kernel/netgraph7: Replace usage of MALLOC/FREE with kmalloc/kfree here too.
[dragonfly.git] / sys / netgraph7 / ng_l2tp.c
CommitLineData
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1/*-
2 * Copyright (c) 2001-2002 Packet Design, LLC.
3 * All rights reserved.
4 *
5 * Subject to the following obligations and disclaimer of warranty,
6 * use and redistribution of this software, in source or object code
7 * forms, with or without modifications are expressly permitted by
8 * Packet Design; provided, however, that:
9 *
10 * (i) Any and all reproductions of the source or object code
11 * must include the copyright notice above and the following
12 * disclaimer of warranties; and
13 * (ii) No rights are granted, in any manner or form, to use
14 * Packet Design trademarks, including the mark "PACKET DESIGN"
15 * on advertising, endorsements, or otherwise except as such
16 * appears in the above copyright notice or in the software.
17 *
18 * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
19 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
20 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
21 * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
22 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
23 * OR NON-INFRINGEMENT. PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
24 * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
25 * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
26 * RELIABILITY OR OTHERWISE. IN NO EVENT SHALL PACKET DESIGN BE
27 * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
28 * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
29 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
30 * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
31 * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY THEORY OF
32 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
34 * THE USE OF THIS SOFTWARE, EVEN IF PACKET DESIGN IS ADVISED OF
35 * THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Author: Archie Cobbs <archie@freebsd.org>
38 *
39 * $FreeBSD: src/sys/netgraph/ng_l2tp.c,v 1.25 2008/03/16 21:33:12 mav Exp $
5a975a3d 40 * $DragonFly: src/sys/netgraph7/ng_l2tp.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
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41 */
42
43/*
44 * L2TP netgraph node type.
45 *
46 * This node type implements the lower layer of the
47 * L2TP protocol as specified in RFC 2661.
48 */
49
50#include <sys/param.h>
51#include <sys/systm.h>
52#include <sys/kernel.h>
53#include <sys/time.h>
54#include <sys/conf.h>
55#include <sys/mbuf.h>
56#include <sys/malloc.h>
57#include <sys/errno.h>
58#include <sys/libkern.h>
59
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60#include "ng_message.h"
61#include "netgraph.h"
62#include "ng_parse.h"
63#include "ng_l2tp.h"
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64
65#ifdef NG_SEPARATE_MALLOC
66MALLOC_DEFINE(M_NETGRAPH_L2TP, "netgraph_l2tp", "netgraph l2tp node");
67#else
68#define M_NETGRAPH_L2TP M_NETGRAPH
69#endif
70
71/* L2TP header format (first 2 bytes only) */
72#define L2TP_HDR_CTRL 0x8000 /* control packet */
73#define L2TP_HDR_LEN 0x4000 /* has length field */
74#define L2TP_HDR_SEQ 0x0800 /* has ns, nr fields */
75#define L2TP_HDR_OFF 0x0200 /* has offset field */
76#define L2TP_HDR_PRIO 0x0100 /* give priority */
77#define L2TP_HDR_VERS_MASK 0x000f /* version field mask */
78#define L2TP_HDR_VERSION 0x0002 /* version field */
79
80/* Bits that must be zero or one in first two bytes of header */
81#define L2TP_CTRL_0BITS 0x030d /* ctrl: must be 0 */
82#define L2TP_CTRL_1BITS 0xc802 /* ctrl: must be 1 */
83#define L2TP_DATA_0BITS 0x800d /* data: must be 0 */
84#define L2TP_DATA_1BITS 0x0002 /* data: must be 1 */
85
86/* Standard xmit ctrl and data header bits */
87#define L2TP_CTRL_HDR (L2TP_HDR_CTRL | L2TP_HDR_LEN \
88 | L2TP_HDR_SEQ | L2TP_HDR_VERSION)
89#define L2TP_DATA_HDR (L2TP_HDR_VERSION) /* optional: len, seq */
90
91/* Some hard coded values */
92#define L2TP_MAX_XWIN 128 /* my max xmit window */
93#define L2TP_MAX_REXMIT 5 /* default max rexmit */
94#define L2TP_MAX_REXMIT_TO 30 /* default rexmit to */
95#define L2TP_DELAYED_ACK ((hz + 19) / 20) /* delayed ack: 50 ms */
96
97/* Default data sequence number configuration for new sessions */
98#define L2TP_CONTROL_DSEQ 1 /* we are the lns */
99#define L2TP_ENABLE_DSEQ 1 /* enable data seq # */
100
101/* Compare sequence numbers using circular math */
102#define L2TP_SEQ_DIFF(x, y) ((int)((int16_t)(x) - (int16_t)(y)))
103
104#define SESSHASHSIZE 0x0020
105#define SESSHASH(x) (((x) ^ ((x) >> 8)) & (SESSHASHSIZE - 1))
106
107/* Hook private data (data session hooks only) */
108struct ng_l2tp_hook_private {
109 struct ng_l2tp_sess_config conf; /* hook/session config */
110 struct ng_l2tp_session_stats stats; /* per sessions statistics */
111 hook_p hook; /* hook reference */
112 u_int16_t ns; /* data ns sequence number */
113 u_int16_t nr; /* data nr sequence number */
114 LIST_ENTRY(ng_l2tp_hook_private) sessions;
115};
116typedef struct ng_l2tp_hook_private *hookpriv_p;
117
118/*
119 * Sequence number state
120 *
121 * Invariants:
122 * - If cwnd < ssth, we're doing slow start, otherwise congestion avoidance
123 * - The number of unacknowledged xmit packets is (ns - rack) <= seq->wmax
124 * - The first (ns - rack) mbuf's in xwin[] array are copies of these
125 * unacknowledged packets; the remainder of xwin[] consists first of
126 * zero or more further untransmitted packets in the transmit queue
127 * - We try to keep the peer's receive window as full as possible.
128 * Therefore, (i < cwnd && xwin[i] != NULL) implies (ns - rack) > i.
