xref: /openbmc/linux/net/sunrpc/xprtsock.c (revision dea034b963c8901bdcc3d3880c04f0d75c95112f)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/net/sunrpc/xprtsock.c
4  *
5  * Client-side transport implementation for sockets.
6  *
7  * TCP callback races fixes (C) 1998 Red Hat
8  * TCP send fixes (C) 1998 Red Hat
9  * TCP NFS related read + write fixes
10  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
11  *
12  * Rewrite of larges part of the code in order to stabilize TCP stuff.
13  * Fix behaviour when socket buffer is full.
14  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
15  *
16  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
17  *
18  * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
19  *   <gilles.quillard@bull.net>
20  */
21 
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/capability.h>
27 #include <linux/pagemap.h>
28 #include <linux/errno.h>
29 #include <linux/socket.h>
30 #include <linux/in.h>
31 #include <linux/net.h>
32 #include <linux/mm.h>
33 #include <linux/un.h>
34 #include <linux/udp.h>
35 #include <linux/tcp.h>
36 #include <linux/sunrpc/clnt.h>
37 #include <linux/sunrpc/addr.h>
38 #include <linux/sunrpc/sched.h>
39 #include <linux/sunrpc/svcsock.h>
40 #include <linux/sunrpc/xprtsock.h>
41 #include <linux/file.h>
42 #ifdef CONFIG_SUNRPC_BACKCHANNEL
43 #include <linux/sunrpc/bc_xprt.h>
44 #endif
45 
46 #include <net/sock.h>
47 #include <net/checksum.h>
48 #include <net/udp.h>
49 #include <net/tcp.h>
50 #include <net/tls.h>
51 
52 #include <linux/bvec.h>
53 #include <linux/highmem.h>
54 #include <linux/uio.h>
55 #include <linux/sched/mm.h>
56 
57 #include <trace/events/sock.h>
58 #include <trace/events/sunrpc.h>
59 
60 #include "socklib.h"
61 #include "sunrpc.h"
62 
63 static void xs_close(struct rpc_xprt *xprt);
64 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock);
65 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
66 		struct socket *sock);
67 
68 /*
69  * xprtsock tunables
70  */
71 static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
72 static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
73 static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
74 
75 static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
76 static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
77 
78 #define XS_TCP_LINGER_TO	(15U * HZ)
79 static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
80 
81 /*
82  * We can register our own files under /proc/sys/sunrpc by
83  * calling register_sysctl() again.  The files in that
84  * directory become the union of all files registered there.
85  *
86  * We simply need to make sure that we don't collide with
87  * someone else's file names!
88  */
89 
90 static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
91 static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
92 static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
93 static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
94 static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
95 
96 static struct ctl_table_header *sunrpc_table_header;
97 
98 static struct xprt_class xs_local_transport;
99 static struct xprt_class xs_udp_transport;
100 static struct xprt_class xs_tcp_transport;
101 static struct xprt_class xs_bc_tcp_transport;
102 
103 /*
104  * FIXME: changing the UDP slot table size should also resize the UDP
105  *        socket buffers for existing UDP transports
106  */
107 static struct ctl_table xs_tunables_table[] = {
108 	{
109 		.procname	= "udp_slot_table_entries",
110 		.data		= &xprt_udp_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_slot_table_size
116 	},
117 	{
118 		.procname	= "tcp_slot_table_entries",
119 		.data		= &xprt_tcp_slot_table_entries,
120 		.maxlen		= sizeof(unsigned int),
121 		.mode		= 0644,
122 		.proc_handler	= proc_dointvec_minmax,
123 		.extra1		= &min_slot_table_size,
124 		.extra2		= &max_slot_table_size
125 	},
126 	{
127 		.procname	= "tcp_max_slot_table_entries",
128 		.data		= &xprt_max_tcp_slot_table_entries,
129 		.maxlen		= sizeof(unsigned int),
130 		.mode		= 0644,
131 		.proc_handler	= proc_dointvec_minmax,
132 		.extra1		= &min_slot_table_size,
133 		.extra2		= &max_tcp_slot_table_limit
134 	},
135 	{
136 		.procname	= "min_resvport",
137 		.data		= &xprt_min_resvport,
138 		.maxlen		= sizeof(unsigned int),
139 		.mode		= 0644,
140 		.proc_handler	= proc_dointvec_minmax,
141 		.extra1		= &xprt_min_resvport_limit,
142 		.extra2		= &xprt_max_resvport_limit
143 	},
144 	{
145 		.procname	= "max_resvport",
146 		.data		= &xprt_max_resvport,
147 		.maxlen		= sizeof(unsigned int),
148 		.mode		= 0644,
149 		.proc_handler	= proc_dointvec_minmax,
150 		.extra1		= &xprt_min_resvport_limit,
151 		.extra2		= &xprt_max_resvport_limit
152 	},
153 	{
154 		.procname	= "tcp_fin_timeout",
155 		.data		= &xs_tcp_fin_timeout,
156 		.maxlen		= sizeof(xs_tcp_fin_timeout),
157 		.mode		= 0644,
158 		.proc_handler	= proc_dointvec_jiffies,
159 	},
160 	{ },
161 };
162 
163 /*
164  * Wait duration for a reply from the RPC portmapper.
165  */
166 #define XS_BIND_TO		(60U * HZ)
167 
168 /*
169  * Delay if a UDP socket connect error occurs.  This is most likely some
170  * kind of resource problem on the local host.
171  */
172 #define XS_UDP_REEST_TO		(2U * HZ)
173 
174 /*
175  * The reestablish timeout allows clients to delay for a bit before attempting
176  * to reconnect to a server that just dropped our connection.
177  *
178  * We implement an exponential backoff when trying to reestablish a TCP
179  * transport connection with the server.  Some servers like to drop a TCP
180  * connection when they are overworked, so we start with a short timeout and
181  * increase over time if the server is down or not responding.
182  */
183 #define XS_TCP_INIT_REEST_TO	(3U * HZ)
184 
185 /*
186  * TCP idle timeout; client drops the transport socket if it is idle
187  * for this long.  Note that we also timeout UDP sockets to prevent
188  * holding port numbers when there is no RPC traffic.
189  */
190 #define XS_IDLE_DISC_TO		(5U * 60 * HZ)
191 
192 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
193 # undef  RPC_DEBUG_DATA
194 # define RPCDBG_FACILITY	RPCDBG_TRANS
195 #endif
196 
197 #ifdef RPC_DEBUG_DATA
198 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
199 {
200 	u8 *buf = (u8 *) packet;
201 	int j;
202 
203 	dprintk("RPC:       %s\n", msg);
204 	for (j = 0; j < count && j < 128; j += 4) {
205 		if (!(j & 31)) {
206 			if (j)
207 				dprintk("\n");
208 			dprintk("0x%04x ", j);
209 		}
210 		dprintk("%02x%02x%02x%02x ",
211 			buf[j], buf[j+1], buf[j+2], buf[j+3]);
212 	}
213 	dprintk("\n");
214 }
215 #else
216 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
217 {
218 	/* NOP */
219 }
220 #endif
221 
222 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
223 {
224 	return (struct rpc_xprt *) sk->sk_user_data;
225 }
226 
227 static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
228 {
229 	return (struct sockaddr *) &xprt->addr;
230 }
231 
232 static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
233 {
234 	return (struct sockaddr_un *) &xprt->addr;
235 }
236 
237 static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
238 {
239 	return (struct sockaddr_in *) &xprt->addr;
240 }
241 
242 static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
243 {
244 	return (struct sockaddr_in6 *) &xprt->addr;
245 }
246 
247 static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
248 {
249 	struct sockaddr *sap = xs_addr(xprt);
250 	struct sockaddr_in6 *sin6;
251 	struct sockaddr_in *sin;
252 	struct sockaddr_un *sun;
253 	char buf[128];
254 
255 	switch (sap->sa_family) {
256 	case AF_LOCAL:
257 		sun = xs_addr_un(xprt);
258 		if (sun->sun_path[0]) {
259 			strscpy(buf, sun->sun_path, sizeof(buf));
260 		} else {
261 			buf[0] = '@';
262 			strscpy(buf+1, sun->sun_path+1, sizeof(buf)-1);
263 		}
264 		xprt->address_strings[RPC_DISPLAY_ADDR] =
265 						kstrdup(buf, GFP_KERNEL);
266 		break;
267 	case AF_INET:
268 		(void)rpc_ntop(sap, buf, sizeof(buf));
269 		xprt->address_strings[RPC_DISPLAY_ADDR] =
270 						kstrdup(buf, GFP_KERNEL);
271 		sin = xs_addr_in(xprt);
272 		snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
273 		break;
274 	case AF_INET6:
275 		(void)rpc_ntop(sap, buf, sizeof(buf));
276 		xprt->address_strings[RPC_DISPLAY_ADDR] =
277 						kstrdup(buf, GFP_KERNEL);
278 		sin6 = xs_addr_in6(xprt);
279 		snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
280 		break;
281 	default:
282 		BUG();
283 	}
284 
285 	xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
286 }
287 
288 static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
289 {
290 	struct sockaddr *sap = xs_addr(xprt);
291 	char buf[128];
292 
293 	snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
294 	xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
295 
296 	snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
297 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
298 }
299 
300 static void xs_format_peer_addresses(struct rpc_xprt *xprt,
301 				     const char *protocol,
302 				     const char *netid)
303 {
304 	xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
305 	xprt->address_strings[RPC_DISPLAY_NETID] = netid;
306 	xs_format_common_peer_addresses(xprt);
307 	xs_format_common_peer_ports(xprt);
308 }
309 
310 static void xs_update_peer_port(struct rpc_xprt *xprt)
311 {
312 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
313 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
314 
315 	xs_format_common_peer_ports(xprt);
316 }
317 
318 static void xs_free_peer_addresses(struct rpc_xprt *xprt)
319 {
320 	unsigned int i;
321 
322 	for (i = 0; i < RPC_DISPLAY_MAX; i++)
323 		switch (i) {
324 		case RPC_DISPLAY_PROTO:
325 		case RPC_DISPLAY_NETID:
326 			continue;
327 		default:
328 			kfree(xprt->address_strings[i]);
329 		}
330 }
331 
332 static size_t
333 xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
334 {
335 	size_t i,n;
336 
337 	if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES))
338 		return want;
339 	n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT;
340 	for (i = 0; i < n; i++) {
341 		if (buf->pages[i])
342 			continue;
343 		buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp);
344 		if (!buf->pages[i]) {
345 			i *= PAGE_SIZE;
346 			return i > buf->page_base ? i - buf->page_base : 0;
347 		}
348 	}
349 	return want;
350 }
351 
352 static int
353 xs_sock_process_cmsg(struct socket *sock, struct msghdr *msg,
354 		     struct cmsghdr *cmsg, int ret)
355 {
356 	if (cmsg->cmsg_level == SOL_TLS &&
357 	    cmsg->cmsg_type == TLS_GET_RECORD_TYPE) {
358 		u8 content_type = *((u8 *)CMSG_DATA(cmsg));
359 
360 		switch (content_type) {
361 		case TLS_RECORD_TYPE_DATA:
362 			/* TLS sets EOR at the end of each application data
363 			 * record, even though there might be more frames
364 			 * waiting to be decrypted.
