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 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field) 95 { 96 return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) | 97 ((nib & 0xF) << 8) | field); 98 } 99 100 #define MPTCP_PM_MAX_ADDR 4 101 102 struct mptcp_addr_info { 103 sa_family_t family; 104 __be16 port; 105 u8 id; 106 union { 107 struct in_addr addr; 108 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 109 struct in6_addr addr6; 110 #endif 111 }; 112 }; 113 114 enum mptcp_pm_status { 115 MPTCP_PM_ADD_ADDR_RECEIVED, 116 MPTCP_PM_ESTABLISHED, 117 MPTCP_PM_SUBFLOW_ESTABLISHED, 118 }; 119 120 struct mptcp_pm_data { 121 struct mptcp_addr_info local; 122 struct mptcp_addr_info remote; 123 124 spinlock_t lock; /*protects the whole PM data */ 125 126 bool addr_signal; 127 bool server_side; 128 bool work_pending; 129 bool accept_addr; 130 bool accept_subflow; 131 u8 add_addr_signaled; 132 u8 add_addr_accepted; 133 u8 local_addr_used; 134 u8 subflows; 135 u8 add_addr_signal_max; 136 u8 add_addr_accept_max; 137 u8 local_addr_max; 138 u8 subflows_max; 139 u8 status; 140 141 struct work_struct work; 142 }; 143 144 struct mptcp_data_frag { 145 struct list_head list; 146 u64 data_seq; 147 int data_len; 148 int offset; 149 int overhead; 150 struct page *page; 151 }; 152 153 /* MPTCP connection sock */ 154 struct mptcp_sock { 155 /* inet_connection_sock must be the first member */ 156 struct inet_connection_sock sk; 157 u64 local_key; 158 u64 remote_key; 159 u64 write_seq; 160 u64 ack_seq; 161 atomic64_t snd_una; 162 unsigned long timer_ival; 163 u32 token; 164 unsigned long flags; 165 bool can_ack; 166 spinlock_t join_list_lock; 167 struct work_struct work; 168 struct list_head conn_list; 169 struct list_head rtx_queue; 170 struct list_head join_list; 171 struct skb_ext *cached_ext; /* for the next sendmsg */ 172 struct socket *subflow; /* outgoing connect/listener/!mp_capable */ 173 struct sock *first; 174 struct mptcp_pm_data pm; 175 }; 176 177 #define mptcp_for_each_subflow(__msk, __subflow) \ 178 list_for_each_entry(__subflow, &((__msk)->conn_list), node) 179 180 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) 181 { 182 return (struct mptcp_sock *)sk; 183 } 184 185 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk) 186 { 187 struct mptcp_sock *msk = mptcp_sk(sk); 188 189 if (list_empty(&msk->rtx_queue)) 190 return NULL; 191 192 return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 193 } 194 195 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk) 196 { 197 struct mptcp_sock *msk = mptcp_sk(sk); 198 199 if (list_empty(&msk->rtx_queue)) 200 return NULL; 201 202 return list_first_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 203 } 204 205 struct mptcp_subflow_request_sock { 206 struct tcp_request_sock sk; 207 u16 mp_capable : 1, 208 mp_join : 1, 209 backup : 1, 210 remote_key_valid : 1; 211 u8 local_id; 212 u8 remote_id; 213 u64 local_key; 214 u64 remote_key; 215 u64 idsn; 216 u32 token; 217 u32 ssn_offset; 218 u64 thmac; 219 u32 local_nonce; 220 u32 remote_nonce; 221 }; 222 223 static inline struct mptcp_subflow_request_sock * 224 mptcp_subflow_rsk(const struct request_sock *rsk) 225 { 226 return (struct mptcp_subflow_request_sock *)rsk; 227 } 228 229 /* MPTCP subflow context */ 230 struct mptcp_subflow_context { 231 struct list_head node;/* conn_list of subflows */ 232 u64 local_key; 233 u64 remote_key; 234 u64 idsn; 235 u64 map_seq; 236 u32 snd_isn; 237 u32 token; 238 u32 rel_write_seq; 239 u32 map_subflow_seq; 240 u32 ssn_offset; 241 u32 map_data_len; 242 u32 request_mptcp : 1, /* send MP_CAPABLE */ 243 request_join : 1, /* send MP_JOIN */ 244 request_bkup : 1, 245 mp_capable : 1, /* remote is MPTCP capable */ 246 mp_join : 1, /* remote is JOINing */ 247 fully_established : 1, /* path validated */ 248 pm_notified : 1, /* PM hook called for established status */ 249 conn_finished : 1, 250 map_valid : 1, 251 mpc_map : 1, 252 backup : 1, 253 data_avail : 1, 254 rx_eof : 1, 255 data_fin_tx_enable : 1, 256 can_ack : 1; /* only after processing the remote a key */ 257 u64 data_fin_tx_seq; 258 u32 remote_nonce; 259 u64 thmac; 260 u32 local_nonce; 261 u32 remote_token; 262 u8 hmac[MPTCPOPT_HMAC_LEN]; 263 u8 local_id; 264 u8 remote_id; 265 266 struct sock *tcp_sock; /* tcp sk backpointer */ 267 struct sock *conn; /* parent mptcp_sock */ 268 const struct inet_connection_sock_af_ops *icsk_af_ops; 269 void (*tcp_data_ready)(struct sock *sk); 270 void (*tcp_state_change)(struct sock *sk); 271 void (*tcp_write_space)(struct sock *sk); 272 273 struct rcu_head rcu; 274 }; 275 276 static inline struct mptcp_subflow_context * 277 mptcp_subflow_ctx(const struct sock *sk) 278 { 279 struct inet_connection_sock *icsk = inet_csk(sk); 280 281 /* Use RCU on icsk_ulp_data only for sock diag code */ 282 return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data; 283 } 284 285 static inline struct sock * 286 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) 