err.no Git - linux-2.6/blob - net/dccp/options.c

   1 /*
   2  *  net/dccp/options.c
   3  *
   4  *  An implementation of the DCCP protocol
   5  *  Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
   6  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
   7  *  Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  */
  14 #include <linux/dccp.h>
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/skbuff.h>
  19
  20 #include "ackvec.h"
  21 #include "ccid.h"
  22 #include "dccp.h"
  23 #include "feat.h"
  24
  25 int sysctl_dccp_feat_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW;
  26 int sysctl_dccp_feat_rx_ccid          = DCCPF_INITIAL_CCID;
  27 int sysctl_dccp_feat_tx_ccid          = DCCPF_INITIAL_CCID;
  28 int sysctl_dccp_feat_ack_ratio        = DCCPF_INITIAL_ACK_RATIO;
  29 int sysctl_dccp_feat_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR;
  30 int sysctl_dccp_feat_send_ndp_count  = DCCPF_INITIAL_SEND_NDP_COUNT;
  31
  32 void dccp_minisock_init(struct dccp_minisock *dmsk)
  33 {
  34         dmsk->dccpms_sequence_window = sysctl_dccp_feat_sequence_window;
  35         dmsk->dccpms_rx_ccid         = sysctl_dccp_feat_rx_ccid;
  36         dmsk->dccpms_tx_ccid         = sysctl_dccp_feat_tx_ccid;
  37         dmsk->dccpms_ack_ratio       = sysctl_dccp_feat_ack_ratio;
  38         dmsk->dccpms_send_ack_vector = sysctl_dccp_feat_send_ack_vector;
  39         dmsk->dccpms_send_ndp_count  = sysctl_dccp_feat_send_ndp_count;
  40 }
  41
  42 static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
  43 {
  44         u32 value = 0;
  45
  46         if (len > 3)
  47                 value += *bf++ << 24;
  48         if (len > 2)
  49                 value += *bf++ << 16;
  50         if (len > 1)
  51                 value += *bf++ << 8;
  52         if (len > 0)
  53                 value += *bf;
  54
  55         return value;
  56 }
  57
  58 int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
  59 {
  60         struct dccp_sock *dp = dccp_sk(sk);
  61         const struct dccp_hdr *dh = dccp_hdr(skb);
  62         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
  63         u64 ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
  64         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
  65         unsigned char *opt_ptr = options;
  66         const unsigned char *opt_end = (unsigned char *)dh +
  67                                         (dh->dccph_doff * 4);
  68         struct dccp_options_received *opt_recv = &dp->dccps_options_received;
  69         unsigned char opt, len;
  70         unsigned char *value;
  71         u32 elapsed_time;
  72         int rc;
  73         int mandatory = 0;
  74
  75         memset(opt_recv, 0, sizeof(*opt_recv));
  76
  77         opt = len = 0;
  78         while (opt_ptr != opt_end) {
  79                 opt   = *opt_ptr++;
  80                 len   = 0;
  81                 value = NULL;
  82
  83                 /* Check if this isn't a single byte option */
  84                 if (opt > DCCPO_MAX_RESERVED) {
  85                         if (opt_ptr == opt_end)
  86                                 goto out_invalid_option;
  87
  88                         len = *opt_ptr++;
  89                         if (len < 3)
  90                                 goto out_invalid_option;
  91                         /*
  92                          * Remove the type and len fields, leaving
  93                          * just the value size
  94                          */
  95                         len     -= 2;
  96                         value   = opt_ptr;
  97                         opt_ptr += len;
  98
  99                         if (opt_ptr > opt_end)
 100                                 goto out_invalid_option;
 101                 }
 102
 103                 switch (opt) {
 104                 case DCCPO_PADDING:
 105                         break;
 106                 case DCCPO_MANDATORY:
 107                         if (mandatory)
 108                                 goto out_invalid_option;
 109                         if (pkt_type != DCCP_PKT_DATA)
 110                                 mandatory = 1;
 111                         break;
 112                 case DCCPO_NDP_COUNT:
 113                         if (len > 3)
 114                                 goto out_invalid_option;
 115
 116                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
 117                         dccp_pr_debug("%s rx opt: NDP count=%d\n", dccp_role(sk),
 118                                       opt_recv->dccpor_ndp);
 119                         break;
 120                 case DCCPO_CHANGE_L:
 121                         /* fall through */
 122                 case DCCPO_CHANGE_R:
 123                         if (len < 2)
 124                                 goto out_invalid_option;
 125                         rc = dccp_feat_change_recv(sk, opt, *value, value + 1,
 126                                                    len - 1);
 127                         /*
 128                          * When there is a change error, change_recv is
 129                          * responsible for dealing with it.  i.e. reply with an
 130                          * empty confirm.
