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Remove unnecessary argument.
[dragonfly.git] / sys / netgraph / l2tp / ng_l2tp.c
blob5a9a28f7807ccc76250ae216e12e88d566d1aa08
1
2 /*
3 * Copyright (c) 2001-2002 Packet Design, LLC.
4 * All rights reserved.
5 *
6 * Subject to the following obligations and disclaimer of warranty,
7 * use and redistribution of this software, in source or object code
8 * forms, with or without modifications are expressly permitted by
9 * Packet Design; provided, however, that:
10 *
11 * (i) Any and all reproductions of the source or object code
12 * must include the copyright notice above and the following
13 * disclaimer of warranties; and
14 * (ii) No rights are granted, in any manner or form, to use
15 * Packet Design trademarks, including the mark "PACKET DESIGN"
16 * on advertising, endorsements, or otherwise except as such
17 * appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
22 * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
23 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
24 * OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
25 * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
26 * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
27 * RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
28 * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
29 * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
30 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
31 * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
32 * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
33 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
35 * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
36 * THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * Author: Archie Cobbs <archie@freebsd.org>
39 *
40 * $FreeBSD: src/sys/netgraph/ng_l2tp.c,v 1.1.2.1 2002/08/20 23:48:15 archie Exp $
41 * $DragonFly: src/sys/netgraph/l2tp/ng_l2tp.c,v 1.8 2006/01/14 11:10:47 swildner Exp $
42 */
43
44 /*
45 * L2TP netgraph node type.
46 *
47 * This node type implements the lower layer of the
48 * L2TP protocol as specified in RFC 2661.
49 */
50
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/kernel.h>
54 #include <sys/time.h>
55 #include <sys/conf.h>
56 #include <sys/mbuf.h>
57 #include <sys/malloc.h>
58 #include <sys/errno.h>
59 #include <sys/libkern.h>
60 #include <sys/thread2.h>
61
62 #include <netgraph/ng_message.h>
63 #include <netgraph/netgraph.h>
64 #include <netgraph/ng_parse.h>
65 #include "ng_l2tp.h"
66
67 #ifdef NG_SEPARATE_MALLOC
68 MALLOC_DEFINE(M_NETGRAPH_L2TP, "netgraph_l2tp", "netgraph l2tp node");
69 #else
70 #define M_NETGRAPH_L2TP M_NETGRAPH
71 #endif
72
73 /* L2TP header format (first 2 bytes only) */
74 #define L2TP_HDR_CTRL 0x8000 /* control packet */
75 #define L2TP_HDR_LEN 0x4000 /* has length field */
76 #define L2TP_HDR_SEQ 0x0800 /* has ns, nr fields */
77 #define L2TP_HDR_OFF 0x0200 /* has offset field */
78 #define L2TP_HDR_PRIO 0x0100 /* give priority */
79 #define L2TP_HDR_VERS_MASK 0x000f /* version field mask */
80 #define L2TP_HDR_VERSION 0x0002 /* version field */
81
82 /* Bits that must be zero or one in first two bytes of header */
83 #define L2TP_CTRL_0BITS 0x030d /* ctrl: must be 0 */
84 #define L2TP_CTRL_1BITS 0xc802 /* ctrl: must be 1 */
85 #define L2TP_DATA_0BITS 0x800d /* data: must be 0 */
86 #define L2TP_DATA_1BITS 0x0002 /* data: must be 1 */
87
88 /* Standard xmit ctrl and data header bits */
89 #define L2TP_CTRL_HDR (L2TP_HDR_CTRL | L2TP_HDR_LEN \
90 | L2TP_HDR_SEQ | L2TP_HDR_VERSION)
91 #define L2TP_DATA_HDR (L2TP_HDR_VERSION) /* optional: len, seq */
92
93 /* Some hard coded values */
94 #define L2TP_MAX_XWIN 16 /* my max xmit window */
95 #define L2TP_MAX_REXMIT 5 /* default max rexmit */
96 #define L2TP_MAX_REXMIT_TO 30 /* default rexmit to */
97 #define L2TP_DELAYED_ACK ((hz + 19) / 20) /* delayed ack: 50 ms */
98
99 /* Default data sequence number configuration for new sessions */
100 #define L2TP_CONTROL_DSEQ 1 /* we are the lns */
101 #define L2TP_ENABLE_DSEQ 1 /* enable data seq # */
102
103 /* Compare sequence numbers using circular math */
104 #define L2TP_SEQ_DIFF(x, y) ((int)((int16_t)(x) - (int16_t)(y)))
105
106 /*
107 * Sequence number state
108 *
109 * Invariants:
110 * - If cwnd < ssth, we're doing slow start, otherwise congestion avoidance
111 * - The number of unacknowledged xmit packets is (ns - rack) <= seq->wmax
112 * - The first (ns - rack) mbuf's in xwin[] array are copies of these
113 * unacknowledged packets; the remainder of xwin[] consists first of
114 * zero or more further untransmitted packets in the transmit queue
115 * - We try to keep the peer's receive window as full as possible.
116 * Therefore, (i < cwnd && xwin[i] != NULL) implies (ns - rack) > i.
