ng_l2tp.c revision 176962
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: head/sys/netgraph/ng_l2tp.c 176962 2008-03-08 23:55:29Z mav $ 40 */ 41 42/* 43 * L2TP netgraph node type. 44 * 45 * This node type implements the lower layer of the 46 * L2TP protocol as specified in RFC 2661. 47 */ 48 49#include <sys/param.h> 50#include <sys/systm.h> 51#include <sys/kernel.h> 52#include <sys/time.h> 53#include <sys/conf.h> 54#include <sys/mbuf.h> 55#include <sys/malloc.h> 56#include <sys/errno.h> 57#include <sys/libkern.h> 58 59#include <netgraph/ng_message.h> 60#include <netgraph/netgraph.h> 61#include <netgraph/ng_parse.h> 62#include <netgraph/ng_l2tp.h> 63 64#ifdef NG_SEPARATE_MALLOC 65MALLOC_DEFINE(M_NETGRAPH_L2TP, "netgraph_l2tp", "netgraph l2tp node"); 66#else 67#define M_NETGRAPH_L2TP M_NETGRAPH 68#endif 69 70/* L2TP header format (first 2 bytes only) */ 71#define L2TP_HDR_CTRL 0x8000 /* control packet */ 72#define L2TP_HDR_LEN 0x4000 /* has length field */ 73#define L2TP_HDR_SEQ 0x0800 /* has ns, nr fields */ 74#define L2TP_HDR_OFF 0x0200 /* has offset field */ 75#define L2TP_HDR_PRIO 0x0100 /* give priority */ 76#define L2TP_HDR_VERS_MASK 0x000f /* version field mask */ 77#define L2TP_HDR_VERSION 0x0002 /* version field */ 78 79/* Bits that must be zero or one in first two bytes of header */ 80#define L2TP_CTRL_0BITS 0x030d /* ctrl: must be 0 */ 81#define L2TP_CTRL_1BITS 0xc802 /* ctrl: must be 1 */ 82#define L2TP_DATA_0BITS 0x800d /* data: must be 0 */ 83#define L2TP_DATA_1BITS 0x0002 /* data: must be 1 */ 84 85/* Standard xmit ctrl and data header bits */ 86#define L2TP_CTRL_HDR (L2TP_HDR_CTRL | L2TP_HDR_LEN \ 87 | L2TP_HDR_SEQ | L2TP_HDR_VERSION) 88#define L2TP_DATA_HDR (L2TP_HDR_VERSION) /* optional: len, seq */ 89 90/* Some hard coded values */ 91#define L2TP_MAX_XWIN 128 /* my max xmit window */ 92#define L2TP_MAX_REXMIT 5 /* default max rexmit */ 93#define L2TP_MAX_REXMIT_TO 30 /* default rexmit to */ 94#define L2TP_DELAYED_ACK ((hz + 19) / 20) /* delayed ack: 50 ms */ 95 96/* Default data sequence number configuration for new sessions */ 97#define L2TP_CONTROL_DSEQ 1 /* we are the lns */ 98#define L2TP_ENABLE_DSEQ 1 /* enable data seq # */ 99 100/* Compare sequence numbers using circular math */ 101#define L2TP_SEQ_DIFF(x, y) ((int)((int16_t)(x) - (int16_t)(y))) 102 103/* 104 * Sequence number state 105 * 106 * Invariants: 107 * - If cwnd < ssth, we're doing slow start, otherwise congestion avoidance 108 * - The number of unacknowledged xmit packets is (ns - rack) <= seq->wmax 109 * - The first (ns - rack) mbuf's in xwin[] array are copies of these 110 * unacknowledged packets; the remainder of xwin[] consists first of 111 * zero or more further untransmitted packets in the transmit queue 112 * - We try to keep the peer's receive window as full as possible. 113 * Therefore, (i < cwnd && xwin[i] != NULL) implies (ns - rack) > i. 114 * - rack_timer is running iff (ns - rack) > 0 (unack'd xmit'd pkts) 115 * - If xack != nr, there are unacknowledged recv packet(s) (delayed ack) 116 * - xack_timer is running iff xack != nr (unack'd rec'd pkts) 117 */ 118struct l2tp_seq { 119 u_int16_t ns; /* next xmit seq we send */ 120 u_int16_t nr; /* next recv seq we expect */ 121 u_int16_t inproc; /* packet is in processing */ 122 u_int16_t rack; /* last 'nr' we rec'd */ 123 u_int16_t xack; /* last 'nr' we sent */ 124 u_int16_t wmax; /* peer's max recv window */ 125 u_int16_t cwnd; /* current congestion window */ 126 u_int16_t ssth; /* slow start threshold */ 127 u_int16_t acks; /* # consecutive acks rec'd */ 128 u_int16_t rexmits; /* # retransmits sent */ 129 struct callout rack_timer; /* retransmit timer */ 130 struct callout xack_timer; /* delayed ack timer */ 131 struct mbuf *xwin[L2TP_MAX_XWIN]; /* transmit window */ 132 struct mtx mtx; /* seq mutex */ 133}; 134 135/* Node private data */ 136struct ng_l2tp_private { 137 node_p node; /* back pointer to node */ 138 hook_p ctrl; /* hook to upper layers */ 139 hook_p lower; /* hook to lower layers */ 140 struct ng_l2tp_config conf; /* node configuration */ 141 struct ng_l2tp_stats stats; /* node statistics */ 142 struct l2tp_seq seq; /* ctrl sequence number state */ 143 ng_ID_t ftarget; /* failure message target */ 144}; 145typedef struct ng_l2tp_private *priv_p; 146 147/* Hook private data (data session hooks only) */ 148struct ng_l2tp_hook_private { 149 struct ng_l2tp_sess_config conf; /* hook/session config */ 150 struct ng_l2tp_session_stats stats; /* per sessions statistics */ 151 u_int16_t ns; /* data ns sequence number */ 152 u_int16_t nr; /* data nr sequence number */ 153}; 154typedef struct ng_l2tp_hook_private *hookpriv_p; 155 156/* Netgraph node methods */ 157static ng_constructor_t ng_l2tp_constructor; 158static ng_rcvmsg_t ng_l2tp_rcvmsg; 159static ng_shutdown_t ng_l2tp_shutdown; 160static ng_newhook_t ng_l2tp_newhook; 161static ng_rcvdata_t ng_l2tp_rcvdata; 162static ng_rcvdata_t ng_l2tp_rcvdata_lower; 163static ng_rcvdata_t ng_l2tp_rcvdata_ctrl; 164static ng_disconnect_t ng_l2tp_disconnect; 165 166/* Internal functions */ 167static int ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns); 168 169static void ng_l2tp_seq_init(priv_p priv); 170static int ng_l2tp_seq_set(priv_p priv, 171 const struct ng_l2tp_seq_config *conf); 172static int ng_l2tp_seq_adjust(priv_p priv, 173 const struct ng_l2tp_config *conf); 174static