xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision b04b4f78)
1 /*
2  * linux/net/sunrpc/xprtsock.c
3  *
4  * Client-side transport implementation for sockets.
5  *
6  * TCP callback races fixes (C) 1998 Red Hat
7  * TCP send fixes (C) 1998 Red Hat
8  * TCP NFS related read + write fixes
9  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
10  *
11  * Rewrite of larges part of the code in order to stabilize TCP stuff.
12  * Fix behaviour when socket buffer is full.
13  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
14  *
15  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
16  *
17  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
18  *   <gilles.quillard@bull.net>
19  */
20 
21 #include <linux/types.h>
22 #include <linux/slab.h>
23 #include <linux/module.h>
24 #include <linux/capability.h>
25 #include <linux/pagemap.h>
26 #include <linux/errno.h>
27 #include <linux/socket.h>
28 #include <linux/in.h>
29 #include <linux/net.h>
30 #include <linux/mm.h>
31 #include <linux/udp.h>
32 #include <linux/tcp.h>
33 #include <linux/sunrpc/clnt.h>
34 #include <linux/sunrpc/sched.h>
35 #include <linux/sunrpc/xprtsock.h>
36 #include <linux/file.h>
37 
38 #include <net/sock.h>
39 #include <net/checksum.h>
40 #include <net/udp.h>
41 #include <net/tcp.h>
42 
43 /*
44  * xprtsock tunables
45  */
46 unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
47 unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
48 
49 unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
50 unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
51 
52 #define XS_TCP_LINGER_TO	(15U * HZ)
53 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
54 
55 /*
56  * We can register our own files under /proc/sys/sunrpc by
57  * calling register_sysctl_table() again.  The files in that
58  * directory become the union of all files registered there.
59  *
60  * We simply need to make sure that we don't collide with
61  * someone else's file names!
62  */
63 
64 #ifdef RPC_DEBUG
65 
66 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
67 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
68 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
69 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
70 
71 static struct ctl_table_header *sunrpc_table_header;
72 
73 /*
74  * FIXME: changing the UDP slot table size should also resize the UDP
75  *        socket buffers for existing UDP transports
76  */
77 static ctl_table xs_tunables_table[] = {
78 	{
79 		.ctl_name	= CTL_SLOTTABLE_UDP,
80 		.procname	= "udp_slot_table_entries",
81 		.data		= &xprt_udp_slot_table_entries,
82 		.maxlen		= sizeof(unsigned int),
83 		.mode		= 0644,
84 		.proc_handler	= &proc_dointvec_minmax,
85 		.strategy	= &sysctl_intvec,
86 		.extra1		= &min_slot_table_size,
87 		.extra2		= &max_slot_table_size
88 	},
89 	{
90 		.ctl_name	= CTL_SLOTTABLE_TCP,
91 		.procname	= "tcp_slot_table_entries",
92 		.data		= &xprt_tcp_slot_table_entries,
93 		.maxlen		= sizeof(unsigned int),
94 		.mode		= 0644,
95 		.proc_handler	= &proc_dointvec_minmax,
96 		.strategy	= &sysctl_intvec,
97 		.extra1		= &min_slot_table_size,
98 		.extra2		= &max_slot_table_size
99 	},
100 	{
101 		.ctl_name	= CTL_MIN_RESVPORT,
102 		.procname	= "min_resvport",
103 		.data		= &xprt_min_resvport,
104 		.maxlen		= sizeof(unsigned int),
105 		.mode		= 0644,
106 		.proc_handler	= &proc_dointvec_minmax,
107 		.strategy	= &sysctl_intvec,
108 		.extra1		= &xprt_min_resvport_limit,
109 		.extra2		= &xprt_max_resvport_limit
110 	},
111 	{
112 		.ctl_name	= CTL_MAX_RESVPORT,
113 		.procname	= "max_resvport",
114 		.data		= &xprt_max_resvport,
115 		.maxlen		= sizeof(unsigned int),
116 		.mode		= 0644,
117 		.proc_handler	= &proc_dointvec_minmax,
118 		.strategy	= &sysctl_intvec,
119 		.extra1		= &xprt_min_resvport_limit,
120 		.extra2		= &xprt_max_resvport_limit
121 	},
122 	{
123 		.procname	= "tcp_fin_timeout",
124 		.data		= &xs_tcp_fin_timeout,
125 		.maxlen		= sizeof(xs_tcp_fin_timeout),
126 		.mode		= 0644,
127 		.proc_handler	= &proc_dointvec_jiffies,
128 		.strategy	= sysctl_jiffies
129 	},
130 	{
131 		.ctl_name = 0,
132 	},
133 };
134 
135 static ctl_table sunrpc_table[] = {
136 	{
137 		.ctl_name	= CTL_SUNRPC,
138 		.procname	= "sunrpc",
139 		.mode		= 0555,
140 		.child		= xs_tunables_table
141 	},
142 	{
143 		.ctl_name = 0,
144 	},
145 };
146 
147 #endif
148 
149 /*
150  * Time out for an RPC UDP socket connect.  UDP socket connects are
151  * synchronous, but we set a timeout anyway in case of resource
152  * exhaustion on the local host.
153  */
154 #define XS_UDP_CONN_TO		(5U * HZ)
155 
156 /*
157  * Wait duration for an RPC TCP connection to be established.  Solaris
158  * NFS over TCP uses 60 seconds, for example, which is in line with how
159  * long a server takes to reboot.
160  */
161 #define XS_TCP_CONN_TO		(60U * HZ)
162 
163 /*
164  * Wait duration for a reply from the RPC portmapper.
165  */
166 #define XS_BIND_TO		(60U * HZ)
167 
168 /*
169  * Delay if a UDP socket connect error occurs.  This is most likely some
170  * kind of resource problem on the local host.
171  */
172 #define XS_UDP_REEST_TO		(2U * HZ)
173 
174 /*
175  * The reestablish timeout allows clients to delay for a bit before attempting
176  * to reconnect to a server that just dropped our connection.
177  *
178  * We implement an exponential backoff when trying to reestablish a TCP
179  * transport connection with the server.  Some servers like to drop a TCP
180  * connection when they are overworked, so we start with a short timeout and
181  * increase over time if the server is down or not responding.
182  */
183 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
184 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
185 
186 /*
187  * TCP idle timeout; client drops the transport socket if it is idle
188  * for this long.  Note that we also timeout UDP sockets to prevent
189  * holding port numbers when there is no RPC traffic.
