1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *  linux/include/linux/sunrpc/xprt.h
4  *
5  *  Declarations for the RPC transport interface.
6  *
7  *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8  */
9 
10 #ifndef _LINUX_SUNRPC_XPRT_H
11 #define _LINUX_SUNRPC_XPRT_H
12 
13 #include <linux/uio.h>
14 #include <linux/socket.h>
15 #include <linux/in.h>
16 #include <linux/ktime.h>
17 #include <linux/kref.h>
18 #include <linux/sunrpc/sched.h>
19 #include <linux/sunrpc/xdr.h>
20 #include <linux/sunrpc/msg_prot.h>
21 
22 #define RPC_MIN_SLOT_TABLE	(2U)
23 #define RPC_DEF_SLOT_TABLE	(16U)
24 #define RPC_MAX_SLOT_TABLE_LIMIT	(65536U)
25 #define RPC_MAX_SLOT_TABLE	RPC_MAX_SLOT_TABLE_LIMIT
26 
27 #define RPC_CWNDSHIFT		(8U)
28 #define RPC_CWNDSCALE		(1U << RPC_CWNDSHIFT)
29 #define RPC_INITCWND		RPC_CWNDSCALE
30 #define RPC_MAXCWND(xprt)	((xprt)->max_reqs << RPC_CWNDSHIFT)
31 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
32 
33 /*
34  * This describes a timeout strategy
35  */
36 struct rpc_timeout {
37 	unsigned long		to_initval,		/* initial timeout */
38 				to_maxval,		/* max timeout */
39 				to_increment;		/* if !exponential */
40 	unsigned int		to_retries;		/* max # of retries */
41 	unsigned char		to_exponential;
42 };
43 
44 enum rpc_display_format_t {
45 	RPC_DISPLAY_ADDR = 0,
46 	RPC_DISPLAY_PORT,
47 	RPC_DISPLAY_PROTO,
48 	RPC_DISPLAY_HEX_ADDR,
49 	RPC_DISPLAY_HEX_PORT,
50 	RPC_DISPLAY_NETID,
51 	RPC_DISPLAY_MAX,
52 };
53 
54 struct rpc_task;
55 struct rpc_xprt;
56 struct xprt_class;
57 struct seq_file;
58 struct svc_serv;
59 struct net;
60 
61 /*
62  * This describes a complete RPC request
63  */
64 struct rpc_rqst {
65 	/*
66 	 * This is the user-visible part
67 	 */
68 	struct rpc_xprt *	rq_xprt;		/* RPC client */
69 	struct xdr_buf		rq_snd_buf;		/* send buffer */
70 	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
71 
72 	/*
73 	 * This is the private part
74 	 */
75 	struct rpc_task *	rq_task;	/* RPC task data */
76 	struct rpc_cred *	rq_cred;	/* Bound cred */
77 	__be32			rq_xid;		/* request XID */
78 	int			rq_cong;	/* has incremented xprt->cong */
79 	u32			rq_seqno;	/* gss seq no. used on req. */
80 	int			rq_enc_pages_num;
81 	struct page		**rq_enc_pages;	/* scratch pages for use by
82 						   gss privacy code */
83 	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
84 
85 	union {
86 		struct list_head	rq_list;	/* Slot allocation list */
87 		struct rb_node		rq_recv;	/* Receive queue */
88 	};
89 
90 	struct list_head	rq_xmit;	/* Send queue */
91 	struct list_head	rq_xmit2;	/* Send queue */
92 
93 	void			*rq_buffer;	/* Call XDR encode buffer */
94 	size_t			rq_callsize;
95 	void			*rq_rbuffer;	/* Reply XDR decode buffer */
96 	size_t			rq_rcvsize;
97 	size_t			rq_xmit_bytes_sent;	/* total bytes sent */
98 	size_t			rq_reply_bytes_recvd;	/* total reply bytes */
99 							/* received */
100 
101 	struct xdr_buf		rq_private_buf;		/* The receive buffer
102 							 * used in the softirq.
