from full stack
+ *
+ * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
+ * Description
+ * Add an entry to, or update a sockhash *map* referencing sockets.
+ * The *skops* is used as a new value for the entry associated to
+ * *key*. *flags* is one of:
+ *
+ * **BPF_NOEXIST**
+ * The entry for *key* must not exist in the map.
+ * **BPF_EXIST**
+ * The entry for *key* must already exist in the map.
+ * **BPF_ANY**
+ * No condition on the existence of the entry for *key*.
+ *
+ * If the *map* has eBPF programs (parser and verdict), those will
+ * be inherited by the socket being added. If the socket is
+ * already attached to eBPF programs, this results in an error.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
+ * Description
+ * This helper is used in programs implementing policies at the
+ * socket level. If the message *msg* is allowed to pass (i.e. if
+ * the verdict eBPF program returns **SK_PASS**), redirect it to
+ * the socket referenced by *map* (of type
+ * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
+ * egress interfaces can be used for redirection. The
+ * **BPF_F_INGRESS** value in *flags* is used to make the
+ * distinction (ingress path is selected if the flag is present,
+ * egress path otherwise). This is the only flag supported for now.
+ * Return
+ * **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
+ * Description
+ * This helper is used in programs implementing policies at the
+ * skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
+ * if the verdict eBPF program returns **SK_PASS**), redirect it
+ * to the socket referenced by *map* (of type
+ * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
+ * egress interfaces can be used for redirection. The
+ * **BPF_F_INGRESS** value in *flags* is used to make the
+ * distinction (ingress path is selected if the flag is present,
+ * egress otherwise). This is the only flag supported for now.
+ * Return
+ * **SK_PASS** on success, or **SK_DROP** on error.
+ *
+ * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
+ * Description
+ * Encapsulate the packet associated to *skb* within a Layer 3
+ * protocol header. This header is provided in the buffer at
+ * address *hdr*, with *len* its size in bytes. *type* indicates
+ * the protocol of the header and can be one of:
+ *
+ * **BPF_LWT_ENCAP_SEG6**
+ * IPv6 encapsulation with Segment Routing Header
+ * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
+ * the IPv6 header is computed by the kernel.
+ * **BPF_LWT_ENCAP_SEG6_INLINE**
+ * Only works if *skb* contains an IPv6 packet. Insert a
+ * Segment Routing Header (**struct ipv6_sr_hdr**) inside
+ * the IPv6 header.
+ * **BPF_LWT_ENCAP_IP**
+ * IP encapsulation (GRE/GUE/IPIP/etc). The outer header
+ * must be IPv4 or IPv6, followed by zero or more
+ * additional headers, up to **LWT_BPF_MAX_HEADROOM**
+ * total bytes in all prepended headers. Please note that
+ * if **skb_is_gso**\ (*skb*) is true, no more than two
+ * headers can be prepended, and the inner header, if
+ * present, should be either GRE or UDP/GUE.
+ *
+ * **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
+ * of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
+ * be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
+ * **BPF_PROG_TYPE_LWT_XMIT**.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
+ * Description
+ * Store *len* bytes from address *from* into the packet
+ * associated to *skb*, at *offset*. Only the flags, tag and TLVs
+ * inside the outermost IPv6 Segment Routing Header can be
+ * modified through this helper.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
+ * Description
+ * Adjust the size allocated to TLVs in the outermost IPv6
+ * Segment Routing Header contained in the packet associated to
+ * *skb*, at position *offset* by *delta* bytes. Only offsets
+ * after the segments are accepted. *delta* can be as well
+ * positive (growing) as negative (shrinking).
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
+ * Description
+ * Apply an IPv6 Segment Routing action of type *action* to the
+ * packet associated to *skb*. Each action takes a parameter
+ * contained at address *param*, and of length *param_len* bytes.
+ * *action* can be one of:
+ *
+ * **SEG6_LOCAL_ACTION_END_X**
+ * End.X action: Endpoint with Layer-3 cross-connect.
+ * Type of *param*: **struct in6_addr**.
+ * **SEG6_LOCAL_ACTION_END_T**
+ * End.T action: Endpoint with specific IPv6 table lookup.
+ * Type of *param*: **int**.
+ * **SEG6_LOCAL_ACTION_END_B6**
+ * End.B6 action: Endpoint bound to an SRv6 policy.
+ * Type of *param*: **struct ipv6_sr_hdr**.
+ * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
+ * End.B6.Encap action: Endpoint bound to an SRv6
+ * encapsulation policy.
+ * Type of *param*: **struct ipv6_sr_hdr**.
+ *
+ * A call to this helper is susceptible to change the underlying
+ * packet buffer. Therefore, at load time, all checks on pointers
+ * previously done by the verifier are invalidated and must be
+ * performed again, if the helper is used in combination with
+ * direct packet access.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_rc_repeat(void *ctx)
+ * Description
+ * This helper is used in programs implementing IR decoding, to
+ * report a successfully decoded repeat key message. This delays
+ * the generation of a key up event for previously generated
+ * key down event.
+ *
+ * Some IR protocols like NEC have a special IR message for
+ * repeating last button, for when a button is held down.
+ *
+ * The *ctx* should point to the lirc sample as passed into
+ * the program.
+ *
+ * This helper is only available is the kernel was compiled with
+ * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * "**y**".
+ * Return
+ * 0
+ *
+ * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
+ * Description
+ * This helper is used in programs implementing IR decoding, to
+ * report a successfully decoded key press with *scancode*,
+ * *toggle* value in the given *protocol*. The scancode will be
+ * translated to a keycode using the rc keymap, and reported as
+ * an input key down event. After a period a key up event is
+ * generated. This period can be extended by calling either
+ * **bpf_rc_keydown**\ () again with the same values, or calling
+ * **bpf_rc_repeat**\ ().
+ *
+ * Some protocols include a toggle bit, in case the button was
+ * released and pressed again between consecutive scancodes.
+ *
+ * The *ctx* should point to the lirc sample as passed into
+ * the program.
+ *
+ * The *protocol* is the decoded protocol number (see
+ * **enum rc_proto** for some predefined values).
+ *
+ * This helper is only available is the kernel was compiled with
+ * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * "**y**".
+ * Return
+ * 0
+ *
+ * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
+ * Description
+ * Return the cgroup v2 id of the socket associated with the *skb*.
+ * This is roughly similar to the **bpf_get_cgroup_classid**\ ()
+ * helper for cgroup v1 by providing a tag resp. identifier that
+ * can be matched on or used for map lookups e.g. to implement
+ * policy. The cgroup v2 id of a given path in the hierarchy is
+ * exposed in user space through the f_handle API in order to get
+ * to the same 64-bit id.
+ *
+ * This helper can be used on TC egress path, but not on ingress,
+ * and is available only if the kernel was compiled with the
+ * **CONFIG_SOCK_CGROUP_DATA** configuration option.
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * u64 bpf_get_current_cgroup_id(void)
+ * Return
+ * A 64-bit integer containing the current cgroup id based
+ * on the cgroup within which the current task is running.
+ *
+ * void *bpf_get_local_storage(void *map, u64 flags)
+ * Description
+ * Get the pointer to the local storage area.
+ * The type and the size of the local storage is defined
+ * by the *map* argument.
+ * The *flags* meaning is specific for each map type,
+ * and has to be 0 for cgroup local storage.
+ *
+ * Depending on the BPF program type, a local storage area
+ * can be shared between multiple instances of the BPF program,
+ * running simultaneously.
+ *
+ * A user should care about the synchronization by himself.
+ * For example, by using the **BPF_STX_XADD** instruction to alter
+ * the shared data.
+ * Return
+ * A pointer to the local storage area.
+ *
+ * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
+ * Description
+ * Select a **SO_REUSEPORT** socket from a
+ * **BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
+ * It checks the selected socket is matching the incoming
+ * request in the socket buffer.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
+ * Description
+ * Return id of cgroup v2 that is ancestor of cgroup associated
+ * with the *skb* at the *ancestor_level*. The root cgroup is at
+ * *ancestor_level* zero and each step down the hierarchy
+ * increments the level. If *ancestor_level* == level of cgroup
+ * associated with *skb*, then return value will be same as that
+ * of **bpf_skb_cgroup_id**\ ().
+ *
+ * The helper is useful to implement policies based on cgroups
+ * that are upper in hierarchy than immediate cgroup associated
+ * with *skb*.
+ *
+ * The format of returned id and helper limitations are same as in
+ * **bpf_skb_cgroup_id**\ ().
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
+ * Description
+ * Look for TCP socket matching *tuple*, optionally in a child
+ * network namespace *netns*. The return value must be checked,
+ * and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * The *ctx* should point to the context of the program, such as
+ * the skb or socket (depending on the hook in use). This is used
+ * to determine the base network namespace for the lookup.
+ *
+ * *tuple_size* must be one of:
+ *
+ * **sizeof**\ (*tuple*\ **->ipv4**)
+ * Look for an IPv4 socket.
+ * **sizeof**\ (*tuple*\ **->ipv6**)
+ * Look for an IPv6 socket.
+ *
+ * If the *netns* is a negative signed 32-bit integer, then the
+ * socket lookup table in the netns associated with the *ctx*
+ * will be used. For the TC hooks, this is the netns of the device
+ * in the skb. For socket hooks, this is the netns of the socket.
+ * If *netns* is any other signed 32-bit value greater than or
+ * equal to zero then it specifies the ID of the netns relative to
+ * the netns associated with the *ctx*. *netns* values beyond the
+ * range of 32-bit integers are reserved for future use.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * This helper is available only if the kernel was compiled with
+ * **CONFIG_NET** configuration option.
+ * Return
+ * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * For sockets with reuseport option, the **struct bpf_sock**
+ * result is from *reuse*\ **->socks**\ [] using the hash of the
+ * tuple.
+ *
+ * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
+ * Description
+ * Look for UDP socket matching *tuple*, optionally in a child
+ * network namespace *netns*. The return value must be checked,
+ * and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * The *ctx* should point to the context of the program, such as
+ * the skb or socket (depending on the hook in use). This is used
+ * to determine the base network namespace for the lookup.
+ *
+ * *tuple_size* must be one of:
+ *
+ * **sizeof**\ (*tuple*\ **->ipv4**)
+ * Look for an IPv4 socket.
+ * **sizeof**\ (*tuple*\ **->ipv6**)
+ * Look for an IPv6 socket.
+ *
+ * If the *netns* is a negative signed 32-bit integer, then the
+ * socket lookup table in the netns associated with the *ctx*
+ * will be used. For the TC hooks, this is the netns of the device
+ * in the skb. For socket hooks, this is the netns of the socket.
+ * If *netns* is any other signed 32-bit value greater than or
+ * equal to zero then it specifies the ID of the netns relative to
+ * the netns associated with the *ctx*. *netns* values beyond the
+ * range of 32-bit integers are reserved for future use.
+ *
+ * All values for *flags* are reserved for future usage, and must
+ * be left at zero.
+ *
+ * This helper is available only if the kernel was compiled with
+ * **CONFIG_NET** configuration option.
+ * Return
+ * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * For sockets with reuseport option, the **struct bpf_sock**
+ * result is from *reuse*\ **->socks**\ [] using the hash of the
+ * tuple.
+ *
+ * long bpf_sk_release(void *sock)
+ * Description
+ * Release the reference held by *sock*. *sock* must be a
+ * non-**NULL** pointer that was returned from
+ * **bpf_sk_lookup_xxx**\ ().
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
+ * Description
+ * Push an element *value* in *map*. *flags* is one of:
+ *
+ * **BPF_EXIST**
+ * If the queue/stack is full, the oldest element is
+ * removed to make room for this.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_map_pop_elem(struct bpf_map *map, void *value)
+ * Description
+ * Pop an element from *map*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_map_peek_elem(struct bpf_map *map, void *value)
+ * Description
+ * Get an element from *map* without removing it.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
+ * Description
+ * For socket policies, insert *len* bytes into *msg* at offset
+ * *start*.
