xref: /linux/net/sunrpc/xprtsock.c (revision 2b8232ce512105e28453f301d1510de8363bccd1)
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 Software <alan@redhat.com>
7  * TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
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 
18 #include <linux/types.h>
19 #include <linux/slab.h>
20 #include <linux/capability.h>
21 #include <linux/pagemap.h>
22 #include <linux/errno.h>
23 #include <linux/socket.h>
24 #include <linux/in.h>
25 #include <linux/net.h>
26 #include <linux/mm.h>
27 #include <linux/udp.h>
28 #include <linux/tcp.h>
29 #include <linux/sunrpc/clnt.h>
30 #include <linux/sunrpc/sched.h>
31 #include <linux/file.h>
32 
33 #include <net/sock.h>
34 #include <net/checksum.h>
35 #include <net/udp.h>
36 #include <net/tcp.h>
37 
38 /*
39  * xprtsock tunables
40  */
41 unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
42 unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
43 
44 unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
45 unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
46 
47 /*
48  * We can register our own files under /proc/sys/sunrpc by
49  * calling register_sysctl_table() again.  The files in that
50  * directory become the union of all files registered there.
51  *
52  * We simply need to make sure that we don't collide with
53  * someone else's file names!
54  */
55 
56 #ifdef RPC_DEBUG
57 
58 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
59 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
60 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
61 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
62 
63 static struct ctl_table_header *sunrpc_table_header;
64 
65 /*
66  * FIXME: changing the UDP slot table size should also resize the UDP
67  *        socket buffers for existing UDP transports
68  */
69 static ctl_table xs_tunables_table[] = {
70 	{
71 		.ctl_name	= CTL_SLOTTABLE_UDP,
72 		.procname	= "udp_slot_table_entries",
73 		.data		= &xprt_udp_slot_table_entries,
74 		.maxlen		= sizeof(unsigned int),
75 		.mode		= 0644,
76 		.proc_handler	= &proc_dointvec_minmax,
77 		.strategy	= &sysctl_intvec,
78 		.extra1		= &min_slot_table_size,
79 		.extra2		= &max_slot_table_size
80 	},
81 	{
82 		.ctl_name	= CTL_SLOTTABLE_TCP,
83 		.procname	= "tcp_slot_table_entries",
84 		.data		= &xprt_tcp_slot_table_entries,
85 		.maxlen		= sizeof(unsigned int),
86 		.mode		= 0644,
87 		.proc_handler	= &proc_dointvec_minmax,
88 		.strategy	= &sysctl_intvec,
89 		.extra1		= &min_slot_table_size,
90 		.extra2		= &max_slot_table_size
91 	},
92 	{
93 		.ctl_name	= CTL_MIN_RESVPORT,
94 		.procname	= "min_resvport",
95 		.data		= &xprt_min_resvport,
96 		.maxlen		= sizeof(unsigned int),
97 		.mode		= 0644,
98 		.proc_handler	= &proc_dointvec_minmax,
99 		.strategy	= &sysctl_intvec,
100 		.extra1		= &xprt_min_resvport_limit,
101 		.extra2		= &xprt_max_resvport_limit
102 	},
103 	{
104 		.ctl_name	= CTL_MAX_RESVPORT,
105 		.procname	= "max_resvport",
106 		.data		= &xprt_max_resvport,
107 		.maxlen		= sizeof(unsigned int),
108 		.mode		= 0644,
109 		.proc_handler	= &proc_dointvec_minmax,
110 		.strategy	= &sysctl_intvec,
111 		.extra1		= &xprt_min_resvport_limit,
112 		.extra2		= &xprt_max_resvport_limit
113 	},
114 	{
115 		.ctl_name = 0,
116 	},
117 };
118 
119 static ctl_table sunrpc_table[] = {
120 	{
121 		.ctl_name	= CTL_SUNRPC,
122 		.procname	= "sunrpc",
123 		.mode		= 0555,
124 		.child		= xs_tunables_table
125 	},
126 	{
127 		.ctl_name = 0,
128 	},
129 };
130 
131 #endif
132 
133 /*
134  * How many times to try sending a request on a socket before waiting
135  * for the socket buffer to clear.
136  */
137 #define XS_SENDMSG_RETRY	(10U)
138 
139 /*
140  * Time out for an RPC UDP socket connect.  UDP socket connects are
141  * synchronous, but we set a timeout anyway in case of resource
142  * exhaustion on the local host.
143  */
144 #define XS_UDP_CONN_TO		(5U * HZ)
145 
146 /*
147  * Wait duration for an RPC TCP connection to be established.  Solaris
148  * NFS over TCP uses 60 seconds, for example, which is in line with how
149  * long a server takes to reboot.
150  */
151 #define XS_TCP_CONN_TO		(60U * HZ)
152 
153 /*
154  * Wait duration for a reply from the RPC portmapper.
155  */
156 #define XS_BIND_TO		(60U * HZ)
157 
158 /*
159  * Delay if a UDP socket connect error occurs.  This is most likely some
160  * kind of resource problem on the local host.
161  */
162 #define XS_UDP_REEST_TO		(2U * HZ)
163 
164 /*
165  * The reestablish timeout allows clients to delay for a bit before attempting
166  * to reconnect to a server that just dropped our connection.
167  *
168  * We implement an exponential backoff when trying to reestablish a TCP
169  * transport connection with the server.  Some servers like to drop a TCP
170  * connection when they are overworked, so we start with a short timeout and
171  * increase over time if the server is down or not responding.
172  */
173 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
174 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
175 
176 /*
177  * TCP idle timeout; client drops the transport socket if it is idle
178  * for this long.  Note that we also timeout UDP sockets to prevent
179  * holding port numbers when there is no RPC traffic.
