1/*	$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * Copyright (c) 2008 Iain Hibbert
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30
31#include <sys/cdefs.h>
32__RCSID("$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $");
33
34#include <sys/types.h>
35#include <sys/param.h>
36#include <sys/ioctl.h>
37#include <sys/uio.h>
38
39#include <net/if_tap.h>
40
41#include <fcntl.h>
42#include <libutil.h>
43#include <paths.h>
44#include <stdio.h>
45#include <unistd.h>
46
47#define L2CAP_SOCKET_CHECKED
48#include "btpand.h"
49
50static bool tap_send(channel_t *, packet_t *);
51static bool tap_recv(packet_t *);
52
53void
54tap_init(void)
55{
56	channel_t *chan;
57	struct ifreq ifr;
58	int fd, s;
59	char pidfile[PATH_MAX];
60
61	fd = open(interface_name, O_RDWR);
62	if (fd == -1) {
63		log_err("Could not open \"%s\": %m", interface_name);
64		exit(EXIT_FAILURE);
65	}
66
67	memset(&ifr, 0, sizeof(ifr));
68	if (ioctl(fd, TAPGIFNAME, &ifr) == -1) {
69		log_err("Could not get interface name: %m");
70		exit(EXIT_FAILURE);
71	}
72
73	s = socket(AF_INET, SOCK_DGRAM, 0);
74	if (s == -1) {
75		log_err("Could not open PF_LINK socket: %m");
76		exit(EXIT_FAILURE);
77	}
78
79	ifr.ifr_addr.sa_family = AF_LINK;
80	ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
81	b2eaddr(ifr.ifr_addr.sa_data, &local_bdaddr);
82
83	if (ioctl(s, SIOCSIFLLADDR, &ifr) == -1) {
84		log_err("Could not set %s physical address: %m", ifr.ifr_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", ifr.ifr_name,
105		ether_ntoa((struct ether_addr *)&ifr.ifr_addr.sa_data));
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, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
115	memcpy(chan->laddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
116	chan->state = CHANNEL_OPEN;
117	if (!channel_open(chan, fd))
118		exit(EXIT_FAILURE);
119
120	snprintf(pidfile, sizeof(pidfile), "%s/%s.pid",
121		_PATH_VARRUN, ifr.ifr_name);
122	chan->pfh = pidfile_open(pidfile, 0600, NULL);
123	if (chan->pfh == NULL)
124		log_err("can't create pidfile");
125	else if (pidfile_write(chan->pfh) < 0) {
126		log_err("can't write pidfile");
127		pidfile_remove(chan->pfh);
128		chan->pfh = NULL;
129	}
130}
131
132static bool
133tap_send(channel_t *chan, packet_t *pkt)
134{
135	struct iovec iov[4];
136	ssize_t nw;
137
138	iov[0].iov_base = pkt->dst;
139	iov[0].iov_len = ETHER_ADDR_LEN;
140	iov[1].iov_base = pkt->src;
141	iov[1].iov_len = ETHER_ADDR_LEN;
142	iov[2].iov_base = pkt->type;
143	iov[2].iov_len = ETHER_TYPE_LEN;
144	iov[3].iov_base = pkt->ptr;
145	iov[3].iov_len = pkt->len;
146
147	/* tap device write never fails */
148	nw = writev(chan->fd, iov, __arraycount(iov));
149	assert(nw > 0);
150
151	return true;
152}
153
154static bool
155tap_recv(packet_t *pkt)
156{
157
158	if (pkt->len < ETHER_HDR_LEN)
159		return false;
160
161	pkt->dst = pkt->ptr;
162	packet_adj(pkt, ETHER_ADDR_LEN);
163	pkt->src = pkt->ptr;
164	packet_adj(pkt, ETHER_ADDR_LEN);
165	pkt->type = pkt->ptr;
166	packet_adj(pkt, ETHER_TYPE_LEN);
167
168	return true;
169}
170