129 * - rack_timer is running iff (ns - rack) > 0 (unack'd xmit'd pkts)
130 * - If xack != nr, there are unacknowledged recv packet(s) (delayed ack)
131 * - xack_timer is running iff xack != nr (unack'd rec'd pkts)
132 */
133struct l2tp_seq {
134 u_int16_t ns; /* next xmit seq we send */
135 u_int16_t nr; /* next recv seq we expect */
136 u_int16_t inproc; /* packet is in processing */
137 u_int16_t rack; /* last 'nr' we rec'd */
138 u_int16_t xack; /* last 'nr' we sent */
139 u_int16_t wmax; /* peer's max recv window */
140 u_int16_t cwnd; /* current congestion window */
141 u_int16_t ssth; /* slow start threshold */
142 u_int16_t acks; /* # consecutive acks rec'd */
143 u_int16_t rexmits; /* # retransmits sent */
144 struct callout rack_timer; /* retransmit timer */
145 struct callout xack_timer; /* delayed ack timer */
146 struct mbuf *xwin[L2TP_MAX_XWIN]; /* transmit window */
147 struct mtx mtx; /* seq mutex */
148};
149
150/* Node private data */
151struct ng_l2tp_private {
152 node_p node; /* back pointer to node */
153 hook_p ctrl; /* hook to upper layers */
154 hook_p lower; /* hook to lower layers */
155 struct ng_l2tp_config conf; /* node configuration */
156 struct ng_l2tp_stats stats; /* node statistics */
157 struct l2tp_seq seq; /* ctrl sequence number state */
158 ng_ID_t ftarget; /* failure message target */
159 LIST_HEAD(, ng_l2tp_hook_private) sesshash[SESSHASHSIZE];
160};
161typedef struct ng_l2tp_private *priv_p;
162
163/* Netgraph node methods */
164static ng_constructor_t ng_l2tp_constructor;
165static ng_rcvmsg_t ng_l2tp_rcvmsg;
166static ng_shutdown_t ng_l2tp_shutdown;
167static ng_newhook_t ng_l2tp_newhook;
168static ng_rcvdata_t ng_l2tp_rcvdata;
169static ng_rcvdata_t ng_l2tp_rcvdata_lower;
170static ng_rcvdata_t ng_l2tp_rcvdata_ctrl;
171static ng_disconnect_t ng_l2tp_disconnect;
172
173/* Internal functions */
174static int ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns);
175
176static void ng_l2tp_seq_init(priv_p priv);
177static int ng_l2tp_seq_set(priv_p priv,
178 const struct ng_l2tp_seq_config *conf);
179static int ng_l2tp_seq_adjust(priv_p priv,
180 const struct ng_l2tp_config *conf);
181static void ng_l2tp_seq_reset(priv_p priv);
182static void ng_l2tp_seq_failure(priv_p priv);
183static void ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr);
184static void ng_l2tp_seq_xack_timeout(node_p node, hook_p hook,
185 void *arg1, int arg2);
186static void ng_l2tp_seq_rack_timeout(node_p node, hook_p hook,
187 void *arg1, int arg2);
188
189static hookpriv_p ng_l2tp_find_session(priv_p privp, u_int16_t sid);
190static ng_fn_eachhook ng_l2tp_reset_session;
191
192#ifdef INVARIANTS
193static void ng_l2tp_seq_check(struct l2tp_seq *seq);
194#endif
195
196/* Parse type for struct ng_l2tp_seq_config. */
197static const struct ng_parse_struct_field
198 ng_l2tp_seq_config_fields[] = NG_L2TP_SEQ_CONFIG_TYPE_INFO;
199static const struct ng_parse_type ng_l2tp_seq_config_type = {
200 &ng_parse_struct_type,
201 &ng_l2tp_seq_config_fields
202};
203
204/* Parse type for struct ng_l2tp_config */
205static const struct ng_parse_struct_field
206 ng_l2tp_config_type_fields[] = NG_L2TP_CONFIG_TYPE_INFO;
207static const struct ng_parse_type ng_l2tp_config_type = {
208 &ng_parse_struct_type,
209 &ng_l2tp_config_type_fields,
210};
211
212/* Parse type for struct ng_l2tp_sess_config */
213static const struct ng_parse_struct_field
214 ng_l2tp_sess_config_type_fields[] = NG_L2TP_SESS_CONFIG_TYPE_INFO;
215static const struct ng_parse_type ng_l2tp_sess_config_type = {
216 &ng_parse_struct_type,
217 &ng_l2tp_sess_config_type_fields,
218};
219
220/* Parse type for struct ng_l2tp_stats */
221static const struct ng_parse_struct_field
222 ng_l2tp_stats_type_fields[] = NG_L2TP_STATS_TYPE_INFO;
223static const struct ng_parse_type ng_l2tp_stats_type = {
224 &ng_parse_struct_type,
225 &ng_l2tp_stats_type_fields
226};
227
228/* Parse type for struct ng_l2tp_session_stats. */
229static const struct ng_parse_struct_field
230 ng_l2tp_session_stats_type_fields[] = NG_L2TP_SESSION_STATS_TYPE_INFO;
231static const struct ng_parse_type ng_l2tp_session_stats_type = {
232 &ng_parse_struct_type,
233 &ng_l2tp_session_stats_type_fields
234};
235
236/* List of commands and how to convert arguments to/from ASCII */
237static const struct ng_cmdlist ng_l2tp_cmdlist[] = {
238 {
239 NGM_L2TP_COOKIE,
240 NGM_L2TP_SET_CONFIG,
241 "setconfig",
242 &ng_l2tp_config_type,
243 NULL
244 },
245 {
246 NGM_L2TP_COOKIE,
247 NGM_L2TP_GET_CONFIG,
248 "getconfig",
249 NULL,
250 &ng_l2tp_config_type
251 },
252 {
253 NGM_L2TP_COOKIE,
254 NGM_L2TP_SET_SESS_CONFIG,
255 "setsessconfig",
256 &ng_l2tp_sess_config_type,
257 NULL
258 },
259 {
260 NGM_L2TP_COOKIE,
261 NGM_L2TP_GET_SESS_CONFIG,
262 "getsessconfig",
263 &ng_parse_hint16_type,
264 &ng_l2tp_sess_config_type
265 },
266 {
267 NGM_L2TP_COOKIE,
268 NGM_L2TP_GET_STATS,
269 "getstats",
270 NULL,
271 &ng_l2tp_stats_type
272 },
273 {
274 NGM_L2TP_COOKIE,
275 NGM_L2TP_CLR_STATS,
276 "clrstats",
277 NULL,
278 NULL
279 },
280 {
281 NGM_L2TP_COOKIE,
282 NGM_L2TP_GETCLR_STATS,
283 "getclrstats",
284 NULL,
285 &ng_l2tp_stats_type
286 },
287 {
288 NGM_L2TP_COOKIE,
289 NGM_L2TP_GET_SESSION_STATS,
290 "getsessstats",
291 &ng_parse_int16_type,
292 &ng_l2tp_session_stats_type
293 },
294 {
295 NGM_L2TP_COOKIE,
296 NGM_L2TP_CLR_SESSION_STATS,
297 "clrsessstats",
298 &ng_parse_int16_type,
299 NULL
300 },
301 {
302 NGM_L2TP_COOKIE,
303 NGM_L2TP_GETCLR_SESSION_STATS,
304 "getclrsessstats",
305 &ng_parse_int16_type,
306 &ng_l2tp_session_stats_type
307 },
308 {
309 NGM_L2TP_COOKIE,
310 NGM_L2TP_ACK_FAILURE,
311 "ackfailure",
312 NULL,
313 NULL
314 },
315 {
316 NGM_L2TP_COOKIE,
317 NGM_L2TP_SET_SEQ,
318 "setsequence",
319 &ng_l2tp_seq_config_type,
320 NULL
321 },
322 { 0 }
323};
324
325/* Node type descriptor */
326static struct ng_type ng_l2tp_typestruct = {
327 .version = NG_ABI_VERSION,
328 .name = NG_L2TP_NODE_TYPE,
329 .constructor = ng_l2tp_constructor,
330 .rcvmsg = ng_l2tp_rcvmsg,
331 .shutdown = ng_l2tp_shutdown,
332 .newhook = ng_l2tp_newhook,
333 .rcvdata = ng_l2tp_rcvdata,
334 .disconnect = ng_l2tp_disconnect,
335 .cmdlist = ng_l2tp_cmdlist,
336};
337NETGRAPH_INIT(l2tp, &ng_l2tp_typestruct);
338
339/* Sequence number state sanity checking */
340#ifdef INVARIANTS
341#define L2TP_SEQ_CHECK(seq) ng_l2tp_seq_check(seq)
342#else
343#define L2TP_SEQ_CHECK(x) do { } while (0)
344#endif
345
346/* memmove macro */
347#define memmove(d, s, l) bcopy(s, d, l)
348
349/* Whether to use m_copypacket() or m_dup() */
350#define L2TP_COPY_MBUF m_copypacket
351
352#define ERROUT(x) do { error = (x); goto done; } while (0)
353
354/************************************************************************
355 NETGRAPH NODE STUFF
356************************************************************************/
357
358/*
359 * Node type constructor
360 */
361static int
362ng_l2tp_constructor(node_p node)
363{
364 priv_p priv;
365 int i;
366
367 /* Allocate private structure */
fc025606
SW
368 priv = kmalloc(sizeof(*priv), M_NETGRAPH_L2TP,
369 M_WAITOK | M_NULLOK | M_ZERO);
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370 if (priv == NULL)
371 return (ENOMEM);
372 NG_NODE_SET_PRIVATE(node, priv);
373 priv->node = node;
374
375 /* Apply a semi-reasonable default configuration */
376 priv->conf.peer_win = 1;
377 priv->conf.rexmit_max = L2TP_MAX_REXMIT;
378 priv->conf.rexmit_max_to = L2TP_MAX_REXMIT_TO;
379
380 /* Initialize sequence number state */
381 ng_l2tp_seq_init(priv);
382
383 for (i = 0; i < SESSHASHSIZE; i++)
384 LIST_INIT(&priv->sesshash[i]);
385
386 /* Done */
387 return (0);
388}
389
390/*
391 * Give our OK for a hook to be added.
