1 /* 2 * It is possible to use SO_REUSEPORT to open multiple sockets bound to 3 * equivalent local addresses using AF_INET and AF_INET6 at the same time. If 4 * the AF_INET6 socket has IPV6_V6ONLY set, it's clear which socket should 5 * receive a given incoming packet. However, when it is not set, incoming v4 6 * packets should prefer the AF_INET socket(s). This behavior was defined with 7 * the original SO_REUSEPORT implementation, but broke with 8 * e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") 9 * This test creates these mixed AF_INET/AF_INET6 sockets and asserts the 10 * AF_INET preference for v4 packets. 11 */ 12 13 #define _GNU_SOURCE 14 15 #include <arpa/inet.h> 16 #include <errno.h> 17 #include <error.h> 18 #include <linux/in.h> 19 #include <linux/unistd.h> 20 #include <stdio.h> 21 #include <stdlib.h> 22 #include <string.h> 23 #include <sys/epoll.h> 24 #include <sys/types.h> 25 #include <sys/socket.h> 26 #include <unistd.h> 27 28 static const int PORT = 8888; 29 30 static void build_rcv_fd(int family, int proto, int *rcv_fds, int count) 31 { 32 struct sockaddr_storage addr; 33 struct sockaddr_in *addr4; 34 struct sockaddr_in6 *addr6; 35 int opt, i; 36 37 switch (family) { 38 case AF_INET: 39 addr4 = (struct sockaddr_in *)&addr; 40 addr4->sin_family = AF_INET; 41 addr4->sin_addr.s_addr = htonl(INADDR_ANY); 42 addr4->sin_port = htons(PORT); 43 break; 44 case AF_INET6: 45 addr6 = (struct sockaddr_in6 *)&addr; 46 addr6->sin6_family = AF_INET6; 47 addr6->sin6_addr = in6addr_any; 48 addr6->sin6_port = htons(PORT); 49 break; 50 default: 51 error(1, 0, "Unsupported family %d", family); 52 } 53 54 for (i = 0; i < count; ++i) { 55 rcv_fds[i] = socket(family, proto, 0); 56 if (rcv_fds[i] < 0) 57 error(1, errno, "failed to create receive socket"); 58 59 opt = 1; 60 if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt, 61 sizeof(opt))) 62 error(1, errno, "failed to set SO_REUSEPORT"); 63 64 if (bind(rcv_fds[i], (struct sockaddr *)&addr, sizeof(addr))) 65 error(1, errno, "failed to bind receive socket"); 66 67 if (proto == SOCK_STREAM && listen(rcv_fds[i], 10)) 68 error(1, errno, "failed to listen on receive port"); 69 } 70 } 71 72 static void send_from_v4(int proto) 73 { 74 struct sockaddr_in saddr, daddr; 75 int fd; 76 77 saddr.sin_family = AF_INET; 78 saddr.sin_addr.s_addr = htonl(INADDR_ANY); 79 saddr.sin_port = 0; 80 81 daddr.sin_family = AF_INET; 82 daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); 83 daddr.sin_port = htons(PORT); 84 85 fd = socket(AF_INET, proto, 0); 86 if (fd < 0) 87 error(1, errno, "failed to create send socket"); 88 89 if (bind(fd, (struct sockaddr *)&saddr, sizeof(saddr))) 90 error(1, errno, "failed to bind send socket"); 91 92 if (connect(fd, (struct sockaddr *)&daddr, sizeof(daddr))) 93 error(1, errno, "failed to connect send socket"); 94 95 if (send(fd, "a", 1, 0) < 0) 96 error(1, errno, "failed to send message"); 97 98 close(fd); 99 } 100 101 static int receive_once(int epfd, int proto) 102 { 103 struct epoll_event ev; 104 int i, fd; 105 char buf[8]; 106 107 i = epoll_wait(epfd, &ev, 1, -1); 108 if (i < 0) 109 error(1, errno, "epoll_wait failed"); 110 111 if (proto == SOCK_STREAM) { 112 fd = accept(ev.data.fd, NULL, NULL); 113 if (fd < 0) 114 error(1, errno, "failed to accept"); 115 i = recv(fd, buf, sizeof(buf), 0); 116 close(fd); 117 } else { 118 i = recv(ev.data.fd, buf, sizeof(buf), 0); 119 } 120 121 if (i < 0) 122 error(1, errno, "failed to recv"); 123 124 return ev.data.fd; 125 } 126 127 static void test(int *rcv_fds, int count, int proto) 128 { 129 struct epoll_event ev; 130 int epfd, i, test_fd; 131 uint16_t test_family; 132 socklen_t len; 133 134 epfd = epoll_create(1); 135 if (epfd < 0) 136 error(1, errno, "failed to create epoll"); 137 138 ev.events = EPOLLIN; 139 for (i = 0; i < count; ++i) { 140 ev.data.fd = rcv_fds[i]; 141 if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev)) 142 error(1, errno, "failed to register sock epoll"); 143 } 144 145 send_from_v4(proto); 146 147 test_fd = receive_once(epfd, proto); 148 if (getsockopt(test_fd, SOL_SOCKET, SO_DOMAIN, &test_family, &len)) 149 error(1, errno, "failed to read socket domain"); 150 if (test_family != AF_INET) 151 error(1, 0, "expected to receive on v4 socket but got v6 (%d)", 152 test_family); 153 154 close(epfd); 155 } 156 157 int main(void) 158 { 159 int rcv_fds[32], i; 160 161 fprintf(stderr, "---- UDP IPv4 created before IPv6 ----\n"); 162 build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 5); 163 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[5]), 5); 164 test(rcv_fds, 10, SOCK_DGRAM); 165 for (i = 0; i < 10; ++i) 166 close(rcv_fds[i]); 167 168 fprintf(stderr, "---- UDP IPv6 created before IPv4 ----\n"); 169 build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 5); 170 build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[5]), 5); 171 test(rcv_fds, 10, SOCK_DGRAM); 172 for (i = 0; i < 10; ++i) 173 close(rcv_fds[i]); 174 175 /* NOTE: UDP socket lookups traverse a different code path when there 176 * are > 10 sockets in a group. 177 */ 178 fprintf(stderr, "---- UDP IPv4 created before IPv6 (large) ----\n"); 179 build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 16); 180 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[16]), 16); 181 test(rcv_fds, 32, SOCK_DGRAM); 182 for (i = 0; i < 32; ++i) 183 close(rcv_fds[i]); 184 185 fprintf(stderr, "---- UDP IPv6 created before IPv4 (large) ----\n"); 186 build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 16); 187 build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[16]), 16); 188 test(rcv_fds, 32, SOCK_DGRAM); 189 for (i = 0; i < 32; ++i) 190 close(rcv_fds[i]); 191 192 fprintf(stderr, "---- TCP IPv4 created before IPv6 ----\n"); 193 build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 5); 194 build_rcv_fd(AF_INET6, SOCK_STREAM, &(rcv_fds[5]), 5); 195 test(rcv_fds, 10, SOCK_STREAM); 196 for (i = 0; i < 10; ++i) 197 close(rcv_fds[i]); 198 199 fprintf(stderr, "---- TCP IPv6 created before IPv4 ----\n"); 200 build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds, 5); 201 build_rcv_fd(AF_INET, SOCK_STREAM, &(rcv_fds[5]), 5); 202 test(rcv_fds, 10, SOCK_STREAM); 203 for (i = 0; i < 10; ++i) 204 close(rcv_fds[i]); 205 206 fprintf(stderr, "SUCCESS\n"); 207 return 0; 208 } 209