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#define SRC_REWRITE_IP6_0	0
12#define SRC_REWRITE_IP6_1	0
13#define SRC_REWRITE_IP6_2	0
14#define SRC_REWRITE_IP6_3	6
15
16#define DST_REWRITE_IP6_0	0
17#define DST_REWRITE_IP6_1	0
18#define DST_REWRITE_IP6_2	0
19#define DST_REWRITE_IP6_3	1
20
21#define DST_REWRITE_PORT6	6666
22
23int _version SEC("version") = 1;
24
25SEC("cgroup/sendmsg6")
26int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
27{
28	if (ctx->type != SOCK_DGRAM)
 
 
 
29		return 0;
30
31	/* Rewrite source. */
32	if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||
33	    ctx->msg_src_ip6[3] == bpf_htonl(0)) {
34		ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
35		ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
36		ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
37		ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
38	} else {
39		/* Unexpected source. Reject sendmsg. */
40		return 0;
41	}
42
43	/* Rewrite destination. */
44	if (ctx->user_ip6[0] == bpf_htonl(0xFACEB00C)) {
45		ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
46		ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
47		ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
48		ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);
49
50		ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
51	} else {
52		/* Unexpected destination. Reject sendmsg. */
53		return 0;
54	}
55
56	return 1;
57}
58
59char _license[] SEC("license") = "GPL";

 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_PORT6	6666
24
 
 
25SEC("cgroup/sendmsg6")
26int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
27{
28	if (ctx->type != SOCK_DGRAM)
29		return 0;
30
31	if (!get_set_sk_priority(ctx))
32		return 0;
33
34	/* Rewrite source. */
35	if (ctx->msg_src_ip6[3] == bpf_htonl(1) ||
36	    ctx->msg_src_ip6[3] == bpf_htonl(0)) {
37		ctx->msg_src_ip6[0] = bpf_htonl(SRC_REWRITE_IP6_0);
38		ctx->msg_src_ip6[1] = bpf_htonl(SRC_REWRITE_IP6_1);
39		ctx->msg_src_ip6[2] = bpf_htonl(SRC_REWRITE_IP6_2);
40		ctx->msg_src_ip6[3] = bpf_htonl(SRC_REWRITE_IP6_3);
41	} else {
42		/* Unexpected source. Reject sendmsg. */
43		return 0;
44	}
45
46	/* Rewrite destination. */
47	if (ctx->user_ip6[0] == bpf_htonl(0xFACEB00C)) {
48		ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
49		ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
50		ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
51		ctx->user_ip6[3] = bpf_htonl(DST_REWRITE_IP6_3);
52
53		ctx->user_port = bpf_htons(DST_REWRITE_PORT6);
54	} else {
55		/* Unexpected destination. Reject sendmsg. */
56		return 0;
57	}
58
59	return 1;
60}
61
62char _license[] SEC("license") = "GPL";