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   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
  26 static const struct {
  27         u8                      feat_num;               /* DCCPF_xxx */
  28         enum dccp_feat_type     rxtx;                   /* RX or TX  */
  29         enum dccp_feat_type     reconciliation;         /* SP or NN  */
  30         u8                      default_value;          /* as in 6.4 */
  31 /*
  32  *    Lookup table for location and type of features (from RFC 4340/4342)
  33  *  +--------------------------+----+-----+----+----+---------+-----------+
  34  *  | Feature                  | Location | Reconc. | Initial |  Section  |
  35  *  |                          | RX | TX  | SP | NN |  Value  | Reference |
  36  *  +--------------------------+----+-----+----+----+---------+-----------+
  37  *  | DCCPF_CCID               |    |  X  | X  |    |   2     | 10        |
  38  *  | DCCPF_SHORT_SEQNOS       |    |  X  | X  |    |   0     |  7.6.1    |
  39  *  | DCCPF_SEQUENCE_WINDOW    |    |  X  |    | X  | 100     |  7.5.2    |
  40  *  | DCCPF_ECN_INCAPABLE      | X  |     | X  |    |   0     | 12.1      |
  41  *  | DCCPF_ACK_RATIO          |    |  X  |    | X  |   2     | 11.3      |
  42  *  | DCCPF_SEND_ACK_VECTOR    | X  |     | X  |    |   0     | 11.5      |
  43  *  | DCCPF_SEND_NDP_COUNT     |    |  X  | X  |    |   0     |  7.7.2    |
  44  *  | DCCPF_MIN_CSUM_COVER     | X  |     | X  |    |   0     |  9.2.1    |
  45  *  | DCCPF_DATA_CHECKSUM      | X  |     | X  |    |   0     |  9.3.1    |
  46  *  | DCCPF_SEND_LEV_RATE      | X  |     | X  |    |   0     | 4342/8.4  |
  47  *  +--------------------------+----+-----+----+----+---------+-----------+
  48  */
  49 } dccp_feat_table[] = {
  50         { DCCPF_CCID,            FEAT_AT_TX, FEAT_SP, 2 },
  51         { DCCPF_SHORT_SEQNOS,    FEAT_AT_TX, FEAT_SP, 0 },
  52         { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
  53         { DCCPF_ECN_INCAPABLE,   FEAT_AT_RX, FEAT_SP, 0 },
  54         { DCCPF_ACK_RATIO,       FEAT_AT_TX, FEAT_NN, 2 },
  55         { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
  56         { DCCPF_SEND_NDP_COUNT,  FEAT_AT_TX, FEAT_SP, 0 },
  57         { DCCPF_MIN_CSUM_COVER,  FEAT_AT_RX, FEAT_SP, 0 },
  58         { DCCPF_DATA_CHECKSUM,   FEAT_AT_RX, FEAT_SP, 0 },
  59         { DCCPF_SEND_LEV_RATE,   FEAT_AT_RX, FEAT_SP, 0 },
  60 };
  61 #define DCCP_FEAT_SUPPORTED_MAX         ARRAY_SIZE(dccp_feat_table)
  62
  63 /**
  64  * dccp_feat_index  -  Hash function to map feature number into array position
  65  * Returns consecutive array index or -1 if the feature is not understood.
  66  */
  67 static int dccp_feat_index(u8 feat_num)
  68 {
  69         /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
  70         if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)
  71                 return feat_num - 1;
  72
  73         /*
  74          * Other features: add cases for new feature types here after adding
  75          * them to the above table.
