| | 1 | // SPDX-License-Identifier: GPL-2.0 |
| | 2 | /* Multipath TCP |
| | 3 | * |
| | 4 | * Copyright (c) 2017 - 2019, Intel Corporation. |
| | 5 | */ |
| | 6 | |
| | 7 | #define pr_fmt(fmt) "MPTCP: " fmt |
| | 8 | |
| | 9 | #include <linux/kernel.h> |
| | 10 | #include <crypto/sha2.h> |
| | 11 | #include <net/tcp.h> |
| | 12 | #include <net/mptcp.h> |
| | 13 | #include "protocol.h" |
| | 14 | #include "mib.h" |
| | 15 | |
| | 16 | #include <trace/events/mptcp.h> |
| | 17 | |
| | 18 | static bool mptcp_cap_flag_sha256(u8 flags) |
| | 19 | { |
| | 20 | return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; |
| | 21 | } |
| | 22 | |
| | 23 | static void mptcp_parse_option(const struct sk_buff *skb, |
| | 24 | const unsigned char *ptr, int opsize, |
| | 25 | struct mptcp_options_received *mp_opt) |
| | 26 | { |
| | 27 | u8 subtype = *ptr >> 4; |
| | 28 | int expected_opsize; |
| | 29 | u16 subopt; |
| | 30 | u8 version; |
| | 31 | u8 flags; |
| | 32 | u8 i; |
| | 33 | |
| | 34 | switch (subtype) { |
| | 35 | case MPTCPOPT_MP_CAPABLE: |
| | 36 | /* strict size checking */ |
| | 37 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
| | 38 | if (skb->len > tcp_hdr(skb)->doff << 2) |
| | 39 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; |
| | 40 | else |
| | 41 | expected_opsize = TCPOLEN_MPTCP_MPC_ACK; |
| | 42 | subopt = OPTION_MPTCP_MPC_ACK; |
| | 43 | } else { |
| | 44 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) { |
| | 45 | expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; |
| | 46 | subopt = OPTION_MPTCP_MPC_SYNACK; |
| | 47 | } else { |
| | 48 | expected_opsize = TCPOLEN_MPTCP_MPC_SYN; |
| | 49 | subopt = OPTION_MPTCP_MPC_SYN; |
| | 50 | } |
| | 51 | } |
| | 52 | |
| | 53 | /* Cfr RFC 8684 Section 3.3.0: |
| | 54 | * If a checksum is present but its use had |
| | 55 | * not been negotiated in the MP_CAPABLE handshake, the receiver MUST |
| | 56 | * close the subflow with a RST, as it is not behaving as negotiated. |
| | 57 | * If a checksum is not present when its use has been negotiated, the |
| | 58 | * receiver MUST close the subflow with a RST, as it is considered |
| | 59 | * broken |
| | 60 | * We parse even option with mismatching csum presence, so that |
| | 61 | * later in subflow_data_ready we can trigger the reset. |
| | 62 | */ |
| | 63 | if (opsize != expected_opsize && |
| | 64 | (expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA || |
| | 65 | opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM)) |
| | 66 | break; |
| | 67 | |
| | 68 | /* try to be gentle vs future versions on the initial syn */ |
| | 69 | version = *ptr++ & MPTCP_VERSION_MASK; |
| | 70 | if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
| | 71 | if (version != MPTCP_SUPPORTED_VERSION) |
| | 72 | break; |
| | 73 | } else if (version < MPTCP_SUPPORTED_VERSION) { |
| | 74 | break; |
| | 75 | } |
| | 76 | |
| | 77 | flags = *ptr++; |
| | 78 | if (!mptcp_cap_flag_sha256(flags) || |
| | 79 | (flags & MPTCP_CAP_EXTENSIBILITY)) |
| | 80 | break; |
| | 81 | |
| | 82 | /* RFC 6824, Section 3.1: |
| | 83 | * "For the Checksum Required bit (labeled "A"), if either |
| | 84 | * host requires the use of checksums, checksums MUST be used. |
| | 85 | * In other words, the only way for checksums not to be used |
| | 86 | * is if both hosts in their SYNs set A=0." |
| | 87 | */ |
| | 88 | if (flags & MPTCP_CAP_CHECKSUM_REQD) |
| | 89 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| | 90 | |
| | 91 | mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0); |
| | 92 | |
| | 93 | mp_opt->suboptions |= subopt; |
| | 94 | if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
| | 95 | mp_opt->sndr_key = get_unaligned_be64(ptr); |
| | 96 | ptr += 8; |
| | 97 | } |
| | 98 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { |
| | 99 | mp_opt->rcvr_key = get_unaligned_be64(ptr); |
| | 100 | ptr += 8; |
| | 101 | } |
| | 102 | if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) { |
| | 103 | /* Section 3.1.: |
| | 104 | * "the data parameters in a MP_CAPABLE are semantically |
| | 105 | * equivalent to those in a DSS option and can be used |
| | 106 | * interchangeably." |
| | 107 | */ |
| | 108 | mp_opt->suboptions |= OPTION_MPTCP_DSS; |
| | 109 | mp_opt->use_map = 1; |
| | 110 | mp_opt->mpc_map = 1; |
| | 111 | mp_opt->data_len = get_unaligned_be16(ptr); |
| | 112 | ptr += 2; |
| | 113 | } |
| | 114 | if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) { |
| | 115 | mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
| | 116 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| | 117 | ptr += 2; |
| | 118 | } |
| | 119 | pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u\n", |
| | 120 | version, flags, opsize, mp_opt->sndr_key, |
| | 121 | mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum); |
| | 122 | break; |
| | 123 | |
| | 124 | case MPTCPOPT_MP_JOIN: |
| | 125 | if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { |
| | 126 | mp_opt->suboptions |= OPTION_MPTCP_MPJ_SYN; |
| | 127 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
| | 128 | mp_opt->join_id = *ptr++; |
| | 129 | mp_opt->token = get_unaligned_be32(ptr); |
| | 130 | ptr += 4; |
| | 131 | mp_opt->nonce = get_unaligned_be32(ptr); |
| | 132 | ptr += 4; |
| | 133 | pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u\n", |
| | 134 | mp_opt->backup, mp_opt->join_id, |
| | 135 | mp_opt->token, mp_opt->nonce); |
| | 136 | } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { |
| | 137 | mp_opt->suboptions |= OPTION_MPTCP_MPJ_SYNACK; |
| | 138 | mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
| | 139 | mp_opt->join_id = *ptr++; |
| | 140 | mp_opt->thmac = get_unaligned_be64(ptr); |
| | 141 | ptr += 8; |
| | 142 | mp_opt->nonce = get_unaligned_be32(ptr); |
| | 143 | ptr += 4; |
| | 144 | pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u\n", |
| | 145 | mp_opt->backup, mp_opt->join_id, |
| | 146 | mp_opt->thmac, mp_opt->nonce); |
| | 147 | } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { |
| | 148 | mp_opt->suboptions |= OPTION_MPTCP_MPJ_ACK; |
| | 149 | ptr += 2; |
| | 150 | memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); |
| | 151 | pr_debug("MP_JOIN hmac\n"); |
| | 152 | } |
| | 153 | break; |
| | 154 | |
| | 155 | case MPTCPOPT_DSS: |
| | 156 | pr_debug("DSS\n"); |
| | 157 | ptr++; |
| | 158 | |
| | 159 | flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
| | 160 | mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; |
| | 161 | mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; |
| | 162 | mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; |
| | 163 | mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; |
| | 164 | mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); |
| | 165 | |
| | 166 | pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d\n", |
| | 167 | mp_opt->data_fin, mp_opt->dsn64, |
| | 168 | mp_opt->use_map, mp_opt->ack64, |
| | 169 | mp_opt->use_ack); |
| | 170 | |
| | 171 | expected_opsize = TCPOLEN_MPTCP_DSS_BASE; |
| | 172 | |
| | 173 | if (mp_opt->use_ack) { |
| | 174 | if (mp_opt->ack64) |
| | 175 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; |
| | 176 | else |
| | 177 | expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; |
| | 178 | } |
| | 179 | |
| | 180 | if (mp_opt->use_map) { |
| | 181 | if (mp_opt->dsn64) |
| | 182 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; |
| | 183 | else |
| | 184 | expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; |
| | 185 | } |
| | 186 | |
| | 187 | /* Always parse any csum presence combination, we will enforce |
| | 188 | * RFC 8684 Section 3.3.0 checks later in subflow_data_ready |
| | 189 | */ |
| | 190 | if (opsize != expected_opsize && |
| | 191 | opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) |
| | 192 | break; |
| | 193 | |
| | 194 | mp_opt->suboptions |= OPTION_MPTCP_DSS; |
| | 195 | if (mp_opt->use_ack) { |
| | 196 | if (mp_opt->ack64) { |
| | 197 | mp_opt->data_ack = get_unaligned_be64(ptr); |
| | 198 | ptr += 8; |
| | 199 | } else { |
| | 200 | mp_opt->data_ack = get_unaligned_be32(ptr); |