117 * - rack_timer is running iff (ns - rack) > 0 (unack'd xmit'd pkts)
118 * - If xack != nr, there are unacknowledged recv packet(s) (delayed ack)
119 * - xack_timer is running iff xack != nr (unack'd rec'd pkts)
120 */
121 struct l2tp_seq {
122 u_int16_t ns; /* next xmit seq we send */
123 u_int16_t nr; /* next recv seq we expect */
124 u_int16_t rack; /* last 'nr' we rec'd */
125 u_int16_t xack; /* last 'nr' we sent */
126 u_int16_t wmax; /* peer's max recv window */
127 u_int16_t cwnd; /* current congestion window */
128 u_int16_t ssth; /* slow start threshold */
129 u_int16_t acks; /* # consecutive acks rec'd */
130 u_int16_t rexmits; /* # retransmits sent */
131 u_int16_t max_rexmits; /* max # retransmits sent */
132 u_int16_t max_rexmit_to; /* max retransmit timeout */
133 struct callout rack_timer; /* retransmit timer */
134 struct callout xack_timer; /* delayed ack timer */
135 u_char rack_timer_running; /* xmit timer running */
136 u_char xack_timer_running; /* ack timer running */
137 struct mbuf *xwin[L2TP_MAX_XWIN]; /* transmit window */
138 };
139
140 /* Node private data */
141 struct ng_l2tp_private {
142 node_p node; /* back pointer to node */
143 hook_p ctrl; /* hook to upper layers */
144 hook_p lower; /* hook to lower layers */
145 struct ng_l2tp_config conf; /* node configuration */
146 struct ng_l2tp_stats stats; /* node statistics */
147 struct l2tp_seq seq; /* ctrl sequence number state */
148 char *ftarget; /* failure message target */
149 };
150 typedef struct ng_l2tp_private *priv_p;
151
152 /* Hook private data (data session hooks only) */
153 struct ng_l2tp_hook_private {
154 struct ng_l2tp_sess_config conf; /* hook/session config */
155 u_int16_t ns; /* data ns sequence number */
156 u_int16_t nr; /* data nr sequence number */
157 };
158 typedef struct ng_l2tp_hook_private *hookpriv_p;
159
160 /* Netgraph node methods */
161 static ng_constructor_t ng_l2tp_constructor;
162 static ng_rcvmsg_t ng_l2tp_rcvmsg;
163 static ng_shutdown_t ng_l2tp_shutdown;
164 static ng_newhook_t ng_l2tp_newhook;
165 static ng_rcvdata_t ng_l2tp_rcvdata;
166 static ng_disconnect_t ng_l2tp_disconnect;
167
168 /* Internal functions */
169 static int ng_l2tp_recv_lower(node_p node, struct mbuf *m, meta_p meta);
170 static int ng_l2tp_recv_ctrl(node_p node, struct mbuf *m, meta_p meta);
171 static int ng_l2tp_recv_data(node_p node,
172 struct mbuf *m, meta_p meta, hookpriv_p hpriv);
173
174 static int ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns);
175
176 static void ng_l2tp_seq_init(priv_p priv);
177 static int ng_l2tp_seq_adjust(priv_p priv,
178 const struct ng_l2tp_config *conf);
179 static void ng_l2tp_seq_reset(priv_p priv);
180 static void ng_l2tp_seq_failure(priv_p priv);
181 static void ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr);
182 static int ng_l2tp_seq_recv_ns(priv_p priv, u_int16_t ns);
183 static void ng_l2tp_seq_xack_timeout(void *arg);
184 static void ng_l2tp_seq_rack_timeout(void *arg);
185
186 #ifdef INVARIANTS
187 static void ng_l2tp_seq_check(struct l2tp_seq *seq);
188 #endif
189
190 /* Parse type for struct ng_l2tp_config */
191 static const struct ng_parse_struct_field
192 ng_l2tp_config_type_fields[] = NG_L2TP_CONFIG_TYPE_INFO;
193 static const struct ng_parse_type ng_l2tp_config_type = {
194 &ng_parse_struct_type,
195 &ng_l2tp_config_type_fields,
196 };
197
198 /* Parse type for struct ng_l2tp_sess_config */
199 static const struct ng_parse_struct_field
200 ng_l2tp_sess_config_type_fields[] = NG_L2TP_SESS_CONFIG_TYPE_INFO;
201 static const struct ng_parse_type ng_l2tp_sess_config_type = {
202 &ng_parse_struct_type,
203 &ng_l2tp_sess_config_type_fields,
204 };
205
206 /* Parse type for struct ng_l2tp_stats */
207 static const struct ng_parse_struct_field
208 ng_l2tp_stats_type_fields[] = NG_L2TP_STATS_TYPE_INFO;
209 static const struct ng_parse_type ng_pptp_stats_type = {
210 &ng_parse_struct_type,
211 &ng_l2tp_stats_type_fields
212 };
213
214 /* List of commands and how to convert arguments to/from ASCII */
215 static const struct ng_cmdlist ng_l2tp_cmdlist[] = {
216 {
217 NGM_L2TP_COOKIE,
218 NGM_L2TP_SET_CONFIG,
219 "setconfig",
220 &ng_l2tp_config_type,
221 NULL
222 },
223 {
224 NGM_L2TP_COOKIE,
225 NGM_L2TP_GET_CONFIG,
226 "getconfig",
227 NULL,
228 &ng_l2tp_config_type
229 },
230 {
231 NGM_L2TP_COOKIE,
232 NGM_L2TP_SET_SESS_CONFIG,
233 "setsessconfig",
234 &ng_l2tp_sess_config_type,
235 NULL
236 },
237 {
238 NGM_L2TP_COOKIE,
239 NGM_L2TP_GET_SESS_CONFIG,
240 "getsessconfig",
241 &ng_parse_hint16_type,
242 &ng_l2tp_sess_config_type
243 },
244 {
245 NGM_L2TP_COOKIE,
246 NGM_L2TP_GET_STATS,
247 "getstats",
248 NULL,
249 &ng_pptp_stats_type
250 },
251 {
252 NGM_L2TP_COOKIE,
253 NGM_L2TP_CLR_STATS,
254 "clrstats",
255 NULL,
256 NULL
257 },
258 {
259 NGM_L2TP_COOKIE,
260 NGM_L2TP_GETCLR_STATS,
261 "getclrstats",
262 NULL,
263 &ng_pptp_stats_type
264 },
265 {
266 NGM_L2TP_COOKIE,
267 NGM_L2TP_ACK_FAILURE,
268 "ackfailure",
269 NULL,
270 NULL
271 },
272 { 0 }
273 };
274
275 /* Node type descriptor */
276 static struct ng_type ng_l2tp_typestruct = {
277 NG_VERSION,
278 NG_L2TP_NODE_TYPE,
279 NULL,
280 ng_l2tp_constructor,
281 ng_l2tp_rcvmsg,
282 ng_l2tp_shutdown,
283 ng_l2tp_newhook,
284 NULL,
285 NULL,
286 ng_l2tp_rcvdata,
287 ng_l2tp_rcvdata,
288 ng_l2tp_disconnect,
289 ng_l2tp_cmdlist
290 };
291 NETGRAPH_INIT(l2tp, &ng_l2tp_typestruct);
292
293 /* Sequence number state sanity checking */
294 #ifdef INVARIANTS
295 #define L2TP_SEQ_CHECK(seq) ng_l2tp_seq_check(seq)
296 #else
297 #define L2TP_SEQ_CHECK(x) do { } while (0)
298 #endif
299
300 /* memmove macro */
301 #define memmove(d, s, l) ovbcopy(s, d, l)
302
303 /* Whether to use m_copypacket() or m_dup() */
304 #define L2TP_COPY_MBUF m_copypacket
305
306 /************************************************************************
307 NETGRAPH NODE STUFF
308 ************************************************************************/
309
310 /*
311 * Node type constructor
312 */
313 static int
314 ng_l2tp_constructor(node_p *nodep)
315 {
316 priv_p priv;
317 int error;
318
319 /* Allocate private structure */
320 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_L2TP, M_NOWAIT | M_ZERO);
321 if (priv == NULL)
322 return (ENOMEM);
323
324 /* Apply a semi-reasonable default configuration */
325 priv->conf.peer_win = 1;
326 priv->conf.rexmit_max = L2TP_MAX_REXMIT;
327 priv->conf.rexmit_max_to = L2TP_MAX_REXMIT_TO;
328
329 /* Initialize sequence number state */
330 ng_l2tp_seq_init(priv);
331
332 /* Call generic node constructor */
333 if ((error = ng_make_node_common(&ng_l2tp_typestruct, nodep))) {
334 FREE(priv, M_NETGRAPH_L2TP);
335 return (error);
336 }
337 NG_NODE_SET_PRIVATE(*nodep, priv);
338 priv->node = *nodep;
339
340 /* Done */
341 return (0);
342 }
343
344 /*
345 * Give our OK for a hook to be added.
