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
  30static void mptcp_subflow_ops_undo_override(struct sock *ssk);
  31
  32static void SUBFLOW_REQ_INC_STATS(struct request_sock *req,
  33				  enum linux_mptcp_mib_field field)
  34{
  35	MPTCP_INC_STATS(sock_net(req_to_sk(req)), field);
  36}
  37
  38static void subflow_req_destructor(struct request_sock *req)
  39{
  40	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
  41
  42	pr_debug("subflow_req=%p", subflow_req);
  43
  44	if (subflow_req->msk)
  45		sock_put((struct sock *)subflow_req->msk);
  46
  47	mptcp_token_destroy_request(req);
  48	tcp_request_sock_ops.destructor(req);
  49}
  50
  51static 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
  62static bool mptcp_can_accept_new_subflow(const struct mptcp_sock *msk)
  63{
  64	return mptcp_is_fully_established((void *)msk) &&
  65	       READ_ONCE(msk->pm.accept_subflow);
 
 
  66}
  67
  68/* validate received token and create truncated hmac and nonce for SYN-ACK */
  69static void subflow_req_create_thmac(struct mptcp_subflow_request_sock *subflow_req)
  70{
  71	struct mptcp_sock *msk = subflow_req->msk;
  72	u8 hmac[SHA256_DIGEST_SIZE];
  73
  74	get_random_bytes(&subflow_req->local_nonce, sizeof(u32));
  75
  76	subflow_generate_hmac(msk->local_key, msk->remote_key,
 
  77			      subflow_req->local_nonce,
  78			      subflow_req->remote_nonce, hmac);
  79
  80	subflow_req->thmac = get_unaligned_be64(hmac);
  81}
  82
  83static struct mptcp_sock *subflow_token_join_request(struct request_sock *req)
  84{
  85	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
  86	struct mptcp_sock *msk;
  87	int local_id;
  88
  89	msk = mptcp_token_get_sock(sock_net(req_to_sk(req)), subflow_req->token);
  90	if (!msk) {
  91		SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINNOTOKEN);
  92		return NULL;
  93	}
  94
  95	local_id = mptcp_pm_get_local_id(msk, (struct sock_common *)req);
  96	if (local_id < 0) {
  97		sock_put((struct sock *)msk);
  98		return NULL;
  99	}
 100	subflow_req->local_id = local_id;
 
 101
 102	return msk;
 103}
 104
 105static void subflow_init_req(struct request_sock *req, const struct sock *sk_listener)
 106{
 107	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
 108
 109	subflow_req->mp_capable = 0;
 110	subflow_req->mp_join = 0;
 111	subflow_req->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk_listener));
 112	subflow_req->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk_listener));
 113	subflow_req->msk = NULL;
 114	mptcp_token_init_request(req);
 115}
 116
 117static bool subflow_use_different_sport(struct mptcp_sock *msk, const struct sock *sk)
 118{
 119	return inet_sk(sk)->inet_sport != inet_sk((struct sock *)msk)->inet_sport;
 120}
 121
 122static void subflow_add_reset_reason(struct sk_buff *skb, u8 reason)
 123{
 124	struct mptcp_ext *mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
 125
 126	if (mpext) {
 127		memset(mpext, 0, sizeof(*mpext));
 128		mpext->reset_reason = reason;
 129	}
 130}
 131
 
 
 
 
 
 
 
 132/* Init mptcp request socket.
 133 *
 134 * Returns an error code if a JOIN has failed and a TCP reset
 135 * should be sent.
 136 */
 137static int subflow_check_req(struct request_sock *req,
 138			     const struct sock *sk_listener,
 139			     struct sk_buff *skb)
 140{
 141	struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
 142	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
 143	struct mptcp_options_received mp_opt;
 
 144
 145	pr_debug("subflow_req=%p, listener=%p", subflow_req, listener);
 146
 147#ifdef CONFIG_TCP_MD5SIG
 148	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
 149	 * TCP option space.
 150	 */
 151	if (rcu_access_pointer(tcp_sk(sk_listener)->md5sig_info))
 
 152		return -EINVAL;
 
 153#endif
 154
 155	mptcp_get_options(sk_listener, skb, &mp_opt);
 156
 157	if (mp_opt.mp_capable) {
 
 
 158		SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
 159
 160		if (mp_opt.mp_join)
 
 
 161			return 0;
 162	} else if (mp_opt.mp_join) {
 163		SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINSYNRX);
 
 
 
 
 
 164	}
 165
 166	if (mp_opt.mp_capable && listener->request_mptcp) {
 167		int err, retries = MPTCP_TOKEN_MAX_RETRIES;
 168
 169		subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
 170again:
 171		do {
 172			get_random_bytes(&subflow_req->local_key, sizeof(subflow_req->local_key));
 173		} while (subflow_req->local_key == 0);
 174
 175		if (unlikely(req->syncookie)) {
 176			mptcp_crypto_key_sha(subflow_req->local_key,
 177					     &subflow_req->token,
 178					     &subflow_req->idsn);
 179			if (mptcp_token_exists(subflow_req->token)) {
 180				if (retries-- > 0)
 181					goto again;
 182				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT);
 183			} else {
 184				subflow_req->mp_capable = 1;
 185			}
 186			return 0;
 187		}
 188
 189		err = mptcp_token_new_request(req);
 190		if (err == 0)
 191			subflow_req->mp_capable = 1;
 192		else if (retries-- > 0)
 193			goto again;
 194		else
 195			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_TOKENFALLBACKINIT);
 196
 197	} else if (mp_opt.mp_join && listener->request_mptcp) {
 198		subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq;
 199		subflow_req->mp_join = 1;
 200		subflow_req->backup = mp_opt.backup;
 201		subflow_req->remote_id = mp_opt.join_id;
 202		subflow_req->token = mp_opt.token;
 203		subflow_req->remote_nonce = mp_opt.nonce;
 204		subflow_req->msk = subflow_token_join_request(req);
 205
 206		/* Can't fall back to TCP in this case. */
 207		if (!subflow_req->msk) {
 208			subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
 209			return -EPERM;
 210		}
 211
 212		if (subflow_use_different_sport(subflow_req->msk, sk_listener)) {
 213			pr_debug("syn inet_sport=%d %d",
 214				 ntohs(inet_sk(sk_listener)->inet_sport),
 215				 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));
 216			if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {
 217				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX);
 
 218				return -EPERM;
 219			}
 220			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTSYNRX);
 221		}
 222
 223		subflow_req_create_thmac(subflow_req);
 224
 225		if (unlikely(req->syncookie)) {
 226			if (mptcp_can_accept_new_subflow(subflow_req->msk))
 227				subflow_init_req_cookie_join_save(subflow_req, skb);
 228			else
 229				return -EPERM;
 
 
 
 230		}
 231
 232		pr_debug("token=%u, remote_nonce=%u msk=%p", subflow_req->token,
 233			 subflow_req->remote_nonce, subflow_req->msk);
 234	}
 235
 236	return 0;
 237}
 238
 239int mptcp_subflow_init_cookie_req(struct request_sock *req,
 240				  const struct sock *sk_listener,
 241				  struct sk_buff *skb)
 242{
 243	struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk_listener);
 244	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
 245	struct mptcp_options_received mp_opt;
 
 246	int err;
 247
 248	subflow_init_req(req, sk_listener);
 249	mptcp_get_options(sk_listener, skb, &mp_opt);
 250
 251	if (mp_opt.mp_capable && mp_opt.mp_join)
 
 
 252		return -EINVAL;
 253
 254	if (mp_opt.mp_capable && listener->request_mptcp) {
 255		if (mp_opt.sndr_key == 0)
 256			return -EINVAL;
 257
 258		subflow_req->local_key = mp_opt.rcvr_key;
 259		err = mptcp_token_new_request(req);
 260		if (err)
 261			return err;
 262
 263		subflow_req->mp_capable = 1;
 264		subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
 265	} else if (mp_opt.mp_join && listener->request_mptcp) {
 266		if (!mptcp_token_join_cookie_init_state(subflow_req, skb))
 267			return -EINVAL;
 268
 269		subflow_req->mp_join = 1;
 270		subflow_req->ssn_offset = TCP_SKB_CB(skb)->seq - 1;
 271	}
 272
 273	return 0;
 274}
 275EXPORT_SYMBOL_GPL(mptcp_subflow_init_cookie_req);
 276
 