| | 201 | ptr += 4; |
| | 202 | } |
| | 203 | |
| | 204 | pr_debug("data_ack=%llu\n", mp_opt->data_ack); |
| | 205 | } |
| | 206 | |
| | 207 | if (mp_opt->use_map) { |
| | 208 | if (mp_opt->dsn64) { |
| | 209 | mp_opt->data_seq = get_unaligned_be64(ptr); |
| | 210 | ptr += 8; |
| | 211 | } else { |
| | 212 | mp_opt->data_seq = get_unaligned_be32(ptr); |
| | 213 | ptr += 4; |
| | 214 | } |
| | 215 | |
| | 216 | mp_opt->subflow_seq = get_unaligned_be32(ptr); |
| | 217 | ptr += 4; |
| | 218 | |
| | 219 | mp_opt->data_len = get_unaligned_be16(ptr); |
| | 220 | ptr += 2; |
| | 221 | |
| | 222 | if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) { |
| | 223 | mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| | 224 | mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
| | 225 | ptr += 2; |
| | 226 | } |
| | 227 | |
| | 228 | pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u\n", |
| | 229 | mp_opt->data_seq, mp_opt->subflow_seq, |
| | 230 | mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD), |
| | 231 | mp_opt->csum); |
| | 232 | } |
| | 233 | |
| | 234 | break; |
| | 235 | |
| | 236 | case MPTCPOPT_ADD_ADDR: |
| | 237 | mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; |
| | 238 | if (!mp_opt->echo) { |
| | 239 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR || |
| | 240 | opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) |
| | 241 | mp_opt->addr.family = AF_INET; |
| | 242 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 243 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || |
| | 244 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) |
| | 245 | mp_opt->addr.family = AF_INET6; |
| | 246 | #endif |
| | 247 | else |
| | 248 | break; |
| | 249 | } else { |
| | 250 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || |
| | 251 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) |
| | 252 | mp_opt->addr.family = AF_INET; |
| | 253 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 254 | else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || |
| | 255 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) |
| | 256 | mp_opt->addr.family = AF_INET6; |
| | 257 | #endif |
| | 258 | else |
| | 259 | break; |
| | 260 | } |
| | 261 | |
| | 262 | mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR; |
| | 263 | mp_opt->addr.id = *ptr++; |
| | 264 | mp_opt->addr.port = 0; |
| | 265 | mp_opt->ahmac = 0; |
| | 266 | if (mp_opt->addr.family == AF_INET) { |
| | 267 | memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4); |
| | 268 | ptr += 4; |
| | 269 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || |
| | 270 | opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { |
| | 271 | mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
| | 272 | ptr += 2; |
| | 273 | } |
| | 274 | } |
| | 275 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 276 | else { |
| | 277 | memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16); |
| | 278 | ptr += 16; |
| | 279 | if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || |
| | 280 | opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { |
| | 281 | mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
| | 282 | ptr += 2; |
| | 283 | } |
| | 284 | } |
| | 285 | #endif |
| | 286 | if (!mp_opt->echo) { |
| | 287 | mp_opt->ahmac = get_unaligned_be64(ptr); |
| | 288 | ptr += 8; |
| | 289 | } |
| | 290 | pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d\n", |
| | 291 | (mp_opt->addr.family == AF_INET6) ? "6" : "", |
| | 292 | mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port)); |
| | 293 | break; |
| | 294 | |
| | 295 | case MPTCPOPT_RM_ADDR: |
| | 296 | if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || |
| | 297 | opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) |
| | 298 | break; |
| | 299 | |
| | 300 | ptr++; |
| | 301 | |
| | 302 | mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR; |
| | 303 | mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; |
| | 304 | for (i = 0; i < mp_opt->rm_list.nr; i++) |
| | 305 | mp_opt->rm_list.ids[i] = *ptr++; |
| | 306 | pr_debug("RM_ADDR: rm_list_nr=%d\n", mp_opt->rm_list.nr); |
| | 307 | break; |
| | 308 | |
| | 309 | case MPTCPOPT_MP_PRIO: |
| | 310 | if (opsize != TCPOLEN_MPTCP_PRIO) |
| | 311 | break; |
| | 312 | |
| | 313 | mp_opt->suboptions |= OPTION_MPTCP_PRIO; |
| | 314 | mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; |
| | 315 | pr_debug("MP_PRIO: prio=%d\n", mp_opt->backup); |
| | 316 | break; |
| | 317 | |
| | 318 | case MPTCPOPT_MP_FASTCLOSE: |
| | 319 | if (opsize != TCPOLEN_MPTCP_FASTCLOSE) |
| | 320 | break; |
| | 321 | |
| | 322 | ptr += 2; |
| | 323 | mp_opt->rcvr_key = get_unaligned_be64(ptr); |
| | 324 | ptr += 8; |
| | 325 | mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE; |
| | 326 | pr_debug("MP_FASTCLOSE: recv_key=%llu\n", mp_opt->rcvr_key); |
| | 327 | break; |
| | 328 | |
| | 329 | case MPTCPOPT_RST: |
| | 330 | if (opsize != TCPOLEN_MPTCP_RST) |
| | 331 | break; |
| | 332 | |
| | 333 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) |
| | 334 | break; |
| | 335 | |
| | 336 | mp_opt->suboptions |= OPTION_MPTCP_RST; |
| | 337 | flags = *ptr++; |
| | 338 | mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT; |
| | 339 | mp_opt->reset_reason = *ptr; |
| | 340 | pr_debug("MP_RST: transient=%u reason=%u\n", |
| | 341 | mp_opt->reset_transient, mp_opt->reset_reason); |
| | 342 | break; |
| | 343 | |
| | 344 | case MPTCPOPT_MP_FAIL: |
| | 345 | if (opsize != TCPOLEN_MPTCP_FAIL) |
| | 346 | break; |
| | 347 | |
| | 348 | ptr += 2; |
| | 349 | mp_opt->suboptions |= OPTION_MPTCP_FAIL; |
| | 350 | mp_opt->fail_seq = get_unaligned_be64(ptr); |
| | 351 | pr_debug("MP_FAIL: data_seq=%llu\n", mp_opt->fail_seq); |
| | 352 | break; |
| | 353 | |
| | 354 | default: |
| | 355 | break; |
| | 356 | } |
| | 357 | } |
| | 358 | |
| | 359 | void mptcp_get_options(const struct sk_buff *skb, |
| | 360 | struct mptcp_options_received *mp_opt) |
| | 361 | { |
| | 362 | const struct tcphdr *th = tcp_hdr(skb); |
| | 363 | const unsigned char *ptr; |
| | 364 | int length; |
| | 365 | |
| | 366 | /* Ensure that casting the whole status to u32 is efficient and safe */ |
| | 367 | BUILD_BUG_ON(sizeof_field(struct mptcp_options_received, status) != sizeof(u32)); |
| | 368 | BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct mptcp_options_received, status), |
| | 369 | sizeof(u32))); |
| | 370 | *(u32 *)&mp_opt->status = 0; |
| | 371 | |
| | 372 | length = (th->doff * 4) - sizeof(struct tcphdr); |
| | 373 | ptr = (const unsigned char *)(th + 1); |
| | 374 | |
| | 375 | while (length > 0) { |
| | 376 | int opcode = *ptr++; |
| | 377 | int opsize; |
| | 378 | |
| | 379 | switch (opcode) { |
| | 380 | case TCPOPT_EOL: |
| | 381 | return; |
| | 382 | case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
| | 383 | length--; |
| | 384 | continue; |
| | 385 | default: |
| | 386 | if (length < 2) |
| | 387 | return; |
| | 388 | opsize = *ptr++; |
| | 389 | if (opsize < 2) /* "silly options" */ |
| | 390 | return; |
| | 391 | if (opsize > length) |
| | 392 | return; /* don't parse partial options */ |
| | 393 | if (opcode == TCPOPT_MPTCP) |
| | 394 | mptcp_parse_option(skb, ptr, opsize, mp_opt); |
| | 395 | ptr += opsize - 2; |
| | 396 | length -= opsize; |
| | 397 | } |
| | 398 | } |
| | 399 | } |
| | 400 | |
| | 401 | bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
| | 402 | unsigned int *size, struct mptcp_out_options *opts) |
| | 403 | { |
| | 404 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 405 | |
| | 406 | /* we will use snd_isn to detect first pkt [re]transmission |
| | 407 | * in mptcp_established_options_mp() |
| | 408 | */ |
| | 409 | subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; |
| | 410 | if (subflow->request_mptcp) { |
| | 411 | opts->suboptions = OPTION_MPTCP_MPC_SYN; |
| | 412 | opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk)); |
| | 413 | opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk)); |
| | 414 | *size = TCPOLEN_MPTCP_MPC_SYN; |
| | 415 | return true; |
| | 416 | } else if (subflow->request_join) { |
