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 <asm/unaligned.h>
  18 #include <linux/kernel.h>
  19 #include <linux/skbuff.h>
  20
  21 #include "ackvec.h"
  22 #include "ccid.h"
  23 #include "dccp.h"
  24 #include "feat.h"
  25
  26 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
  27 {
  28         u64 value = 0;
  29
  30         if (len >= DCCP_OPTVAL_MAXLEN)
  31                 value += ((u64)*bf++) << 40;
  32         if (len > 4)
  33                 value += ((u64)*bf++) << 32;
  34         if (len > 3)
  35                 value += ((u64)*bf++) << 24;
  36         if (len > 2)
  37                 value += ((u64)*bf++) << 16;
  38         if (len > 1)
  39                 value += ((u64)*bf++) << 8;
  40         if (len > 0)
  41                 value += *bf;
  42
  43         return value;
  44 }
  45
  46 /**
  47  * dccp_parse_options  -  Parse DCCP options present in @skb
  48  * @sk: client|server|listening dccp socket (when @dreq != NULL)
  49  * @dreq: request socket to use during connection setup, or NULL
  50  */
  51 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
  52                        struct sk_buff *skb)
  53 {
  54         struct dccp_sock *dp = dccp_sk(sk);
  55         const struct dccp_hdr *dh = dccp_hdr(skb);
  56         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
  57         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
  58         unsigned char *opt_ptr = options;
  59         const unsigned char *opt_end = (unsigned char *)dh +
  60                                         (dh->dccph_doff * 4);
  61         struct dccp_options_received *opt_recv = &dp->dccps_options_received;
  62         unsigned char opt, len;
  63         unsigned char *uninitialized_var(value);
  64         u32 elapsed_time;
  65         __be32 opt_val;
  66         int rc;
  67         int mandatory = 0;
  68
  69         memset(opt_recv, 0, sizeof(*opt_recv));
  70
  71         opt = len = 0;
  72         while (opt_ptr != opt_end) {
  73                 opt   = *opt_ptr++;
  74                 len   = 0;
  75                 value = NULL;
  76
  77                 /* Check if this isn't a single byte option */
  78                 if (opt > DCCPO_MAX_RESERVED) {
  79                         if (opt_ptr == opt_end)
  80                                 goto out_nonsensical_length;
  81
  82                         len = *opt_ptr++;
  83                         if (len < 2)
  84                                 goto out_nonsensical_length;
  85                         /*
  86                          * Remove the type and len fields, leaving
  87                          * just the value size
  88                          */
  89                         len     -= 2;
  90                         value   = opt_ptr;
  91                         opt_ptr += len;
  92
  93                         if (opt_ptr > opt_end)
  94                                 goto out_nonsensical_length;
  95                 }
  96
  97                 /*
  98                  * CCID-specific options are ignored during connection setup, as
  99                  * negotiation may still be in progress (see RFC 4340, 10.3).
 100                  * The same applies to Ack Vectors, as these depend on the CCID.
 101                  */
 102                 if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC ||
 103                     opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
 104                         goto ignore_option;
 105
 106                 switch (opt) {
 107                 case DCCPO_PADDING:
 108                         break;
 109                 case DCCPO_MANDATORY:
 110                         if (mandatory)
 111                                 goto out_invalid_option;
 112                         if (pkt_type != DCCP_PKT_DATA)
 113                                 mandatory = 1;
 114                         break;
 115                 case DCCPO_NDP_COUNT:
 116                         if (len > 6)
 117                                 goto out_invalid_option;
 118
 119                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
 120                         dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
 121                                       (unsigned long long)opt_recv->dccpor_ndp);
 122                         break;
 123                 case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
 124                         if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */
 125                                 break;
 126                         rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
 127                                                     *value, value + 1, len - 1);
 128                         if (rc)
 129                                 goto out_featneg_failed;
 130                         break;
 131                 case DCCPO_ACK_VECTOR_0:
 132                 case DCCPO_ACK_VECTOR_1:
 133                         if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
 134                                 break;
 135                         dccp_pr_debug("%s Ack Vector (len=%u)\n", dccp_role(sk),
 136                                       len);
 137                         break;
 138                 case DCCPO_TIMESTAMP:
 139                         if (len != 4)
 140                                 goto out_invalid_option;
 141                         /*
 142                          * RFC 4340 13.1: "The precise time corresponding to
 143                          * Timestamp Value zero is not specified". We use
 144                          * zero to indicate absence of a meaningful timestamp.