346 */
347 static int
348 ng_l2tp_newhook(node_p node, hook_p hook, const char *name)
349 {
350 const priv_p priv = NG_NODE_PRIVATE(node);
351
352 /* Check hook name */
353 if (strcmp(name, NG_L2TP_HOOK_CTRL) == 0) {
354 if (priv->ctrl != NULL)
355 return (EISCONN);
356 priv->ctrl = hook;
357 } else if (strcmp(name, NG_L2TP_HOOK_LOWER) == 0) {
358 if (priv->lower != NULL)
359 return (EISCONN);
360 priv->lower = hook;
361 } else {
362 static const char hexdig[16] = "0123456789abcdef";
363 u_int16_t session_id;
364 hookpriv_p hpriv;
365 const char *hex;
366 int i;
367 int j;
368
369 /* Parse hook name to get session ID */
370 if (strncmp(name, NG_L2TP_HOOK_SESSION_P,
371 sizeof(NG_L2TP_HOOK_SESSION_P) - 1) != 0)
372 return (EINVAL);
373 hex = name + sizeof(NG_L2TP_HOOK_SESSION_P) - 1;
374 for (session_id = i = 0; i < 4; i++) {
375 for (j = 0; j < 16 && hex[i] != hexdig[j]; j++);
376 if (j == 16)
377 return (EINVAL);
378 session_id = (session_id << 4) | j;
379 }
380 if (hex[i] != '\0')
381 return (EINVAL);
382
383 /* Create hook private structure */
384 MALLOC(hpriv, hookpriv_p,
385 sizeof(*hpriv), M_NETGRAPH_L2TP, M_NOWAIT | M_ZERO);
386 if (hpriv == NULL)
387 return (ENOMEM);
388 hpriv->conf.session_id = htons(session_id);
389 hpriv->conf.control_dseq = L2TP_CONTROL_DSEQ;
390 hpriv->conf.enable_dseq = L2TP_ENABLE_DSEQ;
391 NG_HOOK_SET_PRIVATE(hook, hpriv);
392 }
393
394 /* Done */
395 return (0);
396 }
397
398 /*
399 * Receive a control message.
400 */
401 static int
402 ng_l2tp_rcvmsg(node_p node, struct ng_mesg *msg,
403 const char *raddr, struct ng_mesg **rptr)
404 {
405 const priv_p priv = NG_NODE_PRIVATE(node);
406 struct ng_mesg *resp = NULL;
407 int error = 0;
408
409 switch (msg->header.typecookie) {
410 case NGM_L2TP_COOKIE:
411 switch (msg->header.cmd) {
412 case NGM_L2TP_SET_CONFIG:
413 {
414 struct ng_l2tp_config *const conf =
415 (struct ng_l2tp_config *)msg->data;
416
417 /* Check for invalid or illegal config */
418 if (msg->header.arglen != sizeof(*conf)) {
419 error = EINVAL;
420 break;
421 }
422 conf->enabled = !!conf->enabled;
423 conf->match_id = !!conf->match_id;
424 conf->tunnel_id = htons(conf->tunnel_id);
425 conf->peer_id = htons(conf->peer_id);
426 if (priv->conf.enabled
427 && ((priv->conf.tunnel_id != 0
428 && conf->tunnel_id != priv->conf.tunnel_id)
429 || ((priv->conf.peer_id != 0
430 && conf->peer_id != priv->conf.peer_id)))) {
431 error = EBUSY;
432 break;
433 }
434
435 /* Save calling node as failure target */
436 if (priv->ftarget != NULL)
437 FREE(priv->ftarget, M_NETGRAPH_L2TP);
438 MALLOC(priv->ftarget, char *,
439 strlen(raddr) + 1, M_NETGRAPH_L2TP, M_NOWAIT);
440 if (priv->ftarget == NULL) {
441 error = ENOMEM;
442 break;
443 }
444 strcpy(priv->ftarget, raddr);
445
446 /* Adjust sequence number state */
447 if ((error = ng_l2tp_seq_adjust(priv, conf)) != 0)
448 break;
449
450 /* Update node's config */
451 priv->conf = *conf;
452 break;
453 }
454 case NGM_L2TP_GET_CONFIG:
455 {
456 struct ng_l2tp_config *conf;
457
458 NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT);
459 if (resp == NULL) {
460 error = ENOMEM;
461 break;
462 }
463 conf = (struct ng_l2tp_config *)resp->data;
464 *conf = priv->conf;
465
466 /* Put ID's in host order */
467 conf->tunnel_id = ntohs(conf->tunnel_id);
468 conf->peer_id = ntohs(conf->peer_id);
469 break;
470 }
471 case NGM_L2TP_SET_SESS_CONFIG:
472 {
473 struct ng_l2tp_sess_config *const conf =
474 (struct ng_l2tp_sess_config *)msg->data;
475 hookpriv_p hpriv = NULL;
476 hook_p hook;
477
478 /* Check for invalid or illegal config */
479 if (msg->header.arglen != sizeof(*conf)) {
480 error = EINVAL;
481 break;
482 }
483
484 /* Put ID's in network order */
485 conf->session_id = htons(conf->session_id);
486 conf->peer_id = htons(conf->peer_id);
487
488 /* Find matching hook */
489 LIST_FOREACH(hook, &node->hooks, hooks) {
490 if ((hpriv = NG_HOOK_PRIVATE(hook)) == NULL)
491 continue;
492 if (hpriv->conf.session_id == conf->session_id)
493 break;
494 }
495 if (hook == NULL) {
496 error = ENOENT;
497 break;
498 }
499
500 /* Update hook's config */
501 hpriv->conf = *conf;
502 break;
503 }
504 case NGM_L2TP_GET_SESS_CONFIG:
505 {
506 struct ng_l2tp_sess_config *conf;
507 hookpriv_p hpriv = NULL;
508 u_int16_t session_id;
509 hook_p hook;
510
511 /* Get session ID */
512 if (msg->header.arglen != sizeof(session_id)) {
513 error = EINVAL;
514 break;
515 }
516 memcpy(&session_id, msg->data, 2);
517 session_id = htons(session_id);
518
519 /* Find matching hook */
520 LIST_FOREACH(hook, &node->hooks, hooks) {
521 if ((hpriv = NG_HOOK_PRIVATE(hook)) == NULL)
522 continue;
523 if (hpriv->conf.session_id == session_id)
524 break;
525 }
526 if (hook == NULL) {
527 error = ENOENT;
528 break;
529 }
530
531 /* Send response */
532 NG_MKRESPONSE(resp, msg, sizeof(hpriv->conf), M_NOWAIT);
533 if (resp == NULL) {
534 error = ENOMEM;
535 break;
536 }
537 conf = (struct ng_l2tp_sess_config *)resp->data;
538 *conf = hpriv->conf;
539
540 /* Put ID's in host order */
541 conf->session_id = ntohs(conf->session_id);
542 conf->peer_id = ntohs(conf->peer_id);
543 break;
544 }
545 case NGM_L2TP_GET_STATS:
546 case NGM_L2TP_CLR_STATS:
547 case NGM_L2TP_GETCLR_STATS:
548 {
549 if (msg->header.cmd != NGM_L2TP_CLR_STATS) {
550 NG_MKRESPONSE(resp, msg,
551 sizeof(priv->stats), M_NOWAIT);
552 if (resp == NULL) {
553 error = ENOMEM;
554 break;
555 }
556 memcpy(resp->data,
557 &priv->stats, sizeof(priv->stats));
558 }
559 if (msg->header.cmd != NGM_L2TP_GET_STATS)
560 memset(&priv->stats, 0, sizeof(priv->stats));
561 break;
562 }
563 default:
564 error = EINVAL;
565 break;
566 }
567 break;
568 default:
569 error = EINVAL;
570 break;
571 }
572 if (rptr)
573 *rptr = resp;
574 else if (resp)
575 FREE(resp, M_NETGRAPH);
576 FREE(msg, M_NETGRAPH);
577 return (error);
578 }
579
580 /*
581 * Receive incoming data on a hook.
