1 // SPDX-License-Identifier: GPL-2.0
2
3 /* Test that sockets listening on a specific address are preferred
4 * over sockets listening on addr_any.
5 */
6
7 #define _GNU_SOURCE
8
9 #include <arpa/inet.h>
10 #include <errno.h>
11 #include <error.h>
12 #include <linux/dccp.h>
13 #include <linux/in.h>
14 #include <linux/unistd.h>
15 #include <stdbool.h>
16 #include <stdio.h>
17 #include <stdlib.h>
18 #include <string.h>
19 #include <sys/epoll.h>
20 #include <sys/types.h>
21 #include <sys/socket.h>
22 #include <unistd.h>
23
24 #ifndef SOL_DCCP
25 #define SOL_DCCP 269
26 #endif
27
28 static const char *IP4_ADDR = "127.0.0.1";
29 static const char *IP6_ADDR = "::1";
30 static const char *IP4_MAPPED6 = "::ffff:127.0.0.1";
31
32 static const int PORT = 8888;
33
34 static void build_rcv_fd(int family, int proto, int *rcv_fds, int count,
35 const char *addr_str)
36 {
37 struct sockaddr_in addr4 = {0};
38 struct sockaddr_in6 addr6 = {0};
39 struct sockaddr *addr;
40 int opt, i, sz;
41
42 memset(&addr, 0, sizeof(addr));
43
44 switch (family) {
45 case AF_INET:
46 addr4.sin_family = family;
47 if (!addr_str)
48 addr4.sin_addr.s_addr = htonl(INADDR_ANY);
49 else if (!inet_pton(family, addr_str, &addr4.sin_addr.s_addr))
50 error(1, errno, "inet_pton failed: %s", addr_str);
51 addr4.sin_port = htons(PORT);
52 sz = sizeof(addr4);
53 addr = (struct sockaddr *)&addr4;
54 break;
55 case AF_INET6:
56 addr6.sin6_family = AF_INET6;
57 if (!addr_str)
58 addr6.sin6_addr = in6addr_any;
59 else if (!inet_pton(family, addr_str, &addr6.sin6_addr))
60 error(1, errno, "inet_pton failed: %s", addr_str);
61 addr6.sin6_port = htons(PORT);
62 sz = sizeof(addr6);
63 addr = (struct sockaddr *)&addr6;
64 break;
65 default:
66 error(1, 0, "Unsupported family %d", family);
67 /* clang does not recognize error() above as terminating
68 * the program, so it complains that saddr, sz are
69 * not initialized when this code path is taken. Silence it.
70 */
71 return;
72 }
73
74 for (i = 0; i < count; ++i) {
75 rcv_fds[i] = socket(family, proto, 0);
76 if (rcv_fds[i] < 0)
77 error(1, errno, "failed to create receive socket");
78
79 opt = 1;
80 if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
81 sizeof(opt)))
82 error(1, errno, "failed to set SO_REUSEPORT");
83
84 if (bind(rcv_fds[i], addr, sz))
85 error(1, errno, "failed to bind receive socket");
86
87 if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
88 error(1, errno, "tcp: failed to listen on receive port");
89 else if (proto == SOCK_DCCP) {
90 if (setsockopt(rcv_fds[i], SOL_DCCP,
91 DCCP_SOCKOPT_SERVICE,
92 &(int) {htonl(42)}, sizeof(int)))
93 error(1, errno, "failed to setsockopt");
94
95 if (listen(rcv_fds[i], 10))
96 error(1, errno, "dccp: failed to listen on receive port");
97 }
98 }
99 }
100
101 static int connect_and_send(int family, int proto)
102 {
103 struct sockaddr_in saddr4 = {0};
104 struct sockaddr_in daddr4 = {0};
105 struct sockaddr_in6 saddr6 = {0};
106 struct sockaddr_in6 daddr6 = {0};
107 struct sockaddr *saddr, *daddr;
108 int fd, sz;
109
110 switch (family) {
111 case AF_INET:
112 saddr4.sin_family = AF_INET;
113 saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
114 saddr4.sin_port = 0;
115
116 daddr4.sin_family = AF_INET;
117 if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
118 error(1, errno, "inet_pton failed: %s", IP4_ADDR);
119 daddr4.sin_port = htons(PORT);
120
121 sz = sizeof(saddr4);
122 saddr = (struct sockaddr *)&saddr4;
123 daddr = (struct sockaddr *)&daddr4;
124 break;
125 case AF_INET6:
126 saddr6.sin6_family = AF_INET6;
127 saddr6.sin6_addr = in6addr_any;
128
129 daddr6.sin6_family = AF_INET6;
130 if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
131 error(1, errno, "inet_pton failed: %s", IP6_ADDR);
132 daddr6.sin6_port = htons(PORT);
133
134 sz = sizeof(saddr6);
135 saddr = (struct sockaddr *)&saddr6;
136 daddr = (struct sockaddr *)&daddr6;
137 break;
138 default:
139 error(1, 0, "Unsupported family %d", family);
140 /* clang does not recognize error() above as terminating
141 * the program, so it complains that saddr, daddr, sz are
142 * not initialized when this code path is taken. Silence it.
