xref: /freebsd/sys/netgraph/ng_ppp.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /*-
2  * Copyright (c) 1996-2000 Whistle Communications, Inc.
3  * All rights reserved.
4  *
5  * Subject to the following obligations and disclaimer of warranty, use and
6  * redistribution of this software, in source or object code forms, with or
7  * without modifications are expressly permitted by Whistle Communications;
8  * provided, however, that:
9  * 1. Any and all reproductions of the source or object code must include the
10  *    copyright notice above and the following disclaimer of warranties; and
11  * 2. No rights are granted, in any manner or form, to use Whistle
12  *    Communications, Inc. trademarks, including the mark "WHISTLE
13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
14  *    such appears in the above copyright notice or in the software.
15  *
16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
32  * OF SUCH DAMAGE.
33  *
34  * Copyright (c) 2007 Alexander Motin <mav@alkar.net>
35  * All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice unmodified, this list of conditions, and the following
42  *    disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  *
47  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
48  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
51  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
52  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
53  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
54  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
55  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
56  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
57  * SUCH DAMAGE.
58  *
59  * Authors: Archie Cobbs <archie@freebsd.org>, Alexander Motin <mav@alkar.net>
60  *
61  * $FreeBSD$
62  * $Whistle: ng_ppp.c,v 1.24 1999/11/01 09:24:52 julian Exp $
63  */
64 
65 /*
66  * PPP node type data-flow.
67  *
68  *       hook      xmit        layer         recv      hook
69  *              ------------------------------------
70  *       inet ->                                    -> inet
71  *       ipv6 ->                                    -> ipv6
72  *        ipx ->               proto                -> ipx
73  *      atalk ->                                    -> atalk
74  *     bypass ->                                    -> bypass
75  *              -hcomp_xmit()----------proto_recv()-
76  *     vjc_ip <-                                    <- vjc_ip
77  *   vjc_comp ->         header compression         -> vjc_comp
78  * vjc_uncomp ->                                    -> vjc_uncomp
79  *   vjc_vjip ->
80  *              -comp_xmit()-----------hcomp_recv()-
81  *   compress <-            compression             <- decompress
82  *   compress ->                                    -> decompress
83  *              -crypt_xmit()-----------comp_recv()-
84  *    encrypt <-             encryption             <- decrypt
85  *    encrypt ->                                    -> decrypt
86  *              -ml_xmit()-------------crypt_recv()-
87  *                           multilink
88  *              -link_xmit()--------------ml_recv()-
89  *      linkX <-               link                 <- linkX
90  *
91  */
92 
93 #include <sys/param.h>
94 #include <sys/systm.h>
95 #include <sys/kernel.h>
96 #include <sys/limits.h>
97 #include <sys/time.h>
98 #include <sys/mbuf.h>
99 #include <sys/malloc.h>
100 #include <sys/errno.h>
101 #include <sys/ctype.h>
102 
103 #include <netgraph/ng_message.h>
104 #include <netgraph/netgraph.h>
105 #include <netgraph/ng_parse.h>
106 #include <netgraph/ng_ppp.h>
107 #include <netgraph/ng_vjc.h>
108 
109 #ifdef NG_SEPARATE_MALLOC
110 MALLOC_DEFINE(M_NETGRAPH_PPP, "netgraph_ppp", "netgraph ppp node");
111 #else
112 #define M_NETGRAPH_PPP M_NETGRAPH
113 #endif
114 
115 #define PROT_VALID(p)		(((p) & 0x0101) == 0x0001)
116 #define PROT_COMPRESSABLE(p)	(((p) & 0xff00) == 0x0000)
117 
118 /* Some PPP protocol numbers we're interested in */
119 #define PROT_ATALK		0x0029
120 #define PROT_COMPD		0x00fd
121 #define PROT_CRYPTD		0x0053
122 #define PROT_IP			0x0021
123 #define PROT_IPV6		0x0057
124 #define PROT_IPX		0x002b
125 #define PROT_LCP		0xc021
126 #define PROT_MP			0x003d
127 #define PROT_VJCOMP		0x002d
128 #define PROT_VJUNCOMP		0x002f
129 
130 /* Multilink PPP definitions */
131 #define MP_MIN_MRRU		1500		/* per RFC 1990 */
132 #define MP_INITIAL_SEQ		0		/* per RFC 1990 */
133 #define MP_MIN_LINK_MRU		32
134 
135 #define MP_SHORT_SEQ_MASK	0x00000fff	/* short seq # mask */
136 #define MP_SHORT_SEQ_HIBIT	0x00000800	/* short seq # high bit */
137 #define MP_SHORT_FIRST_FLAG	0x00008000	/* first fragment in frame */
138 #define MP_SHORT_LAST_FLAG	0x00004000	/* last fragment in frame */
139 
140 #define MP_LONG_SEQ_MASK	0x00ffffff	/* long seq # mask */
141 #define MP_LONG_SEQ_HIBIT	0x00800000	/* long seq # high bit */
142 #define MP_LONG_FIRST_FLAG	0x80000000	/* first fragment in frame */
143 #define MP_LONG_LAST_FLAG	0x40000000	/* last fragment in frame */
144 
145 #define MP_NOSEQ		0x7fffffff	/* impossible sequence number */
146 
147 /* Sign extension of MP sequence numbers */
148 #define MP_SHORT_EXTEND(s)	(((s) & MP_SHORT_SEQ_HIBIT) ?		\
149 				    ((s) | ~MP_SHORT_SEQ_MASK)		\
150 				    : ((s) & MP_SHORT_SEQ_MASK))
151 #define MP_LONG_EXTEND(s)	(((s) & MP_LONG_SEQ_HIBIT) ?		\
152 				    ((s) | ~MP_LONG_SEQ_MASK)		\
153 				    : ((s) & MP_LONG_SEQ_MASK))
154 
155 /* Comparision of MP sequence numbers. Note: all sequence numbers
156    except priv->xseq are stored with the sign bit extended. */
157 #define MP_SHORT_SEQ_DIFF(x,y)	MP_SHORT_EXTEND((x) - (y))
158 #define MP_LONG_SEQ_DIFF(x,y)	MP_LONG_EXTEND((x) - (y))
159 
160 #define MP_RECV_SEQ_DIFF(priv,x,y)					\
161 				((priv)->conf.recvShortSeq ?		\
162 				    MP_SHORT_SEQ_DIFF((x), (y)) :	\
163 				    MP_LONG_SEQ_DIFF((x), (y)))
164 
165 /* Increment receive sequence number */
166 #define MP_NEXT_RECV_SEQ(priv,seq)					\
167 				((priv)->conf.recvShortSeq ?		\
168 				    MP_SHORT_EXTEND((seq) + 1) :	\
169 				    MP_LONG_EXTEND((seq) + 1))
170 
171 /* Don't fragment transmitted packets to parts smaller than this */
172 #define MP_MIN_FRAG_LEN		32
173 
174 /* Maximum fragment reasssembly queue length */
175 #define MP_MAX_QUEUE_LEN	128
176 
177 /* Fragment queue scanner period */
178 #define MP_FRAGTIMER_INTERVAL	(hz/2)
179 
180 /* Average link overhead. XXX: Should be given by user-level */
181 #define MP_AVERAGE_LINK_OVERHEAD	16
182 
183 /* Keep this equal to ng_ppp_hook_names lower! */
184 #define HOOK_INDEX_MAX		13
185 
186 /* We store incoming fragments this way */
187 struct ng_ppp_frag {
188 	int				seq;		/* fragment seq# */
189 	uint8_t				first;		/* First in packet? */
190 	uint8_t				last;		/* Last in packet? */
191 	struct timeval			timestamp;	/* time of reception */
192 	struct mbuf			*data;		/* Fragment data */
193 	TAILQ_ENTRY(ng_ppp_frag)	f_qent;		/* Fragment queue */
194 };
195 
196 /* Per-link private information */
197 struct ng_ppp_link {
198 	struct ng_ppp_link_conf	conf;		/* link configuration */
199 	struct ng_ppp_link_stat64	stats;	/* link stats */
200 	hook_p			hook;		/* connection to link data */
201 	int32_t			seq;		/* highest rec'd seq# - MSEQ */
202 	uint32_t		latency;	/* calculated link latency */
203 	struct timeval		lastWrite;	/* time of last write for MP */
204 	int			bytesInQueue;	/* bytes in the output queue for MP */
205 };
206 
207 /* Total per-node private information */
208 struct ng_ppp_private {
209 	struct ng_ppp_bund_conf	conf;			/* bundle config */
210 	struct ng_ppp_link_stat64	bundleStats;	/* bundle stats */
211 	struct ng_ppp_link	links[NG_PPP_MAX_LINKS];/* per-link info */
212 	int32_t			xseq;			/* next out MP seq # */
213 	int32_t			mseq;			/* min links[i].seq */
214 	uint16_t		activeLinks[NG_PPP_MAX_LINKS];	/* indicies */
215 	uint16_t		numActiveLinks;		/* how many links up */
216 	uint16_t		lastLink;		/* for round robin */
217 	uint8_t			vjCompHooked;		/* VJ comp hooked up? */
218 	uint8_t			allLinksEqual;		/* all xmit the same? */
219 	hook_p			hooks[HOOK_INDEX_MAX];	/* non-link hooks */
220 	struct ng_ppp_frag	fragsmem[MP_MAX_QUEUE_LEN]; /* fragments storage */
221 	TAILQ_HEAD(ng_ppp_fraglist, ng_ppp_frag)	/* fragment queue */
222 				frags;
223 	TAILQ_HEAD(ng_ppp_fragfreelist, ng_ppp_frag)	/* free fragment queue */
224 				fragsfree;
225 	struct callout		fragTimer;		/* fraq queue check */
226 	struct mtx		rmtx;			/* recv mutex */
227 	struct mtx		xmtx;			/* xmit mutex */
228 };
229 typedef struct ng_ppp_private *priv_p;
230 
231 /* Netgraph node methods */
232 static ng_constructor_t	ng_ppp_constructor;
233 static ng_rcvmsg_t	ng_ppp_rcvmsg;
234 static ng_shutdown_t	ng_ppp_shutdown;
235 static ng_newhook_t	ng_ppp_newhook;
236 static ng_rcvdata_t	ng_ppp_rcvdata;
237 static ng_disconnect_t	ng_ppp_disconnect;
238 
239 static ng_rcvdata_t	ng_ppp_rcvdata_inet;
240 static ng_rcvdata_t	ng_ppp_rcvdata_ipv6;
241 static ng_rcvdata_t	ng_ppp_rcvdata_ipx;
242 static ng_rcvdata_t	ng_ppp_rcvdata_atalk;
243 static ng_rcvdata_t	ng_ppp_rcvdata_bypass;
244 
245 static ng_rcvdata_t	ng_ppp_rcvdata_vjc_ip;
246 static ng_rcvdata_t	ng_ppp_rcvdata_vjc_comp;
247 static ng_rcvdata_t	ng_ppp_rcvdata_vjc_uncomp;
248 static ng_rcvdata_t	ng_ppp_rcvdata_vjc_vjip;
249 
250 static ng_rcvdata_t	ng_ppp_rcvdata_compress;
251 static ng_rcvdata_t	ng_ppp_rcvdata_decompress;
252 
253 static ng_rcvdata_t	ng_ppp_rcvdata_encrypt;
254 static ng_rcvdata_t	ng_ppp_rcvdata_decrypt;
255 
256 /* We use integer indicies to refer to the non-link hooks. */
257 static const struct {
258 	char *const name;
259 	ng_rcvdata_t *fn;
260 } ng_ppp_hook_names[] = {
261 #define HOOK_INDEX_ATALK	0
262 	{ NG_PPP_HOOK_ATALK,	ng_ppp_rcvdata_atalk },
263 #define HOOK_INDEX_BYPASS	1
264 	{ NG_PPP_HOOK_BYPASS,	ng_ppp_rcvdata_bypass },
265 #define HOOK_INDEX_COMPRESS	2
266 	{ NG_PPP_HOOK_COMPRESS,	ng_ppp_rcvdata_compress },
267 #define HOOK_INDEX_ENCRYPT	3
268 	{ NG_PPP_HOOK_ENCRYPT,	ng_ppp_rcvdata_encrypt },
269 #define HOOK_INDEX_DECOMPRESS	4
270 	{ NG_PPP_HOOK_DECOMPRESS, ng_ppp_rcvdata_decompress },
271 #define HOOK_INDEX_DECRYPT	5
272 	{ NG_PPP_HOOK_DECRYPT,	ng_ppp_rcvdata_decrypt },
273 #define HOOK_INDEX_INET		6
274 	{ NG_PPP_HOOK_INET,	ng_ppp_rcvdata_inet },
275 #define HOOK_INDEX_IPX		7
276 	{ NG_PPP_HOOK_IPX,	ng_ppp_rcvdata_ipx },
277 #define HOOK_INDEX_VJC_COMP	8
278 	{ NG_PPP_HOOK_VJC_COMP,	ng_ppp_rcvdata_vjc_comp },
279 #define HOOK_INDEX_VJC_IP	9
280 	{ NG_PPP_HOOK_VJC_IP,	ng_ppp_rcvdata_vjc_ip },
281 #define HOOK_INDEX_VJC_UNCOMP	10
282 	{ NG_PPP_HOOK_VJC_UNCOMP, ng_ppp_rcvdata_vjc_uncomp },
283 #define HOOK_INDEX_VJC_VJIP	11
284 	{ NG_PPP_HOOK_VJC_VJIP,	ng_ppp_rcvdata_vjc_vjip },
285 #define HOOK_INDEX_IPV6		12
286 	{ NG_PPP_HOOK_IPV6,	ng_ppp_rcvdata_ipv6 },
287 	{ NULL, NULL }
288 };
289 
290 /* Helper functions */
291 static int	ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto,
292 		    uint16_t linkNum);
293 static int	ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto);
294 static int	ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto,
295 		    uint16_t linkNum);
296 static int	ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto);
297 static int	ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto,
298 		    uint16_t linkNum);
299 static int	ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto);
