1/*
2 * svc_udp.c,
3 * Server side for UDP/IP based RPC. (Does some caching in the hopes of
4 * achieving execute-at-most-once semantics.)
5 *
6 * Copyright (C) 2012-2021 Free Software Foundation, Inc.
7 * This file is part of the GNU C Library.
8 *
9 * The GNU C Library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * The GNU C Library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with the GNU C Library; if not, see
21 * <https://www.gnu.org/licenses/>.
22 *
23 * Copyright (c) 2010, Oracle America, Inc.
24 *
25 * Redistribution and use in source and binary forms, with or without
26 * modification, are permitted provided that the following conditions are
27 * met:
28 *
29 * * Redistributions of source code must retain the above copyright
30 * notice, this list of conditions and the following disclaimer.
31 * * Redistributions in binary form must reproduce the above
32 * copyright notice, this list of conditions and the following
33 * disclaimer in the documentation and/or other materials
34 * provided with the distribution.
35 * * Neither the name of the "Oracle America, Inc." nor the names of its
36 * contributors may be used to endorse or promote products derived
37 * from this software without specific prior written permission.
38 *
39 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
40 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
41 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
42 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
43 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
44 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
46 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
47 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
48 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
49 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
50 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
51 */
52
53#include <stdio.h>
54#include <unistd.h>
55#include <string.h>
56#include <rpc/rpc.h>
57#include <sys/socket.h>
58#include <errno.h>
59#include <libintl.h>
60
61#ifdef IP_PKTINFO
62#include <sys/uio.h>
63#endif
64
65#include <wchar.h>
66#include <libio/iolibio.h>
67#include <shlib-compat.h>
68
69#define rpc_buffer(xprt) ((xprt)->xp_p1)
70#ifndef MAX
71#define MAX(a, b) ((a > b) ? a : b)
72#endif
73
74static bool_t svcudp_recv (SVCXPRT *, struct rpc_msg *);
75static bool_t svcudp_reply (SVCXPRT *, struct rpc_msg *);
76static enum xprt_stat svcudp_stat (SVCXPRT *);
77static bool_t svcudp_getargs (SVCXPRT *, xdrproc_t, caddr_t);
78static bool_t svcudp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
79static void svcudp_destroy (SVCXPRT *);
80
81static const struct xp_ops svcudp_op =
82{
83 svcudp_recv,
84 svcudp_stat,
85 svcudp_getargs,
86 svcudp_reply,
87 svcudp_freeargs,
88 svcudp_destroy
89};
90
91static int cache_get (SVCXPRT *, struct rpc_msg *, char **replyp,
92 u_long *replylenp);
93static void cache_set (SVCXPRT *xprt, u_long replylen);
94
95/*
96 * kept in xprt->xp_p2
97 */
98struct svcudp_data
99 {
100 u_int su_iosz; /* byte size of send.recv buffer */
101 u_long su_xid; /* transaction id */
102 XDR su_xdrs; /* XDR handle */
103 char su_verfbody[MAX_AUTH_BYTES]; /* verifier body */
104 char *su_cache; /* cached data, NULL if no cache */
105 };
106#define su_data(xprt) ((struct svcudp_data *)(xprt->xp_p2))
107
108/*
109 * Usage:
110 * xprt = svcudp_create(sock);
111 *
112 * If sock<0 then a socket is created, else sock is used.
113 * If the socket, sock is not bound to a port then svcudp_create
114 * binds it to an arbitrary port. In any (successful) case,
115 * xprt->xp_sock is the registered socket number and xprt->xp_port is the
116 * associated port number.
117 * Once *xprt is initialized, it is registered as a transporter;
118 * see (svc.h, xprt_register).
119 * The routines returns NULL if a problem occurred.
