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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <stddef.h>
   3 #include <string.h>
   4 #include <netinet/in.h>
   5 #include <linux/bpf.h>
   6 #include <linux/if_ether.h>
   7 #include <linux/if_packet.h>
   8 #include <linux/ip.h>
   9 #include <linux/ipv6.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/tcp.h>
  13 #include <bpf/bpf_helpers.h>
  14 #include <bpf/bpf_endian.h>
  15 #include "bpf_tcp_helpers.h"
  16 #include "test_tcpbpf.h"
  17
  18 struct tcpbpf_globals global = {};
  19
  20 /**
  21  * SOL_TCP is defined in <netinet/tcp.h> while
  22  * TCP_SAVED_SYN is defined in already included <linux/tcp.h>
  23  */
  24 #ifndef SOL_TCP
  25 #define SOL_TCP 6
  26 #endif
  27
  28 static __always_inline int get_tp_window_clamp(struct bpf_sock_ops *skops)
  29 {
  30         struct bpf_sock *sk;
  31         struct tcp_sock *tp;
  32
  33         sk = skops->sk;
  34         if (!sk)
  35                 return -1;
  36         tp = bpf_skc_to_tcp_sock(sk);
  37         if (!tp)
  38                 return -1;
  39         return tp->window_clamp;
  40 }
  41
  42 SEC("sockops")
  43 int bpf_testcb(struct bpf_sock_ops *skops)
  44 {
  45         char header[sizeof(struct ipv6hdr) + sizeof(struct tcphdr)];
  46         struct bpf_sock_ops *reuse = skops;
  47         struct tcphdr *thdr;
  48         int window_clamp = 9216;
  49         int save_syn = 1;
  50         int rv = -1;
  51         int v = 0;
  52         int op;
  53
  54         /* Test reading fields in bpf_sock_ops using single register */
  55         asm volatile (
  56                 "%[reuse] = *(u32 *)(%[reuse] +96)"
  57                 : [reuse] "+r"(reuse)
  58                 :);
  59
  60         asm volatile (
  61                 "%[op] = *(u32 *)(%[skops] +96)"
  62                 : [op] "+r"(op)
  63                 : [skops] "r"(skops)
  64                 :);
  65
  66         asm volatile (
  67                 "r9 = %[skops];\n"
  68                 "r8 = *(u32 *)(r9 +164);\n"
  69                 "*(u32 *)(r9 +164) = r8;\n"
  70                 :: [skops] "r"(skops)
  71                 : "r9", "r8");
  72
  73         asm volatile (
  74                 "r1 = %[skops];\n"
  75                 "r1 = *(u64 *)(r1 +184);\n"
  76                 "if r1 == 0 goto +1;\n"
  77                 "r1 = *(u32 *)(r1 +4);\n"
  78                 :: [skops] "r"(skops):"r1");
  79
  80         asm volatile (
  81                 "r9 = %[skops];\n"
  82                 "r9 = *(u64 *)(r9 +184);\n"
  83                 "if r9 == 0 goto +1;\n"
  84                 "r9 = *(u32 *)(r9 +4);\n"
  85                 :: [skops] "r"(skops):"r9");
  86
  87         asm volatile (
  88                 "r1 = %[skops];\n"
  89                 "r2 = *(u64 *)(r1 +184);\n"
  90                 "if r2 == 0 goto +1;\n"
  91                 "r2 = *(u32 *)(r2 +4);\n"
  92                 :: [skops] "r"(skops):"r1", "r2");
  93
  94         op = (int) skops->op;
  95
  96         global.event_map |= (1 << op);
  97
  98         switch (op) {
  99         case BPF_SOCK_OPS_TCP_CONNECT_CB:
 100                 rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
 101                                     &window_clamp, sizeof(window_clamp));
 102                 global.window_clamp_client = get_tp_window_clamp(skops);
 103                 break;
 104         case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
 105                 /* Test failure to set largest cb flag (assumes not defined) */
 106                 global.bad_cb_test_rv = bpf_sock_ops_cb_flags_set(skops, 0x80);
 107                 /* Set callback */
 108                 global.good_cb_test_rv = bpf_sock_ops_cb_flags_set(skops,
 109                                                  BPF_SOCK_OPS_STATE_CB_FLAG);
 110                 break;
 111         case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
 112                 skops->sk_txhash = 0x12345f;
 113                 v = 0xff;
 114                 rv = bpf_setsockopt(skops, SOL_IPV6, IPV6_TCLASS, &v,
 115                                     sizeof(v));
 116                 if (skops->family == AF_INET6) {
 117                         v = bpf_getsockopt(skops, IPPROTO_TCP, TCP_SAVED_SYN,
 118                                            header, (sizeof(struct ipv6hdr) +
 119                                                     sizeof(struct tcphdr)));
 120                         if (!v) {
 121                                 int offset = sizeof(struct ipv6hdr);
 122
 123                                 thdr = (struct tcphdr *)(header + offset);
 124                                 v = thdr->syn;
 125
 126                                 global.tcp_saved_syn = v;
 127                         }
 128                 }
 129                 rv = bpf_setsockopt(skops, SOL_TCP, TCP_WINDOW_CLAMP,
 130                                     &window_clamp, sizeof(window_clamp));
 131
 132                 global.window_clamp_server = get_tp_window_clamp(skops);
 133                 break;
 134         case BPF_SOCK_OPS_RTO_CB:
 135                 break;
 136         case BPF_SOCK_OPS_RETRANS_CB:
 137                 break;
 138         case BPF_SOCK_OPS_STATE_CB:
 139                 if (skops->args[1] == BPF_TCP_CLOSE) {
 140                         if (skops->args[0] == BPF_TCP_LISTEN) {
 141                                 global.num_listen++;
 142                         } else {
 143                                 global.total_retrans = skops->total_retrans;
 144                                 global.data_segs_in = skops->data_segs_in;
 145                                 global.data_segs_out = skops->data_segs_out;
 146                                 global.bytes_received = skops->bytes_received;
 147                                 global.bytes_acked = skops->bytes_acked;
 148                         }
 149                         global.num_close_events++;
 150                 }
 151                 break;
 152         case BPF_SOCK_OPS_TCP_LISTEN_CB:
 153                 bpf_sock_ops_cb_flags_set(skops, BPF_SOCK_OPS_STATE_CB_FLAG);
 154                 v = bpf_setsockopt(skops, IPPROTO_TCP, TCP_SAVE_SYN,
 155                                    &save_syn, sizeof(save_syn));
 156                 /* Update global map w/ result of setsock opt */
 157                 global.tcp_save_syn = v;
 158                 break;
 159         default:
 160                 rv = -1;
 161         }
 162         skops->reply = rv;
 163         return 1;
 164 }
 165 char _license[] SEC("license") = "GPL";