 
 
 
 
 
 
 
 
 
 277static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
 278					      struct sk_buff *skb,
 279					      struct flowi *fl,
 280					      struct request_sock *req)
 
 281{
 282	struct dst_entry *dst;
 283	int err;
 284
 285	tcp_rsk(req)->is_mptcp = 1;
 286	subflow_init_req(req, sk);
 287
 288	dst = tcp_request_sock_ipv4_ops.route_req(sk, skb, fl, req);
 289	if (!dst)
 290		return NULL;
 291
 292	err = subflow_check_req(req, sk, skb);
 293	if (err == 0)
 294		return dst;
 295
 296	dst_release(dst);
 297	if (!req->syncookie)
 298		tcp_request_sock_ops.send_reset(sk, skb);
 
 299	return NULL;
 300}
 301
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 302#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 
 
 
 
 
 
 
 
 
 
 
 
 
 303static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
 304					      struct sk_buff *skb,
 305					      struct flowi *fl,
 306					      struct request_sock *req)
 
 307{
 308	struct dst_entry *dst;
 309	int err;
 310
 311	tcp_rsk(req)->is_mptcp = 1;
 312	subflow_init_req(req, sk);
 313
 314	dst = tcp_request_sock_ipv6_ops.route_req(sk, skb, fl, req);
 315	if (!dst)
 316		return NULL;
 317
 318	err = subflow_check_req(req, sk, skb);
 319	if (err == 0)
 320		return dst;
 321
 322	dst_release(dst);
 323	if (!req->syncookie)
 324		tcp6_request_sock_ops.send_reset(sk, skb);
 
 325	return NULL;
 326}
 327#endif
 328
 329/* validate received truncated hmac and create hmac for third ACK */
 330static bool subflow_thmac_valid(struct mptcp_subflow_context *subflow)
 331{
 332	u8 hmac[SHA256_DIGEST_SIZE];
 333	u64 thmac;
 334
 335	subflow_generate_hmac(subflow->remote_key, subflow->local_key,
 336			      subflow->remote_nonce, subflow->local_nonce,
 337			      hmac);
 338
 339	thmac = get_unaligned_be64(hmac);
 340	pr_debug("subflow=%p, token=%u, thmac=%llu, subflow->thmac=%llu\n",
 341		 subflow, subflow->token,
 342		 (unsigned long long)thmac,
 343		 (unsigned long long)subflow->thmac);
 344
 345	return thmac == subflow->thmac;
 346}
 347
 348void mptcp_subflow_reset(struct sock *ssk)
 349{
 350	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 351	struct sock *sk = subflow->conn;
 352
 
 
 
 
 
 
 353	/* must hold: tcp_done() could drop last reference on parent */
 354	sock_hold(sk);
 355
 356	tcp_set_state(ssk, TCP_CLOSE);
 357	tcp_send_active_reset(ssk, GFP_ATOMIC);
 358	tcp_done(ssk);
 359	if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &mptcp_sk(sk)->flags) &&
 360	    schedule_work(&mptcp_sk(sk)->work))
 361		return; /* worker will put sk for us */
 362
 363	sock_put(sk);
 364}
 365
 366static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct sock *sk)
 367{
 368	return inet_sk(sk)->inet_dport != inet_sk((struct sock *)msk)->inet_dport;
 369}
 370
 371void __mptcp_set_connected(struct sock *sk)
 372{
 
 
 
 
 
 
 
 
 
 373	if (sk->sk_state == TCP_SYN_SENT) {
 374		inet_sk_state_store(sk, TCP_ESTABLISHED);
 
 
 
 
 
 375		sk->sk_state_change(sk);
 376	}
 377}
 378
 379static void mptcp_set_connected(struct sock *sk)
 
 
 380{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 381	mptcp_data_lock(sk);
 382	if (!sock_owned_by_user(sk))
 383		__mptcp_set_connected(sk);
 384	else
 385		set_bit(MPTCP_CONNECTED, &mptcp_sk(sk)->flags);
 
 
 
 
 
 
 
 
 
 
 
 386	mptcp_data_unlock(sk);
 387}
 388
 389static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 390{
 391	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 392	struct mptcp_options_received mp_opt;
 393	struct sock *parent = subflow->conn;
 
 394
 395	subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
 396
 397
 398	/* be sure no special action on any packet other than syn-ack */
 399	if (subflow->conn_finished)
 400		return;
 401
 402	mptcp_propagate_sndbuf(parent, sk);
 403	subflow->rel_write_seq = 1;
 404	subflow->conn_finished = 1;
 405	subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
 406	pr_debug("subflow=%p synack seq=%x", subflow, subflow->ssn_offset);
 407
 408	mptcp_get_options(sk, skb, &mp_opt);
 409	if (subflow->request_mptcp) {
 410		if (!mp_opt.mp_capable) {
 411			MPTCP_INC_STATS(sock_net(sk),
 412					MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
 413			mptcp_do_fallback(sk);
 414			pr_fallback(mptcp_sk(subflow->conn));
 415			goto fallback;
 416		}
 417
 418		if (mp_opt.csum_reqd)
 419			WRITE_ONCE(mptcp_sk(parent)->csum_enabled, true);
 420		if (mp_opt.deny_join_id0)
 421			WRITE_ONCE(mptcp_sk(parent)->pm.remote_deny_join_id0, true);
 422		subflow->mp_capable = 1;
 423		subflow->can_ack = 1;
 424		subflow->remote_key = mp_opt.sndr_key;
 425		pr_debug("subflow=%p, remote_key=%llu", subflow,
 426			 subflow->remote_key);
 427		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEACK);
 428		mptcp_finish_connect(sk);
 429		mptcp_set_connected(parent);
 
 430	} else if (subflow->request_join) {
 431		u8 hmac[SHA256_DIGEST_SIZE];
 432
 433		if (!mp_opt.mp_join) {
 434			subflow->reset_reason = MPTCP_RST_EMPTCP;
 435			goto do_reset;
 436		}
 437
 
 438		subflow->thmac = mp_opt.thmac;
 439		subflow->remote_nonce = mp_opt.nonce;
 440		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
 441			 subflow->thmac, subflow->remote_nonce);
 
 
 442
 443		if (!subflow_thmac_valid(subflow)) {
 444			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
 445			subflow->reset_reason = MPTCP_RST_EMPTCP;
 446			goto do_reset;
 447		}
 448
 449		if (!mptcp_finish_join(sk))
 450			goto do_reset;
 451
 452		subflow_generate_hmac(subflow->local_key, subflow->remote_key,
 453				      subflow->local_nonce,
 454				      subflow->remote_nonce,
 455				      hmac);
 456		memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);
 457
 458		subflow->mp_join = 1;
 459		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
 460
 461		if (subflow_use_different_dport(mptcp_sk(parent), sk)) {
 462			pr_debug("synack inet_dport=%d %d",
 
 
 
 463				 ntohs(inet_sk(sk)->inet_dport),
 464				 ntohs(inet_sk(parent)->inet_dport));
 465			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINPORTSYNACKRX);
 466		}
 467	} else if (mptcp_check_fallback(sk)) {
 
 
 
 468fallback:
 469		mptcp_rcv_space_init(mptcp_sk(parent), sk);
 470		mptcp_set_connected(parent);
 471	}
 472	return;
 473
 474do_reset:
 475	subflow->reset_transient = 0;
 476	mptcp_subflow_reset(sk);
 477}
 478
 479struct request_sock_ops mptcp_subflow_request_sock_ops;
 480EXPORT_SYMBOL_GPL(mptcp_subflow_request_sock_ops);
 481static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 482
 483static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 484{
 485	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 486
 487	pr_debug("subflow=%p", subflow);
 488
 489	/* Never answer to SYNs sent to broadcast or multicast */
 490	if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
 491		goto drop;
 492
 493	return tcp_conn_request(&mptcp_subflow_request_sock_ops,
 494				&subflow_request_sock_ipv4_ops,
 495				sk, skb);
 496drop:
 497	tcp_listendrop(sk);
 498	return 0;
 499}
 500
 
 
 
 
 
 
 501#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 502static struct tcp_request_sock_ops subflow_request_sock_ipv6_ops;
 503static struct inet_connection_sock_af_ops subflow_v6_specific;
 504static struct inet_connection_sock_af_ops subflow_v6m_specific;
 505static struct proto tcpv6_prot_override;
 
