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Linux/net/sunrpc/svcsock.c

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  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 void             svc_udp_data_ready(struct sock *);
 64 static int              svc_udp_recvfrom(struct svc_rqst *);
 65 static int              svc_udp_sendto(struct svc_rqst *);
 66 static void             svc_sock_detach(struct svc_xprt *);
 67 static void             svc_tcp_sock_detach(struct svc_xprt *);
 68 static void             svc_sock_free(struct svc_xprt *);
 69 
 70 static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
 71                                           struct net *, struct sockaddr *,
 72                                           int, int);
 73 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 74 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
 75                                              struct net *, struct sockaddr *,
 76                                              int, int);
 77 static void svc_bc_sock_free(struct svc_xprt *xprt);
 78 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 79 
 80 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 81 static struct lock_class_key svc_key[2];
 82 static struct lock_class_key svc_slock_key[2];
 83 
 84 static void svc_reclassify_socket(struct socket *sock)
 85 {
 86         struct sock *sk = sock->sk;
 87 
 88         WARN_ON_ONCE(sock_owned_by_user(sk));
 89         if (sock_owned_by_user(sk))
 90                 return;
 91 
 92         switch (sk->sk_family) {
 93         case AF_INET:
 94                 sock_lock_init_class_and_name(sk, "slock-AF_INET-NFSD",
 95                                               &svc_slock_key[0],
 96                                               "sk_xprt.xpt_lock-AF_INET-NFSD",
 97                                               &svc_key[0]);
 98                 break;
 99 
100         case AF_INET6:
101                 sock_lock_init_class_and_name(sk, "slock-AF_INET6-NFSD",
102                                               &svc_slock_key[1],
103                                               "sk_xprt.xpt_lock-AF_INET6-NFSD",
104                                               &svc_key[1]);
105                 break;
106 
107         default:
108                 BUG();
109         }
110 }
111 #else
112 static void svc_reclassify_socket(struct socket *sock)
113 {
114 }
115 #endif
116 
117 /*
118  * Release an skbuff after use
119  */
120 static void svc_release_skb(struct svc_rqst *rqstp)
121 {
122         struct sk_buff *skb = rqstp->rq_xprt_ctxt;
123 
124         if (skb) {
125                 struct svc_sock *svsk =
126                         container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
127                 rqstp->rq_xprt_ctxt = NULL;
128 
129                 dprintk("svc: service %p, releasing skb %p\n", rqstp, skb);
130                 skb_free_datagram_locked(svsk->sk_sk, skb);
131         }
132 }
133 
134 union svc_pktinfo_u {
135         struct in_pktinfo pkti;
136         struct in6_pktinfo pkti6;
137 };
138 #define SVC_PKTINFO_SPACE \
139         CMSG_SPACE(sizeof(union svc_pktinfo_u))
140 
141 static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
142 {
143         struct svc_sock *svsk =
144                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
145         switch (svsk->sk_sk->sk_family) {
146         case AF_INET: {
147                         struct in_pktinfo *pki = CMSG_DATA(cmh);
148 
149                         cmh->cmsg_level = SOL_IP;
150                         cmh->cmsg_type = IP_PKTINFO;
151                         pki->ipi_ifindex = 0;
152                         pki->ipi_spec_dst.s_addr =
153                                  svc_daddr_in(rqstp)->sin_addr.s_addr;
154                         cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
155                 }
156                 break;
157 
158         case AF_INET6: {
159                         struct in6_pktinfo *pki = CMSG_DATA(cmh);
160                         struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
161 
162                         cmh->cmsg_level = SOL_IPV6;
163                         cmh->cmsg_type = IPV6_PKTINFO;
164                         pki->ipi6_ifindex = daddr->sin6_scope_id;
165                         pki->ipi6_addr = daddr->sin6_addr;
166                         cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
167                 }
168                 break;
169         }
170 }
171 
172 /*
173  * send routine intended to be shared by the fore- and back-channel
174  */
175 int svc_send_common(struct socket *sock, struct xdr_buf *xdr,
176                     struct page *headpage, unsigned long headoffset,
177                     struct page *tailpage, unsigned long tailoffset)
178 {
179         int             result;
180         int             size;
181         struct page     **ppage = xdr->pages;
182         size_t          base = xdr->page_base;
183         unsigned int    pglen = xdr->page_len;
184         unsigned int    flags = MSG_MORE | MSG_SENDPAGE_NOTLAST;
185         int             slen;
186         int             len = 0;
187 
188         slen = xdr->len;
189 
190         /* send head */
191         if (slen == xdr->head[0].iov_len)
192                 flags = 0;
193         len = kernel_sendpage(sock, headpage, headoffset,
194                                   xdr->head[0].iov_len, flags);
195         if (len != xdr->head[0].iov_len)
196                 goto out;
197         slen -= xdr->head[0].iov_len;
198         if (slen == 0)
199                 goto out;
200 
201         /* send page data */
202         size = PAGE_SIZE - base < pglen ? PAGE_SIZE - base : pglen;
203         while (pglen > 0) {
204                 if (slen == size)
205                         flags = 0;
206                 result = kernel_sendpage(sock, *ppage, base, size, flags);
207                 if (result > 0)
208                         len += result;
209                 if (result != size)
210                         goto out;
211                 slen -= size;
212                 pglen -= size;
213                 size = PAGE_SIZE < pglen ? PAGE_SIZE : pglen;
214                 base = 0;
215                 ppage++;
216         }
217 
218         /* send tail */
219         if (xdr->tail[0].iov_len) {
220                 result = kernel_sendpage(sock, tailpage, tailoffset,
221                                    xdr->tail[0].iov_len, 0);
222                 if (result > 0)
223                         len += result;
224         }
225 
226 out:
227         return len;
228 }
229 
230 
231 /*
232  * Generic sendto routine
233  */
234 static int svc_sendto(struct svc_rqst *rqstp, struct xdr_buf *xdr)
235 {
236         struct svc_sock *svsk =
237                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
238         struct socket   *sock = svsk->sk_sock;
239         union {
240                 struct cmsghdr  hdr;
241                 long            all[SVC_PKTINFO_SPACE / sizeof(long)];
242         } buffer;
243         struct cmsghdr *cmh = &buffer.hdr;
244         int             len = 0;
245         unsigned long tailoff;
246         unsigned long headoff;
247         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
248 
249         if (rqstp->rq_prot == IPPROTO_UDP) {
250                 struct msghdr msg = {
251                         .msg_name       = &rqstp->rq_addr,
252                         .msg_namelen    = rqstp->rq_addrlen,
253                         .msg_control    = cmh,
254                         .msg_controllen = sizeof(buffer),
255                         .msg_flags      = MSG_MORE,
256                 };
257 
258                 svc_set_cmsg_data(rqstp, cmh);
259 
260                 if (sock_sendmsg(sock, &msg) < 0)
261                         goto out;
262         }
263 
264         tailoff = ((unsigned long)xdr->tail[0].iov_base) & (PAGE_SIZE-1);
265         headoff = 0;
266         len = svc_send_common(sock, xdr, rqstp->rq_respages[0], headoff,
267                                rqstp->rq_respages[0], tailoff);
268 
269 out:
270         dprintk("svc: socket %p sendto([%p %Zu... ], %d) = %d (addr %s)\n",
271                 svsk, xdr->head[0].iov_base, xdr->head[0].iov_len,
272                 xdr->len, len, svc_print_addr(rqstp, buf, sizeof(buf)));
273 
274         return len;
275 }
276 
277 /*
278  * Report socket names for nfsdfs
279  */
280 static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
281 {
282         const struct sock *sk = svsk->sk_sk;
283         const char *proto_name = sk->sk_protocol == IPPROTO_UDP ?