| | 417 | pr_debug("remote_token=%u, nonce=%u\n", subflow->remote_token, |
| | 418 | subflow->local_nonce); |
| | 419 | opts->suboptions = OPTION_MPTCP_MPJ_SYN; |
| | 420 | opts->join_id = subflow->local_id; |
| | 421 | opts->token = subflow->remote_token; |
| | 422 | opts->nonce = subflow->local_nonce; |
| | 423 | opts->backup = subflow->request_bkup; |
| | 424 | *size = TCPOLEN_MPTCP_MPJ_SYN; |
| | 425 | return true; |
| | 426 | } |
| | 427 | return false; |
| | 428 | } |
| | 429 | |
| | 430 | static void clear_3rdack_retransmission(struct sock *sk) |
| | 431 | { |
| | 432 | struct inet_connection_sock *icsk = inet_csk(sk); |
| | 433 | |
| | 434 | sk_stop_timer(sk, &icsk->icsk_delack_timer); |
| | 435 | icsk->icsk_ack.ato = 0; |
| | 436 | icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); |
| | 437 | } |
| | 438 | |
| | 439 | static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb, |
| | 440 | bool snd_data_fin_enable, |
| | 441 | unsigned int *size, |
| | 442 | struct mptcp_out_options *opts) |
| | 443 | { |
| | 444 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 445 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 446 | struct mptcp_ext *mpext; |
| | 447 | unsigned int data_len; |
| | 448 | u8 len; |
| | 449 | |
| | 450 | /* When skb is not available, we better over-estimate the emitted |
| | 451 | * options len. A full DSS option (28 bytes) is longer than |
| | 452 | * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so |
| | 453 | * tell the caller to defer the estimate to |
| | 454 | * mptcp_established_options_dss(), which will reserve enough space. |
| | 455 | */ |
| | 456 | if (!skb) |
| | 457 | return false; |
| | 458 | |
| | 459 | /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ |
| | 460 | if (READ_ONCE(subflow->fully_established) || snd_data_fin_enable || |
| | 461 | subflow->snd_isn != TCP_SKB_CB(skb)->seq || |
| | 462 | sk->sk_state != TCP_ESTABLISHED) |
| | 463 | return false; |
| | 464 | |
| | 465 | if (subflow->mp_capable) { |
| | 466 | mpext = mptcp_get_ext(skb); |
| | 467 | data_len = mpext ? mpext->data_len : 0; |
| | 468 | |
| | 469 | /* we will check ops->data_len in mptcp_write_options() to |
| | 470 | * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and |
| | 471 | * TCPOLEN_MPTCP_MPC_ACK |
| | 472 | */ |
| | 473 | opts->data_len = data_len; |
| | 474 | opts->suboptions = OPTION_MPTCP_MPC_ACK; |
| | 475 | opts->sndr_key = subflow->local_key; |
| | 476 | opts->rcvr_key = subflow->remote_key; |
| | 477 | opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
| | 478 | opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk)); |
| | 479 | |
| | 480 | /* Section 3.1. |
| | 481 | * The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK |
| | 482 | * packets that start the first subflow of an MPTCP connection, |
| | 483 | * as well as the first packet that carries data |
| | 484 | */ |
| | 485 | if (data_len > 0) { |
| | 486 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
| | 487 | if (opts->csum_reqd) { |
| | 488 | /* we need to propagate more info to csum the pseudo hdr */ |
| | 489 | opts->data_seq = mpext->data_seq; |
| | 490 | opts->subflow_seq = mpext->subflow_seq; |
| | 491 | opts->csum = mpext->csum; |
| | 492 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
| | 493 | } |
| | 494 | *size = ALIGN(len, 4); |
| | 495 | } else { |
| | 496 | *size = TCPOLEN_MPTCP_MPC_ACK; |
| | 497 | } |
| | 498 | |
| | 499 | pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d\n", |
| | 500 | subflow, subflow->local_key, subflow->remote_key, |
| | 501 | data_len); |
| | 502 | |
| | 503 | return true; |
| | 504 | } else if (subflow->mp_join) { |
| | 505 | opts->suboptions = OPTION_MPTCP_MPJ_ACK; |
| | 506 | memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN); |
| | 507 | *size = TCPOLEN_MPTCP_MPJ_ACK; |
| | 508 | pr_debug("subflow=%p\n", subflow); |
| | 509 | |
| | 510 | /* we can use the full delegate action helper only from BH context |
| | 511 | * If we are in process context - sk is flushing the backlog at |
| | 512 | * socket lock release time - just set the appropriate flag, will |
| | 513 | * be handled by the release callback |
| | 514 | */ |
| | 515 | if (sock_owned_by_user(sk)) |
| | 516 | set_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status); |
| | 517 | else |
| | 518 | mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK); |
| | 519 | return true; |
| | 520 | } |
| | 521 | return false; |
| | 522 | } |
| | 523 | |
| | 524 | static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, |
| | 525 | struct sk_buff *skb, struct mptcp_ext *ext) |
| | 526 | { |
| | 527 | /* The write_seq value has already been incremented, so the actual |
| | 528 | * sequence number for the DATA_FIN is one less. |
| | 529 | */ |
| | 530 | u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1; |
| | 531 | |
| | 532 | if (!ext->use_map || !skb->len) { |
| | 533 | /* RFC6824 requires a DSS mapping with specific values |
| | 534 | * if DATA_FIN is set but no data payload is mapped |
| | 535 | */ |
| | 536 | ext->data_fin = 1; |
| | 537 | ext->use_map = 1; |
| | 538 | ext->dsn64 = 1; |
| | 539 | ext->data_seq = data_fin_tx_seq; |
| | 540 | ext->subflow_seq = 0; |
| | 541 | ext->data_len = 1; |
| | 542 | } else if (ext->data_seq + ext->data_len == data_fin_tx_seq) { |
| | 543 | /* If there's an existing DSS mapping and it is the |
| | 544 | * final mapping, DATA_FIN consumes 1 additional byte of |
| | 545 | * mapping space. |
| | 546 | */ |
| | 547 | ext->data_fin = 1; |
| | 548 | ext->data_len++; |
| | 549 | } |
| | 550 | } |
| | 551 | |
| | 552 | static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb, |
| | 553 | bool snd_data_fin_enable, |
| | 554 | unsigned int *size, |
| | 555 | struct mptcp_out_options *opts) |
| | 556 | { |
| | 557 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 558 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 559 | unsigned int dss_size = 0; |
| | 560 | struct mptcp_ext *mpext; |
| | 561 | unsigned int ack_size; |
| | 562 | bool ret = false; |
| | 563 | u64 ack_seq; |
| | 564 | |
| | 565 | opts->csum_reqd = READ_ONCE(msk->csum_enabled); |
| | 566 | mpext = skb ? mptcp_get_ext(skb) : NULL; |
| | 567 | |
| | 568 | if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) { |
| | 569 | unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64; |
| | 570 | |
| | 571 | if (mpext) { |
| | 572 | if (opts->csum_reqd) |
| | 573 | map_size += TCPOLEN_MPTCP_DSS_CHECKSUM; |
| | 574 | |
| | 575 | opts->ext_copy = *mpext; |
| | 576 | } |
| | 577 | |
| | 578 | dss_size = map_size; |
| | 579 | if (skb && snd_data_fin_enable) |
| | 580 | mptcp_write_data_fin(subflow, skb, &opts->ext_copy); |
| | 581 | opts->suboptions = OPTION_MPTCP_DSS; |
| | 582 | ret = true; |
| | 583 | } |
| | 584 | |
| | 585 | /* passive sockets msk will set the 'can_ack' after accept(), even |
| | 586 | * if the first subflow may have the already the remote key handy |
| | 587 | */ |
| | 588 | opts->ext_copy.use_ack = 0; |
| | 589 | if (!READ_ONCE(msk->can_ack)) { |
| | 590 | *size = ALIGN(dss_size, 4); |
| | 591 | return ret; |
| | 592 | } |
| | 593 | |
| | 594 | ack_seq = READ_ONCE(msk->ack_seq); |
| | 595 | if (READ_ONCE(msk->use_64bit_ack)) { |
| | 596 | ack_size = TCPOLEN_MPTCP_DSS_ACK64; |
| | 597 | opts->ext_copy.data_ack = ack_seq; |
| | 598 | opts->ext_copy.ack64 = 1; |
| | 599 | } else { |
| | 600 | ack_size = TCPOLEN_MPTCP_DSS_ACK32; |
| | 601 | opts->ext_copy.data_ack32 = (uint32_t)ack_seq; |
| | 602 | opts->ext_copy.ack64 = 0; |
| | 603 | } |
| | 604 | opts->ext_copy.use_ack = 1; |
| | 605 | opts->suboptions = OPTION_MPTCP_DSS; |
| | 606 | |
| | 607 | /* Add kind/length/subtype/flag overhead if mapping is not populated */ |
| | 608 | if (dss_size == 0) |
| | 609 | ack_size += TCPOLEN_MPTCP_DSS_BASE; |
| | 610 | |
| | 611 | dss_size += ack_size; |
| | 612 | |
| | 613 | *size = ALIGN(dss_size, 4); |
| | 614 | return true; |
| | 615 | } |
| | 616 | |
| | 617 | static u64 add_addr_generate_hmac(u64 key1, u64 key2, |
| | 618 | struct mptcp_addr_info *addr) |
| | 619 | { |