190  */
191 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
192 
193 #ifdef RPC_DEBUG
194 # undef  RPC_DEBUG_DATA
195 # define RPCDBG_FACILITY	RPCDBG_TRANS
196 #endif
197 
198 #ifdef RPC_DEBUG_DATA
199 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
200 {
201 	u8 *buf = (u8 *) packet;
202 	int j;
203 
204 	dprintk("RPC:       %s\n", msg);
205 	for (j = 0; j < count && j < 128; j += 4) {
206 		if (!(j & 31)) {
207 			if (j)
208 				dprintk("\n");
209 			dprintk("0x%04x ", j);
210 		}
211 		dprintk("%02x%02x%02x%02x ",
212 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
213 	}
214 	dprintk("\n");
215 }
216 #else
217 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
218 {
219 	/* NOP */
220 }
221 #endif
222 
223 struct sock_xprt {
224 	struct rpc_xprt		xprt;
225 
226 	/*
227 	 * Network layer
228 	 */
229 	struct socket *		sock;
230 	struct sock *		inet;
231 
232 	/*
233 	 * State of TCP reply receive
234 	 */
235 	__be32			tcp_fraghdr,
236 				tcp_xid;
237 
238 	u32			tcp_offset,
239 				tcp_reclen;
240 
241 	unsigned long		tcp_copied,
242 				tcp_flags;
243 
244 	/*
245 	 * Connection of transports
246 	 */
247 	struct delayed_work	connect_worker;
248 	struct sockaddr_storage	addr;
249 	unsigned short		port;
250 
251 	/*
252 	 * UDP socket buffer size parameters
253 	 */
254 	size_t			rcvsize,
255 				sndsize;
256 
257 	/*
258 	 * Saved socket callback addresses
259 	 */
260 	void			(*old_data_ready)(struct sock *, int);
261 	void			(*old_state_change)(struct sock *);
262 	void			(*old_write_space)(struct sock *);
263 	void			(*old_error_report)(struct sock *);
264 };
265 
266 /*
267  * TCP receive state flags
268  */
269 #define TCP_RCV_LAST_FRAG	(1UL << 0)
270 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
271 #define TCP_RCV_COPY_XID	(1UL << 2)
272 #define TCP_RCV_COPY_DATA	(1UL << 3)
273 
274 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
275 {
276 	return (struct sockaddr *) &xprt->addr;
277 }
278 
279 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
280 {
281 	return (struct sockaddr_in *) &xprt->addr;
282 }
283 
284 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
285 {
286 	return (struct sockaddr_in6 *) &xprt->addr;
287 }
288 
289 static void xs_format_ipv4_peer_addresses(struct rpc_xprt *xprt,
290 					  const char *protocol,
291 					  const char *netid)
292 {
293 	struct sockaddr_in *addr = xs_addr_in(xprt);
294 	char *buf;
295 
296 	buf = kzalloc(20, GFP_KERNEL);
297 	if (buf) {
298 		snprintf(buf, 20, "%pI4", &addr->sin_addr.s_addr);
299 	}
300 	xprt->address_strings[RPC_DISPLAY_ADDR] = buf;
301 
302 	buf = kzalloc(8, GFP_KERNEL);
303 	if (buf) {
304 		snprintf(buf, 8, "%u",
305 				ntohs(addr->sin_port));
306 	}
307 	xprt->address_strings[RPC_DISPLAY_PORT] = buf;
308 
309 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
310 
311 	buf = kzalloc(48, GFP_KERNEL);
312 	if (buf) {
313 		snprintf(buf, 48, "addr=%pI4 port=%u proto=%s",
314 			&addr->sin_addr.s_addr,
315 			ntohs(addr->sin_port),
316 			protocol);
317 	}
318 	xprt->address_strings[RPC_DISPLAY_ALL] = buf;
319 
320 	buf = kzalloc(10, GFP_KERNEL);
321 	if (buf) {
322 		snprintf(buf, 10, "%02x%02x%02x%02x",
323 				NIPQUAD(addr->sin_addr.s_addr));
324 	}
325 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = buf;
326 
327 	buf = kzalloc(8, GFP_KERNEL);
328 	if (buf) {
329 		snprintf(buf, 8, "%4hx",
330 				ntohs(addr->sin_port));
331 	}
332 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = buf;
333 
334 	buf = kzalloc(30, GFP_KERNEL);
335 	if (buf) {
336 		snprintf(buf, 30, "%pI4.%u.%u",
337 				&addr->sin_addr.s_addr,
338 				ntohs(addr->sin_port) >> 8,
339 				ntohs(addr->sin_port) & 0xff);
340 	}
341 	xprt->address_strings[RPC_DISPLAY_UNIVERSAL_ADDR] = buf;
342 
343 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
344 }
345 
346 static void xs_format_ipv6_peer_addresses(struct rpc_xprt *xprt,
347 					  const char *protocol,
348 					  const char *netid)
349 {
350 	struct sockaddr_in6 *addr = xs_addr_in6(xprt);
351 	char *buf;
352 
353 	buf = kzalloc(40, GFP_KERNEL);
354 	if (buf) {
355 		snprintf(buf, 40, "%pI6",&addr->sin6_addr);
356 	}
357 	xprt->address_strings[RPC_DISPLAY_ADDR] = buf;
358 
359 	buf = kzalloc(8, GFP_KERNEL);
360 	if (buf) {
361 		snprintf(buf, 8, "%u",
362 				ntohs(addr->sin6_port));
363 	}
364 	xprt->address_strings[RPC_DISPLAY_PORT] = buf;
365 
366 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
367 
368 	buf = kzalloc(64, GFP_KERNEL);
369 	if (buf) {
370 		snprintf(buf, 64, "addr=%pI6 port=%u proto=%s",
371 				&addr->sin6_addr,
372 				ntohs(addr->sin6_port),
373 				protocol);
374 	}
375 	xprt->address_strings[RPC_DISPLAY_ALL] = buf;
376 
377 	buf = kzalloc(36, GFP_KERNEL);
378 	if (buf)
379 		snprintf(buf, 36, "%pi6", &addr->sin6_addr);
380 
381 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = buf;
382 
383 	buf = kzalloc(8, GFP_KERNEL);
384 	if (buf) {
385 		snprintf(buf, 8, "%4hx",
386 				ntohs(addr->sin6_port));
387 	}
388 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = buf;
389 
390 	buf = kzalloc(50, GFP_KERNEL);
391 	if (buf) {
392 		snprintf(buf, 50, "%pI6.%u.%u",
393 			 &addr->sin6_addr,
394 			 ntohs(addr->sin6_port) >> 8,
395 			 ntohs(addr->sin6_port) & 0xff);
396 	}
397 	xprt->address_strings[RPC_DISPLAY_UNIVERSAL_ADDR] = buf;
398 
399 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
400 }
401 
402 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
403 {
404 	unsigned int i;
405 
406 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
407 		switch (i) {
408 		case RPC_DISPLAY_PROTO:
409 		case RPC_DISPLAY_NETID:
410 			continue;
411 		default:
412 			kfree(xprt->address_strings[i]);
413 		}
414 }
415 
416 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
417 
418 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
419 {
420 	struct msghdr msg = {
421 		.msg_name	= addr,
422 		.msg_namelen	= addrlen,
423 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
424 	};
425 	struct kvec iov = {
426 		.iov_base	= vec->iov_base + base,
427 		.iov_len	= vec->iov_len - base,
428 	};
429 
430 	if (iov.iov_len != 0)
431 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
432 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
433 }
434 
435 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
436 {
437 	struct page **ppage;
438 	unsigned int remainder;
439 	int err, sent = 0;
440 
441 	remainder = xdr->page_len - base;
442 	base += xdr->page_base;
443 	ppage = xdr->pages + (base >> PAGE_SHIFT);
444 	base &= ~PAGE_MASK;
445 	for(;;) {
446 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
447 		int flags = XS_SENDMSG_FLAGS;
448 
449 		remainder -= len;
450 		if (remainder != 0 || more)
451 			flags |= MSG_MORE;
452 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
453 		if (remainder == 0 || err != len)
454 			break;
455 		sent += err;
456 		ppage++;
457 		base = 0;
458 	}
459 	if (sent == 0)
460 		return err;
461 	if (err > 0)
462 		sent += err;
463 	return sent;
464 }
465 
466 /**
467  * xs_sendpages - write pages directly to a socket
468  * @sock: socket to send on
469  * @addr: UDP only -- address of destination
470  * @addrlen: UDP only -- length of destination address
471  * @xdr: buffer containing this request
472  * @base: starting position in the buffer
473  *
474  */
475 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
476 {
477 	unsigned int remainder = xdr->len - base;
478 	int err, sent = 0;
479 
480 	if (unlikely(!sock))
481 		return -ENOTSOCK;
482 
483 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
484 	if (base != 0) {
485 		addr = NULL;
486 		addrlen = 0;
487 	}
488 
489 	if (base < xdr->head[0].iov_len || addr != NULL) {
490 		unsigned int len = xdr->head[0].iov_len - base;
491 		remainder -= len;
492 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
493 		if (remainder == 0 || err != len)
494 			goto out;
495 		sent += err;
496 		base = 0;
497 	} else
498 		base -= xdr->head[0].iov_len;
499 
500 	if (base < xdr->page_len) {
501 		unsigned int len = xdr->page_len - base;
502 		remainder -= len;
503 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
504 		if (remainder == 0 || err != len)
505 			goto out;
506 		sent += err;
507 		base = 0;
508 	} else
509 		base -= xdr->page_len;
510 
511 	if (base >= xdr->tail[0].iov_len)
512 		return sent;
513 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
514 out:
515 	if (sent == 0)
516 		return err;
517 	if (err > 0)
518 		sent += err;
519 	return sent;
520 }
521 
522 static void xs_nospace_callback(struct rpc_task *task)
523 {
524 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