103 							 */
104 	unsigned long		rq_majortimeo;	/* major timeout alarm */
105 	unsigned long		rq_minortimeo;	/* minor timeout alarm */
106 	unsigned long		rq_timeout;	/* Current timeout value */
107 	ktime_t			rq_rtt;		/* round-trip time */
108 	unsigned int		rq_retries;	/* # of retries */
109 	unsigned int		rq_connect_cookie;
110 						/* A cookie used to track the
111 						   state of the transport
112 						   connection */
113 	atomic_t		rq_pin;
114 
115 	/*
116 	 * Partial send handling
117 	 */
118 	u32			rq_bytes_sent;	/* Bytes we have sent */
119 
120 	ktime_t			rq_xtime;	/* transmit time stamp */
121 	int			rq_ntrans;
122 
123 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
124 	struct list_head	rq_bc_list;	/* Callback service list */
125 	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
126 	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */
127 #endif /* CONFIG_SUNRPC_BACKCHANEL */
128 };
129 #define rq_svec			rq_snd_buf.head
130 #define rq_slen			rq_snd_buf.len
131 
132 struct rpc_xprt_ops {
133 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
134 	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
135 	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
136 	void		(*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
137 	void		(*free_slot)(struct rpc_xprt *xprt,
138 				     struct rpc_rqst *req);
139 	void		(*rpcbind)(struct rpc_task *task);
140 	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);
141 	void		(*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
142 	int		(*buf_alloc)(struct rpc_task *task);
143 	void		(*buf_free)(struct rpc_task *task);
144 	void		(*prepare_request)(struct rpc_rqst *req);
145 	int		(*send_request)(struct rpc_rqst *req);
146 	void		(*wait_for_reply_request)(struct rpc_task *task);
147 	void		(*timer)(struct rpc_xprt *xprt, struct rpc_task *task);
148 	void		(*release_request)(struct rpc_task *task);
149 	void		(*close)(struct rpc_xprt *xprt);
150 	void		(*destroy)(struct rpc_xprt *xprt);
151 	void		(*set_connect_timeout)(struct rpc_xprt *xprt,
152 					unsigned long connect_timeout,
153 					unsigned long reconnect_timeout);
154 	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
155 	int		(*enable_swap)(struct rpc_xprt *xprt);
156 	void		(*disable_swap)(struct rpc_xprt *xprt);
157 	void		(*inject_disconnect)(struct rpc_xprt *xprt);
158 	int		(*bc_setup)(struct rpc_xprt *xprt,
159 				    unsigned int min_reqs);
160 	size_t		(*bc_maxpayload)(struct rpc_xprt *xprt);
161 	unsigned int	(*bc_num_slots)(struct rpc_xprt *xprt);
162 	void		(*bc_free_rqst)(struct rpc_rqst *rqst);
163 	void		(*bc_destroy)(struct rpc_xprt *xprt,
164 				      unsigned int max_reqs);
165 };
166 
167 /*
168  * RPC transport identifiers
169  *
170  * To preserve compatibility with the historical use of raw IP protocol
171  * id's for transport selection, UDP and TCP identifiers are specified
172  * with the previous values. No such restriction exists for new transports,
173  * except that they may not collide with these values (17 and 6,
174  * respectively).
