net/mptcp/protocol.h

   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
  93 struct mptcp_options_received {
  94         u64     sndr_key;
  95         u64     rcvr_key;
  96         u64     data_ack;
  97         u64     data_seq;
  98         u32     subflow_seq;
  99         u16     data_len;
 100         u16     mp_capable : 1,
 101                 mp_join : 1,
 102                 dss : 1,
 103                 add_addr : 1,
 104                 rm_addr : 1,
 105                 family : 4,
 106                 echo : 1,
 107                 backup : 1;
 108         u32     token;
 109         u32     nonce;
 110         u64     thmac;
 111         u8      hmac[20];
 112         u8      join_id;
 113         u8      use_map:1,
 114                 dsn64:1,
 115                 data_fin:1,
 116                 use_ack:1,
 117                 ack64:1,
 118                 mpc_map:1,
 119                 __unused:2;
 120         u8      addr_id;
 121         u8      rm_id;
 122         union {
 123                 struct in_addr  addr;
 124 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 125                 struct in6_addr addr6;
 126 #endif
 127         };
 128         u64     ahmac;
 129         u16     port;
 130 };
 131
 132 static inline __be32 mptcp_option(u8 subopt, u8 len, u8 nib, u8 field)
 133 {
 134         return htonl((TCPOPT_MPTCP << 24) | (len << 16) | (subopt << 12) |
 135                      ((nib & 0xF) << 8) | field);
 136 }
 137
 138 #define MPTCP_PM_MAX_ADDR       4
 139
 140 struct mptcp_addr_info {
 141         sa_family_t             family;
 142         __be16                  port;
 143         u8                      id;
 144         union {
 145                 struct in_addr addr;
 146 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 147                 struct in6_addr addr6;
 148 #endif
 149         };
 150 };
 151
 152 enum mptcp_pm_status {
 153         MPTCP_PM_ADD_ADDR_RECEIVED,
 154         MPTCP_PM_ESTABLISHED,
 155         MPTCP_PM_SUBFLOW_ESTABLISHED,
 156 };
 157
 158 struct mptcp_pm_data {
 159         struct mptcp_addr_info local;
 160         struct mptcp_addr_info remote;
 161
 162         spinlock_t      lock;           /*protects the whole PM data */
 163
 164         bool            addr_signal;
 165         bool            server_side;
 166         bool            work_pending;
 167         bool            accept_addr;
 168         bool            accept_subflow;
 169         u8              add_addr_signaled;
 170         u8              add_addr_accepted;
 171         u8              local_addr_used;
 172         u8              subflows;
 173         u8              add_addr_signal_max;
 174         u8              add_addr_accept_max;
 175         u8              local_addr_max;
 176         u8              subflows_max;
 177         u8              status;
 178
 179         struct          work_struct work;
 180 };
 181
 182 struct mptcp_data_frag {
 183         struct list_head list;
 184         u64 data_seq;
 185         int data_len;
 186         int offset;
 187         int overhead;
 188         struct page *page;
 189 };
 190
 191 /* MPTCP connection sock */
 192 struct mptcp_sock {
 193         /* inet_connection_sock must be the first member */
 194         struct inet_connection_sock sk;
 195         u64             local_key;
 196         u64             remote_key;
 197         u64             write_seq;
 198         u64             ack_seq;
 199         atomic64_t      snd_una;
 200         unsigned long   timer_ival;
 201         u32             token;
 202         unsigned long   flags;
 203         bool            can_ack;
 204         spinlock_t      join_list_lock;
 205         struct work_struct work;
 206         struct list_head conn_list;
 207         struct list_head rtx_queue;
 208         struct list_head join_list;
 209         struct skb_ext  *cached_ext;    /* for the next sendmsg */
 210         struct socket   *subflow; /* outgoing connect/listener/!mp_capable */
 211         struct sock     *first;
 212         struct mptcp_pm_data    pm;
 213 };
 214
 215 #define mptcp_for_each_subflow(__msk, __subflow)                        \
 216         list_for_each_entry(__subflow, &((__msk)->conn_list), node)
 217
 218 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
 219 {
 220         return (struct mptcp_sock *)sk;
 221 }
 222
 223 static inline struct mptcp_data_frag *mptcp_rtx_tail(const struct sock *sk)
 224 {
 225         struct mptcp_sock *msk = mptcp_sk(sk);
 226
 227         if (list_empty(&msk->rtx_queue))
