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 #ifndef errno
  68 extern int errno;
  69 #endif
  70
  71 /*
  72  * kept in xprt->xp_p2
  73  */
  74 struct svcudp_data {
  75         u_int   su_iosz;        /* byte size of send.recv buffer */
  76         u_long  su_xid;         /* transaction id */
  77         XDR     su_xdrs;        /* XDR handle */
  78         char    su_verfbody[MAX_AUTH_BYTES];    /* verifier body */
  79         char *  su_cache;       /* cached data, NULL if no cache */
  80 };
  81 #define su_data(xprt)   ((struct svcudp_data *)(xprt->xp_p2))
  82
  83 /*
  84  * Usage:
  85  *      xprt = svcudp_create(sock);
  86  *
  87  * If sock<0 then a socket is created, else sock is used.
  88  * If the socket, sock is not bound to a port then svcudp_create
  89  * binds it to an arbitrary port.  In any (successful) case,
  90  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
  91  * associated port number.
  92  * Once *xprt is initialized, it is registered as a transporter;
  93  * see (svc.h, xprt_register).
  94  * The routines returns NULL if a problem occurred.
  95  */
  96 SVCXPRT *
  97 svcudp_bufcreate(sock, sendsz, recvsz)
  98         register int sock;
  99         u_int sendsz, recvsz;
 100 {
 101         bool_t madesock = FALSE;
 102         register SVCXPRT *xprt;
 103         register struct svcudp_data *su;
 104         struct sockaddr_in addr;
 105         int len = sizeof(struct sockaddr_in);
 106
 107         if (sock == RPC_ANYSOCK) {
 108                 if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 109                         perror(_("svcudp_create: socket creation problem"));
 110                         return ((SVCXPRT *)NULL);
 111                 }
 112                 madesock = TRUE;
 113         }
 114         bzero((char *)&addr, sizeof (addr));
 115         addr.sin_family = AF_INET;
 116         if (bindresvport(sock, &addr)) {
 117                 addr.sin_port = 0;
 118                 (void)bind(sock, (struct sockaddr *)&addr, len);
 119         }
 120         if (getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
 121                 perror(_("svcudp_create - cannot getsockname"));
 122                 if (madesock)
 123                         (void)close(sock);
 124                 return ((SVCXPRT *)NULL);
 125         }
 126         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 127         if (xprt == NULL) {
 128                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 129                 return (NULL);
 130         }
 131         su = (struct svcudp_data *)mem_alloc(sizeof(*su));
 132         if (su == NULL) {
 133                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 134                 return (NULL);
 135         }
 136         su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
 137         if ((rpc_buffer(xprt) = mem_alloc(su->su_iosz)) == NULL) {
 138                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 139                 return (NULL);
 140         }
 141         xdrmem_create(
 142             &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
 143         su->su_cache = NULL;
 144         xprt->xp_p2 = (caddr_t)su;
 145         xprt->xp_verf.oa_base = su->su_verfbody;
 146         xprt->xp_ops = &svcudp_op;
 147         xprt->xp_port = ntohs(addr.sin_port);
 148         xprt->xp_sock = sock;
 149         xprt_register(xprt);
 150         return (xprt);
 151 }
 152
 153 SVCXPRT *
 154 svcudp_create(sock)
 155         int sock;
 156 {
 157
 158         return(svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
 159 }
 160
 161 static enum xprt_stat
 162 svcudp_stat(xprt)
 163         SVCXPRT *xprt;
 164 {
 165
 166         return (XPRT_IDLE);
 167 }
 168
 169 static bool_t
 170 svcudp_recv(xprt, msg)
 171         register SVCXPRT *xprt;
 172         struct rpc_msg *msg;
 173 {
 174         register struct svcudp_data *su = su_data(xprt);
 175         register XDR *xdrs = &(su->su_xdrs);
 176         register int rlen;
 177         char *reply;
 178         u_long replylen;
 179
 180     again:
 181         xprt->xp_addrlen = sizeof(struct sockaddr_in);
 182         rlen = recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
 183             0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
 184         if (rlen == -1 && errno == EINTR)
 185                 goto again;
 186         if (rlen < 16)          /* < 4 32-bit ints? */
 187                 return (FALSE);
 188         xdrs->x_op = XDR_DECODE;
 189         XDR_SETPOS(xdrs, 0);
 190         if (! xdr_callmsg(xdrs, msg))
 191                 return (FALSE);
