xref: /linux/net/sunrpc/xprtsock.c (revision 61d0b5a4b2777dcf5daef245e212b3c1fa8091ca)
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/string.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/capability.h>
26 #include <linux/pagemap.h>
27 #include <linux/errno.h>
28 #include <linux/socket.h>
29 #include <linux/in.h>
30 #include <linux/net.h>
31 #include <linux/mm.h>
32 #include <linux/un.h>
33 #include <linux/udp.h>
34 #include <linux/tcp.h>
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/addr.h>
37 #include <linux/sunrpc/sched.h>
38 #include <linux/sunrpc/svcsock.h>
39 #include <linux/sunrpc/xprtsock.h>
40 #include <linux/file.h>
41 #ifdef CONFIG_SUNRPC_BACKCHANNEL
42 #include <linux/sunrpc/bc_xprt.h>
43 #endif
44 
45 #include <net/sock.h>
46 #include <net/checksum.h>
47 #include <net/udp.h>
48 #include <net/tcp.h>
49 
50 #include "sunrpc.h"
51 
52 static void xs_close(struct rpc_xprt *xprt);
53 
54 /*
55  * xprtsock tunables
56  */
57 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
58 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
59 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
60 
61 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
62 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
63 
64 #define XS_TCP_LINGER_TO	(15U * HZ)
65 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
66 
67 /*
68  * We can register our own files under /proc/sys/sunrpc by
69  * calling register_sysctl_table() again.  The files in that
70  * directory become the union of all files registered there.
71  *
72  * We simply need to make sure that we don't collide with
73  * someone else's file names!
74  */
75 
76 #ifdef RPC_DEBUG
77 
78 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
79 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
80 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
81 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
82 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
83 
84 static struct ctl_table_header *sunrpc_table_header;
85 
86 /*
87  * FIXME: changing the UDP slot table size should also resize the UDP
88  *        socket buffers for existing UDP transports
89  */
90 static ctl_table xs_tunables_table[] = {
91 	{
92 		.procname	= "udp_slot_table_entries",
93 		.data		= &xprt_udp_slot_table_entries,
94 		.maxlen		= sizeof(unsigned int),
95 		.mode		= 0644,
96 		.proc_handler	= proc_dointvec_minmax,
97 		.extra1		= &min_slot_table_size,
98 		.extra2		= &max_slot_table_size
99 	},
100 	{
101 		.procname	= "tcp_slot_table_entries",
102 		.data		= &xprt_tcp_slot_table_entries,
103 		.maxlen		= sizeof(unsigned int),
104 		.mode		= 0644,
105 		.proc_handler	= proc_dointvec_minmax,
106 		.extra1		= &min_slot_table_size,
107 		.extra2		= &max_slot_table_size
108 	},
109 	{
110 		.procname	= "tcp_max_slot_table_entries",
111 		.data		= &xprt_max_tcp_slot_table_entries,
112 		.maxlen		= sizeof(unsigned int),
113 		.mode		= 0644,
114 		.proc_handler	= proc_dointvec_minmax,
115 		.extra1		= &min_slot_table_size,
116 		.extra2		= &max_tcp_slot_table_limit
117 	},
118 	{
119 		.procname	= "min_resvport",
120 		.data		= &xprt_min_resvport,
121 		.maxlen		= sizeof(unsigned int),
122 		.mode		= 0644,
123 		.proc_handler	= proc_dointvec_minmax,
124 		.extra1		= &xprt_min_resvport_limit,
125 		.extra2		= &xprt_max_resvport_limit
126 	},
127 	{
128 		.procname	= "max_resvport",
129 		.data		= &xprt_max_resvport,
130 		.maxlen		= sizeof(unsigned int),
131 		.mode		= 0644,
132 		.proc_handler	= proc_dointvec_minmax,
133 		.extra1		= &xprt_min_resvport_limit,
134 		.extra2		= &xprt_max_resvport_limit
135 	},
136 	{
137 		.procname	= "tcp_fin_timeout",
138 		.data		= &xs_tcp_fin_timeout,
139 		.maxlen		= sizeof(xs_tcp_fin_timeout),
140 		.mode		= 0644,
141 		.proc_handler	= proc_dointvec_jiffies,
142 	},
143 	{ },
144 };
145 
146 static ctl_table sunrpc_table[] = {
147 	{
148 		.procname	= "sunrpc",
149 		.mode		= 0555,
150 		.child		= xs_tunables_table
151 	},
152 	{ },
153 };
154 
155 #endif
156 
157 /*
158  * Wait duration for a reply from the RPC portmapper.
159  */
160 #define XS_BIND_TO		(60U * HZ)
161 
162 /*
163  * Delay if a UDP socket connect error occurs.  This is most likely some
164  * kind of resource problem on the local host.
165  */
166 #define XS_UDP_REEST_TO		(2U * HZ)
167 
168 /*
169  * The reestablish timeout allows clients to delay for a bit before attempting
170  * to reconnect to a server that just dropped our connection.
171  *
172  * We implement an exponential backoff when trying to reestablish a TCP
173  * transport connection with the server.  Some servers like to drop a TCP
174  * connection when they are overworked, so we start with a short timeout and
175  * increase over time if the server is down or not responding.
176  */
177 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
178 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
179 
180 /*
181  * TCP idle timeout; client drops the transport socket if it is idle
182  * for this long.  Note that we also timeout UDP sockets to prevent
183  * holding port numbers when there is no RPC traffic.
184  */
185 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
186 
187 #ifdef RPC_DEBUG
188 # undef  RPC_DEBUG_DATA
189 # define RPCDBG_FACILITY	RPCDBG_TRANS
190 #endif
191 
192 #ifdef RPC_DEBUG_DATA
193 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
194 {
195 	u8 *buf = (u8 *) packet;
196 	int j;
197 
198 	dprintk("RPC:       %s\n", msg);
199 	for (j = 0; j < count && j < 128; j += 4) {
200 		if (!(j & 31)) {
201 			if (j)
202 				dprintk("\n");
203 			dprintk("0x%04x ", j);
204 		}
205 		dprintk("%02x%02x%02x%02x ",
206 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
207 	}
208 	dprintk("\n");
209 }
210 #else
211 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
212 {
213 	/* NOP */
214 }
215 #endif
216 
217 struct sock_xprt {
218 	struct rpc_xprt		xprt;
219 
220 	/*
221 	 * Network layer
222 	 */
223 	struct socket *		sock;
224 	struct sock *		inet;
225 
226 	/*
227 	 * State of TCP reply receive
228 	 */
229 	__be32			tcp_fraghdr,
230 				tcp_xid,
231 				tcp_calldir;
232 
233 	u32			tcp_offset,
234 				tcp_reclen;
235 
236 	unsigned long		tcp_copied,
237 				tcp_flags;
238 
239 	/*
240 	 * Connection of transports
241 	 */
242 	struct delayed_work	connect_worker;
243 	struct sockaddr_storage	srcaddr;
244 	unsigned short		srcport;
245 
246 	/*
247 	 * UDP socket buffer size parameters
248 	 */
249 	size_t			rcvsize,
250 				sndsize;
251 
252 	/*
253 	 * Saved socket callback addresses
254 	 */
255 	void			(*old_data_ready)(struct sock *, int);
256 	void			(*old_state_change)(struct sock *);
257 	void			(*old_write_space)(struct sock *);
258 };
259 
260 /*
261  * TCP receive state flags
262  */
263 #define TCP_RCV_LAST_FRAG	(1UL << 0)
264 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
265 #define TCP_RCV_COPY_XID	(1UL << 2)
266 #define TCP_RCV_COPY_DATA	(1UL << 3)
267 #define TCP_RCV_READ_CALLDIR	(1UL << 4)
268 #define TCP_RCV_COPY_CALLDIR	(1UL << 5)
269 
270 /*
271  * TCP RPC flags
272  */
273 #define TCP_RPC_REPLY		(1UL << 6)
274 
275 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
276 {
277 	return (struct sockaddr *) &xprt->addr;
278 }
279 
280 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
281 {
282 	return (struct sockaddr_un *) &xprt->addr;
283 }
284 
285 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
286 {
287 	return (struct sockaddr_in *) &xprt->addr;
288 }
289 
290 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
291 {
292 	return (struct sockaddr_in6 *) &xprt->addr;
293 }
294 
295 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
296 {
297 	struct sockaddr *sap = xs_addr(xprt);
298 	struct sockaddr_in6 *sin6;
299 	struct sockaddr_in *sin;
300 	struct sockaddr_un *sun;
301 	char buf[128];
302 
303 	switch (sap->sa_family) {
304 	case AF_LOCAL:
305 		sun = xs_addr_un(xprt);
306 		strlcpy(buf, sun->sun_path, sizeof(buf));
307 		xprt->address_strings[RPC_DISPLAY_ADDR] =
308 						kstrdup(buf, GFP_KERNEL);
309 		break;
310 	case AF_INET:
311 		(void)rpc_ntop(sap, buf, sizeof(buf));
312 		xprt->address_strings[RPC_DISPLAY_ADDR] =
313 						kstrdup(buf, GFP_KERNEL);
314 		sin = xs_addr_in(xprt);
315 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
316 		break;
317 	case AF_INET6:
318 		(void)rpc_ntop(sap, buf, sizeof(buf));
319 		xprt->address_strings[RPC_DISPLAY_ADDR] =
320 						kstrdup(buf, GFP_KERNEL);
321 		sin6 = xs_addr_in6(xprt);
322 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
323 		break;
324 	default:
325 		BUG();
326 	}
327 
328 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
329 }
330 
331 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
332 {
333 	struct sockaddr *sap = xs_addr(xprt);
334 	char buf[128];
335 
336 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
337 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
338 
339 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
340 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
341 }
342 
343 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
344 				     const char *protocol,
345 				     const char *netid)
346 {
347 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
348 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
349 	xs_format_common_peer_addresses(xprt);
350 	xs_format_common_peer_ports(xprt);
351 }
352 
353 static void xs_update_peer_port(struct rpc_xprt *xprt)
354 {
355 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
356 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
357 
358 	xs_format_common_peer_ports(xprt);
359 }
360 
361 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
362 {
363 	unsigned int i;
364 
365 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
366 		switch (i) {
367 		case RPC_DISPLAY_PROTO:
368 		case RPC_DISPLAY_NETID:
369 			continue;
370 		default:
371 			kfree(xprt->address_strings[i]);
372 		}
373 }
374 
375 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
376 
377 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
378 {
379 	struct msghdr msg = {
380 		.msg_name	= addr,
381 		.msg_namelen	= addrlen,
382 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
383 	};
384 	struct kvec iov = {
385 		.iov_base	= vec->iov_base + base,
386 		.iov_len	= vec->iov_len - base,
387 	};
388 
389 	if (iov.iov_len != 0)
390 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
391 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
392 }
393 
394 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
395 {
396 	struct page **ppage;
397 	unsigned int remainder;
398 	int err, sent = 0;
399 
400 	remainder = xdr->page_len - base;
401 	base += xdr->page_base;
402 	ppage = xdr->pages + (base >> PAGE_SHIFT);
403 	base &= ~PAGE_MASK;
404 	for(;;) {
405 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
406 		int flags = XS_SENDMSG_FLAGS;
407 
408 		remainder -= len;
409 		if (remainder != 0 || more)
410 			flags |= MSG_MORE;
411 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
412 		if (remainder == 0 || err != len)
413 			break;
414 		sent += err;
415 		ppage++;
416 		base = 0;
417 	}
418 	if (sent == 0)
419 		return err;
420 	if (err > 0)
421 		sent += err;
422 	return sent;
423 }
424 
425 /**
426  * xs_sendpages - write pages directly to a socket
427  * @sock: socket to send on
428  * @addr: UDP only -- address of destination
429  * @addrlen: UDP only -- length of destination address
430  * @xdr: buffer containing this request
431  * @base: starting position in the buffer
432  *
433  */
434 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
435 {
436 	unsigned int remainder = xdr->len - base;
437 	int err, sent = 0;
438 
439 	if (unlikely(!sock))
440 		return -ENOTSOCK;
441 
442 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
443 	if (base != 0) {
444 		addr = NULL;
445 		addrlen = 0;
446 	}
447 
448 	if (base < xdr->head[0].iov_len || addr != NULL) {
449 		unsigned int len = xdr->head[0].iov_len - base;
450 		remainder -= len;
451 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
452 		if (remainder == 0 || err != len)
453 			goto out;
454 		sent += err;
455 		base = 0;
456 	} else
457 		base -= xdr->head[0].iov_len;
458 
459 	if (base < xdr->page_len) {
460 		unsigned int len = xdr->page_len - base;
461 		remainder -= len;
462 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
463 		if (remainder == 0 || err != len)
464 			goto out;
465 		sent += err;
466 		base = 0;
467 	} else
468 		base -= xdr->page_len;
469 
470 	if (base >= xdr->tail[0].iov_len)
471 		return sent;
472 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
473 out:
474 	if (sent == 0)
475 		return err;
476 	if (err > 0)
477 		sent += err;
478 	return sent;
479 }
480 
481 static void xs_nospace_callback(struct rpc_task *task)
482 {
483 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
484 
485 	transport->inet->sk_write_pending--;
486 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
487 }
488 
489 /**
490  * xs_nospace - place task on wait queue if transmit was incomplete
491  * @task: task to put to sleep
492  *
493  */
494 static int xs_nospace(struct rpc_task *task)
495 {
496 	struct rpc_rqst *req = task->tk_rqstp;
497 	struct rpc_xprt *xprt = req->rq_xprt;
498 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
499 	int ret = -EAGAIN;
500 
501 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
502 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
503 			req->rq_slen);
504 
505 	/* Protect against races with write_space */
506 	spin_lock_bh(&xprt->transport_lock);
507 
508 	/* Don't race with disconnect */
509 	if (xprt_connected(xprt)) {
510 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
511 			/*
512 			 * Notify TCP that we're limited by the application
513 			 * window size
514 			 */
515 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
516 			transport->inet->sk_write_pending++;
517 			/* ...and wait for more buffer space */
518 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
519 		}
520 	} else {
521 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
522 		ret = -ENOTCONN;
523 	}
524 
525 	spin_unlock_bh(&xprt->transport_lock);
526 	return ret;
527 }
528 
529 /*
530  * Construct a stream transport record marker in @buf.
