1/* 2 * DCCP connection tracking protocol helper 3 * 4 * Copyright (c) 2005, 2006, 2008 Patrick McHardy <kaber@trash.net> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 */ 11#include <linux/kernel.h> 12#include <linux/module.h> 13#include <linux/init.h> 14#include <linux/sysctl.h> 15#include <linux/spinlock.h> 16#include <linux/skbuff.h> 17#include <linux/dccp.h> 18#include <linux/slab.h> 19 20#include <net/net_namespace.h> 21#include <net/netns/generic.h> 22 23#include <linux/netfilter/nfnetlink_conntrack.h> 24#include <net/netfilter/nf_conntrack.h> 25#include <net/netfilter/nf_conntrack_l4proto.h> 26#include <net/netfilter/nf_conntrack_ecache.h> 27#include <net/netfilter/nf_log.h> 28 29/* Timeouts are based on values from RFC4340: 30 * 31 * - REQUEST: 32 * 33 * 8.1.2. Client Request 34 * 35 * A client MAY give up on its DCCP-Requests after some time 36 * (3 minutes, for example). 37 * 38 * - RESPOND: 39 * 40 * 8.1.3. Server Response 41 * 42 * It MAY also leave the RESPOND state for CLOSED after a timeout of 43 * not less than 4MSL (8 minutes); 44 * 45 * - PARTOPEN: 46 * 47 * 8.1.5. Handshake Completion 48 * 49 * If the client remains in PARTOPEN for more than 4MSL (8 minutes), 50 * it SHOULD reset the connection with Reset Code 2, "Aborted". 51 * 52 * - OPEN: 53 * 54 * The DCCP timestamp overflows after 11.9 hours. If the connection 55 * stays idle this long the sequence number won't be recognized 56 * as valid anymore. 57 * 58 * - CLOSEREQ/CLOSING: 59 * 60 * 8.3. Termination 61 * 62 * The retransmission timer should initially be set to go off in two 63 * round-trip times and should back off to not less than once every 64 * 64 seconds ... 65 * 66 * - TIMEWAIT: 67 * 68 * 4.3. States 69 * 70 * A server or client socket remains in this state for 2MSL (4 minutes) 71 * after the connection has been town down, ... 72 */ 73 74#define DCCP_MSL (2 * 60 * HZ) 75 76static const char * const dccp_state_names[] = { 77 [CT_DCCP_NONE] = "NONE", 78 [CT_DCCP_REQUEST] = "REQUEST", 79 [CT_DCCP_RESPOND] = "RESPOND", 80 [CT_DCCP_PARTOPEN] = "PARTOPEN", 81 [CT_DCCP_OPEN] = "OPEN", 82 [CT_DCCP_CLOSEREQ] = "CLOSEREQ", 83 [CT_DCCP_CLOSING] = "CLOSING", 84 [CT_DCCP_TIMEWAIT] = "TIMEWAIT", 85 [CT_DCCP_IGNORE] = "IGNORE", 86 [CT_DCCP_INVALID] = "INVALID", 87}; 88 89#define sNO CT_DCCP_NONE 90#define sRQ CT_DCCP_REQUEST 91#define sRS CT_DCCP_RESPOND 92#define sPO CT_DCCP_PARTOPEN 93#define sOP CT_DCCP_OPEN 94#define sCR CT_DCCP_CLOSEREQ 95#define sCG CT_DCCP_CLOSING 96#define sTW CT_DCCP_TIMEWAIT 97#define sIG CT_DCCP_IGNORE 98#define sIV CT_DCCP_INVALID 99 100/* 101 * DCCP state transistion table 102 * 103 * The assumption is the same as for TCP tracking: 104 * 105 * We are the man in the middle. All the packets go through us but might 106 * get lost in transit to the destination. It is assumed that the destination 107 * can't receive segments we haven't seen. 108 * 109 * The following states exist: 110 * 111 * NONE: Initial state, expecting Request 112 * REQUEST: Request seen, waiting for Response from server 113 * RESPOND: Response from server seen, waiting for Ack from client 114 * PARTOPEN: Ack after Response seen, waiting for packet other than Response, 115 * Reset or Sync from server 116 * OPEN: Packet other than Response, Reset or Sync seen 117 * CLOSEREQ: CloseReq from server seen, expecting Close from client 118 * CLOSING: Close seen, expecting Reset 119 * TIMEWAIT: Reset seen 120 * IGNORE: Not determinable whether packet is valid 121 * 122 * Some states exist only on one side of the connection: REQUEST, RESPOND, 123 * PARTOPEN, CLOSEREQ. For the other side these states are equivalent to 124 * the one it was in before. 