365 			 */
366 			msg->msg_flags &= ~MSG_EOR;
367 			break;
368 		case TLS_RECORD_TYPE_ALERT:
369 			ret = -ENOTCONN;
370 			break;
371 		default:
372 			ret = -EAGAIN;
373 		}
374 	}
375 	return ret;
376 }
377 
378 static int
379 xs_sock_recv_cmsg(struct socket *sock, struct msghdr *msg, int flags)
380 {
381 	union {
382 		struct cmsghdr	cmsg;
383 		u8		buf[CMSG_SPACE(sizeof(u8))];
384 	} u;
385 	int ret;
386 
387 	msg->msg_control = &u;
388 	msg->msg_controllen = sizeof(u);
389 	ret = sock_recvmsg(sock, msg, flags);
390 	if (msg->msg_controllen != sizeof(u))
391 		ret = xs_sock_process_cmsg(sock, msg, &u.cmsg, ret);
392 	return ret;
393 }
394 
395 static ssize_t
396 xs_sock_recvmsg(struct socket *sock, struct msghdr *msg, int flags, size_t seek)
397 {
398 	ssize_t ret;
399 	if (seek != 0)
400 		iov_iter_advance(&msg->msg_iter, seek);
401 	ret = xs_sock_recv_cmsg(sock, msg, flags);
402 	return ret > 0 ? ret + seek : ret;
403 }
404 
405 static ssize_t
406 xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags,
407 		struct kvec *kvec, size_t count, size_t seek)
408 {
409 	iov_iter_kvec(&msg->msg_iter, ITER_DEST, kvec, 1, count);
410 	return xs_sock_recvmsg(sock, msg, flags, seek);
411 }
412 
413 static ssize_t
414 xs_read_bvec(struct socket *sock, struct msghdr *msg, int flags,
415 		struct bio_vec *bvec, unsigned long nr, size_t count,
416 		size_t seek)
417 {
418 	iov_iter_bvec(&msg->msg_iter, ITER_DEST, bvec, nr, count);
419 	return xs_sock_recvmsg(sock, msg, flags, seek);
420 }
421 
422 static ssize_t
423 xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
424 		size_t count)
425 {
426 	iov_iter_discard(&msg->msg_iter, ITER_DEST, count);
427 	return xs_sock_recv_cmsg(sock, msg, flags);
428 }
429 
430 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
431 static void
432 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
433 {
434 	struct bvec_iter bi = {
435 		.bi_size = count,
436 	};
437 	struct bio_vec bv;
438 
439 	bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
440 	for_each_bvec(bv, bvec, bi, bi)
441 		flush_dcache_page(bv.bv_page);
442 }
443 #else
444 static inline void
445 xs_flush_bvec(const struct bio_vec *bvec, size_t count, size_t seek)
446 {
447 }
448 #endif
449 
450 static ssize_t
451 xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
452 		struct xdr_buf *buf, size_t count, size_t seek, size_t *read)
453 {
454 	size_t want, seek_init = seek, offset = 0;
455 	ssize_t ret;
456 
457 	want = min_t(size_t, count, buf->head[0].iov_len);
458 	if (seek < want) {
459 		ret = xs_read_kvec(sock, msg, flags, &buf->head[0], want, seek);
460 		if (ret <= 0)
461 			goto sock_err;
462 		offset += ret;
463 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
464 			goto out;
465 		if (ret != want)
466 			goto out;
467 		seek = 0;
468 	} else {
469 		seek -= want;
470 		offset += want;
471 	}
472 
473 	want = xs_alloc_sparse_pages(
474 		buf, min_t(size_t, count - offset, buf->page_len),
475 		GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
476 	if (seek < want) {
477 		ret = xs_read_bvec(sock, msg, flags, buf->bvec,
478 				xdr_buf_pagecount(buf),
479 				want + buf->page_base,
480 				seek + buf->page_base);
481 		if (ret <= 0)
482 			goto sock_err;
483 		xs_flush_bvec(buf->bvec, ret, seek + buf->page_base);
484 		ret -= buf->page_base;
485 		offset += ret;
486 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
487 			goto out;
488 		if (ret != want)
489 			goto out;
490 		seek = 0;
491 	} else {
492 		seek -= want;
493 		offset += want;
494 	}
495 
496 	want = min_t(size_t, count - offset, buf->tail[0].iov_len);
497 	if (seek < want) {
498 		ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);
499 		if (ret <= 0)
500 			goto sock_err;
501 		offset += ret;
502 		if (offset == count || msg->msg_flags & (MSG_EOR|MSG_TRUNC))
503 			goto out;
504 		if (ret != want)
505 			goto out;
506 	} else if (offset < seek_init)
507 		offset = seek_init;
508 	ret = -EMSGSIZE;
509 out:
510 	*read = offset - seek_init;
511 	return ret;
512 sock_err:
513 	offset += seek;
514 	goto out;
515 }
516 
517 static void
518 xs_read_header(struct sock_xprt *transport, struct xdr_buf *buf)
519 {
520 	if (!transport->recv.copied) {
521 		if (buf->head[0].iov_len >= transport->recv.offset)
522 			memcpy(buf->head[0].iov_base,
523 					&transport->recv.xid,
524 					transport->recv.offset);
525 		transport->recv.copied = transport->recv.offset;
526 	}
527 }
528 
529 static bool
530 xs_read_stream_request_done(struct sock_xprt *transport)
531 {
532 	return transport->recv.fraghdr & cpu_to_be32(RPC_LAST_STREAM_FRAGMENT);
533 }
534 
535 static void
536 xs_read_stream_check_eor(struct sock_xprt *transport,
537 		struct msghdr *msg)
538 {
539 	if (xs_read_stream_request_done(transport))
540 		msg->msg_flags |= MSG_EOR;
541 }
542 
543 static ssize_t
544 xs_read_stream_request(struct sock_xprt *transport, struct msghdr *msg,
545 		int flags, struct rpc_rqst *req)
546 {
547 	struct xdr_buf *buf = &req->rq_private_buf;
548 	size_t want, read;
549 	ssize_t ret;
550 
551 	xs_read_header(transport, buf);
552 
553 	want = transport->recv.len - transport->recv.offset;
554 	if (want != 0) {
555 		ret = xs_read_xdr_buf(transport->sock, msg, flags, buf,
556 				transport->recv.copied + want,
557 				transport->recv.copied,
558 				&read);
559 		transport->recv.offset += read;
560 		transport->recv.copied += read;
561 	}
562 
563 	if (transport->recv.offset == transport->recv.len)
564 		xs_read_stream_check_eor(transport, msg);
565 
566 	if (want == 0)
567 		return 0;
568 
569 	switch (ret) {
570 	default:
571 		break;
572 	case -EFAULT:
573 	case -EMSGSIZE:
574 		msg->msg_flags |= MSG_TRUNC;
575 		return read;
576 	case 0:
577 		return -ESHUTDOWN;
578 	}
579 	return ret < 0 ? ret : read;
580 }
581 
582 static size_t
583 xs_read_stream_headersize(bool isfrag)
584 {
585 	if (isfrag)
586 		return sizeof(__be32);
587 	return 3 * sizeof(__be32);
588 }
589 
590 static ssize_t
591 xs_read_stream_header(struct sock_xprt *transport, struct msghdr *msg,
592 		int flags, size_t want, size_t seek)
593 {
594 	struct kvec kvec = {
595 		.iov_base = &transport->recv.fraghdr,
596 		.iov_len = want,
597 	};
598 	return xs_read_kvec(transport->sock, msg, flags, &kvec, want, seek);
599 }
600 
601 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
602 static ssize_t
603 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
604 {
605 	struct rpc_xprt *xprt = &transport->xprt;
606 	struct rpc_rqst *req;
607 	ssize_t ret;
608 
609 	/* Is this transport associated with the backchannel? */
610 	if (!xprt->bc_serv)
611 		return -ESHUTDOWN;
612 
613 	/* Look up and lock the request corresponding to the given XID */
614 	req = xprt_lookup_bc_request(xprt, transport->recv.xid);
615 	if (!req) {
616 		printk(KERN_WARNING "Callback slot table overflowed\n");
617 		return -ESHUTDOWN;
618 	}
619 	if (transport->recv.copied && !req->rq_private_buf.len)
620 		return -ESHUTDOWN;
621 
622 	ret = xs_read_stream_request(transport, msg, flags, req);
623 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
624 		xprt_complete_bc_request(req, transport->recv.copied);
625 	else
626 		req->rq_private_buf.len = transport->recv.copied;
627 
628 	return ret;
629 }
630 #else /* CONFIG_SUNRPC_BACKCHANNEL */
631 static ssize_t
632 xs_read_stream_call(struct sock_xprt *transport, struct msghdr *msg, int flags)
633 {
634 	return -ESHUTDOWN;
635 }
636 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
637 
638 static ssize_t
639 xs_read_stream_reply(struct sock_xprt *transport, struct msghdr *msg, int flags)
640 {
641 	struct rpc_xprt *xprt = &transport->xprt;
642 	struct rpc_rqst *req;
643 	ssize_t ret = 0;
644 
645 	/* Look up and lock the request corresponding to the given XID */
646 	spin_lock(&xprt->queue_lock);
647 	req = xprt_lookup_rqst(xprt, transport->recv.xid);
648 	if (!req || (transport->recv.copied && !req->rq_private_buf.len)) {
649 		msg->msg_flags |= MSG_TRUNC;
650 		goto out;
651 	}
652 	xprt_pin_rqst(req);
653 	spin_unlock(&xprt->queue_lock);
654 
655 	ret = xs_read_stream_request(transport, msg, flags, req);
656 
657 	spin_lock(&xprt->queue_lock);
658 	if (msg->msg_flags & (MSG_EOR|MSG_TRUNC))
659 		xprt_complete_rqst(req->rq_task, transport->recv.copied);
660 	else
661 		req->rq_private_buf.len = transport->recv.copied;
662 	xprt_unpin_rqst(req);
663 out:
664 	spin_unlock(&xprt->queue_lock);
665 	return ret;
666 }
667 
668 static ssize_t
669 xs_read_stream(struct sock_xprt *transport, int flags)
670 {
671 	struct msghdr msg = { 0 };
672 	size_t want, read = 0;
673 	ssize_t ret = 0;
674 
675 	if (transport->recv.len == 0) {
676 		want = xs_read_stream_headersize(transport->recv.copied != 0);
677 		ret = xs_read_stream_header(transport, &msg, flags, want,
678 				transport->recv.offset);
679 		if (ret <= 0)
680 			goto out_err;
681 		transport->recv.offset = ret;
682 		if (transport->recv.offset != want)
683 			return transport->recv.offset;
684 		transport->recv.len = be32_to_cpu(transport->recv.fraghdr) &
685 			RPC_FRAGMENT_SIZE_MASK;
686 		transport->recv.offset -= sizeof(transport->recv.fraghdr);
687 		read = ret;
688 	}
689 
690 	switch (be32_to_cpu(transport->recv.calldir)) {
691 	default:
692 		msg.msg_flags |= MSG_TRUNC;
693 		break;
694 	case RPC_CALL:
695 		ret = xs_read_stream_call(transport, &msg, flags);
696 		break;
697 	case RPC_REPLY:
698 		ret = xs_read_stream_reply(transport, &msg, flags);
699 	}
700 	if (msg.msg_flags & MSG_TRUNC) {
701 		transport->recv.calldir = cpu_to_be32(-1);
702 		transport->recv.copied = -1;
703 	}
704 	if (ret < 0)
705 		goto out_err;
706 	read += ret;
707 	if (transport->recv.offset < transport->recv.len) {
708 		if (!(msg.msg_flags & MSG_TRUNC))
709 			return read;
710 		msg.msg_flags = 0;
711 		ret = xs_read_discard(transport->sock, &msg, flags,
712 				transport->recv.len - transport->recv.offset);
713 		if (ret <= 0)
714 			goto out_err;
715 		transport->recv.offset += ret;
716 		read += ret;
717 		if (transport->recv.offset != transport->recv.len)
718 			return read;
719 	}
720 	if (xs_read_stream_request_done(transport)) {
721 		trace_xs_stream_read_request(transport);
722 		transport->recv.copied = 0;
723 	}
724 	transport->recv.offset = 0;
725 	transport->recv.len = 0;
726 	return read;
727 out_err:
728 	return ret != 0 ? ret : -ESHUTDOWN;
729 }
730 
731 static __poll_t xs_poll_socket(struct sock_xprt *transport)
732 {
733 	return transport->sock->ops->poll(transport->file, transport->sock,
734 			NULL);
735 }
736 
737 static bool xs_poll_socket_readable(struct sock_xprt *transport)
738 {
739 	__poll_t events = xs_poll_socket(transport);
740 
741 	return (events & (EPOLLIN | EPOLLRDNORM)) && !(events & EPOLLRDHUP);
742 }
743 
744 static void xs_poll_check_readable(struct sock_xprt *transport)
745 {
746 
747 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
748 	if (test_bit(XPRT_SOCK_IGNORE_RECV, &transport->sock_state))
749 		return;
750 	if (!xs_poll_socket_readable(transport))
751 		return;
752 	if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
753 		queue_work(xprtiod_workqueue, &transport->recv_worker);
754 }
755 
756 static void xs_stream_data_receive(struct sock_xprt *transport)
757 {
758 	size_t read = 0;
759 	ssize_t ret = 0;
760 
761 	mutex_lock(&transport->recv_mutex);
762 	if (transport->sock == NULL)
763 		goto out;
764 	for (;;) {
765 		ret = xs_read_stream(transport, MSG_DONTWAIT);
766 		if (ret < 0)
767 			break;
768 		read += ret;
769 		cond_resched();
770 	}
771 	if (ret == -ESHUTDOWN)
772 		kernel_sock_shutdown(transport->sock, SHUT_RDWR);
773 	else
774 		xs_poll_check_readable(transport);
775 out:
776 	mutex_unlock(&transport->recv_mutex);
777 	trace_xs_stream_read_data(&transport->xprt, ret, read);
778 }
779 
780 static void xs_stream_data_receive_workfn(struct work_struct *work)
781 {
782 	struct sock_xprt *transport =
783 		container_of(work, struct sock_xprt, recv_worker);
784 	unsigned int pflags = memalloc_nofs_save();
785 
786 	xs_stream_data_receive(transport);
787 	memalloc_nofs_restore(pflags);
788 }
789 
790 static void
791 xs_stream_reset_connect(struct sock_xprt *transport)
792 {
793 	transport->recv.offset = 0;
794 	transport->recv.len = 0;
795 	transport->recv.copied = 0;
796 	transport->xmit.offset = 0;
797 }
798 
799 static void
800 xs_stream_start_connect(struct sock_xprt *transport)
801 {
802 	transport->xprt.stat.connect_count++;
803 	transport->xprt.stat.connect_start = jiffies;
804 }
805 
806 #define XS_SENDMSG_FLAGS	(MSG_DONTWAIT | MSG_NOSIGNAL)
807 
808 /**
809  * xs_nospace - handle transmit was incomplete
810  * @req: pointer to RPC request
811  * @transport: pointer to struct sock_xprt
812  *
813  */
814 static int xs_nospace(struct rpc_rqst *req, struct sock_xprt *transport)
815 {
816 	struct rpc_xprt *xprt = &transport->xprt;
817 	struct sock *sk = transport->inet;
818 	int ret = -EAGAIN;
819 
820 	trace_rpc_socket_nospace(req, transport);
821 
822 	/* Protect against races with write_space */
823 	spin_lock(&xprt->transport_lock);
824 
825 	/* Don't race with disconnect */
826 	if (xprt_connected(xprt)) {
827 		/* wait for more buffer space */
828 		set_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
829 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
830 		sk->sk_write_pending++;
831 		xprt_wait_for_buffer_space(xprt);
832 	} else
833 		ret = -ENOTCONN;
834 
835 	spin_unlock(&xprt->transport_lock);
836 	return ret;
837 }
838 
839 static int xs_sock_nospace(struct rpc_rqst *req)
840 {
841 	struct sock_xprt *transport =
842 		container_of(req->rq_xprt, struct sock_xprt, xprt);
843 	struct sock *sk = transport->inet;
844 	int ret = -EAGAIN;
845 
846 	lock_sock(sk);
847 	if (!sock_writeable(sk))
848 		ret = xs_nospace(req, transport);
849 	release_sock(sk);
850 	return ret;
851 }
852 
853 static int xs_stream_nospace(struct rpc_rqst *req, bool vm_wait)
854 {
855 	struct sock_xprt *transport =
856 		container_of(req->rq_xprt, struct sock_xprt, xprt);
857 	struct sock *sk = transport->inet;
858 	int ret = -EAGAIN;
859 
860 	if (vm_wait)
861 		return -ENOBUFS;
862 	lock_sock(sk);
863 	if (!sk_stream_memory_free(sk))
864 		ret = xs_nospace(req, transport);
865 	release_sock(sk);
866 	return ret;
867 }
868 
869 static int xs_stream_prepare_request(struct rpc_rqst *req, struct xdr_buf *buf)
870 {
871 	return xdr_alloc_bvec(buf, rpc_task_gfp_mask());
872 }
873 
874 /*
875  * Determine if the previous message in the stream was aborted before it
876  * could complete transmission.
