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/*
* Copyright (C) 2014-2016 Firejail Authors
*
* This file is part of firejail project
*
* 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.
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "fnet.h"
#include <arpa/inet.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/route.h>
#include <linux/if_bridge.h>
// add a veth device to a bridge
void net_bridge_add_interface(const char *bridge, const char *dev) {
if (strlen(bridge) > IFNAMSIZ) {
fprintf(stderr, "Error fnet: invalid network device name %s\n", bridge);
exit(1);
}
// somehow adding the interface to the bridge resets MTU on bridge device!!!
// workaround: restore MTU on the bridge device
// todo: put a real fix in
int mtu1 = net_get_mtu(bridge);
struct ifreq ifr;
int err;
int ifindex = if_nametoindex(dev);
if (ifindex <= 0)
errExit("if_nametoindex");
int sock;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, bridge, IFNAMSIZ);
#ifdef SIOCBRADDIF
ifr.ifr_ifindex = ifindex;
err = ioctl(sock, SIOCBRADDIF, &ifr);
if (err < 0)
#endif
{
unsigned long args[4] = { BRCTL_ADD_IF, ifindex, 0, 0 };
ifr.ifr_data = (char *) args;
err = ioctl(sock, SIOCDEVPRIVATE, &ifr);
}
(void) err;
close(sock);
int mtu2 = net_get_mtu(bridge);
if (mtu1 != mtu2) {
net_set_mtu(bridge, mtu1);
}
}
// bring interface up
void net_if_up(const char *ifname) {
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error fnet: invalid network device name %s\n", ifname);
exit(1);
}
int sock = socket(AF_INET,SOCK_DGRAM,0);
if (sock < 0)
errExit("socket");
// get the existing interface flags
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
ifr.ifr_addr.sa_family = AF_INET;
// read the existing flags
if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0) {
close(sock);
printf("Error fnet: cannot bring up interface %s\n", ifname);
errExit("ioctl");
}
ifr.ifr_flags |= IFF_UP;
// set the new flags
if (ioctl( sock, SIOCSIFFLAGS, &ifr ) < 0) {
close(sock);
printf("Error fnet: cannot bring up interface %s\n", ifname);
errExit("ioctl");
}
// checking
// read the existing flags
if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0) {
close(sock);
printf("Error fnet: cannot bring up interface %s\n", ifname);
errExit("ioctl");
}
// wait not more than 500ms for the interface to come up
int cnt = 0;
while (cnt < 50) {
usleep(10000); // sleep 10ms
// read the existing flags
if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0) {
close(sock);
printf("Error fnet: cannot bring up interface %s\n", ifname);
errExit("ioctl");
}
if (ifr.ifr_flags & IFF_RUNNING)
break;
cnt++;
}
close(sock);
}
int net_get_mtu(const char *ifname) {
int mtu = 0;
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error fnet: invalid network device name %s\n", ifname);
exit(1);
}
int s;
struct ifreq ifr;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) == 0)
mtu = ifr.ifr_mtu;
close(s);
return mtu;
}
void net_set_mtu(const char *ifname, int mtu) {
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error fnet: invalid network device name %s\n", ifname);
exit(1);
}
int s;
struct ifreq ifr;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
ifr.ifr_mtu = mtu;
if (ioctl(s, SIOCSIFMTU, (caddr_t)&ifr) != 0)
fprintf(stderr, "Warning fnet: cannot set mtu for interface %s\n", ifname);
close(s);
}
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