180  */
181 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
182 
183 #ifdef RPC_DEBUG
184 # undef  RPC_DEBUG_DATA
185 # define RPCDBG_FACILITY	RPCDBG_TRANS
186 #endif
187 
188 #ifdef RPC_DEBUG_DATA
189 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
190 {
191 	u8 *buf = (u8 *) packet;
192 	int j;
193 
194 	dprintk("RPC:       %s\n", msg);
195 	for (j = 0; j < count && j < 128; j += 4) {
196 		if (!(j & 31)) {
197 			if (j)
198 				dprintk("\n");
199 			dprintk("0x%04x ", j);
200 		}
201 		dprintk("%02x%02x%02x%02x ",
202 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
203 	}
204 	dprintk("\n");
205 }
206 #else
207 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
208 {
209 	/* NOP */
210 }
211 #endif
212 
213 struct sock_xprt {
214 	struct rpc_xprt		xprt;
215 
216 	/*
217 	 * Network layer
218 	 */
219 	struct socket *		sock;
220 	struct sock *		inet;
221 
222 	/*
223 	 * State of TCP reply receive
224 	 */
225 	__be32			tcp_fraghdr,
226 				tcp_xid;
227 
228 	u32			tcp_offset,
229 				tcp_reclen;
230 
231 	unsigned long		tcp_copied,
232 				tcp_flags;
233 
234 	/*
235 	 * Connection of transports
236 	 */
237 	struct delayed_work	connect_worker;
238 	struct sockaddr_storage	addr;
239 	unsigned short		port;
240 
241 	/*
242 	 * UDP socket buffer size parameters
243 	 */
244 	size_t			rcvsize,
245 				sndsize;
246 
247 	/*
248 	 * Saved socket callback addresses
249 	 */
250 	void			(*old_data_ready)(struct sock *, int);
251 	void			(*old_state_change)(struct sock *);
252 	void			(*old_write_space)(struct sock *);
253 };
254 
255 /*
256  * TCP receive state flags
257  */
258 #define TCP_RCV_LAST_FRAG	(1UL << 0)
259 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
260 #define TCP_RCV_COPY_XID	(1UL << 2)
261 #define TCP_RCV_COPY_DATA	(1UL << 3)
262 
263 static void xs_format_peer_addresses(struct rpc_xprt *xprt)
264 {
265 	struct sockaddr_in *addr = (struct sockaddr_in *) &xprt->addr;
266 	char *buf;
267 
268 	buf = kzalloc(20, GFP_KERNEL);
269 	if (buf) {
270 		snprintf(buf, 20, "%u.%u.%u.%u",
271 				NIPQUAD(addr->sin_addr.s_addr));
272 	}
273 	xprt->address_strings[RPC_DISPLAY_ADDR] = buf;
274 
275 	buf = kzalloc(8, GFP_KERNEL);
276 	if (buf) {
277 		snprintf(buf, 8, "%u",
278 				ntohs(addr->sin_port));
279 	}
280 	xprt->address_strings[RPC_DISPLAY_PORT] = buf;
281 
282 	if (xprt->prot == IPPROTO_UDP)
283 		xprt->address_strings[RPC_DISPLAY_PROTO] = "udp";
284 	else
285 		xprt->address_strings[RPC_DISPLAY_PROTO] = "tcp";
286 
287 	buf = kzalloc(48, GFP_KERNEL);
288 	if (buf) {
289 		snprintf(buf, 48, "addr=%u.%u.%u.%u port=%u proto=%s",
290 			NIPQUAD(addr->sin_addr.s_addr),
291 			ntohs(addr->sin_port),
292 			xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
293 	}
294 	xprt->address_strings[RPC_DISPLAY_ALL] = buf;
295 }
296 
297 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
298 {
299 	kfree(xprt->address_strings[RPC_DISPLAY_ADDR]);
300 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
301 	kfree(xprt->address_strings[RPC_DISPLAY_ALL]);
302 }
303 
304 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
305 
306 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
307 {
308 	struct msghdr msg = {
309 		.msg_name	= addr,
310 		.msg_namelen	= addrlen,
311 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
312 	};
313 	struct kvec iov = {
314 		.iov_base	= vec->iov_base + base,
315 		.iov_len	= vec->iov_len - base,
316 	};
317 
318 	if (iov.iov_len != 0)
319 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
320 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
321 }
322 
323 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
324 {
325 	struct page **ppage;
326 	unsigned int remainder;
327 	int err, sent = 0;
328 
329 	remainder = xdr->page_len - base;
330 	base += xdr->page_base;
331 	ppage = xdr->pages + (base >> PAGE_SHIFT);
332 	base &= ~PAGE_MASK;
333 	for(;;) {
334 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
335 		int flags = XS_SENDMSG_FLAGS;
336 
337 		remainder -= len;
338 		if (remainder != 0 || more)
339 			flags |= MSG_MORE;
340 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
341 		if (remainder == 0 || err != len)
342 			break;
343 		sent += err;
344 		ppage++;
345 		base = 0;
346 	}
347 	if (sent == 0)
348 		return err;
349 	if (err > 0)
350 		sent += err;
351 	return sent;
352 }
353 
354 /**
355  * xs_sendpages - write pages directly to a socket
356  * @sock: socket to send on
357  * @addr: UDP only -- address of destination
358  * @addrlen: UDP only -- length of destination address
359  * @xdr: buffer containing this request
360  * @base: starting position in the buffer
361  *
362  */
363 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
364 {
365 	unsigned int remainder = xdr->len - base;
366 	int err, sent = 0;
367 
368 	if (unlikely(!sock))
369 		return -ENOTCONN;
370 
371 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
372 	if (base != 0) {
373 		addr = NULL;
374 		addrlen = 0;
375 	}
376 
377 	if (base < xdr->head[0].iov_len || addr != NULL) {
378 		unsigned int len = xdr->head[0].iov_len - base;
379 		remainder -= len;
380 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
381 		if (remainder == 0 || err != len)
382 			goto out;
383 		sent += err;
384 		base = 0;
385 	} else
386 		base -= xdr->head[0].iov_len;
387 
388 	if (base < xdr->page_len) {
389 		unsigned int len = xdr->page_len - base;
390 		remainder -= len;
391 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
392 		if (remainder == 0 || err != len)
393 			goto out;
394 		sent += err;
395 		base = 0;
396 	} else
397 		base -= xdr->page_len;
398 
399 	if (base >= xdr->tail[0].iov_len)
400 		return sent;
401 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
402 out:
403 	if (sent == 0)
404 		return err;
405 	if (err > 0)
406 		sent += err;
407 	return sent;
408 }
409 
410 /**
411  * xs_nospace - place task on wait queue if transmit was incomplete
412  * @task: task to put to sleep
413  *
414  */
415 static void xs_nospace(struct rpc_task *task)
416 {