143 */
144 return -1;
145 }
146
147 fd = socket(family, proto, 0);
148 if (fd < 0)
149 error(1, errno, "failed to create send socket");
150
151 if (proto == SOCK_DCCP &&
152 setsockopt(fd, SOL_DCCP, DCCP_SOCKOPT_SERVICE,
153 &(int){htonl(42)}, sizeof(int)))
154 error(1, errno, "failed to setsockopt");
155
156 if (bind(fd, saddr, sz))
157 error(1, errno, "failed to bind send socket");
158
159 if (connect(fd, daddr, sz))
160 error(1, errno, "failed to connect send socket");
161
162 if (send(fd, "a", 1, 0) < 0)
163 error(1, errno, "failed to send message");
164
165 return fd;
166 }
167
168 static int receive_once(int epfd, int proto)
169 {
170 struct epoll_event ev;
171 int i, fd;
172 char buf[8];
173
174 i = epoll_wait(epfd, &ev, 1, 3);
175 if (i < 0)
176 error(1, errno, "epoll_wait failed");
177
178 if (proto == SOCK_STREAM || proto == SOCK_DCCP) {
179 fd = accept(ev.data.fd, NULL, NULL);
180 if (fd < 0)
181 error(1, errno, "failed to accept");
182 i = recv(fd, buf, sizeof(buf), 0);
183 close(fd);
184 } else {
185 i = recv(ev.data.fd, buf, sizeof(buf), 0);
186 }
187
188 if (i < 0)
189 error(1, errno, "failed to recv");
190
191 return ev.data.fd;
192 }
193
194 static void test(int *rcv_fds, int count, int family, int proto, int fd)
195 {
196 struct epoll_event ev;
197 int epfd, i, send_fd, recv_fd;
198
199 epfd = epoll_create(1);
200 if (epfd < 0)
201 error(1, errno, "failed to create epoll");
202
203 ev.events = EPOLLIN;
204 for (i = 0; i < count; ++i) {
205 ev.data.fd = rcv_fds[i];
206 if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
207 error(1, errno, "failed to register sock epoll");
208 }
209
210 send_fd = connect_and_send(family, proto);
211
212 recv_fd = receive_once(epfd, proto);
213 if (recv_fd != fd)
214 error(1, 0, "received on an unexpected socket");
215
216 close(send_fd);
217 close(epfd);
218 }
219
220
221 static void run_one_test(int fam_send, int fam_rcv, int proto,
222 const char *addr_str)
223 {
224 /* Below we test that a socket listening on a specific address
225 * is always selected in preference over a socket listening
226 * on addr_any. Bugs where this is not the case often result
227 * in sockets created first or last to get picked. So below
228 * we make sure that there are always addr_any sockets created
229 * before and after a specific socket is created.
230 */
231 int rcv_fds[10], i;
232
233 build_rcv_fd(AF_INET, proto, rcv_fds, 2, NULL);
234 build_rcv_fd(AF_INET6, proto, rcv_fds + 2, 2, NULL);
235 build_rcv_fd(fam_rcv, proto, rcv_fds + 4, 1, addr_str);
236 build_rcv_fd(AF_INET, proto, rcv_fds + 5, 2, NULL);
237 build_rcv_fd(AF_INET6, proto, rcv_fds + 7, 2, NULL);
238 test(rcv_fds, 9, fam_send, proto, rcv_fds[4]);
239 for (i = 0; i < 9; ++i)
240 close(rcv_fds[i]);
241 fprintf(stderr, "pass\n");
242 }
243
244 static void test_proto(int proto, const char *proto_str)
245 {
246 if (proto == SOCK_DCCP) {
247 int test_fd;
248
249 test_fd = socket(AF_INET, proto, 0);
250 if (test_fd < 0) {
251 if (errno == ESOCKTNOSUPPORT) {
252 fprintf(stderr, "DCCP not supported: skipping DCCP tests\n");
253 return;
254 } else
255 error(1, errno, "failed to create a DCCP socket");
256 }
257 close(test_fd);
258 }
259
260 fprintf(stderr, "%s IPv4 ... ", proto_str);
261 run_one_test(AF_INET, AF_INET, proto, IP4_ADDR);
262
263 fprintf(stderr, "%s IPv6 ... ", proto_str);
264 run_one_test(AF_INET6, AF_INET6, proto, IP6_ADDR);
265
266 fprintf(stderr, "%s IPv4 mapped to IPv6 ... ", proto_str);
267 run_one_test(AF_INET, AF_INET6, proto, IP4_MAPPED6);
268 }
269
270 int main(void)
271 {
272 test_proto(SOCK_DGRAM, "UDP");
273 test_proto(SOCK_STREAM, "TCP");
274 test_proto(SOCK_DCCP, "DCCP");
275
276 fprintf(stderr, "SUCCESS\n");
277 return 0;
278 }
279
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