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.
15 #include <arpa/inet.h>
19 #include <linux/unistd.h>
23 #include <sys/epoll.h>
24 #include <sys/types.h>
25 #include <sys/socket.h>
28 static const int PORT = 8888;
30 static void build_rcv_fd(int family, int proto, int *rcv_fds, int count)
32 struct sockaddr_storage addr;
33 struct sockaddr_in *addr4;
34 struct sockaddr_in6 *addr6;
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);
45 addr6 = (struct sockaddr_in6 *)&addr;
46 addr6->sin6_family = AF_INET6;
47 addr6->sin6_addr = in6addr_any;
48 addr6->sin6_port = htons(PORT);
51 error(1, 0, "Unsupported family %d", family);
54 for (i = 0; i < count; ++i) {
55 rcv_fds[i] = socket(family, proto, 0);
57 error(1, errno, "failed to create receive socket");
60 if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
62 error(1, errno, "failed to set SO_REUSEPORT");
64 if (bind(rcv_fds[i], (struct sockaddr *)&addr, sizeof(addr)))
65 error(1, errno, "failed to bind receive socket");
67 if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
68 error(1, errno, "failed to listen on receive port");
72 static void send_from_v4(int proto)
74 struct sockaddr_in saddr, daddr;
77 saddr.sin_family = AF_INET;
78 saddr.sin_addr.s_addr = htonl(INADDR_ANY);
81 daddr.sin_family = AF_INET;
82 daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
83 daddr.sin_port = htons(PORT);
85 fd = socket(AF_INET, proto, 0);
87 error(1, errno, "failed to create send socket");
89 if (bind(fd, (struct sockaddr *)&saddr, sizeof(saddr)))
90 error(1, errno, "failed to bind send socket");
92 if (connect(fd, (struct sockaddr *)&daddr, sizeof(daddr)))
93 error(1, errno, "failed to connect send socket");
95 if (send(fd, "a", 1, 0) < 0)
96 error(1, errno, "failed to send message");
101 static int receive_once(int epfd, int proto)
103 struct epoll_event ev;
107 i = epoll_wait(epfd, &ev, 1, -1);
109 error(1, errno, "epoll_wait failed");
111 if (proto == SOCK_STREAM) {
112 fd = accept(ev.data.fd, NULL, NULL);
114 error(1, errno, "failed to accept");
115 i = recv(fd, buf, sizeof(buf), 0);
118 i = recv(ev.data.fd, buf, sizeof(buf), 0);
122 error(1, errno, "failed to recv");
127 static void test(int *rcv_fds, int count, int proto)
129 struct epoll_event ev;
130 int epfd, i, test_fd;
134 epfd = epoll_create(1);
136 error(1, errno, "failed to create epoll");
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");
147 test_fd = receive_once(epfd, proto);
148 len = sizeof(test_family);
149 if (getsockopt(test_fd, SOL_SOCKET, SO_DOMAIN, &test_family, &len))
150 error(1, errno, "failed to read socket domain");
151 if (test_family != AF_INET)
152 error(1, 0, "expected to receive on v4 socket but got v6 (%d)",
162 fprintf(stderr, "---- UDP IPv4 created before IPv6 ----\n");
163 build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 5);
164 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[5]), 5);
165 test(rcv_fds, 10, SOCK_DGRAM);
166 for (i = 0; i < 10; ++i)
169 fprintf(stderr, "---- UDP IPv6 created before IPv4 ----\n");
170 build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 5);
171 build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[5]), 5);
172 test(rcv_fds, 10, SOCK_DGRAM);
173 for (i = 0; i < 10; ++i)
176 /* NOTE: UDP socket lookups traverse a different code path when there
177 * are > 10 sockets in a group.
179 fprintf(stderr, "---- UDP IPv4 created before IPv6 (large) ----\n");
180 build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 16);
181 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[16]), 16);
182 test(rcv_fds, 32, SOCK_DGRAM);
183 for (i = 0; i < 32; ++i)
186 fprintf(stderr, "---- UDP IPv6 created before IPv4 (large) ----\n");
187 build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 16);
188 build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[16]), 16);
189 test(rcv_fds, 32, SOCK_DGRAM);
190 for (i = 0; i < 32; ++i)
193 fprintf(stderr, "---- TCP IPv4 created before IPv6 ----\n");
194 build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 5);
195 build_rcv_fd(AF_INET6, SOCK_STREAM, &(rcv_fds[5]), 5);
196 test(rcv_fds, 10, SOCK_STREAM);
197 for (i = 0; i < 10; ++i)
200 fprintf(stderr, "---- TCP IPv6 created before IPv4 ----\n");
201 build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds, 5);
202 build_rcv_fd(AF_INET, SOCK_STREAM, &(rcv_fds[5]), 5);
203 test(rcv_fds, 10, SOCK_STREAM);
204 for (i = 0; i < 10; ++i)
207 fprintf(stderr, "SUCCESS\n");