  76          */
  77         switch (feat_num) {
  78         case DCCPF_SEND_LEV_RATE:
  79                         return DCCP_FEAT_SUPPORTED_MAX - 1;
  80         }
  81         return -1;
  82 }
  83
  84 static u8 dccp_feat_type(u8 feat_num)
  85 {
  86         int idx = dccp_feat_index(feat_num);
  87
  88         if (idx < 0)
  89                 return FEAT_UNKNOWN;
  90         return dccp_feat_table[idx].reconciliation;
  91 }
  92
  93 static int dccp_feat_default_value(u8 feat_num)
  94 {
  95         int idx = dccp_feat_index(feat_num);
  96
  97         return idx < 0 ? : dccp_feat_table[idx].default_value;
  98 }
  99
 100 /* copy constructor, fval must not already contain allocated memory */
 101 static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
 102 {
 103         fval->sp.len = len;
 104         if (fval->sp.len > 0) {
 105                 fval->sp.vec = kmemdup(val, len, gfp_any());
 106                 if (fval->sp.vec == NULL) {
 107                         fval->sp.len = 0;
 108                         return -ENOBUFS;
 109                 }
 110         }
 111         return 0;
 112 }
 113
 114 static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
 115 {
 116         if (unlikely(val == NULL))
 117                 return;
 118         if (dccp_feat_type(feat_num) == FEAT_SP)
 119                 kfree(val->sp.vec);
 120         memset(val, 0, sizeof(*val));
 121 }
 122
 123 static struct dccp_feat_entry *
 124               dccp_feat_clone_entry(struct dccp_feat_entry const *original)
 125 {
 126         struct dccp_feat_entry *new;
 127         u8 type = dccp_feat_type(original->feat_num);
 128
 129         if (type == FEAT_UNKNOWN)
 130                 return NULL;
 131
 132         new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any());
 133         if (new == NULL)
 134                 return NULL;
 135
 136         if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val,
 137                                                       original->val.sp.vec,
 138                                                       original->val.sp.len)) {
 139                 kfree(new);
 140                 return NULL;
 141         }
 142         return new;
 143 }
 144
 145 static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
 146 {
 147         if (entry != NULL) {
 148                 dccp_feat_val_destructor(entry->feat_num, &entry->val);
 149                 kfree(entry);
 150         }
 151 }
 152
 153 /*
 154  * List management functions
 155  *
 156  * Feature negotiation lists rely on and maintain the following invariants:
 157  * - each feat_num in the list is known, i.e. we know its type and default value
 158  * - each feat_num/is_local combination is unique (old entries are overwritten)
 159  * - SP values are always freshly allocated
 160  * - list is sorted in increasing order of feature number (faster lookup)
 161  */
 162 static struct dccp_feat_entry *dccp_feat_list_lookup(struct list_head *fn_list,
 163                                                      u8 feat_num, bool is_local)
 164 {
 165         struct dccp_feat_entry *entry;
 166
 167         list_for_each_entry(entry, fn_list, node)
 168                 if (entry->feat_num == feat_num && entry->is_local == is_local)
 169                         return entry;
 170                 else if (entry->feat_num > feat_num)
 171                         break;
 172         return NULL;
 173 }
 174
 175 /**
 176  * dccp_feat_entry_new  -  Central list update routine (called by all others)
 177  * @head:  list to add to
 178  * @feat:  feature number
 179  * @local: whether the local (1) or remote feature with number @feat is meant
 180  * This is the only constructor and serves to ensure the above invariants.
 181  */
 182 static struct dccp_feat_entry *
 183               dccp_feat_entry_new(struct list_head *head, u8 feat, bool local)
 184 {
 185         struct dccp_feat_entry *entry;
 186
 187         list_for_each_entry(entry, head, node)
 188                 if (entry->feat_num == feat && entry->is_local == local) {
 189                         dccp_feat_val_destructor(entry->feat_num, &entry->val);
 190                         return entry;
 191                 } else if (entry->feat_num > feat) {
 192                         head = &entry->node;
 193                         break;
 194                 }
 195
 196         entry = kmalloc(sizeof(*entry), gfp_any());
 197         if (entry != NULL) {
 198                 entry->feat_num = feat;
 199                 entry->is_local = local;
 200                 list_add_tail(&entry->node, head);
 201         }
 202         return entry;
 203 }
 204
 205 /**
 206  * dccp_feat_push_change  -  Add/overwrite a Change option in the list
 207  * @fn_list: feature-negotiation list to update
 208  * @feat: one of %dccp_feature_numbers
 209  * @local: whether local (1) or remote (0) @feat_num is meant
 210  * @needs_mandatory: whether to use Mandatory feature negotiation options
 211  * @fval: pointer to NN/SP value to be inserted (will be copied)
 212  */
 213 static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
 214                                  u8 mandatory, dccp_feat_val *fval)
 215 {
 216         struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
 217
 218         if (new == NULL)
 219                 return -ENOMEM;
 220
 221         new->feat_num        = feat;
 222         new->is_local        = local;
 223         new->state           = FEAT_INITIALISING;
 224         new->needs_confirm   = 0;
 225         new->empty_confirm   = 0;
 226         new->val             = *fval;
 227         new->needs_mandatory = mandatory;
 228
 229         return 0;
 230 }
 231
 232 /**
 233  * dccp_feat_push_confirm  -  Add a Confirm entry to the FN list
 234  * @fn_list: feature-negotiation list to add to
 235  * @feat: one of %dccp_feature_numbers
 236  * @local: whether local (1) or remote (0) @feat_num is being confirmed
 237  * @fval: pointer to NN/SP value to be inserted or NULL
 238  * Returns 0 on success, a Reset code for further processing otherwise.