582 */
583 static int
584 ng_l2tp_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
585 {
586 const node_p node = NG_HOOK_NODE(hook);
587 const priv_p priv = NG_NODE_PRIVATE(node);
588 int error;
589
590 /* Sanity check */
591 L2TP_SEQ_CHECK(&priv->seq);
592
593 /* If not configured, reject */
594 if (!priv->conf.enabled) {
595 NG_FREE_DATA(m, meta);
596 return (ENXIO);
597 }
598
599 /* Handle incoming frame from below */
600 if (hook == priv->lower) {
601 error = ng_l2tp_recv_lower(node, m, meta);
602 goto done;
603 }
604
605 /* Handle outgoing control frame */
606 if (hook == priv->ctrl) {
607 error = ng_l2tp_recv_ctrl(node, m, meta);
608 goto done;
609 }
610
611 /* Handle outgoing data frame */
612 error = ng_l2tp_recv_data(node, m, meta, NG_HOOK_PRIVATE(hook));
613
614 done:
615 /* Done */
616 L2TP_SEQ_CHECK(&priv->seq);
617 return (error);
618 }
619
620 /*
621 * Destroy node
622 */
623 static int
624 ng_l2tp_shutdown(node_p node)
625 {
626 const priv_p priv = NG_NODE_PRIVATE(node);
627 struct l2tp_seq *const seq = &priv->seq;
628
629 /* Sanity check */
630 L2TP_SEQ_CHECK(seq);
631
632 /* Reset sequence number state */
633 node->flags |= NG_INVALID;
634 ng_l2tp_seq_reset(priv);
635 ng_cutlinks(node);
636 ng_unname(node);
637
638 /* Free private data if neither timer is running */
639 if (!seq->rack_timer_running && !seq->xack_timer_running) {
640 if (priv->ftarget != NULL)
641 FREE(priv->ftarget, M_NETGRAPH_L2TP);
642 FREE(priv, M_NETGRAPH_L2TP);
643 NG_NODE_SET_PRIVATE(node, NULL);
644 }
645
646 /* Unref node */
647 NG_NODE_UNREF(node);
648 return (0);
649 }
650
651 /*
652 * Hook disconnection
653 */
654 static int
655 ng_l2tp_disconnect(hook_p hook)
656 {
657 const node_p node = NG_HOOK_NODE(hook);
658 const priv_p priv = NG_NODE_PRIVATE(node);
659
660 /* Zero out hook pointer */
661 if (hook == priv->ctrl)
662 priv->ctrl = NULL;
663 else if (hook == priv->lower)
664 priv->lower = NULL;
665 else {
666 FREE(NG_HOOK_PRIVATE(hook), M_NETGRAPH_L2TP);
667 NG_HOOK_SET_PRIVATE(hook, NULL);
668 }
669
670 /* Go away if no longer connected to anything */
671 if (node->numhooks == 0)
672 ng_rmnode(node);
673 return (0);
674 }
675
676 /*************************************************************************
677 INTERNAL FUNCTIONS
678 *************************************************************************/
679
680 /*
681 * Handle an incoming frame from below.
682 */
683 static int
684 ng_l2tp_recv_lower(node_p node, struct mbuf *m, meta_p meta)
685 {
686 static const u_int16_t req_bits[2][2] = {
687 { L2TP_DATA_0BITS, L2TP_DATA_1BITS },
688 { L2TP_CTRL_0BITS, L2TP_CTRL_1BITS },
689 };
690 const priv_p priv = NG_NODE_PRIVATE(node);
691 hookpriv_p hpriv = NULL;
692 hook_p hook = NULL;
693 u_int16_t ids[2];
694 u_int16_t hdr;
695 u_int16_t ns;
696 u_int16_t nr;
697 int is_ctrl;
698 int error;
699 int len;
700
701 /* Update stats */
702 priv->stats.recvPackets++;
703 priv->stats.recvOctets += m->m_pkthdr.len;
704
705 /* Get initial header */
706 if (m->m_pkthdr.len < 6) {
707 priv->stats.recvRunts++;
708 NG_FREE_DATA(m, meta);
709 return (EINVAL);
710 }
711 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
712 priv->stats.memoryFailures++;
713 NG_FREE_META(meta);
714 return (EINVAL);
715 }
716 hdr = ntohs(*mtod(m, u_int16_t *));
717 m_adj(m, 2);
718
719 /* Check required header bits and minimum length */
720 is_ctrl = (hdr & L2TP_HDR_CTRL) != 0;
721 if ((hdr & req_bits[is_ctrl][0]) != 0
722 || (~hdr & req_bits[is_ctrl][1]) != 0) {
723 priv->stats.recvInvalid++;
724 NG_FREE_DATA(m, meta);
725 return (EINVAL);
726 }
727 if (m->m_pkthdr.len < 4 /* tunnel, session id */
728 + (2 * ((hdr & L2TP_HDR_LEN) != 0)) /* length field */
729 + (4 * ((hdr & L2TP_HDR_SEQ) != 0)) /* seq # fields */
730 + (2 * ((hdr & L2TP_HDR_OFF) != 0))) { /* offset field */
731 priv->stats.recvRunts++;
732 NG_FREE_DATA(m, meta);
733 return (EINVAL);
734 }
735
736 /* Get and validate length field if present */
737 if ((hdr & L2TP_HDR_LEN) != 0) {
738 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
739 priv->stats.memoryFailures++;
740 NG_FREE_META(meta);
741 return (EINVAL);
742 }
743 len = (u_int16_t)ntohs(*mtod(m, u_int16_t *)) - 4;
744 m_adj(m, 2);
745 if (len < 0 || len > m->m_pkthdr.len) {
746 priv->stats.recvInvalid++;
747 NG_FREE_DATA(m, meta);
748 return (EINVAL);
749 }
750 if (len < m->m_pkthdr.len) /* trim extra bytes */
751 m_adj(m, -(m->m_pkthdr.len - len));
752 }
753
754 /* Get tunnel ID and session ID */
755 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
756 priv->stats.memoryFailures++;
757 NG_FREE_META(meta);
758 return (EINVAL);
759 }
760 memcpy(ids, mtod(m, u_int16_t *), 4);
761 m_adj(m, 4);
762
763 /* Check tunnel ID */
764 if (ids[0] != priv->conf.tunnel_id
765 && (priv->conf.match_id || ids[0] != 0)) {
766 priv->stats.recvWrongTunnel++;
767 NG_FREE_DATA(m, meta);