 506
 507static int subflow_v6_conn_request(struct sock *sk, struct sk_buff *skb)
 508{
 509	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 510
 511	pr_debug("subflow=%p", subflow);
 512
 513	if (skb->protocol == htons(ETH_P_IP))
 514		return subflow_v4_conn_request(sk, skb);
 515
 516	if (!ipv6_unicast_destination(skb))
 517		goto drop;
 518
 519	if (ipv6_addr_v4mapped(&ipv6_hdr(skb)->saddr)) {
 520		__IP6_INC_STATS(sock_net(sk), NULL, IPSTATS_MIB_INHDRERRORS);
 521		return 0;
 522	}
 523
 524	return tcp_conn_request(&mptcp_subflow_request_sock_ops,
 525				&subflow_request_sock_ipv6_ops, sk, skb);
 526
 527drop:
 528	tcp_listendrop(sk);
 529	return 0; /* don't send reset */
 530}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 531#endif
 532
 
 
 
 
 533/* validate hmac received in third ACK */
 534static bool subflow_hmac_valid(const struct request_sock *req,
 535			       const struct mptcp_options_received *mp_opt)
 536{
 537	const struct mptcp_subflow_request_sock *subflow_req;
 538	u8 hmac[SHA256_DIGEST_SIZE];
 539	struct mptcp_sock *msk;
 540
 541	subflow_req = mptcp_subflow_rsk(req);
 542	msk = subflow_req->msk;
 543	if (!msk)
 544		return false;
 545
 546	subflow_generate_hmac(msk->remote_key, msk->local_key,
 
 547			      subflow_req->remote_nonce,
 548			      subflow_req->local_nonce, hmac);
 549
 550	return !crypto_memneq(hmac, mp_opt->hmac, MPTCPOPT_HMAC_LEN);
 551}
 552
 553static void mptcp_sock_destruct(struct sock *sk)
 554{
 555	/* if new mptcp socket isn't accepted, it is free'd
 556	 * from the tcp listener sockets request queue, linked
 557	 * from req->sk.  The tcp socket is released.
 558	 * This calls the ULP release function which will
 559	 * also remove the mptcp socket, via
 560	 * sock_put(ctx->conn).
 561	 *
 562	 * Problem is that the mptcp socket will be in
 563	 * ESTABLISHED state and will not have the SOCK_DEAD flag.
 564	 * Both result in warnings from inet_sock_destruct.
 565	 */
 566	if ((1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)) {
 567		sk->sk_state = TCP_CLOSE;
 568		WARN_ON_ONCE(sk->sk_socket);
 569		sock_orphan(sk);
 570	}
 571
 572	mptcp_destroy_common(mptcp_sk(sk));
 573	inet_sock_destruct(sk);
 574}
 575
 576static void mptcp_force_close(struct sock *sk)
 577{
 578	/* the msk is not yet exposed to user-space */
 579	inet_sk_state_store(sk, TCP_CLOSE);
 580	sk_common_release(sk);
 581}
 582
 583static void subflow_ulp_fallback(struct sock *sk,
 584				 struct mptcp_subflow_context *old_ctx)
 585{
 586	struct inet_connection_sock *icsk = inet_csk(sk);
 587
 588	mptcp_subflow_tcp_fallback(sk, old_ctx);
 589	icsk->icsk_ulp_ops = NULL;
 590	rcu_assign_pointer(icsk->icsk_ulp_data, NULL);
 591	tcp_sk(sk)->is_mptcp = 0;
 592
 593	mptcp_subflow_ops_undo_override(sk);
 594}
 595
 596static void subflow_drop_ctx(struct sock *ssk)
 597{
 598	struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
 599
 600	if (!ctx)
 601		return;
 602
 603	subflow_ulp_fallback(ssk, ctx);
 604	if (ctx->conn)
 605		sock_put(ctx->conn);
 
 
 
 606
 607	kfree_rcu(ctx, rcu);
 608}
 609
 610void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow,
 611				     struct mptcp_options_received *mp_opt)
 
 612{
 613	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
 614
 615	subflow->remote_key = mp_opt->sndr_key;
 616	subflow->fully_established = 1;
 617	subflow->can_ack = 1;
 618	WRITE_ONCE(msk->fully_established, true);
 
 
 
 619}
 620
 621static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 622					  struct sk_buff *skb,
 623					  struct request_sock *req,
 624					  struct dst_entry *dst,
 625					  struct request_sock *req_unhash,
 626					  bool *own_req)
 627{
 628	struct mptcp_subflow_context *listener = mptcp_subflow_ctx(sk);
 629	struct mptcp_subflow_request_sock *subflow_req;
 630	struct mptcp_options_received mp_opt;
 631	bool fallback, fallback_is_fatal;
 632	struct sock *new_msk = NULL;
 
 633	struct sock *child;
 634
 635	pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
 636
 637	/* After child creation we must look for 'mp_capable' even when options
 638	 * are not parsed
 639	 */
 640	mp_opt.mp_capable = 0;
 641
 642	/* hopefully temporary handling for MP_JOIN+syncookie */
 643	subflow_req = mptcp_subflow_rsk(req);
 644	fallback_is_fatal = tcp_rsk(req)->is_mptcp && subflow_req->mp_join;
 645	fallback = !tcp_rsk(req)->is_mptcp;
 646	if (fallback)
 647		goto create_child;
 648
 649	/* if the sk is MP_CAPABLE, we try to fetch the client key */
 650	if (subflow_req->mp_capable) {
 651		/* we can receive and accept an in-window, out-of-order pkt,
 652		 * which may not carry the MP_CAPABLE opt even on mptcp enabled
 653		 * paths: always try to extract the peer key, and fallback
 654		 * for packets missing it.
 655		 * Even OoO DSS packets coming legitly after dropped or
 656		 * reordered MPC will cause fallback, but we don't have other
 657		 * options.
 658		 */
 659		mptcp_get_options(sk, skb, &mp_opt);
 660		if (!mp_opt.mp_capable) {
 
 661			fallback = true;
 662			goto create_child;
 663		}
 664
 665		new_msk = mptcp_sk_clone(listener->conn, &mp_opt, req);
 666		if (!new_msk)
 667			fallback = true;
 668	} else if (subflow_req->mp_join) {
 669		mptcp_get_options(sk, skb, &mp_opt);
 670		if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
 
 671		    !mptcp_can_accept_new_subflow(subflow_req->msk)) {
 672			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
 673			fallback = true;
 674		}
 675	}
 676
 677create_child:
 678	child = listener->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
 679						     req_unhash, own_req);
 680
 681	if (child && *own_req) {
 682		struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
 683
 684		tcp_rsk(req)->drop_req = false;
 685
 686		/* we need to fallback on ctx allocation failure and on pre-reqs
 687		 * checking above. In the latter scenario we additionally need
 688		 * to reset the context to non MPTCP status.
 689		 */
 690		if (!ctx || fallback) {
 691			if (fallback_is_fatal) {
 692				subflow_add_reset_reason(skb, MPTCP_RST_EMPTCP);
 693				goto dispose_child;
 694			}
 695
 696			subflow_drop_ctx(child);
 697			goto out;
 698		}
 699
 700		/* ssk inherits options of listener sk */
 701		ctx->setsockopt_seq = listener->setsockopt_seq;
 702
 703		if (ctx->mp_capable) {
 704			/* this can't race with mptcp_close(), as the msk is
 705			 * not yet exposted to user-space
 706			 */
 707			inet_sk_state_store((void *)new_msk, TCP_ESTABLISHED);
 708
 709			/* record the newly created socket as the first msk
 710			 * subflow, but don't link it yet into conn_list
 711			 */
 712			WRITE_ONCE(mptcp_sk(new_msk)->first, child);
 713
 714			/* new mpc subflow takes ownership of the newly
 715			 * created mptcp socket
 716			 */
 717			new_msk->sk_destruct = mptcp_sock_destruct;
 718			mptcp_sk(new_msk)->setsockopt_seq = ctx->setsockopt_seq;
 719			mptcp_pm_new_connection(mptcp_sk(new_msk), child, 1);
 720			mptcp_token_accept(subflow_req, mptcp_sk(new_msk));
 721			ctx->conn = new_msk;
 722			new_msk = NULL;
 723
 724			/* with OoO packets we can reach here without ingress
 725			 * mpc option
 726			 */
 727			if (mp_opt.mp_capable)
 728				mptcp_subflow_fully_established(ctx, &mp_opt);
 
