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 93 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field) 94 { 95 return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) | 96 ((nib & 0xF) << 8) | field); 97 } 98 99 #define MPTCP_PM_MAX_ADDR 4 100 101 struct mptcp_addr_info { 102 sa_family_t family; 103 __be16 port; 104 u8 id; 105 union { 106 struct in_addr addr; 107 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 108 struct in6_addr addr6; 109 #endif 110 }; 111 }; 112 113 enum mptcp_pm_status { 114 MPTCP_PM_ADD_ADDR_RECEIVED, 115 MPTCP_PM_ESTABLISHED, 116 MPTCP_PM_SUBFLOW_ESTABLISHED, 117 }; 118 119 struct mptcp_pm_data { 120 struct mptcp_addr_info local; 121 struct mptcp_addr_info remote; 122 123 spinlock_t lock; /*protects the whole PM data */ 124 125 bool addr_signal; 126 bool server_side; 127 bool work_pending; 128 bool accept_addr; 129 bool accept_subflow; 130 u8 add_addr_signaled; 131 u8 add_addr_accepted; 132 u8 local_addr_used; 133 u8 subflows; 134 u8 add_addr_signal_max; 135 u8 add_addr_accept_max; 136 u8 local_addr_max; 137 u8 subflows_max; 138 u8 status; 139 140 struct work_struct work; 141 }; 142 143 struct mptcp_data_frag { 144 struct list_head list; 145 u64 data_seq; 146 int data_len; 147 int offset; 148 int overhead; 149 struct page *page; 150 }; 151 152 /* MPTCP connection sock */ 153 struct mptcp_sock { 154 /* inet_connection_sock must be the first member */ 155 struct inet_connection_sock sk; 156 u64 local_key; 157 u64 remote_key; 158 u64 write_seq; 159 u64 ack_seq; 160 atomic64_t snd_una; 161 unsigned long timer_ival; 162 u32 token; 163 unsigned long flags; 164 bool can_ack; 165 spinlock_t join_list_lock; 166 struct work_struct work; 167 struct list_head conn_list; 168 struct list_head rtx_queue; 169 struct list_head join_list; 170 struct skb_ext *cached_ext; /* for the next sendmsg */ 171 struct socket *subflow; /* outgoing connect/listener/!mp_capable */ 172 struct sock *first; 173 struct mptcp_pm_data pm; 174 }; 175 176 #define mptcp_for_each_subflow(__msk, __subflow) \ 177 list_for_each_entry(__subflow, &((__msk)->conn_list), node) 178 179 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk) 180 { 181 return (struct mptcp_sock *)sk; 182 } 183 184 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk) 185 { 186 struct mptcp_sock *msk = mptcp_sk(sk); 187 188 if (list_empty(&msk->rtx_queue)) 189 return NULL; 190 191 return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 192 } 193 194 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk) 195 { 196 struct mptcp_sock *msk = mptcp_sk(sk); 197 198 if (list_empty(&msk->rtx_queue)) 199 return NULL; 200 201 return list_first_entry(&msk->rtx_queue, struct mptcp_data_frag, list); 202 } 203 204 struct mptcp_subflow_request_sock { 205 struct tcp_request_sock sk; 206 u16 mp_capable : 1, 207 mp_join : 1, 208 backup : 1, 209 remote_key_valid : 1; 210 u8 local_id; 211 u8 remote_id; 212 u64 local_key; 213 u64 remote_key; 214 u64 idsn; 215 u32 token; 216 u32 ssn_offset; 217 u64 thmac; 218 u32 local_nonce; 219 u32 remote_nonce; 220 }; 221 222 static inline struct mptcp_subflow_request_sock * 223 mptcp_subflow_rsk(const struct request_sock *rsk) 224 { 225 return (struct mptcp_subflow_request_sock *)rsk; 226 } 227 228 /* MPTCP subflow context */ 229 struct mptcp_subflow_context { 230 struct list_head node;/* conn_list of subflows */ 231 u64 local_key; 232 u64 remote_key; 233 u64 idsn; 234 u64 map_seq; 235 u32 snd_isn; 236 u32 token; 237 u32 rel_write_seq; 238 u32 map_subflow_seq; 239 u32 ssn_offset; 240 u32 map_data_len; 241 u32 request_mptcp : 1, /* send MP_CAPABLE */ 242 request_join : 1, /* send MP_JOIN */ 243 request_bkup : 1, 244 mp_capable : 1, /* remote is MPTCP capable */ 245 mp_join : 1, /* remote is JOINing */ 246 fully_established : 1, /* path validated */ 247 pm_notified : 1, /* PM hook called for established status */ 248 conn_finished : 1, 249 map_valid : 1, 250 mpc_map : 1, 251 backup : 1, 252 data_avail : 1, 253 rx_eof : 1, 254 data_fin_tx_enable : 1, 255 can_ack : 1; /* only after processing the remote a key */ 256 u64 data_fin_tx_seq; 257 u32 remote_nonce; 258 u64 thmac; 259 u32 local_nonce; 260 u32 remote_token; 261 u8 hmac[MPTCPOPT_HMAC_LEN]; 262 u8 local_id; 263 u8 remote_id; 264 265 struct sock *tcp_sock; /* tcp sk backpointer */ 266 struct sock *conn; /* parent mptcp_sock */ 267 const struct inet_connection_sock_af_ops *icsk_af_ops; 268 void (*tcp_data_ready)(struct sock *sk); 269 void (*tcp_state_change)(struct sock *sk); 270 void (*tcp_write_space)(struct sock *sk); 271 272 struct rcu_head rcu; 273 }; 274 275 static inline struct mptcp_subflow_context * 276 mptcp_subflow_ctx(const struct sock *sk) 277 { 278 struct inet_connection_sock *icsk = inet_csk(sk); 279 280 /* Use RCU on icsk_ulp_data only for sock diag code */ 281 return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data; 282 } 283 284 static inline struct sock * 285 