tools/testing/selftests/bpf/progs/sendmsg6_prog.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018 Facebook
   3
   4 #include <linux/stddef.h>
   5 #include <linux/bpf.h>
   6 #include <sys/socket.h>
   7
   8 #include <bpf/bpf_helpers.h>
   9 #include <bpf/bpf_endian.h>
  10
  11 #include <bpf_sockopt_helpers.h>
  12
  13 #define SRC_REWRITE_IP6_0       0
  14 #define SRC_REWRITE_IP6_1       0
  15 #define SRC_REWRITE_IP6_2       0
  16 #define SRC_REWRITE_IP6_3       6
  17
  18 #define DST_REWRITE_IP6_0       0
  19 #define DST_REWRITE_IP6_1       0
  20 #define DST_REWRITE_IP6_2       0
  21 #define DST_REWRITE_IP6_3       1
  22
  23 #define DST_REWRITE_IP6_V4_MAPPED_0     0
  24 #define DST_REWRITE_IP6_V4_MAPPED_1     0
  25 #define DST_REWRITE_IP6_V4_MAPPED_2     0x0000FFFF
  26 #define DST_REWRITE_IP6_V4_MAPPED_3     0xc0a80004 // 192.168.0.4
  27
  28 #define DST_REWRITE_PORT6       6666
  29
  30 SEC("cgroup/sendmsg6")
  31 int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
  32 {
  33         if (ctx->type != SOCK_DGRAM)
  34                 return 0;
  35
  36         if (!get_set_sk_priority(ctx))
  37                 return 0;
  38
  39         /* Rewrite source. */
  40         if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||
  41             ctx->msg_src_ip6[3] == bpf_htonl(0)) {
  42                 ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
  43                 ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
  44                 ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
  45                 ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
  46         } else {
  47                 /* Unexpected source. Reject sendmsg. */
  48                 return 0;
  49         }
  50
  51         /* Rewrite destination. */
  52         if (ctx->user_ip6[0] == bpf_htonl(0xFACEB00C)) {
  53                 ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
  54                 ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
  55                 ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
  56                 ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);
  57
  58                 ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
  59         } else {
  60                 /* Unexpected destination. Reject sendmsg. */
  61                 return 0;
  62         }
  63
  64         return 1;
  65 }
  66
  67 SEC("cgroup/sendmsg6")
  68 int sendmsg_v6_v4mapped_prog(struct bpf_sock_addr *ctx)
  69 {
  70         /* Rewrite source. */
  71         ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
  72         ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
  73         ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
  74         ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
  75
  76         /* Rewrite destination. */
  77         ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_V4_MAPPED_0);
  78         ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_V4_MAPPED_1);
  79         ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_V4_MAPPED_2);
  80         ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_V4_MAPPED_3);
  81
  82         ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
  83
  84         return 1;
  85 }
  86
  87 SEC("cgroup/sendmsg6")
  88 int sendmsg_v6_wildcard_prog(struct bpf_sock_addr *ctx)
  89 {
  90         /* Rewrite source. */
  91         ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
  92         ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
  93         ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
  94         ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
  95
  96         /* Rewrite destination. */
  97         ctx->user_ip6[0] = bpf_htonl(0);
  98         ctx->user_ip6[1] = bpf_htonl(0);
  99         ctx->user_ip6[2] = bpf_htonl(0);
 100         ctx->user_ip6[3] = bpf_htonl(0);
 101
 102         ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
 103
 104         return 1;
 105 }
 106
 107 SEC("cgroup/sendmsg6")
 108 int sendmsg_v6_preserve_dst_prog(struct bpf_sock_addr *ctx)
 109 {
 110         return 1;
 111 }
 112
 113 SEC("cgroup/sendmsg6")
 114 int sendmsg_v6_deny_prog(struct bpf_sock_addr *ctx)
 115 {
 116         return 0;
 117 }
 118
 119 char _license[] SEC("license") = "GPL";