 145                          */
 146                         opt_val = get_unaligned((__be32 *)value);
 147                         if (unlikely(opt_val == 0)) {
 148                                 DCCP_WARN("Timestamp with zero value\n");
 149                                 break;
 150                         }
 151
 152                         if (dreq != NULL) {
 153                                 dreq->dreq_timestamp_echo = ntohl(opt_val);
 154                                 dreq->dreq_timestamp_time = dccp_timestamp();
 155                         } else {
 156                                 opt_recv->dccpor_timestamp =
 157                                         dp->dccps_timestamp_echo = ntohl(opt_val);
 158                                 dp->dccps_timestamp_time = dccp_timestamp();
 159                         }
 160                         dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
 161                                       dccp_role(sk), ntohl(opt_val),
 162                                       (unsigned long long)
 163                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 164                         /* schedule an Ack in case this sender is quiescent */
 165                         inet_csk_schedule_ack(sk);
 166                         break;
 167                 case DCCPO_TIMESTAMP_ECHO:
 168                         if (len != 4 && len != 6 && len != 8)
 169                                 goto out_invalid_option;
 170
 171                         opt_val = get_unaligned((__be32 *)value);
 172                         opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
 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                         value += 4;
 182
 183                         if (len == 4) {         /* no elapsed time included */
 184                                 dccp_pr_debug_cat("\n");
 185                                 break;
 186                         }
 187
 188                         if (len == 6) {         /* 2-byte elapsed time */
 189                                 __be16 opt_val2 = get_unaligned((__be16 *)value);
 190                                 elapsed_time = ntohs(opt_val2);
 191                         } else {                /* 4-byte elapsed time */
 192                                 opt_val = get_unaligned((__be32 *)value);
 193                                 elapsed_time = ntohl(opt_val);
 194                         }
 195
 196                         dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
 197
 198                         /* Give precedence to the biggest ELAPSED_TIME */
 199                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 200                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 201                         break;
 202                 case DCCPO_ELAPSED_TIME:
 203                         if (dccp_packet_without_ack(skb))   /* RFC 4340, 13.2 */
 204                                 break;
 205
 206                         if (len == 2) {
 207                                 __be16 opt_val2 = get_unaligned((__be16 *)value);
 208                                 elapsed_time = ntohs(opt_val2);
 209                         } else if (len == 4) {
 210                                 opt_val = get_unaligned((__be32 *)value);
 211                                 elapsed_time = ntohl(opt_val);
 212                         } else {
 213                                 goto out_invalid_option;
 214                         }
 215
 216                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 217                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 218
 219                         dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
 220                                       dccp_role(sk), elapsed_time);
 221                         break;
 222                 case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC:
 223                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
 224                                                      pkt_type, opt, value, len))
 225                                 goto out_invalid_option;
 226                         break;
 227                 case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
 228                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
 229                                                      pkt_type, opt, value, len))
 230                                 goto out_invalid_option;
 231                         break;
 232                 default:
 233                         DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
 234                                   "implemented, ignoring", sk, opt, len);
 235                         break;
 236                 }
 237 ignore_option:
 238                 if (opt != DCCPO_MANDATORY)
 239                         mandatory = 0;
 240         }
 241
 242         /* mandatory was the last byte in option list -> reset connection */
 243         if (mandatory)
 244                 goto out_invalid_option;
 245
 246 out_nonsensical_length:
 247         /* RFC 4340, 5.8: ignore option and all remaining option space */
 248         return 0;
 249
 250 out_invalid_option:
 251         DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
 252         rc = DCCP_RESET_CODE_OPTION_ERROR;
 253 out_featneg_failed:
 254         DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
 255         DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
 256         DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
 257         DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
 258         DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
 259         return -1;
 260 }
 261
 262 EXPORT_SYMBOL_GPL(dccp_parse_options);
 263
 264 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
 265 {
 266         if (len >= DCCP_OPTVAL_MAXLEN)
 267                 *to++ = (value & 0xFF0000000000ull) >> 40;
 268         if (len > 4)
 269                 *to++ = (value & 0xFF00000000ull) >> 32;
 270         if (len > 3)
 271                 *to++ = (value & 0xFF000000) >> 24;
 272         if (len > 2)
 273                 *to++ = (value & 0xFF0000) >> 16;
 274         if (len > 1)
 275                 *to++ = (value & 0xFF00) >> 8;
 276         if (len > 0)