void ng_l2tp_seq_reset(priv_p priv); 175static void ng_l2tp_seq_failure(priv_p priv); 176static void ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr); 177static void ng_l2tp_seq_xack_timeout(node_p node, hook_p hook, 178 void *arg1, int arg2); 179static void ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, 180 void *arg1, int arg2); 181 182static ng_fn_eachhook ng_l2tp_find_session; 183static ng_fn_eachhook ng_l2tp_reset_session; 184 185#ifdef INVARIANTS 186static void ng_l2tp_seq_check(struct l2tp_seq *seq); 187#endif 188 189/* Parse type for struct ng_l2tp_seq_config. */ 190static const struct ng_parse_struct_field 191 ng_l2tp_seq_config_fields[] = NG_L2TP_SEQ_CONFIG_TYPE_INFO; 192static const struct ng_parse_type ng_l2tp_seq_config_type = { 193 &ng_parse_struct_type, 194 &ng_l2tp_seq_config_fields 195}; 196 197/* Parse type for struct ng_l2tp_config */ 198static const struct ng_parse_struct_field 199 ng_l2tp_config_type_fields[] = NG_L2TP_CONFIG_TYPE_INFO; 200static const struct ng_parse_type ng_l2tp_config_type = { 201 &ng_parse_struct_type, 202 &ng_l2tp_config_type_fields, 203}; 204 205/* Parse type for struct ng_l2tp_sess_config */ 206static const struct ng_parse_struct_field 207 ng_l2tp_sess_config_type_fields[] = NG_L2TP_SESS_CONFIG_TYPE_INFO; 208static const struct ng_parse_type ng_l2tp_sess_config_type = { 209 &ng_parse_struct_type, 210 &ng_l2tp_sess_config_type_fields, 211}; 212 213/* Parse type for struct ng_l2tp_stats */ 214static const struct ng_parse_struct_field 215 ng_l2tp_stats_type_fields[] = NG_L2TP_STATS_TYPE_INFO; 216static const struct ng_parse_type ng_l2tp_stats_type = { 217 &ng_parse_struct_type, 218 &ng_l2tp_stats_type_fields 219}; 220 221/* Parse type for struct ng_l2tp_session_stats. */ 222static const struct ng_parse_struct_field 223 ng_l2tp_session_stats_type_fields[] = NG_L2TP_SESSION_STATS_TYPE_INFO; 224static const struct ng_parse_type ng_l2tp_session_stats_type = { 225 &ng_parse_struct_type, 226 &ng_l2tp_session_stats_type_fields 227}; 228 229/* List of commands and how to convert arguments to/from ASCII */ 230static const struct ng_cmdlist ng_l2tp_cmdlist[] = { 231 { 232 NGM_L2TP_COOKIE, 233 NGM_L2TP_SET_CONFIG, 234 "setconfig", 235 &ng_l2tp_config_type, 236 NULL 237 }, 238 { 239 NGM_L2TP_COOKIE, 240 NGM_L2TP_GET_CONFIG, 241 "getconfig", 242 NULL, 243 &ng_l2tp_config_type 244 }, 245 { 246 NGM_L2TP_COOKIE, 247 NGM_L2TP_SET_SESS_CONFIG, 248 "setsessconfig", 249 &ng_l2tp_sess_config_type, 250 NULL 251 }, 252 { 253 NGM_L2TP_COOKIE, 254 NGM_L2TP_GET_SESS_CONFIG, 255 "getsessconfig", 256 &ng_parse_hint16_type, 257 &ng_l2tp_sess_config_type 258 }, 259 { 260 NGM_L2TP_COOKIE, 261 NGM_L2TP_GET_STATS, 262 "getstats", 263 NULL, 264 &ng_l2tp_stats_type 265 }, 266 { 267 NGM_L2TP_COOKIE, 268 NGM_L2TP_CLR_STATS, 269 "clrstats", 270 NULL, 271 NULL 272 }, 273 { 274 NGM_L2TP_COOKIE, 275 NGM_L2TP_GETCLR_STATS, 276 "getclrstats", 277 NULL, 278 &ng_l2tp_stats_type 279 }, 280 { 281 NGM_L2TP_COOKIE, 282 NGM_L2TP_GET_SESSION_STATS, 283 "getsessstats", 284 &ng_parse_int16_type, 285 &ng_l2tp_session_stats_type 286 }, 287 { 288 NGM_L2TP_COOKIE, 289 NGM_L2TP_CLR_SESSION_STATS, 290 "clrsessstats", 291 &ng_parse_int16_type, 292 NULL 293 }, 294 { 295 NGM_L2TP_COOKIE, 296 NGM_L2TP_GETCLR_SESSION_STATS, 297 "getclrsessstats", 298 &ng_parse_int16_type, 299 &ng_l2tp_session_stats_type 300 }, 301 { 302 NGM_L2TP_COOKIE, 303 NGM_L2TP_ACK_FAILURE, 304 "ackfailure", 305 NULL, 306 NULL 307 }, 308 { 309 NGM_L2TP_COOKIE, 310 NGM_L2TP_SET_SEQ, 311 "setsequence", 312 &ng_l2tp_seq_config_type, 313 NULL 314 }, 315 { 0 } 316}; 317 318/* Node type descriptor */ 319static struct ng_type ng_l2tp_typestruct = { 320 .version = NG_ABI_VERSION, 321 .name = NG_L2TP_NODE_TYPE, 322 .constructor = ng_l2tp_constructor, 323 .rcvmsg = ng_l2tp_rcvmsg, 324 .shutdown = ng_l2tp_shutdown, 325 .newhook = ng_l2tp_newhook, 326 .rcvdata = ng_l2tp_rcvdata, 327 .disconnect = ng_l2tp_disconnect, 328 .cmdlist = ng_l2tp_cmdlist, 329}; 330NETGRAPH_INIT(l2tp, &ng_l2tp_typestruct); 331 332/* Sequence number state sanity checking */ 333#ifdef INVARIANTS 334#define L2TP_SEQ_CHECK(seq) ng_l2tp_seq_check(seq) 335#else 336#define L2TP_SEQ_CHECK(x) do { } while (0) 337#endif 338 339/* memmove macro */ 340#define memmove(d, s, l) bcopy(s, d, l) 341 342/* Whether to use m_copypacket() or m_dup() */ 343#define L2TP_COPY_MBUF m_copypacket 344 345#define ERROUT(x) do { error = (x); goto done; } while (0) 346 347/************************************************************************ 348 NETGRAPH NODE STUFF 349************************************************************************/ 350 351/* 352 * Node type constructor 353 */ 354static int 355ng_l2tp_constructor(node_p node) 356{ 357 priv_p priv; 358 359 /* Allocate private structure */ 360 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_L2TP, M_NOWAIT | M_ZERO); 361 if (priv == NULL) 362 return (ENOMEM); 363 NG_NODE_SET_PRIVATE(node, priv); 364 priv->node = node; 365 366 /* Apply a semi-reasonable default configuration */ 367 priv->conf.peer_win = 1; 368 priv->conf.rexmit_max = L2TP_MAX_REXMIT; 369 priv->conf.rexmit_max_to = L2TP_MAX_REXMIT_TO; 370 371 /* Initialize sequence number state */ 372 ng_l2tp_seq_init(priv); 373 374 /* Done */ 375 return (0); 376} 377 378/* 379 * Give our OK for a hook to be added. 