+ *
+ * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
+ * *msg* it may want to insert metadata or options into the *msg*.
+ * This can later be read and used by any of the lower layer BPF
+ * hooks.
+ *
+ * This helper may fail if under memory pressure (a malloc
+ * fails) in these cases BPF programs will get an appropriate
+ * error and BPF programs will need to handle them.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
+ * Description
+ * Will remove *len* bytes from a *msg* starting at byte *start*.
+ * This may result in **ENOMEM** errors under certain situations if
+ * an allocation and copy are required due to a full ring buffer.
+ * However, the helper will try to avoid doing the allocation
+ * if possible. Other errors can occur if input parameters are
+ * invalid either due to *start* byte not being valid part of *msg*
+ * payload and/or *pop* value being to large.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
+ * Description
+ * This helper is used in programs implementing IR decoding, to
+ * report a successfully decoded pointer movement.
+ *
+ * The *ctx* should point to the lirc sample as passed into
+ * the program.
+ *
+ * This helper is only available is the kernel was compiled with
+ * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
+ * "**y**".
+ * Return
+ * 0
+ *
+ * long bpf_spin_lock(struct bpf_spin_lock *lock)
+ * Description
+ * Acquire a spinlock represented by the pointer *lock*, which is
+ * stored as part of a value of a map. Taking the lock allows to
+ * safely update the rest of the fields in that value. The
+ * spinlock can (and must) later be released with a call to
+ * **bpf_spin_unlock**\ (\ *lock*\ ).
+ *
+ * Spinlocks in BPF programs come with a number of restrictions
+ * and constraints:
+ *
+ * * **bpf_spin_lock** objects are only allowed inside maps of
+ * types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
+ * list could be extended in the future).
+ * * BTF description of the map is mandatory.
+ * * The BPF program can take ONE lock at a time, since taking two
+ * or more could cause dead locks.
+ * * Only one **struct bpf_spin_lock** is allowed per map element.
+ * * When the lock is taken, calls (either BPF to BPF or helpers)
+ * are not allowed.
+ * * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
+ * allowed inside a spinlock-ed region.
+ * * The BPF program MUST call **bpf_spin_unlock**\ () to release
+ * the lock, on all execution paths, before it returns.
+ * * The BPF program can access **struct bpf_spin_lock** only via
+ * the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
+ * helpers. Loading or storing data into the **struct
+ * bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
+ * * To use the **bpf_spin_lock**\ () helper, the BTF description
+ * of the map value must be a struct and have **struct
+ * bpf_spin_lock** *anyname*\ **;** field at the top level.
+ * Nested lock inside another struct is not allowed.
+ * * The **struct bpf_spin_lock** *lock* field in a map value must
+ * be aligned on a multiple of 4 bytes in that value.
+ * * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
+ * the **bpf_spin_lock** field to user space.
+ * * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
+ * a BPF program, do not update the **bpf_spin_lock** field.
+ * * **bpf_spin_lock** cannot be on the stack or inside a
+ * networking packet (it can only be inside of a map values).
+ * * **bpf_spin_lock** is available to root only.
+ * * Tracing programs and socket filter programs cannot use
+ * **bpf_spin_lock**\ () due to insufficient preemption checks
+ * (but this may change in the future).
+ * * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
+ * Return
+ * 0
+ *
+ * long bpf_spin_unlock(struct bpf_spin_lock *lock)
+ * Description
+ * Release the *lock* previously locked by a call to
+ * **bpf_spin_lock**\ (\ *lock*\ ).
+ * Return
+ * 0
+ *
+ * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
+ * Description
+ * This helper gets a **struct bpf_sock** pointer such
+ * that all the fields in this **bpf_sock** can be accessed.
+ * Return
+ * A **struct bpf_sock** pointer on success, or **NULL** in
+ * case of failure.
+ *
+ * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
+ * Description
+ * This helper gets a **struct bpf_tcp_sock** pointer from a
+ * **struct bpf_sock** pointer.
+ * Return
+ * A **struct bpf_tcp_sock** pointer on success, or **NULL** in
+ * case of failure.
+ *
+ * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
+ * Description
+ * Set ECN (Explicit Congestion Notification) field of IP header
+ * to **CE** (Congestion Encountered) if current value is **ECT**
+ * (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
+ * and IPv4.
+ * Return
+ * 1 if the **CE** flag is set (either by the current helper call
+ * or because it was already present), 0 if it is not set.
+ *
+ * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
+ * Description
+ * Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
+ * **bpf_sk_release**\ () is unnecessary and not allowed.
+ * Return
+ * A **struct bpf_sock** pointer on success, or **NULL** in
+ * case of failure.
+ *
+ * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
+ * Description
+ * Look for TCP socket matching *tuple*, optionally in a child
+ * network namespace *netns*. The return value must be checked,
+ * and if non-**NULL**, released via **bpf_sk_release**\ ().
+ *
+ * This function is identical to **bpf_sk_lookup_tcp**\ (), except
+ * that it also returns timewait or request sockets. Use
+ * **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
+ * full structure.
+ *
+ * This helper is available only if the kernel was compiled with
+ * **CONFIG_NET** configuration option.
+ * Return
+ * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
+ * For sockets with reuseport option, the **struct bpf_sock**
+ * result is from *reuse*\ **->socks**\ [] using the hash of the
+ * tuple.
+ *
+ * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
+ * Description
+ * Check whether *iph* and *th* contain a valid SYN cookie ACK for
+ * the listening socket in *sk*.
+ *
+ * *iph* points to the start of the IPv4 or IPv6 header, while
+ * *iph_len* contains **sizeof**\ (**struct iphdr**) or
+ * **sizeof**\ (**struct ip6hdr**).
+ *
+ * *th* points to the start of the TCP header, while *th_len*
+ * contains **sizeof**\ (**struct tcphdr**).
+ * Return
+ * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
+ * error otherwise.
+ *
+ * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
+ * Description
+ * Get name of sysctl in /proc/sys/ and copy it into provided by
+ * program buffer *buf* of size *buf_len*.
+ *
+ * The buffer is always NUL terminated, unless it's zero-sized.
+ *
+ * If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
+ * copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
+ * only (e.g. "tcp_mem").
+ * Return
+ * Number of character copied (not including the trailing NUL).
+ *
+ * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * truncated name in this case).
+ *
+ * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
+ * Description
+ * Get current value of sysctl as it is presented in /proc/sys
+ * (incl. newline, etc), and copy it as a string into provided
+ * by program buffer *buf* of size *buf_len*.
+ *
+ * The whole value is copied, no matter what file position user
+ * space issued e.g. sys_read at.
+ *
+ * The buffer is always NUL terminated, unless it's zero-sized.
+ * Return
+ * Number of character copied (not including the trailing NUL).
+ *
+ * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * truncated name in this case).
+ *
+ * **-EINVAL** if current value was unavailable, e.g. because
+ * sysctl is uninitialized and read returns -EIO for it.
+ *
+ * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
+ * Description
+ * Get new value being written by user space to sysctl (before
+ * the actual write happens) and copy it as a string into
+ * provided by program buffer *buf* of size *buf_len*.
+ *
+ * User space may write new value at file position > 0.
+ *
+ * The buffer is always NUL terminated, unless it's zero-sized.
+ * Return
+ * Number of character copied (not including the trailing NUL).
+ *
+ * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
+ * truncated name in this case).
+ *
+ * **-EINVAL** if sysctl is being read.
+ *
+ * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
+ * Description
+ * Override new value being written by user space to sysctl with
+ * value provided by program in buffer *buf* of size *buf_len*.
+ *
+ * *buf* should contain a string in same form as provided by user
+ * space on sysctl write.
+ *
+ * User space may write new value at file position > 0. To override
+ * the whole sysctl value file position should be set to zero.
+ * Return
+ * 0 on success.
+ *
+ * **-E2BIG** if the *buf_len* is too big.
+ *
+ * **-EINVAL** if sysctl is being read.
+ *
+ * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
+ * Description
+ * Convert the initial part of the string from buffer *buf* of
+ * size *buf_len* to a long integer according to the given base
+ * and save the result in *res*.
+ *
+ * The string may begin with an arbitrary amount of white space
+ * (as determined by **isspace**\ (3)) followed by a single
+ * optional '**-**' sign.
+ *
+ * Five least significant bits of *flags* encode base, other bits
+ * are currently unused.
+ *
+ * Base must be either 8, 10, 16 or 0 to detect it automatically
+ * similar to user space **strtol**\ (3).
+ * Return
+ * Number of characters consumed on success. Must be positive but
+ * no more than *buf_len*.
+ *
+ * **-EINVAL** if no valid digits were found or unsupported base
+ * was provided.
+ *
+ * **-ERANGE** if resulting value was out of range.
+ *
+ * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
+ * Description
+ * Convert the initial part of the string from buffer *buf* of
+ * size *buf_len* to an unsigned long integer according to the
+ * given base and save the result in *res*.
+ *
+ * The string may begin with an arbitrary amount of white space
+ * (as determined by **isspace**\ (3)).
+ *
+ * Five least significant bits of *flags* encode base, other bits
+ * are currently unused.
+ *
+ * Base must be either 8, 10, 16 or 0 to detect it automatically
+ * similar to user space **strtoul**\ (3).
+ * Return
+ * Number of characters consumed on success. Must be positive but
+ * no more than *buf_len*.
+ *
+ * **-EINVAL** if no valid digits were found or unsupported base
+ * was provided.
+ *
+ * **-ERANGE** if resulting value was out of range.
+ *
+ * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
+ * Description
+ * Get a bpf-local-storage from a *sk*.
+ *
+ * Logically, it could be thought of getting the value from
+ * a *map* with *sk* as the **key**. From this
+ * perspective, the usage is not much different from
+ * **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
+ * helper enforces the key must be a full socket and the map must
+ * be a **BPF_MAP_TYPE_SK_STORAGE** also.
+ *
+ * Underneath, the value is stored locally at *sk* instead of
+ * the *map*. The *map* is used as the bpf-local-storage
+ * "type". The bpf-local-storage "type" (i.e. the *map*) is
+ * searched against all bpf-local-storages residing at *sk*.
+ *
+ * *sk* is a kernel **struct sock** pointer for LSM program.
+ * *sk* is a **struct bpf_sock** pointer for other program types.
+ *
+ * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
+ * used such that a new bpf-local-storage will be
+ * created if one does not exist. *value* can be used
+ * together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
+ * the initial value of a bpf-local-storage. If *value* is
+ * **NULL**, the new bpf-local-storage will be zero initialized.
+ * Return
+ * A bpf-local-storage pointer is returned on success.
+ *
+ * **NULL** if not found or there was an error in adding
+ * a new bpf-local-storage.
+ *
+ * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
+ * Description
+ * Delete a bpf-local-storage from a *sk*.
+ * Return
+ * 0 on success.
+ *
+ * **-ENOENT** if the bpf-local-storage cannot be found.
+ * **-EINVAL** if sk is not a fullsock (e.g. a request_sock).
+ *
+ * long bpf_send_signal(u32 sig)
+ * Description
+ * Send signal *sig* to the process of the current task.
+ * The signal may be delivered to any of this process's threads.
+ * Return
+ * 0 on success or successfully queued.
+ *
+ * **-EBUSY** if work queue under nmi is full.
+ *
+ * **-EINVAL** if *sig* is invalid.
+ *
+ * **-EPERM** if no permission to send the *sig*.
+ *
+ * **-EAGAIN** if bpf program can try again.
+ *
+ * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
+ * Description
+ * Try to issue a SYN cookie for the packet with corresponding
+ * IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
+ *
+ * *iph* points to the start of the IPv4 or IPv6 header, while
+ * *iph_len* contains **sizeof**\ (**struct iphdr**) or
+ * **sizeof**\ (**struct ip6hdr**).
