xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision b6bec26c)
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/sched.h>
37 #include <linux/sunrpc/svcsock.h>
38 #include <linux/sunrpc/xprtsock.h>
39 #include <linux/file.h>
40 #ifdef CONFIG_SUNRPC_BACKCHANNEL
41 #include <linux/sunrpc/bc_xprt.h>
42 #endif
43 
44 #include <net/sock.h>
45 #include <net/checksum.h>
46 #include <net/udp.h>
47 #include <net/tcp.h>
48 
49 #include "sunrpc.h"
50 
51 static void xs_close(struct rpc_xprt *xprt);
52 
53 /*
54  * xprtsock tunables
55  */
56 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
57 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
58 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
59 
60 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
61 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
62 
63 #define XS_TCP_LINGER_TO	(15U * HZ)
64 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
65 
66 /*
67  * We can register our own files under /proc/sys/sunrpc by
68  * calling register_sysctl_table() again.  The files in that
69  * directory become the union of all files registered there.
70  *
71  * We simply need to make sure that we don't collide with
72  * someone else's file names!
73  */
74 
75 #ifdef RPC_DEBUG
76 
77 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
78 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
79 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
80 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
81 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
82 
83 static struct ctl_table_header *sunrpc_table_header;
84 
85 /*
86  * FIXME: changing the UDP slot table size should also resize the UDP
87  *        socket buffers for existing UDP transports
88  */
89 static ctl_table xs_tunables_table[] = {
90 	{
91 		.procname	= "udp_slot_table_entries",
92 		.data		= &xprt_udp_slot_table_entries,
93 		.maxlen		= sizeof(unsigned int),
94 		.mode		= 0644,
95 		.proc_handler	= proc_dointvec_minmax,
96 		.extra1		= &min_slot_table_size,
97 		.extra2		= &max_slot_table_size
98 	},
99 	{
100 		.procname	= "tcp_slot_table_entries",
101 		.data		= &xprt_tcp_slot_table_entries,
102 		.maxlen		= sizeof(unsigned int),
103 		.mode		= 0644,
104 		.proc_handler	= proc_dointvec_minmax,
105 		.extra1		= &min_slot_table_size,
106 		.extra2		= &max_slot_table_size
107 	},
108 	{
109 		.procname	= "tcp_max_slot_table_entries",
110 		.data		= &xprt_max_tcp_slot_table_entries,
111 		.maxlen		= sizeof(unsigned int),
112 		.mode		= 0644,
113 		.proc_handler	= proc_dointvec_minmax,
114 		.extra1		= &min_slot_table_size,
115 		.extra2		= &max_tcp_slot_table_limit
116 	},
117 	{
118 		.procname	= "min_resvport",
119 		.data		= &xprt_min_resvport,
120 		.maxlen		= sizeof(unsigned int),
121 		.mode		= 0644,
122 		.proc_handler	= proc_dointvec_minmax,
123 		.extra1		= &xprt_min_resvport_limit,
124 		.extra2		= &xprt_max_resvport_limit
125 	},
126 	{
127 		.procname	= "max_resvport",
128 		.data		= &xprt_max_resvport,
129 		.maxlen		= sizeof(unsigned int),
130 		.mode		= 0644,
131 		.proc_handler	= proc_dointvec_minmax,
132 		.extra1		= &xprt_min_resvport_limit,
133 		.extra2		= &xprt_max_resvport_limit
134 	},
135 	{
136 		.procname	= "tcp_fin_timeout",
137 		.data		= &xs_tcp_fin_timeout,
138 		.maxlen		= sizeof(xs_tcp_fin_timeout),
139 		.mode		= 0644,
140 		.proc_handler	= proc_dointvec_jiffies,
141 	},
142 	{ },
143 };
144 
145 static ctl_table sunrpc_table[] = {
146 	{
147 		.procname	= "sunrpc",
148 		.mode		= 0555,
149 		.child		= xs_tunables_table
150 	},
151 	{ },
152 };
153 
154 #endif
155 
156 /*
157  * Wait duration for a reply from the RPC portmapper.
158  */
159 #define XS_BIND_TO		(60U * HZ)
160 
161 /*
162  * Delay if a UDP socket connect error occurs.  This is most likely some
163  * kind of resource problem on the local host.
164  */
165 #define XS_UDP_REEST_TO		(2U * HZ)
166 
167 /*
168  * The reestablish timeout allows clients to delay for a bit before attempting
169  * to reconnect to a server that just dropped our connection.
170  *
171  * We implement an exponential backoff when trying to reestablish a TCP
172  * transport connection with the server.  Some servers like to drop a TCP
173  * connection when they are overworked, so we start with a short timeout and
174  * increase over time if the server is down or not responding.
175  */
176 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
177 #define XS_TCP_MAX_REEST_TO	(5U * 60 * HZ)
178 
179 /*
180  * TCP idle timeout; client drops the transport socket if it is idle
181  * for this long.  Note that we also timeout UDP sockets to prevent
182  * holding port numbers when there is no RPC traffic.
183  */
184 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
185 
186 #ifdef RPC_DEBUG
187 # undef  RPC_DEBUG_DATA
188 # define RPCDBG_FACILITY	RPCDBG_TRANS
189 #endif
190 
191 #ifdef RPC_DEBUG_DATA
192 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
193 {
194 	u8 *buf = (u8 *) packet;
195 	int j;
196 
197 	dprintk("RPC:       %s\n", msg);
198 	for (j = 0; j < count && j < 128; j += 4) {
199 		if (!(j & 31)) {
200 			if (j)
201 				dprintk("\n");
202 			dprintk("0x%04x ", j);
203 		}
204 		dprintk("%02x%02x%02x%02x ",
205 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
206 	}
207 	dprintk("\n");
208 }
209 #else
210 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
211 {
212 	/* NOP */
213 }
214 #endif
215 
216 struct sock_xprt {
217 	struct rpc_xprt		xprt;
218 
219 	/*
220 	 * Network layer
221 	 */
222 	struct socket *		sock;
223 	struct sock *		inet;
224 
225 	/*
226 	 * State of TCP reply receive
227 	 */
228 	__be32			tcp_fraghdr,
229 				tcp_xid,
230 				tcp_calldir;
231 
232 	u32			tcp_offset,
233 				tcp_reclen;
234 
235 	unsigned long		tcp_copied,
236 				tcp_flags;
237 
238 	/*
239 	 * Connection of transports
240 	 */
241 	struct delayed_work	connect_worker;
242 	struct sockaddr_storage	srcaddr;
243 	unsigned short		srcport;
244 
245 	/*
246 	 * UDP socket buffer size parameters
247 	 */
248 	size_t			rcvsize,
249 				sndsize;
250 
251 	/*
252 	 * Saved socket callback addresses
253 	 */
254 	void			(*old_data_ready)(struct sock *, int);
255 	void			(*old_state_change)(struct sock *);
256 	void			(*old_write_space)(struct sock *);
257 };
258 
259 /*
260  * TCP receive state flags
261  */
262 #define TCP_RCV_LAST_FRAG	(1UL << 0)
263 #define TCP_RCV_COPY_FRAGHDR	(1UL << 1)
264 #define TCP_RCV_COPY_XID	(1UL << 2)
265 #define TCP_RCV_COPY_DATA	(1UL << 3)
266 #define TCP_RCV_READ_CALLDIR	(1UL << 4)
267 #define TCP_RCV_COPY_CALLDIR	(1UL << 5)
268 
269 /*
270  * TCP RPC flags
271  */
272 #define TCP_RPC_REPLY		(1UL << 6)
273 
274 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
275 {
276 	return (struct sockaddr *) &xprt->addr;
277 }
278 
279 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
280 {
281 	return (struct sockaddr_un *) &xprt->addr;
282 }
283 
284 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
285 {
286 	return (struct sockaddr_in *) &xprt->addr;
287 }
288 
289 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
290 {
291 	return (struct sockaddr_in6 *) &xprt->addr;
292 }
293 
294 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
295 {
296 	struct sockaddr *sap = xs_addr(xprt);
297 	struct sockaddr_in6 *sin6;
298 	struct sockaddr_in *sin;
299 	struct sockaddr_un *sun;
300 	char buf[128];
301 
302 	switch (sap->sa_family) {
303 	case AF_LOCAL:
304 		sun = xs_addr_un(xprt);
305 		strlcpy(buf, sun->sun_path, sizeof(buf));
306 		xprt->address_strings[RPC_DISPLAY_ADDR] =
307 						kstrdup(buf, GFP_KERNEL);
308 		break;
309 	case AF_INET:
310 		(void)rpc_ntop(sap, buf, sizeof(buf));
311 		xprt->address_strings[RPC_DISPLAY_ADDR] =
312 						kstrdup(buf, GFP_KERNEL);
313 		sin = xs_addr_in(xprt);
314 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
315 		break;
316 	case AF_INET6:
317 		(void)rpc_ntop(sap, buf, sizeof(buf));
318 		xprt->address_strings[RPC_DISPLAY_ADDR] =
319 						kstrdup(buf, GFP_KERNEL);
320 		sin6 = xs_addr_in6(xprt);
321 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
322 		break;
323 	default:
324 		BUG();
325 	}
326 
327 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
328 }
329 
330 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
331 {
332 	struct sockaddr *sap = xs_addr(xprt);
333 	char buf[128];
334 
335 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
336 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
337 
338 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
339 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
340 }
341 
342 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
343 				     const char *protocol,
344 				     const char *netid)
345 {
346 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
347 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
348 	xs_format_common_peer_addresses(xprt);
349 	xs_format_common_peer_ports(xprt);
350 }
351 
352 static void xs_update_peer_port(struct rpc_xprt *xprt)
353 {
354 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
355 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
356 
357 	xs_format_common_peer_ports(xprt);
358 }
359 
360 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
361 {
362 	unsigned int i;
363 
364 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
365 		switch (i) {
366 		case RPC_DISPLAY_PROTO:
367 		case RPC_DISPLAY_NETID:
368 			continue;
369 		default:
370 			kfree(xprt->address_strings[i]);
371 		}
372 }
373 
374 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
375 
376 static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
377 {
378 	struct msghdr msg = {
379 		.msg_name	= addr,
380 		.msg_namelen	= addrlen,
381 		.msg_flags	= XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
382 	};
383 	struct kvec iov = {
384 		.iov_base	= vec->iov_base + base,
385 		.iov_len	= vec->iov_len - base,
386 	};
387 
388 	if (iov.iov_len != 0)
389 		return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
390 	return kernel_sendmsg(sock, &msg, NULL, 0, 0);
391 }
392 
393 static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more)
394 {
395 	struct page **ppage;
396 	unsigned int remainder;
397 	int err, sent = 0;
398 
399 	remainder = xdr->page_len - base;
400 	base += xdr->page_base;
401 	ppage = xdr->pages + (base >> PAGE_SHIFT);
402 	base &= ~PAGE_MASK;
403 	for(;;) {
404 		unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
405 		int flags = XS_SENDMSG_FLAGS;
406 
407 		remainder -= len;
408 		if (remainder != 0 || more)
409 			flags |= MSG_MORE;
410 		err = sock->ops->sendpage(sock, *ppage, base, len, flags);
411 		if (remainder == 0 || err != len)
412 			break;
413 		sent += err;
414 		ppage++;
415 		base = 0;
416 	}
417 	if (sent == 0)
418 		return err;
419 	if (err > 0)
420 		sent += err;
421 	return sent;
422 }
423 
424 /**
425  * xs_sendpages - write pages directly to a socket
426  * @sock: socket to send on
427  * @addr: UDP only -- address of destination
428  * @addrlen: UDP only -- length of destination address
429  * @xdr: buffer containing this request
430  * @base: starting position in the buffer
431  *
432  */
433 static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
434 {
435 	unsigned int remainder = xdr->len - base;
436 	int err, sent = 0;
437 
438 	if (unlikely(!sock))
439 		return -ENOTSOCK;
440 
441 	clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
442 	if (base != 0) {
443 		addr = NULL;
444 		addrlen = 0;
445 	}
446 
447 	if (base < xdr->head[0].iov_len || addr != NULL) {
448 		unsigned int len = xdr->head[0].iov_len - base;
449 		remainder -= len;
450 		err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
451 		if (remainder == 0 || err != len)
452 			goto out;
453 		sent += err;
454 		base = 0;
455 	} else
456 		base -= xdr->head[0].iov_len;
457 
458 	if (base < xdr->page_len) {
459 		unsigned int len = xdr->page_len - base;
460 		remainder -= len;
461 		err = xs_send_pagedata(sock, xdr, base, remainder != 0);
462 		if (remainder == 0 || err != len)
463 			goto out;
464 		sent += err;
465 		base = 0;
466 	} else
467 		base -= xdr->page_len;
468 
469 	if (base >= xdr->tail[0].iov_len)
470 		return sent;
471 	err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
472 out:
473 	if (sent == 0)
474 		return err;
475 	if (err > 0)
476 		sent += err;
477 	return sent;
478 }
479 
480 static void xs_nospace_callback(struct rpc_task *task)
481 {
482 	struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
483 
484 	transport->inet->sk_write_pending--;
485 	clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
486 }
487 
488 /**
489  * xs_nospace - place task on wait queue if transmit was incomplete
490  * @task: task to put to sleep
491  *
492  */
493 static int xs_nospace(struct rpc_task *task)
494 {
495 	struct rpc_rqst *req = task->tk_rqstp;
496 	struct rpc_xprt *xprt = req->rq_xprt;
497 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
498 	int ret = -EAGAIN;
499 
500 	dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
501 			task->tk_pid, req->rq_slen - req->rq_bytes_sent,
502 			req->rq_slen);
503 
504 	/* Protect against races with write_space */
505 	spin_lock_bh(&xprt->transport_lock);
506 
507 	/* Don't race with disconnect */
508 	if (xprt_connected(xprt)) {
509 		if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
510 			/*
511 			 * Notify TCP that we're limited by the application
512 			 * window size
513 			 */
514 			set_bit(SOCK_NOSPACE, &transport->sock->flags);
515 			transport->inet->sk_write_pending++;
516 			/* ...and wait for more buffer space */
517 			xprt_wait_for_buffer_space(task, xs_nospace_callback);
518 		}
519 	} else {
520 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
521 		ret = -ENOTCONN;
522 	}
523 
524 	spin_unlock_bh(&xprt->transport_lock);
525 	return ret;
526 }
527 
528 /*
529  * Construct a stream transport record marker in @buf.
