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 int dccp_feat_change(struct dccp_minisock *dmsk, u8 type, u8 feature,
  64                      u8 *val, u8 len, gfp_t gfp)
  65 {
  66         struct dccp_opt_pend *opt;
  67
  68         dccp_feat_debug(type, feature, *val);
  69
  70         if (len > 3) {
  71                 DCCP_WARN("invalid length %d\n", len);
  72                 return -EINVAL;
  73         }
  74         /* XXX add further sanity checks */
  75
  76         /* check if that feature is already being negotiated */
  77         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
  78                 /* ok we found a negotiation for this option already */
  79                 if (opt->dccpop_feat == feature && opt->dccpop_type == type) {
  80                         dccp_pr_debug("Replacing old\n");
  81                         /* replace */
  82                         BUG_ON(opt->dccpop_val == NULL);
  83                         kfree(opt->dccpop_val);
  84                         opt->dccpop_val  = val;
  85                         opt->dccpop_len  = len;
  86                         opt->dccpop_conf = 0;
  87                         return 0;
  88                 }
  89         }
  90
  91         /* negotiation for a new feature */
  92         opt = kmalloc(sizeof(*opt), gfp);
  93         if (opt == NULL)
  94                 return -ENOMEM;
  95
  96         opt->dccpop_type = type;
  97         opt->dccpop_feat = feature;
  98         opt->dccpop_len  = len;
  99         opt->dccpop_val  = val;
 100         opt->dccpop_conf = 0;
 101         opt->dccpop_sc   = NULL;
 102
 103         BUG_ON(opt->dccpop_val == NULL);
 104
 105         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_pending);
 106         return 0;
 107 }
 108
 109 EXPORT_SYMBOL_GPL(dccp_feat_change);
 110
 111 static int dccp_feat_update_ccid(struct sock *sk, u8 type, u8 new_ccid_nr)
 112 {
 113         struct dccp_sock *dp = dccp_sk(sk);
 114         struct dccp_minisock *dmsk = dccp_msk(sk);
 115         /* figure out if we are changing our CCID or the peer's */
 116         const int rx = type == DCCPO_CHANGE_R;
 117         const u8 ccid_nr = rx ? dmsk->dccpms_rx_ccid : dmsk->dccpms_tx_ccid;
 118         struct ccid *new_ccid;
 119
 120         /* Check if nothing is being changed. */
 121         if (ccid_nr == new_ccid_nr)
 122                 return 0;
 123
 124         new_ccid = ccid_new(new_ccid_nr, sk, rx, GFP_ATOMIC);
 125         if (new_ccid == NULL)
 126                 return -ENOMEM;
 127
 128         if (rx) {
 129                 ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
 130                 dp->dccps_hc_rx_ccid = new_ccid;
 131                 dmsk->dccpms_rx_ccid = new_ccid_nr;
 132         } else {
 133                 ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
 134                 dp->dccps_hc_tx_ccid = new_ccid;
 135                 dmsk->dccpms_tx_ccid = new_ccid_nr;
 136         }
 137
 138         return 0;
 139 }
 140
 141 static int dccp_feat_update(struct sock *sk, u8 type, u8 feat, u8 val)
 142 {
 143         dccp_feat_debug(type, feat, val);
 144
 145         switch (feat) {
 146         case DCCPF_CCID:
 147                 return dccp_feat_update_ccid(sk, type, val);
 148         default:
 149                 dccp_pr_debug("UNIMPLEMENTED: %s(%d, ...)\n",
 150                               dccp_feat_typename(type), feat);
 151                 break;
 152         }
 153         return 0;
 154 }
 155
 156 static int dccp_feat_reconcile(struct sock *sk, struct dccp_opt_pend *opt,
 157                                u8 *rpref, u8 rlen)
 158 {
 159         struct dccp_sock *dp = dccp_sk(sk);
 160         u8 *spref, slen, *res = NULL;
 161         int i, j, rc, agree = 1;
 162
 163         BUG_ON(rpref == NULL);
 164
 165         /* check if we are the black sheep */
 166         if (dp->dccps_role == DCCP_ROLE_CLIENT) {
 167                 spref = rpref;
 168                 slen  = rlen;
 169                 rpref = opt->dccpop_val;
 170                 rlen  = opt->dccpop_len;
 171         } else {
 172                 spref = opt->dccpop_val;
 173                 slen  = opt->dccpop_len;
