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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 Feature negotiation is coordinated with connection setup (as in TCP), wild
  10  *    changes of parameters of an established connection are not supported.
  11  *  o All currently known SP features have 1-byte quantities. If in the future
  12  *    extensions of RFCs 4340..42 define features with item lengths larger than
  13  *    one byte, a feature-specific extension of the code will be required.
  14  *
  15  *  This program is free software; you can redistribute it and/or
  16  *  modify it under the terms of the GNU General Public License
  17  *  as published by the Free Software Foundation; either version
  18  *  2 of the License, or (at your option) any later version.
  19  */
  20
  21 #include <linux/module.h>
  22
  23 #include "ccid.h"
  24 #include "feat.h"
  25
  26 #define DCCP_FEAT_SP_NOAGREE (-123)
  27
  28 static const struct {
  29         u8                      feat_num;               /* DCCPF_xxx */
  30         enum dccp_feat_type     rxtx;                   /* RX or TX  */
  31         enum dccp_feat_type     reconciliation;         /* SP or NN  */
  32         u8                      default_value;          /* as in 6.4 */
  33 /*
  34  *    Lookup table for location and type of features (from RFC 4340/4342)
  35  *  +--------------------------+----+-----+----+----+---------+-----------+
  36  *  | Feature                  | Location | Reconc. | Initial |  Section  |
  37  *  |                          | RX | TX  | SP | NN |  Value  | Reference |
  38  *  +--------------------------+----+-----+----+----+---------+-----------+
  39  *  | DCCPF_CCID               |    |  X  | X  |    |   2     | 10        |
  40  *  | DCCPF_SHORT_SEQNOS       |    |  X  | X  |    |   0     |  7.6.1    |
  41  *  | DCCPF_SEQUENCE_WINDOW    |    |  X  |    | X  | 100     |  7.5.2    |
  42  *  | DCCPF_ECN_INCAPABLE      | X  |     | X  |    |   0     | 12.1      |
  43  *  | DCCPF_ACK_RATIO          |    |  X  |    | X  |   2     | 11.3      |
  44  *  | DCCPF_SEND_ACK_VECTOR    | X  |     | X  |    |   0     | 11.5      |
  45  *  | DCCPF_SEND_NDP_COUNT     |    |  X  | X  |    |   0     |  7.7.2    |
  46  *  | DCCPF_MIN_CSUM_COVER     | X  |     | X  |    |   0     |  9.2.1    |
  47  *  | DCCPF_DATA_CHECKSUM      | X  |     | X  |    |   0     |  9.3.1    |
  48  *  | DCCPF_SEND_LEV_RATE      | X  |     | X  |    |   0     | 4342/8.4  |
  49  *  +--------------------------+----+-----+----+----+---------+-----------+
  50  */
  51 } dccp_feat_table[] = {
  52         { DCCPF_CCID,            FEAT_AT_TX, FEAT_SP, 2 },
  53         { DCCPF_SHORT_SEQNOS,    FEAT_AT_TX, FEAT_SP, 0 },
  54         { DCCPF_SEQUENCE_WINDOW, FEAT_AT_TX, FEAT_NN, 100 },
  55         { DCCPF_ECN_INCAPABLE,   FEAT_AT_RX, FEAT_SP, 0 },
  56         { DCCPF_ACK_RATIO,       FEAT_AT_TX, FEAT_NN, 2 },
  57         { DCCPF_SEND_ACK_VECTOR, FEAT_AT_RX, FEAT_SP, 0 },
  58         { DCCPF_SEND_NDP_COUNT,  FEAT_AT_TX, FEAT_SP, 0 },
  59         { DCCPF_MIN_CSUM_COVER,  FEAT_AT_RX, FEAT_SP, 0 },
  60         { DCCPF_DATA_CHECKSUM,   FEAT_AT_RX, FEAT_SP, 0 },
  61         { DCCPF_SEND_LEV_RATE,   FEAT_AT_RX, FEAT_SP, 0 },
  62 };
  63 #define DCCP_FEAT_SUPPORTED_MAX         ARRAY_SIZE(dccp_feat_table)
  64
  65 /**
  66  * dccp_feat_index  -  Hash function to map feature number into array position
  67  * Returns consecutive array index or -1 if the feature is not understood.
