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_HMAC_LEN 20 85 #define MPTCP_ADDR_IPVERSION_4 4 86 #define MPTCP_ADDR_IPVERSION_6 6 87 88 /* MPTCP socket flags */ 89 #define MPTCP_DATA_READY 0 90 #define MPTCP_SEND_SPACE 1 91 #define MPTCP_WORK_RTX 2 92 #define MPTCP_WORK_EOF 3 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 #define MPTCP_PM_MAX_ADDR 4 140 141 struct mptcp_addr_info { 142 sa_family_t family; 143 __be16 port; 144 u8 id; 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_ESTABLISHED, 156 MPTCP_PM_SUBFLOW_ESTABLISHED, 157 }; 158 159 struct mptcp_pm_data { 160 struct mptcp_addr_info local; 161 struct mptcp_addr_info remote; 162 163 spinlock_t lock; /*protects the whole PM data */ 164 165 bool addr_signal; 166 bool server_side; 167 bool work_pending; 168 bool accept_addr; 169 bool accept_subflow; 170 u8 add_addr_signaled; 171 u8 add_addr_accepted; 172 u8 local_addr_used; 173 u8 subflows; 174 u8 add_addr_signal_max; 175 u8 add_addr_accept_max; 176 u8 local_addr_max; 177 u8 subflows_max; 178 u8 status; 179 180 struct work_struct work; 181 }; 182 183 struct mptcp_data_frag { 184 struct list_head list; 185 u64 data_seq; 186 int data_len; 187 int offset; 188 int overhead; 189 struct page *page; 190 }; 191 192 /* MPTCP connection sock */ 193 struct mptcp_sock { 194 /* inet_connection_sock must be the first member */ 195 struct inet_connection_sock sk; 196 u64 local_key; 197 u64 remote_key; 198 u64 write_seq; 199 u64 ack_seq; 200 atomic64_t snd_una; 201 unsigned long timer_ival; 202 u32 token; 203 unsigned long flags; 204 bool can_ack; 205 spinlock_t join_list_lock; 206 struct work_struct work; 207 struct list_head conn_list; 208 struct list_head rtx_queue; 209 struct list_head join_list; 210 struct skb_ext *cached_ext; /* for the next sendmsg */ 211 struct socket *subflow; /* outgoing connect/listener/!mp_capable */ 212 struct sock *first; 213 struct mptcp_pm_data pm; 214 }; 215 216 #define mptcp_for_each_subflow(__msk, __subflow) \ 217 list_for_each_entry(__subflow, &((__msk)->conn_list), node) 218 219 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) 220 { 221 return (struct mptcp_sock *)sk; 222 } 223 224 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk) 225 { 226 struct mptcp_sock *msk = mptcp_sk(sk); 227 228 if (list_empty(&msk->rtx_queue)) 229 return NULL; 230 231 return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 232 } 233 234 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk) 235 { 236 struct mptcp_sock *msk = mptcp_sk(sk); 237 238 if (list_empty(&msk->rtx_queue)) 239 return NULL; 240 241 return list_first_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 242 } 243 244 struct mptcp_subflow_request_sock { 245 struct tcp_request_sock sk; 246 u16 mp_capable : 1, 247 mp_join : 1, 248 backup : 1; 249 u8 local_id; 250 u8 remote_id; 251 u64 local_key; 252 u64 idsn; 253 u32 token; 254 u32 ssn_offset; 255 u64 thmac; 256 u32 local_nonce; 257 u32 remote_nonce; 258 }; 259 260 static inline struct mptcp_subflow_request_sock * 261 mptcp_subflow_rsk(const struct request_sock *rsk) 262 { 263 return (struct mptcp_subflow_request_sock *)rsk; 264 } 265 266 /* MPTCP subflow context */ 267 struct mptcp_subflow_context { 268 struct list_head node;/* conn_list of subflows */ 269 u64 local_key; 270 u64 remote_key; 271 u64 idsn; 272 u64 map_seq; 273 u32 snd_isn; 274 u32 token; 275 u32 rel_write_seq; 276 u32 map_subflow_seq; 277 u32 ssn_offset; 278 u32 map_data_len; 279 u32 request_mptcp : 1, /* send MP_CAPABLE */ 280 request_join : 1, /* send MP_JOIN */ 281 request_bkup : 1, 282 mp_capable : 1, /* remote is MPTCP capable */ 283 mp_join : 1, /* remote is JOINing */ 284 fully_established : 1, /* path validated */ 285 pm_notified : 1, /* PM hook called for established status */ 286 conn_finished : 1, 287 map_valid : 1, 288 mpc_map : 1, 289 backup : 1, 290 data_avail : 1, 291 rx_eof : 1, 292 data_fin_tx_enable : 1, 293 can_ack : 1; /* only after processing the remote a key */ 294 u64 data_fin_tx_seq; 295 u32 remote_nonce; 296 u64 thmac; 297 u32 local_nonce; 298 u32 remote_token; 299 u8 hmac[MPTCPOPT_HMAC_LEN]; 300 u8 local_id; 301 u8 remote_id; 302 303 struct sock *tcp_sock; /* tcp sk backpointer */ 304 struct sock *conn; /* parent mptcp_sock */ 305 const struct inet_connection_sock_af_ops *icsk_af_ops; 306 void (*tcp_data_ready)(struct sock *sk); 307 void (*tcp_state_change)(struct sock *sk); 308 void (*tcp_write_space)(struct sock *sk); 309 310 struct rcu_head rcu; 311 }; 312 313 static inline struct mptcp_subflow_context * 314 mptcp_subflow_ctx(const struct sock *sk) 315 { 316 struct inet_connection_sock *icsk = inet_csk(sk); 317 318 /* Use RCU on icsk_ulp_data only for sock diag code */ 319 return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data; 320 } 321 322 static inline struct sock * 323 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) 324 { 325 return subflow->tcp_sock; 326 } 327 328 static inline u64 