| | 620 | u16 port = ntohs(addr->port); |
| | 621 | u8 hmac[SHA256_DIGEST_SIZE]; |
| | 622 | u8 msg[19]; |
| | 623 | int i = 0; |
| | 624 | |
| | 625 | msg[i++] = addr->id; |
| | 626 | if (addr->family == AF_INET) { |
| | 627 | memcpy(&msg[i], &addr->addr.s_addr, 4); |
| | 628 | i += 4; |
| | 629 | } |
| | 630 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 631 | else if (addr->family == AF_INET6) { |
| | 632 | memcpy(&msg[i], &addr->addr6.s6_addr, 16); |
| | 633 | i += 16; |
| | 634 | } |
| | 635 | #endif |
| | 636 | msg[i++] = port >> 8; |
| | 637 | msg[i++] = port & 0xFF; |
| | 638 | |
| | 639 | mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac); |
| | 640 | |
| | 641 | return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]); |
| | 642 | } |
| | 643 | |
| | 644 | static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb, |
| | 645 | unsigned int *size, |
| | 646 | unsigned int remaining, |
| | 647 | struct mptcp_out_options *opts) |
| | 648 | { |
| | 649 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 650 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 651 | bool drop_other_suboptions = false; |
| | 652 | unsigned int opt_size = *size; |
| | 653 | struct mptcp_addr_info addr; |
| | 654 | bool echo; |
| | 655 | int len; |
| | 656 | |
| | 657 | /* add addr will strip the existing options, be sure to avoid breaking |
| | 658 | * MPC/MPJ handshakes |
| | 659 | */ |
| | 660 | if (!mptcp_pm_should_add_signal(msk) || |
| | 661 | (opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) || |
| | 662 | !mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &addr, |
| | 663 | &echo, &drop_other_suboptions)) |
| | 664 | return false; |
| | 665 | |
| | 666 | /* |
| | 667 | * Later on, mptcp_write_options() will enforce mutually exclusion with |
| | 668 | * DSS, bail out if such option is set and we can't drop it. |
| | 669 | */ |
| | 670 | if (drop_other_suboptions) |
| | 671 | remaining += opt_size; |
| | 672 | else if (opts->suboptions & OPTION_MPTCP_DSS) |
| | 673 | return false; |
| | 674 | |
| | 675 | len = mptcp_add_addr_len(addr.family, echo, !!addr.port); |
| | 676 | if (remaining < len) |
| | 677 | return false; |
| | 678 | |
| | 679 | *size = len; |
| | 680 | if (drop_other_suboptions) { |
| | 681 | pr_debug("drop other suboptions\n"); |
| | 682 | opts->suboptions = 0; |
| | 683 | |
| | 684 | /* note that e.g. DSS could have written into the memory |
| | 685 | * aliased by ahmac, we must reset the field here |
| | 686 | * to avoid appending the hmac even for ADD_ADDR echo |
| | 687 | * options |
| | 688 | */ |
| | 689 | opts->ahmac = 0; |
| | 690 | *size -= opt_size; |
| | 691 | } |
| | 692 | opts->addr = addr; |
| | 693 | opts->suboptions |= OPTION_MPTCP_ADD_ADDR; |
| | 694 | if (!echo) { |
| | 695 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDRTX); |
| | 696 | opts->ahmac = add_addr_generate_hmac(READ_ONCE(msk->local_key), |
| | 697 | READ_ONCE(msk->remote_key), |
| | 698 | &opts->addr); |
| | 699 | } else { |
| | 700 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADDTX); |
| | 701 | } |
| | 702 | pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d\n", |
| | 703 | opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port)); |
| | 704 | |
| | 705 | return true; |
| | 706 | } |
| | 707 | |
| | 708 | static bool mptcp_established_options_rm_addr(struct sock *sk, |
| | 709 | unsigned int *size, |
| | 710 | unsigned int remaining, |
| | 711 | struct mptcp_out_options *opts) |
| | 712 | { |
| | 713 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 714 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 715 | struct mptcp_rm_list rm_list; |
| | 716 | int i, len; |
| | 717 | |
| | 718 | if (!mptcp_pm_should_rm_signal(msk) || |
| | 719 | !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list))) |
| | 720 | return false; |
| | 721 | |
| | 722 | len = mptcp_rm_addr_len(&rm_list); |
| | 723 | if (len < 0) |
| | 724 | return false; |
| | 725 | if (remaining < len) |
| | 726 | return false; |
| | 727 | |
| | 728 | *size = len; |
| | 729 | opts->suboptions |= OPTION_MPTCP_RM_ADDR; |
| | 730 | opts->rm_list = rm_list; |
| | 731 | |
| | 732 | for (i = 0; i < opts->rm_list.nr; i++) |
| | 733 | pr_debug("rm_list_ids[%d]=%d\n", i, opts->rm_list.ids[i]); |
| | 734 | MPTCP_ADD_STATS(sock_net(sk), MPTCP_MIB_RMADDRTX, opts->rm_list.nr); |
| | 735 | return true; |
| | 736 | } |
| | 737 | |
| | 738 | static bool mptcp_established_options_mp_prio(struct sock *sk, |
| | 739 | unsigned int *size, |
| | 740 | unsigned int remaining, |
| | 741 | struct mptcp_out_options *opts) |
| | 742 | { |
| | 743 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 744 | |
| | 745 | /* can't send MP_PRIO with MPC, as they share the same option space: |
| | 746 | * 'backup'. Also it makes no sense at all |
| | 747 | */ |
| | 748 | if (!subflow->send_mp_prio || (opts->suboptions & OPTIONS_MPTCP_MPC)) |
| | 749 | return false; |
| | 750 | |
| | 751 | /* account for the trailing 'nop' option */ |
| | 752 | if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN) |
| | 753 | return false; |
| | 754 | |
| | 755 | *size = TCPOLEN_MPTCP_PRIO_ALIGN; |
| | 756 | opts->suboptions |= OPTION_MPTCP_PRIO; |
| | 757 | opts->backup = subflow->request_bkup; |
| | 758 | |
| | 759 | pr_debug("prio=%d\n", opts->backup); |
| | 760 | |
| | 761 | return true; |
| | 762 | } |
| | 763 | |
| | 764 | static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb, |
| | 765 | unsigned int *size, |
| | 766 | unsigned int remaining, |
| | 767 | struct mptcp_out_options *opts) |
| | 768 | { |
| | 769 | const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 770 | |
| | 771 | if (remaining < TCPOLEN_MPTCP_RST) |
| | 772 | return false; |
| | 773 | |
| | 774 | *size = TCPOLEN_MPTCP_RST; |
| | 775 | opts->suboptions |= OPTION_MPTCP_RST; |
| | 776 | opts->reset_transient = subflow->reset_transient; |
| | 777 | opts->reset_reason = subflow->reset_reason; |
| | 778 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTTX); |
| | 779 | |
| | 780 | return true; |
| | 781 | } |
| | 782 | |
| | 783 | static bool mptcp_established_options_fastclose(struct sock *sk, |
| | 784 | unsigned int *size, |
| | 785 | unsigned int remaining, |
| | 786 | struct mptcp_out_options *opts) |
| | 787 | { |
| | 788 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 789 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 790 | |
| | 791 | if (likely(!subflow->send_fastclose)) |
| | 792 | return false; |
| | 793 | |
| | 794 | if (remaining < TCPOLEN_MPTCP_FASTCLOSE) |
| | 795 | return false; |
| | 796 | |
| | 797 | *size = TCPOLEN_MPTCP_FASTCLOSE; |
| | 798 | opts->suboptions |= OPTION_MPTCP_FASTCLOSE; |
| | 799 | opts->rcvr_key = READ_ONCE(msk->remote_key); |
| | 800 | |
| | 801 | pr_debug("FASTCLOSE key=%llu\n", opts->rcvr_key); |
| | 802 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSETX); |
| | 803 | return true; |
| | 804 | } |
| | 805 | |
| | 806 | static bool mptcp_established_options_mp_fail(struct sock *sk, |
| | 807 | unsigned int *size, |
| | 808 | unsigned int remaining, |
| | 809 | struct mptcp_out_options *opts) |
| | 810 | { |
| | 811 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 812 | |
| | 813 | if (likely(!subflow->send_mp_fail)) |
| | 814 | return false; |
| | 815 | |
| | 816 | if (remaining < TCPOLEN_MPTCP_FAIL) |
| | 817 | return false; |
| | 818 | |
| | 819 | *size = TCPOLEN_MPTCP_FAIL; |
| | 820 | opts->suboptions |= OPTION_MPTCP_FAIL; |
| | 821 | opts->fail_seq = subflow->map_seq; |
| | 822 | |
| | 823 | pr_debug("MP_FAIL fail_seq=%llu\n", opts->fail_seq); |
| | 824 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILTX); |
| | 825 | |
| | 826 | return true; |
| | 827 | } |
| | 828 | |
| | 829 | bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, |
| | 830 | unsigned int *size, unsigned int remaining, |
| | 831 | struct mptcp_out_options *opts) |
| | 832 | { |
| | 833 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 834 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 835 | unsigned int opt_size = 0; |
| | 836 | bool snd_data_fin; |
| | 837 | bool ret = false; |