380 */ 381static int 382ng_l2tp_newhook(node_p node, hook_p hook, const char *name) 383{ 384 const priv_p priv = NG_NODE_PRIVATE(node); 385 386 /* Check hook name */ 387 if (strcmp(name, NG_L2TP_HOOK_CTRL) == 0) { 388 if (priv->ctrl != NULL) 389 return (EISCONN); 390 priv->ctrl = hook; 391 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_ctrl); 392 } else if (strcmp(name, NG_L2TP_HOOK_LOWER) == 0) { 393 if (priv->lower != NULL) 394 return (EISCONN); 395 priv->lower = hook; 396 NG_HOOK_SET_RCVDATA(hook, ng_l2tp_rcvdata_lower); 397 } else { 398 static const char hexdig[16] = "0123456789abcdef"; 399 u_int16_t session_id; 400 hookpriv_p hpriv; 401 const char *hex; 402 int i; 403 int j; 404 405 /* Parse hook name to get session ID */ 406 if (strncmp(name, NG_L2TP_HOOK_SESSION_P, 407 sizeof(NG_L2TP_HOOK_SESSION_P) - 1) != 0) 408 return (EINVAL); 409 hex = name + sizeof(NG_L2TP_HOOK_SESSION_P) - 1; 410 for (session_id = i = 0; i < 4; i++) { 411 for (j = 0; j < 16 && hex[i] != hexdig[j]; j++); 412 if (j == 16) 413 return (EINVAL); 414 session_id = (session_id << 4) | j; 415 } 416 if (hex[i] != '\0') 417 return (EINVAL); 418 419 /* Create hook private structure */ 420 MALLOC(hpriv, hookpriv_p, 421 sizeof(*hpriv), M_NETGRAPH_L2TP, M_NOWAIT | M_ZERO); 422 if (hpriv == NULL) 423 return (ENOMEM); 424 hpriv->conf.session_id = htons(session_id); 425 hpriv->conf.control_dseq = L2TP_CONTROL_DSEQ; 426 hpriv->conf.enable_dseq = L2TP_ENABLE_DSEQ; 427 NG_HOOK_SET_PRIVATE(hook, hpriv); 428 } 429 430 /* Done */ 431 return (0); 432} 433 434/* 435 * Receive a control message. 436 */ 437static int 438ng_l2tp_rcvmsg(node_p node, item_p item, hook_p lasthook) 439{ 440 const priv_p priv = NG_NODE_PRIVATE(node); 441 struct ng_mesg *resp = NULL; 442 struct ng_mesg *msg; 443 int error = 0; 444 445 NGI_GET_MSG(item, msg); 446 switch (msg->header.typecookie) { 447 case NGM_L2TP_COOKIE: 448 switch (msg->header.cmd) { 449 case NGM_L2TP_SET_CONFIG: 450 { 451 struct ng_l2tp_config *const conf = 452 (struct ng_l2tp_config *)msg->data; 453 454 /* Check for invalid or illegal config */ 455 if (msg->header.arglen != sizeof(*conf)) { 456 error = EINVAL; 457 break; 458 } 459 conf->enabled = !!conf->enabled; 460 conf->match_id = !!conf->match_id; 461 conf->tunnel_id = htons(conf->tunnel_id); 462 conf->peer_id = htons(conf->peer_id); 463 if (priv->conf.enabled 464 && ((priv->conf.tunnel_id != 0 465 && conf->tunnel_id != priv->conf.tunnel_id) 466 || ((priv->conf.peer_id != 0 467 && conf->peer_id != priv->conf.peer_id)))) { 468 error = EBUSY; 469 break; 470 } 471 472 /* Save calling node as failure target */ 473 priv->ftarget = NGI_RETADDR(item); 474 475 /* Adjust sequence number state */ 476 if ((error = ng_l2tp_seq_adjust(priv, conf)) != 0) 477 break; 478 479 /* Update node's config */ 480 priv->conf = *conf; 481 break; 482 } 483 case NGM_L2TP_GET_CONFIG: 484 { 485 struct ng_l2tp_config *conf; 486 487 NG_MKRESPONSE(resp, msg, sizeof(*conf), M_NOWAIT); 488 if (resp == NULL) { 489 error = ENOMEM; 490 break; 491 } 492 conf = (struct ng_l2tp_config *)resp->data; 493 *conf = priv->conf; 494 495 /* Put ID's in host order */ 496 conf->tunnel_id = ntohs(conf->tunnel_id); 497 conf->peer_id = ntohs(conf->peer_id); 498 break; 499 } 500 case NGM_L2TP_SET_SESS_CONFIG: 501 { 502 struct ng_l2tp_sess_config *const conf = 503 (struct ng_l2tp_sess_config *)msg->data; 504 hookpriv_p hpriv; 505 hook_p hook; 506 507 /* Check for invalid or illegal config. */ 508 if (msg->header.arglen != sizeof(*conf)) { 509 error = EINVAL; 510 break; 511 } 512 513 /* Put ID's in network order */ 514 conf->session_id = htons(conf->session_id); 515 conf->peer_id = htons(conf->peer_id); 516 517 /* Find matching hook */ 518 NG_NODE_FOREACH_HOOK(node, ng_l2tp_find_session, 519 (void *)(uintptr_t)conf->session_id, hook); 520 if (hook == NULL) { 521 error = ENOENT; 522 break; 523 } 524 hpriv = NG_HOOK_PRIVATE(hook); 525 526 /* Update hook's config */ 527 hpriv->conf = *conf; 528 break; 529 } 530 case NGM_L2TP_GET_SESS_CONFIG: 531 { 532 struct ng_l2tp_sess_config *conf; 533 u_int16_t session_id; 534 hookpriv_p hpriv; 535 hook_p hook; 536 537 /* Get session ID */ 538 if (msg->header.arglen != sizeof(session_id)) { 539 error = EINVAL; 540 break; 541 } 542 memcpy(&session_id, msg->data, 2); 543 session_id = htons(session_id); 544 545 /* Find matching hook */ 546 NG_NODE_FOREACH_HOOK(node, ng_l2tp_find_session, 547 (void *)(uintptr_t)session_id, hook); 548 if (hook == NULL) { 549 error = ENOENT; 550 break; 551 } 552 hpriv = NG_HOOK_PRIVATE(hook); 553 554 /* Send response */ 555 NG_MKRESPONSE(resp, msg, sizeof(hpriv->conf), M_NOWAIT); 556 if (resp == NULL) { 557 error = ENOMEM; 558 break; 559 } 560 conf = (struct ng_l2tp_sess_config *)resp->data; 561 *conf = hpriv->conf; 562 563 /* Put ID's in host order */ 564 conf->session_id = ntohs(conf->session_id); 565 conf->peer_id = ntohs(conf->peer_id); 566 break; 567 } 568 case NGM_L2TP_GET_STATS: 569 case NGM_L2TP_CLR_STATS: 570 case NGM_L2TP_GETCLR_STATS: 571 { 572 if (msg->header.cmd != NGM_L2TP_CLR_STATS) { 573 NG_MKRESPONSE(resp, msg, 574 sizeof(priv->stats), M_NOWAIT); 575 if (resp == NULL) { 576 error = ENOMEM; 577 break; 578 } 579 memcpy(resp->data, 580 &priv->stats, sizeof(priv->stats)); 581 } 582 if (msg->header.cmd != NGM_L2TP_GET_STATS) 583 memset(&priv->stats, 0, sizeof(priv->stats)); 584 break; 585 } 586 case NGM_L2TP_GET_SESSION_STATS: 587 case NGM_L2TP_CLR_SESSION_STATS: 