xref: /illumos-gate/usr/src/ucblib/librpcsoc/svc_udp.c (revision 8c0b080c8ed055a259d8cd26b9f005211c6a9753)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 /*
41  * svc_udp.c,
42  * Server side for UDP/IP based RPC.  (Does some caching in the hopes of
43  * achieving execute-at-most-once semantics.)
44  */
45 
46 #include <rpc/rpc.h>
47 #include <rpc/clnt_soc.h>
48 #include <sys/socket.h>
49 #include <errno.h>
50 #include <syslog.h>
51 #include <malloc.h>
52 #include <stdio.h>
53 
54 
55 #define	rpc_buffer(xprt) ((xprt)->xp_p1)
56 
57 static struct xp_ops *svcudp_ops();
58 
59 extern int errno;
60 extern SVCXPRT *svc_xprt_alloc();
61 extern void svc_xprt_free();
62 extern int _socket(int, int, int);
63 extern int _bind(int, const struct sockaddr *, int);
64 extern int _getsockname(int, struct sockaddr *, int *);
65 extern int _listen(int, int);
66 extern int _accept(int, struct sockaddr *, int *);
67 extern int bindresvport(int, struct sockaddr_in *);
68 extern int _recvfrom(int, char *, int, int,
69 		struct sockaddr *, int *);
70 extern int _sendto(int, const char *, int, int,
71 		const struct sockaddr *, int);
72 
73 static int cache_get(SVCXPRT *, struct rpc_msg *,
74 		char **, uint_t *);
75 static void cache_set(SVCXPRT *, uint_t);
76 
77 /*
78  * kept in xprt->xp_p2
79  */
80 struct svcudp_data {
81 	u_int   su_iosz;		/* byte size of send.recv buffer */
82 	uint32_t su_xid;		/* transaction id */
83 	XDR	su_xdrs;		/* XDR handle */
84 	char	su_verfbody[MAX_AUTH_BYTES];	/* verifier body */
85 	char * 	su_cache;	/* cached data, NULL if no cache */
86 };
87 #define	su_data(xprt)	((struct svcudp_data *)(xprt->xp_p2))
88 
89 /*
90  * Usage:
91  *	xprt = svcudp_create(sock);
92  *
93  * If sock<0 then a socket is created, else sock is used.
94  * If the socket, sock is not bound to a port then svcudp_create
95  * binds it to an arbitrary port.  In any (successful) case,
96  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
97  * associated port number.
98  * Once *xprt is initialized, it is registered as a transporter;
99  * see (svc.h, xprt_register).
100  * The routines returns NULL if a problem occurred.
101  */
102 SVCXPRT *
svcudp_bufcreate(sock,sendsz,recvsz)103 svcudp_bufcreate(sock, sendsz, recvsz)
104 	register int sock;
105 	u_int sendsz, recvsz;
106 {
107 	bool_t madesock = FALSE;
108 	register SVCXPRT *xprt;
109 	register struct svcudp_data *su;
110 	struct sockaddr_in addr;
111 	int len = sizeof (struct sockaddr_in);
112 
113 	if (sock == RPC_ANYSOCK) {
114 		if ((sock = _socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
115 			(void) syslog(LOG_ERR, "svcudp_create: socket",
116 				" creation problem: %m");
117 			return ((SVCXPRT *)NULL);
118 		}
119 		madesock = TRUE;
120 	}
121 	memset((char *)&addr, 0, sizeof (addr));
122 	addr.sin_family = AF_INET;
123 	if (bindresvport(sock, &addr)) {
124 		addr.sin_port = 0;
125 		(void) _bind(sock, (struct sockaddr *)&addr, len);
126 	}
127 	if (_getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
128 		(void) syslog(LOG_ERR, "svcudp_create -",
129 			" cannot getsockname: %m");
130 		if (madesock)
131 			(void) close(sock);
132 		return ((SVCXPRT *)NULL);
133 	}
134 	xprt = svc_xprt_alloc();
135 	if (xprt == NULL) {
136 		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
137 		if (madesock)
138 			(void) close(sock);
139 		return ((SVCXPRT *)NULL);
140 	}
141 	su = (struct svcudp_data *)mem_alloc(sizeof (*su));
142 	if (su == NULL) {
143 		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
144 		svc_xprt_free(xprt);
145 		if (madesock)
146 			(void) close(sock);
147 		return ((SVCXPRT *)NULL);
148 	}
149 	su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
150 	if ((rpc_buffer(xprt) = (char *)mem_alloc(su->su_iosz)) == NULL) {
151 		(void) syslog(LOG_ERR, "svcudp_create: out of memory");
