xref: /linux-6.15/include/linux/sunrpc/xprt.h (revision bcefe12e)
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/kref.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	(128U)
25 
26 /*
27  * This describes a timeout strategy
28  */
29 struct rpc_timeout {
30 	unsigned long		to_initval,		/* initial timeout */
31 				to_maxval,		/* max timeout */
32 				to_increment;		/* if !exponential */
33 	unsigned int		to_retries;		/* max # of retries */
34 	unsigned char		to_exponential;
35 };
36 
37 enum rpc_display_format_t {
38 	RPC_DISPLAY_ADDR = 0,
39 	RPC_DISPLAY_PORT,
40 	RPC_DISPLAY_PROTO,
41 	RPC_DISPLAY_HEX_ADDR,
42 	RPC_DISPLAY_HEX_PORT,
43 	RPC_DISPLAY_NETID,
44 	RPC_DISPLAY_MAX,
45 };
46 
47 struct rpc_task;
48 struct rpc_xprt;
49 struct seq_file;
50 
51 /*
52  * This describes a complete RPC request
53  */
54 struct rpc_rqst {
55 	/*
56 	 * This is the user-visible part
57 	 */
58 	struct rpc_xprt *	rq_xprt;		/* RPC client */
59 	struct xdr_buf		rq_snd_buf;		/* send buffer */
60 	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
61 
62 	/*
63 	 * This is the private part
64 	 */
65 	struct rpc_task *	rq_task;	/* RPC task data */
66 	__be32			rq_xid;		/* request XID */
67 	int			rq_cong;	/* has incremented xprt->cong */
68 	int			rq_reply_bytes_recvd;	/* number of reply */
69 							/* bytes received */
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 
81 	struct xdr_buf		rq_private_buf;		/* The receive buffer
82 							 * used in the softirq.
83 							 */
84 	unsigned long		rq_majortimeo;	/* major timeout alarm */
85 	unsigned long		rq_timeout;	/* Current timeout value */
86 	unsigned int		rq_retries;	/* # of retries */
87 	unsigned int		rq_connect_cookie;
88 						/* A cookie used to track the
89 						   state of the transport
90 						   connection */
91 
92 	/*
93 	 * Partial send handling
94 	 */
95 	u32			rq_bytes_sent;	/* Bytes we have sent */
96 
97 	unsigned long		rq_xtime;	/* when transmitted */
98 	int			rq_ntrans;
99 
100 #if defined(CONFIG_NFS_V4_1)
101 	struct list_head	rq_bc_list;	/* Callback service list */
102 	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
103 	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */
104 #endif /* CONFIG_NFS_V4_1 */
105 };
106 #define rq_svec			rq_snd_buf.head
107 #define rq_slen			rq_snd_buf.len
108 
109 struct rpc_xprt_ops {
110 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
111 	int		(*reserve_xprt)(struct rpc_task *task);
112 	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
113 	void		(*rpcbind)(struct rpc_task *task);
114 	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);
115 	void		(*connect)(struct rpc_task *task);
116 	void *		(*buf_alloc)(struct rpc_task *task, size_t size);
117 	void		(*buf_free)(void *buffer);
118 	int		(*send_request)(struct rpc_task *task);
119 	void		(*set_retrans_timeout)(struct rpc_task *task);
120 	void		(*timer)(struct rpc_task *task);
121 	void		(*release_request)(struct rpc_task *task);
122 	void		(*close)(struct rpc_xprt *xprt);
123 	void		(*destroy)(struct rpc_xprt *xprt);
124 	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
125 };
126 
127 /*
128  * RPC transport identifiers
129  *
130  * To preserve compatibility with the historical use of raw IP protocol
131  * id's for transport selection, UDP and TCP identifiers are specified
132  * with the previous values. No such restriction exists for new transports,
133  * except that they may not collide with these values (17 and 6,
134  * respectively).