 174         }
 175         /*
 176          * Now we have server preference list in spref and client preference in
 177          * rpref
 178          */
 179         BUG_ON(spref == NULL);
 180         BUG_ON(rpref == NULL);
 181
 182         /* FIXME sanity check vals */
 183
 184         /* Are values in any order?  XXX Lame "algorithm" here */
 185         for (i = 0; i < slen; i++) {
 186                 for (j = 0; j < rlen; j++) {
 187                         if (spref[i] == rpref[j]) {
 188                                 res = &spref[i];
 189                                 break;
 190                         }
 191                 }
 192                 if (res)
 193                         break;
 194         }
 195
 196         /* we didn't agree on anything */
 197         if (res == NULL) {
 198                 /* confirm previous value */
 199                 switch (opt->dccpop_feat) {
 200                 case DCCPF_CCID:
 201                         /* XXX did i get this right? =P */
 202                         if (opt->dccpop_type == DCCPO_CHANGE_L)
 203                                 res = &dccp_msk(sk)->dccpms_tx_ccid;
 204                         else
 205                                 res = &dccp_msk(sk)->dccpms_rx_ccid;
 206                         break;
 207
 208                 default:
 209                         DCCP_BUG("Fell through, feat=%d", opt->dccpop_feat);
 210                         /* XXX implement res */
 211                         return -EFAULT;
 212                 }
 213
 214                 dccp_pr_debug("Don't agree... reconfirming %d\n", *res);
 215                 agree = 0; /* this is used for mandatory options... */
 216         }
 217
 218         /* need to put result and our preference list */
 219         rlen = 1 + opt->dccpop_len;
 220         rpref = kmalloc(rlen, GFP_ATOMIC);
 221         if (rpref == NULL)
 222                 return -ENOMEM;
 223
 224         *rpref = *res;
 225         memcpy(&rpref[1], opt->dccpop_val, opt->dccpop_len);
 226
 227         /* put it in the "confirm queue" */
 228         if (opt->dccpop_sc == NULL) {
 229                 opt->dccpop_sc = kmalloc(sizeof(*opt->dccpop_sc), GFP_ATOMIC);
 230                 if (opt->dccpop_sc == NULL) {
 231                         kfree(rpref);
 232                         return -ENOMEM;
 233                 }
 234         } else {
 235                 /* recycle the confirm slot */
 236                 BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 237                 kfree(opt->dccpop_sc->dccpoc_val);
 238                 dccp_pr_debug("recycling confirm slot\n");
 239         }
 240         memset(opt->dccpop_sc, 0, sizeof(*opt->dccpop_sc));
 241
 242         opt->dccpop_sc->dccpoc_val = rpref;
 243         opt->dccpop_sc->dccpoc_len = rlen;
 244
 245         /* update the option on our side [we are about to send the confirm] */
 246         rc = dccp_feat_update(sk, opt->dccpop_type, opt->dccpop_feat, *res);
 247         if (rc) {
 248                 kfree(opt->dccpop_sc->dccpoc_val);
 249                 kfree(opt->dccpop_sc);
 250                 opt->dccpop_sc = NULL;
 251                 return rc;
 252         }
 253
 254         dccp_pr_debug("Will confirm %d\n", *rpref);
 255
 256         /* say we want to change to X but we just got a confirm X, suppress our
 257          * change
 258          */
 259         if (!opt->dccpop_conf) {
 260                 if (*opt->dccpop_val == *res)
 261                         opt->dccpop_conf = 1;
 262                 dccp_pr_debug("won't ask for change of same feature\n");
 263         }
 264
 265         return agree ? 0 : DCCP_FEAT_SP_NOAGREE; /* used for mandatory opts */
 266 }
 267
 268 static int dccp_feat_sp(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 269 {
 270         struct dccp_minisock *dmsk = dccp_msk(sk);
 271         struct dccp_opt_pend *opt;
 272         int rc = 1;
 273         u8 t;
 274
 275         /*
 276          * We received a CHANGE.  We gotta match it against our own preference
 277          * list.  If we got a CHANGE_R it means it's a change for us, so we need
 278          * to compare our CHANGE_L list.
