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
  21 /* MPTCP option subtypes */
  22 #define MPTCPOPT_MP_CAPABLE     0
  23 #define MPTCPOPT_MP_JOIN        1
  24 #define MPTCPOPT_DSS            2
  25 #define MPTCPOPT_ADD_ADDR       3
  26 #define MPTCPOPT_RM_ADDR        4
  27 #define MPTCPOPT_MP_PRIO        5
  28 #define MPTCPOPT_MP_FAIL        6
  29 #define MPTCPOPT_MP_FASTCLOSE   7
  30
  31 /* MPTCP suboption lengths */
  32 #define TCPOLEN_MPTCP_MPC_SYN           4
  33 #define TCPOLEN_MPTCP_MPC_SYNACK        12
  34 #define TCPOLEN_MPTCP_MPC_ACK           20
  35 #define TCPOLEN_MPTCP_MPC_ACK_DATA      22
  36 #define TCPOLEN_MPTCP_DSS_BASE          4
  37 #define TCPOLEN_MPTCP_DSS_ACK32         4
  38 #define TCPOLEN_MPTCP_DSS_ACK64         8
  39 #define TCPOLEN_MPTCP_DSS_MAP32         10
  40 #define TCPOLEN_MPTCP_DSS_MAP64         14
  41 #define TCPOLEN_MPTCP_DSS_CHECKSUM      2
  42
  43 /* MPTCP MP_CAPABLE flags */
  44 #define MPTCP_VERSION_MASK      (0x0F)
  45 #define MPTCP_CAP_CHECKSUM_REQD BIT(7)
  46 #define MPTCP_CAP_EXTENSIBILITY BIT(6)
  47 #define MPTCP_CAP_HMAC_SHA256   BIT(0)
  48 #define MPTCP_CAP_FLAG_MASK     (0x3F)
  49
  50 /* MPTCP DSS flags */
  51 #define MPTCP_DSS_DATA_FIN      BIT(4)
  52 #define MPTCP_DSS_DSN64         BIT(3)
  53 #define MPTCP_DSS_HAS_MAP       BIT(2)
  54 #define MPTCP_DSS_ACK64         BIT(1)
  55 #define MPTCP_DSS_HAS_ACK       BIT(0)
  56 #define MPTCP_DSS_FLAG_MASK     (0x1F)
  57
  58 /* MPTCP socket flags */
  59 #define MPTCP_DATA_READY        BIT(0)
  60 #define MPTCP_SEND_SPACE        BIT(1)
  61
  62 /* MPTCP connection sock */
  63 struct mptcp_sock {
  64         /* inet_connection_sock must be the first member */
  65         struct inet_connection_sock sk;
  66         u64             local_key;
  67         u64             remote_key;
  68         u64             write_seq;
  69         u64             ack_seq;
  70         u32             token;
  71         unsigned long   flags;
  72         bool            can_ack;
  73         struct list_head conn_list;
  74         struct skb_ext  *cached_ext;    /* for the next sendmsg */
  75         struct socket   *subflow; /* outgoing connect/listener/!mp_capable */
  76         struct sock     *first;
  77 };
  78
  79 #define mptcp_for_each_subflow(__msk, __subflow)                        \
  80         list_for_each_entry(__subflow, &((__msk)->conn_list), node)
  81
  82 static inline struct mptcp_sock *mptcp_sk(const struct sock *sk)
  83 {
  84         return (struct mptcp_sock *)sk;
  85 }
  86
  87 struct mptcp_subflow_request_sock {
  88         struct  tcp_request_sock sk;
  89         u16     mp_capable : 1,
  90                 mp_join : 1,
  91                 backup : 1,
  92                 remote_key_valid : 1;
  93         u64     local_key;
  94         u64     remote_key;
  95         u64     idsn;
  96         u32     token;
  97         u32     ssn_offset;
  98 };
  99
 100 static inline struct mptcp_subflow_request_sock *
 101 mptcp_subflow_rsk(const struct request_sock *rsk)
 102 {
 103         return (struct mptcp_subflow_request_sock *)rsk;
 104 }
 105
 106 /* MPTCP subflow context */
 107 struct mptcp_subflow_context {
 108         struct  list_head node;/* conn_list of subflows */
 109         u64     local_key;
 110         u64     remote_key;
 111         u64     idsn;
 112         u64     map_seq;
 113         u32     snd_isn;
 114         u32     token;
 115         u32     rel_write_seq;
 116         u32     map_subflow_seq;
 117         u32     ssn_offset;
 118         u32     map_data_len;
 119         u32     request_mptcp : 1,  /* send MP_CAPABLE */
 120                 mp_capable : 1,     /* remote is MPTCP capable */
 121                 fourth_ack : 1,     /* send initial DSS */
 122                 conn_finished : 1,
 123                 map_valid : 1,
 124                 mpc_map : 1,
 125                 data_avail : 1,
 126                 rx_eof : 1,
 127                 can_ack : 1;        /* only after processing the remote a key */
 128
 129         struct  sock *tcp_sock;     /* tcp sk backpointer */
