1 /* tunctl.c - Control tap/tun network devices. 2 * 3 * Copyright 2016 Rob Landley <rob (at) landley.net> 4 * 5 * See http://kernel.org/doc/Documentation/networking/tuntap.txt 6 * 7 * This is useful for things like "kvm -netdev tap" and containers. 8 * See https://landley.net/lxc/02-networking.html for example usage. 9 * 10 * todo: bridge mode 11 * -b bridge daemon (forwards packets between NAME and NAME2 interfaces) 12 13 14 USE_TUNCTL(NEWTOY(tunctl, "<1>1t|d|u:T[!td]", TOYFLAG_USR|TOYFLAG_BIN)) 15 16 config TUNCTL 17 bool "tunctl" 18 default y 19 help 20 usage: tunctl [-dtT] [-u USER] NAME 21 22 Create and delete tun/tap virtual ethernet devices. 23 24 -T Use tap (ethernet frames) instead of tun (ip packets) 25 -d Delete tun/tap device 26 -t Create tun/tap device 27 -u Set owner (user who can read/write device without root access) 28 */ 29 30 #define FOR_tunctl 31 #include "toys.h" 32 #include <linux/if_tun.h> 33 34 GLOBALS( 35 char *user; 36 ) 37 38 void tunctl_main(void) 39 { 40 struct ifreq *ifr = (void *)toybuf; 41 uid_t u = TT.user ? xgetuid(TT.user) : 0; 42 int fd = xopen("/dev/net/tun", O_RDWR); 43 44 // Associate filehandle with device 45 ifr->ifr_flags = ((toys.optflags&FLAG_T) ? IFF_TUN : IFF_TAP)|IFF_NO_PI; 46 strncpy(ifr->ifr_name, *toys.optargs, sizeof(ifr->ifr_name)); 47 xioctl(fd, TUNSETIFF, toybuf); 48 49 if (toys.optflags&FLAG_t) { 50 xioctl(fd, TUNSETPERSIST, (void *)1); 51 xioctl(fd, TUNSETOWNER, (void *)(long)u); 52 } else xioctl(fd, TUNSETPERSIST, (void *)0); 53 } 54