 279          */
 280         if (type == DCCPO_CHANGE_L)
 281                 t = DCCPO_CHANGE_R;
 282         else
 283                 t = DCCPO_CHANGE_L;
 284
 285         /* find our preference list for this feature */
 286         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 287                 if (opt->dccpop_type != t || opt->dccpop_feat != feature)
 288                         continue;
 289
 290                 /* find the winner from the two preference lists */
 291                 rc = dccp_feat_reconcile(sk, opt, val, len);
 292                 break;
 293         }
 294
 295         /* We didn't deal with the change.  This can happen if we have no
 296          * preference list for the feature.  In fact, it just shouldn't
 297          * happen---if we understand a feature, we should have a preference list
 298          * with at least the default value.
 299          */
 300         BUG_ON(rc == 1);
 301
 302         return rc;
 303 }
 304
 305 static int dccp_feat_nn(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 306 {
 307         struct dccp_opt_pend *opt;
 308         struct dccp_minisock *dmsk = dccp_msk(sk);
 309         u8 *copy;
 310         int rc;
 311
 312         /* NN features must be Change L (sec. 6.3.2) */
 313         if (type != DCCPO_CHANGE_L) {
 314                 dccp_pr_debug("received %s for NN feature %d\n",
 315                                 dccp_feat_typename(type), feature);
 316                 return -EFAULT;
 317         }
 318
 319         /* XXX sanity check opt val */
 320
 321         /* copy option so we can confirm it */
 322         opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 323         if (opt == NULL)
 324                 return -ENOMEM;
 325
 326         copy = kmemdup(val, len, GFP_ATOMIC);
 327         if (copy == NULL) {
 328                 kfree(opt);
 329                 return -ENOMEM;
 330         }
 331
 332         opt->dccpop_type = DCCPO_CONFIRM_R; /* NN can only confirm R */
 333         opt->dccpop_feat = feature;
 334         opt->dccpop_val  = copy;
 335         opt->dccpop_len  = len;
 336
 337         /* change feature */
 338         rc = dccp_feat_update(sk, type, feature, *val);
 339         if (rc) {
 340                 kfree(opt->dccpop_val);
 341                 kfree(opt);
 342                 return rc;
 343         }
 344
 345         dccp_feat_debug(type, feature, *copy);
 346
 347         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 348
 349         return 0;
 350 }
 351
 352 static void dccp_feat_empty_confirm(struct dccp_minisock *dmsk,
 353                                     u8 type, u8 feature)
 354 {
 355         /* XXX check if other confirms for that are queued and recycle slot */
 356         struct dccp_opt_pend *opt = kzalloc(sizeof(*opt), GFP_ATOMIC);
 357
 358         if (opt == NULL) {
 359                 /* XXX what do we do?  Ignoring should be fine.  It's a change
 360                  * after all =P
 361                  */
 362                 return;
 363         }
 364
 365         switch (type) {
 366         case DCCPO_CHANGE_L:
 367                 opt->dccpop_type = DCCPO_CONFIRM_R;
 368                 break;
 369         case DCCPO_CHANGE_R:
 370                 opt->dccpop_type = DCCPO_CONFIRM_L;
 371                 break;
 372         default:
 373                 DCCP_WARN("invalid type %d\n", type);
 374                 kfree(opt);
 375                 return;
 376         }
 377         opt->dccpop_feat = feature;
 378         opt->dccpop_val  = NULL;
 379         opt->dccpop_len  = 0;
 380
 381         /* change feature */
 382         dccp_pr_debug("Empty %s(%d)\n", dccp_feat_typename(type), feature);
 383
 384         list_add_tail(&opt->dccpop_node, &dmsk->dccpms_conf);
 385 }
 386
 387 static void dccp_feat_flush_confirm(struct sock *sk)
 388 {
 389         struct dccp_minisock *dmsk = dccp_msk(sk);
 390         /* Check if there is anything to confirm in the first place */
 391         int yes = !list_empty(&dmsk->dccpms_conf);
 392
 393         if (!yes) {
 394                 struct dccp_opt_pend *opt;
 395
