| 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 | if (len == 0) |
| 127 | goto out_invalid_option; |
| 128 | rc = dccp_feat_parse_options(sk, dreq, mandatory, opt, |
| 129 | *value, value + 1, len - 1); |
| 130 | if (rc) |
| 131 | goto out_featneg_failed; |
| 132 | break; |
| 133 | case DCCPO_TIMESTAMP: |
| 134 | if (len != 4) |
| 135 | goto out_invalid_option; |
| 136 | /* |
| 137 | * RFC 4340 13.1: "The precise time corresponding to |
| 138 | * Timestamp Value zero is not specified". We use |
| 139 | * zero to indicate absence of a meaningful timestamp. |
| 140 | */ |
| 141 | opt_val = get_unaligned((__be32 *)value); |
| 142 | if (unlikely(opt_val == 0)) { |
| 143 | DCCP_WARN("Timestamp with zero value\n"); |
| 144 | break; |
| 145 | } |
| 146 | |
| 147 | if (dreq != NULL) { |
| 148 | dreq->dreq_timestamp_echo = ntohl(opt_val); |
| 149 | dreq->dreq_timestamp_time = dccp_timestamp(); |
| 150 | } else { |
| 151 | opt_recv->dccpor_timestamp = |
| 152 | dp->dccps_timestamp_echo = ntohl(opt_val); |
| 153 | dp->dccps_timestamp_time = dccp_timestamp(); |
| 154 | } |
| 155 | dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n", |
| 156 | dccp_role(sk), ntohl(opt_val), |
| 157 | (unsigned long long) |
| 158 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
| 159 | /* schedule an Ack in case this sender is quiescent */ |
| 160 | inet_csk_schedule_ack(sk); |
| 161 | break; |
| 162 | case DCCPO_TIMESTAMP_ECHO: |
| 163 | if (len != 4 && len != 6 && len != 8) |
| 164 | goto out_invalid_option; |
| 165 | |
| 166 | opt_val = get_unaligned((__be32 *)value); |
| 167 | opt_recv->dccpor_timestamp_echo = ntohl(opt_val); |
| 168 | |
| 169 | dccp_pr_debug("%s rx opt: TIMESTAMP_ECHO=%u, len=%d, " |
| 170 | "ackno=%llu", dccp_role(sk), |
| 171 | opt_recv->dccpor_timestamp_echo, |
| 172 | len + 2, |
| 173 | (unsigned long long) |
| 174 | DCCP_SKB_CB(skb)->dccpd_ack_seq); |
| 175 | |
| 176 | value += 4; |
| 177 | |
| 178 | if (len == 4) { /* no elapsed time included */ |
| 179 | dccp_pr_debug_cat("\n"); |
| 180 | break; |
| 181 | } |
| 182 | |
| 183 | if (len == 6) { /* 2-byte elapsed time */ |
| 184 | __be16 opt_val2 = get_unaligned((__be16 *)value); |
| 185 | elapsed_time = ntohs(opt_val2); |
| 186 | } else { /* 4-byte elapsed time */ |
| 187 | opt_val = get_unaligned((__be32 *)value); |
| 188 | elapsed_time = ntohl(opt_val); |
| 189 | } |
| 190 | |
| 191 | dccp_pr_debug_cat(", ELAPSED_TIME=%u\n", elapsed_time); |
| 192 | |
| 193 | /* Give precedence to the biggest ELAPSED_TIME */ |
| 194 | if (elapsed_time > opt_recv->dccpor_elapsed_time) |
| 195 | opt_recv->dccpor_elapsed_time = elapsed_time; |
| 196 | break; |
| 197 | case DCCPO_ELAPSED_TIME: |
| 198 | if (dccp_packet_without_ack(skb)) /* RFC 4340, 13.2 */ |
| 199 | break; |
| 200 | |
| 201 | if (len == 2) { |
| 202 | __be16 opt_val2 = get_unaligned((__be16 *)value); |
| 203 | elapsed_time = ntohs(opt_val2); |
| 204 | } else if (len == 4) { |
| 205 | opt_val = get_unaligned((__be32 *)value); |
| 206 | elapsed_time = ntohl(opt_val); |
| 207 | } else { |
| 208 | goto out_invalid_option; |
