1 2 /* 3 * ng_pptpgre.c 4 * 5 * Copyright (c) 1996-1999 Whistle Communications, Inc. 6 * All rights reserved. 7 * 8 * Subject to the following obligations and disclaimer of warranty, use and 9 * redistribution of this software, in source or object code forms, with or 10 * without modifications are expressly permitted by Whistle Communications; 11 * provided, however, that: 12 * 1. Any and all reproductions of the source or object code must include the 13 * copyright notice above and the following disclaimer of warranties; and 14 * 2. No rights are granted, in any manner or form, to use Whistle 15 * Communications, Inc. trademarks, including the mark "WHISTLE 16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as 17 * such appears in the above copyright notice or in the software. 18 * 19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND 20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO 21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE, 22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF 23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. 24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY 25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS 26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE. 27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES 28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING 29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR 31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY 35 * OF SUCH DAMAGE. 36 * 37 * Author: Archie Cobbs <archie@freebsd.org> 38 * 39 * $FreeBSD$ 40 * $Whistle: ng_pptpgre.c,v 1.7 1999/12/08 00:10:06 archie Exp $ 41 */ 42 43 /* 44 * PPTP/GRE netgraph node type. 45 * 46 * This node type does the GRE encapsulation as specified for the PPTP 47 * protocol (RFC 2637, section 4). This includes sequencing and 48 * retransmission of frames, but not the actual packet delivery nor 49 * any of the TCP control stream protocol. 50 * 51 * The "upper" hook of this node is suitable for attaching to a "ppp" 52 * node link hook. The "lower" hook of this node is suitable for attaching 53 * to a "ksocket" node on hook "inet/raw/gre". 54 */ 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/kernel.h> 59 #include <sys/time.h> 60 #include <sys/mbuf.h> 61 #include <sys/malloc.h> 62 #include <sys/errno.h> 63 64 #include <netinet/in.h> 65 #include <netinet/in_systm.h> 66 #include <netinet/ip.h> 67 68 #include <netgraph/ng_message.h> 69 #include <netgraph/netgraph.h> 70 #include <netgraph/ng_parse.h> 71 #include <netgraph/ng_pptpgre.h> 72 73 /* GRE packet format, as used by PPTP */ 74 struct greheader { 75 #if BYTE_ORDER == LITTLE_ENDIAN 76 u_char recursion:3; /* recursion control */ 77 u_char ssr:1; /* strict source route */ 78 u_char hasSeq:1; /* sequence number present */ 79 u_char hasKey:1; /* key present */ 80 u_char hasRoute:1; /* routing present */ 81 u_char hasSum:1; /* checksum present */ 82 u_char vers:3; /* version */ 83 u_char flags:4; /* flags */ 84 u_char hasAck:1; /* acknowlege number present */ 85 #elif BYTE_ORDER == BIG_ENDIAN 86 u_char hasSum:1; /* checksum present */ 87 u_char hasRoute:1; /* routing present */ 88 u_char hasKey:1; /* key present */ 89 u_char hasSeq:1; /* sequence number present */ 90 u_char ssr:1; /* strict source route */ 91 u_char recursion:3; /* recursion control */ 92 u_char hasAck:1; /* acknowlege number present */ 93 u_char flags:4; /* flags */ 94 u_char vers:3; /* version */ 95 #else 96 #error BYTE_ORDER is not defined properly 97 #endif 98 u_int16_t proto; /* protocol (ethertype) */ 99 u_int16_t length; /* payload length */ 100 u_int16_t cid; /* call id */ 101 u_int32_t data[0]; /* opt. seq, ack, then data */ 102 }; 103 104 /* The PPTP protocol ID used in the GRE 'proto' field */ 105 #define PPTP_GRE_PROTO 0x880b 106 