xref: /linux-6.15/include/linux/sunrpc/xprt.h (revision a671de08)
1 /*
2  *  linux/include/linux/sunrpc/xprt.h
3  *
4  *  Declarations for the RPC transport interface.
5  *
6  *  Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
7  */
8 
9 #ifndef _LINUX_SUNRPC_XPRT_H
10 #define _LINUX_SUNRPC_XPRT_H
11 
12 #include <linux/uio.h>
13 #include <linux/socket.h>
14 #include <linux/in.h>
15 #include <linux/ktime.h>
16 #include <linux/sunrpc/sched.h>
17 #include <linux/sunrpc/xdr.h>
18 #include <linux/sunrpc/msg_prot.h>
19 
20 #ifdef __KERNEL__
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 /*
28  * This describes a timeout strategy
29  */
30 struct rpc_timeout {
31 	unsigned long		to_initval,		/* initial timeout */
32 				to_maxval,		/* max timeout */
33 				to_increment;		/* if !exponential */
34 	unsigned int		to_retries;		/* max # of retries */
35 	unsigned char		to_exponential;
36 };
37 
38 enum rpc_display_format_t {
39 	RPC_DISPLAY_ADDR = 0,
40 	RPC_DISPLAY_PORT,
41 	RPC_DISPLAY_PROTO,
42 	RPC_DISPLAY_HEX_ADDR,
43 	RPC_DISPLAY_HEX_PORT,
44 	RPC_DISPLAY_NETID,
45 	RPC_DISPLAY_MAX,
46 };
47 
48 struct rpc_task;
49 struct rpc_xprt;
50 struct seq_file;
51 
52 /*
53  * This describes a complete RPC request
54  */
55 struct rpc_rqst {
56 	/*
57 	 * This is the user-visible part
58 	 */
59 	struct rpc_xprt *	rq_xprt;		/* RPC client */
60 	struct xdr_buf		rq_snd_buf;		/* send buffer */
61 	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
62 
63 	/*
64 	 * This is the private part
65 	 */
66 	struct rpc_task *	rq_task;	/* RPC task data */
67 	struct rpc_cred *	rq_cred;	/* Bound cred */
68 	__be32			rq_xid;		/* request XID */
69 	int			rq_cong;	/* has incremented xprt->cong */
70 	u32			rq_seqno;	/* gss seq no. used on req. */
71 	int			rq_enc_pages_num;
72 	struct page		**rq_enc_pages;	/* scratch pages for use by
73 						   gss privacy code */
74 	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
75 	struct list_head	rq_list;
76 
77 	__u32 *			rq_buffer;	/* XDR encode buffer */
78 	size_t			rq_callsize,
79 				rq_rcvsize;
80 	size_t			rq_xmit_bytes_sent;	/* total bytes sent */
81 	size_t			rq_reply_bytes_recvd;	/* total reply bytes */
82 							/* received */
83 
84 	struct xdr_buf		rq_private_buf;		/* The receive buffer
85 							 * used in the softirq.
86 							 */
87 	unsigned long		rq_majortimeo;	/* major timeout alarm */
88 	unsigned long		rq_timeout;	/* Current timeout value */
89 	ktime_t			rq_rtt;		/* round-trip time */
90 	unsigned int		rq_retries;	/* # of retries */
91 	unsigned int		rq_connect_cookie;
92 						/* A cookie used to track the
93 						   state of the transport
94 						   connection */
95 
96 	/*
97 	 * Partial send handling
98 	 */
99 	u32			rq_bytes_sent;	/* Bytes we have sent */
100 
101 	ktime_t			rq_xtime;	/* transmit time stamp */
102 	int			rq_ntrans;
103 
104 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
105 	struct list_head	rq_bc_list;	/* Callback service list */
106 	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
107 	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */
108 #endif /* CONFIG_SUNRPC_BACKCHANEL */
109 };
110 #define rq_svec			rq_snd_buf.head
111 #define rq_slen			rq_snd_buf.len
112 
113 struct rpc_xprt_ops {
114 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
115 	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
116 	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
117 	void		(*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
118 	void		(*rpcbind)(struct rpc_task *task);
119 	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);
120 	void		(*connect)(struct rpc_task *task);
121 	void *		(*buf_alloc)(struct rpc_task *task, size_t size);
122 	void		(*buf_free)(void *buffer);
123 	int		(*send_request)(struct rpc_task *task);
124 	void		(*set_retrans_timeout)(struct rpc_task *task);
125 	void		(*timer)(struct rpc_task *task);
126 	void		(*release_request)(struct rpc_task *task);
127 	void		(*close)(struct rpc_xprt *xprt);
128 	void		(*destroy)(struct rpc_xprt *xprt);
129 	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
130 };
131 
132 /*
133  * RPC transport identifiers
134  *
135  * To preserve compatibility with the historical use of raw IP protocol
136  * id's for transport selection, UDP and TCP identifiers are specified
137  * with the previous values. No such restriction exists for new transports,
138  * except that they may not collide with these values (17 and 6,
139  * respectively).
