1
2/*
3 * ng_vjc.c
4 */
5
6/*-
7 * Copyright (c) 1996-1999 Whistle Communications, Inc.
8 * All rights reserved.
9 *
10 * Subject to the following obligations and disclaimer of warranty, use and
11 * redistribution of this software, in source or object code forms, with or
12 * without modifications are expressly permitted by Whistle Communications;
13 * provided, however, that:
14 * 1. Any and all reproductions of the source or object code must include the
15 *    copyright notice above and the following disclaimer of warranties; and
16 * 2. No rights are granted, in any manner or form, to use Whistle
17 *    Communications, Inc. trademarks, including the mark "WHISTLE
18 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
19 *    such appears in the above copyright notice or in the software.
20 *
21 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
22 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
23 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
24 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
26 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
27 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
28 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
29 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
30 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
31 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
32 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
33 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
37 * OF SUCH DAMAGE.
38 *
39 * Author: Archie Cobbs <archie@freebsd.org>
40 *
41 * $FreeBSD$
42 * $Whistle: ng_vjc.c,v 1.17 1999/11/01 09:24:52 julian Exp $
43 */
44
45/*
46 * This node performs Van Jacobson IP header (de)compression.
47 * You must have included net/slcompress.c in your kernel compilation.
48 */
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/errno.h>
53#include <sys/kernel.h>
54#include <sys/mbuf.h>
55#include <sys/malloc.h>
56#include <sys/errno.h>
57
58#include <netgraph/ng_message.h>
59#include <netgraph/netgraph.h>
60#include <netgraph/ng_parse.h>
61#include <netgraph/ng_vjc.h>
62
63#include <netinet/in.h>
64#include <netinet/in_systm.h>
65#include <netinet/ip.h>
66#include <netinet/tcp.h>
67
68#include <net/slcompress.h>
69
70/* Check agreement with slcompress.c */
71#if MAX_STATES != NG_VJC_MAX_CHANNELS
72#error NG_VJC_MAX_CHANNELS must be the same as MAX_STATES
73#endif
74
75/* Maximum length of a compressed TCP VJ header */
76#define MAX_VJHEADER		19
77
78/* Node private data */
79struct ng_vjc_private {
80	struct	ngm_vjc_config conf;
81	struct	slcompress slc;
82	hook_p	ip;
83	hook_p	vjcomp;
84	hook_p	vjuncomp;
85	hook_p	vjip;
86};
87typedef struct ng_vjc_private *priv_p;
88
89#define ERROUT(x)	do { error = (x); goto done; } while (0)
90
91/* Netgraph node methods */
92static ng_constructor_t	ng_vjc_constructor;
93static ng_rcvmsg_t	ng_vjc_rcvmsg;
94static ng_shutdown_t	ng_vjc_shutdown;
95static ng_newhook_t	ng_vjc_newhook;
96static ng_rcvdata_t	ng_vjc_rcvdata;
97static ng_disconnect_t	ng_vjc_disconnect;
98
99/* Helper stuff */
100static struct mbuf *ng_vjc_pulluphdrs(struct mbuf *m, int knownTCP);
101
102/* Parse type for struct ngm_vjc_config */
103static const struct ng_parse_struct_field ng_vjc_config_type_fields[]
104	= NG_VJC_CONFIG_TYPE_INFO;
105static const struct ng_parse_type ng_vjc_config_type = {
106	&ng_parse_struct_type,
107	&ng_vjc_config_type_fields
108};
109
