feat.c revision 19443178fbfbf40db15c86012fc37df1a44ab857
1/* 2 * net/dccp/feat.c 3 * 4 * An implementation of the DCCP protocol 5 * Andrea Bittau <a.bittau@cs.ucl.ac.uk> 6 * 7 * ASSUMPTIONS 8 * ----------- 9 * o All currently known SP features have 1-byte quantities. If in the future 10 * extensions of RFCs 4340..42 define features with item lengths larger than 11 * one byte, a feature-specific extension of the code will be required. 12 * 13 * This program is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU General Public License 15 * as published by the Free Software Foundation; either version 16 * 2 of the License, or (at your option) any later version. 17 */ 18 19#include <linux/module.h> 20 21#include "ccid.h" 22#include "feat.h" 23 24#define DCCP_FEAT_SP_NOAGREE (-123) 25 26int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature, 27 u8 *val, u8 len, gfp_t gfp) 28{ 29 struct dccp_opt_pend *opt; 30 31 dccp_feat_debug(type, feature, *val); 32 33 if (len > 3) { 34 DCCP_WARN("invalid length %d\n", len); 35 return -EINVAL; 36 } 37 /* XXX add further sanity checks */ 38 39 /* check if that feature is already being negotiated */ 40 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 41 /* ok we found a negotiation for this option already */ 42 if (opt->dccpop_feat == feature && opt->dccpop_type == type) { 43 dccp_pr_debug("Replacing old\n"); 44 /* replace */ 45 BUG_ON(opt->dccpop_val == NULL); 46 kfree(opt->dccpop_val); 47 opt->dccpop_val = val; 48 opt->dccpop_len = len; 49 opt->dccpop_conf = 0; 50 return 0; 51 } 52 } 53 54 /* negotiation for a new feature */ 55 opt = kmalloc(sizeof(*opt), gfp); 56 if (opt == NULL) 57 return -ENOMEM; 58 59 opt->dccpop_type = type; 60 opt->dccpop_feat = feature; 61 opt->dccpop_len = len; 62 opt->dccpop_val = val; 63 opt->dccpop_conf = 0; 64 opt->dccpop_sc = NULL; 65 66 BUG_ON(opt->dccpop_val == NULL); 67 68 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending); 69 return 0; 70} 71 72EXPORT_SYMBOL_GPL(dccp_feat_change); 73 74static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr) 75{ 76 struct dccp_sock *dp = dccp_sk(sk); 77 struct dccp_minisock *dmsk = dccp_msk(sk); 78 /* figure out if we are changing our CCID or the peer's */ 79 const int rx = type == DCCPO_CHANGE_R; 80 const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid; 81 struct ccid *new_ccid; 82 83 /* Check if nothing is being changed. */ 84 if (ccid_nr == new_ccid_nr) 85 return 0; 86 87 new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC); 88 if (new_ccid == NULL) 89 return -ENOMEM; 90 91 if (rx) { 92 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk); 93 dp->dccps_hc_rx_ccid = new_ccid; 94 dmsk->dccpms_rx_ccid = new_ccid_nr; 95 } else { 96 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk); 97 dp->dccps_hc_tx_ccid = new_ccid; 98 dmsk->dccpms_tx_ccid = new_ccid_nr; 99 } 100 101 return 0; 102} 103 104static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val) 105{ 106 dccp_feat_debug(type, feat, val); 107 108 switch (feat) { 109 case DCCPF_CCID: 110 return dccp_feat_update_ccid(sk, type, val); 111 default: 112 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n", 113 dccp_feat_typename(type), feat); 114 break; 115 } 116 return 0; 117} 118 119static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt, 120 u8 *rpref, u8 rlen) 121{ 122 struct dccp_sock *dp = dccp_sk(sk); 123 u8 *spref, slen, *res = NULL; 124 int i, j, rc, agree = 1; 125 126 BUG_ON(rpref == NULL); 127 128 /* check if