  68  */
  69 static int dccp_feat_index(u8 feat_num)
  70 {
  71         /* The first 9 entries are occupied by the types from RFC 4340, 6.4 */
  72         if (feat_num > DCCPF_RESERVED && feat_num <= DCCPF_DATA_CHECKSUM)
  73                 return feat_num - 1;
  74
  75         /*
  76          * Other features: add cases for new feature types here after adding
  77          * them to the above table.
  78          */
  79         switch (feat_num) {
  80         case DCCPF_SEND_LEV_RATE:
  81                         return DCCP_FEAT_SUPPORTED_MAX - 1;
  82         }
  83         return -1;
  84 }
  85
  86 static u8 dccp_feat_type(u8 feat_num)
  87 {
  88         int idx = dccp_feat_index(feat_num);
  89
  90         if (idx < 0)
  91                 return FEAT_UNKNOWN;
  92         return dccp_feat_table[idx].reconciliation;
  93 }
  94
  95 static int dccp_feat_default_value(u8 feat_num)
  96 {
  97         int idx = dccp_feat_index(feat_num);
  98         /*
  99          * There are no default values for unknown features, so encountering a
 100          * negative index here indicates a serious problem somewhere else.
 101          */
 102         DCCP_BUG_ON(idx < 0);
 103
 104         return idx < 0 ? 0 : dccp_feat_table[idx].default_value;
 105 }
 106
 107 /* copy constructor, fval must not already contain allocated memory */
 108 static int dccp_feat_clone_sp_val(dccp_feat_val *fval, u8 const *val, u8 len)
 109 {
 110         fval->sp.len = len;
 111         if (fval->sp.len > 0) {
 112                 fval->sp.vec = kmemdup(val, len, gfp_any());
 113                 if (fval->sp.vec == NULL) {
 114                         fval->sp.len = 0;
 115                         return -ENOBUFS;
 116                 }
 117         }
 118         return 0;
 119 }
 120
 121 static void dccp_feat_val_destructor(u8 feat_num, dccp_feat_val *val)
 122 {
 123         if (unlikely(val == NULL))
 124                 return;
 125         if (dccp_feat_type(feat_num) == FEAT_SP)
 126                 kfree(val->sp.vec);
 127         memset(val, 0, sizeof(*val));
 128 }
 129
 130 static struct dccp_feat_entry *
 131               dccp_feat_clone_entry(struct dccp_feat_entry const *original)
 132 {
 133         struct dccp_feat_entry *new;
 134         u8 type = dccp_feat_type(original->feat_num);
 135
 136         if (type == FEAT_UNKNOWN)
 137                 return NULL;
 138
 139         new = kmemdup(original, sizeof(struct dccp_feat_entry), gfp_any());
 140         if (new == NULL)
 141                 return NULL;
 142
 143         if (type == FEAT_SP && dccp_feat_clone_sp_val(&new->val,
 144                                                       original->val.sp.vec,
 145                                                       original->val.sp.len)) {
 146                 kfree(new);
 147                 return NULL;
 148         }
 149         return new;
 150 }
 151
 152 static void dccp_feat_entry_destructor(struct dccp_feat_entry *entry)
 153 {
 154         if (entry != NULL) {
 155                 dccp_feat_val_destructor(entry->feat_num, &entry->val);
 156                 kfree(entry);
 157         }
 158 }
 159
 160 /*
 161  * List management functions
 162  *
 163  * Feature negotiation lists rely on and maintain the following invariants:
 164  * - each feat_num in the list is known, i.e. we know its type and default value
 165  * - each feat_num/is_local combination is unique (old entries are overwritten)
 166  * - SP values are always freshly allocated
 167  * - list is sorted in increasing order of feature number (faster lookup)
 168  */
 169
 170 /**
 171  * dccp_feat_entry_new  -  Central list update routine (called by all others)
 172  * @head:  list to add to
 173  * @feat:  feature number
 174  * @local: whether the local (1) or remote feature with number @feat is meant
 175  * This is the only constructor and serves to ensure the above invariants.
