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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
15struct seq_file;
16
17/* MPTCP sk_buff extension data */
18struct 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
36struct 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
62void mptcp_init(void);
63
64static inline bool sk_is_mptcp(const struct sock *sk)
65{
66 return tcp_sk(sk)->is_mptcp;
67}
68
69static inline bool rsk_is_mptcp(const struct request_sock *req)
70{
71 return tcp_rsk(req)->is_mptcp;
72}
73
74static inline bool rsk_drop_req(const struct request_sock *req)
75{
76 return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
77}
78
79void mptcp_space(const struct sock *ssk, int *space, int *full_space);
80bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
81 unsigned int *size, struct mptcp_out_options *opts);
82bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
83 struct mptcp_out_options *opts);
84bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
85 unsigned int *size, unsigned int remaining,
86 struct mptcp_out_options *opts);
87void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
88 struct tcp_options_received *opt_rx);
89
90void 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 */
95static 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
109static 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 */
125static 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
132void mptcp_seq_show(struct seq_file *seq);
133#else
134
135static inline void mptcp_init(void)
136{
137}
138
139static inline bool sk_is_mptcp(const struct sock *sk)
140{
141 return false;
142}
143
144static inline bool rsk_is_mptcp(const struct request_sock *req)
145{
146 return false;
147}
148
149static inline bool rsk_drop_req(const struct request_sock *req)
150{
151 return false;
152}
153
154static inline void mptcp_parse_option(const struct sk_buff *skb,
155 const unsigned char *ptr, int opsize,
156 struct tcp_options_received *opt_rx)
157{
158}
159
160static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
161 unsigned int *size,
162 struct mptcp_out_options *opts)
163{
164 return false;
165}
166
167static inline void mptcp_rcv_synsent(struct sock *sk)
168{
169}
170
171static inline bool mptcp_synack_options(const struct request_sock *req,
172 unsigned int *size,
173 struct mptcp_out_options *opts)
174{
175 return false;
176}
177
178static inline bool mptcp_established_options(struct sock *sk,
179 struct sk_buff *skb,
180 unsigned int *size,
181 unsigned int remaining,
182 struct mptcp_out_options *opts)
183{
184 return false;
185}
186
187static inline void mptcp_incoming_options(struct sock *sk,
188 struct sk_buff *skb,
189 struct tcp_options_received *opt_rx)
190{
191}
192
193static inline void mptcp_skb_ext_move(struct sk_buff *to,
194 const struct sk_buff *from)
195{
196}
197
198static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
199 const struct sk_buff *from)
200{
201 return true;
202}
203
204static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
205static inline void mptcp_seq_show(struct seq_file *seq) { }
206#endif /* CONFIG_MPTCP */
207
208#if IS_ENABLED(CONFIG_MPTCP_IPV6)
209int mptcpv6_init(void);
210void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
211#elif IS_ENABLED(CONFIG_IPV6)
212static inline int mptcpv6_init(void) { return 0; }
213static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
214#endif
215
216#endif /* __NET_MPTCP_H */