300 static int	ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto,
301 		    uint16_t linkNum);
302 static int	ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto);
303 static int	ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto,
304 		    uint16_t linkNum);
305 static int	ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto,
306 		    uint16_t linkNum, int plen);
307 
308 static int	ng_ppp_bypass(node_p node, item_p item, uint16_t proto,
309 		    uint16_t linkNum);
310 
311 static void	ng_ppp_bump_mseq(node_p node, int32_t new_mseq);
312 static int	ng_ppp_frag_drop(node_p node);
313 static int	ng_ppp_check_packet(node_p node);
314 static void	ng_ppp_get_packet(node_p node, struct mbuf **mp);
315 static int	ng_ppp_frag_process(node_p node, item_p oitem);
316 static int	ng_ppp_frag_trim(node_p node);
317 static void	ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1,
318 		    int arg2);
319 static void	ng_ppp_frag_checkstale(node_p node);
320 static void	ng_ppp_frag_reset(node_p node);
321 static void	ng_ppp_mp_strategy(node_p node, int len, int *distrib);
322 static int	ng_ppp_intcmp(void *latency, const void *v1, const void *v2);
323 static struct mbuf *ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK);
324 static struct mbuf *ng_ppp_cutproto(struct mbuf *m, uint16_t *proto);
325 static struct mbuf *ng_ppp_prepend(struct mbuf *m, const void *buf, int len);
326 static int	ng_ppp_config_valid(node_p node,
327 		    const struct ng_ppp_node_conf *newConf);
328 static void	ng_ppp_update(node_p node, int newConf);
329 static void	ng_ppp_start_frag_timer(node_p node);
330 static void	ng_ppp_stop_frag_timer(node_p node);
331 
332 /* Parse type for struct ng_ppp_mp_state_type */
333 static const struct ng_parse_fixedarray_info ng_ppp_rseq_array_info = {
334 	&ng_parse_hint32_type,
335 	NG_PPP_MAX_LINKS
336 };
337 static const struct ng_parse_type ng_ppp_rseq_array_type = {
338 	&ng_parse_fixedarray_type,
339 	&ng_ppp_rseq_array_info,
340 };
341 static const struct ng_parse_struct_field ng_ppp_mp_state_type_fields[]
342 	= NG_PPP_MP_STATE_TYPE_INFO(&ng_ppp_rseq_array_type);
343 static const struct ng_parse_type ng_ppp_mp_state_type = {
344 	&ng_parse_struct_type,
345 	&ng_ppp_mp_state_type_fields
346 };
347 
348 /* Parse type for struct ng_ppp_link_conf */
349 static const struct ng_parse_struct_field ng_ppp_link_type_fields[]
350 	= NG_PPP_LINK_TYPE_INFO;
351 static const struct ng_parse_type ng_ppp_link_type = {
352 	&ng_parse_struct_type,
353 	&ng_ppp_link_type_fields
354 };
355 
356 /* Parse type for struct ng_ppp_bund_conf */
357 static const struct ng_parse_struct_field ng_ppp_bund_type_fields[]
358 	= NG_PPP_BUND_TYPE_INFO;
359 static const struct ng_parse_type ng_ppp_bund_type = {
360 	&ng_parse_struct_type,
361 	&ng_ppp_bund_type_fields
362 };
363 
364 /* Parse type for struct ng_ppp_node_conf */
365 static const struct ng_parse_fixedarray_info ng_ppp_array_info = {
366 	&ng_ppp_link_type,
367 	NG_PPP_MAX_LINKS
368 };
369 static const struct ng_parse_type ng_ppp_link_array_type = {
370 	&ng_parse_fixedarray_type,
371 	&ng_ppp_array_info,
372 };
373 static const struct ng_parse_struct_field ng_ppp_conf_type_fields[]
374 	= NG_PPP_CONFIG_TYPE_INFO(&ng_ppp_bund_type, &ng_ppp_link_array_type);
375 static const struct ng_parse_type ng_ppp_conf_type = {
376 	&ng_parse_struct_type,
377 	&ng_ppp_conf_type_fields
378 };
379 
380 /* Parse type for struct ng_ppp_link_stat */
381 static const struct ng_parse_struct_field ng_ppp_stats_type_fields[]
382 	= NG_PPP_STATS_TYPE_INFO;
383 static const struct ng_parse_type ng_ppp_stats_type = {
384 	&ng_parse_struct_type,
385 	&ng_ppp_stats_type_fields
386 };
387 
388 /* Parse type for struct ng_ppp_link_stat64 */
389 static const struct ng_parse_struct_field ng_ppp_stats64_type_fields[]
390 	= NG_PPP_STATS64_TYPE_INFO;
391 static const struct ng_parse_type ng_ppp_stats64_type = {
392 	&ng_parse_struct_type,
393 	&ng_ppp_stats64_type_fields
394 };
395 
396 /* List of commands and how to convert arguments to/from ASCII */
397 static const struct ng_cmdlist ng_ppp_cmds[] = {
398 	{
399 	  NGM_PPP_COOKIE,
400 	  NGM_PPP_SET_CONFIG,
401 	  "setconfig",
402 	  &ng_ppp_conf_type,
403 	  NULL
404 	},
405 	{
406 	  NGM_PPP_COOKIE,
407 	  NGM_PPP_GET_CONFIG,
408 	  "getconfig",
409 	  NULL,
410 	  &ng_ppp_conf_type
411 	},
412 	{
413 	  NGM_PPP_COOKIE,
414 	  NGM_PPP_GET_MP_STATE,
415 	  "getmpstate",
416 	  NULL,
417 	  &ng_ppp_mp_state_type
418 	},
419 	{
420 	  NGM_PPP_COOKIE,
421 	  NGM_PPP_GET_LINK_STATS,
422 	  "getstats",
423 	  &ng_parse_int16_type,
424 	  &ng_ppp_stats_type
425 	},
426 	{
427 	  NGM_PPP_COOKIE,
428 	  NGM_PPP_CLR_LINK_STATS,
429 	  "clrstats",
430 	  &ng_parse_int16_type,
431 	  NULL
432 	},
433 	{
434 	  NGM_PPP_COOKIE,
435 	  NGM_PPP_GETCLR_LINK_STATS,
436 	  "getclrstats",
437 	  &ng_parse_int16_type,
438 	  &ng_ppp_stats_type
439 	},
440 	{
441 	  NGM_PPP_COOKIE,
442 	  NGM_PPP_GET_LINK_STATS64,
443 	  "getstats64",
444 	  &ng_parse_int16_type,
445 	  &ng_ppp_stats64_type
446 	},
447 	{
448 	  NGM_PPP_COOKIE,
449 	  NGM_PPP_GETCLR_LINK_STATS64,
450 	  "getclrstats64",
451 	  &ng_parse_int16_type,
452 	  &ng_ppp_stats64_type
453 	},
454 	{ 0 }
455 };
456 
457 /* Node type descriptor */
458 static struct ng_type ng_ppp_typestruct = {
459 	.version =	NG_ABI_VERSION,
460 	.name =		NG_PPP_NODE_TYPE,
461 	.constructor =	ng_ppp_constructor,
462 	.rcvmsg =	ng_ppp_rcvmsg,
463 	.shutdown =	ng_ppp_shutdown,
464 	.newhook =	ng_ppp_newhook,
465 	.rcvdata =	ng_ppp_rcvdata,
466 	.disconnect =	ng_ppp_disconnect,
467 	.cmdlist =	ng_ppp_cmds,
468 };
469 NETGRAPH_INIT(ppp, &ng_ppp_typestruct);
470 
471 /* Address and control field header */
472 static const uint8_t ng_ppp_acf[2] = { 0xff, 0x03 };
473 
474 /* Maximum time we'll let a complete incoming packet sit in the queue */
475 static const struct timeval ng_ppp_max_staleness = { 2, 0 };	/* 2 seconds */
476 
477 #define ERROUT(x)	do { error = (x); goto done; } while (0)
478 
479 /************************************************************************
480 			NETGRAPH NODE STUFF
481  ************************************************************************/
482 
483 /*
484  * Node type constructor
485  */
486 static int
487 ng_ppp_constructor(node_p node)
488 {
489 	priv_p priv;
490 	int i;
491 
492 	/* Allocate private structure */
493 	MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_PPP, M_NOWAIT | M_ZERO);
494 	if (priv == NULL)
495 		return (ENOMEM);
496 
497 	NG_NODE_SET_PRIVATE(node, priv);
498 
499 	/* Initialize state */
500 	TAILQ_INIT(&priv->frags);
501 	TAILQ_INIT(&priv->fragsfree);
502 	for (i = 0; i < MP_MAX_QUEUE_LEN; i++)
503 		TAILQ_INSERT_TAIL(&priv->fragsfree, &priv->fragsmem[i], f_qent);
504 	for (i = 0; i < NG_PPP_MAX_LINKS; i++)
505 		priv->links[i].seq = MP_NOSEQ;
506 	ng_callout_init(&priv->fragTimer);
507 
508 	mtx_init(&priv->rmtx, "ng_ppp_recv", NULL, MTX_DEF);
509 	mtx_init(&priv->xmtx, "ng_ppp_xmit", NULL, MTX_DEF);
510 
511 	/* Done */
512 	return (0);
513 }
514 
515 /*
516  * Give our OK for a hook to be added
517  */
518 static int
519 ng_ppp_newhook(node_p node, hook_p hook, const char *name)
520 {
521 	const priv_p priv = NG_NODE_PRIVATE(node);
522 	hook_p *hookPtr = NULL;
523 	int linkNum = -1;
524 	int hookIndex = -1;
525 
526 	/* Figure out which hook it is */
527 	if (strncmp(name, NG_PPP_HOOK_LINK_PREFIX,	/* a link hook? */
528 	    strlen(NG_PPP_HOOK_LINK_PREFIX)) == 0) {
529 		const char *cp;
530 		char *eptr;
531 
532 		cp = name + strlen(NG_PPP_HOOK_LINK_PREFIX);
533 		if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
534 			return (EINVAL);
535 		linkNum = (int)strtoul(cp, &eptr, 10);
536 		if (*eptr != '\0' || linkNum < 0 || linkNum >= NG_PPP_MAX_LINKS)
537 			return (EINVAL);
538 		hookPtr = &priv->links[linkNum].hook;
539 		hookIndex = ~linkNum;
540 
541 		/* See if hook is already connected. */
542 		if (*hookPtr != NULL)
543 			return (EISCONN);
544 
545 		/* Disallow more than one link unless multilink is enabled. */
546 		if (priv->links[linkNum].conf.enableLink &&
547 		    !priv->conf.enableMultilink && priv->numActiveLinks >= 1)
548 			return (ENODEV);
549 
550 	} else {				/* must be a non-link hook */
551 		int i;
552 
553 		for (i = 0; ng_ppp_hook_names[i].name != NULL; i++) {
554 			if (strcmp(name, ng_ppp_hook_names[i].name) == 0) {
555 				hookPtr = &priv->hooks[i];
556 				hookIndex = i;
557 				break;
558 			}
559 		}
560 		if (ng_ppp_hook_names[i].name == NULL)
561 			return (EINVAL);	/* no such hook */
562 
563 		/* See if hook is already connected */
564 		if (*hookPtr != NULL)
565 			return (EISCONN);
566 
567 		/* Every non-linkX hook have it's own function. */
568 		NG_HOOK_SET_RCVDATA(hook, ng_ppp_hook_names[i].fn);
569 	}
570 
571 	/* OK */
572 	*hookPtr = hook;
573 	NG_HOOK_SET_PRIVATE(hook, (void *)(intptr_t)hookIndex);
574 	ng_ppp_update(node, 0);
575 	return (0);
576 }
577 
578 /*
579  * Receive a control message
580  */
581 static int
582 ng_ppp_rcvmsg(node_p node, item_p item, hook_p lasthook)
583 {
584 	const priv_p priv = NG_NODE_PRIVATE(node);
585 	struct ng_mesg *resp = NULL;
586 	int error = 0;
587 	struct ng_mesg *msg;
588 
589 	NGI_GET_MSG(item, msg);
590 	switch (msg->header.typecookie) {
591 	case NGM_PPP_COOKIE:
592 		switch (msg->header.cmd) {
593 		case NGM_PPP_SET_CONFIG:
594 		    {
595 			struct ng_ppp_node_conf *const conf =
596 			    (struct ng_ppp_node_conf *)msg->data;
597 			int i;
598 
599 			/* Check for invalid or illegal config */
600 			if (msg->header.arglen != sizeof(*conf))
601 				ERROUT(EINVAL);
602 			if (!ng_ppp_config_valid(node, conf))
603 				ERROUT(EINVAL);
604 
605 			/* Copy config */
606 			priv->conf = conf->bund;
607 			for (i = 0; i < NG_PPP_MAX_LINKS; i++)
608 				priv->links[i].conf = conf->links[i];
609 			ng_ppp_update(node, 1);
610 			break;
611 		    }
612 		case NGM_PPP_GET_CONFIG:
613 		    {
614 			struct ng_ppp_node_conf *conf;
615 			int i;
616 
617 			NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
618 			if (resp == NULL)
619 				ERROUT(ENOMEM);
620 			conf = (struct ng_ppp_node_conf *)resp->data;
621 			conf->bund = priv->conf;
622 			for (i = 0; i < NG_PPP_MAX_LINKS; i++)
623 				conf->links[i] = priv->links[i].conf;
624 			break;
625 		    }
626 		case NGM_PPP_GET_MP_STATE:
627 		    {
628 			struct ng_ppp_mp_state *info;
629 			int i;
630 
631 			NG_MKRESPONSE(resp, msg, sizeof(*info), M_NOWAIT);
632 			if (resp == NULL)
633 				ERROUT(ENOMEM);
634 			info = (struct ng_ppp_mp_state *)resp->data;
635 			bzero(info, sizeof(*info));
636 			for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
637 				if (priv->links[i].seq != MP_NOSEQ)
638 					info->rseq[i] = priv->links[i].seq;
639 			}
640 			info->mseq = priv->mseq;
641 			info->xseq = priv->xseq;
642 			break;
643 		    }
644 		case NGM_PPP_GET_LINK_STATS:
645 		case NGM_PPP_CLR_LINK_STATS:
646 		case NGM_PPP_GETCLR_LINK_STATS:
647 		case NGM_PPP_GET_LINK_STATS64:
648 		case NGM_PPP_GETCLR_LINK_STATS64:
649 		    {
650 			struct ng_ppp_link_stat64 *stats;
651 			uint16_t linkNum;
652 
653 			/* Process request. */
654 			if (msg->header.arglen != sizeof(uint16_t))
655 				ERROUT(EINVAL);
656 			linkNum = *((uint16_t *) msg->data);
657 			if (linkNum >= NG_PPP_MAX_LINKS
658 			    && linkNum != NG_PPP_BUNDLE_LINKNUM)
659 				ERROUT(EINVAL);
660 			stats = (linkNum == NG_PPP_BUNDLE_LINKNUM) ?