 228                 return NULL;
 229
 230         return list_last_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
 231 }
 232
 233 static inline struct mptcp_data_frag *mptcp_rtx_head(const struct sock *sk)
 234 {
 235         struct mptcp_sock *msk = mptcp_sk(sk);
 236
 237         if (list_empty(&msk->rtx_queue))
 238                 return NULL;
 239
 240         return list_first_entry(&msk->rtx_queue, struct mptcp_data_frag, list);
 241 }
 242
 243 struct mptcp_subflow_request_sock {
 244         struct  tcp_request_sock sk;
 245         u16     mp_capable : 1,
 246                 mp_join : 1,
 247                 backup : 1;
 248         u8      local_id;
 249         u8      remote_id;
 250         u64     local_key;
 251         u64     idsn;
 252         u32     token;
 253         u32     ssn_offset;
 254         u64     thmac;
 255         u32     local_nonce;
 256         u32     remote_nonce;
 257 };
 258
 259 static inline struct mptcp_subflow_request_sock *
 260 mptcp_subflow_rsk(const struct request_sock *rsk)
 261 {
 262         return (struct mptcp_subflow_request_sock *)rsk;
 263 }
 264
 265 /* MPTCP subflow context */
 266 struct mptcp_subflow_context {
 267         struct  list_head node;/* conn_list of subflows */
 268         u64     local_key;
 269         u64     remote_key;
 270         u64     idsn;
 271         u64     map_seq;
 272         u32     snd_isn;
 273         u32     token;
 274         u32     rel_write_seq;
 275         u32     map_subflow_seq;
 276         u32     ssn_offset;
 277         u32     map_data_len;
 278         u32     request_mptcp : 1,  /* send MP_CAPABLE */
 279                 request_join : 1,   /* send MP_JOIN */
 280                 request_bkup : 1,
 281                 mp_capable : 1,     /* remote is MPTCP capable */
 282                 mp_join : 1,        /* remote is JOINing */
 283                 fully_established : 1,      /* path validated */
 284                 pm_notified : 1,    /* PM hook called for established status */
 285                 conn_finished : 1,
 286                 map_valid : 1,
 287                 mpc_map : 1,
 288                 backup : 1,
 289                 data_avail : 1,
 290                 rx_eof : 1,
 291                 data_fin_tx_enable : 1,
 292                 can_ack : 1;        /* only after processing the remote a key */
 293         u64     data_fin_tx_seq;
 294         u32     remote_nonce;
 295         u64     thmac;
 296         u32     local_nonce;
 297         u32     remote_token;
 298         u8      hmac[MPTCPOPT_HMAC_LEN];
 299         u8      local_id;
 300         u8      remote_id;
 301
 302         struct  sock *tcp_sock;     /* tcp sk backpointer */
 303         struct  sock *conn;         /* parent mptcp_sock */
 304         const   struct inet_connection_sock_af_ops *icsk_af_ops;
 305         void    (*tcp_data_ready)(struct sock *sk);
 306         void    (*tcp_state_change)(struct sock *sk);
 307         void    (*tcp_write_space)(struct sock *sk);
 308
 309         struct  rcu_head rcu;
 310 };
 311
 312 static inline struct mptcp_subflow_context *
 313 mptcp_subflow_ctx(const struct sock *sk)
 314 {
 315         struct inet_connection_sock *icsk = inet_csk(sk);
 316
 317         /* Use RCU on icsk_ulp_data only for sock diag code */
 318         return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
 319 }
 320
 321 static inline struct sock *
 322 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
 323 {
 324         return subflow->tcp_sock;
 325 }
 326
 327 static inline u64
 328 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
 329 {
 330         return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
 331                       subflow->ssn_offset -
 332                       subflow->map_subflow_seq;
 333 }
 334
 335 static inline u64
 336 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
 337 {
 338         return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
 339 }
 340
 341 int mptcp_is_enabled(struct net *net);
 342 bool mptcp_subflow_data_available(struct sock *sk);
 343 void mptcp_subflow_init(void);
 344
 345 /* called with sk socket lock held */
 346 int __mptcp_subflow_connect(struct sock *sk, int ifindex,
 347                             const struct mptcp_addr_info *loc,
 348                             const struct mptcp_addr_info *remote);
 349 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
 350
 351 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
 352                                               struct mptcp_subflow_context *ctx)
 353 {