107 /* Bits that must be set a certain way in all PPTP/GRE packets */ 108 #define PPTP_INIT_VALUE ((0x2001 << 16) | PPTP_GRE_PROTO) 109 #define PPTP_INIT_MASK 0xef7fffff 110 111 /* Min and max packet length */ 112 #define PPTP_MAX_PAYLOAD (0xffff - sizeof(struct greheader) - 8) 113 114 /* All times are scaled by this (PPTP_TIME_SCALE time units = 1 sec.) */ 115 #define PPTP_TIME_SCALE 1000 /* milliseconds */ 116 typedef u_int64_t pptptime_t; 117 118 /* Acknowledgment timeout parameters and functions */ 119 #define PPTP_XMIT_WIN 16 /* max xmit window */ 120 #define PPTP_MIN_RTT (PPTP_TIME_SCALE / 10) /* 100 milliseconds */ 121 #define PPTP_MIN_TIMEOUT (PPTP_TIME_SCALE / 83) /* 12 milliseconds */ 122 #define PPTP_MAX_TIMEOUT (10 * PPTP_TIME_SCALE) /* 10 seconds */ 123 124 /* When we recieve a packet, we wait to see if there's an outgoing packet 125 we can piggy-back the ACK off of. These parameters determine the mimimum 126 and maxmimum length of time we're willing to wait in order to do that. 127 These have no effect unless "enableDelayedAck" is turned on. */ 128 #define PPTP_MIN_ACK_DELAY (PPTP_TIME_SCALE / 500) /* 2 milliseconds */ 129 #define PPTP_MAX_ACK_DELAY (PPTP_TIME_SCALE / 2) /* 500 milliseconds */ 130 131 /* See RFC 2637 section 4.4 */ 132 #define PPTP_ACK_ALPHA(x) ((x) >> 3) /* alpha = 0.125 */ 133 #define PPTP_ACK_BETA(x) ((x) >> 2) /* beta = 0.25 */ 134 #define PPTP_ACK_CHI(x) ((x) << 2) /* chi = 4 */ 135 #define PPTP_ACK_DELTA(x) ((x) << 1) /* delta = 2 */ 136 137 #define PPTP_SEQ_DIFF(x,y) ((int32_t)(x) - (int32_t)(y)) 138 139 /* We keep packet retransmit and acknowlegement state in this struct */ 140 struct ng_pptpgre_ackp { 141 int32_t ato; /* adaptive time-out value */ 142 int32_t rtt; /* round trip time estimate */ 143 int32_t dev; /* deviation estimate */ 144 u_int16_t xmitWin; /* size of xmit window */ 145 struct callout sackTimer; /* send ack timer */ 146 struct callout rackTimer; /* recv ack timer */ 147 node_p *sackTimerPtr; /* send ack timer pointer */ 148 node_p *rackTimerPtr; /* recv ack timer pointer */ 149 u_int32_t winAck; /* seq when xmitWin will grow */ 150 pptptime_t timeSent[PPTP_XMIT_WIN]; 151 #ifdef DEBUG_RAT 152 pptptime_t timerStart; /* when rackTimer started */ 153 pptptime_t timerLength; /* rackTimer duration */ 154 #endif 155 }; 156 157 /* Node private data */ 158 struct ng_pptpgre_private { 159 hook_p upper; /* hook to upper layers */ 160 hook_p lower; /* hook to lower layers */ 161 struct ng_pptpgre_conf conf; /* configuration info */ 162 struct ng_pptpgre_ackp ackp; /* packet transmit ack state */ 163 u_int32_t recvSeq; /* last seq # we rcv'd */ 164 u_int32_t xmitSeq; /* last seq # we sent */ 165 u_int32_t recvAck; /* last seq # peer ack'd */ 166 u_int32_t xmitAck; /* last seq # we ack'd */ 167 u_int timers; /* number of pending timers */ 168 struct timeval startTime; /* time node was created */ 169 struct ng_pptpgre_stats stats; /* node statistics */ 170 }; 171 typedef struct ng_pptpgre_private *priv_p; 172 173 /* Netgraph node methods */ 174 static ng_constructor_t ng_pptpgre_constructor; 175 static ng_rcvmsg_t ng_pptpgre_rcvmsg; 176 static ng_shutdown_t ng_pptpgre_shutdown; 177 static ng_newhook_t ng_pptpgre_newhook; 178 static ng_rcvdata_t ng_pptpgre_rcvdata; 179 static ng_disconnect_t ng_pptpgre_disconnect; 180 181 /* Helper functions */ 182 static int ng_pptpgre_xmit(node_p node, item_p item); 183 static int ng_pptpgre_recv(node_p node, item_p item); 184 static void ng_pptpgre_start_send_ack_timer(node_p node, int ackTimeout); 185 static void ng_pptpgre_stop_send_ack_timer(node_p node); 186 static void ng_pptpgre_start_recv_ack_timer(node_p node); 187 static void ng_pptpgre_stop_recv_ack_timer(node_p node); 188 static void ng_pptpgre_recv_ack_timeout(void *arg); 189 static void