417 	struct rpc_rqst *req = task->tk_rqstp;
418 	struct rpc_xprt *xprt = req->rq_xprt;
419 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
420 
421 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
422 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
423 			req->rq_slen);
424 
425 	if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
426 		/* Protect against races with write_space */
427 		spin_lock_bh(&xprt->transport_lock);
428 
429 		/* Don't race with disconnect */
430 		if (!xprt_connected(xprt))
431 			task->tk_status = -ENOTCONN;
432 		else if (test_bit(SOCK_NOSPACE, &transport->sock->flags))
433 			xprt_wait_for_buffer_space(task);
434 
435 		spin_unlock_bh(&xprt->transport_lock);
436 	} else
437 		/* Keep holding the socket if it is blocked */
438 		rpc_delay(task, HZ>>4);
439 }
440 
441 /**
442  * xs_udp_send_request - write an RPC request to a UDP socket
443  * @task: address of RPC task that manages the state of an RPC request
444  *
445  * Return values:
446  *        0:	The request has been sent
447  *   EAGAIN:	The socket was blocked, please call again later to
448  *		complete the request
449  * ENOTCONN:	Caller needs to invoke connect logic then call again
450  *    other:	Some other error occured, the request was not sent
451  */
452 static int xs_udp_send_request(struct rpc_task *task)
453 {
454 	struct rpc_rqst *req = task->tk_rqstp;
455 	struct rpc_xprt *xprt = req->rq_xprt;
456 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
457 	struct xdr_buf *xdr = &req->rq_snd_buf;
458 	int status;
459 
460 	xs_pktdump("packet data:",
461 				req->rq_svec->iov_base,
462 				req->rq_svec->iov_len);
463 
464 	req->rq_xtime = jiffies;
465 	status = xs_sendpages(transport->sock,
466 			      (struct sockaddr *) &xprt->addr,
467 			      xprt->addrlen, xdr,
468 			      req->rq_bytes_sent);
469 
470 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
471 			xdr->len - req->rq_bytes_sent, status);
472 
473 	if (likely(status >= (int) req->rq_slen))
474 		return 0;
475 
476 	/* Still some bytes left; set up for a retry later. */
477 	if (status > 0)
478 		status = -EAGAIN;
479 
480 	switch (status) {
481 	case -ENETUNREACH:
482 	case -EPIPE:
483 	case -ECONNREFUSED:
484 		/* When the server has died, an ICMP port unreachable message
485 		 * prompts ECONNREFUSED. */
486 		break;
487 	case -EAGAIN:
488 		xs_nospace(task);
489 		break;
490 	default:
491 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
492 			-status);
493 		break;
494 	}
495 
496 	return status;
497 }
498 
499 static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
500 {
501 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
502 	rpc_fraghdr *base = buf->head[0].iov_base;
503 	*base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
504 }
505 
506 /**
507  * xs_tcp_send_request - write an RPC request to a TCP socket
508  * @task: address of RPC task that manages the state of an RPC request
509  *
510  * Return values:
511  *        0:	The request has been sent
512  *   EAGAIN:	The socket was blocked, please call again later to
513  *		complete the request
514  * ENOTCONN:	Caller needs to invoke connect logic then call again
515  *    other:	Some other error occured, the request was not sent
516  *
517  * XXX: In the case of soft timeouts, should we eventually give up
518  *	if sendmsg is not able to make progress?
519  */
520 static int xs_tcp_send_request(struct rpc_task *task)
521 {
522 	struct rpc_rqst *req = task->tk_rqstp;
523 	struct rpc_xprt *xprt = req->rq_xprt;
524 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
525 	struct xdr_buf *xdr = &req->rq_snd_buf;
526 	int status, retry = 0;
527 
528 	xs_encode_tcp_record_marker(&req->rq_snd_buf);
529 
530 	xs_pktdump("packet data:",
531 				req->rq_svec->iov_base,
532 				req->rq_svec->iov_len);
533 
534 	/* Continue transmitting the packet/record. We must be careful
535 	 * to cope with writespace callbacks arriving _after_ we have
536 	 * called sendmsg(). */
537 	while (1) {
538 		req->rq_xtime = jiffies;
539 		status = xs_sendpages(transport->sock,
540 					NULL, 0, xdr, req->rq_bytes_sent);
541 
542 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
543 				xdr->len - req->rq_bytes_sent, status);
544 
545 		if (unlikely(status < 0))
546 			break;
547 
548 		/* If we've sent the entire packet, immediately
549 		 * reset the count of bytes sent. */
550 		req->rq_bytes_sent += status;
551 		task->tk_bytes_sent += status;
552 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
553 			req->rq_bytes_sent = 0;
554 			return 0;
555 		}
556 
557 		status = -EAGAIN;
558 		if (retry++ > XS_SENDMSG_RETRY)
559 			break;
560 	}
561 
562 	switch (status) {
563 	case -EAGAIN:
564 		xs_nospace(task);
565 		break;
566 	case -ECONNREFUSED:
567 	case -ECONNRESET:
568 	case -ENOTCONN:
569 	case -EPIPE:
570 		status = -ENOTCONN;
571 		break;
572 	default:
573 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
574 			-status);
575 		xprt_disconnect(xprt);
576 		break;
577 	}
578 
579 	return status;
580 }
581 
582 /**
583  * xs_tcp_release_xprt - clean up after a tcp transmission
584  * @xprt: transport
585  * @task: rpc task
586  *
587  * This cleans up if an error causes us to abort the transmission of a request.
588  * In this case, the socket may need to be reset in order to avoid confusing
589  * the server.
590  */
591 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
592 {
593 	struct rpc_rqst *req;
594 
595 	if (task != xprt->snd_task)
596 		return;
597 	if (task == NULL)
598 		goto out_release;
599 	req = task->tk_rqstp;
600 	if (req->rq_bytes_sent == 0)
601 		goto out_release;
602 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
603 		goto out_release;
604 	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
605 out_release:
606 	xprt_release_xprt(xprt, task);
607 }
608 
609 /**
610  * xs_close - close a socket
611  * @xprt: transport
612  *
613  * This is used when all requests are complete; ie, no DRC state remains
614  * on the server we want to save.