135  */
136 #define XPRT_TRANSPORT_BC       (1 << 31)
137 enum xprt_transports {
138 	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
139 	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
140 	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,
141 	XPRT_TRANSPORT_RDMA	= 256
142 };
143 
144 struct rpc_xprt {
145 	struct kref		kref;		/* Reference count */
146 	struct rpc_xprt_ops *	ops;		/* transport methods */
147 
148 	const struct rpc_timeout *timeout;	/* timeout parms */
149 	struct sockaddr_storage	addr;		/* server address */
150 	size_t			addrlen;	/* size of server address */
151 	int			prot;		/* IP protocol */
152 
153 	unsigned long		cong;		/* current congestion */
154 	unsigned long		cwnd;		/* congestion window */
155 
156 	size_t			max_payload;	/* largest RPC payload size,
157 						   in bytes */
158 	unsigned int		tsh_size;	/* size of transport specific
159 						   header */
160 
161 	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */
162 	struct rpc_wait_queue	sending;	/* requests waiting to send */
163 	struct rpc_wait_queue	resend;		/* requests waiting to resend */
164 	struct rpc_wait_queue	pending;	/* requests in flight */
165 	struct rpc_wait_queue	backlog;	/* waiting for slot */
166 	struct list_head	free;		/* free slots */
167 	struct rpc_rqst *	slot;		/* slot table storage */
168 	unsigned int		max_reqs;	/* total slots */
169 	unsigned long		state;		/* transport state */
170 	unsigned char		shutdown   : 1,	/* being shut down */
171 				resvport   : 1; /* use a reserved port */
172 	unsigned int		bind_index;	/* bind function index */
173 
174 	/*
175 	 * Connection of transports
176 	 */
177 	unsigned long		connect_timeout,
178 				bind_timeout,
179 				reestablish_timeout;
180 	unsigned int		connect_cookie;	/* A cookie that gets bumped
181 						   every time the transport
182 						   is reconnected */
183 
184 	/*
185 	 * Disconnection of idle transports
186 	 */
187 	struct work_struct	task_cleanup;
188 	struct timer_list	timer;
189 	unsigned long		last_used,
190 				idle_timeout;
191 
192 	/*
193 	 * Send stuff
194 	 */
195 	spinlock_t		transport_lock;	/* lock transport info */
196 	spinlock_t		reserve_lock;	/* lock slot table */
197 	u32			xid;		/* Next XID value to use */
198 	struct rpc_task *	snd_task;	/* Task blocked in send */
199 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
200 #if defined(CONFIG_NFS_V4_1)
201 	struct svc_serv		*bc_serv;       /* The RPC service which will */
202 						/* process the callback */
203 	unsigned int		bc_alloc_count;	/* Total number of preallocs */
204 	spinlock_t		bc_pa_lock;	/* Protects the preallocated
205 						 * items */
206 	struct list_head	bc_pa_list;	/* List of preallocated
207 						 * backchannel rpc_rqst's */
208 #endif /* CONFIG_NFS_V4_1 */
209 	struct list_head	recv;
210 
211 	struct {
212 		unsigned long		bind_count,	/* total number of binds */
213 					connect_count,	/* total number of connects */
214 					connect_start,	/* connect start timestamp */
215 					connect_time,	/* jiffies waiting for connect */
216 					sends,		/* how many complete requests */
217 					recvs,		/* how many complete requests */
218 					bad_xids;	/* lookup_rqst didn't find XID */
219 
220 		unsigned long long	req_u,		/* average requests on the wire */
221 					bklog_u;	/* backlog queue utilization */
222 	} stat;
223 
224 	const char		*address_strings[RPC_DISPLAY_MAX];
225 };
226 
227 #if defined(CONFIG_NFS_V4_1)
228 /*
229  * Backchannel flags
230  */
231 #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
232 						/* buffer in use */
233 #endif /* CONFIG_NFS_V4_1 */
234 
235 #if defined(CONFIG_NFS_V4_1)
236 static inline int bc_prealloc(struct rpc_rqst *req)
237 {
238 	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
239 }
240 #else
241 static inline int bc_prealloc(struct rpc_rqst *req)
242 {
243 	return 0;
244 }
245 #endif /* CONFIG_NFS_V4_1 */
246 
247 struct xprt_create {
248 	int			ident;		/* XPRT_TRANSPORT identifier */
249 	struct sockaddr *	srcaddr;	/* optional local address */
250 	struct sockaddr *	dstaddr;	/* remote peer address */
251 	size_t			addrlen;
252 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
253 };
254 
255 struct xprt_class {
256 	struct list_head	list;
257 	int			ident;		/* XPRT_TRANSPORT identifier */
