sunrpc/svc_udp.c

   1 /* @(#)svc_udp.c        2.2 88/07/29 4.0 RPCSRC */
   2 /*
   3  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   4  * unrestricted use provided that this legend is included on all tape
   5  * media and as a part of the software program in whole or part.  Users
   6  * may copy or modify Sun RPC without charge, but are not authorized
   7  * to license or distribute it to anyone else except as part of a product or
   8  * program developed by the user.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  */
  30 #if !defined(lint) && defined(SCCSIDS)
  31 static char sccsid[] = "@(#)svc_udp.c 1.24 87/08/11 Copyr 1984 Sun Micro";
  32 #endif
  33
  34 /*
  35  * svc_udp.c,
  36  * Server side for UDP/IP based RPC.  (Does some caching in the hopes of
  37  * achieving execute-at-most-once semantics.)
  38  *
  39  * Copyright (C) 1984, Sun Microsystems, Inc.
  40  */
  41
  42 #include <stdio.h>
  43 #include <rpc/rpc.h>
  44 #include <sys/socket.h>
  45 #include <errno.h>
  46
  47
  48 #define rpc_buffer(xprt) ((xprt)->xp_p1)
  49 #define MAX(a, b)     ((a > b) ? a : b)
  50
  51 static bool_t           svcudp_recv();
  52 static bool_t           svcudp_reply();
  53 static enum xprt_stat   svcudp_stat();
  54 static bool_t           svcudp_getargs();
  55 static bool_t           svcudp_freeargs();
  56 static void             svcudp_destroy();
  57
  58 static struct xp_ops svcudp_op = {
  59         svcudp_recv,
  60         svcudp_stat,
  61         svcudp_getargs,
  62         svcudp_reply,
  63         svcudp_freeargs,
  64         svcudp_destroy
  65 };
  66
  67 extern int errno;
  68
  69 /*
  70  * kept in xprt->xp_p2
  71  */
  72 struct svcudp_data {
  73         u_int   su_iosz;        /* byte size of send.recv buffer */
  74         u_long  su_xid;         /* transaction id */
  75         XDR     su_xdrs;        /* XDR handle */
  76         char    su_verfbody[MAX_AUTH_BYTES];    /* verifier body */
  77         char *  su_cache;       /* cached data, NULL if no cache */
  78 };
  79 #define su_data(xprt)   ((struct svcudp_data *)(xprt->xp_p2))
  80
  81 /*
  82  * Usage:
  83  *      xprt = svcudp_create(sock);
  84  *
  85  * If sock<0 then a socket is created, else sock is used.
  86  * If the socket, sock is not bound to a port then svcudp_create
  87  * binds it to an arbitrary port.  In any (successful) case,
  88  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
  89  * associated port number.
  90  * Once *xprt is initialized, it is registered as a transporter;
  91  * see (svc.h, xprt_register).
  92  * The routines returns NULL if a problem occurred.