615  */
616 static void xs_close(struct rpc_xprt *xprt)
617 {
618 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
619 	struct socket *sock = transport->sock;
620 	struct sock *sk = transport->inet;
621 
622 	if (!sk)
623 		goto clear_close_wait;
624 
625 	dprintk("RPC:       xs_close xprt %p\n", xprt);
626 
627 	write_lock_bh(&sk->sk_callback_lock);
628 	transport->inet = NULL;
629 	transport->sock = NULL;
630 
631 	sk->sk_user_data = NULL;
632 	sk->sk_data_ready = transport->old_data_ready;
633 	sk->sk_state_change = transport->old_state_change;
634 	sk->sk_write_space = transport->old_write_space;
635 	write_unlock_bh(&sk->sk_callback_lock);
636 
637 	sk->sk_no_check = 0;
638 
639 	sock_release(sock);
640 clear_close_wait:
641 	smp_mb__before_clear_bit();
642 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
643 	smp_mb__after_clear_bit();
644 }
645 
646 /**
647  * xs_destroy - prepare to shutdown a transport
648  * @xprt: doomed transport
649  *
650  */
651 static void xs_destroy(struct rpc_xprt *xprt)
652 {
653 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
654 
655 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
656 
657 	cancel_rearming_delayed_work(&transport->connect_worker);
658 
659 	xprt_disconnect(xprt);
660 	xs_close(xprt);
661 	xs_free_peer_addresses(xprt);
662 	kfree(xprt->slot);
663 	kfree(xprt);
664 }
665 
666 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
667 {
668 	return (struct rpc_xprt *) sk->sk_user_data;
669 }
670 
671 /**
672  * xs_udp_data_ready - "data ready" callback for UDP sockets
673  * @sk: socket with data to read
674  * @len: how much data to read
675  *
676  */
677 static void xs_udp_data_ready(struct sock *sk, int len)
678 {
679 	struct rpc_task *task;
680 	struct rpc_xprt *xprt;
681 	struct rpc_rqst *rovr;
682 	struct sk_buff *skb;
683 	int err, repsize, copied;
684 	u32 _xid;
685 	__be32 *xp;
686 
687 	read_lock(&sk->sk_callback_lock);
688 	dprintk("RPC:       xs_udp_data_ready...\n");
689 	if (!(xprt = xprt_from_sock(sk)))
690 		goto out;
691 
692 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
693 		goto out;
694 
695 	if (xprt->shutdown)
696 		goto dropit;
697 
698 	repsize = skb->len - sizeof(struct udphdr);
699 	if (repsize < 4) {
700 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
701 		goto dropit;
702 	}
703 
704 	/* Copy the XID from the skb... */
705 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
706 				sizeof(_xid), &_xid);
707 	if (xp == NULL)
708 		goto dropit;
709 
710 	/* Look up and lock the request corresponding to the given XID */
711 	spin_lock(&xprt->transport_lock);
712 	rovr = xprt_lookup_rqst(xprt, *xp);
713 	if (!rovr)
714 		goto out_unlock;
715 	task = rovr->rq_task;
716 
717 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
718 		copied = repsize;
719 
720 	/* Suck it into the iovec, verify checksum if not done by hw. */
721 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb))
722 		goto out_unlock;
723 
724 	/* Something worked... */
725 	dst_confirm(skb->dst);
726 
727 	xprt_adjust_cwnd(task, copied);
728 	xprt_update_rtt(task);
729 	xprt_complete_rqst(task, copied);
730 
731  out_unlock:
732 	spin_unlock(&xprt->transport_lock);
733  dropit:
734 	skb_free_datagram(sk, skb);
735  out:
736 	read_unlock(&sk->sk_callback_lock);
737 }
738 
739 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
740 {
741 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
742 	size_t len, used;
743 	char *p;
744 
745 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
746 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
747 	used = xdr_skb_read_bits(desc, p, len);
748 	transport->tcp_offset += used;
749 	if (used != len)
750 		return;
751 
752 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
753 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
754 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
755 	else
756 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
757 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
758 
759 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
760 	transport->tcp_offset = 0;
761 
762 	/* Sanity check of the record length */
763 	if (unlikely(transport->tcp_reclen < 4)) {
764 		dprintk("RPC:       invalid TCP record fragment length\n");
765 		xprt_disconnect(xprt);
766 		return;
767 	}
768 	dprintk("RPC:       reading TCP record fragment of length %d\n",
769 			transport->tcp_reclen);
770 }
771 
772 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
773 {
774 	if (transport->tcp_offset == transport->tcp_reclen) {
775 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
776 		transport->tcp_offset = 0;
777 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
778 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
779 			transport->tcp_flags |= TCP_RCV_COPY_XID;
780 			transport->tcp_copied = 0;
781 		}
782 	}
783 }
784 
785 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
786 {
787 	size_t len, used;
788 	char *p;
789 
790 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
791 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
792 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
793 	used = xdr_skb_read_bits(desc, p, len);
794 	transport->tcp_offset += used;
795 	if (used != len)
796 		return;
797 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
798 	transport->tcp_flags |= TCP_RCV_COPY_DATA;
799 	transport->tcp_copied = 4;
800 	dprintk("RPC:       reading reply for XID %08x\n",
801 			ntohl(transport->tcp_xid));
802 	xs_tcp_check_fraghdr(transport);
803 }
804 
805 static inline void xs_tcp_read_request(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
806 {
807 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
808 	struct rpc_rqst *req;
809 	struct xdr_buf *rcvbuf;
810 	size_t len;
811 	ssize_t r;
812 
813 	/* Find and lock the request corresponding to this xid */
814 	spin_lock(&xprt->transport_lock);
815 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
816 	if (!req) {
817 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
818 		dprintk("RPC:       XID %08x request not found!\n",
819 				ntohl(transport->tcp_xid));
820 		spin_unlock(&xprt->transport_lock);
821 		return;
822 	}
823 
824 	rcvbuf = &req->rq_private_buf;
825 	len = desc->count;
826 	if (len > transport->tcp_reclen - transport->tcp_offset) {
827 		struct xdr_skb_reader my_desc;
828 
829 		len = transport->tcp_reclen - transport->tcp_offset;
830 		memcpy(&my_desc, desc, sizeof(my_desc));
831 		my_desc.count = len;
832 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
833 					  &my_desc, xdr_skb_read_bits);
834 		desc->count -= r;
835 		desc->offset += r;
836 	} else
837 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
838 					  desc, xdr_skb_read_bits);
839 
840 	if (r > 0) {
841 		transport->tcp_copied += r;
842 		transport->tcp_offset += r;
843 	}
844 	if (r != len) {
845 		/* Error when copying to the receive buffer,
846 		 * usually because we weren't able to allocate
847 		 * additional buffer pages. All we can do now
848 		 * is turn off TCP_RCV_COPY_DATA, so the request
849 		 * will not receive any additional updates,
850 		 * and time out.
851 		 * Any remaining data from this record will
852 		 * be discarded.