 277                 *to++ = (value & 0xFF);
 278 }
 279
 280 static inline u8 dccp_ndp_len(const u64 ndp)
 281 {
 282         if (likely(ndp <= 0xFF))
 283                 return 1;
 284         return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
 285 }
 286
 287 int dccp_insert_option(struct sk_buff *skb, const unsigned char option,
 288                        const void *value, const unsigned char len)
 289 {
 290         unsigned char *to;
 291
 292         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
 293                 return -1;
 294
 295         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
 296
 297         to    = skb_push(skb, len + 2);
 298         *to++ = option;
 299         *to++ = len + 2;
 300
 301         memcpy(to, value, len);
 302         return 0;
 303 }
 304
 305 EXPORT_SYMBOL_GPL(dccp_insert_option);
 306
 307 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
 308 {
 309         struct dccp_sock *dp = dccp_sk(sk);
 310         u64 ndp = dp->dccps_ndp_count;
 311
 312         if (dccp_non_data_packet(skb))
 313                 ++dp->dccps_ndp_count;
 314         else
 315                 dp->dccps_ndp_count = 0;
 316
 317         if (ndp > 0) {
 318                 unsigned char *ptr;
 319                 const int ndp_len = dccp_ndp_len(ndp);
 320                 const int len = ndp_len + 2;
 321
 322                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 323                         return -1;
 324
 325                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 326
 327                 ptr = skb_push(skb, len);
 328                 *ptr++ = DCCPO_NDP_COUNT;
 329                 *ptr++ = len;
 330                 dccp_encode_value_var(ndp, ptr, ndp_len);
 331         }
 332
 333         return 0;
 334 }
 335
 336 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
 337 {
 338         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
 339 }
 340
 341 /* FIXME: This function is currently not used anywhere */
 342 int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time)
 343 {
 344         const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 345         const int len = 2 + elapsed_time_len;
 346         unsigned char *to;
 347
 348         if (elapsed_time_len == 0)
 349                 return 0;
 350
 351         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 352                 return -1;
 353
 354         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 355
 356         to    = skb_push(skb, len);
 357         *to++ = DCCPO_ELAPSED_TIME;
 358         *to++ = len;
 359
 360         if (elapsed_time_len == 2) {
 361                 const __be16 var16 = htons((u16)elapsed_time);
 362                 memcpy(to, &var16, 2);
 363         } else {
 364                 const __be32 var32 = htonl(elapsed_time);
 365                 memcpy(to, &var32, 4);
 366         }
 367
 368         return 0;
 369 }
 370
 371 EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
 372
 373 static int dccp_insert_option_timestamp(struct sk_buff *skb)
 374 {
 375         __be32 now = htonl(dccp_timestamp());
 376         /* yes this will overflow but that is the point as we want a
 377          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
 378
 379         return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 380 }
 381
 382 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
 383                                              struct dccp_request_sock *dreq,
 384                                              struct sk_buff *skb)
 385 {
 386         __be32 tstamp_echo;
 387         unsigned char *to;
 388         u32 elapsed_time, elapsed_time_len, len;
 389
 390         if (dreq != NULL) {
 391                 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
 392                 tstamp_echo  = htonl(dreq->dreq_timestamp_echo);
 393                 dreq->dreq_timestamp_echo = 0;
 394         } else {
 395                 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
 396                 tstamp_echo  = htonl(dp->dccps_timestamp_echo);
 397                 dp->dccps_timestamp_echo = 0;
 398         }
 399
 400         elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 401         len = 6 + elapsed_time_len;
 402
 403         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 404                 return -1;
 405
 406         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 407
 408         to    = skb_push(skb, len);
 409         *to++ = DCCPO_TIMESTAMP_ECHO;
 410         *to++ = len;
 411
 412         memcpy(to, &tstamp_echo, 4);
 413         to += 4;
 414
 415         if (elapsed_time_len == 2) {
 416                 const __be16 var16 = htons((u16)elapsed_time);
 417                 memcpy(to, &var16, 2);
 418         } else if (elapsed_time_len == 4) {
 419                 const __be32 var32 = htonl(elapsed_time);
 420                 memcpy(to, &var32, 4);
 421         }
 422
 423         return 0;
 424 }
 425
 426 static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
 427 {
 428         struct dccp_sock *dp = dccp_sk(sk);
 429         struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
 430         const u16 buflen = dccp_ackvec_buflen(av);
 431         /* Figure out how many options do we need to represent the ackvec */
 432         const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN);
 433         u16 len = buflen + 2 * nr_opts;
 434         u8 i, nonce = 0;
 435         const unsigned char *tail, *from;
 436         unsigned char *to;
 437
 438         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 439                 return -1;
 440
 441         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 442
 443         to   = skb_push(skb, len);
 444         len  = buflen;
 445         from = av->av_buf + av->av_buf_head;
 446         tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
 447
 448         for (i = 0; i < nr_opts; ++i) {
 449                 int copylen = len;
 450
 451                 if (len > DCCP_SINGLE_OPT_MAXLEN)
 452                         copylen = DCCP_SINGLE_OPT_MAXLEN;
 453
 454                 /*
 455                  * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via
 456                  * its type; ack_nonce is the sum of all individual buf_nonce's.
