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 #ifdef USE_IN_LIBIO
  50 # include <libio/iolibio.h>
  51 # define fputs(s, f) _IO_fputs (s, f)
  52 #endif
  53
  54 #define rpc_buffer(xprt) ((xprt)->xp_p1)
  55 #ifndef MAX
  56 #define MAX(a, b)     ((a > b) ? a : b)
  57 #endif
  58
  59 static bool_t svcudp_recv (SVCXPRT *, struct rpc_msg *);
  60 static bool_t svcudp_reply (SVCXPRT *, struct rpc_msg *);
  61 static enum xprt_stat svcudp_stat (SVCXPRT *);
  62 static bool_t svcudp_getargs (SVCXPRT *, xdrproc_t, caddr_t);
  63 static bool_t svcudp_freeargs (SVCXPRT *, xdrproc_t, caddr_t);
  64 static void svcudp_destroy (SVCXPRT *);
  65
  66 static const struct xp_ops svcudp_op =
  67 {
  68   svcudp_recv,
  69   svcudp_stat,
  70   svcudp_getargs,
  71   svcudp_reply,
  72   svcudp_freeargs,
  73   svcudp_destroy
  74 };
  75
  76 static int cache_get (SVCXPRT *, struct rpc_msg *, char **replyp,
  77                       u_long *replylenp);
  78 static void cache_set (SVCXPRT *xprt, u_long replylen);
  79
  80 /*
  81  * kept in xprt->xp_p2
  82  */
  83 struct svcudp_data
  84   {
  85     u_int su_iosz;              /* byte size of send.recv buffer */
  86     u_long su_xid;              /* transaction id */
  87     XDR su_xdrs;                /* XDR handle */
  88     char su_verfbody[MAX_AUTH_BYTES];   /* verifier body */
  89     char *su_cache;             /* cached data, NULL if no cache */
  90   };
  91 #define su_data(xprt)   ((struct svcudp_data *)(xprt->xp_p2))
  92
  93 /*
  94  * Usage:
  95  *      xprt = svcudp_create(sock);
  96  *
  97  * If sock<0 then a socket is created, else sock is used.
  98  * If the socket, sock is not bound to a port then svcudp_create
  99  * binds it to an arbitrary port.  In any (successful) case,
 100  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 101  * associated port number.
 102  * Once *xprt is initialized, it is registered as a transporter;
 103  * see (svc.h, xprt_register).
 104  * The routines returns NULL if a problem occurred.
 105  */
 106 SVCXPRT *
 107 svcudp_bufcreate (sock, sendsz, recvsz)
 108      int sock;
 109      u_int sendsz, recvsz;
 110 {
 111   bool_t madesock = FALSE;
 112   SVCXPRT *xprt;
 113   struct svcudp_data *su;
 114   struct sockaddr_in addr;
 115   size_t len = sizeof (struct sockaddr_in);
 116
 117   if (sock == RPC_ANYSOCK)
 118     {
 119       if ((sock = __socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
 120         {
 121           perror (_("svcudp_create: socket creation problem"));
 122           return (SVCXPRT *) NULL;
 123         }
 124       madesock = TRUE;
 125     }
 126   __bzero ((char *) &addr, sizeof (addr));
 127   addr.sin_family = AF_INET;
 128   if (bindresvport (sock, &addr))
 129     {
 130       addr.sin_port = 0;
 131       (void) bind (sock, (struct sockaddr *) &addr, len);
 132     }
 133   if (getsockname (sock, (struct sockaddr *) &addr, &len) != 0)
 134     {
 135       perror (_("svcudp_create - cannot getsockname"));
 136       if (madesock)
 137         (void) __close (sock);
 138       return (SVCXPRT *) NULL;
 139     }
 140   xprt = (SVCXPRT *) mem_alloc (sizeof (SVCXPRT));
 141   if (xprt == NULL)
 142     {
 143       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 144       return NULL;
 145     }
 146   su = (struct svcudp_data *) mem_alloc (sizeof (*su));
 147   if (su == NULL)
 148     {
 149       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 150       return NULL;
 151     }
 152   su->su_iosz = ((MAX (sendsz, recvsz) + 3) / 4) * 4;
 153   if ((rpc_buffer (xprt) = mem_alloc (su->su_iosz)) == NULL)
 154     {
 155       (void) fputs (_("svcudp_create: out of memory\n"), stderr);
 156       return NULL;
 157     }
 158   xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_DECODE);