| 209 | } |
| 210 | |
| 211 | if (elapsed_time > opt_recv->dccpor_elapsed_time) |
| 212 | opt_recv->dccpor_elapsed_time = elapsed_time; |
| 213 | |
| 214 | dccp_pr_debug("%s rx opt: ELAPSED_TIME=%d\n", |
| 215 | dccp_role(sk), elapsed_time); |
| 216 | break; |
| 217 | case DCCPO_MIN_RX_CCID_SPECIFIC ... DCCPO_MAX_RX_CCID_SPECIFIC: |
| 218 | if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk, |
| 219 | pkt_type, opt, value, len)) |
| 220 | goto out_invalid_option; |
| 221 | break; |
| 222 | case DCCPO_ACK_VECTOR_0: |
| 223 | case DCCPO_ACK_VECTOR_1: |
| 224 | if (dccp_packet_without_ack(skb)) /* RFC 4340, 11.4 */ |
| 225 | break; |
| 226 | /* |
| 227 | * Ack vectors are processed by the TX CCID if it is |
| 228 | * interested. The RX CCID need not parse Ack Vectors, |
| 229 | * since it is only interested in clearing old state. |
| 230 | * Fall through. |
| 231 | */ |
| 232 | case DCCPO_MIN_TX_CCID_SPECIFIC ... DCCPO_MAX_TX_CCID_SPECIFIC: |
| 233 | if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk, |
| 234 | pkt_type, opt, value, len)) |
| 235 | goto out_invalid_option; |
| 236 | break; |
| 237 | default: |
| 238 | DCCP_CRIT("DCCP(%p): option %d(len=%d) not " |
| 239 | "implemented, ignoring", sk, opt, len); |
| 240 | break; |
| 241 | } |
| 242 | ignore_option: |
| 243 | if (opt != DCCPO_MANDATORY) |
| 244 | mandatory = 0; |
| 245 | } |
| 246 | |
| 247 | /* mandatory was the last byte in option list -> reset connection */ |
| 248 | if (mandatory) |
| 249 | goto out_invalid_option; |
| 250 | |
| 251 | out_nonsensical_length: |
| 252 | /* RFC 4340, 5.8: ignore option and all remaining option space */ |
| 253 | return 0; |
| 254 | |
| 255 | out_invalid_option: |
| 256 | DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT); |
| 257 | rc = DCCP_RESET_CODE_OPTION_ERROR; |
| 258 | out_featneg_failed: |
| 259 | DCCP_WARN("DCCP(%p): Option %d (len=%d) error=%u\n", sk, opt, len, rc); |
| 260 | DCCP_SKB_CB(skb)->dccpd_reset_code = rc; |
| 261 | DCCP_SKB_CB(skb)->dccpd_reset_data[0] = opt; |
| 262 | DCCP_SKB_CB(skb)->dccpd_reset_data[1] = len > 0 ? value[0] : 0; |
| 263 | DCCP_SKB_CB(skb)->dccpd_reset_data[2] = len > 1 ? value[1] : 0; |
| 264 | return -1; |
| 265 | } |
| 266 | |
| 267 | EXPORT_SYMBOL_GPL(dccp_parse_options); |
| 268 | |
| 269 | void dccp_encode_value_var(const u64 value, u8 *to, const u8 len) |
| 270 | { |
| 271 | if (len >= DCCP_OPTVAL_MAXLEN) |
| 272 | *to++ = (value & 0xFF0000000000ull) >> 40; |
| 273 | if (len > 4) |
| 274 | *to++ = (value & 0xFF00000000ull) >> 32; |
| 275 | if (len > 3) |
| 276 | *to++ = (value & 0xFF000000) >> 24; |
| 277 | if (len > 2) |
| 278 | *to++ = (value & 0xFF0000) >> 16; |
| 279 | if (len > 1) |
| 280 | *to++ = (value & 0xFF00) >> 8; |
| 281 | if (len > 0) |
| 282 | *to++ = (value & 0xFF); |
| 283 | } |
| 284 | |
| 285 | static inline u8 dccp_ndp_len(const u64 ndp) |
| 286 | { |
| 287 | if (likely(ndp <= 0xFF)) |
| 288 | return 1; |
| 289 | return likely(ndp <= USHRT_MAX) ? 2 : (ndp <= UINT_MAX ? 4 : 6); |
| 290 | } |
| 291 | |