531  */
532 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
533 {
534 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
535 	rpc_fraghdr *base = buf->head[0].iov_base;
536 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
537 }
538 
539 /**
540  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
541  * @task: RPC task that manages the state of an RPC request
542  *
543  * Return values:
544  *        0:	The request has been sent
545  *   EAGAIN:	The socket was blocked, please call again later to
546  *		complete the request
547  * ENOTCONN:	Caller needs to invoke connect logic then call again
548  *    other:	Some other error occured, the request was not sent
549  */
550 static int xs_local_send_request(struct rpc_task *task)
551 {
552 	struct rpc_rqst *req = task->tk_rqstp;
553 	struct rpc_xprt *xprt = req->rq_xprt;
554 	struct sock_xprt *transport =
555 				container_of(xprt, struct sock_xprt, xprt);
556 	struct xdr_buf *xdr = &req->rq_snd_buf;
557 	int status;
558 
559 	xs_encode_stream_record_marker(&req->rq_snd_buf);
560 
561 	xs_pktdump("packet data:",
562 			req->rq_svec->iov_base, req->rq_svec->iov_len);
563 
564 	status = xs_sendpages(transport->sock, NULL, 0,
565 						xdr, req->rq_bytes_sent);
566 	dprintk("RPC:       %s(%u) = %d\n",
567 			__func__, xdr->len - req->rq_bytes_sent, status);
568 	if (likely(status >= 0)) {
569 		req->rq_bytes_sent += status;
570 		req->rq_xmit_bytes_sent += status;
571 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
572 			req->rq_bytes_sent = 0;
573 			return 0;
574 		}
575 		status = -EAGAIN;
576 	}
577 
578 	switch (status) {
579 	case -EAGAIN:
580 		status = xs_nospace(task);
581 		break;
582 	default:
583 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
584 			-status);
585 	case -EPIPE:
586 		xs_close(xprt);
587 		status = -ENOTCONN;
588 	}
589 
590 	return status;
591 }
592 
593 /**
594  * xs_udp_send_request - write an RPC request to a UDP socket
595  * @task: address of RPC task that manages the state of an RPC request
596  *
597  * Return values:
598  *        0:	The request has been sent
599  *   EAGAIN:	The socket was blocked, please call again later to
600  *		complete the request
601  * ENOTCONN:	Caller needs to invoke connect logic then call again
602  *    other:	Some other error occurred, the request was not sent
603  */
604 static int xs_udp_send_request(struct rpc_task *task)
605 {
606 	struct rpc_rqst *req = task->tk_rqstp;
607 	struct rpc_xprt *xprt = req->rq_xprt;
608 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
609 	struct xdr_buf *xdr = &req->rq_snd_buf;
610 	int status;
611 
612 	xs_pktdump("packet data:",
613 				req->rq_svec->iov_base,
614 				req->rq_svec->iov_len);
615 
616 	if (!xprt_bound(xprt))
617 		return -ENOTCONN;
618 	status = xs_sendpages(transport->sock,
619 			      xs_addr(xprt),
620 			      xprt->addrlen, xdr,
621 			      req->rq_bytes_sent);
622 
623 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
624 			xdr->len - req->rq_bytes_sent, status);
625 
626 	if (status >= 0) {
627 		req->rq_xmit_bytes_sent += status;
628 		if (status >= req->rq_slen)
629 			return 0;
630 		/* Still some bytes left; set up for a retry later. */
631 		status = -EAGAIN;
632 	}
633 
634 	switch (status) {
635 	case -ENOTSOCK:
636 		status = -ENOTCONN;
637 		/* Should we call xs_close() here? */
638 		break;
639 	case -EAGAIN:
640 		status = xs_nospace(task);
641 		break;
642 	default:
643 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
644 			-status);
645 	case -ENETUNREACH:
646 	case -EPIPE:
647 	case -ECONNREFUSED:
648 		/* When the server has died, an ICMP port unreachable message
649 		 * prompts ECONNREFUSED. */
650 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
651 	}
652 
653 	return status;
654 }
655 
656 /**
657  * xs_tcp_shutdown - gracefully shut down a TCP socket
658  * @xprt: transport
659  *
660  * Initiates a graceful shutdown of the TCP socket by calling the
661  * equivalent of shutdown(SHUT_WR);
662  */
663 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
664 {
665 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
666 	struct socket *sock = transport->sock;
667 
668 	if (sock != NULL)
669 		kernel_sock_shutdown(sock, SHUT_WR);
670 }
671 
672 /**
673  * xs_tcp_send_request - write an RPC request to a TCP socket
674  * @task: address of RPC task that manages the state of an RPC request
675  *
676  * Return values:
677  *        0:	The request has been sent
678  *   EAGAIN:	The socket was blocked, please call again later to
679  *		complete the request
680  * ENOTCONN:	Caller needs to invoke connect logic then call again
681  *    other:	Some other error occurred, the request was not sent
682  *
683  * XXX: In the case of soft timeouts, should we eventually give up
684  *	if sendmsg is not able to make progress?
685  */
686 static int xs_tcp_send_request(struct rpc_task *task)
687 {
688 	struct rpc_rqst *req = task->tk_rqstp;
689 	struct rpc_xprt *xprt = req->rq_xprt;
690 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
691 	struct xdr_buf *xdr = &req->rq_snd_buf;
692 	int status;
693 
694 	xs_encode_stream_record_marker(&req->rq_snd_buf);
695 
696 	xs_pktdump("packet data:",
697 				req->rq_svec->iov_base,
698 				req->rq_svec->iov_len);
699 
700 	/* Continue transmitting the packet/record. We must be careful
701 	 * to cope with writespace callbacks arriving _after_ we have
702 	 * called sendmsg(). */
703 	while (1) {
704 		status = xs_sendpages(transport->sock,
705 					NULL, 0, xdr, req->rq_bytes_sent);
706 
707 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
708 				xdr->len - req->rq_bytes_sent, status);
709 
710 		if (unlikely(status < 0))
711 			break;
712 
713 		/* If we've sent the entire packet, immediately
714 		 * reset the count of bytes sent. */
715 		req->rq_bytes_sent += status;
716 		req->rq_xmit_bytes_sent += status;
717 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
718 			req->rq_bytes_sent = 0;
719 			return 0;
720 		}
721 
722 		if (status != 0)
723 			continue;
724 		status = -EAGAIN;
725 		break;
726 	}
727 
728 	switch (status) {
729 	case -ENOTSOCK:
730 		status = -ENOTCONN;
731 		/* Should we call xs_close() here? */
732 		break;
733 	case -EAGAIN:
734 		status = xs_nospace(task);
735 		break;
736 	default:
737 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
738 			-status);
739 	case -ECONNRESET:
740 		xs_tcp_shutdown(xprt);
741 	case -ECONNREFUSED:
742 	case -ENOTCONN:
743 	case -EPIPE:
744 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
745 	}
746 
747 	return status;
748 }
749 
750 /**
751  * xs_tcp_release_xprt - clean up after a tcp transmission
752  * @xprt: transport
753  * @task: rpc task
754  *
755  * This cleans up if an error causes us to abort the transmission of a request.
756  * In this case, the socket may need to be reset in order to avoid confusing
757  * the server.
758  */
759 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
760 {
761 	struct rpc_rqst *req;
762 
763 	if (task != xprt->snd_task)
764 		return;
765 	if (task == NULL)
766 		goto out_release;
767 	req = task->tk_rqstp;
768 	if (req == NULL)
769 		goto out_release;
770 	if (req->rq_bytes_sent == 0)
771 		goto out_release;
772 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
773 		goto out_release;
774 	set_bit(XPRT_CLOSE_WAIT, &xprt->state);
775 out_release:
776 	xprt_release_xprt(xprt, task);
777 }
778 
779 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
780 {
781 	transport->old_data_ready = sk->sk_data_ready;
782 	transport->old_state_change = sk->sk_state_change;
783 	transport->old_write_space = sk->sk_write_space;
784 }
785 
786 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
787 {
788 	sk->sk_data_ready = transport->old_data_ready;
789 	sk->sk_state_change = transport->old_state_change;
790 	sk->sk_write_space = transport->old_write_space;
791 }
792 
793 static void xs_reset_transport(struct sock_xprt *transport)
794 {
795 	struct socket *sock = transport->sock;
796 	struct sock *sk = transport->inet;
797 
798 	if (sk == NULL)
799 		return;
800 
801 	transport->srcport = 0;
802 
803 	write_lock_bh(&sk->sk_callback_lock);
804 	transport->inet = NULL;
805 	transport->sock = NULL;
806 
807 	sk->sk_user_data = NULL;
808 
809 	xs_restore_old_callbacks(transport, sk);
810 	write_unlock_bh(&sk->sk_callback_lock);
811 
812 	sk->sk_no_check = 0;
813 
814 	sock_release(sock);
815 }
816 
817 /**
818  * xs_close - close a socket
819  * @xprt: transport
820  *
821  * This is used when all requests are complete; ie, no DRC state remains
822  * on the server we want to save.
