root/net/dccp/options.c

DEFINITIONS

1. dccp_decode_value_var
2. dccp_parse_options
3. dccp_encode_value_var
4. dccp_ndp_len
5. dccp_insert_option
6. dccp_insert_option_ndp
7. dccp_elapsed_time_len
8. dccp_insert_option_timestamp
9. dccp_insert_option_timestamp_echo
10. dccp_insert_option_ackvec
11. dccp_insert_option_mandatory
12. dccp_insert_fn_opt
13. dccp_insert_option_padding
14. dccp_insert_options
15. dccp_insert_options_rsk

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  net/dccp/options.c
   4  *
   5  *  An implementation of the DCCP protocol
   6  *  Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
   7  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
   8  *  Copyright (c) 2005 Ian McDonald <ian.mcdonald@jandi.co.nz>
   9  */
  10 #include <linux/dccp.h>
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <asm/unaligned.h>
  14 #include <linux/kernel.h>
  15 #include <linux/skbuff.h>
  16 
  17 #include "ackvec.h"
  18 #include "ccid.h"
  19 #include "dccp.h"
  20 #include "feat.h"
  21 
  22 u64 dccp_decode_value_var(const u8 *bf, const u8 len)
  23 {
  24         u64 value = 0;
  25 
  26         if (len >= DCCP_OPTVAL_MAXLEN)
  27                 value += ((u64)*bf++) << 40;
  28         if (len > 4)
  29                 value += ((u64)*bf++) << 32;
  30         if (len > 3)
  31                 value += ((u64)*bf++) << 24;
  32         if (len > 2)
  33                 value += ((u64)*bf++) << 16;
  34         if (len > 1)
  35                 value += ((u64)*bf++) << 8;
  36         if (len > 0)
  37                 value += *bf;
  38 
  39         return value;
  40 }
  41 
  42 /**
  43  * dccp_parse_options  -  Parse DCCP options present in @skb
  44  * @sk: client|server|listening dccp socket (when @dreq != NULL)
  45  * @dreq: request socket to use during connection setup, or NULL
  46  */
  47 int dccp_parse_options(struct sock *sk, struct dccp_request_sock *dreq,
  48                        struct sk_buff *skb)
  49 {
  50         struct dccp_sock *dp = dccp_sk(sk);
  51         const struct dccp_hdr *dh = dccp_hdr(skb);
  52         const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
  53         unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
  54         unsigned char *opt_ptr = options;
  55         const unsigned char *opt_end = (unsigned char *)dh +
  56                                         (dh->dccph_doff * 4);
  57         struct dccp_options_received *opt_recv = &dp->dccps_options_received;
  58         unsigned char opt, len;
  59         unsigned char *uninitialized_var(value);
  60         u32 elapsed_time;
  61         __be32 opt_val;
  62         int rc;
  63         int mandatory = 0;
  64 
  65         memset(opt_recv, 0, sizeof(*opt_recv));
  66 
  67         opt = len = 0;
  68         while (opt_ptr != opt_end) {
  69                 opt   = *opt_ptr++;
  70                 len   = 0;
  71                 value = NULL;
  72 
  73                 /* Check if this isn't a single byte option */
  74                 if (opt > DCCPO_MAX_RESERVED) {
  75                         if (opt_ptr == opt_end)
  76                                 goto out_nonsensical_length;
  77 
  78                         len = *opt_ptr++;
  79                         if (len < 2)
  80                                 goto out_nonsensical_length;
  81                         /*
  82                          * Remove the type and len fields, leaving
  83                          * just the value size
  84                          */
  85                         len     -= 2;
  86                         value   = opt_ptr;
  87                         opt_ptr += len;
  88 
  89                         if (opt_ptr > opt_end)
  90                                 goto out_nonsensical_length;
  91                 }
  92 
  93                 /*
  94                  * CCID-specific options are ignored during connection setup, as
  95                  * negotiation may still be in progress (see RFC 4340, 10.3).
  96                  * The same applies to Ack Vectors, as these depend on the CCID.