+ *
+ * *th* points to the start of the TCP header, while *th_len*
+ * contains the length of the TCP header.
+ * Return
+ * On success, lower 32 bits hold the generated SYN cookie in
+ * followed by 16 bits which hold the MSS value for that cookie,
+ * and the top 16 bits are unused.
+ *
+ * On failure, the returned value is one of the following:
+ *
+ * **-EINVAL** SYN cookie cannot be issued due to error
+ *
+ * **-ENOENT** SYN cookie should not be issued (no SYN flood)
+ *
+ * **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
+ *
+ * **-EPROTONOSUPPORT** IP packet version is not 4 or 6
+ *
+ * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
+ * Description
+ * Write raw *data* blob into a special BPF perf event held by
+ * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * event must have the following attributes: **PERF_SAMPLE_RAW**
+ * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * The *flags* are used to indicate the index in *map* for which
+ * the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * to indicate that the index of the current CPU core should be
+ * used.
+ *
+ * The value to write, of *size*, is passed through eBPF stack and
+ * pointed by *data*.
+ *
+ * *ctx* is a pointer to in-kernel struct sk_buff.
+ *
+ * This helper is similar to **bpf_perf_event_output**\ () but
+ * restricted to raw_tracepoint bpf programs.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * Safely attempt to read *size* bytes from user space address
+ * *unsafe_ptr* and store the data in *dst*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * Safely attempt to read *size* bytes from kernel space address
+ * *unsafe_ptr* and store the data in *dst*.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * Copy a NUL terminated string from an unsafe user address
+ * *unsafe_ptr* to *dst*. The *size* should include the
+ * terminating NUL byte. In case the string length is smaller than
+ * *size*, the target is not padded with further NUL bytes. If the
+ * string length is larger than *size*, just *size*-1 bytes are
+ * copied and the last byte is set to NUL.
+ *
+ * On success, the length of the copied string is returned. This
+ * makes this helper useful in tracing programs for reading
+ * strings, and more importantly to get its length at runtime. See
+ * the following snippet:
+ *
+ * ::
+ *
+ * SEC("kprobe/sys_open")
+ * void bpf_sys_open(struct pt_regs *ctx)
+ * {
+ * char buf[PATHLEN]; // PATHLEN is defined to 256
+ * int res = bpf_probe_read_user_str(buf, sizeof(buf),
+ * ctx->di);
+ *
+ * // Consume buf, for example push it to
+ * // userspace via bpf_perf_event_output(); we
+ * // can use res (the string length) as event
+ * // size, after checking its boundaries.
+ * }
+ *
+ * In comparison, using **bpf_probe_read_user**\ () helper here
+ * instead to read the string would require to estimate the length
+ * at compile time, and would often result in copying more memory
+ * than necessary.
+ *
+ * Another useful use case is when parsing individual process
+ * arguments or individual environment variables navigating
+ * *current*\ **->mm->arg_start** and *current*\
+ * **->mm->env_start**: using this helper and the return value,
+ * one can quickly iterate at the right offset of the memory area.
+ * Return
+ * On success, the strictly positive length of the string,
+ * including the trailing NUL character. On error, a negative
+ * value.
+ *
+ * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
+ * Description
+ * Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
+ * to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
+ * Return
+ * On success, the strictly positive length of the string, including
+ * the trailing NUL character. On error, a negative value.
+ *
+ * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
+ * Description
+ * Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
+ * *rcv_nxt* is the ack_seq to be sent out.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_send_signal_thread(u32 sig)
+ * Description
+ * Send signal *sig* to the thread corresponding to the current task.
+ * Return
+ * 0 on success or successfully queued.
+ *
+ * **-EBUSY** if work queue under nmi is full.
+ *
+ * **-EINVAL** if *sig* is invalid.
+ *
+ * **-EPERM** if no permission to send the *sig*.
+ *
+ * **-EAGAIN** if bpf program can try again.
+ *
+ * u64 bpf_jiffies64(void)
+ * Description
+ * Obtain the 64bit jiffies
+ * Return
+ * The 64 bit jiffies
+ *
+ * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
+ * Description
+ * For an eBPF program attached to a perf event, retrieve the
+ * branch records (**struct perf_branch_entry**) associated to *ctx*
+ * and store it in the buffer pointed by *buf* up to size
+ * *size* bytes.
+ * Return
+ * On success, number of bytes written to *buf*. On error, a
+ * negative value.
+ *
+ * The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
+ * instead return the number of bytes required to store all the
+ * branch entries. If this flag is set, *buf* may be NULL.
+ *
+ * **-EINVAL** if arguments invalid or **size** not a multiple
+ * of **sizeof**\ (**struct perf_branch_entry**\ ).
+ *
+ * **-ENOENT** if architecture does not support branch records.
+ *
+ * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
+ * Description
+ * Returns 0 on success, values for *pid* and *tgid* as seen from the current
+ * *namespace* will be returned in *nsdata*.
+ * Return
+ * 0 on success, or one of the following in case of failure:
+ *
+ * **-EINVAL** if dev and inum supplied don't match dev_t and inode number
+ * with nsfs of current task, or if dev conversion to dev_t lost high bits.
+ *
+ * **-ENOENT** if pidns does not exists for the current task.
+ *
+ * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
+ * Description
+ * Write raw *data* blob into a special BPF perf event held by
+ * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
+ * event must have the following attributes: **PERF_SAMPLE_RAW**
+ * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
+ * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
+ *
+ * The *flags* are used to indicate the index in *map* for which
+ * the value must be put, masked with **BPF_F_INDEX_MASK**.
+ * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
+ * to indicate that the index of the current CPU core should be
+ * used.
+ *
+ * The value to write, of *size*, is passed through eBPF stack and
+ * pointed by *data*.
+ *
+ * *ctx* is a pointer to in-kernel struct xdp_buff.
+ *
+ * This helper is similar to **bpf_perf_eventoutput**\ () but
+ * restricted to raw_tracepoint bpf programs.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * u64 bpf_get_netns_cookie(void *ctx)
+ * Description
+ * Retrieve the cookie (generated by the kernel) of the network
+ * namespace the input *ctx* is associated with. The network
+ * namespace cookie remains stable for its lifetime and provides
+ * a global identifier that can be assumed unique. If *ctx* is
+ * NULL, then the helper returns the cookie for the initial
+ * network namespace. The cookie itself is very similar to that
+ * of **bpf_get_socket_cookie**\ () helper, but for network
+ * namespaces instead of sockets.
+ * Return
+ * A 8-byte long opaque number.
+ *
+ * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
+ * Description
+ * Return id of cgroup v2 that is ancestor of the cgroup associated
+ * with the current task at the *ancestor_level*. The root cgroup
+ * is at *ancestor_level* zero and each step down the hierarchy
+ * increments the level. If *ancestor_level* == level of cgroup
+ * associated with the current task, then return value will be the
+ * same as that of **bpf_get_current_cgroup_id**\ ().
+ *
+ * The helper is useful to implement policies based on cgroups
+ * that are upper in hierarchy than immediate cgroup associated
+ * with the current task.
+ *
+ * The format of returned id and helper limitations are same as in
+ * **bpf_get_current_cgroup_id**\ ().
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
+ * Description
+ * Helper is overloaded depending on BPF program type. This
+ * description applies to **BPF_PROG_TYPE_SCHED_CLS** and
+ * **BPF_PROG_TYPE_SCHED_ACT** programs.
+ *
+ * Assign the *sk* to the *skb*. When combined with appropriate
+ * routing configuration to receive the packet towards the socket,
+ * will cause *skb* to be delivered to the specified socket.
+ * Subsequent redirection of *skb* via **bpf_redirect**\ (),
+ * **bpf_clone_redirect**\ () or other methods outside of BPF may
+ * interfere with successful delivery to the socket.
+ *
+ * This operation is only valid from TC ingress path.
+ *
+ * The *flags* argument must be zero.
+ * Return
+ * 0 on success, or a negative error in case of failure:
+ *
+ * **-EINVAL** if specified *flags* are not supported.
+ *
+ * **-ENOENT** if the socket is unavailable for assignment.
+ *
+ * **-ENETUNREACH** if the socket is unreachable (wrong netns).
+ *
+ * **-EOPNOTSUPP** if the operation is not supported, for example
+ * a call from outside of TC ingress.
+ *
+ * **-ESOCKTNOSUPPORT** if the socket type is not supported
+ * (reuseport).
+ *
+ * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
+ * Description
+ * Helper is overloaded depending on BPF program type. This
+ * description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
+ *
+ * Select the *sk* as a result of a socket lookup.
+ *
+ * For the operation to succeed passed socket must be compatible
+ * with the packet description provided by the *ctx* object.
+ *
+ * L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
+ * be an exact match. While IP family (**AF_INET** or
+ * **AF_INET6**) must be compatible, that is IPv6 sockets
+ * that are not v6-only can be selected for IPv4 packets.
+ *
+ * Only TCP listeners and UDP unconnected sockets can be
+ * selected. *sk* can also be NULL to reset any previous
+ * selection.
+ *
+ * *flags* argument can combination of following values:
+ *
+ * * **BPF_SK_LOOKUP_F_REPLACE** to override the previous
+ * socket selection, potentially done by a BPF program
+ * that ran before us.
+ *
+ * * **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
+ * load-balancing within reuseport group for the socket
+ * being selected.
+ *
+ * On success *ctx->sk* will point to the selected socket.
+ *
+ * Return
+ * 0 on success, or a negative errno in case of failure.
+ *
+ * * **-EAFNOSUPPORT** if socket family (*sk->family*) is
+ * not compatible with packet family (*ctx->family*).
+ *
+ * * **-EEXIST** if socket has been already selected,
+ * potentially by another program, and
+ * **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
+ *
+ * * **-EINVAL** if unsupported flags were specified.
+ *
+ * * **-EPROTOTYPE** if socket L4 protocol
+ * (*sk->protocol*) doesn't match packet protocol
+ * (*ctx->protocol*).
+ *
+ * * **-ESOCKTNOSUPPORT** if socket is not in allowed
+ * state (TCP listening or UDP unconnected).
+ *
+ * u64 bpf_ktime_get_boot_ns(void)
+ * Description
+ * Return the time elapsed since system boot, in nanoseconds.
+ * Does include the time the system was suspended.
+ * See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
+ * Return
+ * Current *ktime*.
+ *
+ * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
+ * Description
+ * **bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
+ * out the format string.
+ * The *m* represents the seq_file. The *fmt* and *fmt_size* are for
+ * the format string itself. The *data* and *data_len* are format string
+ * arguments. The *data* are a **u64** array and corresponding format string
+ * values are stored in the array. For strings and pointers where pointees
+ * are accessed, only the pointer values are stored in the *data* array.
+ * The *data_len* is the size of *data* in bytes.
+ *
+ * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
+ * Reading kernel memory may fail due to either invalid address or
+ * valid address but requiring a major memory fault. If reading kernel memory
+ * fails, the string for **%s** will be an empty string, and the ip
+ * address for **%p{i,I}{4,6}** will be 0. Not returning error to
+ * bpf program is consistent with what **bpf_trace_printk**\ () does for now.
+ * Return
+ * 0 on success, or a negative error in case of failure:
+ *
+ * **-EBUSY** if per-CPU memory copy buffer is busy, can try again
+ * by returning 1 from bpf program.
+ *
+ * **-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
+ *
+ * **-E2BIG** if *fmt* contains too many format specifiers.
+ *
+ * **-EOVERFLOW** if an overflow happened: The same object will be tried again.
+ *
+ * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
+ * Description
+ * **bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
+ * The *m* represents the seq_file. The *data* and *len* represent the
+ * data to write in bytes.