392 */
393static int
394ng_l2tp_newhook(node_p node, hook_p hook, const char *name)
395{
396 const priv_p priv = NG_NODE_PRIVATE(node);
397
398 /* Check hook name */
399 if (strcmp(name, NG_L2TP_HOOK_CTRL) == 0) {
400 if (priv->ctrl != NULL)
401 return (EISCONN);
402 priv->ctrl = hook;
403 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_ctrl);
404 } else if (strcmp(name, NG_L2TP_HOOK_LOWER) == 0) {
405 if (priv->lower != NULL)
406 return (EISCONN);
407 priv->lower = hook;
408 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_lower);
409 } else {
410 static const char hexdig[16] = "0123456789abcdef";
411 u_int16_t session_id;
412 hookpriv_p hpriv;
413 uint16_t hash;
414 const char *hex;
415 int i;
416 int j;
417
418 /* Parse hook name to get session ID */
419 if (strncmp(name, NG_L2TP_HOOK_SESSION_P,
420 sizeof(NG_L2TP_HOOK_SESSION_P) - 1) != 0)
421 return (EINVAL);
422 hex = name + sizeof(NG_L2TP_HOOK_SESSION_P) - 1;
423 for (session_id = i = 0; i < 4; i++) {
424 for (j = 0; j < 16 && hex[i] != hexdig[j]; j++);
425 if (j == 16)
426 return (EINVAL);
427 session_id = (session_id << 4) | j;
428 }
429 if (hex[i] != '\0')
430 return (EINVAL);
431
432 /* Create hook private structure */
fc025606
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433 hpriv = kmalloc(sizeof(*hpriv), M_NETGRAPH_L2TP,
434 M_WAITOK | M_NULLOK | M_ZERO);
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435 if (hpriv == NULL)
436 return (ENOMEM);
437 hpriv->conf.session_id = htons(session_id);
438 hpriv->conf.control_dseq = L2TP_CONTROL_DSEQ;
439 hpriv->conf.enable_dseq = L2TP_ENABLE_DSEQ;
440 hpriv->hook = hook;
441 NG_HOOK_SET_PRIVATE(hook, hpriv);
442 hash = SESSHASH(hpriv->conf.session_id);
443 LIST_INSERT_HEAD(&priv->sesshash[hash], hpriv, sessions);
444 }
445
446 /* Done */
447 return (0);
448}
449
450/*
451 * Receive a control message.
452 */
453static int
454ng_l2tp_rcvmsg(node_p node, item_p item, hook_p lasthook)
455{
456 const priv_p priv = NG_NODE_PRIVATE(node);
457 struct ng_mesg *resp = NULL;
458 struct ng_mesg *msg;
459 int error = 0;
460
461 NGI_GET_MSG(item, msg);
462 switch (msg->header.typecookie) {
463 case NGM_L2TP_COOKIE:
464 switch (msg->header.cmd) {
465 case NGM_L2TP_SET_CONFIG:
466 {
467 struct ng_l2tp_config *const conf =
468 (struct ng_l2tp_config *)msg->data;
469
470 /* Check for invalid or illegal config */
471 if (msg->header.arglen != sizeof(*conf)) {
472 error = EINVAL;
473 break;
474 }
475 conf->enabled = !!conf->enabled;
476 conf->match_id = !!conf->match_id;
477 conf->tunnel_id = htons(conf->tunnel_id);
478 conf->peer_id = htons(conf->peer_id);
479 if (priv->conf.enabled
480 && ((priv->conf.tunnel_id != 0
481 && conf->tunnel_id != priv->conf.tunnel_id)
482 || ((priv->conf.peer_id != 0
483 && conf->peer_id != priv->conf.peer_id)))) {
484 error = EBUSY;
485 break;
486 }
487
488 /* Save calling node as failure target */
489 priv->ftarget = NGI_RETADDR(item);
490
491 /* Adjust sequence number state */
492 if ((error = ng_l2tp_seq_adjust(priv, conf)) != 0)
493 break;
494
495 /* Update node's config */
496 priv->conf = *conf;
497 break;
498 }
499 case NGM_L2TP_GET_CONFIG:
500 {
501 struct ng_l2tp_config *conf;
502
5a975a3d 503 NG_MKRESPONSE(resp, msg, sizeof(*conf), M_WAITOK | M_NULLOK);
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504 if (resp == NULL) {
505 error = ENOMEM;
506 break;
507 }
508 conf = (struct ng_l2tp_config *)resp->data;
509 *conf = priv->conf;
510
511 /* Put ID's in host order */
512 conf->tunnel_id = ntohs(conf->tunnel_id);
513 conf->peer_id = ntohs(conf->peer_id);
514 break;
515 }
516 case NGM_L2TP_SET_SESS_CONFIG:
517 {
518 struct ng_l2tp_sess_config *const conf =
519 (struct ng_l2tp_sess_config *)msg->data;
520 hookpriv_p hpriv;
521
522 /* Check for invalid or illegal config. */
523 if (msg->header.arglen != sizeof(*conf)) {
524 error = EINVAL;
525 break;
526 }
527
528 /* Put ID's in network order */
529 conf->session_id = htons(conf->session_id);
530 conf->peer_id = htons(conf->peer_id);
531
532 /* Find matching hook */
533 hpriv = ng_l2tp_find_session(priv, conf->session_id);
534 if (hpriv == NULL) {
535 error = ENOENT;
536 break;
537 }
538
539 /* Update hook's config */
540 hpriv->conf = *conf;
541 break;
542 }
543 case NGM_L2TP_GET_SESS_CONFIG:
544 {
545 struct ng_l2tp_sess_config *conf;
546 u_int16_t session_id;
547 hookpriv_p hpriv;
548
549 /* Get session ID */
550 if (msg->header.arglen != sizeof(session_id)) {
551 error = EINVAL;
552 break;
553 }
554 memcpy(&session_id, msg->data, 2);
555 session_id = htons(session_id);
556
557 /* Find matching hook */
558 hpriv = ng_l2tp_find_session(priv, session_id);
559 if (hpriv == NULL) {
560 error = ENOENT;
561 break;
562 }
563
564 /* Send response */
5a975a3d 565 NG_MKRESPONSE(resp, msg, sizeof(hpriv->conf), M_WAITOK | M_NULLOK);
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566 if (resp == NULL) {
