xref: /linux/net/sunrpc/svcsock.c (revision c33a605dd6f36618f9f658e71c09fcdcb44fc500)
1 /*
2  * linux/net/sunrpc/svcsock.c
3  *
4  * These are the RPC server socket internals.
5  *
6  * The server scheduling algorithm does not always distribute the load
7  * evenly when servicing a single client. May need to modify the
8  * svc_xprt_enqueue procedure...
9  *
10  * TCP support is largely untested and may be a little slow. The problem
11  * is that we currently do two separate recvfrom's, one for the 4-byte
12  * record length, and the second for the actual record. This could possibly
13  * be improved by always reading a minimum size of around 100 bytes and
14  * tucking any superfluous bytes away in a temporary store. Still, that
15  * leaves write requests out in the rain. An alternative may be to peek at
16  * the first skb in the queue, and if it matches the next TCP sequence
17  * number, to extract the record marker. Yuck.
18  *
19  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/sched.h>
24 #include <linux/module.h>
25 #include <linux/errno.h>
26 #include <linux/fcntl.h>
27 #include <linux/net.h>
28 #include <linux/in.h>
29 #include <linux/inet.h>
30 #include <linux/udp.h>
31 #include <linux/tcp.h>
32 #include <linux/unistd.h>
33 #include <linux/slab.h>
34 #include <linux/netdevice.h>
35 #include <linux/skbuff.h>
36 #include <linux/file.h>
37 #include <linux/freezer.h>
38 #include <net/sock.h>
39 #include <net/checksum.h>
40 #include <net/ip.h>
41 #include <net/ipv6.h>
42 #include <net/tcp.h>
43 #include <net/tcp_states.h>
44 #include <asm/uaccess.h>
45 #include <asm/ioctls.h>
46 #include <trace/events/skb.h>
47 
48 #include <linux/sunrpc/types.h>
49 #include <linux/sunrpc/clnt.h>
50 #include <linux/sunrpc/xdr.h>
51 #include <linux/sunrpc/msg_prot.h>
52 #include <linux/sunrpc/svcsock.h>
53 #include <linux/sunrpc/stats.h>
54 #include <linux/sunrpc/xprt.h>
55 
56 #include "sunrpc.h"
57 
58 #define RPCDBG_FACILITY	RPCDBG_SVCXPRT
59 
60 
61 static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
62 					 int flags);
63 static int		svc_udp_recvfrom(struct svc_rqst *);
64 static int		svc_udp_sendto(struct svc_rqst *);
65 static void		svc_sock_detach(struct svc_xprt *);
66 static void		svc_tcp_sock_detach(struct svc_xprt *);
67 static void		svc_sock_free(struct svc_xprt *);
68 
69 static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
70 					  struct net *, struct sockaddr *,
71 					  int, int);
72 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
73 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
74 					     struct net *, struct sockaddr *,
75 					     int, int);
76 static void svc_bc_sock_free(struct svc_xprt *xprt);
77 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
78 
79 #ifdef CONFIG_DEBUG_LOCK_ALLOC
80 static struct lock_class_key svc_key[2];
81 static struct lock_class_key svc_slock_key[2];
82 
83 static void svc_reclassify_socket(struct socket *sock)
84 {
85 	struct sock *sk = sock->sk;
86 
87 	if (WARN_ON_ONCE(!sock_allow_reclassification(sk)))
88 		return;
89 
90 	switch (sk->sk_family) {
91 	case AF_INET:
92 		sock_lock_init_class_and_name(sk, "slock-AF_INET-NFSD",
93 					      &svc_slock_key[0],
94 					      "sk_xprt.xpt_lock-AF_INET-NFSD",
95 					      &svc_key[0]);
96 		break;
97 
98 	case AF_INET6:
99 		sock_lock_init_class_and_name(sk, "slock-AF_INET6-NFSD",
100 					      &svc_slock_key[1],
101 					      "sk_xprt.xpt_lock-AF_INET6-NFSD",
102 					      &svc_key[1]);
103 		break;
104 
105 	default:
106 		BUG();
107 	}
108 }
109 #else
110 static void svc_reclassify_socket(struct socket *sock)
111 {
112 }
113 #endif
114 
115 /*
116  * Release an skbuff after use
117  */
118 static void svc_release_skb(struct svc_rqst *rqstp)
119 {
120 	struct sk_buff *skb = rqstp->rq_xprt_ctxt;
121 
122 	if (skb) {
123 		struct svc_sock *svsk =
124 			container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
125 		rqstp->rq_xprt_ctxt = NULL;
126 
127 		dprintk("svc: service %p, releasing skb %p\n", rqstp, skb);
128 		skb_free_datagram_locked(svsk->sk_sk, skb);
129 	}
130 }
131 
132 union svc_pktinfo_u {
133 	struct in_pktinfo pkti;
134 	struct in6_pktinfo pkti6;
135 };
136 #define SVC_PKTINFO_SPACE \
137 	CMSG_SPACE(sizeof(union svc_pktinfo_u))
138 
139 static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
140 {
141 	struct svc_sock *svsk =
142 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
143 	switch (svsk->sk_sk->sk_family) {
144 	case AF_INET: {
145 			struct in_pktinfo *pki = CMSG_DATA(cmh);
146 
147 			cmh->cmsg_level = SOL_IP;
148 			cmh->cmsg_type = IP_PKTINFO;
149 			pki->ipi_ifindex = 0;
150 			pki->ipi_spec_dst.s_addr =
151 				 svc_daddr_in(rqstp)->sin_addr.s_addr;
152 			cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
153 		}
154 		break;
155 
156 	case AF_INET6: {
157 			struct in6_pktinfo *pki = CMSG_DATA(cmh);
158 			struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
159 
160 			cmh->cmsg_level = SOL_IPV6;
161 			cmh->cmsg_type = IPV6_PKTINFO;
162 			pki->ipi6_ifindex = daddr->sin6_scope_id;
163 			pki->ipi6_addr = daddr->sin6_addr;
164 			cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
165 		}
166 		break;
167 	}
168 }
169 
170 /*
171  * send routine intended to be shared by the fore- and back-channel
172  */
173 int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
174 		    struct page *headpage, unsigned long headoffset,
175 		    struct page *tailpage, unsigned long tailoffset)
176 {
177 	int		result;
178 	int		size;
179 	struct page	**ppage = xdr->pages;
180 	size_t		base = xdr->page_base;
181 	unsigned int	pglen = xdr->page_len;
182 	unsigned int	flags = MSG_MORE | MSG_SENDPAGE_NOTLAST;
183 	int		slen;
184 	int		len = 0;
185 
186 	slen = xdr->len;
187 
188 	/* send head */
189 	if (slen == xdr->head[0].iov_len)
190 		flags = 0;
191 	len = kernel_sendpage(sock, headpage, headoffset,
192 				  xdr->head[0].iov_len, flags);
193 	if (len != xdr->head[0].iov_len)
194 		goto out;
195 	slen -= xdr->head[0].iov_len;
196 	if (slen == 0)
197 		goto out;
198 
