1/*	$NetBSD: tap.c,v 1.4 2009/05/12 21:08:30 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 1.4 2009/05/12 21:08:30 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
43static void tap_exit(void);
44static bool tap_send(channel_t *, packet_t *);
45static bool tap_recv(packet_t *);
46static void tap_down(channel_t *);
47
48void
49tap_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
129static void
130tap_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
158static bool
159tap_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
180static bool
181tap_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
197static void
198tap_down(channel_t *chan)
199{
200
201	/* we never close the tap channel */
202}
203