588 case NGM_L2TP_GETCLR_SESSION_STATS: 589 { 590 uint16_t session_id; 591 hookpriv_p hpriv; 592 hook_p hook; 593 594 /* Get session ID. */ 595 if (msg->header.arglen != sizeof(session_id)) { 596 error = EINVAL; 597 break; 598 } 599 bcopy(msg->data, &session_id, sizeof(uint16_t)); 600 session_id = htons(session_id); 601 602 /* Find matching hook. */ 603 NG_NODE_FOREACH_HOOK(node, ng_l2tp_find_session, 604 (void *)(uintptr_t)session_id, hook); 605 if (hook == NULL) { 606 error = ENOENT; 607 break; 608 } 609 hpriv = NG_HOOK_PRIVATE(hook); 610 611 if (msg->header.cmd != NGM_L2TP_CLR_SESSION_STATS) { 612 NG_MKRESPONSE(resp, msg, 613 sizeof(hpriv->stats), M_NOWAIT); 614 if (resp == NULL) { 615 error = ENOMEM; 616 break; 617 } 618 bcopy(&hpriv->stats, resp->data, 619 sizeof(hpriv->stats)); 620 } 621 if (msg->header.cmd != NGM_L2TP_GET_SESSION_STATS) 622 bzero(&hpriv->stats, sizeof(hpriv->stats)); 623 break; 624 } 625 case NGM_L2TP_SET_SEQ: 626 { 627 struct ng_l2tp_seq_config *const conf = 628 (struct ng_l2tp_seq_config *)msg->data; 629 630 /* Check for invalid or illegal seq config. */ 631 if (msg->header.arglen != sizeof(*conf)) { 632 error = EINVAL; 633 break; 634 } 635 conf->ns = htons(conf->ns); 636 conf->nr = htons(conf->nr); 637 conf->rack = htons(conf->rack); 638 conf->xack = htons(conf->xack); 639 640 /* Set sequence numbers. */ 641 error = ng_l2tp_seq_set(priv, conf); 642 break; 643 } 644 default: 645 error = EINVAL; 646 break; 647 } 648 break; 649 default: 650 error = EINVAL; 651 break; 652 } 653 654 /* Done */ 655 NG_RESPOND_MSG(error, node, item, resp); 656 NG_FREE_MSG(msg); 657 return (error); 658} 659 660/* 661 * Destroy node 662 */ 663static int 664ng_l2tp_shutdown(node_p node) 665{ 666 const priv_p priv = NG_NODE_PRIVATE(node); 667 struct l2tp_seq *const seq = &priv->seq; 668 669 /* Sanity check */ 670 L2TP_SEQ_CHECK(seq); 671 672 /* Reset sequence number state */ 673 ng_l2tp_seq_reset(priv); 674 675 /* Free private data if neither timer is running */ 676 ng_uncallout(&seq->rack_timer, node); 677 ng_uncallout(&seq->xack_timer, node); 678 679 mtx_destroy(&seq->mtx); 680 681 FREE(priv, M_NETGRAPH_L2TP); 682 683 /* Unref node */ 684 NG_NODE_UNREF(node); 685 return (0); 686} 687 688/* 689 * Hook disconnection 690 */ 691static int 692ng_l2tp_disconnect(hook_p hook) 693{ 694 const node_p node = NG_HOOK_NODE(hook); 695 const priv_p priv = NG_NODE_PRIVATE(node); 696 697 /* Zero out hook pointer */ 698 if (hook == priv->ctrl) 699 priv->ctrl = NULL; 700 else if (hook == priv->lower) 701 priv->lower = NULL; 702 else { 703 FREE(NG_HOOK_PRIVATE(hook), M_NETGRAPH_L2TP); 704 NG_HOOK_SET_PRIVATE(hook, NULL); 705 } 706 707 /* Go away if no longer connected to anything */ 708 if (NG_NODE_NUMHOOKS(node) == 0 && NG_NODE_IS_VALID(node)) 709 ng_rmnode_self(node); 710 return (0); 711} 712 713/************************************************************************* 714 INTERNAL FUNCTIONS 715*************************************************************************/ 716 717/* 718 * Find the hook with a given session ID. 719 */ 720static int 721ng_l2tp_find_session(hook_p hook, void *arg) 722{ 723 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook); 724 const u_int16_t sid = (u_int16_t)(uintptr_t)arg; 725 726 if (hpriv == NULL || hpriv->conf.session_id != sid) 727 return (-1); 728 return (0); 729} 730 731/* 732 * Reset a hook's session state. 733 */ 734static int 735ng_l2tp_reset_session(hook_p hook, void *arg) 736{ 737 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook); 738 739 if (hpriv != NULL) { 740 hpriv->conf.control_dseq = 0; 741 hpriv->conf.enable_dseq = 0; 742 bzero(&hpriv->conf, sizeof(struct ng_l2tp_session_stats)); 743 hpriv->nr = 0; 744 hpriv->ns = 0; 745 } 746 return (-1); 747} 748 749/* 750 * Handle an incoming frame from below. 751 */ 752static int 753ng_l2tp_rcvdata_lower(hook_p h, item_p item) 754{ 755 static const u_int16_t req_bits[2][2] = { 756 { L2TP_DATA_0BITS, L2TP_DATA_1BITS }, 757 { L2TP_CTRL_0BITS, L2TP_CTRL_1BITS }, 758 }; 759 const node_p node = NG_HOOK_NODE(h); 760 const priv_p priv = NG_NODE_PRIVATE(node); 761 hookpriv_p hpriv = NULL; 762 hook_p hook = NULL; 763 u_int16_t ids[2]; 764 struct mbuf *m; 765 u_int16_t hdr; 766 u_int16_t ns; 767 u_int16_t nr; 768 int is_ctrl; 769 int error; 770 int len, plen; 771 772 /* Sanity check */ 773 L2TP_SEQ_CHECK(&priv->seq); 774 775 /* If not configured, reject */ 776 if (!priv->conf.enabled) { 777 NG_FREE_ITEM(item); 778 ERROUT(ENXIO); 779 } 780 781 /* Grab mbuf */ 782 NGI_GET_M(item, m); 783 784 /* Remember full packet length; needed for per session accounting. */ 785 plen = m->m_pkthdr.len; 786 787 /* Update stats */ 788 priv->stats.recvPackets++; 789 priv->stats.recvOctets += plen; 790 791 /* Get initial header */ 792 if (m->m_pkthdr.len < 6) { 793 priv->stats.recvRunts++; 794 NG_FREE_ITEM(item); 795 NG_FREE_M(m); 796 ERROUT(EINVAL); 797 } 798 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) { 799 priv->stats.memoryFailures++; 800 NG_FREE_ITEM(item); 801 ERROUT(EINVAL); 802 } 803 hdr = ntohs(*mtod(m, u_int16_t *)); 804 m_adj(m, 2); 805 806 /* Check required header bits and minimum length */ 807 is_ctrl = (hdr & L2TP_HDR_CTRL) != 0; 808 if ((hdr & req_bits[is_ctrl][0]) != 0 809 || (~hdr & req_bits[is_ctrl][1]) != 0) { 810 priv->stats.recvInvalid++; 811 NG_FREE_ITEM(item); 812 NG_FREE_M(m); 813 ERROUT(EINVAL); 