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
28static const char *IP4_ADDR = "127.0.0.1";
29static const char *IP6_ADDR = "::1";
30static const char *IP4_MAPPED6 = "::ffff:127.0.0.1";
31
32static const int PORT = 8888;
33
34static 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
101static 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
168static 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
194static 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
221static 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
244static 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
270int 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