110/* Parse type for the 'last_cs' and 'cs_next' fields in struct slcompress,
111   which are pointers converted to integer indices, so parse them that way. */
112#ifndef __LP64__
113#define NG_VJC_TSTATE_PTR_TYPE	&ng_parse_uint32_type
114#else
115#define NG_VJC_TSTATE_PTR_TYPE	&ng_parse_uint64_type
116#endif
117
118/* Parse type for the 'cs_hdr' field in a struct cstate. Ideally we would
119   like to use a 'struct ip' type instead of a simple array of bytes. */
120static const struct ng_parse_fixedarray_info ng_vjc_cs_hdr_type_info = {
121	&ng_parse_hint8_type,
122	MAX_HDR
123};
124static const struct ng_parse_type ng_vjc_cs_hdr_type = {
125	&ng_parse_fixedarray_type,
126	&ng_vjc_cs_hdr_type_info
127};
128
129/* Parse type for a struct cstate */
130static const struct ng_parse_struct_field ng_vjc_cstate_type_fields[] = {
131	{ "cs_next",		NG_VJC_TSTATE_PTR_TYPE		},
132	{ "cs_hlen",		&ng_parse_uint16_type		},
133	{ "cs_id",		&ng_parse_uint8_type		},
134	{ "cs_filler",		&ng_parse_uint8_type		},
135	{ "cs_hdr",		&ng_vjc_cs_hdr_type		},
136	{ NULL }
137};
138static const struct ng_parse_type ng_vjc_cstate_type = {
139	&ng_parse_struct_type,
140	&ng_vjc_cstate_type_fields
141};
142
143/* Parse type for an array of MAX_STATES struct cstate's, ie, tstate & rstate */
144static const struct ng_parse_fixedarray_info ng_vjc_cstatearray_type_info = {
145	&ng_vjc_cstate_type,
146	MAX_STATES
147};
148static const struct ng_parse_type ng_vjc_cstatearray_type = {
149	&ng_parse_fixedarray_type,
150	&ng_vjc_cstatearray_type_info
151};
152
153/* Parse type for struct slcompress. Keep this in sync with the
154   definition of struct slcompress defined in <net/slcompress.h> */
155static const struct ng_parse_struct_field ng_vjc_slcompress_type_fields[] = {
156	{ "last_cs",		NG_VJC_TSTATE_PTR_TYPE		},
157	{ "last_recv",		&ng_parse_uint8_type		},
158	{ "last_xmit",		&ng_parse_uint8_type		},
159	{ "flags",		&ng_parse_hint16_type		},
160#ifndef SL_NO_STATS
161	{ "sls_packets",	&ng_parse_uint32_type		},
162	{ "sls_compressed",	&ng_parse_uint32_type		},
163	{ "sls_searches",	&ng_parse_uint32_type		},
164	{ "sls_misses",		&ng_parse_uint32_type		},
165	{ "sls_uncompressedin",	&ng_parse_uint32_type		},
166	{ "sls_compressedin",	&ng_parse_uint32_type		},
167	{ "sls_errorin",	&ng_parse_uint32_type		},
168	{ "sls_tossed",		&ng_parse_uint32_type		},
169#endif
170	{ "tstate",		&ng_vjc_cstatearray_type	},
171	{ "rstate",		&ng_vjc_cstatearray_type	},
172	{ NULL }
173};
174static const struct ng_parse_type ng_vjc_slcompress_type = {
175	&ng_parse_struct_type,
176	&ng_vjc_slcompress_type_fields
177};
178
179/* List of commands and how to convert arguments to/from ASCII */
180static const struct ng_cmdlist ng_vjc_cmds[] = {
181	{
182	  NGM_VJC_COOKIE,
183	  NGM_VJC_SET_CONFIG,
184	  "setconfig",
185	  &ng_vjc_config_type,
186	  NULL
187	},
188	{
189	  NGM_VJC_COOKIE,
190	  NGM_VJC_GET_CONFIG,
191	  "getconfig",
192	  NULL,
193	  &ng_vjc_config_type,
194	},
195	{
196	  NGM_VJC_COOKIE,
197	  NGM_VJC_GET_STATE,
198	  "getstate",
199	  NULL,
200	  &ng_vjc_slcompress_type,
201	},
202	{
203	  NGM_VJC_COOKIE,
204	  NGM_VJC_CLR_STATS,
205	  "clrstats",
206	  NULL,
207	  NULL,
208	},
209	{
210	  NGM_VJC_COOKIE,
211	  NGM_VJC_RECV_ERROR,
212	  "recverror",
213	  NULL,
214	  NULL,
215	},
216	{ 0 }
217};
218
219/* Node type descriptor */
220static struct ng_type ng_vjc_typestruct = {
221	.version =	NG_ABI_VERSION,
222	.name =		NG_VJC_NODE_TYPE,
