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27 * Mountain View, California 94043
29 * @(#)svc_udp.c 1.24 87/08/11 Copyr 1984 Sun Micro
30 * @(#)svc_udp.c 2.2 88/07/29 4.0 RPCSRC
31 * $FreeBSD: src/lib/libc/rpc/svc_udp.c,v 1.13 2000/01/27 23:06:41 jasone Exp $
32 * $DragonFly: src/lib/libc/rpc/svc_udp.c,v 1.5 2005/01/31 22:29:38 dillon Exp $
37 * Server side for UDP/IP based RPC. (Does some caching in the hopes of
38 * achieving execute-at-most-once semantics.)
40 * Copyright (C) 1984, Sun Microsystems, Inc.
43 #include "namespace.h"
49 #include <sys/socket.h>
51 #include "un-namespace.h"
53 #define rpc_buffer(xprt) ((xprt)->xp_p1)
54 #define MAX(a, b) ((a > b) ? a : b)
56 static bool_t svcudp_recv();
57 static bool_t svcudp_reply();
58 static enum xprt_stat svcudp_stat();
59 static bool_t svcudp_getargs();
60 static bool_t svcudp_freeargs();
61 static void svcudp_destroy();
62 static void cache_set (SVCXPRT *, u_long);
63 static int cache_get (SVCXPRT *, struct rpc_msg *, char **, u_long *);
65 static struct xp_ops svcudp_op = {
78 u_int su_iosz; /* byte size of send.recv buffer */
79 u_long su_xid; /* transaction id */
80 XDR su_xdrs; /* XDR handle */
81 char su_verfbody[MAX_AUTH_BYTES]; /* verifier body */
82 char * su_cache; /* cached data, NULL if no cache */
84 #define su_data(xprt) ((struct svcudp_data *)(xprt->xp_p2))
88 * xprt = svcudp_create(sock);
90 * If sock<0 then a socket is created, else sock is used.
91 * If the socket, sock is not bound to a port then svcudp_create
92 * binds it to an arbitrary port. In any (successful) case,
93 * xprt->xp_sock is the registered socket number and xprt->xp_port is the
94 * associated port number.
95 * Once *xprt is initialized, it is registered as a transporter;
96 * see (svc.h, xprt_register).
97 * The routines returns NULL if a problem occurred.
100 svcudp_bufcreate(sock, sendsz, recvsz)
102 u_int sendsz, recvsz;
104 bool_t madesock = FALSE;
106 struct svcudp_data *su;
107 struct sockaddr_in addr;
108 int len = sizeof(struct sockaddr_in);
110 if (sock == RPC_ANYSOCK) {
111 if ((sock = _socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
112 perror("svcudp_create: socket creation problem");
113 return ((SVCXPRT *)NULL);
117 memset((char *)&addr, 0, sizeof (addr));
118 addr.sin_len = sizeof(struct sockaddr_in);
119 addr.sin_family = AF_INET;
120 if (bindresvport(sock, &addr)) {
122 (void)_bind(sock, (struct sockaddr *)&addr, len);
124 if (_getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
125 perror("svcudp_create - cannot getsockname");
128 return ((SVCXPRT *)NULL);
130 xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
132 (void)fprintf(stderr, "svcudp_create: out of memory\n");
135 su = (struct svcudp_data *)mem_alloc(sizeof(*su));
137 (void)fprintf(stderr, "svcudp_create: out of memory\n");
140 su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
141 if ((rpc_buffer(xprt) = mem_alloc(su->su_iosz)) == NULL) {
142 (void)fprintf(stderr, "svcudp_create: out of memory\n");
146 &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
148 xprt->xp_p2 = (caddr_t)su;
149 xprt->xp_verf.oa_base = su->su_verfbody;
150 xprt->xp_ops = &svcudp_op;
151 xprt->xp_port = ntohs(addr.sin_port);
152 xprt->xp_sock = sock;
162 return(svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
165 static enum xprt_stat
174 svcudp_recv(xprt, msg)
178 struct svcudp_data *su = su_data(xprt);
179 XDR *xdrs = &(su->su_xdrs);
185 xprt->xp_addrlen = sizeof(struct sockaddr_in);
186 rlen = _recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
187 0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
188 if (rlen == -1 && errno == EINTR)
190 if (rlen == -1 || rlen < 4*sizeof(u_int32_t))
192 xdrs->x_op = XDR_DECODE;
194 if (! xdr_callmsg(xdrs, msg))
196 su->su_xid = msg->rm_xid;
197 if (su->su_cache != NULL) {
198 if (cache_get(xprt, msg, &reply, &replylen)) {
199 (void) _sendto(xprt->xp_sock, reply, (int) replylen, 0,
200 (struct sockaddr *) &xprt->xp_raddr, xprt->xp_addrlen);
208 svcudp_reply(xprt, msg)
212 struct svcudp_data *su = su_data(xprt);
213 XDR *xdrs = &(su->su_xdrs);
217 xdrs->x_op = XDR_ENCODE;
219 msg->rm_xid = su->su_xid;
220 if (xdr_replymsg(xdrs, msg)) {
221 slen = (int)XDR_GETPOS(xdrs);
222 if (_sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
223 (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
226 if (su->su_cache && slen >= 0) {
227 cache_set(xprt, (u_long) slen);
235 svcudp_getargs(xprt, xdr_args, args_ptr)
241 return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
245 svcudp_freeargs(xprt, xdr_args, args_ptr)
250 XDR *xdrs = &(su_data(xprt)->su_xdrs);
252 xdrs->x_op = XDR_FREE;
253 return ((*xdr_args)(xdrs, args_ptr));
260 struct svcudp_data *su = su_data(xprt);
262 xprt_unregister(xprt);
263 (void)_close(xprt->xp_sock);
264 XDR_DESTROY(&(su->su_xdrs));
265 mem_free(rpc_buffer(xprt), su->su_iosz);
266 mem_free((caddr_t)su, sizeof(struct svcudp_data));
267 mem_free((caddr_t)xprt, sizeof(SVCXPRT));
271 /***********this could be a separate file*********************/
274 * Fifo cache for udp server
275 * Copies pointers to reply buffers into fifo cache
276 * Buffers are sent again if retransmissions are detected.