525 
526 	transport->inet->sk_write_pending--;
527 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
528 }
529 
530 /**
531  * xs_nospace - place task on wait queue if transmit was incomplete
532  * @task: task to put to sleep
533  *
534  */
535 static int xs_nospace(struct rpc_task *task)
536 {
537 	struct rpc_rqst *req = task->tk_rqstp;
538 	struct rpc_xprt *xprt = req->rq_xprt;
539 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
540 	int ret = 0;
541 
542 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
543 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
544 			req->rq_slen);
545 
546 	/* Protect against races with write_space */
547 	spin_lock_bh(&xprt->transport_lock);
548 
549 	/* Don't race with disconnect */
550 	if (xprt_connected(xprt)) {
551 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
552 			ret = -EAGAIN;
553 			/*
554 			 * Notify TCP that we're limited by the application
555 			 * window size
556 			 */
557 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
558 			transport->inet->sk_write_pending++;
559 			/* ...and wait for more buffer space */
560 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
561 		}
562 	} else {
563 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
564 		ret = -ENOTCONN;
565 	}
566 
567 	spin_unlock_bh(&xprt->transport_lock);
568 	return ret;
569 }
570 
571 /**
572  * xs_udp_send_request - write an RPC request to a UDP socket
573  * @task: address of RPC task that manages the state of an RPC request
574  *
575  * Return values:
576  *        0:	The request has been sent
577  *   EAGAIN:	The socket was blocked, please call again later to
578  *		complete the request
579  * ENOTCONN:	Caller needs to invoke connect logic then call again
580  *    other:	Some other error occured, the request was not sent
581  */
582 static int xs_udp_send_request(struct rpc_task *task)
583 {
584 	struct rpc_rqst *req = task->tk_rqstp;
585 	struct rpc_xprt *xprt = req->rq_xprt;
586 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
587 	struct xdr_buf *xdr = &req->rq_snd_buf;
588 	int status;
589 
590 	xs_pktdump("packet data:",
591 				req->rq_svec->iov_base,
592 				req->rq_svec->iov_len);
593 
594 	if (!xprt_bound(xprt))
595 		return -ENOTCONN;
596 	status = xs_sendpages(transport->sock,
597 			      xs_addr(xprt),
598 			      xprt->addrlen, xdr,
599 			      req->rq_bytes_sent);
600 
601 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
602 			xdr->len - req->rq_bytes_sent, status);
603 
604 	if (status >= 0) {
605 		task->tk_bytes_sent += status;
606 		if (status >= req->rq_slen)
607 			return 0;
608 		/* Still some bytes left; set up for a retry later. */
609 		status = -EAGAIN;
610 	}
611 	if (!transport->sock)
612 		goto out;
613 
614 	switch (status) {
615 	case -ENOTSOCK:
616 		status = -ENOTCONN;
617 		/* Should we call xs_close() here? */
618 		break;
619 	case -EAGAIN:
620 		status = xs_nospace(task);
621 		break;
622 	default:
623 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
624 			-status);
625 	case -ENETUNREACH:
626 	case -EPIPE:
627 	case -ECONNREFUSED:
628 		/* When the server has died, an ICMP port unreachable message
629 		 * prompts ECONNREFUSED. */
630 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
631 	}
632 out:
633 	return status;
634 }
635 
636 /**
637  * xs_tcp_shutdown - gracefully shut down a TCP socket
638  * @xprt: transport
639  *
640  * Initiates a graceful shutdown of the TCP socket by calling the
641  * equivalent of shutdown(SHUT_WR);
642  */
643 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
644 {
645 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
646 	struct socket *sock = transport->sock;
647 
648 	if (sock != NULL)
649 		kernel_sock_shutdown(sock, SHUT_WR);
650 }
651 
652 static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
653 {
654 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
655 	rpc_fraghdr *base = buf->head[0].iov_base;
656 	*base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
657 }
658 
659 /**
660  * xs_tcp_send_request - write an RPC request to a TCP socket
661  * @task: address of RPC task that manages the state of an RPC request
662  *
663  * Return values:
664  *        0:	The request has been sent
665  *   EAGAIN:	The socket was blocked, please call again later to
666  *		complete the request
667  * ENOTCONN:	Caller needs to invoke connect logic then call again
668  *    other:	Some other error occured, the request was not sent
669  *
670  * XXX: In the case of soft timeouts, should we eventually give up
671  *	if sendmsg is not able to make progress?
672  */
673 static int xs_tcp_send_request(struct rpc_task *task)
674 {
675 	struct rpc_rqst *req = task->tk_rqstp;
676 	struct rpc_xprt *xprt = req->rq_xprt;
677 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
678 	struct xdr_buf *xdr = &req->rq_snd_buf;
679 	int status;
680 
681 	xs_encode_tcp_record_marker(&req->rq_snd_buf);
682 
683 	xs_pktdump("packet data:",
684 				req->rq_svec->iov_base,
685 				req->rq_svec->iov_len);
686 
687 	/* Continue transmitting the packet/record. We must be careful
688 	 * to cope with writespace callbacks arriving _after_ we have
689 	 * called sendmsg(). */
690 	while (1) {
691 		status = xs_sendpages(transport->sock,
692 					NULL, 0, xdr, req->rq_bytes_sent);
693 
694 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
695 				xdr->len - req->rq_bytes_sent, status);
696 
697 		if (unlikely(status < 0))
698 			break;
699 
700 		/* If we've sent the entire packet, immediately
701 		 * reset the count of bytes sent. */
702 		req->rq_bytes_sent += status;
703 		task->tk_bytes_sent += status;
704 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
705 			req->rq_bytes_sent = 0;
706 			return 0;
707 		}
708 
709 		if (status != 0)
710 			continue;
711 		status = -EAGAIN;
712 		break;
713 	}
714 	if (!transport->sock)
715 		goto out;
716 
717 	switch (status) {
718 	case -ENOTSOCK:
719 		status = -ENOTCONN;
720 		/* Should we call xs_close() here? */
721 		break;
722 	case -EAGAIN:
723 		status = xs_nospace(task);
724 		break;
725 	default:
726 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
727 			-status);
728 	case -ECONNRESET:
729 	case -EPIPE:
730 		xs_tcp_shutdown(xprt);
731 	case -ECONNREFUSED:
732 	case -ENOTCONN:
733 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
734 	}
735 out:
736 	return status;
737 }
738 
739 /**
740  * xs_tcp_release_xprt - clean up after a tcp transmission
741  * @xprt: transport
742  * @task: rpc task
743  *
744  * This cleans up if an error causes us to abort the transmission of a request.
745  * In this case, the socket may need to be reset in order to avoid confusing
746  * the server.
747  */
748 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
749 {
750 	struct rpc_rqst *req;
751 
752 	if (task != xprt->snd_task)
753 		return;
754 	if (task == NULL)
755 		goto out_release;
756 	req = task->tk_rqstp;
757 	if (req->rq_bytes_sent == 0)
758 		goto out_release;
759 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
760 		goto out_release;
761 	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
762 out_release:
763 	xprt_release_xprt(xprt, task);
764 }
765 
766 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
767 {
768 	transport->old_data_ready = sk->sk_data_ready;
769 	transport->old_state_change = sk->sk_state_change;
770 	transport->old_write_space = sk->sk_write_space;
771 	transport->old_error_report = sk->sk_error_report;
772 }
773 
774 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
775 {
776 	sk->sk_data_ready = transport->old_data_ready;
777 	sk->sk_state_change = transport->old_state_change;
778 	sk->sk_write_space = transport->old_write_space;
779 	sk->sk_error_report = transport->old_error_report;
780 }
781 
782 static void xs_reset_transport(struct sock_xprt *transport)
783 {
784 	struct socket *sock = transport->sock;
785 	struct sock *sk = transport->inet;
786 
787 	if (sk == NULL)
788 		return;
789 
790 	write_lock_bh(&sk->sk_callback_lock);
791 	transport->inet = NULL;
792 	transport->sock = NULL;
793 
794 	sk->sk_user_data = NULL;
795 
796 	xs_restore_old_callbacks(transport, sk);
797 	write_unlock_bh(&sk->sk_callback_lock);
798 
799 	sk->sk_no_check = 0;
800 
801 	sock_release(sock);
802 }
803 
804 /**
805  * xs_close - close a socket
806  * @xprt: transport
807  *
808  * This is used when all requests are complete; ie, no DRC state remains
809  * on the server we want to save.
810  *
811  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
812  * xs_reset_transport() zeroing the socket from underneath a writer.
