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1// SPDX-License-Identifier: GPL-2.02/*3 * It is possible to use SO_REUSEPORT to open multiple sockets bound to4 * equivalent local addresses using AF_INET and AF_INET6 at the same time. If5 * the AF_INET6 socket has IPV6_V6ONLY set, it's clear which socket should6 * receive a given incoming packet. However, when it is not set, incoming v47 * packets should prefer the AF_INET socket(s). This behavior was defined with8 * the original SO_REUSEPORT implementation, but broke with9 * e32ea7e74727 ("soreuseport: fast reuseport UDP socket selection")10 * This test creates these mixed AF_INET/AF_INET6 sockets and asserts the11 * AF_INET preference for v4 packets.12 */13 14#define _GNU_SOURCE15 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 29static const int PORT = 8888;30 31static 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 73static 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 102static 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 128static 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 159int 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, SOCK_DGRAM, rcv_fds, 5);165 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[5]), 5);166 test(rcv_fds, 10, 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, SOCK_DGRAM, rcv_fds, 5);172 build_rcv_fd(AF_INET, SOCK_DGRAM, &(rcv_fds[5]), 5);173 test(rcv_fds, 10, 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 there178 * are > 10 sockets in a group.179 */180 fprintf(stderr, "---- UDP IPv4 created before IPv6 (large) ----\n");181 build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 16);182 build_rcv_fd(AF_INET6, SOCK_DGRAM, &(rcv_fds[16]), 16);183 test(rcv_fds, 32, 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