 159   su->su_cache = NULL;
 160   xprt->xp_p2 = (caddr_t) su;
 161   xprt->xp_verf.oa_base = su->su_verfbody;
 162   xprt->xp_ops = &svcudp_op;
 163   xprt->xp_port = ntohs (addr.sin_port);
 164   xprt->xp_sock = sock;
 165   xprt_register (xprt);
 166   return xprt;
 167 }
 168
 169 SVCXPRT *
 170 svcudp_create (sock)
 171      int sock;
 172 {
 173
 174   return svcudp_bufcreate (sock, UDPMSGSIZE, UDPMSGSIZE);
 175 }
 176
 177 static enum xprt_stat
 178 svcudp_stat (xprt)
 179      SVCXPRT *xprt;
 180 {
 181
 182   return XPRT_IDLE;
 183 }
 184
 185 static bool_t
 186 svcudp_recv (xprt, msg)
 187      SVCXPRT *xprt;
 188      struct rpc_msg *msg;
 189 {
 190   struct svcudp_data *su = su_data (xprt);
 191   XDR *xdrs = &(su->su_xdrs);
 192   int rlen;
 193   char *reply;
 194   u_long replylen;
 195   size_t len;
 196
 197 again:
 198   /* FIXME -- should xp_addrlen be a size_t?  */
 199   len = sizeof(struct sockaddr_in);
 200   rlen = recvfrom (xprt->xp_sock, rpc_buffer (xprt), (int) su->su_iosz, 0,
 201                    (struct sockaddr *) &(xprt->xp_raddr), &len);
 202   xprt->xp_addrlen = len;
 203   if (rlen == -1 && errno == EINTR)
 204     goto again;
 205   if (rlen < 16)                /* < 4 32-bit ints? */
 206     return FALSE;
 207   xdrs->x_op = XDR_DECODE;
 208   XDR_SETPOS (xdrs, 0);
 209   if (!xdr_callmsg (xdrs, msg))
 210     return FALSE;
 211   su->su_xid = msg->rm_xid;
 212   if (su->su_cache != NULL)
 213     {
 214       if (cache_get (xprt, msg, &reply, &replylen))
 215         {
 216           (void) sendto (xprt->xp_sock, reply, (int) replylen, 0,
 217                          (struct sockaddr *) &xprt->xp_raddr, len);
 218           return TRUE;
 219         }
 220     }
 221   return TRUE;
 222 }
 223
 224 static bool_t
 225 svcudp_reply (xprt, msg)
 226      SVCXPRT *xprt;
 227      struct rpc_msg *msg;
 228 {
 229   struct svcudp_data *su = su_data (xprt);
 230   XDR *xdrs = &(su->su_xdrs);
 231   int slen;
 232   bool_t stat = FALSE;
 233
 234   xdrs->x_op = XDR_ENCODE;
 235   XDR_SETPOS (xdrs, 0);
 236   msg->rm_xid = su->su_xid;
 237   if (xdr_replymsg (xdrs, msg))
 238     {
 239       slen = (int) XDR_GETPOS (xdrs);
 240       if (sendto (xprt->xp_sock, rpc_buffer (xprt), slen, 0,
 241                   (struct sockaddr *) &(xprt->xp_raddr), xprt->xp_addrlen)
 242           == slen)
 243         {
 244           stat = TRUE;
 245           if (su->su_cache && slen >= 0)
 246             {
 247               cache_set (xprt, (u_long) slen);
 248             }
 249         }
 250     }
 251   return stat;
 252 }
 253
 254 static bool_t
 255 svcudp_getargs (xprt, xdr_args, args_ptr)
 256      SVCXPRT *xprt;
 257      xdrproc_t xdr_args;
 258      caddr_t args_ptr;
 259 {
 260
 261   return (*xdr_args) (&(su_data (xprt)->su_xdrs), args_ptr);
 262 }
 263
 264 static bool_t
 265 svcudp_freeargs (xprt, xdr_args, args_ptr)
 266      SVCXPRT *xprt;
 267      xdrproc_t xdr_args;
 268      caddr_t args_ptr;
 269 {
 270   XDR *xdrs = &(su_data (xprt)->su_xdrs);
 271
 272   xdrs->x_op = XDR_FREE;
 273   return (*xdr_args) (xdrs, args_ptr);
 274 }
 275
 276 static void
 277 svcudp_destroy (xprt)
 278      SVCXPRT *xprt;
 279 {
 280   struct svcudp_data *su = su_data (xprt);
 281
 282   xprt_unregister (xprt);
 283   (void) __close (xprt->xp_sock);
 284   XDR_DESTROY (&(su->su_xdrs));
 285   mem_free (rpc_buffer (xprt), su->su_iosz);
 286   mem_free ((caddr_t) su, sizeof (struct svcudp_data));
 287   mem_free ((caddr_t) xprt, sizeof (SVCXPRT));
 288 }
 289
 290
 291 /***********this could be a separate file*********************/
 292
 293 /*
 294  * Fifo cache for udp server
 295  * Copies pointers to reply buffers into fifo cache
 296  * Buffers are sent again if retransmissions are detected.
