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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 
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 void mptcp_init(void);
62 
sk_is_mptcp(const struct sock * sk)63 static inline bool sk_is_mptcp(const struct sock *sk)
64 {
65 	return tcp_sk(sk)->is_mptcp;
66 }
67 
rsk_is_mptcp(const struct request_sock * req)68 static inline bool rsk_is_mptcp(const struct request_sock *req)
69 {
70 	return tcp_rsk(req)->is_mptcp;
71 }
72 
rsk_drop_req(const struct request_sock * req)73 static inline bool rsk_drop_req(const struct request_sock *req)
74 {
75 	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
76 }
77 
78 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
79 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
80 		       unsigned int *size, struct mptcp_out_options *opts);
81 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
82 			  struct mptcp_out_options *opts);
83 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
84 			       unsigned int *size, unsigned int remaining,
85 			       struct mptcp_out_options *opts);
86 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
87 
88 void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts);
89 
90 /* move the skb extension owership, with the assumption that 'to' is
91  * newly allocated
92  */
mptcp_skb_ext_move(struct sk_buff * to,struct sk_buff * from)93 static inline void mptcp_skb_ext_move(struct sk_buff *to,
94 				      struct sk_buff *from)
95 {
96 	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
97 		return;
98 
99 	if (WARN_ON_ONCE(to->active_extensions))
100 		skb_ext_put(to);
101 
102 	to->active_extensions = from->active_extensions;
103 	to->extensions = from->extensions;
104 	from->active_extensions = 0;
105 }
106 
mptcp_ext_matches(const struct mptcp_ext * to_ext,const struct mptcp_ext * from_ext)107 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
108 				     const struct mptcp_ext *from_ext)
109 {
110 	/* MPTCP always clears the ext when adding it to the skb, so
111 	 * holes do not bother us here
112 	 */
113 	return !from_ext ||
114 	       (to_ext && from_ext &&
115 	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
116 }
117 
118 /* check if skbs can be collapsed.
119  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
120  * mapping, or if the extension of @to is the same as @from.
121  * Collapsing is not possible if @to lacks an extension, but @from carries one.
122  */
mptcp_skb_can_collapse(const struct sk_buff * to,const struct sk_buff * from)123 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
124 					  const struct sk_buff *from)
125 {
126 	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
127 				 skb_ext_find(from, SKB_EXT_MPTCP));
128 }
129 
130 void mptcp_seq_show(struct seq_file *seq);
131 int mptcp_subflow_init_cookie_req(struct request_sock *req,
132 				  const struct sock *sk_listener,
133 				  struct sk_buff *skb);
134 struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
135 					       struct sock *sk_listener,
136 					       bool attach_listener);
137 #else
138 
mptcp_init(void)139 static inline void mptcp_init(void)
140 {
141 }
142 
sk_is_mptcp(const struct sock * sk)143 static inline bool sk_is_mptcp(const struct sock *sk)
144 {
145 	return false;
146 }
147 
rsk_is_mptcp(const struct request_sock * req)148 static inline bool rsk_is_mptcp(const struct request_sock *req)
149 {
150 	return false;
151 }
152 
rsk_drop_req(const struct request_sock * req)153 static inline bool rsk_drop_req(const struct request_sock *req)
154 {
155 	return false;
156 }
157 
mptcp_parse_option(const struct sk_buff * skb,const unsigned char * ptr,int opsize,struct tcp_options_received * opt_rx)158 static inline void mptcp_parse_option(const struct sk_buff *skb,
159 				      const unsigned char *ptr, int opsize,
160 				      struct tcp_options_received *opt_rx)
161 {
162 }
163 
mptcp_syn_options(struct sock * sk,const struct sk_buff * skb,unsigned int * size,struct mptcp_out_options * opts)164 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
165 				     unsigned int *size,
166 				     struct mptcp_out_options *opts)
167 {
168 	return false;
169 }
170 
mptcp_synack_options(const struct request_sock * req,unsigned int * size,struct mptcp_out_options * opts)171 static 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 
mptcp_established_options(struct sock * sk,struct sk_buff * skb,unsigned int * size,unsigned int remaining,struct mptcp_out_options * opts)178 static 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 
mptcp_incoming_options(struct sock * sk,struct sk_buff * skb)187 static inline void mptcp_incoming_options(struct sock *sk,
188 					  struct sk_buff *skb)
189 {
190 }
191 
mptcp_skb_ext_move(struct sk_buff * to,const struct sk_buff * from)192 static inline void mptcp_skb_ext_move(struct sk_buff *to,
193 				      const struct sk_buff *from)
194 {
195 }
196 
mptcp_skb_can_collapse(const struct sk_buff * to,const struct sk_buff * from)197 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
198 					  const struct sk_buff *from)
199 {
200 	return true;
201 }
202 
mptcp_space(const struct sock * ssk,int * s,int * fs)203 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
mptcp_seq_show(struct seq_file * seq)204 static inline void mptcp_seq_show(struct seq_file *seq) { }
205 
mptcp_subflow_init_cookie_req(struct request_sock * req,const struct sock * sk_listener,struct sk_buff * skb)206 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
207 						const struct sock *sk_listener,
208 						struct sk_buff *skb)
209 {
210 	return 0; /* TCP fallback */
211 }
212 
mptcp_subflow_reqsk_alloc(const struct request_sock_ops * ops,struct sock * sk_listener,bool attach_listener)213 static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
214 							     struct sock *sk_listener,
215 							     bool attach_listener)
216 {
217 	return NULL;
218 }
219 #endif /* CONFIG_MPTCP */
220 
221 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
222 int mptcpv6_init(void);
223 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
224 #elif IS_ENABLED(CONFIG_IPV6)
mptcpv6_init(void)225 static inline int mptcpv6_init(void) { return 0; }
mptcpv6_handle_mapped(struct sock * sk,bool mapped)226 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
227 #endif
228 
229 #endif /* __NET_MPTCP_H */
230