152 		mem_free((char *) su, sizeof (*su));
153 		svc_xprt_free(xprt);
154 		if (madesock)
155 			(void) close(sock);
156 		return ((SVCXPRT *)NULL);
157 	}
158 	xdrmem_create(
159 	    &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
160 	su->su_cache = NULL;
161 	xprt->xp_p2 = (caddr_t)su;
162 	xprt->xp_netid = NULL;
163 	xprt->xp_verf.oa_base = su->su_verfbody;
164 	xprt->xp_ops = svcudp_ops();
165 	xprt->xp_port = ntohs(addr.sin_port);
166 	xprt->xp_sock = sock;
167 	xprt->xp_rtaddr.buf = &xprt->xp_raddr[0];
168 	xprt_register(xprt);
169 	return (xprt);
170 }
171 
172 SVCXPRT *
svcudp_create(sock)173 svcudp_create(sock)
174 	int sock;
175 {
176 
177 	return (svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
178 }
179 
180 static enum xprt_stat
svcudp_stat(xprt)181 svcudp_stat(xprt)
182 	SVCXPRT *xprt;
183 {
184 
185 	return (XPRT_IDLE);
186 }
187 
188 static bool_t
svcudp_recv(xprt,msg)189 svcudp_recv(xprt, msg)
190 	register SVCXPRT *xprt;
191 	struct rpc_msg *msg;
192 {
193 	register struct svcudp_data *su = su_data(xprt);
194 	register XDR *xdrs = &(su->su_xdrs);
195 	register int rlen;
196 	char *reply;
197 	uint_t replylen;
198 
199 	again:
200 	xprt->xp_addrlen = sizeof (struct sockaddr_in);
201 	rlen = _recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
202 	    0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
203 	if (rlen == -1 && errno == EINTR)
204 		goto again;
205 	if (rlen < 4*sizeof (uint32_t))
206 		return (FALSE);
207 	xdrs->x_op = XDR_DECODE;
208 	XDR_SETPOS(xdrs, 0);
209 	if (! xdr_callmsg(xdrs, msg))
210 		return (FALSE);
211 	su->su_xid = msg->rm_xid;
212 	if (su->su_cache != NULL) {
213 		if (cache_get(xprt, msg, &reply, &replylen)) {
214 			(void) _sendto(xprt->xp_sock, reply, (int) replylen, 0,
215 				(struct sockaddr *) &xprt->xp_raddr,
216 				xprt->xp_addrlen);
217 			return (TRUE);
218 		}
219 	}
220 	return (TRUE);
221 }
222 
223 static bool_t
svcudp_reply(xprt,msg)224 svcudp_reply(xprt, msg)
225 	register SVCXPRT *xprt;
226 	struct rpc_msg *msg;
227 {
228 	register struct svcudp_data *su = su_data(xprt);
229 	register XDR *xdrs = &(su->su_xdrs);
230 	register int slen;
231 	register bool_t stat = FALSE;
232 
233 	xdrs->x_op = XDR_ENCODE;
234 	XDR_SETPOS(xdrs, 0);
235 	msg->rm_xid = su->su_xid;
236 	if (xdr_replymsg(xdrs, msg)) {
237 		slen = (int)XDR_GETPOS(xdrs);
238 		if (_sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
239 		    (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
240 		    == slen) {
241 			stat = TRUE;
242 			if (su->su_cache && slen >= 0) {
243 				(void) cache_set(xprt, (uint_t) slen);
244 			}
245 		}
246 	}
247 	return (stat);
248 }
249 
250 static bool_t
svcudp_getargs(xprt,xdr_args,args_ptr)251 svcudp_getargs(xprt, xdr_args, args_ptr)
252 	SVCXPRT *xprt;
253 	xdrproc_t xdr_args;
254 	caddr_t args_ptr;
255 {
256 
257 	return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
258 }
259 
260 static bool_t
svcudp_freeargs(xprt,xdr_args,args_ptr)261 svcudp_freeargs(xprt, xdr_args, args_ptr)
262 	SVCXPRT *xprt;
263 	xdrproc_t xdr_args;
264 	caddr_t args_ptr;
265 {
266 	register XDR *xdrs = &(su_data(xprt)->su_xdrs);
267 
268 	xdrs->x_op = XDR_FREE;
269 	return ((*xdr_args)(xdrs, args_ptr));
270 }
271 
272 static void
svcudp_destroy(xprt)273 svcudp_destroy(xprt)
274 	register SVCXPRT *xprt;
275 {
276 	register struct svcudp_data *su = su_data(xprt);
277 
278 	xprt_unregister(xprt);
279 	(void) close(xprt->xp_sock);
280 	XDR_DESTROY(&(su->su_xdrs));
281 	mem_free(rpc_buffer(xprt), su->su_iosz);
282 	mem_free((caddr_t)su, sizeof (struct svcudp_data));
283 	svc_xprt_free(xprt);
284 }
285 
286 
287 /* **********this could be a separate file********************* */
288 
289 /*
290  * Fifo cache for udp server
291  * Copies pointers to reply buffers into fifo cache
292  * Buffers are sent again if retransmissions are detected.
