1 /* $NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 Iain Hibbert 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 /* $FreeBSD$ */ 29 30 #include <sys/cdefs.h> 31 __RCSID("$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $"); 32 33 #include <sys/types.h> 34 #include <sys/param.h> 35 #include <sys/ioctl.h> 36 #include <sys/uio.h> 37 38 #include <net/if_tap.h> 39 40 #include <fcntl.h> 41 #include <libutil.h> 42 #include <paths.h> 43 #include <stdio.h> 44 #include <unistd.h> 45 46 #include "btpand.h" 47 48 static bool tap_send(channel_t *, packet_t *); 49 static bool tap_recv(packet_t *); 50 51 void 52 tap_init(void) 53 { 54 channel_t *chan; 55 struct ifreq ifr; 56 int fd, s; 57 char pidfile[PATH_MAX]; 58 59 fd = open(interface_name, O_RDWR); 60 if (fd == -1) { 61 log_err("Could not open \"%s\": %m", interface_name); 62 exit(EXIT_FAILURE); 63 } 64 65 memset(&ifr, 0, sizeof(ifr)); 66 if (ioctl(fd, TAPGIFNAME, &ifr) == -1) { 67 log_err("Could not get interface name: %m"); 68 exit(EXIT_FAILURE); 69 } 70 71 s = socket(AF_INET, SOCK_DGRAM, 0); 72 if (s == -1) { 73 log_err("Could not open PF_LINK socket: %m"); 74 exit(EXIT_FAILURE); 75 } 76 77 ifr.ifr_addr.sa_family = AF_LINK; 78 ifr.ifr_addr.sa_len = ETHER_ADDR_LEN; 79 b2eaddr(ifr.ifr_addr.sa_data, &local_bdaddr); 80 81 if (ioctl(s, SIOCSIFLLADDR, &ifr) == -1) { 82 log_err("Could not set %s physical address: %m", ifr.ifr_name); 83 exit(EXIT_FAILURE); 84 } 85 86 if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) { 87 log_err("Could not get interface flags: %m"); 88 exit(EXIT_FAILURE); 89 } 90 91 if ((ifr.ifr_flags & IFF_UP) == 0) { 92 ifr.ifr_flags |= IFF_UP; 93 94 if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) { 95 log_err("Could not set IFF_UP: %m"); 96 exit(EXIT_FAILURE); 97 } 98 } 99 100 close(s); 101 102 log_info("Using interface %s with addr %s", ifr.ifr_name, 103 ether_ntoa((struct ether_addr *)&ifr.ifr_addr.sa_data)); 104 105 chan = channel_alloc(); 106 if (chan == NULL) 107 exit(EXIT_FAILURE); 108 109 chan->send = tap_send; 110 chan->recv = tap_recv; 111 chan->mru = ETHER_HDR_LEN + ETHER_MAX_LEN; 112 memcpy(chan->raddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN); 113 memcpy(chan->laddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN); 114 chan->state = CHANNEL_OPEN; 115 if (!channel_open(chan, fd)) 116 exit(EXIT_FAILURE); 117 118 snprintf(pidfile, sizeof(pidfile), "%s/%s.pid", 119 _PATH_VARRUN, ifr.ifr_name); 120 chan->pfh = pidfile_open(pidfile, 0600, NULL); 121 if (chan->pfh == NULL) 122 log_err("can't create pidfile"); 123 else if (pidfile_write(chan->pfh) < 0) { 124 log_err("can't write pidfile"); 125 pidfile_remove(chan->pfh); 126 chan->pfh = NULL; 127 } 128 } 129 130 static bool 131 tap_send(channel_t *chan, packet_t *pkt) 132 { 133 struct iovec iov[4]; 134 ssize_t nw; 135 136 iov[0].iov_base = pkt->dst; 137 iov[0].iov_len = ETHER_ADDR_LEN; 138 iov[1].iov_base = pkt->src; 139 iov[1].iov_len = ETHER_ADDR_LEN; 140 iov[2].iov_base = pkt->type; 141 iov[2].iov_len = ETHER_TYPE_LEN; 142 iov[3].iov_base = pkt->ptr; 143 iov[3].iov_len = pkt->len; 144 145 /* tap device write never fails */ 146 nw = writev(chan->fd, iov, __arraycount(iov)); 147 assert(nw > 0); 148 149 return true; 150 } 151 152 static bool 153 tap_recv(packet_t *pkt) 154 { 155 156 if (pkt->len < ETHER_HDR_LEN) 157 return false; 158 159 pkt->dst = pkt->ptr; 160 packet_adj(pkt, ETHER_ADDR_LEN); 161 pkt->src = pkt->ptr; 162 packet_adj(pkt, ETHER_ADDR_LEN); 163 pkt->type = pkt->ptr; 164 packet_adj(pkt, ETHER_TYPE_LEN); 165 166 return true; 167 } 168