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
tap_init(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
tap_exit(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
tap_send(channel_t * chan,packet_t * pkt)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
tap_recv(packet_t * pkt)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
tap_down(channel_t * chan)198 tap_down(channel_t *chan)
199 {
200
201 /* we never close the tap channel */
202 }
203