 192         su->su_xid = msg->rm_xid;
 193         if (su->su_cache != NULL) {
 194                 if (cache_get(xprt, msg, &reply, &replylen)) {
 195                         (void) sendto(xprt->xp_sock, reply, (int) replylen, 0,
 196                           (struct sockaddr *) &xprt->xp_raddr, xprt->xp_addrlen);
 197                         return (TRUE);
 198                 }
 199         }
 200         return (TRUE);
 201 }
 202
 203 static bool_t
 204 svcudp_reply(xprt, msg)
 205         register SVCXPRT *xprt;
 206         struct rpc_msg *msg;
 207 {
 208         register struct svcudp_data *su = su_data(xprt);
 209         register XDR *xdrs = &(su->su_xdrs);
 210         register int slen;
 211         register bool_t stat = FALSE;
 212
 213         xdrs->x_op = XDR_ENCODE;
 214         XDR_SETPOS(xdrs, 0);
 215         msg->rm_xid = su->su_xid;
 216         if (xdr_replymsg(xdrs, msg)) {
 217                 slen = (int)XDR_GETPOS(xdrs);
 218                 if (sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
 219                     (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
 220                     == slen) {
 221                         stat = TRUE;
 222                         if (su->su_cache && slen >= 0) {
 223                                 cache_set(xprt, (u_long) slen);
 224                         }
 225                 }
 226         }
 227         return (stat);
 228 }
 229
 230 static bool_t
 231 svcudp_getargs(xprt, xdr_args, args_ptr)
 232         SVCXPRT *xprt;
 233         xdrproc_t xdr_args;
 234         caddr_t args_ptr;
 235 {
 236
 237         return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
 238 }
 239
 240 static bool_t
 241 svcudp_freeargs(xprt, xdr_args, args_ptr)
 242         SVCXPRT *xprt;
 243         xdrproc_t xdr_args;
 244         caddr_t args_ptr;
 245 {
 246         register XDR *xdrs = &(su_data(xprt)->su_xdrs);
 247
 248         xdrs->x_op = XDR_FREE;
 249         return ((*xdr_args)(xdrs, args_ptr));
 250 }
 251
 252 static void
 253 svcudp_destroy(xprt)
 254         register SVCXPRT *xprt;
 255 {
 256         register struct svcudp_data *su = su_data(xprt);
 257
 258         xprt_unregister(xprt);
 259         (void)close(xprt->xp_sock);
 260         XDR_DESTROY(&(su->su_xdrs));
 261         mem_free(rpc_buffer(xprt), su->su_iosz);
 262         mem_free((caddr_t)su, sizeof(struct svcudp_data));
 263         mem_free((caddr_t)xprt, sizeof(SVCXPRT));
 264 }
 265
 266
 267 /***********this could be a separate file*********************/
 268
 269 /*
 270  * Fifo cache for udp server
 271  * Copies pointers to reply buffers into fifo cache
 272  * Buffers are sent again if retransmissions are detected.
 273  */
 274
 275 #define SPARSENESS 4    /* 75% sparse */
 276
 277 #define CACHE_PERROR(msg)       \
 278         (void) fprintf(stderr,"%s\n", msg)
 279
 280 #define ALLOC(type, size)       \
 281         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 282
 283 #define BZERO(addr, type, size)  \
 284         bzero((char *) addr, sizeof(type) * (int) (size))
 285
 286 /*
 287  * An entry in the cache
 288  */
 289 typedef struct cache_node *cache_ptr;
 290 struct cache_node {
 291         /*
 292          * Index into cache is xid, proc, vers, prog and address
 293          */
 294         u_long cache_xid;
 295         u_long cache_proc;
 296         u_long cache_vers;
 297         u_long cache_prog;
 298         struct sockaddr_in cache_addr;
 299         /*
 300          * The cached reply and length
 301          */
 302         char * cache_reply;
 303         u_long cache_replylen;
 304         /*
 305          * Next node on the list, if there is a collision
 306          */
 307         cache_ptr cache_next;
 308 };
 309
 310
 311
 312 /*
 313  * The entire cache
 314  */
 315 struct udp_cache {
 316         u_long uc_size;         /* size of cache */
 317         cache_ptr *uc_entries;  /* hash table of entries in cache */
 318         cache_ptr *uc_fifo;     /* fifo list of entries in cache */
 319         u_long uc_nextvictim;   /* points to next victim in fifo list */
 320         u_long uc_prog;         /* saved program number */
 321         u_long uc_vers;         /* saved version number */
 322         u_long uc_proc;         /* saved procedure number */
 323         struct sockaddr_in uc_addr; /* saved caller's address */
 324 };
 325
 326
 327 /*
 328  * the hashing function
 329  */
 330 #define CACHE_LOC(transp, xid)  \
 331  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 332
 333
 334 /*
 335  * Enable use of the cache.
 336  * Note: there is no disable.
