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/types.h>
  13
  14 /* MPTCP sk_buff extension data */
  15 struct mptcp_ext {
  16         u64             data_ack;
  17         u64             data_seq;
  18         u32             subflow_seq;
  19         u16             data_len;
  20         u8              use_map:1,
  21                         dsn64:1,
  22                         data_fin:1,
  23                         use_ack:1,
  24                         ack64:1,
  25                         __unused:3;
  26         /* one byte hole */
  27 };
  28
  29 #ifdef CONFIG_MPTCP
  30
  31 void mptcp_init(void);
  32
  33 /* move the skb extension owership, with the assumption that 'to' is
  34  * newly allocated
  35  */
  36 static inline void mptcp_skb_ext_move(struct sk_buff *to,
  37                                       struct sk_buff *from)
  38 {
  39         if (!skb_ext_exist(from, SKB_EXT_MPTCP))
  40                 return;
  41
  42         if (WARN_ON_ONCE(to->active_extensions))
  43                 skb_ext_put(to);
  44
  45         to->active_extensions = from->active_extensions;
  46         to->extensions = from->extensions;
  47         from->active_extensions = 0;
  48 }
  49
  50 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
  51                                      const struct mptcp_ext *from_ext)
  52 {
  53         /* MPTCP always clears the ext when adding it to the skb, so
  54          * holes do not bother us here
  55          */
  56         return !from_ext ||
  57                (to_ext && from_ext &&
  58                 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
  59 }
  60
  61 /* check if skbs can be collapsed.
  62  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
  63  * mapping, or if the extension of @to is the same as @from.
  64  * Collapsing is not possible if @to lacks an extension, but @from carries one.
  65  */
  66 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
  67                                           const struct sk_buff *from)
  68 {
  69         return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
  70                                  skb_ext_find(from, SKB_EXT_MPTCP));
  71 }
  72
  73 #else
  74
  75 static inline void mptcp_init(void)
  76 {
  77 }
  78
  79 static inline void mptcp_skb_ext_move(struct sk_buff *to,
  80                                       const struct sk_buff *from)
  81 {
  82 }
  83
  84 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
  85                                           const struct sk_buff *from)
  86 {
  87         return true;
  88 }
  89
  90 #endif /* CONFIG_MPTCP */
  91
  92 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
  93 int mptcpv6_init(void);
  94 #elif IS_ENABLED(CONFIG_IPV6)
  95 static inline int mptcpv6_init(void)
  96 {
  97         return 0;
  98 }
  99 #endif
 100
 101 #endif /* __NET_MPTCP_H */