  93  */
  94 SVCXPRT *
  95 svcudp_bufcreate(sock, sendsz, recvsz)
  96         register int sock;
  97         u_int sendsz, recvsz;
  98 {
  99         bool_t madesock = FALSE;
 100         register SVCXPRT *xprt;
 101         register struct svcudp_data *su;
 102         struct sockaddr_in addr;
 103         int len = sizeof(struct sockaddr_in);
 104
 105         if (sock == RPC_ANYSOCK) {
 106                 if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 107                         perror("svcudp_create: socket creation problem");
 108                         return ((SVCXPRT *)NULL);
 109                 }
 110                 madesock = TRUE;
 111         }
 112         bzero((char *)&addr, sizeof (addr));
 113         addr.sin_family = AF_INET;
 114         if (bindresvport(sock, &addr)) {
 115                 addr.sin_port = 0;
 116                 (void)bind(sock, (struct sockaddr *)&addr, len);
 117         }
 118         if (getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
 119                 perror("svcudp_create - cannot getsockname");
 120                 if (madesock)
 121                         (void)close(sock);
 122                 return ((SVCXPRT *)NULL);
 123         }
 124         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 125         if (xprt == NULL) {
 126                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 127                 return (NULL);
 128         }
 129         su = (struct svcudp_data *)mem_alloc(sizeof(*su));
 130         if (su == NULL) {
 131                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 132                 return (NULL);
 133         }
 134         su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
 135         if ((rpc_buffer(xprt) = mem_alloc(su->su_iosz)) == NULL) {
 136                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 137                 return (NULL);
 138         }
 139         xdrmem_create(
 140             &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
 141         su->su_cache = NULL;
 142         xprt->xp_p2 = (caddr_t)su;
 143         xprt->xp_verf.oa_base = su->su_verfbody;
 144         xprt->xp_ops = &svcudp_op;
 145         xprt->xp_port = ntohs(addr.sin_port);
 146         xprt->xp_sock = sock;
 147         xprt_register(xprt);
 148         return (xprt);
 149 }
 150
 151 SVCXPRT *
 152 svcudp_create(sock)
 153         int sock;
 154 {
 155
 156         return(svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
 157 }
 158
 159 static enum xprt_stat
 160 svcudp_stat(xprt)
 161         SVCXPRT *xprt;
 162 {
 163
 164         return (XPRT_IDLE);
 165 }
 166
 167 static bool_t
 168 svcudp_recv(xprt, msg)
 169         register SVCXPRT *xprt;
 170         struct rpc_msg *msg;
 171 {
 172         register struct svcudp_data *su = su_data(xprt);
 173         register XDR *xdrs = &(su->su_xdrs);
 174         register int rlen;
 175         char *reply;
 176         u_long replylen;
 177
 178     again:
 179         xprt->xp_addrlen = sizeof(struct sockaddr_in);
 180         rlen = recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
 181             0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
 182         if (rlen == -1 && errno == EINTR)
 183                 goto again;
 184         if (rlen < 4*sizeof(u_long))
 185                 return (FALSE);
 186         xdrs->x_op = XDR_DECODE;
 187         XDR_SETPOS(xdrs, 0);
 188         if (! xdr_callmsg(xdrs, msg))
 189                 return (FALSE);
 190         su->su_xid = msg->rm_xid;
 191         if (su->su_cache != NULL) {
 192                 if (cache_get(xprt, msg, &reply, &replylen)) {
 193                         (void) sendto(xprt->xp_sock, reply, (int) replylen, 0,
 194                           (struct sockaddr *) &xprt->xp_raddr, xprt->xp_addrlen);
 195                         return (TRUE);
 196                 }
 197         }
 198         return (TRUE);
 199 }
 200
 201 static bool_t
 202 svcudp_reply(xprt, msg)
 203         register SVCXPRT *xprt;
 204         struct rpc_msg *msg;
 205 {
 206         register struct svcudp_data *su = su_data(xprt);
 207         register XDR *xdrs = &(su->su_xdrs);
 208         register int slen;
 209         register bool_t stat = FALSE;
 210
 211         xdrs->x_op = XDR_ENCODE;
 212         XDR_SETPOS(xdrs, 0);
 213         msg->rm_xid = su->su_xid;
 214         if (xdr_replymsg(xdrs, msg)) {
 215                 slen = (int)XDR_GETPOS(xdrs);
 216                 if (sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
 217                     (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
 218                     == slen) {
 219                         stat = TRUE;
 220                         if (su->su_cache && slen >= 0) {
 221                                 cache_set(xprt, (u_long) slen);
 222                         }
 223                 }
 224         }
 225         return (stat);
 226 }
 227
 228 static bool_t
 229 svcudp_getargs(xprt, xdr_args, args_ptr)
 230         SVCXPRT *xprt;
 231         xdrproc_t xdr_args;
 232         caddr_t args_ptr;
 233 {
 234
 235         return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
 236 }
 237
 238 static bool_t
 239 svcudp_freeargs(xprt, xdr_args, args_ptr)
 240         SVCXPRT *xprt;
 241         xdrproc_t xdr_args;
 242         caddr_t args_ptr;
 243 {
 244         register XDR *xdrs = &(su_data(xprt)->su_xdrs);
 245
 246         xdrs->x_op = XDR_FREE;
 247         return ((*xdr_args)(xdrs, args_ptr));
 248 }
 249
 250 static void
 251 svcudp_destroy(xprt)
 252         register SVCXPRT *xprt;
 253 {
 254         register struct svcudp_data *su = su_data(xprt);
 255
 256         xprt_unregister(xprt);
 257         (void)close(xprt->xp_sock);
 258         XDR_DESTROY(&(su->su_xdrs));
 259         mem_free(rpc_buffer(xprt), su->su_iosz);
 260         mem_free((caddr_t)su, sizeof(struct svcudp_data));
 261         mem_free((caddr_t)xprt, sizeof(SVCXPRT));
 262 }
 263
 264
 265 /***********this could be a separate file*********************/
 266
 267 /*
 268  * Fifo cache for udp server
 269  * Copies pointers to reply buffers into fifo cache
 270  * Buffers are sent again if retransmissions are detected.
