net/dccp/feat.c

   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 /* generate @to as full clone of @from - @to must not contain any nodes */
 283 int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
 284 {
 285         struct dccp_feat_entry *entry, *new;
 286
 287         INIT_LIST_HEAD(to);
 288         list_for_each_entry(entry, from, node) {
 289                 new = dccp_feat_clone_entry(entry);
 290                 if (new == NULL)
 291                         goto cloning_failed;
 292                 list_add_tail(&new->node, to);
 293         }
 294         return 0;
 295
 296 cloning_failed:
 297         dccp_feat_list_purge(to);
 298         return -ENOMEM;
 299 }
 300
 301 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
 302                      u8 *val, u8 len, gfp_t gfp)
 303 {
 304         struct dccp_opt_pend *opt;
 305
 306         dccp_feat_debug(type, feature, *val);
 307
 308         if (len > 3) {
 309                 DCCP_WARN("invalid length %d\n", len);
 310                 return -EINVAL;
 311         }
 312         /* XXX add further sanity checks */
 313
 314         /* check if that feature is already being negotiated */
 315         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 316                 /* ok we found a negotiation for this option already */
 317                 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
 318                         dccp_pr_debug("Replacing old\n");
 319                         /* replace */
 320                         BUG_ON(opt->dccpop_val == NULL);
 321                         kfree(opt->dccpop_val);
 322                         opt->dccpop_val  = val;
 323                         opt->dccpop_len  = len;
 324                         opt->dccpop_conf = 0;
 325                         return 0;
 326                 }
 327         }
 328
 329         /* negotiation for a new feature */
 330         opt = kmalloc(sizeof(*opt), gfp);
 331         if (opt == NULL)
 332                 return -ENOMEM;
 333
 334         opt->dccpop_type = type;
 335         opt->dccpop_feat = feature;
 336         opt->dccpop_len  = len;
 337         opt->dccpop_val  = val;
 338         opt->dccpop_conf = 0;
 339         opt->dccpop_sc   = NULL;
 340
 341         BUG_ON(opt->dccpop_val == NULL);
 342
 343         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
 344         return 0;
 345 }
 346
 347 EXPORT_SYMBOL_GPL(dccp_feat_change);
 348
 349 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
 350 {
 351         struct dccp_sock *dp = dccp_sk(sk);
 352         struct dccp_minisock *dmsk = dccp_msk(sk);
 353         /* figure out if we are changing our CCID or the peer's */
 354         const int rx = type == DCCPO_CHANGE_R;
 355         const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
 356         struct ccid *new_ccid;
 357
 358         /* Check if nothing is being changed. */
 359         if (ccid_nr == new_ccid_nr)
 360                 return 0;
 361
 362         new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
 363         if (new_ccid == NULL)
 364                 return -ENOMEM;
 365
 366         if (rx) {
 367                 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
 368                 dp->dccps_hc_rx_ccid = new_ccid;
 369                 dmsk->dccpms_rx_ccid = new_ccid_nr;
 370         } else {
 371                 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 372                 dp->dccps_hc_tx_ccid = new_ccid;
 373                 dmsk->dccpms_tx_ccid = new_ccid_nr;
 374         }
 375
 376         return 0;
 377 }
 378
 379 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
 380 {
 381         dccp_feat_debug(type, feat, val);
 382
 383         switch (feat) {
 384         case DCCPF_CCID:
 385                 return dccp_feat_update_ccid(sk, type, val);
 386         default:
 387                 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
 388                               dccp_feat_typename(type), feat);
 389                 break;
 390         }
 391         return 0;
 392 }
 393
 394 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
 395                                u8 *rpref, u8 rlen)
 396 {
 397         struct dccp_sock *dp = dccp_sk(sk);
 398         u8 *spref, slen, *res = NULL;
 399         int i, j, rc, agree = 1;
 400
 401         BUG_ON(rpref == NULL);
 402
 403         /* check if we are the black sheep */
 404         if (dp->dccps_role == DCCP_ROLE_CLIENT) {
 405                 spref = rpref;
 406                 slen  = rlen;
 407                 rpref = opt->dccpop_val;
 408                 rlen  = opt->dccpop_len;
 409         } else {
 410                 spref = opt->dccpop_val;
 411                 slen  = opt->dccpop_len;
 412         }
 413         /*
 414          * Now we have server preference list in spref and client preference in
 415          * rpref