853 		 */
854 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
855 		dprintk("RPC:       XID %08x truncated request\n",
856 				ntohl(transport->tcp_xid));
857 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
858 				"tcp_offset = %u, tcp_reclen = %u\n",
859 				xprt, transport->tcp_copied,
860 				transport->tcp_offset, transport->tcp_reclen);
861 		goto out;
862 	}
863 
864 	dprintk("RPC:       XID %08x read %Zd bytes\n",
865 			ntohl(transport->tcp_xid), r);
866 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
867 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
868 			transport->tcp_offset, transport->tcp_reclen);
869 
870 	if (transport->tcp_copied == req->rq_private_buf.buflen)
871 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
872 	else if (transport->tcp_offset == transport->tcp_reclen) {
873 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
874 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
875 	}
876 
877 out:
878 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
879 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
880 	spin_unlock(&xprt->transport_lock);
881 	xs_tcp_check_fraghdr(transport);
882 }
883 
884 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
885 {
886 	size_t len;
887 
888 	len = transport->tcp_reclen - transport->tcp_offset;
889 	if (len > desc->count)
890 		len = desc->count;
891 	desc->count -= len;
892 	desc->offset += len;
893 	transport->tcp_offset += len;
894 	dprintk("RPC:       discarded %Zu bytes\n", len);
895 	xs_tcp_check_fraghdr(transport);
896 }
897 
898 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
899 {
900 	struct rpc_xprt *xprt = rd_desc->arg.data;
901 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
902 	struct xdr_skb_reader desc = {
903 		.skb	= skb,
904 		.offset	= offset,
905 		.count	= len,
906 	};
907 
908 	dprintk("RPC:       xs_tcp_data_recv started\n");
909 	do {
910 		/* Read in a new fragment marker if necessary */
911 		/* Can we ever really expect to get completely empty fragments? */
912 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
913 			xs_tcp_read_fraghdr(xprt, &desc);
914 			continue;
915 		}
916 		/* Read in the xid if necessary */
917 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
918 			xs_tcp_read_xid(transport, &desc);
919 			continue;
920 		}
921 		/* Read in the request data */
922 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
923 			xs_tcp_read_request(xprt, &desc);
924 			continue;
925 		}
926 		/* Skip over any trailing bytes on short reads */
927 		xs_tcp_read_discard(transport, &desc);
928 	} while (desc.count);
929 	dprintk("RPC:       xs_tcp_data_recv done\n");
930 	return len - desc.count;
931 }
932 
933 /**
934  * xs_tcp_data_ready - "data ready" callback for TCP sockets
935  * @sk: socket with data to read
936  * @bytes: how much data to read
937  *
938  */
939 static void xs_tcp_data_ready(struct sock *sk, int bytes)
940 {
941 	struct rpc_xprt *xprt;
942 	read_descriptor_t rd_desc;
943 
944 	dprintk("RPC:       xs_tcp_data_ready...\n");
945 
946 	read_lock(&sk->sk_callback_lock);
947 	if (!(xprt = xprt_from_sock(sk)))
948 		goto out;
949 	if (xprt->shutdown)
950 		goto out;
951 
952 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
953 	rd_desc.arg.data = xprt;
954 	rd_desc.count = 65536;
955 	tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
956 out:
957 	read_unlock(&sk->sk_callback_lock);
958 }
959 
960 /**
961  * xs_tcp_state_change - callback to handle TCP socket state changes
962  * @sk: socket whose state has changed
963  *
964  */
965 static void xs_tcp_state_change(struct sock *sk)
966 {
967 	struct rpc_xprt *xprt;
968 
969 	read_lock(&sk->sk_callback_lock);
970 	if (!(xprt = xprt_from_sock(sk)))
971 		goto out;
972 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
973 	dprintk("RPC:       state %x conn %d dead %d zapped %d\n",
974 			sk->sk_state, xprt_connected(xprt),
975 			sock_flag(sk, SOCK_DEAD),
976 			sock_flag(sk, SOCK_ZAPPED));
977 
978 	switch (sk->sk_state) {
979 	case TCP_ESTABLISHED:
980 		spin_lock_bh(&xprt->transport_lock);
981 		if (!xprt_test_and_set_connected(xprt)) {
982 			struct sock_xprt *transport = container_of(xprt,
983 					struct sock_xprt, xprt);
984 
985 			/* Reset TCP record info */
986 			transport->tcp_offset = 0;
987 			transport->tcp_reclen = 0;
988 			transport->tcp_copied = 0;
989 			transport->tcp_flags =
990 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
991 
992 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
993 			xprt_wake_pending_tasks(xprt, 0);
994 		}
995 		spin_unlock_bh(&xprt->transport_lock);
996 		break;
997 	case TCP_SYN_SENT:
998 	case TCP_SYN_RECV:
999 		break;
1000 	case TCP_CLOSE_WAIT:
1001 		/* Try to schedule an autoclose RPC calls */
1002 		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
1003 		if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0)
1004 			queue_work(rpciod_workqueue, &xprt->task_cleanup);
1005 	default:
1006 		xprt_disconnect(xprt);
1007 	}
1008  out:
1009 	read_unlock(&sk->sk_callback_lock);
1010 }
1011 
1012 /**
1013  * xs_udp_write_space - callback invoked when socket buffer space
1014  *                             becomes available
1015  * @sk: socket whose state has changed
1016  *
1017  * Called when more output buffer space is available for this socket.
1018  * We try not to wake our writers until they can make "significant"
1019  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1020  * with a bunch of small requests.
1021  */
1022 static void xs_udp_write_space(struct sock *sk)
1023 {
1024 	read_lock(&sk->sk_callback_lock);
1025 
1026 	/* from net/core/sock.c:sock_def_write_space */
1027 	if (sock_writeable(sk)) {
1028 		struct socket *sock;
1029 		struct rpc_xprt *xprt;
1030 
1031 		if (unlikely(!(sock = sk->sk_socket)))
1032 			goto out;
1033 		if (unlikely(!(xprt = xprt_from_sock(sk))))
1034 			goto out;
1035 		if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
1036 			goto out;
1037 
1038 		xprt_write_space(xprt);
1039 	}
1040 
1041  out:
1042 	read_unlock(&sk->sk_callback_lock);
1043 }
1044 
1045 /**
1046  * xs_tcp_write_space - callback invoked when socket buffer space
1047  *                             becomes available
1048  * @sk: socket whose state has changed
1049  *
1050  * Called when more output buffer space is available for this socket.
1051  * We try not to wake our writers until they can make "significant"
1052  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1053  * with a bunch of small requests.
1054  */
1055 static void xs_tcp_write_space(struct sock *sk)
1056 {
1057 	read_lock(&sk->sk_callback_lock);
1058 
1059 	/* from net/core/stream.c:sk_stream_write_space */
1060 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
1061 		struct socket *sock;
1062 		struct rpc_xprt *xprt;
1063 
1064 		if (unlikely(!(sock = sk->sk_socket)))
1065 			goto out;
1066 		if (unlikely(!(xprt = xprt_from_sock(sk))))
1067 			goto out;
1068 		if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
1069 			goto out;
1070 
1071 		xprt_write_space(xprt);
1072 	}
1073 
1074  out:
1075 	read_unlock(&sk->sk_callback_lock);
1076 }
1077 
1078 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1079 {
1080 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1081 	struct sock *sk = transport->inet;
1082 
1083 	if (transport->rcvsize) {
1084 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1085 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1086 	}
1087 	if (transport->sndsize) {
1088 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1089 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1090 		sk->sk_write_space(sk);
1091 	}
1092 }
1093 
1094 /**
1095  * xs_udp_set_buffer_size - set send and receive limits
1096  * @xprt: generic transport
1097  * @sndsize: requested size of send buffer, in bytes
1098  * @rcvsize: requested size of receive buffer, in bytes
1099  *
1100  * Set socket send and receive buffer size limits.