 130         struct  sock *conn;         /* parent mptcp_sock */
 131         const   struct inet_connection_sock_af_ops *icsk_af_ops;
 132         void    (*tcp_data_ready)(struct sock *sk);
 133         void    (*tcp_state_change)(struct sock *sk);
 134         void    (*tcp_write_space)(struct sock *sk);
 135
 136         struct  rcu_head rcu;
 137 };
 138
 139 static inline struct mptcp_subflow_context *
 140 mptcp_subflow_ctx(const struct sock *sk)
 141 {
 142         struct inet_connection_sock *icsk = inet_csk(sk);
 143
 144         /* Use RCU on icsk_ulp_data only for sock diag code */
 145         return (__force struct mptcp_subflow_context *)icsk->icsk_ulp_data;
 146 }
 147
 148 static inline struct sock *
 149 mptcp_subflow_tcp_sock(const struct mptcp_subflow_context *subflow)
 150 {
 151         return subflow->tcp_sock;
 152 }
 153
 154 static inline u64
 155 mptcp_subflow_get_map_offset(const struct mptcp_subflow_context *subflow)
 156 {
 157         return tcp_sk(mptcp_subflow_tcp_sock(subflow))->copied_seq -
 158                       subflow->ssn_offset -
 159                       subflow->map_subflow_seq;
 160 }
 161
 162 static inline u64
 163 mptcp_subflow_get_mapped_dsn(const struct mptcp_subflow_context *subflow)
 164 {
 165         return subflow->map_seq + mptcp_subflow_get_map_offset(subflow);
 166 }
 167
 168 int mptcp_is_enabled(struct net *net);
 169 bool mptcp_subflow_data_available(struct sock *sk);
 170 void mptcp_subflow_init(void);
 171 int mptcp_subflow_create_socket(struct sock *sk, struct socket **new_sock);
 172
 173 static inline void mptcp_subflow_tcp_fallback(struct sock *sk,
 174                                               struct mptcp_subflow_context *ctx)
 175 {
 176         sk->sk_data_ready = ctx->tcp_data_ready;
 177         sk->sk_state_change = ctx->tcp_state_change;
 178         sk->sk_write_space = ctx->tcp_write_space;
 179
 180         inet_csk(sk)->icsk_af_ops = ctx->icsk_af_ops;
 181 }
 182
 183 extern const struct inet_connection_sock_af_ops ipv4_specific;
 184 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 185 extern const struct inet_connection_sock_af_ops ipv6_specific;
 186 #endif
 187
 188 void mptcp_proto_init(void);
 189 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 190 int mptcp_proto_v6_init(void);
 191 #endif
 192
 193 struct mptcp_read_arg {
 194         struct msghdr *msg;
 195 };
 196
 197 int mptcp_read_actor(read_descriptor_t *desc, struct sk_buff *skb,
 198                      unsigned int offset, size_t len);
 199
 200 void mptcp_get_options(const struct sk_buff *skb,
 201                        struct tcp_options_received *opt_rx);
 202
 203 void mptcp_finish_connect(struct sock *sk);
 204
 205 int mptcp_token_new_request(struct request_sock *req);
 206 void mptcp_token_destroy_request(u32 token);
 207 int mptcp_token_new_connect(struct sock *sk);
 208 int mptcp_token_new_accept(u32 token);
 209 void mptcp_token_update_accept(struct sock *sk, struct sock *conn);
 210 void mptcp_token_destroy(u32 token);
 211
 212 void mptcp_crypto_key_sha(u64 key, u32 *token, u64 *idsn);
 213 static inline void mptcp_crypto_key_gen_sha(u64 *key, u32 *token, u64 *idsn)
 214 {
 215         /* we might consider a faster version that computes the key as a
 216          * hash of some information available in the MPTCP socket. Use
 217          * random data at the moment, as it's probably the safest option
 218          * in case multiple sockets are opened in different namespaces at
 219          * the same time.
 220          */
 221         get_random_bytes(key, sizeof(u64));
 222         mptcp_crypto_key_sha(*key, token, idsn);
 223 }
 224
 225 void mptcp_crypto_hmac_sha(u64 key1, u64 key2, u32 nonce1, u32 nonce2,
 226                            void *hash_out);
 227
 228 static inline struct mptcp_ext *mptcp_get_ext(struct sk_buff *skb)
 229 {
 230         return (struct mptcp_ext *)skb_ext_find(skb, SKB_EXT_MPTCP);
 231 }
 232
 233 static inline bool before64(__u64 seq1, __u64 seq2)
 234 {
 235         return (__s64)(seq1 - seq2) < 0;
 236 }
 237
 238 #define after64(seq2, seq1)     before64(seq1, seq2)
 239
 240 #endif /* __MPTCP_PROTOCOL_H */