661 			    &priv->bundleStats : &priv->links[linkNum].stats;
662 
663 			/* Make 64bit reply. */
664 			if (msg->header.cmd == NGM_PPP_GET_LINK_STATS64 ||
665 			    msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS64) {
666 				NG_MKRESPONSE(resp, msg,
667 				    sizeof(struct ng_ppp_link_stat64), M_NOWAIT);
668 				if (resp == NULL)
669 					ERROUT(ENOMEM);
670 				bcopy(stats, resp->data, sizeof(*stats));
671 			} else
672 			/* Make 32bit reply. */
673 			if (msg->header.cmd == NGM_PPP_GET_LINK_STATS ||
674 			    msg->header.cmd == NGM_PPP_GETCLR_LINK_STATS) {
675 				struct ng_ppp_link_stat *rs;
676 				NG_MKRESPONSE(resp, msg,
677 				    sizeof(struct ng_ppp_link_stat), M_NOWAIT);
678 				if (resp == NULL)
679 					ERROUT(ENOMEM);
680 				rs = (struct ng_ppp_link_stat *)resp->data;
681 				/* Truncate 64->32 bits. */
682 				rs->xmitFrames = stats->xmitFrames;
683 				rs->xmitOctets = stats->xmitOctets;
684 				rs->recvFrames = stats->recvFrames;
685 				rs->recvOctets = stats->recvOctets;
686 				rs->badProtos = stats->badProtos;
687 				rs->runts = stats->runts;
688 				rs->dupFragments = stats->dupFragments;
689 				rs->dropFragments = stats->dropFragments;
690 			}
691 			/* Clear stats. */
692 			if (msg->header.cmd != NGM_PPP_GET_LINK_STATS &&
693 			    msg->header.cmd != NGM_PPP_GET_LINK_STATS64)
694 				bzero(stats, sizeof(*stats));
695 			break;
696 		    }
697 		default:
698 			error = EINVAL;
699 			break;
700 		}
701 		break;
702 	case NGM_VJC_COOKIE:
703 	    {
704 		/*
705 		 * Forward it to the vjc node. leave the
706 		 * old return address alone.
707 		 * If we have no hook, let NG_RESPOND_MSG
708 		 * clean up any remaining resources.
709 		 * Because we have no resp, the item will be freed
710 		 * along with anything it references. Don't
711 		 * let msg be freed twice.
712 		 */
713 		NGI_MSG(item) = msg;	/* put it back in the item */
714 		msg = NULL;
715 		if ((lasthook = priv->hooks[HOOK_INDEX_VJC_IP])) {
716 			NG_FWD_ITEM_HOOK(error, item, lasthook);
717 		}
718 		return (error);
719 	    }
720 	default:
721 		error = EINVAL;
722 		break;
723 	}
724 done:
725 	NG_RESPOND_MSG(error, node, item, resp);
726 	NG_FREE_MSG(msg);
727 	return (error);
728 }
729 
730 /*
731  * Destroy node
732  */
733 static int
734 ng_ppp_shutdown(node_p node)
735 {
736 	const priv_p priv = NG_NODE_PRIVATE(node);
737 
738 	/* Stop fragment queue timer */
739 	ng_ppp_stop_frag_timer(node);
740 
741 	/* Take down netgraph node */
742 	ng_ppp_frag_reset(node);
743 	mtx_destroy(&priv->rmtx);
744 	mtx_destroy(&priv->xmtx);
745 	bzero(priv, sizeof(*priv));
746 	FREE(priv, M_NETGRAPH_PPP);
747 	NG_NODE_SET_PRIVATE(node, NULL);
748 	NG_NODE_UNREF(node);		/* let the node escape */
749 	return (0);
750 }
751 
752 /*
753  * Hook disconnection
754  */
755 static int
756 ng_ppp_disconnect(hook_p hook)
757 {
758 	const node_p node = NG_HOOK_NODE(hook);
759 	const priv_p priv = NG_NODE_PRIVATE(node);
760 	const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
761 
762 	/* Zero out hook pointer */
763 	if (index < 0)
764 		priv->links[~index].hook = NULL;
765 	else
766 		priv->hooks[index] = NULL;
767 
768 	/* Update derived info (or go away if no hooks left). */
769 	if (NG_NODE_NUMHOOKS(node) > 0)
770 		ng_ppp_update(node, 0);
771 	else if (NG_NODE_IS_VALID(node))
772 		ng_rmnode_self(node);
773 
774 	return (0);
775 }
776 
777 /*
778  * Proto layer
779  */
780 
781 /*
782  * Receive data on a hook inet.
783  */
784 static int
785 ng_ppp_rcvdata_inet(hook_p hook, item_p item)
786 {
787 	const node_p node = NG_HOOK_NODE(hook);
788 	const priv_p priv = NG_NODE_PRIVATE(node);
789 
790 	if (!priv->conf.enableIP) {
791 		NG_FREE_ITEM(item);
792 		return (ENXIO);
793 	}
794 	return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IP));
795 }
796 
797 /*
798  * Receive data on a hook ipv6.
799  */
800 static int
801 ng_ppp_rcvdata_ipv6(hook_p hook, item_p item)
802 {
803 	const node_p node = NG_HOOK_NODE(hook);
804 	const priv_p priv = NG_NODE_PRIVATE(node);
805 
806 	if (!priv->conf.enableIPv6) {
807 		NG_FREE_ITEM(item);
808 		return (ENXIO);
809 	}
810 	return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPV6));
811 }
812 
813 /*
814  * Receive data on a hook atalk.
815  */
816 static int
817 ng_ppp_rcvdata_atalk(hook_p hook, item_p item)
818 {
819 	const node_p node = NG_HOOK_NODE(hook);
820 	const priv_p priv = NG_NODE_PRIVATE(node);
821 
822 	if (!priv->conf.enableAtalk) {
823 		NG_FREE_ITEM(item);
824 		return (ENXIO);
825 	}
826 	return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_ATALK));
827 }
828 
829 /*
830  * Receive data on a hook ipx
831  */
832 static int
833 ng_ppp_rcvdata_ipx(hook_p hook, item_p item)
834 {
835 	const node_p node = NG_HOOK_NODE(hook);
836 	const priv_p priv = NG_NODE_PRIVATE(node);
837 
838 	if (!priv->conf.enableIPX) {
839 		NG_FREE_ITEM(item);
840 		return (ENXIO);
841 	}
842 	return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, PROT_IPX));
843 }
844 
845 /*
846  * Receive data on a hook bypass
847  */
848 static int
849 ng_ppp_rcvdata_bypass(hook_p hook, item_p item)
850 {
851 	uint16_t linkNum;
852 	uint16_t proto;
853 	struct mbuf *m;
854 
855 	NGI_GET_M(item, m);
856 	if (m->m_pkthdr.len < 4) {
857 		NG_FREE_ITEM(item);
858 		return (EINVAL);
859 	}
860 	if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
861 		NG_FREE_ITEM(item);
862 		return (ENOBUFS);
863 	}
864 	linkNum = ntohs(mtod(m, uint16_t *)[0]);
865 	proto = ntohs(mtod(m, uint16_t *)[1]);
866 	m_adj(m, 4);
867 	NGI_M(item) = m;
868 
869 	if (linkNum == NG_PPP_BUNDLE_LINKNUM)
870 		return (ng_ppp_hcomp_xmit(NG_HOOK_NODE(hook), item, proto));
871 	else
872 		return (ng_ppp_link_xmit(NG_HOOK_NODE(hook), item, proto,
873 		    linkNum, 0));
874 }
875 
876 static int
877 ng_ppp_bypass(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
878 {
879 	const priv_p priv = NG_NODE_PRIVATE(node);
880 	uint16_t hdr[2];
881 	struct mbuf *m;
882 	int error;
883 
884 	if (priv->hooks[HOOK_INDEX_BYPASS] == NULL) {
885 	    NG_FREE_ITEM(item);
886 	    return (ENXIO);
887 	}
888 
889 	/* Add 4-byte bypass header. */
890 	hdr[0] = htons(linkNum);
891 	hdr[1] = htons(proto);
892 
893 	NGI_GET_M(item, m);
894 	if ((m = ng_ppp_prepend(m, &hdr, 4)) == NULL) {
895 		NG_FREE_ITEM(item);
896 		return (ENOBUFS);
897 	}
898 	NGI_M(item) = m;
899 
900 	/* Send packet out hook. */
901 	NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_BYPASS]);
902 	return (error);
903 }
904 
905 static int
906 ng_ppp_proto_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
907 {
908 	const priv_p priv = NG_NODE_PRIVATE(node);
909 	hook_p outHook = NULL;
910 	int error;
911 
912 	switch (proto) {
913 	    case PROT_IP:
914 		if (priv->conf.enableIP)
915 		    outHook = priv->hooks[HOOK_INDEX_INET];
916 		break;
917 	    case PROT_IPV6:
918 		if (priv->conf.enableIPv6)
919 		    outHook = priv->hooks[HOOK_INDEX_IPV6];
920 		break;
921 	    case PROT_ATALK:
922 		if (priv->conf.enableAtalk)
923 		    outHook = priv->hooks[HOOK_INDEX_ATALK];
924 		break;
925 	    case PROT_IPX:
926 		if (priv->conf.enableIPX)
927 		    outHook = priv->hooks[HOOK_INDEX_IPX];
928 		break;
929 	}
930 
931 	if (outHook == NULL)
932 		return (ng_ppp_bypass(node, item, proto, linkNum));
933 
934 	/* Send packet out hook. */
935 	NG_FWD_ITEM_HOOK(error, item, outHook);
936 	return (error);
937 }
938 
939 /*
940  * Header compression layer
941  */
942 
943 static int
944 ng_ppp_hcomp_xmit(node_p node, item_p item, uint16_t proto)
945 {
946 	const priv_p priv = NG_NODE_PRIVATE(node);
947 
948 	if (proto == PROT_IP &&
949 	    priv->conf.enableVJCompression &&
950 	    priv->vjCompHooked) {
951 		int error;
952 
953 		/* Send packet out hook. */
954 		NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_VJC_IP]);
955 		return (error);
956 	}
957 
958 	return (ng_ppp_comp_xmit(node, item, proto));
959 }
960 
961 /*
962  * Receive data on a hook vjc_comp.
