xref: /openbmc/linux/include/net/mptcp.h (revision 4bb1eb3c)
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 extern struct request_sock_ops mptcp_subflow_request_sock_ops;
62 
63 void mptcp_init(void);
64 
65 static inline bool sk_is_mptcp(const struct sock *sk)
66 {
67 	return tcp_sk(sk)->is_mptcp;
68 }
69 
70 static inline bool rsk_is_mptcp(const struct request_sock *req)
71 {
72 	return tcp_rsk(req)->is_mptcp;
73 }
74 
75 static inline bool rsk_drop_req(const struct request_sock *req)
76 {
77 	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
78 }
79 
80 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
81 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
82 		       unsigned int *size, struct mptcp_out_options *opts);
83 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
84 			  struct mptcp_out_options *opts);
85 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
86 			       unsigned int *size, unsigned int remaining,
87 			       struct mptcp_out_options *opts);
88 void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
89 			    struct tcp_options_received *opt_rx);
90 
91 void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts);
92 
93 /* move the skb extension owership, with the assumption that 'to' is
94  * newly allocated
95  */
96 static inline void mptcp_skb_ext_move(struct sk_buff *to,
97 				      struct sk_buff *from)
98 {
99 	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
100 		return;
101 
102 	if (WARN_ON_ONCE(to->active_extensions))
103 		skb_ext_put(to);
104 
105 	to->active_extensions = from->active_extensions;
106 	to->extensions = from->extensions;
107 	from->active_extensions = 0;
108 }
109 
110 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
111 				     const struct mptcp_ext *from_ext)
112 {
113 	/* MPTCP always clears the ext when adding it to the skb, so
114 	 * holes do not bother us here
115 	 */
116 	return !from_ext ||
117 	       (to_ext && from_ext &&
118 	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
119 }
120 
121 /* check if skbs can be collapsed.
122  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
123  * mapping, or if the extension of @to is the same as @from.
124  * Collapsing is not possible if @to lacks an extension, but @from carries one.
125  */
126 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
127 					  const struct sk_buff *from)
128 {
129 	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
130 				 skb_ext_find(from, SKB_EXT_MPTCP));
131 }
132 
133 void mptcp_seq_show(struct seq_file *seq);
134 int mptcp_subflow_init_cookie_req(struct request_sock *req,
135 				  const struct sock *sk_listener,
136 				  struct sk_buff *skb);
137 #else
138 
139 static inline void mptcp_init(void)
140 {
141 }
142 
143 static inline bool sk_is_mptcp(const struct sock *sk)
144 {
145 	return false;
146 }
147 
148 static inline bool rsk_is_mptcp(const struct request_sock *req)
149 {
150 	return false;
151 }
152 
153 static inline bool rsk_drop_req(const struct request_sock *req)
154 {
155 	return false;
156 }
157 
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 
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 
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 
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 
187 static inline void mptcp_incoming_options(struct sock *sk,
188 					  struct sk_buff *skb,
189 					  struct tcp_options_received *opt_rx)
190 {
191 }
192 
193 static inline void mptcp_skb_ext_move(struct sk_buff *to,
194 				      const struct sk_buff *from)
195 {
196 }
197 
198 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
199 					  const struct sk_buff *from)
200 {
201 	return true;
202 }
203 
204 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
205 static inline void mptcp_seq_show(struct seq_file *seq) { }
206 
207 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
208 						const struct sock *sk_listener,
209 						struct sk_buff *skb)
210 {
211 	return 0; /* TCP fallback */
212 }
213 #endif /* CONFIG_MPTCP */
214 
215 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
216 int mptcpv6_init(void);
217 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
218 #elif IS_ENABLED(CONFIG_IPV6)
219 static inline int mptcpv6_init(void) { return 0; }
220 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
221 #endif
222 
223 #endif /* __NET_MPTCP_H */
224