140  */
141 #define XPRT_TRANSPORT_BC       (1 << 31)
142 enum xprt_transports {
143 	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
144 	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
145 	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,
146 	XPRT_TRANSPORT_RDMA	= 256,
147 	XPRT_TRANSPORT_LOCAL	= 257,
148 };
149 
150 struct rpc_xprt {
151 	atomic_t		count;		/* Reference count */
152 	struct rpc_xprt_ops *	ops;		/* transport methods */
153 
154 	const struct rpc_timeout *timeout;	/* timeout parms */
155 	struct sockaddr_storage	addr;		/* server address */
156 	size_t			addrlen;	/* size of server address */
157 	int			prot;		/* IP protocol */
158 
159 	unsigned long		cong;		/* current congestion */
160 	unsigned long		cwnd;		/* congestion window */
161 
162 	size_t			max_payload;	/* largest RPC payload size,
163 						   in bytes */
164 	unsigned int		tsh_size;	/* size of transport specific
165 						   header */
166 
167 	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */
168 	struct rpc_wait_queue	sending;	/* requests waiting to send */
169 	struct rpc_wait_queue	pending;	/* requests in flight */
170 	struct rpc_wait_queue	backlog;	/* waiting for slot */
171 	struct list_head	free;		/* free slots */
172 	unsigned int		max_reqs;	/* max number of slots */
173 	unsigned int		min_reqs;	/* min number of slots */
174 	atomic_t		num_reqs;	/* total slots */
175 	unsigned long		state;		/* transport state */
176 	unsigned char		resvport   : 1; /* use a reserved port */
177 	unsigned int		swapper;	/* we're swapping over this
178 						   transport */
179 	unsigned int		bind_index;	/* bind function index */
180 
181 	/*
182 	 * Connection of transports
183 	 */
184 	unsigned long		bind_timeout,
185 				reestablish_timeout;
186 	unsigned int		connect_cookie;	/* A cookie that gets bumped
187 						   every time the transport
188 						   is reconnected */
189 
190 	/*
191 	 * Disconnection of idle transports
192 	 */
193 	struct work_struct	task_cleanup;
194 	struct timer_list	timer;
195 	unsigned long		last_used,
196 				idle_timeout;
197 
198 	/*
199 	 * Send stuff
200 	 */
201 	spinlock_t		transport_lock;	/* lock transport info */
202 	spinlock_t		reserve_lock;	/* lock slot table */
203 	u32			xid;		/* Next XID value to use */
204 	struct rpc_task *	snd_task;	/* Task blocked in send */
205 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
206 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
207 	struct svc_serv		*bc_serv;       /* The RPC service which will */
208 						/* process the callback */
209 	unsigned int		bc_alloc_count;	/* Total number of preallocs */
210 	spinlock_t		bc_pa_lock;	/* Protects the preallocated
211 						 * items */
212 	struct list_head	bc_pa_list;	/* List of preallocated
213 						 * backchannel rpc_rqst's */
214 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
215 	struct list_head	recv;
216 
217 	struct {
218 		unsigned long		bind_count,	/* total number of binds */
219 					connect_count,	/* total number of connects */
220 					connect_start,	/* connect start timestamp */
221 					connect_time,	/* jiffies waiting for connect */
222 					sends,		/* how many complete requests */
223 					recvs,		/* how many complete requests */
224 					bad_xids,	/* lookup_rqst didn't find XID */
225 					max_slots;	/* max rpc_slots used */
226 
227 		unsigned long long	req_u,		/* average requests on the wire */
228 					bklog_u,	/* backlog queue utilization */
229 					sending_u,	/* send q utilization */
230 					pending_u;	/* pend q utilization */
231 	} stat;
232 
233 	struct net		*xprt_net;
234 	const char		*servername;
235 	const char		*address_strings[RPC_DISPLAY_MAX];
236 };
237 
238 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
239 /*
240  * Backchannel flags
241  */
242 #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
243 						/* buffer in use */
244 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
245 
246 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
247 static inline int bc_prealloc(struct rpc_rqst *req)
248 {
249 	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
250 }
251 #else
252 static inline int bc_prealloc(struct rpc_rqst *req)
253 {
254 	return 0;
255 }
256 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
257 
258 struct xprt_create {
259 	int			ident;		/* XPRT_TRANSPORT identifier */
260 	struct net *		net;
261 	struct sockaddr *	srcaddr;	/* optional local address */
262 	struct sockaddr *	dstaddr;	/* remote peer address */
263 	size_t			addrlen;
264 	const char		*servername;
265 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
266 };
267 
268 struct xprt_class {
