xref: /openbmc/linux/include/net/mptcp.h (revision c35a824c)
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 			__unused:1;
34 	/* one byte hole */
35 };
36 
37 struct mptcp_out_options {
38 #if IS_ENABLED(CONFIG_MPTCP)
39 	u16 suboptions;
40 	u64 sndr_key;
41 	u64 rcvr_key;
42 	union {
43 		struct in_addr addr;
44 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
45 		struct in6_addr addr6;
46 #endif
47 	};
48 	u8 addr_id;
49 	u16 port;
50 	u64 ahmac;
51 	u8 rm_id;
52 	u8 join_id;
53 	u8 backup;
54 	u32 nonce;
55 	u64 thmac;
56 	u32 token;
57 	u8 hmac[20];
58 	struct mptcp_ext ext_copy;
59 #endif
60 };
61 
62 #ifdef CONFIG_MPTCP
63 extern struct request_sock_ops mptcp_subflow_request_sock_ops;
64 
65 void mptcp_init(void);
66 
67 static inline bool sk_is_mptcp(const struct sock *sk)
68 {
69 	return tcp_sk(sk)->is_mptcp;
70 }
71 
72 static inline bool rsk_is_mptcp(const struct request_sock *req)
73 {
74 	return tcp_rsk(req)->is_mptcp;
75 }
76 
77 static inline bool rsk_drop_req(const struct request_sock *req)
78 {
79 	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
80 }
81 
82 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
83 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
84 		       unsigned int *size, struct mptcp_out_options *opts);
85 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
86 			  struct mptcp_out_options *opts);
87 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
88 			       unsigned int *size, unsigned int remaining,
89 			       struct mptcp_out_options *opts);
90 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
91 
92 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
93 			 struct mptcp_out_options *opts);
94 
95 /* move the skb extension owership, with the assumption that 'to' is
96  * newly allocated
97  */
98 static inline void mptcp_skb_ext_move(struct sk_buff *to,
99 				      struct sk_buff *from)
100 {
101 	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
102 		return;
103 
104 	if (WARN_ON_ONCE(to->active_extensions))
105 		skb_ext_put(to);
106 
107 	to->active_extensions = from->active_extensions;
108 	to->extensions = from->extensions;
109 	from->active_extensions = 0;
110 }
111 
112 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
113 				      struct sk_buff *from)
114 {
115 	struct mptcp_ext *from_ext;
116 
117 	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
118 	if (!from_ext)
119 		return;
120 
121 	from_ext->frozen = 1;
122 	skb_ext_copy(to, from);
123 }
124 
125 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
126 				     const struct mptcp_ext *from_ext)
127 {
128 	/* MPTCP always clears the ext when adding it to the skb, so
129 	 * holes do not bother us here
130 	 */
131 	return !from_ext ||
132 	       (to_ext && from_ext &&
133 	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
134 }
135 
136 /* check if skbs can be collapsed.
137  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
138  * mapping, or if the extension of @to is the same as @from.
139  * Collapsing is not possible if @to lacks an extension, but @from carries one.
140  */
141 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
142 					  const struct sk_buff *from)
143 {
144 	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
145 				 skb_ext_find(from, SKB_EXT_MPTCP));
146 }
147 
148 void mptcp_seq_show(struct seq_file *seq);
149 int mptcp_subflow_init_cookie_req(struct request_sock *req,
150 				  const struct sock *sk_listener,
151 				  struct sk_buff *skb);
152 #else
153 
154 static inline void mptcp_init(void)
155 {
156 }
157 
158 static inline bool sk_is_mptcp(const struct sock *sk)
159 {
160 	return false;
161 }
162 
163 static inline bool rsk_is_mptcp(const struct request_sock *req)
164 {
165 	return false;
166 }
167 
168 static inline bool rsk_drop_req(const struct request_sock *req)
169 {
170 	return false;
171 }
172 
173 static inline void mptcp_parse_option(const struct sk_buff *skb,
174 				      const unsigned char *ptr, int opsize,
175 				      struct tcp_options_received *opt_rx)
176 {
177 }
178 
179 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
180 				     unsigned int *size,
181 				     struct mptcp_out_options *opts)
182 {
183 	return false;
184 }
185 
186 static inline bool mptcp_synack_options(const struct request_sock *req,
187 					unsigned int *size,
188 					struct mptcp_out_options *opts)
189 {
190 	return false;
191 }
192 
193 static inline bool mptcp_established_options(struct sock *sk,
194 					     struct sk_buff *skb,
195 					     unsigned int *size,
196 					     unsigned int remaining,
197 					     struct mptcp_out_options *opts)
198 {
199 	return false;
200 }
201 
202 static inline void mptcp_incoming_options(struct sock *sk,
203 					  struct sk_buff *skb)
204 {
205 }
206 
207 static inline void mptcp_skb_ext_move(struct sk_buff *to,
208 				      const struct sk_buff *from)
209 {
210 }
211 
212 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
213 				      struct sk_buff *from)
214 {
215 }
216 
217 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
218 					  const struct sk_buff *from)
219 {
220 	return true;
221 }
222 
223 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
224 static inline void mptcp_seq_show(struct seq_file *seq) { }
225 
226 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
227 						const struct sock *sk_listener,
228 						struct sk_buff *skb)
229 {
230 	return 0; /* TCP fallback */
231 }
232 #endif /* CONFIG_MPTCP */
233 
234 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
235 int mptcpv6_init(void);
236 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
237 #elif IS_ENABLED(CONFIG_IPV6)
238 static inline int mptcpv6_init(void) { return 0; }
239 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
240 #endif
241 
242 #endif /* __NET_MPTCP_H */
243