530  */
531 static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
532 {
533 	u32 reclen = buf->len - sizeof(rpc_fraghdr);
534 	rpc_fraghdr *base = buf->head[0].iov_base;
535 	*base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
536 }
537 
538 /**
539  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
540  * @task: RPC task that manages the state of an RPC request
541  *
542  * Return values:
543  *        0:	The request has been sent
544  *   EAGAIN:	The socket was blocked, please call again later to
545  *		complete the request
546  * ENOTCONN:	Caller needs to invoke connect logic then call again
547  *    other:	Some other error occured, the request was not sent
548  */
549 static int xs_local_send_request(struct rpc_task *task)
550 {
551 	struct rpc_rqst *req = task->tk_rqstp;
552 	struct rpc_xprt *xprt = req->rq_xprt;
553 	struct sock_xprt *transport =
554 				container_of(xprt, struct sock_xprt, xprt);
555 	struct xdr_buf *xdr = &req->rq_snd_buf;
556 	int status;
557 
558 	xs_encode_stream_record_marker(&req->rq_snd_buf);
559 
560 	xs_pktdump("packet data:",
561 			req->rq_svec->iov_base, req->rq_svec->iov_len);
562 
563 	status = xs_sendpages(transport->sock, NULL, 0,
564 						xdr, req->rq_bytes_sent);
565 	dprintk("RPC:       %s(%u) = %d\n",
566 			__func__, xdr->len - req->rq_bytes_sent, status);
567 	if (likely(status >= 0)) {
568 		req->rq_bytes_sent += status;
569 		req->rq_xmit_bytes_sent += status;
570 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
571 			req->rq_bytes_sent = 0;
572 			return 0;
573 		}
574 		status = -EAGAIN;
575 	}
576 
577 	switch (status) {
578 	case -EAGAIN:
579 		status = xs_nospace(task);
580 		break;
581 	default:
582 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
583 			-status);
584 	case -EPIPE:
585 		xs_close(xprt);
586 		status = -ENOTCONN;
587 	}
588 
589 	return status;
590 }
591 
592 /**
593  * xs_udp_send_request - write an RPC request to a UDP socket
594  * @task: address of RPC task that manages the state of an RPC request
595  *
596  * Return values:
597  *        0:	The request has been sent
598  *   EAGAIN:	The socket was blocked, please call again later to
599  *		complete the request
600  * ENOTCONN:	Caller needs to invoke connect logic then call again
601  *    other:	Some other error occurred, the request was not sent
602  */
603 static int xs_udp_send_request(struct rpc_task *task)
604 {
605 	struct rpc_rqst *req = task->tk_rqstp;
606 	struct rpc_xprt *xprt = req->rq_xprt;
607 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
608 	struct xdr_buf *xdr = &req->rq_snd_buf;
609 	int status;
610 
611 	xs_pktdump("packet data:",
612 				req->rq_svec->iov_base,
613 				req->rq_svec->iov_len);
614 
615 	if (!xprt_bound(xprt))
616 		return -ENOTCONN;
617 	status = xs_sendpages(transport->sock,
618 			      xs_addr(xprt),
619 			      xprt->addrlen, xdr,
620 			      req->rq_bytes_sent);
621 
622 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
623 			xdr->len - req->rq_bytes_sent, status);
624 
625 	if (status >= 0) {
626 		req->rq_xmit_bytes_sent += status;
627 		if (status >= req->rq_slen)
628 			return 0;
629 		/* Still some bytes left; set up for a retry later. */
630 		status = -EAGAIN;
631 	}
632 
633 	switch (status) {
634 	case -ENOTSOCK:
635 		status = -ENOTCONN;
636 		/* Should we call xs_close() here? */
637 		break;
638 	case -EAGAIN:
639 		status = xs_nospace(task);
640 		break;
641 	default:
642 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
643 			-status);
644 	case -ENETUNREACH:
645 	case -EPIPE:
646 	case -ECONNREFUSED:
647 		/* When the server has died, an ICMP port unreachable message
648 		 * prompts ECONNREFUSED. */
649 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
650 	}
651 
652 	return status;
653 }
654 
655 /**
656  * xs_tcp_shutdown - gracefully shut down a TCP socket
657  * @xprt: transport
658  *
659  * Initiates a graceful shutdown of the TCP socket by calling the
660  * equivalent of shutdown(SHUT_WR);
661  */
662 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
663 {
664 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
665 	struct socket *sock = transport->sock;
666 
667 	if (sock != NULL)
668 		kernel_sock_shutdown(sock, SHUT_WR);
669 }
670 
671 /**
672  * xs_tcp_send_request - write an RPC request to a TCP socket
673  * @task: address of RPC task that manages the state of an RPC request
674  *
675  * Return values:
676  *        0:	The request has been sent
677  *   EAGAIN:	The socket was blocked, please call again later to
678  *		complete the request
679  * ENOTCONN:	Caller needs to invoke connect logic then call again
680  *    other:	Some other error occurred, the request was not sent
681  *
682  * XXX: In the case of soft timeouts, should we eventually give up
683  *	if sendmsg is not able to make progress?
684  */
685 static int xs_tcp_send_request(struct rpc_task *task)
686 {
687 	struct rpc_rqst *req = task->tk_rqstp;
688 	struct rpc_xprt *xprt = req->rq_xprt;
689 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
690 	struct xdr_buf *xdr = &req->rq_snd_buf;
691 	int status;
692 
693 	xs_encode_stream_record_marker(&req->rq_snd_buf);
694 
695 	xs_pktdump("packet data:",
696 				req->rq_svec->iov_base,
697 				req->rq_svec->iov_len);
698 
699 	/* Continue transmitting the packet/record. We must be careful
700 	 * to cope with writespace callbacks arriving _after_ we have
701 	 * called sendmsg(). */
702 	while (1) {
703 		status = xs_sendpages(transport->sock,
704 					NULL, 0, xdr, req->rq_bytes_sent);
705 
706 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
707 				xdr->len - req->rq_bytes_sent, status);
708 
709 		if (unlikely(status < 0))
710 			break;
711 
712 		/* If we've sent the entire packet, immediately
713 		 * reset the count of bytes sent. */
714 		req->rq_bytes_sent += status;
715 		req->rq_xmit_bytes_sent += status;
716 		if (likely(req->rq_bytes_sent >= req->rq_slen)) {
717 			req->rq_bytes_sent = 0;
718 			return 0;
719 		}
720 
721 		if (status != 0)
722 			continue;
723 		status = -EAGAIN;
724 		break;
725 	}
726 
727 	switch (status) {
728 	case -ENOTSOCK:
729 		status = -ENOTCONN;
730 		/* Should we call xs_close() here? */
731 		break;
732 	case -EAGAIN:
733 		status = xs_nospace(task);
734 		break;
735 	default:
736 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
737 			-status);
738 	case -ECONNRESET:
739 		xs_tcp_shutdown(xprt);
740 	case -ECONNREFUSED:
741 	case -ENOTCONN:
742 	case -EPIPE:
743 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
744 	}
745 
746 	return status;
747 }
748 
749 /**
750  * xs_tcp_release_xprt - clean up after a tcp transmission
751  * @xprt: transport
752  * @task: rpc task
753  *
754  * This cleans up if an error causes us to abort the transmission of a request.
755  * In this case, the socket may need to be reset in order to avoid confusing
756  * the server.
757  */
758 static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
759 {
760 	struct rpc_rqst *req;
761 
762 	if (task != xprt->snd_task)
763 		return;
764 	if (task == NULL)
765 		goto out_release;
766 	req = task->tk_rqstp;
767 	if (req == NULL)
768 		goto out_release;
769 	if (req->rq_bytes_sent == 0)
770 		goto out_release;
771 	if (req->rq_bytes_sent == req->rq_snd_buf.len)
772 		goto out_release;
773 	set_bit(XPRT_CLOSE_WAIT, &task->tk_xprt->state);
774 out_release:
775 	xprt_release_xprt(xprt, task);
776 }
777 
778 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
779 {
780 	transport->old_data_ready = sk->sk_data_ready;
781 	transport->old_state_change = sk->sk_state_change;
782 	transport->old_write_space = sk->sk_write_space;
783 }
784 
785 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
786 {
787 	sk->sk_data_ready = transport->old_data_ready;
788 	sk->sk_state_change = transport->old_state_change;
789 	sk->sk_write_space = transport->old_write_space;
790 }
791 
792 static void xs_reset_transport(struct sock_xprt *transport)
793 {
794 	struct socket *sock = transport->sock;
795 	struct sock *sk = transport->inet;
796 
797 	if (sk == NULL)
798 		return;
799 
800 	transport->srcport = 0;
801 
802 	write_lock_bh(&sk->sk_callback_lock);
803 	transport->inet = NULL;
804 	transport->sock = NULL;
805 
806 	sk->sk_user_data = NULL;
807 
808 	xs_restore_old_callbacks(transport, sk);
809 	write_unlock_bh(&sk->sk_callback_lock);
810 
811 	sk->sk_no_check = 0;
812 
813 	sock_release(sock);
814 }
815 
816 /**
817  * xs_close - close a socket
818  * @xprt: transport
819  *
820  * This is used when all requests are complete; ie, no DRC state remains
821  * on the server we want to save.
822  *
823  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
824  * xs_reset_transport() zeroing the socket from underneath a writer.