| | 838 | |
| | 839 | opts->suboptions = 0; |
| | 840 | |
| | 841 | if (unlikely(__mptcp_check_fallback(msk) && !mptcp_check_infinite_map(skb))) |
| | 842 | return false; |
| | 843 | |
| | 844 | if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) { |
| | 845 | if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) || |
| | 846 | mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) { |
| | 847 | *size += opt_size; |
| | 848 | remaining -= opt_size; |
| | 849 | } |
| | 850 | /* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */ |
| | 851 | if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) { |
| | 852 | *size += opt_size; |
| | 853 | remaining -= opt_size; |
| | 854 | } |
| | 855 | return true; |
| | 856 | } |
| | 857 | |
| | 858 | snd_data_fin = mptcp_data_fin_enabled(msk); |
| | 859 | if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, opts)) |
| | 860 | ret = true; |
| | 861 | else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, opts)) { |
| | 862 | unsigned int mp_fail_size; |
| | 863 | |
| | 864 | ret = true; |
| | 865 | if (mptcp_established_options_mp_fail(sk, &mp_fail_size, |
| | 866 | remaining - opt_size, opts)) { |
| | 867 | *size += opt_size + mp_fail_size; |
| | 868 | remaining -= opt_size - mp_fail_size; |
| | 869 | return true; |
| | 870 | } |
| | 871 | } |
| | 872 | |
| | 873 | /* we reserved enough space for the above options, and exceeding the |
| | 874 | * TCP option space would be fatal |
| | 875 | */ |
| | 876 | if (WARN_ON_ONCE(opt_size > remaining)) |
| | 877 | return false; |
| | 878 | |
| | 879 | *size += opt_size; |
| | 880 | remaining -= opt_size; |
| | 881 | if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) { |
| | 882 | *size += opt_size; |
| | 883 | remaining -= opt_size; |
| | 884 | ret = true; |
| | 885 | } else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) { |
| | 886 | *size += opt_size; |
| | 887 | remaining -= opt_size; |
| | 888 | ret = true; |
| | 889 | } |
| | 890 | |
| | 891 | if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) { |
| | 892 | *size += opt_size; |
| | 893 | remaining -= opt_size; |
| | 894 | ret = true; |
| | 895 | } |
| | 896 | |
| | 897 | return ret; |
| | 898 | } |
| | 899 | |
| | 900 | bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, |
| | 901 | struct mptcp_out_options *opts) |
| | 902 | { |
| | 903 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| | 904 | |
| | 905 | if (subflow_req->mp_capable) { |
| | 906 | opts->suboptions = OPTION_MPTCP_MPC_SYNACK; |
| | 907 | opts->sndr_key = subflow_req->local_key; |
| | 908 | opts->csum_reqd = subflow_req->csum_reqd; |
| | 909 | opts->allow_join_id0 = subflow_req->allow_join_id0; |
| | 910 | *size = TCPOLEN_MPTCP_MPC_SYNACK; |
| | 911 | pr_debug("subflow_req=%p, local_key=%llu\n", |
| | 912 | subflow_req, subflow_req->local_key); |
| | 913 | return true; |
| | 914 | } else if (subflow_req->mp_join) { |
| | 915 | opts->suboptions = OPTION_MPTCP_MPJ_SYNACK; |
| | 916 | opts->backup = subflow_req->request_bkup; |
| | 917 | opts->join_id = subflow_req->local_id; |
| | 918 | opts->thmac = subflow_req->thmac; |
| | 919 | opts->nonce = subflow_req->local_nonce; |
| | 920 | pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u\n", |
| | 921 | subflow_req, opts->backup, opts->join_id, |
| | 922 | opts->thmac, opts->nonce); |
| | 923 | *size = TCPOLEN_MPTCP_MPJ_SYNACK; |
| | 924 | return true; |
| | 925 | } |
| | 926 | return false; |
| | 927 | } |
| | 928 | |
| | 929 | static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk, |
| | 930 | struct mptcp_subflow_context *subflow, |
| | 931 | struct sk_buff *skb, |
| | 932 | struct mptcp_options_received *mp_opt) |
| | 933 | { |
| | 934 | /* here we can process OoO, in-window pkts, only in-sequence 4th ack |
| | 935 | * will make the subflow fully established |
| | 936 | */ |
| | 937 | if (likely(READ_ONCE(subflow->fully_established))) { |
| | 938 | /* on passive sockets, check for 3rd ack retransmission |
| | 939 | * note that msk is always set by subflow_syn_recv_sock() |
| | 940 | * for mp_join subflows |
| | 941 | */ |
| | 942 | if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 && |
| | 943 | TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq && |
| | 944 | subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) && |
| | 945 | !subflow->request_join) |
| | 946 | tcp_send_ack(ssk); |
| | 947 | goto check_notify; |
| | 948 | } |
| | 949 | |
| | 950 | /* we must process OoO packets before the first subflow is fully |
| | 951 | * established. OoO packets are instead a protocol violation |
| | 952 | * for MP_JOIN subflows as the peer must not send any data |
| | 953 | * before receiving the forth ack - cfr. RFC 8684 section 3.2. |
| | 954 | */ |
| | 955 | if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) { |
| | 956 | if (subflow->mp_join) |
| | 957 | goto reset; |
| | 958 | if (subflow->is_mptfo && mp_opt->suboptions & OPTION_MPTCP_MPC_ACK) |
| | 959 | goto set_fully_established; |
| | 960 | return subflow->mp_capable; |
| | 961 | } |
| | 962 | |
| | 963 | if (subflow->remote_key_valid && |
| | 964 | (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) || |
| | 965 | ((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && |
| | 966 | (!mp_opt->echo || subflow->mp_join)))) { |
| | 967 | /* subflows are fully established as soon as we get any |
| | 968 | * additional ack, including ADD_ADDR. |
| | 969 | */ |
| | 970 | goto set_fully_established; |
| | 971 | } |
| | 972 | |
| | 973 | /* If the first established packet does not contain MP_CAPABLE + data |
| | 974 | * then fallback to TCP. Fallback scenarios requires a reset for |
| | 975 | * MP_JOIN subflows. |
| | 976 | */ |
| | 977 | if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) { |
| | 978 | if (subflow->mp_join) |
| | 979 | goto reset; |
| | 980 | subflow->mp_capable = 0; |
| | 981 | pr_fallback(msk); |
| | 982 | mptcp_do_fallback(ssk); |
| | 983 | return false; |
| | 984 | } |
| | 985 | |
| | 986 | if (mp_opt->deny_join_id0) |
| | 987 | WRITE_ONCE(msk->pm.remote_deny_join_id0, true); |
| | 988 | |
| | 989 | if (unlikely(!READ_ONCE(msk->pm.server_side))) |
| | 990 | pr_warn_once("bogus mpc option on established client sk"); |
| | 991 | |
| | 992 | set_fully_established: |
| | 993 | mptcp_data_lock((struct sock *)msk); |
| | 994 | __mptcp_subflow_fully_established(msk, subflow, mp_opt); |
| | 995 | mptcp_data_unlock((struct sock *)msk); |
| | 996 | |
| | 997 | check_notify: |
| | 998 | /* if the subflow is not already linked into the conn_list, we can't |
| | 999 | * notify the PM: this subflow is still on the listener queue |
| | 1000 | * and the PM possibly acquiring the subflow lock could race with |
| | 1001 | * the listener close |
| | 1002 | */ |
| | 1003 | if (likely(subflow->pm_notified) || list_empty(&subflow->node)) |
| | 1004 | return true; |
| | 1005 | |
| | 1006 | subflow->pm_notified = 1; |
| | 1007 | if (subflow->mp_join) { |
| | 1008 | clear_3rdack_retransmission(ssk); |
| | 1009 | mptcp_pm_subflow_established(msk); |
| | 1010 | } else { |
| | 1011 | mptcp_pm_fully_established(msk, ssk); |
| | 1012 | } |
| | 1013 | return true; |
| | 1014 | |
| | 1015 | reset: |
| | 1016 | mptcp_subflow_reset(ssk); |
| | 1017 | return false; |
| | 1018 | } |
| | 1019 | |
| | 1020 | u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq) |
| | 1021 | { |
| | 1022 | u32 old_seq32, cur_seq32; |
| | 1023 | |
| | 1024 | old_seq32 = (u32)old_seq; |
| | 1025 | cur_seq32 = (u32)cur_seq; |
| | 1026 | cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32; |
| | 1027 | if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32))) |
| | 1028 | return cur_seq + (1LL << 32); |
| | 1029 | |
| | 1030 | /* reverse wrap could happen, too */ |
| | 1031 | if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32))) |
| | 1032 | return cur_seq - (1LL << 32); |
| | 1033 | return cur_seq; |
| | 1034 | } |
| | 1035 | |
| | 1036 | static void __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una) |
| | 1037 | { |
| | 1038 | msk->bytes_acked += new_snd_una - msk->snd_una; |