823  *
824  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
825  * xs_reset_transport() zeroing the socket from underneath a writer.
826  */
827 static void xs_close(struct rpc_xprt *xprt)
828 {
829 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
830 
831 	dprintk("RPC:       xs_close xprt %p\n", xprt);
832 
833 	xs_reset_transport(transport);
834 	xprt->reestablish_timeout = 0;
835 
836 	smp_mb__before_clear_bit();
837 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
838 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
839 	clear_bit(XPRT_CLOSING, &xprt->state);
840 	smp_mb__after_clear_bit();
841 	xprt_disconnect_done(xprt);
842 }
843 
844 static void xs_tcp_close(struct rpc_xprt *xprt)
845 {
846 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
847 		xs_close(xprt);
848 	else
849 		xs_tcp_shutdown(xprt);
850 }
851 
852 /**
853  * xs_destroy - prepare to shutdown a transport
854  * @xprt: doomed transport
855  *
856  */
857 static void xs_destroy(struct rpc_xprt *xprt)
858 {
859 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
860 
861 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
862 
863 	cancel_delayed_work_sync(&transport->connect_worker);
864 
865 	xs_close(xprt);
866 	xs_free_peer_addresses(xprt);
867 	xprt_free(xprt);
868 	module_put(THIS_MODULE);
869 }
870 
871 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
872 {
873 	return (struct rpc_xprt *) sk->sk_user_data;
874 }
875 
876 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
877 {
878 	struct xdr_skb_reader desc = {
879 		.skb		= skb,
880 		.offset		= sizeof(rpc_fraghdr),
881 		.count		= skb->len - sizeof(rpc_fraghdr),
882 	};
883 
884 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
885 		return -1;
886 	if (desc.count)
887 		return -1;
888 	return 0;
889 }
890 
891 /**
892  * xs_local_data_ready - "data ready" callback for AF_LOCAL sockets
893  * @sk: socket with data to read
894  * @len: how much data to read
895  *
896  * Currently this assumes we can read the whole reply in a single gulp.
897  */
898 static void xs_local_data_ready(struct sock *sk, int len)
899 {
900 	struct rpc_task *task;
901 	struct rpc_xprt *xprt;
902 	struct rpc_rqst *rovr;
903 	struct sk_buff *skb;
904 	int err, repsize, copied;
905 	u32 _xid;
906 	__be32 *xp;
907 
908 	read_lock_bh(&sk->sk_callback_lock);
909 	dprintk("RPC:       %s...\n", __func__);
910 	xprt = xprt_from_sock(sk);
911 	if (xprt == NULL)
912 		goto out;
913 
914 	skb = skb_recv_datagram(sk, 0, 1, &err);
915 	if (skb == NULL)
916 		goto out;
917 
918 	repsize = skb->len - sizeof(rpc_fraghdr);
919 	if (repsize < 4) {
920 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
921 		goto dropit;
922 	}
923 
924 	/* Copy the XID from the skb... */
925 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
926 	if (xp == NULL)
927 		goto dropit;
928 
929 	/* Look up and lock the request corresponding to the given XID */
930 	spin_lock(&xprt->transport_lock);
931 	rovr = xprt_lookup_rqst(xprt, *xp);
932 	if (!rovr)
933 		goto out_unlock;
934 	task = rovr->rq_task;
935 
936 	copied = rovr->rq_private_buf.buflen;
937 	if (copied > repsize)
938 		copied = repsize;
939 
940 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
941 		dprintk("RPC:       sk_buff copy failed\n");
942 		goto out_unlock;
943 	}
944 
945 	xprt_complete_rqst(task, copied);
946 
947  out_unlock:
948 	spin_unlock(&xprt->transport_lock);
949  dropit:
950 	skb_free_datagram(sk, skb);
951  out:
952 	read_unlock_bh(&sk->sk_callback_lock);
953 }
954 
955 /**
956  * xs_udp_data_ready - "data ready" callback for UDP sockets
957  * @sk: socket with data to read
958  * @len: how much data to read
959  *
960  */
961 static void xs_udp_data_ready(struct sock *sk, int len)
962 {
963 	struct rpc_task *task;
964 	struct rpc_xprt *xprt;
965 	struct rpc_rqst *rovr;
966 	struct sk_buff *skb;
967 	int err, repsize, copied;
968 	u32 _xid;
969 	__be32 *xp;
970 
971 	read_lock_bh(&sk->sk_callback_lock);
972 	dprintk("RPC:       xs_udp_data_ready...\n");
973 	if (!(xprt = xprt_from_sock(sk)))
974 		goto out;
975 
976 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
977 		goto out;
978 
979 	repsize = skb->len - sizeof(struct udphdr);
980 	if (repsize < 4) {
981 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
982 		goto dropit;
983 	}
984 
985 	/* Copy the XID from the skb... */
986 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
987 				sizeof(_xid), &_xid);
988 	if (xp == NULL)
989 		goto dropit;
990 
991 	/* Look up and lock the request corresponding to the given XID */
992 	spin_lock(&xprt->transport_lock);
993 	rovr = xprt_lookup_rqst(xprt, *xp);
994 	if (!rovr)
995 		goto out_unlock;
996 	task = rovr->rq_task;
997 
998 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
999 		copied = repsize;
1000 
1001 	/* Suck it into the iovec, verify checksum if not done by hw. */
1002 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1003 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
1004 		goto out_unlock;
1005 	}
1006 
1007 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
1008 
1009 	xprt_adjust_cwnd(xprt, task, copied);
1010 	xprt_complete_rqst(task, copied);
1011 
1012  out_unlock:
1013 	spin_unlock(&xprt->transport_lock);
1014  dropit:
1015 	skb_free_datagram(sk, skb);
1016  out:
1017 	read_unlock_bh(&sk->sk_callback_lock);
1018 }
1019 
1020 /*
1021  * Helper function to force a TCP close if the server is sending
1022  * junk and/or it has put us in CLOSE_WAIT
1023  */
1024 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1025 {
1026 	set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1027 	xprt_force_disconnect(xprt);
1028 }
1029 
1030 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1031 {
1032 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1033 	size_t len, used;
1034 	char *p;
1035 
1036 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1037 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1038 	used = xdr_skb_read_bits(desc, p, len);
1039 	transport->tcp_offset += used;
1040 	if (used != len)
1041 		return;
1042 
1043 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1044 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1045 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1046 	else
1047 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1048 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1049 
1050 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1051 	transport->tcp_offset = 0;
1052 
1053 	/* Sanity check of the record length */
1054 	if (unlikely(transport->tcp_reclen < 8)) {
1055 		dprintk("RPC:       invalid TCP record fragment length\n");
1056 		xs_tcp_force_close(xprt);
1057 		return;
1058 	}
1059 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1060 			transport->tcp_reclen);
1061 }
1062 
1063 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1064 {
1065 	if (transport->tcp_offset == transport->tcp_reclen) {
1066 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1067 		transport->tcp_offset = 0;
1068 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1069 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1070 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1071 			transport->tcp_copied = 0;
1072 		}
1073 	}
1074 }
1075 
1076 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1077 {
1078 	size_t len, used;
1079 	char *p;
1080 
1081 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1082 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
1083 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1084 	used = xdr_skb_read_bits(desc, p, len);
1085 	transport->tcp_offset += used;
1086 	if (used != len)
1087 		return;
1088 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1089 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1090 	transport->tcp_copied = 4;
1091 	dprintk("RPC:       reading %s XID %08x\n",
1092 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1093 							      : "request with",
1094 			ntohl(transport->tcp_xid));
1095 	xs_tcp_check_fraghdr(transport);
1096 }
1097 
1098 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1099 				       struct xdr_skb_reader *desc)
1100 {
1101 	size_t len, used;
1102 	u32 offset;
1103 	char *p;
1104 
1105 	/*
1106 	 * We want transport->tcp_offset to be 8 at the end of this routine
1107 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1108 	 * When this function is called for the first time,
1109 	 * transport->tcp_offset is 4 (after having already read the xid).
1110 	 */
1111 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1112 	len = sizeof(transport->tcp_calldir) - offset;
1113 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
1114 	p = ((char *) &transport->tcp_calldir) + offset;
1115 	used = xdr_skb_read_bits(desc, p, len);
1116 	transport->tcp_offset += used;
1117 	if (used != len)
1118 		return;
1119 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1120 	/*
1121 	 * We don't yet have the XDR buffer, so we will write the calldir
1122 	 * out after we get the buffer from the 'struct rpc_rqst'
1123 	 */
1124 	switch (ntohl(transport->tcp_calldir)) {
1125 	case RPC_REPLY:
1126 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1127 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1128 		transport->tcp_flags |= TCP_RPC_REPLY;
1129 		break;
1130 	case RPC_CALL:
1131 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1132 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1133 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1134 		break;
1135 	default:
1136 		dprintk("RPC:       invalid request message type\n");
1137 		xs_tcp_force_close(&transport->xprt);
1138 	}
1139 	xs_tcp_check_fraghdr(transport);
1140 }
1141 
1142 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1143 				     struct xdr_skb_reader *desc,
1144 				     struct rpc_rqst *req)
1145 {
1146 	struct sock_xprt *transport =
1147 				container_of(xprt, struct sock_xprt, xprt);
1148 	struct xdr_buf *rcvbuf;
1149 	size_t len;
1150 	ssize_t r;
1151 
1152 	rcvbuf = &req->rq_private_buf;
1153 
1154 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1155 		/*
1156 		 * Save the RPC direction in the XDR buffer
1157 		 */
1158 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1159 			&transport->tcp_calldir,
1160 			sizeof(transport->tcp_calldir));
1161 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1162 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1163 	}
1164 
1165 	len = desc->count;
1166 	if (len > transport->tcp_reclen - transport->tcp_offset) {
1167 		struct xdr_skb_reader my_desc;
1168 
1169 		len = transport->tcp_reclen - transport->tcp_offset;
1170 		memcpy(&my_desc, desc, sizeof(my_desc));
1171 		my_desc.count = len;
1172 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1173 					  &my_desc, xdr_skb_read_bits);
1174 		desc->count -= r;
1175 		desc->offset += r;
1176 	} else
1177 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1178 					  desc, xdr_skb_read_bits);
1179 
1180 	if (r > 0) {
1181 		transport->tcp_copied += r;
1182 		transport->tcp_offset += r;
1183 	}
1184 	if (r != len) {
1185 		/* Error when copying to the receive buffer,
1186 		 * usually because we weren't able to allocate
1187 		 * additional buffer pages. All we can do now
1188 		 * is turn off TCP_RCV_COPY_DATA, so the request
1189 		 * will not receive any additional updates,
1190 		 * and time out.
1191 		 * Any remaining data from this record will
1192 		 * be discarded.
1193 		 */
1194 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1195 		dprintk("RPC:       XID %08x truncated request\n",
1196 				ntohl(transport->tcp_xid));
1197 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1198 				"tcp_offset = %u, tcp_reclen = %u\n",
1199 				xprt, transport->tcp_copied,
1200 				transport->tcp_offset, transport->tcp_reclen);
1201 		return;
1202 	}
1203 
1204 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1205 			ntohl(transport->tcp_xid), r);
1206 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1207 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1208 			transport->tcp_offset, transport->tcp_reclen);
1209 
1210 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1211 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1212 	else if (transport->tcp_offset == transport->tcp_reclen) {
1213 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1214 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1215 	}
1216 }
1217 
1218 /*
1219  * Finds the request corresponding to the RPC xid and invokes the common
1220  * tcp read code to read the data.