 354         sk->sk_data_ready = ctx->tcp_data_ready;
 355         sk->sk_state_change = ctx->tcp_state_change;
 356         sk->sk_write_space = ctx->tcp_write_space;
 357
 358         inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
 359 }
 360
 361 extern const struct inet_connection_sock_af_ops ipv4_specific;
 362 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 363 extern const struct inet_connection_sock_af_ops ipv6_specific;
 364 #endif
 365
 366 void mptcp_proto_init(void);
 367 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 368 int mptcp_proto_v6_init(void);
 369 #endif
 370
 371 struct sock *mptcp_sk_clone(const struct sock *sk,
 372                             const struct mptcp_options_received *mp_opt,
 373                             struct request_sock *req);
 374 void mptcp_get_options(const struct sk_buff *skb,
 375                        struct mptcp_options_received *mp_opt);
 376
 377 void mptcp_finish_connect(struct sock *sk);
 378 void mptcp_data_ready(struct sock *sk, struct sock *ssk);
 379 bool mptcp_finish_join(struct sock *sk);
 380 void mptcp_data_acked(struct sock *sk);
 381 void mptcp_subflow_eof(struct sock *sk);
 382
 383 int mptcp_token_new_request(struct request_sock *req);
 384 void mptcp_token_destroy_request(u32 token);
 385 int mptcp_token_new_connect(struct sock *sk);
 386 int mptcp_token_new_accept(u32 token, struct sock *conn);
 387 struct mptcp_sock *mptcp_token_get_sock(u32 token);
 388 void mptcp_token_destroy(u32 token);
 389
 390 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
 391 static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
 392 {
 393         /* we might consider a faster version that computes the key as a
 394          * hash of some information available in the MPTCP socket. Use
 395          * random data at the moment, as it's probably the safest option
 396          * in case multiple sockets are opened in different namespaces at
 397          * the same time.
 398          */
 399         get_random_bytes(key, sizeof(u64));
 400         mptcp_crypto_key_sha(*key, token, idsn);
 401 }
 402
 403 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u8 *msg, int len, void *hmac);
 404
 405 void mptcp_pm_init(void);
 406 void mptcp_pm_data_init(struct mptcp_sock *msk);
 407 void mptcp_pm_close(struct mptcp_sock *msk);
 408 void mptcp_pm_new_connection(struct mptcp_sock *msk, int server_side);
 409 void mptcp_pm_fully_established(struct mptcp_sock *msk);
 410 bool mptcp_pm_allow_new_subflow(struct mptcp_sock *msk);
 411 void mptcp_pm_connection_closed(struct mptcp_sock *msk);
 412 void mptcp_pm_subflow_established(struct mptcp_sock *msk,
 413                                   struct mptcp_subflow_context *subflow);
 414 void mptcp_pm_subflow_closed(struct mptcp_sock *msk, u8 id);
 415 void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
 416                                 const struct mptcp_addr_info *addr);
 417
 418 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 419                            const struct mptcp_addr_info *addr);
 420 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id);
 421 int mptcp_pm_remove_subflow(struct mptcp_sock *msk, u8 remote_id);
 422
 423 static inline bool mptcp_pm_should_signal(struct mptcp_sock *msk)
 424 {
 425         return READ_ONCE(msk->pm.addr_signal);
 426 }
 427
 428 static inline unsigned int mptcp_add_addr_len(int family)
 429 {
 430         if (family == AF_INET)
 431                 return TCPOLEN_MPTCP_ADD_ADDR;
 432         return TCPOLEN_MPTCP_ADD_ADDR6;
 433 }
 434
 435 bool mptcp_pm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 436                           struct mptcp_addr_info *saddr);
 437 int mptcp_pm_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 438
 439 void mptcp_pm_nl_init(void);
 440 void mptcp_pm_nl_data_init(struct mptcp_sock *msk);
 441 void mptcp_pm_nl_fully_established(struct mptcp_sock *msk);
 442 void mptcp_pm_nl_subflow_established(struct mptcp_sock *msk);
 443 void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk);
 444 int mptcp_pm_nl_get_local_id(struct mptcp_sock *msk, struct sock_common *skc);
 445
 446 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
 447 {
 448         return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
 449 }
 450
 451 static inline bool before64(__u64 seq1, __u64 seq2)
 452 {
 453         return (__s64)(seq1 - seq2) < 0;
 454 }
 455
 456 #define after64(seq2, seq1)     before64(seq1, seq2)
 457
 458 void mptcp_diag_subflow_init(struct tcp_ulp_ops *ops);
 459
 460 #endif /* __MPTCP_PROTOCOL_H */