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#ifdef CONFIG_MPTCP
100void mptcp_init(void);
101
102static inline bool sk_is_mptcp(const struct sock *sk)
103{
104	return tcp_sk(sk)->is_mptcp;
105}
106
107static inline bool rsk_is_mptcp(const struct request_sock *req)
108{
109	return tcp_rsk(req)->is_mptcp;
110}
111
112static inline bool rsk_drop_req(const struct request_sock *req)
113{
114	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
115}
116
117void mptcp_space(const struct sock *ssk, int *space, int *full_space);
118bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
119		       unsigned int *size, struct mptcp_out_options *opts);
120bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
121			  struct mptcp_out_options *opts);
122bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
123			       unsigned int *size, unsigned int remaining,
124			       struct mptcp_out_options *opts);
125bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
126
127void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
128			 struct mptcp_out_options *opts);
129
130void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
131
132/* move the skb extension owership, with the assumption that 'to' is
133 * newly allocated
134 */
135static inline void mptcp_skb_ext_move(struct sk_buff *to,
136				      struct sk_buff *from)
137{
138	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
139		return;
140
141	if (WARN_ON_ONCE(to->active_extensions))
142		skb_ext_put(to);
143
144	to->active_extensions = from->active_extensions;
145	to->extensions = from->extensions;
146	from->active_extensions = 0;
147}
148
149static inline void mptcp_skb_ext_copy(struct sk_buff *to,
150				      struct sk_buff *from)
151{
152	struct mptcp_ext *from_ext;
153
154	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
155	if (!from_ext)
156		return;
157
158	from_ext->frozen = 1;
159	skb_ext_copy(to, from);
160}
161
162static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
163				     const struct mptcp_ext *from_ext)
164{
165	/* MPTCP always clears the ext when adding it to the skb, so
166	 * holes do not bother us here
167	 */
168	return !from_ext ||
169	       (to_ext && from_ext &&
170	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
171}
172
173/* check if skbs can be collapsed.
174 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
175 * mapping, or if the extension of @to is the same as @from.
176 * Collapsing is not possible if @to lacks an extension, but @from carries one.
177 */
178static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
179					  const struct sk_buff *from)
180{
181	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
182				 skb_ext_find(from, SKB_EXT_MPTCP));
183}
184
185void mptcp_seq_show(struct seq_file *seq);
186int mptcp_subflow_init_cookie_req(struct request_sock *req,
187				  const struct sock *sk_listener,
188				  struct sk_buff *skb);
189struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
190					       struct sock *sk_listener,
191					       bool attach_listener);
192
193__be32 mptcp_get_reset_option(const struct sk_buff *skb);
194
195static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
196{
197	if (skb_ext_exist(skb, SKB_EXT_MPTCP))
198		return mptcp_get_reset_option(skb);
199
200	return htonl(0u);
201}
202#else
203
204static inline void mptcp_init(void)
205{
206}
207
208static inline bool sk_is_mptcp(const struct sock *sk)
209{
210	return false;
211}
212
213static inline bool rsk_is_mptcp(const struct request_sock *req)
214{
215	return false;
216}
217
218static inline bool rsk_drop_req(const struct request_sock *req)
219{
220	return false;
221}
222
223static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
224				     unsigned int *size,
225				     struct mptcp_out_options *opts)
226{
227	return false;
228}
229
230static inline bool mptcp_synack_options(const struct request_sock *req,
231					unsigned int *size,
232					struct mptcp_out_options *opts)
233{
234	return false;
235}
236
237static inline bool mptcp_established_options(struct sock *sk,
238					     struct sk_buff *skb,
239					     unsigned int *size,
240					     unsigned int remaining,
241					     struct mptcp_out_options *opts)
242{
243	return false;
244}
245
246static inline bool mptcp_incoming_options(struct sock *sk,
247					  struct sk_buff *skb)
248{
249	return true;
250}
251
252static inline void mptcp_skb_ext_move(struct sk_buff *to,
253				      const struct sk_buff *from)
254{
255}
256
257static inline void mptcp_skb_ext_copy(struct sk_buff *to,
258				      struct sk_buff *from)
259{
260}
261
262static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
263					  const struct sk_buff *from)
264{
265	return true;
266}
267
268static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
269static inline void mptcp_seq_show(struct seq_file *seq) { }
270
271static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
272						const struct sock *sk_listener,
273						struct sk_buff *skb)
274{
275	return 0; /* TCP fallback */
276}
277
278static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
279							     struct sock *sk_listener,
280							     bool attach_listener)
281{
282	return NULL;
283}
284
285static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
286#endif /* CONFIG_MPTCP */
287
288#if IS_ENABLED(CONFIG_MPTCP_IPV6)
289int mptcpv6_init(void);
290void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
291#elif IS_ENABLED(CONFIG_IPV6)
292static inline int mptcpv6_init(void) { return 0; }
293static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
294#endif
295
296#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
297struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
298#else
299static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
300#endif
301
302#if !IS_ENABLED(CONFIG_MPTCP)
303struct mptcp_sock { };
304#endif
305
306#endif /* __NET_MPTCP_H */