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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
   3
   4 #include "vmlinux.h"
   5
   6 #include <string.h>
   7 #include <bpf/bpf_helpers.h>
   8 #include <bpf/bpf_core_read.h>
   9 #include "bpf_kfuncs.h"
  10
  11 __u8 SERVUN_REWRITE_ADDRESS[] = "\0bpf_cgroup_unix_test_rewrite";
  12
  13 SEC("cgroup/sendmsg_unix")
  14 int sendmsg_unix_prog(struct bpf_sock_addr *ctx)
  15 {
  16         struct bpf_sock_addr_kern *sa_kern = bpf_cast_to_kern_ctx(ctx);
  17         struct sockaddr_un *sa_kern_unaddr;
  18         __u32 unaddrlen = offsetof(struct sockaddr_un, sun_path) +
  19                           sizeof(SERVUN_REWRITE_ADDRESS) - 1;
  20         int ret;
  21
  22         /* Rewrite destination. */
  23         ret = bpf_sock_addr_set_sun_path(sa_kern, SERVUN_REWRITE_ADDRESS,
  24                                          sizeof(SERVUN_REWRITE_ADDRESS) - 1);
  25         if (ret)
  26                 return 0;
  27
  28         if (sa_kern->uaddrlen != unaddrlen)
  29                 return 0;
  30
  31         sa_kern_unaddr = bpf_core_cast(sa_kern->uaddr, struct sockaddr_un);
  32         if (memcmp(sa_kern_unaddr->sun_path, SERVUN_REWRITE_ADDRESS,
  33                         sizeof(SERVUN_REWRITE_ADDRESS) - 1) != 0)
  34                 return 0;
  35
  36         return 1;
  37 }
  38
  39 SEC("cgroup/sendmsg_unix")
  40 int sendmsg_unix_deny_prog(struct bpf_sock_addr *ctx)
  41 {
  42         return 0;
  43 }
  44
  45 char _license[] SEC("license") = "GPL";