199 	/* send page data */
200 	size = PAGE_SIZE - base < pglen ? PAGE_SIZE - base : pglen;
201 	while (pglen > 0) {
202 		if (slen == size)
203 			flags = 0;
204 		result = kernel_sendpage(sock, *ppage, base, size, flags);
205 		if (result > 0)
206 			len += result;
207 		if (result != size)
208 			goto out;
209 		slen -= size;
210 		pglen -= size;
211 		size = PAGE_SIZE < pglen ? PAGE_SIZE : pglen;
212 		base = 0;
213 		ppage++;
214 	}
215 
216 	/* send tail */
217 	if (xdr->tail[0].iov_len) {
218 		result = kernel_sendpage(sock, tailpage, tailoffset,
219 				   xdr->tail[0].iov_len, 0);
220 		if (result > 0)
221 			len += result;
222 	}
223 
224 out:
225 	return len;
226 }
227 
228 
229 /*
230  * Generic sendto routine
231  */
232 static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
233 {
234 	struct svc_sock	*svsk =
235 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
236 	struct socket	*sock = svsk->sk_sock;
237 	union {
238 		struct cmsghdr	hdr;
239 		long		all[SVC_PKTINFO_SPACE / sizeof(long)];
240 	} buffer;
241 	struct cmsghdr *cmh = &buffer.hdr;
242 	int		len = 0;
243 	unsigned long tailoff;
244 	unsigned long headoff;
245 	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
246 
247 	if (rqstp->rq_prot == IPPROTO_UDP) {
248 		struct msghdr msg = {
249 			.msg_name	= &rqstp->rq_addr,
250 			.msg_namelen	= rqstp->rq_addrlen,
251 			.msg_control	= cmh,
252 			.msg_controllen	= sizeof(buffer),
253 			.msg_flags	= MSG_MORE,
254 		};
255 
256 		svc_set_cmsg_data(rqstp, cmh);
257 
258 		if (sock_sendmsg(sock, &msg) < 0)
259 			goto out;
260 	}
261 
262 	tailoff = ((unsigned long)xdr->tail[0].iov_base) & (PAGE_SIZE-1);
263 	headoff = 0;
264 	len = svc_send_common(sock, xdr, rqstp->rq_respages[0], headoff,
265 			       rqstp->rq_respages[0], tailoff);
266 
267 out:
268 	dprintk("svc: socket %p sendto([%p %Zu... ], %d) = %d (addr %s)\n",
269 		svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
270 		xdr->len, len, svc_print_addr(rqstp, buf, sizeof(buf)));
271 
272 	return len;
273 }
274 
275 /*
276  * Report socket names for nfsdfs
277  */
278 static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
279 {
280 	const struct sock *sk = svsk->sk_sk;
281 	const char *proto_name = sk->sk_protocol == IPPROTO_UDP ?
282 							"udp" : "tcp";
283 	int len;
284 
285 	switch (sk->sk_family) {
286 	case PF_INET:
287 		len = snprintf(buf, remaining, "ipv4 %s %pI4 %d\n",
288 				proto_name,
289 				&inet_sk(sk)->inet_rcv_saddr,
290 				inet_sk(sk)->inet_num);
291 		break;
292 #if IS_ENABLED(CONFIG_IPV6)
293 	case PF_INET6:
294 		len = snprintf(buf, remaining, "ipv6 %s %pI6 %d\n",
295 				proto_name,
296 				&sk->sk_v6_rcv_saddr,
297 				inet_sk(sk)->inet_num);
298 		break;
299 #endif
300 	default:
301 		len = snprintf(buf, remaining, "*unknown-%d*\n",
302 				sk->sk_family);
303 	}
304 
305 	if (len >= remaining) {
306 		*buf = '\0';
307 		return -ENAMETOOLONG;
308 	}
309 	return len;
310 }
311 
312 /*
313  * Generic recvfrom routine.
314  */
315 static int svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov, int nr,
316 			int buflen)
317 {
318 	struct svc_sock *svsk =
319 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
320 	struct msghdr msg = {
321 		.msg_flags	= MSG_DONTWAIT,
322 	};
323 	int len;
324 
325 	rqstp->rq_xprt_hlen = 0;
326 
327 	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
328 	len = kernel_recvmsg(svsk->sk_sock, &msg, iov, nr, buflen,
329 				msg.msg_flags);
330 	/* If we read a full record, then assume there may be more
331 	 * data to read (stream based sockets only!)
332 	 */
333 	if (len == buflen)
334 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
335 
336 	dprintk("svc: socket %p recvfrom(%p, %Zu) = %d\n",
337 		svsk, iov[0].iov_base, iov[0].iov_len, len);
338 	return len;
339 }
340 
341 static int svc_partial_recvfrom(struct svc_rqst *rqstp,
342 				struct kvec *iov, int nr,
343 				int buflen, unsigned int base)
344 {
345 	size_t save_iovlen;
346 	void *save_iovbase;
347 	unsigned int i;
348 	int ret;
349 
350 	if (base == 0)
351 		return svc_recvfrom(rqstp, iov, nr, buflen);
352 
353 	for (i = 0; i < nr; i++) {
354 		if (iov[i].iov_len > base)
355 			break;
356 		base -= iov[i].iov_len;
357 	}
358 	save_iovlen = iov[i].iov_len;
359 	save_iovbase = iov[i].iov_base;
360 	iov[i].iov_len -= base;
361 	iov[i].iov_base += base;
362 	ret = svc_recvfrom(rqstp, &iov[i], nr - i, buflen);
363 	iov[i].iov_len = save_iovlen;
364 	iov[i].iov_base = save_iovbase;
365 	return ret;
366 }
367 
368 /*
369  * Set socket snd and rcv buffer lengths
370  */
371 static void svc_sock_setbufsize(struct socket *sock, unsigned int snd,
372 				unsigned int rcv)
373 {
374 #if 0
375 	mm_segment_t	oldfs;
376 	oldfs = get_fs(); set_fs(KERNEL_DS);
377 	sock_setsockopt(sock, SOL_SOCKET, SO_SNDBUF,
378 			(char*)&snd, sizeof(snd));
379 	sock_setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
380 			(char*)&rcv, sizeof(rcv));
381 #else
382 	/* sock_setsockopt limits use to sysctl_?mem_max,
383 	 * which isn't acceptable.  Until that is made conditional
384 	 * on not having CAP_SYS_RESOURCE or similar, we go direct...
385 	 * DaveM said I could!
386 	 */
387 	lock_sock(sock->sk);
388 	sock->sk->sk_sndbuf = snd * 2;
389 	sock->sk->sk_rcvbuf = rcv * 2;
390 	sock->sk->sk_write_space(sock->sk);
391 	release_sock(sock->sk);
392 #endif
393 }
394 
395 static int svc_sock_secure_port(struct svc_rqst *rqstp)
396 {
397 	return svc_port_is_privileged(svc_addr(rqstp));
398 }
399 
400 /*
401  * INET callback when data has been received on the socket.
402  */
403 static void svc_data_ready(struct sock *sk)
404 {
405 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
406 
407 	if (svsk) {
408 		dprintk("svc: socket %p(inet %p), busy=%d\n",
409 			svsk, sk,
410 			test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
411 		svsk->sk_odata(sk);
412 		if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
413 			svc_xprt_enqueue(&svsk->sk_xprt);
414 	}
415 }
416 
417 /*
418  * INET callback when space is newly available on the socket.
