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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2021 Facebook */
   3 #include "bpf_iter.h"
   4 #include "bpf_tracing_net.h"
   5 #include <bpf/bpf_helpers.h>
   6 #include <bpf/bpf_endian.h>
   7
   8 #define bpf_tcp_sk(skc) ({                              \
   9         struct sock_common *_skc = skc;                 \
  10         sk = NULL;                                      \
  11         tp = NULL;                                      \
  12         if (_skc) {                                     \
  13                 tp = bpf_skc_to_tcp_sock(_skc);         \
  14                 sk = (struct sock *)tp;                 \
  15         }                                               \
  16         tp;                                             \
  17 })
  18
  19 unsigned short reuse_listen_hport = 0;
  20 unsigned short listen_hport = 0;
  21 char cubic_cc[TCP_CA_NAME_MAX] = "bpf_cubic";
  22 char dctcp_cc[TCP_CA_NAME_MAX] = "bpf_dctcp";
  23 bool random_retry = false;
  24
  25 static bool tcp_cc_eq(const char *a, const char *b)
  26 {
  27         int i;
  28
  29         for (i = 0; i < TCP_CA_NAME_MAX; i++) {
  30                 if (a[i] != b[i])
  31                         return false;
  32                 if (!a[i])
  33                         break;
  34         }
  35
  36         return true;
  37 }
  38
  39 SEC("iter/tcp")
  40 int change_tcp_cc(struct bpf_iter__tcp *ctx)
  41 {
  42         char cur_cc[TCP_CA_NAME_MAX];
  43         struct tcp_sock *tp;
  44         struct sock *sk;
  45
  46         if (!bpf_tcp_sk(ctx->sk_common))
  47                 return 0;
  48
  49         if (sk->sk_family != AF_INET6 ||
  50             (sk->sk_state != TCP_LISTEN &&
  51              sk->sk_state != TCP_ESTABLISHED) ||
  52             (sk->sk_num != reuse_listen_hport &&
  53              sk->sk_num != listen_hport &&
  54              bpf_ntohs(sk->sk_dport) != listen_hport))
  55                 return 0;
  56
  57         if (bpf_getsockopt(tp, SOL_TCP, TCP_CONGESTION,
  58                            cur_cc, sizeof(cur_cc)))
  59                 return 0;
  60
  61         if (!tcp_cc_eq(cur_cc, cubic_cc))
  62                 return 0;
  63
  64         if (random_retry && bpf_get_prandom_u32() % 4 == 1)
  65                 return 1;
  66
  67         bpf_setsockopt(tp, SOL_TCP, TCP_CONGESTION, dctcp_cc, sizeof(dctcp_cc));
  68         return 0;
  69 }
  70
  71 char _license[] SEC("license") = "GPL";