825  */
826 static void xs_close(struct rpc_xprt *xprt)
827 {
828 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
829 
830 	dprintk("RPC:       xs_close xprt %p\n", xprt);
831 
832 	xs_reset_transport(transport);
833 	xprt->reestablish_timeout = 0;
834 
835 	smp_mb__before_clear_bit();
836 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
837 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
838 	clear_bit(XPRT_CLOSING, &xprt->state);
839 	smp_mb__after_clear_bit();
840 	xprt_disconnect_done(xprt);
841 }
842 
843 static void xs_tcp_close(struct rpc_xprt *xprt)
844 {
845 	if (test_and_clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state))
846 		xs_close(xprt);
847 	else
848 		xs_tcp_shutdown(xprt);
849 }
850 
851 /**
852  * xs_destroy - prepare to shutdown a transport
853  * @xprt: doomed transport
854  *
855  */
856 static void xs_destroy(struct rpc_xprt *xprt)
857 {
858 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
859 
860 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
861 
862 	cancel_delayed_work_sync(&transport->connect_worker);
863 
864 	xs_close(xprt);
865 	xs_free_peer_addresses(xprt);
866 	xprt_free(xprt);
867 	module_put(THIS_MODULE);
868 }
869 
870 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
871 {
872 	return (struct rpc_xprt *) sk->sk_user_data;
873 }
874 
875 static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
876 {
877 	struct xdr_skb_reader desc = {
878 		.skb		= skb,
879 		.offset		= sizeof(rpc_fraghdr),
880 		.count		= skb->len - sizeof(rpc_fraghdr),
881 	};
882 
883 	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
884 		return -1;
885 	if (desc.count)
886 		return -1;
887 	return 0;
888 }
889 
890 /**
891  * xs_local_data_ready - "data ready" callback for AF_LOCAL sockets
892  * @sk: socket with data to read
893  * @len: how much data to read
894  *
895  * Currently this assumes we can read the whole reply in a single gulp.
896  */
897 static void xs_local_data_ready(struct sock *sk, int len)
898 {
899 	struct rpc_task *task;
900 	struct rpc_xprt *xprt;
901 	struct rpc_rqst *rovr;
902 	struct sk_buff *skb;
903 	int err, repsize, copied;
904 	u32 _xid;
905 	__be32 *xp;
906 
907 	read_lock_bh(&sk->sk_callback_lock);
908 	dprintk("RPC:       %s...\n", __func__);
909 	xprt = xprt_from_sock(sk);
910 	if (xprt == NULL)
911 		goto out;
912 
913 	skb = skb_recv_datagram(sk, 0, 1, &err);
914 	if (skb == NULL)
915 		goto out;
916 
917 	repsize = skb->len - sizeof(rpc_fraghdr);
918 	if (repsize < 4) {
919 		dprintk("RPC:       impossible RPC reply size %d\n", repsize);
920 		goto dropit;
921 	}
922 
923 	/* Copy the XID from the skb... */
924 	xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
925 	if (xp == NULL)
926 		goto dropit;
927 
928 	/* Look up and lock the request corresponding to the given XID */
929 	spin_lock(&xprt->transport_lock);
930 	rovr = xprt_lookup_rqst(xprt, *xp);
931 	if (!rovr)
932 		goto out_unlock;
933 	task = rovr->rq_task;
934 
935 	copied = rovr->rq_private_buf.buflen;
936 	if (copied > repsize)
937 		copied = repsize;
938 
939 	if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
940 		dprintk("RPC:       sk_buff copy failed\n");
941 		goto out_unlock;
942 	}
943 
944 	xprt_complete_rqst(task, copied);
945 
946  out_unlock:
947 	spin_unlock(&xprt->transport_lock);
948  dropit:
949 	skb_free_datagram(sk, skb);
950  out:
951 	read_unlock_bh(&sk->sk_callback_lock);
952 }
953 
954 /**
955  * xs_udp_data_ready - "data ready" callback for UDP sockets
956  * @sk: socket with data to read
957  * @len: how much data to read
958  *
959  */
960 static void xs_udp_data_ready(struct sock *sk, int len)
961 {
962 	struct rpc_task *task;
963 	struct rpc_xprt *xprt;
964 	struct rpc_rqst *rovr;
965 	struct sk_buff *skb;
966 	int err, repsize, copied;
967 	u32 _xid;
968 	__be32 *xp;
969 
970 	read_lock_bh(&sk->sk_callback_lock);
971 	dprintk("RPC:       xs_udp_data_ready...\n");
972 	if (!(xprt = xprt_from_sock(sk)))
973 		goto out;
974 
975 	if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
976 		goto out;
977 
978 	repsize = skb->len - sizeof(struct udphdr);
979 	if (repsize < 4) {
980 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
981 		goto dropit;
982 	}
983 
984 	/* Copy the XID from the skb... */
985 	xp = skb_header_pointer(skb, sizeof(struct udphdr),
986 				sizeof(_xid), &_xid);
987 	if (xp == NULL)
988 		goto dropit;
989 
990 	/* Look up and lock the request corresponding to the given XID */
991 	spin_lock(&xprt->transport_lock);
992 	rovr = xprt_lookup_rqst(xprt, *xp);
993 	if (!rovr)
994 		goto out_unlock;
995 	task = rovr->rq_task;
996 
997 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
998 		copied = repsize;
999 
1000 	/* Suck it into the iovec, verify checksum if not done by hw. */
1001 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1002 		UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
1003 		goto out_unlock;
1004 	}
1005 
1006 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
1007 
1008 	xprt_adjust_cwnd(task, copied);
1009 	xprt_complete_rqst(task, copied);
1010 
1011  out_unlock:
1012 	spin_unlock(&xprt->transport_lock);
1013  dropit:
1014 	skb_free_datagram(sk, skb);
1015  out:
1016 	read_unlock_bh(&sk->sk_callback_lock);
1017 }
1018 
1019 /*
1020  * Helper function to force a TCP close if the server is sending
1021  * junk and/or it has put us in CLOSE_WAIT
1022  */
1023 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1024 {
1025 	set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1026 	xprt_force_disconnect(xprt);
1027 }
1028 
1029 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
1030 {
1031 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1032 	size_t len, used;
1033 	char *p;
1034 
1035 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
1036 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
1037 	used = xdr_skb_read_bits(desc, p, len);
1038 	transport->tcp_offset += used;
1039 	if (used != len)
1040 		return;
1041 
1042 	transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
1043 	if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
1044 		transport->tcp_flags |= TCP_RCV_LAST_FRAG;
1045 	else
1046 		transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
1047 	transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
1048 
1049 	transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
1050 	transport->tcp_offset = 0;
1051 
1052 	/* Sanity check of the record length */
1053 	if (unlikely(transport->tcp_reclen < 8)) {
1054 		dprintk("RPC:       invalid TCP record fragment length\n");
1055 		xs_tcp_force_close(xprt);
1056 		return;
1057 	}
1058 	dprintk("RPC:       reading TCP record fragment of length %d\n",
1059 			transport->tcp_reclen);
1060 }
1061 
1062 static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
1063 {
1064 	if (transport->tcp_offset == transport->tcp_reclen) {
1065 		transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
1066 		transport->tcp_offset = 0;
1067 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
1068 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1069 			transport->tcp_flags |= TCP_RCV_COPY_XID;
1070 			transport->tcp_copied = 0;
1071 		}
1072 	}
1073 }
1074 
1075 static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1076 {
1077 	size_t len, used;
1078 	char *p;
1079 
1080 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
1081 	dprintk("RPC:       reading XID (%Zu bytes)\n", len);
1082 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
1083 	used = xdr_skb_read_bits(desc, p, len);
1084 	transport->tcp_offset += used;
1085 	if (used != len)
1086 		return;
1087 	transport->tcp_flags &= ~TCP_RCV_COPY_XID;
1088 	transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
1089 	transport->tcp_copied = 4;
1090 	dprintk("RPC:       reading %s XID %08x\n",
1091 			(transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
1092 							      : "request with",
1093 			ntohl(transport->tcp_xid));
1094 	xs_tcp_check_fraghdr(transport);
1095 }
1096 
1097 static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
1098 				       struct xdr_skb_reader *desc)
1099 {
1100 	size_t len, used;
1101 	u32 offset;
1102 	char *p;
1103 
1104 	/*
1105 	 * We want transport->tcp_offset to be 8 at the end of this routine
1106 	 * (4 bytes for the xid and 4 bytes for the call/reply flag).
1107 	 * When this function is called for the first time,
1108 	 * transport->tcp_offset is 4 (after having already read the xid).
1109 	 */
1110 	offset = transport->tcp_offset - sizeof(transport->tcp_xid);
1111 	len = sizeof(transport->tcp_calldir) - offset;
1112 	dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
1113 	p = ((char *) &transport->tcp_calldir) + offset;
1114 	used = xdr_skb_read_bits(desc, p, len);
1115 	transport->tcp_offset += used;
1116 	if (used != len)
1117 		return;
1118 	transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
1119 	/*
1120 	 * We don't yet have the XDR buffer, so we will write the calldir
1121 	 * out after we get the buffer from the 'struct rpc_rqst'
1122 	 */
1123 	switch (ntohl(transport->tcp_calldir)) {
1124 	case RPC_REPLY:
1125 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1126 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1127 		transport->tcp_flags |= TCP_RPC_REPLY;
1128 		break;
1129 	case RPC_CALL:
1130 		transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
1131 		transport->tcp_flags |= TCP_RCV_COPY_DATA;
1132 		transport->tcp_flags &= ~TCP_RPC_REPLY;
1133 		break;
1134 	default:
1135 		dprintk("RPC:       invalid request message type\n");
1136 		xs_tcp_force_close(&transport->xprt);
1137 	}
1138 	xs_tcp_check_fraghdr(transport);
1139 }
1140 
1141 static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
1142 				     struct xdr_skb_reader *desc,
1143 				     struct rpc_rqst *req)
1144 {
1145 	struct sock_xprt *transport =
1146 				container_of(xprt, struct sock_xprt, xprt);
1147 	struct xdr_buf *rcvbuf;
1148 	size_t len;
1149 	ssize_t r;
1150 
1151 	rcvbuf = &req->rq_private_buf;
1152 
1153 	if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
1154 		/*
1155 		 * Save the RPC direction in the XDR buffer
1156 		 */
1157 		memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
1158 			&transport->tcp_calldir,
1159 			sizeof(transport->tcp_calldir));
1160 		transport->tcp_copied += sizeof(transport->tcp_calldir);
1161 		transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
1162 	}
1163 
1164 	len = desc->count;
1165 	if (len > transport->tcp_reclen - transport->tcp_offset) {
1166 		struct xdr_skb_reader my_desc;
1167 
1168 		len = transport->tcp_reclen - transport->tcp_offset;
1169 		memcpy(&my_desc, desc, sizeof(my_desc));
1170 		my_desc.count = len;
1171 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1172 					  &my_desc, xdr_skb_read_bits);
1173 		desc->count -= r;
1174 		desc->offset += r;
1175 	} else
1176 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
1177 					  desc, xdr_skb_read_bits);
1178 
1179 	if (r > 0) {
1180 		transport->tcp_copied += r;
1181 		transport->tcp_offset += r;
1182 	}
1183 	if (r != len) {
1184 		/* Error when copying to the receive buffer,
1185 		 * usually because we weren't able to allocate
1186 		 * additional buffer pages. All we can do now
1187 		 * is turn off TCP_RCV_COPY_DATA, so the request
1188 		 * will not receive any additional updates,
1189 		 * and time out.
1190 		 * Any remaining data from this record will
1191 		 * be discarded.
1192 		 */
1193 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1194 		dprintk("RPC:       XID %08x truncated request\n",
1195 				ntohl(transport->tcp_xid));
1196 		dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
1197 				"tcp_offset = %u, tcp_reclen = %u\n",
1198 				xprt, transport->tcp_copied,
1199 				transport->tcp_offset, transport->tcp_reclen);
1200 		return;
1201 	}
1202 
1203 	dprintk("RPC:       XID %08x read %Zd bytes\n",
1204 			ntohl(transport->tcp_xid), r);
1205 	dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
1206 			"tcp_reclen = %u\n", xprt, transport->tcp_copied,
1207 			transport->tcp_offset, transport->tcp_reclen);
1208 
1209 	if (transport->tcp_copied == req->rq_private_buf.buflen)
1210 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1211 	else if (transport->tcp_offset == transport->tcp_reclen) {
1212 		if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
1213 			transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1214 	}
1215 }
1216 
1217 /*
1218  * Finds the request corresponding to the RPC xid and invokes the common
1219  * tcp read code to read the data.