125 * 126 * Packets are marked as ignored (sIG) if we don't know if they're valid 127 * (for example a reincarnation of a connection we didn't notice is dead 128 * already) and the server may send back a connection closing Reset or a 129 * Response. They're also used for Sync/SyncAck packets, which we don't 130 * care about. 131 */ 132static const u_int8_t 133dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] = { 134 [CT_DCCP_ROLE_CLIENT] = { 135 [DCCP_PKT_REQUEST] = { 136 /* 137 * sNO -> sRQ Regular Request 138 * sRQ -> sRQ Retransmitted Request or reincarnation 139 * sRS -> sRS Retransmitted Request (apparently Response 140 * got lost after we saw it) or reincarnation 141 * sPO -> sIG Ignore, conntrack might be out of sync 142 * sOP -> sIG Ignore, conntrack might be out of sync 143 * sCR -> sIG Ignore, conntrack might be out of sync 144 * sCG -> sIG Ignore, conntrack might be out of sync 145 * sTW -> sRQ Reincarnation 146 * 147 * sNO, sRQ, sRS, sPO. sOP, sCR, sCG, sTW, */ 148 sRQ, sRQ, sRS, sIG, sIG, sIG, sIG, sRQ, 149 }, 150 [DCCP_PKT_RESPONSE] = { 151 /* 152 * sNO -> sIV Invalid 153 * sRQ -> sIG Ignore, might be response to ignored Request 154 * sRS -> sIG Ignore, might be response to ignored Request 155 * sPO -> sIG Ignore, might be response to ignored Request 156 * sOP -> sIG Ignore, might be response to ignored Request 157 * sCR -> sIG Ignore, might be response to ignored Request 158 * sCG -> sIG Ignore, might be response to ignored Request 159 * sTW -> sIV Invalid, reincarnation in reverse direction 160 * goes through sRQ 161 * 162 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 163 sIV, sIG, sIG, sIG, sIG, sIG, sIG, sIV, 164 }, 165 [DCCP_PKT_ACK] = { 166 /* 167 * sNO -> sIV No connection 168 * sRQ -> sIV No connection 169 * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) 170 * sPO -> sPO Retransmitted Ack for Response, remain in PARTOPEN 171 * sOP -> sOP Regular ACK, remain in OPEN 172 * sCR -> sCR Ack in CLOSEREQ MAY be processed (8.3.) 173 * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) 174 * sTW -> sIV 175 * 176 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 177 sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV 178 }, 179 [DCCP_PKT_DATA] = { 180 /* 181 * sNO -> sIV No connection 182 * sRQ -> sIV No connection 183 * sRS -> sIV No connection 184 * sPO -> sIV MUST use DataAck in PARTOPEN state (8.1.5.) 185 * sOP -> sOP Regular Data packet 186 * sCR -> sCR Data in CLOSEREQ MAY be processed (8.3.) 187 * sCG -> sCG Data in CLOSING MAY be processed (8.3.) 188 * sTW -> sIV 189 * 190 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 191 sIV, sIV, sIV, sIV, sOP, sCR, sCG, sIV, 192 }, 193 [DCCP_PKT_DATAACK] = { 194 /* 195 * sNO -> sIV No connection 196 * sRQ -> sIV No connection 197 * sRS -> sPO Ack for Response, move to PARTOPEN (8.1.5.) 198 * sPO -> sPO Remain in PARTOPEN state 199 * sOP -> sOP Regular DataAck packet in OPEN state 200 * sCR -> sCR DataAck in CLOSEREQ MAY be processed (8.3.) 201 * sCG -> sCG DataAck in CLOSING MAY be processed (8.3.) 202 * sTW -> sIV 203 * 204 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 205 sIV, sIV, sPO, sPO, sOP, sCR, sCG, sIV 206 }, 207 [DCCP_PKT_CLOSEREQ] = { 208 /* 209 * CLOSEREQ may only be sent by the server. 