| 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 <linux/module.h> |
| 11 | #include <linux/netdevice.h> |
| 12 | #include <crypto/algapi.h> |
| 13 | #include <crypto/sha2.h> |
| 14 | #include <net/sock.h> |
| 15 | #include <net/inet_common.h> |
| 16 | #include <net/inet_hashtables.h> |
| 17 | #include <net/protocol.h> |
| 18 | #include <net/tcp.h> |
| 19 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 20 | #include <net/ip6_route.h> |
| 21 | #include <net/transp_v6.h> |
| 22 | #endif |
| 23 | #include <net/mptcp.h> |
| 24 | #include <uapi/linux/mptcp.h> |
| 25 | #include "protocol.h" |
| 26 | #include "mib.h" |
| 27 | |
| 28 | #include <trace/events/mptcp.h> |
| 29 | #include <trace/events/sock.h> |
| 30 | |
| 31 | static void mptcp_subflow_ops_undo_override(struct sock *ssk); |
| 32 | |
| 33 | static void SUBFLOW_REQ_INC_STATS(struct request_sock *req, |
| 34 | enum linux_mptcp_mib_field field) |
| 35 | { |
| 36 | MPTCP_INC_STATS(sock_net(req_to_sk(req)), field); |
| 37 | } |
| 38 | |
| 39 | static void subflow_req_destructor(struct request_sock *req) |
| 40 | { |
| 41 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 42 | |
| 43 | pr_debug("subflow_req=%p", subflow_req); |
| 44 | |
| 45 | if (subflow_req->msk) |
| 46 | sock_put((struct sock *)subflow_req->msk); |
| 47 | |
| 48 | mptcp_token_destroy_request(req); |
| 49 | } |
| 50 | |
| 51 | static void subflow_generate_hmac(u64 key1, u64 key2, u32 nonce1, u32 nonce2, |
| 52 | void *hmac) |
| 53 | { |
| 54 | u8 msg[8]; |
| 55 | |
| 56 | put_unaligned_be32(nonce1, &msg[0]); |
| 57 | put_unaligned_be32(nonce2, &msg[4]); |
| 58 | |
| 59 | mptcp_crypto_hmac_sha(key1, key2, msg, 8, hmac); |
| 60 | } |
| 61 | |
| 62 | static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk) |
| 63 | { |
| 64 | return mptcp_is_fully_established((void *)msk) && |
| 65 | ((mptcp_pm_is_userspace(msk) && |
| 66 | mptcp_userspace_pm_active(msk)) || |
| 67 | READ_ONCE(msk->pm.accept_subflow)); |
| 68 | } |
| 69 | |
| 70 | /* validate received token and create truncated hmac and nonce for SYN-ACK */ |
| 71 | static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req) |
| 72 | { |
| 73 | struct mptcp_sock *msk = subflow_req->msk; |
| 74 | u8 hmac[SHA256_DIGEST_SIZE]; |
| 75 | |
| 76 | get_random_bytes(&subflow_req->local_nonce, sizeof(u32)); |
| 77 | |
| 78 | subflow_generate_hmac(msk->local_key, msk->remote_key, |
| 79 | subflow_req->local_nonce, |
| 80 | subflow_req->remote_nonce, hmac); |
| 81 | |
| 82 | subflow_req->thmac = get_unaligned_be64(hmac); |
| 83 | } |
| 84 | |
| 85 | static struct mptcp_sock *subflow_token_join_request(struct request_sock *req) |
| 86 | { |
| 87 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 88 | struct mptcp_sock *msk; |
| 89 | int local_id; |
| 90 | |
| 91 | msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token); |
| 92 | if (!msk) { |
| 93 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN); |
| 94 | return NULL; |
| 95 | } |
| 96 | |
| 97 | local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req); |
| 98 | if (local_id < 0) { |
| 99 | sock_put((struct sock *)msk); |
| 100 | return NULL; |
| 101 | } |
| 102 | subflow_req->local_id = local_id; |
| 103 | |
| 104 | return msk; |
| 105 | } |
| 106 | |
| 107 | static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener) |
| 108 | { |
| 109 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 110 | |
| 111 | subflow_req->mp_capable = 0; |
| 112 | subflow_req->mp_join = 0; |
| 113 | subflow_req->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk_listener)); |
| 114 | subflow_req->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk_listener)); |
| 115 | subflow_req->msk = NULL; |
| 116 | mptcp_token_init_request(req); |
| 117 | } |
| 118 | |
| 119 | static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk) |
| 120 | { |
| 121 | return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport; |
| 122 | } |
| 123 | |
| 124 | static void subflow_add_reset_reason(struct sk_buff *skb, u8 reason) |
| 125 | { |
| 126 | struct mptcp_ext *mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
| 127 | |
| 128 | if (mpext) { |
| 129 | memset(mpext, 0, sizeof(*mpext)); |
| 130 | mpext->reset_reason = reason; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | /* Init mptcp request socket. |
| 135 | * |
| 136 | * Returns an error code if a JOIN has failed and a TCP reset |
| 137 | * should be sent. |
| 138 | */ |
| 139 | static int subflow_check_req(struct request_sock *req, |
| 140 | const struct sock *sk_listener, |
| 141 | struct sk_buff *skb) |
| 142 | { |
| 143 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); |
| 144 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 145 | struct mptcp_options_received mp_opt; |
| 146 | bool opt_mp_capable, opt_mp_join; |
| 147 | |
| 148 | pr_debug("subflow_req=%p, listener=%p", subflow_req, listener); |
| 149 | |
| 150 | #ifdef CONFIG_TCP_MD5SIG |
| 151 | /* no MPTCP if MD5SIG is enabled on this socket or we may run out of |
| 152 | * TCP option space. |
| 153 | */ |
| 154 | if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info)) |
| 155 | return -EINVAL; |
| 156 | #endif |
| 157 | |
| 158 | mptcp_get_options(skb, &mp_opt); |
| 159 | |
| 160 | opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC); |
| 161 | opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ); |
| 162 | if (opt_mp_capable) { |
| 163 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); |
| 164 | |
| 165 | if (opt_mp_join) |
| 166 | return 0; |
| 167 | } else if (opt_mp_join) { |
| 168 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX); |
| 169 | } |
| 170 | |
| 171 | if (opt_mp_capable && listener->request_mptcp) { |
| 172 | int err, retries = MPTCP_TOKEN_MAX_RETRIES; |
| 173 | |
| 174 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
| 175 | again: |
| 176 | do { |
| 177 | get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key)); |
| 178 | } while (subflow_req->local_key == 0); |
| 179 | |
| 180 | if (unlikely(req->syncookie)) { |
| 181 | mptcp_crypto_key_sha(subflow_req->local_key, |
| 182 | &subflow_req->token, |
| 183 | &subflow_req->idsn); |
| 184 | if (mptcp_token_exists(subflow_req->token)) { |
| 185 | if (retries-- > 0) |
| 186 | goto again; |
| 187 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); |
| 188 | } else { |
| 189 | subflow_req->mp_capable = 1; |
| 190 | } |
| 191 | return 0; |
| 192 | } |
| 193 | |
| 194 | err = mptcp_token_new_request(req); |
| 195 | if (err == 0) |
| 196 | subflow_req->mp_capable = 1; |
| 197 | else if (retries-- > 0) |
| 198 | goto again; |
| 199 | else |
| 200 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT); |
| 201 | |
| 202 | } else if (opt_mp_join && listener->request_mptcp) { |
| 203 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq; |
| 204 | subflow_req->mp_join = 1; |
| 205 | subflow_req->backup = mp_opt.backup; |
| 206 | subflow_req->remote_id = mp_opt.join_id; |
| 207 | subflow_req->token = mp_opt.token; |
| 208 | subflow_req->remote_nonce = mp_opt.nonce; |
| 209 | subflow_req->msk = subflow_token_join_request(req); |
| 210 | |
| 211 | /* Can't fall back to TCP in this case. */ |
| 212 | if (!subflow_req->msk) { |
| 213 | subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); |
| 214 | return -EPERM; |
| 215 | } |
| 216 | |
| 217 | if (subflow_use_different_sport(subflow_req->msk, sk_listener)) { |
| 218 | pr_debug("syn inet_sport=%d %d", |
| 219 | ntohs(inet_sk(sk_listener)->inet_sport), |
| 220 | ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport)); |
| 221 | if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) { |
| 222 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX); |
| 223 | return -EPERM; |
| 224 | } |
| 225 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX); |
| 226 | } |
| 227 | |
| 228 | subflow_req_create_thmac(subflow_req); |
| 229 | |
| 230 | if (unlikely(req->syncookie)) { |
| 231 | if (mptcp_can_accept_new_subflow(subflow_req->msk)) |
| 232 | subflow_init_req_cookie_join_save(subflow_req, skb); |
| 233 | else |
| 234 | return -EPERM; |
| 235 | } |
| 236 | |
| 237 | pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token, |
| 238 | subflow_req->remote_nonce, subflow_req->msk); |
| 239 | } |
| 240 | |
| 241 | return 0; |
| 242 | } |
| 243 | |
| 244 | int mptcp_subflow_init_cookie_req(struct request_sock *req, |
| 245 | const struct sock *sk_listener, |
| 246 | struct sk_buff *skb) |
| 247 | { |
| 248 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener); |
| 249 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 250 | struct mptcp_options_received mp_opt; |
| 251 | bool opt_mp_capable, opt_mp_join; |
| 252 | int err; |
| 253 | |
| 254 | subflow_init_req(req, sk_listener); |
| 255 | mptcp_get_options(skb, &mp_opt); |
| 256 | |
| 257 | opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC); |
| 258 | opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ); |
| 259 | if (opt_mp_capable && opt_mp_join) |
| 260 | return -EINVAL; |
| 261 | |
| 262 | if (opt_mp_capable && listener->request_mptcp) { |
| 263 | if (mp_opt.sndr_key == 0) |
| 264 | return -EINVAL; |
| 265 | |
| 266 | subflow_req->local_key = mp_opt.rcvr_key; |
| 267 | err = mptcp_token_new_request(req); |
| 268 | if (err) |
| 269 | return err; |
| 270 | |
| 271 | subflow_req->mp_capable = 1; |
| 272 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; |
| 273 | } else if (opt_mp_join && listener->request_mptcp) { |