 457                  */
 458                 nonce ^= av->av_buf_nonce[i];
 459
 460                 *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i];
 461                 *to++ = copylen + 2;
 462
 463                 /* Check if buf_head wraps */
 464                 if (from + copylen > tail) {
 465                         const u16 tailsize = tail - from;
 466
 467                         memcpy(to, from, tailsize);
 468                         to      += tailsize;
 469                         len     -= tailsize;
 470                         copylen -= tailsize;
 471                         from    = av->av_buf;
 472                 }
 473
 474                 memcpy(to, from, copylen);
 475                 from += copylen;
 476                 to   += copylen;
 477                 len  -= copylen;
 478         }
 479         /*
 480          * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.
 481          */
 482         if (dccp_ackvec_update_records(av, DCCP_SKB_CB(skb)->dccpd_seq, nonce))
 483                 return -ENOBUFS;
 484         return 0;
 485 }
 486
 487 /**
 488  * dccp_insert_option_mandatory  -  Mandatory option (5.8.2)
 489  * Note that since we are using skb_push, this function needs to be called
 490  * _after_ inserting the option it is supposed to influence (stack order).
 491  */
 492 int dccp_insert_option_mandatory(struct sk_buff *skb)
 493 {
 494         if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
 495                 return -1;
 496
 497         DCCP_SKB_CB(skb)->dccpd_opt_len++;
 498         *skb_push(skb, 1) = DCCPO_MANDATORY;
 499         return 0;
 500 }
 501
 502 /**
 503  * dccp_insert_fn_opt  -  Insert single Feature-Negotiation option into @skb
 504  * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
 505  * @feat: one out of %dccp_feature_numbers
 506  * @val: NN value or SP array (preferred element first) to copy
 507  * @len: true length of @val in bytes (excluding first element repetition)
 508  * @repeat_first: whether to copy the first element of @val twice
 509  * The last argument is used to construct Confirm options, where the preferred
 510  * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
 511  * lists are kept such that the preferred entry is always first, so we only need
 512  * to copy twice, and avoid the overhead of cloning into a bigger array.
 513  */
 514 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
 515                        u8 *val, u8 len, bool repeat_first)
 516 {
 517         u8 tot_len, *to;
 518
 519         /* take the `Feature' field and possible repetition into account */
 520         if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
 521                 DCCP_WARN("length %u for feature %u too large\n", len, feat);
 522                 return -1;
 523         }
 524
 525         if (unlikely(val == NULL || len == 0))
 526                 len = repeat_first = 0;
 527         tot_len = 3 + repeat_first + len;
 528
 529         if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
 530                 DCCP_WARN("packet too small for feature %d option!\n", feat);
 531                 return -1;
 532         }
 533         DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
 534
 535         to    = skb_push(skb, tot_len);
 536         *to++ = type;
 537         *to++ = tot_len;
 538         *to++ = feat;
 539
 540         if (repeat_first)
 541                 *to++ = *val;
 542         if (len)
 543                 memcpy(to, val, len);
 544         return 0;
 545 }
 546
 547 /* The length of all options needs to be a multiple of 4 (5.8) */
 548 static void dccp_insert_option_padding(struct sk_buff *skb)
 549 {
 550         int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
 551
 552         if (padding != 0) {
 553                 padding = 4 - padding;
 554                 memset(skb_push(skb, padding), 0, padding);
 555                 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
 556         }
 557 }
 558
 559 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 560 {
 561         struct dccp_sock *dp = dccp_sk(sk);
 562
 563         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 564
 565         if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
 566                 return -1;
 567
 568         if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
 569
 570                 /* Feature Negotiation */
 571                 if (dccp_feat_insert_opts(dp, NULL, skb))
 572                         return -1;
 573
 574                 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
 575                         /*
 576                          * Obtain RTT sample from Request/Response exchange.
 577                          * This is currently used for TFRC initialisation.
 578                          */
 579                         if (dccp_insert_option_timestamp(skb))
 580                                 return -1;
 581
 582                 } else if (dccp_ackvec_pending(sk) &&
 583                            dccp_insert_option_ackvec(sk, skb)) {
 584                                 return -1;
 585                 }
 586         }
 587
 588         if (dp->dccps_hc_rx_insert_options) {
 589                 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
 590                         return -1;
 591                 dp->dccps_hc_rx_insert_options = 0;
 592         }
 593
 594         if (dp->dccps_timestamp_echo != 0 &&
 595             dccp_insert_option_timestamp_echo(dp, NULL, skb))
 596                 return -1;
 597
 598         dccp_insert_option_padding(skb);
 599         return 0;
 600 }
 601
 602 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
 603 {
 604         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 605
 606         if (dccp_feat_insert_opts(NULL, dreq, skb))
 607                 return -1;
 608
 609         /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */
 610         if (dccp_insert_option_timestamp(skb))
 611                 return -1;
 612
 613         if (dreq->dreq_timestamp_echo != 0 &&
 614             dccp_insert_option_timestamp_echo(NULL, dreq, skb))
 615                 return -1;
 616
 617         dccp_insert_option_padding(skb);
 618         return 0;
 619 }