tap.c revision 330449 
1/*	$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $	*/
2
3/*-
4 * SPDX-License-Identifier: BSD-2-Clause-NetBSD
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/* $FreeBSD: stable/11/usr.sbin/bluetooth/btpand/tap.c 330449 2018-03-05 07:26:05Z eadler $ */
31
32#include <sys/cdefs.h>
33__RCSID("$NetBSD: tap.c,v 1.1 2008/08/17 13:20:57 plunky Exp $");
34
35#include <sys/types.h>
36#include <sys/param.h>
37#include <sys/ioctl.h>
38#include <sys/uio.h>
39
40#include <net/if_tap.h>
41
42#include <fcntl.h>
43#include <libutil.h>
44#include <paths.h>
45#include <stdio.h>
46#include <unistd.h>
47
48#define L2CAP_SOCKET_CHECKED
49#include "btpand.h"
50
51static bool tap_send(channel_t *, packet_t *);
52static bool tap_recv(packet_t *);
53
54void
55tap_init(void)
56{
57	channel_t *chan;
58	struct ifreq ifr;
59	int fd, s;
60	char pidfile[PATH_MAX];
61
62	fd = open(interface_name, O_RDWR);
63	if (fd == -1) {
64		log_err("Could not open \"%s\": %m", interface_name);
65		exit(EXIT_FAILURE);
66	}
67
68	memset(&ifr, 0, sizeof(ifr));
69	if (ioctl(fd, TAPGIFNAME, &ifr) == -1) {
70		log_err("Could not get interface name: %m");
71		exit(EXIT_FAILURE);
72	}
73
74	s = socket(AF_INET, SOCK_DGRAM, 0);
75	if (s == -1) {
76		log_err("Could not open PF_LINK socket: %m");
77		exit(EXIT_FAILURE);
78	}
79
80	ifr.ifr_addr.sa_family = AF_LINK;
81	ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
82	b2eaddr(ifr.ifr_addr.sa_data, &local_bdaddr);
83
84	if (ioctl(s, SIOCSIFLLADDR, &ifr) == -1) {
85		log_err("Could not set %s physical address: %m", ifr.ifr_name);
86		exit(EXIT_FAILURE);
87	}
88
89	if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1) {
90		log_err("Could not get interface flags: %m");
91		exit(EXIT_FAILURE);
92	}
93
94	if ((ifr.ifr_flags & IFF_UP) == 0) {
95		ifr.ifr_flags |= IFF_UP;
96
97		if (ioctl(s, SIOCSIFFLAGS, &ifr) == -1) {
98			log_err("Could not set IFF_UP: %m");
99			exit(EXIT_FAILURE);
100		}
101	}
102
103	close(s);
104
105	log_info("Using interface %s with addr %s", ifr.ifr_name,
106		ether_ntoa((struct ether_addr *)&ifr.ifr_addr.sa_data));
107
108	chan = channel_alloc();
109	if (chan == NULL)
110		exit(EXIT_FAILURE);
111
112	chan->send = tap_send;
113	chan->recv = tap_recv;
114	chan->mru = ETHER_HDR_LEN + ETHER_MAX_LEN;
115	memcpy(chan->raddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
116	memcpy(chan->laddr, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
117	chan->state = CHANNEL_OPEN;
118	if (!channel_open(chan, fd))
119		exit(EXIT_FAILURE);
120
121	snprintf(pidfile, sizeof(pidfile), "%s/%s.pid",
122		_PATH_VARRUN, ifr.ifr_name);
123	chan->pfh = pidfile_open(pidfile, 0600, NULL);
124	if (chan->pfh == NULL)
125		log_err("can't create pidfile");
126	else if (pidfile_write(chan->pfh) < 0) {
127		log_err("can't write pidfile");
128		pidfile_remove(chan->pfh);
129		chan->pfh = NULL;
130	}
131}
132
133static bool
134tap_send(channel_t *chan, packet_t *pkt)
135{
136	struct iovec iov[4];
137	ssize_t nw;
138
139	iov[0].iov_base = pkt->dst;
140	iov[0].iov_len = ETHER_ADDR_LEN;
141	iov[1].iov_base = pkt->src;
142	iov[1].iov_len = ETHER_ADDR_LEN;
143	iov[2].iov_base = pkt->type;
144	iov[2].iov_len = ETHER_TYPE_LEN;
145	iov[3].iov_base = pkt->ptr;
146	iov[3].iov_len = pkt->len;
147
148	/* tap device write never fails */
149	nw = writev(chan->fd, iov, __arraycount(iov));
150	assert(nw > 0);
151
152	return true;
153}
154
155static bool
156tap_recv(packet_t *pkt)
157{
158
159	if (pkt->len < ETHER_HDR_LEN)
160		return false;
161
162	pkt->dst = pkt->ptr;
163	packet_adj(pkt, ETHER_ADDR_LEN);
164	pkt->src = pkt->ptr;
165	packet_adj(pkt, ETHER_ADDR_LEN);
166	pkt->type = pkt->ptr;
167	packet_adj(pkt, ETHER_TYPE_LEN);
168
169	return true;
170}
171