 
 729		} else if (ctx->mp_join) {
 730			struct mptcp_sock *owner;
 731
 732			owner = subflow_req->msk;
 733			if (!owner) {
 734				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 735				goto dispose_child;
 736			}
 737
 738			/* move the msk reference ownership to the subflow */
 739			subflow_req->msk = NULL;
 740			ctx->conn = (struct sock *)owner;
 741
 742			if (subflow_use_different_sport(owner, sk)) {
 743				pr_debug("ack inet_sport=%d %d",
 744					 ntohs(inet_sk(sk)->inet_sport),
 745					 ntohs(inet_sk((struct sock *)owner)->inet_sport));
 746				if (!mptcp_pm_sport_in_anno_list(owner, sk)) {
 747					SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTACKRX);
 
 748					goto dispose_child;
 749				}
 750				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINPORTACKRX);
 751			}
 752
 753			if (!mptcp_finish_join(child))
 
 
 
 754				goto dispose_child;
 
 755
 756			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKRX);
 757			tcp_rsk(req)->drop_req = true;
 758		}
 759	}
 760
 761out:
 762	/* dispose of the left over mptcp master, if any */
 763	if (unlikely(new_msk))
 764		mptcp_force_close(new_msk);
 765
 766	/* check for expected invariant - should never trigger, just help
 767	 * catching eariler subtle bugs
 768	 */
 769	WARN_ON_ONCE(child && *own_req && tcp_sk(child)->is_mptcp &&
 770		     (!mptcp_subflow_ctx(child) ||
 771		      !mptcp_subflow_ctx(child)->conn));
 772	return child;
 773
 774dispose_child:
 775	subflow_drop_ctx(child);
 776	tcp_rsk(req)->drop_req = true;
 777	inet_csk_prepare_for_destroy_sock(child);
 778	tcp_done(child);
 779	req->rsk_ops->send_reset(sk, skb);
 
 780
 781	/* The last child reference will be released by the caller */
 782	return child;
 
 
 
 
 
 
 783}
 784
 785static struct inet_connection_sock_af_ops subflow_specific;
 786static struct proto tcp_prot_override;
 787
 788enum mapping_status {
 789	MAPPING_OK,
 790	MAPPING_INVALID,
 791	MAPPING_EMPTY,
 792	MAPPING_DATA_FIN,
 793	MAPPING_DUMMY
 
 
 794};
 795
 796static void dbg_bad_map(struct mptcp_subflow_context *subflow, u32 ssn)
 797{
 798	pr_debug("Bad mapping: ssn=%d map_seq=%d map_data_len=%d",
 799		 ssn, subflow->map_subflow_seq, subflow->map_data_len);
 800}
 801
 802static bool skb_is_fully_mapped(struct sock *ssk, struct sk_buff *skb)
 803{
 804	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 805	unsigned int skb_consumed;
 806
 807	skb_consumed = tcp_sk(ssk)->copied_seq - TCP_SKB_CB(skb)->seq;
 808	if (WARN_ON_ONCE(skb_consumed >= skb->len))
 
 809		return true;
 
 810
 811	return skb->len - skb_consumed <= subflow->map_data_len -
 812					  mptcp_subflow_get_map_offset(subflow);
 813}
 814
 815static bool validate_mapping(struct sock *ssk, struct sk_buff *skb)
 816{
 817	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 818	u32 ssn = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
 819
 820	if (unlikely(before(ssn, subflow->map_subflow_seq))) {
 821		/* Mapping covers data later in the subflow stream,
 822		 * currently unsupported.
 823		 */
 824		dbg_bad_map(subflow, ssn);
 825		return false;
 826	}
 827	if (unlikely(!before(ssn, subflow->map_subflow_seq +
 828				  subflow->map_data_len))) {
 829		/* Mapping does covers past subflow data, invalid */
 830		dbg_bad_map(subflow, ssn);
 831		return false;
 832	}
 833	return true;
 834}
 835
 836static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *skb,
 837					      bool csum_reqd)
 838{
 839	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 840	struct csum_pseudo_header header;
 841	u32 offset, seq, delta;
 842	__wsum csum;
 843	int len;
 844
 845	if (!csum_reqd)
 846		return MAPPING_OK;
 847
 848	/* mapping already validated on previous traversal */
 849	if (subflow->map_csum_len == subflow->map_data_len)
 850		return MAPPING_OK;
 851
 852	/* traverse the receive queue, ensuring it contains a full
 853	 * DSS mapping and accumulating the related csum.
 854	 * Preserve the accoumlate csum across multiple calls, to compute
 855	 * the csum only once
 856	 */
 857	delta = subflow->map_data_len - subflow->map_csum_len;
 858	for (;;) {
 859		seq = tcp_sk(ssk)->copied_seq + subflow->map_csum_len;
 860		offset = seq - TCP_SKB_CB(skb)->seq;
 861
 862		/* if the current skb has not been accounted yet, csum its contents
 863		 * up to the amount covered by the current DSS
 864		 */
 865		if (offset < skb->len) {
 866			__wsum csum;
 867
 868			len = min(skb->len - offset, delta);
 869			csum = skb_checksum(skb, offset, len, 0);
 870			subflow->map_data_csum = csum_block_add(subflow->map_data_csum, csum,
 871								subflow->map_csum_len);
 872
 873			delta -= len;
 874			subflow->map_csum_len += len;
 875		}
 876		if (delta == 0)
 877			break;
 878
 879		if (skb_queue_is_last(&ssk->sk_receive_queue, skb)) {
 880			/* if this subflow is closed, the partial mapping
 881			 * will be never completed; flush the pending skbs, so
 882			 * that subflow_sched_work_if_closed() can kick in
 883			 */
 884			if (unlikely(ssk->sk_state == TCP_CLOSE))
 885				while ((skb = skb_peek(&ssk->sk_receive_queue)))
 886					sk_eat_skb(ssk, skb);
 887
 888			/* not enough data to validate the csum */
 889			return MAPPING_EMPTY;
 890		}
 891
 892		/* the DSS mapping for next skbs will be validated later,
 893		 * when a get_mapping_status call will process such skb
 894		 */
 895		skb = skb->next;
 896	}
 897
 898	/* note that 'map_data_len' accounts only for the carried data, does
 899	 * not include the eventual seq increment due to the data fin,
 900	 * while the pseudo header requires the original DSS data len,
 901	 * including that
 902	 */
 903	header.data_seq = cpu_to_be64(subflow->map_seq);
 904	header.subflow_seq = htonl(subflow->map_subflow_seq);
 905	header.data_len = htons(subflow->map_data_len + subflow->map_data_fin);
 906	header.csum = 0;
 907
 908	csum = csum_partial(&header, sizeof(header), subflow->map_data_csum);
 909	if (unlikely(csum_fold(csum))) {
 910		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR);
 911		return subflow->mp_join ? MAPPING_INVALID : MAPPING_DUMMY;
 912	}
 913
 
 914	return MAPPING_OK;
 915}
 916
 917static enum mapping_status get_mapping_status(struct sock *ssk,
 918					      struct mptcp_sock *msk)
 919{
 920	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 921	bool csum_reqd = READ_ONCE(msk->csum_enabled);
 922	struct mptcp_ext *mpext;
 923	struct sk_buff *skb;
 924	u16 data_len;
 925	u64 map_seq;
 926
 927	skb = skb_peek(&ssk->sk_receive_queue);
 928	if (!skb)
 929		return MAPPING_EMPTY;
 930
 931	if (mptcp_check_fallback(ssk))
 932		return MAPPING_DUMMY;
 933
 934	mpext = mptcp_get_ext(skb);
 935	if (!mpext || !mpext->use_map) {
 936		if (!subflow->map_valid && !skb->len) {
 937			/* the TCP stack deliver 0 len FIN pkt to the receive
 938			 * queue, that is the only 0len pkts ever expected here,
 939			 * and we can admit no mapping only for 0 len pkts
 940			 */
 941			if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN))
 942				WARN_ONCE(1, "0len seq %d:%d flags %x",
 943					  TCP_SKB_CB(skb)->seq,
 944					  TCP_SKB_CB(skb)->end_seq,
 945					  TCP_SKB_CB(skb)->tcp_flags);
 946			sk_eat_skb(ssk, skb);
 947			return MAPPING_EMPTY;
 948		}
 949
 