963  */
964 static int
965 ng_ppp_rcvdata_vjc_comp(hook_p hook, item_p item)
966 {
967 	const node_p node = NG_HOOK_NODE(hook);
968 	const priv_p priv = NG_NODE_PRIVATE(node);
969 
970 	if (!priv->conf.enableVJCompression) {
971 		NG_FREE_ITEM(item);
972 		return (ENXIO);
973 	}
974 	return (ng_ppp_comp_xmit(node, item, PROT_VJCOMP));
975 }
976 
977 /*
978  * Receive data on a hook vjc_uncomp.
979  */
980 static int
981 ng_ppp_rcvdata_vjc_uncomp(hook_p hook, item_p item)
982 {
983 	const node_p node = NG_HOOK_NODE(hook);
984 	const priv_p priv = NG_NODE_PRIVATE(node);
985 
986 	if (!priv->conf.enableVJCompression) {
987 		NG_FREE_ITEM(item);
988 		return (ENXIO);
989 	}
990 	return (ng_ppp_comp_xmit(node, item, PROT_VJUNCOMP));
991 }
992 
993 /*
994  * Receive data on a hook vjc_vjip.
995  */
996 static int
997 ng_ppp_rcvdata_vjc_vjip(hook_p hook, item_p item)
998 {
999 	const node_p node = NG_HOOK_NODE(hook);
1000 	const priv_p priv = NG_NODE_PRIVATE(node);
1001 
1002 	if (!priv->conf.enableVJCompression) {
1003 		NG_FREE_ITEM(item);
1004 		return (ENXIO);
1005 	}
1006 	return (ng_ppp_comp_xmit(node, item, PROT_IP));
1007 }
1008 
1009 static int
1010 ng_ppp_hcomp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
1011 {
1012 	const priv_p priv = NG_NODE_PRIVATE(node);
1013 
1014 	if (priv->conf.enableVJDecompression && priv->vjCompHooked) {
1015 		hook_p outHook = NULL;
1016 
1017 		switch (proto) {
1018 		    case PROT_VJCOMP:
1019 			outHook = priv->hooks[HOOK_INDEX_VJC_COMP];
1020 			break;
1021 		    case PROT_VJUNCOMP:
1022 			outHook = priv->hooks[HOOK_INDEX_VJC_UNCOMP];
1023 			break;
1024 		}
1025 
1026 		if (outHook) {
1027 			int error;
1028 
1029 			/* Send packet out hook. */
1030 			NG_FWD_ITEM_HOOK(error, item, outHook);
1031 			return (error);
1032 		}
1033 	}
1034 
1035 	return (ng_ppp_proto_recv(node, item, proto, linkNum));
1036 }
1037 
1038 /*
1039  * Receive data on a hook vjc_ip.
1040  */
1041 static int
1042 ng_ppp_rcvdata_vjc_ip(hook_p hook, item_p item)
1043 {
1044 	const node_p node = NG_HOOK_NODE(hook);
1045 	const priv_p priv = NG_NODE_PRIVATE(node);
1046 
1047 	if (!priv->conf.enableVJDecompression) {
1048 		NG_FREE_ITEM(item);
1049 		return (ENXIO);
1050 	}
1051 	return (ng_ppp_proto_recv(node, item, PROT_IP, NG_PPP_BUNDLE_LINKNUM));
1052 }
1053 
1054 /*
1055  * Compression layer
1056  */
1057 
1058 static int
1059 ng_ppp_comp_xmit(node_p node, item_p item, uint16_t proto)
1060 {
1061 	const priv_p priv = NG_NODE_PRIVATE(node);
1062 
1063 	if (priv->conf.enableCompression &&
1064 	    proto < 0x4000 &&
1065 	    proto != PROT_COMPD &&
1066 	    proto != PROT_CRYPTD &&
1067 	    priv->hooks[HOOK_INDEX_COMPRESS] != NULL) {
1068 	        struct mbuf *m;
1069 		int error;
1070 
1071 	        NGI_GET_M(item, m);
1072 		if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
1073 			NG_FREE_ITEM(item);
1074 			return (ENOBUFS);
1075 		}
1076 		NGI_M(item) = m;
1077 
1078 		/* Send packet out hook. */
1079 		NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_COMPRESS]);
1080 		return (error);
1081 	}
1082 
1083 	return (ng_ppp_crypt_xmit(node, item, proto));
1084 }
1085 
1086 /*
1087  * Receive data on a hook compress.
1088  */
1089 static int
1090 ng_ppp_rcvdata_compress(hook_p hook, item_p item)
1091 {
1092 	const node_p node = NG_HOOK_NODE(hook);
1093 	const priv_p priv = NG_NODE_PRIVATE(node);
1094 	uint16_t proto;
1095 
1096 	switch (priv->conf.enableCompression) {
1097 	    case NG_PPP_COMPRESS_NONE:
1098 		NG_FREE_ITEM(item);
1099 		return (ENXIO);
1100 	    case NG_PPP_COMPRESS_FULL:
1101 		{
1102 			struct mbuf *m;
1103 
1104 			NGI_GET_M(item, m);
1105 			if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
1106 				NG_FREE_ITEM(item);
1107 				return (EIO);
1108 			}
1109 			NGI_M(item) = m;
1110 			if (!PROT_VALID(proto)) {
1111 				NG_FREE_ITEM(item);
1112 				return (EIO);
1113 			}
1114 		}
1115 		break;
1116 	    default:
1117 		proto = PROT_COMPD;
1118 		break;
1119 	}
1120 	return (ng_ppp_crypt_xmit(node, item, proto));
1121 }
1122 
1123 static int
1124 ng_ppp_comp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
1125 {
1126 	const priv_p priv = NG_NODE_PRIVATE(node);
1127 
1128 	if (proto < 0x4000 &&
1129 	    ((proto == PROT_COMPD && priv->conf.enableDecompression) ||
1130 	    priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) &&
1131 	    priv->hooks[HOOK_INDEX_DECOMPRESS] != NULL) {
1132 		int error;
1133 
1134 		if (priv->conf.enableDecompression == NG_PPP_DECOMPRESS_FULL) {
1135 			struct mbuf *m;
1136 			NGI_GET_M(item, m);
1137 			if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
1138 				NG_FREE_ITEM(item);
1139 				return (EIO);
1140 			}
1141 			NGI_M(item) = m;
1142 		}
1143 
1144 		/* Send packet out hook. */
1145 		NG_FWD_ITEM_HOOK(error, item,
1146 		    priv->hooks[HOOK_INDEX_DECOMPRESS]);
1147 		return (error);
1148 	} else if (proto == PROT_COMPD) {
1149 		/* Disabled protos MUST be silently discarded, but
1150 		 * unsupported MUST not. Let user-level decide this. */
1151 		return (ng_ppp_bypass(node, item, proto, linkNum));
1152 	}
1153 
1154 	return (ng_ppp_hcomp_recv(node, item, proto, linkNum));
1155 }
1156 
1157 /*
1158  * Receive data on a hook decompress.
1159  */
1160 static int
1161 ng_ppp_rcvdata_decompress(hook_p hook, item_p item)
1162 {
1163 	const node_p node = NG_HOOK_NODE(hook);
1164 	const priv_p priv = NG_NODE_PRIVATE(node);
1165 	uint16_t proto;
1166 	struct mbuf *m;
1167 
1168 	if (!priv->conf.enableDecompression) {
1169 		NG_FREE_ITEM(item);
1170 		return (ENXIO);
1171 	}
1172 	NGI_GET_M(item, m);
1173 	if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
1174 	        NG_FREE_ITEM(item);
1175 	        return (EIO);
1176 	}
1177 	NGI_M(item) = m;
1178 	if (!PROT_VALID(proto)) {
1179 		priv->bundleStats.badProtos++;
1180 		NG_FREE_ITEM(item);
1181 		return (EIO);
1182 	}
1183 	return (ng_ppp_hcomp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
1184 }
1185 
1186 /*
1187  * Encryption layer
1188  */
1189 
1190 static int
1191 ng_ppp_crypt_xmit(node_p node, item_p item, uint16_t proto)
1192 {
1193 	const priv_p priv = NG_NODE_PRIVATE(node);
1194 
1195 	if (priv->conf.enableEncryption &&
1196 	    proto < 0x4000 &&
1197 	    proto != PROT_CRYPTD &&
1198 	    priv->hooks[HOOK_INDEX_ENCRYPT] != NULL) {
1199 		struct mbuf *m;
1200 		int error;
1201 
1202 	        NGI_GET_M(item, m);
1203 		if ((m = ng_ppp_addproto(m, proto, 0)) == NULL) {
1204 			NG_FREE_ITEM(item);
1205 			return (ENOBUFS);
1206 		}
1207 		NGI_M(item) = m;
1208 
1209 		/* Send packet out hook. */
1210 		NG_FWD_ITEM_HOOK(error, item, priv->hooks[HOOK_INDEX_ENCRYPT]);
1211 		return (error);
1212 	}
1213 
1214 	return (ng_ppp_mp_xmit(node, item, proto));
1215 }
1216 
1217 /*
1218  * Receive data on a hook encrypt.
1219  */
1220 static int
1221 ng_ppp_rcvdata_encrypt(hook_p hook, item_p item)
1222 {
1223 	const node_p node = NG_HOOK_NODE(hook);
1224 	const priv_p priv = NG_NODE_PRIVATE(node);
1225 
1226 	if (!priv->conf.enableEncryption) {
1227 		NG_FREE_ITEM(item);
1228 		return (ENXIO);
1229 	}
1230 	return (ng_ppp_mp_xmit(node, item, PROT_CRYPTD));
1231 }
1232 
1233 static int
1234 ng_ppp_crypt_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
1235 {
1236 	const priv_p priv = NG_NODE_PRIVATE(node);
1237 
1238 	if (proto == PROT_CRYPTD) {
1239 		if (priv->conf.enableDecryption &&
1240 		    priv->hooks[HOOK_INDEX_DECRYPT] != NULL) {
1241 			int error;
1242 
1243 			/* Send packet out hook. */
1244 			NG_FWD_ITEM_HOOK(error, item,
1245 			    priv->hooks[HOOK_INDEX_DECRYPT]);
1246 			return (error);
1247 		} else {
1248 			/* Disabled protos MUST be silently discarded, but
1249 			 * unsupported MUST not. Let user-level decide this. */
1250 			return (ng_ppp_bypass(node, item, proto, linkNum));
1251 		}
1252 	}
1253 
1254 	return (ng_ppp_comp_recv(node, item, proto, linkNum));
1255 }
1256 
1257 /*
1258  * Receive data on a hook decrypt.
1259  */
1260 static int
1261 ng_ppp_rcvdata_decrypt(hook_p hook, item_p item)
1262 {
1263 	const node_p node = NG_HOOK_NODE(hook);
1264 	const priv_p priv = NG_NODE_PRIVATE(node);
1265 	uint16_t proto;
1266 	struct mbuf *m;
1267 
1268 	if (!priv->conf.enableDecryption) {
1269 		NG_FREE_ITEM(item);
1270 		return (ENXIO);
1271 	}
1272 	NGI_GET_M(item, m);
1273 	if ((m = ng_ppp_cutproto(m, &proto)) == NULL) {
1274 	        NG_FREE_ITEM(item);
1275 	        return (EIO);
1276 	}
1277 	NGI_M(item) = m;
1278 	if (!PROT_VALID(proto)) {
1279 		priv->bundleStats.badProtos++;
1280 		NG_FREE_ITEM(item);
1281 		return (EIO);
1282 	}
1283 	return (ng_ppp_comp_recv(node, item, proto, NG_PPP_BUNDLE_LINKNUM));
1284 }
1285 
1286 /*
1287  * Link layer
1288  */
1289 
1290 static int
1291 ng_ppp_link_xmit(node_p node, item_p item, uint16_t proto, uint16_t linkNum, int plen)
1292 {
1293 	const priv_p priv = NG_NODE_PRIVATE(node);
1294 	struct ng_ppp_link *link;
1295 	int len, error;
1296 	struct mbuf *m;
1297 	uint16_t mru;
1298 
1299 	/* Check if link correct. */
1300 	if (linkNum >= NG_PPP_MAX_LINKS) {
1301 		ERROUT(ENETDOWN);
1302 	}
1303 
1304 	/* Get link pointer (optimization). */
1305 	link = &priv->links[linkNum];
1306 
1307 	/* Check link status (if real). */
1308 	if (link->hook == NULL) {
1309 		ERROUT(ENETDOWN);
1310 	}
1311 
1312 	/* Extract mbuf. */
1313 	NGI_GET_M(item, m);
1314 
1315 	/* Check peer's MRU for this link. */
1316 	mru = link->conf.mru;
1317 	if (mru != 0 && m->m_pkthdr.len > mru) {
1318 		NG_FREE_M(m);
1319 		ERROUT(EMSGSIZE);
1320 	}
1321 
1322 	/* Prepend protocol number, possibly compressed. */
1323 	if ((m = ng_ppp_addproto(m, proto, link->conf.enableProtoComp)) ==
1324 	    NULL) {
1325 		ERROUT(ENOBUFS);
1326 	}
1327 
1328 	/* Prepend address and control field (unless compressed). */
1329 	if (proto == PROT_LCP || !link->conf.enableACFComp) {
1330 		if ((m = ng_ppp_prepend(m, &ng_ppp_acf, 2)) == NULL)
1331 			ERROUT(ENOBUFS);
1332 	}
1333 
1334 	/* Deliver frame. */
1335 	len = m->m_pkthdr.len;
1336 	NG_FWD_NEW_DATA(error, item, link->hook, m);
1337 
1338 	mtx_lock(&priv->xmtx);
1339 
1340 	/* Update link stats. */
1341 	link->stats.xmitFrames++;
1342 	link->stats.xmitOctets += len;
1343 
1344 	/* Update bundle stats. */
1345 	if (plen > 0) {
1346 	    priv->bundleStats.xmitFrames++;
1347 	    priv->bundleStats.xmitOctets += plen;
1348 	}
1349 
1350 	/* Update 'bytes in queue' counter. */
1351 	if (error == 0) {
1352 		/* bytesInQueue and lastWrite required only for mp_strategy. */
1353 		if (priv->conf.enableMultilink && !priv->allLinksEqual &&
1354 		    !priv->conf.enableRoundRobin) {
1355 			/* If queue was empty, then mark this time. */
1356 			if (link->bytesInQueue == 0)
1357 				getmicrouptime(&link->lastWrite);
1358 			link->bytesInQueue += len + MP_AVERAGE_LINK_OVERHEAD;
1359 			/* Limit max queue length to 50 pkts. BW can be defined
1360 		    	   incorrectly and link may not signal overload. */
1361 			if (link->bytesInQueue > 50 * 1600)
1362 				link->bytesInQueue = 50 * 1600;
1363 		}
1364 	}
1365 	mtx_unlock(&priv->xmtx);
1366 	return (error);
1367 
1368 done:
1369 	NG_FREE_ITEM(item);
1370 	return (error);
1371 }
1372 
1373 /*
1374  * Receive data on a hook linkX.