284                                                         "udp" : "tcp";
285         int len;
286 
287         switch (sk->sk_family) {
288         case PF_INET:
289                 len = snprintf(buf, remaining, "ipv4 %s %pI4 %d\n",
290                                 proto_name,
291                                 &inet_sk(sk)->inet_rcv_saddr,
292                                 inet_sk(sk)->inet_num);
293                 break;
294 #if IS_ENABLED(CONFIG_IPV6)
295         case PF_INET6:
296                 len = snprintf(buf, remaining, "ipv6 %s %pI6 %d\n",
297                                 proto_name,
298                                 &sk->sk_v6_rcv_saddr,
299                                 inet_sk(sk)->inet_num);
300                 break;
301 #endif
302         default:
303                 len = snprintf(buf, remaining, "*unknown-%d*\n",
304                                 sk->sk_family);
305         }
306 
307         if (len >= remaining) {
308                 *buf = '\0';
309                 return -ENAMETOOLONG;
310         }
311         return len;
312 }
313 
314 /*
315  * Generic recvfrom routine.
316  */
317 static int svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov, int nr,
318                         int buflen)
319 {
320         struct svc_sock *svsk =
321                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
322         struct msghdr msg = {
323                 .msg_flags      = MSG_DONTWAIT,
324         };
325         int len;
326 
327         rqstp->rq_xprt_hlen = 0;
328 
329         clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
330         len = kernel_recvmsg(svsk->sk_sock, &msg, iov, nr, buflen,
331                                 msg.msg_flags);
332         /* If we read a full record, then assume there may be more
333          * data to read (stream based sockets only!)
334          */
335         if (len == buflen)
336                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
337 
338         dprintk("svc: socket %p recvfrom(%p, %Zu) = %d\n",
339                 svsk, iov[0].iov_base, iov[0].iov_len, len);
340         return len;
341 }
342 
343 static int svc_partial_recvfrom(struct svc_rqst *rqstp,
344                                 struct kvec *iov, int nr,
345                                 int buflen, unsigned int base)
346 {
347         size_t save_iovlen;
348         void *save_iovbase;
349         unsigned int i;
350         int ret;
351 
352         if (base == 0)
353                 return svc_recvfrom(rqstp, iov, nr, buflen);
354 
355         for (i = 0; i < nr; i++) {
356                 if (iov[i].iov_len > base)
357                         break;
358                 base -= iov[i].iov_len;
359         }
360         save_iovlen = iov[i].iov_len;
361         save_iovbase = iov[i].iov_base;
362         iov[i].iov_len -= base;
363         iov[i].iov_base += base;
364         ret = svc_recvfrom(rqstp, &iov[i], nr - i, buflen);
365         iov[i].iov_len = save_iovlen;
366         iov[i].iov_base = save_iovbase;
367         return ret;
368 }
369 
370 /*
371  * Set socket snd and rcv buffer lengths
372  */
373 static void svc_sock_setbufsize(struct socket *sock, unsigned int snd,
374                                 unsigned int rcv)
375 {
376 #if 0
377         mm_segment_t    oldfs;
378         oldfs = get_fs(); set_fs(KERNEL_DS);
379         sock_setsockopt(sock, SOL_SOCKET, SO_SNDBUF,
380                         (char*)&snd, sizeof(snd));
381         sock_setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
382                         (char*)&rcv, sizeof(rcv));
383 #else
384         /* sock_setsockopt limits use to sysctl_?mem_max,
385          * which isn't acceptable.  Until that is made conditional
386          * on not having CAP_SYS_RESOURCE or similar, we go direct...
387          * DaveM said I could!
388          */
389         lock_sock(sock->sk);
390         sock->sk->sk_sndbuf = snd * 2;
391         sock->sk->sk_rcvbuf = rcv * 2;
392         sock->sk->sk_write_space(sock->sk);
393         release_sock(sock->sk);
394 #endif
395 }
396 
397 static int svc_sock_secure_port(struct svc_rqst *rqstp)
398 {
399         return svc_port_is_privileged(svc_addr(rqstp));
400 }
401 
402 static bool sunrpc_waitqueue_active(wait_queue_head_t *wq)
403 {
404         if (!wq)
405                 return false;
406         /*
407          * There should normally be a memory * barrier here--see
408          * wq_has_sleeper().
409          *
410          * It appears that isn't currently necessary, though, basically
411          * because callers all appear to have sufficient memory barriers
412          * between the time the relevant change is made and the
413          * time they call these callbacks.
414          *
415          * The nfsd code itself doesn't actually explicitly wait on
416          * these waitqueues, but it may wait on them for example in
417          * sendpage() or sendmsg() calls.  (And those may be the only
418          * places, since it it uses nonblocking reads.)
419          *
420          * Maybe we should add the memory barriers anyway, but these are
421          * hot paths so we'd need to be convinced there's no sigificant
422          * penalty.
423          */
424         return waitqueue_active(wq);
425 }
426 
427 /*
428  * INET callback when data has been received on the socket.
429  */
430 static void svc_udp_data_ready(struct sock *sk)
431 {
432         struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
433         wait_queue_head_t *wq = sk_sleep(sk);
434 
435         if (svsk) {
436                 dprintk("svc: socket %p(inet %p), busy=%d\n",
437                         svsk, sk,
438                         test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
439                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
440                 svc_xprt_enqueue(&svsk->sk_xprt);
441         }
442         if (sunrpc_waitqueue_active(wq))
443                 wake_up_interruptible(wq);
444 }
445 
446 /*
447  * INET callback when space is newly available on the socket.