ng_pptpgre_send_ack_timeout(void *arg); 190 static void ng_pptpgre_reset(node_p node); 191 static pptptime_t ng_pptpgre_time(node_p node); 192 193 /* Parse type for struct ng_pptpgre_conf */ 194 static const struct ng_parse_struct_field ng_pptpgre_conf_type_fields[] 195 = NG_PPTPGRE_CONF_TYPE_INFO; 196 static const struct ng_parse_type ng_pptpgre_conf_type = { 197 &ng_parse_struct_type, 198 &ng_pptpgre_conf_type_fields, 199 }; 200 201 /* Parse type for struct ng_pptpgre_stats */ 202 static const struct ng_parse_struct_field ng_pptpgre_stats_type_fields[] 203 = NG_PPTPGRE_STATS_TYPE_INFO; 204 static const struct ng_parse_type ng_pptp_stats_type = { 205 &ng_parse_struct_type, 206 &ng_pptpgre_stats_type_fields 207 }; 208 209 /* List of commands and how to convert arguments to/from ASCII */ 210 static const struct ng_cmdlist ng_pptpgre_cmdlist[] = { 211 { 212 NGM_PPTPGRE_COOKIE, 213 NGM_PPTPGRE_SET_CONFIG, 214 "setconfig", 215 &ng_pptpgre_conf_type, 216 NULL 217 }, 218 { 219 NGM_PPTPGRE_COOKIE, 220 NGM_PPTPGRE_GET_CONFIG, 221 "getconfig", 222 NULL, 223 &ng_pptpgre_conf_type 224 }, 225 { 226 NGM_PPTPGRE_COOKIE, 227 NGM_PPTPGRE_GET_STATS, 228 "getstats", 229 NULL, 230 &ng_pptp_stats_type 231 }, 232 { 233 NGM_PPTPGRE_COOKIE, 234 NGM_PPTPGRE_CLR_STATS, 235 "clrstats", 236 NULL, 237 NULL 238 }, 239 { 240 NGM_PPTPGRE_COOKIE, 241 NGM_PPTPGRE_GETCLR_STATS, 242 "getclrstats", 243 NULL, 244 &ng_pptp_stats_type 245 }, 246 { 0 } 247 }; 248 249 /* Node type descriptor */ 250 static struct ng_type ng_pptpgre_typestruct = { 251 NG_ABI_VERSION, 252 NG_PPTPGRE_NODE_TYPE, 253 NULL, 254 ng_pptpgre_constructor, 255 ng_pptpgre_rcvmsg, 256 ng_pptpgre_shutdown, 257 ng_pptpgre_newhook, 258 NULL, 259 NULL, 260 ng_pptpgre_rcvdata, 261 ng_pptpgre_disconnect, 262 ng_pptpgre_cmdlist 263 }; 264 NETGRAPH_INIT(pptpgre, &ng_pptpgre_typestruct); 265 266 #define ERROUT(x) do { error = (x); goto done; } while (0) 267 268 /************************************************************************ 269 NETGRAPH NODE STUFF 270 ************************************************************************/ 271 272 /* 273 * Node type constructor 274 */ 275 static int 276 ng_pptpgre_constructor(node_p node) 277 { 278 priv_p priv; 279 280 /* Allocate private structure */ 281 MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO); 282 if (priv == NULL) 283 return (ENOMEM); 284 285 NG_NODE_SET_PRIVATE(node, priv); 286 287 /* Initialize state */ 288 callout_init(&priv->ackp.sackTimer, 0); 289 callout_init(&priv->ackp.rackTimer, 0); 290 291 /* Done */ 292 return (0); 293 } 294 295 /* 296 * Give our OK for a hook to be added. 297 */ 298 static int 299 ng_pptpgre_newhook(node_p node, hook_p hook, const char *name) 300 { 301 const priv_p priv = NG_NODE_PRIVATE(node); 302 hook_p *hookPtr; 303 304 /* Check hook name */ 305 if (strcmp(name, NG_PPTPGRE_HOOK_UPPER) == 0) 306 hookPtr = &priv->upper; 307 else if (strcmp(name, NG_PPTPGRE_HOOK_LOWER) == 0) 308 hookPtr = &priv->lower; 309 else 310 return (EINVAL); 311 312 /* See if already connected */ 313 if (*hookPtr != NULL) 314 return (EISCONN); 315 316 /* OK */ 317 *hookPtr = hook; 318 return (0); 319 } 320 321 /* 322 * Receive a control message. 323 */ 324 static int 325 ng_pptpgre_rcvmsg(node_p node, item_p item, hook_p lasthook) 326 { 327 const priv_p priv = NG_NODE_PRIVATE(node); 328 struct ng_mesg *resp = NULL; 329 int error = 0; 330 struct ng_mesg *msg; 331 332 NGI_GET_MSG(item, msg); 333 switch (msg->header.typecookie) { 334 case NGM_PPTPGRE_COOKIE: 335 switch (msg->header.cmd) { 336 case NGM_PPTPGRE_SET_CONFIG: 337 { 338 struct ng_pptpgre_conf *const newConf = 339 (struct ng_pptpgre_conf *) msg->data; 340 341 /* Check for invalid or illegal config */ 342 if (msg->header.arglen != sizeof(*newConf)) 343 ERROUT(EINVAL); 344 ng_pptpgre_reset(node); /* reset on configure */ 345 priv->conf = *newConf; 346 break; 347 } 348 case NGM_PPTPGRE_GET_CONFIG: 349 NG_MKRESPONSE(resp, msg, sizeof(priv->conf), M_NOWAIT); 350 if (resp == NULL) 351 ERROUT(ENOMEM); 352 bcopy(&priv->conf, resp->data, sizeof(priv->conf)); 353 break; 354 case NGM_PPTPGRE_GET_STATS: 355 case NGM_PPTPGRE_CLR_STATS: 356 case NGM_PPTPGRE_GETCLR_STATS: 357 { 358 if (msg->header.cmd != NGM_PPTPGRE_CLR_STATS) { 359 NG_MKRESPONSE(resp, msg, 360 sizeof(priv->stats), M_NOWAIT); 361 if (resp == NULL) 362 ERROUT(ENOMEM); 363 bcopy(&priv->stats, 364 resp->data, sizeof(priv->stats)); 365 } 366 if (msg->header.cmd != NGM_PPTPGRE_GET_STATS) 367 bzero(&priv->stats, sizeof(priv->stats)); 368 break; 369 } 370 default: 371 error = EINVAL; 372 break; 373 } 374 break; 375 default: 376 error = EINVAL; 377 break; 378 } 379 done: 380 NG_RESPOND_MSG(error, node, item, resp); 381 NG_FREE_MSG(msg); 382 return (error); 383 } 384 385 /* 386 * Receive incoming data on a hook. 387 */ 388 static int 389 ng_pptpgre_rcvdata(hook_p hook, item_p item) 390 { 391 const node_p node = NG_HOOK_NODE(hook); 392 const priv_p priv = NG_NODE_PRIVATE(node); 393 394 /* If not configured, reject */ 395 if (!priv->conf.enabled) { 396 NG_FREE_ITEM(item); 397 return (ENXIO); 398 } 399 400 /* Treat as xmit or recv data */ 401 if (hook == priv->upper) 402 return ng_pptpgre_xmit(node, item); 403 if (hook == priv->lower) 404 return ng_pptpgre_recv(node, item); 405 panic("%s: weird hook", __func__); 406 } 407 408 /* 409 * Destroy node 410 */ 411 static int 412 ng_pptpgre_shutdown(node_p node) 413 { 414 const priv_p priv = NG_NODE_PRIVATE(node); 415 416 /* Reset node */ 417 ng_pptpgre_reset(node); 418 419 /* If no timers remain, free private info as well */ 420 if (priv->timers == 0) { 421 bzero(priv, sizeof(*priv)); 422 FREE(priv, M_NETGRAPH); 423 NG_NODE_SET_PRIVATE(node, NULL); 424 } 425 426 /* Decrement ref count */ 427 NG_NODE_UNREF(node); 428 return (0); 429 } 430 431 /* 432 * Hook disconnection 433 */ 434 static int 435 ng_pptpgre_disconnect(hook_p hook) 436 { 437 const node_p node = NG_HOOK_NODE(hook); 438 const priv_p priv = NG_NODE_PRIVATE(node); 439 440 /* Zero out hook pointer */ 441 if (hook == priv->upper) 442 priv->upper = NULL; 443 else if (hook == priv->lower) 444 priv->lower = NULL; 445 else 446 panic("%s: unknown hook", __func__); 447 448 /* Go away if no longer connected to anything */ 449 if ((NG_NODE_NUMHOOKS(node) == 0) 450 && (NG_NODE_IS_VALID(node))) 451 ng_rmnode_self(node); 452 return (0); 453 } 454 455 /************************************************************************* 456 TRANSMIT AND RECEIVE FUNCTIONS 457 *************************************************************************/ 458 459 /* 460 * Transmit an outgoing frame, or just an ack if m is NULL. 461 */ 462 static int 463 ng_pptpgre_xmit(node_p node, item_p item) 464 { 465 const priv_p priv = NG_NODE_PRIVATE(node); 466 struct ng_pptpgre_ackp *const a = &priv->ackp; 467 u_char buf[sizeof(struct greheader) + 2 * sizeof(u_int32_t)]; 468 struct greheader *const gre = (struct greheader *)buf; 469 int grelen, error; 470 struct mbuf *m; 471 472 if (item) { 473 NGI_GET_M(item, m); 474 } else { 475 m = NULL; 476 } 477 /* Check if there's data */ 478 if (m != NULL) { 479 480 /* Is our transmit window full? */ 481 if ((u_int32_t)PPTP_SEQ_DIFF(priv->xmitSeq, priv->recvAck) 482 >= a->xmitWin) { 483 priv->stats.xmitDrops++; 484 NG_FREE_M(m); 485 NG_FREE_ITEM(item); 486 return (ENOBUFS); 487 } 488 489 /* Sanity check frame length */ 490 if (m != NULL && m->m_pkthdr.len > PPTP_MAX_PAYLOAD) { 491 priv->stats.xmitTooBig++; 492 NG_FREE_M(m); 493 NG_FREE_ITEM(item); 494 return (EMSGSIZE); 495 } 496 } else { 497 priv->stats.xmitLoneAcks++; 498 } 499 500 /* Build GRE header */ 501 ((u_int32_t *)gre)[0] = htonl(PPTP_INIT_VALUE); 502 