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_helpers.h"
13#include "bpf_endian.h"
14
15#define SRC_REWRITE_IP6_0	0
16#define SRC_REWRITE_IP6_1	0
17#define SRC_REWRITE_IP6_2	0
18#define SRC_REWRITE_IP6_3	6
19
20#define DST_REWRITE_IP6_0	0
21#define DST_REWRITE_IP6_1	0
22#define DST_REWRITE_IP6_2	0
23#define DST_REWRITE_IP6_3	1
24
25#define DST_REWRITE_PORT6	6666
26
27int _version SEC("version") = 1;
28
29SEC("cgroup/connect6")
30int connect_v6_prog(struct bpf_sock_addr *ctx)
31{
32	struct sockaddr_in6 sa;
33
34	/* Rewrite destination. */
35	ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
36	ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
37	ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
38	ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);
39
40	ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
41
42	if (ctx->type == SOCK_DGRAM || ctx->type == SOCK_STREAM) {
43		/* Rewrite source. */
44		memset(&sa, 0, sizeof(sa));
45
46		sa.sin6_family = AF_INET6;
47		sa.sin6_port = bpf_htons(0);
48
49		sa.sin6_addr.s6_addr32[0] = bpf_htonl(SRC_REWRITE_IP6_0);
50		sa.sin6_addr.s6_addr32[1] = bpf_htonl(SRC_REWRITE_IP6_1);
51		sa.sin6_addr.s6_addr32[2] = bpf_htonl(SRC_REWRITE_IP6_2);
52		sa.sin6_addr.s6_addr32[3] = bpf_htonl(SRC_REWRITE_IP6_3);
53
54		if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
55			return 0;
56	}
57
58	return 1;
59}
60
61char _license[] SEC("license") = "GPL";