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