210 * 211 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 212 sIV, sIV, sIV, sIV, sIV, sIV, sIV, sIV 213 }, 214 [DCCP_PKT_CLOSE] = { 215 /* 216 * sNO -> sIV No connection 217 * sRQ -> sIV No connection 218 * sRS -> sIV No connection 219 * sPO -> sCG Client-initiated close 220 * sOP -> sCG Client-initiated close 221 * sCR -> sCG Close in response to CloseReq (8.3.) 222 * sCG -> sCG Retransmit 223 * sTW -> sIV Late retransmit, already in TIME_WAIT 224 * 225 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 226 sIV, sIV, sIV, sCG, sCG, sCG, sIV, sIV 227 }, 228 [DCCP_PKT_RESET] = { 229 /* 230 * sNO -> sIV No connection 231 * sRQ -> sTW Sync received or timeout, SHOULD send Reset (8.1.1.) 232 * sRS -> sTW Response received without Request 233 * sPO -> sTW Timeout, SHOULD send Reset (8.1.5.) 234 * sOP -> sTW Connection reset 235 * sCR -> sTW Connection reset 236 * sCG -> sTW Connection reset 237 * sTW -> sIG Ignore (don't refresh timer) 238 * 239 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 240 sIV, sTW, sTW, sTW, sTW, sTW, sTW, sIG 241 }, 242 [DCCP_PKT_SYNC] = { 243 /* 244 * We currently ignore Sync packets 245 * 246 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 247 sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, 248 }, 249 [DCCP_PKT_SYNCACK] = { 250 /* 251 * We currently ignore SyncAck packets 252 * 253 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 254 sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, 255 }, 256 }, 257 [CT_DCCP_ROLE_SERVER] = { 258 [DCCP_PKT_REQUEST] = { 259 /* 260 * sNO -> sIV Invalid 261 * sRQ -> sIG Ignore, conntrack might be out of sync 262 * sRS -> sIG Ignore, conntrack might be out of sync 263 * sPO -> sIG Ignore, conntrack might be out of sync 264 * sOP -> sIG Ignore, conntrack might be out of sync 265 * sCR -> sIG Ignore, conntrack might be out of sync 266 * sCG -> sIG Ignore, conntrack might be out of sync 267 * sTW -> sRQ Reincarnation, must reverse roles 268 * 269 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 270 sIV, sIG, sIG, sIG, sIG, sIG, sIG, sRQ 271 }, 272 [DCCP_PKT_RESPONSE] = { 273 /* 274 * sNO -> sIV Response without Request 275 * sRQ -> sRS Response to clients Request 276 * sRS -> sRS Retransmitted Response (8.1.3. SHOULD NOT) 277 * sPO -> sIG Response to an ignored Request or late retransmit 278 * sOP -> sIG Ignore, might be response to ignored Request 279 * sCR -> sIG Ignore, might be response to ignored Request 280 * sCG -> sIG Ignore, might be response to ignored Request 281 * sTW -> sIV Invalid, Request from client in sTW moves to sRQ 282 * 283 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 284 sIV, sRS, sRS, sIG, sIG, sIG, sIG, sIV 285 }, 286 [DCCP_PKT_ACK] = { 287 /* 288 * sNO -> sIV No connection 289 * sRQ -> sIV No connection 290 * sRS -> sIV No connection 291 * sPO -> sOP Enter OPEN state (8.1.5.) 292 * sOP -> sOP Regular Ack in OPEN state 293 * sCR -> sIV Waiting for Close from client 294 * sCG -> sCG Ack in CLOSING MAY be processed (8.3.) 295 * sTW -> sIV 296 * 297 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 298 sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV 299 }, 300 [DCCP_PKT_DATA] = { 301 /* 302 * sNO -> sIV No connection 303 * sRQ -> sIV No connection 304 * sRS -> sIV No connection 305 * sPO -> sOP Enter OPEN state (8.1.5.) 306 * sOP -> sOP Regular Data packet in OPEN state 307 * sCR -> sIV Waiting for Close from client 308 * sCG -> sCG Data in CLOSING MAY be processed (8.3.) 309 * sTW -> sIV 310 * 311 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 312 sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV 313 }, 314 [DCCP_PKT_DATAACK] = { 315 /* 316 * sNO -> sIV No connection 317 * sRQ -> sIV No connection 318 * sRS -> sIV No connection 319 * sPO -> sOP Enter OPEN state (8.1.5.) 