448  */
449 static void svc_write_space(struct sock *sk)
450 {
451         struct svc_sock *svsk = (struct svc_sock *)(sk->sk_user_data);
452         wait_queue_head_t *wq = sk_sleep(sk);
453 
454         if (svsk) {
455                 dprintk("svc: socket %p(inet %p), write_space busy=%d\n",
456                         svsk, sk, test_bit(XPT_BUSY, &svsk->sk_xprt.xpt_flags));
457                 svc_xprt_enqueue(&svsk->sk_xprt);
458         }
459 
460         if (sunrpc_waitqueue_active(wq)) {
461                 dprintk("RPC svc_write_space: someone sleeping on %p\n",
462                        svsk);
463                 wake_up_interruptible(wq);
464         }
465 }
466 
467 static int svc_tcp_has_wspace(struct svc_xprt *xprt)
468 {
469         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
470         struct svc_serv *serv = svsk->sk_xprt.xpt_server;
471         int required;
472 
473         if (test_bit(XPT_LISTENER, &xprt->xpt_flags))
474                 return 1;
475         required = atomic_read(&xprt->xpt_reserved) + serv->sv_max_mesg;
476         if (sk_stream_wspace(svsk->sk_sk) >= required ||
477             (sk_stream_min_wspace(svsk->sk_sk) == 0 &&
478              atomic_read(&xprt->xpt_reserved) == 0))
479                 return 1;
480         set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
481         return 0;
482 }
483 
484 static void svc_tcp_write_space(struct sock *sk)
485 {
486         struct svc_sock *svsk = (struct svc_sock *)(sk->sk_user_data);
487         struct socket *sock = sk->sk_socket;
488 
489         if (!sk_stream_is_writeable(sk) || !sock)
490                 return;
491         if (!svsk || svc_tcp_has_wspace(&svsk->sk_xprt))
492                 clear_bit(SOCK_NOSPACE, &sock->flags);
493         svc_write_space(sk);
494 }
495 
496 static void svc_tcp_adjust_wspace(struct svc_xprt *xprt)
497 {
498         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
499 
500         if (svc_tcp_has_wspace(xprt))
501                 clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
502 }
503 
504 /*
505  * See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
506  */
507 static int svc_udp_get_dest_address4(struct svc_rqst *rqstp,
508                                      struct cmsghdr *cmh)
509 {
510         struct in_pktinfo *pki = CMSG_DATA(cmh);
511         struct sockaddr_in *daddr = svc_daddr_in(rqstp);
512 
513         if (cmh->cmsg_type != IP_PKTINFO)
514                 return 0;
515 
516         daddr->sin_family = AF_INET;
517         daddr->sin_addr.s_addr = pki->ipi_spec_dst.s_addr;
518         return 1;
519 }
520 
521 /*
522  * See net/ipv6/datagram.c : ip6_datagram_recv_ctl
523  */
524 static int svc_udp_get_dest_address6(struct svc_rqst *rqstp,
525                                      struct cmsghdr *cmh)
526 {
527         struct in6_pktinfo *pki = CMSG_DATA(cmh);
528         struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
529 
530         if (cmh->cmsg_type != IPV6_PKTINFO)
531                 return 0;
532 
533         daddr->sin6_family = AF_INET6;
534         daddr->sin6_addr = pki->ipi6_addr;
535         daddr->sin6_scope_id = pki->ipi6_ifindex;
536         return 1;
537 }
538 
539 /*
540  * Copy the UDP datagram's destination address to the rqstp structure.
541  * The 'destination' address in this case is the address to which the
542  * peer sent the datagram, i.e. our local address. For multihomed
543  * hosts, this can change from msg to msg. Note that only the IP
544  * address changes, the port number should remain the same.
545  */
546 static int svc_udp_get_dest_address(struct svc_rqst *rqstp,
547                                     struct cmsghdr *cmh)
548 {
549         switch (cmh->cmsg_level) {
550         case SOL_IP:
551                 return svc_udp_get_dest_address4(rqstp, cmh);
552         case SOL_IPV6:
553                 return svc_udp_get_dest_address6(rqstp, cmh);
554         }
555 
556         return 0;
557 }
558 
559 /*
560  * Receive a datagram from a UDP socket.
561  */
562 static int svc_udp_recvfrom(struct svc_rqst *rqstp)
563 {
564         struct svc_sock *svsk =
565                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
566         struct svc_serv *serv = svsk->sk_xprt.xpt_server;
567         struct sk_buff  *skb;
568         union {
569                 struct cmsghdr  hdr;
570                 long            all[SVC_PKTINFO_SPACE / sizeof(long)];
571         } buffer;
572         struct cmsghdr *cmh = &buffer.hdr;
573         struct msghdr msg = {
574                 .msg_name = svc_addr(rqstp),
575                 .msg_control = cmh,
576                 .msg_controllen = sizeof(buffer),
577                 .msg_flags = MSG_DONTWAIT,
578         };
579         size_t len;
580         int err;
581 
582         if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
583             /* udp sockets need large rcvbuf as all pending
584              * requests are still in that buffer.  sndbuf must
585              * also be large enough that there is enough space
586              * for one reply per thread.  We count all threads
587              * rather than threads in a particular pool, which
588              * provides an upper bound on the number of threads
589              * which will access the socket.
590              */
591             svc_sock_setbufsize(svsk->sk_sock,
592                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg,
593                                 (serv->sv_nrthreads+3) * serv->sv_max_mesg);
594 
595         clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
596         skb = NULL;
597         err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
598                              0, 0, MSG_PEEK | MSG_DONTWAIT);
599         if (err >= 0)
600                 skb = skb_recv_datagram(svsk->sk_sk, 0, 1, &err);
601 
602         if (skb == NULL) {
603                 if (err != -EAGAIN) {
604                         /* possibly an icmp error */
605                         dprintk("svc: recvfrom returned error %d\n", -err);
606                         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
607                 }
608                 return 0;
609         }
610         len = svc_addr_len(svc_addr(rqstp));
611         rqstp->rq_addrlen = len;
612         if (skb->tstamp.tv64 == 0) {
613                 skb->tstamp = ktime_get_real();
614                 /* Don't enable netstamp, sunrpc doesn't
615                    need that much accuracy */
616         }
617         svsk->sk_sk->sk_stamp = skb->tstamp;
618         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
619 
620         len  = skb->len - sizeof(struct udphdr);
621         rqstp->rq_arg.len = len;
622 
623         rqstp->rq_prot = IPPROTO_UDP;
624 
625         if (!svc_udp_get_dest_address(rqstp, cmh)) {
626                 net_warn_ratelimited("svc: received unknown control message %d/%d; dropping RPC reply datagram\n",
627                                      cmh->cmsg_level, cmh->cmsg_type);
628                 goto out_free;
629         }
630         rqstp->rq_daddrlen = svc_addr_len(svc_daddr(rqstp));
631 
632         if (skb_is_nonlinear(skb)) {
633                 /* we have to copy */
634                 local_bh_disable();
635                 if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
636                         local_bh_enable();
637                         /* checksum error */
638                         goto out_free;
639                 }
640                 local_bh_enable();
641                 skb_free_datagram_locked(svsk->sk_sk, skb);
642         } else {
643                 /* we can use it in-place */
644                 rqstp->rq_arg.head[0].iov_base = skb->data +
645                         sizeof(struct udphdr);
646                 rqstp->rq_arg.head[0].iov_len = len;
647                 if (skb_checksum_complete(skb))
648                         goto out_free;
649                 rqstp->rq_xprt_ctxt = skb;
650         }
651 
652         rqstp->rq_arg.page_base = 0;
653         if (len <= rqstp->rq_arg.head[0].iov_len) {
654                 rqstp->rq_arg.head[0].iov_len = len;
655                 rqstp->rq_arg.page_len = 0;
656                 rqstp->rq_respages = rqstp->rq_pages+1;
657         } else {
658                 rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
659                 rqstp->rq_respages = rqstp->rq_pages + 1 +
660                         DIV_ROUND_UP(rqstp->rq_arg.page_len, PAGE_SIZE);
661         }
662         rqstp->rq_next_page = rqstp->rq_respages+1;
663 
664         if (serv->sv_stats)
665                 serv->sv_stats->netudpcnt++;
666 
667         return len;
668 out_free:
669         trace_kfree_skb(skb, svc_udp_recvfrom);
670         skb_free_datagram_locked(svsk->sk_sk, skb);
671         return 0;
672 }
673 
674 static int
675 svc_udp_sendto(struct svc_rqst *rqstp)
676 {
677         int             error;
678 
679         error = svc_sendto(rqstp, &rqstp->rq_res);
680         if (error == -ECONNREFUSED)
681                 /* ICMP error on earlier request. */
682                 error = svc_sendto(rqstp, &rqstp->rq_res);
683 
684         return error;
685 }
686 
687 static void svc_udp_prep_reply_hdr(struct svc_rqst *rqstp)
688 {
689 }
690 
691 static int svc_udp_has_wspace(struct svc_xprt *xprt)
692 {
693         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
694         struct svc_serv *serv = xprt->xpt_server;
695         unsigned long required;
696 
697         /*
698          * Set the SOCK_NOSPACE flag before checking the available
699          * sock space.