gre->length = (m != NULL) ? htons((u_short)m->m_pkthdr.len) : 0; 503 gre->cid = htons(priv->conf.peerCid); 504 505 /* Include sequence number if packet contains any data */ 506 if (m != NULL) { 507 gre->hasSeq = 1; 508 a->timeSent[priv->xmitSeq - priv->recvAck] 509 = ng_pptpgre_time(node); 510 priv->xmitSeq++; 511 gre->data[0] = htonl(priv->xmitSeq); 512 } 513 514 /* Include acknowledgement (and stop send ack timer) if needed */ 515 if (priv->conf.enableAlwaysAck || priv->xmitAck != priv->recvSeq) { 516 gre->hasAck = 1; 517 gre->data[gre->hasSeq] = htonl(priv->recvSeq); 518 priv->xmitAck = priv->recvSeq; 519 ng_pptpgre_stop_send_ack_timer(node); 520 } 521 522 /* Prepend GRE header to outgoing frame */ 523 grelen = sizeof(*gre) + sizeof(u_int32_t) * (gre->hasSeq + gre->hasAck); 524 if (m == NULL) { 525 MGETHDR(m, M_DONTWAIT, MT_DATA); 526 if (m == NULL) { 527 priv->stats.memoryFailures++; 528 if (item) 529 NG_FREE_ITEM(item); 530 return (ENOBUFS); 531 } 532 m->m_len = m->m_pkthdr.len = grelen; 533 m->m_pkthdr.rcvif = NULL; 534 } else { 535 M_PREPEND(m, grelen, M_NOWAIT); 536 if (m == NULL || (m->m_len < grelen 537 && (m = m_pullup(m, grelen)) == NULL)) { 538 priv->stats.memoryFailures++; 539 if (item) 540 NG_FREE_ITEM(item); 541 return (ENOBUFS); 542 } 543 } 544 bcopy(gre, mtod(m, u_char *), grelen); 545 546 /* Update stats */ 547 priv->stats.xmitPackets++; 548 priv->stats.xmitOctets += m->m_pkthdr.len; 549 550 /* Deliver packet */ 551 if (item) { 552 NG_FWD_NEW_DATA(error, item, priv->lower, m); 553 } else { 554 NG_SEND_DATA_ONLY(error, priv->lower, m); 555 } 556 557 558 /* Start receive ACK timer if data was sent and not already running */ 559 if (error == 0 && gre->hasSeq && priv->xmitSeq == priv->recvAck + 1) 560 ng_pptpgre_start_recv_ack_timer(node); 561 return (error); 562 } 563 564 /* 565 * Handle an incoming packet. The packet includes the IP header. 566 */ 567 static int 568 ng_pptpgre_recv(node_p node, item_p item) 569 { 570 const priv_p priv = NG_NODE_PRIVATE(node); 571 int iphlen, grelen, extralen; 572 const struct greheader *gre; 573 const struct ip *ip; 574 int error = 0; 575 struct mbuf *m; 576 577 NGI_GET_M(item, m); 578 /* Update stats */ 579 priv->stats.recvPackets++; 580 priv->stats.recvOctets += m->m_pkthdr.len; 581 582 /* Sanity check packet length */ 583 if (m->m_pkthdr.len < sizeof(*ip) + sizeof(*gre)) { 584 priv->stats.recvRunts++; 585 bad: 586 NG_FREE_M(m); 587 NG_FREE_ITEM(item); 588 return (EINVAL); 589 } 590 591 /* Safely pull up the complete IP+GRE headers */ 592 if (m->m_len < sizeof(*ip) + sizeof(*gre) 593 && (m = m_pullup(m, sizeof(*ip) + sizeof(*gre))) == NULL) { 594 priv->stats.memoryFailures++; 595 NG_FREE_ITEM(item); 596 return (ENOBUFS); 597 } 598 ip = mtod(m, const struct ip *); 599 iphlen = ip->ip_hl << 2; 600 if (m->m_len < iphlen + sizeof(*gre)) { 601 if ((m = m_pullup(m, iphlen + sizeof(*gre))) == NULL) { 602 priv->stats.memoryFailures++; 603 NG_FREE_ITEM(item); 604 return (ENOBUFS); 605 } 606 ip = mtod(m, const struct ip *); 607 } 608 gre = (const struct greheader *)((const u_char *)ip + iphlen); 609 grelen = sizeof(*gre) + sizeof(u_int32_t) * (gre->hasSeq + gre->hasAck); 610 if (m->m_pkthdr.len < iphlen + grelen) { 611 priv->stats.recvRunts++; 612 goto bad; 613 } 614 if (m->m_len < iphlen + grelen) { 615 if ((m = m_pullup(m, iphlen + grelen)) == NULL) { 616 priv->stats.memoryFailures++; 617 NG_FREE_ITEM(item); 618 return (ENOBUFS); 619 } 620 ip = mtod(m, const struct ip *); 621 gre = (const struct greheader *)((const u_char *)ip + iphlen); 622 } 623 624 /* Sanity check packet length and GRE header bits */ 625 extralen = m->m_pkthdr.len 626 - (iphlen + grelen + gre->hasSeq * (u_int16_t)ntohs(gre->length)); 627 if (extralen < 0) { 628 priv->stats.recvBadGRE++; 629 goto bad; 630 } 631 if ((ntohl(*((const