+ * Return
+ * 0 on success, or a negative error in case of failure:
+ *
+ * **-EOVERFLOW** if an overflow happened: The same object will be tried again.
+ *
+ * u64 bpf_sk_cgroup_id(void *sk)
+ * Description
+ * Return the cgroup v2 id of the socket *sk*.
+ *
+ * *sk* must be a non-**NULL** pointer to a socket, e.g. one
+ * returned from **bpf_sk_lookup_xxx**\ (),
+ * **bpf_sk_fullsock**\ (), etc. The format of returned id is
+ * same as in **bpf_skb_cgroup_id**\ ().
+ *
+ * This helper is available only if the kernel was compiled with
+ * the **CONFIG_SOCK_CGROUP_DATA** configuration option.
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
+ * Description
+ * Return id of cgroup v2 that is ancestor of cgroup associated
+ * with the *sk* at the *ancestor_level*. The root cgroup is at
+ * *ancestor_level* zero and each step down the hierarchy
+ * increments the level. If *ancestor_level* == level of cgroup
+ * associated with *sk*, then return value will be same as that
+ * of **bpf_sk_cgroup_id**\ ().
+ *
+ * The helper is useful to implement policies based on cgroups
+ * that are upper in hierarchy than immediate cgroup associated
+ * with *sk*.
+ *
+ * The format of returned id and helper limitations are same as in
+ * **bpf_sk_cgroup_id**\ ().
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
+ * Description
+ * Copy *size* bytes from *data* into a ring buffer *ringbuf*.
+ * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * of new data availability is sent.
+ * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * of new data availability is sent unconditionally.
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
+ * Description
+ * Reserve *size* bytes of payload in a ring buffer *ringbuf*.
+ * Return
+ * Valid pointer with *size* bytes of memory available; NULL,
+ * otherwise.
+ *
+ * void bpf_ringbuf_submit(void *data, u64 flags)
+ * Description
+ * Submit reserved ring buffer sample, pointed to by *data*.
+ * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * of new data availability is sent.
+ * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * of new data availability is sent unconditionally.
+ * Return
+ * Nothing. Always succeeds.
+ *
+ * void bpf_ringbuf_discard(void *data, u64 flags)
+ * Description
+ * Discard reserved ring buffer sample, pointed to by *data*.
+ * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
+ * of new data availability is sent.
+ * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
+ * of new data availability is sent unconditionally.
+ * Return
+ * Nothing. Always succeeds.
+ *
+ * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
+ * Description
+ * Query various characteristics of provided ring buffer. What
+ * exactly is queries is determined by *flags*:
+ *
+ * * **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
+ * * **BPF_RB_RING_SIZE**: The size of ring buffer.
+ * * **BPF_RB_CONS_POS**: Consumer position (can wrap around).
+ * * **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
+ *
+ * Data returned is just a momentary snapshot of actual values
+ * and could be inaccurate, so this facility should be used to
+ * power heuristics and for reporting, not to make 100% correct
+ * calculation.
+ * Return
+ * Requested value, or 0, if *flags* are not recognized.
+ *
+ * long bpf_csum_level(struct sk_buff *skb, u64 level)
+ * Description
+ * Change the skbs checksum level by one layer up or down, or
+ * reset it entirely to none in order to have the stack perform
+ * checksum validation. The level is applicable to the following
+ * protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
+ * | ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
+ * through **bpf_skb_adjust_room**\ () helper with passing in
+ * **BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one call
+ * to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
+ * the UDP header is removed. Similarly, an encap of the latter
+ * into the former could be accompanied by a helper call to
+ * **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
+ * skb is still intended to be processed in higher layers of the
+ * stack instead of just egressing at tc.
+ *
+ * There are three supported level settings at this time:
+ *
+ * * **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
+ * with CHECKSUM_UNNECESSARY.
+ * * **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
+ * with CHECKSUM_UNNECESSARY.
+ * * **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
+ * sets CHECKSUM_NONE to force checksum validation by the stack.
+ * * **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
+ * skb->csum_level.
+ * Return
+ * 0 on success, or a negative error in case of failure. In the
+ * case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
+ * is returned or the error code -EACCES in case the skb is not
+ * subject to CHECKSUM_UNNECESSARY.
+ *
+ * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
+ *
+ * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
+ *
+ * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
+ *
+ * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
+ *
+ * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
+ * Description
+ * Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
+ * Return
+ * *sk* if casting is valid, or **NULL** otherwise.
+ *
+ * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
+ * Description
+ * Return a user or a kernel stack in bpf program provided buffer.
+ * To achieve this, the helper needs *task*, which is a valid
+ * pointer to **struct task_struct**. To store the stacktrace, the
+ * bpf program provides *buf* with a nonnegative *size*.
+ *
+ * The last argument, *flags*, holds the number of stack frames to
+ * skip (from 0 to 255), masked with
+ * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
+ * the following flags:
+ *
+ * **BPF_F_USER_STACK**
+ * Collect a user space stack instead of a kernel stack.
+ * **BPF_F_USER_BUILD_ID**
+ * Collect buildid+offset instead of ips for user stack,
+ * only valid if **BPF_F_USER_STACK** is also specified.
+ *
+ * **bpf_get_task_stack**\ () can collect up to
+ * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
+ * to sufficient large buffer size. Note that
+ * this limit can be controlled with the **sysctl** program, and
+ * that it should be manually increased in order to profile long
+ * user stacks (such as stacks for Java programs). To do so, use:
+ *
+ * ::
+ *
+ * # sysctl kernel.perf_event_max_stack=<new value>
+ * Return
+ * A non-negative value equal to or less than *size* on success,
+ * or a negative error in case of failure.
+ *
+ * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
+ * Description
+ * Load header option. Support reading a particular TCP header
+ * option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
+ *
+ * If *flags* is 0, it will search the option from the
+ * *skops*\ **->skb_data**. The comment in **struct bpf_sock_ops**
+ * has details on what skb_data contains under different
+ * *skops*\ **->op**.
+ *
+ * The first byte of the *searchby_res* specifies the
+ * kind that it wants to search.
+ *
+ * If the searching kind is an experimental kind
+ * (i.e. 253 or 254 according to RFC6994). It also
+ * needs to specify the "magic" which is either
+ * 2 bytes or 4 bytes. It then also needs to
+ * specify the size of the magic by using
+ * the 2nd byte which is "kind-length" of a TCP
+ * header option and the "kind-length" also
+ * includes the first 2 bytes "kind" and "kind-length"
+ * itself as a normal TCP header option also does.
+ *
+ * For example, to search experimental kind 254 with
+ * 2 byte magic 0xeB9F, the searchby_res should be
+ * [ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
+ *
+ * To search for the standard window scale option (3),
+ * the *searchby_res* should be [ 3, 0, 0, .... 0 ].
+ * Note, kind-length must be 0 for regular option.
+ *
+ * Searching for No-Op (0) and End-of-Option-List (1) are
+ * not supported.
+ *
+ * *len* must be at least 2 bytes which is the minimal size
+ * of a header option.
+ *
+ * Supported flags:
+ *
+ * * **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
+ * saved_syn packet or the just-received syn packet.
+ *
+ * Return
+ * > 0 when found, the header option is copied to *searchby_res*.
+ * The return value is the total length copied. On failure, a
+ * negative error code is returned:
+ *
+ * **-EINVAL** if a parameter is invalid.
+ *
+ * **-ENOMSG** if the option is not found.
+ *
+ * **-ENOENT** if no syn packet is available when
+ * **BPF_LOAD_HDR_OPT_TCP_SYN** is used.
+ *
+ * **-ENOSPC** if there is not enough space. Only *len* number of
+ * bytes are copied.
+ *
+ * **-EFAULT** on failure to parse the header options in the
+ * packet.
+ *
+ * **-EPERM** if the helper cannot be used under the current
+ * *skops*\ **->op**.
+ *
+ * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
+ * Description
+ * Store header option. The data will be copied
+ * from buffer *from* with length *len* to the TCP header.
+ *
+ * The buffer *from* should have the whole option that
+ * includes the kind, kind-length, and the actual
+ * option data. The *len* must be at least kind-length
+ * long. The kind-length does not have to be 4 byte
+ * aligned. The kernel will take care of the padding
+ * and setting the 4 bytes aligned value to th->doff.
+ *
+ * This helper will check for duplicated option
+ * by searching the same option in the outgoing skb.
+ *
+ * This helper can only be called during
+ * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
+ *
+ * Return
+ * 0 on success, or negative error in case of failure:
+ *
+ * **-EINVAL** If param is invalid.
+ *
+ * **-ENOSPC** if there is not enough space in the header.
+ * Nothing has been written
+ *
+ * **-EEXIST** if the option already exists.
+ *
+ * **-EFAULT** on failrue to parse the existing header options.
+ *
+ * **-EPERM** if the helper cannot be used under the current
+ * *skops*\ **->op**.
+ *
+ * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
+ * Description
+ * Reserve *len* bytes for the bpf header option. The
+ * space will be used by **bpf_store_hdr_opt**\ () later in
+ * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
+ *
+ * If **bpf_reserve_hdr_opt**\ () is called multiple times,
+ * the total number of bytes will be reserved.
+ *
+ * This helper can only be called during
+ * **BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
+ *
+ * Return
+ * 0 on success, or negative error in case of failure:
+ *
+ * **-EINVAL** if a parameter is invalid.
+ *
+ * **-ENOSPC** if there is not enough space in the header.
+ *
+ * **-EPERM** if the helper cannot be used under the current
+ * *skops*\ **->op**.
+ *
+ * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
+ * Description
+ * Get a bpf_local_storage from an *inode*.
+ *
+ * Logically, it could be thought of as getting the value from
+ * a *map* with *inode* as the **key**. From this
+ * perspective, the usage is not much different from
+ * **bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
+ * helper enforces the key must be an inode and the map must also
+ * be a **BPF_MAP_TYPE_INODE_STORAGE**.
+ *
+ * Underneath, the value is stored locally at *inode* instead of
+ * the *map*. The *map* is used as the bpf-local-storage
+ * "type". The bpf-local-storage "type" (i.e. the *map*) is
+ * searched against all bpf_local_storage residing at *inode*.
+ *
+ * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
+ * used such that a new bpf_local_storage will be
+ * created if one does not exist. *value* can be used
+ * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
+ * the initial value of a bpf_local_storage. If *value* is
+ * **NULL**, the new bpf_local_storage will be zero initialized.
+ * Return
+ * A bpf_local_storage pointer is returned on success.
+ *
+ * **NULL** if not found or there was an error in adding
+ * a new bpf_local_storage.
+ *
+ * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
+ * Description
+ * Delete a bpf_local_storage from an *inode*.
+ * Return
+ * 0 on success.
+ *
+ * **-ENOENT** if the bpf_local_storage cannot be found.
+ *
+ * long bpf_d_path(struct path *path, char *buf, u32 sz)
+ * Description
+ * Return full path for given **struct path** object, which
+ * needs to be the kernel BTF *path* object. The path is
+ * returned in the provided buffer *buf* of size *sz* and
+ * is zero terminated.
+ *
+ * Return
+ * On success, the strictly positive length of the string,
+ * including the trailing NUL character. On error, a negative
+ * value.
+ *
+ * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
+ * Description
+ * Read *size* bytes from user space address *user_ptr* and store
+ * the data in *dst*. This is a wrapper of **copy_from_user**\ ().
+ * Return
+ * 0 on success, or a negative error in case of failure.
+ *
+ * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
+ * Description
+ * Use BTF to store a string representation of *ptr*->ptr in *str*,
+ * using *ptr*->type_id. This value should specify the type
+ * that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
+ * can be used to look up vmlinux BTF type ids. Traversing the
+ * data structure using BTF, the type information and values are
+ * stored in the first *str_size* - 1 bytes of *str*. Safe copy of
+ * the pointer data is carried out to avoid kernel crashes during
+ * operation. Smaller types can use string space on the stack;
+ * larger programs can use map data to store the string
+ * representation.