877  */
878 static bool
879 xs_send_request_was_aborted(struct sock_xprt *transport, struct rpc_rqst *req)
880 {
881 	return transport->xmit.offset != 0 && req->rq_bytes_sent == 0;
882 }
883 
884 /*
885  * Return the stream record marker field for a record of length < 2^31-1
886  */
887 static rpc_fraghdr
888 xs_stream_record_marker(struct xdr_buf *xdr)
889 {
890 	if (!xdr->len)
891 		return 0;
892 	return cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | (u32)xdr->len);
893 }
894 
895 /**
896  * xs_local_send_request - write an RPC request to an AF_LOCAL socket
897  * @req: pointer to RPC request
898  *
899  * Return values:
900  *        0:	The request has been sent
901  *   EAGAIN:	The socket was blocked, please call again later to
902  *		complete the request
903  * ENOTCONN:	Caller needs to invoke connect logic then call again
904  *    other:	Some other error occurred, the request was not sent
905  */
906 static int xs_local_send_request(struct rpc_rqst *req)
907 {
908 	struct rpc_xprt *xprt = req->rq_xprt;
909 	struct sock_xprt *transport =
910 				container_of(xprt, struct sock_xprt, xprt);
911 	struct xdr_buf *xdr = &req->rq_snd_buf;
912 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
913 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
914 	struct msghdr msg = {
915 		.msg_flags	= XS_SENDMSG_FLAGS,
916 	};
917 	bool vm_wait;
918 	unsigned int sent;
919 	int status;
920 
921 	/* Close the stream if the previous transmission was incomplete */
922 	if (xs_send_request_was_aborted(transport, req)) {
923 		xprt_force_disconnect(xprt);
924 		return -ENOTCONN;
925 	}
926 
927 	xs_pktdump("packet data:",
928 			req->rq_svec->iov_base, req->rq_svec->iov_len);
929 
930 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
931 
932 	req->rq_xtime = ktime_get();
933 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
934 				   transport->xmit.offset, rm, &sent);
935 	dprintk("RPC:       %s(%u) = %d\n",
936 			__func__, xdr->len - transport->xmit.offset, status);
937 
938 	if (likely(sent > 0) || status == 0) {
939 		transport->xmit.offset += sent;
940 		req->rq_bytes_sent = transport->xmit.offset;
941 		if (likely(req->rq_bytes_sent >= msglen)) {
942 			req->rq_xmit_bytes_sent += transport->xmit.offset;
943 			transport->xmit.offset = 0;
944 			return 0;
945 		}
946 		status = -EAGAIN;
947 		vm_wait = false;
948 	}
949 
950 	switch (status) {
951 	case -EAGAIN:
952 		status = xs_stream_nospace(req, vm_wait);
953 		break;
954 	default:
955 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
956 			-status);
957 		fallthrough;
958 	case -EPIPE:
959 		xprt_force_disconnect(xprt);
960 		status = -ENOTCONN;
961 	}
962 
963 	return status;
964 }
965 
966 /**
967  * xs_udp_send_request - write an RPC request to a UDP socket
968  * @req: pointer to RPC request
969  *
970  * Return values:
971  *        0:	The request has been sent
972  *   EAGAIN:	The socket was blocked, please call again later to
973  *		complete the request
974  * ENOTCONN:	Caller needs to invoke connect logic then call again
975  *    other:	Some other error occurred, the request was not sent
976  */
977 static int xs_udp_send_request(struct rpc_rqst *req)
978 {
979 	struct rpc_xprt *xprt = req->rq_xprt;
980 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
981 	struct xdr_buf *xdr = &req->rq_snd_buf;
982 	struct msghdr msg = {
983 		.msg_name	= xs_addr(xprt),
984 		.msg_namelen	= xprt->addrlen,
985 		.msg_flags	= XS_SENDMSG_FLAGS,
986 	};
987 	unsigned int sent;
988 	int status;
989 
990 	xs_pktdump("packet data:",
991 				req->rq_svec->iov_base,
992 				req->rq_svec->iov_len);
993 
994 	if (!xprt_bound(xprt))
995 		return -ENOTCONN;
996 
997 	if (!xprt_request_get_cong(xprt, req))
998 		return -EBADSLT;
999 
1000 	status = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
1001 	if (status < 0)
1002 		return status;
1003 	req->rq_xtime = ktime_get();
1004 	status = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, 0, &sent);
1005 
1006 	dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
1007 			xdr->len, status);
1008 
1009 	/* firewall is blocking us, don't return -EAGAIN or we end up looping */
1010 	if (status == -EPERM)
1011 		goto process_status;
1012 
1013 	if (status == -EAGAIN && sock_writeable(transport->inet))
1014 		status = -ENOBUFS;
1015 
1016 	if (sent > 0 || status == 0) {
1017 		req->rq_xmit_bytes_sent += sent;
1018 		if (sent >= req->rq_slen)
1019 			return 0;
1020 		/* Still some bytes left; set up for a retry later. */
1021 		status = -EAGAIN;
1022 	}
1023 
1024 process_status:
1025 	switch (status) {
1026 	case -ENOTSOCK:
1027 		status = -ENOTCONN;
1028 		/* Should we call xs_close() here? */
1029 		break;
1030 	case -EAGAIN:
1031 		status = xs_sock_nospace(req);
1032 		break;
1033 	case -ENETUNREACH:
1034 	case -ENOBUFS:
1035 	case -EPIPE:
1036 	case -ECONNREFUSED:
1037 	case -EPERM:
1038 		/* When the server has died, an ICMP port unreachable message
1039 		 * prompts ECONNREFUSED. */
1040 		break;
1041 	default:
1042 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1043 			-status);
1044 	}
1045 
1046 	return status;
1047 }
1048 
1049 /**
1050  * xs_tcp_send_request - write an RPC request to a TCP socket
1051  * @req: pointer to RPC request
1052  *
1053  * Return values:
1054  *        0:	The request has been sent
1055  *   EAGAIN:	The socket was blocked, please call again later to
1056  *		complete the request
1057  * ENOTCONN:	Caller needs to invoke connect logic then call again
1058  *    other:	Some other error occurred, the request was not sent
1059  *
1060  * XXX: In the case of soft timeouts, should we eventually give up
1061  *	if sendmsg is not able to make progress?
1062  */
1063 static int xs_tcp_send_request(struct rpc_rqst *req)
1064 {
1065 	struct rpc_xprt *xprt = req->rq_xprt;
1066 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1067 	struct xdr_buf *xdr = &req->rq_snd_buf;
1068 	rpc_fraghdr rm = xs_stream_record_marker(xdr);
1069 	unsigned int msglen = rm ? req->rq_slen + sizeof(rm) : req->rq_slen;
1070 	struct msghdr msg = {
1071 		.msg_flags	= XS_SENDMSG_FLAGS,
1072 	};
1073 	bool vm_wait;
1074 	unsigned int sent;
1075 	int status;
1076 
1077 	/* Close the stream if the previous transmission was incomplete */
1078 	if (xs_send_request_was_aborted(transport, req)) {
1079 		if (transport->sock != NULL)
1080 			kernel_sock_shutdown(transport->sock, SHUT_RDWR);
1081 		return -ENOTCONN;
1082 	}
1083 	if (!transport->inet)
1084 		return -ENOTCONN;
1085 
1086 	xs_pktdump("packet data:",
1087 				req->rq_svec->iov_base,
1088 				req->rq_svec->iov_len);
1089 
1090 	if (test_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state))
1091 		xs_tcp_set_socket_timeouts(xprt, transport->sock);
1092 
1093 	xs_set_srcport(transport, transport->sock);
1094 
1095 	/* Continue transmitting the packet/record. We must be careful
1096 	 * to cope with writespace callbacks arriving _after_ we have
1097 	 * called sendmsg(). */
1098 	req->rq_xtime = ktime_get();
1099 	tcp_sock_set_cork(transport->inet, true);
1100 
1101 	vm_wait = sk_stream_is_writeable(transport->inet) ? true : false;
1102 
1103 	do {
1104 		status = xprt_sock_sendmsg(transport->sock, &msg, xdr,
1105 					   transport->xmit.offset, rm, &sent);
1106 
1107 		dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
1108 				xdr->len - transport->xmit.offset, status);
1109 
1110 		/* If we've sent the entire packet, immediately
1111 		 * reset the count of bytes sent. */
1112 		transport->xmit.offset += sent;
1113 		req->rq_bytes_sent = transport->xmit.offset;
1114 		if (likely(req->rq_bytes_sent >= msglen)) {
1115 			req->rq_xmit_bytes_sent += transport->xmit.offset;
1116 			transport->xmit.offset = 0;
1117 			if (atomic_long_read(&xprt->xmit_queuelen) == 1)
1118 				tcp_sock_set_cork(transport->inet, false);
1119 			return 0;
1120 		}
1121 
1122 		WARN_ON_ONCE(sent == 0 && status == 0);
1123 
1124 		if (sent > 0)
1125 			vm_wait = false;
1126 
1127 	} while (status == 0);
1128 
1129 	switch (status) {
1130 	case -ENOTSOCK:
1131 		status = -ENOTCONN;
1132 		/* Should we call xs_close() here? */
1133 		break;
1134 	case -EAGAIN:
1135 		status = xs_stream_nospace(req, vm_wait);
1136 		break;
1137 	case -ECONNRESET:
1138 	case -ECONNREFUSED:
1139 	case -ENOTCONN:
1140 	case -EADDRINUSE:
1141 	case -ENOBUFS:
1142 	case -EPIPE:
1143 		break;
1144 	default:
1145 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
1146 			-status);
1147 	}
1148 
1149 	return status;
1150 }
1151 
1152 static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1153 {
1154 	transport->old_data_ready = sk->sk_data_ready;
1155 	transport->old_state_change = sk->sk_state_change;
1156 	transport->old_write_space = sk->sk_write_space;
1157 	transport->old_error_report = sk->sk_error_report;
1158 }
1159 
1160 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
1161 {
1162 	sk->sk_data_ready = transport->old_data_ready;
1163 	sk->sk_state_change = transport->old_state_change;
1164 	sk->sk_write_space = transport->old_write_space;
1165 	sk->sk_error_report = transport->old_error_report;
1166 }
1167 
1168 static void xs_sock_reset_state_flags(struct rpc_xprt *xprt)
1169 {
1170 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1171 
1172 	clear_bit(XPRT_SOCK_DATA_READY, &transport->sock_state);
1173 	clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state);
1174 	clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state);
1175 	clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state);
1176 	clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state);
1177 }
1178 
1179 static void xs_run_error_worker(struct sock_xprt *transport, unsigned int nr)
1180 {
1181 	set_bit(nr, &transport->sock_state);
1182 	queue_work(xprtiod_workqueue, &transport->error_worker);
1183 }
1184 
1185 static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
1186 {
1187 	xprt->connect_cookie++;
1188 	smp_mb__before_atomic();
1189 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1190 	clear_bit(XPRT_CLOSING, &xprt->state);
1191 	xs_sock_reset_state_flags(xprt);
1192 	smp_mb__after_atomic();
1193 }
1194 
1195 /**
1196  * xs_error_report - callback to handle TCP socket state errors
1197  * @sk: socket
1198  *
1199  * Note: we don't call sock_error() since there may be a rpc_task
1200  * using the socket, and so we don't want to clear sk->sk_err.
1201  */
1202 static void xs_error_report(struct sock *sk)
1203 {
1204 	struct sock_xprt *transport;
1205 	struct rpc_xprt *xprt;
1206 
1207 	if (!(xprt = xprt_from_sock(sk)))
1208 		return;
1209 
1210 	transport = container_of(xprt, struct sock_xprt, xprt);
1211 	transport->xprt_err = -sk->sk_err;
1212 	if (transport->xprt_err == 0)
1213 		return;
1214 	dprintk("RPC:       xs_error_report client %p, error=%d...\n",
1215 			xprt, -transport->xprt_err);
1216 	trace_rpc_socket_error(xprt, sk->sk_socket, transport->xprt_err);
1217 
1218 	/* barrier ensures xprt_err is set before XPRT_SOCK_WAKE_ERROR */
1219 	smp_mb__before_atomic();
1220 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_ERROR);
1221 }
1222 
1223 static void xs_reset_transport(struct sock_xprt *transport)
1224 {
1225 	struct socket *sock = transport->sock;
1226 	struct sock *sk = transport->inet;
1227 	struct rpc_xprt *xprt = &transport->xprt;
1228 	struct file *filp = transport->file;
1229 
1230 	if (sk == NULL)
1231 		return;
1232 	/*
1233 	 * Make sure we're calling this in a context from which it is safe
1234 	 * to call __fput_sync(). In practice that means rpciod and the
1235 	 * system workqueue.
1236 	 */
1237 	if (!(current->flags & PF_WQ_WORKER)) {
1238 		WARN_ON_ONCE(1);
1239 		set_bit(XPRT_CLOSE_WAIT, &xprt->state);
1240 		return;
1241 	}
1242 
1243 	if (atomic_read(&transport->xprt.swapper))
1244 		sk_clear_memalloc(sk);
1245 
1246 	kernel_sock_shutdown(sock, SHUT_RDWR);
1247 
1248 	mutex_lock(&transport->recv_mutex);
1249 	lock_sock(sk);
1250 	transport->inet = NULL;
1251 	transport->sock = NULL;
1252 	transport->file = NULL;
1253 
1254 	sk->sk_user_data = NULL;
1255 
1256 	xs_restore_old_callbacks(transport, sk);
1257 	xprt_clear_connected(xprt);
1258 	xs_sock_reset_connection_flags(xprt);
1259 	/* Reset stream record info */
1260 	xs_stream_reset_connect(transport);
1261 	release_sock(sk);
1262 	mutex_unlock(&transport->recv_mutex);
1263 
1264 	trace_rpc_socket_close(xprt, sock);
1265 	__fput_sync(filp);
1266 
1267 	xprt_disconnect_done(xprt);
1268 }
1269 
1270 /**
1271  * xs_close - close a socket
1272  * @xprt: transport
1273  *
1274  * This is used when all requests are complete; ie, no DRC state remains
1275  * on the server we want to save.
1276  *
1277  * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
1278  * xs_reset_transport() zeroing the socket from underneath a writer.