1221  */
1222 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1223 				    struct xdr_skb_reader *desc)
1224 {
1225 	struct sock_xprt *transport =
1226 				container_of(xprt, struct sock_xprt, xprt);
1227 	struct rpc_rqst *req;
1228 
1229 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1230 
1231 	/* Find and lock the request corresponding to this xid */
1232 	spin_lock(&xprt->transport_lock);
1233 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1234 	if (!req) {
1235 		dprintk("RPC:       XID %08x request not found!\n",
1236 				ntohl(transport->tcp_xid));
1237 		spin_unlock(&xprt->transport_lock);
1238 		return -1;
1239 	}
1240 
1241 	xs_tcp_read_common(xprt, desc, req);
1242 
1243 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1244 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1245 
1246 	spin_unlock(&xprt->transport_lock);
1247 	return 0;
1248 }
1249 
1250 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1251 /*
1252  * Obtains an rpc_rqst previously allocated and invokes the common
1253  * tcp read code to read the data.  The result is placed in the callback
1254  * queue.
1255  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1256  * connection and return -1.
1257  */
1258 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1259 				       struct xdr_skb_reader *desc)
1260 {
1261 	struct sock_xprt *transport =
1262 				container_of(xprt, struct sock_xprt, xprt);
1263 	struct rpc_rqst *req;
1264 
1265 	req = xprt_alloc_bc_request(xprt);
1266 	if (req == NULL) {
1267 		printk(KERN_WARNING "Callback slot table overflowed\n");
1268 		xprt_force_disconnect(xprt);
1269 		return -1;
1270 	}
1271 
1272 	req->rq_xid = transport->tcp_xid;
1273 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1274 	xs_tcp_read_common(xprt, desc, req);
1275 
1276 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1277 		struct svc_serv *bc_serv = xprt->bc_serv;
1278 
1279 		/*
1280 		 * Add callback request to callback list.  The callback
1281 		 * service sleeps on the sv_cb_waitq waiting for new
1282 		 * requests.  Wake it up after adding enqueing the
1283 		 * request.
1284 		 */
1285 		dprintk("RPC:       add callback request to list\n");
1286 		spin_lock(&bc_serv->sv_cb_lock);
1287 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1288 		spin_unlock(&bc_serv->sv_cb_lock);
1289 		wake_up(&bc_serv->sv_cb_waitq);
1290 	}
1291 
1292 	req->rq_private_buf.len = transport->tcp_copied;
1293 
1294 	return 0;
1295 }
1296 
1297 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1298 					struct xdr_skb_reader *desc)
1299 {
1300 	struct sock_xprt *transport =
1301 				container_of(xprt, struct sock_xprt, xprt);
1302 
1303 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1304 		xs_tcp_read_reply(xprt, desc) :
1305 		xs_tcp_read_callback(xprt, desc);
1306 }
1307 #else
1308 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1309 					struct xdr_skb_reader *desc)
1310 {
1311 	return xs_tcp_read_reply(xprt, desc);
1312 }
1313 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1314 
1315 /*
1316  * Read data off the transport.  This can be either an RPC_CALL or an
1317  * RPC_REPLY.  Relay the processing to helper functions.
1318  */
1319 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1320 				    struct xdr_skb_reader *desc)
1321 {
1322 	struct sock_xprt *transport =
1323 				container_of(xprt, struct sock_xprt, xprt);
1324 
1325 	if (_xs_tcp_read_data(xprt, desc) == 0)
1326 		xs_tcp_check_fraghdr(transport);
1327 	else {
1328 		/*
1329 		 * The transport_lock protects the request handling.
1330 		 * There's no need to hold it to update the tcp_flags.
1331 		 */
1332 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1333 	}
1334 }
1335 
1336 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1337 {
1338 	size_t len;
1339 
1340 	len = transport->tcp_reclen - transport->tcp_offset;
1341 	if (len > desc->count)
1342 		len = desc->count;
1343 	desc->count -= len;
1344 	desc->offset += len;
1345 	transport->tcp_offset += len;
1346 	dprintk("RPC:       discarded %Zu bytes\n", len);
1347 	xs_tcp_check_fraghdr(transport);
1348 }
1349 
1350 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1351 {
1352 	struct rpc_xprt *xprt = rd_desc->arg.data;
1353 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1354 	struct xdr_skb_reader desc = {
1355 		.skb	= skb,
1356 		.offset	= offset,
1357 		.count	= len,
1358 	};
1359 
1360 	dprintk("RPC:       xs_tcp_data_recv started\n");
1361 	do {
1362 		/* Read in a new fragment marker if necessary */
1363 		/* Can we ever really expect to get completely empty fragments? */
1364 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1365 			xs_tcp_read_fraghdr(xprt, &desc);
1366 			continue;
1367 		}
1368 		/* Read in the xid if necessary */
1369 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1370 			xs_tcp_read_xid(transport, &desc);
1371 			continue;
1372 		}
1373 		/* Read in the call/reply flag */
1374 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1375 			xs_tcp_read_calldir(transport, &desc);
1376 			continue;
1377 		}
1378 		/* Read in the request data */
1379 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1380 			xs_tcp_read_data(xprt, &desc);
1381 			continue;
1382 		}
1383 		/* Skip over any trailing bytes on short reads */
1384 		xs_tcp_read_discard(transport, &desc);
1385 	} while (desc.count);
1386 	dprintk("RPC:       xs_tcp_data_recv done\n");
1387 	return len - desc.count;
1388 }
1389 
1390 /**
1391  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1392  * @sk: socket with data to read
1393  * @bytes: how much data to read
1394  *
1395  */
1396 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1397 {
1398 	struct rpc_xprt *xprt;
1399 	read_descriptor_t rd_desc;
1400 	int read;
1401 
1402 	dprintk("RPC:       xs_tcp_data_ready...\n");
1403 
1404 	read_lock_bh(&sk->sk_callback_lock);
1405 	if (!(xprt = xprt_from_sock(sk)))
1406 		goto out;
1407 	/* Any data means we had a useful conversation, so
1408 	 * the we don't need to delay the next reconnect
1409 	 */
1410 	if (xprt->reestablish_timeout)
1411 		xprt->reestablish_timeout = 0;
1412 
1413 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1414 	rd_desc.arg.data = xprt;
1415 	do {
1416 		rd_desc.count = 65536;
1417 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1418 	} while (read > 0);
1419 out:
1420 	read_unlock_bh(&sk->sk_callback_lock);
1421 }
1422 
1423 /*
1424  * Do the equivalent of linger/linger2 handling for dealing with
1425  * broken servers that don't close the socket in a timely
1426  * fashion
1427  */
1428 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1429 		unsigned long timeout)
1430 {
1431 	struct sock_xprt *transport;
1432 
1433 	if (xprt_test_and_set_connecting(xprt))
1434 		return;
1435 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1436 	transport = container_of(xprt, struct sock_xprt, xprt);
1437 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1438 			   timeout);
1439 }
1440 
1441 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1442 {
1443 	struct sock_xprt *transport;
1444 
1445 	transport = container_of(xprt, struct sock_xprt, xprt);
1446 
1447 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1448 	    !cancel_delayed_work(&transport->connect_worker))
1449 		return;
1450 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1451 	xprt_clear_connecting(xprt);
1452 }
1453 
1454 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1455 {
1456 	smp_mb__before_clear_bit();
1457 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1458 	clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1459 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1460 	clear_bit(XPRT_CLOSING, &xprt->state);
1461 	smp_mb__after_clear_bit();
1462 }
1463 
1464 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1465 {
1466 	xs_sock_reset_connection_flags(xprt);
1467 	/* Mark transport as closed and wake up all pending tasks */
1468 	xprt_disconnect_done(xprt);
1469 }
1470 
1471 /**
1472  * xs_tcp_state_change - callback to handle TCP socket state changes
1473  * @sk: socket whose state has changed
1474  *
1475  */
1476 static void xs_tcp_state_change(struct sock *sk)
1477 {
1478 	struct rpc_xprt *xprt;
1479 
1480 	read_lock_bh(&sk->sk_callback_lock);
1481 	if (!(xprt = xprt_from_sock(sk)))
1482 		goto out;
1483 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1484 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1485 			sk->sk_state, xprt_connected(xprt),
1486 			sock_flag(sk, SOCK_DEAD),
1487 			sock_flag(sk, SOCK_ZAPPED),
1488 			sk->sk_shutdown);
1489 
1490 	switch (sk->sk_state) {
1491 	case TCP_ESTABLISHED:
1492 		spin_lock(&xprt->transport_lock);
1493 		if (!xprt_test_and_set_connected(xprt)) {
1494 			struct sock_xprt *transport = container_of(xprt,
1495 					struct sock_xprt, xprt);
1496 
1497 			/* Reset TCP record info */
1498 			transport->tcp_offset = 0;
1499 			transport->tcp_reclen = 0;
1500 			transport->tcp_copied = 0;
1501 			transport->tcp_flags =
1502 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1503 
1504 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1505 		}
1506 		spin_unlock(&xprt->transport_lock);
1507 		break;
1508 	case TCP_FIN_WAIT1:
1509 		/* The client initiated a shutdown of the socket */
1510 		xprt->connect_cookie++;
1511 		xprt->reestablish_timeout = 0;
1512 		set_bit(XPRT_CLOSING, &xprt->state);
1513 		smp_mb__before_clear_bit();
1514 		clear_bit(XPRT_CONNECTED, &xprt->state);
1515 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1516 		smp_mb__after_clear_bit();
1517 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1518 		break;
1519 	case TCP_CLOSE_WAIT:
1520 		/* The server initiated a shutdown of the socket */
1521 		xprt->connect_cookie++;
1522 		clear_bit(XPRT_CONNECTED, &xprt->state);
1523 		xs_tcp_force_close(xprt);
1524 	case TCP_CLOSING:
1525 		/*
1526 		 * If the server closed down the connection, make sure that
1527 		 * we back off before reconnecting
1528 		 */
1529 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1530 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1531 		break;
1532 	case TCP_LAST_ACK:
1533 		set_bit(XPRT_CLOSING, &xprt->state);
1534 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1535 		smp_mb__before_clear_bit();
1536 		clear_bit(XPRT_CONNECTED, &xprt->state);
1537 		smp_mb__after_clear_bit();
1538 		break;
1539 	case TCP_CLOSE:
1540 		xs_tcp_cancel_linger_timeout(xprt);
1541 		xs_sock_mark_closed(xprt);
1542 	}
1543  out:
1544 	read_unlock_bh(&sk->sk_callback_lock);
1545 }
1546 
1547 static void xs_write_space(struct sock *sk)
1548 {
1549 	struct socket *sock;
1550 	struct rpc_xprt *xprt;
1551 
1552 	if (unlikely(!(sock = sk->sk_socket)))
1553 		return;
1554 	clear_bit(SOCK_NOSPACE, &sock->flags);
1555 
1556 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1557 		return;
1558 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1559 		return;
1560 
1561 	xprt_write_space(xprt);
1562 }
1563 
1564 /**
1565  * xs_udp_write_space - callback invoked when socket buffer space
1566  *                             becomes available
1567  * @sk: socket whose state has changed
1568  *
1569  * Called when more output buffer space is available for this socket.
1570  * We try not to wake our writers until they can make "significant"
1571  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1572  * with a bunch of small requests.