 176  */
 177 static struct dccp_feat_entry *
 178               dccp_feat_entry_new(struct list_head *head, u8 feat, bool local)
 179 {
 180         struct dccp_feat_entry *entry;
 181
 182         list_for_each_entry(entry, head, node)
 183                 if (entry->feat_num == feat && entry->is_local == local) {
 184                         dccp_feat_val_destructor(entry->feat_num, &entry->val);
 185                         return entry;
 186                 } else if (entry->feat_num > feat) {
 187                         head = &entry->node;
 188                         break;
 189                 }
 190
 191         entry = kmalloc(sizeof(*entry), gfp_any());
 192         if (entry != NULL) {
 193                 entry->feat_num = feat;
 194                 entry->is_local = local;
 195                 list_add_tail(&entry->node, head);
 196         }
 197         return entry;
 198 }
 199
 200 /**
 201  * dccp_feat_push_change  -  Add/overwrite a Change option in the list
 202  * @fn_list: feature-negotiation list to update
 203  * @feat: one of %dccp_feature_numbers
 204  * @local: whether local (1) or remote (0) @feat_num is meant
 205  * @needs_mandatory: whether to use Mandatory feature negotiation options
 206  * @fval: pointer to NN/SP value to be inserted (will be copied)
 207  */
 208 static int dccp_feat_push_change(struct list_head *fn_list, u8 feat, u8 local,
 209                                  u8 mandatory, dccp_feat_val *fval)
 210 {
 211         struct dccp_feat_entry *new = dccp_feat_entry_new(fn_list, feat, local);
 212
 213         if (new == NULL)
 214                 return -ENOMEM;
 215
 216         new->feat_num        = feat;
 217         new->is_local        = local;
 218         new->state           = FEAT_INITIALISING;
 219         new->needs_confirm   = 0;
 220         new->empty_confirm   = 0;
 221         new->val             = *fval;
 222         new->needs_mandatory = mandatory;
 223
 224         return 0;
 225 }
 226
 227 static inline void dccp_feat_list_pop(struct dccp_feat_entry *entry)
 228 {
 229         list_del(&entry->node);
 230         dccp_feat_entry_destructor(entry);
 231 }
 232
 233 void dccp_feat_list_purge(struct list_head *fn_list)
 234 {
 235         struct dccp_feat_entry *entry, *next;
 236
 237         list_for_each_entry_safe(entry, next, fn_list, node)
 238                 dccp_feat_entry_destructor(entry);
 239         INIT_LIST_HEAD(fn_list);
 240 }
 241 EXPORT_SYMBOL_GPL(dccp_feat_list_purge);
 242
 243 /* generate @to as full clone of @from - @to must not contain any nodes */
 244 int dccp_feat_clone_list(struct list_head const *from, struct list_head *to)
 245 {
 246         struct dccp_feat_entry *entry, *new;
 247
 248         INIT_LIST_HEAD(to);
 249         list_for_each_entry(entry, from, node) {
 250                 new = dccp_feat_clone_entry(entry);
 251                 if (new == NULL)
 252                         goto cloning_failed;
 253                 list_add_tail(&new->node, to);
 254         }
 255         return 0;
 256
 257 cloning_failed:
 258         dccp_feat_list_purge(to);
 259         return -ENOMEM;
 260 }
 261
 262 static u8 dccp_feat_is_valid_nn_val(u8 feat_num, u64 val)
 263 {
 264         switch (feat_num) {
 265         case DCCPF_ACK_RATIO:
 266                 return val <= DCCPF_ACK_RATIO_MAX;
 267         case DCCPF_SEQUENCE_WINDOW:
 268                 return val >= DCCPF_SEQ_WMIN && val <= DCCPF_SEQ_WMAX;
 269         }
 270         return 0;       /* feature unknown - so we can't tell */
 271 }
 272
 273 /* check that SP values are within the ranges defined in RFC 4340 */
 274 static u8 dccp_feat_is_valid_sp_val(u8 feat_num, u8 val)
 275 {
 276         switch (feat_num) {
 277         case DCCPF_CCID:
 278                 return val == DCCPC_CCID2 || val == DCCPC_CCID3;
 279         /* Type-check Boolean feature values: */
 280         case DCCPF_SHORT_SEQNOS:
 281         case DCCPF_ECN_INCAPABLE:
 282         case DCCPF_SEND_ACK_VECTOR:
 283         case DCCPF_SEND_NDP_COUNT:
 284         case DCCPF_DATA_CHECKSUM:
 285         case DCCPF_SEND_LEV_RATE:
 286                 return val < 2;
 287         case DCCPF_MIN_CSUM_COVER:
 288                 return val < 16;
 289         }
 290         return 0;                       /* feature unknown */
 291 }
 292
 293 static u8 dccp_feat_sp_list_ok(u8 feat_num, u8 const *sp_list, u8 sp_len)
 294 {
 295         if (sp_list == NULL || sp_len < 1)
 296                 return 0;
 297         while (sp_len--)
 298                 if (!dccp_feat_is_valid_sp_val(feat_num, *sp_list++))
 299                         return 0;
 300         return 1;
 301 }
 302
 303 /**
 304  * __feat_register_nn  -  Register new NN value on socket
 305  * @fn: feature-negotiation list to register with
 306  * @feat: an NN feature from %dccp_feature_numbers
 307  * @mandatory: use Mandatory option if 1
 308  * @nn_val: value to register (restricted to 4 bytes)
 309  * Note that NN features are local by definition (RFC 4340, 6.3.2).