1279  */
1280 static void xs_close(struct rpc_xprt *xprt)
1281 {
1282 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1283 
1284 	dprintk("RPC:       xs_close xprt %p\n", xprt);
1285 
1286 	xs_reset_transport(transport);
1287 	xprt->reestablish_timeout = 0;
1288 }
1289 
1290 static void xs_inject_disconnect(struct rpc_xprt *xprt)
1291 {
1292 	dprintk("RPC:       injecting transport disconnect on xprt=%p\n",
1293 		xprt);
1294 	xprt_disconnect_done(xprt);
1295 }
1296 
1297 static void xs_xprt_free(struct rpc_xprt *xprt)
1298 {
1299 	xs_free_peer_addresses(xprt);
1300 	xprt_free(xprt);
1301 }
1302 
1303 /**
1304  * xs_destroy - prepare to shutdown a transport
1305  * @xprt: doomed transport
1306  *
1307  */
1308 static void xs_destroy(struct rpc_xprt *xprt)
1309 {
1310 	struct sock_xprt *transport = container_of(xprt,
1311 			struct sock_xprt, xprt);
1312 	dprintk("RPC:       xs_destroy xprt %p\n", xprt);
1313 
1314 	cancel_delayed_work_sync(&transport->connect_worker);
1315 	xs_close(xprt);
1316 	cancel_work_sync(&transport->recv_worker);
1317 	cancel_work_sync(&transport->error_worker);
1318 	xs_xprt_free(xprt);
1319 	module_put(THIS_MODULE);
1320 }
1321 
1322 /**
1323  * xs_udp_data_read_skb - receive callback for UDP sockets
1324  * @xprt: transport
1325  * @sk: socket
1326  * @skb: skbuff
1327  *
1328  */
1329 static void xs_udp_data_read_skb(struct rpc_xprt *xprt,
1330 		struct sock *sk,
1331 		struct sk_buff *skb)
1332 {
1333 	struct rpc_task *task;
1334 	struct rpc_rqst *rovr;
1335 	int repsize, copied;
1336 	u32 _xid;
1337 	__be32 *xp;
1338 
1339 	repsize = skb->len;
1340 	if (repsize < 4) {
1341 		dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
1342 		return;
1343 	}
1344 
1345 	/* Copy the XID from the skb... */
1346 	xp = skb_header_pointer(skb, 0, sizeof(_xid), &_xid);
1347 	if (xp == NULL)
1348 		return;
1349 
1350 	/* Look up and lock the request corresponding to the given XID */
1351 	spin_lock(&xprt->queue_lock);
1352 	rovr = xprt_lookup_rqst(xprt, *xp);
1353 	if (!rovr)
1354 		goto out_unlock;
1355 	xprt_pin_rqst(rovr);
1356 	xprt_update_rtt(rovr->rq_task);
1357 	spin_unlock(&xprt->queue_lock);
1358 	task = rovr->rq_task;
1359 
1360 	if ((copied = rovr->rq_private_buf.buflen) > repsize)
1361 		copied = repsize;
1362 
1363 	/* Suck it into the iovec, verify checksum if not done by hw. */
1364 	if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
1365 		spin_lock(&xprt->queue_lock);
1366 		__UDPX_INC_STATS(sk, UDP_MIB_INERRORS);
1367 		goto out_unpin;
1368 	}
1369 
1370 
1371 	spin_lock(&xprt->transport_lock);
1372 	xprt_adjust_cwnd(xprt, task, copied);
1373 	spin_unlock(&xprt->transport_lock);
1374 	spin_lock(&xprt->queue_lock);
1375 	xprt_complete_rqst(task, copied);
1376 	__UDPX_INC_STATS(sk, UDP_MIB_INDATAGRAMS);
1377 out_unpin:
1378 	xprt_unpin_rqst(rovr);
1379  out_unlock:
1380 	spin_unlock(&xprt->queue_lock);
1381 }
1382 
1383 static void xs_udp_data_receive(struct sock_xprt *transport)
1384 {
1385 	struct sk_buff *skb;
1386 	struct sock *sk;
1387 	int err;
1388 
1389 	mutex_lock(&transport->recv_mutex);
1390 	sk = transport->inet;
1391 	if (sk == NULL)
1392 		goto out;
1393 	for (;;) {
1394 		skb = skb_recv_udp(sk, MSG_DONTWAIT, &err);
1395 		if (skb == NULL)
1396 			break;
1397 		xs_udp_data_read_skb(&transport->xprt, sk, skb);
1398 		consume_skb(skb);
1399 		cond_resched();
1400 	}
1401 	xs_poll_check_readable(transport);
1402 out:
1403 	mutex_unlock(&transport->recv_mutex);
1404 }
1405 
1406 static void xs_udp_data_receive_workfn(struct work_struct *work)
1407 {
1408 	struct sock_xprt *transport =
1409 		container_of(work, struct sock_xprt, recv_worker);
1410 	unsigned int pflags = memalloc_nofs_save();
1411 
1412 	xs_udp_data_receive(transport);
1413 	memalloc_nofs_restore(pflags);
1414 }
1415 
1416 /**
1417  * xs_data_ready - "data ready" callback for sockets
1418  * @sk: socket with data to read
1419  *
1420  */
1421 static void xs_data_ready(struct sock *sk)
1422 {
1423 	struct rpc_xprt *xprt;
1424 
1425 	trace_sk_data_ready(sk);
1426 
1427 	xprt = xprt_from_sock(sk);
1428 	if (xprt != NULL) {
1429 		struct sock_xprt *transport = container_of(xprt,
1430 				struct sock_xprt, xprt);
1431 
1432 		trace_xs_data_ready(xprt);
1433 
1434 		transport->old_data_ready(sk);
1435 
1436 		if (test_bit(XPRT_SOCK_IGNORE_RECV, &transport->sock_state))
1437 			return;
1438 
1439 		/* Any data means we had a useful conversation, so
1440 		 * then we don't need to delay the next reconnect
1441 		 */
1442 		if (xprt->reestablish_timeout)
1443 			xprt->reestablish_timeout = 0;
1444 		if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state))
1445 			queue_work(xprtiod_workqueue, &transport->recv_worker);
1446 	}
1447 }
1448 
1449 /*
1450  * Helper function to force a TCP close if the server is sending
1451  * junk and/or it has put us in CLOSE_WAIT
1452  */
1453 static void xs_tcp_force_close(struct rpc_xprt *xprt)
1454 {
1455 	xprt_force_disconnect(xprt);
1456 }
1457 
1458 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1459 static size_t xs_tcp_bc_maxpayload(struct rpc_xprt *xprt)
1460 {
1461 	return PAGE_SIZE;
1462 }
1463 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1464 
1465 /**
1466  * xs_local_state_change - callback to handle AF_LOCAL socket state changes
1467  * @sk: socket whose state has changed
1468  *
1469  */
1470 static void xs_local_state_change(struct sock *sk)
1471 {
1472 	struct rpc_xprt *xprt;
1473 	struct sock_xprt *transport;
1474 
1475 	if (!(xprt = xprt_from_sock(sk)))
1476 		return;
1477 	transport = container_of(xprt, struct sock_xprt, xprt);
1478 	if (sk->sk_shutdown & SHUTDOWN_MASK) {
1479 		clear_bit(XPRT_CONNECTED, &xprt->state);
1480 		/* Trigger the socket release */
1481 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1482 	}
1483 }
1484 
1485 /**
1486  * xs_tcp_state_change - callback to handle TCP socket state changes
1487  * @sk: socket whose state has changed
1488  *
1489  */
1490 static void xs_tcp_state_change(struct sock *sk)
1491 {
1492 	struct rpc_xprt *xprt;
1493 	struct sock_xprt *transport;
1494 
1495 	if (!(xprt = xprt_from_sock(sk)))
1496 		return;
1497 	dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
1498 	dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
1499 			sk->sk_state, xprt_connected(xprt),
1500 			sock_flag(sk, SOCK_DEAD),
1501 			sock_flag(sk, SOCK_ZAPPED),
1502 			sk->sk_shutdown);
1503 
1504 	transport = container_of(xprt, struct sock_xprt, xprt);
1505 	trace_rpc_socket_state_change(xprt, sk->sk_socket);
1506 	switch (sk->sk_state) {
1507 	case TCP_ESTABLISHED:
1508 		if (!xprt_test_and_set_connected(xprt)) {
1509 			xprt->connect_cookie++;
1510 			clear_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
1511 			xprt_clear_connecting(xprt);
1512 
1513 			xprt->stat.connect_count++;
1514 			xprt->stat.connect_time += (long)jiffies -
1515 						   xprt->stat.connect_start;
1516 			xs_run_error_worker(transport, XPRT_SOCK_WAKE_PENDING);
1517 		}
1518 		break;
1519 	case TCP_FIN_WAIT1:
1520 		/* The client initiated a shutdown of the socket */
1521 		xprt->connect_cookie++;
1522 		xprt->reestablish_timeout = 0;
1523 		set_bit(XPRT_CLOSING, &xprt->state);
1524 		smp_mb__before_atomic();
1525 		clear_bit(XPRT_CONNECTED, &xprt->state);
1526 		clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
1527 		smp_mb__after_atomic();
1528 		break;
1529 	case TCP_CLOSE_WAIT:
1530 		/* The server initiated a shutdown of the socket */
1531 		xprt->connect_cookie++;
1532 		clear_bit(XPRT_CONNECTED, &xprt->state);
1533 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1534 		fallthrough;
1535 	case TCP_CLOSING:
1536 		/*
1537 		 * If the server closed down the connection, make sure that
1538 		 * we back off before reconnecting
1539 		 */
1540 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
1541 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1542 		break;
1543 	case TCP_LAST_ACK:
1544 		set_bit(XPRT_CLOSING, &xprt->state);
1545 		smp_mb__before_atomic();
1546 		clear_bit(XPRT_CONNECTED, &xprt->state);
1547 		smp_mb__after_atomic();
1548 		break;
1549 	case TCP_CLOSE:
1550 		if (test_and_clear_bit(XPRT_SOCK_CONNECTING,
1551 					&transport->sock_state))
1552 			xprt_clear_connecting(xprt);
1553 		clear_bit(XPRT_CLOSING, &xprt->state);
1554 		/* Trigger the socket release */
1555 		xs_run_error_worker(transport, XPRT_SOCK_WAKE_DISCONNECT);
1556 	}
1557 }
1558 
1559 static void xs_write_space(struct sock *sk)
1560 {
1561 	struct sock_xprt *transport;
1562 	struct rpc_xprt *xprt;
1563 
1564 	if (!sk->sk_socket)
1565 		return;
1566 	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
1567 
1568 	if (unlikely(!(xprt = xprt_from_sock(sk))))
1569 		return;
1570 	transport = container_of(xprt, struct sock_xprt, xprt);
1571 	if (!test_and_clear_bit(XPRT_SOCK_NOSPACE, &transport->sock_state))
1572 		return;
1573 	xs_run_error_worker(transport, XPRT_SOCK_WAKE_WRITE);
1574 	sk->sk_write_pending--;
1575 }
1576 
1577 /**
1578  * xs_udp_write_space - callback invoked when socket buffer space
1579  *                             becomes available
1580  * @sk: socket whose state has changed
1581  *
1582  * Called when more output buffer space is available for this socket.
1583  * We try not to wake our writers until they can make "significant"
1584  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1585  * with a bunch of small requests.
1586  */
1587 static void xs_udp_write_space(struct sock *sk)
1588 {
1589 	/* from net/core/sock.c:sock_def_write_space */
1590 	if (sock_writeable(sk))
1591 		xs_write_space(sk);
1592 }
1593 
1594 /**
1595  * xs_tcp_write_space - callback invoked when socket buffer space
1596  *                             becomes available
1597  * @sk: socket whose state has changed
1598  *
1599  * Called when more output buffer space is available for this socket.
1600  * We try not to wake our writers until they can make "significant"
1601  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
1602  * with a bunch of small requests.
1603  */
1604 static void xs_tcp_write_space(struct sock *sk)
1605 {
1606 	/* from net/core/stream.c:sk_stream_write_space */
1607 	if (sk_stream_is_writeable(sk))
1608 		xs_write_space(sk);
1609 }
1610 
1611 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
1612 {
1613 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1614 	struct sock *sk = transport->inet;
1615 
1616 	if (transport->rcvsize) {
1617 		sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1618 		sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
1619 	}
1620 	if (transport->sndsize) {
1621 		sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1622 		sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
1623 		sk->sk_write_space(sk);
1624 	}
1625 }
1626 
1627 /**
1628  * xs_udp_set_buffer_size - set send and receive limits
1629  * @xprt: generic transport
1630  * @sndsize: requested size of send buffer, in bytes
1631  * @rcvsize: requested size of receive buffer, in bytes
1632  *
1633  * Set socket send and receive buffer size limits.
1634  */
1635 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
1636 {
1637 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
1638 
1639 	transport->sndsize = 0;
1640 	if (sndsize)
1641 		transport->sndsize = sndsize + 1024;
1642 	transport->rcvsize = 0;
1643 	if (rcvsize)
1644 		transport->rcvsize = rcvsize + 1024;
1645 
1646 	xs_udp_do_set_buffer_size(xprt);
1647 }
1648 
1649 /**
1650  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
1651  * @xprt: controlling transport
1652  * @task: task that timed out
1653  *
1654  * Adjust the congestion window after a retransmit timeout has occurred.