| 274 | if (!mptcp_token_join_cookie_init_state(subflow_req, skb)) |
| 275 | return -EINVAL; |
| 276 | |
| 277 | subflow_req->mp_join = 1; |
| 278 | subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1; |
| 279 | } |
| 280 | |
| 281 | return 0; |
| 282 | } |
| 283 | EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req); |
| 284 | |
| 285 | static struct dst_entry *subflow_v4_route_req(const struct sock *sk, |
| 286 | struct sk_buff *skb, |
| 287 | struct flowi *fl, |
| 288 | struct request_sock *req) |
| 289 | { |
| 290 | struct dst_entry *dst; |
| 291 | int err; |
| 292 | |
| 293 | tcp_rsk(req)->is_mptcp = 1; |
| 294 | subflow_init_req(req, sk); |
| 295 | |
| 296 | dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req); |
| 297 | if (!dst) |
| 298 | return NULL; |
| 299 | |
| 300 | err = subflow_check_req(req, sk, skb); |
| 301 | if (err == 0) |
| 302 | return dst; |
| 303 | |
| 304 | dst_release(dst); |
| 305 | if (!req->syncookie) |
| 306 | tcp_request_sock_ops.send_reset(sk, skb); |
| 307 | return NULL; |
| 308 | } |
| 309 | |
| 310 | static void subflow_prep_synack(const struct sock *sk, struct request_sock *req, |
| 311 | struct tcp_fastopen_cookie *foc, |
| 312 | enum tcp_synack_type synack_type) |
| 313 | { |
| 314 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 315 | struct inet_request_sock *ireq = inet_rsk(req); |
| 316 | |
| 317 | /* clear tstamp_ok, as needed depending on cookie */ |
| 318 | if (foc && foc->len > -1) |
| 319 | ireq->tstamp_ok = 0; |
| 320 | |
| 321 | if (synack_type == TCP_SYNACK_FASTOPEN) |
| 322 | mptcp_fastopen_subflow_synack_set_params(subflow, req); |
| 323 | } |
| 324 | |
| 325 | static int subflow_v4_send_synack(const struct sock *sk, struct dst_entry *dst, |
| 326 | struct flowi *fl, |
| 327 | struct request_sock *req, |
| 328 | struct tcp_fastopen_cookie *foc, |
| 329 | enum tcp_synack_type synack_type, |
| 330 | struct sk_buff *syn_skb) |
| 331 | { |
| 332 | subflow_prep_synack(sk, req, foc, synack_type); |
| 333 | |
| 334 | return tcp_request_sock_ipv4_ops.send_synack(sk, dst, fl, req, foc, |
| 335 | synack_type, syn_skb); |
| 336 | } |
| 337 | |
| 338 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 339 | static int subflow_v6_send_synack(const struct sock *sk, struct dst_entry *dst, |
| 340 | struct flowi *fl, |
| 341 | struct request_sock *req, |
| 342 | struct tcp_fastopen_cookie *foc, |
| 343 | enum tcp_synack_type synack_type, |
| 344 | struct sk_buff *syn_skb) |
| 345 | { |
| 346 | subflow_prep_synack(sk, req, foc, synack_type); |
| 347 | |
| 348 | return tcp_request_sock_ipv6_ops.send_synack(sk, dst, fl, req, foc, |
| 349 | synack_type, syn_skb); |
| 350 | } |
| 351 | |
| 352 | static struct dst_entry *subflow_v6_route_req(const struct sock *sk, |
| 353 | struct sk_buff *skb, |
| 354 | struct flowi *fl, |
| 355 | struct request_sock *req) |
| 356 | { |
| 357 | struct dst_entry *dst; |
| 358 | int err; |
| 359 | |
| 360 | tcp_rsk(req)->is_mptcp = 1; |
| 361 | subflow_init_req(req, sk); |
| 362 | |
| 363 | dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req); |
| 364 | if (!dst) |
| 365 | return NULL; |
| 366 | |
| 367 | err = subflow_check_req(req, sk, skb); |
| 368 | if (err == 0) |
| 369 | return dst; |
| 370 | |
| 371 | dst_release(dst); |
| 372 | if (!req->syncookie) |
| 373 | tcp6_request_sock_ops.send_reset(sk, skb); |
| 374 | return NULL; |
| 375 | } |
| 376 | #endif |
| 377 | |
| 378 | /* validate received truncated hmac and create hmac for third ACK */ |
| 379 | static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow) |
| 380 | { |
| 381 | u8 hmac[SHA256_DIGEST_SIZE]; |
| 382 | u64 thmac; |
| 383 | |
| 384 | subflow_generate_hmac(subflow->remote_key, subflow->local_key, |
| 385 | subflow->remote_nonce, subflow->local_nonce, |
| 386 | hmac); |
| 387 | |
| 388 | thmac = get_unaligned_be64(hmac); |
| 389 | pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n", |
| 390 | subflow, subflow->token, thmac, subflow->thmac); |
| 391 | |
| 392 | return thmac == subflow->thmac; |
| 393 | } |
| 394 | |
| 395 | void mptcp_subflow_reset(struct sock *ssk) |
| 396 | { |
| 397 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 398 | struct sock *sk = subflow->conn; |
| 399 | |
| 400 | /* mptcp_mp_fail_no_response() can reach here on an already closed |
| 401 | * socket |
| 402 | */ |
| 403 | if (ssk->sk_state == TCP_CLOSE) |
| 404 | return; |
| 405 | |
| 406 | /* must hold: tcp_done() could drop last reference on parent */ |
| 407 | sock_hold(sk); |
| 408 | |
| 409 | tcp_send_active_reset(ssk, GFP_ATOMIC); |
| 410 | tcp_done(ssk); |
| 411 | if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags)) |
| 412 | mptcp_schedule_work(sk); |
| 413 | |
| 414 | sock_put(sk); |
| 415 | } |
| 416 | |
| 417 | static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk) |
| 418 | { |
| 419 | return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport; |
| 420 | } |
| 421 | |
| 422 | void __mptcp_set_connected(struct sock *sk) |
| 423 | { |
| 424 | if (sk->sk_state == TCP_SYN_SENT) { |
| 425 | inet_sk_state_store(sk, TCP_ESTABLISHED); |
| 426 | sk->sk_state_change(sk); |
| 427 | } |
| 428 | } |
| 429 | |
| 430 | static void mptcp_set_connected(struct sock *sk) |
| 431 | { |
| 432 | mptcp_data_lock(sk); |
| 433 | if (!sock_owned_by_user(sk)) |
| 434 | __mptcp_set_connected(sk); |
| 435 | else |
| 436 | __set_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->cb_flags); |
| 437 | mptcp_data_unlock(sk); |
| 438 | } |
| 439 | |
| 440 | static void subflow_set_remote_key(struct mptcp_sock *msk, |
| 441 | struct mptcp_subflow_context *subflow, |
| 442 | const struct mptcp_options_received *mp_opt) |
| 443 | { |
| 444 | /* active MPC subflow will reach here multiple times: |
| 445 | * at subflow_finish_connect() time and at 4th ack time |
| 446 | */ |
| 447 | if (subflow->remote_key_valid) |
| 448 | return; |
| 449 | |
| 450 | subflow->remote_key_valid = 1; |
| 451 | subflow->remote_key = mp_opt->sndr_key; |
| 452 | mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn); |
| 453 | subflow->iasn++; |
| 454 | |
| 455 | WRITE_ONCE(msk->remote_key, subflow->remote_key); |
| 456 | WRITE_ONCE(msk->ack_seq, subflow->iasn); |
| 457 | WRITE_ONCE(msk->can_ack, true); |
| 458 | atomic64_set(&msk->rcv_wnd_sent, subflow->iasn); |
| 459 | } |
| 460 | |
| 461 | static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) |
| 462 | { |
| 463 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 464 | struct mptcp_options_received mp_opt; |
| 465 | struct sock *parent = subflow->conn; |
| 466 | struct mptcp_sock *msk; |
| 467 | |
| 468 | subflow->icsk_af_ops->sk_rx_dst_set(sk, skb); |
| 469 | |
| 470 | /* be sure no special action on any packet other than syn-ack */ |
| 471 | if (subflow->conn_finished) |
| 472 | return; |
| 473 | |
| 474 | msk = mptcp_sk(parent); |
| 475 | mptcp_propagate_sndbuf(parent, sk); |
| 476 | subflow->rel_write_seq = 1; |
| 477 | subflow->conn_finished = 1; |
| 478 | subflow->ssn_offset = TCP_SKB_CB(skb)->seq; |
| 479 | pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset); |
| 480 | |
| 481 | mptcp_get_options(skb, &mp_opt); |
| 482 | if (subflow->request_mptcp) { |
| 483 | if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) { |
| 484 | MPTCP_INC_STATS(sock_net(sk), |
| 485 | MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); |
| 486 | mptcp_do_fallback(sk); |
| 487 | pr_fallback(msk); |
| 488 | goto fallback; |
| 489 | } |
| 490 | |
| 491 | if (mp_opt.suboptions & OPTION_MPTCP_CSUMREQD) |
| 492 | WRITE_ONCE(msk->csum_enabled, true); |
| 493 | if (mp_opt.deny_join_id0) |
| 494 | WRITE_ONCE(msk->pm.remote_deny_join_id0, true); |
| 495 | subflow->mp_capable = 1; |
| 496 | subflow_set_remote_key(msk, subflow, &mp_opt); |
| 497 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEACK); |
| 498 | mptcp_finish_connect(sk); |
| 499 | mptcp_set_connected(parent); |
| 500 | } else if (subflow->request_join) { |
| 501 | u8 hmac[SHA256_DIGEST_SIZE]; |
| 502 | |
| 503 | if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ)) { |
| 504 | subflow->reset_reason = MPTCP_RST_EMPTCP; |
| 505 | goto do_reset; |
| 506 | } |
| 507 | |
| 508 | subflow->backup = mp_opt.backup; |
| 509 | subflow->thmac = mp_opt.thmac; |
| 510 | subflow->remote_nonce = mp_opt.nonce; |
| 511 | subflow->remote_id = mp_opt.join_id; |
| 512 | pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u backup=%d", |
| 513 | subflow, subflow->thmac, subflow->remote_nonce, |
| 514 | subflow->backup); |
| 515 | |
| 516 | if (!subflow_thmac_valid(subflow)) { |
| 517 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC); |
| 518 | subflow->reset_reason = MPTCP_RST_EMPTCP; |
| 519 | goto do_reset; |
| 520 | } |
| 521 | |
| 522 | if (!mptcp_finish_join(sk)) |
| 523 | goto do_reset; |
| 524 | |
| 525 | subflow_generate_hmac(subflow->local_key, subflow->remote_key, |
| 526 | subflow->local_nonce, |
| 527 | subflow->remote_nonce, |
| 528 | hmac); |
| 529 | memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN); |
| 530 | |
| 531 | subflow->mp_join = 1; |
| 532 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX); |
| 533 | |
| 534 | if (subflow_use_different_dport(msk, sk)) { |
| 535 | pr_debug("synack inet_dport=%d %d", |
| 536 | ntohs(inet_sk(sk)->inet_dport), |
| 537 | ntohs(inet_sk(parent)->inet_dport)); |
| 538 | MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX); |
| 539 | } |
| 540 | } else if (mptcp_check_fallback(sk)) { |
| 541 | fallback: |