+ *
+ * The string can be subsequently shared with userspace via
+ * bpf_perf_event_output() or ring buffer interfaces.
+ * bpf_trace_printk() is to be avoided as it places too small
+ * a limit on string size to be useful.
+ *
+ * *flags* is a combination of
+ *
+ * **BTF_F_COMPACT**
+ * no formatting around type information
+ * **BTF_F_NONAME**
+ * no struct/union member names/types
+ * **BTF_F_PTR_RAW**
+ * show raw (unobfuscated) pointer values;
+ * equivalent to printk specifier %px.
+ * **BTF_F_ZERO**
+ * show zero-valued struct/union members; they
+ * are not displayed by default
+ *
+ * Return
+ * The number of bytes that were written (or would have been
+ * written if output had to be truncated due to string size),
+ * or a negative error in cases of failure.
+ *
+ * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
+ * Description
+ * Use BTF to write to seq_write a string representation of
+ * *ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
+ * *flags* are identical to those used for bpf_snprintf_btf.
+ * Return
+ * 0 on success or a negative error in case of failure.
+ *
+ * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
+ * Description
+ * See **bpf_get_cgroup_classid**\ () for the main description.
+ * This helper differs from **bpf_get_cgroup_classid**\ () in that
+ * the cgroup v1 net_cls class is retrieved only from the *skb*'s
+ * associated socket instead of the current process.
+ * Return
+ * The id is returned or 0 in case the id could not be retrieved.
+ *
+ * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
+ * Description
+ * Redirect the packet to another net device of index *ifindex*
+ * and fill in L2 addresses from neighboring subsystem. This helper
+ * is somewhat similar to **bpf_redirect**\ (), except that it
+ * populates L2 addresses as well, meaning, internally, the helper
+ * relies on the neighbor lookup for the L2 address of the nexthop.
+ *
+ * The helper will perform a FIB lookup based on the skb's
+ * networking header to get the address of the next hop, unless
+ * this is supplied by the caller in the *params* argument. The
+ * *plen* argument indicates the len of *params* and should be set
+ * to 0 if *params* is NULL.
+ *
+ * The *flags* argument is reserved and must be 0. The helper is
+ * currently only supported for tc BPF program types, and enabled
+ * for IPv4 and IPv6 protocols.
+ * Return
+ * The helper returns **TC_ACT_REDIRECT** on success or
+ * **TC_ACT_SHOT** on error.
+ *
+ * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
+ * Description
+ * Take a pointer to a percpu ksym, *percpu_ptr*, and return a
+ * pointer to the percpu kernel variable on *cpu*. A ksym is an
+ * extern variable decorated with '__ksym'. For ksym, there is a
+ * global var (either static or global) defined of the same name
+ * in the kernel. The ksym is percpu if the global var is percpu.
+ * The returned pointer points to the global percpu var on *cpu*.
+ *
+ * bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
+ * kernel, except that bpf_per_cpu_ptr() may return NULL. This
+ * happens if *cpu* is larger than nr_cpu_ids. The caller of
+ * bpf_per_cpu_ptr() must check the returned value.
+ * Return
+ * A pointer pointing to the kernel percpu variable on *cpu*, or
+ * NULL, if *cpu* is invalid.
+ *
+ * void *bpf_this_cpu_ptr(const void *percpu_ptr)
+ * Description
+ * Take a pointer to a percpu ksym, *percpu_ptr*, and return a
+ * pointer to the percpu kernel variable on this cpu. See the
+ * description of 'ksym' in **bpf_per_cpu_ptr**\ ().
+ *
+ * bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
+ * the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
+ * never return NULL.
+ * Return
+ * A pointer pointing to the kernel percpu variable on this cpu.
+ *
+ * long bpf_redirect_peer(u32 ifindex, u64 flags)
+ * Description
+ * Redirect the packet to another net device of index *ifindex*.
+ * This helper is somewhat similar to **bpf_redirect**\ (), except
+ * that the redirection happens to the *ifindex*' peer device and
+ * the netns switch takes place from ingress to ingress without
+ * going through the CPU's backlog queue.
+ *
+ * The *flags* argument is reserved and must be 0. The helper is
+ * currently only supported for tc BPF program types at the ingress
+ * hook and for veth device types. The peer device must reside in a
+ * different network namespace.
+ * Return
+ * The helper returns **TC_ACT_REDIRECT** on success or
+ * **TC_ACT_SHOT** on error.
+ */
+#define __BPF_FUNC_MAPPER(FN) \
+ FN(unspec), \
+ FN(map_lookup_elem), \
+ FN(map_update_elem), \
+ FN(map_delete_elem), \
+ FN(probe_read), \
+ FN(ktime_get_ns), \
+ FN(trace_printk), \
+ FN(get_prandom_u32), \
+ FN(get_smp_processor_id), \
+ FN(skb_store_bytes), \
+ FN(l3_csum_replace), \
+ FN(l4_csum_replace), \
+ FN(tail_call), \
+ FN(clone_redirect), \
+ FN(get_current_pid_tgid), \
+ FN(get_current_uid_gid), \
+ FN(get_current_comm), \
+ FN(get_cgroup_classid), \
+ FN(skb_vlan_push), \
+ FN(skb_vlan_pop), \
+ FN(skb_get_tunnel_key), \
+ FN(skb_set_tunnel_key), \
+ FN(perf_event_read), \
+ FN(redirect), \
+ FN(get_route_realm), \
+ FN(perf_event_output), \
+ FN(skb_load_bytes), \
+ FN(get_stackid), \
+ FN(csum_diff), \
+ FN(skb_get_tunnel_opt), \
+ FN(skb_set_tunnel_opt), \
+ FN(skb_change_proto), \
+ FN(skb_change_type), \
+ FN(skb_under_cgroup), \
+ FN(get_hash_recalc), \
+ FN(get_current_task), \
+ FN(probe_write_user), \
+ FN(current_task_under_cgroup), \
+ FN(skb_change_tail), \
+ FN(skb_pull_data), \
+ FN(csum_update), \
+ FN(set_hash_invalid), \
+ FN(get_numa_node_id), \
+ FN(skb_change_head), \
+ FN(xdp_adjust_head), \
+ FN(probe_read_str), \
+ FN(get_socket_cookie), \
+ FN(get_socket_uid), \
+ FN(set_hash), \
+ FN(setsockopt), \
+ FN(skb_adjust_room), \
+ FN(redirect_map), \
+ FN(sk_redirect_map), \
+ FN(sock_map_update), \
+ FN(xdp_adjust_meta), \
+ FN(perf_event_read_value), \
+ FN(perf_prog_read_value), \
+ FN(getsockopt), \
+ FN(override_return), \
+ FN(sock_ops_cb_flags_set), \
+ FN(msg_redirect_map), \
+ FN(msg_apply_bytes), \
+ FN(msg_cork_bytes), \
+ FN(msg_pull_data), \
+ FN(bind), \
+ FN(xdp_adjust_tail), \
+ FN(skb_get_xfrm_state), \
+ FN(get_stack), \
+ FN(skb_load_bytes_relative), \
+ FN(fib_lookup), \
+ FN(sock_hash_update), \
+ FN(msg_redirect_hash), \
+ FN(sk_redirect_hash), \
+ FN(lwt_push_encap), \
+ FN(lwt_seg6_store_bytes), \
+ FN(lwt_seg6_adjust_srh), \
+ FN(lwt_seg6_action), \
+ FN(rc_repeat), \
+ FN(rc_keydown), \
+ FN(skb_cgroup_id), \
+ FN(get_current_cgroup_id), \
+ FN(get_local_storage), \
+ FN(sk_select_reuseport), \
+ FN(skb_ancestor_cgroup_id), \
+ FN(sk_lookup_tcp), \
+ FN(sk_lookup_udp), \
+ FN(sk_release), \
+ FN(map_push_elem), \
+ FN(map_pop_elem), \
+ FN(map_peek_elem), \
+ FN(msg_push_data), \
+ FN(msg_pop_data), \
+ FN(rc_pointer_rel), \
+ FN(spin_lock), \
+ FN(spin_unlock), \
+ FN(sk_fullsock), \
+ FN(tcp_sock), \
+ FN(skb_ecn_set_ce), \
+ FN(get_listener_sock), \
+ FN(skc_lookup_tcp), \
+ FN(tcp_check_syncookie), \
+ FN(sysctl_get_name), \
+ FN(sysctl_get_current_value), \
+ FN(sysctl_get_new_value), \
+ FN(sysctl_set_new_value), \
+ FN(strtol), \
+ FN(strtoul), \
+ FN(sk_storage_get), \
+ FN(sk_storage_delete), \
+ FN(send_signal), \
+ FN(tcp_gen_syncookie), \
+ FN(skb_output), \
+ FN(probe_read_user), \
+ FN(probe_read_kernel), \
+ FN(probe_read_user_str), \
+ FN(probe_read_kernel_str), \
+ FN(tcp_send_ack), \
+ FN(send_signal_thread), \
+ FN(jiffies64), \
+ FN(read_branch_records), \
+ FN(get_ns_current_pid_tgid), \
+ FN(xdp_output), \
+ FN(get_netns_cookie), \
+ FN(get_current_ancestor_cgroup_id), \
+ FN(sk_assign), \
+ FN(ktime_get_boot_ns), \
+ FN(seq_printf), \
+ FN(seq_write), \
+ FN(sk_cgroup_id), \
+ FN(sk_ancestor_cgroup_id), \
+ FN(ringbuf_output), \
+ FN(ringbuf_reserve), \
+ FN(ringbuf_submit), \
+ FN(ringbuf_discard), \
+ FN(ringbuf_query), \
+ FN(csum_level), \
+ FN(skc_to_tcp6_sock), \
+ FN(skc_to_tcp_sock), \
+ FN(skc_to_tcp_timewait_sock), \
+ FN(skc_to_tcp_request_sock), \
+ FN(skc_to_udp6_sock), \
+ FN(get_task_stack), \
+ FN(load_hdr_opt), \
+ FN(store_hdr_opt), \
+ FN(reserve_hdr_opt), \
+ FN(inode_storage_get), \
+ FN(inode_storage_delete), \
+ FN(d_path), \
+ FN(copy_from_user), \
+ FN(snprintf_btf), \
+ FN(seq_printf_btf), \
+ FN(skb_cgroup_classid), \
+ FN(redirect_neigh), \
+ FN(per_cpu_ptr), \
+ FN(this_cpu_ptr), \
+ FN(redirect_peer), \
+ /* */
+
+/* integer value in 'imm' field of BPF_CALL instruction selects which helper
+ * function eBPF program intends to call
+ */
+#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
+enum bpf_func_id {
+ __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
+ __BPF_FUNC_MAX_ID,
+};
+#undef __BPF_ENUM_FN
+
+/* All flags used by eBPF helper functions, placed here. */
+
+/* BPF_FUNC_skb_store_bytes flags. */
+enum {
+ BPF_F_RECOMPUTE_CSUM = (1ULL << 0),
+ BPF_F_INVALIDATE_HASH = (1ULL << 1),
+};
+
+/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
+ * First 4 bits are for passing the header field size.