 950		if (!subflow->map_valid)
 951			return MAPPING_INVALID;
 952
 953		goto validate_seq;
 954	}
 955
 956	trace_get_mapping_status(mpext);
 957
 958	data_len = mpext->data_len;
 959	if (data_len == 0) {
 
 960		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
 961		return MAPPING_INVALID;
 962	}
 963
 964	if (mpext->data_fin == 1) {
 
 
 965		if (data_len == 1) {
 966			bool updated = mptcp_update_rcv_data_fin(msk, mpext->data_seq,
 967								 mpext->dsn64);
 968			pr_debug("DATA_FIN with no payload seq=%llu", mpext->data_seq);
 969			if (subflow->map_valid) {
 970				/* A DATA_FIN might arrive in a DSS
 971				 * option before the previous mapping
 972				 * has been fully consumed. Continue
 973				 * handling the existing mapping.
 974				 */
 975				skb_ext_del(skb, SKB_EXT_MPTCP);
 976				return MAPPING_OK;
 977			} else {
 978				if (updated && schedule_work(&msk->work))
 979					sock_hold((struct sock *)msk);
 980
 981				return MAPPING_DATA_FIN;
 982			}
 983		} else {
 984			u64 data_fin_seq = mpext->data_seq + data_len - 1;
 985
 986			/* If mpext->data_seq is a 32-bit value, data_fin_seq
 987			 * must also be limited to 32 bits.
 988			 */
 989			if (!mpext->dsn64)
 990				data_fin_seq &= GENMASK_ULL(31, 0);
 991
 992			mptcp_update_rcv_data_fin(msk, data_fin_seq, mpext->dsn64);
 993			pr_debug("DATA_FIN with mapping seq=%llu dsn64=%d",
 994				 data_fin_seq, mpext->dsn64);
 995		}
 996
 
 
 
 
 
 
 
 
 
 
 
 
 997		/* Adjust for DATA_FIN using 1 byte of sequence space */
 998		data_len--;
 999	}
1000
1001	map_seq = mptcp_expand_seq(READ_ONCE(msk->ack_seq), mpext->data_seq, mpext->dsn64);
1002	WRITE_ONCE(mptcp_sk(subflow->conn)->use_64bit_ack, !!mpext->dsn64);
1003
1004	if (subflow->map_valid) {
1005		/* Allow replacing only with an identical map */
1006		if (subflow->map_seq == map_seq &&
1007		    subflow->map_subflow_seq == mpext->subflow_seq &&
1008		    subflow->map_data_len == data_len &&
1009		    subflow->map_csum_reqd == mpext->csum_reqd) {
1010			skb_ext_del(skb, SKB_EXT_MPTCP);
1011			goto validate_csum;
1012		}
1013
1014		/* If this skb data are fully covered by the current mapping,
1015		 * the new map would need caching, which is not supported
1016		 */
1017		if (skb_is_fully_mapped(ssk, skb)) {
1018			MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSNOMATCH);
1019			return MAPPING_INVALID;
1020		}
1021
1022		/* will validate the next map after consuming the current one */
1023		goto validate_csum;
1024	}
1025
1026	subflow->map_seq = map_seq;
1027	subflow->map_subflow_seq = mpext->subflow_seq;
1028	subflow->map_data_len = data_len;
1029	subflow->map_valid = 1;
1030	subflow->map_data_fin = mpext->data_fin;
1031	subflow->mpc_map = mpext->mpc_map;
1032	subflow->map_csum_reqd = mpext->csum_reqd;
1033	subflow->map_csum_len = 0;
1034	subflow->map_data_csum = csum_unfold(mpext->csum);
1035
1036	/* Cfr RFC 8684 Section 3.3.0 */
1037	if (unlikely(subflow->map_csum_reqd != csum_reqd))
1038		return MAPPING_INVALID;
1039
1040	pr_debug("new map seq=%llu subflow_seq=%u data_len=%u csum=%d:%u",
1041		 subflow->map_seq, subflow->map_subflow_seq,
1042		 subflow->map_data_len, subflow->map_csum_reqd,
1043		 subflow->map_data_csum);
1044
1045validate_seq:
1046	/* we revalidate valid mapping on new skb, because we must ensure
1047	 * the current skb is completely covered by the available mapping
1048	 */
1049	if (!validate_mapping(ssk, skb)) {
1050		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DSSTCPMISMATCH);
1051		return MAPPING_INVALID;
1052	}
1053
1054	skb_ext_del(skb, SKB_EXT_MPTCP);
1055
1056validate_csum:
1057	return validate_data_csum(ssk, skb, csum_reqd);
1058}
1059
1060static void mptcp_subflow_discard_data(struct sock *ssk, struct sk_buff *skb,
1061				       u64 limit)
1062{
1063	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1064	bool fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN;
1065	u32 incr;
 
 
 
 
 
1066
1067	incr = limit >= skb->len ? skb->len + fin : limit;
 
1068
1069	pr_debug("discarding=%d len=%d seq=%d", incr, skb->len,
1070		 subflow->map_subflow_seq);
1071	MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DUPDATA);
1072	tcp_sk(ssk)->copied_seq += incr;
 
 
1073	if (!before(tcp_sk(ssk)->copied_seq, TCP_SKB_CB(skb)->end_seq))
1074		sk_eat_skb(ssk, skb);
1075	if (mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len)
1076		subflow->map_valid = 0;
1077}
1078
1079/* sched mptcp worker to remove the subflow if no more data is pending */
1080static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk)
1081{
1082	struct sock *sk = (struct sock *)msk;
1083
1084	if (likely(ssk->sk_state != TCP_CLOSE))
 