700          */
701         set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
702         required = atomic_read(&svsk->sk_xprt.xpt_reserved) + serv->sv_max_mesg;
703         if (required*2 > sock_wspace(svsk->sk_sk))
704                 return 0;
705         clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
706         return 1;
707 }
708 
709 static struct svc_xprt *svc_udp_accept(struct svc_xprt *xprt)
710 {
711         BUG();
712         return NULL;
713 }
714 
715 static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
716                                        struct net *net,
717                                        struct sockaddr *sa, int salen,
718                                        int flags)
719 {
720         return svc_create_socket(serv, IPPROTO_UDP, net, sa, salen, flags);
721 }
722 
723 static struct svc_xprt_ops svc_udp_ops = {
724         .xpo_create = svc_udp_create,
725         .xpo_recvfrom = svc_udp_recvfrom,
726         .xpo_sendto = svc_udp_sendto,
727         .xpo_release_rqst = svc_release_skb,
728         .xpo_detach = svc_sock_detach,
729         .xpo_free = svc_sock_free,
730         .xpo_prep_reply_hdr = svc_udp_prep_reply_hdr,
731         .xpo_has_wspace = svc_udp_has_wspace,
732         .xpo_accept = svc_udp_accept,
733         .xpo_secure_port = svc_sock_secure_port,
734 };
735 
736 static struct svc_xprt_class svc_udp_class = {
737         .xcl_name = "udp",
738         .xcl_owner = THIS_MODULE,
739         .xcl_ops = &svc_udp_ops,
740         .xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
741         .xcl_ident = XPRT_TRANSPORT_UDP,
742 };
743 
744 static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
745 {
746         int err, level, optname, one = 1;
747 
748         svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
749                       &svsk->sk_xprt, serv);
750         clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
751         svsk->sk_sk->sk_data_ready = svc_udp_data_ready;
752         svsk->sk_sk->sk_write_space = svc_write_space;
753 
754         /* initialise setting must have enough space to
755          * receive and respond to one request.
756          * svc_udp_recvfrom will re-adjust if necessary
757          */
758         svc_sock_setbufsize(svsk->sk_sock,
759                             3 * svsk->sk_xprt.xpt_server->sv_max_mesg,
760                             3 * svsk->sk_xprt.xpt_server->sv_max_mesg);
761 
762         /* data might have come in before data_ready set up */
763         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
764         set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
765 
766         /* make sure we get destination address info */
767         switch (svsk->sk_sk->sk_family) {
768         case AF_INET:
769                 level = SOL_IP;
770                 optname = IP_PKTINFO;
771                 break;
772         case AF_INET6:
773                 level = SOL_IPV6;
774                 optname = IPV6_RECVPKTINFO;
775                 break;
776         default:
777                 BUG();
778         }
779         err = kernel_setsockopt(svsk->sk_sock, level, optname,
780                                         (char *)&one, sizeof(one));
781         dprintk("svc: kernel_setsockopt returned %d\n", err);
782 }
783 
784 /*
785  * A data_ready event on a listening socket means there's a connection
786  * pending. Do not use state_change as a substitute for it.
787  */
788 static void svc_tcp_listen_data_ready(struct sock *sk)
789 {
790         struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
791         wait_queue_head_t *wq;
792 
793         dprintk("svc: socket %p TCP (listen) state change %d\n",
794                 sk, sk->sk_state);
795 
796         /*
797          * This callback may called twice when a new connection
798          * is established as a child socket inherits everything
799          * from a parent LISTEN socket.
800          * 1) data_ready method of the parent socket will be called
801          *    when one of child sockets become ESTABLISHED.
802          * 2) data_ready method of the child socket may be called
803          *    when it receives data before the socket is accepted.
804          * In case of 2, we should ignore it silently.
805          */
806         if (sk->sk_state == TCP_LISTEN) {
807                 if (svsk) {
808                         set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
809                         svc_xprt_enqueue(&svsk->sk_xprt);
810                 } else
811                         printk("svc: socket %p: no user data\n", sk);
812         }
813 
814         wq = sk_sleep(sk);
815         if (sunrpc_waitqueue_active(wq))
816                 wake_up_interruptible_all(wq);
817 }
818 
819 /*
820  * A state change on a connected socket means it's dying or dead.
821  */
822 static void svc_tcp_state_change(struct sock *sk)
823 {
824         struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
825         wait_queue_head_t *wq = sk_sleep(sk);
826 
827         dprintk("svc: socket %p TCP (connected) state change %d (svsk %p)\n",
828                 sk, sk->sk_state, sk->sk_user_data);
829 
830         if (!svsk)
831                 printk("svc: socket %p: no user data\n", sk);
832         else {
833                 set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
834                 svc_xprt_enqueue(&svsk->sk_xprt);
835         }
836         if (sunrpc_waitqueue_active(wq))
837                 wake_up_interruptible_all(wq);
838 }
839 
840 static void svc_tcp_data_ready(struct sock *sk)
841 {
842         struct svc_sock *svsk = (struct svc_sock *)sk->sk_user_data;
843         wait_queue_head_t *wq = sk_sleep(sk);
844 
845         dprintk("svc: socket %p TCP data ready (svsk %p)\n",
846                 sk, sk->sk_user_data);
847         if (svsk) {
848                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
849                 svc_xprt_enqueue(&svsk->sk_xprt);
850         }
851         if (sunrpc_waitqueue_active(wq))
852                 wake_up_interruptible(wq);
853 }
854 
855 /*
856  * Accept a TCP connection
857  */
858 static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
859 {
860         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
861         struct sockaddr_storage addr;
862         struct sockaddr *sin = (struct sockaddr *) &addr;
863         struct svc_serv *serv = svsk->sk_xprt.xpt_server;
864         struct socket   *sock = svsk->sk_sock;
865         struct socket   *newsock;
866         struct svc_sock *newsvsk;
867         int             err, slen;
868         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
869 
870         dprintk("svc: tcp_accept %p sock %p\n", svsk, sock);
871         if (!sock)
872                 return NULL;
873 
874         clear_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
875         err = kernel_accept(sock, &newsock, O_NONBLOCK);
876         if (err < 0) {
877                 if (err == -ENOMEM)
878                         printk(KERN_WARNING "%s: no more sockets!\n",
879                                serv->sv_name);
880                 else if (err != -EAGAIN)
881                         net_warn_ratelimited("%s: accept failed (err %d)!\n",
882                                              serv->sv_name, -err);
883                 return NULL;
884         }
885         set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
886 
887         err = kernel_getpeername(newsock, sin, &slen);
888         if (err < 0) {
889                 net_warn_ratelimited("%s: peername failed (err %d)!\n",
890                                      serv->sv_name, -err);
891                 goto failed;            /* aborted connection or whatever */
892         }
893 
894         /* Ideally, we would want to reject connections from unauthorized
895          * hosts here, but when we get encryption, the IP of the host won't
896          * tell us anything.  For now just warn about unpriv connections.