1375  */
1376 static int
1377 ng_ppp_rcvdata(hook_p hook, item_p item)
1378 {
1379 	const node_p node = NG_HOOK_NODE(hook);
1380 	const priv_p priv = NG_NODE_PRIVATE(node);
1381 	const int index = (intptr_t)NG_HOOK_PRIVATE(hook);
1382 	const uint16_t linkNum = (uint16_t)~index;
1383 	struct ng_ppp_link * const link = &priv->links[linkNum];
1384 	uint16_t proto;
1385 	struct mbuf *m;
1386 	int error = 0;
1387 
1388 	KASSERT(linkNum < NG_PPP_MAX_LINKS,
1389 	    ("%s: bogus index 0x%x", __func__, index));
1390 
1391 	NGI_GET_M(item, m);
1392 
1393 	mtx_lock(&priv->rmtx);
1394 
1395 	/* Stats */
1396 	link->stats.recvFrames++;
1397 	link->stats.recvOctets += m->m_pkthdr.len;
1398 
1399 	/* Strip address and control fields, if present. */
1400 	if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
1401 		ERROUT(ENOBUFS);
1402 	if (mtod(m, uint8_t *)[0] == 0xff &&
1403 	    mtod(m, uint8_t *)[1] == 0x03)
1404 		m_adj(m, 2);
1405 
1406 	/* Get protocol number */
1407 	if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
1408 		ERROUT(ENOBUFS);
1409 	NGI_M(item) = m; 	/* Put changed m back into item. */
1410 
1411 	if (!PROT_VALID(proto)) {
1412 		link->stats.badProtos++;
1413 		ERROUT(EIO);
1414 	}
1415 
1416 	/* LCP packets must go directly to bypass. */
1417 	if (proto >= 0xB000) {
1418 		mtx_unlock(&priv->rmtx);
1419 		return (ng_ppp_bypass(node, item, proto, linkNum));
1420 	}
1421 
1422 	/* Other packets are denied on a disabled link. */
1423 	if (!link->conf.enableLink)
1424 		ERROUT(ENXIO);
1425 
1426 	/* Proceed to multilink layer. Mutex will be unlocked inside. */
1427 	error = ng_ppp_mp_recv(node, item, proto, linkNum);
1428 	mtx_assert(&priv->rmtx, MA_NOTOWNED);
1429 	return (error);
1430 
1431 done:
1432 	mtx_unlock(&priv->rmtx);
1433 	NG_FREE_ITEM(item);
1434 	return (error);
1435 }
1436 
1437 /*
1438  * Multilink layer
1439  */
1440 
1441 /*
1442  * Handle an incoming multi-link fragment
1443  *
1444  * The fragment reassembly algorithm is somewhat complex. This is mainly
1445  * because we are required not to reorder the reconstructed packets, yet
1446  * fragments are only guaranteed to arrive in order on a per-link basis.
1447  * In other words, when we have a complete packet ready, but the previous
1448  * packet is still incomplete, we have to decide between delivering the
1449  * complete packet and throwing away the incomplete one, or waiting to
1450  * see if the remainder of the incomplete one arrives, at which time we
1451  * can deliver both packets, in order.
1452  *
1453  * This problem is exacerbated by "sequence number slew", which is when
1454  * the sequence numbers coming in from different links are far apart from
1455  * each other. In particular, certain unnamed equipment (*cough* Ascend)
1456  * has been seen to generate sequence number slew of up to 10 on an ISDN
1457  * 2B-channel MP link. There is nothing invalid about sequence number slew
1458  * but it makes the reasssembly process have to work harder.
1459  *
1460  * However, the peer is required to transmit fragments in order on each
1461  * link. That means if we define MSEQ as the minimum over all links of
1462  * the highest sequence number received on that link, then we can always
1463  * give up any hope of receiving a fragment with sequence number < MSEQ in
1464  * the future (all of this using 'wraparound' sequence number space).
1465  * Therefore we can always immediately throw away incomplete packets
1466  * missing fragments with sequence numbers < MSEQ.
1467  *
1468  * Here is an overview of our algorithm:
1469  *
1470  *    o Received fragments are inserted into a queue, for which we
1471  *	maintain these invariants between calls to this function:
1472  *
1473  *	- Fragments are ordered in the queue by sequence number
1474  *	- If a complete packet is at the head of the queue, then
1475  *	  the first fragment in the packet has seq# > MSEQ + 1
1476  *	  (otherwise, we could deliver it immediately)
1477  *	- If any fragments have seq# < MSEQ, then they are necessarily
1478  *	  part of a packet whose missing seq#'s are all > MSEQ (otherwise,
1479  *	  we can throw them away because they'll never be completed)
1480  *	- The queue contains at most MP_MAX_QUEUE_LEN fragments
1481  *
1482  *    o We have a periodic timer that checks the queue for the first
1483  *	complete packet that has been sitting in the queue "too long".
1484  *	When one is detected, all previous (incomplete) fragments are
1485  *	discarded, their missing fragments are declared lost and MSEQ
1486  *	is increased.
1487  *
1488  *    o If we recieve a fragment with seq# < MSEQ, we throw it away
1489  *	because we've already delcared it lost.
1490  *
1491  * This assumes linkNum != NG_PPP_BUNDLE_LINKNUM.
1492  */
1493 static int
1494 ng_ppp_mp_recv(node_p node, item_p item, uint16_t proto, uint16_t linkNum)
1495 {
1496 	const priv_p priv = NG_NODE_PRIVATE(node);
1497 	struct ng_ppp_link *const link = &priv->links[linkNum];
1498 	struct ng_ppp_frag *frag;
1499 	struct ng_ppp_frag *qent;
1500 	int i, diff, inserted;
1501 	struct mbuf *m;
1502 	int	error = 0;
1503 
1504 	if ((!priv->conf.enableMultilink) || proto != PROT_MP) {
1505 		/* Stats */
1506 		priv->bundleStats.recvFrames++;
1507 		priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
1508 
1509 		mtx_unlock(&priv->rmtx);
1510 		return (ng_ppp_crypt_recv(node, item, proto, linkNum));
1511 	}
1512 
1513 	NGI_GET_M(item, m);
1514 
1515 	/* Get a new frag struct from the free queue */
1516 	if ((frag = TAILQ_FIRST(&priv->fragsfree)) == NULL) {
1517 		printf("No free fragments headers in ng_ppp!\n");
1518 		NG_FREE_M(m);
1519 		goto process;
1520 	}
1521 
1522 	/* Extract fragment information from MP header */
1523 	if (priv->conf.recvShortSeq) {
1524 		uint16_t shdr;
1525 
1526 		if (m->m_pkthdr.len < 2) {
1527 			link->stats.runts++;
1528 			NG_FREE_M(m);
1529 			ERROUT(EINVAL);
1530 		}
1531 		if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL)
1532 			ERROUT(ENOBUFS);
1533 
1534 		shdr = ntohs(*mtod(m, uint16_t *));
1535 		frag->seq = MP_SHORT_EXTEND(shdr);
1536 		frag->first = (shdr & MP_SHORT_FIRST_FLAG) != 0;
1537 		frag->last = (shdr & MP_SHORT_LAST_FLAG) != 0;
1538 		diff = MP_SHORT_SEQ_DIFF(frag->seq, priv->mseq);
1539 		m_adj(m, 2);
1540 	} else {
1541 		uint32_t lhdr;
1542 
1543 		if (m->m_pkthdr.len < 4) {
1544 			link->stats.runts++;
1545 			NG_FREE_M(m);
1546 			ERROUT(EINVAL);
1547 		}
1548 		if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL)
1549 			ERROUT(ENOBUFS);
1550 
1551 		lhdr = ntohl(*mtod(m, uint32_t *));
1552 		frag->seq = MP_LONG_EXTEND(lhdr);
1553 		frag->first = (lhdr & MP_LONG_FIRST_FLAG) != 0;
1554 		frag->last = (lhdr & MP_LONG_LAST_FLAG) != 0;
1555 		diff = MP_LONG_SEQ_DIFF(frag->seq, priv->mseq);
1556 		m_adj(m, 4);
1557 	}
1558 	frag->data = m;
1559 	getmicrouptime(&frag->timestamp);
1560 
1561 	/* If sequence number is < MSEQ, we've already declared this
1562 	   fragment as lost, so we have no choice now but to drop it */
1563 	if (diff < 0) {
1564 		link->stats.dropFragments++;
1565 		NG_FREE_M(m);
1566 		ERROUT(0);
1567 	}
1568 
1569 	/* Update highest received sequence number on this link and MSEQ */
1570 	priv->mseq = link->seq = frag->seq;
1571 	for (i = 0; i < priv->numActiveLinks; i++) {
1572 		struct ng_ppp_link *const alink =
1573 		    &priv->links[priv->activeLinks[i]];
1574 
1575 		if (MP_RECV_SEQ_DIFF(priv, alink->seq, priv->mseq) < 0)
1576 			priv->mseq = alink->seq;
1577 	}
1578 
1579 	/* Remove frag struct from free queue. */
1580 	TAILQ_REMOVE(&priv->fragsfree, frag, f_qent);
1581 
1582 	/* Add fragment to queue, which is sorted by sequence number */
1583 	inserted = 0;
1584 	TAILQ_FOREACH_REVERSE(qent, &priv->frags, ng_ppp_fraglist, f_qent) {
1585 		diff = MP_RECV_SEQ_DIFF(priv, frag->seq, qent->seq);
1586 		if (diff > 0) {
1587 			TAILQ_INSERT_AFTER(&priv->frags, qent, frag, f_qent);
1588 			inserted = 1;
1589 			break;
1590 		} else if (diff == 0) {	     /* should never happen! */
1591 			link->stats.dupFragments++;
1592 			NG_FREE_M(frag->data);
1593 			TAILQ_INSERT_HEAD(&priv->fragsfree, frag, f_qent);
1594 			ERROUT(EINVAL);
1595 		}
1596 	}
1597 	if (!inserted)
1598 		TAILQ_INSERT_HEAD(&priv->frags, frag, f_qent);
1599 
1600 process:
1601 	/* Process the queue */
1602 	/* NOTE: rmtx will be unlocked for sending time! */
1603 	error = ng_ppp_frag_process(node, item);
1604 	mtx_unlock(&priv->rmtx);
1605 	return (error);
1606 
1607 done:
1608 	mtx_unlock(&priv->rmtx);
1609 	NG_FREE_ITEM(item);
1610 	return (error);
1611 }
1612 
1613 /************************************************************************
1614 			HELPER STUFF
1615  ************************************************************************/
1616 
1617 /*
1618  * If new mseq > current then set it and update all active links
1619  */
1620 static void
1621 ng_ppp_bump_mseq(node_p node, int32_t new_mseq)
1622 {
1623 	const priv_p priv = NG_NODE_PRIVATE(node);
1624 	int i;
1625 
1626 	if (MP_RECV_SEQ_DIFF(priv, priv->mseq, new_mseq) < 0) {
1627 		priv->mseq = new_mseq;
1628 		for (i = 0; i < priv->numActiveLinks; i++) {
1629 			struct ng_ppp_link *const alink =
1630 			    &priv->links[priv->activeLinks[i]];
1631 
1632 			if (MP_RECV_SEQ_DIFF(priv,
1633 			    alink->seq, new_mseq) < 0)
1634 				alink->seq = new_mseq;
1635 		}
1636 	}
1637 }
1638 
1639 /*
1640  * Examine our list of fragments, and determine if there is a
1641  * complete and deliverable packet at the head of the list.
