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 #ifndef MAX
  50 # define MAX(a, b)     ((a > b) ? a : b)
  51 #endif
  52
  53 static bool_t           svcudp_recv();
  54 static bool_t           svcudp_reply();
  55 static enum xprt_stat   svcudp_stat();
  56 static bool_t           svcudp_getargs();
  57 static bool_t           svcudp_freeargs();
  58 static void             svcudp_destroy();
  59
  60 static struct xp_ops svcudp_op = {
  61         svcudp_recv,
  62         svcudp_stat,
  63         svcudp_getargs,
  64         svcudp_reply,
  65         svcudp_freeargs,
  66         svcudp_destroy
  67 };
  68
  69 #ifndef errno
  70 extern int errno;
  71 #endif
  72
  73 /*
  74  * kept in xprt->xp_p2
  75  */
  76 struct svcudp_data {
  77         u_int   su_iosz;        /* byte size of send.recv buffer */
  78         u_long  su_xid;         /* transaction id */
  79         XDR     su_xdrs;        /* XDR handle */
  80         char    su_verfbody[MAX_AUTH_BYTES];    /* verifier body */
  81         char *  su_cache;       /* cached data, NULL if no cache */
  82 };
  83 #define su_data(xprt)   ((struct svcudp_data *)(xprt->xp_p2))
  84
  85 /*
  86  * Usage:
  87  *      xprt = svcudp_create(sock);
  88  *
  89  * If sock<0 then a socket is created, else sock is used.
  90  * If the socket, sock is not bound to a port then svcudp_create
  91  * binds it to an arbitrary port.  In any (successful) case,
  92  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
  93  * associated port number.
  94  * Once *xprt is initialized, it is registered as a transporter;
  95  * see (svc.h, xprt_register).
  96  * The routines returns NULL if a problem occurred.
  97  */
  98 SVCXPRT *
  99 svcudp_bufcreate(sock, sendsz, recvsz)
 100         register int sock;
 101         u_int sendsz, recvsz;
 102 {
 103         bool_t madesock = FALSE;
 104         register SVCXPRT *xprt;
 105         register struct svcudp_data *su;
 106         struct sockaddr_in addr;
 107         int len = sizeof(struct sockaddr_in);
 108
 109         if (sock == RPC_ANYSOCK) {
 110                 if ((sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 111                         perror(_("svcudp_create: socket creation problem"));
 112                         return ((SVCXPRT *)NULL);
 113                 }
 114                 madesock = TRUE;
 115         }
 116         bzero((char *)&addr, sizeof (addr));
 117         addr.sin_family = AF_INET;
 118         if (bindresvport(sock, &addr)) {
 119                 addr.sin_port = 0;
 120                 (void)bind(sock, (struct sockaddr *)&addr, len);
 121         }
 122         if (getsockname(sock, (struct sockaddr *)&addr, &len) != 0) {
 123                 perror(_("svcudp_create - cannot getsockname"));
 124                 if (madesock)
 125                         (void)close(sock);
 126                 return ((SVCXPRT *)NULL);
 127         }
 128         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 129         if (xprt == NULL) {
 130                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 131                 return (NULL);
 132         }
 133         su = (struct svcudp_data *)mem_alloc(sizeof(*su));
 134         if (su == NULL) {
 135                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 136                 return (NULL);
 137         }
 138         su->su_iosz = ((MAX(sendsz, recvsz) + 3) / 4) * 4;
 139         if ((rpc_buffer(xprt) = mem_alloc(su->su_iosz)) == NULL) {
 140                 (void)fprintf(stderr, "svcudp_create: out of memory\n");
 141                 return (NULL);
 142         }
 143         xdrmem_create(
 144             &(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_DECODE);
 145         su->su_cache = NULL;
 146         xprt->xp_p2 = (caddr_t)su;
 147         xprt->xp_verf.oa_base = su->su_verfbody;
 148         xprt->xp_ops = &svcudp_op;
 149         xprt->xp_port = ntohs(addr.sin_port);
 150         xprt->xp_sock = sock;