 
1085		return;
1086
1087	if (skb_queue_empty(&ssk->sk_receive_queue) &&
1088	    !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags)) {
1089		sock_hold(sk);
1090		if (!schedule_work(&msk->work))
1091			sock_put(sk);
1092	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1093}
1094
1095static bool subflow_check_data_avail(struct sock *ssk)
1096{
1097	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1098	enum mapping_status status;
1099	struct mptcp_sock *msk;
1100	struct sk_buff *skb;
1101
1102	if (!skb_peek(&ssk->sk_receive_queue))
1103		WRITE_ONCE(subflow->data_avail, 0);
1104	if (subflow->data_avail)
1105		return true;
1106
1107	msk = mptcp_sk(subflow->conn);
1108	for (;;) {
1109		u64 ack_seq;
1110		u64 old_ack;
1111
1112		status = get_mapping_status(ssk, msk);
1113		trace_subflow_check_data_avail(status, skb_peek(&ssk->sk_receive_queue));
1114		if (unlikely(status == MAPPING_INVALID))
1115			goto fallback;
1116
1117		if (unlikely(status == MAPPING_DUMMY))
1118			goto fallback;
1119
1120		if (status != MAPPING_OK)
1121			goto no_data;
1122
1123		skb = skb_peek(&ssk->sk_receive_queue);
1124		if (WARN_ON_ONCE(!skb))
1125			goto no_data;
1126
1127		/* if msk lacks the remote key, this subflow must provide an
1128		 * MP_CAPABLE-based mapping
1129		 */
1130		if (unlikely(!READ_ONCE(msk->can_ack))) {
1131			if (!subflow->mpc_map)
1132				goto fallback;
1133			WRITE_ONCE(msk->remote_key, subflow->remote_key);
1134			WRITE_ONCE(msk->ack_seq, subflow->map_seq);
1135			WRITE_ONCE(msk->can_ack, true);
1136		}
1137
1138		old_ack = READ_ONCE(msk->ack_seq);
1139		ack_seq = mptcp_subflow_get_mapped_dsn(subflow);
1140		pr_debug("msk ack_seq=%llx subflow ack_seq=%llx", old_ack,
1141			 ack_seq);
1142		if (unlikely(before64(ack_seq, old_ack))) {
1143			mptcp_subflow_discard_data(ssk, skb, old_ack - ack_seq);
1144			continue;
1145		}
1146
1147		WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_DATA_AVAIL);
1148		break;
1149	}
1150	return true;
1151
1152no_data:
1153	subflow_sched_work_if_closed(msk, ssk);
1154	return false;
1155
1156fallback:
1157	/* RFC 8684 section 3.7. */
1158	if (subflow->mp_join || subflow->fully_established) {
1159		/* fatal protocol error, close the socket.
1160		 * subflow_error_report() will introduce the appropriate barriers
1161		 */
1162		ssk->sk_err = EBADMSG;
1163		tcp_set_state(ssk, TCP_CLOSE);
1164		subflow->reset_transient = 0;
1165		subflow->reset_reason = MPTCP_RST_EMPTCP;
1166		tcp_send_active_reset(ssk, GFP_ATOMIC);
1167		WRITE_ONCE(subflow->data_avail, 0);
1168		return false;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1169	}
1170
1171	__mptcp_do_fallback(msk);
1172	skb = skb_peek(&ssk->sk_receive_queue);
1173	subflow->map_valid = 1;
1174	subflow->map_seq = READ_ONCE(msk->ack_seq);
1175	subflow->map_data_len = skb->len;
1176	subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
1177	WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_DATA_AVAIL);
1178	return true;
1179}
1180
1181bool mptcp_subflow_data_available(struct sock *sk)
1182{
1183	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1184
1185	/* check if current mapping is still valid */
1186	if (subflow->map_valid &&
1187	    mptcp_subflow_get_map_offset(subflow) >= subflow->map_data_len) {
1188		subflow->map_valid = 0;
1189		WRITE_ONCE(subflow->data_avail, 0);
1190
1191		pr_debug("Done with mapping: seq=%u data_len=%u",
1192			 subflow->map_subflow_seq,
1193			 subflow->map_data_len);
1194	}
1195
1196	return subflow_check_data_avail(sk);
1197}
1198
1199/* If ssk has an mptcp parent socket, use the mptcp rcvbuf occupancy,
1200 * not the ssk one.
1201 *
1202 * In mptcp, rwin is about the mptcp-level connection data.
1203 *
1204 * Data that is still on the ssk rx queue can thus be ignored,
1205 * as far as mptcp peer is concerned that data is still inflight.
1206 * DSS ACK is updated when skb is moved to the mptcp rx queue.
1207 */
1208void mptcp_space(const struct sock *ssk, int *space, int *full_space)
1209{
1210	const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
1211	const struct sock *sk = subflow->conn;
1212
1213	*space = __mptcp_space(sk);
1214	*full_space = tcp_full_space(sk);
1215}
1216
1217void __mptcp_error_report(struct sock *sk)
1218{
1219	struct mptcp_subflow_context *subflow;
1220	struct mptcp_sock *msk = mptcp_sk(sk);
1221
1222	mptcp_for_each_subflow(msk, subflow) {
1223		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
1224		int err = sock_error(ssk);
1225
1226		if (!err)
1227			continue;
1228
1229		/* only propagate errors on fallen-back sockets or
1230		 * on MPC connect
1231		 */
1232		if (sk->sk_state != TCP_SYN_SENT && !__mptcp_check_fallback(msk))
1233			continue;
1234
1235		inet_sk_state_store(sk, inet_sk_state_load(ssk));
1236		sk->sk_err = -err;
1237
1238		/* This barrier is coupled with smp_rmb() in mptcp_poll() */
1239		smp_wmb();
1240		sk_error_report(sk);
1241		break;
1242	}
1243}
1244
1245static void subflow_error_report(struct sock *ssk)
1246{
1247	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1248
 
 
 
 
 
 
 
1249	mptcp_data_lock(sk);
1250	if (!sock_owned_by_user(sk))
1251		__mptcp_error_report(sk);
1252	else
1253		set_bit(MPTCP_ERROR_REPORT,  &mptcp_sk(sk)->flags);
1254	mptcp_data_unlock(sk);
1255}
1256
1257static void subflow_data_ready(struct sock *sk)
1258{
1259	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1260	u16 state = 1 << inet_sk_state_load(sk);
1261	struct sock *parent = subflow->conn;
1262	struct mptcp_sock *msk;
1263
 
 
1264	msk = mptcp_sk(parent);
1265	if (state & TCPF_LISTEN) {
1266		/* MPJ subflow are removed from accept queue before reaching here,
1267		 * avoid stray wakeups
1268		 */
1269		if (reqsk_queue_empty(&inet_csk(sk)->icsk_accept_queue))
1270			return;
1271
1272		set_bit(MPTCP_DATA_READY, &msk->flags);
1273		parent->sk_data_ready(parent);
1274		return;
1275	}
1276
1277	WARN_ON_ONCE(!__mptcp_check_fallback(msk) && !subflow->mp_capable &&
1278		     !subflow->mp_join && !(state & TCPF_CLOSE));
1279
1280	if (mptcp_subflow_data_available(sk))
1281		mptcp_data_ready(parent, sk);
1282	else if (unlikely(sk->sk_err))
 
 
 
 
 
 
 
1283		subflow_error_report(sk);
 
1284}
1285
1286static void subflow_write_space(struct sock *ssk)
1287{
1288	struct sock *sk = mptcp_subflow_ctx(ssk)->conn;
1289
1290	mptcp_propagate_sndbuf(sk, ssk);
1291	mptcp_write_space(sk);
1292}
1293
1294static struct inet_connection_sock_af_ops *
1295subflow_default_af_ops(struct sock *sk)
1296{
1297#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1298	if (sk->sk_family == AF_INET6)
1299		return &subflow_v6_specific;
1300#endif
1301	return &subflow_specific;
1302}
1303
1304#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1305void mptcpv6_handle_mapped(struct sock *sk, bool mapped)
1306{
1307	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1308	struct inet_connection_sock *icsk = inet_csk(sk);
1309	struct inet_connection_sock_af_ops *target;
1310
1311	target = mapped ? &subflow_v6m_specific : subflow_default_af_ops(sk);
1312
1313	pr_debug("subflow=%p family=%d ops=%p target=%p mapped=%d",
1314		 subflow, sk->sk_family, icsk->icsk_af_ops, target, mapped);
1315
1316	if (likely(icsk->icsk_af_ops == target))
1317		return;
1318
1319	subflow->icsk_af_ops = icsk->icsk_af_ops;
1320	icsk->icsk_af_ops = target;
1321}
1322#endif
1323
1324void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
1325			 struct sockaddr_storage *addr,
1326			 unsigned short family)
1327{
1328	memset(addr, 0, sizeof(*addr));
1329	addr->ss_family = family;
1330	if (addr->ss_family == AF_INET) {
1331		struct sockaddr_in *in_addr = (struct sockaddr_in *)addr;
1332
1333		if (info->family == AF_INET)
1334			in_addr->sin_addr = info->addr;
1335#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1336		else if (ipv6_addr_v4mapped(&info->addr6))
1337			in_addr->sin_addr.s_addr = info->addr6.s6_addr32[3];
1338#endif
1339		in_addr->sin_port = info->port;
1340	}
1341#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1342	else if (addr->ss_family == AF_INET6) {
1343		struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)addr;
1344
1345		if (info->family == AF_INET)
1346			ipv6_addr_set_v4mapped(info->addr.s_addr,
1347					       &in6_addr->sin6_addr);
1348		else
1349			in6_addr->sin6_addr = info->addr6;
1350		in6_addr->sin6_port = info->port;
1351	}
1352#endif
1353}
1354
1355int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
1356			    const struct mptcp_addr_info *remote,
1357			    u8 flags, int ifindex)
1358{
1359	struct mptcp_sock *msk = mptcp_sk(sk);
1360	struct mptcp_subflow_context *subflow;
 
1361	struct sockaddr_storage addr;
1362	int remote_id = remote->id;
1363	int local_id = loc->id;
1364	struct socket *sf;
1365	struct sock *ssk;
1366	u32 remote_token;
1367	int addrlen;
1368	int err;
1369
 
1370	if (!mptcp_is_fully_established(sk))
1371		return -ENOTCONN;
1372
1373	err = mptcp_subflow_create_socket(sk, &sf);
1374	if (err)
1375		return err;
 
 
 
 
1376
1377	ssk = sf->sk;
1378	subflow = mptcp_subflow_ctx(ssk);
1379	do {
1380		get_random_bytes(&subflow->local_nonce, sizeof(u32));
1381	} while (!subflow->local_nonce);
1382
1383	if (!local_id) {
1384		err = mptcp_pm_get_local_id(msk, (struct sock_common *)ssk);
1385		if (err < 0)
1386			goto failed;
1387
1388		local_id = err;
 