+ */
+enum {
+ BPF_F_HDR_FIELD_MASK = 0xfULL,
+};
+
+/* BPF_FUNC_l4_csum_replace flags. */
+enum {
+ BPF_F_PSEUDO_HDR = (1ULL << 4),
+ BPF_F_MARK_MANGLED_0 = (1ULL << 5),
+ BPF_F_MARK_ENFORCE = (1ULL << 6),
+};
+
+/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
+enum {
+ BPF_F_INGRESS = (1ULL << 0),
+};
+
+/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
+enum {
+ BPF_F_TUNINFO_IPV6 = (1ULL << 0),
+};
+
+/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
+enum {
+ BPF_F_SKIP_FIELD_MASK = 0xffULL,
+ BPF_F_USER_STACK = (1ULL << 8),
+/* flags used by BPF_FUNC_get_stackid only. */
+ BPF_F_FAST_STACK_CMP = (1ULL << 9),
+ BPF_F_REUSE_STACKID = (1ULL << 10),
+/* flags used by BPF_FUNC_get_stack only. */
+ BPF_F_USER_BUILD_ID = (1ULL << 11),
+};
+
+/* BPF_FUNC_skb_set_tunnel_key flags. */
+enum {
+ BPF_F_ZERO_CSUM_TX = (1ULL << 1),
+ BPF_F_DONT_FRAGMENT = (1ULL << 2),
+ BPF_F_SEQ_NUMBER = (1ULL << 3),
+};
+
+/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
+ * BPF_FUNC_perf_event_read_value flags.
+ */
+enum {
+ BPF_F_INDEX_MASK = 0xffffffffULL,
+ BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK,
+/* BPF_FUNC_perf_event_output for sk_buff input context. */
+ BPF_F_CTXLEN_MASK = (0xfffffULL << 32),
+};
+
+/* Current network namespace */
+enum {
+ BPF_F_CURRENT_NETNS = (-1L),
+};
+
+/* BPF_FUNC_csum_level level values. */
+enum {
+ BPF_CSUM_LEVEL_QUERY,
+ BPF_CSUM_LEVEL_INC,
+ BPF_CSUM_LEVEL_DEC,
+ BPF_CSUM_LEVEL_RESET,
+};
+
+/* BPF_FUNC_skb_adjust_room flags. */
+enum {
+ BPF_F_ADJ_ROOM_FIXED_GSO = (1ULL << 0),
+ BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 = (1ULL << 1),
+ BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 = (1ULL << 2),
+ BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (1ULL << 3),
+ BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (1ULL << 4),
+ BPF_F_ADJ_ROOM_NO_CSUM_RESET = (1ULL << 5),
+};
+
+enum {
+ BPF_ADJ_ROOM_ENCAP_L2_MASK = 0xff,
+ BPF_ADJ_ROOM_ENCAP_L2_SHIFT = 56,
+};
+
+#define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \
+ BPF_ADJ_ROOM_ENCAP_L2_MASK) \
+ << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
+
+/* BPF_FUNC_sysctl_get_name flags. */
+enum {
+ BPF_F_SYSCTL_BASE_NAME = (1ULL << 0),
+};
+
+/* BPF_FUNC_<kernel_obj>_storage_get flags */
+enum {
+ BPF_LOCAL_STORAGE_GET_F_CREATE = (1ULL << 0),
+ /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
+ * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
+ */
+ BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE,
+};
+
+/* BPF_FUNC_read_branch_records flags. */
+enum {
+ BPF_F_GET_BRANCH_RECORDS_SIZE = (1ULL << 0),
+};
+
+/* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
+ * BPF_FUNC_bpf_ringbuf_output flags.
+ */
+enum {
+ BPF_RB_NO_WAKEUP = (1ULL << 0),
+ BPF_RB_FORCE_WAKEUP = (1ULL << 1),
+};
+
+/* BPF_FUNC_bpf_ringbuf_query flags */
+enum {
+ BPF_RB_AVAIL_DATA = 0,
+ BPF_RB_RING_SIZE = 1,
+ BPF_RB_CONS_POS = 2,
+ BPF_RB_PROD_POS = 3,
+};
+
+/* BPF ring buffer constants */
+enum {
+ BPF_RINGBUF_BUSY_BIT = (1U << 31),
+ BPF_RINGBUF_DISCARD_BIT = (1U << 30),
+ BPF_RINGBUF_HDR_SZ = 8,
+};
+
+/* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
+enum {
+ BPF_SK_LOOKUP_F_REPLACE = (1ULL << 0),
+ BPF_SK_LOOKUP_F_NO_REUSEPORT = (1ULL << 1),
+};
+
+/* Mode for BPF_FUNC_skb_adjust_room helper. */
+enum bpf_adj_room_mode {
+ BPF_ADJ_ROOM_NET,
+ BPF_ADJ_ROOM_MAC,
+};
+
+/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
+enum bpf_hdr_start_off {
+ BPF_HDR_START_MAC,
+ BPF_HDR_START_NET,
+};
+
+/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
+enum bpf_lwt_encap_mode {
+ BPF_LWT_ENCAP_SEG6,
+ BPF_LWT_ENCAP_SEG6_INLINE,
+ BPF_LWT_ENCAP_IP,
+};
+
+#define __bpf_md_ptr(type, name) \
+union { \
+ type name; \
+ __u64 :64; \
+} __attribute__((aligned(8)))
+
+/* user accessible mirror of in-kernel sk_buff.
+ * new fields can only be added to the end of this structure
+ */
+struct __sk_buff {
+ __u32 len;
+ __u32 pkt_type;
+ __u32 mark;
+ __u32 queue_mapping;
+ __u32 protocol;
+ __u32 vlan_present;
+ __u32 vlan_tci;
+ __u32 vlan_proto;
+ __u32 priority;
+ __u32 ingress_ifindex;
+ __u32 ifindex;
+ __u32 tc_index;
+ __u32 cb[5];
+ __u32 hash;
+ __u32 tc_classid;
+ __u32 data;
+ __u32 data_end;
+ __u32 napi_id;
+
+ /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
+ __u32 family;
+ __u32 remote_ip4; /* Stored in network byte order */
+ __u32 local_ip4; /* Stored in network byte order */
+ __u32 remote_ip6[4]; /* Stored in network byte order */
+ __u32 local_ip6[4]; /* Stored in network byte order */
+ __u32 remote_port; /* Stored in network byte order */
+ __u32 local_port; /* stored in host byte order */
+ /* ... here. */
+
+ __u32 data_meta;
+ __bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
+ __u64 tstamp;
+ __u32 wire_len;
+ __u32 gso_segs;
+ __bpf_md_ptr(struct bpf_sock *, sk);
+ __u32 gso_size;
+};
+
+struct bpf_tunnel_key {
+ __u32 tunnel_id;
+ union {
+ __u32 remote_ipv4;
+ __u32 remote_ipv6[4];
+ };
+ __u8 tunnel_tos;
+ __u8 tunnel_ttl;
+ __u16 tunnel_ext; /* Padding, future use. */
+ __u32 tunnel_label;
+};
+
+/* user accessible mirror of in-kernel xfrm_state.
+ * new fields can only be added to the end of this structure
+ */
+struct bpf_xfrm_state {
+ __u32 reqid;
+ __u32 spi; /* Stored in network byte order */
+ __u16 family;
+ __u16 ext; /* Padding, future use. */
+ union {
+ __u32 remote_ipv4; /* Stored in network byte order */
+ __u32 remote_ipv6[4]; /* Stored in network byte order */
+ };
+};
+
+/* Generic BPF return codes which all BPF program types may support.
+ * The values are binary compatible with their TC_ACT_* counter-part to
+ * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
+ * programs.
+ *
+ * XDP is handled seprately, see XDP_*.
+ */
+enum bpf_ret_code {
+ BPF_OK = 0,
+ /* 1 reserved */
+ BPF_DROP = 2,
+ /* 3-6 reserved */
+ BPF_REDIRECT = 7,
+ /* >127 are reserved for prog type specific return codes.
+ *
+ * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
+ * BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
+ * changed and should be routed based on its new L3 header.
+ * (This is an L3 redirect, as opposed to L2 redirect
+ * represented by BPF_REDIRECT above).
+ */
+ BPF_LWT_REROUTE = 128,
+};
+
+struct bpf_sock {
+ __u32 bound_dev_if;
+ __u32 family;
+ __u32 type;
+ __u32 protocol;
+ __u32 mark;
+ __u32 priority;
+ /* IP address also allows 1 and 2 bytes access */
+ __u32 src_ip4;
+ __u32 src_ip6[4];
+ __u32 src_port; /* host byte order */
+ __u32 dst_port; /* network byte order */
+ __u32 dst_ip4;
+ __u32 dst_ip6[4];
+ __u32 state;
+ __s32 rx_queue_mapping;
+};
+
+struct bpf_tcp_sock {
+ __u32 snd_cwnd; /* Sending congestion window */
+ __u32 srtt_us; /* smoothed round trip time << 3 in usecs */
+ __u32 rtt_min;
+ __u32 snd_ssthresh; /* Slow start size threshold */
+ __u32 rcv_nxt; /* What we want to receive next */
+ __u32 snd_nxt; /* Next sequence we send */
+ __u32 snd_una; /* First byte we want an ack for */
+ __u32 mss_cache; /* Cached effective mss, not including SACKS */
+ __u32 ecn_flags; /* ECN status bits. */
+ __u32 rate_delivered; /* saved rate sample: packets delivered */
+ __u32 rate_interval_us; /* saved rate sample: time elapsed */
+ __u32 packets_out; /* Packets which are "in flight" */
+ __u32 retrans_out; /* Retransmitted packets out */
+ __u32 total_retrans; /* Total retransmits for entire connection */
+ __u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
+ * total number of segments in.
+ */
+ __u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
+ * total number of data segments in.
+ */
+ __u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
+ * The total number of segments sent.
+ */
+ __u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
+ * total number of data segments sent.
+ */
+ __u32 lost_out; /* Lost packets */
+ __u32 sacked_out; /* SACK'd packets */
+ __u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
+ * sum(delta(rcv_nxt)), or how many bytes
+ * were acked.
+ */
+ __u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
+ * sum(delta(snd_una)), or how many bytes
+ * were acked.
+ */
+ __u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
+ * total number of DSACK blocks received
+ */
+ __u32 delivered; /* Total data packets delivered incl. rexmits */
+ __u32 delivered_ce; /* Like the above but only ECE marked packets */
+ __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
+};
+
+struct bpf_sock_tuple {
+ union {
+ struct {
+ __be32 saddr;
+ __be32 daddr;
+ __be16 sport;
+ __be16 dport;
+ } ipv4;
+ struct {
+ __be32 saddr[4];
+ __be32 daddr[4];
+ __be16 sport;
+ __be16 dport;
+ } ipv6;
+ };
+};
+
+struct bpf_xdp_sock {
+ __u32 queue_id;
+};
+
+#define XDP_PACKET_HEADROOM 256
+
+/* User return codes for XDP prog type.
+ * A valid XDP program must return one of these defined values. All other
+ * return codes are reserved for future use. Unknown return codes will
+ * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
+ */
+enum xdp_action {
+ XDP_ABORTED = 0,
+ XDP_DROP,
+ XDP_PASS,
+ XDP_TX,
+ XDP_REDIRECT,
+};
+
+/* user accessible metadata for XDP packet hook
+ * new fields must be added to the end of this structure
+ */
+struct xdp_md {
+ __u32 data;
+ __u32 data_end;
+ __u32 data_meta;
+ /* Below access go through struct xdp_rxq_info */
+ __u32 ingress_ifindex; /* rxq->dev->ifindex */
+ __u32 rx_queue_index; /* rxq->queue_index */
+
+ __u32 egress_ifindex; /* txq->dev->ifindex */
+};
+
+/* DEVMAP map-value layout
+ *
+ * The struct data-layout of map-value is a configuration interface.
+ * New members can only be added to the end of this structure.
+ */
+struct bpf_devmap_val {
+ __u32 ifindex; /* device index */
+ union {
+ int fd; /* prog fd on map write */
+ __u32 id; /* prog id on map read */
+ } bpf_prog;
+};
+
+/* CPUMAP map-value layout
+ *
+ * The struct data-layout of map-value is a configuration interface.
+ * New members can only be added to the end of this structure.