1573  */
1574 static void xs_udp_write_space(struct sock *sk)
1575 {
1576 	read_lock_bh(&sk->sk_callback_lock);
1577 
1578 	/* from net/core/sock.c:sock_def_write_space */
1579 	if (sock_writeable(sk))
1580 		xs_write_space(sk);
1581 
1582 	read_unlock_bh(&sk->sk_callback_lock);
1583 }
1584 
1585 /**
1586  * xs_tcp_write_space - callback invoked when socket buffer space
1587  *                             becomes available
1588  * @sk: socket whose state has changed
1589  *
1590  * Called when more output buffer space is available for this socket.
1591  * We try not to wake our writers until they can make "significant"
1592  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1593  * with a bunch of small requests.
1594  */
1595 static void xs_tcp_write_space(struct sock *sk)
1596 {
1597 	read_lock_bh(&sk->sk_callback_lock);
1598 
1599 	/* from net/core/stream.c:sk_stream_write_space */
1600 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1601 		xs_write_space(sk);
1602 
1603 	read_unlock_bh(&sk->sk_callback_lock);
1604 }
1605 
1606 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1607 {
1608 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1609 	struct sock *sk = transport->inet;
1610 
1611 	if (transport->rcvsize) {
1612 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1613 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1614 	}
1615 	if (transport->sndsize) {
1616 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1617 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1618 		sk->sk_write_space(sk);
1619 	}
1620 }
1621 
1622 /**
1623  * xs_udp_set_buffer_size - set send and receive limits
1624  * @xprt: generic transport
1625  * @sndsize: requested size of send buffer, in bytes
1626  * @rcvsize: requested size of receive buffer, in bytes
1627  *
1628  * Set socket send and receive buffer size limits.
1629  */
1630 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1631 {
1632 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1633 
1634 	transport->sndsize = 0;
1635 	if (sndsize)
1636 		transport->sndsize = sndsize + 1024;
1637 	transport->rcvsize = 0;
1638 	if (rcvsize)
1639 		transport->rcvsize = rcvsize + 1024;
1640 
1641 	xs_udp_do_set_buffer_size(xprt);
1642 }
1643 
1644 /**
1645  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1646  * @task: task that timed out
1647  *
1648  * Adjust the congestion window after a retransmit timeout has occurred.
1649  */
1650 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1651 {
1652 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1653 }
1654 
1655 static unsigned short xs_get_random_port(void)
1656 {
1657 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1658 	unsigned short rand = (unsigned short) net_random() % range;
1659 	return rand + xprt_min_resvport;
1660 }
1661 
1662 /**
1663  * xs_set_port - reset the port number in the remote endpoint address
1664  * @xprt: generic transport
1665  * @port: new port number
1666  *
1667  */
1668 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1669 {
1670 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1671 
1672 	rpc_set_port(xs_addr(xprt), port);
1673 	xs_update_peer_port(xprt);
1674 }
1675 
1676 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1677 {
1678 	unsigned short port = transport->srcport;
1679 
1680 	if (port == 0 && transport->xprt.resvport)
1681 		port = xs_get_random_port();
1682 	return port;
1683 }
1684 
1685 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1686 {
1687 	if (transport->srcport != 0)
1688 		transport->srcport = 0;
1689 	if (!transport->xprt.resvport)
1690 		return 0;
1691 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1692 		return xprt_max_resvport;
1693 	return --port;
1694 }
1695 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1696 {
1697 	struct sockaddr_storage myaddr;
1698 	int err, nloop = 0;
1699 	unsigned short port = xs_get_srcport(transport);
1700 	unsigned short last;
1701 
1702 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1703 	do {
1704 		rpc_set_port((struct sockaddr *)&myaddr, port);
1705 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1706 				transport->xprt.addrlen);
1707 		if (port == 0)
1708 			break;
1709 		if (err == 0) {
1710 			transport->srcport = port;
1711 			break;
1712 		}
1713 		last = port;
1714 		port = xs_next_srcport(transport, port);
1715 		if (port > last)
1716 			nloop++;
1717 	} while (err == -EADDRINUSE && nloop != 2);
1718 
1719 	if (myaddr.ss_family == AF_INET)
1720 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1721 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1722 				port, err ? "failed" : "ok", err);
1723 	else
1724 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1725 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1726 				port, err ? "failed" : "ok", err);
1727 	return err;
1728 }
1729 
1730 /*
1731  * We don't support autobind on AF_LOCAL sockets
1732  */
1733 static void xs_local_rpcbind(struct rpc_task *task)
1734 {
1735 	rcu_read_lock();
1736 	xprt_set_bound(rcu_dereference(task->tk_client->cl_xprt));
1737 	rcu_read_unlock();
1738 }
1739 
1740 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1741 {
1742 }
1743 
1744 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1745 static struct lock_class_key xs_key[2];
1746 static struct lock_class_key xs_slock_key[2];
1747 
1748 static inline void xs_reclassify_socketu(struct socket *sock)
1749 {
1750 	struct sock *sk = sock->sk;
1751 
1752 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1753 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1754 }
1755 
1756 static inline void xs_reclassify_socket4(struct socket *sock)
1757 {
1758 	struct sock *sk = sock->sk;
1759 
1760 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1761 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1762 }
1763 
1764 static inline void xs_reclassify_socket6(struct socket *sock)
1765 {
1766 	struct sock *sk = sock->sk;
1767 
1768 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1769 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1770 }
1771 
1772 static inline void xs_reclassify_socket(int family, struct socket *sock)
1773 {
1774 	WARN_ON_ONCE(sock_owned_by_user(sock->sk));
1775 	if (sock_owned_by_user(sock->sk))
1776 		return;
1777 
1778 	switch (family) {
1779 	case AF_LOCAL:
1780 		xs_reclassify_socketu(sock);
1781 		break;
1782 	case AF_INET:
1783 		xs_reclassify_socket4(sock);
1784 		break;
1785 	case AF_INET6:
1786 		xs_reclassify_socket6(sock);
1787 		break;
1788 	}
1789 }
1790 #else
1791 static inline void xs_reclassify_socketu(struct socket *sock)
1792 {
1793 }
1794 
1795 static inline void xs_reclassify_socket4(struct socket *sock)
1796 {
1797 }
1798 
1799 static inline void xs_reclassify_socket6(struct socket *sock)
1800 {
1801 }
1802 
1803 static inline void xs_reclassify_socket(int family, struct socket *sock)
1804 {
1805 }
1806 #endif
1807 
1808 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1809 		struct sock_xprt *transport, int family, int type, int protocol)
1810 {
1811 	struct socket *sock;
1812 	int err;
1813 
1814 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1815 	if (err < 0) {
1816 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1817 				protocol, -err);
1818 		goto out;
1819 	}
1820 	xs_reclassify_socket(family, sock);
1821 
1822 	err = xs_bind(transport, sock);
1823 	if (err) {
1824 		sock_release(sock);
1825 		goto out;
1826 	}
1827 
1828 	return sock;
1829 out:
1830 	return ERR_PTR(err);
1831 }
1832 
1833 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1834 				      struct socket *sock)
1835 {
1836 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1837 									xprt);
1838 
1839 	if (!transport->inet) {
1840 		struct sock *sk = sock->sk;
1841 
1842 		write_lock_bh(&sk->sk_callback_lock);
1843 
1844 		xs_save_old_callbacks(transport, sk);
1845 
1846 		sk->sk_user_data = xprt;
1847 		sk->sk_data_ready = xs_local_data_ready;
1848 		sk->sk_write_space = xs_udp_write_space;
1849 		sk->sk_allocation = GFP_ATOMIC;
1850 
1851 		xprt_clear_connected(xprt);
1852 
1853 		/* Reset to new socket */
1854 		transport->sock = sock;
1855 		transport->inet = sk;
1856 
1857 		write_unlock_bh(&sk->sk_callback_lock);
1858 	}
1859 
1860 	/* Tell the socket layer to start connecting... */
1861 	xprt->stat.connect_count++;
1862 	xprt->stat.connect_start = jiffies;
1863 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1864 }
1865 
1866 /**
1867  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1868  * @xprt: RPC transport to connect
1869  * @transport: socket transport to connect
1870  * @create_sock: function to create a socket of the correct type
1871  */
1872 static int xs_local_setup_socket(struct sock_xprt *transport)
1873 {
1874 	struct rpc_xprt *xprt = &transport->xprt;
1875 	struct socket *sock;
1876 	int status = -EIO;
1877 
1878 	current->flags |= PF_FSTRANS;
1879 
1880 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1881 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1882 					SOCK_STREAM, 0, &sock, 1);
1883 	if (status < 0) {
1884 		dprintk("RPC:       can't create AF_LOCAL "
1885 			"transport socket (%d).\n", -status);
1886 		goto out;
1887 	}
1888 	xs_reclassify_socketu(sock);
1889 
1890 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1891 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1892 
1893 	status = xs_local_finish_connecting(xprt, sock);
1894 	switch (status) {
1895 	case 0:
1896 		dprintk("RPC:       xprt %p connected to %s\n",
1897 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1898 		xprt_set_connected(xprt);
1899 		break;
1900 	case -ENOENT:
1901 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1902 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1903 		break;
1904 	case -ECONNREFUSED:
1905 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1906 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1907 		break;
1908 	default:
1909 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1910 				__func__, -status,
1911 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1912 	}
1913 
1914 out:
1915 	xprt_clear_connecting(xprt);
1916 	xprt_wake_pending_tasks(xprt, status);
1917 	current->flags &= ~PF_FSTRANS;
1918 	return status;
1919 }
1920 
1921 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
1922 {
1923 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1924 	int ret;
1925 
1926 	 if (RPC_IS_ASYNC(task)) {
1927 		/*
1928 		 * We want the AF_LOCAL connect to be resolved in the
1929 		 * filesystem namespace of the process making the rpc
1930 		 * call.  Thus we connect synchronously.
1931 		 *
1932 		 * If we want to support asynchronous AF_LOCAL calls,
1933 		 * we'll need to figure out how to pass a namespace to
1934 		 * connect.
1935 		 */
1936 		rpc_exit(task, -ENOTCONN);
1937 		return;
1938 	}
1939 	ret = xs_local_setup_socket(transport);
1940 	if (ret && !RPC_IS_SOFTCONN(task))
1941 		msleep_interruptible(15000);
1942 }
1943 
1944 #ifdef CONFIG_SUNRPC_SWAP
1945 static void xs_set_memalloc(struct rpc_xprt *xprt)
1946 {
1947 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1948 			xprt);
1949 
1950 	if (xprt->swapper)
1951 		sk_set_memalloc(transport->inet);
1952 }
1953 
1954 /**
1955  * xs_swapper - Tag this transport as being used for swap.
