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/* strongSwan IPsec interfaces management
* Copyright (C) 2001-2002 Mathieu Lafon - Arkoon Network Security
* 2009 Heiko Hund - Astaro AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* 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 <sys/socket.h>
#include <sys/ioctl.h>
#include <linux/rtnetlink.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <freeswan.h>
#include <constants.h>
#include <defs.h>
#include <log.h>
#include "interfaces.h"
#include "exec.h"
#include "files.h"
/*
* Get the default route information via rtnetlink
*/
void
get_defaultroute(defaultroute_t *defaultroute)
{
union {
struct {
struct nlmsghdr nh;
struct rtmsg rt;
} m;
char buf[4096];
} rtu;
struct nlmsghdr *nh;
uint32_t best_metric = ~0;
ssize_t msglen;
int fd;
bzero(&rtu, sizeof(rtu));
rtu.m.nh.nlmsg_len = NLMSG_LENGTH(sizeof(rtu.m.rt));
rtu.m.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
rtu.m.nh.nlmsg_type = RTM_GETROUTE;
rtu.m.rt.rtm_family = AF_INET;
rtu.m.rt.rtm_table = RT_TABLE_UNSPEC;
rtu.m.rt.rtm_protocol = RTPROT_UNSPEC;
rtu.m.rt.rtm_type = RTN_UNICAST;
fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
if (fd == -1)
{
plog("could not create rtnetlink socket");
return;
}
if (send(fd, &rtu, rtu.m.nh.nlmsg_len, 0) == -1)
{
plog("could not write to rtnetlink socket");
close(fd);
return;
}
msglen = recv(fd, &rtu, sizeof(rtu), MSG_WAITALL);
if (msglen == -1)
{
plog("could not read from rtnetlink socket");
close(fd);
return;
}
close(fd);
for (nh = &rtu.m.nh; NLMSG_OK(nh, msglen); nh = NLMSG_NEXT(nh, msglen))
{
struct rtmsg *rt;
struct rtattr *rta;
uint32_t rtalen, metric = 0;
struct in_addr gw = { .s_addr = INADDR_ANY };
int iface_idx = -1;
if (nh->nlmsg_type == NLMSG_ERROR)
{
plog("error from rtnetlink");
return;
}
if (nh->nlmsg_type == NLMSG_DONE)
break;
rt = NLMSG_DATA(nh);
if ( rt->rtm_dst_len != 0
|| (rt->rtm_table != RT_TABLE_MAIN
&& rt->rtm_table != RT_TABLE_DEFAULT) )
continue;
rta = RTM_RTA(rt);
rtalen = RTM_PAYLOAD(nh);
while ( RTA_OK(rta, rtalen) )
{
switch (rta->rta_type)
{
case RTA_GATEWAY:
gw = *(struct in_addr *) RTA_DATA(rta);
break;
case RTA_OIF:
iface_idx = *(int *) RTA_DATA(rta);
break;
case RTA_PRIORITY:
metric = *(uint32_t *) RTA_DATA(rta);
break;
}
rta = RTA_NEXT(rta, rtalen);
}
if (metric < best_metric
&& gw.s_addr != INADDR_ANY
&& iface_idx != -1)
{
struct ifreq req;
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
{
plog("could not open AF_INET socket");
defaultroute->defined = FALSE;
break;
}
bzero(&req, sizeof(req));
req.ifr_ifindex = iface_idx;
ioctl(fd, SIOCGIFNAME, &req);
ioctl(fd, SIOCGIFADDR, &req);
close(fd);
strncpy(defaultroute->iface, req.ifr_name, IFNAMSIZ);
defaultroute->addr.u.v4 = *((struct sockaddr_in *) &req.ifr_addr);
defaultroute->nexthop.u.v4.sin_family = AF_INET;
defaultroute->nexthop.u.v4.sin_addr = gw;
DBG(DBG_CONTROL,
char addr[20];
char nexthop[20];
addrtot(&defaultroute->addr, 0, addr, sizeof(addr));
addrtot(&defaultroute->nexthop, 0, nexthop, sizeof(nexthop));
DBG_log(
( !defaultroute->defined
? "Default route found: iface=%s, addr=%s, nexthop=%s"
: "Better default route: iface=%s, addr=%s, nexthop=%s"
), defaultroute->iface, addr, nexthop
)
);
best_metric = metric;
defaultroute->defined = TRUE;
}
}
if (!defaultroute->defined)
plog("no default route - cannot cope with %%defaultroute!!!");
}
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