 310  */
 311 static int __feat_register_nn(struct list_head *fn, u8 feat,
 312                               u8 mandatory, u64 nn_val)
 313 {
 314         dccp_feat_val fval = { .nn = nn_val };
 315
 316         if (dccp_feat_type(feat) != FEAT_NN ||
 317             !dccp_feat_is_valid_nn_val(feat, nn_val))
 318                 return -EINVAL;
 319
 320         /* Don't bother with default values, they will be activated anyway. */
 321         if (nn_val - (u64)dccp_feat_default_value(feat) == 0)
 322                 return 0;
 323
 324         return dccp_feat_push_change(fn, feat, 1, mandatory, &fval);
 325 }
 326
 327 /**
 328  * __feat_register_sp  -  Register new SP value/list on socket
 329  * @fn: feature-negotiation list to register with
 330  * @feat: an SP feature from %dccp_feature_numbers
 331  * @is_local: whether the local (1) or the remote (0) @feat is meant
 332  * @mandatory: use Mandatory option if 1
 333  * @sp_val: SP value followed by optional preference list
 334  * @sp_len: length of @sp_val in bytes
 335  */
 336 static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local,
 337                               u8 mandatory, u8 const *sp_val, u8 sp_len)
 338 {
 339         dccp_feat_val fval;
 340
 341         if (dccp_feat_type(feat) != FEAT_SP ||
 342             !dccp_feat_sp_list_ok(feat, sp_val, sp_len))
 343                 return -EINVAL;
 344
 345         if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len))
 346                 return -ENOMEM;
 347
 348         return dccp_feat_push_change(fn, feat, is_local, mandatory, &fval);
 349 }
 350
 351 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
 352                      u8 *val, u8 len, gfp_t gfp)
 353 {
 354         struct dccp_opt_pend *opt;
 355
 356         dccp_feat_debug(type, feature, *val);
 357
 358         if (len > 3) {
 359                 DCCP_WARN("invalid length %d\n", len);
 360                 return -EINVAL;
 361         }
 362         /* XXX add further sanity checks */
 363
 364         /* check if that feature is already being negotiated */
 365         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 366                 /* ok we found a negotiation for this option already */
 367                 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
 368                         dccp_pr_debug("Replacing old\n");
 369                         /* replace */
 370                         BUG_ON(opt->dccpop_val == NULL);
 371                         kfree(opt->dccpop_val);
 372                         opt->dccpop_val  = val;
 373                         opt->dccpop_len  = len;
 374                         opt->dccpop_conf = 0;
 375                         return 0;
 376                 }
 377         }
 378
 379         /* negotiation for a new feature */
 380         opt = kmalloc(sizeof(*opt), gfp);
 381         if (opt == NULL)
 382                 return -ENOMEM;
 383
 384         opt->dccpop_type = type;
 385         opt->dccpop_feat = feature;
 386         opt->dccpop_len  = len;
 387         opt->dccpop_val  = val;
 388         opt->dccpop_conf = 0;
 389         opt->dccpop_sc   = NULL;
 390
 391         BUG_ON(opt->dccpop_val == NULL);
 392
 393         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
 394         return 0;
 395 }
 396
 397 EXPORT_SYMBOL_GPL(dccp_feat_change);
 398
 399 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
 400 {
 401         struct dccp_sock *dp = dccp_sk(sk);
 402         struct dccp_minisock *dmsk = dccp_msk(sk);
 403         /* figure out if we are changing our CCID or the peer's */
 404         const int rx = type == DCCPO_CHANGE_R;
 405         const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
 406         struct ccid *new_ccid;
 407
 408         /* Check if nothing is being changed. */
 409         if (ccid_nr == new_ccid_nr)
 410                 return 0;
 411
 412         new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
 413         if (new_ccid == NULL)
 414                 return -ENOMEM;
 415
 416         if (rx) {
 417                 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
 418                 dp->dccps_hc_rx_ccid = new_ccid;
 419                 dmsk->dccpms_rx_ccid = new_ccid_nr;
 420         } else {
 421                 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 422                 dp->dccps_hc_tx_ccid = new_ccid;
 423                 dmsk->dccpms_tx_ccid = new_ccid_nr;
 424         }
 425
 426         return 0;
 427 }
 428
 429 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
 430 {
 431         dccp_feat_debug(type, feat, val);
 432
 433         switch (feat) {
 434         case DCCPF_CCID:
 435                 return dccp_feat_update_ccid(sk, type, val);
 436         default:
 437                 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
 438                               dccp_feat_typename(type), feat);
