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/* tunctl.c - Control tap/tun network devices.
*
* Copyright 2016 Rob Landley <rob@landley.net>
*
* See http://kernel.org/doc/Documentation/networking/tuntap.txt
*
* This is useful for things like "kvm -netdev tap" and containers.
* See https://landley.net/lxc/02-networking.html for example usage.
*
* TODO: bridge mode
* -b bridge daemon (forwards packets between NAME and NAME2 interfaces)
USE_TUNCTL(NEWTOY(tunctl, "<1>1t|d|u:T[!td]", TOYFLAG_USR|TOYFLAG_BIN))
config TUNCTL
bool "tunctl"
default y
help
usage: tunctl [-dtT] [-u USER] NAME
Create and delete tun/tap virtual ethernet devices.
-T Use tap (ethernet frames) instead of tun (ip packets)
-d Delete tun/tap device
-t Create tun/tap device
-u Set owner (user who can read/write device without root access)
*/
#define FOR_tunctl
#include "toys.h"
#include <linux/if_tun.h>
GLOBALS(
char *u;
)
void tunctl_main(void)
{
struct ifreq *ifr = (void *)toybuf;
uid_t u = TT.u ? xgetuid(TT.u) : 0;
int fd = xopen("/dev/net/tun", O_RDWR);
// Associate filehandle with device
ifr->ifr_flags = ((toys.optflags&FLAG_T) ? IFF_TUN : IFF_TAP)|IFF_NO_PI;
strncpy(ifr->ifr_name, *toys.optargs, sizeof(ifr->ifr_name));
xioctl(fd, TUNSETIFF, toybuf);
if (toys.optflags&FLAG_t) {
xioctl(fd, TUNSETPERSIST, (void *)1);
xioctl(fd, TUNSETOWNER, (void *)(long)u);
} else xioctl(fd, TUNSETPERSIST, (void *)0);
}
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