| 542 | mptcp_rcv_space_init(msk, sk); |
| 543 | mptcp_set_connected(parent); |
| 544 | } |
| 545 | return; |
| 546 | |
| 547 | do_reset: |
| 548 | subflow->reset_transient = 0; |
| 549 | mptcp_subflow_reset(sk); |
| 550 | } |
| 551 | |
| 552 | static void subflow_set_local_id(struct mptcp_subflow_context *subflow, int local_id) |
| 553 | { |
| 554 | subflow->local_id = local_id; |
| 555 | subflow->local_id_valid = 1; |
| 556 | } |
| 557 | |
| 558 | static int subflow_chk_local_id(struct sock *sk) |
| 559 | { |
| 560 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 561 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| 562 | int err; |
| 563 | |
| 564 | if (likely(subflow->local_id_valid)) |
| 565 | return 0; |
| 566 | |
| 567 | err = mptcp_pm_get_local_id(msk, (struct sock_common *)sk); |
| 568 | if (err < 0) |
| 569 | return err; |
| 570 | |
| 571 | subflow_set_local_id(subflow, err); |
| 572 | return 0; |
| 573 | } |
| 574 | |
| 575 | static int subflow_rebuild_header(struct sock *sk) |
| 576 | { |
| 577 | int err = subflow_chk_local_id(sk); |
| 578 | |
| 579 | if (unlikely(err < 0)) |
| 580 | return err; |
| 581 | |
| 582 | return inet_sk_rebuild_header(sk); |
| 583 | } |
| 584 | |
| 585 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 586 | static int subflow_v6_rebuild_header(struct sock *sk) |
| 587 | { |
| 588 | int err = subflow_chk_local_id(sk); |
| 589 | |
| 590 | if (unlikely(err < 0)) |
| 591 | return err; |
| 592 | |
| 593 | return inet6_sk_rebuild_header(sk); |
| 594 | } |
| 595 | #endif |
| 596 | |
| 597 | static struct request_sock_ops mptcp_subflow_v4_request_sock_ops __ro_after_init; |
| 598 | static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init; |
| 599 | |
| 600 | static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb) |
| 601 | { |
| 602 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 603 | |
| 604 | pr_debug("subflow=%p", subflow); |
| 605 | |
| 606 | /* Never answer to SYNs sent to broadcast or multicast */ |
| 607 | if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) |
| 608 | goto drop; |
| 609 | |
| 610 | return tcp_conn_request(&mptcp_subflow_v4_request_sock_ops, |
| 611 | &subflow_request_sock_ipv4_ops, |
| 612 | sk, skb); |
| 613 | drop: |
| 614 | tcp_listendrop(sk); |
| 615 | return 0; |
| 616 | } |
| 617 | |
| 618 | static void subflow_v4_req_destructor(struct request_sock *req) |
| 619 | { |
| 620 | subflow_req_destructor(req); |
| 621 | tcp_request_sock_ops.destructor(req); |
| 622 | } |
| 623 | |
| 624 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 625 | static struct request_sock_ops mptcp_subflow_v6_request_sock_ops __ro_after_init; |
| 626 | static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops __ro_after_init; |
| 627 | static struct inet_connection_sock_af_ops subflow_v6_specific __ro_after_init; |
| 628 | static struct inet_connection_sock_af_ops subflow_v6m_specific __ro_after_init; |
| 629 | static struct proto tcpv6_prot_override __ro_after_init; |
| 630 | |
| 631 | static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb) |
| 632 | { |
| 633 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 634 | |
| 635 | pr_debug("subflow=%p", subflow); |
| 636 | |
| 637 | if (skb->protocol == htons(ETH_P_IP)) |
| 638 | return subflow_v4_conn_request(sk, skb); |
| 639 | |
| 640 | if (!ipv6_unicast_destination(skb)) |
| 641 | goto drop; |
| 642 | |
| 643 | if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) { |
| 644 | __IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS); |
| 645 | return 0; |
| 646 | } |
| 647 | |
| 648 | return tcp_conn_request(&mptcp_subflow_v6_request_sock_ops, |
| 649 | &subflow_request_sock_ipv6_ops, sk, skb); |
| 650 | |
| 651 | drop: |
| 652 | tcp_listendrop(sk); |
| 653 | return 0; /* don't send reset */ |
| 654 | } |
| 655 | |
| 656 | static void subflow_v6_req_destructor(struct request_sock *req) |
| 657 | { |
| 658 | subflow_req_destructor(req); |
| 659 | tcp6_request_sock_ops.destructor(req); |
| 660 | } |
| 661 | #endif |
| 662 | |
| 663 | struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops, |
| 664 | struct sock *sk_listener, |
| 665 | bool attach_listener) |
| 666 | { |
| 667 | if (ops->family == AF_INET) |
| 668 | ops = &mptcp_subflow_v4_request_sock_ops; |
| 669 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 670 | else if (ops->family == AF_INET6) |
| 671 | ops = &mptcp_subflow_v6_request_sock_ops; |
| 672 | #endif |
| 673 | |
| 674 | return inet_reqsk_alloc(ops, sk_listener, attach_listener); |
| 675 | } |
| 676 | EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc); |
| 677 | |
| 678 | /* validate hmac received in third ACK */ |
| 679 | static bool subflow_hmac_valid(const struct request_sock *req, |
| 680 | const struct mptcp_options_received *mp_opt) |
| 681 | { |
| 682 | const struct mptcp_subflow_request_sock *subflow_req; |
| 683 | u8 hmac[SHA256_DIGEST_SIZE]; |
| 684 | struct mptcp_sock *msk; |
| 685 | |
| 686 | subflow_req = mptcp_subflow_rsk(req); |
| 687 | msk = subflow_req->msk; |
| 688 | if (!msk) |
| 689 | return false; |
| 690 | |
| 691 | subflow_generate_hmac(msk->remote_key, msk->local_key, |
| 692 | subflow_req->remote_nonce, |
| 693 | subflow_req->local_nonce, hmac); |
| 694 | |
| 695 | return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN); |
| 696 | } |
| 697 | |
| 698 | static void subflow_ulp_fallback(struct sock *sk, |
| 699 | struct mptcp_subflow_context *old_ctx) |
| 700 | { |
| 701 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 702 | |
| 703 | mptcp_subflow_tcp_fallback(sk, old_ctx); |
| 704 | icsk->icsk_ulp_ops = NULL; |
| 705 | rcu_assign_pointer(icsk->icsk_ulp_data, NULL); |
| 706 | tcp_sk(sk)->is_mptcp = 0; |
| 707 | |
| 708 | mptcp_subflow_ops_undo_override(sk); |
| 709 | } |
| 710 | |
| 711 | void mptcp_subflow_drop_ctx(struct sock *ssk) |
| 712 | { |
| 713 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); |
| 714 | |
| 715 | if (!ctx) |
| 716 | return; |
| 717 | |
| 718 | list_del(&mptcp_subflow_ctx(ssk)->node); |
| 719 | if (inet_csk(ssk)->icsk_ulp_ops) { |
| 720 | subflow_ulp_fallback(ssk, ctx); |
| 721 | if (ctx->conn) |
| 722 | sock_put(ctx->conn); |
| 723 | } |
| 724 | |
| 725 | kfree_rcu(ctx, rcu); |
| 726 | } |
| 727 | |
| 728 | void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow, |
| 729 | const struct mptcp_options_received *mp_opt) |
| 730 | { |
| 731 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| 732 | |
| 733 | subflow_set_remote_key(msk, subflow, mp_opt); |
| 734 | subflow->fully_established = 1; |
| 735 | WRITE_ONCE(msk->fully_established, true); |
| 736 | |
| 737 | if (subflow->is_mptfo) |
| 738 | mptcp_fastopen_gen_msk_ackseq(msk, subflow, mp_opt); |
| 739 | } |
| 740 | |
| 741 | static struct sock *subflow_syn_recv_sock(const struct sock *sk, |
| 742 | struct sk_buff *skb, |
| 743 | struct request_sock *req, |
| 744 | struct dst_entry *dst, |
| 745 | struct request_sock *req_unhash, |
| 746 | bool *own_req) |
| 747 | { |
| 748 | struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk); |
| 749 | struct mptcp_subflow_request_sock *subflow_req; |
| 750 | struct mptcp_options_received mp_opt; |
| 751 | bool fallback, fallback_is_fatal; |
| 752 | struct mptcp_sock *owner; |
| 753 | struct sock *child; |
| 754 | |
| 755 | pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn); |
| 756 | |
| 757 | /* After child creation we must look for MPC even when options |
| 758 | * are not parsed |
| 759 | */ |
| 760 | mp_opt.suboptions = 0; |
| 761 | |
| 762 | /* hopefully temporary handling for MP_JOIN+syncookie */ |
| 763 | subflow_req = mptcp_subflow_rsk(req); |
| 764 | fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join; |
| 765 | fallback = !tcp_rsk(req)->is_mptcp; |
| 766 | if (fallback) |
| 767 | goto create_child; |
| 768 | |
| 769 | /* if the sk is MP_CAPABLE, we try to fetch the client key */ |
| 770 | if (subflow_req->mp_capable) { |
| 771 | /* we can receive and accept an in-window, out-of-order pkt, |
| 772 | * which may not carry the MP_CAPABLE opt even on mptcp enabled |
| 773 | * paths: always try to extract the peer key, and fallback |
| 774 | * for packets missing it. |
| 775 | * Even OoO DSS packets coming legitly after dropped or |
| 776 | * reordered MPC will cause fallback, but we don't have other |
| 777 | * options. |
| 778 | */ |
| 779 | mptcp_get_options(skb, &mp_opt); |
| 780 | if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) |
| 781 | fallback = true; |
| 782 | |
| 783 | } else if (subflow_req->mp_join) { |
| 784 | mptcp_get_options(skb, &mp_opt); |
| 785 | if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) || |
| 786 | !subflow_hmac_valid(req, &mp_opt) || |
| 787 | !mptcp_can_accept_new_subflow(subflow_req->msk)) { |
| 788 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); |
| 789 | fallback = true; |
| 790 | } |
| 791 | } |
| 792 | |
| 793 | create_child: |
| 794 | child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst, |
| 795 | req_unhash, own_req); |
| 796 | |
| 797 | if (child && *own_req) { |
| 798 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child); |
| 799 | |
| 800 | tcp_rsk(req)->drop_req = false; |
| 801 | |
| 802 | /* we need to fallback on ctx allocation failure and on pre-reqs |
| 803 | * checking above. In the latter scenario we additionally need |
| 804 | * to reset the context to non MPTCP status. |
| 805 | */ |
| 806 | if (!ctx || fallback) { |
| 807 | if (fallback_is_fatal) { |