| 292 | int dccp_insert_option(struct sk_buff *skb, const unsigned char option, |
| 293 | const void *value, const unsigned char len) |
| 294 | { |
| 295 | unsigned char *to; |
| 296 | |
| 297 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) |
| 298 | return -1; |
| 299 | |
| 300 | DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2; |
| 301 | |
| 302 | to = skb_push(skb, len + 2); |
| 303 | *to++ = option; |
| 304 | *to++ = len + 2; |
| 305 | |
| 306 | memcpy(to, value, len); |
| 307 | return 0; |
| 308 | } |
| 309 | |
| 310 | EXPORT_SYMBOL_GPL(dccp_insert_option); |
| 311 | |
| 312 | static int dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb) |
| 313 | { |
| 314 | struct dccp_sock *dp = dccp_sk(sk); |
| 315 | u64 ndp = dp->dccps_ndp_count; |
| 316 | |
| 317 | if (dccp_non_data_packet(skb)) |
| 318 | ++dp->dccps_ndp_count; |
| 319 | else |
| 320 | dp->dccps_ndp_count = 0; |
| 321 | |
| 322 | if (ndp > 0) { |
| 323 | unsigned char *ptr; |
| 324 | const int ndp_len = dccp_ndp_len(ndp); |
| 325 | const int len = ndp_len + 2; |
| 326 | |
| 327 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
| 328 | return -1; |
| 329 | |
| 330 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
| 331 | |
| 332 | ptr = skb_push(skb, len); |
| 333 | *ptr++ = DCCPO_NDP_COUNT; |
| 334 | *ptr++ = len; |
| 335 | dccp_encode_value_var(ndp, ptr, ndp_len); |
| 336 | } |
| 337 | |
| 338 | return 0; |
| 339 | } |
| 340 | |
| 341 | static inline int dccp_elapsed_time_len(const u32 elapsed_time) |
| 342 | { |
| 343 | return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4; |
| 344 | } |
| 345 | |
| 346 | /* FIXME: This function is currently not used anywhere */ |
| 347 | int dccp_insert_option_elapsed_time(struct sk_buff *skb, u32 elapsed_time) |
| 348 | { |
| 349 | const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); |
| 350 | const int len = 2 + elapsed_time_len; |
| 351 | unsigned char *to; |
| 352 | |
| 353 | if (elapsed_time_len == 0) |
| 354 | return 0; |
| 355 | |
| 356 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
| 357 | return -1; |
| 358 | |
| 359 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
| 360 | |
| 361 | to = skb_push(skb, len); |
| 362 | *to++ = DCCPO_ELAPSED_TIME; |
| 363 | *to++ = len; |
| 364 | |
| 365 | if (elapsed_time_len == 2) { |
| 366 | const __be16 var16 = htons((u16)elapsed_time); |
| 367 | memcpy(to, &var16, 2); |
| 368 | } else { |
| 369 | const __be32 var32 = htonl(elapsed_time); |
| 370 | memcpy(to, &var32, 4); |
| 371 | } |
| 372 | |
| 373 | return 0; |
| 374 | } |
| 375 | |
| 376 | EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time); |
| 377 | |
| 378 | static int dccp_insert_option_timestamp(struct sk_buff *skb) |
| 379 | { |
| 380 | __be32 now = htonl(dccp_timestamp()); |
| 381 | /* yes this will overflow but that is the point as we want a |
| 382 | * 10 usec 32 bit timer which mean it wraps every 11.9 hours */ |
| 383 | |
| 384 | return dccp_insert_option(skb, DCCPO_TIMESTAMP, &now, sizeof(now)); |
| 385 | } |
| 386 | |
| 387 | static int dccp_insert_option_timestamp_echo(struct dccp_sock *dp, |