287 { 288 return subflow->tcp_sock; 289 } 290 291 static inline u64 292 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow) 293 { 294 return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq - 295 subflow->ssn_offset - 296 subflow->map_subflow_seq; 297 } 298 299 static inline u64 300 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow) 301 { 302 return subflow->map_seq + mptcp_subflow_get_map_offset(subflow); 303 } 304 305 int mptcp_is_enabled(struct net *net); 306 bool mptcp_subflow_data_available(struct sock *sk); 307 void mptcp_subflow_init(void); 308 309 /* called with sk socket lock held */ 310 int __mptcp_subflow_connect(struct sock *sk, int ifindex, 311 const struct mptcp_addr_info *loc, 312 const struct mptcp_addr_info *remote); 313 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock); 314 315 static inline void mptcp_subflow_tcp_fallback(struct sock *sk, 316 struct mptcp_subflow_context *ctx) 317 { 318 sk->sk_data_ready = ctx->tcp_data_ready; 319 sk->sk_state_change = ctx->tcp_state_change; 320 sk->sk_write_space = ctx->tcp_write_space; 321 322 inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops; 323 } 324 325 extern const struct inet_connection_sock_af_ops ipv4_specific; 326 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 327 extern const struct inet_connection_sock_af_ops ipv6_specific; 328 #endif 329 330 void mptcp_proto_init(void); 331 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 332 int mptcp_proto_v6_init(void); 333 #endif 334 335 struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req); 336 void mptcp_get_options(const struct sk_buff *skb, 337 struct tcp_options_received *opt_rx); 338 339 void mptcp_finish_connect(struct sock *sk); 340 void mptcp_data_ready(struct sock *sk, struct sock *ssk); 341 bool mptcp_finish_join(struct sock *sk); 342 void mptcp_data_acked(struct sock *sk); 343 void mptcp_subflow_eof(struct sock *sk); 344 345 int mptcp_token_new_request(struct request_sock *req); 346 void mptcp_token_destroy_request(u32 token); 347 int mptcp_token_new_connect(struct sock *sk); 348 int mptcp_token_new_accept(u32 token, struct sock *conn); 349 struct mptcp_sock *mptcp_token_get_sock(u32 token); 350 void mptcp_token_destroy(u32 token); 351 352 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn); 353 static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn) 354 { 355 /* we might consider a faster version that computes the key as a 356 * hash of some information available in the MPTCP socket. Use 357 * random data at the moment, as it's probably the safest option 358 * in case multiple sockets are opened in different namespaces at 359 * the same time. 360 */ 361 get_random_bytes(key, sizeof(u64)); 362 mptcp_crypto_key_sha(*key, token, idsn); 363 } 364 365 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac); 366 367 void mptcp_pm_init(void); 368 void mptcp_pm_data_init(struct mptcp_sock *msk); 369 void mptcp_pm_close(struct mptcp_sock *msk); 370 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side); 371 void mptcp_pm_fully_established(struct mptcp_sock *msk); 372 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk); 373 void mptcp_pm_connection_closed(struct mptcp_sock *msk); 374 void mptcp_pm_subflow_established(struct mptcp_sock *msk, 375 struct mptcp_subflow_context *subflow); 376 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id); 377 void mptcp_pm_add_addr_received(struct mptcp_sock *msk, 378 const struct mptcp_addr_info *addr); 379 380 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 381 const struct mptcp_addr_info *addr); 382 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id); 383 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 remote_id); 384 385 static inline bool mptcp_pm_should_signal(struct mptcp_sock *msk) 386 { 387 return READ_ONCE(msk->pm.addr_signal); 388 } 389 390 static inline unsigned int mptcp_add_addr_len(int family) 391 { 392 if (family == AF_INET) 393 return TCPOLEN_MPTCP_ADD_ADDR; 394 return TCPOLEN_MPTCP_ADD_ADDR6; 395 } 396 397 bool mptcp_pm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 398 struct mptcp_addr_info *saddr); 399 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 400 401 void mptcp_pm_nl_init(void); 402 void mptcp_pm_nl_data_init(struct mptcp_sock *msk); 403 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk); 404 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk); 405 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk); 406 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 407 408 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb) 409 { 410 return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP); 411 } 412 413 static inline bool before64(__u64 seq1, __u64 seq2) 414 { 415 return (__s64)(seq1 - seq2) < 0; 416 } 417 418 #define after64(seq2, seq1) before64(seq1, seq2) 419 420 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops); 421 422 #endif /* __MPTCP_PROTOCOL_H */ 423