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 seq_file;
 16
 17/* MPTCP sk_buff extension data */
 18struct 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	__sum16		csum;
 27	u8		use_map:1,
 28			dsn64:1,
 29			data_fin:1,
 30			use_ack:1,
 31			ack64:1,
 32			mpc_map:1,
 33			frozen:1,
 34			reset_transient:1;
 35	u8		reset_reason:4,
 36			csum_reqd:1;
 37};
 38
 39#define MPTCP_RM_IDS_MAX	8
 40
 41struct mptcp_rm_list {
 42	u8 ids[MPTCP_RM_IDS_MAX];
 43	u8 nr;
 44};
 45
 46struct mptcp_addr_info {
 47	u8			id;
 48	sa_family_t		family;
 49	__be16			port;
 50	union {
 51		struct in_addr	addr;
 52#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 53		struct in6_addr	addr6;
 54#endif
 55	};
 56};
 57
 58struct mptcp_out_options {
 59#if IS_ENABLED(CONFIG_MPTCP)
 60	u16 suboptions;
 61	u64 sndr_key;
 62	u64 rcvr_key;
 63	u64 ahmac;
 64	struct mptcp_addr_info addr;
 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	u32 nonce;
 73	u64 thmac;
 74	u32 token;
 75	u8 hmac[20];
 76	struct mptcp_ext ext_copy;
 77#endif
 78};
 79
 80#ifdef CONFIG_MPTCP
 81extern struct request_sock_ops mptcp_subflow_request_sock_ops;
 82
 83void mptcp_init(void);
 84
 85static inline bool sk_is_mptcp(const struct sock *sk)
 86{
 87	return tcp_sk(sk)->is_mptcp;
 88}
 89
 90static inline bool rsk_is_mptcp(const struct request_sock *req)
 91{
 92	return tcp_rsk(req)->is_mptcp;
 93}
 94
 95static inline bool rsk_drop_req(const struct request_sock *req)
 96{
 97	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
 98}
 99
100void mptcp_space(const struct sock *ssk, int *space, int *full_space);
101bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
102		       unsigned int *size, struct mptcp_out_options *opts);
103bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
104			  struct mptcp_out_options *opts);
105bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
106			       unsigned int *size, unsigned int remaining,
107			       struct mptcp_out_options *opts);
108bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
109
110void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
111			 struct mptcp_out_options *opts);
112
113/* move the skb extension owership, with the assumption that 'to' is
114 * newly allocated
115 */
116static inline void mptcp_skb_ext_move(struct sk_buff *to,
117				      struct sk_buff *from)
118{
119	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
120		return;
121
122	if (WARN_ON_ONCE(to->active_extensions))
123		skb_ext_put(to);
124
125	to->active_extensions = from->active_extensions;
126	to->extensions = from->extensions;
127	from->active_extensions = 0;
128}
129
130static inline void mptcp_skb_ext_copy(struct sk_buff *to,
131				      struct sk_buff *from)
132{
133	struct mptcp_ext *from_ext;
134
135	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
136	if (!from_ext)
137		return;
138
139	from_ext->frozen = 1;
140	skb_ext_copy(to, from);
141}
142
143static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
144				     const struct mptcp_ext *from_ext)
145{
146	/* MPTCP always clears the ext when adding it to the skb, so
147	 * holes do not bother us here
148	 */
149	return !from_ext ||
150	       (to_ext && from_ext &&
151	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
152}
153
154/* check if skbs can be collapsed.
155 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
156 * mapping, or if the extension of @to is the same as @from.
157 * Collapsing is not possible if @to lacks an extension, but @from carries one.
158 */
159static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
160					  const struct sk_buff *from)
161{
162	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
163				 skb_ext_find(from, SKB_EXT_MPTCP));
164}
165
166void mptcp_seq_show(struct seq_file *seq);
167int mptcp_subflow_init_cookie_req(struct request_sock *req,
168				  const struct sock *sk_listener,
169				  struct sk_buff *skb);
170
171__be32 mptcp_get_reset_option(const struct sk_buff *skb);
172
173static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
174{
175	if (skb_ext_exist(skb, SKB_EXT_MPTCP))
176		return mptcp_get_reset_option(skb);
177
178	return htonl(0u);
179}
180#else
181
182static inline void mptcp_init(void)
183{
184}
185
186static inline bool sk_is_mptcp(const struct sock *sk)
187{
188	return false;
189}
190
191static inline bool rsk_is_mptcp(const struct request_sock *req)
192{
193	return false;
194}
195
196static inline bool rsk_drop_req(const struct request_sock *req)
197{
198	return false;
199}
200
201static inline void mptcp_parse_option(const struct sk_buff *skb,
202				      const unsigned char *ptr, int opsize,
203				      struct tcp_options_received *opt_rx)
204{
205}
206
207static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
208				     unsigned int *size,
209				     struct mptcp_out_options *opts)
210{
211	return false;
212}
213
214static inline bool mptcp_synack_options(const struct request_sock *req,
215					unsigned int *size,
216					struct mptcp_out_options *opts)
217{
218	return false;
219}
220
221static inline bool mptcp_established_options(struct sock *sk,
222					     struct sk_buff *skb,
223					     unsigned int *size,
224					     unsigned int remaining,
225					     struct mptcp_out_options *opts)
226{
227	return false;
228}
229
230static inline bool mptcp_incoming_options(struct sock *sk,
231					  struct sk_buff *skb)
232{
233	return true;
234}
235
236static inline void mptcp_skb_ext_move(struct sk_buff *to,
237				      const struct sk_buff *from)
238{
239}
240
241static inline void mptcp_skb_ext_copy(struct sk_buff *to,
242				      struct sk_buff *from)
243{
244}
245
246static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
247					  const struct sk_buff *from)
248{
249	return true;
250}
251
252static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
253static inline void mptcp_seq_show(struct seq_file *seq) { }
254
255static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
256						const struct sock *sk_listener,
257						struct sk_buff *skb)
258{
259	return 0; /* TCP fallback */
260}
261
262static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
263#endif /* CONFIG_MPTCP */
264
265#if IS_ENABLED(CONFIG_MPTCP_IPV6)
266int mptcpv6_init(void);
267void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
268#elif IS_ENABLED(CONFIG_IPV6)
269static inline int mptcpv6_init(void) { return 0; }
270static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
271#endif
272
273#endif /* __NET_MPTCP_H */