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/**
* Copyright (C) 2012 Steven Barth <steven@midlink.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License v2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <time.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <stdbool.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include "odhcp6c.h"
static int sock = -1;
static unsigned seq = 0;
// Init rtnetlink socket
int init_rtnetlink(void)
{
sock = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
struct sockaddr_nl rtnl_kernel = { .nl_family = AF_NETLINK };
if (connect(sock, (struct sockaddr*)&rtnl_kernel, sizeof(rtnl_kernel)))
return -1;
return 0;
}
// CRUD addresses to interface
int set_rtnetlink_addr(int ifindex, const struct in6_addr *addr,
time_t pref, time_t valid)
{
int flags = NLM_F_REQUEST | NLM_F_ACK;
int cmd = RTM_DELADDR;
if (valid > 0) {
flags |= NLM_F_CREATE | NLM_F_REPLACE;
cmd = RTM_NEWADDR;
}
struct {
struct nlmsghdr nhm;
struct ifaddrmsg ifa;
struct rtattr rta_addr;
struct in6_addr addr;
struct rtattr rta_local;
struct in6_addr local;
struct rtattr rta_info;
struct ifa_cacheinfo info;
} req = {
{sizeof(req), cmd, flags, ++seq, 0},
{AF_INET6, 128, 0, RT_SCOPE_UNIVERSE, ifindex},
{sizeof(req.rta_addr) + sizeof(req.addr), IFA_ADDRESS},
*addr,
{sizeof(req.rta_local) + sizeof(req.local), IFA_LOCAL},
*addr,
{sizeof(req.rta_info) + sizeof(req.info), IFA_CACHEINFO},
{pref, valid, 0, 0}
};
send(sock, &req, sizeof(req), 0);
struct {
struct nlmsghdr nhm;
struct nlmsgerr err;
} reply;
recv(sock, &reply, sizeof(reply), 0);
char buf[INET6_ADDRSTRLEN];
inet_ntop(AF_INET6, addr, buf, sizeof(buf));
syslog(LOG_WARNING, "%s address %s/128 for iface %i: %s",
(valid) ? "assigning" : "removing", buf,
ifindex, strerror(-reply.err.error));
if (reply.err.error < 0 || valid == 0)
return reply.err.error;
// Check for duplicate addresses
struct timespec ts = {1, 0};
nanosleep(&ts, NULL);
req.nhm.nlmsg_type = RTM_GETADDR;
req.nhm.nlmsg_seq = ++seq;
req.nhm.nlmsg_flags = NLM_F_REQUEST;
send(sock, &req, sizeof(req), 0);
struct {
struct nlmsghdr nhm;
struct ifaddrmsg ifa;
uint8_t buf[1024];
} dad_reply;
recv(sock, &dad_reply, sizeof(dad_reply), 0);
if (dad_reply.nhm.nlmsg_type != RTM_NEWADDR ||
(dad_reply.ifa.ifa_flags & IFA_F_DADFAILED)) {
syslog(LOG_WARNING, "Removing duplicate address %s", buf);
set_rtnetlink_addr(ifindex, addr, 0, 0);
return -EADDRNOTAVAIL;
}
return 0;
}
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