813  */
814 static void xs_close(struct rpc_xprt *xprt)
815 {
816 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
817 
818 	dprintk("RPC:       xs_close xprt %p\n", xprt);
819 
820 	xs_reset_transport(transport);
821 
822 	smp_mb__before_clear_bit();
823 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
824 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
825 	clear_bit(XPRT_CLOSING, &xprt->state);
826 	smp_mb__after_clear_bit();
827 	xprt_disconnect_done(xprt);
828 }
829 
830 static void xs_tcp_close(struct rpc_xprt *xprt)
831 {
832 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
833 		xs_close(xprt);
834 	else
835 		xs_tcp_shutdown(xprt);
836 }
837 
838 /**
839  * xs_destroy - prepare to shutdown a transport
840  * @xprt: doomed transport
841  *
842  */
843 static void xs_destroy(struct rpc_xprt *xprt)
844 {
845 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
846 
847 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
848 
849 	cancel_rearming_delayed_work(&transport->connect_worker);
850 
851 	xs_close(xprt);
852 	xs_free_peer_addresses(xprt);
853 	kfree(xprt->slot);
854 	kfree(xprt);
855 	module_put(THIS_MODULE);
856 }
857 
858 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
859 {
860 	return (struct rpc_xprt *) sk->sk_user_data;
861 }
862 
863 /**
864  * xs_udp_data_ready - "data ready" callback for UDP sockets
865  * @sk: socket with data to read
866  * @len: how much data to read
867  *
868  */
869 static void xs_udp_data_ready(struct sock *sk, int len)
870 {
871 	struct rpc_task *task;
872 	struct rpc_xprt *xprt;
873 	struct rpc_rqst *rovr;
874 	struct sk_buff *skb;
875 	int err, repsize, copied;
876 	u32 _xid;
877 	__be32 *xp;
878 
879 	read_lock(&sk->sk_callback_lock);
880 	dprintk("RPC:       xs_udp_data_ready...\n");
881 	if (!(xprt = xprt_from_sock(sk)))
882 		goto out;
883 
884 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
885 		goto out;
886 
887 	if (xprt->shutdown)
888 		goto dropit;
889 
890 	repsize = skb->len - sizeof(struct udphdr);
891 	if (repsize < 4) {
892 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
893 		goto dropit;
894 	}
895 
896 	/* Copy the XID from the skb... */
897 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
898 				sizeof(_xid), &_xid);
899 	if (xp == NULL)
900 		goto dropit;
901 
902 	/* Look up and lock the request corresponding to the given XID */
903 	spin_lock(&xprt->transport_lock);
904 	rovr = xprt_lookup_rqst(xprt, *xp);
905 	if (!rovr)
906 		goto out_unlock;
907 	task = rovr->rq_task;
908 
909 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
910 		copied = repsize;
911 
912 	/* Suck it into the iovec, verify checksum if not done by hw. */
913 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
914 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
915 		goto out_unlock;
916 	}
917 
918 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
919 
920 	/* Something worked... */
921 	dst_confirm(skb->dst);
922 
923 	xprt_adjust_cwnd(task, copied);
924 	xprt_update_rtt(task);
925 	xprt_complete_rqst(task, copied);
926 
927  out_unlock:
928 	spin_unlock(&xprt->transport_lock);
929  dropit:
930 	skb_free_datagram(sk, skb);
931  out:
932 	read_unlock(&sk->sk_callback_lock);
933 }
934 
935 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
936 {
937 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
938 	size_t len, used;
939 	char *p;
940 
941 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
942 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
943 	used = xdr_skb_read_bits(desc, p, len);
944 	transport->tcp_offset += used;
945 	if (used != len)
946 		return;
947 
948 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
949 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
950 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
951 	else
952 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
953 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
954 
955 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
956 	transport->tcp_offset = 0;
957 
958 	/* Sanity check of the record length */
959 	if (unlikely(transport->tcp_reclen < 4)) {
960 		dprintk("RPC:       invalid TCP record fragment length\n");
961 		xprt_force_disconnect(xprt);
962 		return;
963 	}
964 	dprintk("RPC:       reading TCP record fragment of length %d\n",
965 			transport->tcp_reclen);
966 }
967 
968 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
969 {
970 	if (transport->tcp_offset == transport->tcp_reclen) {
971 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
972 		transport->tcp_offset = 0;
973 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
974 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
975 			transport->tcp_flags |= TCP_RCV_COPY_XID;
976 			transport->tcp_copied = 0;
977 		}
978 	}
979 }
980 
981 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
982 {
983 	size_t len, used;
984 	char *p;
985 
986 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
987 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
988 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
989 	used = xdr_skb_read_bits(desc, p, len);
990 	transport->tcp_offset += used;
991 	if (used != len)
992 		return;
993 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
994 	transport->tcp_flags |= TCP_RCV_COPY_DATA;
995 	transport->tcp_copied = 4;
996 	dprintk("RPC:       reading reply for XID %08x\n",
997 			ntohl(transport->tcp_xid));
998 	xs_tcp_check_fraghdr(transport);
999 }
1000 
1001 static inline void xs_tcp_read_request(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1002 {
1003 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1004 	struct rpc_rqst *req;
1005 	struct xdr_buf *rcvbuf;
1006 	size_t len;
1007 	ssize_t r;
1008 
1009 	/* Find and lock the request corresponding to this xid */
1010 	spin_lock(&xprt->transport_lock);
1011 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1012 	if (!req) {
1013 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1014 		dprintk("RPC:       XID %08x request not found!\n",
1015 				ntohl(transport->tcp_xid));
1016 		spin_unlock(&xprt->transport_lock);
1017 		return;
1018 	}
1019 
1020 	rcvbuf = &req->rq_private_buf;
1021 	len = desc->count;
1022 	if (len > transport->tcp_reclen - transport->tcp_offset) {
1023 		struct xdr_skb_reader my_desc;
1024 
1025 		len = transport->tcp_reclen - transport->tcp_offset;
1026 		memcpy(&my_desc, desc, sizeof(my_desc));
1027 		my_desc.count = len;
1028 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1029 					  &my_desc, xdr_skb_read_bits);
1030 		desc->count -= r;
1031 		desc->offset += r;
1032 	} else
1033 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1034 					  desc, xdr_skb_read_bits);
1035 
1036 	if (r > 0) {
1037 		transport->tcp_copied += r;
1038 		transport->tcp_offset += r;
1039 	}
1040 	if (r != len) {
1041 		/* Error when copying to the receive buffer,
1042 		 * usually because we weren't able to allocate
1043 		 * additional buffer pages. All we can do now
1044 		 * is turn off TCP_RCV_COPY_DATA, so the request
1045 		 * will not receive any additional updates,
1046 		 * and time out.
1047 		 * Any remaining data from this record will
1048 		 * be discarded.
1049 		 */
1050 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1051 		dprintk("RPC:       XID %08x truncated request\n",
1052 				ntohl(transport->tcp_xid));
1053 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1054 				"tcp_offset = %u, tcp_reclen = %u\n",
1055 				xprt, transport->tcp_copied,
1056 				transport->tcp_offset, transport->tcp_reclen);
1057 		goto out;
1058 	}
1059 
1060 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1061 			ntohl(transport->tcp_xid), r);
1062 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1063 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1064 			transport->tcp_offset, transport->tcp_reclen);
1065 
1066 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1067 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1068 	else if (transport->tcp_offset == transport->tcp_reclen) {
1069 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1070 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1071 	}
1072 
1073 out:
1074 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1075 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1076 	spin_unlock(&xprt->transport_lock);
1077 	xs_tcp_check_fraghdr(transport);
1078 }
1079 
1080 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1081 {
1082 	size_t len;
1083 
1084 	len = transport->tcp_reclen - transport->tcp_offset;
1085 	if (len > desc->count)
1086 		len = desc->count;
1087 	desc->count -= len;
1088 	desc->offset += len;
1089 	transport->tcp_offset += len;
1090 	dprintk("RPC:       discarded %Zu bytes\n", len);
1091 	xs_tcp_check_fraghdr(transport);
1092 }
1093 
1094 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1095 {
1096 	struct rpc_xprt *xprt = rd_desc->arg.data;
1097 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1098 	struct xdr_skb_reader desc = {
1099 		.skb	= skb,
1100 		.offset	= offset,
1101 		.count	= len,
1102 	};
1103 
1104 	dprintk("RPC:       xs_tcp_data_recv started\n");
1105 	do {
1106 		/* Read in a new fragment marker if necessary */