 396                 list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 397                         if (opt->dccpop_conf) {
 398                                 yes = 1;
 399                                 break;
 400                         }
 401                 }
 402         }
 403
 404         if (!yes)
 405                 return;
 406
 407         /* OK there is something to confirm... */
 408         /* XXX check if packet is in flight?  Send delayed ack?? */
 409         if (sk->sk_state == DCCP_OPEN)
 410                 dccp_send_ack(sk);
 411 }
 412
 413 int dccp_feat_change_recv(struct sock *sk, u8 type, u8 feature, u8 *val, u8 len)
 414 {
 415         int rc;
 416
 417         dccp_feat_debug(type, feature, *val);
 418
 419         /* figure out if it's SP or NN feature */
 420         switch (feature) {
 421         /* deal with SP features */
 422         case DCCPF_CCID:
 423                 rc = dccp_feat_sp(sk, type, feature, val, len);
 424                 break;
 425
 426         /* deal with NN features */
 427         case DCCPF_ACK_RATIO:
 428                 rc = dccp_feat_nn(sk, type, feature, val, len);
 429                 break;
 430
 431         /* XXX implement other features */
 432         default:
 433                 dccp_pr_debug("UNIMPLEMENTED: not handling %s(%d, ...)\n",
 434                               dccp_feat_typename(type), feature);
 435                 rc = -EFAULT;
 436                 break;
 437         }
 438
 439         /* check if there were problems changing features */
 440         if (rc) {
 441                 /* If we don't agree on SP, we sent a confirm for old value.
 442                  * However we propagate rc to caller in case option was
 443                  * mandatory
 444                  */
 445                 if (rc != DCCP_FEAT_SP_NOAGREE)
 446                         dccp_feat_empty_confirm(dccp_msk(sk), type, feature);
 447         }
 448
 449         /* generate the confirm [if required] */
 450         dccp_feat_flush_confirm(sk);
 451
 452         return rc;
 453 }
 454
 455 EXPORT_SYMBOL_GPL(dccp_feat_change_recv);
 456
 457 int dccp_feat_confirm_recv(struct sock *sk, u8 type, u8 feature,
 458                            u8 *val, u8 len)
 459 {
 460         u8 t;
 461         struct dccp_opt_pend *opt;
 462         struct dccp_minisock *dmsk = dccp_msk(sk);
 463         int found = 0;
 464         int all_confirmed = 1;
 465
 466         dccp_feat_debug(type, feature, *val);
 467
 468         /* locate our change request */
 469         switch (type) {
 470         case DCCPO_CONFIRM_L: t = DCCPO_CHANGE_R; break;
 471         case DCCPO_CONFIRM_R: t = DCCPO_CHANGE_L; break;
 472         default:              DCCP_WARN("invalid type %d\n", type);
 473                               return 1;
 474
 475         }
 476         /* XXX sanity check feature value */
 477
 478         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 479                 if (!opt->dccpop_conf && opt->dccpop_type == t &&
 480                     opt->dccpop_feat == feature) {
 481                         found = 1;
 482                         dccp_pr_debug("feature %d found\n", opt->dccpop_feat);
 483
 484                         /* XXX do sanity check */
 485
 486                         opt->dccpop_conf = 1;
 487
 488                         /* We got a confirmation---change the option */
 489                         dccp_feat_update(sk, opt->dccpop_type,
 490                                          opt->dccpop_feat, *val);
 491
 492                         /* XXX check the return value of dccp_feat_update */
 493                         break;
 494                 }
 495
 496                 if (!opt->dccpop_conf)
 497                         all_confirmed = 0;
 498         }
 499
 500         /* fix re-transmit timer */
 501         /* XXX gotta make sure that no option negotiation occurs during
 502          * connection shutdown.  Consider that the CLOSEREQ is sent and timer is
 503          * on.  if all options are confirmed it might kill timer which should
 504          * remain alive until close is received.