u_int32_t *)gre)) & PPTP_INIT_MASK) 632 != PPTP_INIT_VALUE) { 633 priv->stats.recvBadGRE++; 634 goto bad; 635 } 636 if (ntohs(gre->cid) != priv->conf.cid) { 637 priv->stats.recvBadCID++; 638 goto bad; 639 } 640 641 /* Look for peer ack */ 642 if (gre->hasAck) { 643 struct ng_pptpgre_ackp *const a = &priv->ackp; 644 const u_int32_t ack = ntohl(gre->data[gre->hasSeq]); 645 const int index = ack - priv->recvAck - 1; 646 long sample; 647 long diff; 648 649 /* Sanity check ack value */ 650 if (PPTP_SEQ_DIFF(ack, priv->xmitSeq) > 0) { 651 priv->stats.recvBadAcks++; 652 goto badAck; /* we never sent it! */ 653 } 654 if (PPTP_SEQ_DIFF(ack, priv->recvAck) <= 0) 655 goto badAck; /* ack already timed out */ 656 priv->recvAck = ack; 657 658 /* Update adaptive timeout stuff */ 659 sample = ng_pptpgre_time(node) - a->timeSent[index]; 660 diff = sample - a->rtt; 661 a->rtt += PPTP_ACK_ALPHA(diff); 662 if (diff < 0) 663 diff = -diff; 664 a->dev += PPTP_ACK_BETA(diff - a->dev); 665 a->ato = a->rtt + PPTP_ACK_CHI(a->dev); 666 if (a->ato > PPTP_MAX_TIMEOUT) 667 a->ato = PPTP_MAX_TIMEOUT; 668 if (a->ato < PPTP_MIN_TIMEOUT) 669 a->ato = PPTP_MIN_TIMEOUT; 670 671 /* Shift packet transmit times in our transmit window */ 672 ovbcopy(a->timeSent + index + 1, a->timeSent, 673 sizeof(*a->timeSent) * (PPTP_XMIT_WIN - (index + 1))); 674 675 /* If we sent an entire window, increase window size by one */ 676 if (PPTP_SEQ_DIFF(ack, a->winAck) >= 0 677 && a->xmitWin < PPTP_XMIT_WIN) { 678 a->xmitWin++; 679 a->winAck = ack + a->xmitWin; 680 } 681 682 /* Stop/(re)start receive ACK timer as necessary */ 683 ng_pptpgre_stop_recv_ack_timer(node); 684 if (priv->recvAck != priv->xmitSeq) 685 ng_pptpgre_start_recv_ack_timer(node); 686 } 687 badAck: 688 689 /* See if frame contains any data */ 690 if (gre->hasSeq) { 691 struct ng_pptpgre_ackp *const a = &priv->ackp; 692 const u_int32_t seq = ntohl(gre->data[0]); 693 694 /* Sanity check sequence number */ 695 if (PPTP_SEQ_DIFF(seq, priv->recvSeq) <= 0) { 696 if (seq == priv->recvSeq) 697 priv->stats.recvDuplicates++; 698 else 699 priv->stats.recvOutOfOrder++; 700 goto bad; /* out-of-order or dup */ 701 } 702 priv->recvSeq = seq; 703 704 /* We need to acknowledge this packet; do it soon... */ 705 if (a->sackTimerPtr == NULL) { 706 int maxWait; 707 708 /* Take 1/4 of the estimated round trip time */ 709 maxWait = (a->rtt >> 2); 710 711 /* If delayed ACK is disabled, send it now */ 712 if (!priv->conf.enableDelayedAck) /* ack now */ 713 ng_pptpgre_xmit(node, NULL); 714 else { /* ack later */ 715 if (maxWait < PPTP_MIN_ACK_DELAY) 716 maxWait = PPTP_MIN_ACK_DELAY; 717 if (maxWait > PPTP_MAX_ACK_DELAY) 718 maxWait = PPTP_MAX_ACK_DELAY; 719 ng_pptpgre_start_send_ack_timer(node, maxWait); 720 } 721 } 722 723 /* Trim mbuf down to internal payload */ 724 m_adj(m, iphlen + grelen); 725 if (extralen > 0) 726 m_adj(m, -extralen); 727 728 /* Deliver frame to upper layers */ 729 NG_FWD_NEW_DATA(error, item, priv->upper, m); 730 } else { 731 priv->stats.recvLoneAcks++; 732 NG_FREE_ITEM(item); 733 NG_FREE_M(m); /* no data to deliver */ 734 } 735 return (error); 736 } 737 738 /************************************************************************* 739 TIMER RELATED FUNCTIONS 740 *************************************************************************/ 741 742 /* 743 * Start a timer for the peer's acknowledging our oldest unacknowledged 744 * sequence number. If we get an ack for this sequence number before 745 * the timer goes off, we cancel the timer. Resets currently running 746 * recv ack timer, if any. 747 */ 748 static void 749 ng_pptpgre_start_recv_ack_timer(node_p node) 750 { 751 const priv_p priv = NG_NODE_PRIVATE(node); 752 struct ng_pptpgre_ackp *const a = &priv->ackp; 753 int remain, ticks; 754 755 /* Compute how long until oldest unack'd