419  */
420 static void svc_write_space(struct sock *sk)
421 {
422 	struct svc_sock	*svsk = (struct svc_sock *)(sk->sk_user_data);
423 
424 	if (svsk) {
425 		dprintk("svc: socket %p(inet %p), write_space busy=%d\n",
426 			svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
427 		svsk->sk_owspace(sk);
428 		svc_xprt_enqueue(&svsk->sk_xprt);
429 	}
430 }
431 
432 static int svc_tcp_has_wspace(struct svc_xprt *xprt)
433 {
434 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
435 
436 	if (test_bit(XPT_LISTENER, &xprt->xpt_flags))
437 		return 1;
438 	return !test_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
439 }
440 
441 static void svc_tcp_kill_temp_xprt(struct svc_xprt *xprt)
442 {
443 	struct svc_sock *svsk;
444 	struct socket *sock;
445 	struct linger no_linger = {
446 		.l_onoff = 1,
447 		.l_linger = 0,
448 	};
449 
450 	svsk = container_of(xprt, struct svc_sock, sk_xprt);
451 	sock = svsk->sk_sock;
452 	kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER,
453 			  (char *)&no_linger, sizeof(no_linger));
454 }
455 
456 /*
457  * See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
458  */
459 static int svc_udp_get_dest_address4(struct svc_rqst *rqstp,
460 				     struct cmsghdr *cmh)
461 {
462 	struct in_pktinfo *pki = CMSG_DATA(cmh);
463 	struct sockaddr_in *daddr = svc_daddr_in(rqstp);
464 
465 	if (cmh->cmsg_type != IP_PKTINFO)
466 		return 0;
467 
468 	daddr->sin_family = AF_INET;
469 	daddr->sin_addr.s_addr = pki->ipi_spec_dst.s_addr;
470 	return 1;
471 }
472 
473 /*
474  * See net/ipv6/datagram.c : ip6_datagram_recv_ctl
475  */
476 static int svc_udp_get_dest_address6(struct svc_rqst *rqstp,
477 				     struct cmsghdr *cmh)
478 {
479 	struct in6_pktinfo *pki = CMSG_DATA(cmh);
480 	struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
481 
482 	if (cmh->cmsg_type != IPV6_PKTINFO)
483 		return 0;
484 
485 	daddr->sin6_family = AF_INET6;
486 	daddr->sin6_addr = pki->ipi6_addr;
487 	daddr->sin6_scope_id = pki->ipi6_ifindex;
488 	return 1;
489 }
490 
491 /*
492  * Copy the UDP datagram's destination address to the rqstp structure.
493  * The 'destination' address in this case is the address to which the
494  * peer sent the datagram, i.e. our local address. For multihomed
495  * hosts, this can change from msg to msg. Note that only the IP
496  * address changes, the port number should remain the same.
497  */
498 static int svc_udp_get_dest_address(struct svc_rqst *rqstp,
499 				    struct cmsghdr *cmh)
500 {
501 	switch (cmh->cmsg_level) {
502 	case SOL_IP:
503 		return svc_udp_get_dest_address4(rqstp, cmh);
504 	case SOL_IPV6:
505 		return svc_udp_get_dest_address6(rqstp, cmh);
506 	}
507 
508 	return 0;
509 }
510 
511 /*
512  * Receive a datagram from a UDP socket.
513  */
514 static int svc_udp_recvfrom(struct svc_rqst *rqstp)
515 {
516 	struct svc_sock	*svsk =
517 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
518 	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
519 	struct sk_buff	*skb;
520 	union {
521 		struct cmsghdr	hdr;
522 		long		all[SVC_PKTINFO_SPACE / sizeof(long)];
523 	} buffer;
524 	struct cmsghdr *cmh = &buffer.hdr;
525 	struct msghdr msg = {
526 		.msg_name = svc_addr(rqstp),
527 		.msg_control = cmh,
528 		.msg_controllen = sizeof(buffer),
529 		.msg_flags = MSG_DONTWAIT,
530 	};
531 	size_t len;
532 	int err;
533 
534 	if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
535 	    /* udp sockets need large rcvbuf as all pending
536 	     * requests are still in that buffer.  sndbuf must
537 	     * also be large enough that there is enough space
538 	     * for one reply per thread.  We count all threads
539 	     * rather than threads in a particular pool, which
540 	     * provides an upper bound on the number of threads
541 	     * which will access the socket.
542 	     */
543 	    svc_sock_setbufsize(svsk->sk_sock,
544 				(serv->sv_nrthreads+3) * serv->sv_max_mesg,
545 				(serv->sv_nrthreads+3) * serv->sv_max_mesg);
546 
547 	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
548 	skb = NULL;
549 	err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
550 			     0, 0, MSG_PEEK | MSG_DONTWAIT);
551 	if (err >= 0)
552 		skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err);
553 
554 	if (skb == NULL) {
555 		if (err != -EAGAIN) {
556 			/* possibly an icmp error */
557 			dprintk("svc: recvfrom returned error %d\n", -err);
558 			set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
559 		}
560 		return 0;
561 	}
562 	len = svc_addr_len(svc_addr(rqstp));
563 	rqstp->rq_addrlen = len;
564 	if (skb->tstamp.tv64 == 0) {
565 		skb->tstamp = ktime_get_real();
566 		/* Don't enable netstamp, sunrpc doesn't
567 		   need that much accuracy */
568 	}
569 	svsk->sk_sk->sk_stamp = skb->tstamp;
570 	set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
571 
572 	len  = skb->len;
573 	rqstp->rq_arg.len = len;
574 
575 	rqstp->rq_prot = IPPROTO_UDP;
576 
577 	if (!svc_udp_get_dest_address(rqstp, cmh)) {
578 		net_warn_ratelimited("svc: received unknown control message %d/%d; dropping RPC reply datagram\n",
579 				     cmh->cmsg_level, cmh->cmsg_type);
580 		goto out_free;
581 	}
582 	rqstp->rq_daddrlen = svc_addr_len(svc_daddr(rqstp));
583 
584 	if (skb_is_nonlinear(skb)) {
585 		/* we have to copy */
586 		local_bh_disable();
587 		if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
588 			local_bh_enable();
589 			/* checksum error */
590 			goto out_free;
591 		}
592 		local_bh_enable();
593 		skb_free_datagram_locked(svsk->sk_sk, skb);
594 	} else {
595 		/* we can use it in-place */
596 		rqstp->rq_arg.head[0].iov_base = skb->data;
597 		rqstp->rq_arg.head[0].iov_len = len;
598 		if (skb_checksum_complete(skb))
599 			goto out_free;
600 		rqstp->rq_xprt_ctxt = skb;
601 	}
602 
603 	rqstp->rq_arg.page_base = 0;
604 	if (len <= rqstp->rq_arg.head[0].iov_len) {
605 		rqstp->rq_arg.head[0].iov_len = len;
606 		rqstp->rq_arg.page_len = 0;
607 		rqstp->rq_respages = rqstp->rq_pages+1;
608 	} else {
609 		rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
610 		rqstp->rq_respages = rqstp->rq_pages + 1 +
611 			DIV_ROUND_UP(rqstp->rq_arg.page_len, PAGE_SIZE);
612 	}
613 	rqstp->rq_next_page = rqstp->rq_respages+1;
614 
615 	if (serv->sv_stats)
616 		serv->sv_stats->netudpcnt++;
617 
618 	return len;
619 out_free:
620 	trace_kfree_skb(skb, svc_udp_recvfrom);
621 	skb_free_datagram_locked(svsk->sk_sk, skb);
622 	return 0;
623 }
624 
625 static int
626 svc_udp_sendto(struct svc_rqst *rqstp)
627 {
628 	int		error;
629 
630 	error = svc_sendto(rqstp, &rqstp->rq_res);
631 	if (error == -ECONNREFUSED)
632 		/* ICMP error on earlier request. */
633 		error = svc_sendto(rqstp, &rqstp->rq_res);
634 
635 	return error;
636 }
637 
638 static void svc_udp_prep_reply_hdr(struct svc_rqst *rqstp)
639 {
640 }
641 
642 static int svc_udp_has_wspace(struct svc_xprt *xprt)
643 {
644 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
645 	struct svc_serv	*serv = xprt->xpt_server;
646 	unsigned long required;
647 
648 	/*
649 	 * Set the SOCK_NOSPACE flag before checking the available
650 	 * sock space.
