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 <unistd.h>
  44 #include <string.h>
  45 #include <rpc/rpc.h>
  46 #include <sys/socket.h>
  47 #include <errno.h>
  48
  49
  50 #define rpc_buffer(xprt) ((xprt)->xp_p1)
  51 #ifndef MAX
  52 #define MAX(a, b)     ((a > b) ? a : b)
  53 #endif
  54
  55 static bool_t svcudp_recv (SVCXPRT *, struct rpc_msg *);
  56 static bool_t svcudp_reply (SVCXPRT *, struct rpc_msg *);
  57 static enum xprt_stat svcudp_stat (SVCXPRT *);
  58 static bool_t svcudp_getargs (SVCXPRT *, xdrproc_t, caddr_t);
  59 static bool_t svcudp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
  60 static void svcudp_destroy (SVCXPRT *);
  61
  62 static const struct xp_ops svcudp_op =
  63 {
  64   svcudp_recv,
  65   svcudp_stat,
  66   svcudp_getargs,
  67   svcudp_reply,
  68   svcudp_freeargs,
  69   svcudp_destroy
  70 };
  71
  72 static int cache_get (SVCXPRT *, struct rpc_msg *, char **replyp,
  73                       u_long *replylenp);
  74 static void cache_set (SVCXPRT *xprt, u_long replylen);
  75
  76 /*
  77  * kept in xprt->xp_p2
  78  */
  79 struct svcudp_data
  80   {
  81     u_int su_iosz;              /* byte size of send.recv buffer */
  82     u_long 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 *
 103 svcudp_bufcreate (sock, sendsz, recvsz)
 104      int sock;
 105      u_int sendsz, recvsz;
 106 {
 107   bool_t madesock = FALSE;
 108   SVCXPRT *xprt;
 109   struct svcudp_data *su;
 110   struct sockaddr_in addr;
 111   size_t len = sizeof (struct sockaddr_in);
 112
 113   if (sock == RPC_ANYSOCK)
 114     {
 115       if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
 116         {
 117           perror (_("svcudp_create: socket creation problem"));
 118           return (SVCXPRT *) NULL;
 119         }
 120       madesock = TRUE;
 121     }
 122   bzero ((char *) &addr, sizeof (addr));
 123   addr.sin_family = AF_INET;
 124   if (bindresvport (sock, &addr))
 125     {
 126       addr.sin_port = 0;
 127       (void) bind (sock, (struct sockaddr *) &addr, len);
 128     }
 129   if (getsockname (sock, (struct sockaddr *) &addr, &len) != 0)
 130     {
 131       perror (_("svcudp_create - cannot getsockname"));
 132       if (madesock)
 133         (void) close (sock);
 134       return (SVCXPRT *) NULL;
 135     }
 136   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 137   if (xprt == NULL)
 138     {
 139       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 140       return NULL;
 141     }
 142   su = (struct svcudp_data *) mem_alloc (sizeof (*su));
 143   if (su == NULL)
 144     {
 145       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 146       return NULL;
 147     }
 148   su->su_iosz = ((MAX (sendsz, recvsz) + 3) / 4) * 4;
 149   if ((rpc_buffer (xprt) = mem_alloc (su->su_iosz)) == NULL)
 150     {
 151       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 152       return NULL;
 153     }
 154   xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_DECODE);
 155   su->su_cache = NULL;
 156   xprt->xp_p2 = (caddr_t) su;
 157   xprt->xp_verf.oa_base = su->su_verfbody;
 158   xprt->xp_ops = &svcudp_op;
 159   xprt->xp_port = ntohs (addr.sin_port);
 160   xprt->xp_sock = sock;
 161   xprt_register (xprt);
 162   return xprt;
 163 }
 164
 165 SVCXPRT *
 166 svcudp_create (sock)
 167      int sock;
 168 {
 169
 170   return svcudp_bufcreate (sock, UDPMSGSIZE, UDPMSGSIZE);
 171 }
 172
 173 static enum xprt_stat
 174 svcudp_stat (xprt)
 175      SVCXPRT *xprt;
 176 {
 177
 178   return XPRT_IDLE;
 179 }
 180
 181 static bool_t
 182 svcudp_recv (xprt, msg)
 183      SVCXPRT *xprt;
 184      struct rpc_msg *msg;
 185 {
 186   struct svcudp_data *su = su_data (xprt);
 187   XDR *xdrs = &(su->su_xdrs);
 188   int rlen;
 189   char *reply;
 190   u_long replylen;
 191   size_t len;
 192
 193 again:
 194   /* FIXME -- should xp_addrlen be a size_t?  */
 195   len = sizeof(struct sockaddr_in);