320 * sOP -> sOP Regular DataAck in OPEN state 321 * sCR -> sIV Waiting for Close from client 322 * sCG -> sCG Data in CLOSING MAY be processed (8.3.) 323 * sTW -> sIV 324 * 325 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 326 sIV, sIV, sIV, sOP, sOP, sIV, sCG, sIV 327 }, 328 [DCCP_PKT_CLOSEREQ] = { 329 /* 330 * sNO -> sIV No connection 331 * sRQ -> sIV No connection 332 * sRS -> sIV No connection 333 * sPO -> sOP -> sCR Move directly to CLOSEREQ (8.1.5.) 334 * sOP -> sCR CloseReq in OPEN state 335 * sCR -> sCR Retransmit 336 * sCG -> sCR Simultaneous close, client sends another Close 337 * sTW -> sIV Already closed 338 * 339 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 340 sIV, sIV, sIV, sCR, sCR, sCR, sCR, sIV 341 }, 342 [DCCP_PKT_CLOSE] = { 343 /* 344 * sNO -> sIV No connection 345 * sRQ -> sIV No connection 346 * sRS -> sIV No connection 347 * sPO -> sOP -> sCG Move direcly to CLOSING 348 * sOP -> sCG Move to CLOSING 349 * sCR -> sIV Close after CloseReq is invalid 350 * sCG -> sCG Retransmit 351 * sTW -> sIV Already closed 352 * 353 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 354 sIV, sIV, sIV, sCG, sCG, sIV, sCG, sIV 355 }, 356 [DCCP_PKT_RESET] = { 357 /* 358 * sNO -> sIV No connection 359 * sRQ -> sTW Reset in response to Request 360 * sRS -> sTW Timeout, SHOULD send Reset (8.1.3.) 361 * sPO -> sTW Timeout, SHOULD send Reset (8.1.3.) 362 * sOP -> sTW 363 * sCR -> sTW 364 * sCG -> sTW 365 * sTW -> sIG Ignore (don't refresh timer) 366 * 367 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW, sTW */ 368 sIV, sTW, sTW, sTW, sTW, sTW, sTW, sTW, sIG 369 }, 370 [DCCP_PKT_SYNC] = { 371 /* 372 * We currently ignore Sync packets 373 * 374 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 375 sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, 376 }, 377 [DCCP_PKT_SYNCACK] = { 378 /* 379 * We currently ignore SyncAck packets 380 * 381 * sNO, sRQ, sRS, sPO, sOP, sCR, sCG, sTW */ 382 sIG, sIG, sIG, sIG, sIG, sIG, sIG, sIG, 383 }, 384 }, 385}; 386 387/* this module per-net specifics */ 388static int dccp_net_id __read_mostly; 389struct dccp_net { 390 int dccp_loose; 391 unsigned int dccp_timeout[CT_DCCP_MAX + 1]; 392#ifdef CONFIG_SYSCTL 393 struct ctl_table_header *sysctl_header; 394 struct ctl_table *sysctl_table; 395#endif 396}; 397 398static inline struct dccp_net *dccp_pernet(struct net *net) 399{ 400 return net_generic(net, dccp_net_id); 401} 402 403static bool dccp_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff, 404 struct nf_conntrack_tuple *tuple) 405{ 406 struct dccp_hdr _hdr, *dh; 407 408 dh = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr); 409 if (dh == NULL) 410 return false; 411 412 tuple->src.u.dccp.port = dh->dccph_sport; 413 tuple->dst.u.dccp.port = dh->dccph_dport; 414 return true; 415} 416 417static bool dccp_invert_tuple(struct nf_conntrack_tuple *inv, 418 const struct nf_conntrack_tuple *tuple) 419{ 420 inv->src.u.dccp.port = tuple->dst.u.dccp.port; 421 inv->dst.u.dccp.port = tuple->src.u.dccp.port; 422 return true; 423} 424 425static bool dccp_new(struct nf_conn *ct, const struct sk_buff *skb, 426 unsigned int dataoff) 427{ 428 struct net *net = nf_ct_net(ct); 429 struct dccp_net *dn; 430 struct dccp_hdr _dh, *dh; 431 const char *msg; 432 u_int8_t state; 433 434 dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); 435 BUG_ON(dh == NULL); 436 437 state = dccp_state_table[CT_DCCP_ROLE_CLIENT][dh->dccph_type][CT_DCCP_NONE]; 438 switch (state) { 439 default: 440 dn = dccp_pernet(net); 441 if (dn->dccp_loose == 0) { 442 msg = "nf_ct_dccp: not picking up existing connection "; 443 goto out_invalid; 444 } 445 case CT_DCCP_REQUEST: 446 break; 447 case CT_DCCP_INVALID: 448 msg = "nf_ct_dccp: invalid state transition "; 449 goto out_invalid; 450 } 451 452 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; 453 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; 454 ct->proto.dccp.state = CT_DCCP_NONE; 455 return true; 456 457out_invalid: 458 if (LOG_INVALID(net, IPPROTO_DCCP)) 459 nf_log_packet(nf_ct_l3num(ct), 0, skb, NULL, NULL, NULL, msg); 460 return false; 461} 462 463static u64 dccp_ack_seq(const struct dccp_hdr *dh) 464{ 465 const struct dccp_hdr_ack_bits *dhack; 466 467 dhack = (void *)dh + __dccp_basic_hdr_len(dh); 468 return ((u64)ntohs(dhack->dccph_ack_nr_high) << 32) + 469 ntohl(dhack->dccph_ack_nr_low); 470} 471 472static int dccp_packet(struct nf_conn *ct, const struct sk_buff *skb, 473 unsigned int dataoff, enum ip_conntrack_info ctinfo, 474 u_int8_t pf, unsigned int hooknum) 475{ 476 struct net *net = nf_ct_net(ct); 477 struct dccp_net *dn; 478 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); 479 struct dccp_hdr _dh, *dh; 480 u_int8_t type, old_state, new_state; 481 enum ct_dccp_roles role; 482 483 dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); 484 BUG_ON(dh == NULL); 485 type = dh->dccph_type; 486 487 if (type == DCCP_PKT_RESET && 488 !test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 489 /* Tear down connection immediately if only reply is a RESET */ 490 nf_ct_kill_acct(ct, ctinfo, skb); 491 return NF_ACCEPT; 492 } 493 494 spin_lock_bh(&ct->lock); 495 496 role = ct->proto.dccp.role[dir]; 497 old_state = ct->proto.dccp.state; 498 new_state = dccp_state_table[role][type][old_state]; 499 500 switch (new_state) { 501 case CT_DCCP_REQUEST: 502 if (old_state == CT_DCCP_TIMEWAIT && 503 role == CT_DCCP_ROLE_SERVER) { 504 /* Reincarnation in the reverse direction: reopen and 505 * reverse client/server roles. */ 506 ct->proto.dccp.role[dir] = CT_DCCP_ROLE_CLIENT; 507 ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_SERVER; 508 } 509 break; 510 case CT_DCCP_RESPOND: 511 if (old_state == CT_DCCP_REQUEST) 512 ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); 513 break; 514 case CT_DCCP_PARTOPEN: 515 if (old_state == CT_DCCP_RESPOND && 516 type == DCCP_PKT_ACK && 517 dccp_ack_seq(dh) == ct->proto.dccp.handshake_seq) 518 set_bit(IPS_ASSURED_BIT, &ct->status); 519 break; 520 case CT_DCCP_IGNORE: 521 /* 522 * Connection tracking might be out of sync, so we ignore 523 * packets that might establish a new connection and resync 524 * if the server responds with a valid Response. 525 */ 526 if (ct->proto.dccp.last_dir == !dir && 527 ct->proto.dccp.last_pkt == DCCP_PKT_REQUEST && 528 type == DCCP_PKT_RESPONSE) { 529 ct->proto.dccp.role[!dir] = CT_DCCP_ROLE_CLIENT; 530 ct->proto.dccp.role[dir] = CT_DCCP_ROLE_SERVER; 531 ct->proto.dccp.handshake_seq = dccp_hdr_seq(dh); 532 new_state = CT_DCCP_RESPOND; 533 break; 534 } 535 ct->proto.dccp.last_dir = dir; 536 ct->proto.dccp.last_pkt = type; 537 538 spin_unlock_bh(&ct->lock); 539 if (LOG_INVALID(net, IPPROTO_DCCP)) 540 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, 541 "nf_ct_dccp: invalid packet ignored "); 542 return NF_ACCEPT; 543 case CT_DCCP_INVALID: 544 spin_unlock_bh(&ct->lock); 545 if (LOG_INVALID(net, IPPROTO_DCCP)) 546 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, 