 297  */
 298
 299 #define SPARSENESS 4            /* 75% sparse */
 300
 301 #define CACHE_PERROR(msg)       \
 302         (void) fprintf(stderr,"%s\n", msg)
 303
 304 #define ALLOC(type, size)       \
 305         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 306
 307 #define BZERO(addr, type, size)  \
 308         __bzero((char *) addr, sizeof(type) * (int) (size))
 309
 310 /*
 311  * An entry in the cache
 312  */
 313 typedef struct cache_node *cache_ptr;
 314 struct cache_node
 315   {
 316     /*
 317      * Index into cache is xid, proc, vers, prog and address
 318      */
 319     u_long cache_xid;
 320     u_long cache_proc;
 321     u_long cache_vers;
 322     u_long cache_prog;
 323     struct sockaddr_in cache_addr;
 324     /*
 325      * The cached reply and length
 326      */
 327     char *cache_reply;
 328     u_long cache_replylen;
 329     /*
 330      * Next node on the list, if there is a collision
 331      */
 332     cache_ptr cache_next;
 333   };
 334
 335
 336
 337 /*
 338  * The entire cache
 339  */
 340 struct udp_cache
 341   {
 342     u_long uc_size;             /* size of cache */
 343     cache_ptr *uc_entries;      /* hash table of entries in cache */
 344     cache_ptr *uc_fifo;         /* fifo list of entries in cache */
 345     u_long uc_nextvictim;       /* points to next victim in fifo list */
 346     u_long uc_prog;             /* saved program number */
 347     u_long uc_vers;             /* saved version number */
 348     u_long uc_proc;             /* saved procedure number */
 349     struct sockaddr_in uc_addr; /* saved caller's address */
 350   };
 351
 352
 353 /*
 354  * the hashing function
 355  */
 356 #define CACHE_LOC(transp, xid)  \
 357  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 358
 359
 360 /*
 361  * Enable use of the cache.
 362  * Note: there is no disable.
 363  */
 364 int
 365 svcudp_enablecache (SVCXPRT *transp, u_long size)
 366 {
 367   struct svcudp_data *su = su_data (transp);
 368   struct udp_cache *uc;
 369
 370   if (su->su_cache != NULL)
 371     {
 372       CACHE_PERROR (_("enablecache: cache already enabled"));
 373       return 0;
 374     }
 375   uc = ALLOC (struct udp_cache, 1);
 376   if (uc == NULL)
 377     {
 378       CACHE_PERROR (_("enablecache: could not allocate cache"));
 379       return 0;
 380     }
 381   uc->uc_size = size;
 382   uc->uc_nextvictim = 0;
 383   uc->uc_entries = ALLOC (cache_ptr, size * SPARSENESS);
 384   if (uc->uc_entries == NULL)
 385     {
 386       CACHE_PERROR (_("enablecache: could not allocate cache data"));
 387       return 0;
 388     }
 389   BZERO (uc->uc_entries, cache_ptr, size * SPARSENESS);
 390   uc->uc_fifo = ALLOC (cache_ptr, size);
 391   if (uc->uc_fifo == NULL)
 392     {
 393       CACHE_PERROR (_("enablecache: could not allocate cache fifo"));
 394       return 0;
 395     }
 396   BZERO (uc->uc_fifo, cache_ptr, size);
 397   su->su_cache = (char *) uc;
 398   return 1;
 399 }
 400
 401
 402 /*
 403  * Set an entry in the cache
 404  */
 405 static void
 406 cache_set (SVCXPRT *xprt, u_long replylen)
 407 {
 408   cache_ptr victim;
 409   cache_ptr *vicp;
 410   struct svcudp_data *su = su_data (xprt);