we are the black sheep */ 129 if (dp->dccps_role == DCCP_ROLE_CLIENT) { 130 spref = rpref; 131 slen = rlen; 132 rpref = opt->dccpop_val; 133 rlen = opt->dccpop_len; 134 } else { 135 spref = opt->dccpop_val; 136 slen = opt->dccpop_len; 137 } 138 /* 139 * Now we have server preference list in spref and client preference in 140 * rpref 141 */ 142 BUG_ON(spref == NULL); 143 BUG_ON(rpref == NULL); 144 145 /* FIXME sanity check vals */ 146 147 /* Are values in any order? XXX Lame "algorithm" here */ 148 for (i = 0; i < slen; i++) { 149 for (j = 0; j < rlen; j++) { 150 if (spref[i] == rpref[j]) { 151 res = &spref[i]; 152 break; 153 } 154 } 155 if (res) 156 break; 157 } 158 159 /* we didn't agree on anything */ 160 if (res == NULL) { 161 /* confirm previous value */ 162 switch (opt->dccpop_feat) { 163 case DCCPF_CCID: 164 /* XXX did i get this right? =P */ 165 if (opt->dccpop_type == DCCPO_CHANGE_L) 166 res = &dccp_msk(sk)->dccpms_tx_ccid; 167 else 168 res = &dccp_msk(sk)->dccpms_rx_ccid; 169 break; 170 171 default: 172 DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat); 173 /* XXX implement res */ 174 return -EFAULT; 175 } 176 177 dccp_pr_debug("Don't agree... reconfirming %d\n", *res); 178 agree = 0; /* this is used for mandatory options... */ 179 } 180 181 /* need to put result and our preference list */ 182 rlen = 1 + opt->dccpop_len; 183 rpref = kmalloc(rlen, GFP_ATOMIC); 184 if (rpref == NULL) 185 return -ENOMEM; 186 187 *rpref = *res; 188 memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len); 189 190 /* put it in the "confirm queue" */ 191 if (opt->dccpop_sc == NULL) { 192 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC); 193 if (opt->dccpop_sc == NULL) { 194 kfree(rpref); 195 return -ENOMEM; 196 } 197 } else { 198 /* recycle the confirm slot */ 199 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); 200 kfree(opt->dccpop_sc->dccpoc_val); 201 dccp_pr_debug("recycling confirm slot\n"); 202 } 203 memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc)); 204 205 opt->dccpop_sc->dccpoc_val = rpref; 206 opt->dccpop_sc->dccpoc_len = rlen; 207 208 /* update the option on our side [we are about to send the confirm] */ 209 rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res); 210 if (rc) { 211 kfree(opt->dccpop_sc->dccpoc_val); 212 kfree(opt->dccpop_sc); 213 opt->dccpop_sc = NULL; 214 return rc; 215 } 216 217 dccp_pr_debug("Will confirm %d\n", *rpref); 218 219 /* say we want to change to X but we just got a confirm X, suppress our 220 * change 221 */ 222 if (!opt->dccpop_conf) { 223 if (*opt->dccpop_val == *res) 224 opt->dccpop_conf = 1; 225 dccp_pr_debug("won't ask for change of same feature\n"); 226 } 227 228 return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */ 229} 230 231static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 232{ 233 struct dccp_minisock *dmsk = dccp_msk(sk); 234 struct dccp_opt_pend *opt; 235 int rc = 1; 236 u8 t; 237 238 /* 239 * We received a CHANGE. We gotta match it against our own preference 240 * list. If we got a CHANGE_R it means it's a change for us, so we need 241 * to compare our CHANGE_L list. 242 */ 243 if (type == DCCPO_CHANGE_L) 244 t = DCCPO_CHANGE_R; 245 else 246 t = DCCPO_CHANGE_L; 247 248 /* find our preference list for this feature */ 249 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 250 if (opt->dccpop_type != t || opt->dccpop_feat != feature) 251 continue; 252 253 /* find the winner from the two preference lists */ 254 rc = dccp_feat_reconcile(sk, opt, val, len); 255 break; 256 } 257 258 /* We didn't deal with the change. This can happen if we have no 259 * preference list for the feature. In fact, it just shouldn't 260 * happen---if we understand a feature, we should have a preference list 261 * with at least the default value. 