 196   rlen = recvfrom (xprt->xp_sock, rpc_buffer (xprt), (int) su->su_iosz, 0,
 197                    (struct sockaddr *) &(xprt->xp_raddr), &len);
 198   xprt->xp_addrlen = len;
 199   if (rlen == -1 && errno == EINTR)
 200     goto again;
 201   if (rlen < 16)                /* < 4 32-bit ints? */
 202     return FALSE;
 203   xdrs->x_op = XDR_DECODE;
 204   XDR_SETPOS (xdrs, 0);
 205   if (!xdr_callmsg (xdrs, msg))
 206     return FALSE;
 207   su->su_xid = msg->rm_xid;
 208   if (su->su_cache != NULL)
 209     {
 210       if (cache_get (xprt, msg, &reply, &replylen))
 211         {
 212           (void) sendto (xprt->xp_sock, reply, (int) replylen, 0,
 213                          (struct sockaddr *) &xprt->xp_raddr, len);
 214           return TRUE;
 215         }
 216     }
 217   return TRUE;
 218 }
 219
 220 static bool_t
 221 svcudp_reply (xprt, msg)
 222      SVCXPRT *xprt;
 223      struct rpc_msg *msg;
 224 {
 225   struct svcudp_data *su = su_data (xprt);
 226   XDR *xdrs = &(su->su_xdrs);
 227   int slen;
 228   bool_t stat = FALSE;
 229
 230   xdrs->x_op = XDR_ENCODE;
 231   XDR_SETPOS (xdrs, 0);
 232   msg->rm_xid = su->su_xid;
 233   if (xdr_replymsg (xdrs, msg))
 234     {
 235       slen = (int) XDR_GETPOS (xdrs);
 236       if (sendto (xprt->xp_sock, rpc_buffer (xprt), slen, 0,
 237                   (struct sockaddr *) &(xprt->xp_raddr), xprt->xp_addrlen)
 238           == slen)
 239         {
 240           stat = TRUE;
 241           if (su->su_cache && slen >= 0)
 242             {
 243               cache_set (xprt, (u_long) slen);
 244             }
 245         }
 246     }
 247   return stat;
 248 }
 249
 250 static bool_t
 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
 261 svcudp_freeargs (xprt, xdr_args, args_ptr)
 262      SVCXPRT *xprt;
 263      xdrproc_t xdr_args;
 264      caddr_t args_ptr;
 265 {
 266   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
 273 svcudp_destroy (xprt)
 274      SVCXPRT *xprt;
 275 {
 276   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   mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
 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 CACHE_PERROR(msg)       \
 298         (void) fprintf(stderr,"%s\n", msg)
 299
 300 #define ALLOC(type, size)       \
 301         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 302
 303 #define BZERO(addr, type, size)  \
 304         bzero((char *) addr, sizeof(type) * (int) (size))
 305
 306 /*
 307  * An entry in the cache
 308  */
 309 typedef struct cache_node *cache_ptr;
 310 struct cache_node
 311   {
 312     /*
 313      * Index into cache is xid, proc, vers, prog and address
 314      */
 315     u_long cache_xid;
 316     u_long cache_proc;
 317     u_long cache_vers;
 318     u_long cache_prog;
 319     struct sockaddr_in cache_addr;
 320     /*
 321      * The cached reply and length
 322      */
 323     char *cache_reply;
 324     u_long cache_replylen;
 325     /*
 326      * Next node on the list, if there is a collision
 327      */
 328     cache_ptr cache_next;
 329   };
 330
 331
 332
 333 /*
 334  * The entire cache
 335  */
 336 struct udp_cache
 337   {
 338     u_long uc_size;             /* size of cache */
 339     cache_ptr *uc_entries;      /* hash table of entries in cache */
 340     cache_ptr *uc_fifo;         /* fifo list of entries in cache */
 341     u_long uc_nextvictim;       /* points to next victim in fifo list */
 342     u_long uc_prog;             /* saved program number */
 343     u_long uc_vers;             /* saved version number */
 344     u_long uc_proc;             /* saved procedure number */
 345     struct sockaddr_in uc_addr; /* saved caller's address */
 346   };
 347
 348
 349 /*
 350  * the hashing function
 351  */
 352 #define CACHE_LOC(transp, xid)  \
 353  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 354
 355
 356 /*
 357  * Enable use of the cache.
 358  * Note: there is no disable.