814 } 815 if (m->m_pkthdr.len < 4 /* tunnel, session id */ 816 + (2 * ((hdr & L2TP_HDR_LEN) != 0)) /* length field */ 817 + (4 * ((hdr & L2TP_HDR_SEQ) != 0)) /* seq # fields */ 818 + (2 * ((hdr & L2TP_HDR_OFF) != 0))) { /* offset field */ 819 priv->stats.recvRunts++; 820 NG_FREE_ITEM(item); 821 NG_FREE_M(m); 822 ERROUT(EINVAL); 823 } 824 825 /* Get and validate length field if present */ 826 if ((hdr & L2TP_HDR_LEN) != 0) { 827 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) { 828 priv->stats.memoryFailures++; 829 NG_FREE_ITEM(item); 830 ERROUT(EINVAL); 831 } 832 len = (u_int16_t)ntohs(*mtod(m, u_int16_t *)) - 4; 833 m_adj(m, 2); 834 if (len < 0 || len > m->m_pkthdr.len) { 835 priv->stats.recvInvalid++; 836 NG_FREE_ITEM(item); 837 NG_FREE_M(m); 838 ERROUT(EINVAL); 839 } 840 if (len < m->m_pkthdr.len) /* trim extra bytes */ 841 m_adj(m, -(m->m_pkthdr.len - len)); 842 } 843 844 /* Get tunnel ID and session ID */ 845 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 846 priv->stats.memoryFailures++; 847 NG_FREE_ITEM(item); 848 ERROUT(EINVAL); 849 } 850 memcpy(ids, mtod(m, u_int16_t *), 4); 851 m_adj(m, 4); 852 853 /* Check tunnel ID */ 854 if (ids[0] != priv->conf.tunnel_id 855 && (priv->conf.match_id || ids[0] != 0)) { 856 priv->stats.recvWrongTunnel++; 857 NG_FREE_ITEM(item); 858 NG_FREE_M(m); 859 ERROUT(EADDRNOTAVAIL); 860 } 861 862 /* Check session ID (for data packets only) */ 863 if ((hdr & L2TP_HDR_CTRL) == 0) { 864 NG_NODE_FOREACH_HOOK(node, ng_l2tp_find_session, 865 (void *)(uintptr_t)ids[1], hook); 866 if (hook == NULL) { 867 priv->stats.recvUnknownSID++; 868 NG_FREE_ITEM(item); 869 NG_FREE_M(m); 870 ERROUT(ENOTCONN); 871 } 872 hpriv = NG_HOOK_PRIVATE(hook); 873 } 874 875 /* Get Ns, Nr fields if present */ 876 if ((hdr & L2TP_HDR_SEQ) != 0) { 877 if (m->m_len < 4 && (m = m_pullup(m, 4)) == NULL) { 878 priv->stats.memoryFailures++; 879 NG_FREE_ITEM(item); 880 ERROUT(EINVAL); 881 } 882 memcpy(&ns, &mtod(m, u_int16_t *)[0], 2); 883 ns = ntohs(ns); 884 memcpy(&nr, &mtod(m, u_int16_t *)[1], 2); 885 nr = ntohs(nr); 886 m_adj(m, 4); 887 } 888 889 /* Strip offset padding if present */ 890 if ((hdr & L2TP_HDR_OFF) != 0) { 891 u_int16_t offset; 892 893 /* Get length of offset padding */ 894 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) { 895 priv->stats.memoryFailures++; 896 NG_FREE_ITEM(item); 897 ERROUT(EINVAL); 898 } 899 memcpy(&offset, mtod(m, u_int16_t *), 2); 900 offset = ntohs(offset); 901 902 /* Trim offset padding */ 903 if ((2+offset) > m->m_pkthdr.len) { 904 priv->stats.recvInvalid++; 905 NG_FREE_ITEM(item); 906 NG_FREE_M(m); 907 ERROUT(EINVAL); 908 } 909 m_adj(m, 2+offset); 910 } 911 912 /* Handle control packets */ 913 if ((hdr & L2TP_HDR_CTRL) != 0) { 914 struct l2tp_seq *const seq = &priv->seq; 915 916 /* Handle receive ack sequence number Nr */ 917 ng_l2tp_seq_recv_nr(priv, nr); 918 919 /* Discard ZLB packets */ 920 if (m->m_pkthdr.len == 0) { 921 priv->stats.recvZLBs++; 922 NG_FREE_ITEM(item); 923 NG_FREE_M(m); 924 ERROUT(0); 925 } 926 927 mtx_lock(&seq->mtx); 928 /* 929 * If not what we expect or we are busy, drop packet and 930 * send an immediate ZLB ack. 931 */ 932 if (ns != seq->nr || seq->inproc) { 933 if (L2TP_SEQ_DIFF(ns, seq->nr) <= 0) 934 priv->stats.recvDuplicates++; 935 else 936 priv->stats.recvOutOfOrder++; 937 mtx_unlock(&seq->mtx); 938 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns); 939 NG_FREE_ITEM(item); 940 NG_FREE_M(m); 941 ERROUT(0); 942 } 943 /* 944 * Until we deliver this packet we can't receive next one as 945 * we have no information for sending ack. 946 */ 947 seq->inproc = 1; 948 mtx_unlock(&seq->mtx); 949 950 /* Prepend session ID to packet. */ 951 M_PREPEND(m, 2, M_DONTWAIT); 952 if (m == NULL) { 953 priv->stats.memoryFailures++; 954 NG_FREE_ITEM(item); 955 ERROUT(ENOBUFS); 956 } 957 memcpy(mtod(m, u_int16_t *), &ids[1], 2); 958 959 /* Deliver packet to upper layers */ 960 NG_FWD_NEW_DATA(error, item, priv->ctrl, m); 961 962 mtx_lock(&seq->mtx); 963 /* Ready to process next packet. */ 964 seq->inproc = 0; 965 966 /* If packet was successfully delivered send ack. */ 967 if (error == 0) { 968 /* Update recv sequence number */ 969 seq->nr++; 970 /* Start receive ack timer, if not already running */ 971 if (!callout_active(&seq->xack_timer)) { 972 ng_callout(&seq->xack_timer, priv->node, NULL, 973 L2TP_DELAYED_ACK, ng_l2tp_seq_xack_timeout, 974 NULL, 0); 975 } 976 } 977 mtx_unlock(&seq->mtx); 978 979 ERROUT(error); 980 } 981 982 /* Per session packet, account it. */ 983 hpriv->stats.recvPackets++; 984 hpriv->stats.recvOctets += plen; 985 986 /* Follow peer's lead in data sequencing, if configured to do so */ 987 if (!hpriv->conf.control_dseq) 988 hpriv->conf.enable_dseq = ((hdr & L2TP_HDR_SEQ) != 0); 989 990 /* Handle data sequence numbers if present and enabled */ 991 if ((hdr & L2TP_HDR_SEQ) != 0) { 992 if (hpriv->conf.enable_dseq 993 && L2TP_SEQ_DIFF(ns, hpriv->nr) < 0) { 994 NG_FREE_ITEM(item); /* duplicate or out of order */ 995 NG_FREE_M(m); 996 priv->stats.recvDataDrops++; 997 ERROUT(0); 998 } 999 hpriv->nr = ns + 1; 1000 } 1001 1002 /* Drop empty data packets */ 1003 if (m->m_pkthdr.len == 0) { 1004 NG_FREE_ITEM(item); 1005 NG_FREE_M(m); 1006 ERROUT(0); 1007 } 1008 1009 /* Deliver data */ 1010 NG_FWD_NEW_DATA(error, item, hook, m); 1011done: 1012 /* Done */ 1013 L2TP_SEQ_CHECK(&priv->seq); 1014 return (error); 1015} 1016 1017/* 1018 * Handle an outgoing control frame. 