1655  */
1656 static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
1657 {
1658 	spin_lock(&xprt->transport_lock);
1659 	xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
1660 	spin_unlock(&xprt->transport_lock);
1661 }
1662 
1663 static int xs_get_random_port(void)
1664 {
1665 	unsigned short min = xprt_min_resvport, max = xprt_max_resvport;
1666 	unsigned short range;
1667 	unsigned short rand;
1668 
1669 	if (max < min)
1670 		return -EADDRINUSE;
1671 	range = max - min + 1;
1672 	rand = get_random_u32_below(range);
1673 	return rand + min;
1674 }
1675 
1676 static unsigned short xs_sock_getport(struct socket *sock)
1677 {
1678 	struct sockaddr_storage buf;
1679 	unsigned short port = 0;
1680 
1681 	if (kernel_getsockname(sock, (struct sockaddr *)&buf) < 0)
1682 		goto out;
1683 	switch (buf.ss_family) {
1684 	case AF_INET6:
1685 		port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
1686 		break;
1687 	case AF_INET:
1688 		port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
1689 	}
1690 out:
1691 	return port;
1692 }
1693 
1694 /**
1695  * xs_set_port - reset the port number in the remote endpoint address
1696  * @xprt: generic transport
1697  * @port: new port number
1698  *
1699  */
1700 static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
1701 {
1702 	dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
1703 
1704 	rpc_set_port(xs_addr(xprt), port);
1705 	xs_update_peer_port(xprt);
1706 }
1707 
1708 static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
1709 {
1710 	if (transport->srcport == 0 && transport->xprt.reuseport)
1711 		transport->srcport = xs_sock_getport(sock);
1712 }
1713 
1714 static int xs_get_srcport(struct sock_xprt *transport)
1715 {
1716 	int port = transport->srcport;
1717 
1718 	if (port == 0 && transport->xprt.resvport)
1719 		port = xs_get_random_port();
1720 	return port;
1721 }
1722 
1723 static unsigned short xs_sock_srcport(struct rpc_xprt *xprt)
1724 {
1725 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1726 	unsigned short ret = 0;
1727 	mutex_lock(&sock->recv_mutex);
1728 	if (sock->sock)
1729 		ret = xs_sock_getport(sock->sock);
1730 	mutex_unlock(&sock->recv_mutex);
1731 	return ret;
1732 }
1733 
1734 static int xs_sock_srcaddr(struct rpc_xprt *xprt, char *buf, size_t buflen)
1735 {
1736 	struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt);
1737 	union {
1738 		struct sockaddr sa;
1739 		struct sockaddr_storage st;
1740 	} saddr;
1741 	int ret = -ENOTCONN;
1742 
1743 	mutex_lock(&sock->recv_mutex);
1744 	if (sock->sock) {
1745 		ret = kernel_getsockname(sock->sock, &saddr.sa);
1746 		if (ret >= 0)
1747 			ret = snprintf(buf, buflen, "%pISc", &saddr.sa);
1748 	}
1749 	mutex_unlock(&sock->recv_mutex);
1750 	return ret;
1751 }
1752 
1753 static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
1754 {
1755 	if (transport->srcport != 0)
1756 		transport->srcport = 0;
1757 	if (!transport->xprt.resvport)
1758 		return 0;
1759 	if (port <= xprt_min_resvport || port > xprt_max_resvport)
1760 		return xprt_max_resvport;
1761 	return --port;
1762 }
1763 static int xs_bind(struct sock_xprt *transport, struct socket *sock)
1764 {
1765 	struct sockaddr_storage myaddr;
1766 	int err, nloop = 0;
1767 	int port = xs_get_srcport(transport);
1768 	unsigned short last;
1769 
1770 	/*
1771 	 * If we are asking for any ephemeral port (i.e. port == 0 &&
1772 	 * transport->xprt.resvport == 0), don't bind.  Let the local
1773 	 * port selection happen implicitly when the socket is used
1774 	 * (for example at connect time).
1775 	 *
1776 	 * This ensures that we can continue to establish TCP
1777 	 * connections even when all local ephemeral ports are already
1778 	 * a part of some TCP connection.  This makes no difference
1779 	 * for UDP sockets, but also doesn't harm them.
1780 	 *
1781 	 * If we're asking for any reserved port (i.e. port == 0 &&
1782 	 * transport->xprt.resvport == 1) xs_get_srcport above will
1783 	 * ensure that port is non-zero and we will bind as needed.
1784 	 */
1785 	if (port <= 0)
1786 		return port;
1787 
1788 	memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
1789 	do {
1790 		rpc_set_port((struct sockaddr *)&myaddr, port);
1791 		err = kernel_bind(sock, (struct sockaddr *)&myaddr,
1792 				transport->xprt.addrlen);
1793 		if (err == 0) {
1794 			if (transport->xprt.reuseport)
1795 				transport->srcport = port;
1796 			break;
1797 		}
1798 		last = port;
1799 		port = xs_next_srcport(transport, port);
1800 		if (port > last)
1801 			nloop++;
1802 	} while (err == -EADDRINUSE && nloop != 2);
1803 
1804 	if (myaddr.ss_family == AF_INET)
1805 		dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
1806 				&((struct sockaddr_in *)&myaddr)->sin_addr,
1807 				port, err ? "failed" : "ok", err);
1808 	else
1809 		dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
1810 				&((struct sockaddr_in6 *)&myaddr)->sin6_addr,
1811 				port, err ? "failed" : "ok", err);
1812 	return err;
1813 }
1814 
1815 /*
1816  * We don't support autobind on AF_LOCAL sockets
1817  */
1818 static void xs_local_rpcbind(struct rpc_task *task)
1819 {
1820 	xprt_set_bound(task->tk_xprt);
1821 }
1822 
1823 static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
1824 {
1825 }
1826 
1827 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1828 static struct lock_class_key xs_key[3];
1829 static struct lock_class_key xs_slock_key[3];
1830 
1831 static inline void xs_reclassify_socketu(struct socket *sock)
1832 {
1833 	struct sock *sk = sock->sk;
1834 
1835 	sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
1836 		&xs_slock_key[0], "sk_lock-AF_LOCAL-RPC", &xs_key[0]);
1837 }
1838 
1839 static inline void xs_reclassify_socket4(struct socket *sock)
1840 {
1841 	struct sock *sk = sock->sk;
1842 
1843 	sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
1844 		&xs_slock_key[1], "sk_lock-AF_INET-RPC", &xs_key[1]);
1845 }
1846 
1847 static inline void xs_reclassify_socket6(struct socket *sock)
1848 {
1849 	struct sock *sk = sock->sk;
1850 
1851 	sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
1852 		&xs_slock_key[2], "sk_lock-AF_INET6-RPC", &xs_key[2]);
1853 }
1854 
1855 static inline void xs_reclassify_socket(int family, struct socket *sock)
1856 {
1857 	if (WARN_ON_ONCE(!sock_allow_reclassification(sock->sk)))
1858 		return;
1859 
1860 	switch (family) {
1861 	case AF_LOCAL:
1862 		xs_reclassify_socketu(sock);
1863 		break;
1864 	case AF_INET:
1865 		xs_reclassify_socket4(sock);
1866 		break;
1867 	case AF_INET6:
1868 		xs_reclassify_socket6(sock);
1869 		break;
1870 	}
1871 }
1872 #else
1873 static inline void xs_reclassify_socket(int family, struct socket *sock)
1874 {
1875 }
1876 #endif
1877 
1878 static void xs_dummy_setup_socket(struct work_struct *work)
1879 {
1880 }
1881 
1882 static struct socket *xs_create_sock(struct rpc_xprt *xprt,
1883 		struct sock_xprt *transport, int family, int type,
1884 		int protocol, bool reuseport)
1885 {
1886 	struct file *filp;
1887 	struct socket *sock;
1888 	int err;
1889 
1890 	err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
1891 	if (err < 0) {
1892 		dprintk("RPC:       can't create %d transport socket (%d).\n",
1893 				protocol, -err);
1894 		goto out;
1895 	}
1896 	xs_reclassify_socket(family, sock);
1897 
1898 	if (reuseport)
1899 		sock_set_reuseport(sock->sk);
1900 
1901 	err = xs_bind(transport, sock);
1902 	if (err) {
1903 		sock_release(sock);
1904 		goto out;
1905 	}
1906 
1907 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1908 	if (IS_ERR(filp))
1909 		return ERR_CAST(filp);
1910 	transport->file = filp;
1911 
1912 	return sock;
1913 out:
1914 	return ERR_PTR(err);
1915 }
1916 
1917 static int xs_local_finish_connecting(struct rpc_xprt *xprt,
1918 				      struct socket *sock)
1919 {
1920 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
1921 									xprt);
1922 
1923 	if (!transport->inet) {
1924 		struct sock *sk = sock->sk;
1925 
1926 		lock_sock(sk);
1927 
1928 		xs_save_old_callbacks(transport, sk);
1929 
1930 		sk->sk_user_data = xprt;
1931 		sk->sk_data_ready = xs_data_ready;
1932 		sk->sk_write_space = xs_udp_write_space;
1933 		sk->sk_state_change = xs_local_state_change;
1934 		sk->sk_error_report = xs_error_report;
1935 		sk->sk_use_task_frag = false;
1936 
1937 		xprt_clear_connected(xprt);
1938 
1939 		/* Reset to new socket */
1940 		transport->sock = sock;
1941 		transport->inet = sk;
1942 
1943 		release_sock(sk);
1944 	}
1945 
1946 	xs_stream_start_connect(transport);
1947 
1948 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
1949 }
1950 
1951 /**
1952  * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
1953  * @transport: socket transport to connect
1954  */
1955 static int xs_local_setup_socket(struct sock_xprt *transport)
1956 {
1957 	struct rpc_xprt *xprt = &transport->xprt;
1958 	struct file *filp;
1959 	struct socket *sock;
1960 	int status;
1961 
1962 	status = __sock_create(xprt->xprt_net, AF_LOCAL,
1963 					SOCK_STREAM, 0, &sock, 1);
1964 	if (status < 0) {
1965 		dprintk("RPC:       can't create AF_LOCAL "
1966 			"transport socket (%d).\n", -status);
1967 		goto out;
1968 	}
1969 	xs_reclassify_socket(AF_LOCAL, sock);
1970 
1971 	filp = sock_alloc_file(sock, O_NONBLOCK, NULL);
1972 	if (IS_ERR(filp)) {
1973 		status = PTR_ERR(filp);
1974 		goto out;
1975 	}
1976 	transport->file = filp;
1977 
1978 	dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
1979 			xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1980 
1981 	status = xs_local_finish_connecting(xprt, sock);
1982 	trace_rpc_socket_connect(xprt, sock, status);
1983 	switch (status) {
1984 	case 0:
1985 		dprintk("RPC:       xprt %p connected to %s\n",
1986 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1987 		xprt->stat.connect_count++;
1988 		xprt->stat.connect_time += (long)jiffies -
1989 					   xprt->stat.connect_start;
1990 		xprt_set_connected(xprt);
1991 		break;
1992 	case -ENOBUFS:
1993 		break;
1994 	case -ENOENT:
1995 		dprintk("RPC:       xprt %p: socket %s does not exist\n",
1996 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
1997 		break;
1998 	case -ECONNREFUSED:
1999 		dprintk("RPC:       xprt %p: connection refused for %s\n",
2000 				xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
2001 		break;
2002 	default:
2003 		printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
2004 				__func__, -status,
2005 				xprt->address_strings[RPC_DISPLAY_ADDR]);
2006 	}
2007 
2008 out:
2009 	xprt_clear_connecting(xprt);
2010 	xprt_wake_pending_tasks(xprt, status);
2011 	return status;
2012 }
2013 
2014 static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2015 {
2016 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2017 	int ret;
2018 
2019 	if (transport->file)
2020 		goto force_disconnect;
2021 
2022 	if (RPC_IS_ASYNC(task)) {
2023 		/*
2024 		 * We want the AF_LOCAL connect to be resolved in the
2025 		 * filesystem namespace of the process making the rpc
2026 		 * call.  Thus we connect synchronously.
2027 		 *
2028 		 * If we want to support asynchronous AF_LOCAL calls,
2029 		 * we'll need to figure out how to pass a namespace to
2030 		 * connect.
2031 		 */
2032 		rpc_task_set_rpc_status(task, -ENOTCONN);
2033 		goto out_wake;
2034 	}
2035 	ret = xs_local_setup_socket(transport);
2036 	if (ret && !RPC_IS_SOFTCONN(task))
2037 		msleep_interruptible(15000);
2038 	return;
2039 force_disconnect:
2040 	xprt_force_disconnect(xprt);
2041 out_wake:
2042 	xprt_clear_connecting(xprt);
2043 	xprt_wake_pending_tasks(xprt, -ENOTCONN);
2044 }
2045 
2046 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2047 /*
2048  * Note that this should be called with XPRT_LOCKED held, or recv_mutex
2049  * held, or when we otherwise know that we have exclusive access to the
2050  * socket, to guard against races with xs_reset_transport.
2051  */
2052 static void xs_set_memalloc(struct rpc_xprt *xprt)
2053 {
2054 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
2055 			xprt);
2056 
2057 	/*
2058 	 * If there's no sock, then we have nothing to set. The
2059 	 * reconnecting process will get it for us.
2060 	 */
2061 	if (!transport->inet)
2062 		return;
2063 	if (atomic_read(&xprt->swapper))
2064 		sk_set_memalloc(transport->inet);
2065 }
2066 
2067 /**
2068  * xs_enable_swap - Tag this transport as being used for swap.
2069  * @xprt: transport to tag
2070  *
2071  * Take a reference to this transport on behalf of the rpc_clnt, and
2072  * optionally mark it for swapping if it wasn't already.
2073  */
2074 static int
2075 xs_enable_swap(struct rpc_xprt *xprt)
2076 {
2077 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2078 
2079 	mutex_lock(&xs->recv_mutex);
2080 	if (atomic_inc_return(&xprt->swapper) == 1 &&
2081 	    xs->inet)
2082 		sk_set_memalloc(xs->inet);
2083 	mutex_unlock(&xs->recv_mutex);
2084 	return 0;
2085 }
2086 
2087 /**
2088  * xs_disable_swap - Untag this transport as being used for swap.
2089  * @xprt: transport to tag
2090  *
2091  * Drop a "swapper" reference to this xprt on behalf of the rpc_clnt. If the
2092  * swapper refcount goes to 0, untag the socket as a memalloc socket.