567 error = ENOMEM;
568 break;
569 }
570 conf = (struct ng_l2tp_sess_config *)resp->data;
571 *conf = hpriv->conf;
572
573 /* Put ID's in host order */
574 conf->session_id = ntohs(conf->session_id);
575 conf->peer_id = ntohs(conf->peer_id);
576 break;
577 }
578 case NGM_L2TP_GET_STATS:
579 case NGM_L2TP_CLR_STATS:
580 case NGM_L2TP_GETCLR_STATS:
581 {
582 if (msg->header.cmd != NGM_L2TP_CLR_STATS) {
583 NG_MKRESPONSE(resp, msg,
5a975a3d 584 sizeof(priv->stats), M_WAITOK | M_NULLOK);
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585 if (resp == NULL) {
586 error = ENOMEM;
587 break;
588 }
589 memcpy(resp->data,
590 &priv->stats, sizeof(priv->stats));
591 }
592 if (msg->header.cmd != NGM_L2TP_GET_STATS)
593 memset(&priv->stats, 0, sizeof(priv->stats));
594 break;
595 }
596 case NGM_L2TP_GET_SESSION_STATS:
597 case NGM_L2TP_CLR_SESSION_STATS:
598 case NGM_L2TP_GETCLR_SESSION_STATS:
599 {
600 uint16_t session_id;
601 hookpriv_p hpriv;
602
603 /* Get session ID. */
604 if (msg->header.arglen != sizeof(session_id)) {
605 error = EINVAL;
606 break;
607 }
608 bcopy(msg->data, &session_id, sizeof(uint16_t));
609 session_id = htons(session_id);
610
611 /* Find matching hook. */
612 hpriv = ng_l2tp_find_session(priv, session_id);
613 if (hpriv == NULL) {
614 error = ENOENT;
615 break;
616 }
617
618 if (msg->header.cmd != NGM_L2TP_CLR_SESSION_STATS) {
619 NG_MKRESPONSE(resp, msg,
5a975a3d 620 sizeof(hpriv->stats), M_WAITOK | M_NULLOK);
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621 if (resp == NULL) {
622 error = ENOMEM;
623 break;
624 }
625 bcopy(&hpriv->stats, resp->data,
626 sizeof(hpriv->stats));
627 }
628 if (msg->header.cmd != NGM_L2TP_GET_SESSION_STATS)
629 bzero(&hpriv->stats, sizeof(hpriv->stats));
630 break;
631 }
632 case NGM_L2TP_SET_SEQ:
633 {
634 struct ng_l2tp_seq_config *const conf =
635 (struct ng_l2tp_seq_config *)msg->data;
636
637 /* Check for invalid or illegal seq config. */
638 if (msg->header.arglen != sizeof(*conf)) {
639 error = EINVAL;
640 break;
641 }
642 conf->ns = htons(conf->ns);
643 conf->nr = htons(conf->nr);
644 conf->rack = htons(conf->rack);
645 conf->xack = htons(conf->xack);
646
647 /* Set sequence numbers. */
648 error = ng_l2tp_seq_set(priv, conf);
649 break;
650 }
651 default:
652 error = EINVAL;
653 break;
654 }
655 break;
656 default:
657 error = EINVAL;
658 break;
659 }
660
661 /* Done */
662 NG_RESPOND_MSG(error, node, item, resp);
663 NG_FREE_MSG(msg);
664 return (error);
665}
666
667/*
668 * Destroy node
669 */
670static int
671ng_l2tp_shutdown(node_p node)
672{
673 const priv_p priv = NG_NODE_PRIVATE(node);
674 struct l2tp_seq *const seq = &priv->seq;
675
676 /* Sanity check */
677 L2TP_SEQ_CHECK(seq);
678
679 /* Reset sequence number state */
680 ng_l2tp_seq_reset(priv);
681
682 /* Free private data if neither timer is running */
683 ng_uncallout(&seq->rack_timer, node);
684 ng_uncallout(&seq->xack_timer, node);
685
686 mtx_destroy(&seq->mtx);
687
fc025606 688 kfree(priv, M_NETGRAPH_L2TP);
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689
690 /* Unref node */
691 NG_NODE_UNREF(node);
692 return (0);
693}
694
695/*
696 * Hook disconnection
697 */
698static int
699ng_l2tp_disconnect(hook_p hook)
700{
701 const node_p node = NG_HOOK_NODE(hook);
702 const priv_p priv = NG_NODE_PRIVATE(node);
703
704 /* Zero out hook pointer */
705 if (hook == priv->ctrl)
706 priv->ctrl = NULL;
707 else if (hook == priv->lower)
708 priv->lower = NULL;
709 else {
710 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
711 LIST_REMOVE(hpriv, sessions);
fc025606 712 kfree(hpriv, M_NETGRAPH_L2TP);
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713 NG_HOOK_SET_PRIVATE(hook, NULL);
714 }
715
716 /* Go away if no longer connected to anything */
717 if (NG_NODE_NUMHOOKS(node) == 0 && NG_NODE_IS_VALID(node))
718 ng_rmnode_self(node);
719 return (0);
720}
721
722/*************************************************************************
723 INTERNAL FUNCTIONS
724*************************************************************************/
725
726/*
727 * Find the hook with a given session ID (in network order).
728 */
729static hookpriv_p
730ng_l2tp_find_session(priv_p privp, u_int16_t sid)
731{
732 uint16_t hash = SESSHASH(sid);
733 hookpriv_p hpriv = NULL;
734
735 LIST_FOREACH(hpriv, &privp->sesshash[hash], sessions) {
736 if (hpriv->conf.session_id == sid)
737 break;
738 }
739
740 return (hpriv);
741}
742
743/*
744 * Reset a hook's session state.
745 */
746static int
747ng_l2tp_reset_session(hook_p hook, void *arg)
748{
749 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
750
751 if (hpriv != NULL) {
752 hpriv->conf.control_dseq = 0;
753 hpriv->conf.enable_dseq = 0;
754 bzero(&hpriv->conf, sizeof(struct ng_l2tp_session_stats));
755 hpriv->nr = 0;
756 hpriv->ns = 0;
757 }
758 return (-1);
759}
760
761/*
762 * Handle an incoming frame from below.