 359  */
 360 int
 361 svcudp_enablecache (SVCXPRT *transp, u_long size)
 362 {
 363   struct svcudp_data *su = su_data (transp);
 364   struct udp_cache *uc;
 365
 366   if (su->su_cache != NULL)
 367     {
 368       CACHE_PERROR (_("enablecache: cache already enabled"));
 369       return 0;
 370     }
 371   uc = ALLOC (struct udp_cache, 1);
 372   if (uc == NULL)
 373     {
 374       CACHE_PERROR (_("enablecache: could not allocate cache"));
 375       return 0;
 376     }
 377   uc->uc_size = size;
 378   uc->uc_nextvictim = 0;
 379   uc->uc_entries = ALLOC (cache_ptr, size * SPARSENESS);
 380   if (uc->uc_entries == NULL)
 381     {
 382       CACHE_PERROR (_("enablecache: could not allocate cache data"));
 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     {
 389       CACHE_PERROR (_("enablecache: could not allocate cache fifo"));
 390       return 0;
 391     }
 392   BZERO (uc->uc_fifo, cache_ptr, size);
 393   su->su_cache = (char *) uc;
 394   return 1;
 395 }
 396
 397
 398 /*
 399  * Set an entry in the cache
 400  */
 401 static void
 402 cache_set (SVCXPRT *xprt, u_long replylen)
 403 {
 404   cache_ptr victim;
 405   cache_ptr *vicp;
 406   struct svcudp_data *su = su_data (xprt);
 407   struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 408   u_int loc;
 409   char *newbuf;
 410
 411   /*
 412    * Find space for the new entry, either by
 413    * reusing an old entry, or by mallocing a new one
 414    */
 415   victim = uc->uc_fifo[uc->uc_nextvictim];
 416   if (victim != NULL)
 417     {
 418       loc = CACHE_LOC (xprt, victim->cache_xid);
 419       for (vicp = &uc->uc_entries[loc];
 420            *vicp != NULL && *vicp != victim;
 421            vicp = &(*vicp)->cache_next)
 422         ;
 423       if (*vicp == NULL)
 424         {
 425           CACHE_PERROR (_("cache_set: victim not found"));
 426           return;
 427         }
 428       *vicp = victim->cache_next;       /* remote from cache */
 429       newbuf = victim->cache_reply;
 430     }
 431   else
 432     {
 433       victim = ALLOC (struct cache_node, 1);
 434       if (victim == NULL)
 435         {
 436           CACHE_PERROR (_("cache_set: victim alloc failed"));
 437           return;
 438         }
 439       newbuf = mem_alloc (su->su_iosz);
 440       if (newbuf == NULL)
 441         {
 442           CACHE_PERROR (_("cache_set: could not allocate new rpc_buffer"));
 443           return;
 444         }
 445     }
 446
 447   /*
 448    * Store it away
 449    */
 450   victim->cache_replylen = replylen;
 451   victim->cache_reply = rpc_buffer (xprt);
 452   rpc_buffer (xprt) = newbuf;
 453   xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_ENCODE);
 454   victim->cache_xid = su->su_xid;
 455   victim->cache_proc = uc->uc_proc;
 456   victim->cache_vers = uc->uc_vers;
 457   victim->cache_prog = uc->uc_prog;
 458   victim->cache_addr = uc->uc_addr;
 459   loc = CACHE_LOC (xprt, victim->cache_xid);
 460   victim->cache_next = uc->uc_entries[loc];
 461   uc->uc_entries[loc] = victim;
 462   uc->uc_fifo[uc->uc_nextvictim++] = victim;
 463   uc->uc_nextvictim %= uc->uc_size;
 464 }
 465
 466 /*
 467  * Try to get an entry from the cache
 468  * return 1 if found, 0 if not found
 469  */
 470 static int
 471 cache_get (xprt, msg, replyp, replylenp)
 472      SVCXPRT *xprt;
 473      struct rpc_msg *msg;
 474      char **replyp;
 475      u_long *replylenp;
 476 {
 477   u_int loc;
 478   cache_ptr ent;
 479   struct svcudp_data *su = su_data (xprt);
 480   struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 481
 482 #define EQADDR(a1, a2)  (bcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
 483
 484   loc = CACHE_LOC (xprt, su->su_xid);
 485   for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next)
 486     {
 487       if (ent->cache_xid == su->su_xid &&
 488           ent->cache_proc == uc->uc_proc &&
 489           ent->cache_vers == uc->uc_vers &&
 490           ent->cache_prog == uc->uc_prog &&
 491           EQADDR (ent->cache_addr, uc->uc_addr))
 492         {
 493           *replyp = ent->cache_reply;
 494           *replylenp = ent->cache_replylen;
 495           return 1;
 496         }
 497     }
 498   /*
 499    * Failed to find entry
 500    * Remember a few things so we can do a set later
 501    */
 502   uc->uc_proc = msg->rm_call.cb_proc;
 503   uc->uc_vers = msg->rm_call.cb_vers;
 504   uc->uc_prog = msg->rm_call.cb_prog;
 505   uc->uc_addr = xprt->xp_raddr;
 506   return 0;
 507 }