547 "nf_ct_dccp: invalid state transition "); 548 return -NF_ACCEPT; 549 } 550 551 ct->proto.dccp.last_dir = dir; 552 ct->proto.dccp.last_pkt = type; 553 ct->proto.dccp.state = new_state; 554 spin_unlock_bh(&ct->lock); 555 556 if (new_state != old_state) 557 nf_conntrack_event_cache(IPCT_PROTOINFO, ct); 558 559 dn = dccp_pernet(net); 560 nf_ct_refresh_acct(ct, ctinfo, skb, dn->dccp_timeout[new_state]); 561 562 return NF_ACCEPT; 563} 564 565static int dccp_error(struct net *net, struct nf_conn *tmpl, 566 struct sk_buff *skb, unsigned int dataoff, 567 enum ip_conntrack_info *ctinfo, 568 u_int8_t pf, unsigned int hooknum) 569{ 570 struct dccp_hdr _dh, *dh; 571 unsigned int dccp_len = skb->len - dataoff; 572 unsigned int cscov; 573 const char *msg; 574 575 dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &dh); 576 if (dh == NULL) { 577 msg = "nf_ct_dccp: short packet "; 578 goto out_invalid; 579 } 580 581 if (dh->dccph_doff * 4 < sizeof(struct dccp_hdr) || 582 dh->dccph_doff * 4 > dccp_len) { 583 msg = "nf_ct_dccp: truncated/malformed packet "; 584 goto out_invalid; 585 } 586 587 cscov = dccp_len; 588 if (dh->dccph_cscov) { 589 cscov = (dh->dccph_cscov - 1) * 4; 590 if (cscov > dccp_len) { 591 msg = "nf_ct_dccp: bad checksum coverage "; 592 goto out_invalid; 593 } 594 } 595 596 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING && 597 nf_checksum_partial(skb, hooknum, dataoff, cscov, IPPROTO_DCCP, 598 pf)) { 599 msg = "nf_ct_dccp: bad checksum "; 600 goto out_invalid; 601 } 602 603 if (dh->dccph_type >= DCCP_PKT_INVALID) { 604 msg = "nf_ct_dccp: reserved packet type "; 605 goto out_invalid; 606 } 607 608 return NF_ACCEPT; 609 610out_invalid: 611 if (LOG_INVALID(net, IPPROTO_DCCP)) 612 nf_log_packet(pf, 0, skb, NULL, NULL, NULL, msg); 613 return -NF_ACCEPT; 614} 615 616static int dccp_print_tuple(struct seq_file *s, 617 const struct nf_conntrack_tuple *tuple) 618{ 619 return seq_printf(s, "sport=%hu dport=%hu ", 620 ntohs(tuple->src.u.dccp.port), 621 ntohs(tuple->dst.u.dccp.port)); 622} 623 624static int dccp_print_conntrack(struct seq_file *s, struct nf_conn *ct) 625{ 626 return seq_printf(s, "%s ", dccp_state_names[ct->proto.dccp.state]); 627} 628 629#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 630static int dccp_to_nlattr(struct sk_buff *skb, struct nlattr *nla, 631 struct nf_conn *ct) 632{ 633 struct nlattr *nest_parms; 634 635 spin_lock_bh(&ct->lock); 636 nest_parms = nla_nest_start(skb, CTA_PROTOINFO_DCCP | NLA_F_NESTED); 637 if (!nest_parms) 638 goto nla_put_failure; 639 NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_STATE, ct->proto.dccp.state); 640 NLA_PUT_U8(skb, CTA_PROTOINFO_DCCP_ROLE, 641 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL]); 642 NLA_PUT_BE64(skb, CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ, 643 cpu_to_be64(ct->proto.dccp.handshake_seq)); 644 nla_nest_end(skb, nest_parms); 645 spin_unlock_bh(&ct->lock); 646 return 0; 647 648nla_put_failure: 649 spin_unlock_bh(&ct->lock); 650 return -1; 651} 652 653static const struct nla_policy dccp_nla_policy[CTA_PROTOINFO_DCCP_MAX + 1] = { 654 [CTA_PROTOINFO_DCCP_STATE] = { .type = NLA_U8 }, 655 [CTA_PROTOINFO_DCCP_ROLE] = { .type = NLA_U8 }, 656 [CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ] = { .type = NLA_U64 }, 657}; 658 659static int nlattr_to_dccp(struct nlattr *cda[], struct nf_conn *ct) 660{ 661 struct nlattr *attr = cda[CTA_PROTOINFO_DCCP]; 662 struct nlattr *tb[CTA_PROTOINFO_DCCP_MAX + 1]; 663 int err; 664 665 if (!attr) 666 return 0; 667 668 