1956  * @xprt: transport to tag
1957  * @enable: enable/disable
1958  *
1959  */
1960 int xs_swapper(struct rpc_xprt *xprt, int enable)
1961 {
1962 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1963 			xprt);
1964 	int err = 0;
1965 
1966 	if (enable) {
1967 		xprt->swapper++;
1968 		xs_set_memalloc(xprt);
1969 	} else if (xprt->swapper) {
1970 		xprt->swapper--;
1971 		sk_clear_memalloc(transport->inet);
1972 	}
1973 
1974 	return err;
1975 }
1976 EXPORT_SYMBOL_GPL(xs_swapper);
1977 #else
1978 static void xs_set_memalloc(struct rpc_xprt *xprt)
1979 {
1980 }
1981 #endif
1982 
1983 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1984 {
1985 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1986 
1987 	if (!transport->inet) {
1988 		struct sock *sk = sock->sk;
1989 
1990 		write_lock_bh(&sk->sk_callback_lock);
1991 
1992 		xs_save_old_callbacks(transport, sk);
1993 
1994 		sk->sk_user_data = xprt;
1995 		sk->sk_data_ready = xs_udp_data_ready;
1996 		sk->sk_write_space = xs_udp_write_space;
1997 		sk->sk_no_check = UDP_CSUM_NORCV;
1998 		sk->sk_allocation = GFP_ATOMIC;
1999 
2000 		xprt_set_connected(xprt);
2001 
2002 		/* Reset to new socket */
2003 		transport->sock = sock;
2004 		transport->inet = sk;
2005 
2006 		xs_set_memalloc(xprt);
2007 
2008 		write_unlock_bh(&sk->sk_callback_lock);
2009 	}
2010 	xs_udp_do_set_buffer_size(xprt);
2011 }
2012 
2013 static void xs_udp_setup_socket(struct work_struct *work)
2014 {
2015 	struct sock_xprt *transport =
2016 		container_of(work, struct sock_xprt, connect_worker.work);
2017 	struct rpc_xprt *xprt = &transport->xprt;
2018 	struct socket *sock = transport->sock;
2019 	int status = -EIO;
2020 
2021 	current->flags |= PF_FSTRANS;
2022 
2023 	/* Start by resetting any existing state */
2024 	xs_reset_transport(transport);
2025 	sock = xs_create_sock(xprt, transport,
2026 			xs_addr(xprt)->sa_family, SOCK_DGRAM, IPPROTO_UDP);
2027 	if (IS_ERR(sock))
2028 		goto out;
2029 
2030 	dprintk("RPC:       worker connecting xprt %p via %s to "
2031 				"%s (port %s)\n", xprt,
2032 			xprt->address_strings[RPC_DISPLAY_PROTO],
2033 			xprt->address_strings[RPC_DISPLAY_ADDR],
2034 			xprt->address_strings[RPC_DISPLAY_PORT]);
2035 
2036 	xs_udp_finish_connecting(xprt, sock);
2037 	status = 0;
2038 out:
2039 	xprt_clear_connecting(xprt);
2040 	xprt_wake_pending_tasks(xprt, status);
2041 	current->flags &= ~PF_FSTRANS;
2042 }
2043 
2044 /*
2045  * We need to preserve the port number so the reply cache on the server can
2046  * find our cached RPC replies when we get around to reconnecting.
2047  */
2048 static void xs_abort_connection(struct sock_xprt *transport)
2049 {
2050 	int result;
2051 	struct sockaddr any;
2052 
2053 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", transport);
2054 
2055 	/*
2056 	 * Disconnect the transport socket by doing a connect operation
2057 	 * with AF_UNSPEC.  This should return immediately...
2058 	 */
2059 	memset(&any, 0, sizeof(any));
2060 	any.sa_family = AF_UNSPEC;
2061 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
2062 	if (!result)
2063 		xs_sock_reset_connection_flags(&transport->xprt);
2064 	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
2065 }
2066 
2067 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
2068 {
2069 	unsigned int state = transport->inet->sk_state;
2070 
2071 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
2072 		/* we don't need to abort the connection if the socket
2073 		 * hasn't undergone a shutdown
2074 		 */
2075 		if (transport->inet->sk_shutdown == 0)
2076 			return;
2077 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
2078 				__func__, transport->inet->sk_shutdown);
2079 	}
2080 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
2081 		/* we don't need to abort the connection if the socket
2082 		 * hasn't undergone a shutdown
2083 		 */
2084 		if (transport->inet->sk_shutdown == 0)
2085 			return;
2086 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
2087 				"sk_shutdown set to %d\n",
2088 				__func__, transport->inet->sk_shutdown);
2089 	}
2090 	xs_abort_connection(transport);
2091 }
2092 
2093 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2094 {
2095 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2096 	int ret = -ENOTCONN;
2097 
2098 	if (!transport->inet) {
2099 		struct sock *sk = sock->sk;
2100 
2101 		write_lock_bh(&sk->sk_callback_lock);
2102 
2103 		xs_save_old_callbacks(transport, sk);
2104 
2105 		sk->sk_user_data = xprt;
2106 		sk->sk_data_ready = xs_tcp_data_ready;
2107 		sk->sk_state_change = xs_tcp_state_change;
2108 		sk->sk_write_space = xs_tcp_write_space;
2109 		sk->sk_allocation = GFP_ATOMIC;
2110 
2111 		/* socket options */
2112 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
2113 		sock_reset_flag(sk, SOCK_LINGER);
2114 		tcp_sk(sk)->linger2 = 0;
2115 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2116 
2117 		xprt_clear_connected(xprt);
2118 
2119 		/* Reset to new socket */
2120 		transport->sock = sock;
2121 		transport->inet = sk;
2122 
2123 		write_unlock_bh(&sk->sk_callback_lock);
2124 	}
2125 
2126 	if (!xprt_bound(xprt))
2127 		goto out;
2128 
2129 	xs_set_memalloc(xprt);
2130 
2131 	/* Tell the socket layer to start connecting... */
2132 	xprt->stat.connect_count++;
2133 	xprt->stat.connect_start = jiffies;
2134 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2135 	switch (ret) {
2136 	case 0:
2137 	case -EINPROGRESS:
2138 		/* SYN_SENT! */
2139 		xprt->connect_cookie++;
2140 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2141 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2142 	}
2143 out:
2144 	return ret;
2145 }
2146 
2147 /**
2148  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2149  * @xprt: RPC transport to connect
2150  * @transport: socket transport to connect
2151  * @create_sock: function to create a socket of the correct type
2152  *
2153  * Invoked by a work queue tasklet.
2154  */
2155 static void xs_tcp_setup_socket(struct work_struct *work)
2156 {
2157 	struct sock_xprt *transport =
2158 		container_of(work, struct sock_xprt, connect_worker.work);
2159 	struct socket *sock = transport->sock;
2160 	struct rpc_xprt *xprt = &transport->xprt;
2161 	int status = -EIO;
2162 
2163 	current->flags |= PF_FSTRANS;
2164 
2165 	if (!sock) {
2166 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
2167 		sock = xs_create_sock(xprt, transport,
2168 				xs_addr(xprt)->sa_family, SOCK_STREAM, IPPROTO_TCP);
2169 		if (IS_ERR(sock)) {
2170 			status = PTR_ERR(sock);
2171 			goto out;
2172 		}
2173 	} else {
2174 		int abort_and_exit;
2175 
2176 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
2177 				&xprt->state);
2178 		/* "close" the socket, preserving the local port */
2179 		xs_tcp_reuse_connection(transport);
2180 
2181 		if (abort_and_exit)
2182 			goto out_eagain;
2183 	}
2184 
2185 	dprintk("RPC:       worker connecting xprt %p via %s to "
2186 				"%s (port %s)\n", xprt,
2187 			xprt->address_strings[RPC_DISPLAY_PROTO],
2188 			xprt->address_strings[RPC_DISPLAY_ADDR],
2189 			xprt->address_strings[RPC_DISPLAY_PORT]);
2190 
2191 	status = xs_tcp_finish_connecting(xprt, sock);
2192 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2193 			xprt, -status, xprt_connected(xprt),
2194 			sock->sk->sk_state);
2195 	switch (status) {
2196 	default:
2197 		printk("%s: connect returned unhandled error %d\n",
2198 			__func__, status);
2199 	case -EADDRNOTAVAIL:
2200 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2201 		 * and retry
2202 		 */
2203 		xs_tcp_force_close(xprt);
2204 		break;
2205 	case -ECONNREFUSED:
2206 	case -ECONNRESET:
2207 	case -ENETUNREACH:
2208 		/* retry with existing socket, after a delay */
2209 	case 0:
2210 	case -EINPROGRESS:
2211 	case -EALREADY:
2212 		xprt_clear_connecting(xprt);
2213 		current->flags &= ~PF_FSTRANS;
2214 		return;
2215 	case -EINVAL:
2216 		/* Happens, for instance, if the user specified a link
2217 		 * local IPv6 address without a scope-id.
2218 		 */
2219 		goto out;
2220 	}
2221 out_eagain:
2222 	status = -EAGAIN;
2223 out:
2224 	xprt_clear_connecting(xprt);
2225 	xprt_wake_pending_tasks(xprt, status);
2226 	current->flags &= ~PF_FSTRANS;
2227 }
2228 
2229 /**
2230  * xs_connect - connect a socket to a remote endpoint
2231  * @xprt: pointer to transport structure
2232  * @task: address of RPC task that manages state of connect request
2233  *
2234  * TCP: If the remote end dropped the connection, delay reconnecting.
2235  *
2236  * UDP socket connects are synchronous, but we use a work queue anyway
2237  * to guarantee that even unprivileged user processes can set up a
2238  * socket on a privileged port.
2239  *
2240  * If a UDP socket connect fails, the delay behavior here prevents
2241  * retry floods (hard mounts).
2242  */
2243 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2244 {
2245 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2246 
2247 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2248 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2249 				"seconds\n",
2250 				xprt, xprt->reestablish_timeout / HZ);
2251 		queue_delayed_work(rpciod_workqueue,
2252 				   &transport->connect_worker,
2253 				   xprt->reestablish_timeout);
2254 		xprt->reestablish_timeout <<= 1;
2255 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2256 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2257 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2258 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2259 	} else {
2260 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2261 		queue_delayed_work(rpciod_workqueue,
2262 				   &transport->connect_worker, 0);
2263 	}
2264 }
2265 
2266 /**
2267  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2268  * @xprt: rpc_xprt struct containing statistics
2269  * @seq: output file
2270  *
2271  */
2272 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2273 {
2274 	long idle_time = 0;
2275 
2276 	if (xprt_connected(xprt))
2277 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2278 
2279 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2280 			"%llu %llu %lu %llu %llu\n",
2281 			xprt->stat.bind_count,
2282 			xprt->stat.connect_count,
2283 			xprt->stat.connect_time,
2284 			idle_time,
2285 			xprt->stat.sends,
2286 			xprt->stat.recvs,
2287 			xprt->stat.bad_xids,
2288 			xprt->stat.req_u,
2289 			xprt->stat.bklog_u,
2290 			xprt->stat.max_slots,
2291 			xprt->stat.sending_u,
2292 			xprt->stat.pending_u);
2293 }
2294 
2295 /**
2296  * xs_udp_print_stats - display UDP socket-specifc stats
2297  * @xprt: rpc_xprt struct containing statistics
2298  * @seq: output file
2299  *
2300  */
2301 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2302 {
2303 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2304 
2305 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2306 			"%lu %llu %llu\n",
2307 			transport->srcport,
2308 			xprt->stat.bind_count,
2309 			xprt->stat.sends,
2310 			xprt->stat.recvs,
2311 			xprt->stat.bad_xids,
2312 			xprt->stat.req_u,
2313 			xprt->stat.bklog_u,
2314 			xprt->stat.max_slots,
2315 			xprt->stat.sending_u,
2316 			xprt->stat.pending_u);
2317 }
2318 
2319 /**
2320  * xs_tcp_print_stats - display TCP socket-specifc stats
2321  * @xprt: rpc_xprt struct containing statistics
2322  * @seq: output file
2323  *
2324  */
2325 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2326 {
2327 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2328 	long idle_time = 0;
2329 
2330 	if (xprt_connected(xprt))
2331 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2332 
2333 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2334 			"%llu %llu %lu %llu %llu\n",
2335 			transport->srcport,
2336 			xprt->stat.bind_count,
2337 			xprt->stat.connect_count,
2338 			xprt->stat.connect_time,
2339 			idle_time,
2340 			xprt->stat.sends,
2341 			xprt->stat.recvs,
2342 			xprt->stat.bad_xids,
2343 			xprt->stat.req_u,
2344 			xprt->stat.bklog_u,
2345 			xprt->stat.max_slots,
2346 			xprt->stat.sending_u,
2347 			xprt->stat.pending_u);
2348 }
2349 
2350 /*
2351  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2352  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2353  * to use the server side send routines.
