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
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
|
// SPDX-License-Identifier: GPL-2.0
/* Test that sockets listening on a specific address are preferred
* over sockets listening on addr_any.
*/
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <linux/dccp.h>
#include <linux/in.h>
#include <linux/unistd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
static const char *IP4_ADDR = "127.0.0.1";
static const char *IP6_ADDR = "::1";
static const char *IP4_MAPPED6 = "::ffff:127.0.0.1";
static const int PORT = 8888;
static void build_rcv_fd(int family, int proto, int *rcv_fds, int count,
const char *addr_str)
{
struct sockaddr_in addr4 = {0};
struct sockaddr_in6 addr6 = {0};
struct sockaddr *addr;
int opt, i, sz;
memset(&addr, 0, sizeof(addr));
switch (family) {
case AF_INET:
addr4.sin_family = family;
if (!addr_str)
addr4.sin_addr.s_addr = htonl(INADDR_ANY);
else if (!inet_pton(family, addr_str, &addr4.sin_addr.s_addr))
error(1, errno, "inet_pton failed: %s", addr_str);
addr4.sin_port = htons(PORT);
sz = sizeof(addr4);
addr = (struct sockaddr *)&addr4;
break;
case AF_INET6:
addr6.sin6_family = AF_INET6;
if (!addr_str)
addr6.sin6_addr = in6addr_any;
else if (!inet_pton(family, addr_str, &addr6.sin6_addr))
error(1, errno, "inet_pton failed: %s", addr_str);
addr6.sin6_port = htons(PORT);
sz = sizeof(addr6);
addr = (struct sockaddr *)&addr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
}
for (i = 0; i < count; ++i) {
rcv_fds[i] = socket(family, proto, 0);
if (rcv_fds[i] < 0)
error(1, errno, "failed to create receive socket");
opt = 1;
if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT");
if (bind(rcv_fds[i], addr, sz))
error(1, errno, "failed to bind receive socket");
if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
error(1, errno, "tcp: failed to listen on receive port");
else if (proto == SOCK_DCCP) {
if (setsockopt(rcv_fds[i], SOL_DCCP,
DCCP_SOCKOPT_SERVICE,
&(int) {htonl(42)}, sizeof(int)))
error(1, errno, "failed to setsockopt");
if (listen(rcv_fds[i], 10))
error(1, errno, "dccp: failed to listen on receive port");
}
}
}
static int connect_and_send(int family, int proto)
{
struct sockaddr_in saddr4 = {0};
struct sockaddr_in daddr4 = {0};
struct sockaddr_in6 saddr6 = {0};
struct sockaddr_in6 daddr6 = {0};
struct sockaddr *saddr, *daddr;
int fd, sz;
switch (family) {
case AF_INET:
saddr4.sin_family = AF_INET;
saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
saddr4.sin_port = 0;
daddr4.sin_family = AF_INET;
if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
error(1, errno, "inet_pton failed: %s", IP4_ADDR);
daddr4.sin_port = htons(PORT);
sz = sizeof(saddr4);
saddr = (struct sockaddr *)&saddr4;
daddr = (struct sockaddr *)&daddr4;
break;
case AF_INET6:
saddr6.sin6_family = AF_INET6;
saddr6.sin6_addr = in6addr_any;
daddr6.sin6_family = AF_INET6;
if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
error(1, errno, "inet_pton failed: %s", IP6_ADDR);
daddr6.sin6_port = htons(PORT);
sz = sizeof(saddr6);
saddr = (struct sockaddr *)&saddr6;
daddr = (struct sockaddr *)&daddr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
}
fd = socket(family, proto, 0);
if (fd < 0)
error(1, errno, "failed to create send socket");
if (proto == SOCK_DCCP &&
setsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_SERVICE,
&(int){htonl(42)}, sizeof(int)))
error(1, errno, "failed to setsockopt");
if (bind(fd, saddr, sz))
error(1, errno, "failed to bind send socket");
if (connect(fd, daddr, sz))
error(1, errno, "failed to connect send socket");
if (send(fd, "a", 1, 0) < 0)
error(1, errno, "failed to send message");
return fd;
}
static int receive_once(int epfd, int proto)
{
struct epoll_event ev;
int i, fd;
char buf[8];
i = epoll_wait(epfd, &ev, 1, 3);
if (i < 0)
error(1, errno, "epoll_wait failed");
if (proto == SOCK_STREAM || proto == SOCK_DCCP) {
fd = accept(ev.data.fd, NULL, NULL);
if (fd < 0)
error(1, errno, "failed to accept");
i = recv(fd, buf, sizeof(buf), 0);
close(fd);
} else {
i = recv(ev.data.fd, buf, sizeof(buf), 0);
}
if (i < 0)
error(1, errno, "failed to recv");
return ev.data.fd;
}
static void test(int *rcv_fds, int count, int family, int proto, int fd)
{
struct epoll_event ev;
int epfd, i, send_fd, recv_fd;
epfd = epoll_create(1);
if (epfd < 0)
error(1, errno, "failed to create epoll");
ev.events = EPOLLIN;
for (i = 0; i < count; ++i) {
ev.data.fd = rcv_fds[i];
if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
error(1, errno, "failed to register sock epoll");
}
send_fd = connect_and_send(family, proto);
recv_fd = receive_once(epfd, proto);
if (recv_fd != fd)
error(1, 0, "received on an unexpected socket");
close(send_fd);
close(epfd);
}
static void run_one_test(int fam_send, int fam_rcv, int proto,
const char *addr_str)
{
/* Below we test that a socket listening on a specific address
* is always selected in preference over a socket listening
* on addr_any. Bugs where this is not the case often result
* in sockets created first or last to get picked. So below
* we make sure that there are always addr_any sockets created
* before and after a specific socket is created.
*/
int rcv_fds[10], i;
build_rcv_fd(AF_INET, proto, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, proto, rcv_fds + 2, 2, NULL);
build_rcv_fd(fam_rcv, proto, rcv_fds + 4, 1, addr_str);
build_rcv_fd(AF_INET, proto, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6,
|