  97                  */
  98                 if (dreq != NULL && (opt >= DCCPO_MIN_RX_CCID_SPECIFIC ||
  99                     opt == DCCPO_ACK_VECTOR_0 || opt == DCCPO_ACK_VECTOR_1))
 100                         goto ignore_option;
 101 
 102                 switch (opt) {
 103                 case DCCPO_PADDING:
 104                         break;
 105                 case DCCPO_MANDATORY:
 106                         if (mandatory)
 107                                 goto out_invalid_option;
 108                         if (pkt_type != DCCP_PKT_DATA)
 109                                 mandatory = 1;
 110                         break;
 111                 case DCCPO_NDP_COUNT:
 112                         if (len > 6)
 113                                 goto out_invalid_option;
 114 
 115                         opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
 116                         dccp_pr_debug("%s opt: NDP count=%llu\n", dccp_role(sk),
 117                                       (unsigned long long)opt_recv->dccpor_ndp);
 118                         break;
 119                 case DCCPO_CHANGE_L ... DCCPO_CONFIRM_R:
 120                         if (pkt_type == DCCP_PKT_DATA)      /* RFC 4340, 6 */
 121                                 break;
 122                         if (len == 0)
 123                                 goto out_invalid_option;
 124                         rc = dccp_feat_parse_options(sk, dreq, mandatory, opt,
 125                                                     *value, value + 1, len - 1);
 126                         if (rc)
 127                                 goto out_featneg_failed;
 128                         break;
 129                 case DCCPO_TIMESTAMP:
 130                         if (len != 4)
 131                                 goto out_invalid_option;
 132                         /*
 133                          * RFC 4340 13.1: "The precise time corresponding to
 134                          * Timestamp Value zero is not specified". We use
 135                          * zero to indicate absence of a meaningful timestamp.
 136                          */
 137                         opt_val = get_unaligned((__be32 *)value);
 138                         if (unlikely(opt_val == 0)) {
 139                                 DCCP_WARN("Timestamp with zero value\n");
 140                                 break;
 141                         }
 142 
 143                         if (dreq != NULL) {
 144                                 dreq->dreq_timestamp_echo = ntohl(opt_val);
 145                                 dreq->dreq_timestamp_time = dccp_timestamp();
 146                         } else {
 147                                 opt_recv->dccpor_timestamp =
 148                                         dp->dccps_timestamp_echo = ntohl(opt_val);
 149                                 dp->dccps_timestamp_time = dccp_timestamp();
 150                         }
 151                         dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
 152                                       dccp_role(sk), ntohl(opt_val),
 153                                       (unsigned long long)
 154                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 155                         /* schedule an Ack in case this sender is quiescent */
 156                         inet_csk_schedule_ack(sk);
 157                         break;
 158                 case DCCPO_TIMESTAMP_ECHO:
 159                         if (len != 4 && len != 6 && len != 8)
 160                                 goto out_invalid_option;
 161 
 162                         opt_val = get_unaligned((__be32 *)value);
 163                         opt_recv->dccpor_timestamp_echo = ntohl(opt_val);
 164 
 165                         dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, "
 166                                       "ackno=%llu", dccp_role(sk),
 167                                       opt_recv->dccpor_timestamp_echo,
 168                                       len + 2,
 169                                       (unsigned long long)
 170                                       DCCP_SKB_CB(skb)->dccpd_ack_seq);
 171 
 172                         value += 4;
 173 
 174                         if (len == 4) {         /* no elapsed time included */
 175                                 dccp_pr_debug_cat("\n");
 176                                 break;
 177                         }
 178 
 179                         if (len == 6) {         /* 2-byte elapsed time */
 180                                 __be16 opt_val2 = get_unaligned((__be16 *)value);
 181                                 elapsed_time = ntohs(opt_val2);
 182                         } else {                /* 4-byte elapsed time */
 183                                 opt_val = get_unaligned((__be32 *)value);
 184                                 elapsed_time = ntohl(opt_val);
 185                         }
 186 
 187                         dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time);
 188 
 189                         /* Give precedence to the biggest ELAPSED_TIME */
 190                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 191                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 192                         break;
 193                 case DCCPO_ELAPSED_TIME:
 194                         if (dccp_packet_without_ack(skb))   /* RFC 4340, 13.2 */
 195                                 break;
 196 
 197                         if (len == 2) {
 198                                 __be16 opt_val2 = get_unaligned((__be16 *)value);
 199                                 elapsed_time = ntohs(opt_val2);
 200                         } else if (len == 4) {
 201                                 opt_val = get_unaligned((__be32 *)value);
 202                                 elapsed_time = ntohl(opt_val);
 203                         } else {
 204                                 goto out_invalid_option;
 205                         }
 206 
 207                         if (elapsed_time > opt_recv->dccpor_elapsed_time)
 208                                 opt_recv->dccpor_elapsed_time = elapsed_time;
 209 
 210                         dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n",
 211                                       dccp_role(sk), elapsed_time);
 212                         break;
 213                 case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC:
 214                         if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
 215                                                      pkt_type, opt, value, len))
 216                                 goto out_invalid_option;
 217                         break;
 218                 case DCCPO_ACK_VECTOR_0:
 219                 case DCCPO_ACK_VECTOR_1:
 220                         if (dccp_packet_without_ack(skb))   /* RFC 4340, 11.4 */
 221                                 break;
 222                         /*
 223                          * Ack vectors are processed by the TX CCID if it is
 224                          * interested. The RX CCID need not parse Ack Vectors,
 225                          * since it is only interested in clearing old state.