 416          */
 417         BUG_ON(spref == NULL);
 418         BUG_ON(rpref == NULL);
 419
 420         /* FIXME sanity check vals */
 421
 422         /* Are values in any order?  XXX Lame "algorithm" here */
 423         for (i = 0; i < slen; i++) {
 424                 for (j = 0; j < rlen; j++) {
 425                         if (spref[i] == rpref[j]) {
 426                                 res = &spref[i];
 427                                 break;
 428                         }
 429                 }
 430                 if (res)
 431                         break;
 432         }
 433
 434         /* we didn't agree on anything */
 435         if (res == NULL) {
 436                 /* confirm previous value */
 437                 switch (opt->dccpop_feat) {
 438                 case DCCPF_CCID:
 439                         /* XXX did i get this right? =P */
 440                         if (opt->dccpop_type == DCCPO_CHANGE_L)
 441                                 res = &dccp_msk(sk)->dccpms_tx_ccid;
 442                         else
 443                                 res = &dccp_msk(sk)->dccpms_rx_ccid;
 444                         break;
 445
 446                 default:
 447                         DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
 448                         /* XXX implement res */
 449                         return -EFAULT;
 450                 }
 451
 452                 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
 453                 agree = 0; /* this is used for mandatory options... */
 454         }
 455
 456         /* need to put result and our preference list */
 457         rlen = 1 + opt->dccpop_len;
 458         rpref = kmalloc(rlen, GFP_ATOMIC);
 459         if (rpref == NULL)
 460                 return -ENOMEM;
 461
 462         *rpref = *res;
 463         memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
 464
 465         /* put it in the "confirm queue" */
 466         if (opt->dccpop_sc == NULL) {
 467                 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
 468                 if (opt->dccpop_sc == NULL) {
 469                         kfree(rpref);
 470                         return -ENOMEM;
 471                 }
 472         } else {
 473                 /* recycle the confirm slot */
 474                 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 475                 kfree(opt->dccpop_sc->dccpoc_val);
 476                 dccp_pr_debug("recycling confirm slot\n");
 477         }
 478         memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
 479
 480         opt->dccpop_sc->dccpoc_val = rpref;
 481         opt->dccpop_sc->dccpoc_len = rlen;
 482
 483         /* update the option on our side [we are about to send the confirm] */
 484         rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
 485         if (rc) {
 486                 kfree(opt->dccpop_sc->dccpoc_val);
 487                 kfree(opt->dccpop_sc);
 488                 opt->dccpop_sc = NULL;
 489                 return rc;
 490         }
 491
 492         dccp_pr_debug("Will confirm %d\n", *rpref);
 493
 494         /* say we want to change to X but we just got a confirm X, suppress our
 495          * change
 496          */
 497         if (!opt->dccpop_conf) {
 498                 if (*opt->dccpop_val == *res)
 499                         opt->dccpop_conf = 1;
 500                 dccp_pr_debug("won't ask for change of same feature\n");
 501         }
 502
 503         return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
 504 }
 505
 506 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 507 {
 508         struct dccp_minisock *dmsk = dccp_msk(sk);
 509         struct dccp_opt_pend *opt;
 510         int rc = 1;
 511         u8 t;
 512
 513         /*
 514          * We received a CHANGE.  We gotta match it against our own preference
 515          * list.  If we got a CHANGE_R it means it's a change for us, so we need
 516          * to compare our CHANGE_L list.
 517          */
 518         if (type == DCCPO_CHANGE_L)
 519                 t = DCCPO_CHANGE_R;
 520         else
 521                 t = DCCPO_CHANGE_L;
 522
 523         /* find our preference list for this feature */
 524         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 525                 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
 526                         continue;
 527
 528                 /* find the winner from the two preference lists */
 529                 rc = dccp_feat_reconcile(sk, opt, val, len);
 530                 break;
 531         }
 532
 533         /* We didn't deal with the change.  This can happen if we have no
 534          * preference list for the feature.  In fact, it just shouldn't
 535          * happen---if we understand a feature, we should have a preference list
 536          * with at least the default value.
