1/*
2 *  linux/include/linux/sunrpc/clnt_xprt.h
3 *
4 *  Declarations for the RPC transport interface.
5 *
6 *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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/sunrpc/sched.h>
16#include <linux/sunrpc/xdr.h>
17
18/*
19 * The transport code maintains an estimate on the maximum number of out-
20 * standing RPC requests, using a smoothed version of the congestion
21 * avoidance implemented in 44BSD. This is basically the Van Jacobson
22 * congestion algorithm: If a retransmit occurs, the congestion window is
23 * halved; otherwise, it is incremented by 1/cwnd when
24 *
25 *	-	a reply is received and
26 *	-	a full number of requests are outstanding and
27 *	-	the congestion window hasn't been updated recently.
28 *
29 * Upper procedures may check whether a request would block waiting for
30 * a free RPC slot by using the RPC_CONGESTED() macro.
31 *
32 * Note: on machines with low memory we should probably use a smaller
33 * MAXREQS value: At 32 outstanding reqs with 8 megs of RAM, fragment
34 * reassembly will frequently run out of memory.
35 */
36#define RPC_MAXCONG		(16)
37#define RPC_MAXREQS		RPC_MAXCONG
38#define RPC_CWNDSCALE		(256)
39#define RPC_MAXCWND		(RPC_MAXCONG * RPC_CWNDSCALE)
40#define RPC_INITCWND		RPC_CWNDSCALE
41#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
42
43/* Default timeout values */
44#define RPC_MAX_UDP_TIMEOUT	(60*HZ)
45#define RPC_MAX_TCP_TIMEOUT	(600*HZ)
46
47/* RPC call and reply header size as number of 32bit words (verifier
48 * size computed separately)
49 */
50#define RPC_CALLHDRSIZE		6
51#define RPC_REPHDRSIZE		4
52
53/*
54 * This describes a timeout strategy
55 */
56struct rpc_timeout {
57	unsigned long		to_current,		/* current timeout */
58				to_initval,		/* initial timeout */
59				to_maxval,		/* max timeout */
60				to_increment,		/* if !exponential */
61				to_resrvval;		/* reserve timeout */
62	short			to_retries;		/* max # of retries */
63	unsigned char		to_exponential;
64};
65
66/*
67 * This describes a complete RPC request
68 */
69struct rpc_rqst {
70	/*
71	 * This is the user-visible part
72	 */
73	struct rpc_xprt *	rq_xprt;		/* RPC client */
74	struct rpc_timeout	rq_timeout;		/* timeout parms */
75	struct xdr_buf		rq_snd_buf;		/* send buffer */
76	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
77
78	/*
79	 * This is the private part
80	 */
81	struct rpc_task *	rq_task;	/* RPC task data */
82	__u32			rq_xid;		/* request XID */
83	struct rpc_rqst *	rq_next;	/* free list */
84	int			rq_cong;	/* has incremented xprt->cong */
85	int			rq_received;	/* receive completed */
86
87	struct list_head	rq_list;
88
89	/*
90	 * For authentication (e.g. auth_des)
91	 */
92	u32			rq_creddata[2];
93
94	/*
95	 * Partial send handling
96	 */
97
98	u32			rq_bytes_sent;	/* Bytes we have sent */
99
100	long			rq_xtime;	/* when transmitted */
101	int			rq_ntimeo;
102	int			rq_nresend;
103};
104#define rq_svec			rq_snd_buf.head
105#define rq_slen			rq_snd_buf.len
106#define rq_rvec			rq_rcv_buf.head
107#define rq_rlen			rq_rcv_buf.len
108
109#define XPRT_LAST_FRAG		(1 << 0)
110#define XPRT_COPY_RECM		(1 << 1)
111#define XPRT_COPY_XID		(1 << 2)
112#define XPRT_COPY_DATA		(1 << 3)
113
114struct rpc_xprt {
115	struct socket *		sock;		/* BSD socket layer */
116	struct sock *		inet;		/* INET layer */
117
118	struct rpc_timeout	timeout;	/* timeout parms */
119	struct sockaddr_in	addr;		/* server address */
120	int			prot;		/* IP protocol */
121
122	unsigned long		cong;		/* current congestion */
123	unsigned long		cwnd;		/* congestion window */
124
125	unsigned int		rcvsize,	/* socket receive buffer size */
126				sndsize;	/* socket send buffer size */
127
128	struct rpc_wait_queue	sending;	/* requests waiting to send */
129	struct rpc_wait_queue	resend;		/* requests waiting to resend */
130	struct rpc_wait_queue	pending;	/* requests in flight */
131	struct rpc_wait_queue	backlog;	/* waiting for slot */
132	struct rpc_rqst *	free;		/* free slots */
133	struct rpc_rqst		slot[RPC_MAXREQS];
134	unsigned long		sockstate;	/* Socket state */
135	unsigned char		shutdown   : 1,	/* being shut down */
136				nocong	   : 1,	/* no congestion control */
137				stream     : 1;	/* TCP */
138
139	/*
140	 * State of TCP reply receive stuff
141	 */
142	u32			tcp_recm,	/* Fragment header */
143				tcp_xid,	/* Current XID */
144				tcp_reclen,	/* fragment length */
145				tcp_offset;	/* fragment offset */
146	unsigned long		tcp_copied,	/* copied to request */
147				tcp_flags;
148
149	/*
150	 * Send stuff
151	 */
152	spinlock_t		sock_lock;	/* lock socket info */
153	spinlock_t		xprt_lock;	/* lock xprt info */
154	struct rpc_task *	snd_task;	/* Task blocked in send */
155
156	struct list_head	recv;
157
158
159	void			(*old_data_ready)(struct sock *, int);
160	void			(*old_state_change)(struct sock *);
161	void			(*old_write_space)(struct sock *);
162
163	wait_queue_head_t	cong_wait;
164};
165
166#ifdef __KERNEL__
167
168struct rpc_xprt *	xprt_create_proto(int proto, struct sockaddr_in *addr,
169					struct rpc_timeout *toparms);
170int			xprt_destroy(struct rpc_xprt *);
171void			xprt_shutdown(struct rpc_xprt *);
172void			xprt_default_timeout(struct rpc_timeout *, int);
173void			xprt_set_timeout(struct rpc_timeout *, unsigned int,
174					unsigned long);
175
176int			xprt_reserve(struct rpc_task *);
177void			xprt_transmit(struct rpc_task *);
178void			xprt_receive(struct rpc_task *);
179int			xprt_adjust_timeout(struct rpc_timeout *);
180void			xprt_release(struct rpc_task *);
181void			xprt_reconnect(struct rpc_task *);
182int			xprt_clear_backlog(struct rpc_xprt *);
183void			xprt_sock_setbufsize(struct rpc_xprt *);
184
185#define XPRT_CONNECT	0
186
187#define xprt_connected(xp)		(!(xp)->stream || test_bit(XPRT_CONNECT, &(xp)->sockstate))
188#define xprt_set_connected(xp)		(set_bit(XPRT_CONNECT, &(xp)->sockstate))
189#define xprt_test_and_set_connected(xp)	(test_and_set_bit(XPRT_CONNECT, &(xp)->sockstate))
190#define xprt_clear_connected(xp)	(clear_bit(XPRT_CONNECT, &(xp)->sockstate))
191
192#endif /* __KERNEL__*/
193
194#endif /* _LINUX_SUNRPC_XPRT_H */
195