120 */
121SVCXPRT *
122svcudp_bufcreate (int sock, u_int sendsz, u_int recvsz)
123{
124 bool_t madesock = FALSE;
125 SVCXPRT *xprt;
126 struct svcudp_data *su;
127 struct sockaddr_in addr;
128 socklen_t len = sizeof (struct sockaddr_in);
129 int pad;
130 void *buf;
131
132 if (sock == RPC_ANYSOCK)
133 {
134 if ((sock = __socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
135 {
136 perror (_("svcudp_create: socket creation problem"));
137 return (SVCXPRT *) NULL;
138 }
139 madesock = TRUE;
140 }
141 memset ((char *) &addr, 0, sizeof (addr));
142 addr.sin_family = AF_INET;
143 if (bindresvport (sock, &addr))
144 {
145 addr.sin_port = 0;
146 (void) __bind (sock, (struct sockaddr *) &addr, len);
147 }
148 if (__getsockname (sock, (struct sockaddr *) &addr, &len) != 0)
149 {
150 perror (_("svcudp_create - cannot getsockname"));
151 if (madesock)
152 (void) __close (sock);
153 return (SVCXPRT *) NULL;
154 }
155 xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
156 su = (struct svcudp_data *) mem_alloc (sizeof (*su));
157 buf = mem_alloc (((MAX (sendsz, recvsz) + 3) / 4) * 4);
158 if (xprt == NULL || su == NULL || buf == NULL)
159 {
160 (void) __fxprintf (NULL, "%s: %s",
161 "svcudp_create", _("out of memory\n"));
162 mem_free (xprt, sizeof (SVCXPRT));
163 mem_free (su, sizeof (*su));
164 mem_free (buf, ((MAX (sendsz, recvsz) + 3) / 4) * 4);
165 return NULL;
166 }
167 su->su_iosz = ((MAX (sendsz, recvsz) + 3) / 4) * 4;
168 rpc_buffer (xprt) = buf;
169 xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_DECODE);
170 su->su_cache = NULL;
171 xprt->xp_p2 = (caddr_t) su;
172 xprt->xp_verf.oa_base = su->su_verfbody;
173 xprt->xp_ops = &svcudp_op;
174 xprt->xp_port = ntohs (addr.sin_port);
175 xprt->xp_sock = sock;
176
177#ifdef IP_PKTINFO
178 if ((sizeof (struct iovec) + sizeof (struct msghdr)
179 + sizeof(struct cmsghdr) + sizeof (struct in_pktinfo))
180 > sizeof (xprt->xp_pad))
181 {
182 (void) __fxprintf (NULL,"%s", _("\
183svcudp_create: xp_pad is too small for IP_PKTINFO\n"));
184 return NULL;
185 }
186 pad = 1;
187 if (__setsockopt (sock, SOL_IP, IP_PKTINFO, (void *) &pad,
188 sizeof (pad)) == 0)
189 /* Set the padding to all 1s. */
190 pad = 0xff;
191 else
192#endif
193 /* Clear the padding. */
194 pad = 0;
195 memset (&xprt->xp_pad [0], pad, sizeof (xprt->xp_pad));
196
197 xprt_register (xprt);
198 return xprt;
199}
200#ifdef EXPORT_RPC_SYMBOLS
201libc_hidden_def (svcudp_bufcreate)
202#else
203libc_hidden_nolink_sunrpc (svcudp_bufcreate, GLIBC_2_0)
204#endif
205
206SVCXPRT *
207svcudp_create (int sock)
208{
209 return svcudp_bufcreate (sock, UDPMSGSIZE, UDPMSGSIZE);
210}
211#ifdef EXPORT_RPC_SYMBOLS
212libc_hidden_def (svcudp_create)
213#else
214libc_hidden_nolink_sunrpc (svcudp_create, GLIBC_2_0)
215#endif
216
217static enum xprt_stat
218svcudp_stat (SVCXPRT *xprt)
219{
220
221 return XPRT_IDLE;
222}
223
224static bool_t
225svcudp_recv (SVCXPRT *xprt, struct rpc_msg *msg)
226{
227 struct svcudp_data *su = su_data (xprt);
228 XDR *xdrs = &(su->su_xdrs);
229 int rlen;
230 char *reply;
231 u_long replylen;
232 socklen_t len;