1107 		/* Can we ever really expect to get completely empty fragments? */
1108 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1109 			xs_tcp_read_fraghdr(xprt, &desc);
1110 			continue;
1111 		}
1112 		/* Read in the xid if necessary */
1113 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1114 			xs_tcp_read_xid(transport, &desc);
1115 			continue;
1116 		}
1117 		/* Read in the request data */
1118 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1119 			xs_tcp_read_request(xprt, &desc);
1120 			continue;
1121 		}
1122 		/* Skip over any trailing bytes on short reads */
1123 		xs_tcp_read_discard(transport, &desc);
1124 	} while (desc.count);
1125 	dprintk("RPC:       xs_tcp_data_recv done\n");
1126 	return len - desc.count;
1127 }
1128 
1129 /**
1130  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1131  * @sk: socket with data to read
1132  * @bytes: how much data to read
1133  *
1134  */
1135 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1136 {
1137 	struct rpc_xprt *xprt;
1138 	read_descriptor_t rd_desc;
1139 	int read;
1140 
1141 	dprintk("RPC:       xs_tcp_data_ready...\n");
1142 
1143 	read_lock(&sk->sk_callback_lock);
1144 	if (!(xprt = xprt_from_sock(sk)))
1145 		goto out;
1146 	if (xprt->shutdown)
1147 		goto out;
1148 
1149 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1150 	rd_desc.arg.data = xprt;
1151 	do {
1152 		rd_desc.count = 65536;
1153 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1154 	} while (read > 0);
1155 out:
1156 	read_unlock(&sk->sk_callback_lock);
1157 }
1158 
1159 /*
1160  * Do the equivalent of linger/linger2 handling for dealing with
1161  * broken servers that don't close the socket in a timely
1162  * fashion
1163  */
1164 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1165 		unsigned long timeout)
1166 {
1167 	struct sock_xprt *transport;
1168 
1169 	if (xprt_test_and_set_connecting(xprt))
1170 		return;
1171 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1172 	transport = container_of(xprt, struct sock_xprt, xprt);
1173 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1174 			   timeout);
1175 }
1176 
1177 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1178 {
1179 	struct sock_xprt *transport;
1180 
1181 	transport = container_of(xprt, struct sock_xprt, xprt);
1182 
1183 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1184 	    !cancel_delayed_work(&transport->connect_worker))
1185 		return;
1186 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1187 	xprt_clear_connecting(xprt);
1188 }
1189 
1190 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1191 {
1192 	smp_mb__before_clear_bit();
1193 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1194 	clear_bit(XPRT_CLOSING, &xprt->state);
1195 	smp_mb__after_clear_bit();
1196 	/* Mark transport as closed and wake up all pending tasks */
1197 	xprt_disconnect_done(xprt);
1198 }
1199 
1200 /**
1201  * xs_tcp_state_change - callback to handle TCP socket state changes
1202  * @sk: socket whose state has changed
1203  *
1204  */
1205 static void xs_tcp_state_change(struct sock *sk)
1206 {
1207 	struct rpc_xprt *xprt;
1208 
1209 	read_lock(&sk->sk_callback_lock);
1210 	if (!(xprt = xprt_from_sock(sk)))
1211 		goto out;
1212 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1213 	dprintk("RPC:       state %x conn %d dead %d zapped %d\n",
1214 			sk->sk_state, xprt_connected(xprt),
1215 			sock_flag(sk, SOCK_DEAD),
1216 			sock_flag(sk, SOCK_ZAPPED));
1217 
1218 	switch (sk->sk_state) {
1219 	case TCP_ESTABLISHED:
1220 		spin_lock_bh(&xprt->transport_lock);
1221 		if (!xprt_test_and_set_connected(xprt)) {
1222 			struct sock_xprt *transport = container_of(xprt,
1223 					struct sock_xprt, xprt);
1224 
1225 			/* Reset TCP record info */
1226 			transport->tcp_offset = 0;
1227 			transport->tcp_reclen = 0;
1228 			transport->tcp_copied = 0;
1229 			transport->tcp_flags =
1230 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1231 
1232 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1233 		}
1234 		spin_unlock_bh(&xprt->transport_lock);
1235 		break;
1236 	case TCP_FIN_WAIT1:
1237 		/* The client initiated a shutdown of the socket */
1238 		xprt->connect_cookie++;
1239 		xprt->reestablish_timeout = 0;
1240 		set_bit(XPRT_CLOSING, &xprt->state);
1241 		smp_mb__before_clear_bit();
1242 		clear_bit(XPRT_CONNECTED, &xprt->state);
1243 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1244 		smp_mb__after_clear_bit();
1245 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1246 		break;
1247 	case TCP_CLOSE_WAIT:
1248 		/* The server initiated a shutdown of the socket */
1249 		xprt_force_disconnect(xprt);
1250 	case TCP_SYN_SENT:
1251 		xprt->connect_cookie++;
1252 	case TCP_CLOSING:
1253 		/*
1254 		 * If the server closed down the connection, make sure that
1255 		 * we back off before reconnecting
1256 		 */
1257 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1258 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1259 		break;
1260 	case TCP_LAST_ACK:
1261 		set_bit(XPRT_CLOSING, &xprt->state);
1262 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1263 		smp_mb__before_clear_bit();
1264 		clear_bit(XPRT_CONNECTED, &xprt->state);
1265 		smp_mb__after_clear_bit();
1266 		break;
1267 	case TCP_CLOSE:
1268 		xs_tcp_cancel_linger_timeout(xprt);
1269 		xs_sock_mark_closed(xprt);
1270 	}
1271  out:
1272 	read_unlock(&sk->sk_callback_lock);
1273 }
1274 
1275 /**
1276  * xs_error_report - callback mainly for catching socket errors
1277  * @sk: socket
1278  */
1279 static void xs_error_report(struct sock *sk)
1280 {
1281 	struct rpc_xprt *xprt;
1282 
1283 	read_lock(&sk->sk_callback_lock);
1284 	if (!(xprt = xprt_from_sock(sk)))
1285 		goto out;
1286 	dprintk("RPC:       %s client %p...\n"
1287 			"RPC:       error %d\n",
1288 			__func__, xprt, sk->sk_err);
1289 	xprt_wake_pending_tasks(xprt, -EAGAIN);
1290 out:
1291 	read_unlock(&sk->sk_callback_lock);
1292 }
1293 
1294 static void xs_write_space(struct sock *sk)
1295 {
1296 	struct socket *sock;
1297 	struct rpc_xprt *xprt;
1298 
1299 	if (unlikely(!(sock = sk->sk_socket)))
1300 		return;
1301 	clear_bit(SOCK_NOSPACE, &sock->flags);
1302 
1303 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1304 		return;
1305 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1306 		return;
1307 
1308 	xprt_write_space(xprt);
1309 }
1310 
1311 /**
1312  * xs_udp_write_space - callback invoked when socket buffer space
1313  *                             becomes available
1314  * @sk: socket whose state has changed
1315  *
1316  * Called when more output buffer space is available for this socket.
1317  * We try not to wake our writers until they can make "significant"
1318  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1319  * with a bunch of small requests.
1320  */
1321 static void xs_udp_write_space(struct sock *sk)
1322 {
1323 	read_lock(&sk->sk_callback_lock);
1324 
1325 	/* from net/core/sock.c:sock_def_write_space */
1326 	if (sock_writeable(sk))
1327 		xs_write_space(sk);
1328 
1329 	read_unlock(&sk->sk_callback_lock);
1330 }
1331 
1332 /**
1333  * xs_tcp_write_space - callback invoked when socket buffer space
1334  *                             becomes available
1335  * @sk: socket whose state has changed
1336  *
1337  * Called when more output buffer space is available for this socket.
1338  * We try not to wake our writers until they can make "significant"
1339  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1340  * with a bunch of small requests.
1341  */
1342 static void xs_tcp_write_space(struct sock *sk)
1343 {
1344 	read_lock(&sk->sk_callback_lock);
1345 
1346 	/* from net/core/stream.c:sk_stream_write_space */
1347 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1348 		xs_write_space(sk);
1349 
1350 	read_unlock(&sk->sk_callback_lock);
1351 }
1352 
1353 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1354 {
1355 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1356 	struct sock *sk = transport->inet;
1357 
1358 	if (transport->rcvsize) {
1359 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1360 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1361 	}
1362 	if (transport->sndsize) {
1363 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1364 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1365 		sk->sk_write_space(sk);
1366 	}
1367 }
1368 
1369 /**
1370  * xs_udp_set_buffer_size - set send and receive limits
1371  * @xprt: generic transport
1372  * @sndsize: requested size of send buffer, in bytes
1373  * @rcvsize: requested size of receive buffer, in bytes
1374  *
1375  * Set socket send and receive buffer size limits.
1376  */
1377 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1378 {
1379 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1380 
1381 	transport->sndsize = 0;
1382 	if (sndsize)
1383 		transport->sndsize = sndsize + 1024;
1384 	transport->rcvsize = 0;
1385 	if (rcvsize)
1386 		transport->rcvsize = rcvsize + 1024;
1387 
1388 	xs_udp_do_set_buffer_size(xprt);
1389 }
1390 
1391 /**
1392  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1393  * @task: task that timed out
1394  *
1395  * Adjust the congestion window after a retransmit timeout has occurred.
