mptcp.h

  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 mptcp_pm_addr_entry;
 18struct seq_file;
 19
 20/* MPTCP sk_buff extension data */
 21struct mptcp_ext {
 22	union {
 23		u64	data_ack;
 24		u32	data_ack32;
 25	};
 26	u64		data_seq;
 27	u32		subflow_seq;
 28	u16		data_len;
 29	__sum16		csum;
 30	u8		use_map:1,
 31			dsn64:1,
 32			data_fin:1,
 33			use_ack:1,
 34			ack64:1,
 35			mpc_map:1,
 36			frozen:1,
 37			reset_transient:1;
 38	u8		reset_reason:4,
 39			csum_reqd:1,
 40			infinite_map:1;
 41};
 42
 43#define MPTCPOPT_HMAC_LEN	20
 44#define MPTCP_RM_IDS_MAX	8
 45
 46struct mptcp_rm_list {
 47	u8 ids[MPTCP_RM_IDS_MAX];
 48	u8 nr;
 49};
 50
 51struct mptcp_addr_info {
 52	u8			id;
 53	sa_family_t		family;
 54	__be16			port;
 55	union {
 56		struct in_addr	addr;
 57#if IS_ENABLED(CONFIG_MPTCP_IPV6)
 58		struct in6_addr	addr6;
 59#endif
 60	};
 61};
 62
 63struct mptcp_out_options {
 64#if IS_ENABLED(CONFIG_MPTCP)
 65	u16 suboptions;
 66	struct mptcp_rm_list rm_list;
 67	u8 join_id;
 68	u8 backup;
 69	u8 reset_reason:4,
 70	   reset_transient:1,
 71	   csum_reqd:1,
 72	   allow_join_id0:1;
 73	union {
 74		struct {
 75			u64 sndr_key;
 76			u64 rcvr_key;
 77			u64 data_seq;
 78			u32 subflow_seq;
 79			u16 data_len;
 80			__sum16 csum;
 81		};
 82		struct {
 83			struct mptcp_addr_info addr;
 84			u64 ahmac;
 85		};
 86		struct {
 87			struct mptcp_ext ext_copy;
 88			u64 fail_seq;
 89		};
 90		struct {
 91			u32 nonce;
 92			u32 token;
 93			u64 thmac;
 94			u8 hmac[MPTCPOPT_HMAC_LEN];
 95		};
 96	};
 97#endif
 98};
 99
100#define MPTCP_SCHED_NAME_MAX	16
101#define MPTCP_SCHED_MAX		128
102#define MPTCP_SCHED_BUF_MAX	(MPTCP_SCHED_NAME_MAX * MPTCP_SCHED_MAX)
103
104struct mptcp_sched_ops {
105	int (*get_send)(struct mptcp_sock *msk);
106	int (*get_retrans)(struct mptcp_sock *msk);
107
108	char			name[MPTCP_SCHED_NAME_MAX];
109	struct module		*owner;
110	struct list_head	list;
111
112	void (*init)(struct mptcp_sock *msk);
113	void (*release)(struct mptcp_sock *msk);
114} ____cacheline_aligned_in_smp;
115
116#define MPTCP_PM_NAME_MAX	16
117#define MPTCP_PM_MAX		128
118#define MPTCP_PM_BUF_MAX	(MPTCP_PM_NAME_MAX * MPTCP_PM_MAX)
119
120struct mptcp_pm_ops {
121	char			name[MPTCP_PM_NAME_MAX];
122	struct module		*owner;
123	struct list_head	list;
124
125	void (*init)(struct mptcp_sock *msk);
126	void (*release)(struct mptcp_sock *msk);
127} ____cacheline_aligned_in_smp;
128
129#ifdef CONFIG_MPTCP
130void mptcp_init(void);
131
132static inline bool sk_is_mptcp(const struct sock *sk)
133{
134	return tcp_sk(sk)->is_mptcp;
135}
136
137static inline bool rsk_is_mptcp(const struct request_sock *req)
138{
139	return tcp_rsk(req)->is_mptcp;
140}
141
142static inline bool rsk_drop_req(const struct request_sock *req)
143{
144	return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
145}
146
147void mptcp_space(const struct sock *ssk, int *space, int *full_space);
148bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
149		       unsigned int *size, struct mptcp_out_options *opts);
150bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
151			  struct mptcp_out_options *opts);
152bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
153			       unsigned int *size, unsigned int remaining,
154			       struct mptcp_out_options *opts);
155bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
156
157void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
158			 struct mptcp_out_options *opts);
159
160void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
161
162/* move the skb extension owership, with the assumption that 'to' is
163 * newly allocated
164 */
165static inline void mptcp_skb_ext_move(struct sk_buff *to,
166				      struct sk_buff *from)
167{
168	if (!skb_ext_exist(from, SKB_EXT_MPTCP))
169		return;
170
171	if (WARN_ON_ONCE(to->active_extensions))
172		skb_ext_put(to);
173
174	to->active_extensions = from->active_extensions;
175	to->extensions = from->extensions;
176	from->active_extensions = 0;
177}
178
179static inline void mptcp_skb_ext_copy(struct sk_buff *to,
180				      struct sk_buff *from)
181{
182	struct mptcp_ext *from_ext;
183
184	from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
185	if (!from_ext)
186		return;
187
188	from_ext->frozen = 1;
189	skb_ext_copy(to, from);
190}
191
192static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
193				     const struct mptcp_ext *from_ext)
194{
195	/* MPTCP always clears the ext when adding it to the skb, so
196	 * holes do not bother us here
197	 */
198	return !from_ext ||
199	       (to_ext && from_ext &&
200	        !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
201}
202
203/* check if skbs can be collapsed.