233
234 /* It is very tricky when you have IP aliases. We want to make sure
235 that we are sending the packet from the IP address where the
236 incoming packet is addressed to. H.J. */
237#ifdef IP_PKTINFO
238 struct iovec *iovp;
239 struct msghdr *mesgp;
240#endif
241
242again:
243 /* FIXME -- should xp_addrlen be a size_t? */
244 len = (socklen_t) sizeof(struct sockaddr_in);
245#ifdef IP_PKTINFO
246 iovp = (struct iovec *) &xprt->xp_pad [0];
247 mesgp = (struct msghdr *) &xprt->xp_pad [sizeof (struct iovec)];
248 if (mesgp->msg_iovlen)
249 {
250 iovp->iov_base = rpc_buffer (xprt);
251 iovp->iov_len = su->su_iosz;
252 mesgp->msg_iov = iovp;
253 mesgp->msg_iovlen = 1;
254 mesgp->msg_name = &(xprt->xp_raddr);
255 mesgp->msg_namelen = len;
256 mesgp->msg_control = &xprt->xp_pad [sizeof (struct iovec)
257 + sizeof (struct msghdr)];
258 mesgp->msg_controllen = sizeof(xprt->xp_pad)
259 - sizeof (struct iovec) - sizeof (struct msghdr);
260 rlen = __recvmsg (xprt->xp_sock, mesgp, 0);
261 if (rlen >= 0)
262 {
263 struct cmsghdr *cmsg;
264 len = mesgp->msg_namelen;
265 cmsg = CMSG_FIRSTHDR (mesgp);
266 if (cmsg == NULL
267 || CMSG_NXTHDR (mesgp, cmsg) != NULL
268 || cmsg->cmsg_level != SOL_IP
269 || cmsg->cmsg_type != IP_PKTINFO
270 || cmsg->cmsg_len < (sizeof (struct cmsghdr)
271 + sizeof (struct in_pktinfo)))
272 {
273 /* Not a simple IP_PKTINFO, ignore it. */
274 mesgp->msg_control = NULL;
275 mesgp->msg_controllen = 0;
276 }
277 else
278 {
279 /* It was a simple IP_PKTIFO as we expected, discard the
280 interface field. */
281 struct in_pktinfo *pkti = (struct in_pktinfo *) CMSG_DATA (cmsg);
282 pkti->ipi_ifindex = 0;
283 }
284 }
285 }
286 else
287#endif
288 rlen = __recvfrom (xprt->xp_sock, rpc_buffer (xprt),
289 (int) su->su_iosz, 0,
290 (struct sockaddr *) &(xprt->xp_raddr), &len);
291 xprt->xp_addrlen = len;
292 if (rlen == -1)
293 {
294 if (errno == EINTR)
295 goto again;
296 __svc_accept_failed ();
297 }
298 if (rlen < 16) /* < 4 32-bit ints? */
299 return FALSE;
300 xdrs->x_op = XDR_DECODE;
301 XDR_SETPOS (xdrs, 0);
302 if (!xdr_callmsg (xdrs, msg))
303 return FALSE;
304 su->su_xid = msg->rm_xid;
305 if (su->su_cache != NULL)
306 {
307 if (cache_get (xprt, msg, &reply, &replylen))
308 {
309#ifdef IP_PKTINFO
310 if (mesgp->msg_iovlen)
311 {
312 iovp->iov_base = reply;
313 iovp->iov_len = replylen;
314 (void) __sendmsg (xprt->xp_sock, mesgp, 0);
315 }
316 else
317#endif
318 (void) __sendto (xprt->xp_sock, reply, (int) replylen, 0,
319 (struct sockaddr *) &xprt->xp_raddr, len);
320 return TRUE;
321 }
322 }
323 return TRUE;
324}
325
326static bool_t
327svcudp_reply (SVCXPRT *xprt, struct rpc_msg *msg)
328{
329 struct svcudp_data *su = su_data (xprt);
330 XDR *xdrs = &(su->su_xdrs);
331 int slen, sent;
332 bool_t stat = FALSE;
333#ifdef IP_PKTINFO
334 struct iovec *iovp;
335 struct msghdr *mesgp;
336#endif
337
338 xdrs->x_op = XDR_ENCODE;
339 XDR_SETPOS (xdrs, 0);
340 msg->rm_xid = su->su_xid;
341 if (xdr_replymsg (xdrs, msg))
342 {
343 slen = (int) XDR_GETPOS (xdrs);
344#ifdef IP_PKTINFO
345 mesgp = (struct msghdr *) &xprt->xp_pad [sizeof (struct iovec)];