| | 1039 | WRITE_ONCE(msk->snd_una, new_snd_una); |
| | 1040 | } |
| | 1041 | |
| | 1042 | static void ack_update_msk(struct mptcp_sock *msk, |
| | 1043 | struct sock *ssk, |
| | 1044 | struct mptcp_options_received *mp_opt) |
| | 1045 | { |
| | 1046 | u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt); |
| | 1047 | struct sock *sk = (struct sock *)msk; |
| | 1048 | u64 old_snd_una; |
| | 1049 | |
| | 1050 | mptcp_data_lock(sk); |
| | 1051 | |
| | 1052 | /* avoid ack expansion on update conflict, to reduce the risk of |
| | 1053 | * wrongly expanding to a future ack sequence number, which is way |
| | 1054 | * more dangerous than missing an ack |
| | 1055 | */ |
| | 1056 | old_snd_una = msk->snd_una; |
| | 1057 | new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64); |
| | 1058 | |
| | 1059 | /* ACK for data not even sent yet? Ignore.*/ |
| | 1060 | if (unlikely(after64(new_snd_una, snd_nxt))) |
| | 1061 | new_snd_una = old_snd_una; |
| | 1062 | |
| | 1063 | new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd; |
| | 1064 | |
| | 1065 | if (after64(new_wnd_end, msk->wnd_end)) |
| | 1066 | WRITE_ONCE(msk->wnd_end, new_wnd_end); |
| | 1067 | |
| | 1068 | /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ |
| | 1069 | if (after64(msk->wnd_end, snd_nxt)) |
| | 1070 | __mptcp_check_push(sk, ssk); |
| | 1071 | |
| | 1072 | if (after64(new_snd_una, old_snd_una)) { |
| | 1073 | __mptcp_snd_una_update(msk, new_snd_una); |
| | 1074 | __mptcp_data_acked(sk); |
| | 1075 | } |
| | 1076 | msk->last_ack_recv = tcp_jiffies32; |
| | 1077 | mptcp_data_unlock(sk); |
| | 1078 | |
| | 1079 | trace_ack_update_msk(mp_opt->data_ack, |
| | 1080 | old_snd_una, new_snd_una, |
| | 1081 | new_wnd_end, READ_ONCE(msk->wnd_end)); |
| | 1082 | } |
| | 1083 | |
| | 1084 | bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit) |
| | 1085 | { |
| | 1086 | /* Skip if DATA_FIN was already received. |
| | 1087 | * If updating simultaneously with the recvmsg loop, values |
| | 1088 | * should match. If they mismatch, the peer is misbehaving and |
| | 1089 | * we will prefer the most recent information. |
| | 1090 | */ |
| | 1091 | if (READ_ONCE(msk->rcv_data_fin)) |
| | 1092 | return false; |
| | 1093 | |
| | 1094 | WRITE_ONCE(msk->rcv_data_fin_seq, |
| | 1095 | mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit)); |
| | 1096 | WRITE_ONCE(msk->rcv_data_fin, 1); |
| | 1097 | |
| | 1098 | return true; |
| | 1099 | } |
| | 1100 | |
| | 1101 | static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
| | 1102 | struct mptcp_options_received *mp_opt) |
| | 1103 | { |
| | 1104 | u64 hmac = 0; |
| | 1105 | |
| | 1106 | if (mp_opt->echo) |
| | 1107 | return true; |
| | 1108 | |
| | 1109 | hmac = add_addr_generate_hmac(READ_ONCE(msk->remote_key), |
| | 1110 | READ_ONCE(msk->local_key), |
| | 1111 | &mp_opt->addr); |
| | 1112 | |
| | 1113 | pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n", |
| | 1114 | msk, hmac, mp_opt->ahmac); |
| | 1115 | |
| | 1116 | return hmac == mp_opt->ahmac; |
| | 1117 | } |
| | 1118 | |
| | 1119 | /* Return false if a subflow has been reset, else return true */ |
| | 1120 | bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb) |
| | 1121 | { |
| | 1122 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| | 1123 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| | 1124 | struct mptcp_options_received mp_opt; |
| | 1125 | struct mptcp_ext *mpext; |
| | 1126 | |
| | 1127 | if (__mptcp_check_fallback(msk)) { |
| | 1128 | /* Keep it simple and unconditionally trigger send data cleanup and |
| | 1129 | * pending queue spooling. We will need to acquire the data lock |
| | 1130 | * for more accurate checks, and once the lock is acquired, such |
| | 1131 | * helpers are cheap. |
| | 1132 | */ |
| | 1133 | mptcp_data_lock(subflow->conn); |
| | 1134 | if (sk_stream_memory_free(sk)) |
| | 1135 | __mptcp_check_push(subflow->conn, sk); |
| | 1136 | |
| | 1137 | /* on fallback we just need to ignore the msk-level snd_una, as |
| | 1138 | * this is really plain TCP |
| | 1139 | */ |
| | 1140 | __mptcp_snd_una_update(msk, READ_ONCE(msk->snd_nxt)); |
| | 1141 | |
| | 1142 | __mptcp_data_acked(subflow->conn); |
| | 1143 | mptcp_data_unlock(subflow->conn); |
| | 1144 | return true; |
| | 1145 | } |
| | 1146 | |
| | 1147 | mptcp_get_options(skb, &mp_opt); |
| | 1148 | |
| | 1149 | /* The subflow can be in close state only if check_fully_established() |
| | 1150 | * just sent a reset. If so, tell the caller to ignore the current packet. |
| | 1151 | */ |
| | 1152 | if (!check_fully_established(msk, sk, subflow, skb, &mp_opt)) |
| | 1153 | return sk->sk_state != TCP_CLOSE; |
| | 1154 | |
| | 1155 | if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) { |
| | 1156 | if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) && |
| | 1157 | READ_ONCE(msk->local_key) == mp_opt.rcvr_key) { |
| | 1158 | WRITE_ONCE(msk->rcv_fastclose, true); |
| | 1159 | mptcp_schedule_work((struct sock *)msk); |
| | 1160 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSERX); |
| | 1161 | } |
| | 1162 | |
| | 1163 | if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) && |
| | 1164 | add_addr_hmac_valid(msk, &mp_opt)) { |
| | 1165 | if (!mp_opt.echo) { |
| | 1166 | mptcp_pm_add_addr_received(sk, &mp_opt.addr); |
| | 1167 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR); |
| | 1168 | } else { |
| | 1169 | mptcp_pm_add_addr_echoed(msk, &mp_opt.addr); |
| | 1170 | mptcp_pm_del_add_timer(msk, &mp_opt.addr, true); |
| | 1171 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD); |
| | 1172 | } |
| | 1173 | |
| | 1174 | if (mp_opt.addr.port) |
| | 1175 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD); |
| | 1176 | } |
| | 1177 | |
| | 1178 | if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR) |
| | 1179 | mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list); |
| | 1180 | |
| | 1181 | if (mp_opt.suboptions & OPTION_MPTCP_PRIO) { |
| | 1182 | mptcp_pm_mp_prio_received(sk, mp_opt.backup); |
| | 1183 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX); |
| | 1184 | } |
| | 1185 | |
| | 1186 | if (mp_opt.suboptions & OPTION_MPTCP_FAIL) { |
| | 1187 | mptcp_pm_mp_fail_received(sk, mp_opt.fail_seq); |
| | 1188 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILRX); |
| | 1189 | } |
| | 1190 | |
| | 1191 | if (mp_opt.suboptions & OPTION_MPTCP_RST) { |
| | 1192 | subflow->reset_seen = 1; |
| | 1193 | subflow->reset_reason = mp_opt.reset_reason; |
| | 1194 | subflow->reset_transient = mp_opt.reset_transient; |
| | 1195 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTRX); |
| | 1196 | } |
| | 1197 | |
| | 1198 | if (!(mp_opt.suboptions & OPTION_MPTCP_DSS)) |
| | 1199 | return true; |
| | 1200 | } |
| | 1201 | |
| | 1202 | /* we can't wait for recvmsg() to update the ack_seq, otherwise |
| | 1203 | * monodirectional flows will stuck |
| | 1204 | */ |
| | 1205 | if (mp_opt.use_ack) |
| | 1206 | ack_update_msk(msk, sk, &mp_opt); |
| | 1207 | |
| | 1208 | /* Zero-data-length packets are dropped by the caller and not |
| | 1209 | * propagated to the MPTCP layer, so the skb extension does not |
| | 1210 | * need to be allocated or populated. DATA_FIN information, if |
| | 1211 | * present, needs to be updated here before the skb is freed. |
| | 1212 | */ |
| | 1213 | if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) { |
| | 1214 | if (mp_opt.data_fin && mp_opt.data_len == 1 && |
| | 1215 | mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64)) |
| | 1216 | mptcp_schedule_work((struct sock *)msk); |
| | 1217 | |
| | 1218 | return true; |
| | 1219 | } |
| | 1220 | |
| | 1221 | mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
| | 1222 | if (!mpext) |
| | 1223 | return true; |
| | 1224 | |
| | 1225 | memset(mpext, 0, sizeof(*mpext)); |
| | 1226 | |
| | 1227 | if (likely(mp_opt.use_map)) { |
| | 1228 | if (mp_opt.mpc_map) { |
| | 1229 | /* this is an MP_CAPABLE carrying MPTCP data |
| | 1230 | * we know this map the first chunk of data |
| | 1231 | */ |
| | 1232 | mptcp_crypto_key_sha(subflow->remote_key, NULL, |
| | 1233 | &mpext->data_seq); |
| | 1234 | mpext->data_seq++; |