 271  */
 272
 273 #define SPARSENESS 4    /* 75% sparse */
 274
 275 #define CACHE_PERROR(msg)       \
 276         (void) fprintf(stderr,"%s\n", msg)
 277
 278 #define ALLOC(type, size)       \
 279         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 280
 281 #define BZERO(addr, type, size)  \
 282         bzero((char *) addr, sizeof(type) * (int) (size))
 283
 284 /*
 285  * An entry in the cache
 286  */
 287 typedef struct cache_node *cache_ptr;
 288 struct cache_node {
 289         /*
 290          * Index into cache is xid, proc, vers, prog and address
 291          */
 292         u_long cache_xid;
 293         u_long cache_proc;
 294         u_long cache_vers;
 295         u_long cache_prog;
 296         struct sockaddr_in cache_addr;
 297         /*
 298          * The cached reply and length
 299          */
 300         char * cache_reply;
 301         u_long cache_replylen;
 302         /*
 303          * Next node on the list, if there is a collision
 304          */
 305         cache_ptr cache_next;
 306 };
 307
 308
 309
 310 /*
 311  * The entire cache
 312  */
 313 struct udp_cache {
 314         u_long uc_size;         /* size of cache */
 315         cache_ptr *uc_entries;  /* hash table of entries in cache */
 316         cache_ptr *uc_fifo;     /* fifo list of entries in cache */
 317         u_long uc_nextvictim;   /* points to next victim in fifo list */
 318         u_long uc_prog;         /* saved program number */
 319         u_long uc_vers;         /* saved version number */
 320         u_long uc_proc;         /* saved procedure number */
 321         struct sockaddr_in uc_addr; /* saved caller's address */
 322 };
 323
 324
 325 /*
 326  * the hashing function
 327  */
 328 #define CACHE_LOC(transp, xid)  \
 329  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 330
 331
 332 /*
 333  * Enable use of the cache.
 334  * Note: there is no disable.
