pf.c revision 1.1 
1/*
2 * Copyright (c) 1993-95 Mats O Jansson.  All rights reserved.
3 * Copyright (c) 1990 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * This code is partly derived from rarpd.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by Mats O Jansson.
19 * 4. The name of the author may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#ifndef LINT
35static char rcsid[] = "$Id: pf.c,v 1.1 1997/03/16 22:23:37 cjs Exp $";
36#endif
37
38#include <stdio.h>
39#include <unistd.h>
40#include <sys/types.h>
41#include <sys/time.h>
42#include <sys/ioctl.h>
43#include <sys/file.h>
44#include <sys/socket.h>
45#include <sys/uio.h>
46#include <net/if.h>
47
48#include <net/bpf.h>
49#include <sys/errno.h>
50
51#include <netinet/in.h>
52#include <netinet/if_ether.h>
53
54#include <netdb.h>
55#include <ctype.h>
56#include <strings.h>
57
58#include <syslog.h>
59#include <varargs.h>
60
61#include "common/mopdef.h"
62
63/*
64 * Variables
65 */
66
67extern int errno;
68extern int promisc;
69
70/*
71 * Return information to device.c how to open device.
72 * In this case the driver can handle both Ethernet type II and
73 * IEEE 802.3 frames (SNAP) in a single pfOpen.
74 */
75
76int
77pfTrans(interface)
78	char *interface;
79{
80	return TRANS_ETHER+TRANS_8023+TRANS_AND;
81}
82
83/*
84 * Open and initialize packet filter.
85 */
86
87int
88pfInit(interface, mode, protocol, typ)
89	char *interface;
90	u_short protocol;
91	int typ, mode;
92{
93	int	fd;
94	int	n = 0;
95	char	device[sizeof "/dev/bpf000"];
96	struct ifreq ifr;
97	u_int	dlt;
98	int	immediate;
99
100	static struct bpf_insn insns[] = {
101		BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 12),
102		BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 4, 0),
103		BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 20),
104		BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0x4711, 0, 3),
105		BPF_STMT(BPF_LD | BPF_H | BPF_ABS, 14),
106		BPF_JUMP(BPF_JMP | BPF_JEQ | BPF_K, 0xaaaa, 0, 1),
107		BPF_STMT(BPF_RET | BPF_K, 1520),
108		BPF_STMT(BPF_RET | BPF_K, 0),
109	};
110	static struct bpf_program filter = {
111		sizeof insns / sizeof(insns[0]),
112		insns
113	};
114
115  	/* Go through all the minors and find one that isn't in use. */
116	do {
117		(void) sprintf(device, "/dev/bpf%d", n++);
118		fd = open(device, mode);
119	} while (fd < 0 && errno == EBUSY);
120
121	if (fd < 0) {
122      		syslog(LOG_ERR,"pfInit: open bpf %m");
123		return(-1);
124	}
125
126	/* Set immediate mode so packets are processed as they arrive. */
127	immediate = 1;
128	if (ioctl(fd, BIOCIMMEDIATE, &immediate) < 0) {
129      		syslog(LOG_ERR,"pfInit: BIOCIMMEDIATE: %m");
130		return(-1);
131	}
132	(void) strncpy(ifr.ifr_name, interface, sizeof ifr.ifr_name);
133	if (ioctl(fd, BIOCSETIF, (caddr_t) & ifr) < 0) {
134      		syslog(LOG_ERR,"pfInit: BIOCSETIF: %m");
135		return(-1);
136	}
137	/* Check that the data link layer is an Ethernet; this code won't work
138	 * with anything else. */
139	if (ioctl(fd, BIOCGDLT, (caddr_t) & dlt) < 0) {
140      		syslog(LOG_ERR,"pfInit: BIOCGDLT: %m");
141		return(-1);
142	}
143	if (dlt != DLT_EN10MB) {
144      		syslog(LOG_ERR,"pfInit: %s is not ethernet", device);
145		return(-1);
146	}
147	if (promisc) {
148		/* Set promiscuous mode. */
149		if (ioctl(fd, BIOCPROMISC, (caddr_t)0) < 0) {
150      			syslog(LOG_ERR,"pfInit: BIOCPROMISC: %m");
151			return(-1);
152		}
153	}
154	/* Set filter program. */
155	insns[1].k = protocol;
156	insns[3].k = protocol;
157
158	if (ioctl(fd, BIOCSETF, (caddr_t) & filter) < 0) {
159      		syslog(LOG_ERR,"pfInit: BIOCSETF: %m");
160		return(-1);
161	}
162	return(fd);
163}
164
165/*
166 * Add a Multicast address to the interface
167 */
168
169int
170pfAddMulti(s, interface, addr)
171	int s;
172	char *interface, *addr;
173{
174	struct ifreq ifr;
175	int	fd;
176
177	strcpy(ifr.ifr_name, interface);
178
179	ifr.ifr_addr.sa_family = AF_UNSPEC;
180	bcopy(addr, ifr.ifr_addr.sa_data, 6);
181
182	/*
183	 * open a socket, temporarily, to use for SIOC* ioctls
184	 *
185	 */
186	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
187		syslog(LOG_ERR, "pfAddMulti: socket: %m");
188		return(-1);
189	}
190	if (ioctl(fd, SIOCADDMULTI, (caddr_t)&ifr) < 0) {
191		syslog(LOG_ERR, "pfAddMulti: SIOCADDMULTI: %m");
192		close(fd);
193		return(-1);
194	}
195	close(fd);
196
197	return(0);
198}
199
200/*
201 * Delete a Multicast address from the interface
202 */
203
204int
205pfDelMulti(s, interface, addr)
206	int s;
207	char *interface, *addr;
208{
209	struct ifreq ifr;
210	int	fd;
211
212	strcpy(ifr.ifr_name, interface);
213
214	ifr.ifr_addr.sa_family = AF_UNSPEC;
215	bcopy(addr, ifr.ifr_addr.sa_data, 6);
216
217	/*
218	 * open a socket, temporarily, to use for SIOC* ioctls
219	 *
220	 */
221	if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
222		syslog(LOG_ERR, "pfDelMulti: socket: %m");
223		return(-1);
224	}
225	if (ioctl(fd, SIOCDELMULTI, (caddr_t)&ifr) < 0) {
226		syslog(LOG_ERR, "pfAddMulti: SIOCDELMULTI: %m");
227		close(fd);
228		return(-1);
229	}
230	close(fd);
231
232	return(0);
233}
234
235/*
236 * read a packet
237 */
238
239int
240pfRead(fd, buf, len)
241	int	fd, len;
242	u_char *buf;
243{
244	return(read(fd, buf, len));
245}
246
247/*
248 * write a packet
249 */
250
251int
252pfWrite(fd, buf, len, trans)
253	int fd, len, trans;
254	u_char *buf;
255{
256
257	struct iovec iov[2];
258
259	switch (trans) {
260	case TRANS_8023:
261		iov[0].iov_base = (caddr_t)buf;
262		iov[0].iov_len = 22;
263		iov[1].iov_base = (caddr_t)buf+22;
264		iov[1].iov_len = len-22;
265		break;
266	default:
267		iov[0].iov_base = (caddr_t)buf;
268		iov[0].iov_len = 14;
269		iov[1].iov_base = (caddr_t)buf+14;
270		iov[1].iov_len = len-14;
271		break;
272	}
273
274	if (writev(fd, iov, 2) == len)
275		return(len);
276
277	return(-1);
278}
279
280