223	.constructor =	ng_vjc_constructor,
224	.rcvmsg =	ng_vjc_rcvmsg,
225	.shutdown =	ng_vjc_shutdown,
226	.newhook =	ng_vjc_newhook,
227	.rcvdata =	ng_vjc_rcvdata,
228	.disconnect =	ng_vjc_disconnect,
229	.cmdlist =	ng_vjc_cmds,
230};
231NETGRAPH_INIT(vjc, &ng_vjc_typestruct);
232
233/************************************************************************
234			NETGRAPH NODE METHODS
235 ************************************************************************/
236
237/*
238 * Create a new node
239 */
240static int
241ng_vjc_constructor(node_p node)
242{
243	priv_p priv;
244
245	/* Allocate private structure */
246	priv = malloc(sizeof(*priv), M_NETGRAPH, M_WAITOK | M_ZERO);
247
248	NG_NODE_SET_PRIVATE(node, priv);
249
250	/* slcompress is not thread-safe. Protect it's state here. */
251	NG_NODE_FORCE_WRITER(node);
252
253	/* Done */
254	return (0);
255}
256
257/*
258 * Add a new hook
259 */
260static int
261ng_vjc_newhook(node_p node, hook_p hook, const char *name)
262{
263	const priv_p priv = NG_NODE_PRIVATE(node);
264	hook_p *hookp;
265
266	/* Get hook */
267	if (strcmp(name, NG_VJC_HOOK_IP) == 0)
268		hookp = &priv->ip;
269	else if (strcmp(name, NG_VJC_HOOK_VJCOMP) == 0)
270		hookp = &priv->vjcomp;
271	else if (strcmp(name, NG_VJC_HOOK_VJUNCOMP) == 0)
272		hookp = &priv->vjuncomp;
273	else if (strcmp(name, NG_VJC_HOOK_VJIP) == 0)
274		hookp = &priv->vjip;
275	else
276		return (EINVAL);
277
278	/* See if already connected */
279	if (*hookp)
280		return (EISCONN);
281
282	/* OK */
283	*hookp = hook;
284	return (0);
285}
286
287/*
288 * Receive a control message
289 */
290static int
291ng_vjc_rcvmsg(node_p node, item_p item, hook_p lasthook)
292{
293	const priv_p priv = NG_NODE_PRIVATE(node);
294	struct ng_mesg *resp = NULL;
295	int error = 0;
296	struct ng_mesg *msg;
297
298	NGI_GET_MSG(item, msg);
299	/* Check type cookie */
300	switch (msg->header.typecookie) {
301	case NGM_VJC_COOKIE:
302		switch (msg->header.cmd) {
303		case NGM_VJC_SET_CONFIG:
304		    {
305			struct ngm_vjc_config *const c =
306				(struct ngm_vjc_config *) msg->data;
307
308			if (msg->header.arglen != sizeof(*c))
309				ERROUT(EINVAL);
310			if ((priv->conf.enableComp || priv->conf.enableDecomp)
311			    && (c->enableComp || c->enableDecomp))
312				ERROUT(EALREADY);
313			if (c->enableComp) {
314				if (c->maxChannel > NG_VJC_MAX_CHANNELS - 1
315				    || c->maxChannel < NG_VJC_MIN_CHANNELS - 1)
316					ERROUT(EINVAL);
317			} else
318				c->maxChannel = NG_VJC_MAX_CHANNELS - 1;
319			if (c->enableComp != 0 || c->enableDecomp != 0) {
320				bzero(&priv->slc, sizeof(priv->slc));
321				sl_compress_init(&priv->slc, c->maxChannel);
322			}
323			priv->conf = *c;
324			break;
325		    }
326		case NGM_VJC_GET_CONFIG:
327		    {
328			struct ngm_vjc_config *conf;
329
330			NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
331			if (resp == NULL)
332				ERROUT(ENOMEM);
333			conf = (struct ngm_vjc_config *)resp->data;
334			*conf = priv->conf;
335			break;
336		    }
337		case NGM_VJC_GET_STATE:
338		    {
339			const struct slcompress *const sl0 = &priv->slc;
340			struct slcompress *sl;
341			u_int16_t index;
342			int i;
343
344			/* Get response structure */
345			NG_MKRESPONSE(resp, msg, sizeof(*sl), M_NOWAIT);
346			if (resp == NULL)
347				ERROUT(ENOMEM);
348			sl = (struct slcompress *)resp->data;
349			*sl = *sl0;
350
351			/* Replace pointers with integer indicies */
352			if (sl->last_cs != NULL) {