| | 1235 | mpext->subflow_seq = 1; |
| | 1236 | mpext->dsn64 = 1; |
| | 1237 | mpext->mpc_map = 1; |
| | 1238 | mpext->data_fin = 0; |
| | 1239 | } else { |
| | 1240 | mpext->data_seq = mp_opt.data_seq; |
| | 1241 | mpext->subflow_seq = mp_opt.subflow_seq; |
| | 1242 | mpext->dsn64 = mp_opt.dsn64; |
| | 1243 | mpext->data_fin = mp_opt.data_fin; |
| | 1244 | } |
| | 1245 | mpext->data_len = mp_opt.data_len; |
| | 1246 | mpext->use_map = 1; |
| | 1247 | mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD); |
| | 1248 | |
| | 1249 | if (mpext->csum_reqd) |
| | 1250 | mpext->csum = mp_opt.csum; |
| | 1251 | } |
| | 1252 | |
| | 1253 | return true; |
| | 1254 | } |
| | 1255 | |
| | 1256 | static void mptcp_set_rwin(struct tcp_sock *tp, struct tcphdr *th) |
| | 1257 | { |
| | 1258 | const struct sock *ssk = (const struct sock *)tp; |
| | 1259 | struct mptcp_subflow_context *subflow; |
| | 1260 | u64 ack_seq, rcv_wnd_old, rcv_wnd_new; |
| | 1261 | struct mptcp_sock *msk; |
| | 1262 | u32 new_win; |
| | 1263 | u64 win; |
| | 1264 | |
| | 1265 | subflow = mptcp_subflow_ctx(ssk); |
| | 1266 | msk = mptcp_sk(subflow->conn); |
| | 1267 | |
| | 1268 | ack_seq = READ_ONCE(msk->ack_seq); |
| | 1269 | rcv_wnd_new = ack_seq + tp->rcv_wnd; |
| | 1270 | |
| | 1271 | rcv_wnd_old = atomic64_read(&msk->rcv_wnd_sent); |
| | 1272 | if (after64(rcv_wnd_new, rcv_wnd_old)) { |
| | 1273 | u64 rcv_wnd; |
| | 1274 | |
| | 1275 | for (;;) { |
| | 1276 | rcv_wnd = atomic64_cmpxchg(&msk->rcv_wnd_sent, rcv_wnd_old, rcv_wnd_new); |
| | 1277 | |
| | 1278 | if (rcv_wnd == rcv_wnd_old) |
| | 1279 | break; |
| | 1280 | |
| | 1281 | rcv_wnd_old = rcv_wnd; |
| | 1282 | if (before64(rcv_wnd_new, rcv_wnd_old)) { |
| | 1283 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE); |
| | 1284 | goto raise_win; |
| | 1285 | } |
| | 1286 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT); |
| | 1287 | } |
| | 1288 | goto update_wspace; |
| | 1289 | } |
| | 1290 | |
| | 1291 | if (rcv_wnd_new != rcv_wnd_old) { |
| | 1292 | raise_win: |
| | 1293 | win = rcv_wnd_old - ack_seq; |
| | 1294 | tp->rcv_wnd = min_t(u64, win, U32_MAX); |
| | 1295 | new_win = tp->rcv_wnd; |
| | 1296 | |
| | 1297 | /* Make sure we do not exceed the maximum possible |
| | 1298 | * scaled window. |
| | 1299 | */ |
| | 1300 | if (unlikely(th->syn)) |
| | 1301 | new_win = min(new_win, 65535U) << tp->rx_opt.rcv_wscale; |
| | 1302 | if (!tp->rx_opt.rcv_wscale && |
| | 1303 | READ_ONCE(sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows)) |
| | 1304 | new_win = min(new_win, MAX_TCP_WINDOW); |
| | 1305 | else |
| | 1306 | new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale)); |
| | 1307 | |
| | 1308 | /* RFC1323 scaling applied */ |
| | 1309 | new_win >>= tp->rx_opt.rcv_wscale; |
| | 1310 | th->window = htons(new_win); |
| | 1311 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDSHARED); |
| | 1312 | } |
| | 1313 | |
| | 1314 | update_wspace: |
| | 1315 | WRITE_ONCE(msk->old_wspace, tp->rcv_wnd); |
| | 1316 | } |
| | 1317 | |
| | 1318 | __sum16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum) |
| | 1319 | { |
| | 1320 | struct csum_pseudo_header header; |
| | 1321 | __wsum csum; |
| | 1322 | |
| | 1323 | /* cfr RFC 8684 3.3.1.: |
| | 1324 | * the data sequence number used in the pseudo-header is |
| | 1325 | * always the 64-bit value, irrespective of what length is used in the |
| | 1326 | * DSS option itself. |
| | 1327 | */ |
| | 1328 | header.data_seq = cpu_to_be64(data_seq); |
| | 1329 | header.subflow_seq = htonl(subflow_seq); |
| | 1330 | header.data_len = htons(data_len); |
| | 1331 | header.csum = 0; |
| | 1332 | |
| | 1333 | csum = csum_partial(&header, sizeof(header), sum); |
| | 1334 | return csum_fold(csum); |
| | 1335 | } |
| | 1336 | |
| | 1337 | static __sum16 mptcp_make_csum(const struct mptcp_ext *mpext) |
| | 1338 | { |
| | 1339 | return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len, |
| | 1340 | ~csum_unfold(mpext->csum)); |
| | 1341 | } |
| | 1342 | |
| | 1343 | static void put_len_csum(u16 len, __sum16 csum, void *data) |
| | 1344 | { |
| | 1345 | __sum16 *sumptr = data + 2; |
| | 1346 | __be16 *ptr = data; |
| | 1347 | |
| | 1348 | put_unaligned_be16(len, ptr); |
| | 1349 | |
| | 1350 | put_unaligned(csum, sumptr); |
| | 1351 | } |
| | 1352 | |
| | 1353 | void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp, |
| | 1354 | struct mptcp_out_options *opts) |
| | 1355 | { |
| | 1356 | const struct sock *ssk = (const struct sock *)tp; |
| | 1357 | struct mptcp_subflow_context *subflow; |
| | 1358 | |
| | 1359 | /* Which options can be used together? |
| | 1360 | * |
| | 1361 | * X: mutually exclusive |
| | 1362 | * O: often used together |
| | 1363 | * C: can be used together in some cases |
| | 1364 | * P: could be used together but we prefer not to (optimisations) |
| | 1365 | * |
| | 1366 | * Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC | |
| | 1367 | * ------|------|------|------|------|------|------|------|------| |
| | 1368 | * MPC |------|------|------|------|------|------|------|------| |
| | 1369 | * MPJ | X |------|------|------|------|------|------|------| |
| | 1370 | * DSS | X | X |------|------|------|------|------|------| |
| | 1371 | * ADD | X | X | P |------|------|------|------|------| |
| | 1372 | * RM | C | C | C | P |------|------|------|------| |
| | 1373 | * PRIO | X | C | C | C | C |------|------|------| |
| | 1374 | * FAIL | X | X | C | X | X | X |------|------| |
| | 1375 | * FC | X | X | X | X | X | X | X |------| |
| | 1376 | * RST | X | X | X | X | X | X | O | O | |
| | 1377 | * ------|------|------|------|------|------|------|------|------| |
| | 1378 | * |
| | 1379 | * The same applies in mptcp_established_options() function. |
| | 1380 | */ |
| | 1381 | if (likely(OPTION_MPTCP_DSS & opts->suboptions)) { |
| | 1382 | struct mptcp_ext *mpext = &opts->ext_copy; |
| | 1383 | u8 len = TCPOLEN_MPTCP_DSS_BASE; |
| | 1384 | u8 flags = 0; |
| | 1385 | |
| | 1386 | if (mpext->use_ack) { |
| | 1387 | flags = MPTCP_DSS_HAS_ACK; |
| | 1388 | if (mpext->ack64) { |
| | 1389 | len += TCPOLEN_MPTCP_DSS_ACK64; |
| | 1390 | flags |= MPTCP_DSS_ACK64; |
| | 1391 | } else { |
| | 1392 | len += TCPOLEN_MPTCP_DSS_ACK32; |
| | 1393 | } |
| | 1394 | } |
| | 1395 | |
| | 1396 | if (mpext->use_map) { |
| | 1397 | len += TCPOLEN_MPTCP_DSS_MAP64; |
| | 1398 | |
| | 1399 | /* Use only 64-bit mapping flags for now, add |
| | 1400 | * support for optional 32-bit mappings later. |
| | 1401 | */ |
| | 1402 | flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64; |
| | 1403 | if (mpext->data_fin) |
| | 1404 | flags |= MPTCP_DSS_DATA_FIN; |
| | 1405 | |
| | 1406 | if (opts->csum_reqd) |
| | 1407 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
| | 1408 | } |
| | 1409 | |
| | 1410 | *ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags); |
| | 1411 | |
| | 1412 | if (mpext->use_ack) { |
| | 1413 | if (mpext->ack64) { |
| | 1414 | put_unaligned_be64(mpext->data_ack, ptr); |
| | 1415 | ptr += 2; |
| | 1416 | } else { |
| | 1417 | put_unaligned_be32(mpext->data_ack32, ptr); |
| | 1418 | ptr += 1; |
| | 1419 | } |
| | 1420 | } |
| | 1421 | |
| | 1422 | if (mpext->use_map) { |
| | 1423 | put_unaligned_be64(mpext->data_seq, ptr); |
| | 1424 | ptr += 2; |
| | 1425 | put_unaligned_be32(mpext->subflow_seq, ptr); |
| | 1426 | ptr += 1; |
| | 1427 | if (opts->csum_reqd) { |
| | 1428 | /* data_len == 0 is reserved for the infinite mapping, |
| | 1429 | * the checksum will also be set to 0. |
| | 1430 | */ |
| | 1431 | put_len_csum(mpext->data_len, |
| | 1432 | (mpext->data_len ? mptcp_make_csum(mpext) : 0), |
| | 1433 | ptr); |
| | 1434 | } else { |
| | 1435 | put_unaligned_be32(mpext->data_len << 16 | |
| | 1436 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); |
| | 1437 | } |
| | 1438 | ptr += 1; |
| | 1439 | } |
| | 1440 | |
| | 1441 | /* We might need to add MP_FAIL options in rare cases */ |
| | 1442 | if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) |
| | 1443 | goto mp_fail; |
| | 1444 | } else if (OPTIONS_MPTCP_MPC & opts->suboptions) { |