329 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow) 330 { 331 return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq - 332 subflow->ssn_offset - 333 subflow->map_subflow_seq; 334 } 335 336 static inline u64 337 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow) 338 { 339 return subflow->map_seq + mptcp_subflow_get_map_offset(subflow); 340 } 341 342 int mptcp_is_enabled(struct net *net); 343 bool mptcp_subflow_data_available(struct sock *sk); 344 void mptcp_subflow_init(void); 345 346 /* called with sk socket lock held */ 347 int __mptcp_subflow_connect(struct sock *sk, int ifindex, 348 const struct mptcp_addr_info *loc, 349 const struct mptcp_addr_info *remote); 350 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock); 351 352 static inline void mptcp_subflow_tcp_fallback(struct sock *sk, 353 struct mptcp_subflow_context *ctx) 354 { 355 sk->sk_data_ready = ctx->tcp_data_ready; 356 sk->sk_state_change = ctx->tcp_state_change; 357 sk->sk_write_space = ctx->tcp_write_space; 358 359 inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops; 360 } 361 362 extern const struct inet_connection_sock_af_ops ipv4_specific; 363 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 364 extern const struct inet_connection_sock_af_ops ipv6_specific; 365 #endif 366 367 void mptcp_proto_init(void); 368 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 369 int mptcp_proto_v6_init(void); 370 #endif 371 372 struct sock *mptcp_sk_clone(const struct sock *sk, 373 const struct mptcp_options_received *mp_opt, 374 struct request_sock *req); 375 void mptcp_get_options(const struct sk_buff *skb, 376 struct mptcp_options_received *mp_opt); 377 378 void mptcp_finish_connect(struct sock *sk); 379 void mptcp_data_ready(struct sock *sk, struct sock *ssk); 380 bool mptcp_finish_join(struct sock *sk); 381 void mptcp_data_acked(struct sock *sk); 382 void mptcp_subflow_eof(struct sock *sk); 383 384 int mptcp_token_new_request(struct request_sock *req); 385 void mptcp_token_destroy_request(u32 token); 386 int mptcp_token_new_connect(struct sock *sk); 387 int mptcp_token_new_accept(u32 token, struct sock *conn); 388 struct mptcp_sock *mptcp_token_get_sock(u32 token); 389 void mptcp_token_destroy(u32 token); 390 391 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn); 392 static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn) 393 { 394 /* we might consider a faster version that computes the key as a 395 * hash of some information available in the MPTCP socket. Use 396 * random data at the moment, as it's probably the safest option 397 * in case multiple sockets are opened in different namespaces at 398 * the same time. 399 */ 400 get_random_bytes(key, sizeof(u64)); 401 mptcp_crypto_key_sha(*key, token, idsn); 402 } 403 404 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac); 405 406 void mptcp_pm_init(void); 407 void mptcp_pm_data_init(struct mptcp_sock *msk); 408 void mptcp_pm_close(struct mptcp_sock *msk); 409 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side); 410 void mptcp_pm_fully_established(struct mptcp_sock *msk); 411 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk); 412 void mptcp_pm_connection_closed(struct mptcp_sock *msk); 413 void mptcp_pm_subflow_established(struct mptcp_sock *msk, 414 struct mptcp_subflow_context *subflow); 415 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id); 416 void mptcp_pm_add_addr_received(struct mptcp_sock *msk, 417 const struct mptcp_addr_info *addr); 418 419 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 420 const struct mptcp_addr_info *addr); 421 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id); 422 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 remote_id); 423 424 static inline bool mptcp_pm_should_signal(struct mptcp_sock *msk) 425 { 426 return READ_ONCE(msk->pm.addr_signal); 427 } 428 429 static inline unsigned int mptcp_add_addr_len(int family) 430 { 431 if (family == AF_INET) 432 return TCPOLEN_MPTCP_ADD_ADDR; 433 return TCPOLEN_MPTCP_ADD_ADDR6; 434 } 435 436 bool mptcp_pm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 437 struct mptcp_addr_info *saddr); 438 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 439 440 void mptcp_pm_nl_init(void); 441 void mptcp_pm_nl_data_init(struct mptcp_sock *msk); 442 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk); 443 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk); 444 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk); 445 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 446 447 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb) 448 { 449 return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP); 450 } 451 452 static inline bool before64(__u64 seq1, __u64 seq2) 453 { 454 return (__s64)(seq1 - seq2) < 0; 455 } 456 457 #define after64(seq2, seq1) before64(seq1, seq2) 458 459 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops); 460 461 #endif /* __MPTCP_PROTOCOL_H */ 462