xref: /openbmc/linux/include/net/mptcp.h (revision 740ebe35)
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 mptcp_info;
16 struct mptcp_sock;
17 struct seq_file;
18 
19 /* MPTCP sk_buff extension data */
20 struct mptcp_ext {
21 	union {
22 		u64	data_ack;
23 		u32	data_ack32;
24 	};
25 	u64		data_seq;
26 	u32		subflow_seq;
27 	u16		data_len;
28 	__sum16		csum;
29 	u8		use_map:1,
30 			dsn64:1,
31 			data_fin:1,
32 			use_ack:1,
33 			ack64:1,
34 			mpc_map:1,
35 			frozen:1,
36 			reset_transient:1;
37 	u8		reset_reason:4,
38 			csum_reqd:1,
39 			infinite_map:1;
40 };
41 
42 #define MPTCPOPT_HMAC_LEN	20
43 #define MPTCP_RM_IDS_MAX	8
44 
45 struct mptcp_rm_list {
46 	u8 ids[MPTCP_RM_IDS_MAX];
47 	u8 nr;
48 };
49 
50 struct mptcp_addr_info {
51 	u8			id;
52 	sa_family_t		family;
53 	__be16			port;
54 	union {
55 		struct in_addr	addr;
56 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
57 		struct in6_addr	addr6;
58 #endif
59 	};
60 };
61 
62 struct mptcp_out_options {
63 #if IS_ENABLED(CONFIG_MPTCP)
64 	u16 suboptions;
65 	struct mptcp_rm_list rm_list;
66 	u8 join_id;
67 	u8 backup;
68 	u8 reset_reason:4,
69 	   reset_transient:1,
70 	   csum_reqd:1,
71 	   allow_join_id0:1;
72 	union {
73 		struct {
74 			u64 sndr_key;
75 			u64 rcvr_key;
76 			u64 data_seq;
77 			u32 subflow_seq;
78 			u16 data_len;
79 			__sum16 csum;
80 		};
81 		struct {
82 			struct mptcp_addr_info addr;
83 			u64 ahmac;
84 		};
85 		struct {
86 			struct mptcp_ext ext_copy;
87 			u64 fail_seq;
88 		};
89 		struct {
90 			u32 nonce;
91 			u32 token;
92 			u64 thmac;
93 			u8 hmac[MPTCPOPT_HMAC_LEN];
94 		};
95 	};
96 #endif
97 };
98 
99 #define MPTCP_SCHED_NAME_MAX	16
100 #define MPTCP_SUBFLOWS_MAX	8
101 
102 struct mptcp_sched_data {
103 	bool	reinject;
104 	u8	subflows;
105 	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
106 };
107 
108 struct mptcp_sched_ops {
109 	int (*get_subflow)(struct mptcp_sock *msk,
110 			   struct mptcp_sched_data *data);
111 
112 	char			name[MPTCP_SCHED_NAME_MAX];
113 	struct module		*owner;
114 	struct list_head	list;
115 
116 	void (*init)(struct mptcp_sock *msk);
117 	void (*release)(struct mptcp_sock *msk);
118 } ____cacheline_aligned_in_smp;
119 
120 #ifdef CONFIG_MPTCP
121 void mptcp_init(void);
122 
sk_is_mptcp(const struct sock * sk)123 static inline bool sk_is_mptcp(const struct sock *sk)
124 {
125 	return tcp_sk(sk)->is_mptcp;
126 }
127 
rsk_is_mptcp(const struct request_sock * req)128 static inline bool rsk_is_mptcp(const struct request_sock *req)
129 {
130 	return tcp_rsk(req)->is_mptcp;
131 }
132 
rsk_drop_req(const struct request_sock * req)133 static inline bool rsk_drop_req(const struct request_sock *req)
134 {
135 	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
136 }
137 
138 void mptcp_space(const struct sock *ssk, int *space, int *full_space);
139 bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
140 		       unsigned int *size, struct mptcp_out_options *opts);
141 bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
142 			  struct mptcp_out_options *opts);
143 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
144 			       unsigned int *size, unsigned int remaining,
145 			       struct mptcp_out_options *opts);
146 bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
147 
148 void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
149 			 struct mptcp_out_options *opts);
150 
151 void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
152 
153 /* move the skb extension owership, with the assumption that 'to' is
154  * newly allocated
155  */
mptcp_skb_ext_move(struct sk_buff * to,struct sk_buff * from)156 static inline void mptcp_skb_ext_move(struct sk_buff *to,
157 				      struct sk_buff *from)
158 {
159 	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
160 		return;
161 
162 	if (WARN_ON_ONCE(to->active_extensions))
163 		skb_ext_put(to);
164 
165 	to->active_extensions = from->active_extensions;
166 	to->extensions = from->extensions;
167 	from->active_extensions = 0;
168 }
169 
mptcp_skb_ext_copy(struct sk_buff * to,struct sk_buff * from)170 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
171 				      struct sk_buff *from)
172 {
173 	struct mptcp_ext *from_ext;
174 
175 	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
176 	if (!from_ext)
177 		return;
178 
179 	from_ext->frozen = 1;
180 	skb_ext_copy(to, from);
181 }
182 
mptcp_ext_matches(const struct mptcp_ext * to_ext,const struct mptcp_ext * from_ext)183 static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
184 				     const struct mptcp_ext *from_ext)
185 {
186 	/* MPTCP always clears the ext when adding it to the skb, so
187 	 * holes do not bother us here
188 	 */
189 	return !from_ext ||
190 	       (to_ext && from_ext &&
191 	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
192 }
193 
194 /* check if skbs can be collapsed.