2093  */
2094 static void
2095 xs_disable_swap(struct rpc_xprt *xprt)
2096 {
2097 	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);
2098 
2099 	mutex_lock(&xs->recv_mutex);
2100 	if (atomic_dec_and_test(&xprt->swapper) &&
2101 	    xs->inet)
2102 		sk_clear_memalloc(xs->inet);
2103 	mutex_unlock(&xs->recv_mutex);
2104 }
2105 #else
2106 static void xs_set_memalloc(struct rpc_xprt *xprt)
2107 {
2108 }
2109 
2110 static int
2111 xs_enable_swap(struct rpc_xprt *xprt)
2112 {
2113 	return -EINVAL;
2114 }
2115 
2116 static void
2117 xs_disable_swap(struct rpc_xprt *xprt)
2118 {
2119 }
2120 #endif
2121 
2122 static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2123 {
2124 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2125 
2126 	if (!transport->inet) {
2127 		struct sock *sk = sock->sk;
2128 
2129 		lock_sock(sk);
2130 
2131 		xs_save_old_callbacks(transport, sk);
2132 
2133 		sk->sk_user_data = xprt;
2134 		sk->sk_data_ready = xs_data_ready;
2135 		sk->sk_write_space = xs_udp_write_space;
2136 		sk->sk_use_task_frag = false;
2137 
2138 		xprt_set_connected(xprt);
2139 
2140 		/* Reset to new socket */
2141 		transport->sock = sock;
2142 		transport->inet = sk;
2143 
2144 		xs_set_memalloc(xprt);
2145 
2146 		release_sock(sk);
2147 	}
2148 	xs_udp_do_set_buffer_size(xprt);
2149 
2150 	xprt->stat.connect_start = jiffies;
2151 }
2152 
2153 static void xs_udp_setup_socket(struct work_struct *work)
2154 {
2155 	struct sock_xprt *transport =
2156 		container_of(work, struct sock_xprt, connect_worker.work);
2157 	struct rpc_xprt *xprt = &transport->xprt;
2158 	struct socket *sock;
2159 	int status = -EIO;
2160 	unsigned int pflags = current->flags;
2161 
2162 	if (atomic_read(&xprt->swapper))
2163 		current->flags |= PF_MEMALLOC;
2164 	sock = xs_create_sock(xprt, transport,
2165 			xs_addr(xprt)->sa_family, SOCK_DGRAM,
2166 			IPPROTO_UDP, false);
2167 	if (IS_ERR(sock))
2168 		goto out;
2169 
2170 	dprintk("RPC:       worker connecting xprt %p via %s to "
2171 				"%s (port %s)\n", xprt,
2172 			xprt->address_strings[RPC_DISPLAY_PROTO],
2173 			xprt->address_strings[RPC_DISPLAY_ADDR],
2174 			xprt->address_strings[RPC_DISPLAY_PORT]);
2175 
2176 	xs_udp_finish_connecting(xprt, sock);
2177 	trace_rpc_socket_connect(xprt, sock, 0);
2178 	status = 0;
2179 out:
2180 	xprt_clear_connecting(xprt);
2181 	xprt_unlock_connect(xprt, transport);
2182 	xprt_wake_pending_tasks(xprt, status);
2183 	current_restore_flags(pflags, PF_MEMALLOC);
2184 }
2185 
2186 /**
2187  * xs_tcp_shutdown - gracefully shut down a TCP socket
2188  * @xprt: transport
2189  *
2190  * Initiates a graceful shutdown of the TCP socket by calling the
2191  * equivalent of shutdown(SHUT_RDWR);
2192  */
2193 static void xs_tcp_shutdown(struct rpc_xprt *xprt)
2194 {
2195 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2196 	struct socket *sock = transport->sock;
2197 	int skst = transport->inet ? transport->inet->sk_state : TCP_CLOSE;
2198 
2199 	if (sock == NULL)
2200 		return;
2201 	if (!xprt->reuseport) {
2202 		xs_close(xprt);
2203 		return;
2204 	}
2205 	switch (skst) {
2206 	case TCP_FIN_WAIT1:
2207 	case TCP_FIN_WAIT2:
2208 	case TCP_LAST_ACK:
2209 		break;
2210 	case TCP_ESTABLISHED:
2211 	case TCP_CLOSE_WAIT:
2212 		kernel_sock_shutdown(sock, SHUT_RDWR);
2213 		trace_rpc_socket_shutdown(xprt, sock);
2214 		break;
2215 	default:
2216 		xs_reset_transport(transport);
2217 	}
2218 }
2219 
2220 static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
2221 		struct socket *sock)
2222 {
2223 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2224 	unsigned int keepidle;
2225 	unsigned int keepcnt;
2226 	unsigned int timeo;
2227 
2228 	spin_lock(&xprt->transport_lock);
2229 	keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
2230 	keepcnt = xprt->timeout->to_retries + 1;
2231 	timeo = jiffies_to_msecs(xprt->timeout->to_initval) *
2232 		(xprt->timeout->to_retries + 1);
2233 	clear_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2234 	spin_unlock(&xprt->transport_lock);
2235 
2236 	/* TCP Keepalive options */
2237 	sock_set_keepalive(sock->sk);
2238 	tcp_sock_set_keepidle(sock->sk, keepidle);
2239 	tcp_sock_set_keepintvl(sock->sk, keepidle);
2240 	tcp_sock_set_keepcnt(sock->sk, keepcnt);
2241 
2242 	/* TCP user timeout (see RFC5482) */
2243 	tcp_sock_set_user_timeout(sock->sk, timeo);
2244 }
2245 
2246 static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
2247 		unsigned long connect_timeout,
2248 		unsigned long reconnect_timeout)
2249 {
2250 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2251 	struct rpc_timeout to;
2252 	unsigned long initval;
2253 
2254 	spin_lock(&xprt->transport_lock);
2255 	if (reconnect_timeout < xprt->max_reconnect_timeout)
2256 		xprt->max_reconnect_timeout = reconnect_timeout;
2257 	if (connect_timeout < xprt->connect_timeout) {
2258 		memcpy(&to, xprt->timeout, sizeof(to));
2259 		initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
2260 		/* Arbitrary lower limit */
2261 		if (initval <  XS_TCP_INIT_REEST_TO << 1)
2262 			initval = XS_TCP_INIT_REEST_TO << 1;
2263 		to.to_initval = initval;
2264 		to.to_maxval = initval;
2265 		memcpy(&transport->tcp_timeout, &to,
2266 				sizeof(transport->tcp_timeout));
2267 		xprt->timeout = &transport->tcp_timeout;
2268 		xprt->connect_timeout = connect_timeout;
2269 	}
2270 	set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
2271 	spin_unlock(&xprt->transport_lock);
2272 }
2273 
2274 static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
2275 {
2276 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2277 
2278 	if (!transport->inet) {
2279 		struct sock *sk = sock->sk;
2280 
2281 		/* Avoid temporary address, they are bad for long-lived
2282 		 * connections such as NFS mounts.
2283 		 * RFC4941, section 3.6 suggests that:
2284 		 *    Individual applications, which have specific
2285 		 *    knowledge about the normal duration of connections,
2286 		 *    MAY override this as appropriate.
2287 		 */
2288 		if (xs_addr(xprt)->sa_family == PF_INET6) {
2289 			ip6_sock_set_addr_preferences(sk,
2290 				IPV6_PREFER_SRC_PUBLIC);
2291 		}
2292 
2293 		xs_tcp_set_socket_timeouts(xprt, sock);
2294 		tcp_sock_set_nodelay(sk);
2295 
2296 		lock_sock(sk);
2297 
2298 		xs_save_old_callbacks(transport, sk);
2299 
2300 		sk->sk_user_data = xprt;
2301 		sk->sk_data_ready = xs_data_ready;
2302 		sk->sk_state_change = xs_tcp_state_change;
2303 		sk->sk_write_space = xs_tcp_write_space;
2304 		sk->sk_error_report = xs_error_report;
2305 		sk->sk_use_task_frag = false;
2306 
2307 		/* socket options */
2308 		sock_reset_flag(sk, SOCK_LINGER);
2309 
2310 		xprt_clear_connected(xprt);
2311 
2312 		/* Reset to new socket */
2313 		transport->sock = sock;
2314 		transport->inet = sk;
2315 
2316 		release_sock(sk);
2317 	}
2318 
2319 	if (!xprt_bound(xprt))
2320 		return -ENOTCONN;
2321 
2322 	xs_set_memalloc(xprt);
2323 
2324 	xs_stream_start_connect(transport);
2325 
2326 	/* Tell the socket layer to start connecting... */
2327 	set_bit(XPRT_SOCK_CONNECTING, &transport->sock_state);
2328 	return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
2329 }
2330 
2331 /**
2332  * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
2333  * @work: queued work item
2334  *
2335  * Invoked by a work queue tasklet.
2336  */
2337 static void xs_tcp_setup_socket(struct work_struct *work)
2338 {
2339 	struct sock_xprt *transport =
2340 		container_of(work, struct sock_xprt, connect_worker.work);
2341 	struct socket *sock = transport->sock;
2342 	struct rpc_xprt *xprt = &transport->xprt;
2343 	int status;
2344 	unsigned int pflags = current->flags;
2345 
2346 	if (atomic_read(&xprt->swapper))
2347 		current->flags |= PF_MEMALLOC;
2348 
2349 	if (xprt_connected(xprt))
2350 		goto out;
2351 	if (test_and_clear_bit(XPRT_SOCK_CONNECT_SENT,
2352 			       &transport->sock_state) ||
2353 	    !sock) {
2354 		xs_reset_transport(transport);
2355 		sock = xs_create_sock(xprt, transport, xs_addr(xprt)->sa_family,
2356 				      SOCK_STREAM, IPPROTO_TCP, true);
2357 		if (IS_ERR(sock)) {
2358 			xprt_wake_pending_tasks(xprt, PTR_ERR(sock));
2359 			goto out;
2360 		}
2361 	}
2362 
2363 	dprintk("RPC:       worker connecting xprt %p via %s to "
2364 				"%s (port %s)\n", xprt,
2365 			xprt->address_strings[RPC_DISPLAY_PROTO],
2366 			xprt->address_strings[RPC_DISPLAY_ADDR],
2367 			xprt->address_strings[RPC_DISPLAY_PORT]);
2368 
2369 	status = xs_tcp_finish_connecting(xprt, sock);
2370 	trace_rpc_socket_connect(xprt, sock, status);
2371 	dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
2372 			xprt, -status, xprt_connected(xprt),
2373 			sock->sk->sk_state);
2374 	switch (status) {
2375 	case 0:
2376 	case -EINPROGRESS:
2377 		/* SYN_SENT! */
2378 		set_bit(XPRT_SOCK_CONNECT_SENT, &transport->sock_state);
2379 		if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
2380 			xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2381 		fallthrough;
2382 	case -EALREADY:
2383 		goto out_unlock;
2384 	case -EADDRNOTAVAIL:
2385 		/* Source port number is unavailable. Try a new one! */
2386 		transport->srcport = 0;
2387 		status = -EAGAIN;
2388 		break;
2389 	case -EINVAL:
2390 		/* Happens, for instance, if the user specified a link
2391 		 * local IPv6 address without a scope-id.
2392 		 */
2393 	case -ECONNREFUSED:
2394 	case -ECONNRESET:
2395 	case -ENETDOWN:
2396 	case -ENETUNREACH:
2397 	case -EHOSTUNREACH:
2398 	case -EADDRINUSE:
2399 	case -ENOBUFS:
2400 		break;
2401 	default:
2402 		printk("%s: connect returned unhandled error %d\n",
2403 			__func__, status);
2404 		status = -EAGAIN;
2405 	}
2406 
2407 	/* xs_tcp_force_close() wakes tasks with a fixed error code.
2408 	 * We need to wake them first to ensure the correct error code.
2409 	 */
2410 	xprt_wake_pending_tasks(xprt, status);
2411 	xs_tcp_force_close(xprt);
2412 out:
2413 	xprt_clear_connecting(xprt);
2414 out_unlock:
2415 	xprt_unlock_connect(xprt, transport);
2416 	current_restore_flags(pflags, PF_MEMALLOC);
2417 }
2418 
2419 /**
2420  * xs_connect - connect a socket to a remote endpoint
2421  * @xprt: pointer to transport structure
2422  * @task: address of RPC task that manages state of connect request
2423  *
2424  * TCP: If the remote end dropped the connection, delay reconnecting.
2425  *
2426  * UDP socket connects are synchronous, but we use a work queue anyway
2427  * to guarantee that even unprivileged user processes can set up a
2428  * socket on a privileged port.
2429  *
2430  * If a UDP socket connect fails, the delay behavior here prevents
2431  * retry floods (hard mounts).
2432  */
2433 static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
2434 {
2435 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2436 	unsigned long delay = 0;
2437 
2438 	WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
2439 
2440 	if (transport->sock != NULL) {
2441 		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
2442 			"seconds\n", xprt, xprt->reestablish_timeout / HZ);
2443 
2444 		delay = xprt_reconnect_delay(xprt);
2445 		xprt_reconnect_backoff(xprt, XS_TCP_INIT_REEST_TO);
2446 
2447 	} else
2448 		dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
2449 
2450 	queue_delayed_work(xprtiod_workqueue,
2451 			&transport->connect_worker,
2452 			delay);
2453 }
2454 
2455 static void xs_wake_disconnect(struct sock_xprt *transport)
2456 {
2457 	if (test_and_clear_bit(XPRT_SOCK_WAKE_DISCONNECT, &transport->sock_state))
2458 		xs_tcp_force_close(&transport->xprt);
2459 }
2460 
2461 static void xs_wake_write(struct sock_xprt *transport)
2462 {
2463 	if (test_and_clear_bit(XPRT_SOCK_WAKE_WRITE, &transport->sock_state))
2464 		xprt_write_space(&transport->xprt);
2465 }
2466 
2467 static void xs_wake_error(struct sock_xprt *transport)
2468 {
2469 	int sockerr;
2470 
2471 	if (!test_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2472 		return;
2473 	mutex_lock(&transport->recv_mutex);
2474 	if (transport->sock == NULL)
2475 		goto out;
2476 	if (!test_and_clear_bit(XPRT_SOCK_WAKE_ERROR, &transport->sock_state))
2477 		goto out;
2478 	sockerr = xchg(&transport->xprt_err, 0);
2479 	if (sockerr < 0)
2480 		xprt_wake_pending_tasks(&transport->xprt, sockerr);
2481 out:
2482 	mutex_unlock(&transport->recv_mutex);
2483 }
2484 
2485 static void xs_wake_pending(struct sock_xprt *transport)
2486 {
2487 	if (test_and_clear_bit(XPRT_SOCK_WAKE_PENDING, &transport->sock_state))
2488 		xprt_wake_pending_tasks(&transport->xprt, -EAGAIN);
2489 }
2490 
2491 static void xs_error_handle(struct work_struct *work)
2492 {
2493 	struct sock_xprt *transport = container_of(work,
2494 			struct sock_xprt, error_worker);
2495 
2496 	xs_wake_disconnect(transport);
2497 	xs_wake_write(transport);
2498 	xs_wake_error(transport);
2499 	xs_wake_pending(transport);
2500 }
2501 
2502 /**
2503  * xs_local_print_stats - display AF_LOCAL socket-specific stats
2504  * @xprt: rpc_xprt struct containing statistics
2505  * @seq: output file
2506  *
2507  */
2508 static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2509 {
2510 	long idle_time = 0;
2511 
2512 	if (xprt_connected(xprt))
2513 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2514 
2515 	seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
2516 			"%llu %llu %lu %llu %llu\n",
2517 			xprt->stat.bind_count,
2518 			xprt->stat.connect_count,
2519 			xprt->stat.connect_time / HZ,
2520 			idle_time,
2521 			xprt->stat.sends,
2522 			xprt->stat.recvs,
2523 			xprt->stat.bad_xids,
2524 			xprt->stat.req_u,
2525 			xprt->stat.bklog_u,
2526 			xprt->stat.max_slots,
2527 			xprt->stat.sending_u,
2528 			xprt->stat.pending_u);
2529 }
2530 
2531 /**
2532  * xs_udp_print_stats - display UDP socket-specific stats
2533  * @xprt: rpc_xprt struct containing statistics
2534  * @seq: output file
2535  *
2536  */
2537 static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2538 {
2539 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2540 
2541 	seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
2542 			"%lu %llu %llu\n",
2543 			transport->srcport,
2544 			xprt->stat.bind_count,
2545 			xprt->stat.sends,
2546 			xprt->stat.recvs,
2547 			xprt->stat.bad_xids,
2548 			xprt->stat.req_u,
2549 			xprt->stat.bklog_u,
2550 			xprt->stat.max_slots,
2551 			xprt->stat.sending_u,
2552 			xprt->stat.pending_u);
2553 }
2554 
2555 /**
2556  * xs_tcp_print_stats - display TCP socket-specific stats
2557  * @xprt: rpc_xprt struct containing statistics
2558  * @seq: output file
2559  *
2560  */
2561 static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
2562 {
2563 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
2564 	long idle_time = 0;
2565 
2566 	if (xprt_connected(xprt))
2567 		idle_time = (long)(jiffies - xprt->last_used) / HZ;
2568 
2569 	seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
2570 			"%llu %llu %lu %llu %llu\n",
2571 			transport->srcport,
2572 			xprt->stat.bind_count,
2573 			xprt->stat.connect_count,
2574 			xprt->stat.connect_time / HZ,
2575 			idle_time,
2576 			xprt->stat.sends,
2577 			xprt->stat.recvs,
2578 			xprt->stat.bad_xids,
2579 			xprt->stat.req_u,
2580 			xprt->stat.bklog_u,
2581 			xprt->stat.max_slots,
2582 			xprt->stat.sending_u,
2583 			xprt->stat.pending_u);
2584 }
2585 
2586 /*
2587  * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
2588  * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
2589  * to use the server side send routines.