 239  */
 240 static int dccp_feat_push_confirm(struct list_head *fn_list, u8 feat, u8 local,
 241                                   dccp_feat_val *fval)
 242 {
 243         struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
 244
 245         if (new == NULL)
 246                 return DCCP_RESET_CODE_TOO_BUSY;
 247
 248         new->feat_num        = feat;
 249         new->is_local        = local;
 250         new->state           = FEAT_STABLE;     /* transition in 6.6.2 */
 251         new->needs_confirm   = 1;
 252         new->empty_confirm   = (fval == NULL);
 253         new->val.nn          = 0;               /* zeroes the whole structure */
 254         if (!new->empty_confirm)
 255                 new->val     = *fval;
 256         new->needs_mandatory = 0;
 257
 258         return 0;
 259 }
 260
 261 static int dccp_push_empty_confirm(struct list_head *fn_list, u8 feat, u8 local)
 262 {
 263         return dccp_feat_push_confirm(fn_list, feat, local, NULL);
 264 }
 265
 266 static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
 267 {
 268         list_del(&entry->node);
 269         dccp_feat_entry_destructor(entry);
 270 }
 271
 272 void dccp_feat_list_purge(struct list_head *fn_list)
 273 {
 274         struct dccp_feat_entry *entry, *next;
 275
 276         list_for_each_entry_safe(entry, next, fn_list, node)
 277                 dccp_feat_entry_destructor(entry);
 278         INIT_LIST_HEAD(fn_list);
 279 }
 280 EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
 281
 282 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
 283                      u8 *val, u8 len, gfp_t gfp)
 284 {
 285         struct dccp_opt_pend *opt;
 286
 287         dccp_feat_debug(type, feature, *val);
 288
 289         if (len > 3) {
 290                 DCCP_WARN("invalid length %d\n", len);
 291                 return -EINVAL;
 292         }
 293         /* XXX add further sanity checks */
 294
 295         /* check if that feature is already being negotiated */
 296         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 297                 /* ok we found a negotiation for this option already */
 298                 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
 299                         dccp_pr_debug("Replacing old\n");
 300                         /* replace */
 301                         BUG_ON(opt->dccpop_val == NULL);
 302                         kfree(opt->dccpop_val);
 303                         opt->dccpop_val  = val;
 304                         opt->dccpop_len  = len;
 305                         opt->dccpop_conf = 0;
 306                         return 0;
 307                 }
 308         }
 309
 310         /* negotiation for a new feature */
 311         opt = kmalloc(sizeof(*opt), gfp);
 312         if (opt == NULL)
 313                 return -ENOMEM;
 314
 315         opt->dccpop_type = type;
 316         opt->dccpop_feat = feature;
 317         opt->dccpop_len  = len;
 318         opt->dccpop_val  = val;
 319         opt->dccpop_conf = 0;
 320         opt->dccpop_sc   = NULL;
 321
 322         BUG_ON(opt->dccpop_val == NULL);
 323
 324         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
 325         return 0;
 326 }
 327
 328 EXPORT_SYMBOL_GPL(dccp_feat_change);
 329
 330 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
 331 {
 332         struct dccp_sock *dp = dccp_sk(sk);
 333         struct dccp_minisock *dmsk = dccp_msk(sk);
 334         /* figure out if we are changing our CCID or the peer's */
 335         const int rx = type == DCCPO_CHANGE_R;
 336         const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
 337         struct ccid *new_ccid;
 338
 339         /* Check if nothing is being changed. */
 340         if (ccid_nr == new_ccid_nr)
 341                 return 0;
 342
 343         new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
 344         if (new_ccid == NULL)
 345                 return -ENOMEM;
 346
 347         if (rx) {
 348                 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
 349                 dp->dccps_hc_rx_ccid = new_ccid;
 350                 dmsk->dccpms_rx_ccid = new_ccid_nr;
 351         } else {
 352                 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 353                 dp->dccps_hc_tx_ccid = new_ccid;
 354                 dmsk->dccpms_tx_ccid = new_ccid_nr;
 355         }
 356
 357         return 0;
 358 }
 359
 360 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
 361 {
 362         dccp_feat_debug(type, feat, val);
 363
 364         switch (feat) {
 365         case DCCPF_CCID:
 366                 return dccp_feat_update_ccid(sk, type, val);
 367         default:
 368                 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
 369                               dccp_feat_typename(type), feat);
 370                 break;