651 	 */
652 	set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
653 	required = atomic_read(&svsk->sk_xprt.xpt_reserved) + serv->sv_max_mesg;
654 	if (required*2 > sock_wspace(svsk->sk_sk))
655 		return 0;
656 	clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
657 	return 1;
658 }
659 
660 static struct svc_xprt *svc_udp_accept(struct svc_xprt *xprt)
661 {
662 	BUG();
663 	return NULL;
664 }
665 
666 static void svc_udp_kill_temp_xprt(struct svc_xprt *xprt)
667 {
668 }
669 
670 static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
671 				       struct net *net,
672 				       struct sockaddr *sa, int salen,
673 				       int flags)
674 {
675 	return svc_create_socket(serv, IPPROTO_UDP, net, sa, salen, flags);
676 }
677 
678 static struct svc_xprt_ops svc_udp_ops = {
679 	.xpo_create = svc_udp_create,
680 	.xpo_recvfrom = svc_udp_recvfrom,
681 	.xpo_sendto = svc_udp_sendto,
682 	.xpo_release_rqst = svc_release_skb,
683 	.xpo_detach = svc_sock_detach,
684 	.xpo_free = svc_sock_free,
685 	.xpo_prep_reply_hdr = svc_udp_prep_reply_hdr,
686 	.xpo_has_wspace = svc_udp_has_wspace,
687 	.xpo_accept = svc_udp_accept,
688 	.xpo_secure_port = svc_sock_secure_port,
689 	.xpo_kill_temp_xprt = svc_udp_kill_temp_xprt,
690 };
691 
692 static struct svc_xprt_class svc_udp_class = {
693 	.xcl_name = "udp",
694 	.xcl_owner = THIS_MODULE,
695 	.xcl_ops = &svc_udp_ops,
696 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
697 	.xcl_ident = XPRT_TRANSPORT_UDP,
698 };
699 
700 static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
701 {
702 	int err, level, optname, one = 1;
703 
704 	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
705 		      &svsk->sk_xprt, serv);
706 	clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
707 	svsk->sk_sk->sk_data_ready = svc_data_ready;
708 	svsk->sk_sk->sk_write_space = svc_write_space;
709 
710 	/* initialise setting must have enough space to
711 	 * receive and respond to one request.
712 	 * svc_udp_recvfrom will re-adjust if necessary
713 	 */
714 	svc_sock_setbufsize(svsk->sk_sock,
715 			    3 * svsk->sk_xprt.xpt_server->sv_max_mesg,
716 			    3 * svsk->sk_xprt.xpt_server->sv_max_mesg);
717 
718 	/* data might have come in before data_ready set up */
719 	set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
720 	set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
721 
722 	/* make sure we get destination address info */
723 	switch (svsk->sk_sk->sk_family) {
724 	case AF_INET:
725 		level = SOL_IP;
726 		optname = IP_PKTINFO;
727 		break;
728 	case AF_INET6:
729 		level = SOL_IPV6;
730 		optname = IPV6_RECVPKTINFO;
731 		break;
732 	default:
733 		BUG();
734 	}
735 	err = kernel_setsockopt(svsk->sk_sock, level, optname,
736 					(char *)&one, sizeof(one));
737 	dprintk("svc: kernel_setsockopt returned %d\n", err);
738 }
739 
740 /*
741  * A data_ready event on a listening socket means there's a connection
742  * pending. Do not use state_change as a substitute for it.
743  */
744 static void svc_tcp_listen_data_ready(struct sock *sk)
745 {
746 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
747 
748 	dprintk("svc: socket %p TCP (listen) state change %d\n",
749 		sk, sk->sk_state);
750 
751 	if (svsk)
752 		svsk->sk_odata(sk);
753 	/*
754 	 * This callback may called twice when a new connection
755 	 * is established as a child socket inherits everything
756 	 * from a parent LISTEN socket.
757 	 * 1) data_ready method of the parent socket will be called
758 	 *    when one of child sockets become ESTABLISHED.
759 	 * 2) data_ready method of the child socket may be called
760 	 *    when it receives data before the socket is accepted.
761 	 * In case of 2, we should ignore it silently.
762 	 */
763 	if (sk->sk_state == TCP_LISTEN) {
764 		if (svsk) {
765 			set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
766 			svc_xprt_enqueue(&svsk->sk_xprt);
767 		} else
768 			printk("svc: socket %p: no user data\n", sk);
769 	}
770 }
771 
772 /*
773  * A state change on a connected socket means it's dying or dead.
774  */
775 static void svc_tcp_state_change(struct sock *sk)
776 {
777 	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
778 
779 	dprintk("svc: socket %p TCP (connected) state change %d (svsk %p)\n",
780 		sk, sk->sk_state, sk->sk_user_data);
781 
782 	if (!svsk)
783 		printk("svc: socket %p: no user data\n", sk);
784 	else {
785 		svsk->sk_ostate(sk);
786 		if (sk->sk_state != TCP_ESTABLISHED) {
787 			set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
788 			svc_xprt_enqueue(&svsk->sk_xprt);
789 		}
790 	}
791 }
792 
793 /*
794  * Accept a TCP connection
795  */
796 static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
797 {
798 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
799 	struct sockaddr_storage addr;
800 	struct sockaddr	*sin = (struct sockaddr *) &addr;
801 	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
802 	struct socket	*sock = svsk->sk_sock;
803 	struct socket	*newsock;
804 	struct svc_sock	*newsvsk;
805 	int		err, slen;
806 	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
807 
808 	dprintk("svc: tcp_accept %p sock %p\n", svsk, sock);
809 	if (!sock)
810 		return NULL;
811 
812 	clear_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
813 	err = kernel_accept(sock, &newsock, O_NONBLOCK);
814 	if (err < 0) {
815 		if (err == -ENOMEM)
816 			printk(KERN_WARNING "%s: no more sockets!\n",
817 			       serv->sv_name);
818 		else if (err != -EAGAIN)
819 			net_warn_ratelimited("%s: accept failed (err %d)!\n",
820 					     serv->sv_name, -err);
821 		return NULL;
822 	}
823 	set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
824 
825 	err = kernel_getpeername(newsock, sin, &slen);
826 	if (err < 0) {
827 		net_warn_ratelimited("%s: peername failed (err %d)!\n",
828 				     serv->sv_name, -err);
829 		goto failed;		/* aborted connection or whatever */
830 	}
831 
832 	/* Ideally, we would want to reject connections from unauthorized
833 	 * hosts here, but when we get encryption, the IP of the host won't
834 	 * tell us anything.  For now just warn about unpriv connections.