| 388 | struct dccp_request_sock *dreq, |
| 389 | struct sk_buff *skb) |
| 390 | { |
| 391 | __be32 tstamp_echo; |
| 392 | unsigned char *to; |
| 393 | u32 elapsed_time, elapsed_time_len, len; |
| 394 | |
| 395 | if (dreq != NULL) { |
| 396 | elapsed_time = dccp_timestamp() - dreq->dreq_timestamp_time; |
| 397 | tstamp_echo = htonl(dreq->dreq_timestamp_echo); |
| 398 | dreq->dreq_timestamp_echo = 0; |
| 399 | } else { |
| 400 | elapsed_time = dccp_timestamp() - dp->dccps_timestamp_time; |
| 401 | tstamp_echo = htonl(dp->dccps_timestamp_echo); |
| 402 | dp->dccps_timestamp_echo = 0; |
| 403 | } |
| 404 | |
| 405 | elapsed_time_len = dccp_elapsed_time_len(elapsed_time); |
| 406 | len = 6 + elapsed_time_len; |
| 407 | |
| 408 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) |
| 409 | return -1; |
| 410 | |
| 411 | DCCP_SKB_CB(skb)->dccpd_opt_len += len; |
| 412 | |
| 413 | to = skb_push(skb, len); |
| 414 | *to++ = DCCPO_TIMESTAMP_ECHO; |
| 415 | *to++ = len; |
| 416 | |
| 417 | memcpy(to, &tstamp_echo, 4); |
| 418 | to += 4; |
| 419 | |
| 420 | if (elapsed_time_len == 2) { |
| 421 | const __be16 var16 = htons((u16)elapsed_time); |
| 422 | memcpy(to, &var16, 2); |
| 423 | } else if (elapsed_time_len == 4) { |
| 424 | const __be32 var32 = htonl(elapsed_time); |
| 425 | memcpy(to, &var32, 4); |
| 426 | } |
| 427 | |
| 428 | return 0; |
| 429 | } |
| 430 | |
| 431 | static int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb) |
| 432 | { |
| 433 | struct dccp_sock *dp = dccp_sk(sk); |
| 434 | struct dccp_ackvec *av = dp->dccps_hc_rx_ackvec; |
| 435 | struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb); |
| 436 | const u16 buflen = dccp_ackvec_buflen(av); |
| 437 | /* Figure out how many options do we need to represent the ackvec */ |
| 438 | const u8 nr_opts = DIV_ROUND_UP(buflen, DCCP_SINGLE_OPT_MAXLEN); |
| 439 | u16 len = buflen + 2 * nr_opts; |
| 440 | u8 i, nonce = 0; |
| 441 | const unsigned char *tail, *from; |
| 442 | unsigned char *to; |
| 443 | |
| 444 | if (dcb->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) { |
| 445 | DCCP_WARN("Lacking space for %u bytes on %s packet\n", len, |
| 446 | dccp_packet_name(dcb->dccpd_type)); |
| 447 | return -1; |
| 448 | } |
| 449 | /* |
| 450 | * Since Ack Vectors are variable-length, we can not always predict |
| 451 | * their size. To catch exception cases where the space is running out |
| 452 | * on the skb, a separate Sync is scheduled to carry the Ack Vector. |
| 453 | */ |
| 454 | if (len > DCCPAV_MIN_OPTLEN && |
| 455 | len + dcb->dccpd_opt_len + skb->len > dp->dccps_mss_cache) { |
| 456 | DCCP_WARN("No space left for Ack Vector (%u) on skb (%u+%u), " |
| 457 | "MPS=%u ==> reduce payload size?\n", len, skb->len, |
| 458 | dcb->dccpd_opt_len, dp->dccps_mss_cache); |
| 459 | dp->dccps_sync_scheduled = 1; |
| 460 | return 0; |
| 461 | } |
| 462 | dcb->dccpd_opt_len += len; |
| 463 | |
| 464 | to = skb_push(skb, len); |
| 465 | len = buflen; |
| 466 | from = av->av_buf + av->av_buf_head; |
| 467 | tail = av->av_buf + DCCPAV_MAX_ACKVEC_LEN; |