175  */
176 #define XPRT_TRANSPORT_BC       (1 << 31)
177 enum xprt_transports {
178 	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
179 	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
180 	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,
181 	XPRT_TRANSPORT_RDMA	= 256,
182 	XPRT_TRANSPORT_BC_RDMA	= XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
183 	XPRT_TRANSPORT_LOCAL	= 257,
184 };
185 
186 struct rpc_sysfs_xprt;
187 struct rpc_xprt {
188 	struct kref		kref;		/* Reference count */
189 	const struct rpc_xprt_ops *ops;		/* transport methods */
190 	unsigned int		id;		/* transport id */
191 
192 	const struct rpc_timeout *timeout;	/* timeout parms */
193 	struct sockaddr_storage	addr;		/* server address */
194 	size_t			addrlen;	/* size of server address */
195 	int			prot;		/* IP protocol */
196 
197 	unsigned long		cong;		/* current congestion */
198 	unsigned long		cwnd;		/* congestion window */
199 
200 	size_t			max_payload;	/* largest RPC payload size,
201 						   in bytes */
202 
203 	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */
204 	struct rpc_wait_queue	sending;	/* requests waiting to send */
205 	struct rpc_wait_queue	pending;	/* requests in flight */
206 	struct rpc_wait_queue	backlog;	/* waiting for slot */
207 	struct list_head	free;		/* free slots */
208 	unsigned int		max_reqs;	/* max number of slots */
209 	unsigned int		min_reqs;	/* min number of slots */
210 	unsigned int		num_reqs;	/* total slots */
211 	unsigned long		state;		/* transport state */
212 	unsigned char		resvport   : 1,	/* use a reserved port */
213 				reuseport  : 1; /* reuse port on reconnect */
214 	atomic_t		swapper;	/* we're swapping over this
215 						   transport */
216 	unsigned int		bind_index;	/* bind function index */
217 
218 	/*
219 	 * Multipath
220 	 */
221 	struct list_head	xprt_switch;
222 
223 	/*
224 	 * Connection of transports
225 	 */
226 	unsigned long		bind_timeout,
227 				reestablish_timeout;
228 	unsigned int		connect_cookie;	/* A cookie that gets bumped
229 						   every time the transport
230 						   is reconnected */
231 
232 	/*
233 	 * Disconnection of idle transports
234 	 */
235 	struct work_struct	task_cleanup;
236 	struct timer_list	timer;
237 	unsigned long		last_used,
238 				idle_timeout,
239 				connect_timeout,
240 				max_reconnect_timeout;
241 
242 	/*
243 	 * Send stuff
244 	 */
245 	atomic_long_t		queuelen;
246 	spinlock_t		transport_lock;	/* lock transport info */
247 	spinlock_t		reserve_lock;	/* lock slot table */
248 	spinlock_t		queue_lock;	/* send/receive queue lock */
249 	u32			xid;		/* Next XID value to use */
250 	struct rpc_task *	snd_task;	/* Task blocked in send */
251 
252 	struct list_head	xmit_queue;	/* Send queue */
253 	atomic_long_t		xmit_queuelen;
254 
255 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
256 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
257 	struct svc_serv		*bc_serv;       /* The RPC service which will */
258 						/* process the callback */
259 	unsigned int		bc_alloc_max;
260 	unsigned int		bc_alloc_count;	/* Total number of preallocs */
261 	atomic_t		bc_slot_count;	/* Number of allocated slots */
262 	spinlock_t		bc_pa_lock;	/* Protects the preallocated
263 						 * items */
264 	struct list_head	bc_pa_list;	/* List of preallocated
265 						 * backchannel rpc_rqst's */
266 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
267 
268 	struct rb_root		recv_queue;	/* Receive queue */
269 
270 	struct {
271 		unsigned long		bind_count,	/* total number of binds */
272 					connect_count,	/* total number of connects */
273 					connect_start,	/* connect start timestamp */
274 					connect_time,	/* jiffies waiting for connect */
275 					sends,		/* how many complete requests */
276 					recvs,		/* how many complete requests */
277 					bad_xids,	/* lookup_rqst didn't find XID */
278 					max_slots;	/* max rpc_slots used */
279 
280 		unsigned long long	req_u,		/* average requests on the wire */
281 					bklog_u,	/* backlog queue utilization */
282 					sending_u,	/* send q utilization */
283 					pending_u;	/* pend q utilization */
284 	} stat;
285 