+ */
+struct bpf_cpumap_val {
+ __u32 qsize; /* queue size to remote target CPU */
+ union {
+ int fd; /* prog fd on map write */
+ __u32 id; /* prog id on map read */
+ } bpf_prog;
+};
+
+enum sk_action {
+ SK_DROP = 0,
+ SK_PASS,
+};
+
+/* user accessible metadata for SK_MSG packet hook, new fields must
+ * be added to the end of this structure
+ */
+struct sk_msg_md {
+ __bpf_md_ptr(void *, data);
+ __bpf_md_ptr(void *, data_end);
+
+ __u32 family;
+ __u32 remote_ip4; /* Stored in network byte order */
+ __u32 local_ip4; /* Stored in network byte order */
+ __u32 remote_ip6[4]; /* Stored in network byte order */
+ __u32 local_ip6[4]; /* Stored in network byte order */
+ __u32 remote_port; /* Stored in network byte order */
+ __u32 local_port; /* stored in host byte order */
+ __u32 size; /* Total size of sk_msg */
+
+ __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
+};
+
+struct sk_reuseport_md {
+ /*
+ * Start of directly accessible data. It begins from
+ * the tcp/udp header.
+ */
+ __bpf_md_ptr(void *, data);
+ /* End of directly accessible data */
+ __bpf_md_ptr(void *, data_end);
+ /*
+ * Total length of packet (starting from the tcp/udp header).
+ * Note that the directly accessible bytes (data_end - data)
+ * could be less than this "len". Those bytes could be
+ * indirectly read by a helper "bpf_skb_load_bytes()".
+ */
+ __u32 len;
+ /*
+ * Eth protocol in the mac header (network byte order). e.g.
+ * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
+ */
+ __u32 eth_protocol;
+ __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
+ __u32 bind_inany; /* Is sock bound to an INANY address? */
+ __u32 hash; /* A hash of the packet 4 tuples */
+};
+
+#define BPF_TAG_SIZE 8
+
+struct bpf_prog_info {
+ __u32 type;
+ __u32 id;
+ __u8 tag[BPF_TAG_SIZE];
+ __u32 jited_prog_len;
+ __u32 xlated_prog_len;
+ __aligned_u64 jited_prog_insns;
+ __aligned_u64 xlated_prog_insns;
+ __u64 load_time; /* ns since boottime */
+ __u32 created_by_uid;
+ __u32 nr_map_ids;
+ __aligned_u64 map_ids;
+ char name[BPF_OBJ_NAME_LEN];
+ __u32 ifindex;
+ __u32 gpl_compatible:1;
+ __u32 :31; /* alignment pad */
+ __u64 netns_dev;
+ __u64 netns_ino;
+ __u32 nr_jited_ksyms;
+ __u32 nr_jited_func_lens;
+ __aligned_u64 jited_ksyms;
+ __aligned_u64 jited_func_lens;
+ __u32 btf_id;
+ __u32 func_info_rec_size;
+ __aligned_u64 func_info;
+ __u32 nr_func_info;
+ __u32 nr_line_info;
+ __aligned_u64 line_info;
+ __aligned_u64 jited_line_info;
+ __u32 nr_jited_line_info;
+ __u32 line_info_rec_size;
+ __u32 jited_line_info_rec_size;
+ __u32 nr_prog_tags;
+ __aligned_u64 prog_tags;
+ __u64 run_time_ns;
+ __u64 run_cnt;
+} __attribute__((aligned(8)));
+
+struct bpf_map_info {
+ __u32 type;
+ __u32 id;
+ __u32 key_size;
+ __u32 value_size;
+ __u32 max_entries;
+ __u32 map_flags;
+ char name[BPF_OBJ_NAME_LEN];
+ __u32 ifindex;
+ __u32 btf_vmlinux_value_type_id;
+ __u64 netns_dev;
+ __u64 netns_ino;
+ __u32 btf_id;
+ __u32 btf_key_type_id;
+ __u32 btf_value_type_id;
+} __attribute__((aligned(8)));
+
+struct bpf_btf_info {
+ __aligned_u64 btf;
+ __u32 btf_size;
+ __u32 id;
+} __attribute__((aligned(8)));
+
+struct bpf_link_info {
+ __u32 type;
+ __u32 id;
+ __u32 prog_id;
+ union {
+ struct {
+ __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
+ __u32 tp_name_len; /* in/out: tp_name buffer len */
+ } raw_tracepoint;
+ struct {
+ __u32 attach_type;
+ } tracing;
+ struct {
+ __u64 cgroup_id;
+ __u32 attach_type;
+ } cgroup;
+ struct {
+ __aligned_u64 target_name; /* in/out: target_name buffer ptr */
+ __u32 target_name_len; /* in/out: target_name buffer len */
+ union {
+ struct {
+ __u32 map_id;
+ } map;
+ };
+ } iter;
+ struct {
+ __u32 netns_ino;
+ __u32 attach_type;
+ } netns;
+ struct {
+ __u32 ifindex;
+ } xdp;
+ };
+} __attribute__((aligned(8)));
+
+/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
+ * by user and intended to be used by socket (e.g. to bind to, depends on
+ * attach type).
+ */
+struct bpf_sock_addr {
+ __u32 user_family; /* Allows 4-byte read, but no write. */
+ __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
+ * Stored in network byte order.
+ */
+ __u32 user_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
+ * Stored in network byte order.
+ */
+ __u32 user_port; /* Allows 1,2,4-byte read and 4-byte write.
+ * Stored in network byte order
+ */
+ __u32 family; /* Allows 4-byte read, but no write */
+ __u32 type; /* Allows 4-byte read, but no write */
+ __u32 protocol; /* Allows 4-byte read, but no write */
+ __u32 msg_src_ip4; /* Allows 1,2,4-byte read and 4-byte write.
+ * Stored in network byte order.
+ */
+ __u32 msg_src_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
+ * Stored in network byte order.
+ */
+ __bpf_md_ptr(struct bpf_sock *, sk);
+};
+
+/* User bpf_sock_ops struct to access socket values and specify request ops
+ * and their replies.
+ * Some of this fields are in network (bigendian) byte order and may need
+ * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
+ * New fields can only be added at the end of this structure
+ */
+struct bpf_sock_ops {
+ __u32 op;
+ union {
+ __u32 args[4]; /* Optionally passed to bpf program */
+ __u32 reply; /* Returned by bpf program */
+ __u32 replylong[4]; /* Optionally returned by bpf prog */
+ };
+ __u32 family;
+ __u32 remote_ip4; /* Stored in network byte order */
+ __u32 local_ip4; /* Stored in network byte order */
+ __u32 remote_ip6[4]; /* Stored in network byte order */
+ __u32 local_ip6[4]; /* Stored in network byte order */
+ __u32 remote_port; /* Stored in network byte order */
+ __u32 local_port; /* stored in host byte order */
+ __u32 is_fullsock; /* Some TCP fields are only valid if
+ * there is a full socket. If not, the
+ * fields read as zero.
+ */
+ __u32 snd_cwnd;
+ __u32 srtt_us; /* Averaged RTT << 3 in usecs */
+ __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
+ __u32 state;
+ __u32 rtt_min;
+ __u32 snd_ssthresh;
+ __u32 rcv_nxt;
+ __u32 snd_nxt;
+ __u32 snd_una;
+ __u32 mss_cache;
+ __u32 ecn_flags;
+ __u32 rate_delivered;
+ __u32 rate_interval_us;
+ __u32 packets_out;
+ __u32 retrans_out;
+ __u32 total_retrans;
+ __u32 segs_in;
+ __u32 data_segs_in;
+ __u32 segs_out;
+ __u32 data_segs_out;
+ __u32 lost_out;
+ __u32 sacked_out;
+ __u32 sk_txhash;
+ __u64 bytes_received;
+ __u64 bytes_acked;
+ __bpf_md_ptr(struct bpf_sock *, sk);
+ /* [skb_data, skb_data_end) covers the whole TCP header.
+ *
+ * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
+ * BPF_SOCK_OPS_HDR_OPT_LEN_CB: Not useful because the
+ * header has not been written.
+ * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
+ * been written so far.
+ * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: The SYNACK that concludes
+ * the 3WHS.
+ * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
+ * the 3WHS.
+ *
+ * bpf_load_hdr_opt() can also be used to read a particular option.
+ */
+ __bpf_md_ptr(void *, skb_data);
+ __bpf_md_ptr(void *, skb_data_end);
+ __u32 skb_len; /* The total length of a packet.
+ * It includes the header, options,
+ * and payload.
+ */
+ __u32 skb_tcp_flags; /* tcp_flags of the header. It provides
+ * an easy way to check for tcp_flags
+ * without parsing skb_data.
+ *
+ * In particular, the skb_tcp_flags
+ * will still be available in
+ * BPF_SOCK_OPS_HDR_OPT_LEN even though
+ * the outgoing header has not
+ * been written yet.
+ */
+};
+
+/* Definitions for bpf_sock_ops_cb_flags */
+enum {
+ BPF_SOCK_OPS_RTO_CB_FLAG = (1<<0),
+ BPF_SOCK_OPS_RETRANS_CB_FLAG = (1<<1),
+ BPF_SOCK_OPS_STATE_CB_FLAG = (1<<2),
+ BPF_SOCK_OPS_RTT_CB_FLAG = (1<<3),
+ /* Call bpf for all received TCP headers. The bpf prog will be
+ * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
+ *
+ * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
+ * for the header option related helpers that will be useful
+ * to the bpf programs.
+ *
+ * It could be used at the client/active side (i.e. connect() side)
+ * when the server told it that the server was in syncookie
+ * mode and required the active side to resend the bpf-written
+ * options. The active side can keep writing the bpf-options until
+ * it received a valid packet from the server side to confirm
+ * the earlier packet (and options) has been received. The later
+ * example patch is using it like this at the active side when the
+ * server is in syncookie mode.
+ *
+ * The bpf prog will usually turn this off in the common cases.
+ */
+ BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG = (1<<4),
+ /* Call bpf when kernel has received a header option that
+ * the kernel cannot handle. The bpf prog will be called under
+ * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
+ *
+ * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
+ * for the header option related helpers that will be useful
+ * to the bpf programs.
+ */
+ BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
+ /* Call bpf when the kernel is writing header options for the
+ * outgoing packet. The bpf prog will first be called
+ * to reserve space in a skb under
+ * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB. Then
+ * the bpf prog will be called to write the header option(s)
+ * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
+ *
+ * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
+ * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
+ * related helpers that will be useful to the bpf programs.
+ *
+ * The kernel gets its chance to reserve space and write
+ * options first before the BPF program does.
+ */
+ BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
+/* Mask of all currently supported cb flags */
+ BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F,
+};
+
+/* List of known BPF sock_ops operators.
+ * New entries can only be added at the end
+ */
+enum {
+ BPF_SOCK_OPS_VOID,
+ BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
+ * -1 if default value should be used
+ */
+ BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
+ * window (in packets) or -1 if default
+ * value should be used
+ */
+ BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
+ * active connection is initialized
+ */
+ BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
+ * active connection is
+ * established
+ */
+ BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
+ * passive connection is
+ * established
+ */
+ BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
+ * needs ECN
+ */
+ BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
+ * based on the path and may be
+ * dependent on the congestion control
+ * algorithm. In general it indicates
+ * a congestion threshold. RTTs above
+ * this indicate congestion
+ */
+ BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
+ * Arg1: value of icsk_retransmits
+ * Arg2: value of icsk_rto
+ * Arg3: whether RTO has expired
+ */
+ BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
+ * Arg1: sequence number of 1st byte
+ * Arg2: # segments
+ * Arg3: return value of
+ * tcp_transmit_skb (0 => success)
+ */
+ BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
+ * Arg1: old_state
+ * Arg2: new_state
+ */
+ BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
+ * socket transition to LISTEN state.
