aboutsummaryrefslogtreecommitdiff
path: root/contrib/isc-dhcp/common/lpf.c
blob: d31d6f3cb96ecc7138d0ea921c960210b321699d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/* lpf.c

   Linux packet filter code, contributed by Brian Murrel at Interlinx
   Support Services in Vancouver, B.C. */

/*
 * Copyright (c) 1995, 1996, 1998, 1999
 * The Internet Software Consortium.    All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of The Internet Software Consortium nor the names
 *    of its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * This software has been written for the Internet Software Consortium
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
 * Enterprises.  To learn more about the Internet Software Consortium,
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
 * Enterprises, see ``http://www.vix.com''.
 */

#ifndef lint
static char copyright[] =
"$Id: lpf.c,v 1.1.2.6 1999/02/23 22:09:55 mellon Exp $ Copyright (c) 1995, 1996, 1998, 1999 The Internet Software Consortium.  All rights reserved.\n";
#endif /* not lint */

#include "dhcpd.h"
#if defined (USE_LPF_SEND) || defined (USE_LPF_RECEIVE)
#include <sys/ioctl.h>
#include <sys/uio.h>

#include <asm/types.h>
#include <linux/filter.h>
#include <linux/if_ether.h>
#include <netinet/in_systm.h>
#include "includes/netinet/ip.h"
#include "includes/netinet/udp.h"
#include "includes/netinet/if_ether.h"

/* Reinitializes the specified interface after an address change.   This
   is not required for packet-filter APIs. */

#ifdef USE_LPF_SEND
void if_reinitialize_send (info)
	struct interface_info *info;
{
}
#endif

#ifdef USE_LPF_RECEIVE
void if_reinitialize_receive (info)
	struct interface_info *info;
{
}
#endif

/* Called by get_interface_list for each interface that's discovered.
   Opens a packet filter for each interface and adds it to the select
   mask. */

int if_register_lpf (info)
	struct interface_info *info;
{
	int sock;
	char filename[50];
	int b;
	struct sockaddr sa;

	/* Make an LPF socket. */
	if ((sock = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ALL))) < 0) {
		if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
		    errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
		    errno == EAFNOSUPPORT)
			error ("socket: %m - make sure %s %s!",
			       "CONFIG_PACKET and CONFIG_FILTER are defined",
			       "in your kernel configuration");
		error("Open a socket for LPF: %m");
	}

	/* Bind to the interface name */
	memset (&sa, 0, sizeof sa);
	sa.sa_family = AF_PACKET;
	strncpy (sa.sa_data, (const char *)info -> ifp, sizeof sa.sa_data);
	if (bind (sock, &sa, sizeof sa)) {
		if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
		    errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
		    errno == EAFNOSUPPORT)
			error ("socket: %m - make sure %s %s!",
			       "CONFIG_PACKET and CONFIG_FILTER are defined",
			       "in your kernel configuration");
		error("Bind socket to interface: %m");
	}

	return sock;
}
#endif /* USE_LPF_SEND || USE_LPF_RECEIVE */

#ifdef USE_LPF_SEND
void if_register_send (info)
	struct interface_info *info;
{
	/* If we're using the lpf API for sending and receiving,
	   we don't need to register this interface twice. */
#ifndef USE_LPF_RECEIVE
	info -> wfdesc = if_register_lpf (info, interface);
#else
	info -> wfdesc = info -> rfdesc;
#endif
	if (!quiet_interface_discovery)
		note ("Sending on   LPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.htype,
				     info -> hw_address.hlen,
				     info -> hw_address.haddr),
		      (info -> shared_network ? "/" : ""),
		      (info -> shared_network ?
		       info -> shared_network -> name : ""));
}
#endif /* USE_LPF_SEND */

#ifdef USE_LPF_RECEIVE
/* Defined in bpf.c.   We can't extern these in dhcpd.h without pulling
   in bpf includes... */
extern struct sock_filter dhcp_bpf_filter [];
extern int dhcp_bpf_filter_len;

void if_register_receive (info)
	struct interface_info *info;
{
	struct sock_fprog p;

	/* Open a LPF device and hang it on this interface... */
	info -> rfdesc = if_register_lpf (info);

	/* Set up the bpf filter program structure.    This is defined in
	   bpf.c */
	p.len = dhcp_bpf_filter_len;
	p.filter = dhcp_bpf_filter;

