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 /* move the skb extension owership, with the assumption that 'to' is 32 * newly allocated 33 */ 34 static inline void mptcp_skb_ext_move(struct sk_buff *to, 35 struct sk_buff *from) 36 { 37 if (!skb_ext_exist(from, SKB_EXT_MPTCP)) 38 return; 39 40 if (WARN_ON_ONCE(to->active_extensions)) 41 skb_ext_put(to); 42 43 to->active_extensions = from->active_extensions; 44 to->extensions = from->extensions; 45 from->active_extensions = 0; 46 } 47 48 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext, 49 const struct mptcp_ext *from_ext) 50 { 51 /* MPTCP always clears the ext when adding it to the skb, so 52 * holes do not bother us here 53 */ 54 return !from_ext || 55 (to_ext && from_ext && 56 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext))); 57 } 58 59 /* check if skbs can be collapsed. 60 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data 61 * mapping, or if the extension of @to is the same as @from. 62 * Collapsing is not possible if @to lacks an extension, but @from carries one. 63 */ 64 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to, 65 const struct sk_buff *from) 66 { 67 return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP), 68 skb_ext_find(from, SKB_EXT_MPTCP)); 69 } 70 71 #else 72 73 static inline void mptcp_skb_ext_move(struct sk_buff *to, 74 const struct sk_buff *from) 75 { 76 } 77 78 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to, 79 const struct sk_buff *from) 80 { 81 return true; 82 } 83 84 #endif /* CONFIG_MPTCP */ 85 #endif /* __NET_MPTCP_H */ 86