1101  */
1102 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1103 {
1104 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1105 
1106 	transport->sndsize = 0;
1107 	if (sndsize)
1108 		transport->sndsize = sndsize + 1024;
1109 	transport->rcvsize = 0;
1110 	if (rcvsize)
1111 		transport->rcvsize = rcvsize + 1024;
1112 
1113 	xs_udp_do_set_buffer_size(xprt);
1114 }
1115 
1116 /**
1117  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1118  * @task: task that timed out
1119  *
1120  * Adjust the congestion window after a retransmit timeout has occurred.
1121  */
1122 static void xs_udp_timer(struct rpc_task *task)
1123 {
1124 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1125 }
1126 
1127 static unsigned short xs_get_random_port(void)
1128 {
1129 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1130 	unsigned short rand = (unsigned short) net_random() % range;
1131 	return rand + xprt_min_resvport;
1132 }
1133 
1134 /**
1135  * xs_set_port - reset the port number in the remote endpoint address
1136  * @xprt: generic transport
1137  * @port: new port number
1138  *
1139  */
1140 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1141 {
1142 	struct sockaddr_in *sap = (struct sockaddr_in *) &xprt->addr;
1143 
1144 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1145 
1146 	sap->sin_port = htons(port);
1147 }
1148 
1149 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1150 {
1151 	struct sockaddr_in myaddr = {
1152 		.sin_family = AF_INET,
1153 	};
1154 	struct sockaddr_in *sa;
1155 	int err;
1156 	unsigned short port = transport->port;
1157 
1158 	if (!transport->xprt.resvport)
1159 		port = 0;
1160 	sa = (struct sockaddr_in *)&transport->addr;
1161 	myaddr.sin_addr = sa->sin_addr;
1162 	do {
1163 		myaddr.sin_port = htons(port);
1164 		err = kernel_bind(sock, (struct sockaddr *) &myaddr,
1165 						sizeof(myaddr));
1166 		if (!transport->xprt.resvport)
1167 			break;
1168 		if (err == 0) {
1169 			transport->port = port;
1170 			break;
1171 		}
1172 		if (port <= xprt_min_resvport)
1173 			port = xprt_max_resvport;
1174 		else
1175 			port--;
1176 	} while (err == -EADDRINUSE && port != transport->port);
1177 	dprintk("RPC:       xs_bind "NIPQUAD_FMT":%u: %s (%d)\n",
1178 		NIPQUAD(myaddr.sin_addr), port, err ? "failed" : "ok", err);
1179 	return err;
1180 }
1181 
1182 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1183 static struct lock_class_key xs_key[2];
1184 static struct lock_class_key xs_slock_key[2];
1185 
1186 static inline void xs_reclassify_socket(struct socket *sock)
1187 {
1188 	struct sock *sk = sock->sk;
1189 	BUG_ON(sock_owned_by_user(sk));
1190 	switch (sk->sk_family) {
1191 	case AF_INET:
1192 		sock_lock_init_class_and_name(sk, "slock-AF_INET-NFS",
1193 			&xs_slock_key[0], "sk_lock-AF_INET-NFS", &xs_key[0]);
1194 		break;
1195 
1196 	case AF_INET6:
1197 		sock_lock_init_class_and_name(sk, "slock-AF_INET6-NFS",
1198 			&xs_slock_key[1], "sk_lock-AF_INET6-NFS", &xs_key[1]);
1199 		break;
1200 
1201 	default:
1202 		BUG();
1203 	}
1204 }
1205 #else
1206 static inline void xs_reclassify_socket(struct socket *sock)
1207 {
1208 }
1209 #endif
1210 
1211 /**
1212  * xs_udp_connect_worker - set up a UDP socket
1213  * @work: RPC transport to connect
1214  *
1215  * Invoked by a work queue tasklet.
1216  */
1217 static void xs_udp_connect_worker(struct work_struct *work)
1218 {
1219 	struct sock_xprt *transport =
1220 		container_of(work, struct sock_xprt, connect_worker.work);
1221 	struct rpc_xprt *xprt = &transport->xprt;
1222 	struct socket *sock = transport->sock;
1223 	int err, status = -EIO;
1224 
1225 	if (xprt->shutdown || !xprt_bound(xprt))
1226 		goto out;
1227 
1228 	/* Start by resetting any existing state */
1229 	xs_close(xprt);
1230 
1231 	if ((err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock)) < 0) {
1232 		dprintk("RPC:       can't create UDP transport socket (%d).\n", -err);
1233 		goto out;
1234 	}
1235 	xs_reclassify_socket(sock);
1236 
1237 	if (xs_bind(transport, sock)) {
1238 		sock_release(sock);
1239 		goto out;
1240 	}
1241 
1242 	dprintk("RPC:       worker connecting xprt %p to address: %s\n",
1243 			xprt, xprt->address_strings[RPC_DISPLAY_ALL]);
1244 
1245 	if (!transport->inet) {
1246 		struct sock *sk = sock->sk;
1247 
1248 		write_lock_bh(&sk->sk_callback_lock);
1249 
1250 		sk->sk_user_data = xprt;
1251 		transport->old_data_ready = sk->sk_data_ready;
1252 		transport->old_state_change = sk->sk_state_change;
1253 		transport->old_write_space = sk->sk_write_space;
1254 		sk->sk_data_ready = xs_udp_data_ready;
1255 		sk->sk_write_space = xs_udp_write_space;
1256 		sk->sk_no_check = UDP_CSUM_NORCV;
1257 		sk->sk_allocation = GFP_ATOMIC;
1258 
1259 		xprt_set_connected(xprt);
1260 
1261 		/* Reset to new socket */
1262 		transport->sock = sock;
1263 		transport->inet = sk;
1264 
1265 		write_unlock_bh(&sk->sk_callback_lock);
1266 	}
1267 	xs_udp_do_set_buffer_size(xprt);
1268 	status = 0;
1269 out:
1270 	xprt_wake_pending_tasks(xprt, status);
1271 	xprt_clear_connecting(xprt);
1272 }
1273 
1274 /*
1275  * We need to preserve the port number so the reply cache on the server can
1276  * find our cached RPC replies when we get around to reconnecting.
1277  */
1278 static void xs_tcp_reuse_connection(struct rpc_xprt *xprt)
1279 {
1280 	int result;
1281 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1282 	struct sockaddr any;
1283 
1284 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", xprt);
1285 
1286 	/*
1287 	 * Disconnect the transport socket by doing a connect operation
1288 	 * with AF_UNSPEC.  This should return immediately...