 371         }
 372         return 0;
 373 }
 374
 375 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
 376                                u8 *rpref, u8 rlen)
 377 {
 378         struct dccp_sock *dp = dccp_sk(sk);
 379         u8 *spref, slen, *res = NULL;
 380         int i, j, rc, agree = 1;
 381
 382         BUG_ON(rpref == NULL);
 383
 384         /* check if we are the black sheep */
 385         if (dp->dccps_role == DCCP_ROLE_CLIENT) {
 386                 spref = rpref;
 387                 slen  = rlen;
 388                 rpref = opt->dccpop_val;
 389                 rlen  = opt->dccpop_len;
 390         } else {
 391                 spref = opt->dccpop_val;
 392                 slen  = opt->dccpop_len;
 393         }
 394         /*
 395          * Now we have server preference list in spref and client preference in
 396          * rpref
 397          */
 398         BUG_ON(spref == NULL);
 399         BUG_ON(rpref == NULL);
 400
 401         /* FIXME sanity check vals */
 402
 403         /* Are values in any order?  XXX Lame "algorithm" here */
 404         for (i = 0; i < slen; i++) {
 405                 for (j = 0; j < rlen; j++) {
 406                         if (spref[i] == rpref[j]) {
 407                                 res = &spref[i];
 408                                 break;
 409                         }
 410                 }
 411                 if (res)
 412                         break;
 413         }
 414
 415         /* we didn't agree on anything */
 416         if (res == NULL) {
 417                 /* confirm previous value */
 418                 switch (opt->dccpop_feat) {
 419                 case DCCPF_CCID:
 420                         /* XXX did i get this right? =P */
 421                         if (opt->dccpop_type == DCCPO_CHANGE_L)
 422                                 res = &dccp_msk(sk)->dccpms_tx_ccid;
 423                         else
 424                                 res = &dccp_msk(sk)->dccpms_rx_ccid;
 425                         break;
 426
 427                 default:
 428                         DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
 429                         /* XXX implement res */
 430                         return -EFAULT;
 431                 }
 432
 433                 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
 434                 agree = 0; /* this is used for mandatory options... */
 435         }
 436
 437         /* need to put result and our preference list */
 438         rlen = 1 + opt->dccpop_len;
 439         rpref = kmalloc(rlen, GFP_ATOMIC);
 440         if (rpref == NULL)
 441                 return -ENOMEM;
 442
 443         *rpref = *res;
 444         memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
 445
 446         /* put it in the "confirm queue" */
 447         if (opt->dccpop_sc == NULL) {
 448                 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
 449                 if (opt->dccpop_sc == NULL) {
 450                         kfree(rpref);
 451                         return -ENOMEM;
 452                 }
 453         } else {
 454                 /* recycle the confirm slot */
 455                 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 456                 kfree(opt->dccpop_sc->dccpoc_val);
 457                 dccp_pr_debug("recycling confirm slot\n");
 458         }
 459         memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
 460
 461         opt->dccpop_sc->dccpoc_val = rpref;
 462         opt->dccpop_sc->dccpoc_len = rlen;
 463
 464         /* update the option on our side [we are about to send the confirm] */
 465         rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
 466         if (rc) {
 467                 kfree(opt->dccpop_sc->dccpoc_val);
 468                 kfree(opt->dccpop_sc);
 469                 opt->dccpop_sc = NULL;
 470                 return rc;
 471         }
 472
 473         dccp_pr_debug("Will confirm %d\n", *rpref);
 474
 475         /* say we want to change to X but we just got a confirm X, suppress our
 476          * change
 477          */
 478         if (!opt->dccpop_conf) {
 479                 if (*opt->dccpop_val == *res)
 480                         opt->dccpop_conf = 1;
 481                 dccp_pr_debug("won't ask for change of same feature\n");
 482         }
 483
 484         return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
 485 }
 486
 487 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 488 {
 489         struct dccp_minisock *dmsk = dccp_msk(sk);
 490         struct dccp_opt_pend *opt;
 491         int rc = 1;
 492         u8 t;
 493
 494         /*
 495          * We received a CHANGE.  We gotta match it against our own preference
 496          * list.  If we got a CHANGE_R it means it's a change for us, so we need
 497          * to compare our CHANGE_L list.