 226                          */
 227                         /* fall through */
 228                 case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC:
 229                         if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
 230                                                      pkt_type, opt, value, len))
 231                                 goto out_invalid_option;
 232                         break;
 233                 default:
 234                         DCCP_CRIT("DCCP(%p): option %d(len=%d) not "
 235                                   "implemented, ignoring", sk, opt, len);
 236                         break;
 237                 }
 238 ignore_option:
 239                 if (opt != DCCPO_MANDATORY)
 240                         mandatory = 0;
 241         }
 242 
 243         /* mandatory was the last byte in option list -> reset connection */
 244         if (mandatory)
 245                 goto out_invalid_option;
 246 
 247 out_nonsensical_length:
 248         /* RFC 4340, 5.8: ignore option and all remaining option space */
 249         return 0;
 250 
 251 out_invalid_option:
 252         DCCP_INC_STATS(DCCP_MIB_INVALIDOPT);
 253         rc = DCCP_RESET_CODE_OPTION_ERROR;
 254 out_featneg_failed:
 255         DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc);
 256         DCCP_SKB_CB(skb)->dccpd_reset_code = rc;
 257         DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt;
 258         DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0;
 259         DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0;
 260         return -1;
 261 }
 262 
 263 EXPORT_SYMBOL_GPL(dccp_parse_options);
 264 
 265 void dccp_encode_value_var(const u64 value, u8 *to, const u8 len)
 266 {
 267         if (len >= DCCP_OPTVAL_MAXLEN)
 268                 *to++ = (value & 0xFF0000000000ull) >> 40;
 269         if (len > 4)
 270                 *to++ = (value & 0xFF00000000ull) >> 32;
 271         if (len > 3)
 272                 *to++ = (value & 0xFF000000) >> 24;
 273         if (len > 2)
 274                 *to++ = (value & 0xFF0000) >> 16;
 275         if (len > 1)
 276                 *to++ = (value & 0xFF00) >> 8;
 277         if (len > 0)
 278                 *to++ = (value & 0xFF);
 279 }
 280 
 281 static inline u8 dccp_ndp_len(const u64 ndp)
 282 {
 283         if (likely(ndp <= 0xFF))
 284                 return 1;
 285         return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6);
 286 }
 287 
 288 int dccp_insert_option(struct sk_buff *skb, const unsigned char option,
 289                        const void *value, const unsigned char len)
 290 {
 291         unsigned char *to;
 292 
 293         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN)
 294                 return -1;
 295 
 296         DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
 297 
 298         to    = skb_push(skb, len + 2);
 299         *to++ = option;
 300         *to++ = len + 2;
 301 
 302         memcpy(to, value, len);
 303         return 0;
 304 }
 305 
 306 EXPORT_SYMBOL_GPL(dccp_insert_option);
 307 
 308 static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
 309 {
 310         struct dccp_sock *dp = dccp_sk(sk);
 311         u64 ndp = dp->dccps_ndp_count;
 312 
 313         if (dccp_non_data_packet(skb))
 314                 ++dp->dccps_ndp_count;
 315         else
 316                 dp->dccps_ndp_count = 0;
 317 
 318         if (ndp > 0) {
 319                 unsigned char *ptr;
 320                 const int ndp_len = dccp_ndp_len(ndp);
 321                 const int len = ndp_len + 2;
 322 
 323                 if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 324                         return -1;
 325 
 326                 DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 327 
 328                 ptr = skb_push(skb, len);
 329                 *ptr++ = DCCPO_NDP_COUNT;
 330                 *ptr++ = len;
 331                 dccp_encode_value_var(ndp, ptr, ndp_len);
 332         }
 333 
 334         return 0;
 335 }
 336 
 337 static inline int dccp_elapsed_time_len(const u32 elapsed_time)
 338 {
 339         return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
 340 }
 341 
 342 static int dccp_insert_option_timestamp(struct sk_buff *skb)
 343 {
 344         __be32 now = htonl(dccp_timestamp());
 345         /* yes this will overflow but that is the point as we want a
 346          * 10 usec 32 bit timer which mean it wraps every 11.9 hours */
 347 
 348         return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now));
 349 }
 350 
 351 static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp,
 352                                              struct dccp_request_sock *dreq,