2354  */
2355 static void *bc_malloc(struct rpc_task *task, size_t size)
2356 {
2357 	struct page *page;
2358 	struct rpc_buffer *buf;
2359 
2360 	WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2361 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
2362 		return NULL;
2363 
2364 	page = alloc_page(GFP_KERNEL);
2365 	if (!page)
2366 		return NULL;
2367 
2368 	buf = page_address(page);
2369 	buf->len = PAGE_SIZE;
2370 
2371 	return buf->data;
2372 }
2373 
2374 /*
2375  * Free the space allocated in the bc_alloc routine
2376  */
2377 static void bc_free(void *buffer)
2378 {
2379 	struct rpc_buffer *buf;
2380 
2381 	if (!buffer)
2382 		return;
2383 
2384 	buf = container_of(buffer, struct rpc_buffer, data);
2385 	free_page((unsigned long)buf);
2386 }
2387 
2388 /*
2389  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2390  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2391  */
2392 static int bc_sendto(struct rpc_rqst *req)
2393 {
2394 	int len;
2395 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2396 	struct rpc_xprt *xprt = req->rq_xprt;
2397 	struct sock_xprt *transport =
2398 				container_of(xprt, struct sock_xprt, xprt);
2399 	struct socket *sock = transport->sock;
2400 	unsigned long headoff;
2401 	unsigned long tailoff;
2402 
2403 	xs_encode_stream_record_marker(xbufp);
2404 
2405 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2406 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2407 	len = svc_send_common(sock, xbufp,
2408 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2409 			      xbufp->tail[0].iov_base, tailoff);
2410 
2411 	if (len != xbufp->len) {
2412 		printk(KERN_NOTICE "Error sending entire callback!\n");
2413 		len = -EAGAIN;
2414 	}
2415 
2416 	return len;
2417 }
2418 
2419 /*
2420  * The send routine. Borrows from svc_send
2421  */
2422 static int bc_send_request(struct rpc_task *task)
2423 {
2424 	struct rpc_rqst *req = task->tk_rqstp;
2425 	struct svc_xprt	*xprt;
2426 	u32                     len;
2427 
2428 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2429 	/*
2430 	 * Get the server socket associated with this callback xprt
2431 	 */
2432 	xprt = req->rq_xprt->bc_xprt;
2433 
2434 	/*
2435 	 * Grab the mutex to serialize data as the connection is shared
2436 	 * with the fore channel
2437 	 */
2438 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2439 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2440 		if (!mutex_trylock(&xprt->xpt_mutex))
2441 			return -EAGAIN;
2442 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2443 	}
2444 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2445 		len = -ENOTCONN;
2446 	else
2447 		len = bc_sendto(req);
2448 	mutex_unlock(&xprt->xpt_mutex);
2449 
2450 	if (len > 0)
2451 		len = 0;
2452 
2453 	return len;
2454 }
2455 
2456 /*
2457  * The close routine. Since this is client initiated, we do nothing
2458  */
2459 
2460 static void bc_close(struct rpc_xprt *xprt)
2461 {
2462 }
2463 
2464 /*
2465  * The xprt destroy routine. Again, because this connection is client
2466  * initiated, we do nothing
2467  */
2468 
2469 static void bc_destroy(struct rpc_xprt *xprt)
2470 {
2471 }
2472 
2473 static struct rpc_xprt_ops xs_local_ops = {
2474 	.reserve_xprt		= xprt_reserve_xprt,
2475 	.release_xprt		= xs_tcp_release_xprt,
2476 	.alloc_slot		= xprt_alloc_slot,
2477 	.rpcbind		= xs_local_rpcbind,
2478 	.set_port		= xs_local_set_port,
2479 	.connect		= xs_local_connect,
2480 	.buf_alloc		= rpc_malloc,
2481 	.buf_free		= rpc_free,
2482 	.send_request		= xs_local_send_request,
2483 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2484 	.close			= xs_close,
2485 	.destroy		= xs_destroy,
2486 	.print_stats		= xs_local_print_stats,
2487 };
2488 
2489 static struct rpc_xprt_ops xs_udp_ops = {
2490 	.set_buffer_size	= xs_udp_set_buffer_size,
2491 	.reserve_xprt		= xprt_reserve_xprt_cong,
2492 	.release_xprt		= xprt_release_xprt_cong,
2493 	.alloc_slot		= xprt_alloc_slot,
2494 	.rpcbind		= rpcb_getport_async,
2495 	.set_port		= xs_set_port,
2496 	.connect		= xs_connect,
2497 	.buf_alloc		= rpc_malloc,
2498 	.buf_free		= rpc_free,
2499 	.send_request		= xs_udp_send_request,
2500 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2501 	.timer			= xs_udp_timer,
2502 	.release_request	= xprt_release_rqst_cong,
2503 	.close			= xs_close,
2504 	.destroy		= xs_destroy,
2505 	.print_stats		= xs_udp_print_stats,
2506 };
2507 
2508 static struct rpc_xprt_ops xs_tcp_ops = {
2509 	.reserve_xprt		= xprt_reserve_xprt,
2510 	.release_xprt		= xs_tcp_release_xprt,
2511 	.alloc_slot		= xprt_lock_and_alloc_slot,
2512 	.rpcbind		= rpcb_getport_async,
2513 	.set_port		= xs_set_port,
2514 	.connect		= xs_connect,
2515 	.buf_alloc		= rpc_malloc,
2516 	.buf_free		= rpc_free,
2517 	.send_request		= xs_tcp_send_request,
2518 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2519 	.close			= xs_tcp_close,
2520 	.destroy		= xs_destroy,
2521 	.print_stats		= xs_tcp_print_stats,
2522 };
2523 
2524 /*
2525  * The rpc_xprt_ops for the server backchannel
2526  */
2527 
2528 static struct rpc_xprt_ops bc_tcp_ops = {
2529 	.reserve_xprt		= xprt_reserve_xprt,
2530 	.release_xprt		= xprt_release_xprt,
2531 	.alloc_slot		= xprt_alloc_slot,
2532 	.rpcbind		= xs_local_rpcbind,
2533 	.buf_alloc		= bc_malloc,
2534 	.buf_free		= bc_free,
2535 	.send_request		= bc_send_request,
2536 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2537 	.close			= bc_close,
2538 	.destroy		= bc_destroy,
2539 	.print_stats		= xs_tcp_print_stats,
2540 };
2541 
2542 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2543 {
2544 	static const struct sockaddr_in sin = {
2545 		.sin_family		= AF_INET,
2546 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2547 	};
2548 	static const struct sockaddr_in6 sin6 = {
2549 		.sin6_family		= AF_INET6,
2550 		.sin6_addr		= IN6ADDR_ANY_INIT,
2551 	};
2552 
2553 	switch (family) {
2554 	case AF_LOCAL:
2555 		break;
2556 	case AF_INET:
2557 		memcpy(sap, &sin, sizeof(sin));
2558 		break;
2559 	case AF_INET6:
2560 		memcpy(sap, &sin6, sizeof(sin6));
2561 		break;
2562 	default:
2563 		dprintk("RPC:       %s: Bad address family\n", __func__);
2564 		return -EAFNOSUPPORT;
2565 	}
2566 	return 0;
2567 }
2568 
2569 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2570 				      unsigned int slot_table_size,
2571 				      unsigned int max_slot_table_size)
2572 {
2573 	struct rpc_xprt *xprt;
2574 	struct sock_xprt *new;
2575 
2576 	if (args->addrlen > sizeof(xprt->addr)) {
2577 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2578 		return ERR_PTR(-EBADF);
2579 	}
2580 
2581 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2582 			max_slot_table_size);
2583 	if (xprt == NULL) {
2584 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2585 				"rpc_xprt\n");
2586 		return ERR_PTR(-ENOMEM);
2587 	}
2588 
2589 	new = container_of(xprt, struct sock_xprt, xprt);
2590 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2591 	xprt->addrlen = args->addrlen;
2592 	if (args->srcaddr)
2593 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2594 	else {
2595 		int err;
2596 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2597 					(struct sockaddr *)&new->srcaddr);
2598 		if (err != 0) {
2599 			xprt_free(xprt);
2600 			return ERR_PTR(err);
2601 		}
2602 	}
2603 
2604 	return xprt;
2605 }
2606 
2607 static const struct rpc_timeout xs_local_default_timeout = {
2608 	.to_initval = 10 * HZ,
2609 	.to_maxval = 10 * HZ,
2610 	.to_retries = 2,
2611 };
2612 
2613 /**
2614  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2615  * @args: rpc transport creation arguments
2616  *
2617  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2618  */
2619 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2620 {
2621 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2622 	struct sock_xprt *transport;
2623 	struct rpc_xprt *xprt;
2624 	struct rpc_xprt *ret;
2625 
2626 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2627 			xprt_max_tcp_slot_table_entries);
2628 	if (IS_ERR(xprt))
2629 		return xprt;
2630 	transport = container_of(xprt, struct sock_xprt, xprt);
2631 
2632 	xprt->prot = 0;
2633 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2634 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2635 
2636 	xprt->bind_timeout = XS_BIND_TO;
2637 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2638 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2639 
2640 	xprt->ops = &xs_local_ops;
2641 	xprt->timeout = &xs_local_default_timeout;
2642 
2643 	switch (sun->sun_family) {
2644 	case AF_LOCAL:
2645 		if (sun->sun_path[0] != '/') {
2646 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2647 					sun->sun_path);
2648 			ret = ERR_PTR(-EINVAL);
2649 			goto out_err;
2650 		}
2651 		xprt_set_bound(xprt);
2652 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2653 		break;
2654 	default:
2655 		ret = ERR_PTR(-EAFNOSUPPORT);
2656 		goto out_err;
2657 	}
2658 
2659 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2660 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2661 
2662 	if (try_module_get(THIS_MODULE))
2663 		return xprt;
2664 	ret = ERR_PTR(-EINVAL);
2665 out_err:
2666 	xprt_free(xprt);
2667 	return ret;
2668 }
2669 
2670 static const struct rpc_timeout xs_udp_default_timeout = {
2671 	.to_initval = 5 * HZ,
2672 	.to_maxval = 30 * HZ,
2673 	.to_increment = 5 * HZ,
2674 	.to_retries = 5,
2675 };
2676 
2677 /**
2678  * xs_setup_udp - Set up transport to use a UDP socket
2679  * @args: rpc transport creation arguments
2680  *
2681  */
2682 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2683 {
2684 	struct sockaddr *addr = args->dstaddr;
2685 	struct rpc_xprt *xprt;
2686 	struct sock_xprt *transport;
2687 	struct rpc_xprt *ret;
2688 
2689 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2690 			xprt_udp_slot_table_entries);
2691 	if (IS_ERR(xprt))
2692 		return xprt;
2693 	transport = container_of(xprt, struct sock_xprt, xprt);
2694 
2695 	xprt->prot = IPPROTO_UDP;
2696 	xprt->tsh_size = 0;
2697 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2698 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2699 
2700 	xprt->bind_timeout = XS_BIND_TO;
2701 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2702 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2703 
2704 	xprt->ops = &xs_udp_ops;
2705 
2706 	xprt->timeout = &xs_udp_default_timeout;
2707 
2708 	switch (addr->sa_family) {
2709 	case AF_INET:
2710 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2711 			xprt_set_bound(xprt);
