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                         frozen:1,
  33                         reset_transient:1;
  34         u8              reset_reason:4;
  35 };
  36
  37 #define MPTCP_RM_IDS_MAX        8
  38
  39 struct mptcp_rm_list {
  40         u8 ids[MPTCP_RM_IDS_MAX];
  41         u8 nr;
  42 };
  43
  44 struct mptcp_addr_info {
  45         u8                      id;
  46         sa_family_t             family;
  47         __be16                  port;
  48         union {
  49                 struct in_addr  addr;
  50 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  51                 struct in6_addr addr6;
  52 #endif
  53         };
  54 };
  55
  56 struct mptcp_out_options {
  57 #if IS_ENABLED(CONFIG_MPTCP)
  58         u16 suboptions;
  59         u64 sndr_key;
  60         u64 rcvr_key;
  61         u64 ahmac;
  62         struct mptcp_addr_info addr;
  63         struct mptcp_rm_list rm_list;
  64         u8 join_id;
  65         u8 backup;
  66         u8 reset_reason:4;
  67         u8 reset_transient:1;
  68         u32 nonce;
  69         u64 thmac;
  70         u32 token;
  71         u8 hmac[20];
  72         struct mptcp_ext ext_copy;
  73 #endif
  74 };
  75
  76 #ifdef CONFIG_MPTCP
  77 extern struct request_sock_ops mptcp_subflow_request_sock_ops;
  78
  79 void mptcp_init(void);
  80
  81 static inline bool sk_is_mptcp(const struct sock *sk)
  82 {
  83         return tcp_sk(sk)->is_mptcp;
  84 }
  85
  86 static inline bool rsk_is_mptcp(const struct request_sock *req)
  87 {
  88         return tcp_rsk(req)->is_mptcp;
  89 }
  90
  91 static inline bool rsk_drop_req(const struct request_sock *req)
  92 {
  93         return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
  94 }
  95
  96 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
  97 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
  98                        unsigned int *size, struct mptcp_out_options *opts);
  99 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
 100                           struct mptcp_out_options *opts);
 101 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 102                                unsigned int *size, unsigned int remaining,
 103                                struct mptcp_out_options *opts);
 104 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
 105
 106 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 107                          struct mptcp_out_options *opts);
 108
 109 /* move the skb extension owership, with the assumption that 'to' is
 110  * newly allocated
 111  */
 112 static inline void mptcp_skb_ext_move(struct sk_buff *to,
 113                                       struct sk_buff *from)
 114 {
 115         if (!skb_ext_exist(from, SKB_EXT_MPTCP))
 116                 return;
 117
 118         if (WARN_ON_ONCE(to->active_extensions))
 119                 skb_ext_put(to);
 120
 121         to->active_extensions = from->active_extensions;
 122         to->extensions = from->extensions;
 123         from->active_extensions = 0;
 124 }
 125
 126 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
 127                                       struct sk_buff *from)
 128 {
 129         struct mptcp_ext *from_ext;
 130
 131         from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
 132         if (!from_ext)
 133                 return;
 134
 135         from_ext->frozen = 1;
 136         skb_ext_copy(to, from);
 137 }
 138
 139 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
 140                                      const struct mptcp_ext *from_ext)
 141 {
 142         /* MPTCP always clears the ext when adding it to the skb, so
 143          * holes do not bother us here
 144          */
 145         return !from_ext ||
 146                (to_ext && from_ext &&
 147                 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
 148 }
 149
 150 /* check if skbs can be collapsed.
 151  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
 152  * mapping, or if the extension of @to is the same as @from.
 153  * Collapsing is not possible if @to lacks an extension, but @from carries one.
 154  */
 155 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 156                                           const struct sk_buff *from)
 157 {
 158         return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
 159                                  skb_ext_find(from, SKB_EXT_MPTCP));
 160 }
 161
 162 void mptcp_seq_show(struct seq_file *seq);
 163 int mptcp_subflow_init_cookie_req(struct request_sock *req,
 164                                   const struct sock *sk_listener,
 165                                   struct sk_buff *skb);
 166
 167 __be32 mptcp_get_reset_option(const struct sk_buff *skb);
 168
 169 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
 170 {
 171         if (skb_ext_exist(skb, SKB_EXT_MPTCP))
 172                 return mptcp_get_reset_option(skb);
 173
 174         return htonl(0u);
 175 }
 176 #else
 177
 178 static inline void mptcp_init(void)
 179 {
 180 }
 181
 182 static inline bool sk_is_mptcp(const struct sock *sk)
 183 {
 184         return false;
 185 }
 186
 187 static inline bool rsk_is_mptcp(const struct request_sock *req)
 188 {
 189         return false;
 190 }
 191
 192 static inline bool rsk_drop_req(const struct request_sock *req)
 193 {
 194         return false;
 195 }
 196
 197 static inline void mptcp_parse_option(const struct sk_buff *skb,
 198                                       const unsigned char *ptr, int opsize,
 199                                       struct tcp_options_received *opt_rx)
 200 {
 201 }
 202
 203 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 204                                      unsigned int *size,
 205                                      struct mptcp_out_options *opts)
 206 {
 207         return false;
 208 }
 209
 210 static inline bool mptcp_synack_options(const struct request_sock *req,
 211                                         unsigned int *size,
 212                                         struct mptcp_out_options *opts)
 213 {
 214         return false;
 215 }
 216
 217 static inline bool mptcp_established_options(struct sock *sk,
 218                                              struct sk_buff *skb,
 219                                              unsigned int *size,
 220                                              unsigned int remaining,
 221                                              struct mptcp_out_options *opts)
 222 {
 223         return false;
 224 }
 225
 226 static inline void mptcp_incoming_options(struct sock *sk,
 227                                           struct sk_buff *skb)
 228 {
 229 }
 230
 231 static inline void mptcp_skb_ext_move(struct sk_buff *to,
 232                                       const struct sk_buff *from)
 233 {
 234 }
 235
 236 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
 237                                       struct sk_buff *from)
 238 {
 239 }
 240
 241 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
 242                                           const struct sk_buff *from)
 243 {
 244         return true;
 245 }
 246
 247 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
 248 static inline void mptcp_seq_show(struct seq_file *seq) { }
 249
 250 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
 251                                                 const struct sock *sk_listener,
 252                                                 struct sk_buff *skb)
 253 {
 254         return 0; /* TCP fallback */
 255 }
 256
 257 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
 258 #endif /* CONFIG_MPTCP */
 259
 260 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 261 int mptcpv6_init(void);
 262 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
 263 #elif IS_ENABLED(CONFIG_IPV6)
 264 static inline int mptcpv6_init(void) { return 0; }
 265 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
 266 #endif
 267
 268 #endif /* __NET_MPTCP_H */