768 return (EADDRNOTAVAIL);
769 }
770
771 /* Check session ID (for data packets only) */
772 if ((hdr & L2TP_HDR_CTRL) == 0) {
773 LIST_FOREACH(hook, &node->hooks, hooks) {
774 if ((hpriv = NG_HOOK_PRIVATE(hook)) == NULL)
775 continue;
776 if (hpriv->conf.session_id == ids[1])
777 break;
778 }
779 if (hook == NULL) {
780 priv->stats.recvUnknownSID++;
781 NG_FREE_DATA(m, meta);
782 return (ENOTCONN);
783 }
784 hpriv = NG_HOOK_PRIVATE(hook);
785 }
786
787 /* Get Ns, Nr fields if present */
788 if ((hdr & L2TP_HDR_SEQ) != 0) {
789 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
790 priv->stats.memoryFailures++;
791 NG_FREE_META(meta);
792 return (EINVAL);
793 }
794 memcpy(&ns, &mtod(m, u_int16_t *)[0], 2);
795 ns = ntohs(ns);
796 memcpy(&nr, &mtod(m, u_int16_t *)[1], 2);
797 nr = ntohs(nr);
798 m_adj(m, 4);
799 }
800
801 /* Strip offset padding if present */
802 if ((hdr & L2TP_HDR_OFF) != 0) {
803 u_int16_t offset;
804
805 /* Get length of offset padding */
806 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
807 priv->stats.memoryFailures++;
808 NG_FREE_META(meta);
809 return (EINVAL);
810 }
811 memcpy(&offset, mtod(m, u_int16_t *), 2);
812 offset = ntohs(offset);
813
814 /* Trim offset padding */
815 if (offset <= 2 || offset > m->m_pkthdr.len) {
816 priv->stats.recvInvalid++;
817 NG_FREE_DATA(m, meta);
818 return (EINVAL);
819 }
820 m_adj(m, offset);
821 }
822
823 /* Handle control packets */
824 if ((hdr & L2TP_HDR_CTRL) != 0) {
825
826 /* Handle receive ack sequence number Nr */
827 ng_l2tp_seq_recv_nr(priv, nr);
828
829 /* Discard ZLB packets */
830 if (m->m_pkthdr.len == 0) {
831 priv->stats.recvZLBs++;
832 NG_FREE_DATA(m, meta);
833 return (0);
834 }
835
836 /*
837 * Prepend session ID to packet here: we don't want to accept
838 * the send sequence number Ns if we have to drop the packet
839 * later because of a memory error, because then the upper
840 * layer would never get the packet.
841 */
842 M_PREPEND(m, 2, MB_DONTWAIT);
843 if (m == NULL) {
844 priv->stats.memoryFailures++;
845 NG_FREE_META(meta);
846 return (ENOBUFS);
847 }
848 memcpy(mtod(m, u_int16_t *), &ids[1], 2);
849
850 /* Now handle send sequence number */
851 if (ng_l2tp_seq_recv_ns(priv, ns) == -1) {
852 NG_FREE_DATA(m, meta);
853 return (0);
854 }
855
856 /* Deliver packet to upper layers */
857 NG_SEND_DATA(error, priv->ctrl, m, meta);
858 return (error);
859 }
860
861 /* Follow peer's lead in data sequencing, if configured to do so */
862 if (!hpriv->conf.control_dseq)
863 hpriv->conf.enable_dseq = ((hdr & L2TP_HDR_SEQ) != 0);
864
865 /* Handle data sequence numbers if present and enabled */
866 if ((hdr & L2TP_HDR_SEQ) != 0) {
867 if (hpriv->conf.enable_dseq
868 && L2TP_SEQ_DIFF(ns, hpriv->nr) < 0) {
869 NG_FREE_DATA(m, meta); /* duplicate or out of order */
870 priv->stats.recvDataDrops++;
871 return (0);
872 }
873 hpriv->nr = ns + 1;
874 }
875
876 /* Drop empty data packets */
877 if (m->m_pkthdr.len == 0) {
878 NG_FREE_DATA(m, meta);
879 return (0);
880 }
881
882 /* Deliver data */
883 NG_SEND_DATA(error, hook, m, meta);
884 return (error);
885 }
886
887 /*
888 * Handle an outgoing control frame.
889 */
890 static int
891 ng_l2tp_recv_ctrl(node_p node, struct mbuf *m, meta_p meta)
892 {
893 const priv_p priv = NG_NODE_PRIVATE(node);
894 struct l2tp_seq *const seq = &priv->seq;
895 int i;
896
897 /* Discard meta XXX should queue meta's along with packet */
898 NG_FREE_META(meta);
899
900 /* Packet should have session ID prepended */
901 if (m->m_pkthdr.len < 2) {
902 priv->stats.xmitInvalid++;
903 m_freem(m);
904 return (EINVAL);
905 }
906
907 /* Check max length */
908 if (m->m_pkthdr.len >= 0x10000 - 14) {
909 priv->stats.xmitTooBig++;
910 m_freem(m);
911 return (EOVERFLOW);
912 }
913
914 /* Find next empty slot in transmit queue */
915 for (i = 0; i < L2TP_MAX_XWIN && seq->xwin[i] != NULL; i++);
916 if (i == L2TP_MAX_XWIN) {
917 priv->stats.xmitDrops++;
918 m_freem(m);
919 return (ENOBUFS);
920 }
921 seq->xwin[i] = m;
922
923 /* Sanity check receive ack timer state */
924 KASSERT((i == 0) ^ seq->rack_timer_running,
925 ("%s: xwin %d full but rack timer %srunning",
926 __func__, i, seq->rack_timer_running ? "" : "not "));
927
928 /* If peer's receive window is already full, nothing else to do */
929 if (i >= seq->cwnd)
930 return (0);
931
932 /* Start retransmit timer if not already running */
933 if (!seq->rack_timer_running) {
934 callout_reset(&seq->rack_timer,
935 hz, ng_l2tp_seq_rack_timeout, node);
936 seq->rack_timer_running = 1;
937 NG_NODE_REF(node);
938 }
939
940 /* Copy packet */
941 if ((m = L2TP_COPY_MBUF(seq->xwin[i], MB_DONTWAIT)) == NULL) {
942 priv->stats.memoryFailures++;
943 return (ENOBUFS);
944 }
945
946 /* Send packet and increment xmit sequence number */
947 return (ng_l2tp_xmit_ctrl(priv, m, seq->ns++));
948 }
949
950 /*
951 * Handle an outgoing data frame.