| 808 | subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP); |
| 809 | goto dispose_child; |
| 810 | } |
| 811 | goto fallback; |
| 812 | } |
| 813 | |
| 814 | /* ssk inherits options of listener sk */ |
| 815 | ctx->setsockopt_seq = listener->setsockopt_seq; |
| 816 | |
| 817 | if (ctx->mp_capable) { |
| 818 | ctx->conn = mptcp_sk_clone_init(listener->conn, &mp_opt, child, req); |
| 819 | if (!ctx->conn) |
| 820 | goto fallback; |
| 821 | |
| 822 | ctx->subflow_id = 1; |
| 823 | owner = mptcp_sk(ctx->conn); |
| 824 | mptcp_pm_new_connection(owner, child, 1); |
| 825 | |
| 826 | /* with OoO packets we can reach here without ingress |
| 827 | * mpc option |
| 828 | */ |
| 829 | if (mp_opt.suboptions & OPTION_MPTCP_MPC_ACK) { |
| 830 | mptcp_subflow_fully_established(ctx, &mp_opt); |
| 831 | mptcp_pm_fully_established(owner, child); |
| 832 | ctx->pm_notified = 1; |
| 833 | } |
| 834 | } else if (ctx->mp_join) { |
| 835 | owner = subflow_req->msk; |
| 836 | if (!owner) { |
| 837 | subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT); |
| 838 | goto dispose_child; |
| 839 | } |
| 840 | |
| 841 | /* move the msk reference ownership to the subflow */ |
| 842 | subflow_req->msk = NULL; |
| 843 | ctx->conn = (struct sock *)owner; |
| 844 | |
| 845 | if (subflow_use_different_sport(owner, sk)) { |
| 846 | pr_debug("ack inet_sport=%d %d", |
| 847 | ntohs(inet_sk(sk)->inet_sport), |
| 848 | ntohs(inet_sk((struct sock *)owner)->inet_sport)); |
| 849 | if (!mptcp_pm_sport_in_anno_list(owner, sk)) { |
| 850 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX); |
| 851 | goto dispose_child; |
| 852 | } |
| 853 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX); |
| 854 | } |
| 855 | |
| 856 | if (!mptcp_finish_join(child)) |
| 857 | goto dispose_child; |
| 858 | |
| 859 | SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX); |
| 860 | tcp_rsk(req)->drop_req = true; |
| 861 | } |
| 862 | } |
| 863 | |
| 864 | /* check for expected invariant - should never trigger, just help |
| 865 | * catching eariler subtle bugs |
| 866 | */ |
| 867 | WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp && |
| 868 | (!mptcp_subflow_ctx(child) || |
| 869 | !mptcp_subflow_ctx(child)->conn)); |
| 870 | return child; |
| 871 | |
| 872 | dispose_child: |
| 873 | mptcp_subflow_drop_ctx(child); |
| 874 | tcp_rsk(req)->drop_req = true; |
| 875 | inet_csk_prepare_for_destroy_sock(child); |
| 876 | tcp_done(child); |
| 877 | req->rsk_ops->send_reset(sk, skb); |
| 878 | |
| 879 | /* The last child reference will be released by the caller */ |
| 880 | return child; |
| 881 | |
| 882 | fallback: |
| 883 | mptcp_subflow_drop_ctx(child); |
| 884 | return child; |
| 885 | } |
| 886 | |
| 887 | static struct inet_connection_sock_af_ops subflow_specific __ro_after_init; |
| 888 | static struct proto tcp_prot_override __ro_after_init; |
| 889 | |
| 890 | enum mapping_status { |
| 891 | MAPPING_OK, |
| 892 | MAPPING_INVALID, |
| 893 | MAPPING_EMPTY, |
| 894 | MAPPING_DATA_FIN, |
| 895 | MAPPING_DUMMY, |
| 896 | MAPPING_BAD_CSUM |
| 897 | }; |
| 898 | |
| 899 | static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn) |
| 900 | { |
| 901 | pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d", |
| 902 | ssn, subflow->map_subflow_seq, subflow->map_data_len); |
| 903 | } |
| 904 | |
| 905 | static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb) |
| 906 | { |
| 907 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 908 | unsigned int skb_consumed; |
| 909 | |
| 910 | skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq; |
| 911 | if (WARN_ON_ONCE(skb_consumed >= skb->len)) |
| 912 | return true; |
| 913 | |
| 914 | return skb->len - skb_consumed <= subflow->map_data_len - |
| 915 | mptcp_subflow_get_map_offset(subflow); |
| 916 | } |
| 917 | |
| 918 | static bool validate_mapping(struct sock *ssk, struct sk_buff *skb) |
| 919 | { |
| 920 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 921 | u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; |
| 922 | |
| 923 | if (unlikely(before(ssn, subflow->map_subflow_seq))) { |
| 924 | /* Mapping covers data later in the subflow stream, |
| 925 | * currently unsupported. |
| 926 | */ |
| 927 | dbg_bad_map(subflow, ssn); |
| 928 | return false; |
| 929 | } |
| 930 | if (unlikely(!before(ssn, subflow->map_subflow_seq + |
| 931 | subflow->map_data_len))) { |
| 932 | /* Mapping does covers past subflow data, invalid */ |
| 933 | dbg_bad_map(subflow, ssn); |
| 934 | return false; |
| 935 | } |
| 936 | return true; |
| 937 | } |
| 938 | |
| 939 | static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *skb, |
| 940 | bool csum_reqd) |
| 941 | { |
| 942 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 943 | u32 offset, seq, delta; |
| 944 | __sum16 csum; |
| 945 | int len; |
| 946 | |
| 947 | if (!csum_reqd) |
| 948 | return MAPPING_OK; |
| 949 | |
| 950 | /* mapping already validated on previous traversal */ |
| 951 | if (subflow->map_csum_len == subflow->map_data_len) |
| 952 | return MAPPING_OK; |
| 953 | |
| 954 | /* traverse the receive queue, ensuring it contains a full |
| 955 | * DSS mapping and accumulating the related csum. |
| 956 | * Preserve the accoumlate csum across multiple calls, to compute |
| 957 | * the csum only once |
| 958 | */ |
| 959 | delta = subflow->map_data_len - subflow->map_csum_len; |
| 960 | for (;;) { |
| 961 | seq = tcp_sk(ssk)->copied_seq + subflow->map_csum_len; |
| 962 | offset = seq - TCP_SKB_CB(skb)->seq; |
| 963 | |
| 964 | /* if the current skb has not been accounted yet, csum its contents |
| 965 | * up to the amount covered by the current DSS |
| 966 | */ |
| 967 | if (offset < skb->len) { |
| 968 | __wsum csum; |
| 969 | |
| 970 | len = min(skb->len - offset, delta); |
| 971 | csum = skb_checksum(skb, offset, len, 0); |
| 972 | subflow->map_data_csum = csum_block_add(subflow->map_data_csum, csum, |
| 973 | subflow->map_csum_len); |
| 974 | |
| 975 | delta -= len; |
| 976 | subflow->map_csum_len += len; |
| 977 | } |
| 978 | if (delta == 0) |
| 979 | break; |
| 980 | |
| 981 | if (skb_queue_is_last(&ssk->sk_receive_queue, skb)) { |
| 982 | /* if this subflow is closed, the partial mapping |
| 983 | * will be never completed; flush the pending skbs, so |
| 984 | * that subflow_sched_work_if_closed() can kick in |
| 985 | */ |
| 986 | if (unlikely(ssk->sk_state == TCP_CLOSE)) |
| 987 | while ((skb = skb_peek(&ssk->sk_receive_queue))) |
| 988 | sk_eat_skb(ssk, skb); |
| 989 | |
| 990 | /* not enough data to validate the csum */ |
| 991 | return MAPPING_EMPTY; |
| 992 | } |
| 993 | |
| 994 | /* the DSS mapping for next skbs will be validated later, |
| 995 | * when a get_mapping_status call will process such skb |
| 996 | */ |
| 997 | skb = skb->next; |
| 998 | } |
| 999 | |
| 1000 | /* note that 'map_data_len' accounts only for the carried data, does |
| 1001 | * not include the eventual seq increment due to the data fin, |
| 1002 | * while the pseudo header requires the original DSS data len, |
| 1003 | * including that |
| 1004 | */ |
| 1005 | csum = __mptcp_make_csum(subflow->map_seq, |
| 1006 | subflow->map_subflow_seq, |
| 1007 | subflow->map_data_len + subflow->map_data_fin, |
| 1008 | subflow->map_data_csum); |
| 1009 | if (unlikely(csum)) { |
| 1010 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR); |
| 1011 | return MAPPING_BAD_CSUM; |
| 1012 | } |
| 1013 | |
| 1014 | subflow->valid_csum_seen = 1; |
| 1015 | return MAPPING_OK; |
| 1016 | } |
| 1017 | |
| 1018 | static enum mapping_status get_mapping_status(struct sock *ssk, |
| 1019 | struct mptcp_sock *msk) |
| 1020 | { |
| 1021 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1022 | bool csum_reqd = READ_ONCE(msk->csum_enabled); |
| 1023 | struct mptcp_ext *mpext; |
| 1024 | struct sk_buff *skb; |
| 1025 | u16 data_len; |
| 1026 | u64 map_seq; |
| 1027 | |
| 1028 | skb = skb_peek(&ssk->sk_receive_queue); |
| 1029 | if (!skb) |
| 1030 | return MAPPING_EMPTY; |
| 1031 | |
| 1032 | if (mptcp_check_fallback(ssk)) |
| 1033 | return MAPPING_DUMMY; |
| 1034 | |
| 1035 | mpext = mptcp_get_ext(skb); |
| 1036 | if (!mpext || !mpext->use_map) { |
| 1037 | if (!subflow->map_valid && !skb->len) { |
| 1038 | /* the TCP stack deliver 0 len FIN pkt to the receive |
| 1039 | * queue, that is the only 0len pkts ever expected here, |
| 1040 | * and we can admit no mapping only for 0 len pkts |
| 1041 | */ |
| 1042 | if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)) |
| 1043 | WARN_ONCE(1, "0len seq %d:%d flags %x", |
| 1044 | TCP_SKB_CB(skb)->seq, |
| 1045 | TCP_SKB_CB(skb)->end_seq, |
| 1046 | TCP_SKB_CB(skb)->tcp_flags); |
| 1047 | sk_eat_skb(ssk, skb); |
| 1048 | return MAPPING_EMPTY; |
| 1049 | } |
| 1050 | |
| 1051 | if (!subflow->map_valid) |
| 1052 | return MAPPING_INVALID; |
| 1053 | |
| 1054 | goto validate_seq; |
| 1055 | } |
| 1056 | |
| 1057 | trace_get_mapping_status(mpext); |
| 1058 | |
| 1059 | data_len = mpext->data_len; |
| 1060 | if (data_len == 0) { |
| 1061 | pr_debug("infinite mapping received"); |
| 1062 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX); |
| 1063 | subflow->map_data_len = 0; |
| 1064 | return MAPPING_INVALID; |
| 1065 | } |
| 1066 | |
| 1067 | if (mpext->data_fin == 1) { |
| 1068 | if (data_len == 1) { |
| 1069 | bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq, |
| 1070 | mpext->dsn64); |
| 1071 | pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq); |
| 1072 | if (subflow->map_valid) { |
| 1073 | /* A DATA_FIN might arrive in a DSS |