 537          */
 538         BUG_ON(rc == 1);
 539
 540         return rc;
 541 }
 542
 543 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 544 {
 545         struct dccp_opt_pend *opt;
 546         struct dccp_minisock *dmsk = dccp_msk(sk);
 547         u8 *copy;
 548         int rc;
 549
 550         /* NN features must be Change L (sec. 6.3.2) */
 551         if (type != DCCPO_CHANGE_L) {
 552                 dccp_pr_debug("received %s for NN feature %d\n",
 553                                 dccp_feat_typename(type), feature);
 554                 return -EFAULT;
 555         }
 556
 557         /* XXX sanity check opt val */
 558
 559         /* copy option so we can confirm it */
 560         opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 561         if (opt == NULL)
 562                 return -ENOMEM;
 563
 564         copy = kmemdup(val, len, GFP_ATOMIC);
 565         if (copy == NULL) {
 566                 kfree(opt);
 567                 return -ENOMEM;
 568         }
 569
 570         opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
 571         opt->dccpop_feat = feature;
 572         opt->dccpop_val  = copy;
 573         opt->dccpop_len  = len;
 574
 575         /* change feature */
 576         rc = dccp_feat_update(sk, type, feature, *val);
 577         if (rc) {
 578                 kfree(opt->dccpop_val);
 579                 kfree(opt);
 580                 return rc;
 581         }
 582
 583         dccp_feat_debug(type, feature, *copy);
 584
 585         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 586
 587         return 0;
 588 }
 589
 590 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
 591                                     u8 type, u8 feature)
 592 {
 593         /* XXX check if other confirms for that are queued and recycle slot */
 594         struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 595
 596         if (opt == NULL) {
 597                 /* XXX what do we do?  Ignoring should be fine.  It's a change
 598                  * after all =P
 599                  */
 600                 return;
 601         }
 602
 603         switch (type) {
 604         case DCCPO_CHANGE_L:
 605                 opt->dccpop_type = DCCPO_CONFIRM_R;
 606                 break;
 607         case DCCPO_CHANGE_R:
 608                 opt->dccpop_type = DCCPO_CONFIRM_L;
 609                 break;
 610         default:
 611                 DCCP_WARN("invalid type %d\n", type);
 612                 kfree(opt);
 613                 return;
 614         }
 615         opt->dccpop_feat = feature;
 616         opt->dccpop_val  = NULL;
 617         opt->dccpop_len  = 0;
 618
 619         /* change feature */
 620         dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
 621
 622         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 623 }
 624
 625 static void dccp_feat_flush_confirm(struct sock *sk)
 626 {
 627         struct dccp_minisock *dmsk = dccp_msk(sk);
 628         /* Check if there is anything to confirm in the first place */
 629         int yes = !list_empty(&dmsk->dccpms_conf);
 630
 631         if (!yes) {
 632                 struct dccp_opt_pend *opt;
 633
 634                 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 635                         if (opt->dccpop_conf) {
 636                                 yes = 1;
 637                                 break;
 638                         }
 639                 }
 640         }
 641
 642         if (!yes)
 643                 return;
 644
 645         /* OK there is something to confirm... */
 646         /* XXX check if packet is in flight?  Send delayed ack?? */
 647         if (sk->sk_state == DCCP_OPEN)
 648                 dccp_send_ack(sk);
 649 }
 650
 651 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 652 {
 653         int rc;
 654
 655         dccp_feat_debug(type, feature, *val);
 656
 657         /* figure out if it's SP or NN feature */
 658         switch (feature) {
 659         /* deal with SP features */
 660         case DCCPF_CCID:
 661                 rc = dccp_feat_sp(sk, type, feature, val, len);
 662                 break;
 663
 664         /* deal with NN features */
 665         case DCCPF_ACK_RATIO:
 666                 rc = dccp_feat_nn(sk, type, feature, val, len);
 667                 break;
 668
 669         /* XXX implement other features */
 670         default:
 671                 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
 672                               dccp_feat_typename(type), feature);
 673                 rc = -EFAULT;
 674                 break;
 675         }
 676
 677         /* check if there were problems changing features */
 678         if (rc) {
 679                 /* If we don't agree on SP, we sent a confirm for old value.