1642  * Return 1 if so, zero otherwise.
1643  */
1644 static int
1645 ng_ppp_check_packet(node_p node)
1646 {
1647 	const priv_p priv = NG_NODE_PRIVATE(node);
1648 	struct ng_ppp_frag *qent, *qnext;
1649 
1650 	/* Check for empty queue */
1651 	if (TAILQ_EMPTY(&priv->frags))
1652 		return (0);
1653 
1654 	/* Check first fragment is the start of a deliverable packet */
1655 	qent = TAILQ_FIRST(&priv->frags);
1656 	if (!qent->first || MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) > 1)
1657 		return (0);
1658 
1659 	/* Check that all the fragments are there */
1660 	while (!qent->last) {
1661 		qnext = TAILQ_NEXT(qent, f_qent);
1662 		if (qnext == NULL)	/* end of queue */
1663 			return (0);
1664 		if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq))
1665 			return (0);
1666 		qent = qnext;
1667 	}
1668 
1669 	/* Got one */
1670 	return (1);
1671 }
1672 
1673 /*
1674  * Pull a completed packet off the head of the incoming fragment queue.
1675  * This assumes there is a completed packet there to pull off.
1676  */
1677 static void
1678 ng_ppp_get_packet(node_p node, struct mbuf **mp)
1679 {
1680 	const priv_p priv = NG_NODE_PRIVATE(node);
1681 	struct ng_ppp_frag *qent, *qnext;
1682 	struct mbuf *m = NULL, *tail;
1683 
1684 	qent = TAILQ_FIRST(&priv->frags);
1685 	KASSERT(!TAILQ_EMPTY(&priv->frags) && qent->first,
1686 	    ("%s: no packet", __func__));
1687 	for (tail = NULL; qent != NULL; qent = qnext) {
1688 		qnext = TAILQ_NEXT(qent, f_qent);
1689 		KASSERT(!TAILQ_EMPTY(&priv->frags),
1690 		    ("%s: empty q", __func__));
1691 		TAILQ_REMOVE(&priv->frags, qent, f_qent);
1692 		if (tail == NULL)
1693 			tail = m = qent->data;
1694 		else {
1695 			m->m_pkthdr.len += qent->data->m_pkthdr.len;
1696 			tail->m_next = qent->data;
1697 		}
1698 		while (tail->m_next != NULL)
1699 			tail = tail->m_next;
1700 		if (qent->last) {
1701 			qnext = NULL;
1702 			/* Bump MSEQ if necessary */
1703 			ng_ppp_bump_mseq(node, qent->seq);
1704 		}
1705 		TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
1706 	}
1707 	*mp = m;
1708 }
1709 
1710 /*
1711  * Trim fragments from the queue whose packets can never be completed.
1712  * This assumes a complete packet is NOT at the beginning of the queue.
1713  * Returns 1 if fragments were removed, zero otherwise.
1714  */
1715 static int
1716 ng_ppp_frag_trim(node_p node)
1717 {
1718 	const priv_p priv = NG_NODE_PRIVATE(node);
1719 	struct ng_ppp_frag *qent, *qnext = NULL;
1720 	int removed = 0;
1721 
1722 	/* Scan for "dead" fragments and remove them */
1723 	while (1) {
1724 		int dead = 0;
1725 
1726 		/* If queue is empty, we're done */
1727 		if (TAILQ_EMPTY(&priv->frags))
1728 			break;
1729 
1730 		/* Determine whether first fragment can ever be completed */
1731 		TAILQ_FOREACH(qent, &priv->frags, f_qent) {
1732 			if (MP_RECV_SEQ_DIFF(priv, qent->seq, priv->mseq) >= 0)
1733 				break;
1734 			qnext = TAILQ_NEXT(qent, f_qent);
1735 			KASSERT(qnext != NULL,
1736 			    ("%s: last frag < MSEQ?", __func__));
1737 			if (qnext->seq != MP_NEXT_RECV_SEQ(priv, qent->seq)
1738 			    || qent->last || qnext->first) {
1739 				dead = 1;
1740 				break;
1741 			}
1742 		}
1743 		if (!dead)
1744 			break;
1745 
1746 		/* Remove fragment and all others in the same packet */
1747 		while ((qent = TAILQ_FIRST(&priv->frags)) != qnext) {
1748 			KASSERT(!TAILQ_EMPTY(&priv->frags),
1749 			    ("%s: empty q", __func__));
1750 			priv->bundleStats.dropFragments++;
1751 			TAILQ_REMOVE(&priv->frags, qent, f_qent);
1752 			NG_FREE_M(qent->data);
1753 			TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
1754 			removed = 1;
1755 		}
1756 	}
1757 	return (removed);
1758 }
1759 
1760 /*
1761  * Drop fragments on queue overflow.
1762  * Returns 1 if fragments were removed, zero otherwise.
1763  */
1764 static int
1765 ng_ppp_frag_drop(node_p node)
1766 {
1767 	const priv_p priv = NG_NODE_PRIVATE(node);
1768 
1769 	/* Check queue length */
1770 	if (TAILQ_EMPTY(&priv->fragsfree)) {
1771 		struct ng_ppp_frag *qent;
1772 
1773 		/* Get oldest fragment */
1774 		KASSERT(!TAILQ_EMPTY(&priv->frags),
1775 		    ("%s: empty q", __func__));
1776 		qent = TAILQ_FIRST(&priv->frags);
1777 
1778 		/* Bump MSEQ if necessary */
1779 		ng_ppp_bump_mseq(node, qent->seq);
1780 
1781 		/* Drop it */
1782 		priv->bundleStats.dropFragments++;
1783 		TAILQ_REMOVE(&priv->frags, qent, f_qent);
1784 		NG_FREE_M(qent->data);
1785 		TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
1786 
1787 		return (1);
1788 	}
1789 	return (0);
1790 }
1791 
1792 /*
1793  * Run the queue, restoring the queue invariants
1794  */
1795 static int
1796 ng_ppp_frag_process(node_p node, item_p oitem)
1797 {
1798 	const priv_p priv = NG_NODE_PRIVATE(node);
1799 	struct mbuf *m;
1800 	item_p item;
1801 	uint16_t proto;
1802 
1803 	do {
1804 		/* Deliver any deliverable packets */
1805 		while (ng_ppp_check_packet(node)) {
1806 			ng_ppp_get_packet(node, &m);
1807 			if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
1808 				continue;
1809 			if (!PROT_VALID(proto)) {
1810 				priv->bundleStats.badProtos++;
1811 				NG_FREE_M(m);
1812 				continue;
1813 			}
1814 			if (oitem) { /* If original item present - reuse it. */
1815 				item = oitem;
1816 				oitem = NULL;
1817 				NGI_M(item) = m;
1818 			} else {
1819 				item = ng_package_data(m, NG_NOFLAGS);
1820 			}
1821 			if (item != NULL) {
1822 				/* Stats */
1823 				priv->bundleStats.recvFrames++;
1824 				priv->bundleStats.recvOctets +=
1825 				    NGI_M(item)->m_pkthdr.len;
1826 
1827 				/* Drop mutex for the sending time.
1828 				 * Priv may change, but we are ready!
1829 				 */
1830 				mtx_unlock(&priv->rmtx);
1831 				ng_ppp_crypt_recv(node, item, proto,
1832 					NG_PPP_BUNDLE_LINKNUM);
1833 				mtx_lock(&priv->rmtx);
1834 			}
1835 		}
1836 	  /* Delete dead fragments and try again */
1837 	} while (ng_ppp_frag_trim(node) || ng_ppp_frag_drop(node));
1838 
1839 	/* If we haven't reused original item - free it. */
1840 	if (oitem) NG_FREE_ITEM(oitem);
1841 
1842 	/* Done */
1843 	return (0);
1844 }
1845 
1846 /*
1847  * Check for 'stale' completed packets that need to be delivered
1848  *
1849  * If a link goes down or has a temporary failure, MSEQ can get
1850  * "stuck", because no new incoming fragments appear on that link.
1851  * This can cause completed packets to never get delivered if
1852  * their sequence numbers are all > MSEQ + 1.
1853  *
1854  * This routine checks how long all of the completed packets have
1855  * been sitting in the queue, and if too long, removes fragments
1856  * from the queue and increments MSEQ to allow them to be delivered.
1857  */
1858 static void
1859 ng_ppp_frag_checkstale(node_p node)
1860 {
1861 	const priv_p priv = NG_NODE_PRIVATE(node);
1862 	struct ng_ppp_frag *qent, *beg, *end;
1863 	struct timeval now, age;
1864 	struct mbuf *m;
1865 	int seq;
1866 	item_p item;
1867 	int endseq;
1868 	uint16_t proto;
1869 
1870 	now.tv_sec = 0;			/* uninitialized state */
1871 	while (1) {
1872 
1873 		/* If queue is empty, we're done */
1874 		if (TAILQ_EMPTY(&priv->frags))
1875 			break;
1876 
1877 		/* Find the first complete packet in the queue */
1878 		beg = end = NULL;
1879 		seq = TAILQ_FIRST(&priv->frags)->seq;
1880 		TAILQ_FOREACH(qent, &priv->frags, f_qent) {
1881 			if (qent->first)
1882 				beg = qent;
1883 			else if (qent->seq != seq)
1884 				beg = NULL;
1885 			if (beg != NULL && qent->last) {
1886 				end = qent;
1887 				break;
1888 			}
1889 			seq = MP_NEXT_RECV_SEQ(priv, seq);
1890 		}
1891 
1892 		/* If none found, exit */
1893 		if (end == NULL)
1894 			break;
1895 
1896 		/* Get current time (we assume we've been up for >= 1 second) */
1897 		if (now.tv_sec == 0)
1898 			getmicrouptime(&now);
1899 
1900 		/* Check if packet has been queued too long */
1901 		age = now;
1902 		timevalsub(&age, &beg->timestamp);
1903 		if (timevalcmp(&age, &ng_ppp_max_staleness, < ))
1904 			break;
1905 
1906 		/* Throw away junk fragments in front of the completed packet */
1907 		while ((qent = TAILQ_FIRST(&priv->frags)) != beg) {
1908 			KASSERT(!TAILQ_EMPTY(&priv->frags),
1909 			    ("%s: empty q", __func__));
1910 			priv->bundleStats.dropFragments++;
1911 			TAILQ_REMOVE(&priv->frags, qent, f_qent);
1912 			NG_FREE_M(qent->data);
1913 			TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
1914 		}
1915 
1916 		/* Extract completed packet */
1917 		endseq = end->seq;
1918 		ng_ppp_get_packet(node, &m);
1919 
1920 		if ((m = ng_ppp_cutproto(m, &proto)) == NULL)
1921 			continue;
1922 		if (!PROT_VALID(proto)) {
1923 			priv->bundleStats.badProtos++;
1924 			NG_FREE_M(m);
1925 			continue;
1926 		}
1927 
1928 		/* Deliver packet */
1929 		if ((item = ng_package_data(m, NG_NOFLAGS)) != NULL) {
1930 			/* Stats */
1931 			priv->bundleStats.recvFrames++;
1932 			priv->bundleStats.recvOctets += NGI_M(item)->m_pkthdr.len;
1933 
1934 			ng_ppp_crypt_recv(node, item, proto,
1935 				NG_PPP_BUNDLE_LINKNUM);
1936 		}
1937 	}
1938 }
1939 
1940 /*
1941  * Periodically call ng_ppp_frag_checkstale()
1942  */
1943 static void
1944 ng_ppp_frag_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1945 {
1946 	/* XXX: is this needed? */
1947 	if (NG_NODE_NOT_VALID(node))
1948 		return;
1949 
1950 	/* Scan the fragment queue */
1951 	ng_ppp_frag_checkstale(node);
1952 
1953 	/* Start timer again */
1954 	ng_ppp_start_frag_timer(node);
1955 }
1956 
1957 /*
1958  * Deliver a frame out on the bundle, i.e., figure out how to fragment
1959  * the frame across the individual PPP links and do so.
