tools/testing/selftests/bpf/progs/bind6_prog.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <string.h>
   4
   5 #include <linux/stddef.h>
   6 #include <linux/bpf.h>
   7 #include <linux/in.h>
   8 #include <linux/in6.h>
   9 #include <sys/socket.h>
  10 #include <netinet/tcp.h>
  11 #include <linux/if.h>
  12 #include <errno.h>
  13
  14 #include <bpf/bpf_helpers.h>
  15 #include <bpf/bpf_endian.h>
  16
  17 #define SERV6_IP_0              0xfaceb00c /* face:b00c:1234:5678::abcd */
  18 #define SERV6_IP_1              0x12345678
  19 #define SERV6_IP_2              0x00000000
  20 #define SERV6_IP_3              0x0000abcd
  21 #define SERV6_PORT              6060
  22 #define SERV6_REWRITE_IP_0      0x00000000
  23 #define SERV6_REWRITE_IP_1      0x00000000
  24 #define SERV6_REWRITE_IP_2      0x00000000
  25 #define SERV6_REWRITE_IP_3      0x00000001
  26 #define SERV6_REWRITE_PORT      6666
  27
  28 #ifndef IFNAMSIZ
  29 #define IFNAMSIZ 16
  30 #endif
  31
  32 static __inline int bind_to_device(struct bpf_sock_addr *ctx)
  33 {
  34         char veth1[IFNAMSIZ] = "test_sock_addr1";
  35         char veth2[IFNAMSIZ] = "test_sock_addr2";
  36         char missing[IFNAMSIZ] = "nonexistent_dev";
  37         char del_bind[IFNAMSIZ] = "";
  38
  39         if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
  40                                 &veth1, sizeof(veth1)))
  41                 return 1;
  42         if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
  43                                 &veth2, sizeof(veth2)))
  44                 return 1;
  45         if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
  46                                 &missing, sizeof(missing)) != -ENODEV)
  47                 return 1;
  48         if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
  49                                 &del_bind, sizeof(del_bind)))
  50                 return 1;
  51
  52         return 0;
  53 }
  54
  55 SEC("cgroup/bind6")
  56 int bind_v6_prog(struct bpf_sock_addr *ctx)
  57 {
  58         struct bpf_sock *sk;
  59         __u32 user_ip6;
  60         __u16 user_port;
  61         int i;
  62
  63         sk = ctx->sk;
  64         if (!sk)
  65                 return 0;
  66
  67         if (sk->family != AF_INET6)
  68                 return 0;
  69
  70         if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
  71                 return 0;
  72
  73         if (ctx->user_ip6[0] != bpf_htonl(SERV6_IP_0) ||
  74             ctx->user_ip6[1] != bpf_htonl(SERV6_IP_1) ||
  75             ctx->user_ip6[2] != bpf_htonl(SERV6_IP_2) ||
  76             ctx->user_ip6[3] != bpf_htonl(SERV6_IP_3) ||
  77             ctx->user_port != bpf_htons(SERV6_PORT))
  78                 return 0;
  79
  80         // u8 narrow loads:
  81         for (i = 0; i < 4; i++) {
  82                 user_ip6 = 0;
  83                 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[0] << 0;
  84                 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[1] << 8;
  85                 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[2] << 16;
  86                 user_ip6 |= ((volatile __u8 *)&ctx->user_ip6[i])[3] << 24;
  87                 if (ctx->user_ip6[i] != user_ip6)
  88                         return 0;
  89         }
  90
  91         user_port = 0;
  92         user_port |= ((volatile __u8 *)&ctx->user_port)[0] << 0;
  93         user_port |= ((volatile __u8 *)&ctx->user_port)[1] << 8;
  94         if (ctx->user_port != user_port)
  95                 return 0;
  96
  97         // u16 narrow loads:
  98         for (i = 0; i < 4; i++) {
  99                 user_ip6 = 0;
 100                 user_ip6 |= ((volatile __u16 *)&ctx->user_ip6[i])[0] << 0;
 101                 user_ip6 |= ((volatile __u16 *)&ctx->user_ip6[i])[1] << 16;
 102                 if (ctx->user_ip6[i] != user_ip6)
 103                         return 0;
 104         }
 105
 106         /* Bind to device and unbind it. */
 107         if (bind_to_device(ctx))
 108                 return 0;
 109
 110         ctx->user_ip6[0] = bpf_htonl(SERV6_REWRITE_IP_0);
 111         ctx->user_ip6[1] = bpf_htonl(SERV6_REWRITE_IP_1);
 112         ctx->user_ip6[2] = bpf_htonl(SERV6_REWRITE_IP_2);
 113         ctx->user_ip6[3] = bpf_htonl(SERV6_REWRITE_IP_3);
 114         ctx->user_port = bpf_htons(SERV6_REWRITE_PORT);
 115
 116         return 1;
 117 }
 118
 119 char _license[] SEC("license") = "GPL";