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| | // SPDX-License-Identifier: GPL-2.0-or-later
/* liste-vs-repair.c
*
* Do listening sockets have address conflicts with sockets under repair
* ====================================================================
*
* When we accept() an incoming connection the accept()ed socket will have the
* same local address as the listening socket. This can be a complication on
* migration. On the migration target we've already set up listening sockets
* according to the command line. However to restore connections that we're
* migrating in we need to bind the new sockets to the same address, which would
* be an address conflict on the face of it. This test program verifies that
* enabling repair mode before bind() correctly suppresses that conflict.
*
* Copyright Red Hat
* Author: David Gibson <david@gibson.dropbear.id.au>
*/
/* NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp) */
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <sched.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "common.h"
#define PORT 13256U
#define CPORT 13257U
/* 127.0.0.1:PORT */
static const struct sockaddr_in addr = SOCKADDR_INIT(INADDR_LOOPBACK, PORT);
/* 127.0.0.1:CPORT */
static const struct sockaddr_in caddr = SOCKADDR_INIT(INADDR_LOOPBACK, CPORT);
/* Put ourselves into a network sandbox */
static void net_sandbox(void)
{
/* NOLINTNEXTLINE(altera-struct-pack-align) */
const struct req_t {
struct nlmsghdr nlh;
struct ifinfomsg ifm;
} __attribute__((packed)) req = {
.nlh.nlmsg_type = RTM_NEWLINK,
.nlh.nlmsg_flags = NLM_F_REQUEST,
.nlh.nlmsg_len = sizeof(req),
.nlh.nlmsg_seq = 1,
.ifm.ifi_family = AF_UNSPEC,
.ifm.ifi_index = 1,
.ifm.ifi_flags = IFF_UP,
.ifm.ifi_change = IFF_UP,
};
int nl;
if (unshare(CLONE_NEWUSER | CLONE_NEWNET))
die("unshare(): %s\n", strerror(errno));
/* Bring up lo in the new netns */
nl = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
if (nl < 0)
die("Can't create netlink socket: %s\n", strerror(errno));
if (send(nl, &req, sizeof(req), 0) < 0)
die("Netlink send(): %s\n", strerror(errno));
close(nl);
}
static void check(void)
{
int s1, s2, op;
s1 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s1 < 0)
die("socket() 1: %s\n", strerror(errno));
if (bind(s1, (struct sockaddr *)&addr, sizeof(addr)))
die("bind() 1: %s\n", strerror(errno));
if (listen(s1, 0))
die("listen(): %s\n", strerror(errno));
s2 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (s2 < 0)
die("socket() 2: %s\n", strerror(errno));
op = TCP_REPAIR_ON;
if (setsockopt(s2, SOL_TCP, TCP_REPAIR, &op, sizeof(op)))
die("TCP_REPAIR: %s\n", strerror(errno));
if (bind(s2, (struct sockaddr *)&addr, sizeof(addr)))
die("bind() 2: %s\n", strerror(errno));
if (connect(s2, (struct sockaddr *)&caddr, sizeof(caddr)))
die("connect(): %s\n", strerror(errno));
op = TCP_REPAIR_OFF_NO_WP;
if (setsockopt(s2, SOL_TCP, TCP_REPAIR, &op, sizeof(op)))
die("TCP_REPAIR: %s\n", strerror(errno));
close(s1);
close(s2);
}
int main(int argc, char *argv[])
{
(void)argc;
(void)argv;
net_sandbox();
check();
printf("Repair mode appears to properly suppress conflicts with listening sockets\n");
exit(0);
}
|