| 1074 | * option before the previous mapping |
| 1075 | * has been fully consumed. Continue |
| 1076 | * handling the existing mapping. |
| 1077 | */ |
| 1078 | skb_ext_del(skb, SKB_EXT_MPTCP); |
| 1079 | return MAPPING_OK; |
| 1080 | } else { |
| 1081 | if (updated) |
| 1082 | mptcp_schedule_work((struct sock *)msk); |
| 1083 | |
| 1084 | return MAPPING_DATA_FIN; |
| 1085 | } |
| 1086 | } else { |
| 1087 | u64 data_fin_seq = mpext->data_seq + data_len - 1; |
| 1088 | |
| 1089 | /* If mpext->data_seq is a 32-bit value, data_fin_seq |
| 1090 | * must also be limited to 32 bits. |
| 1091 | */ |
| 1092 | if (!mpext->dsn64) |
| 1093 | data_fin_seq &= GENMASK_ULL(31, 0); |
| 1094 | |
| 1095 | mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64); |
| 1096 | pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d", |
| 1097 | data_fin_seq, mpext->dsn64); |
| 1098 | } |
| 1099 | |
| 1100 | /* Adjust for DATA_FIN using 1 byte of sequence space */ |
| 1101 | data_len--; |
| 1102 | } |
| 1103 | |
| 1104 | map_seq = mptcp_expand_seq(READ_ONCE(msk->ack_seq), mpext->data_seq, mpext->dsn64); |
| 1105 | WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64); |
| 1106 | |
| 1107 | if (subflow->map_valid) { |
| 1108 | /* Allow replacing only with an identical map */ |
| 1109 | if (subflow->map_seq == map_seq && |
| 1110 | subflow->map_subflow_seq == mpext->subflow_seq && |
| 1111 | subflow->map_data_len == data_len && |
| 1112 | subflow->map_csum_reqd == mpext->csum_reqd) { |
| 1113 | skb_ext_del(skb, SKB_EXT_MPTCP); |
| 1114 | goto validate_csum; |
| 1115 | } |
| 1116 | |
| 1117 | /* If this skb data are fully covered by the current mapping, |
| 1118 | * the new map would need caching, which is not supported |
| 1119 | */ |
| 1120 | if (skb_is_fully_mapped(ssk, skb)) { |
| 1121 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH); |
| 1122 | return MAPPING_INVALID; |
| 1123 | } |
| 1124 | |
| 1125 | /* will validate the next map after consuming the current one */ |
| 1126 | goto validate_csum; |
| 1127 | } |
| 1128 | |
| 1129 | subflow->map_seq = map_seq; |
| 1130 | subflow->map_subflow_seq = mpext->subflow_seq; |
| 1131 | subflow->map_data_len = data_len; |
| 1132 | subflow->map_valid = 1; |
| 1133 | subflow->map_data_fin = mpext->data_fin; |
| 1134 | subflow->mpc_map = mpext->mpc_map; |
| 1135 | subflow->map_csum_reqd = mpext->csum_reqd; |
| 1136 | subflow->map_csum_len = 0; |
| 1137 | subflow->map_data_csum = csum_unfold(mpext->csum); |
| 1138 | |
| 1139 | /* Cfr RFC 8684 Section 3.3.0 */ |
| 1140 | if (unlikely(subflow->map_csum_reqd != csum_reqd)) |
| 1141 | return MAPPING_INVALID; |
| 1142 | |
| 1143 | pr_debug("new map seq=%llu subflow_seq=%u data_len=%u csum=%d:%u", |
| 1144 | subflow->map_seq, subflow->map_subflow_seq, |
| 1145 | subflow->map_data_len, subflow->map_csum_reqd, |
| 1146 | subflow->map_data_csum); |
| 1147 | |
| 1148 | validate_seq: |
| 1149 | /* we revalidate valid mapping on new skb, because we must ensure |
| 1150 | * the current skb is completely covered by the available mapping |
| 1151 | */ |
| 1152 | if (!validate_mapping(ssk, skb)) { |
| 1153 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSTCPMISMATCH); |
| 1154 | return MAPPING_INVALID; |
| 1155 | } |
| 1156 | |
| 1157 | skb_ext_del(skb, SKB_EXT_MPTCP); |
| 1158 | |
| 1159 | validate_csum: |
| 1160 | return validate_data_csum(ssk, skb, csum_reqd); |
| 1161 | } |
| 1162 | |
| 1163 | static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb, |
| 1164 | u64 limit) |
| 1165 | { |
| 1166 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1167 | bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; |
| 1168 | u32 incr; |
| 1169 | |
| 1170 | incr = limit >= skb->len ? skb->len + fin : limit; |
| 1171 | |
| 1172 | pr_debug("discarding=%d len=%d seq=%d", incr, skb->len, |
| 1173 | subflow->map_subflow_seq); |
| 1174 | MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA); |
| 1175 | tcp_sk(ssk)->copied_seq += incr; |
| 1176 | if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq)) |
| 1177 | sk_eat_skb(ssk, skb); |
| 1178 | if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) |
| 1179 | subflow->map_valid = 0; |
| 1180 | } |
| 1181 | |
| 1182 | /* sched mptcp worker to remove the subflow if no more data is pending */ |
| 1183 | static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk) |
| 1184 | { |
| 1185 | if (likely(ssk->sk_state != TCP_CLOSE)) |
| 1186 | return; |
| 1187 | |
| 1188 | if (skb_queue_empty(&ssk->sk_receive_queue) && |
| 1189 | !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) |
| 1190 | mptcp_schedule_work((struct sock *)msk); |
| 1191 | } |
| 1192 | |
| 1193 | static bool subflow_can_fallback(struct mptcp_subflow_context *subflow) |
| 1194 | { |
| 1195 | struct mptcp_sock *msk = mptcp_sk(subflow->conn); |
| 1196 | |
| 1197 | if (subflow->mp_join) |
| 1198 | return false; |
| 1199 | else if (READ_ONCE(msk->csum_enabled)) |
| 1200 | return !subflow->valid_csum_seen; |
| 1201 | else |
| 1202 | return !subflow->fully_established; |
| 1203 | } |
| 1204 | |
| 1205 | static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk) |
| 1206 | { |
| 1207 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1208 | unsigned long fail_tout; |
| 1209 | |
| 1210 | /* greceful failure can happen only on the MPC subflow */ |
| 1211 | if (WARN_ON_ONCE(ssk != READ_ONCE(msk->first))) |
| 1212 | return; |
| 1213 | |
| 1214 | /* since the close timeout take precedence on the fail one, |
| 1215 | * no need to start the latter when the first is already set |
| 1216 | */ |
| 1217 | if (sock_flag((struct sock *)msk, SOCK_DEAD)) |
| 1218 | return; |
| 1219 | |
| 1220 | /* we don't need extreme accuracy here, use a zero fail_tout as special |
| 1221 | * value meaning no fail timeout at all; |
| 1222 | */ |
| 1223 | fail_tout = jiffies + TCP_RTO_MAX; |
| 1224 | if (!fail_tout) |
| 1225 | fail_tout = 1; |
| 1226 | WRITE_ONCE(subflow->fail_tout, fail_tout); |
| 1227 | tcp_send_ack(ssk); |
| 1228 | |
| 1229 | mptcp_reset_tout_timer(msk, subflow->fail_tout); |
| 1230 | } |
| 1231 | |
| 1232 | static bool subflow_check_data_avail(struct sock *ssk) |
| 1233 | { |
| 1234 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1235 | enum mapping_status status; |
| 1236 | struct mptcp_sock *msk; |
| 1237 | struct sk_buff *skb; |
| 1238 | |
| 1239 | if (!skb_peek(&ssk->sk_receive_queue)) |
| 1240 | WRITE_ONCE(subflow->data_avail, false); |
| 1241 | if (subflow->data_avail) |
| 1242 | return true; |
| 1243 | |
| 1244 | msk = mptcp_sk(subflow->conn); |
| 1245 | for (;;) { |
| 1246 | u64 ack_seq; |
| 1247 | u64 old_ack; |
| 1248 | |
| 1249 | status = get_mapping_status(ssk, msk); |
| 1250 | trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue)); |
| 1251 | if (unlikely(status == MAPPING_INVALID || status == MAPPING_DUMMY || |
| 1252 | status == MAPPING_BAD_CSUM)) |
| 1253 | goto fallback; |
| 1254 | |
| 1255 | if (status != MAPPING_OK) |
| 1256 | goto no_data; |
| 1257 | |
| 1258 | skb = skb_peek(&ssk->sk_receive_queue); |
| 1259 | if (WARN_ON_ONCE(!skb)) |
| 1260 | goto no_data; |
| 1261 | |
| 1262 | if (unlikely(!READ_ONCE(msk->can_ack))) |
| 1263 | goto fallback; |
| 1264 | |
| 1265 | old_ack = READ_ONCE(msk->ack_seq); |
| 1266 | ack_seq = mptcp_subflow_get_mapped_dsn(subflow); |
| 1267 | pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack, |
| 1268 | ack_seq); |
| 1269 | if (unlikely(before64(ack_seq, old_ack))) { |
| 1270 | mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq); |
| 1271 | continue; |
| 1272 | } |
| 1273 | |
| 1274 | WRITE_ONCE(subflow->data_avail, true); |
| 1275 | break; |
| 1276 | } |
| 1277 | return true; |
| 1278 | |
| 1279 | no_data: |
| 1280 | subflow_sched_work_if_closed(msk, ssk); |
| 1281 | return false; |
| 1282 | |
| 1283 | fallback: |
| 1284 | if (!__mptcp_check_fallback(msk)) { |
| 1285 | /* RFC 8684 section 3.7. */ |
| 1286 | if (status == MAPPING_BAD_CSUM && |
| 1287 | (subflow->mp_join || subflow->valid_csum_seen)) { |
| 1288 | subflow->send_mp_fail = 1; |
| 1289 | |
| 1290 | if (!READ_ONCE(msk->allow_infinite_fallback)) { |
| 1291 | subflow->reset_transient = 0; |
| 1292 | subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; |
| 1293 | goto reset; |
| 1294 | } |
| 1295 | mptcp_subflow_fail(msk, ssk); |
| 1296 | WRITE_ONCE(subflow->data_avail, true); |
| 1297 | return true; |
| 1298 | } |
| 1299 | |
| 1300 | if (!subflow_can_fallback(subflow) && subflow->map_data_len) { |
| 1301 | /* fatal protocol error, close the socket. |
| 1302 | * subflow_error_report() will introduce the appropriate barriers |
| 1303 | */ |
| 1304 | subflow->reset_transient = 0; |
| 1305 | subflow->reset_reason = MPTCP_RST_EMPTCP; |
| 1306 | |
| 1307 | reset: |
| 1308 | WRITE_ONCE(ssk->sk_err, EBADMSG); |
| 1309 | tcp_set_state(ssk, TCP_CLOSE); |
| 1310 | while ((skb = skb_peek(&ssk->sk_receive_queue))) |
| 1311 | sk_eat_skb(ssk, skb); |
| 1312 | tcp_send_active_reset(ssk, GFP_ATOMIC); |
| 1313 | WRITE_ONCE(subflow->data_avail, false); |
| 1314 | return false; |
| 1315 | } |
| 1316 | |
| 1317 | mptcp_do_fallback(ssk); |
| 1318 | } |
| 1319 | |
| 1320 | skb = skb_peek(&ssk->sk_receive_queue); |
| 1321 | subflow->map_valid = 1; |
| 1322 | subflow->map_seq = READ_ONCE(msk->ack_seq); |
| 1323 | subflow->map_data_len = skb->len; |
| 1324 | subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset; |
| 1325 | WRITE_ONCE(subflow->data_avail, true); |
| 1326 | return true; |
| 1327 | } |
| 1328 | |