2590  */
2591 static int bc_malloc(struct rpc_task *task)
2592 {
2593 	struct rpc_rqst *rqst = task->tk_rqstp;
2594 	size_t size = rqst->rq_callsize;
2595 	struct page *page;
2596 	struct rpc_buffer *buf;
2597 
2598 	if (size > PAGE_SIZE - sizeof(struct rpc_buffer)) {
2599 		WARN_ONCE(1, "xprtsock: large bc buffer request (size %zu)\n",
2600 			  size);
2601 		return -EINVAL;
2602 	}
2603 
2604 	page = alloc_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
2605 	if (!page)
2606 		return -ENOMEM;
2607 
2608 	buf = page_address(page);
2609 	buf->len = PAGE_SIZE;
2610 
2611 	rqst->rq_buffer = buf->data;
2612 	rqst->rq_rbuffer = (char *)rqst->rq_buffer + rqst->rq_callsize;
2613 	return 0;
2614 }
2615 
2616 /*
2617  * Free the space allocated in the bc_alloc routine
2618  */
2619 static void bc_free(struct rpc_task *task)
2620 {
2621 	void *buffer = task->tk_rqstp->rq_buffer;
2622 	struct rpc_buffer *buf;
2623 
2624 	buf = container_of(buffer, struct rpc_buffer, data);
2625 	free_page((unsigned long)buf);
2626 }
2627 
2628 static int bc_sendto(struct rpc_rqst *req)
2629 {
2630 	struct xdr_buf *xdr = &req->rq_snd_buf;
2631 	struct sock_xprt *transport =
2632 			container_of(req->rq_xprt, struct sock_xprt, xprt);
2633 	struct msghdr msg = {
2634 		.msg_flags	= 0,
2635 	};
2636 	rpc_fraghdr marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT |
2637 					 (u32)xdr->len);
2638 	unsigned int sent = 0;
2639 	int err;
2640 
2641 	req->rq_xtime = ktime_get();
2642 	err = xdr_alloc_bvec(xdr, rpc_task_gfp_mask());
2643 	if (err < 0)
2644 		return err;
2645 	err = xprt_sock_sendmsg(transport->sock, &msg, xdr, 0, marker, &sent);
2646 	xdr_free_bvec(xdr);
2647 	if (err < 0 || sent != (xdr->len + sizeof(marker)))
2648 		return -EAGAIN;
2649 	return sent;
2650 }
2651 
2652 /**
2653  * bc_send_request - Send a backchannel Call on a TCP socket
2654  * @req: rpc_rqst containing Call message to be sent
2655  *
2656  * xpt_mutex ensures @rqstp's whole message is written to the socket
2657  * without interruption.
2658  *
2659  * Return values:
2660  *   %0 if the message was sent successfully
2661  *   %ENOTCONN if the message was not sent
2662  */
2663 static int bc_send_request(struct rpc_rqst *req)
2664 {
2665 	struct svc_xprt	*xprt;
2666 	int len;
2667 
2668 	/*
2669 	 * Get the server socket associated with this callback xprt
2670 	 */
2671 	xprt = req->rq_xprt->bc_xprt;
2672 
2673 	/*
2674 	 * Grab the mutex to serialize data as the connection is shared
2675 	 * with the fore channel
2676 	 */
2677 	mutex_lock(&xprt->xpt_mutex);
2678 	if (test_bit(XPT_DEAD, &xprt->xpt_flags))
2679 		len = -ENOTCONN;
2680 	else
2681 		len = bc_sendto(req);
2682 	mutex_unlock(&xprt->xpt_mutex);
2683 
2684 	if (len > 0)
2685 		len = 0;
2686 
2687 	return len;
2688 }
2689 
2690 /*
2691  * The close routine. Since this is client initiated, we do nothing
2692  */
2693 
2694 static void bc_close(struct rpc_xprt *xprt)
2695 {
2696 	xprt_disconnect_done(xprt);
2697 }
2698 
2699 /*
2700  * The xprt destroy routine. Again, because this connection is client
2701  * initiated, we do nothing
2702  */
2703 
2704 static void bc_destroy(struct rpc_xprt *xprt)
2705 {
2706 	dprintk("RPC:       bc_destroy xprt %p\n", xprt);
2707 
2708 	xs_xprt_free(xprt);
2709 	module_put(THIS_MODULE);
2710 }
2711 
2712 static const struct rpc_xprt_ops xs_local_ops = {
2713 	.reserve_xprt		= xprt_reserve_xprt,
2714 	.release_xprt		= xprt_release_xprt,
2715 	.alloc_slot		= xprt_alloc_slot,
2716 	.free_slot		= xprt_free_slot,
2717 	.rpcbind		= xs_local_rpcbind,
2718 	.set_port		= xs_local_set_port,
2719 	.connect		= xs_local_connect,
2720 	.buf_alloc		= rpc_malloc,
2721 	.buf_free		= rpc_free,
2722 	.prepare_request	= xs_stream_prepare_request,
2723 	.send_request		= xs_local_send_request,
2724 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2725 	.close			= xs_close,
2726 	.destroy		= xs_destroy,
2727 	.print_stats		= xs_local_print_stats,
2728 	.enable_swap		= xs_enable_swap,
2729 	.disable_swap		= xs_disable_swap,
2730 };
2731 
2732 static const struct rpc_xprt_ops xs_udp_ops = {
2733 	.set_buffer_size	= xs_udp_set_buffer_size,
2734 	.reserve_xprt		= xprt_reserve_xprt_cong,
2735 	.release_xprt		= xprt_release_xprt_cong,
2736 	.alloc_slot		= xprt_alloc_slot,
2737 	.free_slot		= xprt_free_slot,
2738 	.rpcbind		= rpcb_getport_async,
2739 	.set_port		= xs_set_port,
2740 	.connect		= xs_connect,
2741 	.get_srcaddr		= xs_sock_srcaddr,
2742 	.get_srcport		= xs_sock_srcport,
2743 	.buf_alloc		= rpc_malloc,
2744 	.buf_free		= rpc_free,
2745 	.send_request		= xs_udp_send_request,
2746 	.wait_for_reply_request	= xprt_wait_for_reply_request_rtt,
2747 	.timer			= xs_udp_timer,
2748 	.release_request	= xprt_release_rqst_cong,
2749 	.close			= xs_close,
2750 	.destroy		= xs_destroy,
2751 	.print_stats		= xs_udp_print_stats,
2752 	.enable_swap		= xs_enable_swap,
2753 	.disable_swap		= xs_disable_swap,
2754 	.inject_disconnect	= xs_inject_disconnect,
2755 };
2756 
2757 static const struct rpc_xprt_ops xs_tcp_ops = {
2758 	.reserve_xprt		= xprt_reserve_xprt,
2759 	.release_xprt		= xprt_release_xprt,
2760 	.alloc_slot		= xprt_alloc_slot,
2761 	.free_slot		= xprt_free_slot,
2762 	.rpcbind		= rpcb_getport_async,
2763 	.set_port		= xs_set_port,
2764 	.connect		= xs_connect,
2765 	.get_srcaddr		= xs_sock_srcaddr,
2766 	.get_srcport		= xs_sock_srcport,
2767 	.buf_alloc		= rpc_malloc,
2768 	.buf_free		= rpc_free,
2769 	.prepare_request	= xs_stream_prepare_request,
2770 	.send_request		= xs_tcp_send_request,
2771 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2772 	.close			= xs_tcp_shutdown,
2773 	.destroy		= xs_destroy,
2774 	.set_connect_timeout	= xs_tcp_set_connect_timeout,
2775 	.print_stats		= xs_tcp_print_stats,
2776 	.enable_swap		= xs_enable_swap,
2777 	.disable_swap		= xs_disable_swap,
2778 	.inject_disconnect	= xs_inject_disconnect,
2779 #ifdef CONFIG_SUNRPC_BACKCHANNEL
2780 	.bc_setup		= xprt_setup_bc,
2781 	.bc_maxpayload		= xs_tcp_bc_maxpayload,
2782 	.bc_num_slots		= xprt_bc_max_slots,
2783 	.bc_free_rqst		= xprt_free_bc_rqst,
2784 	.bc_destroy		= xprt_destroy_bc,
2785 #endif
2786 };
2787 
2788 /*
2789  * The rpc_xprt_ops for the server backchannel
2790  */
2791 
2792 static const struct rpc_xprt_ops bc_tcp_ops = {
2793 	.reserve_xprt		= xprt_reserve_xprt,
2794 	.release_xprt		= xprt_release_xprt,
2795 	.alloc_slot		= xprt_alloc_slot,
2796 	.free_slot		= xprt_free_slot,
2797 	.buf_alloc		= bc_malloc,
2798 	.buf_free		= bc_free,
2799 	.send_request		= bc_send_request,
2800 	.wait_for_reply_request	= xprt_wait_for_reply_request_def,
2801 	.close			= bc_close,
2802 	.destroy		= bc_destroy,
2803 	.print_stats		= xs_tcp_print_stats,
2804 	.enable_swap		= xs_enable_swap,
2805 	.disable_swap		= xs_disable_swap,
2806 	.inject_disconnect	= xs_inject_disconnect,
2807 };
2808 
2809 static int xs_init_anyaddr(const int family, struct sockaddr *sap)
2810 {
2811 	static const struct sockaddr_in sin = {
2812 		.sin_family		= AF_INET,
2813 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2814 	};
2815 	static const struct sockaddr_in6 sin6 = {
2816 		.sin6_family		= AF_INET6,
2817 		.sin6_addr		= IN6ADDR_ANY_INIT,
2818 	};
2819 
2820 	switch (family) {
2821 	case AF_LOCAL:
2822 		break;
2823 	case AF_INET:
2824 		memcpy(sap, &sin, sizeof(sin));
2825 		break;
2826 	case AF_INET6:
2827 		memcpy(sap, &sin6, sizeof(sin6));
2828 		break;
2829 	default:
2830 		dprintk("RPC:       %s: Bad address family\n", __func__);
2831 		return -EAFNOSUPPORT;
2832 	}
2833 	return 0;
2834 }
2835 
2836 static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
2837 				      unsigned int slot_table_size,
2838 				      unsigned int max_slot_table_size)
2839 {
2840 	struct rpc_xprt *xprt;
2841 	struct sock_xprt *new;
2842 
2843 	if (args->addrlen > sizeof(xprt->addr)) {
2844 		dprintk("RPC:       xs_setup_xprt: address too large\n");
2845 		return ERR_PTR(-EBADF);
2846 	}
2847 
2848 	xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
2849 			max_slot_table_size);
2850 	if (xprt == NULL) {
2851 		dprintk("RPC:       xs_setup_xprt: couldn't allocate "
2852 				"rpc_xprt\n");
2853 		return ERR_PTR(-ENOMEM);
2854 	}
2855 
2856 	new = container_of(xprt, struct sock_xprt, xprt);
2857 	mutex_init(&new->recv_mutex);
2858 	memcpy(&xprt->addr, args->dstaddr, args->addrlen);
2859 	xprt->addrlen = args->addrlen;
2860 	if (args->srcaddr)
2861 		memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
2862 	else {
2863 		int err;
2864 		err = xs_init_anyaddr(args->dstaddr->sa_family,
2865 					(struct sockaddr *)&new->srcaddr);
2866 		if (err != 0) {
2867 			xprt_free(xprt);
2868 			return ERR_PTR(err);
2869 		}
2870 	}
2871 
2872 	return xprt;
2873 }
2874 
2875 static const struct rpc_timeout xs_local_default_timeout = {
2876 	.to_initval = 10 * HZ,
2877 	.to_maxval = 10 * HZ,
2878 	.to_retries = 2,
2879 };
2880 
2881 /**
2882  * xs_setup_local - Set up transport to use an AF_LOCAL socket
2883  * @args: rpc transport creation arguments
2884  *
2885  * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
2886  */
2887 static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
2888 {
2889 	struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
2890 	struct sock_xprt *transport;
2891 	struct rpc_xprt *xprt;
2892 	struct rpc_xprt *ret;
2893 
2894 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
2895 			xprt_max_tcp_slot_table_entries);
2896 	if (IS_ERR(xprt))
2897 		return xprt;
2898 	transport = container_of(xprt, struct sock_xprt, xprt);
2899 
2900 	xprt->prot = 0;
2901 	xprt->xprt_class = &xs_local_transport;
2902 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
2903 
2904 	xprt->bind_timeout = XS_BIND_TO;
2905 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
2906 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2907 
2908 	xprt->ops = &xs_local_ops;
2909 	xprt->timeout = &xs_local_default_timeout;
2910 
2911 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
2912 	INIT_WORK(&transport->error_worker, xs_error_handle);
2913 	INIT_DELAYED_WORK(&transport->connect_worker, xs_dummy_setup_socket);
2914 
2915 	switch (sun->sun_family) {
2916 	case AF_LOCAL:
2917 		if (sun->sun_path[0] != '/' && sun->sun_path[0] != '\0') {
2918 			dprintk("RPC:       bad AF_LOCAL address: %s\n",
2919 					sun->sun_path);
2920 			ret = ERR_PTR(-EINVAL);
2921 			goto out_err;
2922 		}
2923 		xprt_set_bound(xprt);
2924 		xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
2925 		break;
2926 	default:
2927 		ret = ERR_PTR(-EAFNOSUPPORT);
2928 		goto out_err;
2929 	}
2930 
2931 	dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
2932 			xprt->address_strings[RPC_DISPLAY_ADDR]);
2933 
2934 	if (try_module_get(THIS_MODULE))
2935 		return xprt;
2936 	ret = ERR_PTR(-EINVAL);
2937 out_err:
2938 	xs_xprt_free(xprt);
2939 	return ret;
2940 }
2941 
2942 static const struct rpc_timeout xs_udp_default_timeout = {
2943 	.to_initval = 5 * HZ,
2944 	.to_maxval = 30 * HZ,
2945 	.to_increment = 5 * HZ,
2946 	.to_retries = 5,
2947 };
2948 
2949 /**
2950  * xs_setup_udp - Set up transport to use a UDP socket
2951  * @args: rpc transport creation arguments
2952  *
2953  */
2954 static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
2955 {
2956 	struct sockaddr *addr = args->dstaddr;
