summaryrefslogtreecommitdiffstats
path: root/sys/netinet/ip_divert.c
blob: e4b82b94238482e4284773e2b1dee973b5558081 (plain)
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
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 *	$Id: ip_divert.c,v 1.37 1999/02/08 05:53:39 julian Exp $
 */

#include "opt_inet.h"
#include "opt_ipfw.h"
#include "opt_ipdivert.h"

#ifndef INET
#error "IPDIVERT requires INET."
#endif

#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/proc.h>

#include <vm/vm_zone.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>

/*
 * Divert sockets
 */

/*
 * Allocate enough space to hold a full IP packet
 */
#define	DIVSNDQ		(65536 + 100)
#define	DIVRCVQ		(65536 + 100)

/* Global variables */

/*
 * ip_input() and ip_output() set this secret value before calling us to
 * let us know which divert port to divert a packet to; this is done so
 * we can use the existing prototype for struct protosw's pr_input().
 * This is stored in host order.
 */
u_short ip_divert_port;

/*
 * A 16 bit cookie is passed to the user process.
 * The user process can send it back to help the caller know something
 * about where the packet came from.
 *
 * If IPFW is the caller then the cookie is the rule that sent
 * us here. On reinjection is is the rule after which processing
 * should continue. Leaving it the same will make processing start
 * at the rule number after that which sent it here. Setting it to
 * 0 will restart processing at the beginning. 
 */
u_int16_t ip_divert_cookie;

/* Internal variables */

static struct inpcbhead divcb;
static struct inpcbinfo divcbinfo;

static u_long	div_sendspace = DIVSNDQ;	/* XXX sysctl ? */
static u_long	div_recvspace = DIVRCVQ;	/* XXX sysctl ? */

/* Optimization: have this preinitialized */
static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };

/* Internal functions */

static int div_output(struct socket *so,
		struct mbuf *m, struct sockaddr *addr, struct mbuf *control);

/*
 * Initialize divert connection block queue.
 */
void
div_init(void)
{
	LIST_INIT(&divcb);
	divcbinfo.listhead = &divcb;
	/*
	 * XXX We don't use the hash list for divert IP, but it's easier
	 * to allocate a one entry hash list than it is to check all
	 * over the place for hashbase == NULL.
	 */
	divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
	divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
	divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb),
				   maxsockets, ZONE_INTERRUPT, 0);
}

/*
 * Setup generic address and protocol structures
 * for div_input routine, then pass them along with
 * mbuf chain. ip->ip_len is assumed to have had
 * the header length (hlen) subtracted out already.
 * We tell whether the packet was incoming or outgoing
 * by seeing if hlen == 0, which is a hack.
 */
void
div_input(struct mbuf *m, int hlen)
{
	struct ip *ip;
	struct inpcb *inp;
	struct socket *sa;

	/* Sanity check */
	if (ip_divert_port == 0)
		panic("div_input: port is 0");

	/* Assure header */
	if (m->m_len < sizeof(struct ip) &&
	    (m = m_pullup(m, sizeof(struct ip))) == 0) {
		return;
	}
	ip = mtod(m, struct ip *);

	/* Record divert cookie */
	divsrc.sin_port = ip_divert_cookie;
	ip_divert_cookie = 0;

	/* Restore packet header fields */
	ip->ip_len += hlen;
	HTONS(ip->ip_len);
	HTONS(ip->ip_off);

	/*
	 * Record receive interface address, if any
	 * But only for incoming packets.
	 */
	divsrc.sin_addr.s_addr = 0;
	if (hlen) {
		struct ifaddr *ifa;

#ifdef DIAGNOSTIC
		/* Sanity check */
		if (!(m->m_flags & M_PKTHDR))
			panic("div_input: no pkt hdr");
#endif

		/* More fields affected by ip_input() */
		HTONS(ip->ip_id);

		/* Find IP address for receive interface */
		for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first;
		    ifa != NULL; ifa = ifa->ifa_link.tqe_next) {
			if (ifa->ifa_addr == NULL)
				continue;
			if (ifa->ifa_addr->sa_family != AF_INET)
				continue;
			divsrc.sin_addr =
			    ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
			break;
		}
	}
	/*
	 * Record the incoming interface name whenever we have one.
	 */
	bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero));
	if (m->m_pkthdr.rcvif) {
		/*
		 * Hide the actual interface name in there in the 
		 * sin_zero array. XXX This needs to be moved to a
		 * different sockaddr type for divert, e.g.
		 * sockaddr_div with multiple fields like 
		 * sockaddr_dl. Presently we have only 7 bytes
		 * but that will do for now as most interfaces
		 * are 4 or less + 2 or less bytes for unit.
		 * There is probably a faster way of doing this,
		 * possibly taking it from the sockaddr_dl on the iface.
		 * This solves the problem of a P2P link and a LAN interface
		 * having the same address, which can result in the wrong
		 * interface being assigned to the packet when fed back
		 * into the divert socket. Theoretically if the daemon saves
		 * and re-uses the sockaddr_in as suggested in the man pages,
		 * this iface name will come along for the ride.
		 * (see div_output for the other half of this.)
		 */ 
		snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero),
			"%s%d", m->m_pkthdr.rcvif->if_name,
			m->m_pkthdr.rcvif->if_unit);
	}

	/* Put packet on socket queue, if any */
	sa = NULL;
	for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
		if (inp->inp_lport == htons(ip_divert_port))
			sa = inp->inp_socket;
	}
	ip_divert_port = 0;
	if (sa) {
		if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
				m, (struct mbuf *)0) == 0)
			m_freem(m);
		else
			sorwakeup(sa);
	} else {
		m_freem(m);
		ipstat.ips_noproto++;
		ipstat.ips_delivered--;
        }
}