| 1329 | bool mptcp_subflow_data_available(struct sock *sk) |
| 1330 | { |
| 1331 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 1332 | |
| 1333 | /* check if current mapping is still valid */ |
| 1334 | if (subflow->map_valid && |
| 1335 | mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) { |
| 1336 | subflow->map_valid = 0; |
| 1337 | WRITE_ONCE(subflow->data_avail, false); |
| 1338 | |
| 1339 | pr_debug("Done with mapping: seq=%u data_len=%u", |
| 1340 | subflow->map_subflow_seq, |
| 1341 | subflow->map_data_len); |
| 1342 | } |
| 1343 | |
| 1344 | return subflow_check_data_avail(sk); |
| 1345 | } |
| 1346 | |
| 1347 | /* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy, |
| 1348 | * not the ssk one. |
| 1349 | * |
| 1350 | * In mptcp, rwin is about the mptcp-level connection data. |
| 1351 | * |
| 1352 | * Data that is still on the ssk rx queue can thus be ignored, |
| 1353 | * as far as mptcp peer is concerned that data is still inflight. |
| 1354 | * DSS ACK is updated when skb is moved to the mptcp rx queue. |
| 1355 | */ |
| 1356 | void mptcp_space(const struct sock *ssk, int *space, int *full_space) |
| 1357 | { |
| 1358 | const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1359 | const struct sock *sk = subflow->conn; |
| 1360 | |
| 1361 | *space = __mptcp_space(sk); |
| 1362 | *full_space = mptcp_win_from_space(sk, READ_ONCE(sk->sk_rcvbuf)); |
| 1363 | } |
| 1364 | |
| 1365 | static void subflow_error_report(struct sock *ssk) |
| 1366 | { |
| 1367 | struct sock *sk = mptcp_subflow_ctx(ssk)->conn; |
| 1368 | |
| 1369 | /* bail early if this is a no-op, so that we avoid introducing a |
| 1370 | * problematic lockdep dependency between TCP accept queue lock |
| 1371 | * and msk socket spinlock |
| 1372 | */ |
| 1373 | if (!sk->sk_socket) |
| 1374 | return; |
| 1375 | |
| 1376 | mptcp_data_lock(sk); |
| 1377 | if (!sock_owned_by_user(sk)) |
| 1378 | __mptcp_error_report(sk); |
| 1379 | else |
| 1380 | __set_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->cb_flags); |
| 1381 | mptcp_data_unlock(sk); |
| 1382 | } |
| 1383 | |
| 1384 | static void subflow_data_ready(struct sock *sk) |
| 1385 | { |
| 1386 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 1387 | u16 state = 1 << inet_sk_state_load(sk); |
| 1388 | struct sock *parent = subflow->conn; |
| 1389 | struct mptcp_sock *msk; |
| 1390 | |
| 1391 | trace_sk_data_ready(sk); |
| 1392 | |
| 1393 | msk = mptcp_sk(parent); |
| 1394 | if (state & TCPF_LISTEN) { |
| 1395 | /* MPJ subflow are removed from accept queue before reaching here, |
| 1396 | * avoid stray wakeups |
| 1397 | */ |
| 1398 | if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue)) |
| 1399 | return; |
| 1400 | |
| 1401 | parent->sk_data_ready(parent); |
| 1402 | return; |
| 1403 | } |
| 1404 | |
| 1405 | WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable && |
| 1406 | !subflow->mp_join && !(state & TCPF_CLOSE)); |
| 1407 | |
| 1408 | if (mptcp_subflow_data_available(sk)) { |
| 1409 | mptcp_data_ready(parent, sk); |
| 1410 | |
| 1411 | /* subflow-level lowat test are not relevant. |
| 1412 | * respect the msk-level threshold eventually mandating an immediate ack |
| 1413 | */ |
| 1414 | if (mptcp_data_avail(msk) < parent->sk_rcvlowat && |
| 1415 | (tcp_sk(sk)->rcv_nxt - tcp_sk(sk)->rcv_wup) > inet_csk(sk)->icsk_ack.rcv_mss) |
| 1416 | inet_csk(sk)->icsk_ack.pending |= ICSK_ACK_NOW; |
| 1417 | } else if (unlikely(sk->sk_err)) { |
| 1418 | subflow_error_report(sk); |
| 1419 | } |
| 1420 | } |
| 1421 | |
| 1422 | static void subflow_write_space(struct sock *ssk) |
| 1423 | { |
| 1424 | struct sock *sk = mptcp_subflow_ctx(ssk)->conn; |
| 1425 | |
| 1426 | mptcp_propagate_sndbuf(sk, ssk); |
| 1427 | mptcp_write_space(sk); |
| 1428 | } |
| 1429 | |
| 1430 | static const struct inet_connection_sock_af_ops * |
| 1431 | subflow_default_af_ops(struct sock *sk) |
| 1432 | { |
| 1433 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1434 | if (sk->sk_family == AF_INET6) |
| 1435 | return &subflow_v6_specific; |
| 1436 | #endif |
| 1437 | return &subflow_specific; |
| 1438 | } |
| 1439 | |
| 1440 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1441 | void mptcpv6_handle_mapped(struct sock *sk, bool mapped) |
| 1442 | { |
| 1443 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 1444 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 1445 | const struct inet_connection_sock_af_ops *target; |
| 1446 | |
| 1447 | target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk); |
| 1448 | |
| 1449 | pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d", |
| 1450 | subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped); |
| 1451 | |
| 1452 | if (likely(icsk->icsk_af_ops == target)) |
| 1453 | return; |
| 1454 | |
| 1455 | subflow->icsk_af_ops = icsk->icsk_af_ops; |
| 1456 | icsk->icsk_af_ops = target; |
| 1457 | } |
| 1458 | #endif |
| 1459 | |
| 1460 | void mptcp_info2sockaddr(const struct mptcp_addr_info *info, |
| 1461 | struct sockaddr_storage *addr, |
| 1462 | unsigned short family) |
| 1463 | { |
| 1464 | memset(addr, 0, sizeof(*addr)); |
| 1465 | addr->ss_family = family; |
| 1466 | if (addr->ss_family == AF_INET) { |
| 1467 | struct sockaddr_in *in_addr = (struct sockaddr_in *)addr; |
| 1468 | |
| 1469 | if (info->family == AF_INET) |
| 1470 | in_addr->sin_addr = info->addr; |
| 1471 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1472 | else if (ipv6_addr_v4mapped(&info->addr6)) |
| 1473 | in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3]; |
| 1474 | #endif |
| 1475 | in_addr->sin_port = info->port; |
| 1476 | } |
| 1477 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1478 | else if (addr->ss_family == AF_INET6) { |
| 1479 | struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr; |
| 1480 | |
| 1481 | if (info->family == AF_INET) |
| 1482 | ipv6_addr_set_v4mapped(info->addr.s_addr, |
| 1483 | &in6_addr->sin6_addr); |
| 1484 | else |
| 1485 | in6_addr->sin6_addr = info->addr6; |
| 1486 | in6_addr->sin6_port = info->port; |
| 1487 | } |
| 1488 | #endif |
| 1489 | } |
| 1490 | |
| 1491 | int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, |
| 1492 | const struct mptcp_addr_info *remote) |
| 1493 | { |
| 1494 | struct mptcp_sock *msk = mptcp_sk(sk); |
| 1495 | struct mptcp_subflow_context *subflow; |
| 1496 | struct sockaddr_storage addr; |
| 1497 | int remote_id = remote->id; |
| 1498 | int local_id = loc->id; |
| 1499 | int err = -ENOTCONN; |
| 1500 | struct socket *sf; |
| 1501 | struct sock *ssk; |
| 1502 | u32 remote_token; |
| 1503 | int addrlen; |
| 1504 | int ifindex; |
| 1505 | u8 flags; |
| 1506 | |
| 1507 | if (!mptcp_is_fully_established(sk)) |
| 1508 | goto err_out; |
| 1509 | |
| 1510 | err = mptcp_subflow_create_socket(sk, loc->family, &sf); |
| 1511 | if (err) |
| 1512 | goto err_out; |
| 1513 | |
| 1514 | ssk = sf->sk; |
| 1515 | subflow = mptcp_subflow_ctx(ssk); |
| 1516 | do { |
| 1517 | get_random_bytes(&subflow->local_nonce, sizeof(u32)); |
| 1518 | } while (!subflow->local_nonce); |
| 1519 | |
| 1520 | if (local_id) |
| 1521 | subflow_set_local_id(subflow, local_id); |
| 1522 | |
| 1523 | mptcp_pm_get_flags_and_ifindex_by_id(msk, local_id, |
| 1524 | &flags, &ifindex); |
| 1525 | subflow->remote_key_valid = 1; |
| 1526 | subflow->remote_key = msk->remote_key; |
| 1527 | subflow->local_key = msk->local_key; |
| 1528 | subflow->token = msk->token; |
| 1529 | mptcp_info2sockaddr(loc, &addr, ssk->sk_family); |
| 1530 | |
| 1531 | addrlen = sizeof(struct sockaddr_in); |
| 1532 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1533 | if (addr.ss_family == AF_INET6) |
| 1534 | addrlen = sizeof(struct sockaddr_in6); |
| 1535 | #endif |
| 1536 | mptcp_sockopt_sync(msk, ssk); |
| 1537 | |
| 1538 | ssk->sk_bound_dev_if = ifindex; |
| 1539 | err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen); |
| 1540 | if (err) |
| 1541 | goto failed; |
| 1542 | |
| 1543 | mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL); |
| 1544 | pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk, |
| 1545 | remote_token, local_id, remote_id); |
| 1546 | subflow->remote_token = remote_token; |
| 1547 | subflow->remote_id = remote_id; |
| 1548 | subflow->request_join = 1; |
| 1549 | subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP); |
| 1550 | subflow->subflow_id = msk->subflow_id++; |
| 1551 | mptcp_info2sockaddr(remote, &addr, ssk->sk_family); |
| 1552 | |
| 1553 | sock_hold(ssk); |
| 1554 | list_add_tail(&subflow->node, &msk->conn_list); |
| 1555 | err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK); |
| 1556 | if (err && err != -EINPROGRESS) |
| 1557 | goto failed_unlink; |
| 1558 | |
| 1559 | /* discard the subflow socket */ |
| 1560 | mptcp_sock_graft(ssk, sk->sk_socket); |
| 1561 | iput(SOCK_INODE(sf)); |
| 1562 | WRITE_ONCE(msk->allow_infinite_fallback, false); |
| 1563 | mptcp_stop_tout_timer(sk); |
| 1564 | return 0; |
| 1565 | |
| 1566 | failed_unlink: |
| 1567 | list_del(&subflow->node); |
| 1568 | sock_put(mptcp_subflow_tcp_sock(subflow)); |
| 1569 | |
| 1570 | failed: |
| 1571 | subflow->disposable = 1; |
| 1572 | sock_release(sf); |
| 1573 | |
| 1574 | err_out: |
| 1575 | /* we account subflows before the creation, and this failures will not |
| 1576 | * be caught by sk_state_change() |
| 1577 | */ |
| 1578 | mptcp_pm_close_subflow(msk); |
| 1579 | return err; |
| 1580 | } |
| 1581 | |
| 1582 | static void mptcp_attach_cgroup(struct sock *parent, struct sock *child) |