353				index = sl0->last_cs - sl0->tstate;
354				bzero(&sl->last_cs, sizeof(sl->last_cs));
355				*((u_int16_t *)&sl->last_cs) = index;
356			}
357			for (i = 0; i < MAX_STATES; i++) {
358				struct cstate *const cs = &sl->tstate[i];
359
360				index = sl0->tstate[i].cs_next - sl0->tstate;
361				bzero(&cs->cs_next, sizeof(cs->cs_next));
362				*((u_int16_t *)&cs->cs_next) = index;
363			}
364			break;
365		    }
366		case NGM_VJC_CLR_STATS:
367			priv->slc.sls_packets = 0;
368			priv->slc.sls_compressed = 0;
369			priv->slc.sls_searches = 0;
370			priv->slc.sls_misses = 0;
371			priv->slc.sls_uncompressedin = 0;
372			priv->slc.sls_compressedin = 0;
373			priv->slc.sls_errorin = 0;
374			priv->slc.sls_tossed = 0;
375			break;
376		case NGM_VJC_RECV_ERROR:
377			sl_uncompress_tcp(NULL, 0, TYPE_ERROR, &priv->slc);
378			break;
379		default:
380			error = EINVAL;
381			break;
382		}
383		break;
384	default:
385		error = EINVAL;
386		break;
387	}
388done:
389	NG_RESPOND_MSG(error, node, item, resp);
390	NG_FREE_MSG(msg);
391	return (error);
392}
393
394/*
395 * Receive data
396 */
397static int
398ng_vjc_rcvdata(hook_p hook, item_p item)
399{
400	const node_p node = NG_HOOK_NODE(hook);
401	const priv_p priv = NG_NODE_PRIVATE(node);
402	int error = 0;
403	struct mbuf *m;
404
405	NGI_GET_M(item, m);
406	if (hook == priv->ip) {			/* outgoing packet */
407		u_int type = TYPE_IP;
408
409		/* Compress packet if enabled and proto is TCP */
410		if (priv->conf.enableComp) {
411			struct ip *ip;
412
413			if ((m = ng_vjc_pulluphdrs(m, 0)) == NULL) {
414				NG_FREE_ITEM(item);
415				return (ENOBUFS);
416			}
417			ip = mtod(m, struct ip *);
418			if (ip->ip_p == IPPROTO_TCP) {
419				const int origLen = m->m_len;
420
421				type = sl_compress_tcp(m, ip,
422				    &priv->slc, priv->conf.compressCID);
423				m->m_pkthdr.len += m->m_len - origLen;
424			}
425		}
426
427		/* Dispatch to the appropriate outgoing hook */
428		switch (type) {
429		case TYPE_IP:
430			hook = priv->vjip;
431			break;
432		case TYPE_UNCOMPRESSED_TCP:
433			hook = priv->vjuncomp;
434			break;
435		case TYPE_COMPRESSED_TCP:
436			hook = priv->vjcomp;
437			break;
438		default:
439			panic("%s: type=%d", __func__, type);
440		}
441	} else if (hook == priv->vjcomp) {	/* incoming compressed packet */
442		int vjlen, need2pullup;
443		struct mbuf *hm;
444		u_char *hdr;
445		u_int hlen;
446
447		/* Are we decompressing? */
448		if (!priv->conf.enableDecomp) {
449			NG_FREE_M(m);
450			NG_FREE_ITEM(item);
451			return (ENXIO);
452		}
453
454		/* Pull up the necessary amount from the mbuf */
455		need2pullup = MAX_VJHEADER;
456		if (need2pullup > m->m_pkthdr.len)
457			need2pullup = m->m_pkthdr.len;
458		if (m->m_len < need2pullup
459		    && (m = m_pullup(m, need2pullup)) == NULL) {
460			priv->slc.sls_errorin++;
461			NG_FREE_ITEM(item);
462			return (ENOBUFS);
463		}
464
465		/* Uncompress packet to reconstruct TCP/IP header */
466		vjlen = sl_uncompress_tcp_core(mtod(m, u_char *),
467		    m->m_len, m->m_pkthdr.len, TYPE_COMPRESSED_TCP,
468		    &priv->slc, &hdr, &hlen);
469		if (vjlen <= 0) {
470			NG_FREE_M(m);
471			NG_FREE_ITEM(item);
472			return (EINVAL);
473		}
474		m_adj(m, vjlen);
475
476		/* Copy the reconstructed TCP/IP headers into a new mbuf */
477		MGETHDR(hm, M_NOWAIT, MT_DATA);
478		if (hm == NULL) {
479			priv->slc.sls_errorin++;
480			NG_FREE_M(m);
481			NG_FREE_ITEM(item);
482			return (ENOBUFS);
483		}
484		hm->m_len = 0;
