1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <string.h>
#include <linux/stddef.h>
#include <linux/bpf.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/tcp.h>
#include <linux/if.h>
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#include "bpf_tcp_helpers.h"
#define SRC_REWRITE_IP4 0x7f000004U
#define DST_REWRITE_IP4 0x7f000001U
#define DST_REWRITE_PORT4 4444
#ifndef TCP_CA_NAME_MAX
#define TCP_CA_NAME_MAX 16
#endif
#ifndef TCP_NOTSENT_LOWAT
#define TCP_NOTSENT_LOWAT 25
#endif
#ifndef IFNAMSIZ
#define IFNAMSIZ 16
#endif
__attribute__ ((noinline)) __weak
int do_bind(struct bpf_sock_addr *ctx)
{
struct sockaddr_in sa = {};
sa.sin_family = AF_INET;
sa.sin_port = bpf_htons(0);
sa.sin_addr.s_addr = bpf_htonl(SRC_REWRITE_IP4);
if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
return 0;
return 1;
}
static __inline int verify_cc(struct bpf_sock_addr *ctx,
char expected[TCP_CA_NAME_MAX])
{
char buf[TCP_CA_NAME_MAX];
int i;
if (bpf_getsockopt(ctx, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf)))
return 1;
for (i = 0; i < TCP_CA_NAME_MAX; i++) {
if (buf[i] != expected[i])
return 1;
if (buf[i] == 0)
break;
}
return 0;
}
static __inline int set_cc(struct bpf_sock_addr *ctx)
{
char reno[TCP_CA_NAME_MAX] = "reno";
char cubic[TCP_CA_NAME_MAX] = "cubic";
if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &reno, sizeof(reno)))
return 1;
if (verify_cc(ctx, reno))
return 1;
if (bpf_setsockopt(ctx, SOL_TCP, TCP_CONGESTION, &cubic, sizeof(cubic)))
return 1;
if (verify_cc(ctx, cubic))
return 1;
return 0;
}
static __inline int bind_to_device(struct bpf_sock_addr *ctx)
{
char veth1[IFNAMSIZ] = "test_sock_addr1";
char veth2[IFNAMSIZ] = "test_sock_addr2";
char missing[IFNAMSIZ] = "nonexistent_dev";
char del_bind[IFNAMSIZ] = "";
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
&veth1, sizeof(veth1)))
return 1;
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
&veth2, sizeof(veth2)))
return 1;
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
&missing, sizeof(missing)) != -ENODEV)
return 1;
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_BINDTODEVICE,
&del_bind, sizeof(del_bind)))
return 1;
return 0;
}
static __inline int set_keepalive(struct bpf_sock_addr *ctx)
{
int zero = 0, one = 1;
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof(one)))
return 1;
if (ctx->type == SOCK_STREAM) {
if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPIDLE, &one, sizeof(one)))
return 1;
if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPINTVL, &one, sizeof(one)))
return 1;
if (bpf_setsockopt(ctx, SOL_TCP, TCP_KEEPCNT, &one, sizeof(one)))
return 1;
if (bpf_setsockopt(ctx, SOL_TCP, TCP_SYNCNT, &one, sizeof(one)))
return 1;
if (bpf_setsockopt(ctx, SOL_TCP, TCP_USER_TIMEOUT, &one, sizeof(one)))
return 1;
}
if (bpf_setsockopt(ctx, SOL_SOCKET, SO_KEEPALIVE, &zero, sizeof(zero)))
return 1;
return 0;
}
static __inline int set_notsent_lowat(struct bpf_sock_addr *ctx)
{
int lowat = 65535;
if (ctx->type == SOCK_STREAM) {
if (bpf_setsockopt(ctx, SOL_TCP, TCP_NOTSENT_LOWAT, &lowat, sizeof(lowat)))
return 1;
}
return 0;
}
SEC("cgroup/connect4")
int connect_v4_prog(struct bpf_sock_addr *ctx)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
/* Verify that new destination is available. */
memset(&tuple.ipv4.saddr, 0, sizeof(tuple.ipv4.saddr));
memset(&tuple.ipv4.sport, 0, sizeof(tuple.ipv4.sport));
tuple.ipv4.daddr = bpf_htonl(DST_REWRITE_IP4);
tuple.ipv4.dport = bpf_htons(DST_REWRITE_PORT4);
/* Bind to device and unbind it. */
if (bind_to_device(ctx))
return 0;
if (set_keepalive(ctx))
return 0;
if (set_notsent_lowat(ctx))
return 0;
if (ctx->type != SOCK_STREAM && ctx->type != SOCK_DGRAM)
return 0;
else if (ctx->type == SOCK_STREAM)
sk = bpf_sk_lookup_tcp(ctx, &tuple, sizeof(tuple.ipv4),
BPF_F_CURRENT_NETNS, 0);
else
sk = bpf_sk_lookup_udp(ctx, &tuple, sizeof(tuple.ipv4),
BPF_F_CURRENT_NETNS, 0);
if (!sk)
return 0;
if (sk->src_ip4 != tuple.ipv4.daddr ||
sk->src_port != DST_REWRITE_PORT4) {
bpf_sk_release(sk);
return 0;
}
bpf_sk_release(sk);
/* Rewrite congestion control. */
if (ctx->type == SOCK_STREAM && set_cc(ctx))
return 0;
/* Rewrite destination. */
ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
return do_bind(ctx) ? 1 : 0;
}
char _license[] SEC("license") = "GPL";
|