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow) 286 { 287 return subflow->tcp_sock; 288 } 289 290 static inline u64 291 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow) 292 { 293 return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq - 294 subflow->ssn_offset - 295 subflow->map_subflow_seq; 296 } 297 298 static inline u64 299 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow) 300 { 301 return subflow->map_seq + mptcp_subflow_get_map_offset(subflow); 302 } 303 304 int mptcp_is_enabled(struct net *net); 305 bool mptcp_subflow_data_available(struct sock *sk); 306 void mptcp_subflow_init(void); 307 308 /* called with sk socket lock held */ 309 int __mptcp_subflow_connect(struct sock *sk, int ifindex, 310 const struct mptcp_addr_info *loc, 311 const struct mptcp_addr_info *remote); 312 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock); 313 314 static inline void mptcp_subflow_tcp_fallback(struct sock *sk, 315 struct mptcp_subflow_context *ctx) 316 { 317 sk->sk_data_ready = ctx->tcp_data_ready; 318 sk->sk_state_change = ctx->tcp_state_change; 319 sk->sk_write_space = ctx->tcp_write_space; 320 321 inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops; 322 } 323 324 extern const struct inet_connection_sock_af_ops ipv4_specific; 325 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 326 extern const struct inet_connection_sock_af_ops ipv6_specific; 327 #endif 328 329 void mptcp_proto_init(void); 330 #if IS_ENABLED(CONFIG_MPTCP_IPV6) 331 int mptcp_proto_v6_init(void); 332 #endif 333 334 struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req); 335 void mptcp_get_options(const struct sk_buff *skb, 336 struct tcp_options_received *opt_rx); 337 338 void mptcp_finish_connect(struct sock *sk); 339 void mptcp_data_ready(struct sock *sk, struct sock *ssk); 340 bool mptcp_finish_join(struct sock *sk); 341 void mptcp_data_acked(struct sock *sk); 342 343 int mptcp_token_new_request(struct request_sock *req); 344 void mptcp_token_destroy_request(u32 token); 345 int mptcp_token_new_connect(struct sock *sk); 346 int mptcp_token_new_accept(u32 token, struct sock *conn); 347 struct mptcp_sock *mptcp_token_get_sock(u32 token); 348 void mptcp_token_destroy(u32 token); 349 350 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn); 351 static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn) 352 { 353 /* we might consider a faster version that computes the key as a 354 * hash of some information available in the MPTCP socket. Use 355 * random data at the moment, as it's probably the safest option 356 * in case multiple sockets are opened in different namespaces at 357 * the same time. 358 */ 359 get_random_bytes(key, sizeof(u64)); 360 mptcp_crypto_key_sha(*key, token, idsn); 361 } 362 363 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac); 364 365 void mptcp_pm_init(void); 366 void mptcp_pm_data_init(struct mptcp_sock *msk); 367 void mptcp_pm_close(struct mptcp_sock *msk); 368 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side); 369 void mptcp_pm_fully_established(struct mptcp_sock *msk); 370 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk); 371 void mptcp_pm_connection_closed(struct mptcp_sock *msk); 372 void mptcp_pm_subflow_established(struct mptcp_sock *msk, 373 struct mptcp_subflow_context *subflow); 374 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id); 375 void mptcp_pm_add_addr_received(struct mptcp_sock *msk, 376 const struct mptcp_addr_info *addr); 377 378 int mptcp_pm_announce_addr(struct mptcp_sock *msk, 379 const struct mptcp_addr_info *addr); 380 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id); 381 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 remote_id); 382 383 static inline bool mptcp_pm_should_signal(struct mptcp_sock *msk) 384 { 385 return READ_ONCE(msk->pm.addr_signal); 386 } 387 388 static inline unsigned int mptcp_add_addr_len(int family) 389 { 390 if (family == AF_INET) 391 return TCPOLEN_MPTCP_ADD_ADDR; 392 return TCPOLEN_MPTCP_ADD_ADDR6; 393 } 394 395 bool mptcp_pm_addr_signal(struct mptcp_sock *msk, unsigned int remaining, 396 struct mptcp_addr_info *saddr); 397 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 398 399 void mptcp_pm_nl_init(void); 400 void mptcp_pm_nl_data_init(struct mptcp_sock *msk); 401 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk); 402 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk); 403 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk); 404 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc); 405 406 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb) 407 { 408 return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP); 409 } 410 411 static inline bool before64(__u64 seq1, __u64 seq2) 412 { 413 return (__s64)(seq1 - seq2) < 0; 414 } 415 416 #define after64(seq2, seq1) before64(seq1, seq2) 417 418 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops); 419 420 #endif /* __MPTCP_PROTOCOL_H */ 421