1960  */
1961 static int
1962 ng_ppp_mp_xmit(node_p node, item_p item, uint16_t proto)
1963 {
1964 	const priv_p priv = NG_NODE_PRIVATE(node);
1965 	const int hdr_len = priv->conf.xmitShortSeq ? 2 : 4;
1966 	int distrib[NG_PPP_MAX_LINKS];
1967 	int firstFragment;
1968 	int activeLinkNum;
1969 	struct mbuf *m;
1970 	int	plen;
1971 	int	frags;
1972 	int32_t	seq;
1973 
1974 	/* At least one link must be active */
1975 	if (priv->numActiveLinks == 0) {
1976 		NG_FREE_ITEM(item);
1977 		return (ENETDOWN);
1978 	}
1979 
1980 	/* Save length for later stats. */
1981 	plen = NGI_M(item)->m_pkthdr.len;
1982 
1983 	if (!priv->conf.enableMultilink) {
1984 		return (ng_ppp_link_xmit(node, item, proto,
1985 		    priv->activeLinks[0], plen));
1986 	}
1987 
1988 	/* Extract mbuf. */
1989 	NGI_GET_M(item, m);
1990 
1991 	/* Prepend protocol number, possibly compressed. */
1992 	if ((m = ng_ppp_addproto(m, proto, 1)) == NULL) {
1993 		NG_FREE_ITEM(item);
1994 		return (ENOBUFS);
1995 	}
1996 
1997 	/* Clear distribution plan */
1998 	bzero(&distrib, priv->numActiveLinks * sizeof(distrib[0]));
1999 
2000 	mtx_lock(&priv->xmtx);
2001 
2002 	/* Round-robin strategy */
2003 	if (priv->conf.enableRoundRobin) {
2004 		activeLinkNum = priv->lastLink++ % priv->numActiveLinks;
2005 		distrib[activeLinkNum] = m->m_pkthdr.len;
2006 		goto deliver;
2007 	}
2008 
2009 	/* Strategy when all links are equivalent (optimize the common case) */
2010 	if (priv->allLinksEqual) {
2011 		int	numFrags, fraction, remain;
2012 		int	i;
2013 
2014 		/* Calculate optimal fragment count */
2015 		numFrags = priv->numActiveLinks;
2016 		if (numFrags > m->m_pkthdr.len / MP_MIN_FRAG_LEN)
2017 		    numFrags = m->m_pkthdr.len / MP_MIN_FRAG_LEN;
2018 		if (numFrags == 0)
2019 		    numFrags = 1;
2020 
2021 		fraction = m->m_pkthdr.len / numFrags;
2022 		remain = m->m_pkthdr.len - (fraction * numFrags);
2023 
2024 		/* Assign distribution */
2025 		for (i = 0; i < numFrags; i++) {
2026 			distrib[priv->lastLink++ % priv->numActiveLinks]
2027 			    = fraction + (((remain--) > 0)?1:0);
2028 		}
2029 		goto deliver;
2030 	}
2031 
2032 	/* Strategy when all links are not equivalent */
2033 	ng_ppp_mp_strategy(node, m->m_pkthdr.len, distrib);
2034 
2035 deliver:
2036 	/* Estimate fragments count */
2037 	frags = 0;
2038 	for (activeLinkNum = priv->numActiveLinks - 1;
2039 	    activeLinkNum >= 0; activeLinkNum--) {
2040 		const uint16_t linkNum = priv->activeLinks[activeLinkNum];
2041 		struct ng_ppp_link *const link = &priv->links[linkNum];
2042 
2043 		frags += (distrib[activeLinkNum] + link->conf.mru - hdr_len - 1) /
2044 		    (link->conf.mru - hdr_len);
2045 	}
2046 
2047 	/* Get out initial sequence number */
2048 	seq = priv->xseq;
2049 
2050 	/* Update next sequence number */
2051 	if (priv->conf.xmitShortSeq) {
2052 	    priv->xseq = (seq + frags) & MP_SHORT_SEQ_MASK;
2053 	} else {
2054 	    priv->xseq = (seq + frags) & MP_LONG_SEQ_MASK;
2055 	}
2056 
2057 	mtx_unlock(&priv->xmtx);
2058 
2059 	/* Send alloted portions of frame out on the link(s) */
2060 	for (firstFragment = 1, activeLinkNum = priv->numActiveLinks - 1;
2061 	    activeLinkNum >= 0; activeLinkNum--) {
2062 		const uint16_t linkNum = priv->activeLinks[activeLinkNum];
2063 		struct ng_ppp_link *const link = &priv->links[linkNum];
2064 
2065 		/* Deliver fragment(s) out the next link */
2066 		for ( ; distrib[activeLinkNum] > 0; firstFragment = 0) {
2067 			int len, lastFragment, error;
2068 			struct mbuf *m2;
2069 
2070 			/* Calculate fragment length; don't exceed link MTU */
2071 			len = distrib[activeLinkNum];
2072 			if (len > link->conf.mru - hdr_len)
2073 				len = link->conf.mru - hdr_len;
2074 			distrib[activeLinkNum] -= len;
2075 			lastFragment = (len == m->m_pkthdr.len);
2076 
2077 			/* Split off next fragment as "m2" */
2078 			m2 = m;
2079 			if (!lastFragment) {
2080 				struct mbuf *n = m_split(m, len, M_DONTWAIT);
2081 
2082 				if (n == NULL) {
2083 					NG_FREE_M(m);
2084 					if (firstFragment)
2085 						NG_FREE_ITEM(item);
2086 					return (ENOMEM);
2087 				}
2088 				m_tag_copy_chain(n, m, M_DONTWAIT);
2089 				m = n;
2090 			}
2091 
2092 			/* Prepend MP header */
2093 			if (priv->conf.xmitShortSeq) {
2094 				uint16_t shdr;
2095 
2096 				shdr = seq;
2097 				seq = (seq + 1) & MP_SHORT_SEQ_MASK;
2098 				if (firstFragment)
2099 					shdr |= MP_SHORT_FIRST_FLAG;
2100 				if (lastFragment)
2101 					shdr |= MP_SHORT_LAST_FLAG;
2102 				shdr = htons(shdr);
2103 				m2 = ng_ppp_prepend(m2, &shdr, 2);
2104 			} else {
2105 				uint32_t lhdr;
2106 
2107 				lhdr = seq;
2108 				seq = (seq + 1) & MP_LONG_SEQ_MASK;
2109 				if (firstFragment)
2110 					lhdr |= MP_LONG_FIRST_FLAG;
2111 				if (lastFragment)
2112 					lhdr |= MP_LONG_LAST_FLAG;
2113 				lhdr = htonl(lhdr);
2114 				m2 = ng_ppp_prepend(m2, &lhdr, 4);
2115 			}
2116 			if (m2 == NULL) {
2117 				if (!lastFragment)
2118 					m_freem(m);
2119 				if (firstFragment)
2120 					NG_FREE_ITEM(item);
2121 				return (ENOBUFS);
2122 			}
2123 
2124 			/* Send fragment */
2125 			if (firstFragment) {
2126 				NGI_M(item) = m2; /* Reuse original item. */
2127 			} else {
2128 				item = ng_package_data(m2, NG_NOFLAGS);
2129 			}
2130 			if (item != NULL) {
2131 				error = ng_ppp_link_xmit(node, item, PROT_MP,
2132 					    linkNum, (firstFragment?plen:0));
2133 				if (error != 0) {
2134 					if (!lastFragment)
2135 						NG_FREE_M(m);
2136 					return (error);
2137 				}
2138 			}
2139 		}
2140 	}
2141 
2142 	/* Done */
2143 	return (0);
2144 }
2145 
2146 /*
2147  * Computing the optimal fragmentation
2148  * -----------------------------------
2149  *
2150  * This routine tries to compute the optimal fragmentation pattern based
2151  * on each link's latency, bandwidth, and calculated additional latency.
2152  * The latter quantity is the additional latency caused by previously
2153  * written data that has not been transmitted yet.
2154  *
2155  * This algorithm is only useful when not all of the links have the
2156  * same latency and bandwidth values.
2157  *
2158  * The essential idea is to make the last bit of each fragment of the
2159  * frame arrive at the opposite end at the exact same time. This greedy
2160  * algorithm is optimal, in that no other scheduling could result in any
2161  * packet arriving any sooner unless packets are delivered out of order.
2162  *
2163  * Suppose link i has bandwidth b_i (in tens of bytes per milisecond) and
2164  * latency l_i (in miliseconds). Consider the function function f_i(t)
2165  * which is equal to the number of bytes that will have arrived at
2166  * the peer after t miliseconds if we start writing continuously at
2167  * time t = 0. Then f_i(t) = b_i * (t - l_i) = ((b_i * t) - (l_i * b_i).
2168  * That is, f_i(t) is a line with slope b_i and y-intersect -(l_i * b_i).
2169  * Note that the y-intersect is always <= zero because latency can't be
2170  * negative.  Note also that really the function is f_i(t) except when
2171  * f_i(t) is negative, in which case the function is zero.  To take
2172  * care of this, let Q_i(t) = { if (f_i(t) > 0) return 1; else return 0; }.
2173  * So the actual number of bytes that will have arrived at the peer after
2174  * t miliseconds is f_i(t) * Q_i(t).
2175  *
2176  * At any given time, each link has some additional latency a_i >= 0
2177  * due to previously written fragment(s) which are still in the queue.
2178  * This value is easily computed from the time since last transmission,
2179  * the previous latency value, the number of bytes written, and the
2180  * link's bandwidth.
2181  *
2182  * Assume that l_i includes any a_i already, and that the links are
2183  * sorted by latency, so that l_i <= l_{i+1}.
2184  *
2185  * Let N be the total number of bytes in the current frame we are sending.
2186  *
2187  * Suppose we were to start writing bytes at time t = 0 on all links
2188  * simultaneously, which is the most we can possibly do.  Then let
2189  * F(t) be equal to the total number of bytes received by the peer
2190  * after t miliseconds. Then F(t) = Sum_i (f_i(t) * Q_i(t)).
2191  *
2192  * Our goal is simply this: fragment the frame across the links such
2193  * that the peer is able to reconstruct the completed frame as soon as
2194  * possible, i.e., at the least possible value of t. Call this value t_0.
2195  *
2196  * Then it follows that F(t_0) = N. Our strategy is first to find the value
2197  * of t_0, and then deduce how many bytes to write to each link.
2198  *
2199  * Rewriting F(t_0):
2200  *
2201  *   t_0 = ( N + Sum_i ( l_i * b_i * Q_i(t_0) ) ) / Sum_i ( b_i * Q_i(t_0) )
2202  *
2203  * Now, we note that Q_i(t) is constant for l_i <= t <= l_{i+1}. t_0 will
2204  * lie in one of these ranges.  To find it, we just need to find the i such
2205  * that F(l_i) <= N <= F(l_{i+1}).  Then we compute all the constant values
2206  * for Q_i() in this range, plug in the remaining values, solving for t_0.
2207  *
2208  * Once t_0 is known, then the number of bytes to send on link i is
2209  * just f_i(t_0) * Q_i(t_0).
2210  *
2211  * In other words, we start allocating bytes to the links one at a time.
2212  * We keep adding links until the frame is completely sent.  Some links
2213  * may not get any bytes because their latency is too high.
2214  *
2215  * Is all this work really worth the trouble?  Depends on the situation.
2216  * The bigger the ratio of computer speed to link speed, and the more
2217  * important total bundle latency is (e.g., for interactive response time),
2218  * the more it's worth it.  There is however the cost of calling this
2219  * function for every frame.  The running time is O(n^2) where n is the
2220  * number of links that receive a non-zero number of bytes.
2221  *
2222  * Since latency is measured in miliseconds, the "resolution" of this
2223  * algorithm is one milisecond.
2224  *
2225  * To avoid this algorithm altogether, configure all links to have the
2226  * same latency and bandwidth.
