LXR linux/tools/testing/selftests/bpf/progs/connect4

   1// SPDX-License-Identifier: GPL-2.0
   2// Copyright (c) 2018 Facebook
   3
   4#include <string.h>
   5
   6#include <linux/stddef.h>
   7#include <linux/bpf.h>
   8#include <linux/in.h>
   9#include <linux/in6.h>
  10#include <sys/socket.h>
  11
  12#include <bpf/bpf_helpers.h>
  13#include <bpf/bpf_endian.h>
  14
  15#define SRC_REWRITE_IP4         0x7f000004U
  16#define DST_REWRITE_IP4         0x7f000001U
  17#define DST_REWRITE_PORT4       4444
  18
  19int _version SEC("version") = 1;
  20
  21__attribute__ ((noinline))
  22int do_bind(struct bpf_sock_addr *ctx)
  23{
  24        struct sockaddr_in sa = {};
  25
  26        sa.sin_family = AF_INET;
  27        sa.sin_port = bpf_htons(0);
  28        sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
  29
  30        if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
  31                return 0;
  32
  33        return 1;
  34}
  35
  36SEC("cgroup/connect4")
  37int connect_v4_prog(struct bpf_sock_addr *ctx)
  38{
  39        struct bpf_sock_tuple tuple = {};
  40        struct bpf_sock *sk;
  41
  42        /* Verify that new destination is available. */
  43        memset(&tuple.ipv4.saddr, 0, sizeof(tuple.ipv4.saddr));
  44        memset(&tuple.ipv4.sport, 0, sizeof(tuple.ipv4.sport));
  45
  46        tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4);
  47        tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4);
  48
  49        if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
  50                return 0;
  51        else if (ctx->type == SOCK_STREAM)
  52                sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv4),
  53                                       BPF_F_CURRENT_NETNS, 0);
  54        else
  55                sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv4),
  56                                       BPF_F_CURRENT_NETNS, 0);
  57
  58        if (!sk)
  59                return 0;
  60
  61        if (sk->src_ip4 != tuple.ipv4.daddr ||
  62            sk->src_port != DST_REWRITE_PORT4) {
  63                bpf_sk_release(sk);
  64                return 0;
  65        }
  66
  67        bpf_sk_release(sk);
  68
  69        /* Rewrite destination. */
  70        ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
  71        ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
  72
  73        return do_bind(ctx) ? 1 : 0;
  74}
  75
  76char _license[] SEC("license") = "GPL";
  77