 131                          * If the change was mandatory, then we need to die.
 132                          */
 133                         if (rc && mandatory)
 134                                 goto out_invalid_option;
 135                         break;
 136                 case DCCPO_CONFIRM_L:
 137                         /* fall through */
 138                 case DCCPO_CONFIRM_R:
 139                         if (len < 2)
 140                                 goto out_invalid_option;
 141                         if (dccp_feat_confirm_recv(sk, opt, *value,
 142                                                    value + 1, len - 1))
 143                                 goto out_invalid_option;
 144                         break;
 145                 case DCCPO_ACK_VECTOR_0:
 146                 case DCCPO_ACK_VECTOR_1:
 147                         if (pkt_type == DCCP_PKT_DATA)
 148                                 break;
 149
 150                         if (dccp_msk(sk)->dccpms_send_ack_vector &&
 151                             dccp_ackvec_parse(sk, skb, &ackno, opt, value, len))
 152                                 goto out_invalid_option;
 153                         break;
 154                 case DCCPO_TIMESTAMP:
 155                         if (len != 4)
 156                                 goto out_invalid_option;
 157
 158                         opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
 159
 160                         dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
 161                         dccp_timestamp(sk, &dp->dccps_timestamp_time);
 162
 163                         dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
 164                                       dccp_role(sk), opt_recv->dccpor_timestamp,
 165                                       (unsigned long long)
 166                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 167                         break;
 168                 case DCCPO_TIMESTAMP_ECHO:
 169                         if (len != 4 && len != 6 && len != 8)
 170                                 goto out_invalid_option;
 171
 172                         opt_recv->dccpor_timestamp_echo = ntohl(*(__be32 *)value);
 173
 174                         dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
 175                                       "ackno=%llu, ",  dccp_role(sk),
 176                                       opt_recv->dccpor_timestamp_echo,
 177                                       len + 2,
 178                                       (unsigned long long)
 179                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 180
 181
 182                         if (len == 4)
 183                                 break;
 184
 185                         if (len == 6)
 186                                 elapsed_time = ntohs(*(__be16 *)(value + 4));
 187                         else
 188                                 elapsed_time = ntohl(*(__be32 *)(value + 4));
 189
 190                         /* Give precedence to the biggest ELAPSED_TIME */
 191                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 192                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 193                         break;
 194                 case DCCPO_ELAPSED_TIME:
 195                         if (len != 2 && len != 4)
 196                                 goto out_invalid_option;
 197
 198                         if (pkt_type == DCCP_PKT_DATA)
 199                                 continue;
 200
 201                         if (len == 2)
 202                                 elapsed_time = ntohs(*(__be16 *)value);
 203                         else
 204                                 elapsed_time = ntohl(*(__be32 *)value);
 205
 206                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 207                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 208
 209                         dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
 210                                       dccp_role(sk), elapsed_time);
 211                         break;
 212                         /*
 213                          * From RFC 4340, sec. 10.3:
 214                          *
 215                          *      Option numbers 128 through 191 are for
 216                          *      options sent from the HC-Sender to the
 217                          *      HC-Receiver; option numbers 192 through 255
 218                          *      are for options sent from the HC-Receiver to
 219                          *      the HC-Sender.