897          */
898         if (!svc_port_is_privileged(sin)) {
899                 dprintk("%s: connect from unprivileged port: %s\n",
900                         serv->sv_name,
901                         __svc_print_addr(sin, buf, sizeof(buf)));
902         }
903         dprintk("%s: connect from %s\n", serv->sv_name,
904                 __svc_print_addr(sin, buf, sizeof(buf)));
905 
906         /* make sure that a write doesn't block forever when
907          * low on memory
908          */
909         newsock->sk->sk_sndtimeo = HZ*30;
910 
911         newsvsk = svc_setup_socket(serv, newsock,
912                                  (SVC_SOCK_ANONYMOUS | SVC_SOCK_TEMPORARY));
913         if (IS_ERR(newsvsk))
914                 goto failed;
915         svc_xprt_set_remote(&newsvsk->sk_xprt, sin, slen);
916         err = kernel_getsockname(newsock, sin, &slen);
917         if (unlikely(err < 0)) {
918                 dprintk("svc_tcp_accept: kernel_getsockname error %d\n", -err);
919                 slen = offsetof(struct sockaddr, sa_data);
920         }
921         svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
922 
923         if (sock_is_loopback(newsock->sk))
924                 set_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
925         else
926                 clear_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
927         if (serv->sv_stats)
928                 serv->sv_stats->nettcpconn++;
929 
930         return &newsvsk->sk_xprt;
931 
932 failed:
933         sock_release(newsock);
934         return NULL;
935 }
936 
937 static unsigned int svc_tcp_restore_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
938 {
939         unsigned int i, len, npages;
940 
941         if (svsk->sk_datalen == 0)
942                 return 0;
943         len = svsk->sk_datalen;
944         npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
945         for (i = 0; i < npages; i++) {
946                 if (rqstp->rq_pages[i] != NULL)
947                         put_page(rqstp->rq_pages[i]);
948                 BUG_ON(svsk->sk_pages[i] == NULL);
949                 rqstp->rq_pages[i] = svsk->sk_pages[i];
950                 svsk->sk_pages[i] = NULL;
951         }
952         rqstp->rq_arg.head[0].iov_base = page_address(rqstp->rq_pages[0]);
953         return len;
954 }
955 
956 static void svc_tcp_save_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
957 {
958         unsigned int i, len, npages;
959 
960         if (svsk->sk_datalen == 0)
961                 return;
962         len = svsk->sk_datalen;
963         npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
964         for (i = 0; i < npages; i++) {
965                 svsk->sk_pages[i] = rqstp->rq_pages[i];
966                 rqstp->rq_pages[i] = NULL;
967         }
968 }
969 
970 static void svc_tcp_clear_pages(struct svc_sock *svsk)
971 {
972         unsigned int i, len, npages;
973 
974         if (svsk->sk_datalen == 0)
975                 goto out;
976         len = svsk->sk_datalen;
977         npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
978         for (i = 0; i < npages; i++) {
979                 if (svsk->sk_pages[i] == NULL) {
980                         WARN_ON_ONCE(1);
981                         continue;
982                 }
983                 put_page(svsk->sk_pages[i]);
984                 svsk->sk_pages[i] = NULL;
985         }
986 out:
987         svsk->sk_tcplen = 0;
988         svsk->sk_datalen = 0;
989 }
990 
991 /*
992  * Receive fragment record header.
993  * If we haven't gotten the record length yet, get the next four bytes.
994  */
995 static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
996 {
997         struct svc_serv *serv = svsk->sk_xprt.xpt_server;
998         unsigned int want;
999         int len;
1000 
1001         if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
1002                 struct kvec     iov;
1003 
1004                 want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
1005                 iov.iov_base = ((char *) &svsk->sk_reclen) + svsk->sk_tcplen;
1006                 iov.iov_len  = want;
1007                 if ((len = svc_recvfrom(rqstp, &iov, 1, want)) < 0)
1008                         goto error;
1009                 svsk->sk_tcplen += len;
1010 
1011                 if (len < want) {
1012                         dprintk("svc: short recvfrom while reading record "
1013                                 "length (%d of %d)\n", len, want);
1014                         return -EAGAIN;
1015                 }
1016 
1017                 dprintk("svc: TCP record, %d bytes\n", svc_sock_reclen(svsk));
1018                 if (svc_sock_reclen(svsk) + svsk->sk_datalen >
1019                                                         serv->sv_max_mesg) {
1020                         net_notice_ratelimited("RPC: fragment too large: %d\n",
1021                                         svc_sock_reclen(svsk));
1022                         goto err_delete;
1023                 }
1024         }
1025 
1026         return svc_sock_reclen(svsk);
1027 error:
1028         dprintk("RPC: TCP recv_record got %d\n", len);
1029         return len;
1030 err_delete:
1031         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
1032         return -EAGAIN;
1033 }
1034 
1035 static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
1036 {
1037         struct rpc_xprt *bc_xprt = svsk->sk_xprt.xpt_bc_xprt;
1038         struct rpc_rqst *req = NULL;
1039         struct kvec *src, *dst;
1040         __be32 *p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
1041         __be32 xid;
1042         __be32 calldir;
1043 
1044         xid = *p++;
1045         calldir = *p;
1046 
1047         if (!bc_xprt)
1048                 return -EAGAIN;
1049         spin_lock_bh(&bc_xprt->transport_lock);
1050         req = xprt_lookup_rqst(bc_xprt, xid);
1051         if (!req)
1052                 goto unlock_notfound;
1053 
1054         memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
1055         /*
1056          * XXX!: cheating for now!  Only copying HEAD.
1057          * But we know this is good enough for now (in fact, for any
1058          * callback reply in the forseeable future).
1059          */
1060         dst = &req->rq_private_buf.head[0];
1061         src = &rqstp->rq_arg.head[0];
1062         if (dst->iov_len < src->iov_len)
1063                 goto unlock_eagain; /* whatever; just giving up. */
1064         memcpy(dst->iov_base, src->iov_base, src->iov_len);
1065         xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len);
1066         rqstp->rq_arg.len = 0;
1067         spin_unlock_bh(&bc_xprt->transport_lock);
1068         return 0;
1069 unlock_notfound:
1070         printk(KERN_NOTICE
1071                 "%s: Got unrecognized reply: "
1072                 "calldir 0x%x xpt_bc_xprt %p xid %08x\n",
1073                 __func__, ntohl(calldir),
1074                 bc_xprt, ntohl(xid));
1075 unlock_eagain:
1076         spin_unlock_bh(&bc_xprt->transport_lock);
1077         return -EAGAIN;
1078 }
1079 
1080 static int copy_pages_to_kvecs(struct kvec *vec, struct page **pages, int len)
1081 {
1082         int i = 0;
1083         int t = 0;
1084 
1085         while (t < len) {
1086                 vec[i].iov_base = page_address(pages[i]);
1087                 vec[i].iov_len = PAGE_SIZE;
1088                 i++;
1089                 t += PAGE_SIZE;
1090         }
1091         return i;
1092 }
1093 
1094 static void svc_tcp_fragment_received(struct svc_sock *svsk)
1095 {
1096         /* If we have more data, signal svc_xprt_enqueue() to try again */
1097         dprintk("svc: TCP %s record (%d bytes)\n",
1098                 svc_sock_final_rec(svsk) ? "final" : "nonfinal",
1099                 svc_sock_reclen(svsk));
1100         svsk->sk_tcplen = 0;
1101         svsk->sk_reclen = 0;
1102 }
1103 
1104 /*
1105  * Receive data from a TCP socket.