952 */
953 static int
954 ng_l2tp_recv_data(node_p node, struct mbuf *m, meta_p meta, hookpriv_p hpriv)
955 {
956 const priv_p priv = NG_NODE_PRIVATE(node);
957 u_int16_t hdr;
958 int error;
959 int i = 1;
960
961 /* Check max length */
962 if (m->m_pkthdr.len >= 0x10000 - 12) {
963 priv->stats.xmitDataTooBig++;
964 NG_FREE_META(meta);
965 m_freem(m);
966 return (EOVERFLOW);
967 }
968
969 /* Prepend L2TP header */
970 M_PREPEND(m, 6
971 + (2 * (hpriv->conf.include_length != 0))
972 + (4 * (hpriv->conf.enable_dseq != 0)),
973 MB_DONTWAIT);
974 if (m == NULL) {
975 priv->stats.memoryFailures++;
976 NG_FREE_META(meta);
977 return (ENOBUFS);
978 }
979 hdr = L2TP_DATA_HDR;
980 if (hpriv->conf.include_length) {
981 hdr |= L2TP_HDR_LEN;
982 mtod(m, u_int16_t *)[i++] = htons(m->m_pkthdr.len);
983 }
984 mtod(m, u_int16_t *)[i++] = priv->conf.peer_id;
985 mtod(m, u_int16_t *)[i++] = hpriv->conf.peer_id;
986 if (hpriv->conf.enable_dseq) {
987 hdr |= L2TP_HDR_SEQ;
988 mtod(m, u_int16_t *)[i++] = htons(hpriv->ns);
989 mtod(m, u_int16_t *)[i++] = htons(hpriv->nr);
990 hpriv->ns++;
991 }
992 mtod(m, u_int16_t *)[0] = htons(hdr);
993
994 /* Send packet */
995 NG_SEND_DATA(error, priv->lower, m, meta);
996 return (error);
997 }
998
999 /*
1000 * Send a message to our controlling node that we've failed.
1001 */
1002 static void
1003 ng_l2tp_seq_failure(priv_p priv)
1004 {
1005 struct ng_mesg *msg;
1006
1007 NG_MKMESSAGE(msg, NGM_L2TP_COOKIE, NGM_L2TP_ACK_FAILURE, 0, M_NOWAIT);
1008 if (msg == NULL)
1009 return;
1010 ng_send_msg(priv->node, msg, priv->ftarget, NULL);
1011 }
1012
1013 /************************************************************************
1014 SEQUENCE NUMBER HANDLING
1015 ************************************************************************/
1016
1017 /*
1018 * Initialize sequence number state.
1019 */
1020 static void
1021 ng_l2tp_seq_init(priv_p priv)
1022 {
1023 struct l2tp_seq *const seq = &priv->seq;
1024
1025 KASSERT(priv->conf.peer_win >= 1,
1026 ("%s: peer_win is zero", __func__));
1027 memset(seq, 0, sizeof(*seq));
1028 seq->cwnd = 1;
1029 seq->wmax = priv->conf.peer_win;
1030 if (seq->wmax > L2TP_MAX_XWIN)
1031 seq->wmax = L2TP_MAX_XWIN;
1032 seq->ssth = seq->wmax;
1033 seq->max_rexmits = priv->conf.rexmit_max;
1034 seq->max_rexmit_to = priv->conf.rexmit_max_to;
1035 callout_init(&seq->rack_timer);
1036 callout_init(&seq->xack_timer);
1037 L2TP_SEQ_CHECK(seq);
1038 }
1039
1040 /*
1041 * Adjust sequence number state accordingly after reconfiguration.
1042 */
1043 static int
1044 ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf)
1045 {
1046 struct l2tp_seq *const seq = &priv->seq;
1047 u_int16_t new_wmax;
1048
1049 /* If disabling node, reset state sequence number */
1050 if (!conf->enabled) {
1051 ng_l2tp_seq_reset(priv);
1052 return (0);
1053 }
1054
1055 /* Adjust peer's max recv window; it can only increase */
1056 new_wmax = conf->peer_win;
1057 if (new_wmax > L2TP_MAX_XWIN)
1058 new_wmax = L2TP_MAX_XWIN;
1059 if (new_wmax == 0)
1060 return (EINVAL);
1061 if (new_wmax < seq->wmax)
1062 return (EBUSY);
1063 seq->wmax = new_wmax;
1064
1065 /* Update retransmit parameters */
1066 seq->max_rexmits = conf->rexmit_max;
1067 seq->max_rexmit_to = conf->rexmit_max_to;
1068
1069 /* Done */
1070 return (0);
1071 }
1072
1073 /*
1074 * Reset sequence number state.
1075 */
1076 static void
1077 ng_l2tp_seq_reset(priv_p priv)
1078 {
1079 struct l2tp_seq *const seq = &priv->seq;
1080 hookpriv_p hpriv = NULL;
1081 hook_p hook;
1082 int i;
1083
1084 /* Sanity check */
1085 L2TP_SEQ_CHECK(seq);
1086
1087 /* Stop timers */
1088 if (seq->rack_timer_running && callout_stop(&seq->rack_timer) == 1) {
1089 seq->rack_timer_running = 0;
1090 NG_NODE_UNREF(priv->node);
1091 }
1092 if (seq->xack_timer_running && callout_stop(&seq->xack_timer) == 1) {
1093 seq->xack_timer_running = 0;
1094 NG_NODE_UNREF(priv->node);
1095 }
1096
1097 /* Free retransmit queue */
1098 for (i = 0; i < L2TP_MAX_XWIN; i++) {
1099 if (seq->xwin[i] == NULL)
1100 break;
1101 m_freem(seq->xwin[i]);
1102 }
1103
1104 /* Reset session hooks' sequence number states */
1105 LIST_FOREACH(hook, &priv->node->hooks, hooks) {
1106 if ((hpriv = NG_HOOK_PRIVATE(hook)) == NULL)
1107 continue;
1108 hpriv->conf.control_dseq = 0;
1109 hpriv->conf.enable_dseq = 0;
1110 hpriv->nr = 0;
1111 hpriv->ns = 0;
1112 }
1113
1114 /* Reset node's sequence number state */
1115 memset(seq, 0, sizeof(*seq));
1116 seq->cwnd = 1;
1117 seq->wmax = L2TP_MAX_XWIN;
1118 seq->ssth = seq->wmax;
1119
1120 /* Done */
1121 L2TP_SEQ_CHECK(seq);
1122 }
1123
1124 /*
1125 * Handle receipt of an acknowledgement value (Nr) from peer.