 337  */
 338 svcudp_enablecache(transp, size)
 339         SVCXPRT *transp;
 340         u_long size;
 341 {
 342         struct svcudp_data *su = su_data(transp);
 343         struct udp_cache *uc;
 344
 345         if (su->su_cache != NULL) {
 346                 CACHE_PERROR(_("enablecache: cache already enabled"));
 347                 return(0);
 348         }
 349         uc = ALLOC(struct udp_cache, 1);
 350         if (uc == NULL) {
 351                 CACHE_PERROR(_("enablecache: could not allocate cache"));
 352                 return(0);
 353         }
 354         uc->uc_size = size;
 355         uc->uc_nextvictim = 0;
 356         uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
 357         if (uc->uc_entries == NULL) {
 358                 CACHE_PERROR(_("enablecache: could not allocate cache data"));
 359                 return(0);
 360         }
 361         BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
 362         uc->uc_fifo = ALLOC(cache_ptr, size);
 363         if (uc->uc_fifo == NULL) {
 364                 CACHE_PERROR(_("enablecache: could not allocate cache fifo"));
 365                 return(0);
 366         }
 367         BZERO(uc->uc_fifo, cache_ptr, size);
 368         su->su_cache = (char *) uc;
 369         return(1);
 370 }
 371
 372
 373 /*
 374  * Set an entry in the cache
 375  */
 376 static
 377 cache_set(xprt, replylen)
 378         SVCXPRT *xprt;
 379         u_long replylen;
 380 {
 381         register cache_ptr victim;
 382         register cache_ptr *vicp;
 383         register struct svcudp_data *su = su_data(xprt);
 384         struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 385         u_int loc;
 386         char *newbuf;
 387
 388         /*
 389          * Find space for the new entry, either by
 390          * reusing an old entry, or by mallocing a new one
 391          */
 392         victim = uc->uc_fifo[uc->uc_nextvictim];
 393         if (victim != NULL) {
 394                 loc = CACHE_LOC(xprt, victim->cache_xid);
 395                 for (vicp = &uc->uc_entries[loc];
 396                   *vicp != NULL && *vicp != victim;
 397                   vicp = &(*vicp)->cache_next)
 398                                 ;
 399                 if (*vicp == NULL) {
 400                         CACHE_PERROR(_("cache_set: victim not found"));
 401                         return;
 402                 }
 403                 *vicp = victim->cache_next;     /* remote from cache */
 404                 newbuf = victim->cache_reply;
 405         } else {
 406                 victim = ALLOC(struct cache_node, 1);
 407                 if (victim == NULL) {
 408                         CACHE_PERROR("cache_set: victim alloc failed");
 409                         return;
 410                 }
 411                 newbuf = mem_alloc(su->su_iosz);
 412                 if (newbuf == NULL) {
 413                         CACHE_PERROR("cache_set: could not allocate new rpc_buffer");
 414                         return;
 415                 }
 416         }
 417
 418         /*
 419          * Store it away
 420          */
 421         victim->cache_replylen = replylen;
 422         victim->cache_reply = rpc_buffer(xprt);
 423         rpc_buffer(xprt) = newbuf;
 424         xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_ENCODE);
 425         victim->cache_xid = su->su_xid;
 426         victim->cache_proc = uc->uc_proc;
 427         victim->cache_vers = uc->uc_vers;
 428         victim->cache_prog = uc->uc_prog;
 429         victim->cache_addr = uc->uc_addr;
 430         loc = CACHE_LOC(xprt, victim->cache_xid);
 431         victim->cache_next = uc->uc_entries[loc];
 432         uc->uc_entries[loc] = victim;
 433         uc->uc_fifo[uc->uc_nextvictim++] = victim;
 434         uc->uc_nextvictim %= uc->uc_size;
 435 }
 436
 437 /*
 438  * Try to get an entry from the cache
 439  * return 1 if found, 0 if not found
 440  */
 441 static
 442 cache_get(xprt, msg, replyp, replylenp)
 443         SVCXPRT *xprt;
 444         struct rpc_msg *msg;
 445         char **replyp;
 446         u_long *replylenp;
 447 {
 448         u_int loc;
 449         register cache_ptr ent;
 450         register struct svcudp_data *su = su_data(xprt);
 451         register struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 452
 453 #       define EQADDR(a1, a2)   (bcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
 454
 455         loc = CACHE_LOC(xprt, su->su_xid);
 456         for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
 457                 if (ent->cache_xid == su->su_xid &&
 458                   ent->cache_proc == uc->uc_proc &&
 459                   ent->cache_vers == uc->uc_vers &&
 460                   ent->cache_prog == uc->uc_prog &&
 461                   EQADDR(ent->cache_addr, uc->uc_addr)) {
 462                         *replyp = ent->cache_reply;
 463                         *replylenp = ent->cache_replylen;
 464                         return(1);
 465                 }
 466         }
 467         /*
 468          * Failed to find entry
 469          * Remember a few things so we can do a set later
 470          */
 471         uc->uc_proc = msg->rm_call.cb_proc;
 472         uc->uc_vers = msg->rm_call.cb_vers;
 473         uc->uc_prog = msg->rm_call.cb_prog;
 474         uc->uc_addr = xprt->xp_raddr;
 475         return(0);
 476 }