1396  */
1397 static void xs_udp_timer(struct rpc_task *task)
1398 {
1399 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1400 }
1401 
1402 static unsigned short xs_get_random_port(void)
1403 {
1404 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1405 	unsigned short rand = (unsigned short) net_random() % range;
1406 	return rand + xprt_min_resvport;
1407 }
1408 
1409 /**
1410  * xs_set_port - reset the port number in the remote endpoint address
1411  * @xprt: generic transport
1412  * @port: new port number
1413  *
1414  */
1415 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1416 {
1417 	struct sockaddr *addr = xs_addr(xprt);
1418 
1419 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1420 
1421 	switch (addr->sa_family) {
1422 	case AF_INET:
1423 		((struct sockaddr_in *)addr)->sin_port = htons(port);
1424 		break;
1425 	case AF_INET6:
1426 		((struct sockaddr_in6 *)addr)->sin6_port = htons(port);
1427 		break;
1428 	default:
1429 		BUG();
1430 	}
1431 }
1432 
1433 static unsigned short xs_get_srcport(struct sock_xprt *transport, struct socket *sock)
1434 {
1435 	unsigned short port = transport->port;
1436 
1437 	if (port == 0 && transport->xprt.resvport)
1438 		port = xs_get_random_port();
1439 	return port;
1440 }
1441 
1442 static unsigned short xs_next_srcport(struct sock_xprt *transport, struct socket *sock, unsigned short port)
1443 {
1444 	if (transport->port != 0)
1445 		transport->port = 0;
1446 	if (!transport->xprt.resvport)
1447 		return 0;
1448 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1449 		return xprt_max_resvport;
1450 	return --port;
1451 }
1452 
1453 static int xs_bind4(struct sock_xprt *transport, struct socket *sock)
1454 {
1455 	struct sockaddr_in myaddr = {
1456 		.sin_family = AF_INET,
1457 	};
1458 	struct sockaddr_in *sa;
1459 	int err, nloop = 0;
1460 	unsigned short port = xs_get_srcport(transport, sock);
1461 	unsigned short last;
1462 
1463 	sa = (struct sockaddr_in *)&transport->addr;
1464 	myaddr.sin_addr = sa->sin_addr;
1465 	do {
1466 		myaddr.sin_port = htons(port);
1467 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1468 						sizeof(myaddr));
1469 		if (port == 0)
1470 			break;
1471 		if (err == 0) {
1472 			transport->port = port;
1473 			break;
1474 		}
1475 		last = port;
1476 		port = xs_next_srcport(transport, sock, port);
1477 		if (port > last)
1478 			nloop++;
1479 	} while (err == -EADDRINUSE && nloop != 2);
1480 	dprintk("RPC:       %s %pI4:%u: %s (%d)\n",
1481 			__func__, &myaddr.sin_addr,
1482 			port, err ? "failed" : "ok", err);
1483 	return err;
1484 }
1485 
1486 static int xs_bind6(struct sock_xprt *transport, struct socket *sock)
1487 {
1488 	struct sockaddr_in6 myaddr = {
1489 		.sin6_family = AF_INET6,
1490 	};
1491 	struct sockaddr_in6 *sa;
1492 	int err, nloop = 0;
1493 	unsigned short port = xs_get_srcport(transport, sock);
1494 	unsigned short last;
1495 
1496 	sa = (struct sockaddr_in6 *)&transport->addr;
1497 	myaddr.sin6_addr = sa->sin6_addr;
1498 	do {
1499 		myaddr.sin6_port = htons(port);
1500 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1501 						sizeof(myaddr));
1502 		if (port == 0)
1503 			break;
1504 		if (err == 0) {
1505 			transport->port = port;
1506 			break;
1507 		}
1508 		last = port;
1509 		port = xs_next_srcport(transport, sock, port);
1510 		if (port > last)
1511 			nloop++;
1512 	} while (err == -EADDRINUSE && nloop != 2);
1513 	dprintk("RPC:       xs_bind6 %pI6:%u: %s (%d)\n",
1514 		&myaddr.sin6_addr, port, err ? "failed" : "ok", err);
1515 	return err;
1516 }
1517 
1518 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1519 static struct lock_class_key xs_key[2];
1520 static struct lock_class_key xs_slock_key[2];
1521 
1522 static inline void xs_reclassify_socket4(struct socket *sock)
1523 {
1524 	struct sock *sk = sock->sk;
1525 
1526 	BUG_ON(sock_owned_by_user(sk));
1527 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1528 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1529 }
1530 
1531 static inline void xs_reclassify_socket6(struct socket *sock)
1532 {
1533 	struct sock *sk = sock->sk;
1534 
1535 	BUG_ON(sock_owned_by_user(sk));
1536 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1537 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1538 }
1539 #else
1540 static inline void xs_reclassify_socket4(struct socket *sock)
1541 {
1542 }
1543 
1544 static inline void xs_reclassify_socket6(struct socket *sock)
1545 {
1546 }
1547 #endif
1548 
1549 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1550 {
1551 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1552 
1553 	if (!transport->inet) {
1554 		struct sock *sk = sock->sk;
1555 
1556 		write_lock_bh(&sk->sk_callback_lock);
1557 
1558 		xs_save_old_callbacks(transport, sk);
1559 
1560 		sk->sk_user_data = xprt;
1561 		sk->sk_data_ready = xs_udp_data_ready;
1562 		sk->sk_write_space = xs_udp_write_space;
1563 		sk->sk_error_report = xs_error_report;
1564 		sk->sk_no_check = UDP_CSUM_NORCV;
1565 		sk->sk_allocation = GFP_ATOMIC;
1566 
1567 		xprt_set_connected(xprt);
1568 
1569 		/* Reset to new socket */
1570 		transport->sock = sock;
1571 		transport->inet = sk;
1572 
1573 		write_unlock_bh(&sk->sk_callback_lock);
1574 	}
1575 	xs_udp_do_set_buffer_size(xprt);
1576 }
1577 
1578 /**
1579  * xs_udp_connect_worker4 - set up a UDP socket
1580  * @work: RPC transport to connect
1581  *
1582  * Invoked by a work queue tasklet.
1583  */
1584 static void xs_udp_connect_worker4(struct work_struct *work)
1585 {
1586 	struct sock_xprt *transport =
1587 		container_of(work, struct sock_xprt, connect_worker.work);
1588 	struct rpc_xprt *xprt = &transport->xprt;
1589 	struct socket *sock = transport->sock;
1590 	int err, status = -EIO;
1591 
1592 	if (xprt->shutdown)
1593 		goto out;
1594 
1595 	/* Start by resetting any existing state */
1596 	xs_reset_transport(transport);
1597 
1598 	err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
1599 	if (err < 0) {
1600 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1601 		goto out;
1602 	}
1603 	xs_reclassify_socket4(sock);
1604 
1605 	if (xs_bind4(transport, sock)) {
1606 		sock_release(sock);
1607 		goto out;
1608 	}
1609 
1610 	dprintk("RPC:       worker connecting xprt %p to address: %s\n",
1611 			xprt, xprt->address_strings[RPC_DISPLAY_ALL]);
1612 
1613 	xs_udp_finish_connecting(xprt, sock);
1614 	status = 0;
1615 out:
1616 	xprt_clear_connecting(xprt);
1617 	xprt_wake_pending_tasks(xprt, status);
1618 }
1619 
1620 /**
1621  * xs_udp_connect_worker6 - set up a UDP socket
1622  * @work: RPC transport to connect
1623  *
1624  * Invoked by a work queue tasklet.
1625  */
1626 static void xs_udp_connect_worker6(struct work_struct *work)
1627 {
1628 	struct sock_xprt *transport =
1629 		container_of(work, struct sock_xprt, connect_worker.work);
1630 	struct rpc_xprt *xprt = &transport->xprt;
1631 	struct socket *sock = transport->sock;
1632 	int err, status = -EIO;
1633 
1634 	if (xprt->shutdown)
1635 		goto out;
1636 
1637 	/* Start by resetting any existing state */
1638 	xs_reset_transport(transport);
1639 
1640 	err = sock_create_kern(PF_INET6, SOCK_DGRAM, IPPROTO_UDP, &sock);
1641 	if (err < 0) {
1642 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1643 		goto out;
1644 	}
1645 	xs_reclassify_socket6(sock);
1646 
1647 	if (xs_bind6(transport, sock) < 0) {
1648 		sock_release(sock);
1649 		goto out;
1650 	}
1651 
1652 	dprintk("RPC:       worker connecting xprt %p to address: %s\n",
1653 			xprt, xprt->address_strings[RPC_DISPLAY_ALL]);
1654 
1655 	xs_udp_finish_connecting(xprt, sock);
1656 	status = 0;
1657 out:
1658 	xprt_clear_connecting(xprt);
1659 	xprt_wake_pending_tasks(xprt, status);
1660 }
1661 
1662 /*
1663  * We need to preserve the port number so the reply cache on the server can
1664  * find our cached RPC replies when we get around to reconnecting.
1665  */
1666 static void xs_abort_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1667 {
1668 	int result;
1669 	struct sockaddr any;
1670 
1671 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", xprt);
1672 
1673 	/*
1674 	 * Disconnect the transport socket by doing a connect operation
1675 	 * with AF_UNSPEC.  This should return immediately...