 498          */
 499         if (type == DCCPO_CHANGE_L)
 500                 t = DCCPO_CHANGE_R;
 501         else
 502                 t = DCCPO_CHANGE_L;
 503
 504         /* find our preference list for this feature */
 505         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 506                 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
 507                         continue;
 508
 509                 /* find the winner from the two preference lists */
 510                 rc = dccp_feat_reconcile(sk, opt, val, len);
 511                 break;
 512         }
 513
 514         /* We didn't deal with the change.  This can happen if we have no
 515          * preference list for the feature.  In fact, it just shouldn't
 516          * happen---if we understand a feature, we should have a preference list
 517          * with at least the default value.
 518          */
 519         BUG_ON(rc == 1);
 520
 521         return rc;
 522 }
 523
 524 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 525 {
 526         struct dccp_opt_pend *opt;
 527         struct dccp_minisock *dmsk = dccp_msk(sk);
 528         u8 *copy;
 529         int rc;
 530
 531         /* NN features must be Change L (sec. 6.3.2) */
 532         if (type != DCCPO_CHANGE_L) {
 533                 dccp_pr_debug("received %s for NN feature %d\n",
 534                                 dccp_feat_typename(type), feature);
 535                 return -EFAULT;
 536         }
 537
 538         /* XXX sanity check opt val */
 539
 540         /* copy option so we can confirm it */
 541         opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 542         if (opt == NULL)
 543                 return -ENOMEM;
 544
 545         copy = kmemdup(val, len, GFP_ATOMIC);
 546         if (copy == NULL) {
 547                 kfree(opt);
 548                 return -ENOMEM;
 549         }
 550
 551         opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
 552         opt->dccpop_feat = feature;
 553         opt->dccpop_val  = copy;
 554         opt->dccpop_len  = len;
 555
 556         /* change feature */
 557         rc = dccp_feat_update(sk, type, feature, *val);
 558         if (rc) {
 559                 kfree(opt->dccpop_val);
 560                 kfree(opt);
 561                 return rc;
 562         }
 563
 564         dccp_feat_debug(type, feature, *copy);
 565
 566         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 567
 568         return 0;
 569 }
 570
 571 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
 572                                     u8 type, u8 feature)
 573 {
 574         /* XXX check if other confirms for that are queued and recycle slot */
 575         struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 576
 577         if (opt == NULL) {
 578                 /* XXX what do we do?  Ignoring should be fine.  It's a change
 579                  * after all =P
 580                  */
 581                 return;
 582         }
 583
 584         switch (type) {
 585         case DCCPO_CHANGE_L:
 586                 opt->dccpop_type = DCCPO_CONFIRM_R;
 587                 break;
 588         case DCCPO_CHANGE_R:
 589                 opt->dccpop_type = DCCPO_CONFIRM_L;
 590                 break;
 591         default:
 592                 DCCP_WARN("invalid type %d\n", type);
 593                 kfree(opt);
 594                 return;
 595         }
 596         opt->dccpop_feat = feature;
 597         opt->dccpop_val  = NULL;
 598         opt->dccpop_len  = 0;
 599
 600         /* change feature */
 601         dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
 602
 603         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 604 }
 605
 606 static void dccp_feat_flush_confirm(struct sock *sk)
 607 {
 608         struct dccp_minisock *dmsk = dccp_msk(sk);
 609         /* Check if there is anything to confirm in the first place */
 610         int yes = !list_empty(&dmsk->dccpms_conf);
 611
 612         if (!yes) {
 613                 struct dccp_opt_pend *opt;
 614
 615                 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 616                         if (opt->dccpop_conf) {
 617                                 yes = 1;
 618                                 break;
 619                         }
 620                 }
 621         }
 622
 623         if (!yes)
 624                 return;
 625
 626         /* OK there is something to confirm... */
 627         /* XXX check if packet is in flight?  Send delayed ack?? */
 628         if (sk->sk_state == DCCP_OPEN)
 629                 dccp_send_ack(sk);
 630 }
 631
 632 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 633 {
 634         int rc;
 635
 636         dccp_feat_debug(type, feature, *val);
 637
 638         /* figure out if it's SP or NN feature */
 639         switch (feature) {
 640         /* deal with SP features */
 641         case DCCPF_CCID:
 642                 rc = dccp_feat_sp(sk, type, feature, val, len);
 643                 break;
 644
 645         /* deal with NN features */
 646         case DCCPF_ACK_RATIO:
 647                 rc = dccp_feat_nn(sk, type, feature, val, len);
 648                 break;
 649
 650         /* XXX implement other features */
 651         default:
 652                 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
 653                               dccp_feat_typename(type), feature);
 654                 rc = -EFAULT;
 655                 break;
 656         }
 657
 658         /* check if there were problems changing features */
 659         if (rc) {
 660                 /* If we don't agree on SP, we sent a confirm for old value.