2957 	struct rpc_xprt *xprt;
2958 	struct sock_xprt *transport;
2959 	struct rpc_xprt *ret;
2960 
2961 	xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
2962 			xprt_udp_slot_table_entries);
2963 	if (IS_ERR(xprt))
2964 		return xprt;
2965 	transport = container_of(xprt, struct sock_xprt, xprt);
2966 
2967 	xprt->prot = IPPROTO_UDP;
2968 	xprt->xprt_class = &xs_udp_transport;
2969 	/* XXX: header size can vary due to auth type, IPv6, etc. */
2970 	xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
2971 
2972 	xprt->bind_timeout = XS_BIND_TO;
2973 	xprt->reestablish_timeout = XS_UDP_REEST_TO;
2974 	xprt->idle_timeout = XS_IDLE_DISC_TO;
2975 
2976 	xprt->ops = &xs_udp_ops;
2977 
2978 	xprt->timeout = &xs_udp_default_timeout;
2979 
2980 	INIT_WORK(&transport->recv_worker, xs_udp_data_receive_workfn);
2981 	INIT_WORK(&transport->error_worker, xs_error_handle);
2982 	INIT_DELAYED_WORK(&transport->connect_worker, xs_udp_setup_socket);
2983 
2984 	switch (addr->sa_family) {
2985 	case AF_INET:
2986 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
2987 			xprt_set_bound(xprt);
2988 
2989 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
2990 		break;
2991 	case AF_INET6:
2992 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
2993 			xprt_set_bound(xprt);
2994 
2995 		xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
2996 		break;
2997 	default:
2998 		ret = ERR_PTR(-EAFNOSUPPORT);
2999 		goto out_err;
3000 	}
3001 
3002 	if (xprt_bound(xprt))
3003 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3004 				xprt->address_strings[RPC_DISPLAY_ADDR],
3005 				xprt->address_strings[RPC_DISPLAY_PORT],
3006 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3007 	else
3008 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3009 				xprt->address_strings[RPC_DISPLAY_ADDR],
3010 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3011 
3012 	if (try_module_get(THIS_MODULE))
3013 		return xprt;
3014 	ret = ERR_PTR(-EINVAL);
3015 out_err:
3016 	xs_xprt_free(xprt);
3017 	return ret;
3018 }
3019 
3020 static const struct rpc_timeout xs_tcp_default_timeout = {
3021 	.to_initval = 60 * HZ,
3022 	.to_maxval = 60 * HZ,
3023 	.to_retries = 2,
3024 };
3025 
3026 /**
3027  * xs_setup_tcp - Set up transport to use a TCP socket
3028  * @args: rpc transport creation arguments
3029  *
3030  */
3031 static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
3032 {
3033 	struct sockaddr *addr = args->dstaddr;
3034 	struct rpc_xprt *xprt;
3035 	struct sock_xprt *transport;
3036 	struct rpc_xprt *ret;
3037 	unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
3038 
3039 	if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
3040 		max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
3041 
3042 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3043 			max_slot_table_size);
3044 	if (IS_ERR(xprt))
3045 		return xprt;
3046 	transport = container_of(xprt, struct sock_xprt, xprt);
3047 
3048 	xprt->prot = IPPROTO_TCP;
3049 	xprt->xprt_class = &xs_tcp_transport;
3050 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3051 
3052 	xprt->bind_timeout = XS_BIND_TO;
3053 	xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
3054 	xprt->idle_timeout = XS_IDLE_DISC_TO;
3055 
3056 	xprt->ops = &xs_tcp_ops;
3057 	xprt->timeout = &xs_tcp_default_timeout;
3058 
3059 	xprt->max_reconnect_timeout = xprt->timeout->to_maxval;
3060 	xprt->connect_timeout = xprt->timeout->to_initval *
3061 		(xprt->timeout->to_retries + 1);
3062 
3063 	INIT_WORK(&transport->recv_worker, xs_stream_data_receive_workfn);
3064 	INIT_WORK(&transport->error_worker, xs_error_handle);
3065 	INIT_DELAYED_WORK(&transport->connect_worker, xs_tcp_setup_socket);
3066 
3067 	switch (addr->sa_family) {
3068 	case AF_INET:
3069 		if (((struct sockaddr_in *)addr)->sin_port != htons(0))
3070 			xprt_set_bound(xprt);
3071 
3072 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
3073 		break;
3074 	case AF_INET6:
3075 		if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
3076 			xprt_set_bound(xprt);
3077 
3078 		xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
3079 		break;
3080 	default:
3081 		ret = ERR_PTR(-EAFNOSUPPORT);
3082 		goto out_err;
3083 	}
3084 
3085 	if (xprt_bound(xprt))
3086 		dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3087 				xprt->address_strings[RPC_DISPLAY_ADDR],
3088 				xprt->address_strings[RPC_DISPLAY_PORT],
3089 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3090 	else
3091 		dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
3092 				xprt->address_strings[RPC_DISPLAY_ADDR],
3093 				xprt->address_strings[RPC_DISPLAY_PROTO]);
3094 
3095 	if (try_module_get(THIS_MODULE))
3096 		return xprt;
3097 	ret = ERR_PTR(-EINVAL);
3098 out_err:
3099 	xs_xprt_free(xprt);
3100 	return ret;
3101 }
3102 
3103 /**
3104  * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
3105  * @args: rpc transport creation arguments
3106  *
3107  */
3108 static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
3109 {
3110 	struct sockaddr *addr = args->dstaddr;
3111 	struct rpc_xprt *xprt;
3112 	struct sock_xprt *transport;
3113 	struct svc_sock *bc_sock;
3114 	struct rpc_xprt *ret;
3115 
3116 	xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
3117 			xprt_tcp_slot_table_entries);
3118 	if (IS_ERR(xprt))
3119 		return xprt;
3120 	transport = container_of(xprt, struct sock_xprt, xprt);
3121 
3122 	xprt->prot = IPPROTO_TCP;
3123 	xprt->xprt_class = &xs_bc_tcp_transport;
3124 	xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
3125 	xprt->timeout = &xs_tcp_default_timeout;
3126 
3127 	/* backchannel */
3128 	xprt_set_bound(xprt);
3129 	xprt->bind_timeout = 0;
3130 	xprt->reestablish_timeout = 0;
3131 	xprt->idle_timeout = 0;
3132 
3133 	xprt->ops = &bc_tcp_ops;
3134 
3135 	switch (addr->sa_family) {
3136 	case AF_INET:
3137 		xs_format_peer_addresses(xprt, "tcp",
3138 					 RPCBIND_NETID_TCP);
3139 		break;
3140 	case AF_INET6:
3141 		xs_format_peer_addresses(xprt, "tcp",
3142 				   RPCBIND_NETID_TCP6);
3143 		break;
3144 	default:
3145 		ret = ERR_PTR(-EAFNOSUPPORT);
3146 		goto out_err;
3147 	}
3148 
3149 	dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
3150 			xprt->address_strings[RPC_DISPLAY_ADDR],
3151 			xprt->address_strings[RPC_DISPLAY_PORT],
3152 			xprt->address_strings[RPC_DISPLAY_PROTO]);
3153 
3154 	/*
3155 	 * Once we've associated a backchannel xprt with a connection,
3156 	 * we want to keep it around as long as the connection lasts,
3157 	 * in case we need to start using it for a backchannel again;
3158 	 * this reference won't be dropped until bc_xprt is destroyed.
3159 	 */
3160 	xprt_get(xprt);
3161 	args->bc_xprt->xpt_bc_xprt = xprt;
3162 	xprt->bc_xprt = args->bc_xprt;
3163 	bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
3164 	transport->sock = bc_sock->sk_sock;
3165 	transport->inet = bc_sock->sk_sk;
3166 
3167 	/*
3168 	 * Since we don't want connections for the backchannel, we set
3169 	 * the xprt status to connected
3170 	 */
3171 	xprt_set_connected(xprt);
3172 
3173 	if (try_module_get(THIS_MODULE))
3174 		return xprt;
3175 
3176 	args->bc_xprt->xpt_bc_xprt = NULL;
3177 	args->bc_xprt->xpt_bc_xps = NULL;
3178 	xprt_put(xprt);
3179 	ret = ERR_PTR(-EINVAL);
3180 out_err:
3181 	xs_xprt_free(xprt);
3182 	return ret;
3183 }
3184 
3185 static struct xprt_class	xs_local_transport = {
3186 	.list		= LIST_HEAD_INIT(xs_local_transport.list),
3187 	.name		= "named UNIX socket",
3188 	.owner		= THIS_MODULE,
3189 	.ident		= XPRT_TRANSPORT_LOCAL,
3190 	.setup		= xs_setup_local,
3191 	.netid		= { "" },
3192 };
3193 
3194 static struct xprt_class	xs_udp_transport = {
3195 	.list		= LIST_HEAD_INIT(xs_udp_transport.list),
3196 	.name		= "udp",
3197 	.owner		= THIS_MODULE,
3198 	.ident		= XPRT_TRANSPORT_UDP,
3199 	.setup		= xs_setup_udp,
3200 	.netid		= { "udp", "udp6", "" },
3201 };
3202 
3203 static struct xprt_class	xs_tcp_transport = {
3204 	.list		= LIST_HEAD_INIT(xs_tcp_transport.list),
3205 	.name		= "tcp",
3206 	.owner		= THIS_MODULE,
3207 	.ident		= XPRT_TRANSPORT_TCP,
3208 	.setup		= xs_setup_tcp,
3209 	.netid		= { "tcp", "tcp6", "" },
3210 };
3211 
3212 static struct xprt_class	xs_bc_tcp_transport = {
3213 	.list		= LIST_HEAD_INIT(xs_bc_tcp_transport.list),
3214 	.name		= "tcp NFSv4.1 backchannel",
3215 	.owner		= THIS_MODULE,
3216 	.ident		= XPRT_TRANSPORT_BC_TCP,
3217 	.setup		= xs_setup_bc_tcp,
3218 	.netid		= { "" },
3219 };
3220 
3221 /**
3222  * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
3223  *
3224  */
3225 int init_socket_xprt(void)
3226 {
3227 	if (!sunrpc_table_header)
3228 		sunrpc_table_header = register_sysctl("sunrpc", xs_tunables_table);
3229 
3230 	xprt_register_transport(&xs_local_transport);
3231 	xprt_register_transport(&xs_udp_transport);
3232 	xprt_register_transport(&xs_tcp_transport);
3233 	xprt_register_transport(&xs_bc_tcp_transport);
3234 
3235 	return 0;
3236 }
3237 
3238 /**
3239  * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
3240  *
3241  */
3242 void cleanup_socket_xprt(void)
3243 {
3244 	if (sunrpc_table_header) {
3245 		unregister_sysctl_table(sunrpc_table_header);
3246 		sunrpc_table_header = NULL;
3247 	}
3248 
3249 	xprt_unregister_transport(&xs_local_transport);
3250 	xprt_unregister_transport(&xs_udp_transport);
3251 	xprt_unregister_transport(&xs_tcp_transport);
3252 	xprt_unregister_transport(&xs_bc_tcp_transport);
3253 }
3254 
3255 static int param_set_portnr(const char *val, const struct kernel_param *kp)
3256 {
3257 	return param_set_uint_minmax(val, kp,
3258 			RPC_MIN_RESVPORT,
3259 			RPC_MAX_RESVPORT);
3260 }
3261 
3262 static const struct kernel_param_ops param_ops_portnr = {
3263 	.set = param_set_portnr,
3264 	.get = param_get_uint,
3265 };
3266 
3267 #define param_check_portnr(name, p) \
3268 	__param_check(name, p, unsigned int);
3269 
3270 module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
3271 module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
3272 
3273 static int param_set_slot_table_size(const char *val,
3274 				     const struct kernel_param *kp)
3275 {
3276 	return param_set_uint_minmax(val, kp,
3277 			RPC_MIN_SLOT_TABLE,
3278 			RPC_MAX_SLOT_TABLE);
3279 }
3280 
3281 static const struct kernel_param_ops param_ops_slot_table_size = {
3282 	.set = param_set_slot_table_size,
3283 	.get = param_get_uint,
3284 };
3285 
3286 #define param_check_slot_table_size(name, p) \
3287 	__param_check(name, p, unsigned int);
3288 
3289 static int param_set_max_slot_table_size(const char *val,
3290 				     const struct kernel_param *kp)
3291 {
3292 	return param_set_uint_minmax(val, kp,
3293 			RPC_MIN_SLOT_TABLE,
3294 			RPC_MAX_SLOT_TABLE_LIMIT);
3295 }
3296 
3297 static const struct kernel_param_ops param_ops_max_slot_table_size = {
3298 	.set = param_set_max_slot_table_size,
3299 	.get = param_get_uint,
3300 };
3301 
3302 #define param_check_max_slot_table_size(name, p) \
3303 	__param_check(name, p, unsigned int);
3304 
3305 module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
3306 		   slot_table_size, 0644);
3307 module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
3308 		   max_slot_table_size, 0644);
3309 module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
3310 		   slot_table_size, 0644);
3311