 680                  * However we propagate rc to caller in case option was
 681                  * mandatory
 682                  */
 683                 if (rc != DCCP_FEAT_SP_NOAGREE)
 684                         dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
 685         }
 686
 687         /* generate the confirm [if required] */
 688         dccp_feat_flush_confirm(sk);
 689
 690         return rc;
 691 }
 692
 693 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
 694
 695 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
 696                            u8 *val, u8 len)
 697 {
 698         u8 t;
 699         struct dccp_opt_pend *opt;
 700         struct dccp_minisock *dmsk = dccp_msk(sk);
 701         int found = 0;
 702         int all_confirmed = 1;
 703
 704         dccp_feat_debug(type, feature, *val);
 705
 706         /* locate our change request */
 707         switch (type) {
 708         case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
 709         case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
 710         default:              DCCP_WARN("invalid type %d\n", type);
 711                               return 1;
 712
 713         }
 714         /* XXX sanity check feature value */
 715
 716         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 717                 if (!opt->dccpop_conf && opt->dccpop_type == t &&
 718                     opt->dccpop_feat == feature) {
 719                         found = 1;
 720                         dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
 721
 722                         /* XXX do sanity check */
 723
 724                         opt->dccpop_conf = 1;
 725
 726                         /* We got a confirmation---change the option */
 727                         dccp_feat_update(sk, opt->dccpop_type,
 728                                          opt->dccpop_feat, *val);
 729
 730                         /* XXX check the return value of dccp_feat_update */
 731                         break;
 732                 }
 733
 734                 if (!opt->dccpop_conf)
 735                         all_confirmed = 0;
 736         }
 737
 738         /* fix re-transmit timer */
 739         /* XXX gotta make sure that no option negotiation occurs during
 740          * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
 741          * on.  if all options are confirmed it might kill timer which should
 742          * remain alive until close is received.
 743          */
 744         if (all_confirmed) {
 745                 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
 746                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
 747         }
 748
 749         if (!found)
 750                 dccp_pr_debug("%s(%d, ...) never requested\n",
 751                               dccp_feat_typename(type), feature);
 752         return 0;
 753 }
 754
 755 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
 756
 757 void dccp_feat_clean(struct dccp_minisock *dmsk)
 758 {
 759         struct dccp_opt_pend *opt, *next;
 760
 761         list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
 762                                  dccpop_node) {
 763                 BUG_ON(opt->dccpop_val == NULL);
 764                 kfree(opt->dccpop_val);
 765
 766                 if (opt->dccpop_sc != NULL) {
 767                         BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 768                         kfree(opt->dccpop_sc->dccpoc_val);
 769                         kfree(opt->dccpop_sc);
 770                 }
 771
 772                 kfree(opt);
 773         }
 774         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 775
 776         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
 777                 BUG_ON(opt == NULL);
 778                 if (opt->dccpop_val != NULL)
 779                         kfree(opt->dccpop_val);
 780                 kfree(opt);
 781         }
 782         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 783 }
 784
 785 EXPORT_SYMBOL_GPL(dccp_feat_clean);
 786
 787 /* this is to be called only when a listening sock creates its child.  It is
 788  * assumed by the function---the confirm is not duplicated, but rather it is
 789  * "passed on".
 790  */
 791 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
 792 {
 793         struct dccp_minisock *olddmsk = dccp_msk(oldsk);
 794         struct dccp_minisock *newdmsk = dccp_msk(newsk);
 795         struct dccp_opt_pend *opt;
 796         int rc = 0;
 797
 798         INIT_LIST_HEAD(&newdmsk->dccpms_pending);
 799         INIT_LIST_HEAD(&newdmsk->dccpms_conf);
 800
 801         list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
 802                 struct dccp_opt_pend *newopt;
 803                 /* copy the value of the option */
 804                 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
 805
 806                 if (val == NULL)
 807                         goto out_clean;
 808
 809                 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
 810                 if (newopt == NULL) {
 811                         kfree(val);
 812                         goto out_clean;
 813                 }
 814
 815                 /* insert the option */
 816                 newopt->dccpop_val = val;
 817                 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
 818
 819                 /* XXX what happens with backlogs and multiple connections at
 820                  * once...