| | 1445 | u8 len, flag = MPTCP_CAP_HMAC_SHA256; |
| | 1446 | |
| | 1447 | if (OPTION_MPTCP_MPC_SYN & opts->suboptions) { |
| | 1448 | len = TCPOLEN_MPTCP_MPC_SYN; |
| | 1449 | } else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) { |
| | 1450 | len = TCPOLEN_MPTCP_MPC_SYNACK; |
| | 1451 | } else if (opts->data_len) { |
| | 1452 | len = TCPOLEN_MPTCP_MPC_ACK_DATA; |
| | 1453 | if (opts->csum_reqd) |
| | 1454 | len += TCPOLEN_MPTCP_DSS_CHECKSUM; |
| | 1455 | } else { |
| | 1456 | len = TCPOLEN_MPTCP_MPC_ACK; |
| | 1457 | } |
| | 1458 | |
| | 1459 | if (opts->csum_reqd) |
| | 1460 | flag |= MPTCP_CAP_CHECKSUM_REQD; |
| | 1461 | |
| | 1462 | if (!opts->allow_join_id0) |
| | 1463 | flag |= MPTCP_CAP_DENY_JOIN_ID0; |
| | 1464 | |
| | 1465 | *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len, |
| | 1466 | MPTCP_SUPPORTED_VERSION, |
| | 1467 | flag); |
| | 1468 | |
| | 1469 | if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) & |
| | 1470 | opts->suboptions)) |
| | 1471 | goto mp_capable_done; |
| | 1472 | |
| | 1473 | put_unaligned_be64(opts->sndr_key, ptr); |
| | 1474 | ptr += 2; |
| | 1475 | if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions)) |
| | 1476 | goto mp_capable_done; |
| | 1477 | |
| | 1478 | put_unaligned_be64(opts->rcvr_key, ptr); |
| | 1479 | ptr += 2; |
| | 1480 | if (!opts->data_len) |
| | 1481 | goto mp_capable_done; |
| | 1482 | |
| | 1483 | if (opts->csum_reqd) { |
| | 1484 | put_len_csum(opts->data_len, |
| | 1485 | __mptcp_make_csum(opts->data_seq, |
| | 1486 | opts->subflow_seq, |
| | 1487 | opts->data_len, |
| | 1488 | ~csum_unfold(opts->csum)), |
| | 1489 | ptr); |
| | 1490 | } else { |
| | 1491 | put_unaligned_be32(opts->data_len << 16 | |
| | 1492 | TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); |
| | 1493 | } |
| | 1494 | ptr += 1; |
| | 1495 | |
| | 1496 | /* MPC is additionally mutually exclusive with MP_PRIO */ |
| | 1497 | goto mp_capable_done; |
| | 1498 | } else if (OPTIONS_MPTCP_MPJ & opts->suboptions) { |
| | 1499 | if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) { |
| | 1500 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
| | 1501 | TCPOLEN_MPTCP_MPJ_SYN, |
| | 1502 | opts->backup, opts->join_id); |
| | 1503 | put_unaligned_be32(opts->token, ptr); |
| | 1504 | ptr += 1; |
| | 1505 | put_unaligned_be32(opts->nonce, ptr); |
| | 1506 | ptr += 1; |
| | 1507 | } else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) { |
| | 1508 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
| | 1509 | TCPOLEN_MPTCP_MPJ_SYNACK, |
| | 1510 | opts->backup, opts->join_id); |
| | 1511 | put_unaligned_be64(opts->thmac, ptr); |
| | 1512 | ptr += 2; |
| | 1513 | put_unaligned_be32(opts->nonce, ptr); |
| | 1514 | ptr += 1; |
| | 1515 | } else { |
| | 1516 | *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN, |
| | 1517 | TCPOLEN_MPTCP_MPJ_ACK, 0, 0); |
| | 1518 | memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN); |
| | 1519 | ptr += 5; |
| | 1520 | } |
| | 1521 | } else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) { |
| | 1522 | u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE; |
| | 1523 | u8 echo = MPTCP_ADDR_ECHO; |
| | 1524 | |
| | 1525 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 1526 | if (opts->addr.family == AF_INET6) |
| | 1527 | len = TCPOLEN_MPTCP_ADD_ADDR6_BASE; |
| | 1528 | #endif |
| | 1529 | |
| | 1530 | if (opts->addr.port) |
| | 1531 | len += TCPOLEN_MPTCP_PORT_LEN; |
| | 1532 | |
| | 1533 | if (opts->ahmac) { |
| | 1534 | len += sizeof(opts->ahmac); |
| | 1535 | echo = 0; |
| | 1536 | } |
| | 1537 | |
| | 1538 | *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR, |
| | 1539 | len, echo, opts->addr.id); |
| | 1540 | if (opts->addr.family == AF_INET) { |
| | 1541 | memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4); |
| | 1542 | ptr += 1; |
| | 1543 | } |
| | 1544 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| | 1545 | else if (opts->addr.family == AF_INET6) { |
| | 1546 | memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16); |
| | 1547 | ptr += 4; |
| | 1548 | } |
| | 1549 | #endif |
| | 1550 | |
| | 1551 | if (!opts->addr.port) { |
| | 1552 | if (opts->ahmac) { |
| | 1553 | put_unaligned_be64(opts->ahmac, ptr); |
| | 1554 | ptr += 2; |
| | 1555 | } |
| | 1556 | } else { |
| | 1557 | u16 port = ntohs(opts->addr.port); |
| | 1558 | |
| | 1559 | if (opts->ahmac) { |
| | 1560 | u8 *bptr = (u8 *)ptr; |
| | 1561 | |
| | 1562 | put_unaligned_be16(port, bptr); |
| | 1563 | bptr += 2; |
| | 1564 | put_unaligned_be64(opts->ahmac, bptr); |
| | 1565 | bptr += 8; |
| | 1566 | put_unaligned_be16(TCPOPT_NOP << 8 | |
| | 1567 | TCPOPT_NOP, bptr); |
| | 1568 | |
| | 1569 | ptr += 3; |
| | 1570 | } else { |
| | 1571 | put_unaligned_be32(port << 16 | |
| | 1572 | TCPOPT_NOP << 8 | |
| | 1573 | TCPOPT_NOP, ptr); |
| | 1574 | ptr += 1; |
| | 1575 | } |
| | 1576 | } |
| | 1577 | } else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) { |
| | 1578 | /* FASTCLOSE is mutually exclusive with others except RST */ |
| | 1579 | *ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE, |
| | 1580 | TCPOLEN_MPTCP_FASTCLOSE, |
| | 1581 | 0, 0); |
| | 1582 | put_unaligned_be64(opts->rcvr_key, ptr); |
| | 1583 | ptr += 2; |
| | 1584 | |
| | 1585 | if (OPTION_MPTCP_RST & opts->suboptions) |
| | 1586 | goto mp_rst; |
| | 1587 | return; |
| | 1588 | } else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) { |
| | 1589 | mp_fail: |
| | 1590 | /* MP_FAIL is mutually exclusive with others except RST */ |
| | 1591 | subflow = mptcp_subflow_ctx(ssk); |
| | 1592 | subflow->send_mp_fail = 0; |
| | 1593 | |
| | 1594 | *ptr++ = mptcp_option(MPTCPOPT_MP_FAIL, |
| | 1595 | TCPOLEN_MPTCP_FAIL, |
| | 1596 | 0, 0); |
| | 1597 | put_unaligned_be64(opts->fail_seq, ptr); |
| | 1598 | ptr += 2; |
| | 1599 | |
| | 1600 | if (OPTION_MPTCP_RST & opts->suboptions) |
| | 1601 | goto mp_rst; |
| | 1602 | return; |
| | 1603 | } else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) { |
| | 1604 | mp_rst: |
| | 1605 | *ptr++ = mptcp_option(MPTCPOPT_RST, |
| | 1606 | TCPOLEN_MPTCP_RST, |
| | 1607 | opts->reset_transient, |
| | 1608 | opts->reset_reason); |
| | 1609 | return; |
| | 1610 | } |
| | 1611 | |
| | 1612 | if (OPTION_MPTCP_PRIO & opts->suboptions) { |
| | 1613 | subflow = mptcp_subflow_ctx(ssk); |
| | 1614 | subflow->send_mp_prio = 0; |
| | 1615 | |
| | 1616 | *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, |
| | 1617 | TCPOLEN_MPTCP_PRIO, |
| | 1618 | opts->backup, TCPOPT_NOP); |
| | 1619 | |
| | 1620 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPPRIOTX); |
| | 1621 | } |
| | 1622 | |
| | 1623 | mp_capable_done: |
| | 1624 | if (OPTION_MPTCP_RM_ADDR & opts->suboptions) { |
| | 1625 | u8 i = 1; |
| | 1626 | |
| | 1627 | *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR, |
| | 1628 | TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr, |
| | 1629 | 0, opts->rm_list.ids[0]); |
| | 1630 | |
| | 1631 | while (i < opts->rm_list.nr) { |
| | 1632 | u8 id1, id2, id3, id4; |
| | 1633 | |
| | 1634 | id1 = opts->rm_list.ids[i]; |
| | 1635 | id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP; |
| | 1636 | id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP; |
| | 1637 | id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP; |
| | 1638 | put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr); |
| | 1639 | ptr += 1; |
| | 1640 | i += 4; |
| | 1641 | } |
| | 1642 | } |
| | 1643 | |
| | 1644 | if (tp) |
| | 1645 | mptcp_set_rwin(tp, th); |
| | 1646 | } |
| | 1647 | |
| | 1648 | __be32 mptcp_get_reset_option(const struct sk_buff *skb) |
| | 1649 | { |
| | 1650 | const struct mptcp_ext *ext = mptcp_get_ext(skb); |
| | 1651 | u8 flags, reason; |
| | 1652 | |
| | 1653 | if (ext) { |
| | 1654 | flags = ext->reset_transient; |
| | 1655 | reason = ext->reset_reason; |
| | 1656 | |
| | 1657 | return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST, |
| | 1658 | flags, reason); |
| | 1659 | } |
| | 1660 | |
| | 1661 | return htonl(0u); |
| | 1662 | } |
| | 1663 | EXPORT_SYMBOL_GPL(mptcp_get_reset_option); |
projects / linux-block.git / blame_incremental