include/net/mptcp.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Multipath TCP
   4  *
   5  * Copyright (c) 2017 - 2019, Intel Corporation.
   6  */
   7
   8 #ifndef __NET_MPTCP_H
   9 #define __NET_MPTCP_H
  10
  11 #include <linux/skbuff.h>
  12 #include <linux/tcp.h>
  13 #include <linux/types.h>
  14
  15 /* MPTCP sk_buff extension data */
  16 struct mptcp_ext {
  17         u64             data_ack;
  18         u64             data_seq;
  19         u32             subflow_seq;
  20         u16             data_len;
  21         u8              use_map:1,
  22                         dsn64:1,
  23                         data_fin:1,
  24                         use_ack:1,
  25                         ack64:1,
  26                         mpc_map:1,
  27                         __unused:2;
  28         /* one byte hole */
  29 };
  30
  31 struct mptcp_out_options {
  32 #if IS_ENABLED(CONFIG_MPTCP)
  33         u16 suboptions;
  34         u64 sndr_key;
  35         u64 rcvr_key;
  36         struct mptcp_ext ext_copy;
  37 #endif
  38 };
  39
  40 #ifdef CONFIG_MPTCP
  41
  42 void mptcp_init(void);
  43
  44 static inline bool sk_is_mptcp(const struct sock *sk)
  45 {
  46         return tcp_sk(sk)->is_mptcp;
  47 }
  48
  49 static inline bool rsk_is_mptcp(const struct request_sock *req)
  50 {
  51         return tcp_rsk(req)->is_mptcp;
  52 }
  53
  54 void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr,
  55                         int opsize, struct tcp_options_received *opt_rx);
  56 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
  57                        unsigned int *size, struct mptcp_out_options *opts);
  58 void mptcp_rcv_synsent(struct sock *sk);
  59 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
  60                           struct mptcp_out_options *opts);
  61 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
  62                                unsigned int *size, unsigned int remaining,
  63                                struct mptcp_out_options *opts);
  64 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
  65                             struct tcp_options_received *opt_rx);
  66
  67 void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts);
  68
  69 /* move the skb extension owership, with the assumption that 'to' is
  70  * newly allocated
  71  */
  72 static inline void mptcp_skb_ext_move(struct sk_buff *to,
  73                                       struct sk_buff *from)
  74 {
  75         if (!skb_ext_exist(from, SKB_EXT_MPTCP))
  76                 return;
  77
  78         if (WARN_ON_ONCE(to->active_extensions))
  79                 skb_ext_put(to);
  80
  81         to->active_extensions = from->active_extensions;
  82         to->extensions = from->extensions;
  83         from->active_extensions = 0;
  84 }
  85
  86 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
  87                                      const struct mptcp_ext *from_ext)
  88 {
  89         /* MPTCP always clears the ext when adding it to the skb, so
  90          * holes do not bother us here
  91          */
  92         return !from_ext ||
  93                (to_ext && from_ext &&
  94                 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
  95 }
  96
  97 /* check if skbs can be collapsed.
  98  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
  99  * mapping, or if the extension of @to is the same as @from.
 100  * Collapsing is not possible if @to lacks an extension, but @from carries one.
 101  */
 102 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 103                                           const struct sk_buff *from)
 104 {
 105         return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
 106                                  skb_ext_find(from, SKB_EXT_MPTCP));
 107 }
 108
 109 #else
 110
 111 static inline void mptcp_init(void)
 112 {
 113 }
 114
 115 static inline bool sk_is_mptcp(const struct sock *sk)
 116 {
 117         return false;
 118 }
 119
 120 static inline bool rsk_is_mptcp(const struct request_sock *req)
 121 {
 122         return false;
 123 }
 124
 125 static inline void mptcp_parse_option(const struct sk_buff *skb,
 126                                       const unsigned char *ptr, int opsize,
 127                                       struct tcp_options_received *opt_rx)
 128 {
 129 }
 130
 131 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 132                                      unsigned int *size,
 133                                      struct mptcp_out_options *opts)
 134 {
 135         return false;
 136 }
 137
 138 static inline void mptcp_rcv_synsent(struct sock *sk)
 139 {
 140 }
 141
 142 static inline bool mptcp_synack_options(const struct request_sock *req,
 143                                         unsigned int *size,
 144                                         struct mptcp_out_options *opts)
 145 {
 146         return false;
 147 }
 148
 149 static inline bool mptcp_established_options(struct sock *sk,
 150                                              struct sk_buff *skb,
 151                                              unsigned int *size,
 152                                              unsigned int remaining,
 153                                              struct mptcp_out_options *opts)
 154 {
 155         return false;
 156 }
 157
 158 static inline void mptcp_incoming_options(struct sock *sk,
 159                                           struct sk_buff *skb,
 160                                           struct tcp_options_received *opt_rx)
 161 {
 162 }
 163
 164 static inline void mptcp_skb_ext_move(struct sk_buff *to,
 165                                       const struct sk_buff *from)
 166 {
 167 }
 168
 169 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 170                                           const struct sk_buff *from)
 171 {
 172         return true;
 173 }
 174
 175 #endif /* CONFIG_MPTCP */
 176
 177 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 178 int mptcpv6_init(void);
 179 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
 180 #elif IS_ENABLED(CONFIG_IPV6)
 181 static inline int mptcpv6_init(void) { return 0; }
 182 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
 183 #endif
 184
 185 #endif /* __NET_MPTCP_H */