 821                  */
 822                 /* the master socket no longer needs to worry about confirms */
 823                 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
 824
 825                 /* reset state for a new socket */
 826                 opt->dccpop_conf = 0;
 827         }
 828
 829         /* XXX not doing anything about the conf queue */
 830
 831 out:
 832         return rc;
 833
 834 out_clean:
 835         dccp_feat_clean(newdmsk);
 836         rc = -ENOMEM;
 837         goto out;
 838 }
 839
 840 EXPORT_SYMBOL_GPL(dccp_feat_clone);
 841
 842 static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
 843                             u8 *val, u8 len)
 844 {
 845         int rc = -ENOMEM;
 846         u8 *copy = kmemdup(val, len, GFP_KERNEL);
 847
 848         if (copy != NULL) {
 849                 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
 850                 if (rc)
 851                         kfree(copy);
 852         }
 853         return rc;
 854 }
 855
 856 int dccp_feat_init(struct dccp_minisock *dmsk)
 857 {
 858         int rc;
 859
 860         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 861         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 862
 863         /* CCID L */
 864         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
 865                               &dmsk->dccpms_tx_ccid, 1);
 866         if (rc)
 867                 goto out;
 868
 869         /* CCID R */
 870         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
 871                               &dmsk->dccpms_rx_ccid, 1);
 872         if (rc)
 873                 goto out;
 874
 875         /* Ack ratio */
 876         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
 877                               &dmsk->dccpms_ack_ratio, 1);
 878 out:
 879         return rc;
 880 }
 881
 882 EXPORT_SYMBOL_GPL(dccp_feat_init);
 883
 884 #ifdef CONFIG_IP_DCCP_DEBUG
 885 const char *dccp_feat_typename(const u8 type)
 886 {
 887         switch(type) {
 888         case DCCPO_CHANGE_L:  return("ChangeL");
 889         case DCCPO_CONFIRM_L: return("ConfirmL");
 890         case DCCPO_CHANGE_R:  return("ChangeR");
 891         case DCCPO_CONFIRM_R: return("ConfirmR");
 892         /* the following case must not appear in feature negotation  */
 893         default:              dccp_pr_debug("unknown type %d [BUG!]\n", type);
 894         }
 895         return NULL;
 896 }
 897
 898 EXPORT_SYMBOL_GPL(dccp_feat_typename);
 899
 900 const char *dccp_feat_name(const u8 feat)
 901 {
 902         static const char *feature_names[] = {
 903                 [DCCPF_RESERVED]        = "Reserved",
 904                 [DCCPF_CCID]            = "CCID",
 905                 [DCCPF_SHORT_SEQNOS]    = "Allow Short Seqnos",
 906                 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
 907                 [DCCPF_ECN_INCAPABLE]   = "ECN Incapable",
 908                 [DCCPF_ACK_RATIO]       = "Ack Ratio",
 909                 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
 910                 [DCCPF_SEND_NDP_COUNT]  = "Send NDP Count",
 911                 [DCCPF_MIN_CSUM_COVER]  = "Min. Csum Coverage",
 912                 [DCCPF_DATA_CHECKSUM]   = "Send Data Checksum",
 913         };
 914         if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
 915                 return feature_names[DCCPF_RESERVED];
 916
 917         if (feat ==  DCCPF_SEND_LEV_RATE)
 918                 return "Send Loss Event Rate";
 919         if (feat >= DCCPF_MIN_CCID_SPECIFIC)
 920                 return "CCID-specific";
 921
 922         return feature_names[feat];
 923 }
 924
 925 EXPORT_SYMBOL_GPL(dccp_feat_name);
 926 #endif /* CONFIG_IP_DCCP_DEBUG */