293  */
294 
295 #define	SPARSENESS 4	/* 75% sparse */
296 
297 #define	ALLOC(type, size)	\
298 	(type *) mem_alloc((unsigned) (sizeof (type) * (size)))
299 
300 #define	BZERO(addr, type, size)	 \
301 	memset((char *) (addr), 0, sizeof (type) * (int) (size))
302 
303 #define	FREE(addr, type, size)	\
304 	(void) mem_free((char *) (addr), (sizeof (type) * (size)))
305 
306 /*
307  * An entry in the cache
308  */
309 typedef struct cache_node *cache_ptr;
310 struct cache_node {
311 	/*
312 	 * Index into cache is xid, proc, vers, prog and address
313 	 */
314 	uint32_t cache_xid;
315 	uint32_t cache_proc;
316 	uint32_t cache_vers;
317 	uint32_t cache_prog;
318 	struct sockaddr_in cache_addr;
319 	/*
320 	 * The cached reply and length
321 	 */
322 	char * cache_reply;
323 	uint32_t cache_replylen;
324 	/*
325 	 * Next node on the list, if there is a collision
326 	 */
327 	cache_ptr cache_next;
328 };
329 
330 
331 
332 /*
333  * The entire cache
334  */
335 struct udp_cache {
336 	uint32_t uc_size;		/* size of cache */
337 	cache_ptr *uc_entries;	/* hash table of entries in cache */
338 	cache_ptr *uc_fifo;	/* fifo list of entries in cache */
339 	uint32_t uc_nextvictim;	/* points to next victim in fifo list */
340 	uint32_t uc_prog;		/* saved program number */
341 	uint32_t uc_vers;		/* saved version number */
342 	uint32_t uc_proc;		/* saved procedure number */
343 	struct sockaddr_in uc_addr; /* saved caller's address */
344 };
345 
346 
347 /*
348  * the hashing function
349  */
350 #define	CACHE_LOC(transp, xid)	\
351 	(xid % (SPARSENESS*((struct udp_cache *) \
352 	su_data(transp)->su_cache)->uc_size))
353 
354 
355 /*
356  * Enable use of the cache.
357  * Note: there is no disable.
358  */
359 int
svcudp_enablecache(transp,size)360 svcudp_enablecache(transp, size)
361 	SVCXPRT *transp;
362 	uint_t size;
363 {
364 	struct svcudp_data *su = su_data(transp);
365 	struct udp_cache *uc;
366 
367 	if (su->su_cache != NULL) {
368 		(void) syslog(LOG_ERR, "enablecache: cache already enabled");
369 		return (0);
370 	}
371 	uc = ALLOC(struct udp_cache, 1);
372 	if (uc == NULL) {
373 		(void) syslog(LOG_ERR, "enablecache: could not allocate cache");
374 		return (0);
375 	}
376 	uc->uc_size = size;
377 	uc->uc_nextvictim = 0;
378 	uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
379 	if (uc->uc_entries == NULL) {
380 		(void) syslog(LOG_ERR, "enablecache: could not",
381 			" allocate cache data");
382 		FREE(uc, struct udp_cache, 1);
383 		return (0);
384 	}
385 	BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
386 	uc->uc_fifo = ALLOC(cache_ptr, size);
387 	if (uc->uc_fifo == NULL) {
388 		(void) syslog(LOG_ERR, "enablecache: could not",
389 			" allocate cache fifo");
390 		FREE((char *)uc->uc_entries, cache_ptr, size * SPARSENESS);
391 		FREE((char *)uc, struct udp_cache, 1);
392 		return (0);
393 	}
394 	BZERO(uc->uc_fifo, cache_ptr, size);
395 	su->su_cache = (char *) uc;
396 	return (1);
397 }
398 
399 
400 /*
401  * Set an entry in the cache
402  */
403 static void
cache_set(xprt,replylen)404 cache_set(xprt, replylen)
405 	SVCXPRT *xprt;
406 	uint_t replylen;
407 {
408 	register cache_ptr victim;
409 	register cache_ptr *vicp;
410 	register struct svcudp_data *su = su_data(xprt);
411 	struct udp_cache *uc = (struct udp_cache *) su->su_cache;
412 	u_int loc;
413 	char *newbuf;
414 
415 	/*
