1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* Multipath TCP 3 * 4 * Copyright (c) 2017 - 2019, Intel Corporation. 5 */ 6 7 #ifndef __MPTCP_PROTOCOL_H 8 #define __MPTCP_PROTOCOL_H 9 10 #include <linux/random.h> 11 #include <net/tcp.h> 12 #include <net/inet_connection_sock.h> 13 14 #define MPTCP_SUPPORTED_VERSION 1 15 16 /* MPTCP option bits */ 17 #define OPTION_MPTCP_MPC_SYN BIT(0) 18 #define OPTION_MPTCP_MPC_SYNACK BIT(1) 19 #define OPTION_MPTCP_MPC_ACK BIT(2) 20 #define OPTION_MPTCP_MPJ_SYN BIT(3) 21 #define OPTION_MPTCP_MPJ_SYNACK BIT(4) 22 #define OPTION_MPTCP_MPJ_ACK BIT(5) 23 #define OPTION_MPTCP_ADD_ADDR BIT(6) 24 #define OPTION_MPTCP_ADD_ADDR6 BIT(7) 25 #define OPTION_MPTCP_RM_ADDR BIT(8) 26 27 /* MPTCP option subtypes */ 28 #define MPTCPOPT_MP_CAPABLE 0 29 #define MPTCPOPT_MP_JOIN 1 30 #define MPTCPOPT_DSS 2 31 #define MPTCPOPT_ADD_ADDR 3 32 #define MPTCPOPT_RM_ADDR 4 33 #define MPTCPOPT_MP_PRIO 5 34 #define MPTCPOPT_MP_FAIL 6 35 #define MPTCPOPT_MP_FASTCLOSE 7 36 37 /* MPTCP suboption lengths */ 38 #define TCPOLEN_MPTCP_MPC_SYN 4 39 #define TCPOLEN_MPTCP_MPC_SYNACK 12 40 #define TCPOLEN_MPTCP_MPC_ACK 20 41 #define TCPOLEN_MPTCP_MPC_ACK_DATA 22 42 #define TCPOLEN_MPTCP_MPJ_SYN 12 43 #define TCPOLEN_MPTCP_MPJ_SYNACK 16 44 #define TCPOLEN_MPTCP_MPJ_ACK 24 45 #define TCPOLEN_MPTCP_DSS_BASE 4 46 #define TCPOLEN_MPTCP_DSS_ACK32 4 47 #define TCPOLEN_MPTCP_DSS_ACK64 8 48 #define TCPOLEN_MPTCP_DSS_MAP32 10 49 #define TCPOLEN_MPTCP_DSS_MAP64 14 50 #define TCPOLEN_MPTCP_DSS_CHECKSUM 2 51 #define TCPOLEN_MPTCP_ADD_ADDR 16 52 #define TCPOLEN_MPTCP_ADD_ADDR_PORT 18 53 #define TCPOLEN_MPTCP_ADD_ADDR_BASE 8 54 #define TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT 10 55 #define TCPOLEN_MPTCP_ADD_ADDR6 28 56 #define TCPOLEN_MPTCP_ADD_ADDR6_PORT 30 57 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE 20 58 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT 22 59 #define TCPOLEN_MPTCP_PORT_LEN 2 60 #define TCPOLEN_MPTCP_RM_ADDR_BASE 4 61 62 /* MPTCP MP_JOIN flags */ 63 #define MPTCPOPT_BACKUP BIT(0) 64 #define MPTCPOPT_HMAC_LEN 20 65 #define MPTCPOPT_THMAC_LEN 8 66 67 /* MPTCP MP_CAPABLE flags */ 68 #define MPTCP_VERSION_MASK (0x0F) 69 #define MPTCP_CAP_CHECKSUM_REQD BIT(7) 70 #define MPTCP_CAP_EXTENSIBILITY BIT(6) 71 #define MPTCP_CAP_HMAC_SHA256 BIT(0) 72 #define MPTCP_CAP_FLAG_MASK (0x3F) 73 74 /* MPTCP DSS flags */ 75 #define MPTCP_DSS_DATA_FIN BIT(4) 76 #define MPTCP_DSS_DSN64 BIT(3) 77 #define MPTCP_DSS_HAS_MAP BIT(2) 78 #define MPTCP_DSS_ACK64 BIT(1) 79 #define MPTCP_DSS_HAS_ACK BIT(0) 80 #define MPTCP_DSS_FLAG_MASK (0x1F) 81 82 /* MPTCP ADD_ADDR flags */ 83 #define MPTCP_ADDR_ECHO BIT(0) 84 #define MPTCP_ADDR_IPVERSION_4 4 85 #define MPTCP_ADDR_IPVERSION_6 6 86 87 /* MPTCP socket flags */ 88 #define MPTCP_DATA_READY 0 89 #define MPTCP_SEND_SPACE 1 90 #define MPTCP_WORK_RTX 2 91 #define MPTCP_WORK_EOF 3 92 #define MPTCP_FALLBACK_DONE 4 93 94 struct mptcp_options_received { 95 u64 sndr_key; 96 u64 rcvr_key; 97 u64 data_ack; 98 u64 data_seq; 99 u32 subflow_seq; 100 u16 data_len; 101 u16 mp_capable : 1, 102 mp_join : 1, 103 dss : 1, 104 add_addr : 1, 105 rm_addr : 1, 106 family : 4, 107 echo : 1, 108 backup : 1; 109 u32 token; 110 u32 nonce; 111 u64 thmac; 112 u8 hmac[20]; 113 u8 join_id; 114 u8 use_map:1, 115 dsn64:1, 116 data_fin:1, 117 use_ack:1, 118 ack64:1, 119 mpc_map:1, 120 __unused:2; 121 u8 addr_id; 122 u8 rm_id; 123 union { 124 struct in_addr addr; 125 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 126 struct in6_addr addr6; 127 #endif 128 }; 129 u64 ahmac; 130 u16 port; 131 }; 132 133 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field) 134 { 135 return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) | 136 ((nib & 0xF) << 8) | field); 137 } 138 139 struct mptcp_addr_info { 140 sa_family_t family; 141 __be16 port; 142 u8 id; 143 u8 flags; 144 int ifindex; 145 union { 146 struct in_addr addr; 147 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 148 struct in6_addr addr6; 149 #endif 150 }; 151 }; 152 153 enum mptcp_pm_status { 154 MPTCP_PM_ADD_ADDR_RECEIVED, 155 MPTCP_PM_RM_ADDR_RECEIVED, 156 MPTCP_PM_ESTABLISHED, 157 MPTCP_PM_SUBFLOW_ESTABLISHED, 158 }; 159 160 struct mptcp_pm_data { 161 struct mptcp_addr_info local; 162 struct mptcp_addr_info remote; 163 struct list_head anno_list; 164 165 spinlock_t lock; /*protects the whole PM data */ 166 167 bool add_addr_signal; 168 bool rm_addr_signal; 169 bool server_side; 170 bool work_pending; 171 bool accept_addr; 172 bool accept_subflow; 173 bool add_addr_echo; 174 u8 add_addr_signaled; 175 u8 add_addr_accepted; 176 u8 local_addr_used; 177 u8 subflows; 178 u8 add_addr_signal_max; 179 u8 add_addr_accept_max; 180 u8 local_addr_max; 181 u8 subflows_max; 182 u8 status; 183 u8 rm_id; 184 }; 185 186 struct mptcp_data_frag { 187 struct list_head list; 188 u64 data_seq; 189 int data_len; 190 int offset; 191 int overhead; 192 struct page *page; 193 }; 194 195 /* MPTCP connection sock */ 196 struct mptcp_sock { 197 /* inet_connection_sock must be the first member */ 198 struct inet_connection_sock sk; 199 u64 local_key; 200 u64 remote_key; 201 u64 write_seq; 202 u64 ack_seq; 203 u64 rcv_data_fin_seq; 204 struct sock *last_snd; 205 int snd_burst; 206 atomic64_t snd_una; 207 unsigned long timer_ival; 208 u32 token; 209 unsigned long flags; 210 bool can_ack; 211 bool fully_established; 212 bool rcv_data_fin; 213 bool snd_data_fin_enable; 214 spinlock_t join_list_lock; 215 struct work_struct work; 216 struct sk_buff *ooo_last_skb; 217 struct rb_root out_of_order_queue; 218 struct list_head conn_list; 219 struct list_head rtx_queue; 220 struct list_head join_list; 221 struct skb_ext *cached_ext; /* for the next sendmsg */ 222 struct socket *subflow; /* outgoing connect/listener/!mp_capable */ 223 struct sock *first; 224 struct mptcp_pm_data pm; 225 struct { 226 u32 space; /* bytes copied in last measurement window */ 227 u32 copied; /* bytes copied in this measurement window */ 228 u64 time; /* start time of measurement window */ 229 u64 rtt_us; /* last maximum rtt of subflows */ 230 } rcvq_space; 231 }; 232 233 #define mptcp_for_each_subflow(__msk, __subflow) \ 234 list_for_each_entry(__subflow, &((__msk)->conn_list), node) 235 236 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) 237 { 238 return (struct mptcp_sock *)sk; 239 } 240 241 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk) 242 { 243 struct mptcp_sock *msk = mptcp_sk(sk); 244 245 if (list_empty(&msk->rtx_queue)) 246 return NULL; 247 248 return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 249 } 250 251 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk) 252 { 253 struct mptcp_sock *msk = mptcp_sk(sk); 254 255 return list_first_entry_or_null(&msk->rtx_queue, struct mptcp_data_frag, list); 256 } 257 258 struct mptcp_subflow_request_sock { 259 struct tcp_request_sock sk; 260 u16 mp_capable : 1, 261 mp_join : 1, 262 backup : 1; 263 u8 local_id; 264 u8 remote_id; 265 u64 local_key; 266 u64 idsn; 267 u32 token; 268 u32 ssn_offset; 269 u64 thmac; 270 u32 local_nonce; 271 u32 remote_nonce; 272 struct mptcp_sock *msk; 273 struct hlist_nulls_node token_node; 274 }; 275 276 static inline struct mptcp_subflow_request_sock * 277 mptcp_subflow_rsk(const struct request_sock *rsk) 278 { 279 return (struct mptcp_subflow_request_sock *)rsk; 280 } 281 282 enum mptcp_data_avail { 283 MPTCP_SUBFLOW_NODATA, 284 MPTCP_SUBFLOW_DATA_AVAIL, 285 MPTCP_SUBFLOW_OOO_DATA 286 }; 287 288 /* MPTCP subflow context */ 289 struct mptcp_subflow_context { 290 struct list_head node;/* conn_list of subflows */ 291 u64 local_key; 292 u64 remote_key; 293 u64 idsn; 294 u64 map_seq; 295 u32 snd_isn; 296 u32 token; 297 u32 rel_write_seq; 298 u32 map_subflow_seq; 299 u32 ssn_offset; 300 u32 map_data_len; 301 u32 request_mptcp : 1, /* send MP_CAPABLE */ 302 request_join : 1, /* send MP_JOIN */ 303 request_bkup : 1, 304 mp_capable : 1, /* remote is MPTCP capable */ 305 mp_join : 1, /* remote is JOINing */ 306 fully_established : 1, /* path validated */ 307 pm_notified : 1, /* PM hook called for established status */ 308 conn_finished : 1, 309 map_valid : 1, 310 mpc_map : 1, 311 backup : 1, 312 rx_eof : 1, 313 use_64bit_ack : 1, /* Set when we received a 64-bit DSN */ 314 can_ack : 1; /* only after processing the remote a key */ 315 enum mptcp_data_avail data_avail; 316 u32 remote_nonce; 317 u64 thmac; 318 u32 local_nonce; 319 u32 remote_token; 320 u8 hmac[MPTCPOPT_HMAC_LEN]; 321 u8 local_id; 322 u8 remote_id; 323 324 struct sock *tcp_sock; /* tcp sk backpointer */ 325 struct sock *conn; /* parent mptcp_sock */ 326 const struct inet_connection_sock_af_ops *icsk_af_ops; 327 void (*tcp_data_ready)(struct sock *sk); 328 void (*tcp_state_change)(struct sock *sk); 329 void (*tcp_write_space)(struct sock *sk); 330 331 struct rcu_head rcu; 332 }; 333 334 static inline struct mptcp_subflow_context * 335 mptcp_subflow_ctx(const struct sock *sk) 336 { 337 struct inet_connection_sock *icsk = inet_csk(sk); 338 339 /* Use RCU on icsk_ulp_data only for sock diag code */ 340 return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data; 341 } 342 343 static inline struct sock * 344 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) 345 { 346 return subflow->tcp_sock; 347 } 348 349 static inline u64 350 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow) 351 { 352 return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq - 353 subflow->ssn_offset - 354 subflow->map_subflow_seq; 355 } 356 357 static inline u64 358 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow) 359 { 360 return subflow->map_seq + mptcp_subflow_get_map_offset(subflow); 361 } 362 363 int mptcp_is_enabled(struct net *net); 364 void mptcp_subflow_fully_established(struct mptcp_subflow_context *subflow, 365 struct mptcp_options_received *mp_opt); 366 bool mptcp_subflow_data_available(struct sock *sk); 367 void __init mptcp_subflow_init(void); 368 void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how); 369 void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 370 struct mptcp_subflow_context *subflow, 371 long timeout); 372 373 /* called with sk socket lock held */ 374 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc, 375 const struct