835 	 */
836 	if (!svc_port_is_privileged(sin)) {
837 		dprintk("%s: connect from unprivileged port: %s\n",
838 			serv->sv_name,
839 			__svc_print_addr(sin, buf, sizeof(buf)));
840 	}
841 	dprintk("%s: connect from %s\n", serv->sv_name,
842 		__svc_print_addr(sin, buf, sizeof(buf)));
843 
844 	/* Reset the inherited callbacks before calling svc_setup_socket */
845 	newsock->sk->sk_state_change = svsk->sk_ostate;
846 	newsock->sk->sk_data_ready = svsk->sk_odata;
847 	newsock->sk->sk_write_space = svsk->sk_owspace;
848 
849 	/* make sure that a write doesn't block forever when
850 	 * low on memory
851 	 */
852 	newsock->sk->sk_sndtimeo = HZ*30;
853 
854 	newsvsk = svc_setup_socket(serv, newsock,
855 				 (SVC_SOCK_ANONYMOUS | SVC_SOCK_TEMPORARY));
856 	if (IS_ERR(newsvsk))
857 		goto failed;
858 	svc_xprt_set_remote(&newsvsk->sk_xprt, sin, slen);
859 	err = kernel_getsockname(newsock, sin, &slen);
860 	if (unlikely(err < 0)) {
861 		dprintk("svc_tcp_accept: kernel_getsockname error %d\n", -err);
862 		slen = offsetof(struct sockaddr, sa_data);
863 	}
864 	svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
865 
866 	if (sock_is_loopback(newsock->sk))
867 		set_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
868 	else
869 		clear_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
870 	if (serv->sv_stats)
871 		serv->sv_stats->nettcpconn++;
872 
873 	return &newsvsk->sk_xprt;
874 
875 failed:
876 	sock_release(newsock);
877 	return NULL;
878 }
879 
880 static unsigned int svc_tcp_restore_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
881 {
882 	unsigned int i, len, npages;
883 
884 	if (svsk->sk_datalen == 0)
885 		return 0;
886 	len = svsk->sk_datalen;
887 	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
888 	for (i = 0; i < npages; i++) {
889 		if (rqstp->rq_pages[i] != NULL)
890 			put_page(rqstp->rq_pages[i]);
891 		BUG_ON(svsk->sk_pages[i] == NULL);
892 		rqstp->rq_pages[i] = svsk->sk_pages[i];
893 		svsk->sk_pages[i] = NULL;
894 	}
895 	rqstp->rq_arg.head[0].iov_base = page_address(rqstp->rq_pages[0]);
896 	return len;
897 }
898 
899 static void svc_tcp_save_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
900 {
901 	unsigned int i, len, npages;
902 
903 	if (svsk->sk_datalen == 0)
904 		return;
905 	len = svsk->sk_datalen;
906 	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
907 	for (i = 0; i < npages; i++) {
908 		svsk->sk_pages[i] = rqstp->rq_pages[i];
909 		rqstp->rq_pages[i] = NULL;
910 	}
911 }
912 
913 static void svc_tcp_clear_pages(struct svc_sock *svsk)
914 {
915 	unsigned int i, len, npages;
916 
917 	if (svsk->sk_datalen == 0)
918 		goto out;
919 	len = svsk->sk_datalen;
920 	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
921 	for (i = 0; i < npages; i++) {
922 		if (svsk->sk_pages[i] == NULL) {
923 			WARN_ON_ONCE(1);
924 			continue;
925 		}
926 		put_page(svsk->sk_pages[i]);
927 		svsk->sk_pages[i] = NULL;
928 	}
929 out:
930 	svsk->sk_tcplen = 0;
931 	svsk->sk_datalen = 0;
932 }
933 
934 /*
935  * Receive fragment record header.
936  * If we haven't gotten the record length yet, get the next four bytes.
937  */
938 static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
939 {
940 	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
941 	unsigned int want;
942 	int len;
943 
944 	if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
945 		struct kvec	iov;
946 
947 		want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
948 		iov.iov_base = ((char *) &svsk->sk_reclen) + svsk->sk_tcplen;
949 		iov.iov_len  = want;
950 		if ((len = svc_recvfrom(rqstp, &iov, 1, want)) < 0)
951 			goto error;
952 		svsk->sk_tcplen += len;
953 
954 		if (len < want) {
955 			dprintk("svc: short recvfrom while reading record "
956 				"length (%d of %d)\n", len, want);
957 			return -EAGAIN;
958 		}
959 
960 		dprintk("svc: TCP record, %d bytes\n", svc_sock_reclen(svsk));
961 		if (svc_sock_reclen(svsk) + svsk->sk_datalen >
962 							serv->sv_max_mesg) {
963 			net_notice_ratelimited("RPC: fragment too large: %d\n",
964 					svc_sock_reclen(svsk));
965 			goto err_delete;
966 		}
967 	}
968 
969 	return svc_sock_reclen(svsk);
970 error:
971 	dprintk("RPC: TCP recv_record got %d\n", len);
972 	return len;
973 err_delete:
974 	set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
975 	return -EAGAIN;
976 }
977 
978 static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
979 {
980 	struct rpc_xprt *bc_xprt = svsk->sk_xprt.xpt_bc_xprt;
981 	struct rpc_rqst *req = NULL;
982 	struct kvec *src, *dst;
983 	__be32 *p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
984 	__be32 xid;
985 	__be32 calldir;
986 
987 	xid = *p++;
988 	calldir = *p;
989 
990 	if (!bc_xprt)
991 		return -EAGAIN;
992 	spin_lock_bh(&bc_xprt->transport_lock);
993 	req = xprt_lookup_rqst(bc_xprt, xid);
994 	if (!req)
995 		goto unlock_notfound;
996 
997 	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
998 	/*
999 	 * XXX!: cheating for now!  Only copying HEAD.
1000 	 * But we know this is good enough for now (in fact, for any
1001 	 * callback reply in the forseeable future).
1002 	 */
1003 	dst = &req->rq_private_buf.head[0];
1004 	src = &rqstp->rq_arg.head[0];
1005 	if (dst->iov_len < src->iov_len)
1006 		goto unlock_eagain; /* whatever; just giving up. */
1007 	memcpy(dst->iov_base, src->iov_base, src->iov_len);
1008 	xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len);
1009 	rqstp->rq_arg.len = 0;
1010 	spin_unlock_bh(&bc_xprt->transport_lock);
1011 	return 0;
1012 unlock_notfound:
1013 	printk(KERN_NOTICE
1014 		"%s: Got unrecognized reply: "
1015 		"calldir 0x%x xpt_bc_xprt %p xid %08x\n",
1016 		__func__, ntohl(calldir),
1017 		bc_xprt, ntohl(xid));
1018 unlock_eagain:
1019 	spin_unlock_bh(&bc_xprt->transport_lock);
1020 	return -EAGAIN;
1021 }
1022 
1023 static int copy_pages_to_kvecs(struct kvec *vec, struct page **pages, int len)
1024 {
1025 	int i = 0;
1026 	int t = 0;
1027 
1028 	while (t < len) {
1029 		vec[i].iov_base = page_address(pages[i]);
1030 		vec[i].iov_len = PAGE_SIZE;
1031 		i++;
1032 		t += PAGE_SIZE;
1033 	}
1034 	return i;
1035 }
1036 
1037 static void svc_tcp_fragment_received(struct svc_sock *svsk)
1038 {
1039 	/* If we have more data, signal svc_xprt_enqueue() to try again */
1040 	dprintk("svc: TCP %s record (%d bytes)\n",
1041 		svc_sock_final_rec(svsk) ? "final" : "nonfinal",
1042 		svc_sock_reclen(svsk));
1043 	svsk->sk_tcplen = 0;
1044 	svsk->sk_reclen = 0;
1045 }
1046 
1047 /*
1048  * Receive data from a TCP socket.