1220  */
1221 static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
1222 				    struct xdr_skb_reader *desc)
1223 {
1224 	struct sock_xprt *transport =
1225 				container_of(xprt, struct sock_xprt, xprt);
1226 	struct rpc_rqst *req;
1227 
1228 	dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
1229 
1230 	/* Find and lock the request corresponding to this xid */
1231 	spin_lock(&xprt->transport_lock);
1232 	req = xprt_lookup_rqst(xprt, transport->tcp_xid);
1233 	if (!req) {
1234 		dprintk("RPC:       XID %08x request not found!\n",
1235 				ntohl(transport->tcp_xid));
1236 		spin_unlock(&xprt->transport_lock);
1237 		return -1;
1238 	}
1239 
1240 	xs_tcp_read_common(xprt, desc, req);
1241 
1242 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
1243 		xprt_complete_rqst(req->rq_task, transport->tcp_copied);
1244 
1245 	spin_unlock(&xprt->transport_lock);
1246 	return 0;
1247 }
1248 
1249 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1250 /*
1251  * Obtains an rpc_rqst previously allocated and invokes the common
1252  * tcp read code to read the data.  The result is placed in the callback
1253  * queue.
1254  * If we're unable to obtain the rpc_rqst we schedule the closing of the
1255  * connection and return -1.
1256  */
1257 static inline int xs_tcp_read_callback(struct rpc_xprt *xprt,
1258 				       struct xdr_skb_reader *desc)
1259 {
1260 	struct sock_xprt *transport =
1261 				container_of(xprt, struct sock_xprt, xprt);
1262 	struct rpc_rqst *req;
1263 
1264 	req = xprt_alloc_bc_request(xprt);
1265 	if (req == NULL) {
1266 		printk(KERN_WARNING "Callback slot table overflowed\n");
1267 		xprt_force_disconnect(xprt);
1268 		return -1;
1269 	}
1270 
1271 	req->rq_xid = transport->tcp_xid;
1272 	dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
1273 	xs_tcp_read_common(xprt, desc, req);
1274 
1275 	if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) {
1276 		struct svc_serv *bc_serv = xprt->bc_serv;
1277 
1278 		/*
1279 		 * Add callback request to callback list.  The callback
1280 		 * service sleeps on the sv_cb_waitq waiting for new
1281 		 * requests.  Wake it up after adding enqueing the
1282 		 * request.
1283 		 */
1284 		dprintk("RPC:       add callback request to list\n");
1285 		spin_lock(&bc_serv->sv_cb_lock);
1286 		list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
1287 		spin_unlock(&bc_serv->sv_cb_lock);
1288 		wake_up(&bc_serv->sv_cb_waitq);
1289 	}
1290 
1291 	req->rq_private_buf.len = transport->tcp_copied;
1292 
1293 	return 0;
1294 }
1295 
1296 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1297 					struct xdr_skb_reader *desc)
1298 {
1299 	struct sock_xprt *transport =
1300 				container_of(xprt, struct sock_xprt, xprt);
1301 
1302 	return (transport->tcp_flags & TCP_RPC_REPLY) ?
1303 		xs_tcp_read_reply(xprt, desc) :
1304 		xs_tcp_read_callback(xprt, desc);
1305 }
1306 #else
1307 static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
1308 					struct xdr_skb_reader *desc)
1309 {
1310 	return xs_tcp_read_reply(xprt, desc);
1311 }
1312 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1313 
1314 /*
1315  * Read data off the transport.  This can be either an RPC_CALL or an
1316  * RPC_REPLY.  Relay the processing to helper functions.
1317  */
1318 static void xs_tcp_read_data(struct rpc_xprt *xprt,
1319 				    struct xdr_skb_reader *desc)
1320 {
1321 	struct sock_xprt *transport =
1322 				container_of(xprt, struct sock_xprt, xprt);
1323 
1324 	if (_xs_tcp_read_data(xprt, desc) == 0)
1325 		xs_tcp_check_fraghdr(transport);
1326 	else {
1327 		/*
1328 		 * The transport_lock protects the request handling.
1329 		 * There's no need to hold it to update the tcp_flags.
1330 		 */
1331 		transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
1332 	}
1333 }
1334 
1335 static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
1336 {
1337 	size_t len;
1338 
1339 	len = transport->tcp_reclen - transport->tcp_offset;
1340 	if (len > desc->count)
1341 		len = desc->count;
1342 	desc->count -= len;
1343 	desc->offset += len;
1344 	transport->tcp_offset += len;
1345 	dprintk("RPC:       discarded %Zu bytes\n", len);
1346 	xs_tcp_check_fraghdr(transport);
1347 }
1348 
1349 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
1350 {
1351 	struct rpc_xprt *xprt = rd_desc->arg.data;
1352 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1353 	struct xdr_skb_reader desc = {
1354 		.skb	= skb,
1355 		.offset	= offset,
1356 		.count	= len,
1357 	};
1358 
1359 	dprintk("RPC:       xs_tcp_data_recv started\n");
1360 	do {
1361 		/* Read in a new fragment marker if necessary */
1362 		/* Can we ever really expect to get completely empty fragments? */
1363 		if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
1364 			xs_tcp_read_fraghdr(xprt, &desc);
1365 			continue;
1366 		}
1367 		/* Read in the xid if necessary */
1368 		if (transport->tcp_flags & TCP_RCV_COPY_XID) {
1369 			xs_tcp_read_xid(transport, &desc);
1370 			continue;
1371 		}
1372 		/* Read in the call/reply flag */
1373 		if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
1374 			xs_tcp_read_calldir(transport, &desc);
1375 			continue;
1376 		}
1377 		/* Read in the request data */
1378 		if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
1379 			xs_tcp_read_data(xprt, &desc);
1380 			continue;
1381 		}
1382 		/* Skip over any trailing bytes on short reads */
1383 		xs_tcp_read_discard(transport, &desc);
1384 	} while (desc.count);
1385 	dprintk("RPC:       xs_tcp_data_recv done\n");
1386 	return len - desc.count;
1387 }
1388 
1389 /**
1390  * xs_tcp_data_ready - "data ready" callback for TCP sockets
1391  * @sk: socket with data to read
1392  * @bytes: how much data to read
1393  *
1394  */
1395 static void xs_tcp_data_ready(struct sock *sk, int bytes)
1396 {
1397 	struct rpc_xprt *xprt;
1398 	read_descriptor_t rd_desc;
1399 	int read;
1400 
1401 	dprintk("RPC:       xs_tcp_data_ready...\n");
1402 
1403 	read_lock_bh(&sk->sk_callback_lock);
1404 	if (!(xprt = xprt_from_sock(sk)))
1405 		goto out;
1406 	/* Any data means we had a useful conversation, so
1407 	 * the we don't need to delay the next reconnect
1408 	 */
1409 	if (xprt->reestablish_timeout)
1410 		xprt->reestablish_timeout = 0;
1411 
1412 	/* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
1413 	rd_desc.arg.data = xprt;
1414 	do {
1415 		rd_desc.count = 65536;
1416 		read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
1417 	} while (read > 0);
1418 out:
1419 	read_unlock_bh(&sk->sk_callback_lock);
1420 }
1421 
1422 /*
1423  * Do the equivalent of linger/linger2 handling for dealing with
1424  * broken servers that don't close the socket in a timely
1425  * fashion
1426  */
1427 static void xs_tcp_schedule_linger_timeout(struct rpc_xprt *xprt,
1428 		unsigned long timeout)
1429 {
1430 	struct sock_xprt *transport;
1431 
1432 	if (xprt_test_and_set_connecting(xprt))
1433 		return;
1434 	set_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1435 	transport = container_of(xprt, struct sock_xprt, xprt);
1436 	queue_delayed_work(rpciod_workqueue, &transport->connect_worker,
1437 			   timeout);
1438 }
1439 
1440 static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
1441 {
1442 	struct sock_xprt *transport;
1443 
1444 	transport = container_of(xprt, struct sock_xprt, xprt);
1445 
1446 	if (!test_bit(XPRT_CONNECTION_ABORT, &xprt->state) ||
1447 	    !cancel_delayed_work(&transport->connect_worker))
1448 		return;
1449 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1450 	xprt_clear_connecting(xprt);
1451 }
1452 
1453 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1454 {
1455 	smp_mb__before_clear_bit();
1456 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1457 	clear_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
1458 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1459 	clear_bit(XPRT_CLOSING, &xprt->state);
1460 	smp_mb__after_clear_bit();
1461 }
1462 
1463 static void xs_sock_mark_closed(struct rpc_xprt *xprt)
1464 {
1465 	xs_sock_reset_connection_flags(xprt);
1466 	/* Mark transport as closed and wake up all pending tasks */
1467 	xprt_disconnect_done(xprt);
1468 }
1469 
1470 /**
1471  * xs_tcp_state_change - callback to handle TCP socket state changes
1472  * @sk: socket whose state has changed
1473  *
1474  */
1475 static void xs_tcp_state_change(struct sock *sk)
1476 {
1477 	struct rpc_xprt *xprt;
1478 
1479 	read_lock_bh(&sk->sk_callback_lock);
1480 	if (!(xprt = xprt_from_sock(sk)))
1481 		goto out;
1482 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1483 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1484 			sk->sk_state, xprt_connected(xprt),
1485 			sock_flag(sk, SOCK_DEAD),
1486 			sock_flag(sk, SOCK_ZAPPED),
1487 			sk->sk_shutdown);
1488 
1489 	switch (sk->sk_state) {
1490 	case TCP_ESTABLISHED:
1491 		spin_lock(&xprt->transport_lock);
1492 		if (!xprt_test_and_set_connected(xprt)) {
1493 			struct sock_xprt *transport = container_of(xprt,
1494 					struct sock_xprt, xprt);
1495 
1496 			/* Reset TCP record info */
1497 			transport->tcp_offset = 0;
1498 			transport->tcp_reclen = 0;
1499 			transport->tcp_copied = 0;
1500 			transport->tcp_flags =
1501 				TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
1502 
1503 			xprt_wake_pending_tasks(xprt, -EAGAIN);
1504 		}
1505 		spin_unlock(&xprt->transport_lock);
1506 		break;
1507 	case TCP_FIN_WAIT1:
1508 		/* The client initiated a shutdown of the socket */
1509 		xprt->connect_cookie++;
1510 		xprt->reestablish_timeout = 0;
1511 		set_bit(XPRT_CLOSING, &xprt->state);
1512 		smp_mb__before_clear_bit();
1513 		clear_bit(XPRT_CONNECTED, &xprt->state);
1514 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1515 		smp_mb__after_clear_bit();
1516 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1517 		break;
1518 	case TCP_CLOSE_WAIT:
1519 		/* The server initiated a shutdown of the socket */
1520 		xprt->connect_cookie++;
1521 		clear_bit(XPRT_CONNECTED, &xprt->state);
1522 		xs_tcp_force_close(xprt);
1523 	case TCP_CLOSING:
1524 		/*
1525 		 * If the server closed down the connection, make sure that
1526 		 * we back off before reconnecting
1527 		 */
1528 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1529 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1530 		break;
1531 	case TCP_LAST_ACK:
1532 		set_bit(XPRT_CLOSING, &xprt->state);
1533 		xs_tcp_schedule_linger_timeout(xprt, xs_tcp_fin_timeout);
1534 		smp_mb__before_clear_bit();
1535 		clear_bit(XPRT_CONNECTED, &xprt->state);
1536 		smp_mb__after_clear_bit();
1537 		break;
1538 	case TCP_CLOSE:
1539 		xs_tcp_cancel_linger_timeout(xprt);
1540 		xs_sock_mark_closed(xprt);
1541 	}
1542  out:
1543 	read_unlock_bh(&sk->sk_callback_lock);
1544 }
1545 
1546 static void xs_write_space(struct sock *sk)
1547 {
1548 	struct socket *sock;
1549 	struct rpc_xprt *xprt;
1550 
1551 	if (unlikely(!(sock = sk->sk_socket)))
1552 		return;
1553 	clear_bit(SOCK_NOSPACE, &sock->flags);
1554 
1555 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1556 		return;
1557 	if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
1558 		return;
1559 
1560 	xprt_write_space(xprt);
1561 }
1562 
1563 /**
1564  * xs_udp_write_space - callback invoked when socket buffer space
1565  *                             becomes available
1566  * @sk: socket whose state has changed
1567  *
1568  * Called when more output buffer space is available for this socket.