2712 
2713 		INIT_DELAYED_WORK(&transport->connect_worker,
2714 					xs_udp_setup_socket);
2715 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2716 		break;
2717 	case AF_INET6:
2718 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2719 			xprt_set_bound(xprt);
2720 
2721 		INIT_DELAYED_WORK(&transport->connect_worker,
2722 					xs_udp_setup_socket);
2723 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2724 		break;
2725 	default:
2726 		ret = ERR_PTR(-EAFNOSUPPORT);
2727 		goto out_err;
2728 	}
2729 
2730 	if (xprt_bound(xprt))
2731 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2732 				xprt->address_strings[RPC_DISPLAY_ADDR],
2733 				xprt->address_strings[RPC_DISPLAY_PORT],
2734 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2735 	else
2736 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2737 				xprt->address_strings[RPC_DISPLAY_ADDR],
2738 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2739 
2740 	if (try_module_get(THIS_MODULE))
2741 		return xprt;
2742 	ret = ERR_PTR(-EINVAL);
2743 out_err:
2744 	xprt_free(xprt);
2745 	return ret;
2746 }
2747 
2748 static const struct rpc_timeout xs_tcp_default_timeout = {
2749 	.to_initval = 60 * HZ,
2750 	.to_maxval = 60 * HZ,
2751 	.to_retries = 2,
2752 };
2753 
2754 /**
2755  * xs_setup_tcp - Set up transport to use a TCP socket
2756  * @args: rpc transport creation arguments
2757  *
2758  */
2759 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2760 {
2761 	struct sockaddr *addr = args->dstaddr;
2762 	struct rpc_xprt *xprt;
2763 	struct sock_xprt *transport;
2764 	struct rpc_xprt *ret;
2765 
2766 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2767 			xprt_max_tcp_slot_table_entries);
2768 	if (IS_ERR(xprt))
2769 		return xprt;
2770 	transport = container_of(xprt, struct sock_xprt, xprt);
2771 
2772 	xprt->prot = IPPROTO_TCP;
2773 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2774 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2775 
2776 	xprt->bind_timeout = XS_BIND_TO;
2777 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2778 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2779 
2780 	xprt->ops = &xs_tcp_ops;
2781 	xprt->timeout = &xs_tcp_default_timeout;
2782 
2783 	switch (addr->sa_family) {
2784 	case AF_INET:
2785 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2786 			xprt_set_bound(xprt);
2787 
2788 		INIT_DELAYED_WORK(&transport->connect_worker,
2789 					xs_tcp_setup_socket);
2790 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2791 		break;
2792 	case AF_INET6:
2793 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2794 			xprt_set_bound(xprt);
2795 
2796 		INIT_DELAYED_WORK(&transport->connect_worker,
2797 					xs_tcp_setup_socket);
2798 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2799 		break;
2800 	default:
2801 		ret = ERR_PTR(-EAFNOSUPPORT);
2802 		goto out_err;
2803 	}
2804 
2805 	if (xprt_bound(xprt))
2806 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2807 				xprt->address_strings[RPC_DISPLAY_ADDR],
2808 				xprt->address_strings[RPC_DISPLAY_PORT],
2809 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2810 	else
2811 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2812 				xprt->address_strings[RPC_DISPLAY_ADDR],
2813 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2814 
2815 
2816 	if (try_module_get(THIS_MODULE))
2817 		return xprt;
2818 	ret = ERR_PTR(-EINVAL);
2819 out_err:
2820 	xprt_free(xprt);
2821 	return ret;
2822 }
2823 
2824 /**
2825  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2826  * @args: rpc transport creation arguments
2827  *
2828  */
2829 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2830 {
2831 	struct sockaddr *addr = args->dstaddr;
2832 	struct rpc_xprt *xprt;
2833 	struct sock_xprt *transport;
2834 	struct svc_sock *bc_sock;
2835 	struct rpc_xprt *ret;
2836 
2837 	if (args->bc_xprt->xpt_bc_xprt) {
2838 		/*
2839 		 * This server connection already has a backchannel
2840 		 * export; we can't create a new one, as we wouldn't be
2841 		 * able to match replies based on xid any more.  So,
2842 		 * reuse the already-existing one:
2843 		 */
2844 		 return args->bc_xprt->xpt_bc_xprt;
2845 	}
2846 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2847 			xprt_tcp_slot_table_entries);
2848 	if (IS_ERR(xprt))
2849 		return xprt;
2850 	transport = container_of(xprt, struct sock_xprt, xprt);
2851 
2852 	xprt->prot = IPPROTO_TCP;
2853 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2854 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2855 	xprt->timeout = &xs_tcp_default_timeout;
2856 
2857 	/* backchannel */
2858 	xprt_set_bound(xprt);
2859 	xprt->bind_timeout = 0;
2860 	xprt->reestablish_timeout = 0;
2861 	xprt->idle_timeout = 0;
2862 
2863 	xprt->ops = &bc_tcp_ops;
2864 
2865 	switch (addr->sa_family) {
2866 	case AF_INET:
2867 		xs_format_peer_addresses(xprt, "tcp",
2868 					 RPCBIND_NETID_TCP);
2869 		break;
2870 	case AF_INET6:
2871 		xs_format_peer_addresses(xprt, "tcp",
2872 				   RPCBIND_NETID_TCP6);
2873 		break;
2874 	default:
2875 		ret = ERR_PTR(-EAFNOSUPPORT);
2876 		goto out_err;
2877 	}
2878 
2879 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2880 			xprt->address_strings[RPC_DISPLAY_ADDR],
2881 			xprt->address_strings[RPC_DISPLAY_PORT],
2882 			xprt->address_strings[RPC_DISPLAY_PROTO]);
2883 
2884 	/*
2885 	 * Once we've associated a backchannel xprt with a connection,
2886 	 * we want to keep it around as long as long as the connection
2887 	 * lasts, in case we need to start using it for a backchannel
2888 	 * again; this reference won't be dropped until bc_xprt is
2889 	 * destroyed.
2890 	 */
2891 	xprt_get(xprt);
2892 	args->bc_xprt->xpt_bc_xprt = xprt;
2893 	xprt->bc_xprt = args->bc_xprt;
2894 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2895 	transport->sock = bc_sock->sk_sock;
2896 	transport->inet = bc_sock->sk_sk;
2897 
2898 	/*
2899 	 * Since we don't want connections for the backchannel, we set
2900 	 * the xprt status to connected
2901 	 */
2902 	xprt_set_connected(xprt);
2903 
2904 
2905 	if (try_module_get(THIS_MODULE))
2906 		return xprt;
2907 	xprt_put(xprt);
2908 	ret = ERR_PTR(-EINVAL);
2909 out_err:
2910 	xprt_free(xprt);
2911 	return ret;
2912 }
2913 
2914 static struct xprt_class	xs_local_transport = {
2915 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
2916 	.name		= "named UNIX socket",
2917 	.owner		= THIS_MODULE,
2918 	.ident		= XPRT_TRANSPORT_LOCAL,
2919 	.setup		= xs_setup_local,
2920 };
2921 
2922 static struct xprt_class	xs_udp_transport = {
2923 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2924 	.name		= "udp",
2925 	.owner		= THIS_MODULE,
2926 	.ident		= XPRT_TRANSPORT_UDP,
2927 	.setup		= xs_setup_udp,
2928 };
2929 
2930 static struct xprt_class	xs_tcp_transport = {
2931 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2932 	.name		= "tcp",
2933 	.owner		= THIS_MODULE,
2934 	.ident		= XPRT_TRANSPORT_TCP,
2935 	.setup		= xs_setup_tcp,
2936 };
2937 
2938 static struct xprt_class	xs_bc_tcp_transport = {
2939 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2940 	.name		= "tcp NFSv4.1 backchannel",
2941 	.owner		= THIS_MODULE,
2942 	.ident		= XPRT_TRANSPORT_BC_TCP,
2943 	.setup		= xs_setup_bc_tcp,
2944 };
2945 
2946 /**
2947  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2948  *
2949  */
2950 int init_socket_xprt(void)
2951 {
2952 #ifdef RPC_DEBUG
2953 	if (!sunrpc_table_header)
2954 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2955 #endif
2956 
2957 	xprt_register_transport(&xs_local_transport);
2958 	xprt_register_transport(&xs_udp_transport);
2959 	xprt_register_transport(&xs_tcp_transport);
2960 	xprt_register_transport(&xs_bc_tcp_transport);
2961 
2962 	return 0;
2963 }
2964 
2965 /**
2966  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2967  *
2968  */
2969 void cleanup_socket_xprt(void)
2970 {
2971 #ifdef RPC_DEBUG
2972 	if (sunrpc_table_header) {
2973 		unregister_sysctl_table(sunrpc_table_header);
2974 		sunrpc_table_header = NULL;
2975 	}
2976 #endif
2977 
2978 	xprt_unregister_transport(&xs_local_transport);
2979 	xprt_unregister_transport(&xs_udp_transport);
2980 	xprt_unregister_transport(&xs_tcp_transport);
2981 	xprt_unregister_transport(&xs_bc_tcp_transport);
2982 }
2983 
2984 static int param_set_uint_minmax(const char *val,
2985 		const struct kernel_param *kp,
2986 		unsigned int min, unsigned int max)
2987 {
2988 	unsigned long num;
2989 	int ret;
2990 
2991 	if (!val)
2992 		return -EINVAL;
2993 	ret = strict_strtoul(val, 0, &num);
2994 	if (ret == -EINVAL || num < min || num > max)
2995 		return -EINVAL;
2996 	*((unsigned int *)kp->arg) = num;
2997 	return 0;
2998 }
2999 
3000 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3001 {
3002 	return param_set_uint_minmax(val, kp,
3003 			RPC_MIN_RESVPORT,
3004 			RPC_MAX_RESVPORT);
3005 }
3006 
3007 static struct kernel_param_ops param_ops_portnr = {
3008 	.set = param_set_portnr,
3009 	.get = param_get_uint,
3010 };
3011 
3012 #define param_check_portnr(name, p) \
3013 	__param_check(name, p, unsigned int);
3014 
3015 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3016 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3017 
3018 static int param_set_slot_table_size(const char *val,
3019 				     const struct kernel_param *kp)
3020 {
3021 	return param_set_uint_minmax(val, kp,
3022 			RPC_MIN_SLOT_TABLE,
3023 			RPC_MAX_SLOT_TABLE);
3024 }
3025 
3026 static struct kernel_param_ops param_ops_slot_table_size = {
3027 	.set = param_set_slot_table_size,
3028 	.get = param_get_uint,
3029 };
3030 
3031 #define param_check_slot_table_size(name, p) \
3032 	__param_check(name, p, unsigned int);
3033 
3034 static int param_set_max_slot_table_size(const char *val,
3035 				     const struct kernel_param *kp)
3036 {
3037 	return param_set_uint_minmax(val, kp,
3038 			RPC_MIN_SLOT_TABLE,
3039 			RPC_MAX_SLOT_TABLE_LIMIT);
3040 }
3041 
3042 static struct kernel_param_ops param_ops_max_slot_table_size = {
3043 	.set = param_set_max_slot_table_size,
3044 	.get = param_get_uint,
3045 };
3046 
3047 #define param_check_max_slot_table_size(name, p) \
3048 	__param_check(name, p, unsigned int);
3049 
3050 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3051 		   slot_table_size, 0644);
3052 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3053 		   max_slot_table_size, 0644);
3054 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3055 		   slot_table_size, 0644);
3056 
3057