 661                  * However we propagate rc to caller in case option was
 662                  * mandatory
 663                  */
 664                 if (rc != DCCP_FEAT_SP_NOAGREE)
 665                         dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
 666         }
 667
 668         /* generate the confirm [if required] */
 669         dccp_feat_flush_confirm(sk);
 670
 671         return rc;
 672 }
 673
 674 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
 675
 676 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
 677                            u8 *val, u8 len)
 678 {
 679         u8 t;
 680         struct dccp_opt_pend *opt;
 681         struct dccp_minisock *dmsk = dccp_msk(sk);
 682         int found = 0;
 683         int all_confirmed = 1;
 684
 685         dccp_feat_debug(type, feature, *val);
 686
 687         /* locate our change request */
 688         switch (type) {
 689         case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
 690         case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
 691         default:              DCCP_WARN("invalid type %d\n", type);
 692                               return 1;
 693
 694         }
 695         /* XXX sanity check feature value */
 696
 697         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 698                 if (!opt->dccpop_conf && opt->dccpop_type == t &&
 699                     opt->dccpop_feat == feature) {
 700                         found = 1;
 701                         dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
 702
 703                         /* XXX do sanity check */
 704
 705                         opt->dccpop_conf = 1;
 706
 707                         /* We got a confirmation---change the option */
 708                         dccp_feat_update(sk, opt->dccpop_type,
 709                                          opt->dccpop_feat, *val);
 710
 711                         /* XXX check the return value of dccp_feat_update */
 712                         break;
 713                 }
 714
 715                 if (!opt->dccpop_conf)
 716                         all_confirmed = 0;
 717         }
 718
 719         /* fix re-transmit timer */
 720         /* XXX gotta make sure that no option negotiation occurs during
 721          * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
 722          * on.  if all options are confirmed it might kill timer which should
 723          * remain alive until close is received.
 724          */
 725         if (all_confirmed) {
 726                 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
 727                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
 728         }
 729
 730         if (!found)
 731                 dccp_pr_debug("%s(%d, ...) never requested\n",
 732                               dccp_feat_typename(type), feature);
 733         return 0;
 734 }
 735
 736 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
 737
 738 void dccp_feat_clean(struct dccp_minisock *dmsk)
 739 {
 740         struct dccp_opt_pend *opt, *next;
 741
 742         list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
 743                                  dccpop_node) {
 744                 BUG_ON(opt->dccpop_val == NULL);
 745                 kfree(opt->dccpop_val);
 746
 747                 if (opt->dccpop_sc != NULL) {
 748                         BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 749                         kfree(opt->dccpop_sc->dccpoc_val);
 750                         kfree(opt->dccpop_sc);
 751                 }
 752
 753                 kfree(opt);
 754         }
 755         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 756
 757         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
 758                 BUG_ON(opt == NULL);
 759                 if (opt->dccpop_val != NULL)
 760                         kfree(opt->dccpop_val);
 761                 kfree(opt);
 762         }
 763         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 764 }
 765
 766 EXPORT_SYMBOL_GPL(dccp_feat_clean);
 767
 768 /* this is to be called only when a listening sock creates its child.  It is
 769  * assumed by the function---the confirm is not duplicated, but rather it is
 770  * "passed on".
