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 struct seq_file;
  16
  17 /* MPTCP sk_buff extension data */
  18 struct mptcp_ext {
  19         union {
  20                 u64     data_ack;
  21                 u32     data_ack32;
  22         };
  23         u64             data_seq;
  24         u32             subflow_seq;
  25         u16             data_len;
  26         u8              use_map:1,
  27                         dsn64:1,
  28                         data_fin:1,
  29                         use_ack:1,
  30                         ack64:1,
  31                         mpc_map:1,
  32                         __unused:2;
  33         /* one byte hole */
  34 };
  35
  36 struct mptcp_out_options {
  37 #if IS_ENABLED(CONFIG_MPTCP)
  38         u16 suboptions;
  39         u64 sndr_key;
  40         u64 rcvr_key;
  41         union {
  42                 struct in_addr addr;
  43 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  44                 struct in6_addr addr6;
  45 #endif
  46         };
  47         u8 addr_id;
  48         u64 ahmac;
  49         u8 rm_id;
  50         u8 join_id;
  51         u8 backup;
  52         u32 nonce;
  53         u64 thmac;
  54         u32 token;
  55         u8 hmac[20];
  56         struct mptcp_ext ext_copy;
  57 #endif
  58 };
  59
  60 #ifdef CONFIG_MPTCP
  61 extern struct request_sock_ops mptcp_subflow_request_sock_ops;
  62
  63 void mptcp_init(void);
  64
  65 static inline bool sk_is_mptcp(const struct sock *sk)
  66 {
  67         return tcp_sk(sk)->is_mptcp;
  68 }
  69
  70 static inline bool rsk_is_mptcp(const struct request_sock *req)
  71 {
  72         return tcp_rsk(req)->is_mptcp;
  73 }
  74
  75 static inline bool rsk_drop_req(const struct request_sock *req)
  76 {
  77         return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
  78 }
  79
  80 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
  81 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
  82                        unsigned int *size, struct mptcp_out_options *opts);
  83 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
  84                           struct mptcp_out_options *opts);
  85 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
  86                                unsigned int *size, unsigned int remaining,
  87                                struct mptcp_out_options *opts);
  88 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
  89
  90 void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts);
  91
  92 /* move the skb extension owership, with the assumption that 'to' is
  93  * newly allocated
  94  */
  95 static inline void mptcp_skb_ext_move(struct sk_buff *to,
  96                                       struct sk_buff *from)
  97 {
  98         if (!skb_ext_exist(from, SKB_EXT_MPTCP))
  99                 return;
 100
 101         if (WARN_ON_ONCE(to->active_extensions))
 102                 skb_ext_put(to);
 103
 104         to->active_extensions = from->active_extensions;
 105         to->extensions = from->extensions;
 106         from->active_extensions = 0;
 107 }
 108
 109 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
 110                                      const struct mptcp_ext *from_ext)
 111 {
 112         /* MPTCP always clears the ext when adding it to the skb, so
 113          * holes do not bother us here
 114          */
 115         return !from_ext ||
 116                (to_ext && from_ext &&
 117                 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
 118 }
 119
 120 /* check if skbs can be collapsed.
 121  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
 122  * mapping, or if the extension of @to is the same as @from.
 123  * Collapsing is not possible if @to lacks an extension, but @from carries one.
 124  */
 125 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 126                                           const struct sk_buff *from)
 127 {
 128         return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
 129                                  skb_ext_find(from, SKB_EXT_MPTCP));
 130 }
 131
 132 void mptcp_seq_show(struct seq_file *seq);
 133 int mptcp_subflow_init_cookie_req(struct request_sock *req,
 134                                   const struct sock *sk_listener,
 135                                   struct sk_buff *skb);
 136 #else
 137
 138 static inline void mptcp_init(void)
 139 {
 140 }
 141
 142 static inline bool sk_is_mptcp(const struct sock *sk)
 143 {
 144         return false;
 145 }
 146
 147 static inline bool rsk_is_mptcp(const struct request_sock *req)
 148 {
 149         return false;
 150 }
 151
 152 static inline bool rsk_drop_req(const struct request_sock *req)
 153 {
 154         return false;
 155 }
 156
 157 static inline void mptcp_parse_option(const struct sk_buff *skb,
 158                                       const unsigned char *ptr, int opsize,
 159                                       struct tcp_options_received *opt_rx)
 160 {
 161 }
 162
 163 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 164                                      unsigned int *size,
 165                                      struct mptcp_out_options *opts)
 166 {
 167         return false;
 168 }
 169
 170 static inline bool mptcp_synack_options(const struct request_sock *req,
 171                                         unsigned int *size,
 172                                         struct mptcp_out_options *opts)
 173 {
 174         return false;
 175 }
 176
 177 static inline bool mptcp_established_options(struct sock *sk,
 178                                              struct sk_buff *skb,
 179                                              unsigned int *size,
 180                                              unsigned int remaining,
 181                                              struct mptcp_out_options *opts)
 182 {
 183         return false;
 184 }
 185
 186 static inline void mptcp_incoming_options(struct sock *sk,
 187                                           struct sk_buff *skb)
 188 {
 189 }
 190
 191 static inline void mptcp_skb_ext_move(struct sk_buff *to,
 192                                       const struct sk_buff *from)
 193 {
 194 }
 195
 196 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 197                                           const struct sk_buff *from)
 198 {
 199         return true;
 200 }
 201
 202 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
 203 static inline void mptcp_seq_show(struct seq_file *seq) { }
 204
 205 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
 206                                                 const struct sock *sk_listener,
 207                                                 struct sk_buff *skb)
 208 {
 209         return 0; /* TCP fallback */
 210 }
 211 #endif /* CONFIG_MPTCP */
 212
 213 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 214 int mptcpv6_init(void);
 215 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
 216 #elif IS_ENABLED(CONFIG_IPV6)
 217 static inline int mptcpv6_init(void) { return 0; }
 218 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
 219 #endif
 220
 221 #endif /* __NET_MPTCP_H */