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| | // SPDX-License-Identifier: GPL-2.0-or-later
/* PASST - Plug A Simple Socket Transport
* for qemu/UNIX domain socket mode
*
* PASTA - Pack A Subtle Tap Abstraction
* for network namespace/tap device mode
*
* doc/migration/target.c - Mock of TCP migration target, use with passt-repair
*
* Copyright (c) 2025 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <unistd.h>
#include <netdb.h>
#include <netinet/tcp.h>
int main(int argc, char **argv)
{
struct sockaddr_in a = { AF_INET, htons(atoi(argv[3])), { 0 }, { 0 } };
struct addrinfo hints = { 0, AF_UNSPEC, SOCK_STREAM, 0, 0,
NULL, NULL, NULL };
struct sockaddr_un a_helper = { AF_UNIX, { 0 } };
int s, s_helper, seq;
int8_t cmd;
struct iovec iov = { &cmd, sizeof(cmd) };
char buf[CMSG_SPACE(sizeof(int))];
struct msghdr msg = { NULL, 0, &iov, 1, buf, sizeof(buf), 0 };
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
struct addrinfo *r;
(void)argc;
strcpy(a_helper.sun_path, argv[4]);
getaddrinfo(argv[1], argv[2], &hints, &r);
if (argc != 7) {
fprintf(stderr,
"%s DST_ADDR DST_PORT SRC_PORT HELPER_PATH SSEQ RSEQ\n",
argv[0]);
return -1;
}
/* Prepare socket, bind to source port */
s = socket(r->ai_family, SOCK_STREAM, IPPROTO_TCP);
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &((int){ 1 }), sizeof(int));
bind(s, (struct sockaddr *)&a, sizeof(a));
/* Wait for helper */
s_helper = socket(AF_UNIX, SOCK_STREAM, 0);
unlink(a_helper.sun_path);
bind(s_helper, (struct sockaddr *)&a_helper, sizeof(a_helper));
listen(s_helper, 1);
s_helper = accept(s_helper, NULL, NULL);
/* Set up message for helper, with socket */
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &s, sizeof(s));
/* Send command to helper: turn repair mode on, wait for reply */
cmd = TCP_REPAIR_ON;
sendmsg(s_helper, &msg, 0);
recv(s_helper, &((int){ 0 }), 1, 0);
/* Set sending sequence */
seq = TCP_SEND_QUEUE;
setsockopt(s, SOL_TCP, TCP_REPAIR_QUEUE, &seq, sizeof(seq));
seq = atoi(argv[5]);
setsockopt(s, SOL_TCP, TCP_QUEUE_SEQ, &seq, sizeof(seq));
/* Set receiving sequence */
seq = TCP_RECV_QUEUE;
setsockopt(s, SOL_TCP, TCP_REPAIR_QUEUE, &seq, sizeof(seq));
seq = atoi(argv[6]);
setsockopt(s, SOL_TCP, TCP_QUEUE_SEQ, &seq, sizeof(seq));
/* Connect setting kernel state only, without actual SYN / handshake */
connect(s, r->ai_addr, r->ai_addrlen);
/* Send command to helper: turn repair mode off, wait for reply */
cmd = TCP_REPAIR_OFF;
sendmsg(s_helper, &msg, 0);
recv(s_helper, &((int8_t){ 0 }), 1, 0);
/* Terminate helper */
close(s_helper);
/* Send some more data */
send(s, "after migration\n", sizeof("after migration\n"), 0);
}
|