1569  * We try not to wake our writers until they can make "significant"
1570  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1571  * with a bunch of small requests.
1572  */
1573 static void xs_udp_write_space(struct sock *sk)
1574 {
1575 	read_lock_bh(&sk->sk_callback_lock);
1576 
1577 	/* from net/core/sock.c:sock_def_write_space */
1578 	if (sock_writeable(sk))
1579 		xs_write_space(sk);
1580 
1581 	read_unlock_bh(&sk->sk_callback_lock);
1582 }
1583 
1584 /**
1585  * xs_tcp_write_space - callback invoked when socket buffer space
1586  *                             becomes available
1587  * @sk: socket whose state has changed
1588  *
1589  * Called when more output buffer space is available for this socket.
1590  * We try not to wake our writers until they can make "significant"
1591  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1592  * with a bunch of small requests.
1593  */
1594 static void xs_tcp_write_space(struct sock *sk)
1595 {
1596 	read_lock_bh(&sk->sk_callback_lock);
1597 
1598 	/* from net/core/stream.c:sk_stream_write_space */
1599 	if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk))
1600 		xs_write_space(sk);
1601 
1602 	read_unlock_bh(&sk->sk_callback_lock);
1603 }
1604 
1605 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1606 {
1607 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1608 	struct sock *sk = transport->inet;
1609 
1610 	if (transport->rcvsize) {
1611 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1612 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1613 	}
1614 	if (transport->sndsize) {
1615 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1616 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1617 		sk->sk_write_space(sk);
1618 	}
1619 }
1620 
1621 /**
1622  * xs_udp_set_buffer_size - set send and receive limits
1623  * @xprt: generic transport
1624  * @sndsize: requested size of send buffer, in bytes
1625  * @rcvsize: requested size of receive buffer, in bytes
1626  *
1627  * Set socket send and receive buffer size limits.
1628  */
1629 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1630 {
1631 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1632 
1633 	transport->sndsize = 0;
1634 	if (sndsize)
1635 		transport->sndsize = sndsize + 1024;
1636 	transport->rcvsize = 0;
1637 	if (rcvsize)
1638 		transport->rcvsize = rcvsize + 1024;
1639 
1640 	xs_udp_do_set_buffer_size(xprt);
1641 }
1642 
1643 /**
1644  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1645  * @task: task that timed out
1646  *
1647  * Adjust the congestion window after a retransmit timeout has occurred.
1648  */
1649 static void xs_udp_timer(struct rpc_task *task)
1650 {
1651 	xprt_adjust_cwnd(task, -ETIMEDOUT);
1652 }
1653 
1654 static unsigned short xs_get_random_port(void)
1655 {
1656 	unsigned short range = xprt_max_resvport - xprt_min_resvport;
1657 	unsigned short rand = (unsigned short) net_random() % range;
1658 	return rand + xprt_min_resvport;
1659 }
1660 
1661 /**
1662  * xs_set_port - reset the port number in the remote endpoint address
1663  * @xprt: generic transport
1664  * @port: new port number
1665  *
1666  */
1667 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1668 {
1669 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1670 
1671 	rpc_set_port(xs_addr(xprt), port);
1672 	xs_update_peer_port(xprt);
1673 }
1674 
1675 static unsigned short xs_get_srcport(struct sock_xprt *transport)
1676 {
1677 	unsigned short port = transport->srcport;
1678 
1679 	if (port == 0 && transport->xprt.resvport)
1680 		port = xs_get_random_port();
1681 	return port;
1682 }
1683 
1684 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1685 {
1686 	if (transport->srcport != 0)
1687 		transport->srcport = 0;
1688 	if (!transport->xprt.resvport)
1689 		return 0;
1690 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1691 		return xprt_max_resvport;
1692 	return --port;
1693 }
1694 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1695 {
1696 	struct sockaddr_storage myaddr;
1697 	int err, nloop = 0;
1698 	unsigned short port = xs_get_srcport(transport);
1699 	unsigned short last;
1700 
1701 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1702 	do {
1703 		rpc_set_port((struct sockaddr *)&myaddr, port);
1704 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1705 				transport->xprt.addrlen);
1706 		if (port == 0)
1707 			break;
1708 		if (err == 0) {
1709 			transport->srcport = port;
1710 			break;
1711 		}
1712 		last = port;
1713 		port = xs_next_srcport(transport, port);
1714 		if (port > last)
1715 			nloop++;
1716 	} while (err == -EADDRINUSE && nloop != 2);
1717 
1718 	if (myaddr.ss_family == AF_INET)
1719 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1720 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1721 				port, err ? "failed" : "ok", err);
1722 	else
1723 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1724 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1725 				port, err ? "failed" : "ok", err);
1726 	return err;
1727 }
1728 
1729 /*
1730  * We don't support autobind on AF_LOCAL sockets
1731  */
1732 static void xs_local_rpcbind(struct rpc_task *task)
1733 {
1734 	xprt_set_bound(task->tk_xprt);
1735 }
1736 
1737 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1738 {
1739 }
1740 
1741 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1742 static struct lock_class_key xs_key[2];
1743 static struct lock_class_key xs_slock_key[2];
1744 
1745 static inline void xs_reclassify_socketu(struct socket *sock)
1746 {
1747 	struct sock *sk = sock->sk;
1748 
1749 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1750 		&xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
1751 }
1752 
1753 static inline void xs_reclassify_socket4(struct socket *sock)
1754 {
1755 	struct sock *sk = sock->sk;
1756 
1757 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1758 		&xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
1759 }
1760 
1761 static inline void xs_reclassify_socket6(struct socket *sock)
1762 {
1763 	struct sock *sk = sock->sk;
1764 
1765 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1766 		&xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
1767 }
1768 
1769 static inline void xs_reclassify_socket(int family, struct socket *sock)
1770 {
1771 	WARN_ON_ONCE(sock_owned_by_user(sock->sk));
1772 	if (sock_owned_by_user(sock->sk))
1773 		return;
1774 
1775 	switch (family) {
1776 	case AF_LOCAL:
1777 		xs_reclassify_socketu(sock);
1778 		break;
1779 	case AF_INET:
1780 		xs_reclassify_socket4(sock);
1781 		break;
1782 	case AF_INET6:
1783 		xs_reclassify_socket6(sock);
1784 		break;
1785 	}
1786 }
1787 #else
1788 static inline void xs_reclassify_socketu(struct socket *sock)
1789 {
1790 }
1791 
1792 static inline void xs_reclassify_socket4(struct socket *sock)
1793 {
1794 }
1795 
1796 static inline void xs_reclassify_socket6(struct socket *sock)
1797 {
1798 }
1799 
1800 static inline void xs_reclassify_socket(int family, struct socket *sock)
1801 {
1802 }
1803 #endif
1804 
1805 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1806 		struct sock_xprt *transport, int family, int type, int protocol)
1807 {
1808 	struct socket *sock;
1809 	int err;
1810 
1811 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1812 	if (err < 0) {
1813 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1814 				protocol, -err);
1815 		goto out;
1816 	}
1817 	xs_reclassify_socket(family, sock);
1818 
1819 	err = xs_bind(transport, sock);
1820 	if (err) {
1821 		sock_release(sock);
1822 		goto out;
1823 	}
1824 
1825 	return sock;
1826 out:
1827 	return ERR_PTR(err);
1828 }
1829 
1830 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1831 				      struct socket *sock)
1832 {
1833 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1834 									xprt);
1835 
1836 	if (!transport->inet) {
1837 		struct sock *sk = sock->sk;
1838 
1839 		write_lock_bh(&sk->sk_callback_lock);
1840 
1841 		xs_save_old_callbacks(transport, sk);
1842 
1843 		sk->sk_user_data = xprt;
1844 		sk->sk_data_ready = xs_local_data_ready;
1845 		sk->sk_write_space = xs_udp_write_space;
1846 		sk->sk_allocation = GFP_ATOMIC;
1847 
1848 		xprt_clear_connected(xprt);
1849 
1850 		/* Reset to new socket */
1851 		transport->sock = sock;
1852 		transport->inet = sk;
1853 
1854 		write_unlock_bh(&sk->sk_callback_lock);
1855 	}
1856 
1857 	/* Tell the socket layer to start connecting... */
1858 	xprt->stat.connect_count++;
1859 	xprt->stat.connect_start = jiffies;
1860 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1861 }
1862 
1863 /**
1864  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1865  * @xprt: RPC transport to connect
1866  * @transport: socket transport to connect
1867  * @create_sock: function to create a socket of the correct type
1868  *
1869  * Invoked by a work queue tasklet.
1870  */
1871 static void xs_local_setup_socket(struct work_struct *work)
1872 {
1873 	struct sock_xprt *transport =
1874 		container_of(work, struct sock_xprt, connect_worker.work);
1875 	struct rpc_xprt *xprt = &transport->xprt;
1876 	struct socket *sock;
1877 	int status = -EIO;
1878 
1879 	current->flags |= PF_FSTRANS;
1880 
1881 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
1882 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1883 					SOCK_STREAM, 0, &sock, 1);
1884 	if (status < 0) {
1885 		dprintk("RPC:       can't create AF_LOCAL "
1886 			"transport socket (%d).\n", -status);
1887 		goto out;
1888 	}
1889 	xs_reclassify_socketu(sock);
1890 
1891 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1892 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1893 
1894 	status = xs_local_finish_connecting(xprt, sock);
1895 	switch (status) {
1896 	case 0:
1897 		dprintk("RPC:       xprt %p connected to %s\n",
1898 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1899 		xprt_set_connected(xprt);
1900 		break;
1901 	case -ENOENT:
1902 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1903 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1904 		break;
1905 	case -ECONNREFUSED:
1906 		dprintk("RPC:       xprt %p: connection refused for %s\n",
1907 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1908 		break;
1909 	default:
1910 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
1911 				__func__, -status,
1912 				xprt->address_strings[RPC_DISPLAY_ADDR]);
1913 	}
1914 
1915 out:
1916 	xprt_clear_connecting(xprt);
1917 	xprt_wake_pending_tasks(xprt, status);
1918 	current->flags &= ~PF_FSTRANS;
1919 }
1920 
1921 #ifdef CONFIG_SUNRPC_SWAP
1922 static void xs_set_memalloc(struct rpc_xprt *xprt)
1923 {
1924 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1925 			xprt);
1926 
1927 	if (xprt->swapper)
1928 		sk_set_memalloc(transport->inet);
1929 }
1930 
1931 /**
1932  * xs_swapper - Tag this transport as being used for swap.