 220                          */
 221                 case 128 ... 191: {
 222                         const u16 idx = value - options;
 223
 224                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
 225                                                      opt, len, idx,
 226                                                      value) != 0)
 227                                 goto out_invalid_option;
 228                 }
 229                         break;
 230                 case 192 ... 255: {
 231                         const u16 idx = value - options;
 232
 233                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
 234                                                      opt, len, idx,
 235                                                      value) != 0)
 236                                 goto out_invalid_option;
 237                 }
 238                         break;
 239                 default:
 240                         DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
 241                                   "implemented, ignoring", sk, opt, len);
 242                         break;
 243                 }
 244
 245                 if (opt != DCCPO_MANDATORY)
 246                         mandatory = 0;
 247         }
 248
 249         /* mandatory was the last byte in option list -> reset connection */
 250         if (mandatory)
 251                 goto out_invalid_option;
 252
 253         return 0;
 254
 255 out_invalid_option:
 256         DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
 257         DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
 258         DCCP_WARN("DCCP(%p): invalid option %d, len=%d", sk, opt, len);
 259         return -1;
 260 }
 261
 262 EXPORT_SYMBOL_GPL(dccp_parse_options);
 263
 264 static void dccp_encode_value_var(const u32 value, unsigned char *to,
 265                                   const unsigned int len)
 266 {
 267         if (len > 3)
 268                 *to++ = (value & 0xFF000000) >> 24;
 269         if (len > 2)
 270                 *to++ = (value & 0xFF0000) >> 16;
 271         if (len > 1)
 272                 *to++ = (value & 0xFF00) >> 8;
 273         if (len > 0)
 274                 *to++ = (value & 0xFF);
 275 }
 276
 277 static inline int dccp_ndp_len(const int ndp)
 278 {
 279         return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
 280 }
 281
 282 int dccp_insert_option(struct sock *sk, struct sk_buff *skb,
 283                         const unsigned char option,
 284                         const void *value, const unsigned char len)
 285 {
 286         unsigned char *to;
 287
 288         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
 289                 return -1;
 290
 291         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
 292
 293         to    = skb_push(skb, len + 2);
 294         *to++ = option;
 295         *to++ = len + 2;
 296
 297         memcpy(to, value, len);
 298         return 0;
 299 }
 300
 301 EXPORT_SYMBOL_GPL(dccp_insert_option);
 302
 303 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
 304 {
 305         struct dccp_sock *dp = dccp_sk(sk);
 306         int ndp = dp->dccps_ndp_count;
 307
 308         if (dccp_non_data_packet(skb))
 309                 ++dp->dccps_ndp_count;
 310         else
 311                 dp->dccps_ndp_count = 0;
 312
 313         if (ndp > 0) {
 314                 unsigned char *ptr;
 315                 const int ndp_len = dccp_ndp_len(ndp);
 316                 const int len = ndp_len + 2;
 317
 318                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 319                         return -1;
 320
 321                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 322
 323                 ptr = skb_push(skb, len);
 324                 *ptr++ = DCCPO_NDP_COUNT;
 325                 *ptr++ = len;
 326                 dccp_encode_value_var(ndp, ptr, ndp_len);
 327         }
 328
 329         return 0;
 330 }
 331
 332 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
 333 {
 334         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
 335 }
 336
 337 int dccp_insert_option_elapsed_time(struct sock *sk, struct sk_buff *skb,
 338                                     u32 elapsed_time)
 339 {
 340         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 341         const int len = 2 + elapsed_time_len;
 342         unsigned char *to;
 343
 344         if (elapsed_time_len == 0)
 345                 return 0;
 346
