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// SPDX-License-Identifier: GPL-2.0
/* Test that sockets listening on a specific address are preferred
* over sockets listening on addr_any.
*/
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <error.h>
#include <linux/in.h>
#include <linux/unistd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
static const char *IP4_ADDR = "127.0.0.1";
static const char *IP6_ADDR = "::1";
static const char *IP4_MAPPED6 = "::ffff:127.0.0.1";
static const int PORT = 8888;
static void build_rcv_fd(int family, int proto, int *rcv_fds, int count,
const char *addr_str)
{
struct sockaddr_in addr4 = {0};
struct sockaddr_in6 addr6 = {0};
struct sockaddr *addr;
int opt, i, sz;
memset(&addr, 0, sizeof(addr));
switch (family) {
case AF_INET:
addr4.sin_family = family;
if (!addr_str)
addr4.sin_addr.s_addr = htonl(INADDR_ANY);
else if (!inet_pton(family, addr_str, &addr4.sin_addr.s_addr))
error(1, errno, "inet_pton failed: %s", addr_str);
addr4.sin_port = htons(PORT);
sz = sizeof(addr4);
addr = (struct sockaddr *)&addr4;
break;
case AF_INET6:
addr6.sin6_family = AF_INET6;
if (!addr_str)
addr6.sin6_addr = in6addr_any;
else if (!inet_pton(family, addr_str, &addr6.sin6_addr))
error(1, errno, "inet_pton failed: %s", addr_str);
addr6.sin6_port = htons(PORT);
sz = sizeof(addr6);
addr = (struct sockaddr *)&addr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
}
for (i = 0; i < count; ++i) {
rcv_fds[i] = socket(family, proto, 0);
if (rcv_fds[i] < 0)
error(1, errno, "failed to create receive socket");
opt = 1;
if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
sizeof(opt)))
error(1, errno, "failed to set SO_REUSEPORT");
if (bind(rcv_fds[i], addr, sz))
error(1, errno, "failed to bind receive socket");
if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
error(1, errno, "failed to listen on receive port");
}
}
static int connect_and_send(int family, int proto)
{
struct sockaddr_in saddr4 = {0};
struct sockaddr_in daddr4 = {0};
struct sockaddr_in6 saddr6 = {0};
struct sockaddr_in6 daddr6 = {0};
struct sockaddr *saddr, *daddr;
int fd, sz;
switch (family) {
case AF_INET:
saddr4.sin_family = AF_INET;
saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
saddr4.sin_port = 0;
daddr4.sin_family = AF_INET;
if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
error(1, errno, "inet_pton failed: %s", IP4_ADDR);
daddr4.sin_port = htons(PORT);
sz = sizeof(saddr4);
saddr = (struct sockaddr *)&saddr4;
daddr = (struct sockaddr *)&daddr4;
break;
case AF_INET6:
saddr6.sin6_family = AF_INET6;
saddr6.sin6_addr = in6addr_any;
daddr6.sin6_family = AF_INET6;
if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
error(1, errno, "inet_pton failed: %s", IP6_ADDR);
daddr6.sin6_port = htons(PORT);
sz = sizeof(saddr6);
saddr = (struct sockaddr *)&saddr6;
daddr = (struct sockaddr *)&daddr6;
break;
default:
error(1, 0, "Unsupported family %d", family);
}
fd = socket(family, proto, 0);
if (fd < 0)
error(1, errno, "failed to create send socket");
if (bind(fd, saddr, sz))
error(1, errno, "failed to bind send socket");
if (connect(fd, daddr, sz))
error(1, errno, "failed to connect send socket");
if (send(fd, "a", 1, 0) < 0)
error(1, errno, "failed to send message");
return fd;
}
static int receive_once(int epfd, int proto)
{
struct epoll_event ev;
int i, fd;
char buf[8];
i = epoll_wait(epfd, &ev, 1, 3);
if (i < 0)
error(1, errno, "epoll_wait failed");
if (proto == SOCK_STREAM) {
fd = accept(ev.data.fd, NULL, NULL);
if (fd < 0)
error(1, errno, "failed to accept");
i = recv(fd, buf, sizeof(buf), 0);
close(fd);
} else {
i = recv(ev.data.fd, buf, sizeof(buf), 0);
}
if (i < 0)
error(1, errno, "failed to recv");
return ev.data.fd;
}
static void test(int *rcv_fds, int count, int family, int proto, int fd)
{
struct epoll_event ev;
int epfd, i, send_fd, recv_fd;
epfd = epoll_create(1);
if (epfd < 0)
error(1, errno, "failed to create epoll");
ev.events = EPOLLIN;
for (i = 0; i < count; ++i) {
ev.data.fd = rcv_fds[i];
if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
error(1, errno, "failed to register sock epoll");
}
send_fd = connect_and_send(family, proto);
recv_fd = receive_once(epfd, proto);
if (recv_fd != fd)
error(1, 0, "received on an unexpected socket");
close(send_fd);
close(epfd);
}
int main(void)
{
/* Below we test that a socket listening on a specific address
* is always selected in preference over a socket listening
* on addr_any. Bugs where this is not the case often result
* in sockets created first or last to get picked. So below
* we make sure that there are always addr_any sockets created
* before and after a specific socket is created.
*/
int rcv_fds[10], i;
fprintf(stderr, "---- UDP IPv4 ----\n");
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds + 4, 1, IP4_ADDR);
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET, SOCK_DGRAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "---- UDP IPv6 ----\n");
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 4, 1, IP6_ADDR);
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET6, SOCK_DGRAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "---- UDP IPv4 mapped to IPv6 ----\n");
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 4, 1, IP4_MAPPED6);
build_rcv_fd(AF_INET, SOCK_DGRAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_DGRAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET, SOCK_DGRAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "---- TCP IPv4 ----\n");
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds + 4, 1, IP4_ADDR);
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET, SOCK_STREAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "---- TCP IPv6 ----\n");
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 4, 1, IP6_ADDR);
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET6, SOCK_STREAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "---- TCP IPv4 mapped to IPv6 ----\n");
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 2, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 4, 1, IP4_MAPPED6);
build_rcv_fd(AF_INET, SOCK_STREAM, rcv_fds + 5, 2, NULL);
build_rcv_fd(AF_INET6, SOCK_STREAM, rcv_fds + 7, 2, NULL);
test(rcv_fds, 9, AF_INET, SOCK_STREAM, rcv_fds[4]);
for (i = 0; i < 9; ++i)
close(rcv_fds[i]);
fprintf(stderr, "SUCCESS\n");
return 0;
}
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