err = nla_parse_nested(tb, CTA_PROTOINFO_DCCP_MAX, attr, 669 dccp_nla_policy); 670 if (err < 0) 671 return err; 672 673 if (!tb[CTA_PROTOINFO_DCCP_STATE] || 674 !tb[CTA_PROTOINFO_DCCP_ROLE] || 675 nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) > CT_DCCP_ROLE_MAX || 676 nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]) >= CT_DCCP_IGNORE) { 677 return -EINVAL; 678 } 679 680 spin_lock_bh(&ct->lock); 681 ct->proto.dccp.state = nla_get_u8(tb[CTA_PROTOINFO_DCCP_STATE]); 682 if (nla_get_u8(tb[CTA_PROTOINFO_DCCP_ROLE]) == CT_DCCP_ROLE_CLIENT) { 683 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_CLIENT; 684 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_SERVER; 685 } else { 686 ct->proto.dccp.role[IP_CT_DIR_ORIGINAL] = CT_DCCP_ROLE_SERVER; 687 ct->proto.dccp.role[IP_CT_DIR_REPLY] = CT_DCCP_ROLE_CLIENT; 688 } 689 if (tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ]) { 690 ct->proto.dccp.handshake_seq = 691 be64_to_cpu(nla_get_be64(tb[CTA_PROTOINFO_DCCP_HANDSHAKE_SEQ])); 692 } 693 spin_unlock_bh(&ct->lock); 694 return 0; 695} 696 697static int dccp_nlattr_size(void) 698{ 699 return nla_total_size(0) /* CTA_PROTOINFO_DCCP */ 700 + nla_policy_len(dccp_nla_policy, CTA_PROTOINFO_DCCP_MAX + 1); 701} 702#endif 703 704#ifdef CONFIG_SYSCTL 705/* template, data assigned later */ 706static struct ctl_table dccp_sysctl_table[] = { 707 { 708 .procname = "nf_conntrack_dccp_timeout_request", 709 .maxlen = sizeof(unsigned int), 710 .mode = 0644, 711 .proc_handler = proc_dointvec_jiffies, 712 }, 713 { 714 .procname = "nf_conntrack_dccp_timeout_respond", 715 .maxlen = sizeof(unsigned int), 716 .mode = 0644, 717 .proc_handler = proc_dointvec_jiffies, 718 }, 719 { 720 .procname = "nf_conntrack_dccp_timeout_partopen", 721 .maxlen = sizeof(unsigned int), 722 .mode = 0644, 723 .proc_handler = proc_dointvec_jiffies, 724 }, 725 { 726 .procname = "nf_conntrack_dccp_timeout_open", 727 .maxlen = sizeof(unsigned int), 728 .mode = 0644, 729 .proc_handler = proc_dointvec_jiffies, 730 }, 731 { 732 .procname = "nf_conntrack_dccp_timeout_closereq", 733 .maxlen = sizeof(unsigned int), 734 .mode = 0644, 735 .proc_handler = proc_dointvec_jiffies, 736 }, 737 { 738 .procname = "nf_conntrack_dccp_timeout_closing", 739 .maxlen = sizeof(unsigned int), 740 .mode = 0644, 741 .proc_handler = proc_dointvec_jiffies, 742 }, 743 { 744 .procname = "nf_conntrack_dccp_timeout_timewait", 745 .maxlen = sizeof(unsigned int), 746 .mode = 0644, 747 .proc_handler = proc_dointvec_jiffies, 748 }, 749 { 750 .procname = "nf_conntrack_dccp_loose", 751 .maxlen = sizeof(int), 752 .mode = 0644, 753 .proc_handler = proc_dointvec, 754 }, 755 { } 756}; 757#endif /* CONFIG_SYSCTL */ 758 759static struct nf_conntrack_l4proto dccp_proto4 __read_mostly = { 760 .l3proto = AF_INET, 761 .l4proto = IPPROTO_DCCP, 762 .name = "dccp", 763 .pkt_to_tuple = dccp_pkt_to_tuple, 764 .invert_tuple = dccp_invert_tuple, 765 .new = dccp_new, 766 .packet = dccp_packet, 767 .error = dccp_error, 768 .print_tuple = dccp_print_tuple, 769 .print_conntrack = dccp_print_conntrack, 770#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 771 .to_nlattr = dccp_to_nlattr, 772 .nlattr_size = dccp_nlattr_size, 773 .from_nlattr = nlattr_to_dccp, 774 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 775 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 776 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 777 .nla_policy = nf_ct_port_nla_policy, 778#endif 779}; 780 781static struct nf_conntrack_l4proto dccp_proto6 __read_mostly = { 782 .l3proto = AF_INET6, 783 .l4proto = IPPROTO_DCCP, 784 .name = "dccp", 785 .pkt_to_tuple = dccp_pkt_to_tuple, 786 .invert_tuple = dccp_invert_tuple, 787 .new = dccp_new, 788 .packet = dccp_packet, 789 .error = dccp_error, 790 .print_tuple = dccp_print_tuple, 791 .print_conntrack = dccp_print_conntrack, 792#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 793 .to_nlattr = dccp_to_nlattr, 794 .nlattr_size = dccp_nlattr_size, 795 .from_nlattr = nlattr_to_dccp, 796 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr, 797 .nlattr_tuple_size = nf_ct_port_nlattr_tuple_size, 798 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple, 799 .nla_policy = nf_ct_port_nla_policy, 800#endif 801}; 802 803static __net_init int dccp_net_init(struct net *net) 804{ 805 struct dccp_net *dn = dccp_pernet(net); 806 807 /* default values */ 808 dn->dccp_loose = 1; 809 dn->dccp_timeout[CT_DCCP_REQUEST] = 2 * DCCP_MSL; 810 dn->dccp_timeout[CT_DCCP_RESPOND] = 4 * DCCP_MSL; 811 dn->dccp_timeout[CT_DCCP_PARTOPEN] = 4 * DCCP_MSL; 812 dn->dccp_timeout[CT_DCCP_OPEN] = 12 * 3600 * HZ; 813 dn->dccp_timeout[CT_DCCP_CLOSEREQ] = 64 * HZ; 814 dn->dccp_timeout[CT_DCCP_CLOSING] = 64 * HZ; 815 dn->dccp_timeout[CT_DCCP_TIMEWAIT] = 2 * DCCP_MSL; 816 817#ifdef CONFIG_SYSCTL 818 dn->sysctl_table = kmemdup(dccp_sysctl_table, 819 sizeof(dccp_sysctl_table), GFP_KERNEL); 820 if (!dn->sysctl_table) 821 return -ENOMEM; 822 823 dn->sysctl_table[0].data = &dn->dccp_timeout[CT_DCCP_REQUEST]; 824 dn->sysctl_table[1].data = &dn->dccp_timeout[CT_DCCP_RESPOND]; 825 dn->sysctl_table[2].data = &dn->dccp_timeout[CT_DCCP_PARTOPEN]; 826 dn->sysctl_table[3].data = &dn->dccp_timeout[CT_DCCP_OPEN]; 827 dn->sysctl_table[4].data = &dn->dccp_timeout[CT_DCCP_CLOSEREQ]; 828 dn->sysctl_table[5].data = &dn->dccp_timeout[CT_DCCP_CLOSING]; 829 dn->sysctl_table[6].data = &dn->dccp_timeout[CT_DCCP_TIMEWAIT]; 830 dn->sysctl_table[7].data = &dn->dccp_loose; 831 832 dn->sysctl_header = register_net_sysctl_table(net, 833 nf_net_netfilter_sysctl_path, dn->sysctl_table); 834 if (!dn->sysctl_header) { 835 kfree(dn->sysctl_table); 836 return -ENOMEM; 837 } 838#endif 839 840 return 0; 841} 842 843static __net_exit void dccp_net_exit(struct net *net) 844{ 845 struct dccp_net *dn = dccp_pernet(net); 846#ifdef CONFIG_SYSCTL 847 unregister_net_sysctl_table(dn->sysctl_header); 848 kfree(dn->sysctl_table); 849#endif 850} 851 852static struct pernet_operations dccp_net_ops = { 853 .init = dccp_net_init, 854 .exit = dccp_net_exit, 855 .id = &dccp_net_id, 856 .size = sizeof(struct dccp_net), 857}; 858 859static int __init nf_conntrack_proto_dccp_init(void) 860{ 861 int err; 862 863 err = register_pernet_subsys(&dccp_net_ops); 864 if (err < 0) 865 goto err1; 866 867 err = nf_conntrack_l4proto_register(&dccp_proto4); 868 if (err < 0) 869 goto err2; 870 871 err = nf_conntrack_l4proto_register(&dccp_proto6); 872 if (err < 0) 873 goto err3; 874 return 0; 875 876err3: 877 nf_conntrack_l4proto_unregister(&dccp_proto4); 878err2: 879 unregister_pernet_subsys(&dccp_net_ops); 880err1: 881 return err; 882} 883 884static void __exit nf_conntrack_proto_dccp_fini(void) 885{ 886 unregister_pernet_subsys(&dccp_net_ops); 887 nf_conntrack_l4proto_unregister(&dccp_proto6); 888 nf_conntrack_l4proto_unregister(&dccp_proto4); 889} 890 891module_init(nf_conntrack_proto_dccp_init); 892module_exit(nf_conntrack_proto_dccp_fini); 893 894MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 895MODULE_DESCRIPTION("DCCP connection tracking protocol helper"); 896MODULE_LICENSE("GPL"); 897