2227  */
2228 static void
2229 ng_ppp_mp_strategy(node_p node, int len, int *distrib)
2230 {
2231 	const priv_p priv = NG_NODE_PRIVATE(node);
2232 	int latency[NG_PPP_MAX_LINKS];
2233 	int sortByLatency[NG_PPP_MAX_LINKS];
2234 	int activeLinkNum;
2235 	int t0, total, topSum, botSum;
2236 	struct timeval now;
2237 	int i, numFragments;
2238 
2239 	/* If only one link, this gets real easy */
2240 	if (priv->numActiveLinks == 1) {
2241 		distrib[0] = len;
2242 		return;
2243 	}
2244 
2245 	/* Get current time */
2246 	getmicrouptime(&now);
2247 
2248 	/* Compute latencies for each link at this point in time */
2249 	for (activeLinkNum = 0;
2250 	    activeLinkNum < priv->numActiveLinks; activeLinkNum++) {
2251 		struct ng_ppp_link *alink;
2252 		struct timeval diff;
2253 		int xmitBytes;
2254 
2255 		/* Start with base latency value */
2256 		alink = &priv->links[priv->activeLinks[activeLinkNum]];
2257 		latency[activeLinkNum] = alink->latency;
2258 		sortByLatency[activeLinkNum] = activeLinkNum;	/* see below */
2259 
2260 		/* Any additional latency? */
2261 		if (alink->bytesInQueue == 0)
2262 			continue;
2263 
2264 		/* Compute time delta since last write */
2265 		diff = now;
2266 		timevalsub(&diff, &alink->lastWrite);
2267 
2268 		/* alink->bytesInQueue will be changed, mark change time. */
2269 		alink->lastWrite = now;
2270 
2271 		if (now.tv_sec < 0 || diff.tv_sec >= 10) {	/* sanity */
2272 			alink->bytesInQueue = 0;
2273 			continue;
2274 		}
2275 
2276 		/* How many bytes could have transmitted since last write? */
2277 		xmitBytes = (alink->conf.bandwidth * 10 * diff.tv_sec)
2278 		    + (alink->conf.bandwidth * (diff.tv_usec / 1000)) / 100;
2279 		alink->bytesInQueue -= xmitBytes;
2280 		if (alink->bytesInQueue < 0)
2281 			alink->bytesInQueue = 0;
2282 		else
2283 			latency[activeLinkNum] +=
2284 			    (100 * alink->bytesInQueue) / alink->conf.bandwidth;
2285 	}
2286 
2287 	/* Sort active links by latency */
2288 	qsort_r(sortByLatency,
2289 	    priv->numActiveLinks, sizeof(*sortByLatency), latency, ng_ppp_intcmp);
2290 
2291 	/* Find the interval we need (add links in sortByLatency[] order) */
2292 	for (numFragments = 1;
2293 	    numFragments < priv->numActiveLinks; numFragments++) {
2294 		for (total = i = 0; i < numFragments; i++) {
2295 			int flowTime;
2296 
2297 			flowTime = latency[sortByLatency[numFragments]]
2298 			    - latency[sortByLatency[i]];
2299 			total += ((flowTime * priv->links[
2300 			    priv->activeLinks[sortByLatency[i]]].conf.bandwidth)
2301 			    	+ 99) / 100;
2302 		}
2303 		if (total >= len)
2304 			break;
2305 	}
2306 
2307 	/* Solve for t_0 in that interval */
2308 	for (topSum = botSum = i = 0; i < numFragments; i++) {
2309 		int bw = priv->links[
2310 		    priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
2311 
2312 		topSum += latency[sortByLatency[i]] * bw;	/* / 100 */
2313 		botSum += bw;					/* / 100 */
2314 	}
2315 	t0 = ((len * 100) + topSum + botSum / 2) / botSum;
2316 
2317 	/* Compute f_i(t_0) all i */
2318 	for (total = i = 0; i < numFragments; i++) {
2319 		int bw = priv->links[
2320 		    priv->activeLinks[sortByLatency[i]]].conf.bandwidth;
2321 
2322 		distrib[sortByLatency[i]] =
2323 		    (bw * (t0 - latency[sortByLatency[i]]) + 50) / 100;
2324 		total += distrib[sortByLatency[i]];
2325 	}
2326 
2327 	/* Deal with any rounding error */
2328 	if (total < len) {
2329 		struct ng_ppp_link *fastLink =
2330 		    &priv->links[priv->activeLinks[sortByLatency[0]]];
2331 		int fast = 0;
2332 
2333 		/* Find the fastest link */
2334 		for (i = 1; i < numFragments; i++) {
2335 			struct ng_ppp_link *const link =
2336 			    &priv->links[priv->activeLinks[sortByLatency[i]]];
2337 
2338 			if (link->conf.bandwidth > fastLink->conf.bandwidth) {
2339 				fast = i;
2340 				fastLink = link;
2341 			}
2342 		}
2343 		distrib[sortByLatency[fast]] += len - total;
2344 	} else while (total > len) {
2345 		struct ng_ppp_link *slowLink =
2346 		    &priv->links[priv->activeLinks[sortByLatency[0]]];
2347 		int delta, slow = 0;
2348 
2349 		/* Find the slowest link that still has bytes to remove */
2350 		for (i = 1; i < numFragments; i++) {
2351 			struct ng_ppp_link *const link =
2352 			    &priv->links[priv->activeLinks[sortByLatency[i]]];
2353 
2354 			if (distrib[sortByLatency[slow]] == 0
2355 			  || (distrib[sortByLatency[i]] > 0
2356 			    && link->conf.bandwidth <
2357 			      slowLink->conf.bandwidth)) {
2358 				slow = i;
2359 				slowLink = link;
2360 			}
2361 		}
2362 		delta = total - len;
2363 		if (delta > distrib[sortByLatency[slow]])
2364 			delta = distrib[sortByLatency[slow]];
2365 		distrib[sortByLatency[slow]] -= delta;
2366 		total -= delta;
2367 	}
2368 }
2369 
2370 /*
2371  * Compare two integers
2372  */
2373 static int
2374 ng_ppp_intcmp(void *latency, const void *v1, const void *v2)
2375 {
2376 	const int index1 = *((const int *) v1);
2377 	const int index2 = *((const int *) v2);
2378 
2379 	return ((int *)latency)[index1] - ((int *)latency)[index2];
2380 }
2381 
2382 /*
2383  * Prepend a possibly compressed PPP protocol number in front of a frame
2384  */
2385 static struct mbuf *
2386 ng_ppp_addproto(struct mbuf *m, uint16_t proto, int compOK)
2387 {
2388 	if (compOK && PROT_COMPRESSABLE(proto)) {
2389 		uint8_t pbyte = (uint8_t)proto;
2390 
2391 		return ng_ppp_prepend(m, &pbyte, 1);
2392 	} else {
2393 		uint16_t pword = htons((uint16_t)proto);
2394 
2395 		return ng_ppp_prepend(m, &pword, 2);
2396 	}
2397 }
2398 
2399 /*
2400  * Cut a possibly compressed PPP protocol number from the front of a frame.
2401  */
2402 static struct mbuf *
2403 ng_ppp_cutproto(struct mbuf *m, uint16_t *proto)
2404 {
2405 
2406 	*proto = 0;
2407 	if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
2408 		return (NULL);
2409 
2410 	*proto = *mtod(m, uint8_t *);
2411 	m_adj(m, 1);
2412 
2413 	if (!PROT_VALID(*proto)) {
2414 		if (m->m_len < 1 && (m = m_pullup(m, 1)) == NULL)
2415 			return (NULL);
2416 
2417 		*proto = (*proto << 8) + *mtod(m, uint8_t *);
2418 		m_adj(m, 1);
2419 	}
2420 
2421 	return (m);
2422 }
2423 
2424 /*
2425  * Prepend some bytes to an mbuf.
2426  */
2427 static struct mbuf *
2428 ng_ppp_prepend(struct mbuf *m, const void *buf, int len)
2429 {
2430 	M_PREPEND(m, len, M_DONTWAIT);
2431 	if (m == NULL || (m->m_len < len && (m = m_pullup(m, len)) == NULL))
2432 		return (NULL);
2433 	bcopy(buf, mtod(m, uint8_t *), len);
2434 	return (m);
2435 }
2436 
2437 /*
2438  * Update private information that is derived from other private information
2439  */
2440 static void
2441 ng_ppp_update(node_p node, int newConf)
2442 {
2443 	const priv_p priv = NG_NODE_PRIVATE(node);
2444 	int i;
2445 
2446 	/* Update active status for VJ Compression */
2447 	priv->vjCompHooked = priv->hooks[HOOK_INDEX_VJC_IP] != NULL
2448 	    && priv->hooks[HOOK_INDEX_VJC_COMP] != NULL
2449 	    && priv->hooks[HOOK_INDEX_VJC_UNCOMP] != NULL
2450 	    && priv->hooks[HOOK_INDEX_VJC_VJIP] != NULL;
2451 
2452 	/* Increase latency for each link an amount equal to one MP header */
2453 	if (newConf) {
2454 		for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
2455 			int hdrBytes;
2456 
2457 			if (priv->links[i].conf.bandwidth == 0)
2458 			    continue;
2459 
2460 			hdrBytes = MP_AVERAGE_LINK_OVERHEAD
2461 			    + (priv->links[i].conf.enableACFComp ? 0 : 2)
2462 			    + (priv->links[i].conf.enableProtoComp ? 1 : 2)
2463 			    + (priv->conf.xmitShortSeq ? 2 : 4);
2464 			priv->links[i].latency =
2465 			    priv->links[i].conf.latency +
2466 			    (hdrBytes / priv->links[i].conf.bandwidth + 50) / 100;
2467 		}
2468 	}
2469 
2470 	/* Update list of active links */
2471 	bzero(&priv->activeLinks, sizeof(priv->activeLinks));
2472 	priv->numActiveLinks = 0;
2473 	priv->allLinksEqual = 1;
2474 	for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
2475 		struct ng_ppp_link *const link = &priv->links[i];
2476 
2477 		/* Is link active? */
2478 		if (link->conf.enableLink && link->hook != NULL) {
2479 			struct ng_ppp_link *link0;
2480 
2481 			/* Add link to list of active links */
2482 			priv->activeLinks[priv->numActiveLinks++] = i;
2483 			link0 = &priv->links[priv->activeLinks[0]];
2484 
2485 			/* Determine if all links are still equal */
2486 			if (link->latency != link0->latency
2487 			  || link->conf.bandwidth != link0->conf.bandwidth)
2488 				priv->allLinksEqual = 0;
2489 
2490 			/* Initialize rec'd sequence number */
2491 			if (link->seq == MP_NOSEQ) {
2492 				link->seq = (link == link0) ?
2493 				    MP_INITIAL_SEQ : link0->seq;
2494 			}
2495 		} else
2496 			link->seq = MP_NOSEQ;
2497 	}
2498 
2499 	/* Update MP state as multi-link is active or not */
2500 	if (priv->conf.enableMultilink && priv->numActiveLinks > 0)
2501 		ng_ppp_start_frag_timer(node);
2502 	else {
2503 		ng_ppp_stop_frag_timer(node);
2504 		ng_ppp_frag_reset(node);
2505 		priv->xseq = MP_INITIAL_SEQ;
2506 		priv->mseq = MP_INITIAL_SEQ;
2507 		for (i = 0; i < NG_PPP_MAX_LINKS; i++) {
2508 			struct ng_ppp_link *const link = &priv->links[i];
2509 
2510 			bzero(&link->lastWrite, sizeof(link->lastWrite));
2511 			link->bytesInQueue = 0;
2512 			link->seq = MP_NOSEQ;
2513 		}
2514 	}
2515 }
2516 
2517 /*
2518  * Determine if a new configuration would represent a valid change
2519  * from the current configuration and link activity status.
2520  */
2521 static int
2522 ng_ppp_config_valid(node_p node, const struct ng_ppp_node_conf *newConf)
2523 {
2524 	const priv_p priv = NG_NODE_PRIVATE(node);
2525 	int i, newNumLinksActive;
2526 
2527 	/* Check per-link config and count how many links would be active */
2528 	for (newNumLinksActive = i = 0; i < NG_PPP_MAX_LINKS; i++) {
2529 		if (newConf->links[i].enableLink && priv->links[i].hook != NULL)
2530 			newNumLinksActive++;
2531 		if (!newConf->links[i].enableLink)
2532 			continue;
2533 		if (newConf->links[i].mru < MP_MIN_LINK_MRU)
2534 			return (0);
2535 		if (newConf->links[i].bandwidth == 0)
2536 			return (0);
2537 		if (newConf->links[i].bandwidth > NG_PPP_MAX_BANDWIDTH)
2538 			return (0);
2539 		if (newConf->links[i].latency > NG_PPP_MAX_LATENCY)
2540 			return (0);
2541 	}
2542 
2543 	/* Check bundle parameters */
2544 	if (newConf->bund.enableMultilink && newConf->bund.mrru < MP_MIN_MRRU)
2545 		return (0);
2546 
2547 	/* Disallow changes to multi-link configuration while MP is active */
2548 	if (priv->numActiveLinks > 0 && newNumLinksActive > 0) {
2549 		if (!priv->conf.enableMultilink
2550 				!= !newConf->bund.enableMultilink
2551 		    || !priv->conf.xmitShortSeq != !newConf->bund.xmitShortSeq
2552 		    || !priv->conf.recvShortSeq != !newConf->bund.recvShortSeq)
2553 			return (0);
2554 	}
2555 
2556 	/* At most one link can be active unless multi-link is enabled */
2557 	if (!newConf->bund.enableMultilink && newNumLinksActive > 1)
2558 		return (0);
2559 
2560 	/* Configuration change would be valid */
2561 	return (1);
2562 }
2563 
2564 /*
2565  * Free all entries in the fragment queue
2566  */
2567 static void
2568 ng_ppp_frag_reset(node_p node)
2569 {
2570 	const priv_p priv = NG_NODE_PRIVATE(node);
2571 	struct ng_ppp_frag *qent, *qnext;
2572 
2573 	for (qent = TAILQ_FIRST(&priv->frags); qent; qent = qnext) {
2574 		qnext = TAILQ_NEXT(qent, f_qent);
2575 		NG_FREE_M(qent->data);
2576 		TAILQ_INSERT_HEAD(&priv->fragsfree, qent, f_qent);
2577 	}
2578 	TAILQ_INIT(&priv->frags);
2579 }
2580 
2581 /*
2582  * Start fragment queue timer
2583  */
2584 static void
2585 ng_ppp_start_frag_timer(node_p node)
2586 {
2587 	const priv_p priv = NG_NODE_PRIVATE(node);
2588 
2589 	if (!(callout_pending(&priv->fragTimer)))
2590 		ng_callout(&priv->fragTimer, node, NULL, MP_FRAGTIMER_INTERVAL,
2591 		    ng_ppp_frag_timeout, NULL, 0);
2592 }
2593 
2594 /*
2595  * Stop fragment queue timer
2596  */
2597 static void
2598 ng_ppp_stop_frag_timer(node_p node)
2599 {
2600 	const priv_p priv = NG_NODE_PRIVATE(node);
2601 
2602 	if (callout_pending(&priv->fragTimer))
2603 		ng_uncallout(&priv->fragTimer, node);
2604 }
2605