 439                 break;
 440         }
 441         return 0;
 442 }
 443
 444 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
 445                                u8 *rpref, u8 rlen)
 446 {
 447         struct dccp_sock *dp = dccp_sk(sk);
 448         u8 *spref, slen, *res = NULL;
 449         int i, j, rc, agree = 1;
 450
 451         BUG_ON(rpref == NULL);
 452
 453         /* check if we are the black sheep */
 454         if (dp->dccps_role == DCCP_ROLE_CLIENT) {
 455                 spref = rpref;
 456                 slen  = rlen;
 457                 rpref = opt->dccpop_val;
 458                 rlen  = opt->dccpop_len;
 459         } else {
 460                 spref = opt->dccpop_val;
 461                 slen  = opt->dccpop_len;
 462         }
 463         /*
 464          * Now we have server preference list in spref and client preference in
 465          * rpref
 466          */
 467         BUG_ON(spref == NULL);
 468         BUG_ON(rpref == NULL);
 469
 470         /* FIXME sanity check vals */
 471
 472         /* Are values in any order?  XXX Lame "algorithm" here */
 473         for (i = 0; i < slen; i++) {
 474                 for (j = 0; j < rlen; j++) {
 475                         if (spref[i] == rpref[j]) {
 476                                 res = &spref[i];
 477                                 break;
 478                         }
 479                 }
 480                 if (res)
 481                         break;
 482         }
 483
 484         /* we didn't agree on anything */
 485         if (res == NULL) {
 486                 /* confirm previous value */
 487                 switch (opt->dccpop_feat) {
 488                 case DCCPF_CCID:
 489                         /* XXX did i get this right? =P */
 490                         if (opt->dccpop_type == DCCPO_CHANGE_L)
 491                                 res = &dccp_msk(sk)->dccpms_tx_ccid;
 492                         else
 493                                 res = &dccp_msk(sk)->dccpms_rx_ccid;
 494                         break;
 495
 496                 default:
 497                         DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
 498                         /* XXX implement res */
 499                         return -EFAULT;
 500                 }
 501
 502                 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
 503                 agree = 0; /* this is used for mandatory options... */
 504         }
 505
 506         /* need to put result and our preference list */
 507         rlen = 1 + opt->dccpop_len;
 508         rpref = kmalloc(rlen, GFP_ATOMIC);
 509         if (rpref == NULL)
 510                 return -ENOMEM;
 511
 512         *rpref = *res;
 513         memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
 514
 515         /* put it in the "confirm queue" */
 516         if (opt->dccpop_sc == NULL) {
 517                 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
 518                 if (opt->dccpop_sc == NULL) {
 519                         kfree(rpref);
 520                         return -ENOMEM;
 521                 }
 522         } else {
 523                 /* recycle the confirm slot */
 524                 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 525                 kfree(opt->dccpop_sc->dccpoc_val);
 526                 dccp_pr_debug("recycling confirm slot\n");
 527         }
 528         memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
 529
 530         opt->dccpop_sc->dccpoc_val = rpref;
 531         opt->dccpop_sc->dccpoc_len = rlen;
 532
 533         /* update the option on our side [we are about to send the confirm] */
 534         rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
 535         if (rc) {
 536                 kfree(opt->dccpop_sc->dccpoc_val);
 537                 kfree(opt->dccpop_sc);
 538                 opt->dccpop_sc = NULL;
 539                 return rc;
 540         }
 541
 542         dccp_pr_debug("Will confirm %d\n", *rpref);
 543
 544         /* say we want to change to X but we just got a confirm X, suppress our
 545          * change
 546          */
 547         if (!opt->dccpop_conf) {
 548                 if (*opt->dccpop_val == *res)
 549                         opt->dccpop_conf = 1;
 550                 dccp_pr_debug("won't ask for change of same feature\n");
 551         }
 552
 553         return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
 554 }
 555
 556 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 557 {
 558         struct dccp_minisock *dmsk = dccp_msk(sk);
 559         struct dccp_opt_pend *opt;
 560         int rc = 1;
 561         u8 t;
 562
 563         /*
 564          * We received a CHANGE.  We gotta match it against our own preference
 565          * list.  If we got a CHANGE_R it means it's a change for us, so we need
 566          * to compare our CHANGE_L list.