262 */ 263 BUG_ON(rc == 1); 264 265 return rc; 266} 267 268static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 269{ 270 struct dccp_opt_pend *opt; 271 struct dccp_minisock *dmsk = dccp_msk(sk); 272 u8 *copy; 273 int rc; 274 275 /* NN features must be Change L (sec. 6.3.2) */ 276 if (type != DCCPO_CHANGE_L) { 277 dccp_pr_debug("received %s for NN feature %d\n", 278 dccp_feat_typename(type), feature); 279 return -EFAULT; 280 } 281 282 /* XXX sanity check opt val */ 283 284 /* copy option so we can confirm it */ 285 opt = kzalloc(sizeof(*opt), GFP_ATOMIC); 286 if (opt == NULL) 287 return -ENOMEM; 288 289 copy = kmemdup(val, len, GFP_ATOMIC); 290 if (copy == NULL) { 291 kfree(opt); 292 return -ENOMEM; 293 } 294 295 opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */ 296 opt->dccpop_feat = feature; 297 opt->dccpop_val = copy; 298 opt->dccpop_len = len; 299 300 /* change feature */ 301 rc = dccp_feat_update(sk, type, feature, *val); 302 if (rc) { 303 kfree(opt->dccpop_val); 304 kfree(opt); 305 return rc; 306 } 307 308 dccp_feat_debug(type, feature, *copy); 309 310 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); 311 312 return 0; 313} 314 315static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk, 316 u8 type, u8 feature) 317{ 318 /* XXX check if other confirms for that are queued and recycle slot */ 319 struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC); 320 321 if (opt == NULL) { 322 /* XXX what do we do? Ignoring should be fine. It's a change 323 * after all =P 324 */ 325 return; 326 } 327 328 switch (type) { 329 case DCCPO_CHANGE_L: 330 opt->dccpop_type = DCCPO_CONFIRM_R; 331 break; 332 case DCCPO_CHANGE_R: 333 opt->dccpop_type = DCCPO_CONFIRM_L; 334 break; 335 default: 336 DCCP_WARN("invalid type %d\n", type); 337 kfree(opt); 338 return; 339 } 340 opt->dccpop_feat = feature; 341 opt->dccpop_val = NULL; 342 opt->dccpop_len = 0; 343 344 /* change feature */ 345 dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature); 346 347 list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf); 348} 349 350static void dccp_feat_flush_confirm(struct sock *sk) 351{ 352 struct dccp_minisock *dmsk = dccp_msk(sk); 353 /* Check if there is anything to confirm in the first place */ 354 int yes = !list_empty(&dmsk->dccpms_conf); 355 356 if (!yes) { 357 struct dccp_opt_pend *opt; 358 359 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 360 if (opt->dccpop_conf) { 361 yes = 1; 362 break; 363 } 364 } 365 } 366 367 if (!yes) 368 return; 369 370 /* OK there is something to confirm... */ 371 /* XXX check if packet is in flight? Send delayed ack?? */ 372 if (sk->sk_state == DCCP_OPEN) 373 dccp_send_ack(sk); 374} 375 376int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len) 377{ 378 int rc; 379 380 dccp_feat_debug(type, feature, *val); 381 382 /* figure out if it's SP or NN feature */ 383 switch (feature) { 384 /* deal with SP features */ 385 case DCCPF_CCID: 386 rc = dccp_feat_sp(sk, type, feature, val, len); 387 break; 388 389 /* deal with NN features */ 390 case DCCPF_ACK_RATIO: 391 rc = dccp_feat_nn(sk, type, feature, val, len); 392 break; 393 394 /* XXX implement other features */ 395 default: 396 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n", 397 dccp_feat_typename(type), feature); 398 rc = -EFAULT; 399 break; 400 } 401 402 /* check if there were problems changing features */ 403 if (rc) { 404 /* If we don't agree on SP, we sent a confirm for old value. 