1 /* $NetBSD: tap.c,v 1.2 2009/03/10 22:12:17 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 #include <sys/cdefs.h> 29 __RCSID("$NetBSD: tap.c,v 1.2 2009/03/10 22:12:17 plunky Exp $"); 30 31 #include <sys/ioctl.h> 32 #include <sys/uio.h> 33 34 #include <net/if_dl.h> 35 #include <net/if_tap.h> 36 37 #include <fcntl.h> 38 #include <unistd.h> 39 #include <util.h> 40 41 #include "btpand.h" 42 43 static bool tap_send(channel_t *, packet_t *); 44 static bool tap_recv(packet_t *); 45 46 void 47 tap_init(void) 48 { 49 channel_t *chan; 50 struct sockaddr_dl *sdl; 51 struct if_laddrreq iflr; 52 struct ifreq ifr; 53 int fd, s; 54 55 fd = open(interface_name, O_RDWR); 56 if (fd == -1) { 57 log_err("Could not open \"%s\": %m", interface_name); 58 exit(EXIT_FAILURE); 59 } 60 61 memset(&ifr, 0, sizeof(ifr)); 62 if (ioctl(fd, TAPGIFNAME, &ifr) == -1) { 63 log_err("Could not get interface name: %m"); 64 exit(EXIT_FAILURE); 65 } 66 67 s = socket(PF_LINK, SOCK_DGRAM, 0); 68 if (s == -1) { 69 log_err("Could not open PF_LINK socket: %m"); 70 exit(EXIT_FAILURE); 71 } 72 73 memset(&iflr, 0, sizeof(iflr)); 74 memcpy(iflr.iflr_name, ifr.ifr_name, IFNAMSIZ); 75 iflr.flags = IFLR_ACTIVE; 76 77 sdl = satosdl(sstosa(&iflr.addr)); 78 sdl->sdl_family = AF_LINK; 79 sdl->sdl_len = sizeof(struct sockaddr_dl); 80 sdl->sdl_alen = ETHER_ADDR_LEN; 81 b2eaddr(LLADDR(sdl), &local_bdaddr); 82 83 if (ioctl(s, SIOCALIFADDR, &iflr) == -1) { 84 log_err("Could not add %s link address: %m", iflr.iflr_name); 85 exit(EXIT_FAILURE); 86 } 87 88 if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) { 89 log_err("Could not get interface flags: %m"); 90 exit(EXIT_FAILURE); 91 } 92 93 if ((ifr.ifr_flags & IFF_UP) == 0) { 94 ifr.ifr_flags |= IFF_UP; 95 96 if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) { 97 log_err("Could not set IFF_UP: %m"); 98 exit(EXIT_FAILURE); 99 } 100 } 101 102 close(s); 103 104 log_info("Using interface %s with addr %s", 105 ifr.ifr_name, ether_ntoa((struct ether_addr *)LLADDR(sdl))); 106 107 chan = channel_alloc(); 108 if (chan == NULL) 109 exit(EXIT_FAILURE); 110 111 chan->send = tap_send; 112 chan->recv = tap_recv; 113 chan->mru = ETHER_HDR_LEN + ETHER_MAX_LEN; 114 memcpy(chan->raddr, LLADDR(sdl), ETHER_ADDR_LEN); 115 memcpy(chan->laddr, LLADDR(sdl), ETHER_ADDR_LEN); 116 chan->state = CHANNEL_OPEN; 117 if (!channel_open(chan, fd)) 118 exit(EXIT_FAILURE); 119 120 if (pidfile(ifr.ifr_name) == -1) 121 log_err("pidfile not made"); 122 } 123 124 static bool 125 tap_send(channel_t *chan, packet_t *pkt) 126 { 127 struct iovec iov[4]; 128 ssize_t nw; 129 130 iov[0].iov_base = pkt->dst; 131 iov[0].iov_len = ETHER_ADDR_LEN; 132 iov[1].iov_base = pkt->src; 133 iov[1].iov_len = ETHER_ADDR_LEN; 134 iov[2].iov_base = pkt->type; 135 iov[2].iov_len = ETHER_TYPE_LEN; 136 iov[3].iov_base = pkt->ptr; 137 iov[3].iov_len = pkt->len; 138 139 /* tap device write never fails */ 140 nw = writev(chan->fd, iov, __arraycount(iov)); 141 _DIAGASSERT(nw > 0); 142 143 return true; 144 } 145 146 static bool 147 tap_recv(packet_t *pkt) 148 { 149 150 if (pkt->len < ETHER_HDR_LEN) 151 return false; 152 153 pkt->dst = pkt->ptr; 154 packet_adj(pkt, ETHER_ADDR_LEN); 155 pkt->src = pkt->ptr; 156 packet_adj(pkt, ETHER_ADDR_LEN); 157 pkt->type = pkt->ptr; 158 packet_adj(pkt, ETHER_TYPE_LEN); 159 160 return true; 161 } 162