 567          */
 568         if (type == DCCPO_CHANGE_L)
 569                 t = DCCPO_CHANGE_R;
 570         else
 571                 t = DCCPO_CHANGE_L;
 572
 573         /* find our preference list for this feature */
 574         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 575                 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
 576                         continue;
 577
 578                 /* find the winner from the two preference lists */
 579                 rc = dccp_feat_reconcile(sk, opt, val, len);
 580                 break;
 581         }
 582
 583         /* We didn't deal with the change.  This can happen if we have no
 584          * preference list for the feature.  In fact, it just shouldn't
 585          * happen---if we understand a feature, we should have a preference list
 586          * with at least the default value.
 587          */
 588         BUG_ON(rc == 1);
 589
 590         return rc;
 591 }
 592
 593 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 594 {
 595         struct dccp_opt_pend *opt;
 596         struct dccp_minisock *dmsk = dccp_msk(sk);
 597         u8 *copy;
 598         int rc;
 599
 600         /* NN features must be Change L (sec. 6.3.2) */
 601         if (type != DCCPO_CHANGE_L) {
 602                 dccp_pr_debug("received %s for NN feature %d\n",
 603                                 dccp_feat_typename(type), feature);
 604                 return -EFAULT;
 605         }
 606
 607         /* XXX sanity check opt val */
 608
 609         /* copy option so we can confirm it */
 610         opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 611         if (opt == NULL)
 612                 return -ENOMEM;
 613
 614         copy = kmemdup(val, len, GFP_ATOMIC);
 615         if (copy == NULL) {
 616                 kfree(opt);
 617                 return -ENOMEM;
 618         }
 619
 620         opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
 621         opt->dccpop_feat = feature;
 622         opt->dccpop_val  = copy;
 623         opt->dccpop_len  = len;
 624
 625         /* change feature */
 626         rc = dccp_feat_update(sk, type, feature, *val);
 627         if (rc) {
 628                 kfree(opt->dccpop_val);
 629                 kfree(opt);
 630                 return rc;
 631         }
 632
 633         dccp_feat_debug(type, feature, *copy);
 634
 635         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 636
 637         return 0;
 638 }
 639
 640 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
 641                                     u8 type, u8 feature)
 642 {
 643         /* XXX check if other confirms for that are queued and recycle slot */
 644         struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 645
 646         if (opt == NULL) {
 647                 /* XXX what do we do?  Ignoring should be fine.  It's a change
 648                  * after all =P
 649                  */
 650                 return;
 651         }
 652
 653         switch (type) {
 654         case DCCPO_CHANGE_L:
 655                 opt->dccpop_type = DCCPO_CONFIRM_R;
 656                 break;
 657         case DCCPO_CHANGE_R:
 658                 opt->dccpop_type = DCCPO_CONFIRM_L;
 659                 break;
 660         default:
 661                 DCCP_WARN("invalid type %d\n", type);
 662                 kfree(opt);
 663                 return;
 664         }
 665         opt->dccpop_feat = feature;
 666         opt->dccpop_val  = NULL;
 667         opt->dccpop_len  = 0;
 668
 669         /* change feature */
 670         dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
 671
 672         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 673 }
 674
 675 static void dccp_feat_flush_confirm(struct sock *sk)
 676 {
 677         struct dccp_minisock *dmsk = dccp_msk(sk);
 678         /* Check if there is anything to confirm in the first place */
 679         int yes = !list_empty(&dmsk->dccpms_conf);
 680
 681         if (!yes) {
 682                 struct dccp_opt_pend *opt;
 683
 684                 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 685                         if (opt->dccpop_conf) {
 686                                 yes = 1;
 687                                 break;
 688                         }
 689                 }
 690         }
 691
 692         if (!yes)
 693                 return;
 694
 695         /* OK there is something to confirm... */
 696         /* XXX check if packet is in flight?  Send delayed ack?? */
 697         if (sk->sk_state == DCCP_OPEN)
 698                 dccp_send_ack(sk);
 699 }
 700
 701 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 702 {
 703         int rc;
 704
 705         /* Ignore Change requests other than during connection setup */
 706         if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
 707                 return 0;
 708         dccp_feat_debug(type, feature, *val);
 709
 710         /* figure out if it's SP or NN feature */
 711         switch (feature) {
 712         /* deal with SP features */
 713         case DCCPF_CCID:
 714                 rc = dccp_feat_sp(sk, type, feature, val, len);
 715                 break;
 716
 717         /* deal with NN features */
 718         case DCCPF_ACK_RATIO:
 719                 rc = dccp_feat_nn(sk, type, feature, val, len);
 720                 break;
 721
 722         /* XXX implement other features */
 723         default:
 724                 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
 725                               dccp_feat_typename(type), feature);
 726                 rc = -EFAULT;
 727                 break;
 728         }
 729
 730         /* check if there were problems changing features */
 731         if (rc) {
 732                 /* If we don't agree on SP, we sent a confirm for old value.