405 * However we propagate rc to caller in case option was 406 * mandatory 407 */ 408 if (rc != DCCP_FEAT_SP_NOAGREE) 409 dccp_feat_empty_confirm(dccp_msk(sk), type, feature); 410 } 411 412 /* generate the confirm [if required] */ 413 dccp_feat_flush_confirm(sk); 414 415 return rc; 416} 417 418EXPORT_SYMBOL_GPL(dccp_feat_change_recv); 419 420int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature, 421 u8 *val, u8 len) 422{ 423 u8 t; 424 struct dccp_opt_pend *opt; 425 struct dccp_minisock *dmsk = dccp_msk(sk); 426 int found = 0; 427 int all_confirmed = 1; 428 429 dccp_feat_debug(type, feature, *val); 430 431 /* locate our change request */ 432 switch (type) { 433 case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break; 434 case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break; 435 default: DCCP_WARN("invalid type %d\n", type); 436 return 1; 437 438 } 439 /* XXX sanity check feature value */ 440 441 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) { 442 if (!opt->dccpop_conf && opt->dccpop_type == t && 443 opt->dccpop_feat == feature) { 444 found = 1; 445 dccp_pr_debug("feature %d found\n", opt->dccpop_feat); 446 447 /* XXX do sanity check */ 448 449 opt->dccpop_conf = 1; 450 451 /* We got a confirmation---change the option */ 452 dccp_feat_update(sk, opt->dccpop_type, 453 opt->dccpop_feat, *val); 454 455 /* XXX check the return value of dccp_feat_update */ 456 break; 457 } 458 459 if (!opt->dccpop_conf) 460 all_confirmed = 0; 461 } 462 463 /* fix re-transmit timer */ 464 /* XXX gotta make sure that no option negotiation occurs during 465 * connection shutdown. Consider that the CLOSEREQ is sent and timer is 466 * on. if all options are confirmed it might kill timer which should 467 * remain alive until close is received. 468 */ 469 if (all_confirmed) { 470 dccp_pr_debug("clear feat negotiation timer %p\n", sk); 471 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS); 472 } 473 474 if (!found) 475 dccp_pr_debug("%s(%d, ...) never requested\n", 476 dccp_feat_typename(type), feature); 477 return 0; 478} 479 480EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv); 481 482void dccp_feat_clean(struct dccp_minisock *dmsk) 483{ 484 struct dccp_opt_pend *opt, *next; 485 486 list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending, 487 dccpop_node) { 488 BUG_ON(opt->dccpop_val == NULL); 489 kfree(opt->dccpop_val); 490 491 if (opt->dccpop_sc != NULL) { 492 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL); 493 kfree(opt->dccpop_sc->dccpoc_val); 494 kfree(opt->dccpop_sc); 495 } 496 497 kfree(opt); 498 } 499 INIT_LIST_HEAD(&dmsk->dccpms_pending); 500 501 list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) { 502 BUG_ON(opt == NULL); 503 if (opt->dccpop_val != NULL) 504 kfree(opt->dccpop_val); 505 kfree(opt); 506 } 507 INIT_LIST_HEAD(&dmsk->dccpms_conf); 508} 509 510EXPORT_SYMBOL_GPL(dccp_feat_clean); 511 512/* this is to be called only when a listening sock creates its child. It is 513 * assumed by the function---the confirm is not duplicated, but rather it is 514 * "passed on". 