1676 	 */
1677 	memset(&any, 0, sizeof(any));
1678 	any.sa_family = AF_UNSPEC;
1679 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
1680 	if (!result)
1681 		xs_sock_mark_closed(xprt);
1682 	else
1683 		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
1684 				result);
1685 }
1686 
1687 static void xs_tcp_reuse_connection(struct rpc_xprt *xprt, struct sock_xprt *transport)
1688 {
1689 	unsigned int state = transport->inet->sk_state;
1690 
1691 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED)
1692 		return;
1693 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT))
1694 		return;
1695 	xs_abort_connection(xprt, transport);
1696 }
1697 
1698 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1699 {
1700 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1701 
1702 	if (!transport->inet) {
1703 		struct sock *sk = sock->sk;
1704 
1705 		write_lock_bh(&sk->sk_callback_lock);
1706 
1707 		xs_save_old_callbacks(transport, sk);
1708 
1709 		sk->sk_user_data = xprt;
1710 		sk->sk_data_ready = xs_tcp_data_ready;
1711 		sk->sk_state_change = xs_tcp_state_change;
1712 		sk->sk_write_space = xs_tcp_write_space;
1713 		sk->sk_error_report = xs_error_report;
1714 		sk->sk_allocation = GFP_ATOMIC;
1715 
1716 		/* socket options */
1717 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1718 		sock_reset_flag(sk, SOCK_LINGER);
1719 		tcp_sk(sk)->linger2 = 0;
1720 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1721 
1722 		xprt_clear_connected(xprt);
1723 
1724 		/* Reset to new socket */
1725 		transport->sock = sock;
1726 		transport->inet = sk;
1727 
1728 		write_unlock_bh(&sk->sk_callback_lock);
1729 	}
1730 
1731 	if (!xprt_bound(xprt))
1732 		return -ENOTCONN;
1733 
1734 	/* Tell the socket layer to start connecting... */
1735 	xprt->stat.connect_count++;
1736 	xprt->stat.connect_start = jiffies;
1737 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
1738 }
1739 
1740 /**
1741  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
1742  * @xprt: RPC transport to connect
1743  * @transport: socket transport to connect
1744  * @create_sock: function to create a socket of the correct type
1745  *
1746  * Invoked by a work queue tasklet.
1747  */
1748 static void xs_tcp_setup_socket(struct rpc_xprt *xprt,
1749 		struct sock_xprt *transport,
1750 		struct socket *(*create_sock)(struct rpc_xprt *,
1751 			struct sock_xprt *))
1752 {
1753 	struct socket *sock = transport->sock;
1754 	int status = -EIO;
1755 
1756 	if (xprt->shutdown)
1757 		goto out;
1758 
1759 	if (!sock) {
1760 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1761 		sock = create_sock(xprt, transport);
1762 		if (IS_ERR(sock)) {
1763 			status = PTR_ERR(sock);
1764 			goto out;
1765 		}
1766 	} else {
1767 		int abort_and_exit;
1768 
1769 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
1770 				&xprt->state);
1771 		/* "close" the socket, preserving the local port */
1772 		xs_tcp_reuse_connection(xprt, transport);
1773 
1774 		if (abort_and_exit)
1775 			goto out_eagain;
1776 	}
1777 
1778 	dprintk("RPC:       worker connecting xprt %p to address: %s\n",
1779 			xprt, xprt->address_strings[RPC_DISPLAY_ALL]);
1780 
1781 	status = xs_tcp_finish_connecting(xprt, sock);
1782 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
1783 			xprt, -status, xprt_connected(xprt),
1784 			sock->sk->sk_state);
1785 	switch (status) {
1786 	default:
1787 		printk("%s: connect returned unhandled error %d\n",
1788 			__func__, status);
1789 	case -EADDRNOTAVAIL:
1790 		/* We're probably in TIME_WAIT. Get rid of existing socket,
1791 		 * and retry
1792 		 */
1793 		set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1794 		xprt_force_disconnect(xprt);
1795 	case -ECONNREFUSED:
1796 	case -ECONNRESET:
1797 	case -ENETUNREACH:
1798 		/* retry with existing socket, after a delay */
1799 	case 0:
1800 	case -EINPROGRESS:
1801 	case -EALREADY:
1802 		xprt_clear_connecting(xprt);
1803 		return;
1804 	}
1805 out_eagain:
1806 	status = -EAGAIN;
1807 out:
1808 	xprt_clear_connecting(xprt);
1809 	xprt_wake_pending_tasks(xprt, status);
1810 }
1811 
1812 static struct socket *xs_create_tcp_sock4(struct rpc_xprt *xprt,
1813 		struct sock_xprt *transport)
1814 {
1815 	struct socket *sock;
1816 	int err;
1817 
1818 	/* start from scratch */
1819 	err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
1820 	if (err < 0) {
1821 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1822 				-err);
1823 		goto out_err;
1824 	}
1825 	xs_reclassify_socket4(sock);
1826 
1827 	if (xs_bind4(transport, sock) < 0) {
1828 		sock_release(sock);
1829 		goto out_err;
1830 	}
1831 	return sock;
1832 out_err:
1833 	return ERR_PTR(-EIO);
1834 }
1835 
1836 /**
1837  * xs_tcp_connect_worker4 - connect a TCP socket to a remote endpoint
1838  * @work: RPC transport to connect
1839  *
1840  * Invoked by a work queue tasklet.
1841  */
1842 static void xs_tcp_connect_worker4(struct work_struct *work)
1843 {
1844 	struct sock_xprt *transport =
1845 		container_of(work, struct sock_xprt, connect_worker.work);
1846 	struct rpc_xprt *xprt = &transport->xprt;
1847 
1848 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock4);
1849 }
1850 
1851 static struct socket *xs_create_tcp_sock6(struct rpc_xprt *xprt,
1852 		struct sock_xprt *transport)
1853 {
1854 	struct socket *sock;
1855 	int err;
1856 
1857 	/* start from scratch */
1858 	err = sock_create_kern(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &sock);
1859 	if (err < 0) {
1860 		dprintk("RPC:       can't create TCP transport socket (%d).\n",
1861 				-err);
1862 		goto out_err;
1863 	}
1864 	xs_reclassify_socket6(sock);
1865 
1866 	if (xs_bind6(transport, sock) < 0) {
1867 		sock_release(sock);
1868 		goto out_err;
1869 	}
1870 	return sock;
1871 out_err:
1872 	return ERR_PTR(-EIO);
1873 }
1874 
1875 /**
1876  * xs_tcp_connect_worker6 - connect a TCP socket to a remote endpoint
1877  * @work: RPC transport to connect
1878  *
1879  * Invoked by a work queue tasklet.
1880  */
1881 static void xs_tcp_connect_worker6(struct work_struct *work)
1882 {
1883 	struct sock_xprt *transport =
1884 		container_of(work, struct sock_xprt, connect_worker.work);
1885 	struct rpc_xprt *xprt = &transport->xprt;
1886 
1887 	xs_tcp_setup_socket(xprt, transport, xs_create_tcp_sock6);
1888 }
1889 
1890 /**
1891  * xs_connect - connect a socket to a remote endpoint
1892  * @task: address of RPC task that manages state of connect request
1893  *
1894  * TCP: If the remote end dropped the connection, delay reconnecting.
1895  *
1896  * UDP socket connects are synchronous, but we use a work queue anyway
1897  * to guarantee that even unprivileged user processes can set up a
1898  * socket on a privileged port.
1899  *
1900  * If a UDP socket connect fails, the delay behavior here prevents
1901  * retry floods (hard mounts).