        /* Patch the server port into the LPF  program...
	   XXX changes to filter program may require changes
	   to the insn number(s) used below! XXX */
	dhcp_bpf_filter [8].k = ntohs (local_port);

	if (setsockopt (info -> rfdesc, SOL_SOCKET, SO_ATTACH_FILTER, &p,
			sizeof p) < 0) {
		if (errno == ENOPROTOOPT || errno == EPROTONOSUPPORT ||
		    errno == ESOCKTNOSUPPORT || errno == EPFNOSUPPORT ||
		    errno == EAFNOSUPPORT)
			error ("socket: %m - make sure %s %s!",
			       "CONFIG_PACKET and CONFIG_FILTER are defined",
			       "in your kernel configuration");
		error ("Can't install packet filter program: %m");
	}
	if (!quiet_interface_discovery)
		note ("Listening on LPF/%s/%s%s%s",
		      info -> name,
		      print_hw_addr (info -> hw_address.htype,
				     info -> hw_address.hlen,
				     info -> hw_address.haddr),
		      (info -> shared_network ? "/" : ""),
		      (info -> shared_network ?
		       info -> shared_network -> name : ""));
}
#endif /* USE_LPF_RECEIVE */

#ifdef USE_LPF_SEND
ssize_t send_packet (interface, packet, raw, len, from, to, hto)
	struct interface_info *interface;
	struct packet *packet;
	struct dhcp_packet *raw;
	size_t len;
	struct in_addr from;
	struct sockaddr_in *to;
	struct hardware *hto;
{
	int bufp = 0;
	unsigned char buf [1500];
	struct sockaddr sa;
	int result;

	if (!strcmp (interface -> name, "fallback"))
		return send_fallback (interface, packet, raw,
				      len, from, to, hto);

	/* Assemble the headers... */
	assemble_hw_header (interface, buf, &bufp, hto);
	assemble_udp_ip_header (interface, buf, &bufp, from.s_addr,
				to -> sin_addr.s_addr, to -> sin_port,
				(unsigned char *)raw, len);
	memcpy (buf + bufp, raw, len);

	/* For some reason, SOCK_PACKET sockets can't be connected,
	   so we have to do a sentdo every time. */
	memset (&sa, 0, sizeof sa);
	sa.sa_family = AF_PACKET;
	strncpy (sa.sa_data,
		 (const char *)interface -> ifp, sizeof sa.sa_data);

	result = sendto (interface -> wfdesc, buf, bufp + len, 0,
			 &sa, sizeof sa);
	if (result < 0)
		warn ("send_packet: %m");
	return result;
}
#endif /* USE_LPF_SEND */

#ifdef USE_LPF_RECEIVE
ssize_t receive_packet (interface, buf, len, from, hfrom)
	struct interface_info *interface;
	unsigned char *buf;
	size_t len;
	struct sockaddr_in *from;
	struct hardware *hfrom;
{
	int nread;
	int length = 0;
	int offset = 0;
	unsigned char ibuf [1500];
	int bufix = 0;

	length = read (interface -> rfdesc, ibuf, sizeof ibuf);
	if (length <= 0)
		return length;

	bufix = 0;
	/* Decode the physical header... */
	offset = decode_hw_header (interface, ibuf, bufix, hfrom);

	/* If a physical layer checksum failed (dunno of any
	   physical layer that supports this, but WTH), skip this
	   packet. */
	if (offset < 0) {
		return 0;
	}

	bufix += offset;
	length -= offset;

	/* Decode the IP and UDP headers... */
	offset = decode_udp_ip_header (interface, ibuf, bufix,
				       from, (unsigned char *)0, length);

	/* If the IP or UDP checksum was bad, skip the packet... */
	if (offset < 0)
		return 0;

	bufix += offset;
	length -= offset;

	/* Copy out the data in the packet... */
	memcpy (buf, &ibuf [bufix], length);
	return length;
}

int can_unicast_without_arp ()
{
	return 1;
}

void maybe_setup_fallback ()
{
	struct interface_info *fbi;
	fbi = setup_fallback ();
	if (fbi) {
		if_register_fallback (fbi);
		add_protocol ("fallback", fallback_interface -> wfdesc,
			      fallback_discard, fallback_interface);
	}
}
#endif