| 468 | |
| 469 | for (i = 0; i < nr_opts; ++i) { |
| 470 | int copylen = len; |
| 471 | |
| 472 | if (len > DCCP_SINGLE_OPT_MAXLEN) |
| 473 | copylen = DCCP_SINGLE_OPT_MAXLEN; |
| 474 | |
| 475 | /* |
| 476 | * RFC 4340, 12.2: Encode the Nonce Echo for this Ack Vector via |
| 477 | * its type; ack_nonce is the sum of all individual buf_nonce's. |
| 478 | */ |
| 479 | nonce ^= av->av_buf_nonce[i]; |
| 480 | |
| 481 | *to++ = DCCPO_ACK_VECTOR_0 + av->av_buf_nonce[i]; |
| 482 | *to++ = copylen + 2; |
| 483 | |
| 484 | /* Check if buf_head wraps */ |
| 485 | if (from + copylen > tail) { |
| 486 | const u16 tailsize = tail - from; |
| 487 | |
| 488 | memcpy(to, from, tailsize); |
| 489 | to += tailsize; |
| 490 | len -= tailsize; |
| 491 | copylen -= tailsize; |
| 492 | from = av->av_buf; |
| 493 | } |
| 494 | |
| 495 | memcpy(to, from, copylen); |
| 496 | from += copylen; |
| 497 | to += copylen; |
| 498 | len -= copylen; |
| 499 | } |
| 500 | /* |
| 501 | * Each sent Ack Vector is recorded in the list, as per A.2 of RFC 4340. |
| 502 | */ |
| 503 | if (dccp_ackvec_update_records(av, dcb->dccpd_seq, nonce)) |
| 504 | return -ENOBUFS; |
| 505 | return 0; |
| 506 | } |
| 507 | |
| 508 | /** |
| 509 | * dccp_insert_option_mandatory - Mandatory option (5.8.2) |
| 510 | * Note that since we are using skb_push, this function needs to be called |
| 511 | * _after_ inserting the option it is supposed to influence (stack order). |
| 512 | */ |
| 513 | int dccp_insert_option_mandatory(struct sk_buff *skb) |
| 514 | { |
| 515 | if (DCCP_SKB_CB(skb)->dccpd_opt_len >= DCCP_MAX_OPT_LEN) |
| 516 | return -1; |
| 517 | |
| 518 | DCCP_SKB_CB(skb)->dccpd_opt_len++; |
| 519 | *skb_push(skb, 1) = DCCPO_MANDATORY; |
| 520 | return 0; |
| 521 | } |
| 522 | |
| 523 | /** |
| 524 | * dccp_insert_fn_opt - Insert single Feature-Negotiation option into @skb |
| 525 | * @type: %DCCPO_CHANGE_L, %DCCPO_CHANGE_R, %DCCPO_CONFIRM_L, %DCCPO_CONFIRM_R |
| 526 | * @feat: one out of %dccp_feature_numbers |
| 527 | * @val: NN value or SP array (preferred element first) to copy |
| 528 | * @len: true length of @val in bytes (excluding first element repetition) |
| 529 | * @repeat_first: whether to copy the first element of @val twice |
| 530 | * |
| 531 | * The last argument is used to construct Confirm options, where the preferred |
| 532 | * value and the preference list appear separately (RFC 4340, 6.3.1). Preference |
| 533 | * lists are kept such that the preferred entry is always first, so we only need |
| 534 | * to copy twice, and avoid the overhead of cloning into a bigger array. |
| 535 | */ |
| 536 | int dccp_insert_fn_opt(struct sk_buff *skb, u8 type, u8 feat, |
| 537 | u8 *val, u8 len, bool repeat_first) |
| 538 | { |
| 539 | u8 tot_len, *to; |
| 540 | |
| 541 | /* take the `Feature' field and possible repetition into account */ |
| 542 | if (len > (DCCP_SINGLE_OPT_MAXLEN - 2)) { |
| 543 | DCCP_WARN("length %u for feature %u too large\n", len, feat); |
| 544 | return -1; |
| 545 | } |
| 546 | |
| 547 | if (unlikely(val == NULL || len == 0)) |