 347         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 348                 return -1;
 349
 350         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 351
 352         to    = skb_push(skb, len);
 353         *to++ = DCCPO_ELAPSED_TIME;
 354         *to++ = len;
 355
 356         if (elapsed_time_len == 2) {
 357                 const __be16 var16 = htons((u16)elapsed_time);
 358                 memcpy(to, &var16, 2);
 359         } else {
 360                 const __be32 var32 = htonl(elapsed_time);
 361                 memcpy(to, &var32, 4);
 362         }
 363
 364         return 0;
 365 }
 366
 367 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
 368
 369 void dccp_timestamp(const struct sock *sk, struct timeval *tv)
 370 {
 371         const struct dccp_sock *dp = dccp_sk(sk);
 372
 373         do_gettimeofday(tv);
 374         tv->tv_sec  -= dp->dccps_epoch.tv_sec;
 375         tv->tv_usec -= dp->dccps_epoch.tv_usec;
 376
 377         while (tv->tv_usec < 0) {
 378                 tv->tv_sec--;
 379                 tv->tv_usec += USEC_PER_SEC;
 380         }
 381 }
 382
 383 EXPORT_SYMBOL_GPL(dccp_timestamp);
 384
 385 int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
 386 {
 387         struct timeval tv;
 388         __be32 now;
 389
 390         dccp_timestamp(sk, &tv);
 391         now = htonl(timeval_usecs(&tv) / 10);
 392         /* yes this will overflow but that is the point as we want a
 393          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
 394
 395         return dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 396 }
 397
 398 EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
 399
 400 static int dccp_insert_option_timestamp_echo(struct sock *sk,
 401                                              struct sk_buff *skb)
 402 {
 403         struct dccp_sock *dp = dccp_sk(sk);
 404         struct timeval now;
 405         __be32 tstamp_echo;
 406         u32 elapsed_time;
 407         int len, elapsed_time_len;
 408         unsigned char *to;
 409
 410         dccp_timestamp(sk, &now);
 411         elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
 412         elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 413         len = 6 + elapsed_time_len;
 414
 415         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 416                 return -1;
 417
 418         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 419
 420         to    = skb_push(skb, len);
 421         *to++ = DCCPO_TIMESTAMP_ECHO;
 422         *to++ = len;
 423
 424         tstamp_echo = htonl(dp->dccps_timestamp_echo);
 425         memcpy(to, &tstamp_echo, 4);
 426         to += 4;
 427
 428         if (elapsed_time_len == 2) {
 429                 const __be16 var16 = htons((u16)elapsed_time);
 430                 memcpy(to, &var16, 2);
 431         } else if (elapsed_time_len == 4) {
 432                 const __be32 var32 = htonl(elapsed_time);
 433                 memcpy(to, &var32, 4);
 434         }
 435
 436         dp->dccps_timestamp_echo = 0;
 437         dp->dccps_timestamp_time.tv_sec = 0;
 438         dp->dccps_timestamp_time.tv_usec = 0;
 439         return 0;
 440 }
 441
 442 static int dccp_insert_feat_opt(struct sk_buff *skb, u8 type, u8 feat,
 443                                 u8 *val, u8 len)
 444 {
 445         u8 *to;
 446
 447         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 3 > DCCP_MAX_OPT_LEN) {
 448                 DCCP_WARN("packet too small for feature %d option!\n", feat);
 449                 return -1;
 450         }
 451
 452         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 3;
 453
 454         to    = skb_push(skb, len + 3);
 455         *to++ = type;
 456         *to++ = len + 3;
 457         *to++ = feat;
 458
 459         if (len)
 460                 memcpy(to, val, len);
 461
 462         dccp_pr_debug("%s(%s (%d), ...), length %d\n",
 463                       dccp_feat_typename(type),
 464                       dccp_feat_name(feat), feat, len);
 465         return 0;
 466 }
 467
 468 static int dccp_insert_options_feat(struct sock *sk, struct sk_buff *skb)
 469 {
 470         struct dccp_sock *dp = dccp_sk(sk);
 471         struct dccp_minisock *dmsk = dccp_msk(sk);
 472         struct dccp_opt_pend *opt, *next;
 473         int change = 0;
 474
 475         /* confirm any options [NN opts] */
 476         list_for_each_entry_safe(opt, next, &dmsk->dccpms_conf, dccpop_node) {
 477                 dccp_insert_feat_opt(skb, opt->dccpop_type,
 478                                      opt->dccpop_feat, opt->dccpop_val,