286 	struct net		*xprt_net;
287 	const char		*servername;
288 	const char		*address_strings[RPC_DISPLAY_MAX];
289 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
290 	struct dentry		*debugfs;		/* debugfs directory */
291 #endif
292 	struct rcu_head		rcu;
293 	const struct xprt_class	*xprt_class;
294 	struct rpc_sysfs_xprt	*xprt_sysfs;
295 	bool			main; /*mark if this is the 1st transport */
296 };
297 
298 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
299 /*
300  * Backchannel flags
301  */
302 #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
303 						/* buffer in use */
304 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
305 
306 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
bc_prealloc(struct rpc_rqst * req)307 static inline int bc_prealloc(struct rpc_rqst *req)
308 {
309 	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
310 }
311 #else
bc_prealloc(struct rpc_rqst * req)312 static inline int bc_prealloc(struct rpc_rqst *req)
313 {
314 	return 0;
315 }
316 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
317 
318 #define XPRT_CREATE_INFINITE_SLOTS	(1U)
319 #define XPRT_CREATE_NO_IDLE_TIMEOUT	(1U << 1)
320 
321 struct xprt_create {
322 	int			ident;		/* XPRT_TRANSPORT identifier */
323 	struct net *		net;
324 	struct sockaddr *	srcaddr;	/* optional local address */
325 	struct sockaddr *	dstaddr;	/* remote peer address */
326 	size_t			addrlen;
327 	const char		*servername;
328 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
329 	struct rpc_xprt_switch	*bc_xps;
330 	unsigned int		flags;
331 };
332 
333 struct xprt_class {
334 	struct list_head	list;
335 	int			ident;		/* XPRT_TRANSPORT identifier */
336 	struct rpc_xprt *	(*setup)(struct xprt_create *);
337 	struct module		*owner;
338 	char			name[32];
339 	const char *		netid[];
340 };
341 
342 /*
343  * Generic internal transport functions
344  */
345 struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
346 void			xprt_connect(struct rpc_task *task);
347 unsigned long		xprt_reconnect_delay(const struct rpc_xprt *xprt);
348 void			xprt_reconnect_backoff(struct rpc_xprt *xprt,
349 					       unsigned long init_to);
350 void			xprt_reserve(struct rpc_task *task);
351 void			xprt_retry_reserve(struct rpc_task *task);
352 int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
353 int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
354 void			xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
355 void			xprt_free_slot(struct rpc_xprt *xprt,
356 				       struct rpc_rqst *req);
357 void			xprt_request_prepare(struct rpc_rqst *req);
358 bool			xprt_prepare_transmit(struct rpc_task *task);
359 void			xprt_request_enqueue_transmit(struct rpc_task *task);
360 void			xprt_request_enqueue_receive(struct rpc_task *task);
361 void			xprt_request_wait_receive(struct rpc_task *task);
362 void			xprt_request_dequeue_xprt(struct rpc_task *task);
363 bool			xprt_request_need_retransmit(struct rpc_task *task);
364 void			xprt_transmit(struct rpc_task *task);
365 void			xprt_end_transmit(struct rpc_task *task);
366 int			xprt_adjust_timeout(struct rpc_rqst *req);
367 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
368 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
369 void			xprt_release(struct rpc_task *task);
370 struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
371 void			xprt_put(struct rpc_xprt *xprt);
372 struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
373 				unsigned int num_prealloc,
374 				unsigned int max_req);
375 void			xprt_free(struct rpc_xprt *);
376 void			xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task);
377 bool			xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req);
378 void			xprt_cleanup_ids(void);
379 
380 static inline int
xprt_enable_swap(struct rpc_xprt * xprt)381 xprt_enable_swap(struct rpc_xprt *xprt)
382 {
383 	return xprt->ops->enable_swap(xprt);
384 }
385 
386 static inline void
xprt_disable_swap(struct rpc_xprt * xprt)387 xprt_disable_swap(struct rpc_xprt *xprt)
388 {
389 	xprt->ops->disable_swap(xprt);
390 }
391 
392 /*
393  * Transport switch helper functions
394  */