279 #define SPARSENESS 4 /* 75% sparse */
281 #define CACHE_PERROR(msg) \
282 (void) fprintf(stderr,"%s\n", msg)
284 #define ALLOC(type, size) \
285 (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
287 #define BZERO(addr, type, size) \
288 memset((char *) addr, 0, sizeof(type) * (int) (size))
291 * An entry in the cache
293 typedef struct cache_node *cache_ptr;
296 * Index into cache is xid, proc, vers, prog and address
302 struct sockaddr_in cache_addr;
304 * The cached reply and length
307 u_long cache_replylen;
309 * Next node on the list, if there is a collision
311 cache_ptr cache_next;
320 u_long uc_size; /* size of cache */
321 cache_ptr *uc_entries; /* hash table of entries in cache */
322 cache_ptr *uc_fifo; /* fifo list of entries in cache */
323 u_long uc_nextvictim; /* points to next victim in fifo list */
324 u_long uc_prog; /* saved program number */
325 u_long uc_vers; /* saved version number */
326 u_long uc_proc; /* saved procedure number */
327 struct sockaddr_in uc_addr; /* saved caller's address */
332 * the hashing function
334 #define CACHE_LOC(transp, xid) \
335 (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
339 * Enable use of the cache.
340 * Note: there is no disable.
342 int svcudp_enablecache(transp, size)
346 struct svcudp_data *su = su_data(transp);
347 struct udp_cache *uc;
349 if (su->su_cache != NULL) {
350 CACHE_PERROR("enablecache: cache already enabled");
353 uc = ALLOC(struct udp_cache, 1);
355 CACHE_PERROR("enablecache: could not allocate cache");
359 uc->uc_nextvictim = 0;
360 uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
361 if (uc->uc_entries == NULL) {
362 CACHE_PERROR("enablecache: could not allocate cache data");
365 BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
366 uc->uc_fifo = ALLOC(cache_ptr, size);
367 if (uc->uc_fifo == NULL) {
368 CACHE_PERROR("enablecache: could not allocate cache fifo");
371 BZERO(uc->uc_fifo, cache_ptr, size);
372 su->su_cache = (char *) uc;
378 * Set an entry in the cache
381 cache_set(xprt, replylen)
387 struct svcudp_data *su = su_data(xprt);
388 struct udp_cache *uc = (struct udp_cache *) su->su_cache;
393 * Find space for the new entry, either by
394 * reusing an old entry, or by mallocing a new one
396 victim = uc->uc_fifo[uc->uc_nextvictim];
397 if (victim != NULL) {
398 loc = CACHE_LOC(xprt, victim->cache_xid);
399 for (vicp = &uc->uc_entries[loc];
400 *vicp != NULL && *vicp != victim;
401 vicp = &(*vicp)->cache_next)
404 CACHE_PERROR("cache_set: victim not found");
407 *vicp = victim->cache_next; /* remote from cache */
408 newbuf = victim->cache_reply;
410 victim = ALLOC(struct cache_node, 1);
411 if (victim == NULL) {
412 CACHE_PERROR("cache_set: victim alloc failed");
415 newbuf = mem_alloc(su->su_iosz);
416 if (newbuf == NULL) {
417 CACHE_PERROR("cache_set: could not allocate new rpc_buffer");
425 victim->cache_replylen = replylen;
426 victim->cache_reply = rpc_buffer(xprt);
427 rpc_buffer(xprt) = newbuf;
428 xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_ENCODE);
429 victim->cache_xid = su->su_xid;
430 victim->cache_proc = uc->uc_proc;
431 victim->cache_vers = uc->uc_vers;
432 victim->cache_prog = uc->uc_prog;
433 victim->cache_addr = uc->uc_addr;
434 loc = CACHE_LOC(xprt, victim->cache_xid);
435 victim->cache_next = uc->uc_entries[loc];
436 uc->uc_entries[loc] = victim;
437 uc->uc_fifo[uc->uc_nextvictim++] = victim;
438 uc->uc_nextvictim %= uc->uc_size;
442 * Try to get an entry from the cache
443 * return 1 if found, 0 if not found
446 cache_get(xprt, msg, replyp, replylenp)
454 struct svcudp_data *su = su_data(xprt);
455 struct udp_cache *uc = (struct udp_cache *) su->su_cache;
457 # define EQADDR(a1, a2) (memcmp(&a1, &a2, sizeof(a1)) == 0)
459 loc = CACHE_LOC(xprt, su->su_xid);
460 for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
461 if (ent->cache_xid == su->su_xid &&
462 ent->cache_proc == uc->uc_proc &&
463 ent->cache_vers == uc->uc_vers &&
464 ent->cache_prog == uc->uc_prog &&
465 EQADDR(ent->cache_addr, uc->uc_addr)) {
466 *replyp = ent->cache_reply;
467 *replylenp = ent->cache_replylen;
472 * Failed to find entry
473 * Remember a few things so we can do a set later
475 uc->uc_proc = msg->rm_call.cb_proc;
476 uc->uc_vers = msg->rm_call.cb_vers;
477 uc->uc_prog = msg->rm_call.cb_prog;
478 uc->uc_addr = xprt->xp_raddr;