+ */
+ BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
+ */
+ BPF_SOCK_OPS_PARSE_HDR_OPT_CB, /* Parse the header option.
+ * It will be called to handle
+ * the packets received at
+ * an already established
+ * connection.
+ *
+ * sock_ops->skb_data:
+ * Referring to the received skb.
+ * It covers the TCP header only.
+ *
+ * bpf_load_hdr_opt() can also
+ * be used to search for a
+ * particular option.
+ */
+ BPF_SOCK_OPS_HDR_OPT_LEN_CB, /* Reserve space for writing the
+ * header option later in
+ * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
+ * Arg1: bool want_cookie. (in
+ * writing SYNACK only)
+ *
+ * sock_ops->skb_data:
+ * Not available because no header has
+ * been written yet.
+ *
+ * sock_ops->skb_tcp_flags:
+ * The tcp_flags of the
+ * outgoing skb. (e.g. SYN, ACK, FIN).
+ *
+ * bpf_reserve_hdr_opt() should
+ * be used to reserve space.
+ */
+ BPF_SOCK_OPS_WRITE_HDR_OPT_CB, /* Write the header options
+ * Arg1: bool want_cookie. (in
+ * writing SYNACK only)
+ *
+ * sock_ops->skb_data:
+ * Referring to the outgoing skb.
+ * It covers the TCP header
+ * that has already been written
+ * by the kernel and the
+ * earlier bpf-progs.
+ *
+ * sock_ops->skb_tcp_flags:
+ * The tcp_flags of the outgoing
+ * skb. (e.g. SYN, ACK, FIN).
+ *
+ * bpf_store_hdr_opt() should
+ * be used to write the
+ * option.
+ *
+ * bpf_load_hdr_opt() can also
+ * be used to search for a
+ * particular option that
+ * has already been written
+ * by the kernel or the
+ * earlier bpf-progs.
+ */
+};
+
+/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
+ * changes between the TCP and BPF versions. Ideally this should never happen.
+ * If it does, we need to add code to convert them before calling
+ * the BPF sock_ops function.
+ */
+enum {
+ BPF_TCP_ESTABLISHED = 1,
+ BPF_TCP_SYN_SENT,
+ BPF_TCP_SYN_RECV,
+ BPF_TCP_FIN_WAIT1,
+ BPF_TCP_FIN_WAIT2,
+ BPF_TCP_TIME_WAIT,
+ BPF_TCP_CLOSE,
+ BPF_TCP_CLOSE_WAIT,
+ BPF_TCP_LAST_ACK,
+ BPF_TCP_LISTEN,
+ BPF_TCP_CLOSING, /* Now a valid state */
+ BPF_TCP_NEW_SYN_RECV,
+
+ BPF_TCP_MAX_STATES /* Leave at the end! */
+};
+
+enum {
+ TCP_BPF_IW = 1001, /* Set TCP initial congestion window */
+ TCP_BPF_SNDCWND_CLAMP = 1002, /* Set sndcwnd_clamp */
+ TCP_BPF_DELACK_MAX = 1003, /* Max delay ack in usecs */
+ TCP_BPF_RTO_MIN = 1004, /* Min delay ack in usecs */
+ /* Copy the SYN pkt to optval
+ *
+ * BPF_PROG_TYPE_SOCK_OPS only. It is similar to the
+ * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
+ * to only getting from the saved_syn. It can either get the
+ * syn packet from:
+ *
+ * 1. the just-received SYN packet (only available when writing the
+ * SYNACK). It will be useful when it is not necessary to
+ * save the SYN packet for latter use. It is also the only way
+ * to get the SYN during syncookie mode because the syn
+ * packet cannot be saved during syncookie.
+ *
+ * OR
+ *
+ * 2. the earlier saved syn which was done by
+ * bpf_setsockopt(TCP_SAVE_SYN).
+ *
+ * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
+ * SYN packet is obtained.
+ *
+ * If the bpf-prog does not need the IP[46] header, the
+ * bpf-prog can avoid parsing the IP header by using
+ * TCP_BPF_SYN. Otherwise, the bpf-prog can get both
+ * IP[46] and TCP header by using TCP_BPF_SYN_IP.
+ *
+ * >0: Total number of bytes copied
+ * -ENOSPC: Not enough space in optval. Only optlen number of
+ * bytes is copied.
+ * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
+ * is not saved by setsockopt(TCP_SAVE_SYN).
+ */
+ TCP_BPF_SYN = 1005, /* Copy the TCP header */
+ TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */
+ TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */
+};
+
+enum {
+ BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
+};
+
+/* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
+ * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
+ */
+enum {
+ BPF_WRITE_HDR_TCP_CURRENT_MSS = 1, /* Kernel is finding the
+ * total option spaces
+ * required for an established
+ * sk in order to calculate the
+ * MSS. No skb is actually
+ * sent.
+ */
+ BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2, /* Kernel is in syncookie mode
+ * when sending a SYN.
+ */
+};
+
+struct bpf_perf_event_value {
+ __u64 counter;
+ __u64 enabled;
+ __u64 running;
+};
+
+enum {
+ BPF_DEVCG_ACC_MKNOD = (1ULL << 0),
+ BPF_DEVCG_ACC_READ = (1ULL << 1),
+ BPF_DEVCG_ACC_WRITE = (1ULL << 2),
+};
+
+enum {
+ BPF_DEVCG_DEV_BLOCK = (1ULL << 0),
+ BPF_DEVCG_DEV_CHAR = (1ULL << 1),
+};
+
+struct bpf_cgroup_dev_ctx {
+ /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
+ __u32 access_type;
+ __u32 major;
+ __u32 minor;
+};
+
+struct bpf_raw_tracepoint_args {
+ __u64 args[0];
+};
+
+/* DIRECT: Skip the FIB rules and go to FIB table associated with device
+ * OUTPUT: Do lookup from egress perspective; default is ingress
+ */
+enum {
+ BPF_FIB_LOOKUP_DIRECT = (1U << 0),
+ BPF_FIB_LOOKUP_OUTPUT = (1U << 1),
+};
+
+enum {
+ BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
+ BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
+ BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
+ BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
+ BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
+ BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
+ BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
+ BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
+ BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
+};
+
+struct bpf_fib_lookup {
+ /* input: network family for lookup (AF_INET, AF_INET6)
+ * output: network family of egress nexthop
+ */
+ __u8 family;
+
+ /* set if lookup is to consider L4 data - e.g., FIB rules */
+ __u8 l4_protocol;
+ __be16 sport;
+ __be16 dport;
+
+ /* total length of packet from network header - used for MTU check */
+ __u16 tot_len;
+
+ /* input: L3 device index for lookup
+ * output: device index from FIB lookup
+ */
+ __u32 ifindex;
+
+ union {
+ /* inputs to lookup */
+ __u8 tos; /* AF_INET */
+ __be32 flowinfo; /* AF_INET6, flow_label + priority */
+
+ /* output: metric of fib result (IPv4/IPv6 only) */
+ __u32 rt_metric;
+ };
+
+ union {
+ __be32 ipv4_src;
+ __u32 ipv6_src[4]; /* in6_addr; network order */
+ };
+
+ /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
+ * network header. output: bpf_fib_lookup sets to gateway address
+ * if FIB lookup returns gateway route
+ */
+ union {
+ __be32 ipv4_dst;
+ __u32 ipv6_dst[4]; /* in6_addr; network order */
+ };
+
+ /* output */
+ __be16 h_vlan_proto;
+ __be16 h_vlan_TCI;
+ __u8 smac[6]; /* ETH_ALEN */
+ __u8 dmac[6]; /* ETH_ALEN */
+};
+
+struct bpf_redir_neigh {
+ /* network family for lookup (AF_INET, AF_INET6) */
+ __u32 nh_family;
+ /* network address of nexthop; skips fib lookup to find gateway */
+ union {
+ __be32 ipv4_nh;
+ __u32 ipv6_nh[4]; /* in6_addr; network order */
+ };
+};
+
+enum bpf_task_fd_type {
+ BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
+ BPF_FD_TYPE_TRACEPOINT, /* tp name */
+ BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
+ BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
+ BPF_FD_TYPE_UPROBE, /* filename + offset */
+ BPF_FD_TYPE_URETPROBE, /* filename + offset */
+};
+
+enum {
+ BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG = (1U << 0),
+ BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL = (1U << 1),
+ BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP = (1U << 2),
+};
+
+struct bpf_flow_keys {
+ __u16 nhoff;
+ __u16 thoff;
+ __u16 addr_proto; /* ETH_P_* of valid addrs */
+ __u8 is_frag;
+ __u8 is_first_frag;
+ __u8 is_encap;
+ __u8 ip_proto;
+ __be16 n_proto;
+ __be16 sport;
+ __be16 dport;
+ union {
+ struct {
+ __be32 ipv4_src;
+ __be32 ipv4_dst;
+ };
+ struct {
+ __u32 ipv6_src[4]; /* in6_addr; network order */
+ __u32 ipv6_dst[4]; /* in6_addr; network order */
+ };
+ };
+ __u32 flags;
+ __be32 flow_label;
+};
+
+struct bpf_func_info {
+ __u32 insn_off;
+ __u32 type_id;
+};
+
+#define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
+#define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
+
+struct bpf_line_info {
+ __u32 insn_off;
+ __u32 file_name_off;
+ __u32 line_off;
+ __u32 line_col;
+};
+
+struct bpf_spin_lock {
+ __u32 val;
+};
+
+struct bpf_sysctl {
+ __u32 write; /* Sysctl is being read (= 0) or written (= 1).
+ * Allows 1,2,4-byte read, but no write.
+ */
+ __u32 file_pos; /* Sysctl file position to read from, write to.
+ * Allows 1,2,4-byte read an 4-byte write.
+ */
+};
+
+struct bpf_sockopt {
+ __bpf_md_ptr(struct bpf_sock *, sk);
+ __bpf_md_ptr(void *, optval);
+ __bpf_md_ptr(void *, optval_end);
+
+ __s32 level;
+ __s32 optname;
+ __s32 optlen;
+ __s32 retval;
+};
+
+struct bpf_pidns_info {
+ __u32 pid;
+ __u32 tgid;
+};
+
+/* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
+struct bpf_sk_lookup {
+ __bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
+
+ __u32 family; /* Protocol family (AF_INET, AF_INET6) */
+ __u32 protocol; /* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */
+ __u32 remote_ip4; /* Network byte order */
+ __u32 remote_ip6[4]; /* Network byte order */
+ __u32 remote_port; /* Network byte order */
+ __u32 local_ip4; /* Network byte order */
+ __u32 local_ip6[4]; /* Network byte order */
+ __u32 local_port; /* Host byte order */
+};
+
+/*
+ * struct btf_ptr is used for typed pointer representation; the
+ * type id is used to render the pointer data as the appropriate type
+ * via the bpf_snprintf_btf() helper described above. A flags field -
+ * potentially to specify additional details about the BTF pointer
+ * (rather than its mode of display) - is included for future use.
+ * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
+ */
+struct btf_ptr {
+ void *ptr;
+ __u32 type_id;
+ __u32 flags; /* BTF ptr flags; unused at present. */
+};
+
+/*
+ * Flags to control bpf_snprintf_btf() behaviour.
+ * - BTF_F_COMPACT: no formatting around type information
+ * - BTF_F_NONAME: no struct/union member names/types
+ * - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
+ * equivalent to %px.
+ * - BTF_F_ZERO: show zero-valued struct/union members; they
+ * are not displayed by default
+ */
+enum {
+ BTF_F_COMPACT = (1ULL << 0),
+ BTF_F_NONAME = (1ULL << 1),
+ BTF_F_PTR_RAW = (1ULL << 2),
+ BTF_F_ZERO = (1ULL << 3),
+};
+
+#endif /* _UAPI__LINUX_BPF_H__ */
projects / platform / upstream / connman.git / commitdiff