1933  * @xprt: transport to tag
1934  * @enable: enable/disable
1935  *
1936  */
1937 int xs_swapper(struct rpc_xprt *xprt, int enable)
1938 {
1939 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1940 			xprt);
1941 	int err = 0;
1942 
1943 	if (enable) {
1944 		xprt->swapper++;
1945 		xs_set_memalloc(xprt);
1946 	} else if (xprt->swapper) {
1947 		xprt->swapper--;
1948 		sk_clear_memalloc(transport->inet);
1949 	}
1950 
1951 	return err;
1952 }
1953 EXPORT_SYMBOL_GPL(xs_swapper);
1954 #else
1955 static void xs_set_memalloc(struct rpc_xprt *xprt)
1956 {
1957 }
1958 #endif
1959 
1960 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
1961 {
1962 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1963 
1964 	if (!transport->inet) {
1965 		struct sock *sk = sock->sk;
1966 
1967 		write_lock_bh(&sk->sk_callback_lock);
1968 
1969 		xs_save_old_callbacks(transport, sk);
1970 
1971 		sk->sk_user_data = xprt;
1972 		sk->sk_data_ready = xs_udp_data_ready;
1973 		sk->sk_write_space = xs_udp_write_space;
1974 		sk->sk_no_check = UDP_CSUM_NORCV;
1975 		sk->sk_allocation = GFP_ATOMIC;
1976 
1977 		xprt_set_connected(xprt);
1978 
1979 		/* Reset to new socket */
1980 		transport->sock = sock;
1981 		transport->inet = sk;
1982 
1983 		xs_set_memalloc(xprt);
1984 
1985 		write_unlock_bh(&sk->sk_callback_lock);
1986 	}
1987 	xs_udp_do_set_buffer_size(xprt);
1988 }
1989 
1990 static void xs_udp_setup_socket(struct work_struct *work)
1991 {
1992 	struct sock_xprt *transport =
1993 		container_of(work, struct sock_xprt, connect_worker.work);
1994 	struct rpc_xprt *xprt = &transport->xprt;
1995 	struct socket *sock = transport->sock;
1996 	int status = -EIO;
1997 
1998 	current->flags |= PF_FSTRANS;
1999 
2000 	/* Start by resetting any existing state */
2001 	xs_reset_transport(transport);
2002 	sock = xs_create_sock(xprt, transport,
2003 			xs_addr(xprt)->sa_family, SOCK_DGRAM, IPPROTO_UDP);
2004 	if (IS_ERR(sock))
2005 		goto out;
2006 
2007 	dprintk("RPC:       worker connecting xprt %p via %s to "
2008 				"%s (port %s)\n", xprt,
2009 			xprt->address_strings[RPC_DISPLAY_PROTO],
2010 			xprt->address_strings[RPC_DISPLAY_ADDR],
2011 			xprt->address_strings[RPC_DISPLAY_PORT]);
2012 
2013 	xs_udp_finish_connecting(xprt, sock);
2014 	status = 0;
2015 out:
2016 	xprt_clear_connecting(xprt);
2017 	xprt_wake_pending_tasks(xprt, status);
2018 	current->flags &= ~PF_FSTRANS;
2019 }
2020 
2021 /*
2022  * We need to preserve the port number so the reply cache on the server can
2023  * find our cached RPC replies when we get around to reconnecting.
2024  */
2025 static void xs_abort_connection(struct sock_xprt *transport)
2026 {
2027 	int result;
2028 	struct sockaddr any;
2029 
2030 	dprintk("RPC:       disconnecting xprt %p to reuse port\n", transport);
2031 
2032 	/*
2033 	 * Disconnect the transport socket by doing a connect operation
2034 	 * with AF_UNSPEC.  This should return immediately...
2035 	 */
2036 	memset(&any, 0, sizeof(any));
2037 	any.sa_family = AF_UNSPEC;
2038 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
2039 	if (!result)
2040 		xs_sock_reset_connection_flags(&transport->xprt);
2041 	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
2042 }
2043 
2044 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
2045 {
2046 	unsigned int state = transport->inet->sk_state;
2047 
2048 	if (state == TCP_CLOSE && transport->sock->state == SS_UNCONNECTED) {
2049 		/* we don't need to abort the connection if the socket
2050 		 * hasn't undergone a shutdown
2051 		 */
2052 		if (transport->inet->sk_shutdown == 0)
2053 			return;
2054 		dprintk("RPC:       %s: TCP_CLOSEd and sk_shutdown set to %d\n",
2055 				__func__, transport->inet->sk_shutdown);
2056 	}
2057 	if ((1 << state) & (TCPF_ESTABLISHED|TCPF_SYN_SENT)) {
2058 		/* we don't need to abort the connection if the socket
2059 		 * hasn't undergone a shutdown
2060 		 */
2061 		if (transport->inet->sk_shutdown == 0)
2062 			return;
2063 		dprintk("RPC:       %s: ESTABLISHED/SYN_SENT "
2064 				"sk_shutdown set to %d\n",
2065 				__func__, transport->inet->sk_shutdown);
2066 	}
2067 	xs_abort_connection(transport);
2068 }
2069 
2070 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2071 {
2072 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2073 	int ret = -ENOTCONN;
2074 
2075 	if (!transport->inet) {
2076 		struct sock *sk = sock->sk;
2077 
2078 		write_lock_bh(&sk->sk_callback_lock);
2079 
2080 		xs_save_old_callbacks(transport, sk);
2081 
2082 		sk->sk_user_data = xprt;
2083 		sk->sk_data_ready = xs_tcp_data_ready;
2084 		sk->sk_state_change = xs_tcp_state_change;
2085 		sk->sk_write_space = xs_tcp_write_space;
2086 		sk->sk_allocation = GFP_ATOMIC;
2087 
2088 		/* socket options */
2089 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
2090 		sock_reset_flag(sk, SOCK_LINGER);
2091 		tcp_sk(sk)->linger2 = 0;
2092 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
2093 
2094 		xprt_clear_connected(xprt);
2095 
2096 		/* Reset to new socket */
2097 		transport->sock = sock;
2098 		transport->inet = sk;
2099 
2100 		write_unlock_bh(&sk->sk_callback_lock);
2101 	}
2102 
2103 	if (!xprt_bound(xprt))
2104 		goto out;
2105 
2106 	xs_set_memalloc(xprt);
2107 
2108 	/* Tell the socket layer to start connecting... */
2109 	xprt->stat.connect_count++;
2110 	xprt->stat.connect_start = jiffies;
2111 	ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2112 	switch (ret) {
2113 	case 0:
2114 	case -EINPROGRESS:
2115 		/* SYN_SENT! */
2116 		xprt->connect_cookie++;
2117 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2118 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2119 	}
2120 out:
2121 	return ret;
2122 }
2123 
2124 /**
2125  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2126  * @xprt: RPC transport to connect
2127  * @transport: socket transport to connect
2128  * @create_sock: function to create a socket of the correct type
2129  *
2130  * Invoked by a work queue tasklet.
2131  */
2132 static void xs_tcp_setup_socket(struct work_struct *work)
2133 {
2134 	struct sock_xprt *transport =
2135 		container_of(work, struct sock_xprt, connect_worker.work);
2136 	struct socket *sock = transport->sock;
2137 	struct rpc_xprt *xprt = &transport->xprt;
2138 	int status = -EIO;
2139 
2140 	current->flags |= PF_FSTRANS;
2141 
2142 	if (!sock) {
2143 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
2144 		sock = xs_create_sock(xprt, transport,
2145 				xs_addr(xprt)->sa_family, SOCK_STREAM, IPPROTO_TCP);
2146 		if (IS_ERR(sock)) {
2147 			status = PTR_ERR(sock);
2148 			goto out;
2149 		}
2150 	} else {
2151 		int abort_and_exit;
2152 
2153 		abort_and_exit = test_and_clear_bit(XPRT_CONNECTION_ABORT,
2154 				&xprt->state);
2155 		/* "close" the socket, preserving the local port */
2156 		xs_tcp_reuse_connection(transport);
2157 
2158 		if (abort_and_exit)
2159 			goto out_eagain;
2160 	}
2161 
2162 	dprintk("RPC:       worker connecting xprt %p via %s to "
2163 				"%s (port %s)\n", xprt,
2164 			xprt->address_strings[RPC_DISPLAY_PROTO],
2165 			xprt->address_strings[RPC_DISPLAY_ADDR],
2166 			xprt->address_strings[RPC_DISPLAY_PORT]);
2167 
2168 	status = xs_tcp_finish_connecting(xprt, sock);
2169 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2170 			xprt, -status, xprt_connected(xprt),
2171 			sock->sk->sk_state);
2172 	switch (status) {
2173 	default:
2174 		printk("%s: connect returned unhandled error %d\n",
2175 			__func__, status);
2176 	case -EADDRNOTAVAIL:
2177 		/* We're probably in TIME_WAIT. Get rid of existing socket,
2178 		 * and retry
2179 		 */
2180 		xs_tcp_force_close(xprt);
2181 		break;
2182 	case -ECONNREFUSED:
2183 	case -ECONNRESET:
2184 	case -ENETUNREACH:
2185 		/* retry with existing socket, after a delay */
2186 	case 0:
2187 	case -EINPROGRESS:
2188 	case -EALREADY:
2189 		xprt_clear_connecting(xprt);
2190 		current->flags &= ~PF_FSTRANS;
2191 		return;
2192 	case -EINVAL:
2193 		/* Happens, for instance, if the user specified a link
2194 		 * local IPv6 address without a scope-id.
2195 		 */
2196 		goto out;
2197 	}
2198 out_eagain:
2199 	status = -EAGAIN;
2200 out:
2201 	xprt_clear_connecting(xprt);
2202 	xprt_wake_pending_tasks(xprt, status);
2203 	current->flags &= ~PF_FSTRANS;
2204 }
2205 
2206 /**
2207  * xs_connect - connect a socket to a remote endpoint
2208  * @task: address of RPC task that manages state of connect request
2209  *
2210  * TCP: If the remote end dropped the connection, delay reconnecting.
2211  *
2212  * UDP socket connects are synchronous, but we use a work queue anyway
2213  * to guarantee that even unprivileged user processes can set up a
2214  * socket on a privileged port.
2215  *
2216  * If a UDP socket connect fails, the delay behavior here prevents
2217  * retry floods (hard mounts).
2218  */
2219 static void xs_connect(struct rpc_task *task)
2220 {
2221 	struct rpc_xprt *xprt = task->tk_xprt;
2222 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2223 
2224 	if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
2225 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2226 				"seconds\n",
2227 				xprt, xprt->reestablish_timeout / HZ);
2228 		queue_delayed_work(rpciod_workqueue,
2229 				   &transport->connect_worker,
2230 				   xprt->reestablish_timeout);
2231 		xprt->reestablish_timeout <<= 1;
2232 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2233 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2234 		if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
2235 			xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
2236 	} else {
2237 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2238 		queue_delayed_work(rpciod_workqueue,
2239 				   &transport->connect_worker, 0);
2240 	}
2241 }
2242 
2243 /**
2244  * xs_local_print_stats - display AF_LOCAL socket-specifc stats
2245  * @xprt: rpc_xprt struct containing statistics
2246  * @seq: output file
2247  *
2248  */
2249 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2250 {
2251 	long idle_time = 0;
2252 
2253 	if (xprt_connected(xprt))
2254 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2255 
2256 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2257 			"%llu %llu %lu %llu %llu\n",
2258 			xprt->stat.bind_count,
2259 			xprt->stat.connect_count,
2260 			xprt->stat.connect_time,
2261 			idle_time,
2262 			xprt->stat.sends,
2263 			xprt->stat.recvs,
2264 			xprt->stat.bad_xids,
2265 			xprt->stat.req_u,
2266 			xprt->stat.bklog_u,
2267 			xprt->stat.max_slots,
2268 			xprt->stat.sending_u,
2269 			xprt->stat.pending_u);
2270 }
2271 
2272 /**
2273  * xs_udp_print_stats - display UDP socket-specifc stats
2274  * @xprt: rpc_xprt struct containing statistics
2275  * @seq: output file
2276  *
2277  */
2278 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2279 {
2280 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2281 
2282 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2283 			"%lu %llu %llu\n",
2284 			transport->srcport,
2285 			xprt->stat.bind_count,
2286 			xprt->stat.sends,
2287 			xprt->stat.recvs,
2288 			xprt->stat.bad_xids,
2289 			xprt->stat.req_u,
2290 			xprt->stat.bklog_u,
2291 			xprt->stat.max_slots,
2292 			xprt->stat.sending_u,
2293 			xprt->stat.pending_u);
2294 }
2295 
2296 /**
2297  * xs_tcp_print_stats - display TCP socket-specifc stats
2298  * @xprt: rpc_xprt struct containing statistics
2299  * @seq: output file
2300  *
2301  */
2302 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2303 {
2304 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2305 	long idle_time = 0;
2306 
2307 	if (xprt_connected(xprt))
2308 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2309 
2310 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2311 			"%llu %llu %lu %llu %llu\n",
2312 			transport->srcport,
2313 			xprt->stat.bind_count,
2314 			xprt->stat.connect_count,
2315 			xprt->stat.connect_time,
2316 			idle_time,
2317 			xprt->stat.sends,
2318 			xprt->stat.recvs,
2319 			xprt->stat.bad_xids,
2320 			xprt->stat.req_u,
2321 			xprt->stat.bklog_u,
2322 			xprt->stat.max_slots,
2323 			xprt->stat.sending_u,
2324 			xprt->stat.pending_u);
2325 }
2326 
2327 /*
2328  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2329  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2330  * to use the server side send routines.