1106  */
1107 static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
1108 {
1109         struct svc_sock *svsk =
1110                 container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
1111         struct svc_serv *serv = svsk->sk_xprt.xpt_server;
1112         int             len;
1113         struct kvec *vec;
1114         unsigned int want, base;
1115         __be32 *p;
1116         __be32 calldir;
1117         int pnum;
1118 
1119         dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
1120                 svsk, test_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags),
1121                 test_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags),
1122                 test_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags));
1123 
1124         len = svc_tcp_recv_record(svsk, rqstp);
1125         if (len < 0)
1126                 goto error;
1127 
1128         base = svc_tcp_restore_pages(svsk, rqstp);
1129         want = svc_sock_reclen(svsk) - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
1130 
1131         vec = rqstp->rq_vec;
1132 
1133         pnum = copy_pages_to_kvecs(&vec[0], &rqstp->rq_pages[0],
1134                                                 svsk->sk_datalen + want);
1135 
1136         rqstp->rq_respages = &rqstp->rq_pages[pnum];
1137         rqstp->rq_next_page = rqstp->rq_respages + 1;
1138 
1139         /* Now receive data */
1140         len = svc_partial_recvfrom(rqstp, vec, pnum, want, base);
1141         if (len >= 0) {
1142                 svsk->sk_tcplen += len;
1143                 svsk->sk_datalen += len;
1144         }
1145         if (len != want || !svc_sock_final_rec(svsk)) {
1146                 svc_tcp_save_pages(svsk, rqstp);
1147                 if (len < 0 && len != -EAGAIN)
1148                         goto err_delete;
1149                 if (len == want)
1150                         svc_tcp_fragment_received(svsk);
1151                 else
1152                         dprintk("svc: incomplete TCP record (%d of %d)\n",
1153                                 (int)(svsk->sk_tcplen - sizeof(rpc_fraghdr)),
1154                                 svc_sock_reclen(svsk));
1155                 goto err_noclose;
1156         }
1157 
1158         if (svsk->sk_datalen < 8) {
1159                 svsk->sk_datalen = 0;
1160                 goto err_delete; /* client is nuts. */
1161         }
1162 
1163         rqstp->rq_arg.len = svsk->sk_datalen;
1164         rqstp->rq_arg.page_base = 0;
1165         if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
1166                 rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
1167                 rqstp->rq_arg.page_len = 0;
1168         } else
1169                 rqstp->rq_arg.page_len = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1170 
1171         rqstp->rq_xprt_ctxt   = NULL;
1172         rqstp->rq_prot        = IPPROTO_TCP;
1173         if (test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags))
1174                 set_bit(RQ_LOCAL, &rqstp->rq_flags);
1175         else
1176                 clear_bit(RQ_LOCAL, &rqstp->rq_flags);
1177 
1178         p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
1179         calldir = p[1];
1180         if (calldir)
1181                 len = receive_cb_reply(svsk, rqstp);
1182 
1183         /* Reset TCP read info */
1184         svsk->sk_datalen = 0;
1185         svc_tcp_fragment_received(svsk);
1186 
1187         if (len < 0)
1188                 goto error;
1189 
1190         svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt);
1191         if (serv->sv_stats)
1192                 serv->sv_stats->nettcpcnt++;
1193 
1194         return rqstp->rq_arg.len;
1195 
1196 error:
1197         if (len != -EAGAIN)
1198                 goto err_delete;
1199         dprintk("RPC: TCP recvfrom got EAGAIN\n");
1200         return 0;
1201 err_delete:
1202         printk(KERN_NOTICE "%s: recvfrom returned errno %d\n",
1203                svsk->sk_xprt.xpt_server->sv_name, -len);
1204         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
1205 err_noclose:
1206         return 0;       /* record not complete */
1207 }
1208 
1209 /*
1210  * Send out data on TCP socket.
1211  */
1212 static int svc_tcp_sendto(struct svc_rqst *rqstp)
1213 {
1214         struct xdr_buf  *xbufp = &rqstp->rq_res;
1215         int sent;
1216         __be32 reclen;
1217 
1218         /* Set up the first element of the reply kvec.
1219          * Any other kvecs that may be in use have been taken
1220          * care of by the server implementation itself.
1221          */
1222         reclen = htonl(0x80000000|((xbufp->len ) - 4));
1223         memcpy(xbufp->head[0].iov_base, &reclen, 4);
1224 
1225         sent = svc_sendto(rqstp, &rqstp->rq_res);
1226         if (sent != xbufp->len) {
1227                 printk(KERN_NOTICE
1228                        "rpc-srv/tcp: %s: %s %d when sending %d bytes "
1229                        "- shutting down socket\n",
1230                        rqstp->rq_xprt->xpt_server->sv_name,
1231                        (sent<0)?"got error":"sent only",
1232                        sent, xbufp->len);
1233                 set_bit(XPT_CLOSE, &rqstp->rq_xprt->xpt_flags);
1234                 svc_xprt_enqueue(rqstp->rq_xprt);
1235                 sent = -EAGAIN;
1236         }
1237         return sent;
1238 }
1239 
1240 /*
1241  * Setup response header. TCP has a 4B record length field.
