1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * It is possible to use SO_REUSEPORT to open multiple sockets bound to |
4 | * equivalent local addresses using AF_INET and AF_INET6 at the same time. If |
5 | * the AF_INET6 socket has IPV6_V6ONLY set, it's clear which socket should |
6 | * receive a given incoming packet. However, when it is not set, incoming v4 |
7 | * packets should prefer the AF_INET socket(s). This behavior was defined with |
8 | * the original SO_REUSEPORT implementation, but broke with |
9 | * e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection") |
10 | * This test creates these mixed AF_INET/AF_INET6 sockets and asserts the |
11 | * AF_INET preference for v4 packets. |
12 | */ |
13 | |
14 | #define _GNU_SOURCE |
15 | |
16 | #include <arpa/inet.h> |
17 | #include <errno.h> |
18 | #include <error.h> |
19 | #include <linux/in.h> |
20 | #include <linux/unistd.h> |
21 | #include <stdio.h> |
22 | #include <stdlib.h> |
23 | #include <string.h> |
24 | #include <sys/epoll.h> |
25 | #include <sys/types.h> |
26 | #include <sys/socket.h> |
27 | #include <unistd.h> |
28 | |
29 | static const int PORT = 8888; |
30 | |
31 | static void build_rcv_fd(int family, int proto, int *rcv_fds, int count) |
32 | { |
33 | struct sockaddr_storage addr; |
34 | struct sockaddr_in *addr4; |
35 | struct sockaddr_in6 *addr6; |
36 | int opt, i; |
37 | |
38 | switch (family) { |
39 | case AF_INET: |
40 | addr4 = (struct sockaddr_in *)&addr; |
41 | addr4->sin_family = AF_INET; |
42 | addr4->sin_addr.s_addr = htonl(INADDR_ANY); |
43 | addr4->sin_port = htons(PORT); |
44 | break; |
45 | case AF_INET6: |
46 | addr6 = (struct sockaddr_in6 *)&addr; |
47 | addr6->sin6_family = AF_INET6; |
48 | addr6->sin6_addr = in6addr_any; |
49 | addr6->sin6_port = htons(PORT); |
50 | break; |
51 | default: |
52 | error(1, 0, "Unsupported family %d" , family); |
53 | } |
54 | |
55 | for (i = 0; i < count; ++i) { |
56 | rcv_fds[i] = socket(family, proto, 0); |
57 | if (rcv_fds[i] < 0) |
58 | error(1, errno, "failed to create receive socket" ); |
59 | |
60 | opt = 1; |
61 | if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt, |
62 | sizeof(opt))) |
63 | error(1, errno, "failed to set SO_REUSEPORT" ); |
64 | |
65 | if (bind(rcv_fds[i], (struct sockaddr *)&addr, sizeof(addr))) |
66 | error(1, errno, "failed to bind receive socket" ); |
67 | |
68 | if (proto == SOCK_STREAM && listen(rcv_fds[i], 10)) |
69 | error(1, errno, "failed to listen on receive port" ); |
70 | } |
71 | } |
72 | |
73 | static void send_from_v4(int proto) |
74 | { |
75 | struct sockaddr_in saddr, daddr; |
76 | int fd; |
77 | |
78 | saddr.sin_family = AF_INET; |
79 | saddr.sin_addr.s_addr = htonl(INADDR_ANY); |
80 | saddr.sin_port = 0; |
81 | |
82 | daddr.sin_family = AF_INET; |
83 | daddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); |
84 | daddr.sin_port = htons(PORT); |
85 | |
86 | fd = socket(AF_INET, proto, 0); |
87 | if (fd < 0) |
88 | error(1, errno, "failed to create send socket" ); |
89 | |
90 | if (bind(fd, (struct sockaddr *)&saddr, sizeof(saddr))) |
91 | error(1, errno, "failed to bind send socket" ); |
92 | |
93 | if (connect(fd, (struct sockaddr *)&daddr, sizeof(daddr))) |
94 | error(1, errno, "failed to connect send socket" ); |
95 | |
96 | if (send(fd, "a" , 1, 0) < 0) |
97 | error(1, errno, "failed to send message" ); |
98 | |
99 | close(fd); |
100 | } |
101 | |
102 | static int receive_once(int epfd, int proto) |
103 | { |
104 | struct epoll_event ev; |
105 | int i, fd; |
106 | char buf[8]; |
107 | |
108 | i = epoll_wait(epfd, &ev, 1, -1); |
109 | if (i < 0) |
110 | error(1, errno, "epoll_wait failed" ); |
111 | |