 353                                              struct sk_buff *skb)
 354 {
 355         __be32 tstamp_echo;
 356         unsigned char *to;
 357         u32 elapsed_time, elapsed_time_len, len;
 358 
 359         if (dreq != NULL) {
 360                 elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time;
 361                 tstamp_echo  = htonl(dreq->dreq_timestamp_echo);
 362                 dreq->dreq_timestamp_echo = 0;
 363         } else {
 364                 elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time;
 365                 tstamp_echo  = htonl(dp->dccps_timestamp_echo);
 366                 dp->dccps_timestamp_echo = 0;
 367         }
 368 
 369         elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
 370         len = 6 + elapsed_time_len;
 371 
 372         if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
 373                 return -1;
 374 
 375         DCCP_SKB_CB(skb)->dccpd_opt_len += len;
 376 
 377         to    = skb_push(skb, len);
 378         *to++ = DCCPO_TIMESTAMP_ECHO;
 379         *to++ = len;
 380 
 381         memcpy(to, &tstamp_echo, 4);
 382         to += 4;
 383 
 384         if (elapsed_time_len == 2) {
 385                 const __be16 var16 = htons((u16)elapsed_time);
 386                 memcpy(to, &var16, 2);
 387         } else if (elapsed_time_len == 4) {
 388                 const __be32 var32 = htonl(elapsed_time);
 389                 memcpy(to, &var32, 4);
 390         }
 391 
 392         return 0;
 393 }
 394 
 395 static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb)
 396 {
 397         struct dccp_sock *dp = dccp_sk(sk);
 398         struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec;
 399         struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
 400         const u16 buflen = dccp_ackvec_buflen(av);
 401         /* Figure out how many options do we need to represent the ackvec */
 402         const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN);
 403         u16 len = buflen + 2 * nr_opts;
 404         u8 i, nonce = 0;
 405         const unsigned char *tail, *from;
 406         unsigned char *to;
 407 
 408         if (dcb->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
 409                 DCCP_WARN("Lacking space for %u bytes on %s packet\n", len,
 410                           dccp_packet_name(dcb->dccpd_type));
 411                 return -1;
 412         }
 413         /*
 414          * Since Ack Vectors are variable-length, we can not always predict
 415          * their size. To catch exception cases where the space is running out
 416          * on the skb, a separate Sync is scheduled to carry the Ack Vector.
 417          */
 418         if (len > DCCPAV_MIN_OPTLEN &&
 419             len + dcb->dccpd_opt_len + skb->len > dp->dccps_mss_cache) {
 420                 DCCP_WARN("No space left for Ack Vector (%u) on skb (%u+%u), "
 421                           "MPS=%u ==> reduce payload size?\n", len, skb->len,
 422                           dcb->dccpd_opt_len, dp->dccps_mss_cache);
 423                 dp->dccps_sync_scheduled = 1;
 424                 return 0;
 425         }
 426         dcb->dccpd_opt_len += len;
 427 
 428         to   = skb_push(skb, len);
 429         len  = buflen;
 430         from = av->av_buf + av->av_buf_head;
 431         tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN;
 432 
 433         for (i = 0; i < nr_opts; ++i) {
 434                 int copylen = len;
 435 
 436                 if (len > DCCP_SINGLE_OPT_MAXLEN)
 437                         copylen = DCCP_SINGLE_OPT_MAXLEN;
 438 
 439                 /*
 440                  * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via
 441                  * its type; ack_nonce is the sum of all individual buf_nonce's.
 442                  */
 443                 nonce ^= av->av_buf_nonce[i];
 444 
 445                 *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i];
 446                 *to++ = copylen + 2;
 447 
 448                 /* Check if buf_head wraps */
 449                 if (from + copylen > tail) {
 450                         const u16 tailsize = tail - from;
 451 
 452                         memcpy(to, from, tailsize);
 453                         to      += tailsize;
 454                         len     -= tailsize;
 455                         copylen -= tailsize;
 456                         from    = av->av_buf;
 457                 }
 458 
 459                 memcpy(to, from, copylen);
 460                 from += copylen;
 461                 to   += copylen;
 462                 len  -= copylen;
 463         }
 464         /*
 465          * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340.