1049  */
1050 static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
1051 {
1052 	struct svc_sock	*svsk =
1053 		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
1054 	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
1055 	int		len;
1056 	struct kvec *vec;
1057 	unsigned int want, base;
1058 	__be32 *p;
1059 	__be32 calldir;
1060 	int pnum;
1061 
1062 	dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
1063 		svsk, test_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags),
1064 		test_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags),
1065 		test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
1066 
1067 	len = svc_tcp_recv_record(svsk, rqstp);
1068 	if (len < 0)
1069 		goto error;
1070 
1071 	base = svc_tcp_restore_pages(svsk, rqstp);
1072 	want = svc_sock_reclen(svsk) - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
1073 
1074 	vec = rqstp->rq_vec;
1075 
1076 	pnum = copy_pages_to_kvecs(&vec[0], &rqstp->rq_pages[0],
1077 						svsk->sk_datalen + want);
1078 
1079 	rqstp->rq_respages = &rqstp->rq_pages[pnum];
1080 	rqstp->rq_next_page = rqstp->rq_respages + 1;
1081 
1082 	/* Now receive data */
1083 	len = svc_partial_recvfrom(rqstp, vec, pnum, want, base);
1084 	if (len >= 0) {
1085 		svsk->sk_tcplen += len;
1086 		svsk->sk_datalen += len;
1087 	}
1088 	if (len != want || !svc_sock_final_rec(svsk)) {
1089 		svc_tcp_save_pages(svsk, rqstp);
1090 		if (len < 0 && len != -EAGAIN)
1091 			goto err_delete;
1092 		if (len == want)
1093 			svc_tcp_fragment_received(svsk);
1094 		else
1095 			dprintk("svc: incomplete TCP record (%d of %d)\n",
1096 				(int)(svsk->sk_tcplen - sizeof(rpc_fraghdr)),
1097 				svc_sock_reclen(svsk));
1098 		goto err_noclose;
1099 	}
1100 
1101 	if (svsk->sk_datalen < 8) {
1102 		svsk->sk_datalen = 0;
1103 		goto err_delete; /* client is nuts. */
1104 	}
1105 
1106 	rqstp->rq_arg.len = svsk->sk_datalen;
1107 	rqstp->rq_arg.page_base = 0;
1108 	if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
1109 		rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
1110 		rqstp->rq_arg.page_len = 0;
1111 	} else
1112 		rqstp->rq_arg.page_len = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1113 
1114 	rqstp->rq_xprt_ctxt   = NULL;
1115 	rqstp->rq_prot	      = IPPROTO_TCP;
1116 	if (test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags))
1117 		set_bit(RQ_LOCAL, &rqstp->rq_flags);
1118 	else
1119 		clear_bit(RQ_LOCAL, &rqstp->rq_flags);
1120 
1121 	p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
1122 	calldir = p[1];
1123 	if (calldir)
1124 		len = receive_cb_reply(svsk, rqstp);
1125 
1126 	/* Reset TCP read info */
1127 	svsk->sk_datalen = 0;
1128 	svc_tcp_fragment_received(svsk);
1129 
1130 	if (len < 0)
1131 		goto error;
1132 
1133 	svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt);
1134 	if (serv->sv_stats)
1135 		serv->sv_stats->nettcpcnt++;
1136 
1137 	return rqstp->rq_arg.len;
1138 
1139 error:
1140 	if (len != -EAGAIN)
1141 		goto err_delete;
1142 	dprintk("RPC: TCP recvfrom got EAGAIN\n");
1143 	return 0;
1144 err_delete:
1145 	printk(KERN_NOTICE "%s: recvfrom returned errno %d\n",
1146 	       svsk->sk_xprt.xpt_server->sv_name, -len);
1147 	set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
1148 err_noclose:
1149 	return 0;	/* record not complete */
1150 }
1151 
1152 /*
1153  * Send out data on TCP socket.
1154  */
1155 static int svc_tcp_sendto(struct svc_rqst *rqstp)
1156 {
1157 	struct xdr_buf	*xbufp = &rqstp->rq_res;
1158 	int sent;
1159 	__be32 reclen;
1160 
1161 	/* Set up the first element of the reply kvec.
1162 	 * Any other kvecs that may be in use have been taken
1163 	 * care of by the server implementation itself.
1164 	 */
1165 	reclen = htonl(0x80000000|((xbufp->len ) - 4));
1166 	memcpy(xbufp->head[0].iov_base, &reclen, 4);
1167 
1168 	sent = svc_sendto(rqstp, &rqstp->rq_res);
1169 	if (sent != xbufp->len) {
1170 		printk(KERN_NOTICE
1171 		       "rpc-srv/tcp: %s: %s %d when sending %d bytes "
1172 		       "- shutting down socket\n",
1173 		       rqstp->rq_xprt->xpt_server->sv_name,
1174 		       (sent<0)?"got error":"sent only",
1175 		       sent, xbufp->len);
1176 		set_bit(XPT_CLOSE, &rqstp->rq_xprt->xpt_flags);
1177 		svc_xprt_enqueue(rqstp->rq_xprt);
1178 		sent = -EAGAIN;
1179 	}
1180 	return sent;
1181 }
1182 
1183 /*
1184  * Setup response header. TCP has a 4B record length field.