763 */
764static int
765ng_l2tp_rcvdata_lower(hook_p h, item_p item)
766{
767 static const u_int16_t req_bits[2][2] = {
768 { L2TP_DATA_0BITS, L2TP_DATA_1BITS },
769 { L2TP_CTRL_0BITS, L2TP_CTRL_1BITS },
770 };
771 const node_p node = NG_HOOK_NODE(h);
772 const priv_p priv = NG_NODE_PRIVATE(node);
773 hookpriv_p hpriv = NULL;
774 hook_p hook = NULL;
775 u_int16_t ids[2];
776 struct mbuf *m;
777 u_int16_t hdr;
778 u_int16_t ns;
779 u_int16_t nr;
780 int is_ctrl;
781 int error;
782 int len, plen;
783
784 /* Sanity check */
785 L2TP_SEQ_CHECK(&priv->seq);
786
787 /* If not configured, reject */
788 if (!priv->conf.enabled) {
789 NG_FREE_ITEM(item);
790 ERROUT(ENXIO);
791 }
792
793 /* Grab mbuf */
794 NGI_GET_M(item, m);
795
796 /* Remember full packet length; needed for per session accounting. */
797 plen = m->m_pkthdr.len;
798
799 /* Update stats */
800 priv->stats.recvPackets++;
801 priv->stats.recvOctets += plen;
802
803 /* Get initial header */
804 if (m->m_pkthdr.len < 6) {
805 priv->stats.recvRunts++;
806 NG_FREE_ITEM(item);
807 NG_FREE_M(m);
808 ERROUT(EINVAL);
809 }
810 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
811 priv->stats.memoryFailures++;
812 NG_FREE_ITEM(item);
813 ERROUT(EINVAL);
814 }
815 hdr = ntohs(*mtod(m, u_int16_t *));
816 m_adj(m, 2);
817
818 /* Check required header bits and minimum length */
819 is_ctrl = (hdr & L2TP_HDR_CTRL) != 0;
820 if ((hdr & req_bits[is_ctrl][0]) != 0
821 || (~hdr & req_bits[is_ctrl][1]) != 0) {
822 priv->stats.recvInvalid++;
823 NG_FREE_ITEM(item);
824 NG_FREE_M(m);
825 ERROUT(EINVAL);
826 }
827 if (m->m_pkthdr.len < 4 /* tunnel, session id */
828 + (2 * ((hdr & L2TP_HDR_LEN) != 0)) /* length field */
829 + (4 * ((hdr & L2TP_HDR_SEQ) != 0)) /* seq # fields */
830 + (2 * ((hdr & L2TP_HDR_OFF) != 0))) { /* offset field */
831 priv->stats.recvRunts++;
832 NG_FREE_ITEM(item);
833 NG_FREE_M(m);
834 ERROUT(EINVAL);
835 }
836
837 /* Get and validate length field if present */
838 if ((hdr & L2TP_HDR_LEN) != 0) {
839 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
840 priv->stats.memoryFailures++;
841 NG_FREE_ITEM(item);
842 ERROUT(EINVAL);
843 }
844 len = (u_int16_t)ntohs(*mtod(m, u_int16_t *)) - 4;
845 m_adj(m, 2);
846 if (len < 0 || len > m->m_pkthdr.len) {
847 priv->stats.recvInvalid++;
848 NG_FREE_ITEM(item);
849 NG_FREE_M(m);
850 ERROUT(EINVAL);
851 }
852 if (len < m->m_pkthdr.len) /* trim extra bytes */
853 m_adj(m, -(m->m_pkthdr.len - len));
854 }
855
856 /* Get tunnel ID and session ID */
857 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
858 priv->stats.memoryFailures++;
859 NG_FREE_ITEM(item);
860 ERROUT(EINVAL);
861 }
862 memcpy(ids, mtod(m, u_int16_t *), 4);
863 m_adj(m, 4);
864
865 /* Check tunnel ID */
866 if (ids[0] != priv->conf.tunnel_id
867 && (priv->conf.match_id || ids[0] != 0)) {
868 priv->stats.recvWrongTunnel++;
869 NG_FREE_ITEM(item);
870 NG_FREE_M(m);
871 ERROUT(EADDRNOTAVAIL);
872 }
873
874 /* Check session ID (for data packets only) */
875 if ((hdr & L2TP_HDR_CTRL) == 0) {
876 hpriv = ng_l2tp_find_session(priv, ids[1]);
877 if (hpriv == NULL) {
878 priv->stats.recvUnknownSID++;
879 NG_FREE_ITEM(item);
880 NG_FREE_M(m);
881 ERROUT(ENOTCONN);
882 }
883 hook = hpriv->hook;
884 }
885
886 /* Get Ns, Nr fields if present */
887 if ((hdr & L2TP_HDR_SEQ) != 0) {
888 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) {
889 priv->stats.memoryFailures++;
890 NG_FREE_ITEM(item);
891 ERROUT(EINVAL);
892 }
893 memcpy(&ns, &mtod(m, u_int16_t *)[0], 2);
894 ns = ntohs(ns);
895 memcpy(&nr, &mtod(m, u_int16_t *)[1], 2);
896 nr = ntohs(nr);
897 m_adj(m, 4);
898 }
899
900 /* Strip offset padding if present */
901 if ((hdr & L2TP_HDR_OFF) != 0) {
902 u_int16_t offset;
903
904 /* Get length of offset padding */
905 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
906 priv->stats.memoryFailures++;
907 NG_FREE_ITEM(item);
908 ERROUT(EINVAL);
909 }
910 memcpy(&offset, mtod(m, u_int16_t *), 2);
911 offset = ntohs(offset);
912
913 /* Trim offset padding */
914 if ((2+offset) > m->m_pkthdr.len) {
915 priv->stats.recvInvalid++;
916 NG_FREE_ITEM(item);
917 NG_FREE_M(m);
918 ERROUT(EINVAL);
919 }
920 m_adj(m, 2+offset);
921 }
922
923 /* Handle control packets */
924 if ((hdr & L2TP_HDR_CTRL) != 0) {
925 struct l2tp_seq *const seq = &priv->seq;
926
927 /* Handle receive ack sequence number Nr */
928 ng_l2tp_seq_recv_nr(priv, nr);
929
930 /* Discard ZLB packets */
931 if (m->m_pkthdr.len == 0) {
932 priv->stats.recvZLBs++;
933 NG_FREE_ITEM(item);
934 NG_FREE_M(m);
935 ERROUT(0);
936 }
937
938 mtx_lock(&seq->mtx);
939 /*
940 * If not what we expect or we are busy, drop packet and
941 * send an immediate ZLB ack.
942 */
943 if (ns != seq->nr || seq->inproc) {
944 if (L2TP_SEQ_DIFF(ns, seq->nr) <= 0)
945 priv->stats.recvDuplicates++;
946 else
947 priv->stats.recvOutOfOrder++;
948 mtx_unlock(&seq->mtx);
949 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
950 NG_FREE_ITEM(item);
951 NG_FREE_M(m);
952 ERROUT(0);
953 }
954 /*
955 * Until we deliver this packet we can't receive next one as
956 * we have no information for sending ack.
957 */
958 seq->inproc = 1;
959 mtx_unlock(&seq->mtx);
960
961 /* Prepend session ID to packet. */
5a975a3d 962 M_PREPEND(m, 2, MB_DONTWAIT);
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963 if (m == NULL) {
964 seq->inproc = 0;
965 priv->stats.memoryFailures++;
966 NG_FREE_ITEM(item);
967 ERROUT(ENOBUFS);
968 }
969 memcpy(mtod(m, u_int16_t *), &ids[1], 2);
970
971 /* Deliver packet to upper layers */
972 NG_FWD_NEW_DATA(error, item, priv->ctrl, m);
973
974 mtx_lock(&seq->mtx);
975 /* Ready to process next packet. */
976 seq->inproc = 0;
977
978 /* If packet was successfully delivered send ack. */
979 if (error == 0) {
980 /* Update recv sequence number */
981 seq->nr++;
982 /* Start receive ack timer, if not already running */
983 if (!callout_active(&seq->xack_timer)) {
984 ng_callout(&seq->xack_timer, priv->node, NULL,
985 L2TP_DELAYED_ACK, ng_l2tp_seq_xack_timeout,
986 NULL, 0);
987 }
988 }
989 mtx_unlock(&seq->mtx);
990
991 ERROUT(error);
992 }
993
994 /* Per session packet, account it. */
995 hpriv->stats.recvPackets++;
996 hpriv->stats.recvOctets += plen;
997
998 /* Follow peer's lead in data sequencing, if configured to do so */
999 if (!hpriv->conf.control_dseq)
1000 hpriv->conf.enable_dseq = ((hdr & L2TP_HDR_SEQ) != 0);
1001
1002 /* Handle data sequence numbers if present and enabled */
1003 if ((hdr & L2TP_HDR_SEQ) != 0) {
1004 if (hpriv->conf.enable_dseq
1005 && L2TP_SEQ_DIFF(ns, hpriv->nr) < 0) {
1006 NG_FREE_ITEM(item); /* duplicate or out of order */
1007 NG_FREE_M(m);
1008 priv->stats.recvDataDrops++;
1009 ERROUT(0);
1010 }
1011 hpriv->nr = ns + 1;
1012 }
1013
1014 /* Drop empty data packets */
1015 if (m->m_pkthdr.len == 0) {
1016 NG_FREE_ITEM(item);
1017 NG_FREE_M(m);
1018 ERROUT(0);
1019 }
1020
1021 /* Deliver data */
1022 NG_FWD_NEW_DATA(error, item, hook, m);
1023done:
1024 /* Done */
1025 L2TP_SEQ_CHECK(&priv->seq);
1026 return (error);
1027}
1028
1029/*
1030 * Handle an outgoing control frame.