1126 */
1127 static void
1128 ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
1129 {
1130 struct l2tp_seq *const seq = &priv->seq;
1131 struct mbuf *m;
1132 int nack;
1133 int i;
1134
1135 /* Verify peer's ACK is in range */
1136 if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0)
1137 return; /* duplicate ack */
1138 if (L2TP_SEQ_DIFF(nr, seq->ns) > 0) {
1139 priv->stats.recvBadAcks++; /* ack for packet not sent */
1140 return;
1141 }
1142 KASSERT(nack <= L2TP_MAX_XWIN,
1143 ("%s: nack=%d > %d", __func__, nack, L2TP_MAX_XWIN));
1144
1145 /* Update receive ack stats */
1146 seq->rack = nr;
1147 seq->rexmits = 0;
1148
1149 /* Free acknowledged packets and shift up packets in the xmit queue */
1150 for (i = 0; i < nack; i++)
1151 m_freem(seq->xwin[i]);
1152 memmove(seq->xwin, seq->xwin + nack,
1153 (L2TP_MAX_XWIN - nack) * sizeof(*seq->xwin));
1154 memset(seq->xwin + (L2TP_MAX_XWIN - nack), 0,
1155 nack * sizeof(*seq->xwin));
1156
1157 /*
1158 * Do slow-start/congestion avoidance windowing algorithm described
1159 * in RFC 2661, Appendix A. Here we handle a multiple ACK as if each
1160 * ACK had arrived separately.
1161 */
1162 if (seq->cwnd < seq->wmax) {
1163
1164 /* Handle slow start phase */
1165 if (seq->cwnd < seq->ssth) {
1166 seq->cwnd += nack;
1167 nack = 0;
1168 if (seq->cwnd > seq->ssth) { /* into cg.av. phase */
1169 nack = seq->cwnd - seq->ssth;
1170 seq->cwnd = seq->ssth;
1171 }
1172 }
1173
1174 /* Handle congestion avoidance phase */
1175 if (seq->cwnd >= seq->ssth) {
1176 seq->acks += nack;
1177 while (seq->acks >= seq->cwnd) {
1178 seq->acks -= seq->cwnd;
1179 if (seq->cwnd < seq->wmax)
1180 seq->cwnd++;
1181 }
1182 }
1183 }
1184
1185 /* Stop xmit timer */
1186 if (seq->rack_timer_running && callout_stop(&seq->rack_timer) == 1) {
1187 seq->rack_timer_running = 0;
1188 NG_NODE_UNREF(priv->node);
1189 }
1190
1191 /* If transmit queue is empty, we're done for now */
1192 if (seq->xwin[0] == NULL)
1193 return;
1194
1195 /* Start restransmit timer again */
1196 callout_reset(&seq->rack_timer,
1197 hz, ng_l2tp_seq_rack_timeout, priv->node);
1198 seq->rack_timer_running = 1;
1199 NG_NODE_REF(priv->node);
1200
1201 /*
1202 * Send more packets, trying to keep peer's receive window full.
1203 * If there is a memory error, pretend packet was sent, as it
1204 * will get retransmitted later anyway.
1205 */
1206 while ((i = L2TP_SEQ_DIFF(seq->ns, seq->rack)) < seq->cwnd
1207 && seq->xwin[i] != NULL) {
1208 if ((m = L2TP_COPY_MBUF(seq->xwin[i], MB_DONTWAIT)) == NULL)
1209 priv->stats.memoryFailures++;
1210 else
1211 ng_l2tp_xmit_ctrl(priv, m, seq->ns);
1212 seq->ns++;
1213 }
1214 }
1215
1216 /*
1217 * Handle receipt of a sequence number value (Ns) from peer.
1218 * We make no attempt to re-order out of order packets.
1219 *
1220 * This function should only be called for non-ZLB packets.
1221 *
1222 * Returns:
1223 * 0 Accept packet
1224 * -1 Drop packet
1225 */
1226 static int
1227 ng_l2tp_seq_recv_ns(priv_p priv, u_int16_t ns)
1228 {
1229 struct l2tp_seq *const seq = &priv->seq;
1230
1231 /* If not what we expect, drop packet and send an immediate ZLB ack */
1232 if (ns != seq->nr) {
1233 if (L2TP_SEQ_DIFF(ns, seq->nr) < 0)
1234 priv->stats.recvDuplicates++;
1235 else
1236 priv->stats.recvOutOfOrder++;
1237 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
1238 return (-1);
1239 }
1240
1241 /* Update recv sequence number */
1242 seq->nr++;
1243
1244 /* Start receive ack timer, if not already running */
1245 if (!seq->xack_timer_running) {
1246 callout_reset(&seq->xack_timer,
1247 L2TP_DELAYED_ACK, ng_l2tp_seq_xack_timeout, priv->node);
1248 seq->xack_timer_running = 1;
1249 NG_NODE_REF(priv->node);
1250 }
1251
1252 /* Accept packet */
1253 return (0);
1254 }
1255
1256 /*
1257 * Handle an ack timeout. We have an outstanding ack that we
1258 * were hoping to piggy-back, but haven't, so send a ZLB.
1259 */
1260 static void
1261 ng_l2tp_seq_xack_timeout(void *arg)
1262 {
1263 const node_p node = arg;
1264 const priv_p priv = NG_NODE_PRIVATE(node);
1265 struct l2tp_seq *const seq = &priv->seq;
1266
1267 /* Check if node is going away */
1268 crit_enter();
1269 if (NG_NODE_NOT_VALID(node)) {
1270 seq->xack_timer_running = 0;
1271 if (!seq->rack_timer_running) {
1272 if (priv->ftarget != NULL)
1273 FREE(priv->ftarget, M_NETGRAPH_L2TP);
1274 FREE(priv, M_NETGRAPH_L2TP);
1275 NG_NODE_SET_PRIVATE(node, NULL);
1276 }
1277 NG_NODE_UNREF(node);
1278 crit_exit();
1279 return;
1280 }
1281
1282 /* Sanity check */
1283 L2TP_SEQ_CHECK(seq);
1284
1285 /* If ack is still outstanding, send a ZLB */
1286 if (seq->xack != seq->nr)
1287 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
1288
1289 /* Done */
1290 seq->xack_timer_running = 0;
1291 NG_NODE_UNREF(node);
1292 L2TP_SEQ_CHECK(seq);
1293 crit_exit();
1294 }
1295
1296 /*
1297 * Handle a transmit timeout. The peer has failed to respond
1298 * with an ack for our packet, so retransmit it.