1185  */
1186 static void svc_tcp_prep_reply_hdr(struct svc_rqst *rqstp)
1187 {
1188 	struct kvec *resv = &rqstp->rq_res.head[0];
1189 
1190 	/* tcp needs a space for the record length... */
1191 	svc_putnl(resv, 0);
1192 }
1193 
1194 static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
1195 				       struct net *net,
1196 				       struct sockaddr *sa, int salen,
1197 				       int flags)
1198 {
1199 	return svc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
1200 }
1201 
1202 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1203 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
1204 					     struct net *, struct sockaddr *,
1205 					     int, int);
1206 static void svc_bc_sock_free(struct svc_xprt *xprt);
1207 
1208 static struct svc_xprt *svc_bc_tcp_create(struct svc_serv *serv,
1209 				       struct net *net,
1210 				       struct sockaddr *sa, int salen,
1211 				       int flags)
1212 {
1213 	return svc_bc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
1214 }
1215 
1216 static void svc_bc_tcp_sock_detach(struct svc_xprt *xprt)
1217 {
1218 }
1219 
1220 static struct svc_xprt_ops svc_tcp_bc_ops = {
1221 	.xpo_create = svc_bc_tcp_create,
1222 	.xpo_detach = svc_bc_tcp_sock_detach,
1223 	.xpo_free = svc_bc_sock_free,
1224 	.xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
1225 	.xpo_secure_port = svc_sock_secure_port,
1226 };
1227 
1228 static struct svc_xprt_class svc_tcp_bc_class = {
1229 	.xcl_name = "tcp-bc",
1230 	.xcl_owner = THIS_MODULE,
1231 	.xcl_ops = &svc_tcp_bc_ops,
1232 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
1233 };
1234 
1235 static void svc_init_bc_xprt_sock(void)
1236 {
1237 	svc_reg_xprt_class(&svc_tcp_bc_class);
1238 }
1239 
1240 static void svc_cleanup_bc_xprt_sock(void)
1241 {
1242 	svc_unreg_xprt_class(&svc_tcp_bc_class);
1243 }
1244 #else /* CONFIG_SUNRPC_BACKCHANNEL */
1245 static void svc_init_bc_xprt_sock(void)
1246 {
1247 }
1248 
1249 static void svc_cleanup_bc_xprt_sock(void)
1250 {
1251 }
1252 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1253 
1254 static struct svc_xprt_ops svc_tcp_ops = {
1255 	.xpo_create = svc_tcp_create,
1256 	.xpo_recvfrom = svc_tcp_recvfrom,
1257 	.xpo_sendto = svc_tcp_sendto,
1258 	.xpo_release_rqst = svc_release_skb,
1259 	.xpo_detach = svc_tcp_sock_detach,
1260 	.xpo_free = svc_sock_free,
1261 	.xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
1262 	.xpo_has_wspace = svc_tcp_has_wspace,
1263 	.xpo_accept = svc_tcp_accept,
1264 	.xpo_secure_port = svc_sock_secure_port,
1265 	.xpo_kill_temp_xprt = svc_tcp_kill_temp_xprt,
1266 };
1267 
1268 static struct svc_xprt_class svc_tcp_class = {
1269 	.xcl_name = "tcp",
1270 	.xcl_owner = THIS_MODULE,
1271 	.xcl_ops = &svc_tcp_ops,
1272 	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
1273 	.xcl_ident = XPRT_TRANSPORT_TCP,
1274 };
1275 
1276 void svc_init_xprt_sock(void)
1277 {
1278 	svc_reg_xprt_class(&svc_tcp_class);
1279 	svc_reg_xprt_class(&svc_udp_class);
1280 	svc_init_bc_xprt_sock();
1281 }
1282 
1283 void svc_cleanup_xprt_sock(void)
1284 {
1285 	svc_unreg_xprt_class(&svc_tcp_class);
1286 	svc_unreg_xprt_class(&svc_udp_class);
1287 	svc_cleanup_bc_xprt_sock();
1288 }
1289 
1290 static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
1291 {
1292 	struct sock	*sk = svsk->sk_sk;
1293 
1294 	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_tcp_class,
1295 		      &svsk->sk_xprt, serv);
1296 	set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
1297 	if (sk->sk_state == TCP_LISTEN) {
1298 		dprintk("setting up TCP socket for listening\n");
1299 		set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
1300 		sk->sk_data_ready = svc_tcp_listen_data_ready;
1301 		set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
1302 	} else {
1303 		dprintk("setting up TCP socket for reading\n");
1304 		sk->sk_state_change = svc_tcp_state_change;
1305 		sk->sk_data_ready = svc_data_ready;
1306 		sk->sk_write_space = svc_write_space;
1307 
1308 		svsk->sk_reclen = 0;
1309 		svsk->sk_tcplen = 0;
1310 		svsk->sk_datalen = 0;
1311 		memset(&svsk->sk_pages[0], 0, sizeof(svsk->sk_pages));
1312 
1313 		tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1314 
1315 		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
1316 		switch (sk->sk_state) {
1317 		case TCP_SYN_RECV:
1318 		case TCP_ESTABLISHED:
1319 			break;
1320 		default:
1321 			set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
1322 		}
1323 	}
1324 }
1325 
1326 void svc_sock_update_bufs(struct svc_serv *serv)
1327 {
1328 	/*
1329 	 * The number of server threads has changed. Update
1330 	 * rcvbuf and sndbuf accordingly on all sockets
1331 	 */
1332 	struct svc_sock *svsk;
1333 
1334 	spin_lock_bh(&serv->sv_lock);
1335 	list_for_each_entry(svsk, &serv->sv_permsocks, sk_xprt.xpt_list)
1336 		set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
1337 	spin_unlock_bh(&serv->sv_lock);
1338 }
1339 EXPORT_SYMBOL_GPL(svc_sock_update_bufs);
1340 
1341 /*
1342  * Initialize socket for RPC use and create svc_sock struct
1343  */
1344 static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
1345 						struct socket *sock,
1346 						int flags)
1347 {
1348 	struct svc_sock	*svsk;
1349 	struct sock	*inet;
1350 	int		pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
1351 	int		err = 0;
1352 
1353 	dprintk("svc: svc_setup_socket %p\n", sock);
1354 	svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
1355 	if (!svsk)
1356 		return ERR_PTR(-ENOMEM);
1357 
1358 	inet = sock->sk;
1359 
1360 	/* Register socket with portmapper */
1361 	if (pmap_register)
1362 		err = svc_register(serv, sock_net(sock->sk), inet->sk_family,
1363 				     inet->sk_protocol,
1364 				     ntohs(inet_sk(inet)->inet_sport));
1365 
1366 	if (err < 0) {
1367 		kfree(svsk);
1368 		return ERR_PTR(err);
1369 	}
1370 
1371 	inet->sk_user_data = svsk;
1372 	svsk->sk_sock = sock;
1373 	svsk->sk_sk = inet;
1374 	svsk->sk_ostate = inet->sk_state_change;
1375 	svsk->sk_odata = inet->sk_data_ready;
1376 	svsk->sk_owspace = inet->sk_write_space;
1377 
1378 	/* Initialize the socket */
1379 	if (sock->type == SOCK_DGRAM)
1380 		svc_udp_init(svsk, serv);
1381 	else
1382 		svc_tcp_init(svsk, serv);
1383 
1384 	dprintk("svc: svc_setup_socket created %p (inet %p), "
1385 			"listen %d close %d\n",
1386 			svsk, svsk->sk_sk,
1387 			test_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags),
1388 			test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
1389 
1390 	return svsk;
1391 }
1392 
1393 bool svc_alien_sock(struct net *net, int fd)
1394 {
1395 	int err;
1396 	struct socket *sock = sockfd_lookup(fd, &err);
1397 	bool ret = false;
1398 
1399 	if (!sock)
1400 		goto out;
1401 	if (sock_net(sock->sk) != net)
1402 		ret = true;
1403 	sockfd_put(sock);
1404 out:
1405 	return ret;
1406 }
1407 EXPORT_SYMBOL_GPL(svc_alien_sock);
1408 
1409 /**
1410  * svc_addsock - add a listener socket to an RPC service
1411  * @serv: pointer to RPC service to which to add a new listener
1412  * @fd: file descriptor of the new listener
1413  * @name_return: pointer to buffer to fill in with name of listener
1414  * @len: size of the buffer
1415  *
1416  * Fills in socket name and returns positive length of name if successful.
1417  * Name is terminated with '\n'.  On error, returns a negative errno
1418  * value.