2331  */
2332 static void *bc_malloc(struct rpc_task *task, size_t size)
2333 {
2334 	struct page *page;
2335 	struct rpc_buffer *buf;
2336 
2337 	WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
2338 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
2339 		return NULL;
2340 
2341 	page = alloc_page(GFP_KERNEL);
2342 	if (!page)
2343 		return NULL;
2344 
2345 	buf = page_address(page);
2346 	buf->len = PAGE_SIZE;
2347 
2348 	return buf->data;
2349 }
2350 
2351 /*
2352  * Free the space allocated in the bc_alloc routine
2353  */
2354 static void bc_free(void *buffer)
2355 {
2356 	struct rpc_buffer *buf;
2357 
2358 	if (!buffer)
2359 		return;
2360 
2361 	buf = container_of(buffer, struct rpc_buffer, data);
2362 	free_page((unsigned long)buf);
2363 }
2364 
2365 /*
2366  * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
2367  * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
2368  */
2369 static int bc_sendto(struct rpc_rqst *req)
2370 {
2371 	int len;
2372 	struct xdr_buf *xbufp = &req->rq_snd_buf;
2373 	struct rpc_xprt *xprt = req->rq_xprt;
2374 	struct sock_xprt *transport =
2375 				container_of(xprt, struct sock_xprt, xprt);
2376 	struct socket *sock = transport->sock;
2377 	unsigned long headoff;
2378 	unsigned long tailoff;
2379 
2380 	xs_encode_stream_record_marker(xbufp);
2381 
2382 	tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
2383 	headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
2384 	len = svc_send_common(sock, xbufp,
2385 			      virt_to_page(xbufp->head[0].iov_base), headoff,
2386 			      xbufp->tail[0].iov_base, tailoff);
2387 
2388 	if (len != xbufp->len) {
2389 		printk(KERN_NOTICE "Error sending entire callback!\n");
2390 		len = -EAGAIN;
2391 	}
2392 
2393 	return len;
2394 }
2395 
2396 /*
2397  * The send routine. Borrows from svc_send
2398  */
2399 static int bc_send_request(struct rpc_task *task)
2400 {
2401 	struct rpc_rqst *req = task->tk_rqstp;
2402 	struct svc_xprt	*xprt;
2403 	u32                     len;
2404 
2405 	dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
2406 	/*
2407 	 * Get the server socket associated with this callback xprt
2408 	 */
2409 	xprt = req->rq_xprt->bc_xprt;
2410 
2411 	/*
2412 	 * Grab the mutex to serialize data as the connection is shared
2413 	 * with the fore channel
2414 	 */
2415 	if (!mutex_trylock(&xprt->xpt_mutex)) {
2416 		rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
2417 		if (!mutex_trylock(&xprt->xpt_mutex))
2418 			return -EAGAIN;
2419 		rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
2420 	}
2421 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2422 		len = -ENOTCONN;
2423 	else
2424 		len = bc_sendto(req);
2425 	mutex_unlock(&xprt->xpt_mutex);
2426 
2427 	if (len > 0)
2428 		len = 0;
2429 
2430 	return len;
2431 }
2432 
2433 /*
2434  * The close routine. Since this is client initiated, we do nothing
2435  */
2436 
2437 static void bc_close(struct rpc_xprt *xprt)
2438 {
2439 }
2440 
2441 /*
2442  * The xprt destroy routine. Again, because this connection is client
2443  * initiated, we do nothing
2444  */
2445 
2446 static void bc_destroy(struct rpc_xprt *xprt)
2447 {
2448 }
2449 
2450 static struct rpc_xprt_ops xs_local_ops = {
2451 	.reserve_xprt		= xprt_reserve_xprt,
2452 	.release_xprt		= xs_tcp_release_xprt,
2453 	.alloc_slot		= xprt_alloc_slot,
2454 	.rpcbind		= xs_local_rpcbind,
2455 	.set_port		= xs_local_set_port,
2456 	.connect		= xs_connect,
2457 	.buf_alloc		= rpc_malloc,
2458 	.buf_free		= rpc_free,
2459 	.send_request		= xs_local_send_request,
2460 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2461 	.close			= xs_close,
2462 	.destroy		= xs_destroy,
2463 	.print_stats		= xs_local_print_stats,
2464 };
2465 
2466 static struct rpc_xprt_ops xs_udp_ops = {
2467 	.set_buffer_size	= xs_udp_set_buffer_size,
2468 	.reserve_xprt		= xprt_reserve_xprt_cong,
2469 	.release_xprt		= xprt_release_xprt_cong,
2470 	.alloc_slot		= xprt_alloc_slot,
2471 	.rpcbind		= rpcb_getport_async,
2472 	.set_port		= xs_set_port,
2473 	.connect		= xs_connect,
2474 	.buf_alloc		= rpc_malloc,
2475 	.buf_free		= rpc_free,
2476 	.send_request		= xs_udp_send_request,
2477 	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,
2478 	.timer			= xs_udp_timer,
2479 	.release_request	= xprt_release_rqst_cong,
2480 	.close			= xs_close,
2481 	.destroy		= xs_destroy,
2482 	.print_stats		= xs_udp_print_stats,
2483 };
2484 
2485 static struct rpc_xprt_ops xs_tcp_ops = {
2486 	.reserve_xprt		= xprt_reserve_xprt,
2487 	.release_xprt		= xs_tcp_release_xprt,
2488 	.alloc_slot		= xprt_lock_and_alloc_slot,
2489 	.rpcbind		= rpcb_getport_async,
2490 	.set_port		= xs_set_port,
2491 	.connect		= xs_connect,
2492 	.buf_alloc		= rpc_malloc,
2493 	.buf_free		= rpc_free,
2494 	.send_request		= xs_tcp_send_request,
2495 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2496 	.close			= xs_tcp_close,
2497 	.destroy		= xs_destroy,
2498 	.print_stats		= xs_tcp_print_stats,
2499 };
2500 
2501 /*
2502  * The rpc_xprt_ops for the server backchannel
2503  */
2504 
2505 static struct rpc_xprt_ops bc_tcp_ops = {
2506 	.reserve_xprt		= xprt_reserve_xprt,
2507 	.release_xprt		= xprt_release_xprt,
2508 	.alloc_slot		= xprt_alloc_slot,
2509 	.rpcbind		= xs_local_rpcbind,
2510 	.buf_alloc		= bc_malloc,
2511 	.buf_free		= bc_free,
2512 	.send_request		= bc_send_request,
2513 	.set_retrans_timeout	= xprt_set_retrans_timeout_def,
2514 	.close			= bc_close,
2515 	.destroy		= bc_destroy,
2516 	.print_stats		= xs_tcp_print_stats,
2517 };
2518 
2519 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2520 {
2521 	static const struct sockaddr_in sin = {
2522 		.sin_family		= AF_INET,
2523 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2524 	};
2525 	static const struct sockaddr_in6 sin6 = {
2526 		.sin6_family		= AF_INET6,
2527 		.sin6_addr		= IN6ADDR_ANY_INIT,
2528 	};
2529 
2530 	switch (family) {
2531 	case AF_LOCAL:
2532 		break;
2533 	case AF_INET:
2534 		memcpy(sap, &sin, sizeof(sin));
2535 		break;
2536 	case AF_INET6:
2537 		memcpy(sap, &sin6, sizeof(sin6));
2538 		break;
2539 	default:
2540 		dprintk("RPC:       %s: Bad address family\n", __func__);
2541 		return -EAFNOSUPPORT;
2542 	}
2543 	return 0;
2544 }
2545 
2546 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2547 				      unsigned int slot_table_size,
2548 				      unsigned int max_slot_table_size)
2549 {
2550 	struct rpc_xprt *xprt;
2551 	struct sock_xprt *new;
2552 
2553 	if (args->addrlen > sizeof(xprt->addr)) {
2554 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2555 		return ERR_PTR(-EBADF);
2556 	}
2557 
2558 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2559 			max_slot_table_size);
2560 	if (xprt == NULL) {
2561 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2562 				"rpc_xprt\n");
2563 		return ERR_PTR(-ENOMEM);
2564 	}
2565 
2566 	new = container_of(xprt, struct sock_xprt, xprt);
2567 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2568 	xprt->addrlen = args->addrlen;
2569 	if (args->srcaddr)
2570 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2571 	else {
2572 		int err;
2573 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2574 					(struct sockaddr *)&new->srcaddr);
2575 		if (err != 0) {
2576 			xprt_free(xprt);
2577 			return ERR_PTR(err);
2578 		}
2579 	}
2580 
2581 	return xprt;
2582 }
2583 
2584 static const struct rpc_timeout xs_local_default_timeout = {
2585 	.to_initval = 10 * HZ,
2586 	.to_maxval = 10 * HZ,
2587 	.to_retries = 2,
2588 };
2589 
2590 /**
2591  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2592  * @args: rpc transport creation arguments
2593  *
2594  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2595  */
2596 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2597 {
2598 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2599 	struct sock_xprt *transport;
2600 	struct rpc_xprt *xprt;
2601 	struct rpc_xprt *ret;
2602 
2603 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2604 			xprt_max_tcp_slot_table_entries);
2605 	if (IS_ERR(xprt))
2606 		return xprt;
2607 	transport = container_of(xprt, struct sock_xprt, xprt);
2608 
2609 	xprt->prot = 0;
2610 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2611 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2612 
2613 	xprt->bind_timeout = XS_BIND_TO;
2614 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2615 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2616 
2617 	xprt->ops = &xs_local_ops;
2618 	xprt->timeout = &xs_local_default_timeout;
2619 
2620 	switch (sun->sun_family) {
2621 	case AF_LOCAL:
2622 		if (sun->sun_path[0] != '/') {
2623 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2624 					sun->sun_path);
2625 			ret = ERR_PTR(-EINVAL);
2626 			goto out_err;
2627 		}
2628 		xprt_set_bound(xprt);
2629 		INIT_DELAYED_WORK(&transport->connect_worker,
2630 					xs_local_setup_socket);
2631 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2632 		break;
2633 	default:
2634 		ret = ERR_PTR(-EAFNOSUPPORT);
2635 		goto out_err;
2636 	}
2637 
2638 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2639 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2640 
2641 	if (try_module_get(THIS_MODULE))
2642 		return xprt;
2643 	ret = ERR_PTR(-EINVAL);
2644 out_err:
2645 	xprt_free(xprt);
2646 	return ret;
2647 }
2648 
2649 static const struct rpc_timeout xs_udp_default_timeout = {
2650 	.to_initval = 5 * HZ,
2651 	.to_maxval = 30 * HZ,
2652 	.to_increment = 5 * HZ,
2653 	.to_retries = 5,
2654 };
2655 
2656 /**
2657  * xs_setup_udp - Set up transport to use a UDP socket
2658  * @args: rpc transport creation arguments
2659  *
2660  */
2661 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2662 {
2663 	struct sockaddr *addr = args->dstaddr;
2664 	struct rpc_xprt *xprt;
2665 	struct sock_xprt *transport;
2666 	struct rpc_xprt *ret;
2667 
2668 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2669 			xprt_udp_slot_table_entries);
2670 	if (IS_ERR(xprt))
2671 		return xprt;
2672 	transport = container_of(xprt, struct sock_xprt, xprt);
2673 
2674 	xprt->prot = IPPROTO_UDP;
2675 	xprt->tsh_size = 0;
2676 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2677 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2678 
2679 	xprt->bind_timeout = XS_BIND_TO;
2680 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2681 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2682 
2683 	xprt->ops = &xs_udp_ops;
2684 
2685 	xprt->timeout = &xs_udp_default_timeout;
2686 
2687 	switch (addr->sa_family) {
2688 	case AF_INET:
