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	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
 36struct 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
 61extern struct request_sock_ops mptcp_subflow_request_sock_ops;
 62
 63void mptcp_init(void);
 64
 65static inline bool sk_is_mptcp(const struct sock *sk)
 66{
 67	return tcp_sk(sk)->is_mptcp;
 68}
 69
 70static inline bool rsk_is_mptcp(const struct request_sock *req)
 71{
 72	return tcp_rsk(req)->is_mptcp;
 73}
 74
 75static 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
 80void mptcp_space(const struct sock *ssk, int *space, int *full_space);
 81bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
 82		       unsigned int *size, struct mptcp_out_options *opts);
 83bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
 84			  struct mptcp_out_options *opts);
 85bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
 86			       unsigned int *size, unsigned int remaining,
 87			       struct mptcp_out_options *opts);
 88void mptcp_incoming_options(struct sock *sk, struct sk_buff *skb,
 89			    struct tcp_options_received *opt_rx);
 90
 91void 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 */
 96static 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
110static 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 */
126static 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
133void mptcp_seq_show(struct seq_file *seq);
134int mptcp_subflow_init_cookie_req(struct request_sock *req,
135				  const struct sock *sk_listener,
136				  struct sk_buff *skb);
137#else
138
139static inline void mptcp_init(void)
140{
141}
142
143static inline bool sk_is_mptcp(const struct sock *sk)
144{
145	return false;
146}
147
148static inline bool rsk_is_mptcp(const struct request_sock *req)
149{
150	return false;
151}
152
153static inline bool rsk_drop_req(const struct request_sock *req)
154{
155	return false;
156}
157
158static 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
164static 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
171static 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
178static 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
187static inline void mptcp_incoming_options(struct sock *sk,
188					  struct sk_buff *skb,
189					  struct tcp_options_received *opt_rx)
190{
191}
192
193static inline void mptcp_skb_ext_move(struct sk_buff *to,
194				      const struct sk_buff *from)
195{
196}
197
198static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
199					  const struct sk_buff *from)
200{
201	return true;
202}
203
204static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
205static inline void mptcp_seq_show(struct seq_file *seq) { }
206
207static 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)
216int mptcpv6_init(void);
217void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
218#elif IS_ENABLED(CONFIG_IPV6)
219static inline int mptcpv6_init(void) { return 0; }
220static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
221#endif
222
223#endif /* __NET_MPTCP_H */