packet times out, 756 and reset the timer to that time. */ 757 KASSERT(a->rackTimerPtr == NULL, ("%s: rackTimer", __func__)); 758 remain = (a->timeSent[0] + a->ato) - ng_pptpgre_time(node); 759 if (remain < 0) 760 remain = 0; 761 #ifdef DEBUG_RAT 762 a->timerLength = remain; 763 a->timerStart = ng_pptpgre_time(node); 764 #endif 765 766 /* Start new timer */ 767 MALLOC(a->rackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT); 768 if (a->rackTimerPtr == NULL) { 769 priv->stats.memoryFailures++; 770 return; /* XXX potential hang here */ 771 } 772 *a->rackTimerPtr = node; /* ensures the correct timeout event */ 773 NG_NODE_REF(node); 774 priv->timers++; 775 776 /* Be conservative: timeout can happen up to 1 tick early */ 777 ticks = (((remain * hz) + PPTP_TIME_SCALE - 1) / PPTP_TIME_SCALE) + 1; 778 callout_reset(&a->rackTimer, ticks, 779 ng_pptpgre_recv_ack_timeout, a->rackTimerPtr); 780 } 781 782 /* 783 * Stop receive ack timer. 784 */ 785 static void 786 ng_pptpgre_stop_recv_ack_timer(node_p node) 787 { 788 const priv_p priv = NG_NODE_PRIVATE(node); 789 struct ng_pptpgre_ackp *const a = &priv->ackp; 790 791 if (callout_stop(&a->rackTimer)) { 792 FREE(a->rackTimerPtr, M_NETGRAPH); 793 priv->timers--; 794 NG_NODE_UNREF(node); 795 } 796 a->rackTimerPtr = NULL; 797 } 798 799 /* 800 * The peer has failed to acknowledge the oldest unacknowledged sequence 801 * number within the time allotted. Update our adaptive timeout parameters 802 * and reset/restart the recv ack timer. 803 */ 804 static void 805 ng_pptpgre_recv_ack_timeout(void *arg) 806 { 807 int s = splnet(); 808 const node_p node = *((node_p *)arg); 809 const priv_p priv = NG_NODE_PRIVATE(node); 810 struct ng_pptpgre_ackp *const a = &priv->ackp; 811 812 /* This complicated stuff is needed to avoid race conditions */ 813 FREE(arg, M_NETGRAPH); 814 KASSERT(node->nd_refs > 0, ("%s: no nd_refs", __func__)); 815 KASSERT(priv != NULL, ("%s: priv=NULL", __func__)); 816 priv->timers--; 817 if (NG_NODE_NOT_VALID(node)) { /* shutdown race condition */ 818 if (priv->timers == 0) { 819 FREE(priv, M_NETGRAPH); 820 NG_NODE_SET_PRIVATE(node, NULL); 821 } 822 NG_NODE_UNREF(node); 823 splx(s); 824 return; 825 } 826 if (arg != a->rackTimerPtr) { /* timer stopped race condition */ 827 NG_NODE_UNREF(node); 828 splx(s); 829 return; 830 } 831 a->rackTimerPtr = NULL; 832 833 /* Update adaptive timeout stuff */ 834 priv->stats.recvAckTimeouts++; 835 a->rtt = PPTP_ACK_DELTA(a->rtt); 836 a->ato = a->rtt + PPTP_ACK_CHI(a->dev); 837 if (a->ato > PPTP_MAX_TIMEOUT) 838 a->ato = PPTP_MAX_TIMEOUT; 839 if (a->ato < PPTP_MIN_TIMEOUT) 840 a->ato = PPTP_MIN_TIMEOUT; 841 842 #ifdef DEBUG_RAT 843 log(LOG_DEBUG, 844 "RAT now=%d seq=0x%x sent=%d tstart=%d tlen=%d ato=%d\n", 845 (int)ng_pptpgre_time(node), priv->recvAck + 1, 846 (int)a->timeSent[0], (int)a->timerStart, (int)a->timerLength, a->ato); 847 #endif 848 849 /* Reset ack and sliding window */ 850 priv->recvAck = priv->xmitSeq; /* pretend we got the ack */ 851 a->xmitWin = (a->xmitWin + 1) / 2; /* shrink transmit window */ 852 a->winAck = priv->recvAck + a->xmitWin; /* reset win expand time */ 853 NG_NODE_UNREF(node); 854 splx(s); 855 } 856 857 /* 858 * Start the send ack timer. This assumes the timer is not 859 * already running. 860 */ 861 static void 862 ng_pptpgre_start_send_ack_timer(node_p node, int ackTimeout) 863 { 864 const priv_p priv = NG_NODE_PRIVATE(node); 865 struct ng_pptpgre_ackp *const a = &priv->ackp; 866 int ticks; 867 868 /* Start new timer */ 869 KASSERT(a->sackTimerPtr == NULL, ("%s: sackTimer", __func__)); 870 MALLOC(a->sackTimerPtr, node_p *, sizeof(node_p), M_NETGRAPH, M_NOWAIT); 871 if (a->sackTimerPtr == NULL) { 872 priv->stats.memoryFailures++; 873 return; /* XXX potential hang here */ 874 } 875 *a->sackTimerPtr = node; /* ensures the correct timeout event */ 876 NG_NODE_REF(node); 877 priv->timers++; 878 879 /* Be conservative: timeout can happen up to 1 tick early */ 880 ticks = (((ackTimeout * hz) + PPTP_TIME_SCALE - 1) / PPTP_TIME_SCALE); 881 callout_reset(&a->sackTimer, ticks, 882 ng_pptpgre_send_ack_timeout, a->sackTimerPtr); 883 } 884 885 /* 886 * Stop send ack timer. 