 411   struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 412   u_int loc;
 413   char *newbuf;
 414
 415   /*
 416    * Find space for the new entry, either by
 417    * reusing an old entry, or by mallocing a new one
 418    */
 419   victim = uc->uc_fifo[uc->uc_nextvictim];
 420   if (victim != NULL)
 421     {
 422       loc = CACHE_LOC (xprt, victim->cache_xid);
 423       for (vicp = &uc->uc_entries[loc];
 424            *vicp != NULL && *vicp != victim;
 425            vicp = &(*vicp)->cache_next)
 426         ;
 427       if (*vicp == NULL)
 428         {
 429           CACHE_PERROR (_("cache_set: victim not found"));
 430           return;
 431         }
 432       *vicp = victim->cache_next;       /* remote from cache */
 433       newbuf = victim->cache_reply;
 434     }
 435   else
 436     {
 437       victim = ALLOC (struct cache_node, 1);
 438       if (victim == NULL)
 439         {
 440           CACHE_PERROR (_("cache_set: victim alloc failed"));
 441           return;
 442         }
 443       newbuf = mem_alloc (su->su_iosz);
 444       if (newbuf == NULL)
 445         {
 446           CACHE_PERROR (_("cache_set: could not allocate new rpc_buffer"));
 447           return;
 448         }
 449     }
 450
 451   /*
 452    * Store it away
 453    */
 454   victim->cache_replylen = replylen;
 455   victim->cache_reply = rpc_buffer (xprt);
 456   rpc_buffer (xprt) = newbuf;
 457   xdrmem_create (&(su->su_xdrs), rpc_buffer (xprt), su->su_iosz, XDR_ENCODE);
 458   victim->cache_xid = su->su_xid;
 459   victim->cache_proc = uc->uc_proc;
 460   victim->cache_vers = uc->uc_vers;
 461   victim->cache_prog = uc->uc_prog;
 462   victim->cache_addr = uc->uc_addr;
 463   loc = CACHE_LOC (xprt, victim->cache_xid);
 464   victim->cache_next = uc->uc_entries[loc];
 465   uc->uc_entries[loc] = victim;
 466   uc->uc_fifo[uc->uc_nextvictim++] = victim;
 467   uc->uc_nextvictim %= uc->uc_size;
 468 }
 469
 470 /*
 471  * Try to get an entry from the cache
 472  * return 1 if found, 0 if not found
 473  */
 474 static int
 475 cache_get (xprt, msg, replyp, replylenp)
 476      SVCXPRT *xprt;
 477      struct rpc_msg *msg;
 478      char **replyp;
 479      u_long *replylenp;
 480 {
 481   u_int loc;
 482   cache_ptr ent;
 483   struct svcudp_data *su = su_data (xprt);
 484   struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 485
 486 #define EQADDR(a1, a2)  (memcmp((char*)&a1, (char*)&a2, sizeof(a1)) == 0)
 487
 488   loc = CACHE_LOC (xprt, su->su_xid);
 489   for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next)
 490     {
 491       if (ent->cache_xid == su->su_xid &&
 492           ent->cache_proc == uc->uc_proc &&
 493           ent->cache_vers == uc->uc_vers &&
 494           ent->cache_prog == uc->uc_prog &&
 495           EQADDR (ent->cache_addr, uc->uc_addr))
 496         {
 497           *replyp = ent->cache_reply;
 498           *replylenp = ent->cache_replylen;
 499           return 1;
 500         }
 501     }
 502   /*
 503    * Failed to find entry
 504    * Remember a few things so we can do a set later
 505    */
 506   uc->uc_proc = msg->rm_call.cb_proc;
 507   uc->uc_vers = msg->rm_call.cb_vers;
 508   uc->uc_prog = msg->rm_call.cb_prog;
 509   uc->uc_addr = xprt->xp_raddr;
 510   return 0;
 511 }