1031 */
1032static int
1033ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item)
1034{
1035 const node_p node = NG_HOOK_NODE(hook);
1036 const priv_p priv = NG_NODE_PRIVATE(node);
1037 struct l2tp_seq *const seq = &priv->seq;
1038 struct mbuf *m;
1039 int error;
1040 int i;
1041 u_int16_t ns;
1042
1043 /* Sanity check */
1044 L2TP_SEQ_CHECK(&priv->seq);
1045
1046 /* If not configured, reject */
1047 if (!priv->conf.enabled) {
1048 NG_FREE_ITEM(item);
1049 ERROUT(ENXIO);
1050 }
1051
1052 /* Grab mbuf and discard other stuff XXX */
1053 NGI_GET_M(item, m);
1054 NG_FREE_ITEM(item);
1055
1056 /* Packet should have session ID prepended */
1057 if (m->m_pkthdr.len < 2) {
1058 priv->stats.xmitInvalid++;
1059 m_freem(m);
1060 ERROUT(EINVAL);
1061 }
1062
1063 /* Check max length */
1064 if (m->m_pkthdr.len >= 0x10000 - 14) {
1065 priv->stats.xmitTooBig++;
1066 m_freem(m);
1067 ERROUT(EOVERFLOW);
1068 }
1069
1070 mtx_lock(&seq->mtx);
1071
1072 /* Find next empty slot in transmit queue */
1073 for (i = 0; i < L2TP_MAX_XWIN && seq->xwin[i] != NULL; i++);
1074 if (i == L2TP_MAX_XWIN) {
1075 mtx_unlock(&seq->mtx);
1076 priv->stats.xmitDrops++;
1077 m_freem(m);
1078 ERROUT(ENOBUFS);
1079 }
1080 seq->xwin[i] = m;
1081
1082 /* If peer's receive window is already full, nothing else to do */
1083 if (i >= seq->cwnd) {
1084 mtx_unlock(&seq->mtx);
1085 ERROUT(0);
1086 }
1087
1088 /* Start retransmit timer if not already running */
1089 if (!callout_active(&seq->rack_timer))
1090 ng_callout(&seq->rack_timer, node, NULL,
1091 hz, ng_l2tp_seq_rack_timeout, NULL, 0);
1092
1093 ns = seq->ns++;
1094
1095 mtx_unlock(&seq->mtx);
1096
1097 /* Copy packet */
5a975a3d 1098 if ((m = L2TP_COPY_MBUF(m, MB_DONTWAIT)) == NULL) {
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1099 priv->stats.memoryFailures++;
1100 ERROUT(ENOBUFS);
1101 }
1102
1103 /* Send packet and increment xmit sequence number */
1104 error = ng_l2tp_xmit_ctrl(priv, m, ns);
1105done:
1106 /* Done */
1107 L2TP_SEQ_CHECK(&priv->seq);
1108 return (error);
1109}
1110
1111/*
1112 * Handle an outgoing data frame.
1113 */
1114static int
1115ng_l2tp_rcvdata(hook_p hook, item_p item)
1116{
1117 const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
1118 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook);
1119 struct mbuf *m;
1120 u_int16_t hdr;
1121 int error;
1122 int i = 1;
1123
1124 /* Sanity check */
1125 L2TP_SEQ_CHECK(&priv->seq);
1126
1127 /* If not configured, reject */
1128 if (!priv->conf.enabled) {
1129 NG_FREE_ITEM(item);
1130 ERROUT(ENXIO);
1131 }
1132
1133 /* Get mbuf */
1134 NGI_GET_M(item, m);
1135
1136 /* Check max length */
1137 if (m->m_pkthdr.len >= 0x10000 - 12) {
1138 priv->stats.xmitDataTooBig++;
1139 NG_FREE_ITEM(item);
1140 NG_FREE_M(m);
1141 ERROUT(EOVERFLOW);
1142 }
1143
1144 /* Prepend L2TP header */
1145 M_PREPEND(m, 6
1146 + (2 * (hpriv->conf.include_length != 0))
1147 + (4 * (hpriv->conf.enable_dseq != 0)),
5a975a3d 1148 MB_DONTWAIT);
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1149 if (m == NULL) {
1150 priv->stats.memoryFailures++;
1151 NG_FREE_ITEM(item);
1152 ERROUT(ENOBUFS);
1153 }
1154 hdr = L2TP_DATA_HDR;
1155 if (hpriv->conf.include_length) {
1156 hdr |= L2TP_HDR_LEN;
1157 mtod(m, u_int16_t *)[i++] = htons(m->m_pkthdr.len);
1158 }
1159 mtod(m, u_int16_t *)[i++] = priv->conf.peer_id;
1160 mtod(m, u_int16_t *)[i++] = hpriv->conf.peer_id;
1161 if (hpriv->conf.enable_dseq) {
1162 hdr |= L2TP_HDR_SEQ;
1163 mtod(m, u_int16_t *)[i++] = htons(hpriv->ns);
1164 mtod(m, u_int16_t *)[i++] = htons(hpriv->nr);
1165 hpriv->ns++;
1166 }
1167 mtod(m, u_int16_t *)[0] = htons(hdr);
1168
1169 /* Update per session stats. */
1170 hpriv->stats.xmitPackets++;
1171 hpriv->stats.xmitOctets += m->m_pkthdr.len;
1172
1173 /* And the global one. */
1174 priv->stats.xmitPackets++;
1175 priv->stats.xmitOctets += m->m_pkthdr.len;
1176
1177 /* Send packet */
1178 NG_FWD_NEW_DATA(error, item, priv->lower, m);
1179done:
1180 /* Done */
1181 L2TP_SEQ_CHECK(&priv->seq);
1182 return (error);
1183}
1184
1185/*
1186 * Send a message to our controlling node that we've failed.
1187 */
1188static void
1189ng_l2tp_seq_failure(priv_p priv)
1190{
1191 struct ng_mesg *msg;
1192 int error;
1193
5a975a3d 1194 NG_MKMESSAGE(msg, NGM_L2TP_COOKIE, NGM_L2TP_ACK_FAILURE, 0, M_WAITOK | M_NULLOK);
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1195 if (msg == NULL)
1196 return;
1197 NG_SEND_MSG_ID(error, priv->node, msg, priv->ftarget, 0);
1198}
1199
1200/************************************************************************
1201 SEQUENCE NUMBER HANDLING
1202************************************************************************/
1203
1204/*
1205 * Initialize sequence number state.
1206 */
1207static void
1208ng_l2tp_seq_init(priv_p priv)
1209{
1210 struct l2tp_seq *const seq = &priv->seq;
1211
1212 KASSERT(priv->conf.peer_win >= 1,
1213 ("%s: peer_win is zero", __func__));
1214 memset(seq, 0, sizeof(*seq));
1215 seq->cwnd = 1;
1216 seq->wmax = priv->conf.peer_win;
1217 if (seq->wmax > L2TP_MAX_XWIN)
1218 seq->wmax = L2TP_MAX_XWIN;
1219 seq->ssth = seq->wmax;
1220 ng_callout_init(&seq->rack_timer);
1221 ng_callout_init(&seq->xack_timer);
1222 mtx_init(&seq->mtx, "ng_l2tp", NULL, MTX_DEF);
1223 L2TP_SEQ_CHECK(seq);
1224}
1225
1226/*
1227 * Set sequence number state as given from user.
