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 mptcp_info;
16struct mptcp_sock;
17struct seq_file;
18
19/* MPTCP sk_buff extension data */
20struct 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
45struct mptcp_rm_list {
46	u8 ids[MPTCP_RM_IDS_MAX];
47	u8 nr;
48};
49
50struct 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
62struct 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_SCHED_MAX		128
101#define MPTCP_SCHED_BUF_MAX	(MPTCP_SCHED_NAME_MAX * MPTCP_SCHED_MAX)
102
103#define MPTCP_SUBFLOWS_MAX	8
104
105struct mptcp_sched_data {
106	bool	reinject;
107	u8	subflows;
108	struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
109};
110
111struct mptcp_sched_ops {
112	int (*get_subflow)(struct mptcp_sock *msk,
113			   struct mptcp_sched_data *data);
114
115	char			name[MPTCP_SCHED_NAME_MAX];
116	struct module		*owner;
117	struct list_head	list;
118
119	void (*init)(struct mptcp_sock *msk);
120	void (*release)(struct mptcp_sock *msk);
121} ____cacheline_aligned_in_smp;
122
123#ifdef CONFIG_MPTCP
124void mptcp_init(void);
125
126static inline bool sk_is_mptcp(const struct sock *sk)
127{
128	return tcp_sk(sk)->is_mptcp;
129}
130
131static inline bool rsk_is_mptcp(const struct request_sock *req)
132{
133	return tcp_rsk(req)->is_mptcp;
134}
135
136static inline bool rsk_drop_req(const struct request_sock *req)
137{
138	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
139}
140
141void mptcp_space(const struct sock *ssk, int *space, int *full_space);
142bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
143		       unsigned int *size, struct mptcp_out_options *opts);
144bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
145			  struct mptcp_out_options *opts);
146bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
147			       unsigned int *size, unsigned int remaining,
148			       struct mptcp_out_options *opts);
149bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
150
151void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
152			 struct mptcp_out_options *opts);
153
154void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
155
156/* move the skb extension owership, with the assumption that 'to' is
157 * newly allocated
158 */
159static inline void mptcp_skb_ext_move(struct sk_buff *to,
160				      struct sk_buff *from)
161{
162	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
163		return;
164
165	if (WARN_ON_ONCE(to->active_extensions))
166		skb_ext_put(to);
167
168	to->active_extensions = from->active_extensions;
169	to->extensions = from->extensions;
170	from->active_extensions = 0;
171}
172
173static inline void mptcp_skb_ext_copy(struct sk_buff *to,
174				      struct sk_buff *from)
175{
176	struct mptcp_ext *from_ext;
177
178	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
179	if (!from_ext)
180		return;
181
182	from_ext->frozen = 1;
183	skb_ext_copy(to, from);
184}
185
186static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
187				     const struct mptcp_ext *from_ext)
188{
189	/* MPTCP always clears the ext when adding it to the skb, so
190	 * holes do not bother us here
191	 */
192	return !from_ext ||
193	       (to_ext && from_ext &&
194	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
195}
196
197/* check if skbs can be collapsed.
198 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
199 * mapping, or if the extension of @to is the same as @from.
200 * Collapsing is not possible if @to lacks an extension, but @from carries one.
201 */
202static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
203					  const struct sk_buff *from)
204{
205	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
206				 skb_ext_find(from, SKB_EXT_MPTCP));
207}
208
209void mptcp_seq_show(struct seq_file *seq);
210int mptcp_subflow_init_cookie_req(struct request_sock *req,
211				  const struct sock *sk_listener,
212				  struct sk_buff *skb);
213struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
214					       struct sock *sk_listener,
215					       bool attach_listener);
216
217__be32 mptcp_get_reset_option(const struct sk_buff *skb);
218
219static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
220{
221	if (skb_ext_exist(skb, SKB_EXT_MPTCP))
222		return mptcp_get_reset_option(skb);
223
224	return htonl(0u);
225}
226#else
227
228static inline void mptcp_init(void)
229{
230}
231
232static inline bool sk_is_mptcp(const struct sock *sk)
233{
234	return false;
235}
236
237static inline bool rsk_is_mptcp(const struct request_sock *req)
238{
239	return false;
240}
241
242static inline bool rsk_drop_req(const struct request_sock *req)
243{
244	return false;
245}
246
247static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
248				     unsigned int *size,
249				     struct mptcp_out_options *opts)
250{
251	return false;
252}
253
254static inline bool mptcp_synack_options(const struct request_sock *req,
255					unsigned int *size,
256					struct mptcp_out_options *opts)
257{
258	return false;
259}
260
261static inline bool mptcp_established_options(struct sock *sk,
262					     struct sk_buff *skb,
263					     unsigned int *size,
264					     unsigned int remaining,
265					     struct mptcp_out_options *opts)
266{
267	return false;
268}
269
270static inline bool mptcp_incoming_options(struct sock *sk,
271					  struct sk_buff *skb)
272{
273	return true;
274}
275
276static inline void mptcp_skb_ext_move(struct sk_buff *to,
277				      const struct sk_buff *from)
278{
279}
280
281static inline void mptcp_skb_ext_copy(struct sk_buff *to,
282				      struct sk_buff *from)
283{
284}
285
286static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
287					  const struct sk_buff *from)
288{
289	return true;
290}
291
292static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
293static inline void mptcp_seq_show(struct seq_file *seq) { }
294
295static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
296						const struct sock *sk_listener,
297						struct sk_buff *skb)
298{
299	return 0; /* TCP fallback */
300}
301
302static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
303							     struct sock *sk_listener,
304							     bool attach_listener)
305{
306	return NULL;
307}
308
309static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
310#endif /* CONFIG_MPTCP */
311
312#if IS_ENABLED(CONFIG_MPTCP_IPV6)
313int mptcpv6_init(void);
314void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
315#elif IS_ENABLED(CONFIG_IPV6)
316static inline int mptcpv6_init(void) { return 0; }
317static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
318#endif
319
320#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
321struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
322#else
323static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
324#endif
325
326#if !IS_ENABLED(CONFIG_MPTCP)
327struct mptcp_sock { };
328#endif
329
330#endif /* __NET_MPTCP_H */
331