 733                  * However we propagate rc to caller in case option was
 734                  * mandatory
 735                  */
 736                 if (rc != DCCP_FEAT_SP_NOAGREE)
 737                         dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
 738         }
 739
 740         /* generate the confirm [if required] */
 741         dccp_feat_flush_confirm(sk);
 742
 743         return rc;
 744 }
 745
 746 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
 747
 748 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
 749                            u8 *val, u8 len)
 750 {
 751         u8 t;
 752         struct dccp_opt_pend *opt;
 753         struct dccp_minisock *dmsk = dccp_msk(sk);
 754         int found = 0;
 755         int all_confirmed = 1;
 756
 757         /* Ignore Confirm options other than during connection setup */
 758         if (sk->sk_state != DCCP_LISTEN && sk->sk_state != DCCP_REQUESTING)
 759                 return 0;
 760         dccp_feat_debug(type, feature, *val);
 761
 762         /* locate our change request */
 763         switch (type) {
 764         case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
 765         case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
 766         default:              DCCP_WARN("invalid type %d\n", type);
 767                               return 1;
 768
 769         }
 770         /* XXX sanity check feature value */
 771
 772         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 773                 if (!opt->dccpop_conf && opt->dccpop_type == t &&
 774                     opt->dccpop_feat == feature) {
 775                         found = 1;
 776                         dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
 777
 778                         /* XXX do sanity check */
 779
 780                         opt->dccpop_conf = 1;
 781
 782                         /* We got a confirmation---change the option */
 783                         dccp_feat_update(sk, opt->dccpop_type,
 784                                          opt->dccpop_feat, *val);
 785
 786                         /* XXX check the return value of dccp_feat_update */
 787                         break;
 788                 }
 789
 790                 if (!opt->dccpop_conf)
 791                         all_confirmed = 0;
 792         }
 793
 794         if (!found)
 795                 dccp_pr_debug("%s(%d, ...) never requested\n",
 796                               dccp_feat_typename(type), feature);
 797         return 0;
 798 }
 799
 800 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
 801
 802 void dccp_feat_clean(struct dccp_minisock *dmsk)
 803 {
 804         struct dccp_opt_pend *opt, *next;
 805
 806         list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
 807                                  dccpop_node) {
 808                 BUG_ON(opt->dccpop_val == NULL);
 809                 kfree(opt->dccpop_val);
 810
 811                 if (opt->dccpop_sc != NULL) {
 812                         BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 813                         kfree(opt->dccpop_sc->dccpoc_val);
 814                         kfree(opt->dccpop_sc);
 815                 }
 816
 817                 kfree(opt);
 818         }
 819         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 820
 821         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
 822                 BUG_ON(opt == NULL);
 823                 if (opt->dccpop_val != NULL)
 824                         kfree(opt->dccpop_val);
 825                 kfree(opt);
 826         }
 827         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 828 }
 829
 830 EXPORT_SYMBOL_GPL(dccp_feat_clean);
 831
 832 /* this is to be called only when a listening sock creates its child.  It is
 833  * assumed by the function---the confirm is not duplicated, but rather it is
 834  * "passed on".
