tools/testing/selftests/bpf/progs/bpf_iter_netlink.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2020 Facebook */
   3 /* "undefine" structs in vmlinux.h, because we "override" them below */
   4 #define bpf_iter_meta bpf_iter_meta___not_used
   5 #define bpf_iter__netlink bpf_iter__netlink___not_used
   6 #include "vmlinux.h"
   7 #undef bpf_iter_meta
   8 #undef bpf_iter__netlink
   9 #include <bpf/bpf_helpers.h>
  10 #include <bpf/bpf_tracing.h>
  11
  12 char _license[] SEC("license") = "GPL";
  13
  14 #define sk_rmem_alloc   sk_backlog.rmem_alloc
  15 #define sk_refcnt       __sk_common.skc_refcnt
  16
  17 struct bpf_iter_meta {
  18         struct seq_file *seq;
  19         __u64 session_id;
  20         __u64 seq_num;
  21 } __attribute__((preserve_access_index));
  22
  23 struct bpf_iter__netlink {
  24         struct bpf_iter_meta *meta;
  25         struct netlink_sock *sk;
  26 } __attribute__((preserve_access_index));
  27
  28 static inline struct inode *SOCK_INODE(struct socket *socket)
  29 {
  30         return &container_of(socket, struct socket_alloc, socket)->vfs_inode;
  31 }
  32
  33 SEC("iter/netlink")
  34 int dump_netlink(struct bpf_iter__netlink *ctx)
  35 {
  36         struct seq_file *seq = ctx->meta->seq;
  37         struct netlink_sock *nlk = ctx->sk;
  38         unsigned long group, ino;
  39         struct inode *inode;
  40         struct socket *sk;
  41         struct sock *s;
  42
  43         if (nlk == (void *)0)
  44                 return 0;
  45
  46         if (ctx->meta->seq_num == 0)
  47                 BPF_SEQ_PRINTF(seq, "sk               Eth Pid        Groups   "
  48                                     "Rmem     Wmem     Dump  Locks    Drops    "
  49                                     "Inode\n");
  50
  51         s = &nlk->sk;
  52         BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol);
  53
  54         if (!nlk->groups)  {
  55                 group = 0;
  56         } else {
  57                 /* FIXME: temporary use bpf_probe_read here, needs
  58                  * verifier support to do direct access.
  59                  */
  60                 bpf_probe_read(&group, sizeof(group), &nlk->groups[0]);
  61         }
  62         BPF_SEQ_PRINTF(seq, "%-10u %08x %-8d %-8d %-5d %-8d ",
  63                        nlk->portid, (u32)group,
  64                        s->sk_rmem_alloc.counter,
  65                        s->sk_wmem_alloc.refs.counter - 1,
  66                        nlk->cb_running, s->sk_refcnt.refs.counter);
  67
  68         sk = s->sk_socket;
  69         if (!sk) {
  70                 ino = 0;
  71         } else {
  72                 /* FIXME: container_of inside SOCK_INODE has a forced
  73                  * type conversion, and direct access cannot be used
  74                  * with current verifier.
  75                  */
  76                 inode = SOCK_INODE(sk);
  77                 bpf_probe_read(&ino, sizeof(ino), &inode->i_ino);
  78         }
  79         BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);
  80
  81         return 0;
  82 }