346 if (mesgp->msg_iovlen)
347 {
348 iovp = (struct iovec *) &xprt->xp_pad [0];
349 iovp->iov_base = rpc_buffer (xprt);
350 iovp->iov_len = slen;
351 sent = __sendmsg (xprt->xp_sock, mesgp, 0);
352 }
353 else
354#endif
355 sent = __sendto (xprt->xp_sock, rpc_buffer (xprt), slen, 0,
356 (struct sockaddr *) &(xprt->xp_raddr),
357 xprt->xp_addrlen);
358 if (sent == slen)
359 {
360 stat = TRUE;
361 if (su->su_cache && slen >= 0)
362 {
363 cache_set (xprt, (u_long) slen);
364 }
365 }
366 }
367 return stat;
368}
369
370static bool_t
371svcudp_getargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
372{
373
374 return (*xdr_args) (&(su_data (xprt)->su_xdrs), args_ptr);
375}
376
377static bool_t
378svcudp_freeargs (SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
379{
380 XDR *xdrs = &(su_data (xprt)->su_xdrs);
381
382 xdrs->x_op = XDR_FREE;
383 return (*xdr_args) (xdrs, args_ptr);
384}
385
386static void
387svcudp_destroy (SVCXPRT *xprt)
388{
389 struct svcudp_data *su = su_data (xprt);
390
391 xprt_unregister (xprt);
392 (void) __close (xprt->xp_sock);
393 XDR_DESTROY (&(su->su_xdrs));
394 mem_free (rpc_buffer (xprt), su->su_iosz);
395 mem_free ((caddr_t) su, sizeof (struct svcudp_data));
396 mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
397}
398
399
400/***********this could be a separate file*********************/
401
402/*
403 * Fifo cache for udp server
404 * Copies pointers to reply buffers into fifo cache
405 * Buffers are sent again if retransmissions are detected.
406 */
407
408#define SPARSENESS 4 /* 75% sparse */
409
410#define CACHE_PERROR(msg) \
411 (void) __fxprintf(NULL, "%s\n", msg)
412
413#define ALLOC(type, size) \
414 (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
415
416#define CALLOC(type, size) \
417 (type *) calloc (sizeof (type), size)
418
419/*
420 * An entry in the cache
421 */
422typedef struct cache_node *cache_ptr;
423struct cache_node
424 {
425 /*
426 * Index into cache is xid, proc, vers, prog and address
427 */
428 u_long cache_xid;
429 u_long cache_proc;
430 u_long cache_vers;
431 u_long cache_prog;
432 struct sockaddr_in cache_addr;
433 /*
434 * The cached reply and length
435 */
436 char *cache_reply;
437 u_long cache_replylen;
438 /*
439 * Next node on the list, if there is a collision
440 */
441 cache_ptr cache_next;
442 };
443
444
445
446/*
447 * The entire cache
448 */
449struct udp_cache
450 {
451 u_long uc_size; /* size of cache */
452 cache_ptr *uc_entries; /* hash table of entries in cache */
453 cache_ptr *uc_fifo; /* fifo list of entries in cache */
454 u_long uc_nextvictim; /* points to next victim in fifo list */
455 u_long uc_prog; /* saved program number */
456 u_long uc_vers; /* saved version number */
457 u_long uc_proc; /* saved procedure number */
458 struct sockaddr_in uc_addr; /* saved caller's address */
459 };
460
461
462/*
463 * the hashing function
464 */
465#define CACHE_LOC(transp, xid) \
466 (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
467
468
469/*
470 * Enable use of the cache.
471 * Note: there is no disable.