269 	struct list_head	list;
270 	int			ident;		/* XPRT_TRANSPORT identifier */
271 	struct rpc_xprt *	(*setup)(struct xprt_create *);
272 	struct module		*owner;
273 	char			name[32];
274 };
275 
276 /*
277  * Generic internal transport functions
278  */
279 struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
280 void			xprt_connect(struct rpc_task *task);
281 void			xprt_reserve(struct rpc_task *task);
282 int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
283 int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
284 void			xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
285 void			xprt_lock_and_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
286 int			xprt_prepare_transmit(struct rpc_task *task);
287 void			xprt_transmit(struct rpc_task *task);
288 void			xprt_end_transmit(struct rpc_task *task);
289 int			xprt_adjust_timeout(struct rpc_rqst *req);
290 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
291 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
292 void			xprt_release(struct rpc_task *task);
293 struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
294 void			xprt_put(struct rpc_xprt *xprt);
295 struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
296 				unsigned int num_prealloc,
297 				unsigned int max_req);
298 void			xprt_free(struct rpc_xprt *);
299 
300 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
301 {
302 	return p + xprt->tsh_size;
303 }
304 
305 /*
306  * Transport switch helper functions
307  */
308 int			xprt_register_transport(struct xprt_class *type);
309 int			xprt_unregister_transport(struct xprt_class *type);
310 int			xprt_load_transport(const char *);
311 void			xprt_set_retrans_timeout_def(struct rpc_task *task);
312 void			xprt_set_retrans_timeout_rtt(struct rpc_task *task);
313 void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
314 void			xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
315 void			xprt_write_space(struct rpc_xprt *xprt);
316 void			xprt_adjust_cwnd(struct rpc_task *task, int result);
317 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
318 void			xprt_complete_rqst(struct rpc_task *task, int copied);
319 void			xprt_release_rqst_cong(struct rpc_task *task);
320 void			xprt_disconnect_done(struct rpc_xprt *xprt);
321 void			xprt_force_disconnect(struct rpc_xprt *xprt);
322 void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
323 int			xs_swapper(struct rpc_xprt *xprt, int enable);
324 
325 /*
326  * Reserved bit positions in xprt->state
327  */
328 #define XPRT_LOCKED		(0)
329 #define XPRT_CONNECTED		(1)
330 #define XPRT_CONNECTING		(2)
331 #define XPRT_CLOSE_WAIT		(3)
332 #define XPRT_BOUND		(4)
333 #define XPRT_BINDING		(5)
334 #define XPRT_CLOSING		(6)
335 #define XPRT_CONNECTION_ABORT	(7)
336 #define XPRT_CONNECTION_CLOSE	(8)
337 
338 static inline void xprt_set_connected(struct rpc_xprt *xprt)
339 {
340 	set_bit(XPRT_CONNECTED, &xprt->state);
341 }
342 
343 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
344 {
345 	clear_bit(XPRT_CONNECTED, &xprt->state);
346 }
347 
348 static inline int xprt_connected(struct rpc_xprt *xprt)
349 {
350 	return test_bit(XPRT_CONNECTED, &xprt->state);
351 }
352 
353 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
354 {
355 	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
356 }
357 
358 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
359 {
360 	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
361 }
362 
363 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
364 {
365 	smp_mb__before_clear_bit();
366 	clear_bit(XPRT_CONNECTING, &xprt->state);
367 	smp_mb__after_clear_bit();
368 }
369 
370 static inline int xprt_connecting(struct rpc_xprt *xprt)
371 {
372 	return test_bit(XPRT_CONNECTING, &xprt->state);
373 }
374 
375 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
376 {
377 	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
378 }
379 
380 static inline void xprt_set_bound(struct rpc_xprt *xprt)
381 {
382 	test_and_set_bit(XPRT_BOUND, &xprt->state);
383 }
384 
385 static inline int xprt_bound(struct rpc_xprt *xprt)
386 {
387 	return test_bit(XPRT_BOUND, &xprt->state);
388 }
389 
390 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
391 {
392 	clear_bit(XPRT_BOUND, &xprt->state);
393 }
394 
395 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
396 {
397 	smp_mb__before_clear_bit();
398 	clear_bit(XPRT_BINDING, &xprt->state);
399 	smp_mb__after_clear_bit();
400 }
401 
402 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
403 {
404 	return test_and_set_bit(XPRT_BINDING, &xprt->state);
405 }
406 
407 #endif /* __KERNEL__*/
408 
409 #endif /* _LINUX_SUNRPC_XPRT_H */
410