395 int			xprt_register_transport(struct xprt_class *type);
396 int			xprt_unregister_transport(struct xprt_class *type);
397 int			xprt_find_transport_ident(const char *);
398 void			xprt_wait_for_reply_request_def(struct rpc_task *task);
399 void			xprt_wait_for_reply_request_rtt(struct rpc_task *task);
400 void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
401 void			xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
402 bool			xprt_write_space(struct rpc_xprt *xprt);
403 void			xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
404 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
405 void			xprt_update_rtt(struct rpc_task *task);
406 void			xprt_complete_rqst(struct rpc_task *task, int copied);
407 void			xprt_pin_rqst(struct rpc_rqst *req);
408 void			xprt_unpin_rqst(struct rpc_rqst *req);
409 void			xprt_release_rqst_cong(struct rpc_task *task);
410 bool			xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
411 void			xprt_disconnect_done(struct rpc_xprt *xprt);
412 void			xprt_force_disconnect(struct rpc_xprt *xprt);
413 void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
414 
415 bool			xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
416 void			xprt_unlock_connect(struct rpc_xprt *, void *);
417 void			xprt_release_write(struct rpc_xprt *, struct rpc_task *);
418 
419 /*
420  * Reserved bit positions in xprt->state
421  */
422 #define XPRT_LOCKED		(0)
423 #define XPRT_CONNECTED		(1)
424 #define XPRT_CONNECTING		(2)
425 #define XPRT_CLOSE_WAIT		(3)
426 #define XPRT_BOUND		(4)
427 #define XPRT_BINDING		(5)
428 #define XPRT_CLOSING		(6)
429 #define XPRT_OFFLINE		(7)
430 #define XPRT_REMOVE		(8)
431 #define XPRT_CONGESTED		(9)
432 #define XPRT_CWND_WAIT		(10)
433 #define XPRT_WRITE_SPACE	(11)
434 #define XPRT_SND_IS_COOKIE	(12)
435 
xprt_set_connected(struct rpc_xprt * xprt)436 static inline void xprt_set_connected(struct rpc_xprt *xprt)
437 {
438 	set_bit(XPRT_CONNECTED, &xprt->state);
439 }
440 
xprt_clear_connected(struct rpc_xprt * xprt)441 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
442 {
443 	clear_bit(XPRT_CONNECTED, &xprt->state);
444 }
445 
xprt_connected(struct rpc_xprt * xprt)446 static inline int xprt_connected(struct rpc_xprt *xprt)
447 {
448 	return test_bit(XPRT_CONNECTED, &xprt->state);
449 }
450 
xprt_test_and_set_connected(struct rpc_xprt * xprt)451 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
452 {
453 	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
454 }
455 
xprt_test_and_clear_connected(struct rpc_xprt * xprt)456 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
457 {
458 	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
459 }
460 
xprt_clear_connecting(struct rpc_xprt * xprt)461 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
462 {
463 	smp_mb__before_atomic();
464 	clear_bit(XPRT_CONNECTING, &xprt->state);
465 	smp_mb__after_atomic();
466 }
467 
xprt_connecting(struct rpc_xprt * xprt)468 static inline int xprt_connecting(struct rpc_xprt *xprt)
469 {
470 	return test_bit(XPRT_CONNECTING, &xprt->state);
471 }
472 
xprt_test_and_set_connecting(struct rpc_xprt * xprt)473 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
474 {
475 	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
476 }
477 
xprt_set_bound(struct rpc_xprt * xprt)478 static inline void xprt_set_bound(struct rpc_xprt *xprt)
479 {
480 	test_and_set_bit(XPRT_BOUND, &xprt->state);
481 }
482 
xprt_bound(struct rpc_xprt * xprt)483 static inline int xprt_bound(struct rpc_xprt *xprt)
484 {
485 	return test_bit(XPRT_BOUND, &xprt->state);
486 }
487 
xprt_clear_bound(struct rpc_xprt * xprt)488 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
489 {
490 	clear_bit(XPRT_BOUND, &xprt->state);
491 }
492 
xprt_clear_binding(struct rpc_xprt * xprt)493 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
494 {
495 	smp_mb__before_atomic();
496 	clear_bit(XPRT_BINDING, &xprt->state);
497 	smp_mb__after_atomic();
498 }
499 
xprt_test_and_set_binding(struct rpc_xprt * xprt)500 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
501 {
502 	return test_and_set_bit(XPRT_BINDING, &xprt->state);
503 }
504 
505 #endif /* _LINUX_SUNRPC_XPRT_H */
506