472 */
473int
474svcudp_enablecache (SVCXPRT *transp, u_long size)
475{
476 struct svcudp_data *su = su_data (transp);
477 struct udp_cache *uc;
478
479 if (su->su_cache != NULL)
480 {
481 CACHE_PERROR (_("enablecache: cache already enabled"));
482 return 0;
483 }
484 uc = ALLOC (struct udp_cache, 1);
485 if (uc == NULL)
486 {
487 CACHE_PERROR (_("enablecache: could not allocate cache"));
488 return 0;
489 }
490 uc->uc_size = size;
491 uc->uc_nextvictim = 0;
492 uc->uc_entries = CALLOC (cache_ptr, size * SPARSENESS);
493 if (uc->uc_entries == NULL)
494 {
495 mem_free (uc, sizeof (struct udp_cache));
496 CACHE_PERROR (_("enablecache: could not allocate cache data"));
497 return 0;
498 }
499 uc->uc_fifo = CALLOC (cache_ptr, size);
500 if (uc->uc_fifo == NULL)
501 {
502 mem_free (uc->uc_entries, size * SPARSENESS);
503 mem_free (uc, sizeof (struct udp_cache));
504 CACHE_PERROR (_("enablecache: could not allocate cache fifo"));
505 return 0;
506 }
507 su->su_cache = (char *) uc;
508 return 1;
509}
510libc_hidden_nolink_sunrpc (svcudp_enablecache, GLIBC_2_0)
511
512
513/*
514 * Set an entry in the cache
515 */
516static void
517cache_set (SVCXPRT *xprt, u_long replylen)
518{
519 cache_ptr victim;
520 cache_ptr *vicp;
521 struct svcudp_data *su = su_data (xprt);
522 struct udp_cache *uc = (struct udp_cache *) su->su_cache;
523 u_int loc;
524 char *newbuf;
525
526 /*
527 * Find space for the new entry, either by
528 * reusing an old entry, or by mallocing a new one
529 */
530 victim = uc->uc_fifo[uc->uc_nextvictim];
531 if (victim != NULL)
532 {
533 loc = CACHE_LOC (xprt, victim->cache_xid);
534 for (vicp = &uc->uc_entries[loc];
535 *vicp != NULL && *vicp != victim;
536 vicp = &(*vicp)->cache_next)
537 ;
538 if (*vicp == NULL)
539 {
540 CACHE_PERROR (_("cache_set: victim not found"));
541 return;
542 }
543 *vicp = victim->cache_next; /* remote from cache */
544 newbuf = victim->cache_reply;
545 }
546 else
547 {
548 victim = ALLOC (struct cache_node, 1);
549 if (victim == NULL)
550 {
551 CACHE_PERROR (_("cache_set: victim alloc failed"));
552 return;
553 }
554 newbuf = mem_alloc (su->su_iosz);
555 if (newbuf == NULL)
556 {
557 mem_free (victim, sizeof (struct cache_node));
558 CACHE_PERROR (_("cache_set: could not allocate new rpc_buffer"));
559 return;
560 }
561 }
562
563 /*
564 * Store it away
565 */
566 victim->cache_replylen = replylen;
567 victim->cache_reply = rpc_buffer (xprt);
568 rpc_buffer (xprt) = newbuf;
569 xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_ENCODE);
570 victim->cache_xid = su->su_xid;
571 victim->cache_proc = uc->uc_proc;
572 victim->cache_vers = uc->uc_vers;
573 victim->cache_prog = uc->uc_prog;
574 victim->cache_addr = uc->uc_addr;
575 loc = CACHE_LOC (xprt, victim->cache_xid);
576 victim->cache_next = uc->uc_entries[loc];
577 uc->uc_entries[loc] = victim;
578 uc->uc_fifo[uc->uc_nextvictim++] = victim;
579 uc->uc_nextvictim %= uc->uc_size;
580}
581
582/*
583 * Try to get an entry from the cache
584 * return 1 if found, 0 if not found
585 */
586static int
587cache_get (SVCXPRT *xprt, struct rpc_msg *msg, char **replyp,
588 u_long *replylenp)
589{
590 u_int loc;
591 cache_ptr ent;
592 struct svcudp_data *su = su_data (xprt);
593 struct udp_cache *uc = (struct udp_cache *) su->su_cache;
594
595#define EQADDR(a1, a2) (memcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
596
597 loc = CACHE_LOC (xprt, su->su_xid);
598 for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next)
599 {
600 if (ent->cache_xid == su->su_xid &&
601 ent->cache_proc == uc->uc_proc &&
602 ent->cache_vers == uc->uc_vers &&
603 ent->cache_prog == uc->uc_prog &&
604 EQADDR (ent->cache_addr, uc->uc_addr))
605 {
606 *replyp = ent->cache_reply;
607 *replylenp = ent->cache_replylen;
608 return 1;
609 }
610 }
611 /*
612 * Failed to find entry
613 * Remember a few things so we can do a set later
614 */
615 uc->uc_proc = msg->rm_call.cb_proc;
616 uc->uc_vers = msg->rm_call.cb_vers;
617 uc->uc_prog = msg->rm_call.cb_prog;
618 memcpy (&uc->uc_addr, &xprt->xp_raddr, sizeof (uc->uc_addr));
619 return 0;
620}
621