1228 */
1229static int
1230ng_l2tp_seq_set(priv_p priv, const struct ng_l2tp_seq_config *conf)
1231{
1232 struct l2tp_seq *const seq = &priv->seq;
1233
1234 /* If node is enabled, deny update to sequence numbers. */
1235 if (priv->conf.enabled)
1236 return (EBUSY);
1237
1238 /* We only can handle the simple cases. */
1239 if (conf->xack != conf->nr || conf->ns != conf->rack)
1240 return (EINVAL);
1241
1242 /* Set ns,nr,rack,xack parameters. */
1243 seq->ns = conf->ns;
1244 seq->nr = conf->nr;
1245 seq->rack = conf->rack;
1246 seq->xack = conf->xack;
1247
1248 return (0);
1249}
1250
1251/*
1252 * Adjust sequence number state accordingly after reconfiguration.
1253 */
1254static int
1255ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf)
1256{
1257 struct l2tp_seq *const seq = &priv->seq;
1258 u_int16_t new_wmax;
1259
1260 /* If disabling node, reset state sequence number */
1261 if (!conf->enabled) {
1262 ng_l2tp_seq_reset(priv);
1263 return (0);
1264 }
1265
1266 /* Adjust peer's max recv window; it can only increase */
1267 new_wmax = conf->peer_win;
1268 if (new_wmax > L2TP_MAX_XWIN)
1269 new_wmax = L2TP_MAX_XWIN;
1270 if (new_wmax == 0)
1271 return (EINVAL);
1272 if (new_wmax < seq->wmax)
1273 return (EBUSY);
1274 seq->wmax = new_wmax;
1275
1276 /* Done */
1277 return (0);
1278}
1279
1280/*
1281 * Reset sequence number state.
1282 */
1283static void
1284ng_l2tp_seq_reset(priv_p priv)
1285{
1286 struct l2tp_seq *const seq = &priv->seq;
1287 hook_p hook;
1288 int i;
1289
1290 /* Sanity check */
1291 L2TP_SEQ_CHECK(seq);
1292
1293 /* Stop timers */
1294 ng_uncallout(&seq->rack_timer, priv->node);
1295 ng_uncallout(&seq->xack_timer, priv->node);
1296
1297 /* Free retransmit queue */
1298 for (i = 0; i < L2TP_MAX_XWIN; i++) {
1299 if (seq->xwin[i] == NULL)
1300 break;
1301 m_freem(seq->xwin[i]);
1302 }
1303
1304 /* Reset session hooks' sequence number states */
1305 NG_NODE_FOREACH_HOOK(priv->node, ng_l2tp_reset_session, NULL, hook);
1306
1307 /* Reset node's sequence number state */
1308 seq->ns = 0;
1309 seq->nr = 0;
1310 seq->rack = 0;
1311 seq->xack = 0;
1312 seq->wmax = L2TP_MAX_XWIN;
1313 seq->cwnd = 1;
1314 seq->ssth = seq->wmax;
1315 seq->acks = 0;
1316 seq->rexmits = 0;
1317 bzero(seq->xwin, sizeof(seq->xwin));
1318
1319 /* Done */
1320 L2TP_SEQ_CHECK(seq);
1321}
1322
1323/*
1324 * Handle receipt of an acknowledgement value (Nr) from peer.
1325 */
1326static void
1327ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr)
1328{
1329 struct l2tp_seq *const seq = &priv->seq;
1330 struct mbuf *xwin[L2TP_MAX_XWIN]; /* partial local copy */
1331 int nack;
1332 int i, j;
1333 uint16_t ns;
1334
1335 mtx_lock(&seq->mtx);
1336
1337 /* Verify peer's ACK is in range */
1338 if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0) {
1339 mtx_unlock(&seq->mtx);
1340 return; /* duplicate ack */
1341 }
1342 if (L2TP_SEQ_DIFF(nr, seq->ns) > 0) {
1343 mtx_unlock(&seq->mtx);
1344 priv->stats.recvBadAcks++; /* ack for packet not sent */
1345 return;
1346 }
1347 KASSERT(nack <= L2TP_MAX_XWIN,
1348 ("%s: nack=%d > %d", __func__, nack, L2TP_MAX_XWIN));
1349
1350 /* Update receive ack stats */
1351 seq->rack = nr;
1352 seq->rexmits = 0;
1353
1354 /* Free acknowledged packets and shift up packets in the xmit queue */
1355 for (i = 0; i < nack; i++)
1356 m_freem(seq->xwin[i]);
1357 memmove(seq->xwin, seq->xwin + nack,
1358 (L2TP_MAX_XWIN - nack) * sizeof(*seq->xwin));
1359 memset(seq->xwin + (L2TP_MAX_XWIN - nack), 0,
1360 nack * sizeof(*seq->xwin));
1361
1362 /*
1363 * Do slow-start/congestion avoidance windowing algorithm described
1364 * in RFC 2661, Appendix A. Here we handle a multiple ACK as if each
1365 * ACK had arrived separately.
1366 */
1367 if (seq->cwnd < seq->wmax) {
1368
1369 /* Handle slow start phase */
1370 if (seq->cwnd < seq->ssth) {
1371 seq->cwnd += nack;
1372 nack = 0;
1373 if (seq->cwnd > seq->ssth) { /* into cg.av. phase */
1374 nack = seq->cwnd - seq->ssth;
1375 seq->cwnd = seq->ssth;
1376 }
1377 }
1378
1379 /* Handle congestion avoidance phase */
1380 if (seq->cwnd >= seq->ssth) {
1381 seq->acks += nack;
1382 while (seq->acks >= seq->cwnd) {
1383 seq->acks -= seq->cwnd;
1384 if (seq->cwnd < seq->wmax)
1385 seq->cwnd++;
1386 }
1387 }
1388 }
1389
1390 /* Stop xmit timer */
1391 if (callout_active(&seq->rack_timer))
1392 ng_uncallout(&seq->rack_timer, priv->node);
1393
1394 /* If transmit queue is empty, we're done for now */
1395 if (seq->xwin[0] == NULL) {
1396 mtx_unlock(&seq->mtx);
1397 return;
1398 }
1399
1400 /* Start restransmit timer again */
1401 ng_callout(&seq->rack_timer, priv->node, NULL,
1402 hz, ng_l2tp_seq_rack_timeout, NULL, 0);
1403
1404 /*
1405 * Send more packets, trying to keep peer's receive window full.
1406 * Make copy of everything we need before lock release.
1407 */
1408 ns = seq->ns;
1409 j = 0;
1410 while ((i = L2TP_SEQ_DIFF(seq->ns, seq->rack)) < seq->cwnd
1411 && seq->xwin[i] != NULL) {
1412 xwin[j++] = seq->xwin[i];
1413 seq->ns++;
1414 }
1415
1416 mtx_unlock(&seq->mtx);
1417
1418 /*
1419 * Send prepared.
1420 * If there is a memory error, pretend packet was sent, as it
1421 * will get retransmitted later anyway.
1422 */
1423 for (i = 0; i < j; i++) {
1424 struct mbuf *m;
5a975a3d 1425 if ((m = L2TP_COPY_MBUF(xwin[i], MB_DONTWAIT)) == NULL)
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1426 priv->stats.memoryFailures++;
1427 else
1428 ng_l2tp_xmit_ctrl(priv, m, ns);
1429 ns++;
1430 }
1431}
1432
1433/*
1434 * Handle an ack timeout. We have an outstanding ack that we
1435 * were hoping to piggy-back, but haven't, so send a ZLB.