112 | if (proto == SOCK_STREAM) { |
113 | fd = accept(ev.data.fd, NULL, NULL); |
114 | if (fd < 0) |
115 | error(1, errno, "failed to accept" ); |
116 | i = recv(fd, buf, sizeof(buf), 0); |
117 | close(fd); |
118 | } else { |
119 | i = recv(ev.data.fd, buf, sizeof(buf), 0); |
120 | } |
121 | |
122 | if (i < 0) |
123 | error(1, errno, "failed to recv" ); |
124 | |
125 | return ev.data.fd; |
126 | } |
127 | |
128 | static void test(int *rcv_fds, int count, int proto) |
129 | { |
130 | struct epoll_event ev; |
131 | int epfd, i, test_fd; |
132 | int test_family; |
133 | socklen_t len; |
134 | |
135 | epfd = epoll_create(1); |
136 | if (epfd < 0) |
137 | error(1, errno, "failed to create epoll" ); |
138 | |
139 | ev.events = EPOLLIN; |
140 | for (i = 0; i < count; ++i) { |
141 | ev.data.fd = rcv_fds[i]; |
142 | if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev)) |
143 | error(1, errno, "failed to register sock epoll" ); |
144 | } |
145 | |
146 | send_from_v4(proto); |
147 | |
148 | test_fd = receive_once(epfd, proto); |
149 | len = sizeof(test_family); |
150 | if (getsockopt(test_fd, SOL_SOCKET, SO_DOMAIN, &test_family, &len)) |
151 | error(1, errno, "failed to read socket domain" ); |
152 | if (test_family != AF_INET) |
153 | error(1, 0, "expected to receive on v4 socket but got v6 (%d)" , |
154 | test_family); |
155 | |
156 | close(epfd); |
157 | } |
158 | |
159 | int main(void) |
160 | { |
161 | int rcv_fds[32], i; |
162 | |
163 | fprintf(stderr, "---- UDP IPv4 created before IPv6 ----\n" ); |
164 | build_rcv_fd(AF_INET, proto: SOCK_DGRAM, rcv_fds, count: 5); |
165 | build_rcv_fd(AF_INET6, proto: SOCK_DGRAM, rcv_fds: &(rcv_fds[5]), count: 5); |
166 | test(rcv_fds, count: 10, proto: SOCK_DGRAM); |
167 | for (i = 0; i < 10; ++i) |
168 | close(rcv_fds[i]); |
169 | |
170 | fprintf(stderr, "---- UDP IPv6 created before IPv4 ----\n" ); |
171 | build_rcv_fd(AF_INET6, proto: SOCK_DGRAM, rcv_fds, count: 5); |
172 | build_rcv_fd(AF_INET, proto: SOCK_DGRAM, rcv_fds: &(rcv_fds[5]), count: 5); |
173 | test(rcv_fds, count: 10, proto: SOCK_DGRAM); |
174 | for (i = 0; i < 10; ++i) |
175 | close(rcv_fds[i]); |
176 | |
177 | /* NOTE: UDP socket lookups traverse a different code path when there |
178 | * are > 10 sockets in a group. |
179 | */ |
180 | fprintf(stderr, "---- UDP IPv4 created before IPv6 (large) ----\n" ); |
181 | build_rcv_fd(AF_INET, proto: SOCK_DGRAM, rcv_fds, count: 16); |
182 | build_rcv_fd(AF_INET6, proto: SOCK_DGRAM, rcv_fds: &(rcv_fds[16]), count: 16); |
183 | test(rcv_fds, count: 32, proto: SOCK_DGRAM); |
184 | for (i = 0; i < 32; ++i) |
185 | close(rcv_fds[i]); |
186 | |
187 | fprintf(stderr, "---- UDP IPv6 created before IPv4 (large) ----\n" ); |
188 | build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds, 16); |
189 | build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[16]), 16); |
190 | test(rcv_fds, 32, SOCK_DGRAM); |
191 | for (i = 0; i < 32; ++i) |
192 | close(rcv_fds[i]); |
193 | |
194 | fprintf(stderr, "---- TCP IPv4 created before IPv6 ----\n" ); |
195 | build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 5); |
196 | build_rcv_fd(AF_INET6, SOCK_STREAM, &(rcv_fds[5]), 5); |
197 | test(rcv_fds, 10, SOCK_STREAM); |
198 | for (i = 0; i < 10; ++i) |
199 | close(rcv_fds[i]); |
200 | |
201 | fprintf(stderr, "---- TCP IPv6 created before IPv4 ----\n" ); |
202 | build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds, 5); |
203 | build_rcv_fd(AF_INET, SOCK_STREAM, &(rcv_fds[5]), 5); |
204 | test(rcv_fds, 10, SOCK_STREAM); |
205 | for (i = 0; i < 10; ++i) |
206 | close(rcv_fds[i]); |
207 | |
208 | fprintf(stderr, "SUCCESS\n" ); |
209 | return 0; |
210 | } |
211 | |