mptcp_addr_info *remote); 376 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock); 377 378 static inline void mptcp_subflow_tcp_fallback(struct sock *sk, 379 struct mptcp_subflow_context *ctx) 380 { 381 sk->sk_data_ready = ctx->tcp_data_ready; 382 sk->sk_state_change = ctx->tcp_state_change; 383 sk->sk_write_space = ctx->tcp_write_space; 384 385 inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops; 386 } 387 388 void __init mptcp_proto_init(void); 389 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 390 int __init mptcp_proto_v6_init(void); 391 #endif 392 393 struct sock *mptcp_sk_clone(const struct sock *sk, 394 const struct mptcp_options_received *mp_opt, 395 struct request_sock *req); 396 void mptcp_get_options(const struct sk_buff *skb, 397 struct mptcp_options_received *mp_opt); 398 399 void mptcp_finish_connect(struct sock *sk); 400 static inline bool mptcp_is_fully_established(struct sock *sk) 401 { 402 return inet_sk_state_load(sk) == TCP_ESTABLISHED && 403 READ_ONCE(mptcp_sk(sk)->fully_established); 404 } 405 void mptcp_rcv_space_init(struct mptcp_sock *msk, const struct sock *ssk); 406 void mptcp_data_ready(struct sock *sk, struct sock *ssk); 407 bool mptcp_finish_join(struct sock *sk); 408 void mptcp_data_acked(struct sock *sk); 409 void mptcp_subflow_eof(struct sock *sk); 410 bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq); 411 void mptcp_destroy_common(struct mptcp_sock *msk); 412 413 void __init mptcp_token_init(void); 414 static inline void mptcp_token_init_request(struct request_sock *req) 415 { 416 mptcp_subflow_rsk(req)->token_node.pprev = NULL; 417 } 418 419 int mptcp_token_new_request(struct request_sock *req); 420 void mptcp_token_destroy_request(struct request_sock *req); 421 int mptcp_token_new_connect(struct sock *sk); 422 void mptcp_token_accept(struct mptcp_subflow_request_sock *r, 423 struct mptcp_sock *msk); 424 bool mptcp_token_exists(u32 token); 425 struct mptcp_sock *mptcp_token_get_sock(u32 token); 426 struct mptcp_sock *mptcp_token_iter_next(const struct net *net, long *s_slot, 427 long *s_num); 428 void mptcp_token_destroy(struct mptcp_sock *msk); 429 430 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn); 431 432 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac); 433 434 void __init mptcp_pm_init(void); 435 void mptcp_pm_data_init(struct mptcp_sock *msk); 436 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side); 437 void mptcp_pm_fully_established(struct mptcp_sock *msk); 438 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk); 439 void mptcp_pm_connection_closed(struct mptcp_sock *msk); 440 void mptcp_pm_subflow_established(struct mptcp_sock *msk, 441 struct mptcp_subflow_context *subflow); 442 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id); 443 void mptcp_pm_add_addr_received(struct mptcp_sock *msk, 444 const struct mptcp_addr_info *addr); 445 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id); 446 void mptcp_pm_free_anno_list(struct mptcp_sock *msk); 447 struct mptcp_pm_add_entry * 448 mptcp_pm_del_add_timer(struct mptcp_sock *msk, 449 struct mptcp_addr_info *addr); 450 451 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 452 const struct mptcp_addr_info *addr, 453 bool echo); 454 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id); 455 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 local_id); 456 457 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk) 