 466          */
 467         if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce))
 468                 return -ENOBUFS;
 469         return 0;
 470 }
 471 
 472 /**
 473  * dccp_insert_option_mandatory  -  Mandatory option (5.8.2)
 474  * Note that since we are using skb_push, this function needs to be called
 475  * _after_ inserting the option it is supposed to influence (stack order).
 476  */
 477 int dccp_insert_option_mandatory(struct sk_buff *skb)
 478 {
 479         if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN)
 480                 return -1;
 481 
 482         DCCP_SKB_CB(skb)->dccpd_opt_len++;
 483         *(u8 *)skb_push(skb, 1) = DCCPO_MANDATORY;
 484         return 0;
 485 }
 486 
 487 /**
 488  * dccp_insert_fn_opt  -  Insert single Feature-Negotiation option into @skb
 489  * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R
 490  * @feat: one out of %dccp_feature_numbers
 491  * @val: NN value or SP array (preferred element first) to copy
 492  * @len: true length of @val in bytes (excluding first element repetition)
 493  * @repeat_first: whether to copy the first element of @val twice
 494  *
 495  * The last argument is used to construct Confirm options, where the preferred
 496  * value and the preference list appear separately (RFC 4340, 6.3.1). Preference
 497  * lists are kept such that the preferred entry is always first, so we only need
 498  * to copy twice, and avoid the overhead of cloning into a bigger array.
 499  */
 500 int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat,
 501                        u8 *val, u8 len, bool repeat_first)
 502 {
 503         u8 tot_len, *to;
 504 
 505         /* take the `Feature' field and possible repetition into account */
 506         if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) {
 507                 DCCP_WARN("length %u for feature %u too large\n", len, feat);
 508                 return -1;
 509         }
 510 
 511         if (unlikely(val == NULL || len == 0))
 512                 len = repeat_first = false;
 513         tot_len = 3 + repeat_first + len;
 514 
 515         if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) {
 516                 DCCP_WARN("packet too small for feature %d option!\n", feat);
 517                 return -1;
 518         }
 519         DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len;
 520 
 521         to    = skb_push(skb, tot_len);
 522         *to++ = type;
 523         *to++ = tot_len;
 524         *to++ = feat;
 525 
 526         if (repeat_first)
 527                 *to++ = *val;
 528         if (len)
 529                 memcpy(to, val, len);
 530         return 0;
 531 }
 532 
 533 /* The length of all options needs to be a multiple of 4 (5.8) */
 534 static void dccp_insert_option_padding(struct sk_buff *skb)
 535 {
 536         int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
 537 
 538         if (padding != 0) {
 539                 padding = 4 - padding;
 540                 memset(skb_push(skb, padding), 0, padding);
 541                 DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
 542         }
 543 }
 544 
 545 int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
 546 {
 547         struct dccp_sock *dp = dccp_sk(sk);
 548 
 549         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 550 
 551         if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb))
 552                 return -1;
 553 
 554         if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) {
 555 
 556                 /* Feature Negotiation */
 557                 if (dccp_feat_insert_opts(dp, NULL, skb))
 558                         return -1;
 559 
 560                 if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) {
 561                         /*
 562                          * Obtain RTT sample from Request/Response exchange.
 563                          * This is currently used for TFRC initialisation.
 564                          */
 565                         if (dccp_insert_option_timestamp(skb))
 566                                 return -1;
 567 
 568                 } else if (dccp_ackvec_pending(sk) &&
 569                            dccp_insert_option_ackvec(sk, skb)) {
 570                                 return -1;
 571                 }
 572         }
 573 
 574         if (dp->dccps_hc_rx_insert_options) {
 575                 if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb))
 576                         return -1;
 577                 dp->dccps_hc_rx_insert_options = 0;
 578         }
 579 
 580         if (dp->dccps_timestamp_echo != 0 &&
 581             dccp_insert_option_timestamp_echo(dp, NULL, skb))
 582                 return -1;
 583 
 584         dccp_insert_option_padding(skb);
 585         return 0;
 586 }
 587 
 588 int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb)
 589 {
 590         DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
 591 
 592         if (dccp_feat_insert_opts(NULL, dreq, skb))
 593                 return -1;
 594 
 595         /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */
 596         if (dccp_insert_option_timestamp(skb))
 597                 return -1;
 598 
 599         if (dreq->dreq_timestamp_echo != 0 &&
 600             dccp_insert_option_timestamp_echo(NULL, dreq, skb))
 601                 return -1;
 602 
 603         dccp_insert_option_padding(skb);
 604         return 0;
 605 }