1019 */ 1020static int 1021ng_l2tp_rcvdata_ctrl(hook_p hook, item_p item) 1022{ 1023 const node_p node = NG_HOOK_NODE(hook); 1024 const priv_p priv = NG_NODE_PRIVATE(node); 1025 struct l2tp_seq *const seq = &priv->seq; 1026 struct mbuf *m; 1027 int error; 1028 int i; 1029 u_int16_t ns; 1030 1031 /* Sanity check */ 1032 L2TP_SEQ_CHECK(&priv->seq); 1033 1034 /* If not configured, reject */ 1035 if (!priv->conf.enabled) { 1036 NG_FREE_ITEM(item); 1037 ERROUT(ENXIO); 1038 } 1039 1040 /* Grab mbuf and discard other stuff XXX */ 1041 NGI_GET_M(item, m); 1042 NG_FREE_ITEM(item); 1043 1044 /* Packet should have session ID prepended */ 1045 if (m->m_pkthdr.len < 2) { 1046 priv->stats.xmitInvalid++; 1047 m_freem(m); 1048 ERROUT(EINVAL); 1049 } 1050 1051 /* Check max length */ 1052 if (m->m_pkthdr.len >= 0x10000 - 14) { 1053 priv->stats.xmitTooBig++; 1054 m_freem(m); 1055 ERROUT(EOVERFLOW); 1056 } 1057 1058 mtx_lock(&seq->mtx); 1059 1060 /* Find next empty slot in transmit queue */ 1061 for (i = 0; i < L2TP_MAX_XWIN && seq->xwin[i] != NULL; i++); 1062 if (i == L2TP_MAX_XWIN) { 1063 mtx_unlock(&seq->mtx); 1064 priv->stats.xmitDrops++; 1065 m_freem(m); 1066 ERROUT(ENOBUFS); 1067 } 1068 seq->xwin[i] = m; 1069 1070 /* If peer's receive window is already full, nothing else to do */ 1071 if (i >= seq->cwnd) { 1072 mtx_unlock(&seq->mtx); 1073 ERROUT(0); 1074 } 1075 1076 /* Start retransmit timer if not already running */ 1077 if (!callout_active(&seq->rack_timer)) 1078 ng_callout(&seq->rack_timer, node, NULL, 1079 hz, ng_l2tp_seq_rack_timeout, NULL, 0); 1080 1081 ns = seq->ns++; 1082 1083 mtx_unlock(&seq->mtx); 1084 1085 /* Copy packet */ 1086 if ((m = L2TP_COPY_MBUF(m, M_DONTWAIT)) == NULL) { 1087 priv->stats.memoryFailures++; 1088 ERROUT(ENOBUFS); 1089 } 1090 1091 /* Send packet and increment xmit sequence number */ 1092 error = ng_l2tp_xmit_ctrl(priv, m, ns); 1093done: 1094 /* Done */ 1095 L2TP_SEQ_CHECK(&priv->seq); 1096 return (error); 1097} 1098 1099/* 1100 * Handle an outgoing data frame. 1101 */ 1102static int 1103ng_l2tp_rcvdata(hook_p hook, item_p item) 1104{ 1105 const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 1106 const hookpriv_p hpriv = NG_HOOK_PRIVATE(hook); 1107 struct mbuf *m; 1108 u_int16_t hdr; 1109 int error; 1110 int i = 1; 1111 1112 /* Sanity check */ 1113 L2TP_SEQ_CHECK(&priv->seq); 1114 1115 /* If not configured, reject */ 1116 if (!priv->conf.enabled) { 1117 NG_FREE_ITEM(item); 1118 ERROUT(ENXIO); 1119 } 1120 1121 /* Get mbuf */ 1122 NGI_GET_M(item, m); 1123 1124 /* Check max length */ 1125 if (m->m_pkthdr.len >= 0x10000 - 12) { 1126 priv->stats.xmitDataTooBig++; 1127 NG_FREE_ITEM(item); 1128 NG_FREE_M(m); 1129 ERROUT(EOVERFLOW); 1130 } 1131 1132 /* Prepend L2TP header */ 1133 M_PREPEND(m, 6 1134 + (2 * (hpriv->conf.include_length != 0)) 1135 + (4 * (hpriv->conf.enable_dseq != 0)), 1136 M_DONTWAIT); 1137 if (m == NULL) { 1138 priv->stats.memoryFailures++; 1139 NG_FREE_ITEM(item); 1140 ERROUT(ENOBUFS); 1141 } 1142 hdr = L2TP_DATA_HDR; 1143 if (hpriv->conf.include_length) { 1144 hdr |= L2TP_HDR_LEN; 1145 mtod(m, u_int16_t *)[i++] = htons(m->m_pkthdr.len); 1146 } 1147 mtod(m, u_int16_t *)[i++] = priv->conf.peer_id; 1148 mtod(m, u_int16_t *)[i++] = hpriv->conf.peer_id; 1149 if (hpriv->conf.enable_dseq) { 1150 hdr |= L2TP_HDR_SEQ; 1151 mtod(m, u_int16_t *)[i++] = htons(hpriv->ns); 1152 mtod(m, u_int16_t *)[i++] = htons(hpriv->nr); 1153 hpriv->ns++; 1154 } 1155 mtod(m, u_int16_t *)[0] = htons(hdr); 1156 1157 /* Update per session stats. */ 1158 hpriv->stats.xmitPackets++; 1159 hpriv->stats.xmitOctets += m->m_pkthdr.len; 1160 1161 /* And the global one. */ 1162 priv->stats.xmitPackets++; 1163 priv->stats.xmitOctets += m->m_pkthdr.len; 1164 1165 /* Send packet */ 1166 NG_FWD_NEW_DATA(error, item, priv->lower, m); 1167done: 1168 /* Done */ 1169 L2TP_SEQ_CHECK(&priv->seq); 1170 return (error); 1171} 1172 1173/* 1174 * Send a message to our controlling node that we've failed. 1175 */ 1176static void 1177ng_l2tp_seq_failure(priv_p priv) 1178{ 1179 struct ng_mesg *msg; 1180 int error; 1181 1182 NG_MKMESSAGE(msg, NGM_L2TP_COOKIE, NGM_L2TP_ACK_FAILURE, 0, M_NOWAIT); 1183 if (msg == NULL) 1184 return; 1185 NG_SEND_MSG_ID(error, priv->node, msg, priv->ftarget, 0); 1186} 1187 1188/************************************************************************ 1189 SEQUENCE NUMBER HANDLING 1190************************************************************************/ 1191 1192/* 1193 * Initialize sequence number state. 1194 */ 1195static void 1196ng_l2tp_seq_init(priv_p priv) 1197{ 1198 struct l2tp_seq *const seq = &priv->seq; 1199 1200 KASSERT(priv->conf.peer_win >= 1, 1201 ("%s: peer_win is zero", __func__)); 1202 memset(seq, 0, sizeof(*seq)); 1203 seq->cwnd = 1; 1204 seq->wmax = priv->conf.peer_win; 1205 if (seq->wmax > L2TP_MAX_XWIN) 1206 seq->wmax = L2TP_MAX_XWIN; 1207 seq->ssth = seq->wmax; 1208 ng_callout_init(&seq->rack_timer); 1209 ng_callout_init(&seq->xack_timer); 1210 mtx_init(&seq->mtx, "ng_l2tp", NULL, MTX_DEF); 1211 L2TP_SEQ_CHECK(seq); 1212} 1213 1214/* 1215 * Set sequence number state as given from user. 1216 */ 1217static int 1218ng_l2tp_seq_set(priv_p priv, const struct ng_l2tp_seq_config *conf) 1219{ 1220 struct l2tp_seq *const seq = &priv->seq; 1221 1222 /* If node is enabled, deny update to sequence numbers. */ 1223 if (priv->conf.enabled) 1224 return (EBUSY); 1225 1226 /* We only can handle the simple cases. */ 1227 if (conf->xack != conf->nr || conf->ns != conf->rack) 1228 return (EINVAL); 1229 1230 /* Set ns,nr,rack,xack parameters. */ 1231 seq->ns = conf->ns; 1232 seq->nr = conf->nr; 1233 seq->rack = conf->rack; 1234 seq->xack = conf->xack; 1235 1236 return (0); 1237} 1238 1239/* 1240 * Adjust sequence number state accordingly after reconfiguration. 