485		hm->m_pkthdr.rcvif = NULL;
486		if (hlen > MHLEN) {		/* unlikely, but can happen */
487			MCLGET(hm, M_NOWAIT);
488			if ((hm->m_flags & M_EXT) == 0) {
489				m_freem(hm);
490				priv->slc.sls_errorin++;
491				NG_FREE_M(m);
492				NG_FREE_ITEM(item);
493				return (ENOBUFS);
494			}
495		}
496		bcopy(hdr, mtod(hm, u_char *), hlen);
497		hm->m_len = hlen;
498
499		/* Glue TCP/IP headers and rest of packet together */
500		hm->m_next = m;
501		hm->m_pkthdr.len = hlen + m->m_pkthdr.len;
502		m = hm;
503		hook = priv->ip;
504	} else if (hook == priv->vjuncomp) {	/* incoming uncompressed pkt */
505		u_char *hdr;
506		u_int hlen;
507
508		/* Are we decompressing? */
509		if (!priv->conf.enableDecomp) {
510			NG_FREE_M(m);
511			NG_FREE_ITEM(item);
512			return (ENXIO);
513		}
514
515		/* Pull up IP+TCP headers */
516		if ((m = ng_vjc_pulluphdrs(m, 1)) == NULL) {
517			NG_FREE_ITEM(item);
518			return (ENOBUFS);
519		}
520
521		/* Run packet through uncompressor */
522		if (sl_uncompress_tcp_core(mtod(m, u_char *),
523		    m->m_len, m->m_pkthdr.len, TYPE_UNCOMPRESSED_TCP,
524		    &priv->slc, &hdr, &hlen) < 0) {
525			NG_FREE_M(m);
526			NG_FREE_ITEM(item);
527			return (EINVAL);
528		}
529		hook = priv->ip;
530	} else if (hook == priv->vjip)	/* incoming regular packet (bypass) */
531		hook = priv->ip;
532	else
533		panic("%s: unknown hook", __func__);
534
535	/* Send result back out */
536	NG_FWD_NEW_DATA(error, item, hook, m);
537	return (error);
538}
539
540/*
541 * Shutdown node
542 */
543static int
544ng_vjc_shutdown(node_p node)
545{
546	const priv_p priv = NG_NODE_PRIVATE(node);
547
548	bzero(priv, sizeof(*priv));
549	free(priv, M_NETGRAPH);
550	NG_NODE_SET_PRIVATE(node, NULL);
551	NG_NODE_UNREF(node);
552	return (0);
553}
554
555/*
556 * Hook disconnection
557 */
558static int
559ng_vjc_disconnect(hook_p hook)
560{
561	const node_p node = NG_HOOK_NODE(hook);
562	const priv_p priv = NG_NODE_PRIVATE(node);
563
564	/* Zero out hook pointer */
565	if (hook == priv->ip)
566		priv->ip = NULL;
567	else if (hook == priv->vjcomp)
568		priv->vjcomp = NULL;
569	else if (hook == priv->vjuncomp)
570		priv->vjuncomp = NULL;
571	else if (hook == priv->vjip)
572		priv->vjip = NULL;
573	else
574		panic("%s: unknown hook", __func__);
575
576	/* Go away if no hooks left */
577	if ((NG_NODE_NUMHOOKS(node) == 0)
578	&& (NG_NODE_IS_VALID(node)))
579		ng_rmnode_self(node);
580	return (0);
581}
582
583/************************************************************************
584			HELPER STUFF
585 ************************************************************************/
586
587/*
588 * Pull up the full IP and TCP headers of a packet. If packet is not
589 * a TCP packet, just pull up the IP header.
590 */
591static struct mbuf *
592ng_vjc_pulluphdrs(struct mbuf *m, int knownTCP)
593{
594	struct ip *ip;
595	struct tcphdr *tcp;
596	int ihlen, thlen;
597
598	if (m->m_len < sizeof(*ip) && (m = m_pullup(m, sizeof(*ip))) == NULL)
599		return (NULL);
600	ip = mtod(m, struct ip *);
601	if (!knownTCP && ip->ip_p != IPPROTO_TCP)
602		return (m);
603	ihlen = ip->ip_hl << 2;
604	if (m->m_len < ihlen + sizeof(*tcp)) {
605		if ((m = m_pullup(m, ihlen + sizeof(*tcp))) == NULL)
606			return (NULL);
607		ip = mtod(m, struct ip *);
608	}
609	tcp = (struct tcphdr *)((u_char *)ip + ihlen);
610	thlen = tcp->th_off << 2;
611	if (m->m_len < ihlen + thlen)
612		m = m_pullup(m, ihlen + thlen);
613	return (m);
614}
615
616