 335  */
 336 svcudp_enablecache(transp, size)
 337         SVCXPRT *transp;
 338         u_long size;
 339 {
 340         struct svcudp_data *su = su_data(transp);
 341         struct udp_cache *uc;
 342
 343         if (su->su_cache != NULL) {
 344                 CACHE_PERROR("enablecache: cache already enabled");
 345                 return(0);
 346         }
 347         uc = ALLOC(struct udp_cache, 1);
 348         if (uc == NULL) {
 349                 CACHE_PERROR("enablecache: could not allocate cache");
 350                 return(0);
 351         }
 352         uc->uc_size = size;
 353         uc->uc_nextvictim = 0;
 354         uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
 355         if (uc->uc_entries == NULL) {
 356                 CACHE_PERROR("enablecache: could not allocate cache data");
 357                 return(0);
 358         }
 359         BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
 360         uc->uc_fifo = ALLOC(cache_ptr, size);
 361         if (uc->uc_fifo == NULL) {
 362                 CACHE_PERROR("enablecache: could not allocate cache fifo");
 363                 return(0);
 364         }
 365         BZERO(uc->uc_fifo, cache_ptr, size);
 366         su->su_cache = (char *) uc;
 367         return(1);
 368 }
 369
 370
 371 /*
 372  * Set an entry in the cache
 373  */
 374 static
 375 cache_set(xprt, replylen)
 376         SVCXPRT *xprt;
 377         u_long replylen;
 378 {
 379         register cache_ptr victim;
 380         register cache_ptr *vicp;
 381         register struct svcudp_data *su = su_data(xprt);
 382         struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 383         u_int loc;
 384         char *newbuf;
 385
 386         /*
 387          * Find space for the new entry, either by
 388          * reusing an old entry, or by mallocing a new one
 389          */
 390         victim = uc->uc_fifo[uc->uc_nextvictim];
 391         if (victim != NULL) {
 392                 loc = CACHE_LOC(xprt, victim->cache_xid);
 393                 for (vicp = &uc->uc_entries[loc];
 394                   *vicp != NULL && *vicp != victim;
 395                   vicp = &(*vicp)->cache_next)
 396                                 ;
 397                 if (*vicp == NULL) {
 398                         CACHE_PERROR("cache_set: victim not found");
 399                         return;
 400                 }
 401                 *vicp = victim->cache_next;     /* remote from cache */
 402                 newbuf = victim->cache_reply;
 403         } else {
 404                 victim = ALLOC(struct cache_node, 1);
 405                 if (victim == NULL) {
 406                         CACHE_PERROR("cache_set: victim alloc failed");
 407                         return;
 408                 }
 409                 newbuf = mem_alloc(su->su_iosz);
 410                 if (newbuf == NULL) {
 411                         CACHE_PERROR("cache_set: could not allocate new rpc_buffer");
 412                         return;
 413                 }
 414         }
 415
 416         /*
 417          * Store it away
 418          */
 419         victim->cache_replylen = replylen;
 420         victim->cache_reply = rpc_buffer(xprt);
 421         rpc_buffer(xprt) = newbuf;
 422         xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_ENCODE);
 423         victim->cache_xid = su->su_xid;
 424         victim->cache_proc = uc->uc_proc;
 425         victim->cache_vers = uc->uc_vers;
 426         victim->cache_prog = uc->uc_prog;
 427         victim->cache_addr = uc->uc_addr;
 428         loc = CACHE_LOC(xprt, victim->cache_xid);
 429         victim->cache_next = uc->uc_entries[loc];
 430         uc->uc_entries[loc] = victim;
 431         uc->uc_fifo[uc->uc_nextvictim++] = victim;
 432         uc->uc_nextvictim %= uc->uc_size;
 433 }
 434
 435 /*
 436  * Try to get an entry from the cache
 437  * return 1 if found, 0 if not found
 438  */
 439 static
 440 cache_get(xprt, msg, replyp, replylenp)
 441         SVCXPRT *xprt;
 442         struct rpc_msg *msg;
 443         char **replyp;
 444         u_long *replylenp;
 445 {
 446         u_int loc;
 447         register cache_ptr ent;
 448         register struct svcudp_data *su = su_data(xprt);
 449         register struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 450
 451 #       define EQADDR(a1, a2)   (bcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
 452
 453         loc = CACHE_LOC(xprt, su->su_xid);
 454         for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
 455                 if (ent->cache_xid == su->su_xid &&
 456                   ent->cache_proc == uc->uc_proc &&
 457                   ent->cache_vers == uc->uc_vers &&
 458                   ent->cache_prog == uc->uc_prog &&
 459                   EQADDR(ent->cache_addr, uc->uc_addr)) {
 460                         *replyp = ent->cache_reply;
 461                         *replylenp = ent->cache_replylen;
 462                         return(1);
 463                 }
 464         }
 465         /*
 466          * Failed to find entry
 467          * Remember a few things so we can do a set later
 468          */
 469         uc->uc_proc = msg->rm_call.cb_proc;
 470         uc->uc_vers = msg->rm_call.cb_vers;
 471         uc->uc_prog = msg->rm_call.cb_prog;
 472         uc->uc_addr = xprt->xp_raddr;
 473         return(0);
 474 }
 475