1241 */ 1242static int 1243ng_l2tp_seq_adjust(priv_p priv, const struct ng_l2tp_config *conf) 1244{ 1245 struct l2tp_seq *const seq = &priv->seq; 1246 u_int16_t new_wmax; 1247 1248 /* If disabling node, reset state sequence number */ 1249 if (!conf->enabled) { 1250 ng_l2tp_seq_reset(priv); 1251 return (0); 1252 } 1253 1254 /* Adjust peer's max recv window; it can only increase */ 1255 new_wmax = conf->peer_win; 1256 if (new_wmax > L2TP_MAX_XWIN) 1257 new_wmax = L2TP_MAX_XWIN; 1258 if (new_wmax == 0) 1259 return (EINVAL); 1260 if (new_wmax < seq->wmax) 1261 return (EBUSY); 1262 seq->wmax = new_wmax; 1263 1264 /* Done */ 1265 return (0); 1266} 1267 1268/* 1269 * Reset sequence number state. 1270 */ 1271static void 1272ng_l2tp_seq_reset(priv_p priv) 1273{ 1274 struct l2tp_seq *const seq = &priv->seq; 1275 hook_p hook; 1276 int i; 1277 1278 /* Sanity check */ 1279 L2TP_SEQ_CHECK(seq); 1280 1281 /* Stop timers */ 1282 ng_uncallout(&seq->rack_timer, priv->node); 1283 ng_uncallout(&seq->xack_timer, priv->node); 1284 1285 /* Free retransmit queue */ 1286 for (i = 0; i < L2TP_MAX_XWIN; i++) { 1287 if (seq->xwin[i] == NULL) 1288 break; 1289 m_freem(seq->xwin[i]); 1290 } 1291 1292 /* Reset session hooks' sequence number states */ 1293 NG_NODE_FOREACH_HOOK(priv->node, ng_l2tp_reset_session, NULL, hook); 1294 1295 /* Reset node's sequence number state */ 1296 seq->ns = 0; 1297 seq->nr = 0; 1298 seq->rack = 0; 1299 seq->xack = 0; 1300 seq->wmax = L2TP_MAX_XWIN; 1301 seq->cwnd = 1; 1302 seq->ssth = seq->wmax; 1303 seq->acks = 0; 1304 seq->rexmits = 0; 1305 bzero(seq->xwin, sizeof(seq->xwin)); 1306 1307 /* Done */ 1308 L2TP_SEQ_CHECK(seq); 1309} 1310 1311/* 1312 * Handle receipt of an acknowledgement value (Nr) from peer. 1313 */ 1314static void 1315ng_l2tp_seq_recv_nr(priv_p priv, u_int16_t nr) 1316{ 1317 struct l2tp_seq *const seq = &priv->seq; 1318 struct mbuf *xwin[L2TP_MAX_XWIN]; /* partial local copy */ 1319 int nack; 1320 int i, j; 1321 uint16_t ns; 1322 1323 mtx_lock(&seq->mtx); 1324 1325 /* Verify peer's ACK is in range */ 1326 if ((nack = L2TP_SEQ_DIFF(nr, seq->rack)) <= 0) { 1327 mtx_unlock(&seq->mtx); 1328 return; /* duplicate ack */ 1329 } 1330 if (L2TP_SEQ_DIFF(nr, seq->ns) > 0) { 1331 mtx_unlock(&seq->mtx); 1332 priv->stats.recvBadAcks++; /* ack for packet not sent */ 1333 return; 1334 } 1335 KASSERT(nack <= L2TP_MAX_XWIN, 1336 ("%s: nack=%d > %d", __func__, nack, L2TP_MAX_XWIN)); 1337 1338 /* Update receive ack stats */ 1339 seq->rack = nr; 1340 seq->rexmits = 0; 1341 1342 /* Free acknowledged packets and shift up packets in the xmit queue */ 1343 for (i = 0; i < nack; i++) 1344 m_freem(seq->xwin[i]); 1345 memmove(seq->xwin, seq->xwin + nack, 1346 (L2TP_MAX_XWIN - nack) * sizeof(*seq->xwin)); 1347 memset(seq->xwin + (L2TP_MAX_XWIN - nack), 0, 1348 nack * sizeof(*seq->xwin)); 1349 1350 /* 1351 * Do slow-start/congestion avoidance windowing algorithm described 1352 * in RFC 2661, Appendix A. Here we handle a multiple ACK as if each 1353 * ACK had arrived separately. 1354 */ 1355 if (seq->cwnd < seq->wmax) { 1356 1357 /* Handle slow start phase */ 1358 if (seq->cwnd < seq->ssth) { 1359 seq->cwnd += nack; 1360 nack = 0; 1361 if (seq->cwnd > seq->ssth) { /* into cg.av. phase */ 1362 nack = seq->cwnd - seq->ssth; 1363 seq->cwnd = seq->ssth; 1364 } 1365 } 1366 1367 /* Handle congestion avoidance phase */ 1368 if (seq->cwnd >= seq->ssth) { 1369 seq->acks += nack; 1370 while (seq->acks >= seq->cwnd) { 1371 seq->acks -= seq->cwnd; 1372 if (seq->cwnd < seq->wmax) 1373 seq->cwnd++; 1374 } 1375 } 1376 } 1377 1378 /* Stop xmit timer */ 1379 if (callout_active(&seq->rack_timer)) 1380 ng_uncallout(&seq->rack_timer, priv->node); 1381 1382 /* If transmit queue is empty, we're done for now */ 1383 if (seq->xwin[0] == NULL) { 1384 mtx_unlock(&seq->mtx); 1385 return; 1386 } 1387 1388 /* Start restransmit timer again */ 1389 ng_callout(&seq->rack_timer, priv->node, NULL, 1390 hz, ng_l2tp_seq_rack_timeout, NULL, 0); 1391 1392 /* 1393 * Send more packets, trying to keep peer's receive window full. 1394 * Make copy of everything we need before lock release. 1395 */ 1396 ns = seq->ns; 1397 j = 0; 1398 while ((i = L2TP_SEQ_DIFF(seq->ns, seq->rack)) < seq->cwnd 1399 && seq->xwin[i] != NULL) { 1400 xwin[j++] = seq->xwin[i]; 1401 seq->ns++; 1402 } 1403 1404 mtx_unlock(&seq->mtx); 1405 1406 /* 1407 * Send prepared. 1408 * If there is a memory error, pretend packet was sent, as it 1409 * will get retransmitted later anyway. 