 151         xprt_register(xprt);
 152         return (xprt);
 153 }
 154
 155 SVCXPRT *
 156 svcudp_create(sock)
 157         int sock;
 158 {
 159
 160         return(svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
 161 }
 162
 163 static enum xprt_stat
 164 svcudp_stat(xprt)
 165         SVCXPRT *xprt;
 166 {
 167
 168         return (XPRT_IDLE);
 169 }
 170
 171 static bool_t
 172 svcudp_recv(xprt, msg)
 173         register SVCXPRT *xprt;
 174         struct rpc_msg *msg;
 175 {
 176         register struct svcudp_data *su = su_data(xprt);
 177         register XDR *xdrs = &(su->su_xdrs);
 178         register int rlen;
 179         char *reply;
 180         u_long replylen;
 181
 182     again:
 183         xprt->xp_addrlen = sizeof(struct sockaddr_in);
 184         rlen = recvfrom(xprt->xp_sock, rpc_buffer(xprt), (int) su->su_iosz,
 185             0, (struct sockaddr *)&(xprt->xp_raddr), &(xprt->xp_addrlen));
 186         if (rlen == -1 && errno == EINTR)
 187                 goto again;
 188         if (rlen < 16)          /* < 4 32-bit ints? */
 189                 return (FALSE);
 190         xdrs->x_op = XDR_DECODE;
 191         XDR_SETPOS(xdrs, 0);
 192         if (! xdr_callmsg(xdrs, msg))
 193                 return (FALSE);
 194         su->su_xid = msg->rm_xid;
 195         if (su->su_cache != NULL) {
 196                 if (cache_get(xprt, msg, &reply, &replylen)) {
 197                         (void) sendto(xprt->xp_sock, reply, (int) replylen, 0,
 198                           (struct sockaddr *) &xprt->xp_raddr, xprt->xp_addrlen);
 199                         return (TRUE);
 200                 }
 201         }
 202         return (TRUE);
 203 }
 204
 205 static bool_t
 206 svcudp_reply(xprt, msg)
 207         register SVCXPRT *xprt;
 208         struct rpc_msg *msg;
 209 {
 210         register struct svcudp_data *su = su_data(xprt);
 211         register XDR *xdrs = &(su->su_xdrs);
 212         register int slen;
 213         register bool_t stat = FALSE;
 214
 215         xdrs->x_op = XDR_ENCODE;
 216         XDR_SETPOS(xdrs, 0);
 217         msg->rm_xid = su->su_xid;
 218         if (xdr_replymsg(xdrs, msg)) {
 219                 slen = (int)XDR_GETPOS(xdrs);
 220                 if (sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
 221                     (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
 222                     == slen) {
 223                         stat = TRUE;
 224                         if (su->su_cache && slen >= 0) {
 225                                 cache_set(xprt, (u_long) slen);
 226                         }
 227                 }
 228         }
 229         return (stat);
 230 }
 231
 232 static bool_t
 233 svcudp_getargs(xprt, xdr_args, args_ptr)
 234         SVCXPRT *xprt;
 235         xdrproc_t xdr_args;
 236         caddr_t args_ptr;
 237 {
 238
 239         return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
 240 }
 241
 242 static bool_t
 243 svcudp_freeargs(xprt, xdr_args, args_ptr)
 244         SVCXPRT *xprt;
 245         xdrproc_t xdr_args;
 246         caddr_t args_ptr;
 247 {
 248         register XDR *xdrs = &(su_data(xprt)->su_xdrs);
 249
 250         xdrs->x_op = XDR_FREE;
 251         return ((*xdr_args)(xdrs, args_ptr));
 252 }
 253
 254 static void
 255 svcudp_destroy(xprt)
 256         register SVCXPRT *xprt;
 257 {
 258         register struct svcudp_data *su = su_data(xprt);
 259
 260         xprt_unregister(xprt);
 261         (void)close(xprt->xp_sock);
 262         XDR_DESTROY(&(su->su_xdrs));
 263         mem_free(rpc_buffer(xprt), su->su_iosz);
 264         mem_free((caddr_t)su, sizeof(struct svcudp_data));
 265         mem_free((caddr_t)xprt, sizeof(SVCXPRT));
 266 }
 267
 268
 269 /***********this could be a separate file*********************/
 270
 271 /*
 272  * Fifo cache for udp server
 273  * Copies pointers to reply buffers into fifo cache
 274  * Buffers are sent again if retransmissions are detected.