1289 	 */
1290 	memset(&any, 0, sizeof(any));
1291 	any.sa_family = AF_UNSPEC;
1292 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
1293 	if (result)
1294 		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
1295 				result);
1296 }
1297 
1298 /**
1299  * xs_tcp_connect_worker - connect a TCP socket to a remote endpoint
1300  * @work: RPC transport to connect
1301  *
1302  * Invoked by a work queue tasklet.
1303  */
1304 static void xs_tcp_connect_worker(struct work_struct *work)
1305 {
1306 	struct sock_xprt *transport =
1307 		container_of(work, struct sock_xprt, connect_worker.work);
1308 	struct rpc_xprt *xprt = &transport->xprt;
1309 	struct socket *sock = transport->sock;
1310 	int err, status = -EIO;
1311 
1312 	if (xprt->shutdown || !xprt_bound(xprt))
1313 		goto out;
1314 
1315 	if (!sock) {
1316 		/* start from scratch */
1317 		if ((err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) {
1318 			dprintk("RPC:       can't create TCP transport "
1319 					"socket (%d).\n", -err);
1320 			goto out;
1321 		}
1322 		xs_reclassify_socket(sock);
1323 
1324 		if (xs_bind(transport, sock)) {
1325 			sock_release(sock);
1326 			goto out;
1327 		}
1328 	} else
1329 		/* "close" the socket, preserving the local port */
1330 		xs_tcp_reuse_connection(xprt);
1331 
1332 	dprintk("RPC:       worker connecting xprt %p to address: %s\n",
1333 			xprt, xprt->address_strings[RPC_DISPLAY_ALL]);
1334 
1335 	if (!transport->inet) {
1336 		struct sock *sk = sock->sk;
1337 
1338 		write_lock_bh(&sk->sk_callback_lock);
1339 
1340 		sk->sk_user_data = xprt;
1341 		transport->old_data_ready = sk->sk_data_ready;
1342 		transport->old_state_change = sk->sk_state_change;
1343 		transport->old_write_space = sk->sk_write_space;
1344 		sk->sk_data_ready = xs_tcp_data_ready;
1345 		sk->sk_state_change = xs_tcp_state_change;
1346 		sk->sk_write_space = xs_tcp_write_space;
1347 		sk->sk_allocation = GFP_ATOMIC;
1348 
1349 		/* socket options */
1350 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1351 		sock_reset_flag(sk, SOCK_LINGER);
1352 		tcp_sk(sk)->linger2 = 0;
1353 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1354 
1355 		xprt_clear_connected(xprt);
1356 
1357 		/* Reset to new socket */
1358 		transport->sock = sock;
1359 		transport->inet = sk;
1360 
1361 		write_unlock_bh(&sk->sk_callback_lock);
1362 	}
1363 
1364 	/* Tell the socket layer to start connecting... */
1365 	xprt->stat.connect_count++;
1366 	xprt->stat.connect_start = jiffies;
1367 	status = kernel_connect(sock, (struct sockaddr *) &xprt->addr,
1368 			xprt->addrlen, O_NONBLOCK);
1369 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
1370 			xprt, -status, xprt_connected(xprt),
1371 			sock->sk->sk_state);
1372 	if (status < 0) {
1373 		switch (status) {
1374 			case -EINPROGRESS:
1375 			case -EALREADY:
1376 				goto out_clear;
1377 			case -ECONNREFUSED:
1378 			case -ECONNRESET:
1379 				/* retry with existing socket, after a delay */
1380 				break;
1381 			default:
1382 				/* get rid of existing socket, and retry */
1383 				xs_close(xprt);
1384 				break;
1385 		}
1386 	}
1387 out:
1388 	xprt_wake_pending_tasks(xprt, status);
1389 out_clear:
1390 	xprt_clear_connecting(xprt);
1391 }
1392 
1393 /**
1394  * xs_connect - connect a socket to a remote endpoint
1395  * @task: address of RPC task that manages state of connect request
1396  *
1397  * TCP: If the remote end dropped the connection, delay reconnecting.
1398  *
1399  * UDP socket connects are synchronous, but we use a work queue anyway
1400  * to guarantee that even unprivileged user processes can set up a
1401  * socket on a privileged port.
1402  *
1403  * If a UDP socket connect fails, the delay behavior here prevents
1404  * retry floods (hard mounts).
1405  */
1406 static void xs_connect(struct rpc_task *task)
1407 {
1408 	struct rpc_xprt *xprt = task->tk_xprt;
1409 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1410 
1411 	if (xprt_test_and_set_connecting(xprt))
1412 		return;
1413 
1414 	if (transport->sock != NULL) {
1415 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
1416 				"seconds\n",
1417 				xprt, xprt->reestablish_timeout / HZ);
1418 		queue_delayed_work(rpciod_workqueue,
1419 				   &transport->connect_worker,
1420 				   xprt->reestablish_timeout);
1421 		xprt->reestablish_timeout <<= 1;
1422 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
1423 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
1424 	} else {
1425 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
1426 		queue_delayed_work(rpciod_workqueue,
1427 				   &transport->connect_worker, 0);
1428 	}
1429 }
1430 
1431 /**
1432  * xs_udp_print_stats - display UDP socket-specifc stats
1433  * @xprt: rpc_xprt struct containing statistics
1434  * @seq: output file
1435  *
1436  */
1437 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1438 {
1439 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1440 
1441 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %Lu %Lu\n",
1442 			transport->port,
1443 			xprt->stat.bind_count,
1444 			xprt->stat.sends,
1445 			xprt->stat.recvs,
1446 			xprt->stat.bad_xids,
1447 			xprt->stat.req_u,
1448 			xprt->stat.bklog_u);
1449 }
1450 
1451 /**
1452  * xs_tcp_print_stats - display TCP socket-specifc stats
1453  * @xprt: rpc_xprt struct containing statistics
1454  * @seq: output file
1455  *
1456  */
1457 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
1458 {
1459 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1460 	long idle_time = 0;
1461 
1462 	if (xprt_connected(xprt))
1463 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
1464 
1465 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu %Lu %Lu\n",
1466 			transport->port,
1467 			xprt->stat.bind_count,
1468 			xprt->stat.connect_count,