 
 
1389	}
1390
1391	subflow->remote_key = msk->remote_key;
1392	subflow->local_key = msk->local_key;
 
 
 
 
1393	subflow->token = msk->token;
1394	mptcp_info2sockaddr(loc, &addr, ssk->sk_family);
1395
1396	addrlen = sizeof(struct sockaddr_in);
1397#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1398	if (addr.ss_family == AF_INET6)
1399		addrlen = sizeof(struct sockaddr_in6);
1400#endif
1401	ssk->sk_bound_dev_if = ifindex;
1402	err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
1403	if (err)
 
 
 
1404		goto failed;
 
1405
1406	mptcp_crypto_key_sha(subflow->remote_key, &remote_token, NULL);
1407	pr_debug("msk=%p remote_token=%u local_id=%d remote_id=%d", msk,
1408		 remote_token, local_id, remote_id);
1409	subflow->remote_token = remote_token;
1410	subflow->local_id = local_id;
1411	subflow->remote_id = remote_id;
1412	subflow->request_join = 1;
1413	subflow->request_bkup = !!(flags & MPTCP_PM_ADDR_FLAG_BACKUP);
 
1414	mptcp_info2sockaddr(remote, &addr, ssk->sk_family);
1415
1416	mptcp_add_pending_subflow(msk, subflow);
1417	mptcp_sockopt_sync(msk, ssk);
1418	err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
1419	if (err && err != -EINPROGRESS)
 
 
 
1420		goto failed_unlink;
 
 
 
1421
1422	/* discard the subflow socket */
1423	mptcp_sock_graft(ssk, sk->sk_socket);
1424	iput(SOCK_INODE(sf));
1425	return err;
 
 
1426
1427failed_unlink:
1428	spin_lock_bh(&msk->join_list_lock);
1429	list_del(&subflow->node);
1430	spin_unlock_bh(&msk->join_list_lock);
1431	sock_put(mptcp_subflow_tcp_sock(subflow));
1432
1433failed:
1434	subflow->disposable = 1;
1435	sock_release(sf);
 
 
 
 
 
 
1436	return err;
1437}
1438
1439static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
1440{
1441#ifdef CONFIG_SOCK_CGROUP_DATA
1442	struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data,
1443				*child_skcd = &child->sk_cgrp_data;
1444
1445	/* only the additional subflows created by kworkers have to be modified */
1446	if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
1447	    cgroup_id(sock_cgroup_ptr(child_skcd))) {
1448#ifdef CONFIG_MEMCG
1449		struct mem_cgroup *memcg = parent->sk_memcg;
1450
1451		mem_cgroup_sk_free(child);
1452		if (memcg && css_tryget(&memcg->css))
1453			child->sk_memcg = memcg;
1454#endif /* CONFIG_MEMCG */
1455
1456		cgroup_sk_free(child_skcd);
1457		*child_skcd = *parent_skcd;
1458		cgroup_sk_clone(child_skcd);
1459	}
1460#endif /* CONFIG_SOCK_CGROUP_DATA */
1461}
1462
1463static void mptcp_subflow_ops_override(struct sock *ssk)
1464{
1465#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1466	if (ssk->sk_prot == &tcpv6_prot)
1467		ssk->sk_prot = &tcpv6_prot_override;
1468	else
1469#endif
1470		ssk->sk_prot = &tcp_prot_override;
1471}
1472
1473static void mptcp_subflow_ops_undo_override(struct sock *ssk)
1474{
1475#if IS_ENABLED(CONFIG_MPTCP_IPV6)
1476	if (ssk->sk_prot == &tcpv6_prot_override)
1477		ssk->sk_prot = &tcpv6_prot;
1478	else
1479#endif
1480		ssk->sk_prot = &tcp_prot;
1481}
1482int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock)
 
 
1483{
1484	struct mptcp_subflow_context *subflow;
1485	struct net *net = sock_net(sk);
1486	struct socket *sf;
1487	int err;
1488
1489	/* un-accepted server sockets can reach here - on bad configuration
1490	 * bail early to avoid greater trouble later
1491	 */
1492	if (unlikely(!sk->sk_socket))
1493		return -EINVAL;
1494
1495	err = sock_create_kern(net, sk->sk_family, SOCK_STREAM, IPPROTO_TCP,
1496			       &sf);
1497	if (err)
1498		return err;
1499
1500	lock_sock(sf->sk);
 
 
 
 
1501
1502	/* the newly created socket has to be in the same cgroup as its parent */
1503	mptcp_attach_cgroup(sk, sf->sk);
1504
1505	/* kernel sockets do not by default acquire net ref, but TCP timer
1506	 * needs it.
 
1507	 */
1508	sf->sk->sk_net_refcnt = 1;
1509	get_net(net);
1510#ifdef CONFIG_PROC_FS
1511	this_cpu_add(*net->core.sock_inuse, 1);
1512#endif
1513	err = tcp_set_ulp(sf->sk, "mptcp");
1514	release_sock(sf->sk);
 
1515
1516	if (err) {
1517		sock_release(sf);
1518		return err;
1519	}
1520
1521	/* the newly created socket really belongs to the owning MPTCP master
1522	 * socket, even if for additional subflows the allocation is performed
1523	 * by a kernel workqueue. Adjust inode references, so that the
1524	 * procfs/diag interaces really show this one belonging to the correct
1525	 * user.
1526	 */
1527	SOCK_INODE(sf)->i_ino = SOCK_INODE(sk->sk_socket)->i_ino;
1528	SOCK_INODE(sf)->i_uid = SOCK_INODE(sk->sk_socket)->i_uid;
1529	SOCK_INODE(sf)->i_gid = SOCK_INODE(sk->sk_socket)->i_gid;
1530
1531	subflow = mptcp_subflow_ctx(sf->sk);
1532	pr_debug("subflow=%p", subflow);
1533
1534	*new_sock = sf;
1535	sock_hold(sk);
1536	subflow->conn = sk;
1537	mptcp_subflow_ops_override(sf->sk);
1538
1539	return 0;
 
 
 
 
 
1540}
1541
1542static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
1543							gfp_t priority)
1544{
1545	struct inet_connection_sock *icsk = inet_csk(sk);
1546	struct mptcp_subflow_context *ctx;
1547
1548	ctx = kzalloc(sizeof(*ctx), priority);
1549	if (!ctx)
1550		return NULL;
1551
1552	rcu_assign_pointer(icsk->icsk_ulp_data, ctx);
1553	INIT_LIST_HEAD(&ctx->node);
1554	INIT_LIST_HEAD(&ctx->delegated_node);
1555
1556	pr_debug("subflow=%p", ctx);
1557
1558	ctx->tcp_sock = sk;
 
1559
1560	return ctx;
1561}
1562
1563static void __subflow_state_change(struct sock *sk)
1564{
1565	struct socket_wq *wq;
1566
1567	rcu_read_lock();
1568	wq = rcu_dereference(sk->sk_wq);
1569	if (skwq_has_sleeper(wq))
1570		wake_up_interruptible_all(&wq->wait);
1571	rcu_read_unlock();
1572}
1573
1574static bool subflow_is_done(const struct sock *sk)
1575{
1576	return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
1577}
1578
1579static void subflow_state_change(struct sock *sk)
1580{
1581	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
1582	struct sock *parent = subflow->conn;
 
1583
1584	__subflow_state_change(sk);
1585
 
1586	if (subflow_simultaneous_connect(sk)) {
1587		mptcp_propagate_sndbuf(parent, sk);
1588		mptcp_do_fallback(sk);
1589		mptcp_rcv_space_init(mptcp_sk(parent), sk);
1590		pr_fallback(mptcp_sk(parent));
1591		subflow->conn_finished = 1;
1592		mptcp_set_connected(parent);
1593	}
1594
1595	/* as recvmsg() does not acquire the subflow socket for ssk selection
1596	 * a fin packet carrying a DSS can be unnoticed if we don't trigger
1597	 * the data available machinery here.
1598	 */
1599	if (mptcp_subflow_data_available(sk))
1600		mptcp_data_ready(parent, sk);
1601	else if (unlikely(sk->sk_err))
1602		subflow_error_report(sk);
1603
1604	subflow_sched_work_if_closed(mptcp_sk(parent), sk);
1605
1606	if (__mptcp_check_fallback(mptcp_sk(parent)) &&
1607	    !subflow->rx_eof && subflow_is_done(sk)) {
1608		subflow->rx_eof = 1;
1609		mptcp_subflow_eof(parent);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1610	}
 