 771  */
 772 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
 773 {
 774         struct dccp_minisock *olddmsk = dccp_msk(oldsk);
 775         struct dccp_minisock *newdmsk = dccp_msk(newsk);
 776         struct dccp_opt_pend *opt;
 777         int rc = 0;
 778
 779         INIT_LIST_HEAD(&newdmsk->dccpms_pending);
 780         INIT_LIST_HEAD(&newdmsk->dccpms_conf);
 781
 782         list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
 783                 struct dccp_opt_pend *newopt;
 784                 /* copy the value of the option */
 785                 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
 786
 787                 if (val == NULL)
 788                         goto out_clean;
 789
 790                 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
 791                 if (newopt == NULL) {
 792                         kfree(val);
 793                         goto out_clean;
 794                 }
 795
 796                 /* insert the option */
 797                 newopt->dccpop_val = val;
 798                 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
 799
 800                 /* XXX what happens with backlogs and multiple connections at
 801                  * once...
 802                  */
 803                 /* the master socket no longer needs to worry about confirms */
 804                 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
 805
 806                 /* reset state for a new socket */
 807                 opt->dccpop_conf = 0;
 808         }
 809
 810         /* XXX not doing anything about the conf queue */
 811
 812 out:
 813         return rc;
 814
 815 out_clean:
 816         dccp_feat_clean(newdmsk);
 817         rc = -ENOMEM;
 818         goto out;
 819 }
 820
 821 EXPORT_SYMBOL_GPL(dccp_feat_clone);
 822
 823 static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
 824                             u8 *val, u8 len)
 825 {
 826         int rc = -ENOMEM;
 827         u8 *copy = kmemdup(val, len, GFP_KERNEL);
 828
 829         if (copy != NULL) {
 830                 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
 831                 if (rc)
 832                         kfree(copy);
 833         }
 834         return rc;
 835 }
 836
 837 int dccp_feat_init(struct dccp_minisock *dmsk)
 838 {
 839         int rc;
 840
 841         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 842         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 843
 844         /* CCID L */
 845         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
 846                               &dmsk->dccpms_tx_ccid, 1);
 847         if (rc)
 848                 goto out;
 849
 850         /* CCID R */
 851         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
 852                               &dmsk->dccpms_rx_ccid, 1);
 853         if (rc)
 854                 goto out;
 855
 856         /* Ack ratio */
 857         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
 858                               &dmsk->dccpms_ack_ratio, 1);
 859 out:
 860         return rc;
 861 }
 862
 863 EXPORT_SYMBOL_GPL(dccp_feat_init);
 864
 865 #ifdef CONFIG_IP_DCCP_DEBUG
 866 const char *dccp_feat_typename(const u8 type)
 867 {
 868         switch(type) {
 869         case DCCPO_CHANGE_L:  return("ChangeL");
 870         case DCCPO_CONFIRM_L: return("ConfirmL");
 871         case DCCPO_CHANGE_R:  return("ChangeR");
 872         case DCCPO_CONFIRM_R: return("ConfirmR");
 873         /* the following case must not appear in feature negotation  */
 874         default:              dccp_pr_debug("unknown type %d [BUG!]\n", type);
 875         }
 876         return NULL;
 877 }
 878
 879 EXPORT_SYMBOL_GPL(dccp_feat_typename);
 880
 881 const char *dccp_feat_name(const u8 feat)
 882 {
 883         static const char *feature_names[] = {
 884                 [DCCPF_RESERVED]        = "Reserved",
 885                 [DCCPF_CCID]            = "CCID",
 886                 [DCCPF_SHORT_SEQNOS]    = "Allow Short Seqnos",
 887                 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
 888                 [DCCPF_ECN_INCAPABLE]   = "ECN Incapable",
 889                 [DCCPF_ACK_RATIO]       = "Ack Ratio",
 890                 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
 891                 [DCCPF_SEND_NDP_COUNT]  = "Send NDP Count",
 892                 [DCCPF_MIN_CSUM_COVER]  = "Min. Csum Coverage",
 893                 [DCCPF_DATA_CHECKSUM]   = "Send Data Checksum",
 894         };
 895         if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
 896                 return feature_names[DCCPF_RESERVED];
 897
 898         if (feat ==  DCCPF_SEND_LEV_RATE)
 899                 return "Send Loss Event Rate";
 900         if (feat >= DCCPF_MIN_CCID_SPECIFIC)
 901                 return "CCID-specific";
 902
 903         return feature_names[feat];
 904 }
 905
 906 EXPORT_SYMBOL_GPL(dccp_feat_name);
 907 #endif /* CONFIG_IP_DCCP_DEBUG */