416 	 * Find space for the new entry, either by
417 	 * reusing an old entry, or by mallocing a new one
418 	 */
419 	victim = uc->uc_fifo[uc->uc_nextvictim];
420 	if (victim != NULL) {
421 		loc = CACHE_LOC(xprt, victim->cache_xid);
422 		for (vicp = &uc->uc_entries[loc];
423 			*vicp != NULL && *vicp != victim;
424 			vicp = &(*vicp)->cache_next)
425 				;
426 		if (*vicp == NULL) {
427 			(void) syslog(LOG_ERR, "cache_set: victim not found");
428 			return;
429 		}
430 		*vicp = victim->cache_next;	/* remote from cache */
431 		newbuf = victim->cache_reply;
432 	} else {
433 		victim = ALLOC(struct cache_node, 1);
434 		if (victim == NULL) {
435 			(void) syslog(LOG_ERR, "cache_set: victim alloc",
436 				" failed");
437 			return;
438 		}
439 		newbuf = (char *)mem_alloc(su->su_iosz);
440 		if (newbuf == NULL) {
441 			(void) syslog(LOG_ERR, "cache_set: could not",
442 				" allocate new rpc_buffer");
443 			FREE(victim, struct cache_node, 1);
444 			return;
445 		}
446 	}
447 
448 	/*
449 	 * Store it away
450 	 */
451 	victim->cache_replylen = replylen;
452 	victim->cache_reply = rpc_buffer(xprt);
453 	rpc_buffer(xprt) = newbuf;
454 	xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt),
455 		su->su_iosz, XDR_ENCODE);
456 	victim->cache_xid = su->su_xid;
457 	victim->cache_proc = uc->uc_proc;
458 	victim->cache_vers = uc->uc_vers;
459 	victim->cache_prog = uc->uc_prog;
460 	victim->cache_addr = uc->uc_addr;
461 	loc = CACHE_LOC(xprt, victim->cache_xid);
462 	victim->cache_next = uc->uc_entries[loc];
463 	uc->uc_entries[loc] = victim;
464 	uc->uc_fifo[uc->uc_nextvictim++] = victim;
465 	uc->uc_nextvictim %= uc->uc_size;
466 }
467 
468 /*
469  * Try to get an entry from the cache
470  * return 1 if found, 0 if not found
471  */
472 static int
cache_get(xprt,msg,replyp,replylenp)473 cache_get(xprt, msg, replyp, replylenp)
474 	SVCXPRT *xprt;
475 	struct rpc_msg *msg;
476 	char **replyp;
477 	uint_t *replylenp;
478 {
479 	u_int loc;
480 	register cache_ptr ent;
481 	register struct svcudp_data *su = su_data(xprt);
482 	register struct udp_cache *uc = (struct udp_cache *) su->su_cache;
483 
484 #define	EQADDR(a1, a2) \
485 	(memcmp((char *)&a1, (char *)&a2, sizeof (a1)) == 0)
486 
487 	loc = CACHE_LOC(xprt, su->su_xid);
488 	for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
489 		if (ent->cache_xid == su->su_xid &&
490 			ent->cache_proc == uc->uc_proc &&
491 			ent->cache_vers == uc->uc_vers &&
492 			ent->cache_prog == uc->uc_prog &&
493 			EQADDR(ent->cache_addr, uc->uc_addr)) {
494 			*replyp = ent->cache_reply;
495 			*replylenp = ent->cache_replylen;
496 			return (1);
497 		}
498 	}
499 	/*
500 	 * Failed to find entry
501 	 * Remember a few things so we can do a set later
502 	 */
503 	uc->uc_proc = msg->rm_call.cb_proc;
504 	uc->uc_vers = msg->rm_call.cb_vers;
505 	uc->uc_prog = msg->rm_call.cb_prog;
506 	memcpy((char *)&uc->uc_addr, (char *)&xprt->xp_raddr,
507 		sizeof (struct sockaddr_in));
508 	return (0);
509 }
510 
511 static struct xp_ops *
svcudp_ops()512 svcudp_ops()
513 {
514 	static struct xp_ops ops;
515 
516 	if (ops.xp_recv == NULL) {
517 		ops.xp_recv = svcudp_recv;
518 		ops.xp_stat = svcudp_stat;
519 		ops.xp_getargs = svcudp_getargs;
520 		ops.xp_reply = svcudp_reply;
521 		ops.xp_freeargs = svcudp_freeargs;
522 		ops.xp_destroy = svcudp_destroy;
523 	}
524 	return (&ops);
525 }
526