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// SPDX-License-Identifier: GPL-2.0-or-later
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/types.h>
#include <sys/socket.h>
int main(int argc, const char **argv)
{
char cbuf[CMSG_SPACE(sizeof(__u32))];
struct addrinfo hints, *ai;
struct cmsghdr *cmsg;
struct iovec iov[1];
struct msghdr msg;
int mark;
int err;
int fd;
if (argc != 4) {
fprintf(stderr, "Usage: %s <dst_ip> <port> <mark>\n", argv[0]);
return 1;
}
mark = atoi(argv[3]);
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
ai = NULL;
err = getaddrinfo(argv[1], argv[2], &hints, &ai);
if (err) {
fprintf(stderr, "Can't resolve address: %s\n", strerror(errno));
return 1;
}
fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
if (fd < 0) {
fprintf(stderr, "Can't open socket: %s\n", strerror(errno));
freeaddrinfo(ai);
return 1;
}
iov[0].iov_base = "bla";
iov[0].iov_len = 4;
msg.msg_name = ai->ai_addr;
msg.msg_namelen = ai->ai_addrlen;
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = cbuf;
msg.msg_controllen = sizeof(cbuf);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SO_MARK;
cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
*(__u32 *)CMSG_DATA(cmsg) = mark;
err = sendmsg(fd, &msg, 0);
close(fd);
freeaddrinfo(ai);
return err != 4;
}
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