/*
 * Deliver packet back into the IP processing machinery.
 *
 * If no address specified, or address is 0.0.0.0, send to ip_output();
 * otherwise, send to ip_input() and mark as having been received on
 * the interface with that address.
 */
static int
div_output(so, m, addr, control)
	struct socket *so;
	register struct mbuf *m;
	struct sockaddr *addr;
	struct mbuf *control;
{
	register struct inpcb *const inp = sotoinpcb(so);
	register struct ip *const ip = mtod(m, struct ip *);
	struct sockaddr_in *sin = (struct sockaddr_in *)addr;
	int error = 0;

	if (control)
		m_freem(control);		/* XXX */

	/* Loopback avoidance and state recovery */
	if (sin) {
		int	len = 0;
		char	*c = sin->sin_zero;

		ip_divert_cookie = sin->sin_port;

		/*
		 * Find receive interface with the given name or IP address.
		 * The name is user supplied data so don't trust it's size or 
		 * that it is zero terminated. The name has priority.
		 * We are presently assuming that the sockaddr_in 
		 * has not been replaced by a sockaddr_div, so we limit it
		 * to 16 bytes in total. the name is stuffed (if it exists)
		 * in the sin_zero[] field.
		 */
		while (*c++ && (len++ < sizeof(sin->sin_zero)));
		if ((len > 0) && (len < sizeof(sin->sin_zero)))
			m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
	} else {
		ip_divert_cookie = 0;
	}

	/* Reinject packet into the system as incoming or outgoing */
	if (!sin || sin->sin_addr.s_addr == 0) {
		/*
		 * Don't allow both user specified and setsockopt options,
		 * and don't allow packet length sizes that will crash
		 */
		if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
		     ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
			error = EINVAL;
			goto cantsend;
		}

		/* Convert fields to host order for ip_output() */
		NTOHS(ip->ip_len);
		NTOHS(ip->ip_off);

		/* Send packet to output processing */
		ipstat.ips_rawout++;			/* XXX */
		error = ip_output(m, inp->inp_options, &inp->inp_route,
			(so->so_options & SO_DONTROUTE) |
			IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions);
	} else {
		struct	ifaddr *ifa;

		/* If no luck with the name above. check by IP address.  */
		if (m->m_pkthdr.rcvif == NULL) {
			/*
			 * Make sure there are no distractions
			 * for ifa_ifwithaddr. Clear the port and the ifname.
			 * Maybe zap all 8 bytes at once using a 64bit write?
			 */
			bzero(sin->sin_zero, sizeof(sin->sin_zero));
			/* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */
			sin->sin_port = 0;
			if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) {
				error = EADDRNOTAVAIL;
				goto cantsend;
			}
			m->m_pkthdr.rcvif = ifa->ifa_ifp;
		}

		/* Send packet to input processing */
		ip_input(m);
	}

	/* paranoid: Reset for next time (and other packets) */
	/* almost definitly already done in the ipfw filter but.. */
	ip_divert_cookie = 0;
	return error;

cantsend:
	ip_divert_cookie = 0;
	m_freem(m);
	return error;
}

static int
div_attach(struct socket *so, int proto, struct proc *p)
{
	struct inpcb *inp;
	int error, s;

	inp  = sotoinpcb(so);
	if (inp)
		panic("div_attach");
	if (p && (error = suser(p)) != 0)
		return error;

	s = splnet();
	error = in_pcballoc(so, &divcbinfo, p);
	splx(s);
	if (error)
		return error;
	error = soreserve(so, div_sendspace, div_recvspace);
	if (error)
		return error;
	inp = (struct inpcb *)so->so_pcb;
	inp->inp_ip_p = proto;
	inp->inp_flags |= INP_HDRINCL;
	/* The socket is always "connected" because
	   we always know "where" to send the packet */
	so->so_state |= SS_ISCONNECTED;
	return 0;
}

static int
div_detach(struct socket *so)
{
	struct inpcb *inp;

	inp = sotoinpcb(so);
	if (inp == 0)
		panic("div_detach");
	in_pcbdetach(inp);
	return 0;
}

static int
div_abort(struct socket *so)
{
	soisdisconnected(so);
	return div_detach(so);
}

static int
div_disconnect(struct socket *so)
{
	if ((so->so_state & SS_ISCONNECTED) == 0)
		return ENOTCONN;
	return div_abort(so);
}

static int
div_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct inpcb *inp;
	int s;
	int error;

	s = splnet();
	inp = sotoinpcb(so);
	error = in_pcbbind(inp, nam, p);
	splx(s);
	return 0;
}

static int
div_shutdown(struct socket *so)
{
	socantsendmore(so);
	return 0;
}

static int
div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
	 struct mbuf *control, struct proc *p)
{
	/* Packet must have a header (but that's about it) */
	if (m->m_len < sizeof (struct ip) ||
	    (m = m_pullup(m, sizeof (struct ip))) == 0) {
		ipstat.ips_toosmall++;
		m_freem(m);
		return EINVAL;
	}

	/* Send packet */
	return div_output(so, m, nam, control);
}

struct pr_usrreqs div_usrreqs = {
	div_abort, pru_accept_notsupp, div_attach, div_bind,
	pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach,
	div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp,
	pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
	in_setsockaddr, sosend, soreceive, sopoll
};
OpenPOWER on IntegriCloud