static int tap_alloc(char *dev, size_t dev_size) { int tap_fd, if_fd, ppa = -1; static int ip_fd = 0; char *ptr; static int arp_fd = 0; int ip_muxid, arp_muxid; struct strioctl strioc_if, strioc_ppa; int link_type = I_PLINK; struct lifreq ifr; char actual_name[32] = ""; memset(&ifr, 0x0, sizeof(ifr)); if( *dev ){ ptr = dev; while( *ptr && !qemu_isdigit((int)*ptr) ) ptr++; ppa = atoi(ptr); } /* Check if IP device was opened */ if( ip_fd ) close(ip_fd); TFR(ip_fd = open("/dev/udp", O_RDWR, 0)); if (ip_fd < 0) { syslog(LOG_ERR, "Can't open /dev/ip (actually /dev/udp)"); return -1; } TFR(tap_fd = open("/dev/tap", O_RDWR, 0)); if (tap_fd < 0) { syslog(LOG_ERR, "Can't open /dev/tap"); return -1; } /* Assign a new PPA and get its unit number. */ strioc_ppa.ic_cmd = TUNNEWPPA; strioc_ppa.ic_timout = 0; strioc_ppa.ic_len = sizeof(ppa); strioc_ppa.ic_dp = (char *)&ppa; if ((ppa = ioctl (tap_fd, I_STR, &strioc_ppa)) < 0) syslog (LOG_ERR, "Can't assign new interface"); TFR(if_fd = open("/dev/tap", O_RDWR, 0)); if (if_fd < 0) { syslog(LOG_ERR, "Can't open /dev/tap (2)"); return -1; } if(ioctl(if_fd, I_PUSH, "ip") < 0){ syslog(LOG_ERR, "Can't push IP module"); return -1; } if (ioctl(if_fd, SIOCGLIFFLAGS, &ifr) < 0) syslog(LOG_ERR, "Can't get flags\n"); snprintf (actual_name, 32, "tap%d", ppa); pstrcpy(ifr.lifr_name, sizeof(ifr.lifr_name), actual_name); ifr.lifr_ppa = ppa; /* Assign ppa according to the unit number returned by tun device */ if (ioctl (if_fd, SIOCSLIFNAME, &ifr) < 0) syslog (LOG_ERR, "Can't set PPA %d", ppa); if (ioctl(if_fd, SIOCGLIFFLAGS, &ifr) <0) syslog (LOG_ERR, "Can't get flags\n"); /* Push arp module to if_fd */ if (ioctl (if_fd, I_PUSH, "arp") < 0) syslog (LOG_ERR, "Can't push ARP module (2)"); /* Push arp module to ip_fd */ if (ioctl (ip_fd, I_POP, NULL) < 0) syslog (LOG_ERR, "I_POP failed\n"); if (ioctl (ip_fd, I_PUSH, "arp") < 0) syslog (LOG_ERR, "Can't push ARP module (3)\n"); /* Open arp_fd */ TFR(arp_fd = open ("/dev/tap", O_RDWR, 0)); if (arp_fd < 0) syslog (LOG_ERR, "Can't open %s\n", "/dev/tap"); /* Set ifname to arp */ strioc_if.ic_cmd = SIOCSLIFNAME; strioc_if.ic_timout = 0; strioc_if.ic_len = sizeof(ifr); strioc_if.ic_dp = (char *)&ifr; if (ioctl(arp_fd, I_STR, &strioc_if) < 0){ syslog (LOG_ERR, "Can't set ifname to arp\n"); } if((ip_muxid = ioctl(ip_fd, I_LINK, if_fd)) < 0){ syslog(LOG_ERR, "Can't link TAP device to IP"); return -1; } if ((arp_muxid = ioctl (ip_fd, link_type, arp_fd)) < 0) syslog (LOG_ERR, "Can't link TAP device to ARP"); close (if_fd); memset(&ifr, 0x0, sizeof(ifr)); pstrcpy(ifr.lifr_name, sizeof(ifr.lifr_name), actual_name); ifr.lifr_ip_muxid = ip_muxid; ifr.lifr_arp_muxid = arp_muxid; if (ioctl (ip_fd, SIOCSLIFMUXID, &ifr) < 0) { ioctl (ip_fd, I_PUNLINK , arp_muxid); ioctl (ip_fd, I_PUNLINK, ip_muxid); syslog (LOG_ERR, "Can't set multiplexor id"); } snprintf(dev, dev_size, "tap%d", ppa); return tap_fd; }