1469 			xprt->stat.connect_time,
1470 			idle_time,
1471 			xprt->stat.sends,
1472 			xprt->stat.recvs,
1473 			xprt->stat.bad_xids,
1474 			xprt->stat.req_u,
1475 			xprt->stat.bklog_u);
1476 }
1477 
1478 static struct rpc_xprt_ops xs_udp_ops = {
1479 	.set_buffer_size	= xs_udp_set_buffer_size,
1480 	.reserve_xprt		= xprt_reserve_xprt_cong,
1481 	.release_xprt		= xprt_release_xprt_cong,
1482 	.rpcbind		= rpcb_getport_async,
1483 	.set_port		= xs_set_port,
1484 	.connect		= xs_connect,
1485 	.buf_alloc		= rpc_malloc,
1486 	.buf_free		= rpc_free,
1487 	.send_request		= xs_udp_send_request,
1488 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
1489 	.timer			= xs_udp_timer,
1490 	.release_request	= xprt_release_rqst_cong,
1491 	.close			= xs_close,
1492 	.destroy		= xs_destroy,
1493 	.print_stats		= xs_udp_print_stats,
1494 };
1495 
1496 static struct rpc_xprt_ops xs_tcp_ops = {
1497 	.reserve_xprt		= xprt_reserve_xprt,
1498 	.release_xprt		= xs_tcp_release_xprt,
1499 	.rpcbind		= rpcb_getport_async,
1500 	.set_port		= xs_set_port,
1501 	.connect		= xs_connect,
1502 	.buf_alloc		= rpc_malloc,
1503 	.buf_free		= rpc_free,
1504 	.send_request		= xs_tcp_send_request,
1505 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
1506 	.close			= xs_close,
1507 	.destroy		= xs_destroy,
1508 	.print_stats		= xs_tcp_print_stats,
1509 };
1510 
1511 static struct rpc_xprt *xs_setup_xprt(struct rpc_xprtsock_create *args, unsigned int slot_table_size)
1512 {
1513 	struct rpc_xprt *xprt;
1514 	struct sock_xprt *new;
1515 
1516 	if (args->addrlen > sizeof(xprt->addr)) {
1517 		dprintk("RPC:       xs_setup_xprt: address too large\n");
1518 		return ERR_PTR(-EBADF);
1519 	}
1520 
1521 	new = kzalloc(sizeof(*new), GFP_KERNEL);
1522 	if (new == NULL) {
1523 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
1524 				"rpc_xprt\n");
1525 		return ERR_PTR(-ENOMEM);
1526 	}
1527 	xprt = &new->xprt;
1528 
1529 	xprt->max_reqs = slot_table_size;
1530 	xprt->slot = kcalloc(xprt->max_reqs, sizeof(struct rpc_rqst), GFP_KERNEL);
1531 	if (xprt->slot == NULL) {
1532 		kfree(xprt);
1533 		dprintk("RPC:       xs_setup_xprt: couldn't allocate slot "
1534 				"table\n");
1535 		return ERR_PTR(-ENOMEM);
1536 	}
1537 
1538 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
1539 	xprt->addrlen = args->addrlen;
1540 	if (args->srcaddr)
1541 		memcpy(&new->addr, args->srcaddr, args->addrlen);
1542 	new->port = xs_get_random_port();
1543 
1544 	return xprt;
1545 }
1546 
1547 /**
1548  * xs_setup_udp - Set up transport to use a UDP socket
1549  * @args: rpc transport creation arguments
1550  *
1551  */
1552 struct rpc_xprt *xs_setup_udp(struct rpc_xprtsock_create *args)
1553 {
1554 	struct rpc_xprt *xprt;
1555 	struct sock_xprt *transport;
1556 
1557 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries);
1558 	if (IS_ERR(xprt))
1559 		return xprt;
1560 	transport = container_of(xprt, struct sock_xprt, xprt);
1561 
1562 	if (ntohs(((struct sockaddr_in *)args->dstaddr)->sin_port) != 0)
1563 		xprt_set_bound(xprt);
1564 
1565 	xprt->prot = IPPROTO_UDP;
1566 	xprt->tsh_size = 0;
1567 	/* XXX: header size can vary due to auth type, IPv6, etc. */
1568 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
1569 
1570 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_connect_worker);
1571 	xprt->bind_timeout = XS_BIND_TO;
1572 	xprt->connect_timeout = XS_UDP_CONN_TO;
1573 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
1574 	xprt->idle_timeout = XS_IDLE_DISC_TO;
1575 
1576 	xprt->ops = &xs_udp_ops;
1577 
1578 	if (args->timeout)
1579 		xprt->timeout = *args->timeout;
1580 	else
1581 		xprt_set_timeout(&xprt->timeout, 5, 5 * HZ);
1582 
1583 	xs_format_peer_addresses(xprt);
1584 	dprintk("RPC:       set up transport to address %s\n",
1585 			xprt->address_strings[RPC_DISPLAY_ALL]);
1586 
1587 	return xprt;
1588 }
1589 
1590 /**
1591  * xs_setup_tcp - Set up transport to use a TCP socket
1592  * @args: rpc transport creation arguments
1593  *
1594  */
1595 struct rpc_xprt *xs_setup_tcp(struct rpc_xprtsock_create *args)
1596 {
1597 	struct rpc_xprt *xprt;
1598 	struct sock_xprt *transport;
1599 
1600 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries);
1601 	if (IS_ERR(xprt))
1602 		return xprt;
1603 	transport = container_of(xprt, struct sock_xprt, xprt);
1604 
1605 	if (ntohs(((struct sockaddr_in *)args->dstaddr)->sin_port) != 0)
1606 		xprt_set_bound(xprt);
1607 
1608 	xprt->prot = IPPROTO_TCP;
1609 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
1610 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
1611 
1612 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_connect_worker);
1613 	xprt->bind_timeout = XS_BIND_TO;
1614 	xprt->connect_timeout = XS_TCP_CONN_TO;
1615 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1616 	xprt->idle_timeout = XS_IDLE_DISC_TO;
1617 
1618 	xprt->ops = &xs_tcp_ops;
1619 
1620 	if (args->timeout)
1621 		xprt->timeout = *args->timeout;
1622 	else
1623 		xprt_set_timeout(&xprt->timeout, 2, 60 * HZ);
1624 
1625 	xs_format_peer_addresses(xprt);
1626 	dprintk("RPC:       set up transport to address %s\n",
1627 			xprt->address_strings[RPC_DISPLAY_ALL]);
1628 
1629 	return xprt;
1630 }
1631 
1632 /**
1633  * init_socket_xprt - set up xprtsock's sysctls
1634  *
1635  */
1636 int init_socket_xprt(void)
1637 {
1638 #ifdef RPC_DEBUG
1639 	if (!sunrpc_table_header)
1640 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
1641 #endif
1642 
1643 	return 0;
1644 }
1645 
1646 /**
1647  * cleanup_socket_xprt - remove xprtsock's sysctls
1648  *
1649  */
1650 void cleanup_socket_xprt(void)
1651 {
1652 #ifdef RPC_DEBUG
1653 	if (sunrpc_table_header) {
1654 		unregister_sysctl_table(sunrpc_table_header);
1655 		sunrpc_table_header = NULL;
1656 	}
1657 #endif
1658 }
1659