515 */ 516int dccp_feat_clone(struct sock *oldsk, struct sock *newsk) 517{ 518 struct dccp_minisock *olddmsk = dccp_msk(oldsk); 519 struct dccp_minisock *newdmsk = dccp_msk(newsk); 520 struct dccp_opt_pend *opt; 521 int rc = 0; 522 523 INIT_LIST_HEAD(&newdmsk->dccpms_pending); 524 INIT_LIST_HEAD(&newdmsk->dccpms_conf); 525 526 list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) { 527 struct dccp_opt_pend *newopt; 528 /* copy the value of the option */ 529 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC); 530 531 if (val == NULL) 532 goto out_clean; 533 534 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC); 535 if (newopt == NULL) { 536 kfree(val); 537 goto out_clean; 538 } 539 540 /* insert the option */ 541 newopt->dccpop_val = val; 542 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending); 543 544 /* XXX what happens with backlogs and multiple connections at 545 * once... 546 */ 547 /* the master socket no longer needs to worry about confirms */ 548 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */ 549 550 /* reset state for a new socket */ 551 opt->dccpop_conf = 0; 552 } 553 554 /* XXX not doing anything about the conf queue */ 555 556out: 557 return rc; 558 559out_clean: 560 dccp_feat_clean(newdmsk); 561 rc = -ENOMEM; 562 goto out; 563} 564 565EXPORT_SYMBOL_GPL(dccp_feat_clone); 566 567static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat, 568 u8 *val, u8 len) 569{ 570 int rc = -ENOMEM; 571 u8 *copy = kmemdup(val, len, GFP_KERNEL); 572 573 if (copy != NULL) { 574 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL); 575 if (rc) 576 kfree(copy); 577 } 578 return rc; 579} 580 581int dccp_feat_init(struct dccp_minisock *dmsk) 582{ 583 int rc; 584 585 INIT_LIST_HEAD(&dmsk->dccpms_pending); 586 INIT_LIST_HEAD(&dmsk->dccpms_conf); 587 588 /* CCID L */ 589 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID, 590 &dmsk->dccpms_tx_ccid, 1); 591 if (rc) 592 goto out; 593 594 /* CCID R */ 595 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID, 596 &dmsk->dccpms_rx_ccid, 1); 597 if (rc) 598 goto out; 599 600 /* Ack ratio */ 601 rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO, 602 &dmsk->dccpms_ack_ratio, 1); 603out: 604 return rc; 605} 606 607EXPORT_SYMBOL_GPL(dccp_feat_init); 608 609#ifdef CONFIG_IP_DCCP_DEBUG 610const char *dccp_feat_typename(const u8 type) 611{ 612 switch(type) { 613 case DCCPO_CHANGE_L: return("ChangeL"); 614 case DCCPO_CONFIRM_L: return("ConfirmL"); 615 case DCCPO_CHANGE_R: return("ChangeR"); 616 case DCCPO_CONFIRM_R: return("ConfirmR"); 617 /* the following case must not appear in feature negotation */ 618 default: dccp_pr_debug("unknown type %d [BUG!]\n", type); 619 } 620 return NULL; 621} 622 623EXPORT_SYMBOL_GPL(dccp_feat_typename); 624 625const char *dccp_feat_name(const u8 feat) 626{ 627 static const char *feature_names[] = { 628 [DCCPF_RESERVED] = "Reserved", 629 [DCCPF_CCID] = "CCID", 630 [DCCPF_SHORT_SEQNOS] = "Allow Short Seqnos", 631 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window", 632 [DCCPF_ECN_INCAPABLE] = "ECN Incapable", 633 [DCCPF_ACK_RATIO] = "Ack Ratio", 634 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector", 635 [DCCPF_SEND_NDP_COUNT] = "Send NDP Count", 636 [DCCPF_MIN_CSUM_COVER] = "Min. Csum Coverage", 637 [DCCPF_DATA_CHECKSUM] = "Send Data Checksum", 638 }; 639 if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC) 640 return feature_names[DCCPF_RESERVED]; 641 642 if (feat >= DCCPF_MIN_CCID_SPECIFIC) 643 return "CCID-specific"; 644 645 return feature_names[feat]; 646} 647 648EXPORT_SYMBOL_GPL(dccp_feat_name); 649#endif /* CONFIG_IP_DCCP_DEBUG */ 650