| 1583 | { |
| 1584 | #ifdef CONFIG_SOCK_CGROUP_DATA |
| 1585 | struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data, |
| 1586 | *child_skcd = &child->sk_cgrp_data; |
| 1587 | |
| 1588 | /* only the additional subflows created by kworkers have to be modified */ |
| 1589 | if (cgroup_id(sock_cgroup_ptr(parent_skcd)) != |
| 1590 | cgroup_id(sock_cgroup_ptr(child_skcd))) { |
| 1591 | #ifdef CONFIG_MEMCG |
| 1592 | struct mem_cgroup *memcg = parent->sk_memcg; |
| 1593 | |
| 1594 | mem_cgroup_sk_free(child); |
| 1595 | if (memcg && css_tryget(&memcg->css)) |
| 1596 | child->sk_memcg = memcg; |
| 1597 | #endif /* CONFIG_MEMCG */ |
| 1598 | |
| 1599 | cgroup_sk_free(child_skcd); |
| 1600 | *child_skcd = *parent_skcd; |
| 1601 | cgroup_sk_clone(child_skcd); |
| 1602 | } |
| 1603 | #endif /* CONFIG_SOCK_CGROUP_DATA */ |
| 1604 | } |
| 1605 | |
| 1606 | static void mptcp_subflow_ops_override(struct sock *ssk) |
| 1607 | { |
| 1608 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1609 | if (ssk->sk_prot == &tcpv6_prot) |
| 1610 | ssk->sk_prot = &tcpv6_prot_override; |
| 1611 | else |
| 1612 | #endif |
| 1613 | ssk->sk_prot = &tcp_prot_override; |
| 1614 | } |
| 1615 | |
| 1616 | static void mptcp_subflow_ops_undo_override(struct sock *ssk) |
| 1617 | { |
| 1618 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 1619 | if (ssk->sk_prot == &tcpv6_prot_override) |
| 1620 | ssk->sk_prot = &tcpv6_prot; |
| 1621 | else |
| 1622 | #endif |
| 1623 | ssk->sk_prot = &tcp_prot; |
| 1624 | } |
| 1625 | |
| 1626 | int mptcp_subflow_create_socket(struct sock *sk, unsigned short family, |
| 1627 | struct socket **new_sock) |
| 1628 | { |
| 1629 | struct mptcp_subflow_context *subflow; |
| 1630 | struct net *net = sock_net(sk); |
| 1631 | struct socket *sf; |
| 1632 | int err; |
| 1633 | |
| 1634 | /* un-accepted server sockets can reach here - on bad configuration |
| 1635 | * bail early to avoid greater trouble later |
| 1636 | */ |
| 1637 | if (unlikely(!sk->sk_socket)) |
| 1638 | return -EINVAL; |
| 1639 | |
| 1640 | err = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP, &sf); |
| 1641 | if (err) |
| 1642 | return err; |
| 1643 | |
| 1644 | lock_sock_nested(sf->sk, SINGLE_DEPTH_NESTING); |
| 1645 | |
| 1646 | err = security_mptcp_add_subflow(sk, sf->sk); |
| 1647 | if (err) |
| 1648 | goto release_ssk; |
| 1649 | |
| 1650 | /* the newly created socket has to be in the same cgroup as its parent */ |
| 1651 | mptcp_attach_cgroup(sk, sf->sk); |
| 1652 | |
| 1653 | /* kernel sockets do not by default acquire net ref, but TCP timer |
| 1654 | * needs it. |
| 1655 | * Update ns_tracker to current stack trace and refcounted tracker. |
| 1656 | */ |
| 1657 | __netns_tracker_free(net, &sf->sk->ns_tracker, false); |
| 1658 | sf->sk->sk_net_refcnt = 1; |
| 1659 | get_net_track(net, &sf->sk->ns_tracker, GFP_KERNEL); |
| 1660 | sock_inuse_add(net, 1); |
| 1661 | err = tcp_set_ulp(sf->sk, "mptcp"); |
| 1662 | |
| 1663 | release_ssk: |
| 1664 | release_sock(sf->sk); |
| 1665 | |
| 1666 | if (err) { |
| 1667 | sock_release(sf); |
| 1668 | return err; |
| 1669 | } |
| 1670 | |
| 1671 | /* the newly created socket really belongs to the owning MPTCP master |
| 1672 | * socket, even if for additional subflows the allocation is performed |
| 1673 | * by a kernel workqueue. Adjust inode references, so that the |
| 1674 | * procfs/diag interfaces really show this one belonging to the correct |
| 1675 | * user. |
| 1676 | */ |
| 1677 | SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino; |
| 1678 | SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid; |
| 1679 | SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid; |
| 1680 | |
| 1681 | subflow = mptcp_subflow_ctx(sf->sk); |
| 1682 | pr_debug("subflow=%p", subflow); |
| 1683 | |
| 1684 | *new_sock = sf; |
| 1685 | sock_hold(sk); |
| 1686 | subflow->conn = sk; |
| 1687 | mptcp_subflow_ops_override(sf->sk); |
| 1688 | |
| 1689 | return 0; |
| 1690 | } |
| 1691 | |
| 1692 | static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk, |
| 1693 | gfp_t priority) |
| 1694 | { |
| 1695 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 1696 | struct mptcp_subflow_context *ctx; |
| 1697 | |
| 1698 | ctx = kzalloc(sizeof(*ctx), priority); |
| 1699 | if (!ctx) |
| 1700 | return NULL; |
| 1701 | |
| 1702 | rcu_assign_pointer(icsk->icsk_ulp_data, ctx); |
| 1703 | INIT_LIST_HEAD(&ctx->node); |
| 1704 | INIT_LIST_HEAD(&ctx->delegated_node); |
| 1705 | |
| 1706 | pr_debug("subflow=%p", ctx); |
| 1707 | |
| 1708 | ctx->tcp_sock = sk; |
| 1709 | |
| 1710 | return ctx; |
| 1711 | } |
| 1712 | |
| 1713 | static void __subflow_state_change(struct sock *sk) |
| 1714 | { |
| 1715 | struct socket_wq *wq; |
| 1716 | |
| 1717 | rcu_read_lock(); |
| 1718 | wq = rcu_dereference(sk->sk_wq); |
| 1719 | if (skwq_has_sleeper(wq)) |
| 1720 | wake_up_interruptible_all(&wq->wait); |
| 1721 | rcu_read_unlock(); |
| 1722 | } |
| 1723 | |
| 1724 | static bool subflow_is_done(const struct sock *sk) |
| 1725 | { |
| 1726 | return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE; |
| 1727 | } |
| 1728 | |
| 1729 | static void subflow_state_change(struct sock *sk) |
| 1730 | { |
| 1731 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| 1732 | struct sock *parent = subflow->conn; |
| 1733 | struct mptcp_sock *msk; |
| 1734 | |
| 1735 | __subflow_state_change(sk); |
| 1736 | |
| 1737 | msk = mptcp_sk(parent); |
| 1738 | if (subflow_simultaneous_connect(sk)) { |
| 1739 | mptcp_propagate_sndbuf(parent, sk); |
| 1740 | mptcp_do_fallback(sk); |
| 1741 | mptcp_rcv_space_init(msk, sk); |
| 1742 | pr_fallback(msk); |
| 1743 | subflow->conn_finished = 1; |
| 1744 | mptcp_set_connected(parent); |
| 1745 | } |
| 1746 | |
| 1747 | /* as recvmsg() does not acquire the subflow socket for ssk selection |
| 1748 | * a fin packet carrying a DSS can be unnoticed if we don't trigger |
| 1749 | * the data available machinery here. |
| 1750 | */ |
| 1751 | if (mptcp_subflow_data_available(sk)) |
| 1752 | mptcp_data_ready(parent, sk); |
| 1753 | else if (unlikely(sk->sk_err)) |
| 1754 | subflow_error_report(sk); |
| 1755 | |
| 1756 | subflow_sched_work_if_closed(mptcp_sk(parent), sk); |
| 1757 | |
| 1758 | /* when the fallback subflow closes the rx side, trigger a 'dummy' |
| 1759 | * ingress data fin, so that the msk state will follow along |
| 1760 | */ |
| 1761 | if (__mptcp_check_fallback(msk) && subflow_is_done(sk) && msk->first == sk && |
| 1762 | mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true)) |
| 1763 | mptcp_schedule_work(parent); |
| 1764 | } |
| 1765 | |
| 1766 | void mptcp_subflow_queue_clean(struct sock *listener_sk, struct sock *listener_ssk) |
| 1767 | { |
| 1768 | struct request_sock_queue *queue = &inet_csk(listener_ssk)->icsk_accept_queue; |
| 1769 | struct request_sock *req, *head, *tail; |
| 1770 | struct mptcp_subflow_context *subflow; |
| 1771 | struct sock *sk, *ssk; |
| 1772 | |
| 1773 | /* Due to lock dependencies no relevant lock can be acquired under rskq_lock. |
| 1774 | * Splice the req list, so that accept() can not reach the pending ssk after |
| 1775 | * the listener socket is released below. |
| 1776 | */ |
| 1777 | spin_lock_bh(&queue->rskq_lock); |
| 1778 | head = queue->rskq_accept_head; |
| 1779 | tail = queue->rskq_accept_tail; |
| 1780 | queue->rskq_accept_head = NULL; |
| 1781 | queue->rskq_accept_tail = NULL; |
| 1782 | spin_unlock_bh(&queue->rskq_lock); |
| 1783 | |
| 1784 | if (!head) |
| 1785 | return; |
| 1786 | |
| 1787 | /* can't acquire the msk socket lock under the subflow one, |
| 1788 | * or will cause ABBA deadlock |
| 1789 | */ |
| 1790 | release_sock(listener_ssk); |
| 1791 | |
| 1792 | for (req = head; req; req = req->dl_next) { |
| 1793 | ssk = req->sk; |
| 1794 | if (!sk_is_mptcp(ssk)) |
| 1795 | continue; |
| 1796 | |
| 1797 | subflow = mptcp_subflow_ctx(ssk); |
| 1798 | if (!subflow || !subflow->conn) |
| 1799 | continue; |
| 1800 | |
| 1801 | sk = subflow->conn; |
| 1802 | sock_hold(sk); |
| 1803 | |
| 1804 | lock_sock_nested(sk, SINGLE_DEPTH_NESTING); |
| 1805 | __mptcp_unaccepted_force_close(sk); |
| 1806 | release_sock(sk); |
| 1807 | |
| 1808 | /* lockdep will report a false positive ABBA deadlock |
| 1809 | * between cancel_work_sync and the listener socket. |
| 1810 | * The involved locks belong to different sockets WRT |
| 1811 | * the existing AB chain. |
| 1812 | * Using a per socket key is problematic as key |
| 1813 | * deregistration requires process context and must be |
| 1814 | * performed at socket disposal time, in atomic |
| 1815 | * context. |
| 1816 | * Just tell lockdep to consider the listener socket |
| 1817 | * released here. |
| 1818 | */ |
| 1819 | mutex_release(&listener_sk->sk_lock.dep_map, _RET_IP_); |
| 1820 | mptcp_cancel_work(sk); |
| 1821 | mutex_acquire(&listener_sk->sk_lock.dep_map, 0, 0, _RET_IP_); |
| 1822 | |
| 1823 | sock_put(sk); |
| 1824 | } |
| 1825 | |
| 1826 | /* we are still under the listener msk socket lock */ |
| 1827 | lock_sock_nested(listener_ssk, SINGLE_DEPTH_NESTING); |
| 1828 | |
| 1829 | /* restore the listener queue, to let the TCP code clean it up */ |
| 1830 | spin_lock_bh(&queue->rskq_lock); |
| 1831 | WARN_ON_ONCE(queue->rskq_accept_head); |
| 1832 | queue->rskq_accept_head = head; |
| 1833 | queue->rskq_accept_tail = tail; |
| 1834 | spin_unlock_bh(&queue->rskq_lock); |
| 1835 | } |
| 1836 | |
| 1837 | static int subflow_ulp_init(struct sock *sk) |
| 1838 | { |