258 	struct rpc_xprt *	(*setup)(struct xprt_create *);
259 	struct module		*owner;
260 	char			name[32];
261 };
262 
263 /*
264  * Generic internal transport functions
265  */
266 struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
267 void			xprt_connect(struct rpc_task *task);
268 void			xprt_reserve(struct rpc_task *task);
269 int			xprt_reserve_xprt(struct rpc_task *task);
270 int			xprt_reserve_xprt_cong(struct rpc_task *task);
271 int			xprt_prepare_transmit(struct rpc_task *task);
272 void			xprt_transmit(struct rpc_task *task);
273 void			xprt_end_transmit(struct rpc_task *task);
274 int			xprt_adjust_timeout(struct rpc_rqst *req);
275 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
276 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
277 void			xprt_release(struct rpc_task *task);
278 struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
279 void			xprt_put(struct rpc_xprt *xprt);
280 
281 static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p)
282 {
283 	return p + xprt->tsh_size;
284 }
285 
286 /*
287  * Transport switch helper functions
288  */
289 int			xprt_register_transport(struct xprt_class *type);
290 int			xprt_unregister_transport(struct xprt_class *type);
291 int			xprt_load_transport(const char *);
292 void			xprt_set_retrans_timeout_def(struct rpc_task *task);
293 void			xprt_set_retrans_timeout_rtt(struct rpc_task *task);
294 void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
295 void			xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action);
296 void			xprt_write_space(struct rpc_xprt *xprt);
297 void			xprt_update_rtt(struct rpc_task *task);
298 void			xprt_adjust_cwnd(struct rpc_task *task, int result);
299 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
300 void			xprt_complete_rqst(struct rpc_task *task, int copied);
301 void			xprt_release_rqst_cong(struct rpc_task *task);
302 void			xprt_disconnect_done(struct rpc_xprt *xprt);
303 void			xprt_force_disconnect(struct rpc_xprt *xprt);
304 void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
305 
306 /*
307  * Reserved bit positions in xprt->state
308  */
309 #define XPRT_LOCKED		(0)
310 #define XPRT_CONNECTED		(1)
311 #define XPRT_CONNECTING		(2)
312 #define XPRT_CLOSE_WAIT		(3)
313 #define XPRT_BOUND		(4)
314 #define XPRT_BINDING		(5)
315 #define XPRT_CLOSING		(6)
316 #define XPRT_CONNECTION_ABORT	(7)
317 #define XPRT_CONNECTION_CLOSE	(8)
318 
319 static inline void xprt_set_connected(struct rpc_xprt *xprt)
320 {
321 	set_bit(XPRT_CONNECTED, &xprt->state);
322 }
323 
324 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
325 {
326 	clear_bit(XPRT_CONNECTED, &xprt->state);
327 }
328 
329 static inline int xprt_connected(struct rpc_xprt *xprt)
330 {
331 	return test_bit(XPRT_CONNECTED, &xprt->state);
332 }
333 
334 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
335 {
336 	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
337 }
338 
339 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
340 {
341 	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
342 }
343 
344 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
345 {
346 	smp_mb__before_clear_bit();
347 	clear_bit(XPRT_CONNECTING, &xprt->state);
348 	smp_mb__after_clear_bit();
349 }
350 
351 static inline int xprt_connecting(struct rpc_xprt *xprt)
352 {
353 	return test_bit(XPRT_CONNECTING, &xprt->state);
354 }
355 
356 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
357 {
358 	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
359 }
360 
361 static inline void xprt_set_bound(struct rpc_xprt *xprt)
362 {
363 	test_and_set_bit(XPRT_BOUND, &xprt->state);
364 }
365 
366 static inline int xprt_bound(struct rpc_xprt *xprt)
367 {
368 	return test_bit(XPRT_BOUND, &xprt->state);
369 }
370 
371 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
372 {
373 	clear_bit(XPRT_BOUND, &xprt->state);
374 }
375 
376 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
377 {
378 	smp_mb__before_clear_bit();
379 	clear_bit(XPRT_BINDING, &xprt->state);
380 	smp_mb__after_clear_bit();
381 }
382 
383 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
384 {
385 	return test_and_set_bit(XPRT_BINDING, &xprt->state);
386 }
387 
388 #endif /* __KERNEL__*/
389 
390 #endif /* _LINUX_SUNRPC_XPRT_H */
391