458 { 459 return READ_ONCE(msk->pm.add_addr_signal); 460 } 461 462 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk) 463 { 464 return READ_ONCE(msk->pm.rm_addr_signal); 465 } 466 467 static inline unsigned int mptcp_add_addr_len(int family) 468 { 469 if (family == AF_INET) 470 return TCPOLEN_MPTCP_ADD_ADDR; 471 return TCPOLEN_MPTCP_ADD_ADDR6; 472 } 473 474 bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 475 struct mptcp_addr_info *saddr, bool *echo); 476 bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 477 u8 *rm_id); 478 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 479 480 void __init mptcp_pm_nl_init(void); 481 void mptcp_pm_nl_data_init(struct mptcp_sock *msk); 482 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk); 483 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk); 484 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk); 485 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk); 486 void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, u8 rm_id); 487 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 488 489 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb) 490 { 491 return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP); 492 } 493 494 static inline bool before64(__u64 seq1, __u64 seq2) 495 { 496 return (__s64)(seq1 - seq2) < 0; 497 } 498 499 #define after64(seq2, seq1) before64(seq1, seq2) 500 501 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops); 502 503 static inline bool __mptcp_check_fallback(const struct mptcp_sock *msk) 504 { 505 return test_bit(MPTCP_FALLBACK_DONE, &msk->flags); 506 } 507 508 static inline bool mptcp_check_fallback(const struct sock *sk) 509 { 510 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 511 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 512 513 return __mptcp_check_fallback(msk); 514 } 515 516 static inline void __mptcp_do_fallback(struct mptcp_sock *msk) 517 { 518 if (test_bit(MPTCP_FALLBACK_DONE, &msk->flags)) { 519 pr_debug("TCP fallback already done (msk=%p)", msk); 520 return; 521 } 522 set_bit(MPTCP_FALLBACK_DONE, &msk->flags); 523 } 524 525 static inline void mptcp_do_fallback(struct sock *sk) 526 { 527 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 528 struct mptcp_sock *msk = mptcp_sk(subflow->conn); 529 530 __mptcp_do_fallback(msk); 531 } 532 533 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a) 534 535 static inline bool subflow_simultaneous_connect(struct sock *sk) 536 { 537 struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); 538 struct sock *parent = subflow->conn; 539 540 return sk->sk_state == TCP_ESTABLISHED && 541 !mptcp_sk(parent)->pm.server_side && 542 !subflow->conn_finished; 543 } 544 545 #ifdef CONFIG_SYN_COOKIES 546 void subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req, 547 struct sk_buff *skb); 548 bool mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req, 549 struct sk_buff *skb); 550 void __init mptcp_join_cookie_init(void); 551 #else 552 static inline void 553 subflow_init_req_cookie_join_save(const struct mptcp_subflow_request_sock *subflow_req, 554 struct sk_buff *skb) {} 555 static inline bool 556 mptcp_token_join_cookie_init_state(struct mptcp_subflow_request_sock *subflow_req, 557 struct sk_buff *skb) 558 { 559 return false; 560 } 561 562 static inline void mptcp_join_cookie_init(void) {} 563 #endif 564 565 #endif /* __MPTCP_PROTOCOL_H */ 566