 505          */
 506         if (all_confirmed) {
 507                 dccp_pr_debug("clear feat negotiation timer %p\n", sk);
 508                 inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
 509         }
 510
 511         if (!found)
 512                 dccp_pr_debug("%s(%d, ...) never requested\n",
 513                               dccp_feat_typename(type), feature);
 514         return 0;
 515 }
 516
 517 EXPORT_SYMBOL_GPL(dccp_feat_confirm_recv);
 518
 519 void dccp_feat_clean(struct dccp_minisock *dmsk)
 520 {
 521         struct dccp_opt_pend *opt, *next;
 522
 523         list_for_each_entry_safe(opt, next, &dmsk->dccpms_pending,
 524                                  dccpop_node) {
 525                 BUG_ON(opt->dccpop_val == NULL);
 526                 kfree(opt->dccpop_val);
 527
 528                 if (opt->dccpop_sc != NULL) {
 529                         BUG_ON(opt->dccpop_sc->dccpoc_val == NULL);
 530                         kfree(opt->dccpop_sc->dccpoc_val);
 531                         kfree(opt->dccpop_sc);
 532                 }
 533
 534                 kfree(opt);
 535         }
 536         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 537
 538         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
 539                 BUG_ON(opt == NULL);
 540                 if (opt->dccpop_val != NULL)
 541                         kfree(opt->dccpop_val);
 542                 kfree(opt);
 543         }
 544         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 545 }
 546
 547 EXPORT_SYMBOL_GPL(dccp_feat_clean);
 548
 549 /* this is to be called only when a listening sock creates its child.  It is
 550  * assumed by the function---the confirm is not duplicated, but rather it is
 551  * "passed on".
 552  */
 553 int dccp_feat_clone(struct sock *oldsk, struct sock *newsk)
 554 {
 555         struct dccp_minisock *olddmsk = dccp_msk(oldsk);
 556         struct dccp_minisock *newdmsk = dccp_msk(newsk);
 557         struct dccp_opt_pend *opt;
 558         int rc = 0;
 559
 560         INIT_LIST_HEAD(&newdmsk->dccpms_pending);
 561         INIT_LIST_HEAD(&newdmsk->dccpms_conf);
 562
 563         list_for_each_entry(opt, &olddmsk->dccpms_pending, dccpop_node) {
 564                 struct dccp_opt_pend *newopt;
 565                 /* copy the value of the option */
 566                 u8 *val = kmemdup(opt->dccpop_val, opt->dccpop_len, GFP_ATOMIC);
 567
 568                 if (val == NULL)
 569                         goto out_clean;
 570
 571                 newopt = kmemdup(opt, sizeof(*newopt), GFP_ATOMIC);
 572                 if (newopt == NULL) {
 573                         kfree(val);
 574                         goto out_clean;
 575                 }
 576
 577                 /* insert the option */
 578                 newopt->dccpop_val = val;
 579                 list_add_tail(&newopt->dccpop_node, &newdmsk->dccpms_pending);
 580
 581                 /* XXX what happens with backlogs and multiple connections at
 582                  * once...