1242  */
1243 static void svc_tcp_prep_reply_hdr(struct svc_rqst *rqstp)
1244 {
1245         struct kvec *resv = &rqstp->rq_res.head[0];
1246 
1247         /* tcp needs a space for the record length... */
1248         svc_putnl(resv, 0);
1249 }
1250 
1251 static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
1252                                        struct net *net,
1253                                        struct sockaddr *sa, int salen,
1254                                        int flags)
1255 {
1256         return svc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
1257 }
1258 
1259 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1260 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *, int,
1261                                              struct net *, struct sockaddr *,
1262                                              int, int);
1263 static void svc_bc_sock_free(struct svc_xprt *xprt);
1264 
1265 static struct svc_xprt *svc_bc_tcp_create(struct svc_serv *serv,
1266                                        struct net *net,
1267                                        struct sockaddr *sa, int salen,
1268                                        int flags)
1269 {
1270         return svc_bc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
1271 }
1272 
1273 static void svc_bc_tcp_sock_detach(struct svc_xprt *xprt)
1274 {
1275 }
1276 
1277 static struct svc_xprt_ops svc_tcp_bc_ops = {
1278         .xpo_create = svc_bc_tcp_create,
1279         .xpo_detach = svc_bc_tcp_sock_detach,
1280         .xpo_free = svc_bc_sock_free,
1281         .xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
1282         .xpo_secure_port = svc_sock_secure_port,
1283 };
1284 
1285 static struct svc_xprt_class svc_tcp_bc_class = {
1286         .xcl_name = "tcp-bc",
1287         .xcl_owner = THIS_MODULE,
1288         .xcl_ops = &svc_tcp_bc_ops,
1289         .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
1290 };
1291 
1292 static void svc_init_bc_xprt_sock(void)
1293 {
1294         svc_reg_xprt_class(&svc_tcp_bc_class);
1295 }
1296 
1297 static void svc_cleanup_bc_xprt_sock(void)
1298 {
1299         svc_unreg_xprt_class(&svc_tcp_bc_class);
1300 }
1301 #else /* CONFIG_SUNRPC_BACKCHANNEL */
1302 static void svc_init_bc_xprt_sock(void)
1303 {
1304 }
1305 
1306 static void svc_cleanup_bc_xprt_sock(void)
1307 {
1308 }
1309 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1310 
1311 static struct svc_xprt_ops svc_tcp_ops = {
1312         .xpo_create = svc_tcp_create,
1313         .xpo_recvfrom = svc_tcp_recvfrom,
1314         .xpo_sendto = svc_tcp_sendto,
1315         .xpo_release_rqst = svc_release_skb,
1316         .xpo_detach = svc_tcp_sock_detach,
1317         .xpo_free = svc_sock_free,
1318         .xpo_prep_reply_hdr = svc_tcp_prep_reply_hdr,
1319         .xpo_has_wspace = svc_tcp_has_wspace,
1320         .xpo_accept = svc_tcp_accept,
1321         .xpo_secure_port = svc_sock_secure_port,
1322         .xpo_adjust_wspace = svc_tcp_adjust_wspace,
1323 };
1324 
1325 static struct svc_xprt_class svc_tcp_class = {
1326         .xcl_name = "tcp",
1327         .xcl_owner = THIS_MODULE,
1328         .xcl_ops = &svc_tcp_ops,
1329         .xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
1330         .xcl_ident = XPRT_TRANSPORT_TCP,
1331 };
1332 
1333 void svc_init_xprt_sock(void)
1334 {
1335         svc_reg_xprt_class(&svc_tcp_class);
1336         svc_reg_xprt_class(&svc_udp_class);
1337         svc_init_bc_xprt_sock();
1338 }
1339 
1340 void svc_cleanup_xprt_sock(void)
1341 {
1342         svc_unreg_xprt_class(&svc_tcp_class);
1343         svc_unreg_xprt_class(&svc_udp_class);
1344         svc_cleanup_bc_xprt_sock();
1345 }
1346 
1347 static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
1348 {
1349         struct sock     *sk = svsk->sk_sk;
1350 
1351         svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_tcp_class,
1352                       &svsk->sk_xprt, serv);
1353         set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
1354         if (sk->sk_state == TCP_LISTEN) {
1355                 dprintk("setting up TCP socket for listening\n");
1356                 set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
1357                 sk->sk_data_ready = svc_tcp_listen_data_ready;
1358                 set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
1359         } else {
1360                 dprintk("setting up TCP socket for reading\n");
1361                 sk->sk_state_change = svc_tcp_state_change;
1362                 sk->sk_data_ready = svc_tcp_data_ready;
1363                 sk->sk_write_space = svc_tcp_write_space;
1364 
1365                 svsk->sk_reclen = 0;
1366                 svsk->sk_tcplen = 0;
1367                 svsk->sk_datalen = 0;
1368                 memset(&svsk->sk_pages[0], 0, sizeof(svsk->sk_pages));
1369 
1370                 tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1371 
1372                 set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
1373                 if (sk->sk_state != TCP_ESTABLISHED)
1374                         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
1375         }
1376 }
1377 
1378 void svc_sock_update_bufs(struct svc_serv *serv)
1379 {
1380         /*
1381          * The number of server threads has changed. Update
1382          * rcvbuf and sndbuf accordingly on all sockets
1383          */
1384         struct svc_sock *svsk;
1385 
1386         spin_lock_bh(&serv->sv_lock);
1387         list_for_each_entry(svsk, &serv->sv_permsocks, sk_xprt.xpt_list)
1388                 set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
1389         spin_unlock_bh(&serv->sv_lock);
1390 }
1391 EXPORT_SYMBOL_GPL(svc_sock_update_bufs);
1392 
1393 /*
1394  * Initialize socket for RPC use and create svc_sock struct
1395  */
1396 static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
1397                                                 struct socket *sock,
1398                                                 int flags)
1399 {
1400         struct svc_sock *svsk;
1401         struct sock     *inet;
1402         int             pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
1403         int             err = 0;
1404 
1405         dprintk("svc: svc_setup_socket %p\n", sock);
1406         svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
1407         if (!svsk)
1408                 return ERR_PTR(-ENOMEM);
1409 
1410         inet = sock->sk;
1411 
1412         /* Register socket with portmapper */
1413         if (pmap_register)
1414                 err = svc_register(serv, sock_net(sock->sk), inet->sk_family,
1415                                      inet->sk_protocol,
1416                                      ntohs(inet_sk(inet)->inet_sport));
1417 
1418         if (err < 0) {
1419                 kfree(svsk);
1420                 return ERR_PTR(err);
1421         }
1422 
1423         inet->sk_user_data = svsk;
1424         svsk->sk_sock = sock;
1425         svsk->sk_sk = inet;
1426         svsk->sk_ostate = inet->sk_state_change;
1427         svsk->sk_odata = inet->sk_data_ready;
1428         svsk->sk_owspace = inet->sk_write_space;
1429 
1430         /* Initialize the socket */
1431         if (sock->type == SOCK_DGRAM)
1432                 svc_udp_init(svsk, serv);
1433         else {
1434                 /* initialise setting must have enough space to
1435                  * receive and respond to one request.
1436                  */
1437                 svc_sock_setbufsize(svsk->sk_sock, 4 * serv->sv_max_mesg,
1438                                         4 * serv->sv_max_mesg);
1439                 svc_tcp_init(svsk, serv);
1440         }
1441 
1442         dprintk("svc: svc_setup_socket created %p (inet %p)\n",
1443                                 svsk, svsk->sk_sk);
1444 
1445         return svsk;
1446 }
1447 
1448 bool svc_alien_sock(struct net *net, int fd)
1449 {
1450         int err;
1451         struct socket *sock = sockfd_lookup(fd, &err);
1452         bool ret = false;
1453 
1454         if (!sock)
1455                 goto out;
1456         if (sock_net(sock->sk) != net)
1457                 ret = true;
1458         sockfd_put(sock);
1459 out:
1460         return ret;
1461 }
1462 EXPORT_SYMBOL_GPL(svc_alien_sock);
1463 
1464 /**
1465  * svc_addsock - add a listener socket to an RPC service
1466  * @serv: pointer to RPC service to which to add a new listener
1467  * @fd: file descriptor of the new listener
1468  * @name_return: pointer to buffer to fill in with name of listener
1469  * @len: size of the buffer
1470  *
1471  * Fills in socket name and returns positive length of name if successful.
1472  * Name is terminated with '\n'.  On error, returns a negative errno
1473  * value.