887 */ 888 static void 889 ng_pptpgre_stop_send_ack_timer(node_p node) 890 { 891 const priv_p priv = NG_NODE_PRIVATE(node); 892 struct ng_pptpgre_ackp *const a = &priv->ackp; 893 894 if (callout_stop(&a->sackTimer)) { 895 FREE(a->sackTimerPtr, M_NETGRAPH); 896 priv->timers--; 897 NG_NODE_UNREF(node); 898 } 899 a->sackTimerPtr = NULL; 900 } 901 902 /* 903 * We've waited as long as we're willing to wait before sending an 904 * acknowledgement to the peer for received frames. We had hoped to 905 * be able to piggy back our acknowledgement on an outgoing data frame, 906 * but apparently there haven't been any since. So send the ack now. 907 */ 908 static void 909 ng_pptpgre_send_ack_timeout(void *arg) 910 { 911 int s = splnet(); 912 const node_p node = *((node_p *)arg); 913 const priv_p priv = NG_NODE_PRIVATE(node); 914 struct ng_pptpgre_ackp *const a = &priv->ackp; 915 916 /* This complicated stuff is needed to avoid race conditions */ 917 FREE(arg, M_NETGRAPH); 918 KASSERT(node->nd_refs > 0, ("%s: no nd_refs", __func__)); 919 KASSERT(priv != NULL, ("%s: priv=NULL", __func__)); 920 priv->timers--; 921 if (NG_NODE_NOT_VALID(node)) { /* shutdown race condition */ 922 if (priv->timers == 0) { 923 FREE(priv, M_NETGRAPH); 924 NG_NODE_SET_PRIVATE(node, NULL); 925 } 926 NG_NODE_UNREF(node); 927 splx(s); 928 return; 929 } 930 if (a->sackTimerPtr != arg) { /* timer stopped race condition */ 931 NG_NODE_UNREF(node); 932 splx(s); 933 return; 934 } 935 a->sackTimerPtr = NULL; 936 937 /* Send a frame with an ack but no payload */ 938 ng_pptpgre_xmit(node, NULL); 939 NG_NODE_UNREF(node); 940 splx(s); 941 } 942 943 /************************************************************************* 944 MISC FUNCTIONS 945 *************************************************************************/ 946 947 /* 948 * Reset state 949 */ 950 static void 951 ng_pptpgre_reset(node_p node) 952 { 953 const priv_p priv = NG_NODE_PRIVATE(node); 954 struct ng_pptpgre_ackp *const a = &priv->ackp; 955 956 /* Reset adaptive timeout state */ 957 a->ato = PPTP_MAX_TIMEOUT; 958 a->rtt = priv->conf.peerPpd * PPTP_TIME_SCALE / 10; /* ppd in 10ths */ 959 if (a->rtt < PPTP_MIN_RTT) 960 a->rtt = PPTP_MIN_RTT; 961 a->dev = 0; 962 a->xmitWin = (priv->conf.recvWin + 1) / 2; 963 if (a->xmitWin < 2) /* often the first packet is lost */ 964 a->xmitWin = 2; /* because the peer isn't ready */ 965 if (a->xmitWin > PPTP_XMIT_WIN) 966 a->xmitWin = PPTP_XMIT_WIN; 967 a->winAck = a->xmitWin; 968 969 /* Reset sequence numbers */ 970 priv->recvSeq = ~0; 971 priv->recvAck = ~0; 972 priv->xmitSeq = ~0; 973 priv->xmitAck = ~0; 974 975 /* Reset start time */ 976 getmicrouptime(&priv->startTime); 977 978 /* Reset stats */ 979 bzero(&priv->stats, sizeof(priv->stats)); 980 981 /* Stop timers */ 982 ng_pptpgre_stop_send_ack_timer(node); 983 ng_pptpgre_stop_recv_ack_timer(node); 984 } 985 986 /* 987 * Return the current time scaled & translated to our internally used format. 988 */ 989 static pptptime_t 990 ng_pptpgre_time(node_p node) 991 { 992 const priv_p priv = NG_NODE_PRIVATE(node); 993 struct timeval tv; 994 pptptime_t t; 995 996 microuptime(&tv); 997 if (tv.tv_sec < priv->startTime.tv_sec 998 || (tv.tv_sec == priv->startTime.tv_sec 999 && tv.tv_usec < priv->startTime.tv_usec)) 1000 return (0); 1001 timevalsub(&tv, &priv->startTime); 1002 t = (pptptime_t)tv.tv_sec * PPTP_TIME_SCALE; 1003 t += (pptptime_t)tv.tv_usec / (1000000 / PPTP_TIME_SCALE); 1004 return(t); 1005 } 1006 1007