1902  */
1903 static void xs_connect(struct rpc_task *task)
1904 {
1905 	struct rpc_xprt *xprt = task->tk_xprt;
1906 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1907 
1908 	if (xprt_test_and_set_connecting(xprt))
1909 		return;
1910 
1911 	if (transport->sock != NULL) {
1912 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
1913 				"seconds\n",
1914 				xprt, xprt->reestablish_timeout / HZ);
1915 		queue_delayed_work(rpciod_workqueue,
1916 				   &transport->connect_worker,
1917 				   xprt->reestablish_timeout);
1918 		xprt->reestablish_timeout <<= 1;
1919 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
1920 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
1921 	} else {
1922 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
1923 		queue_delayed_work(rpciod_workqueue,
1924 				   &transport->connect_worker, 0);
1925 	}
1926 }
1927 
1928 static void xs_tcp_connect(struct rpc_task *task)
1929 {
1930 	struct rpc_xprt *xprt = task->tk_xprt;
1931 
1932 	/* Exit if we need to wait for socket shutdown to complete */
1933 	if (test_bit(XPRT_CLOSING, &xprt->state))
1934 		return;
1935 	xs_connect(task);
1936 }
1937 
1938 /**
1939  * xs_udp_print_stats - display UDP socket-specifc stats
1940  * @xprt: rpc_xprt struct containing statistics
1941  * @seq: output file
1942  *
1943  */
1944 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1945 {
1946 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1947 
1948 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
1949 			transport->port,
1950 			xprt->stat.bind_count,
1951 			xprt->stat.sends,
1952 			xprt->stat.recvs,
1953 			xprt->stat.bad_xids,
1954 			xprt->stat.req_u,
1955 			xprt->stat.bklog_u);
1956 }
1957 
1958 /**
1959  * xs_tcp_print_stats - display TCP socket-specifc stats
1960  * @xprt: rpc_xprt struct containing statistics
1961  * @seq: output file
1962  *
1963  */
1964 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1965 {
1966 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1967 	long idle_time = 0;
1968 
1969 	if (xprt_connected(xprt))
1970 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
1971 
1972 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
1973 			transport->port,
1974 			xprt->stat.bind_count,
1975 			xprt->stat.connect_count,
1976 			xprt->stat.connect_time,
1977 			idle_time,
1978 			xprt->stat.sends,
1979 			xprt->stat.recvs,
1980 			xprt->stat.bad_xids,
1981 			xprt->stat.req_u,
1982 			xprt->stat.bklog_u);
1983 }
1984 
1985 static struct rpc_xprt_ops xs_udp_ops = {
1986 	.set_buffer_size	= xs_udp_set_buffer_size,
1987 	.reserve_xprt		= xprt_reserve_xprt_cong,
1988 	.release_xprt		= xprt_release_xprt_cong,
1989 	.rpcbind		= rpcb_getport_async,
1990 	.set_port		= xs_set_port,
1991 	.connect		= xs_connect,
1992 	.buf_alloc		= rpc_malloc,
1993 	.buf_free		= rpc_free,
1994 	.send_request		= xs_udp_send_request,
1995 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
1996 	.timer			= xs_udp_timer,
1997 	.release_request	= xprt_release_rqst_cong,
1998 	.close			= xs_close,
1999 	.destroy		= xs_destroy,
2000 	.print_stats		= xs_udp_print_stats,
2001 };
2002 
2003 static struct rpc_xprt_ops xs_tcp_ops = {
2004 	.reserve_xprt		= xprt_reserve_xprt,
2005 	.release_xprt		= xs_tcp_release_xprt,
2006 	.rpcbind		= rpcb_getport_async,
2007 	.set_port		= xs_set_port,
2008 	.connect		= xs_tcp_connect,
2009 	.buf_alloc		= rpc_malloc,
2010 	.buf_free		= rpc_free,
2011 	.send_request		= xs_tcp_send_request,
2012 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2013 	.close			= xs_tcp_close,
2014 	.destroy		= xs_destroy,
2015 	.print_stats		= xs_tcp_print_stats,
2016 };
2017 
2018 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2019 				      unsigned int slot_table_size)
2020 {
2021 	struct rpc_xprt *xprt;
2022 	struct sock_xprt *new;
2023 
2024 	if (args->addrlen > sizeof(xprt->addr)) {
2025 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2026 		return ERR_PTR(-EBADF);
2027 	}
2028 
2029 	new = kzalloc(sizeof(*new), GFP_KERNEL);
2030 	if (new == NULL) {
2031 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2032 				"rpc_xprt\n");
2033 		return ERR_PTR(-ENOMEM);
2034 	}
2035 	xprt = &new->xprt;
2036 
2037 	xprt->max_reqs = slot_table_size;
2038 	xprt->slot = kcalloc(xprt->max_reqs, sizeof(struct rpc_rqst), GFP_KERNEL);
2039 	if (xprt->slot == NULL) {
2040 		kfree(xprt);
2041 		dprintk("RPC:       xs_setup_xprt: couldn't allocate slot "
2042 				"table\n");
2043 		return ERR_PTR(-ENOMEM);
2044 	}
2045 
2046 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2047 	xprt->addrlen = args->addrlen;
2048 	if (args->srcaddr)
2049 		memcpy(&new->addr, args->srcaddr, args->addrlen);
2050 
2051 	return xprt;
2052 }
2053 
2054 static const struct rpc_timeout xs_udp_default_timeout = {
2055 	.to_initval = 5 * HZ,
2056 	.to_maxval = 30 * HZ,
2057 	.to_increment = 5 * HZ,
2058 	.to_retries = 5,
2059 };
2060 
2061 /**
2062  * xs_setup_udp - Set up transport to use a UDP socket
2063  * @args: rpc transport creation arguments
2064  *
2065  */
2066 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2067 {
2068 	struct sockaddr *addr = args->dstaddr;
2069 	struct rpc_xprt *xprt;
2070 	struct sock_xprt *transport;
2071 
2072 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries);
2073 	if (IS_ERR(xprt))
2074 		return xprt;
2075 	transport = container_of(xprt, struct sock_xprt, xprt);
2076 
2077 	xprt->prot = IPPROTO_UDP;
2078 	xprt->tsh_size = 0;
2079 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2080 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2081 
2082 	xprt->bind_timeout = XS_BIND_TO;
2083 	xprt->connect_timeout = XS_UDP_CONN_TO;
2084 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2085 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2086 
2087 	xprt->ops = &xs_udp_ops;
2088 
2089 	xprt->timeout = &xs_udp_default_timeout;
2090 
2091 	switch (addr->sa_family) {
2092 	case AF_INET:
2093 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2094 			xprt_set_bound(xprt);
2095 
2096 		INIT_DELAYED_WORK(&transport->connect_worker,
2097 					xs_udp_connect_worker4);
2098 		xs_format_ipv4_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2099 		break;
2100 	case AF_INET6:
2101 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2102 			xprt_set_bound(xprt);
2103 
2104 		INIT_DELAYED_WORK(&transport->connect_worker,
2105 					xs_udp_connect_worker6);
2106 		xs_format_ipv6_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2107 		break;
2108 	default:
2109 		kfree(xprt);
2110 		return ERR_PTR(-EAFNOSUPPORT);
2111 	}
2112 
2113 	dprintk("RPC:       set up transport to address %s\n",
2114 			xprt->address_strings[RPC_DISPLAY_ALL]);
2115 
2116 	if (try_module_get(THIS_MODULE))
2117 		return xprt;
2118 
2119 	kfree(xprt->slot);
2120 	kfree(xprt);
2121 	return ERR_PTR(-EINVAL);
2122 }
2123 
2124 static const struct rpc_timeout xs_tcp_default_timeout = {
2125 	.to_initval = 60 * HZ,
2126 	.to_maxval = 60 * HZ,
2127 	.to_retries = 2,
2128 };
2129 
2130 /**
2131  * xs_setup_tcp - Set up transport to use a TCP socket
2132  * @args: rpc transport creation arguments
2133  *
2134  */
2135 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2136 {
2137 	struct sockaddr *addr = args->dstaddr;
2138 	struct rpc_xprt *xprt;
2139 	struct sock_xprt *transport;
2140 
2141 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
2142 	if (IS_ERR(xprt))
2143 		return xprt;
2144 	transport = container_of(xprt, struct sock_xprt, xprt);
2145 
2146 	xprt->prot = IPPROTO_TCP;
2147 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2148 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2149 
2150 	xprt->bind_timeout = XS_BIND_TO;
2151 	xprt->connect_timeout = XS_TCP_CONN_TO;
2152 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2153 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2154 
2155 	xprt->ops = &xs_tcp_ops;
2156 	xprt->timeout = &xs_tcp_default_timeout;
2157 
2158 	switch (addr->sa_family) {
2159 	case AF_INET:
2160 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2161 			xprt_set_bound(xprt);
2162 
2163 		INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_connect_worker4);
2164 		xs_format_ipv4_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2165 		break;
2166 	case AF_INET6:
2167 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2168 			xprt_set_bound(xprt);
2169 
2170 		INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_connect_worker6);
2171 		xs_format_ipv6_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2172 		break;
2173 	default:
2174 		kfree(xprt);
2175 		return ERR_PTR(-EAFNOSUPPORT);
2176 	}
2177 
2178 	dprintk("RPC:       set up transport to address %s\n",
2179 			xprt->address_strings[RPC_DISPLAY_ALL]);
2180 
2181 	if (try_module_get(THIS_MODULE))
2182 		return xprt;
2183 
2184 	kfree(xprt->slot);
2185 	kfree(xprt);
2186 	return ERR_PTR(-EINVAL);
2187 }
2188 
2189 static struct xprt_class	xs_udp_transport = {
2190 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2191 	.name		= "udp",
2192 	.owner		= THIS_MODULE,
2193 	.ident		= IPPROTO_UDP,
2194 	.setup		= xs_setup_udp,
2195 };
2196 
2197 static struct xprt_class	xs_tcp_transport = {
2198 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2199 	.name		= "tcp",
2200 	.owner		= THIS_MODULE,
2201 	.ident		= IPPROTO_TCP,
2202 	.setup		= xs_setup_tcp,
2203 };
2204 
2205 /**
2206  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2207  *
2208  */
2209 int init_socket_xprt(void)
2210 {
2211 #ifdef RPC_DEBUG
2212 	if (!sunrpc_table_header)
2213 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2214 #endif
2215 
2216 	xprt_register_transport(&xs_udp_transport);
2217 	xprt_register_transport(&xs_tcp_transport);
2218 
2219 	return 0;
2220 }
2221 
2222 /**
2223  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2224  *
2225  */
2226 void cleanup_socket_xprt(void)
2227 {
2228 #ifdef RPC_DEBUG
2229 	if (sunrpc_table_header) {
2230 		unregister_sysctl_table(sunrpc_table_header);
2231 		sunrpc_table_header = NULL;
2232 	}
2233 #endif
2234 
2235 	xprt_unregister_transport(&xs_udp_transport);
2236 	xprt_unregister_transport(&xs_tcp_transport);
2237 }
2238