1419  */
1420 int svc_addsock(struct svc_serv *serv, const int fd, char *name_return,
1421 		const size_t len)
1422 {
1423 	int err = 0;
1424 	struct socket *so = sockfd_lookup(fd, &err);
1425 	struct svc_sock *svsk = NULL;
1426 	struct sockaddr_storage addr;
1427 	struct sockaddr *sin = (struct sockaddr *)&addr;
1428 	int salen;
1429 
1430 	if (!so)
1431 		return err;
1432 	err = -EAFNOSUPPORT;
1433 	if ((so->sk->sk_family != PF_INET) && (so->sk->sk_family != PF_INET6))
1434 		goto out;
1435 	err =  -EPROTONOSUPPORT;
1436 	if (so->sk->sk_protocol != IPPROTO_TCP &&
1437 	    so->sk->sk_protocol != IPPROTO_UDP)
1438 		goto out;
1439 	err = -EISCONN;
1440 	if (so->state > SS_UNCONNECTED)
1441 		goto out;
1442 	err = -ENOENT;
1443 	if (!try_module_get(THIS_MODULE))
1444 		goto out;
1445 	svsk = svc_setup_socket(serv, so, SVC_SOCK_DEFAULTS);
1446 	if (IS_ERR(svsk)) {
1447 		module_put(THIS_MODULE);
1448 		err = PTR_ERR(svsk);
1449 		goto out;
1450 	}
1451 	if (kernel_getsockname(svsk->sk_sock, sin, &salen) == 0)
1452 		svc_xprt_set_local(&svsk->sk_xprt, sin, salen);
1453 	svc_add_new_perm_xprt(serv, &svsk->sk_xprt);
1454 	return svc_one_sock_name(svsk, name_return, len);
1455 out:
1456 	sockfd_put(so);
1457 	return err;
1458 }
1459 EXPORT_SYMBOL_GPL(svc_addsock);
1460 
1461 /*
1462  * Create socket for RPC service.
1463  */
1464 static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
1465 					  int protocol,
1466 					  struct net *net,
1467 					  struct sockaddr *sin, int len,
1468 					  int flags)
1469 {
1470 	struct svc_sock	*svsk;
1471 	struct socket	*sock;
1472 	int		error;
1473 	int		type;
1474 	struct sockaddr_storage addr;
1475 	struct sockaddr *newsin = (struct sockaddr *)&addr;
1476 	int		newlen;
1477 	int		family;
1478 	int		val;
1479 	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
1480 
1481 	dprintk("svc: svc_create_socket(%s, %d, %s)\n",
1482 			serv->sv_program->pg_name, protocol,
1483 			__svc_print_addr(sin, buf, sizeof(buf)));
1484 
1485 	if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
1486 		printk(KERN_WARNING "svc: only UDP and TCP "
1487 				"sockets supported\n");
1488 		return ERR_PTR(-EINVAL);
1489 	}
1490 
1491 	type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
1492 	switch (sin->sa_family) {
1493 	case AF_INET6:
1494 		family = PF_INET6;
1495 		break;
1496 	case AF_INET:
1497 		family = PF_INET;
1498 		break;
1499 	default:
1500 		return ERR_PTR(-EINVAL);
1501 	}
1502 
1503 	error = __sock_create(net, family, type, protocol, &sock, 1);
1504 	if (error < 0)
1505 		return ERR_PTR(error);
1506 
1507 	svc_reclassify_socket(sock);
1508 
1509 	/*
1510 	 * If this is an PF_INET6 listener, we want to avoid
1511 	 * getting requests from IPv4 remotes.  Those should
1512 	 * be shunted to a PF_INET listener via rpcbind.
1513 	 */
1514 	val = 1;
1515 	if (family == PF_INET6)
1516 		kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
1517 					(char *)&val, sizeof(val));
1518 
1519 	if (type == SOCK_STREAM)
1520 		sock->sk->sk_reuse = SK_CAN_REUSE; /* allow address reuse */
1521 	error = kernel_bind(sock, sin, len);
1522 	if (error < 0)
1523 		goto bummer;
1524 
1525 	newlen = len;
1526 	error = kernel_getsockname(sock, newsin, &newlen);
1527 	if (error < 0)
1528 		goto bummer;
1529 
1530 	if (protocol == IPPROTO_TCP) {
1531 		if ((error = kernel_listen(sock, 64)) < 0)
1532 			goto bummer;
1533 	}
1534 
1535 	svsk = svc_setup_socket(serv, sock, flags);
1536 	if (IS_ERR(svsk)) {
1537 		error = PTR_ERR(svsk);
1538 		goto bummer;
1539 	}
1540 	svc_xprt_set_local(&svsk->sk_xprt, newsin, newlen);
1541 	return (struct svc_xprt *)svsk;
1542 bummer:
1543 	dprintk("svc: svc_create_socket error = %d\n", -error);
1544 	sock_release(sock);
1545 	return ERR_PTR(error);
1546 }
1547 
1548 /*
1549  * Detach the svc_sock from the socket so that no
1550  * more callbacks occur.
1551  */
1552 static void svc_sock_detach(struct svc_xprt *xprt)
1553 {
1554 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1555 	struct sock *sk = svsk->sk_sk;
1556 
1557 	dprintk("svc: svc_sock_detach(%p)\n", svsk);
1558 
1559 	/* put back the old socket callbacks */
1560 	lock_sock(sk);
1561 	sk->sk_state_change = svsk->sk_ostate;
1562 	sk->sk_data_ready = svsk->sk_odata;
1563 	sk->sk_write_space = svsk->sk_owspace;
1564 	sk->sk_user_data = NULL;
1565 	release_sock(sk);
1566 }
1567 
1568 /*
1569  * Disconnect the socket, and reset the callbacks
1570  */
1571 static void svc_tcp_sock_detach(struct svc_xprt *xprt)
1572 {
1573 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1574 
1575 	dprintk("svc: svc_tcp_sock_detach(%p)\n", svsk);
1576 
1577 	svc_sock_detach(xprt);
1578 
1579 	if (!test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
1580 		svc_tcp_clear_pages(svsk);
1581 		kernel_sock_shutdown(svsk->sk_sock, SHUT_RDWR);
1582 	}
1583 }
1584 
1585 /*
1586  * Free the svc_sock's socket resources and the svc_sock itself.
1587  */
1588 static void svc_sock_free(struct svc_xprt *xprt)
1589 {
1590 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1591 	dprintk("svc: svc_sock_free(%p)\n", svsk);
1592 
1593 	if (svsk->sk_sock->file)
1594 		sockfd_put(svsk->sk_sock);
1595 	else
1596 		sock_release(svsk->sk_sock);
1597 	kfree(svsk);
1598 }
1599 
1600 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1601 /*
1602  * Create a back channel svc_xprt which shares the fore channel socket.
1603  */
1604 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
1605 					     int protocol,
1606 					     struct net *net,
1607 					     struct sockaddr *sin, int len,
1608 					     int flags)
1609 {
1610 	struct svc_sock *svsk;
1611 	struct svc_xprt *xprt;
1612 
1613 	if (protocol != IPPROTO_TCP) {
1614 		printk(KERN_WARNING "svc: only TCP sockets"
1615 			" supported on shared back channel\n");
1616 		return ERR_PTR(-EINVAL);
1617 	}
1618 
1619 	svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
1620 	if (!svsk)
1621 		return ERR_PTR(-ENOMEM);
1622 
1623 	xprt = &svsk->sk_xprt;
1624 	svc_xprt_init(net, &svc_tcp_bc_class, xprt, serv);
1625 
1626 	serv->sv_bc_xprt = xprt;
1627 
1628 	return xprt;
1629 }
1630 
1631 /*
1632  * Free a back channel svc_sock.
1633  */
1634 static void svc_bc_sock_free(struct svc_xprt *xprt)
1635 {
1636 	if (xprt)
1637 		kfree(container_of(xprt, struct svc_sock, sk_xprt));
1638 }
1639 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1640