| 1839 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 1840 | struct mptcp_subflow_context *ctx; |
| 1841 | struct tcp_sock *tp = tcp_sk(sk); |
| 1842 | int err = 0; |
| 1843 | |
| 1844 | /* disallow attaching ULP to a socket unless it has been |
| 1845 | * created with sock_create_kern() |
| 1846 | */ |
| 1847 | if (!sk->sk_kern_sock) { |
| 1848 | err = -EOPNOTSUPP; |
| 1849 | goto out; |
| 1850 | } |
| 1851 | |
| 1852 | ctx = subflow_create_ctx(sk, GFP_KERNEL); |
| 1853 | if (!ctx) { |
| 1854 | err = -ENOMEM; |
| 1855 | goto out; |
| 1856 | } |
| 1857 | |
| 1858 | pr_debug("subflow=%p, family=%d", ctx, sk->sk_family); |
| 1859 | |
| 1860 | tp->is_mptcp = 1; |
| 1861 | ctx->icsk_af_ops = icsk->icsk_af_ops; |
| 1862 | icsk->icsk_af_ops = subflow_default_af_ops(sk); |
| 1863 | ctx->tcp_state_change = sk->sk_state_change; |
| 1864 | ctx->tcp_error_report = sk->sk_error_report; |
| 1865 | |
| 1866 | WARN_ON_ONCE(sk->sk_data_ready != sock_def_readable); |
| 1867 | WARN_ON_ONCE(sk->sk_write_space != sk_stream_write_space); |
| 1868 | |
| 1869 | sk->sk_data_ready = subflow_data_ready; |
| 1870 | sk->sk_write_space = subflow_write_space; |
| 1871 | sk->sk_state_change = subflow_state_change; |
| 1872 | sk->sk_error_report = subflow_error_report; |
| 1873 | out: |
| 1874 | return err; |
| 1875 | } |
| 1876 | |
| 1877 | static void subflow_ulp_release(struct sock *ssk) |
| 1878 | { |
| 1879 | struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk); |
| 1880 | bool release = true; |
| 1881 | struct sock *sk; |
| 1882 | |
| 1883 | if (!ctx) |
| 1884 | return; |
| 1885 | |
| 1886 | sk = ctx->conn; |
| 1887 | if (sk) { |
| 1888 | /* if the msk has been orphaned, keep the ctx |
| 1889 | * alive, will be freed by __mptcp_close_ssk(), |
| 1890 | * when the subflow is still unaccepted |
| 1891 | */ |
| 1892 | release = ctx->disposable || list_empty(&ctx->node); |
| 1893 | |
| 1894 | /* inet_child_forget() does not call sk_state_change(), |
| 1895 | * explicitly trigger the socket close machinery |
| 1896 | */ |
| 1897 | if (!release && !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, |
| 1898 | &mptcp_sk(sk)->flags)) |
| 1899 | mptcp_schedule_work(sk); |
| 1900 | sock_put(sk); |
| 1901 | } |
| 1902 | |
| 1903 | mptcp_subflow_ops_undo_override(ssk); |
| 1904 | if (release) |
| 1905 | kfree_rcu(ctx, rcu); |
| 1906 | } |
| 1907 | |
| 1908 | static void subflow_ulp_clone(const struct request_sock *req, |
| 1909 | struct sock *newsk, |
| 1910 | const gfp_t priority) |
| 1911 | { |
| 1912 | struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req); |
| 1913 | struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk); |
| 1914 | struct mptcp_subflow_context *new_ctx; |
| 1915 | |
| 1916 | if (!tcp_rsk(req)->is_mptcp || |
| 1917 | (!subflow_req->mp_capable && !subflow_req->mp_join)) { |
| 1918 | subflow_ulp_fallback(newsk, old_ctx); |
| 1919 | return; |
| 1920 | } |
| 1921 | |
| 1922 | new_ctx = subflow_create_ctx(newsk, priority); |
| 1923 | if (!new_ctx) { |
| 1924 | subflow_ulp_fallback(newsk, old_ctx); |
| 1925 | return; |
| 1926 | } |
| 1927 | |
| 1928 | new_ctx->conn_finished = 1; |
| 1929 | new_ctx->icsk_af_ops = old_ctx->icsk_af_ops; |
| 1930 | new_ctx->tcp_state_change = old_ctx->tcp_state_change; |
| 1931 | new_ctx->tcp_error_report = old_ctx->tcp_error_report; |
| 1932 | new_ctx->rel_write_seq = 1; |
| 1933 | new_ctx->tcp_sock = newsk; |
| 1934 | |
| 1935 | if (subflow_req->mp_capable) { |
| 1936 | /* see comments in subflow_syn_recv_sock(), MPTCP connection |
| 1937 | * is fully established only after we receive the remote key |
| 1938 | */ |
| 1939 | new_ctx->mp_capable = 1; |
| 1940 | new_ctx->local_key = subflow_req->local_key; |
| 1941 | new_ctx->token = subflow_req->token; |
| 1942 | new_ctx->ssn_offset = subflow_req->ssn_offset; |
| 1943 | new_ctx->idsn = subflow_req->idsn; |
| 1944 | |
| 1945 | /* this is the first subflow, id is always 0 */ |
| 1946 | new_ctx->local_id_valid = 1; |
| 1947 | } else if (subflow_req->mp_join) { |
| 1948 | new_ctx->ssn_offset = subflow_req->ssn_offset; |
| 1949 | new_ctx->mp_join = 1; |
| 1950 | new_ctx->fully_established = 1; |
| 1951 | new_ctx->remote_key_valid = 1; |
| 1952 | new_ctx->backup = subflow_req->backup; |
| 1953 | new_ctx->remote_id = subflow_req->remote_id; |
| 1954 | new_ctx->token = subflow_req->token; |
| 1955 | new_ctx->thmac = subflow_req->thmac; |
| 1956 | |
| 1957 | /* the subflow req id is valid, fetched via subflow_check_req() |
| 1958 | * and subflow_token_join_request() |
| 1959 | */ |
| 1960 | subflow_set_local_id(new_ctx, subflow_req->local_id); |
| 1961 | } |
| 1962 | } |
| 1963 | |
| 1964 | static void tcp_release_cb_override(struct sock *ssk) |
| 1965 | { |
| 1966 | struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); |
| 1967 | long status; |
| 1968 | |
| 1969 | /* process and clear all the pending actions, but leave the subflow into |
| 1970 | * the napi queue. To respect locking, only the same CPU that originated |
| 1971 | * the action can touch the list. mptcp_napi_poll will take care of it. |
| 1972 | */ |
| 1973 | status = set_mask_bits(&subflow->delegated_status, MPTCP_DELEGATE_ACTIONS_MASK, 0); |
| 1974 | if (status) |
| 1975 | mptcp_subflow_process_delegated(ssk, status); |
| 1976 | |
| 1977 | tcp_release_cb(ssk); |
| 1978 | } |
| 1979 | |
| 1980 | static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = { |
| 1981 | .name = "mptcp", |
| 1982 | .owner = THIS_MODULE, |
| 1983 | .init = subflow_ulp_init, |
| 1984 | .release = subflow_ulp_release, |
| 1985 | .clone = subflow_ulp_clone, |
| 1986 | }; |
| 1987 | |
| 1988 | static int subflow_ops_init(struct request_sock_ops *subflow_ops) |
| 1989 | { |
| 1990 | subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock); |
| 1991 | |
| 1992 | subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name, |
| 1993 | subflow_ops->obj_size, 0, |
| 1994 | SLAB_ACCOUNT | |
| 1995 | SLAB_TYPESAFE_BY_RCU, |
| 1996 | NULL); |
| 1997 | if (!subflow_ops->slab) |
| 1998 | return -ENOMEM; |
| 1999 | |
| 2000 | return 0; |
| 2001 | } |
| 2002 | |
| 2003 | void __init mptcp_subflow_init(void) |
| 2004 | { |
| 2005 | mptcp_subflow_v4_request_sock_ops = tcp_request_sock_ops; |
| 2006 | mptcp_subflow_v4_request_sock_ops.slab_name = "request_sock_subflow_v4"; |
| 2007 | mptcp_subflow_v4_request_sock_ops.destructor = subflow_v4_req_destructor; |
| 2008 | |
| 2009 | if (subflow_ops_init(&mptcp_subflow_v4_request_sock_ops) != 0) |
| 2010 | panic("MPTCP: failed to init subflow v4 request sock ops\n"); |
| 2011 | |
| 2012 | subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops; |
| 2013 | subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req; |
| 2014 | subflow_request_sock_ipv4_ops.send_synack = subflow_v4_send_synack; |
| 2015 | |
| 2016 | subflow_specific = ipv4_specific; |
| 2017 | subflow_specific.conn_request = subflow_v4_conn_request; |
| 2018 | subflow_specific.syn_recv_sock = subflow_syn_recv_sock; |
| 2019 | subflow_specific.sk_rx_dst_set = subflow_finish_connect; |
| 2020 | subflow_specific.rebuild_header = subflow_rebuild_header; |
| 2021 | |
| 2022 | tcp_prot_override = tcp_prot; |
| 2023 | tcp_prot_override.release_cb = tcp_release_cb_override; |
| 2024 | |
| 2025 | #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| 2026 | /* In struct mptcp_subflow_request_sock, we assume the TCP request sock |
| 2027 | * structures for v4 and v6 have the same size. It should not changed in |
| 2028 | * the future but better to make sure to be warned if it is no longer |
| 2029 | * the case. |
| 2030 | */ |
| 2031 | BUILD_BUG_ON(sizeof(struct tcp_request_sock) != sizeof(struct tcp6_request_sock)); |
| 2032 | |
| 2033 | mptcp_subflow_v6_request_sock_ops = tcp6_request_sock_ops; |
| 2034 | mptcp_subflow_v6_request_sock_ops.slab_name = "request_sock_subflow_v6"; |
| 2035 | mptcp_subflow_v6_request_sock_ops.destructor = subflow_v6_req_destructor; |
| 2036 | |
| 2037 | if (subflow_ops_init(&mptcp_subflow_v6_request_sock_ops) != 0) |
| 2038 | panic("MPTCP: failed to init subflow v6 request sock ops\n"); |
| 2039 | |
| 2040 | subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops; |
| 2041 | subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req; |
| 2042 | subflow_request_sock_ipv6_ops.send_synack = subflow_v6_send_synack; |
| 2043 | |
| 2044 | subflow_v6_specific = ipv6_specific; |
| 2045 | subflow_v6_specific.conn_request = subflow_v6_conn_request; |
| 2046 | subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock; |
| 2047 | subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect; |
| 2048 | subflow_v6_specific.rebuild_header = subflow_v6_rebuild_header; |
| 2049 | |
| 2050 | subflow_v6m_specific = subflow_v6_specific; |
| 2051 | subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit; |
| 2052 | subflow_v6m_specific.send_check = ipv4_specific.send_check; |
| 2053 | subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len; |
| 2054 | subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced; |
| 2055 | subflow_v6m_specific.net_frag_header_len = 0; |
| 2056 | subflow_v6m_specific.rebuild_header = subflow_rebuild_header; |
| 2057 | |
| 2058 | tcpv6_prot_override = tcpv6_prot; |
| 2059 | tcpv6_prot_override.release_cb = tcp_release_cb_override; |
| 2060 | #endif |
| 2061 | |
| 2062 | mptcp_diag_subflow_init(&subflow_ulp_ops); |
| 2063 | |
| 2064 | if (tcp_register_ulp(&subflow_ulp_ops) != 0) |
| 2065 | panic("MPTCP: failed to register subflows to ULP\n"); |
| 2066 | } |