 275  */
 276
 277 #define SPARSENESS 4    /* 75% sparse */
 278
 279 #define CACHE_PERROR(msg)       \
 280         (void) fprintf(stderr,"%s\n", msg)
 281
 282 #define ALLOC(type, size)       \
 283         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 284
 285 #define BZERO(addr, type, size)  \
 286         bzero((char *) addr, sizeof(type) * (int) (size))
 287
 288 /*
 289  * An entry in the cache
 290  */
 291 typedef struct cache_node *cache_ptr;
 292 struct cache_node {
 293         /*
 294          * Index into cache is xid, proc, vers, prog and address
 295          */
 296         u_long cache_xid;
 297         u_long cache_proc;
 298         u_long cache_vers;
 299         u_long cache_prog;
 300         struct sockaddr_in cache_addr;
 301         /*
 302          * The cached reply and length
 303          */
 304         char * cache_reply;
 305         u_long cache_replylen;
 306         /*
 307          * Next node on the list, if there is a collision
 308          */
 309         cache_ptr cache_next;
 310 };
 311
 312
 313
 314 /*
 315  * The entire cache
 316  */
 317 struct udp_cache {
 318         u_long uc_size;         /* size of cache */
 319         cache_ptr *uc_entries;  /* hash table of entries in cache */
 320         cache_ptr *uc_fifo;     /* fifo list of entries in cache */
 321         u_long uc_nextvictim;   /* points to next victim in fifo list */
 322         u_long uc_prog;         /* saved program number */
 323         u_long uc_vers;         /* saved version number */
 324         u_long uc_proc;         /* saved procedure number */
 325         struct sockaddr_in uc_addr; /* saved caller's address */
 326 };
 327
 328
 329 /*
 330  * the hashing function
 331  */
 332 #define CACHE_LOC(transp, xid)  \
 333  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 334
 335
 336 /*
 337  * Enable use of the cache.
 338  * Note: there is no disable.
 339  */
 340 svcudp_enablecache(transp, size)
 341         SVCXPRT *transp;
 342         u_long size;
 343 {
 344         struct svcudp_data *su = su_data(transp);
 345         struct udp_cache *uc;
 346
 347         if (su->su_cache != NULL) {
 348                 CACHE_PERROR(_("enablecache: cache already enabled"));
 349                 return(0);
 350         }
 351         uc = ALLOC(struct udp_cache, 1);
 352         if (uc == NULL) {
 353                 CACHE_PERROR(_("enablecache: could not allocate cache"));
 354                 return(0);
 355         }
 356         uc->uc_size = size;
 357         uc->uc_nextvictim = 0;
 358         uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
 359         if (uc->uc_entries == NULL) {
 360                 CACHE_PERROR(_("enablecache: could not allocate cache data"));
 361                 return(0);
 362         }
 363         BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
 364         uc->uc_fifo = ALLOC(cache_ptr, size);
 365         if (uc->uc_fifo == NULL) {
 366                 CACHE_PERROR(_("enablecache: could not allocate cache fifo"));
 367                 return(0);
 368         }
 369         BZERO(uc->uc_fifo, cache_ptr, size);
 370         su->su_cache = (char *) uc;
 371         return(1);
 372 }
 373
 374
 375 /*
 376  * Set an entry in the cache
 377  */
 378 static
 379 cache_set(xprt, replylen)
 380         SVCXPRT *xprt;
 381         u_long replylen;
 382 {
 383         register cache_ptr victim;
 384         register cache_ptr *vicp;
 385         register struct svcudp_data *su = su_data(xprt);
 386         struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 387         u_int loc;
 388         char *newbuf;
 389
 390         /*