| 548 | len = repeat_first = false; |
| 549 | tot_len = 3 + repeat_first + len; |
| 550 | |
| 551 | if (DCCP_SKB_CB(skb)->dccpd_opt_len + tot_len > DCCP_MAX_OPT_LEN) { |
| 552 | DCCP_WARN("packet too small for feature %d option!\n", feat); |
| 553 | return -1; |
| 554 | } |
| 555 | DCCP_SKB_CB(skb)->dccpd_opt_len += tot_len; |
| 556 | |
| 557 | to = skb_push(skb, tot_len); |
| 558 | *to++ = type; |
| 559 | *to++ = tot_len; |
| 560 | *to++ = feat; |
| 561 | |
| 562 | if (repeat_first) |
| 563 | *to++ = *val; |
| 564 | if (len) |
| 565 | memcpy(to, val, len); |
| 566 | return 0; |
| 567 | } |
| 568 | |
| 569 | /* The length of all options needs to be a multiple of 4 (5.8) */ |
| 570 | static void dccp_insert_option_padding(struct sk_buff *skb) |
| 571 | { |
| 572 | int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4; |
| 573 | |
| 574 | if (padding != 0) { |
| 575 | padding = 4 - padding; |
| 576 | memset(skb_push(skb, padding), 0, padding); |
| 577 | DCCP_SKB_CB(skb)->dccpd_opt_len += padding; |
| 578 | } |
| 579 | } |
| 580 | |
| 581 | int dccp_insert_options(struct sock *sk, struct sk_buff *skb) |
| 582 | { |
| 583 | struct dccp_sock *dp = dccp_sk(sk); |
| 584 | |
| 585 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
| 586 | |
| 587 | if (dp->dccps_send_ndp_count && dccp_insert_option_ndp(sk, skb)) |
| 588 | return -1; |
| 589 | |
| 590 | if (DCCP_SKB_CB(skb)->dccpd_type != DCCP_PKT_DATA) { |
| 591 | |
| 592 | /* Feature Negotiation */ |
| 593 | if (dccp_feat_insert_opts(dp, NULL, skb)) |
| 594 | return -1; |
| 595 | |
| 596 | if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST) { |
| 597 | /* |
| 598 | * Obtain RTT sample from Request/Response exchange. |
| 599 | * This is currently used for TFRC initialisation. |
| 600 | */ |
| 601 | if (dccp_insert_option_timestamp(skb)) |
| 602 | return -1; |
| 603 | |
| 604 | } else if (dccp_ackvec_pending(sk) && |
| 605 | dccp_insert_option_ackvec(sk, skb)) { |
| 606 | return -1; |
| 607 | } |
| 608 | } |
| 609 | |
| 610 | if (dp->dccps_hc_rx_insert_options) { |
| 611 | if (ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb)) |
| 612 | return -1; |
| 613 | dp->dccps_hc_rx_insert_options = 0; |
| 614 | } |
| 615 | |
| 616 | if (dp->dccps_timestamp_echo != 0 && |
| 617 | dccp_insert_option_timestamp_echo(dp, NULL, skb)) |
| 618 | return -1; |
| 619 | |
| 620 | dccp_insert_option_padding(skb); |
| 621 | return 0; |
| 622 | } |
| 623 | |
| 624 | int dccp_insert_options_rsk(struct dccp_request_sock *dreq, struct sk_buff *skb) |
| 625 | { |
| 626 | DCCP_SKB_CB(skb)->dccpd_opt_len = 0; |
| 627 | |
| 628 | if (dccp_feat_insert_opts(NULL, dreq, skb)) |
| 629 | return -1; |
| 630 | |
| 631 | /* Obtain RTT sample from Response/Ack exchange (used by TFRC). */ |
| 632 | if (dccp_insert_option_timestamp(skb)) |
| 633 | return -1; |
| 634 | |
| 635 | if (dreq->dreq_timestamp_echo != 0 && |
| 636 | dccp_insert_option_timestamp_echo(NULL, dreq, skb)) |
| 637 | return -1; |
| 638 | |
| 639 | dccp_insert_option_padding(skb); |
| 640 | return 0; |
| 641 | } |