2689 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2690 			xprt_set_bound(xprt);
2691 
2692 		INIT_DELAYED_WORK(&transport->connect_worker,
2693 					xs_udp_setup_socket);
2694 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2695 		break;
2696 	case AF_INET6:
2697 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2698 			xprt_set_bound(xprt);
2699 
2700 		INIT_DELAYED_WORK(&transport->connect_worker,
2701 					xs_udp_setup_socket);
2702 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2703 		break;
2704 	default:
2705 		ret = ERR_PTR(-EAFNOSUPPORT);
2706 		goto out_err;
2707 	}
2708 
2709 	if (xprt_bound(xprt))
2710 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2711 				xprt->address_strings[RPC_DISPLAY_ADDR],
2712 				xprt->address_strings[RPC_DISPLAY_PORT],
2713 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2714 	else
2715 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2716 				xprt->address_strings[RPC_DISPLAY_ADDR],
2717 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2718 
2719 	if (try_module_get(THIS_MODULE))
2720 		return xprt;
2721 	ret = ERR_PTR(-EINVAL);
2722 out_err:
2723 	xprt_free(xprt);
2724 	return ret;
2725 }
2726 
2727 static const struct rpc_timeout xs_tcp_default_timeout = {
2728 	.to_initval = 60 * HZ,
2729 	.to_maxval = 60 * HZ,
2730 	.to_retries = 2,
2731 };
2732 
2733 /**
2734  * xs_setup_tcp - Set up transport to use a TCP socket
2735  * @args: rpc transport creation arguments
2736  *
2737  */
2738 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
2739 {
2740 	struct sockaddr *addr = args->dstaddr;
2741 	struct rpc_xprt *xprt;
2742 	struct sock_xprt *transport;
2743 	struct rpc_xprt *ret;
2744 
2745 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2746 			xprt_max_tcp_slot_table_entries);
2747 	if (IS_ERR(xprt))
2748 		return xprt;
2749 	transport = container_of(xprt, struct sock_xprt, xprt);
2750 
2751 	xprt->prot = IPPROTO_TCP;
2752 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2753 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2754 
2755 	xprt->bind_timeout = XS_BIND_TO;
2756 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2757 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2758 
2759 	xprt->ops = &xs_tcp_ops;
2760 	xprt->timeout = &xs_tcp_default_timeout;
2761 
2762 	switch (addr->sa_family) {
2763 	case AF_INET:
2764 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2765 			xprt_set_bound(xprt);
2766 
2767 		INIT_DELAYED_WORK(&transport->connect_worker,
2768 					xs_tcp_setup_socket);
2769 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
2770 		break;
2771 	case AF_INET6:
2772 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2773 			xprt_set_bound(xprt);
2774 
2775 		INIT_DELAYED_WORK(&transport->connect_worker,
2776 					xs_tcp_setup_socket);
2777 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
2778 		break;
2779 	default:
2780 		ret = ERR_PTR(-EAFNOSUPPORT);
2781 		goto out_err;
2782 	}
2783 
2784 	if (xprt_bound(xprt))
2785 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2786 				xprt->address_strings[RPC_DISPLAY_ADDR],
2787 				xprt->address_strings[RPC_DISPLAY_PORT],
2788 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2789 	else
2790 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
2791 				xprt->address_strings[RPC_DISPLAY_ADDR],
2792 				xprt->address_strings[RPC_DISPLAY_PROTO]);
2793 
2794 
2795 	if (try_module_get(THIS_MODULE))
2796 		return xprt;
2797 	ret = ERR_PTR(-EINVAL);
2798 out_err:
2799 	xprt_free(xprt);
2800 	return ret;
2801 }
2802 
2803 /**
2804  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
2805  * @args: rpc transport creation arguments
2806  *
2807  */
2808 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
2809 {
2810 	struct sockaddr *addr = args->dstaddr;
2811 	struct rpc_xprt *xprt;
2812 	struct sock_xprt *transport;
2813 	struct svc_sock *bc_sock;
2814 	struct rpc_xprt *ret;
2815 
2816 	if (args->bc_xprt->xpt_bc_xprt) {
2817 		/*
2818 		 * This server connection already has a backchannel
2819 		 * export; we can't create a new one, as we wouldn't be
2820 		 * able to match replies based on xid any more.  So,
2821 		 * reuse the already-existing one:
2822 		 */
2823 		 return args->bc_xprt->xpt_bc_xprt;
2824 	}
2825 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2826 			xprt_tcp_slot_table_entries);
2827 	if (IS_ERR(xprt))
2828 		return xprt;
2829 	transport = container_of(xprt, struct sock_xprt, xprt);
2830 
2831 	xprt->prot = IPPROTO_TCP;
2832 	xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
2833 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2834 	xprt->timeout = &xs_tcp_default_timeout;
2835 
2836 	/* backchannel */
2837 	xprt_set_bound(xprt);
2838 	xprt->bind_timeout = 0;
2839 	xprt->reestablish_timeout = 0;
2840 	xprt->idle_timeout = 0;
2841 
2842 	xprt->ops = &bc_tcp_ops;
2843 
2844 	switch (addr->sa_family) {
2845 	case AF_INET:
2846 		xs_format_peer_addresses(xprt, "tcp",
2847 					 RPCBIND_NETID_TCP);
2848 		break;
2849 	case AF_INET6:
2850 		xs_format_peer_addresses(xprt, "tcp",
2851 				   RPCBIND_NETID_TCP6);
2852 		break;
2853 	default:
2854 		ret = ERR_PTR(-EAFNOSUPPORT);
2855 		goto out_err;
2856 	}
2857 
2858 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
2859 			xprt->address_strings[RPC_DISPLAY_ADDR],
2860 			xprt->address_strings[RPC_DISPLAY_PORT],
2861 			xprt->address_strings[RPC_DISPLAY_PROTO]);
2862 
2863 	/*
2864 	 * Once we've associated a backchannel xprt with a connection,
2865 	 * we want to keep it around as long as long as the connection
2866 	 * lasts, in case we need to start using it for a backchannel
2867 	 * again; this reference won't be dropped until bc_xprt is
2868 	 * destroyed.
2869 	 */
2870 	xprt_get(xprt);
2871 	args->bc_xprt->xpt_bc_xprt = xprt;
2872 	xprt->bc_xprt = args->bc_xprt;
2873 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
2874 	transport->sock = bc_sock->sk_sock;
2875 	transport->inet = bc_sock->sk_sk;
2876 
2877 	/*
2878 	 * Since we don't want connections for the backchannel, we set
2879 	 * the xprt status to connected
2880 	 */
2881 	xprt_set_connected(xprt);
2882 
2883 
2884 	if (try_module_get(THIS_MODULE))
2885 		return xprt;
2886 	xprt_put(xprt);
2887 	ret = ERR_PTR(-EINVAL);
2888 out_err:
2889 	xprt_free(xprt);
2890 	return ret;
2891 }
2892 
2893 static struct xprt_class	xs_local_transport = {
2894 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
2895 	.name		= "named UNIX socket",
2896 	.owner		= THIS_MODULE,
2897 	.ident		= XPRT_TRANSPORT_LOCAL,
2898 	.setup		= xs_setup_local,
2899 };
2900 
2901 static struct xprt_class	xs_udp_transport = {
2902 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
2903 	.name		= "udp",
2904 	.owner		= THIS_MODULE,
2905 	.ident		= XPRT_TRANSPORT_UDP,
2906 	.setup		= xs_setup_udp,
2907 };
2908 
2909 static struct xprt_class	xs_tcp_transport = {
2910 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
2911 	.name		= "tcp",
2912 	.owner		= THIS_MODULE,
2913 	.ident		= XPRT_TRANSPORT_TCP,
2914 	.setup		= xs_setup_tcp,
2915 };
2916 
2917 static struct xprt_class	xs_bc_tcp_transport = {
2918 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
2919 	.name		= "tcp NFSv4.1 backchannel",
2920 	.owner		= THIS_MODULE,
2921 	.ident		= XPRT_TRANSPORT_BC_TCP,
2922 	.setup		= xs_setup_bc_tcp,
2923 };
2924 
2925 /**
2926  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
2927  *
2928  */
2929 int init_socket_xprt(void)
2930 {
2931 #ifdef RPC_DEBUG
2932 	if (!sunrpc_table_header)
2933 		sunrpc_table_header = register_sysctl_table(sunrpc_table);
2934 #endif
2935 
2936 	xprt_register_transport(&xs_local_transport);
2937 	xprt_register_transport(&xs_udp_transport);
2938 	xprt_register_transport(&xs_tcp_transport);
2939 	xprt_register_transport(&xs_bc_tcp_transport);
2940 
2941 	return 0;
2942 }
2943 
2944 /**
2945  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
2946  *
2947  */
2948 void cleanup_socket_xprt(void)
2949 {
2950 #ifdef RPC_DEBUG
2951 	if (sunrpc_table_header) {
2952 		unregister_sysctl_table(sunrpc_table_header);
2953 		sunrpc_table_header = NULL;
2954 	}
2955 #endif
2956 
2957 	xprt_unregister_transport(&xs_local_transport);
2958 	xprt_unregister_transport(&xs_udp_transport);
2959 	xprt_unregister_transport(&xs_tcp_transport);
2960 	xprt_unregister_transport(&xs_bc_tcp_transport);
2961 }
2962 
2963 static int param_set_uint_minmax(const char *val,
2964 		const struct kernel_param *kp,
2965 		unsigned int min, unsigned int max)
2966 {
2967 	unsigned long num;
2968 	int ret;
2969 
2970 	if (!val)
2971 		return -EINVAL;
2972 	ret = strict_strtoul(val, 0, &num);
2973 	if (ret == -EINVAL || num < min || num > max)
2974 		return -EINVAL;
2975 	*((unsigned int *)kp->arg) = num;
2976 	return 0;
2977 }
2978 
2979 static int param_set_portnr(const char *val, const struct kernel_param *kp)
2980 {
2981 	return param_set_uint_minmax(val, kp,
2982 			RPC_MIN_RESVPORT,
2983 			RPC_MAX_RESVPORT);
2984 }
2985 
2986 static struct kernel_param_ops param_ops_portnr = {
2987 	.set = param_set_portnr,
2988 	.get = param_get_uint,
2989 };
2990 
2991 #define param_check_portnr(name, p) \
2992 	__param_check(name, p, unsigned int);
2993 
2994 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
2995 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
2996 
2997 static int param_set_slot_table_size(const char *val,
2998 				     const struct kernel_param *kp)
2999 {
3000 	return param_set_uint_minmax(val, kp,
3001 			RPC_MIN_SLOT_TABLE,
3002 			RPC_MAX_SLOT_TABLE);
3003 }
3004 
3005 static struct kernel_param_ops param_ops_slot_table_size = {
3006 	.set = param_set_slot_table_size,
3007 	.get = param_get_uint,
3008 };
3009 
3010 #define param_check_slot_table_size(name, p) \
3011 	__param_check(name, p, unsigned int);
3012 
3013 static int param_set_max_slot_table_size(const char *val,
3014 				     const struct kernel_param *kp)
3015 {
3016 	return param_set_uint_minmax(val, kp,
3017 			RPC_MIN_SLOT_TABLE,
3018 			RPC_MAX_SLOT_TABLE_LIMIT);
3019 }
3020 
3021 static struct kernel_param_ops param_ops_max_slot_table_size = {
3022 	.set = param_set_max_slot_table_size,
3023 	.get = param_get_uint,
3024 };
3025 
3026 #define param_check_max_slot_table_size(name, p) \
3027 	__param_check(name, p, unsigned int);
3028 
3029 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3030 		   slot_table_size, 0644);
3031 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3032 		   max_slot_table_size, 0644);
3033 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3034 		   slot_table_size, 0644);
3035 
3036