1474  */
1475 int svc_addsock(struct svc_serv *serv, const int fd, char *name_return,
1476                 const size_t len)
1477 {
1478         int err = 0;
1479         struct socket *so = sockfd_lookup(fd, &err);
1480         struct svc_sock *svsk = NULL;
1481         struct sockaddr_storage addr;
1482         struct sockaddr *sin = (struct sockaddr *)&addr;
1483         int salen;
1484 
1485         if (!so)
1486                 return err;
1487         err = -EAFNOSUPPORT;
1488         if ((so->sk->sk_family != PF_INET) && (so->sk->sk_family != PF_INET6))
1489                 goto out;
1490         err =  -EPROTONOSUPPORT;
1491         if (so->sk->sk_protocol != IPPROTO_TCP &&
1492             so->sk->sk_protocol != IPPROTO_UDP)
1493                 goto out;
1494         err = -EISCONN;
1495         if (so->state > SS_UNCONNECTED)
1496                 goto out;
1497         err = -ENOENT;
1498         if (!try_module_get(THIS_MODULE))
1499                 goto out;
1500         svsk = svc_setup_socket(serv, so, SVC_SOCK_DEFAULTS);
1501         if (IS_ERR(svsk)) {
1502                 module_put(THIS_MODULE);
1503                 err = PTR_ERR(svsk);
1504                 goto out;
1505         }
1506         if (kernel_getsockname(svsk->sk_sock, sin, &salen) == 0)
1507                 svc_xprt_set_local(&svsk->sk_xprt, sin, salen);
1508         svc_add_new_perm_xprt(serv, &svsk->sk_xprt);
1509         return svc_one_sock_name(svsk, name_return, len);
1510 out:
1511         sockfd_put(so);
1512         return err;
1513 }
1514 EXPORT_SYMBOL_GPL(svc_addsock);
1515 
1516 /*
1517  * Create socket for RPC service.
1518  */
1519 static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
1520                                           int protocol,
1521                                           struct net *net,
1522                                           struct sockaddr *sin, int len,
1523                                           int flags)
1524 {
1525         struct svc_sock *svsk;
1526         struct socket   *sock;
1527         int             error;
1528         int             type;
1529         struct sockaddr_storage addr;
1530         struct sockaddr *newsin = (struct sockaddr *)&addr;
1531         int             newlen;
1532         int             family;
1533         int             val;
1534         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
1535 
1536         dprintk("svc: svc_create_socket(%s, %d, %s)\n",
1537                         serv->sv_program->pg_name, protocol,
1538                         __svc_print_addr(sin, buf, sizeof(buf)));
1539 
1540         if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
1541                 printk(KERN_WARNING "svc: only UDP and TCP "
1542                                 "sockets supported\n");
1543                 return ERR_PTR(-EINVAL);
1544         }
1545 
1546         type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
1547         switch (sin->sa_family) {
1548         case AF_INET6:
1549                 family = PF_INET6;
1550                 break;
1551         case AF_INET:
1552                 family = PF_INET;
1553                 break;
1554         default:
1555                 return ERR_PTR(-EINVAL);
1556         }
1557 
1558         error = __sock_create(net, family, type, protocol, &sock, 1);
1559         if (error < 0)
1560                 return ERR_PTR(error);
1561 
1562         svc_reclassify_socket(sock);
1563 
1564         /*
1565          * If this is an PF_INET6 listener, we want to avoid
1566          * getting requests from IPv4 remotes.  Those should
1567          * be shunted to a PF_INET listener via rpcbind.
1568          */
1569         val = 1;
1570         if (family == PF_INET6)
1571                 kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY,
1572                                         (char *)&val, sizeof(val));
1573 
1574         if (type == SOCK_STREAM)
1575                 sock->sk->sk_reuse = SK_CAN_REUSE; /* allow address reuse */
1576         error = kernel_bind(sock, sin, len);
1577         if (error < 0)
1578                 goto bummer;
1579 
1580         newlen = len;
1581         error = kernel_getsockname(sock, newsin, &newlen);
1582         if (error < 0)
1583                 goto bummer;
1584 
1585         if (protocol == IPPROTO_TCP) {
1586                 if ((error = kernel_listen(sock, 64)) < 0)
1587                         goto bummer;
1588         }
1589 
1590         svsk = svc_setup_socket(serv, sock, flags);
1591         if (IS_ERR(svsk)) {
1592                 error = PTR_ERR(svsk);
1593                 goto bummer;
1594         }
1595         svc_xprt_set_local(&svsk->sk_xprt, newsin, newlen);
1596         return (struct svc_xprt *)svsk;
1597 bummer:
1598         dprintk("svc: svc_create_socket error = %d\n", -error);
1599         sock_release(sock);
1600         return ERR_PTR(error);
1601 }
1602 
1603 /*
1604  * Detach the svc_sock from the socket so that no
1605  * more callbacks occur.
1606  */
1607 static void svc_sock_detach(struct svc_xprt *xprt)
1608 {
1609         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1610         struct sock *sk = svsk->sk_sk;
1611         wait_queue_head_t *wq;
1612 
1613         dprintk("svc: svc_sock_detach(%p)\n", svsk);
1614 
1615         /* put back the old socket callbacks */
1616         sk->sk_state_change = svsk->sk_ostate;
1617         sk->sk_data_ready = svsk->sk_odata;
1618         sk->sk_write_space = svsk->sk_owspace;
1619 
1620         wq = sk_sleep(sk);
1621         if (sunrpc_waitqueue_active(wq))
1622                 wake_up_interruptible(wq);
1623 }
1624 
1625 /*
1626  * Disconnect the socket, and reset the callbacks
1627  */
1628 static void svc_tcp_sock_detach(struct svc_xprt *xprt)
1629 {
1630         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1631 
1632         dprintk("svc: svc_tcp_sock_detach(%p)\n", svsk);
1633 
1634         svc_sock_detach(xprt);
1635 
1636         if (!test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
1637                 svc_tcp_clear_pages(svsk);
1638                 kernel_sock_shutdown(svsk->sk_sock, SHUT_RDWR);
1639         }
1640 }
1641 
1642 /*
1643  * Free the svc_sock's socket resources and the svc_sock itself.
1644  */
1645 static void svc_sock_free(struct svc_xprt *xprt)
1646 {
1647         struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
1648         dprintk("svc: svc_sock_free(%p)\n", svsk);
1649 
1650         if (svsk->sk_sock->file)
1651                 sockfd_put(svsk->sk_sock);
1652         else
1653                 sock_release(svsk->sk_sock);
1654         kfree(svsk);
1655 }
1656 
1657 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1658 /*
1659  * Create a back channel svc_xprt which shares the fore channel socket.
1660  */
1661 static struct svc_xprt *svc_bc_create_socket(struct svc_serv *serv,
1662                                              int protocol,
1663                                              struct net *net,
1664                                              struct sockaddr *sin, int len,
1665                                              int flags)
1666 {
1667         struct svc_sock *svsk;
1668         struct svc_xprt *xprt;
1669 
1670         if (protocol != IPPROTO_TCP) {
1671                 printk(KERN_WARNING "svc: only TCP sockets"
1672                         " supported on shared back channel\n");
1673                 return ERR_PTR(-EINVAL);
1674         }
1675 
1676         svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
1677         if (!svsk)
1678                 return ERR_PTR(-ENOMEM);
1679 
1680         xprt = &svsk->sk_xprt;
1681         svc_xprt_init(net, &svc_tcp_bc_class, xprt, serv);
1682 
1683         serv->sv_bc_xprt = xprt;
1684 
1685         return xprt;
1686 }
1687 
1688 /*
1689  * Free a back channel svc_sock.
1690  */
1691 static void svc_bc_sock_free(struct svc_xprt *xprt)
1692 {
1693         if (xprt)
1694                 kfree(container_of(xprt, struct svc_sock, sk_xprt));
1695 }
1696 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1697 

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