 
 
 
 
 
 
 
 
 
1611}
1612
1613static int subflow_ulp_init(struct sock *sk)
1614{
1615	struct inet_connection_sock *icsk = inet_csk(sk);
1616	struct mptcp_subflow_context *ctx;
1617	struct tcp_sock *tp = tcp_sk(sk);
1618	int err = 0;
1619
1620	/* disallow attaching ULP to a socket unless it has been
1621	 * created with sock_create_kern()
1622	 */
1623	if (!sk->sk_kern_sock) {
1624		err = -EOPNOTSUPP;
1625		goto out;
1626	}
1627
1628	ctx = subflow_create_ctx(sk, GFP_KERNEL);
1629	if (!ctx) {
1630		err = -ENOMEM;
1631		goto out;
1632	}
1633
1634	pr_debug("subflow=%p, family=%d", ctx, sk->sk_family);
1635
1636	tp->is_mptcp = 1;
1637	ctx->icsk_af_ops = icsk->icsk_af_ops;
1638	icsk->icsk_af_ops = subflow_default_af_ops(sk);
1639	ctx->tcp_data_ready = sk->sk_data_ready;
1640	ctx->tcp_state_change = sk->sk_state_change;
1641	ctx->tcp_write_space = sk->sk_write_space;
1642	ctx->tcp_error_report = sk->sk_error_report;
 
 
 
 
1643	sk->sk_data_ready = subflow_data_ready;
1644	sk->sk_write_space = subflow_write_space;
1645	sk->sk_state_change = subflow_state_change;
1646	sk->sk_error_report = subflow_error_report;
1647out:
1648	return err;
1649}
1650
1651static void subflow_ulp_release(struct sock *ssk)
1652{
1653	struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(ssk);
1654	bool release = true;
1655	struct sock *sk;
1656
1657	if (!ctx)
1658		return;
1659
1660	sk = ctx->conn;
1661	if (sk) {
1662		/* if the msk has been orphaned, keep the ctx
1663		 * alive, will be freed by __mptcp_close_ssk(),
1664		 * when the subflow is still unaccepted
1665		 */
1666		release = ctx->disposable || list_empty(&ctx->node);
 
 
 
 
 
 
 
1667		sock_put(sk);
1668	}
1669
1670	mptcp_subflow_ops_undo_override(ssk);
1671	if (release)
1672		kfree_rcu(ctx, rcu);
1673}
1674
1675static void subflow_ulp_clone(const struct request_sock *req,
1676			      struct sock *newsk,
1677			      const gfp_t priority)
1678{
1679	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
1680	struct mptcp_subflow_context *old_ctx = mptcp_subflow_ctx(newsk);
1681	struct mptcp_subflow_context *new_ctx;
1682
1683	if (!tcp_rsk(req)->is_mptcp ||
1684	    (!subflow_req->mp_capable && !subflow_req->mp_join)) {
1685		subflow_ulp_fallback(newsk, old_ctx);
1686		return;
1687	}
1688
1689	new_ctx = subflow_create_ctx(newsk, priority);
1690	if (!new_ctx) {
1691		subflow_ulp_fallback(newsk, old_ctx);
1692		return;
1693	}
1694
1695	new_ctx->conn_finished = 1;
1696	new_ctx->icsk_af_ops = old_ctx->icsk_af_ops;
1697	new_ctx->tcp_data_ready = old_ctx->tcp_data_ready;
1698	new_ctx->tcp_state_change = old_ctx->tcp_state_change;
1699	new_ctx->tcp_write_space = old_ctx->tcp_write_space;
1700	new_ctx->tcp_error_report = old_ctx->tcp_error_report;
1701	new_ctx->rel_write_seq = 1;
1702	new_ctx->tcp_sock = newsk;
1703
1704	if (subflow_req->mp_capable) {
1705		/* see comments in subflow_syn_recv_sock(), MPTCP connection
1706		 * is fully established only after we receive the remote key
1707		 */
1708		new_ctx->mp_capable = 1;
1709		new_ctx->local_key = subflow_req->local_key;
1710		new_ctx->token = subflow_req->token;
1711		new_ctx->ssn_offset = subflow_req->ssn_offset;
1712		new_ctx->idsn = subflow_req->idsn;
 
 
 
1713	} else if (subflow_req->mp_join) {
1714		new_ctx->ssn_offset = subflow_req->ssn_offset;
1715		new_ctx->mp_join = 1;
1716		new_ctx->fully_established = 1;
 
1717		new_ctx->backup = subflow_req->backup;
1718		new_ctx->local_id = subflow_req->local_id;
1719		new_ctx->remote_id = subflow_req->remote_id;
1720		new_ctx->token = subflow_req->token;
1721		new_ctx->thmac = subflow_req->thmac;
 
 
 
 
 
1722	}
1723}
1724
1725static void tcp_release_cb_override(struct sock *ssk)
1726{
1727	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 
1728
1729	if (mptcp_subflow_has_delegated_action(subflow))
1730		mptcp_subflow_process_delegated(ssk);
 
 
 
 
 
1731
1732	tcp_release_cb(ssk);
1733}
1734
 
 
 
 
 
 
 
 
 
 
 
1735static struct tcp_ulp_ops subflow_ulp_ops __read_mostly = {
1736	.name		= "mptcp",
1737	.owner		= THIS_MODULE,
1738	.init		= subflow_ulp_init,
1739	.release	= subflow_ulp_release,
1740	.clone		= subflow_ulp_clone,
1741};
1742
1743static int subflow_ops_init(struct request_sock_ops *subflow_ops)
1744{
1745	subflow_ops->obj_size = sizeof(struct mptcp_subflow_request_sock);
1746	subflow_ops->slab_name = "request_sock_subflow";
1747
1748	subflow_ops->slab = kmem_cache_create(subflow_ops->slab_name,
1749					      subflow_ops->obj_size, 0,
1750					      SLAB_ACCOUNT |
1751					      SLAB_TYPESAFE_BY_RCU,
1752					      NULL);
1753	if (!subflow_ops->slab)
1754		return -ENOMEM;
1755
1756	subflow_ops->destructor = subflow_req_destructor;
1757
1758	return 0;
1759}
1760
1761void __init mptcp_subflow_init(void)
1762{
1763	mptcp_subflow_request_sock_ops = tcp_request_sock_ops;
1764	if (subflow_ops_init(&mptcp_subflow_request_sock_ops) != 0)
1765		panic("MPTCP: failed to init subflow request sock ops\n");
 
 
 
1766
1767	subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
1768	subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
 
1769
1770	subflow_specific = ipv4_specific;
1771	subflow_specific.conn_request = subflow_v4_conn_request;
1772	subflow_specific.syn_recv_sock = subflow_syn_recv_sock;
1773	subflow_specific.sk_rx_dst_set = subflow_finish_connect;
 
1774
1775	tcp_prot_override = tcp_prot;
1776	tcp_prot_override.release_cb = tcp_release_cb_override;
 
1777
1778#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1779	subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
1780	subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
 
1781
1782	subflow_v6_specific = ipv6_specific;
1783	subflow_v6_specific.conn_request = subflow_v6_conn_request;
1784	subflow_v6_specific.syn_recv_sock = subflow_syn_recv_sock;
1785	subflow_v6_specific.sk_rx_dst_set = subflow_finish_connect;
 
1786
1787	subflow_v6m_specific = subflow_v6_specific;
1788	subflow_v6m_specific.queue_xmit = ipv4_specific.queue_xmit;
1789	subflow_v6m_specific.send_check = ipv4_specific.send_check;
1790	subflow_v6m_specific.net_header_len = ipv4_specific.net_header_len;
1791	subflow_v6m_specific.mtu_reduced = ipv4_specific.mtu_reduced;
1792	subflow_v6m_specific.net_frag_header_len = 0;
1793
1794	tcpv6_prot_override = tcpv6_prot;
1795	tcpv6_prot_override.release_cb = tcp_release_cb_override;
 
1796#endif
1797
1798	mptcp_diag_subflow_init(&subflow_ulp_ops);
1799
1800	if (tcp_register_ulp(&subflow_ulp_ops) != 0)
1801		panic("MPTCP: failed to register subflows to ULP\n");
1802}