// SPDX-License-Identifier: GPL-2.0
#include <arpa/inet.h>
#include <error.h>
#include <errno.h>
#include <unistd.h>
int main(void)
{
int fd1, fd2, one = 1;
struct sockaddr_in6 bind_addr = {
.sin6_family = AF_INET6,
.sin6_port = htons(20000),
.sin6_flowinfo = htonl(0),
.sin6_addr = {},
.sin6_scope_id = 0,
};
inet_pton(AF_INET6, "::", &bind_addr.sin6_addr);
fd1 = socket(AF_INET6, SOCK_STREAM, IPPROTO_IP);
if (fd1 < 0) {
error(1, errno, "socket fd1");
return -1;
}
if (setsockopt(fd1, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
error(1, errno, "setsockopt(SO_REUSEADDR) fd1");
goto out_err1;
}
if (bind(fd1, (struct sockaddr *)&bind_addr, sizeof(bind_addr))) {
error(1, errno, "bind fd1");
goto out_err1;
}
if (sendto(fd1, NULL, 0, MSG_FASTOPEN, (struct sockaddr *)&bind_addr,
sizeof(bind_addr))) {
error(1, errno, "sendto fd1");
goto out_err1;
}
fd2 = socket(AF_INET6, SOCK_STREAM, IPPROTO_IP);
if (fd2 < 0) {
error(1, errno, "socket fd2");
goto out_err1;
}
if (setsockopt(fd2, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
error(1, errno, "setsockopt(SO_REUSEADDR) fd2");
goto out_err2;
}
if (bind(fd2, (struct sockaddr *)&bind_addr, sizeof(bind_addr))) {
error(1, errno, "bind fd2");
goto out_err2;
}
if (sendto(fd2, NULL, 0, MSG_FASTOPEN, (struct sockaddr *)&bind_addr,
sizeof(bind_addr)) != -1) {
error(1, errno, "sendto fd2");
goto out_err2;
}
if (listen(fd2, 0)) {
error(1, errno, "listen");
goto out_err2;
}
close(fd2);
close(fd1);
return 0;
out_err2:
close(fd2);
out_err1:
close(fd1);
return -1;
}