195  * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
196  * mapping, or if the extension of @to is the same as @from.
197  * Collapsing is not possible if @to lacks an extension, but @from carries one.
198  */
mptcp_skb_can_collapse(const struct sk_buff * to,const struct sk_buff * from)199 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
200 					  const struct sk_buff *from)
201 {
202 	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
203 				 skb_ext_find(from, SKB_EXT_MPTCP));
204 }
205 
206 void mptcp_seq_show(struct seq_file *seq);
207 int mptcp_subflow_init_cookie_req(struct request_sock *req,
208 				  const struct sock *sk_listener,
209 				  struct sk_buff *skb);
210 struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
211 					       struct sock *sk_listener,
212 					       bool attach_listener);
213 
214 __be32 mptcp_get_reset_option(const struct sk_buff *skb);
215 
mptcp_reset_option(const struct sk_buff * skb)216 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
217 {
218 	if (skb_ext_exist(skb, SKB_EXT_MPTCP))
219 		return mptcp_get_reset_option(skb);
220 
221 	return htonl(0u);
222 }
223 #else
224 
mptcp_init(void)225 static inline void mptcp_init(void)
226 {
227 }
228 
sk_is_mptcp(const struct sock * sk)229 static inline bool sk_is_mptcp(const struct sock *sk)
230 {
231 	return false;
232 }
233 
rsk_is_mptcp(const struct request_sock * req)234 static inline bool rsk_is_mptcp(const struct request_sock *req)
235 {
236 	return false;
237 }
238 
rsk_drop_req(const struct request_sock * req)239 static inline bool rsk_drop_req(const struct request_sock *req)
240 {
241 	return false;
242 }
243 
mptcp_syn_options(struct sock * sk,const struct sk_buff * skb,unsigned int * size,struct mptcp_out_options * opts)244 static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
245 				     unsigned int *size,
246 				     struct mptcp_out_options *opts)
247 {
248 	return false;
249 }
250 
mptcp_synack_options(const struct request_sock * req,unsigned int * size,struct mptcp_out_options * opts)251 static inline bool mptcp_synack_options(const struct request_sock *req,
252 					unsigned int *size,
253 					struct mptcp_out_options *opts)
254 {
255 	return false;
256 }
257 
mptcp_established_options(struct sock * sk,struct sk_buff * skb,unsigned int * size,unsigned int remaining,struct mptcp_out_options * opts)258 static inline bool mptcp_established_options(struct sock *sk,
259 					     struct sk_buff *skb,
260 					     unsigned int *size,
261 					     unsigned int remaining,
262 					     struct mptcp_out_options *opts)
263 {
264 	return false;
265 }
266 
mptcp_incoming_options(struct sock * sk,struct sk_buff * skb)267 static inline bool mptcp_incoming_options(struct sock *sk,
268 					  struct sk_buff *skb)
269 {
270 	return true;
271 }
272 
mptcp_skb_ext_move(struct sk_buff * to,const struct sk_buff * from)273 static inline void mptcp_skb_ext_move(struct sk_buff *to,
274 				      const struct sk_buff *from)
275 {
276 }
277 
mptcp_skb_ext_copy(struct sk_buff * to,struct sk_buff * from)278 static inline void mptcp_skb_ext_copy(struct sk_buff *to,
279 				      struct sk_buff *from)
280 {
281 }
282 
mptcp_skb_can_collapse(const struct sk_buff * to,const struct sk_buff * from)283 static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
284 					  const struct sk_buff *from)
285 {
286 	return true;
287 }
288 
mptcp_space(const struct sock * ssk,int * s,int * fs)289 static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
mptcp_seq_show(struct seq_file * seq)290 static inline void mptcp_seq_show(struct seq_file *seq) { }
291 
mptcp_subflow_init_cookie_req(struct request_sock * req,const struct sock * sk_listener,struct sk_buff * skb)292 static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
293 						const struct sock *sk_listener,
294 						struct sk_buff *skb)
295 {
296 	return 0; /* TCP fallback */
297 }
298 
mptcp_subflow_reqsk_alloc(const struct request_sock_ops * ops,struct sock * sk_listener,bool attach_listener)299 static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
300 							     struct sock *sk_listener,
301 							     bool attach_listener)
302 {
303 	return NULL;
304 }
305 
mptcp_reset_option(const struct sk_buff * skb)306 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
307 #endif /* CONFIG_MPTCP */
308 
309 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
310 int mptcpv6_init(void);
311 void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
312 #elif IS_ENABLED(CONFIG_IPV6)
mptcpv6_init(void)313 static inline int mptcpv6_init(void) { return 0; }
mptcpv6_handle_mapped(struct sock * sk,bool mapped)314 static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
315 #endif
316 
317 #if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
318 struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
319 #else
bpf_mptcp_sock_from_subflow(struct sock * sk)320 static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
321 #endif
322 
323 #if !IS_ENABLED(CONFIG_MPTCP)
324 struct mptcp_sock { };
325 #endif
326 
327 #endif /* __NET_MPTCP_H */
328