204 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
205 * mapping, or if the extension of @to is the same as @from.
206 * Collapsing is not possible if @to lacks an extension, but @from carries one.
207 */
208static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
209					  const struct sk_buff *from)
210{
211	return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
212				 skb_ext_find(from, SKB_EXT_MPTCP));
213}
214
215void mptcp_seq_show(struct seq_file *seq);
216int mptcp_subflow_init_cookie_req(struct request_sock *req,
217				  const struct sock *sk_listener,
218				  struct sk_buff *skb);
219struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
220					       struct sock *sk_listener,
221					       bool attach_listener);
222
223__be32 mptcp_get_reset_option(const struct sk_buff *skb);
224
225static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
226{
227	if (skb_ext_exist(skb, SKB_EXT_MPTCP))
228		return mptcp_get_reset_option(skb);
229
230	return htonl(0u);
231}
232
233void mptcp_active_detect_blackhole(struct sock *sk, bool expired);
234#else
235
236static inline void mptcp_init(void)
237{
238}
239
240static inline bool sk_is_mptcp(const struct sock *sk)
241{
242	return false;
243}
244
245static inline bool rsk_is_mptcp(const struct request_sock *req)
246{
247	return false;
248}
249
250static inline bool rsk_drop_req(const struct request_sock *req)
251{
252	return false;
253}
254
255static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
256				     unsigned int *size,
257				     struct mptcp_out_options *opts)
258{
259	return false;
260}
261
262static inline bool mptcp_synack_options(const struct request_sock *req,
263					unsigned int *size,
264					struct mptcp_out_options *opts)
265{
266	return false;
267}
268
269static inline bool mptcp_established_options(struct sock *sk,
270					     struct sk_buff *skb,
271					     unsigned int *size,
272					     unsigned int remaining,
273					     struct mptcp_out_options *opts)
274{
275	return false;
276}
277
278static inline bool mptcp_incoming_options(struct sock *sk,
279					  struct sk_buff *skb)
280{
281	return true;
282}
283
284static inline void mptcp_skb_ext_move(struct sk_buff *to,
285				      const struct sk_buff *from)
286{
287}
288
289static inline void mptcp_skb_ext_copy(struct sk_buff *to,
290				      struct sk_buff *from)
291{
292}
293
294static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
295					  const struct sk_buff *from)
296{
297	return true;
298}
299
300static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
301static inline void mptcp_seq_show(struct seq_file *seq) { }
302
303static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
304						const struct sock *sk_listener,
305						struct sk_buff *skb)
306{
307	return 0; /* TCP fallback */
308}
309
310static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
311							     struct sock *sk_listener,
312							     bool attach_listener)
313{
314	return NULL;
315}
316
317static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
318
319static inline void mptcp_active_detect_blackhole(struct sock *sk, bool expired) { }
320#endif /* CONFIG_MPTCP */
321
322#if IS_ENABLED(CONFIG_MPTCP_IPV6)
323int mptcpv6_init(void);
324void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
325#elif IS_ENABLED(CONFIG_IPV6)
326static inline int mptcpv6_init(void) { return 0; }
327static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
328#endif
329
330#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
331struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
332#else
333static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
334#endif
335
336#if !IS_ENABLED(CONFIG_MPTCP)
337struct mptcp_sock { };
338#endif
339
340#endif /* __NET_MPTCP_H */