1410 */ 1411 for (i = 0; i < j; i++) { 1412 struct mbuf *m; 1413 if ((m = L2TP_COPY_MBUF(xwin[i], M_DONTWAIT)) == NULL) 1414 priv->stats.memoryFailures++; 1415 else 1416 ng_l2tp_xmit_ctrl(priv, m, ns); 1417 ns++; 1418 } 1419} 1420 1421/* 1422 * Handle an ack timeout. We have an outstanding ack that we 1423 * were hoping to piggy-back, but haven't, so send a ZLB. 1424 */ 1425static void 1426ng_l2tp_seq_xack_timeout(node_p node, hook_p hook, void *arg1, int arg2) 1427{ 1428 const priv_p priv = NG_NODE_PRIVATE(node); 1429 struct l2tp_seq *const seq = &priv->seq; 1430 1431 /* Make sure callout is still active before doing anything */ 1432 if (callout_pending(&seq->xack_timer) || 1433 (!callout_active(&seq->xack_timer))) 1434 return; 1435 1436 /* Sanity check */ 1437 L2TP_SEQ_CHECK(seq); 1438 1439 /* Send a ZLB */ 1440 ng_l2tp_xmit_ctrl(priv, NULL, seq->ns); 1441 1442 /* callout_deactivate() is not needed here 1443 as ng_uncallout() was called by ng_l2tp_xmit_ctrl() */ 1444 1445 /* Sanity check */ 1446 L2TP_SEQ_CHECK(seq); 1447} 1448 1449/* 1450 * Handle a transmit timeout. The peer has failed to respond 1451 * with an ack for our packet, so retransmit it. 1452 */ 1453static void 1454ng_l2tp_seq_rack_timeout(node_p node, hook_p hook, void *arg1, int arg2) 1455{ 1456 const priv_p priv = NG_NODE_PRIVATE(node); 1457 struct l2tp_seq *const seq = &priv->seq; 1458 struct mbuf *m; 1459 u_int delay; 1460 1461 /* Make sure callout is still active before doing anything */ 1462 if (callout_pending(&seq->rack_timer) || 1463 (!callout_active(&seq->rack_timer))) 1464 return; 1465 1466 /* Sanity check */ 1467 L2TP_SEQ_CHECK(seq); 1468 1469 priv->stats.xmitRetransmits++; 1470 1471 /* Have we reached the retransmit limit? If so, notify owner. */ 1472 if (seq->rexmits++ >= priv->conf.rexmit_max) 1473 ng_l2tp_seq_failure(priv); 1474 1475 /* Restart timer, this time with an increased delay */ 1476 delay = (seq->rexmits > 12) ? (1 << 12) : (1 << seq->rexmits); 1477 if (delay > priv->conf.rexmit_max_to) 1478 delay = priv->conf.rexmit_max_to; 1479 ng_callout(&seq->rack_timer, node, NULL, 1480 hz * delay, ng_l2tp_seq_rack_timeout, NULL, 0); 1481 1482 /* Do slow-start/congestion algorithm windowing algorithm */ 1483 seq->ns = seq->rack; 1484 seq->ssth = (seq->cwnd + 1) / 2; 1485 seq->cwnd = 1; 1486 seq->acks = 0; 1487 1488 /* Retransmit oldest unack'd packet */ 1489 if ((m = L2TP_COPY_MBUF(seq->xwin[0], M_DONTWAIT)) == NULL) 1490 priv->stats.memoryFailures++; 1491 else 1492 ng_l2tp_xmit_ctrl(priv, m, seq->ns++); 1493 1494 /* callout_deactivate() is not needed here 1495 as ng_callout() is getting called each time */ 1496 1497 /* Sanity check */ 1498 L2TP_SEQ_CHECK(seq); 1499} 1500 1501/* 1502 * Transmit a control stream packet, payload optional. 1503 * The transmit sequence number is not incremented. 1504 */ 1505static int 1506ng_l2tp_xmit_ctrl(priv_p priv, struct mbuf *m, u_int16_t ns) 1507{ 1508 struct l2tp_seq *const seq = &priv->seq; 1509 u_int16_t session_id = 0; 1510 int error; 1511 1512 mtx_lock(&seq->mtx); 1513 1514 /* Stop ack timer: we're sending an ack with this packet. 1515 Doing this before to keep state predictable after error. */ 1516 if (callout_active(&seq->xack_timer)) 1517 ng_uncallout(&seq->xack_timer, priv->node); 1518 1519 seq->xack = seq->nr; 1520 1521 mtx_unlock(&seq->mtx); 1522 1523 /* If no mbuf passed, send an empty packet (ZLB) */ 1524 if (m == NULL) { 1525 1526 /* Create a new mbuf for ZLB packet */ 1527 MGETHDR(m, M_DONTWAIT, MT_DATA); 1528 if (m == NULL) { 1529 priv->stats.memoryFailures++; 1530 return (ENOBUFS); 1531 } 1532 m->m_len = m->m_pkthdr.len = 12; 1533 m->m_pkthdr.rcvif = NULL; 1534 priv->stats.xmitZLBs++; 1535 } else { 1536 1537 /* Strip off session ID */ 1538 if (m->m_len < 2 && (m = m_pullup(m, 2)) == NULL) { 1539 priv->stats.memoryFailures++; 1540 return (ENOBUFS); 1541 } 1542 memcpy(&session_id, mtod(m, u_int16_t *), 2); 1543 m_adj(m, 2); 1544 1545 /* Make room for L2TP header */ 1546 M_PREPEND(m, 12, M_DONTWAIT); 1547 if (m == NULL) { 1548 priv->stats.memoryFailures++; 1549 return (ENOBUFS); 1550 } 1551 } 1552 1553 /* Fill in L2TP header */ 1554 mtod(m, u_int16_t *)[0] = htons(L2TP_CTRL_HDR); 1555 mtod(m, u_int16_t *)[1] = htons(m->m_pkthdr.len); 1556 mtod(m, u_int16_t *)[2] = priv->conf.peer_id; 1557 mtod(m, u_int16_t *)[3] = session_id; 1558 mtod(m, u_int16_t *)[4] = htons(ns); 1559 mtod(m, u_int16_t *)[5] = htons(seq->nr); 1560 1561 /* Update sequence number info and stats */ 1562 priv->stats.xmitPackets++; 1563 priv->stats.xmitOctets += m->m_pkthdr.len; 1564 1565 /* Send packet */ 1566 NG_SEND_DATA_ONLY(error, priv->lower, m); 1567 return (error); 1568} 1569 1570#ifdef INVARIANTS 1571/* 1572 * Sanity check sequence number state. 1573 */ 1574static void 1575ng_l2tp_seq_check(struct l2tp_seq *seq) 1576{ 1577 int self_unack, peer_unack; 1578 int i; 1579 1580#define CHECK(p) KASSERT((p), ("%s: not: %s", __func__, #p)) 1581 1582 mtx_lock(&seq->mtx); 1583 1584 self_unack = L2TP_SEQ_DIFF(seq->nr, seq->xack); 1585 peer_unack = L2TP_SEQ_DIFF(seq->ns, seq->rack); 1586 CHECK(seq->wmax <= L2TP_MAX_XWIN); 1587 CHECK(seq->cwnd >= 1); 1588 CHECK(seq->cwnd <= seq->wmax); 1589 CHECK(seq->ssth >= 1); 1590 CHECK(seq->ssth <= seq->wmax); 1591 if (seq->cwnd < seq->ssth) 1592 CHECK(seq->acks == 0); 1593 else 1594 CHECK(seq->acks <= seq->cwnd); 1595 CHECK(self_unack >= 0); 1596 CHECK(peer_unack >= 0); 1597 CHECK(peer_unack <= seq->wmax); 1598 CHECK((self_unack == 0) ^ callout_active(&seq->xack_timer)); 1599 CHECK((peer_unack == 0) ^ callout_active(&seq->rack_timer)); 1600 for (i = 0; i < peer_unack; i++) 1601 CHECK(seq->xwin[i] != NULL); 1602 for ( ; i < seq->cwnd; i++) /* verify peer's recv window full */ 1603 CHECK(seq->xwin[i] == NULL); 1604 1605 mtx_unlock(&seq->mtx); 1606 1607#undef CHECK 1608} 1609#endif /* INVARIANTS */ 1610