 391          * Find space for the new entry, either by
 392          * reusing an old entry, or by mallocing a new one
 393          */
 394         victim = uc->uc_fifo[uc->uc_nextvictim];
 395         if (victim != NULL) {
 396                 loc = CACHE_LOC(xprt, victim->cache_xid);
 397                 for (vicp = &uc->uc_entries[loc];
 398                   *vicp != NULL && *vicp != victim;
 399                   vicp = &(*vicp)->cache_next)
 400                                 ;
 401                 if (*vicp == NULL) {
 402                         CACHE_PERROR(_("cache_set: victim not found"));
 403                         return;
 404                 }
 405                 *vicp = victim->cache_next;     /* remote from cache */
 406                 newbuf = victim->cache_reply;
 407         } else {
 408                 victim = ALLOC(struct cache_node, 1);
 409                 if (victim == NULL) {
 410                         CACHE_PERROR("cache_set: victim alloc failed");
 411                         return;
 412                 }
 413                 newbuf = mem_alloc(su->su_iosz);
 414                 if (newbuf == NULL) {
 415                         CACHE_PERROR("cache_set: could not allocate new rpc_buffer");
 416                         return;
 417                 }
 418         }
 419
 420         /*
 421          * Store it away
 422          */
 423         victim->cache_replylen = replylen;
 424         victim->cache_reply = rpc_buffer(xprt);
 425         rpc_buffer(xprt) = newbuf;
 426         xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_ENCODE);
 427         victim->cache_xid = su->su_xid;
 428         victim->cache_proc = uc->uc_proc;
 429         victim->cache_vers = uc->uc_vers;
 430         victim->cache_prog = uc->uc_prog;
 431         victim->cache_addr = uc->uc_addr;
 432         loc = CACHE_LOC(xprt, victim->cache_xid);
 433         victim->cache_next = uc->uc_entries[loc];
 434         uc->uc_entries[loc] = victim;
 435         uc->uc_fifo[uc->uc_nextvictim++] = victim;
 436         uc->uc_nextvictim %= uc->uc_size;
 437 }
 438
 439 /*
 440  * Try to get an entry from the cache
 441  * return 1 if found, 0 if not found
 442  */
 443 static
 444 cache_get(xprt, msg, replyp, replylenp)
 445         SVCXPRT *xprt;
 446         struct rpc_msg *msg;
 447         char **replyp;
 448         u_long *replylenp;
 449 {
 450         u_int loc;
 451         register cache_ptr ent;
 452         register struct svcudp_data *su = su_data(xprt);
 453         register struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 454
 455 #       define EQADDR(a1, a2)   (bcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
 456
 457         loc = CACHE_LOC(xprt, su->su_xid);
 458         for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
 459                 if (ent->cache_xid == su->su_xid &&
 460                   ent->cache_proc == uc->uc_proc &&
 461                   ent->cache_vers == uc->uc_vers &&
 462                   ent->cache_prog == uc->uc_prog &&
 463                   EQADDR(ent->cache_addr, uc->uc_addr)) {
 464                         *replyp = ent->cache_reply;
 465                         *replylenp = ent->cache_replylen;
 466                         return(1);
 467                 }
 468         }
 469         /*
 470          * Failed to find entry
 471          * Remember a few things so we can do a set later
 472          */
 473         uc->uc_proc = msg->rm_call.cb_proc;
 474         uc->uc_vers = msg->rm_call.cb_vers;
 475         uc->uc_prog = msg->rm_call.cb_prog;
 476         uc->uc_addr = xprt->xp_raddr;
 477         return(0);
 478 }