 479                                      opt->dccpop_len);
 480                 /* fear empty confirms */
 481                 if (opt->dccpop_val)
 482                         kfree(opt->dccpop_val);
 483                 kfree(opt);
 484         }
 485         INIT_LIST_HEAD(&dmsk->dccpms_conf);
 486
 487         /* see which features we need to send */
 488         list_for_each_entry(opt, &dmsk->dccpms_pending, dccpop_node) {
 489                 /* see if we need to send any confirm */
 490                 if (opt->dccpop_sc) {
 491                         dccp_insert_feat_opt(skb, opt->dccpop_type + 1,
 492                                              opt->dccpop_feat,
 493                                              opt->dccpop_sc->dccpoc_val,
 494                                              opt->dccpop_sc->dccpoc_len);
 495
 496                         BUG_ON(!opt->dccpop_sc->dccpoc_val);
 497                         kfree(opt->dccpop_sc->dccpoc_val);
 498                         kfree(opt->dccpop_sc);
 499                         opt->dccpop_sc = NULL;
 500                 }
 501
 502                 /* any option not confirmed, re-send it */
 503                 if (!opt->dccpop_conf) {
 504                         dccp_insert_feat_opt(skb, opt->dccpop_type,
 505                                              opt->dccpop_feat, opt->dccpop_val,
 506                                              opt->dccpop_len);
 507                         change++;
 508                 }
 509         }
 510
 511         /* Retransmit timer.
 512          * If this is the master listening sock, we don't set a timer on it.  It
 513          * should be fine because if the dude doesn't receive our RESPONSE
 514          * [which will contain the CHANGE] he will send another REQUEST which
 515          * will "retrnasmit" the change.
 516          */
 517         if (change && dp->dccps_role != DCCP_ROLE_LISTEN) {
 518                 dccp_pr_debug("reset feat negotiation timer %p\n", sk);
 519
 520                 /* XXX don't reset the timer on re-transmissions.  I.e. reset it
 521                  * only when sending new stuff i guess.  Currently the timer
 522                  * never backs off because on re-transmission it just resets it!
 523                  */
 524                 inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
 525                                           inet_csk(sk)->icsk_rto, DCCP_RTO_MAX);
 526         }
 527
 528         return 0;
 529 }
 530
 531 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 532 {
 533         struct dccp_sock *dp = dccp_sk(sk);
 534         struct dccp_minisock *dmsk = dccp_msk(sk);
 535
 536         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 537
 538         if (dmsk->dccpms_send_ndp_count &&
 539             dccp_insert_option_ndp(sk, skb))
 540                 return -1;
 541
 542         if (!dccp_packet_without_ack(skb)) {
 543                 if (dmsk->dccpms_send_ack_vector &&
 544                     dccp_ackvec_pending(dp->dccps_hc_rx_ackvec) &&
 545                     dccp_insert_option_ackvec(sk, skb))
 546                         return -1;
 547
 548                 if (dp->dccps_timestamp_echo != 0 &&
 549                     dccp_insert_option_timestamp_echo(sk, skb))
 550                         return -1;
 551         }
 552
 553         if (dp->dccps_hc_rx_insert_options) {
 554                 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
 555                         return -1;
 556                 dp->dccps_hc_rx_insert_options = 0;
 557         }
 558
 559         /* Feature negotiation */
 560         /* Data packets can't do feat negotiation */
 561         if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA &&
 562             DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATAACK &&
 563             dccp_insert_options_feat(sk, skb))
 564                 return -1;
 565
 566         /* XXX: insert other options when appropriate */
 567
 568         if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
 569                 /* The length of all options has to be a multiple of 4 */
 570                 int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
 571
 572                 if (padding != 0) {
 573                         padding = 4 - padding;
 574                         memset(skb_push(skb, padding), 0, padding);
 575                         DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
 576                 }
 577         }
 578
 579         return 0;
 580 }