 583                  */
 584                 /* the master socket no longer needs to worry about confirms */
 585                 opt->dccpop_sc = NULL; /* it's not a memleak---new socket has it */
 586
 587                 /* reset state for a new socket */
 588                 opt->dccpop_conf = 0;
 589         }
 590
 591         /* XXX not doing anything about the conf queue */
 592
 593 out:
 594         return rc;
 595
 596 out_clean:
 597         dccp_feat_clean(newdmsk);
 598         rc = -ENOMEM;
 599         goto out;
 600 }
 601
 602 EXPORT_SYMBOL_GPL(dccp_feat_clone);
 603
 604 static int __dccp_feat_init(struct dccp_minisock *dmsk, u8 type, u8 feat,
 605                             u8 *val, u8 len)
 606 {
 607         int rc = -ENOMEM;
 608         u8 *copy = kmemdup(val, len, GFP_KERNEL);
 609
 610         if (copy != NULL) {
 611                 rc = dccp_feat_change(dmsk, type, feat, copy, len, GFP_KERNEL);
 612                 if (rc)
 613                         kfree(copy);
 614         }
 615         return rc;
 616 }
 617
 618 int dccp_feat_init(struct dccp_minisock *dmsk)
 619 {
 620         int rc;
 621
 622         INIT_LIST_HEAD(&dmsk->dccpms_pending);
 623         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 624
 625         /* CCID L */
 626         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_CCID,
 627                               &dmsk->dccpms_tx_ccid, 1);
 628         if (rc)
 629                 goto out;
 630
 631         /* CCID R */
 632         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_R, DCCPF_CCID,
 633                               &dmsk->dccpms_rx_ccid, 1);
 634         if (rc)
 635                 goto out;
 636
 637         /* Ack ratio */
 638         rc = __dccp_feat_init(dmsk, DCCPO_CHANGE_L, DCCPF_ACK_RATIO,
 639                               &dmsk->dccpms_ack_ratio, 1);
 640 out:
 641         return rc;
 642 }
 643
 644 EXPORT_SYMBOL_GPL(dccp_feat_init);
 645
 646 #ifdef CONFIG_IP_DCCP_DEBUG
 647 const char *dccp_feat_typename(const u8 type)
 648 {
 649         switch(type) {
 650         case DCCPO_CHANGE_L:  return("ChangeL");
 651         case DCCPO_CONFIRM_L: return("ConfirmL");
 652         case DCCPO_CHANGE_R:  return("ChangeR");
 653         case DCCPO_CONFIRM_R: return("ConfirmR");
 654         /* the following case must not appear in feature negotation  */
 655         default:              dccp_pr_debug("unknown type %d [BUG!]\n", type);
 656         }
 657         return NULL;
 658 }
 659
 660 EXPORT_SYMBOL_GPL(dccp_feat_typename);
 661
 662 const char *dccp_feat_name(const u8 feat)
 663 {
 664         static const char *feature_names[] = {
 665                 [DCCPF_RESERVED]        = "Reserved",
 666                 [DCCPF_CCID]            = "CCID",
 667                 [DCCPF_SHORT_SEQNOS]    = "Allow Short Seqnos",
 668                 [DCCPF_SEQUENCE_WINDOW] = "Sequence Window",
 669                 [DCCPF_ECN_INCAPABLE]   = "ECN Incapable",
 670                 [DCCPF_ACK_RATIO]       = "Ack Ratio",
 671                 [DCCPF_SEND_ACK_VECTOR] = "Send ACK Vector",
 672                 [DCCPF_SEND_NDP_COUNT]  = "Send NDP Count",
 673                 [DCCPF_MIN_CSUM_COVER]  = "Min. Csum Coverage",
 674                 [DCCPF_DATA_CHECKSUM]   = "Send Data Checksum",
 675         };
 676         if (feat > DCCPF_DATA_CHECKSUM && feat < DCCPF_MIN_CCID_SPECIFIC)
 677                 return feature_names[DCCPF_RESERVED];
 678
 679         if (feat ==  DCCPF_SEND_LEV_RATE)
 680                 return "Send Loss Event Rate";
 681         if (feat >= DCCPF_MIN_CCID_SPECIFIC)
 682                 return "CCID-specific";
 683
 684         return feature_names[feat];
 685 }
 686
 687 EXPORT_SYMBOL_GPL(dccp_feat_name);
 688 #endif /* CONFIG_IP_DCCP_DEBUG */