1436 */
1437static void
1438ng_l2tp_seq_xack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1439{
1440 const priv_p priv = NG_NODE_PRIVATE(node);
1441 struct l2tp_seq *const seq = &priv->seq;
1442
1443 /* Make sure callout is still active before doing anything */
1444 if (callout_pending(&seq->xack_timer) ||
1445 (!callout_active(&seq->xack_timer)))
1446 return;
1447
1448 /* Sanity check */
1449 L2TP_SEQ_CHECK(seq);
1450
1451 /* Send a ZLB */
1452 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns);
1453
1454 /* callout_deactivate() is not needed here
1455 as ng_uncallout() was called by ng_l2tp_xmit_ctrl() */
1456
1457 /* Sanity check */
1458 L2TP_SEQ_CHECK(seq);
1459}
1460
1461/*
1462 * Handle a transmit timeout. The peer has failed to respond
1463 * with an ack for our packet, so retransmit it.
1464 */
1465static void
1466ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1467{
1468 const priv_p priv = NG_NODE_PRIVATE(node);
1469 struct l2tp_seq *const seq = &priv->seq;
1470 struct mbuf *m;
1471 u_int delay;
1472
1473 /* Make sure callout is still active before doing anything */
1474 if (callout_pending(&seq->rack_timer) ||
1475 (!callout_active(&seq->rack_timer)))
1476 return;
1477
1478 /* Sanity check */
1479 L2TP_SEQ_CHECK(seq);
1480
1481 priv->stats.xmitRetransmits++;
1482
1483 /* Have we reached the retransmit limit? If so, notify owner. */
1484 if (seq->rexmits++ >= priv->conf.rexmit_max)
1485 ng_l2tp_seq_failure(priv);
1486
1487 /* Restart timer, this time with an increased delay */
1488 delay = (seq->rexmits > 12) ? (1 << 12) : (1 << seq->rexmits);
1489 if (delay > priv->conf.rexmit_max_to)
1490 delay = priv->conf.rexmit_max_to;
1491 ng_callout(&seq->rack_timer, node, NULL,
1492 hz * delay, ng_l2tp_seq_rack_timeout, NULL, 0);
1493
1494 /* Do slow-start/congestion algorithm windowing algorithm */
1495 seq->ns = seq->rack;
1496 seq->ssth = (seq->cwnd + 1) / 2;
1497 seq->cwnd = 1;
1498 seq->acks = 0;
1499
1500 /* Retransmit oldest unack'd packet */
5a975a3d 1501 if ((m = L2TP_COPY_MBUF(seq->xwin[0], MB_DONTWAIT)) == NULL)
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1502 priv->stats.memoryFailures++;
1503 else
1504 ng_l2tp_xmit_ctrl(priv, m, seq->ns++);
1505
1506 /* callout_deactivate() is not needed here
1507 as ng_callout() is getting called each time */
1508
1509 /* Sanity check */
1510 L2TP_SEQ_CHECK(seq);
1511}
1512
1513/*
1514 * Transmit a control stream packet, payload optional.
1515 * The transmit sequence number is not incremented.
1516 */
1517static int
1518ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns)
1519{
1520 struct l2tp_seq *const seq = &priv->seq;
1521 u_int16_t session_id = 0;
1522 int error;
1523
1524 mtx_lock(&seq->mtx);
1525
1526 /* Stop ack timer: we're sending an ack with this packet.
1527 Doing this before to keep state predictable after error. */
1528 if (callout_active(&seq->xack_timer))
1529 ng_uncallout(&seq->xack_timer, priv->node);
1530
1531 seq->xack = seq->nr;
1532
1533 mtx_unlock(&seq->mtx);
1534
1535 /* If no mbuf passed, send an empty packet (ZLB) */
1536 if (m == NULL) {
1537
1538 /* Create a new mbuf for ZLB packet */
5a975a3d 1539 MGETHDR(m, MB_DONTWAIT, MT_DATA);
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1540 if (m == NULL) {
1541 priv->stats.memoryFailures++;
1542 return (ENOBUFS);
1543 }
1544 m->m_len = m->m_pkthdr.len = 12;
1545 m->m_pkthdr.rcvif = NULL;
1546 priv->stats.xmitZLBs++;
1547 } else {
1548
1549 /* Strip off session ID */
1550 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) {
1551 priv->stats.memoryFailures++;
1552 return (ENOBUFS);
1553 }
1554 memcpy(&session_id, mtod(m, u_int16_t *), 2);
1555 m_adj(m, 2);
1556
1557 /* Make room for L2TP header */
5a975a3d 1558 M_PREPEND(m, 12, MB_DONTWAIT);
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1559 if (m == NULL) {
1560 priv->stats.memoryFailures++;
1561 return (ENOBUFS);
1562 }
1563 }
1564
1565 /* Fill in L2TP header */
1566 mtod(m, u_int16_t *)[0] = htons(L2TP_CTRL_HDR);
1567 mtod(m, u_int16_t *)[1] = htons(m->m_pkthdr.len);
1568 mtod(m, u_int16_t *)[2] = priv->conf.peer_id;
1569 mtod(m, u_int16_t *)[3] = session_id;
1570 mtod(m, u_int16_t *)[4] = htons(ns);
1571 mtod(m, u_int16_t *)[5] = htons(seq->nr);
1572
1573 /* Update sequence number info and stats */
1574 priv->stats.xmitPackets++;
1575 priv->stats.xmitOctets += m->m_pkthdr.len;
1576
1577 /* Send packet */
1578 NG_SEND_DATA_ONLY(error, priv->lower, m);
1579 return (error);
1580}
1581
1582#ifdef INVARIANTS
1583/*
1584 * Sanity check sequence number state.
1585 */
1586static void
1587ng_l2tp_seq_check(struct l2tp_seq *seq)
1588{
1589 int self_unack, peer_unack;
1590 int i;
1591
1592#define CHECK(p) KASSERT((p), ("%s: not: %s", __func__, #p))
1593
1594 mtx_lock(&seq->mtx);
1595
1596 self_unack = L2TP_SEQ_DIFF(seq->nr, seq->xack);
1597 peer_unack = L2TP_SEQ_DIFF(seq->ns, seq->rack);
1598 CHECK(seq->wmax <= L2TP_MAX_XWIN);
1599 CHECK(seq->cwnd >= 1);
1600 CHECK(seq->cwnd <= seq->wmax);
1601 CHECK(seq->ssth >= 1);
1602 CHECK(seq->ssth <= seq->wmax);
1603 if (seq->cwnd < seq->ssth)
1604 CHECK(seq->acks == 0);
1605 else
1606 CHECK(seq->acks <= seq->cwnd);
1607 CHECK(self_unack >= 0);
1608 CHECK(peer_unack >= 0);
1609 CHECK(peer_unack <= seq->wmax);
1610 CHECK((self_unack == 0) ^ callout_active(&seq->xack_timer));
1611 CHECK((peer_unack == 0) ^ callout_active(&seq->rack_timer));
1612 for (i = 0; i < peer_unack; i++)
1613 CHECK(seq->xwin[i] != NULL);
1614 for ( ; i < seq->cwnd; i++) /* verify peer's recv window full */
1615 CHECK(seq->xwin[i] == NULL);
1616
1617 mtx_unlock(&seq->mtx);
1618
1619#undef CHECK
1620}
1621#endif /* INVARIANTS */