1 /* $NetBSD: tap.c,v 1.5 2009/05/12 21:21:23 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 1.5 2009/05/12 21:21:23 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 void tap_exit(void); 44 static bool tap_send(channel_t *, packet_t *); 45 static bool tap_recv(packet_t *); 46 static void tap_down(channel_t *); 47 48 void 49 tap_init(void) 50 { 51 channel_t *chan; 52 struct sockaddr_dl *sdl; 53 struct if_laddrreq iflr; 54 struct ifreq ifr; 55 int fd, s; 56 57 fd = open(interface_name, O_RDWR); 58 if (fd == -1) { 59 log_err("Could not open \"%s\": %m", interface_name); 60 exit(EXIT_FAILURE); 61 } 62 63 memset(&ifr, 0, sizeof(ifr)); 64 if (ioctl(fd, TAPGIFNAME, &ifr) == -1) { 65 log_err("Could not get interface name: %m"); 66 exit(EXIT_FAILURE); 67 } 68 interface_name = strndup(ifr.ifr_name, IFNAMSIZ); 69 atexit(tap_exit); 70 71 s = socket(PF_LINK, SOCK_DGRAM, 0); 72 if (s == -1) { 73 log_err("Could not open PF_LINK socket: %m"); 74 exit(EXIT_FAILURE); 75 } 76 77 memset(&iflr, 0, sizeof(iflr)); 78 memcpy(iflr.iflr_name, ifr.ifr_name, IFNAMSIZ); 79 iflr.flags = IFLR_ACTIVE; 80 81 sdl = satosdl(sstosa(&iflr.addr)); 82 sdl->sdl_family = AF_LINK; 83 sdl->sdl_len = sizeof(struct sockaddr_dl); 84 sdl->sdl_alen = ETHER_ADDR_LEN; 85 b2eaddr(LLADDR(sdl), &local_bdaddr); 86 87 if (ioctl(s, SIOCALIFADDR, &iflr) == -1) { 88 log_err("Could not add %s link address: %m", iflr.iflr_name); 89 exit(EXIT_FAILURE); 90 } 91 92 if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) { 93 log_err("Could not get interface flags: %m"); 94 exit(EXIT_FAILURE); 95 } 96 97 if ((ifr.ifr_flags & IFF_UP) == 0) { 98 ifr.ifr_flags |= IFF_UP; 99 100 if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) { 101 log_err("Could not set IFF_UP: %m"); 102 exit(EXIT_FAILURE); 103 } 104 } 105 106 close(s); 107 108 log_info("Using interface %s with addr %s", 109 ifr.ifr_name, ether_ntoa((struct ether_addr *)LLADDR(sdl))); 110 111 chan = channel_alloc(); 112 if (chan == NULL) 113 exit(EXIT_FAILURE); 114 115 chan->send = tap_send; 116 chan->recv = tap_recv; 117 chan->down = tap_down; 118 chan->mru = ETHER_HDR_LEN + ETHER_MAX_LEN; 119 memcpy(chan->raddr, LLADDR(sdl), ETHER_ADDR_LEN); 120 memcpy(chan->laddr, LLADDR(sdl), ETHER_ADDR_LEN); 121 chan->state = CHANNEL_OPEN; 122 if (!channel_open(chan, fd)) 123 exit(EXIT_FAILURE); 124 125 if (pidfile(ifr.ifr_name) == -1) 126 log_err("pidfile not made"); 127 } 128 129 static void 130 tap_exit(void) 131 { 132 struct ifreq ifr; 133 int s; 134 135 s = socket(PF_LINK, SOCK_DGRAM, 0); 136 if (s == -1) { 137 log_err("Could not open PF_LINK socket: %m"); 138 return; 139 } 140 141 strncpy(ifr.ifr_name, interface_name, IFNAMSIZ); 142 if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) { 143 log_err("Could not get interface flags: %m"); 144 return; 145 } 146 147 if ((ifr.ifr_flags & IFF_UP)) { 148 ifr.ifr_flags &= ~IFF_UP; 149 if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) { 150 log_err("Could not clear IFF_UP: %m"); 151 return; 152 } 153 } 154 155 close(s); 156 } 157 158 static bool 159 tap_send(channel_t *chan, packet_t *pkt) 160 { 161 struct iovec iov[4]; 162 ssize_t nw; 163 164 iov[0].iov_base = pkt->dst; 165 iov[0].iov_len = ETHER_ADDR_LEN; 166 iov[1].iov_base = pkt->src; 167 iov[1].iov_len = ETHER_ADDR_LEN; 168 iov[2].iov_base = pkt->type; 169 iov[2].iov_len = ETHER_TYPE_LEN; 170 iov[3].iov_base = pkt->ptr; 171 iov[3].iov_len = pkt->len; 172 173 /* tap device write never fails */ 174 nw = writev(chan->fd, iov, __arraycount(iov)); 175 assert(nw > 0); 176 177 return true; 178 } 179 180 static bool 181 tap_recv(packet_t *pkt) 182 { 183 184 if (pkt->len < ETHER_HDR_LEN) 185 return false; 186 187 pkt->dst = pkt->ptr; 188 packet_adj(pkt, ETHER_ADDR_LEN); 189 pkt->src = pkt->ptr; 190 packet_adj(pkt, ETHER_ADDR_LEN); 191 pkt->type = pkt->ptr; 192 packet_adj(pkt, ETHER_TYPE_LEN); 193 194 return true; 195 } 196 197 static void 198 tap_down(channel_t *chan) 199 { 200 201 /* we never close the tap channel */ 202 } 203
Indexes created Sat Sep 20 22:09:52 GMT 2025