 835  */
 836 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
 837 {
 838         struct dccp_minisock *olddmsk = dccp_msk(oldsk);
 839         struct dccp_minisock *newdmsk = dccp_msk(newsk);
 840         struct dccp_opt_pend *opt;
 841         int rc = 0;
 842
 843         INIT_LIST_HEAD(&newdmsk->dccpms_pending);
 844         INIT_LIST_HEAD(&newdmsk->dccpms_conf);
 845
 846         list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
 847                 struct dccp_opt_pend *newopt;
 848                 /* copy the value of the option */
 849                 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
 850
 851                 if (val == NULL)
 852                         goto out_clean;
 853
 854                 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
 855                 if (newopt == NULL) {
 856                         kfree(val);
 857                         goto out_clean;
 858                 }
 859
 860                 /* insert the option */
 861                 newopt->dccpop_val = val;
 862                 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
 863
 864                 /* XXX what happens with backlogs and multiple connections at
 865                  * once...
 866                  */
 867                 /* the master socket no longer needs to worry about confirms */
 868                 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
 869
 870                 /* reset state for a new socket */
 871                 opt->dccpop_conf = 0;
 872         }
 873
 874         /* XXX not doing anything about the conf queue */
 875
 876 out:
 877         return rc;
 878
 879 out_clean:
 880         dccp_feat_clean(newdmsk);
 881         rc = -ENOMEM;
 882         goto out;
 883 }
 884
 885 EXPORT_SYMBOL_GPL(dccp_feat_clone);
 886
 887 int dccp_feat_init(struct sock *sk)
 888 {
 889         struct dccp_sock *dp = dccp_sk(sk);
 890         struct dccp_minisock *dmsk = dccp_msk(sk);
 891         int rc;
 892
 893         INIT_LIST_HEAD(&dmsk->dccpms_pending);  /* XXX no longer used */
 894         INIT_LIST_HEAD(&dmsk->dccpms_conf);     /* XXX no longer used */
 895
 896         /* CCID L */
 897         rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 1, 0,
 898                                 &dmsk->dccpms_tx_ccid, 1);
 899         if (rc)
 900                 goto out;
 901
 902         /* CCID R */
 903         rc = __feat_register_sp(&dp->dccps_featneg, DCCPF_CCID, 0, 0,
 904                                 &dmsk->dccpms_rx_ccid, 1);
 905         if (rc)
 906                 goto out;
 907
 908         /* Ack ratio */
 909         rc = __feat_register_nn(&dp->dccps_featneg, DCCPF_ACK_RATIO, 0,
 910                                 dmsk->dccpms_ack_ratio);
 911 out:
 912         return rc;
 913 }
 914
 915 EXPORT_SYMBOL_GPL(dccp_feat_init);
 916
 917 #ifdef CONFIG_IP_DCCP_DEBUG
 918 const char *dccp_feat_typename(const u8 type)
 919 {
 920         switch(type) {
 921         case DCCPO_CHANGE_L:  return("ChangeL");
 922         case DCCPO_CONFIRM_L: return("ConfirmL");
 923         case DCCPO_CHANGE_R:  return("ChangeR");
 924         case DCCPO_CONFIRM_R: return("ConfirmR");
 925         /* the following case must not appear in feature negotation  */
 926         default:              dccp_pr_debug("unknown type %d [BUG!]\n", type);
 927         }
 928         return NULL;
 929 }
 930
 931 EXPORT_SYMBOL_GPL(dccp_feat_typename);
 932
 933 const char *dccp_feat_name(const u8 feat)
 934 {
 935         static const char *feature_names[] = {
 936                 [DCCPF_RESERVED]        = "Reserved",
 937                 [DCCPF_CCID]            = "CCID",
 938                 [DCCPF_SHORT_SEQNOS]    = "Allow Short Seqnos",
 939                 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
 940                 [DCCPF_ECN_INCAPABLE]   = "ECN Incapable",
 941                 [DCCPF_ACK_RATIO]       = "Ack Ratio",
 942                 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
 943                 [DCCPF_SEND_NDP_COUNT]  = "Send NDP Count",
 944                 [DCCPF_MIN_CSUM_COVER]  = "Min. Csum Coverage",
 945                 [DCCPF_DATA_CHECKSUM]   = "Send Data Checksum",
 946         };
 947         if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
 948                 return feature_names[DCCPF_RESERVED];
 949
 950         if (feat ==  DCCPF_SEND_LEV_RATE)
 951                 return "Send Loss Event Rate";
 952         if (feat >= DCCPF_MIN_CCID_SPECIFIC)
 953                 return "CCID-specific";
 954
 955         return feature_names[feat];
 956 }
 957
 958 EXPORT_SYMBOL_GPL(dccp_feat_name);
 959 #endif /* CONFIG_IP_DCCP_DEBUG */