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 
build_rcv_fd(int family,int proto,int * rcv_fds,int count,const char * addr_str)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 
connect_and_send(int family,int proto)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 
receive_once(int epfd,int proto)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 
test(int * rcv_fds,int count,int family,int proto,int fd)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 
run_one_test(int fam_send,int fam_rcv,int proto,const char * addr_str)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 
test_proto(int proto,const char * proto_str)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 
main(void)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