1299 */
1300 static void
1301 ng_l2tp_seq_rack_timeout(void *arg)
1302 {
1303 const node_p node = arg;
1304 const priv_p priv = NG_NODE_PRIVATE(node);
1305 struct l2tp_seq *const seq = &priv->seq;
1306 struct mbuf *m;
1307 u_int delay;
1308
1309 /* Check if node is going away */
1310 crit_enter();
1311 if (NG_NODE_NOT_VALID(node)) {
1312 seq->rack_timer_running = 0;
1313 if (!seq->xack_timer_running) {
1314 if (priv->ftarget != NULL)
1315 FREE(priv->ftarget, M_NETGRAPH_L2TP);
1316 FREE(priv, M_NETGRAPH_L2TP);
1317 NG_NODE_SET_PRIVATE(node, NULL);
1318 }
1319 NG_NODE_UNREF(node);
1320 crit_exit();
1321 return;
1322 }
1323
1324 /* Sanity check */
1325 L2TP_SEQ_CHECK(seq);
1326
1327 /* Make sure peer's ack is still outstanding before doing anything */
1328 if (seq->rack == seq->ns) {
1329 seq->rack_timer_running = 0;
1330 NG_NODE_UNREF(node);
1331 goto done;
1332 }
1333 priv->stats.xmitRetransmits++;
1334
1335 /* Have we reached the retransmit limit? If so, notify owner. */
1336 if (seq->rexmits++ >= seq->max_rexmits)
1337 ng_l2tp_seq_failure(priv);
1338
1339 /* Restart timer, this time with an increased delay */
1340 delay = (seq->rexmits > 12) ? (1 << 12) : (1 << seq->rexmits);
1341 if (delay > seq->max_rexmit_to)
1342 delay = seq->max_rexmit_to;
1343 callout_reset(&seq->rack_timer,
1344 hz * delay, ng_l2tp_seq_rack_timeout, node);
1345
1346 /* Do slow-start/congestion algorithm windowing algorithm */
1347 seq->ssth = (seq->cwnd + 1) / 2;
1348 seq->cwnd = 1;
1349 seq->acks = 0;
1350
1351 /* Retransmit oldest unack'd packet */
1352 if ((m = L2TP_COPY_MBUF(seq->xwin[0], MB_DONTWAIT)) == NULL)
1353 priv->stats.memoryFailures++;
1354 else
1355 ng_l2tp_xmit_ctrl(priv, m, seq->rack);
1356
1357 done:
1358 /* Done */
1359 L2TP_SEQ_CHECK(seq);
1360 crit_exit();
1361 }
1362
1363 /*
1364 * Transmit a control stream packet, payload optional.
1365 * The transmit sequence number is not incremented.
1366 */
1367 static int
1368 ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns)
1369 {
1370 struct l2tp_seq *const seq = &priv->seq;
1371 u_int16_t session_id = 0;
1372 meta_p meta = NULL;
1373 int error;
1374
1375 /* If no mbuf passed, send an empty packet (ZLB) */
1376 if (m == NULL) {
1377
1378 /* Create a new mbuf for ZLB packet */
1379 MGETHDR(m, MB_DONTWAIT, MT_DATA);
1380 if (m == NULL) {
1381 priv->stats.memoryFailures++;
1382 return (ENOBUFS);
1383 }
1384 m->m_len = m->m_pkthdr.len = 12;
1385 m->m_pkthdr.rcvif = NULL;
1386 priv->stats.xmitZLBs++;
1387 } else {
1388
1389 /* Strip off session ID */
1390 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
1391 priv->stats.memoryFailures++;
1392 return (ENOBUFS);
1393 }
1394 memcpy(&session_id, mtod(m, u_int16_t *), 2);
1395 m_adj(m, 2);
1396
1397 /* Make room for L2TP header */
1398 M_PREPEND(m, 12, MB_DONTWAIT);
1399 if (m == NULL) {
1400 priv->stats.memoryFailures++;
1401 return (ENOBUFS);
1402 }
1403 }
1404
1405 /* Fill in L2TP header */
1406 mtod(m, u_int16_t *)[0] = htons(L2TP_CTRL_HDR);
1407 mtod(m, u_int16_t *)[1] = htons(m->m_pkthdr.len);
1408 mtod(m, u_int16_t *)[2] = priv->conf.peer_id;
1409 mtod(m, u_int16_t *)[3] = session_id;
1410 mtod(m, u_int16_t *)[4] = htons(ns);
1411 mtod(m, u_int16_t *)[5] = htons(seq->nr);
1412
1413 /* Update sequence number info and stats */
1414 priv->stats.xmitPackets++;
1415 priv->stats.xmitOctets += m->m_pkthdr.len;
1416
1417 /* Stop ack timer: we're sending an ack with this packet */
1418 if (seq->xack_timer_running && callout_stop(&seq->xack_timer) == 1) {
1419 seq->xack_timer_running = 0;
1420 NG_NODE_UNREF(priv->node);
1421 }
1422 seq->xack = seq->nr;
1423
1424 /* Send packet */
1425 NG_SEND_DATA(error, priv->lower, m, meta);
1426 return (error);
1427 }
1428
1429 #ifdef INVARIANTS
1430 /*
1431 * Sanity check sequence number state.
1432 */
1433 static void
1434 ng_l2tp_seq_check(struct l2tp_seq *seq)
1435 {
1436 const int self_unack = L2TP_SEQ_DIFF(seq->nr, seq->xack);
1437 const int peer_unack = L2TP_SEQ_DIFF(seq->ns, seq->rack);
1438 int i;
1439
1440 #define CHECK(p) KASSERT((p), ("%s: not: %s", __func__, #p))
1441
1442 CHECK(seq->wmax <= L2TP_MAX_XWIN);
1443 CHECK(seq->cwnd >= 1);
1444 CHECK(seq->cwnd <= seq->wmax);
1445 CHECK(seq->ssth >= 1);
1446 CHECK(seq->ssth <= seq->wmax);
1447 if (seq->cwnd < seq->ssth)
1448 CHECK(seq->acks == 0);
1449 else
1450 CHECK(seq->acks <= seq->cwnd);
1451 CHECK(self_unack >= 0);
1452 CHECK(peer_unack >= 0);
1453 CHECK(peer_unack <= seq->wmax);
1454 CHECK((self_unack == 0) ^ seq->xack_timer_running);
1455 CHECK((peer_unack == 0) ^ seq->rack_timer_running);
1456 CHECK(seq->rack_timer_running || !callout_pending(&seq->rack_timer));
1457 CHECK(seq->xack_timer_running || !callout_pending(&seq->xack_timer));
1458 for (i = 0; i < peer_unack; i++)
1459 CHECK(seq->xwin[i] != NULL);
1460 for ( ; i < seq->cwnd; i++) /* verify peer's recv window full */
1461 CHECK(seq->xwin[i] == NULL);
1462
1463 #undef CHECK
1464 }
1465 #endif /* INVARIANTS */
1466
1467
DragonFly BSD