lib/libc/rpc/svc_udp.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  *
  29  * @(#)svc_udp.c 1.24 87/08/11 Copyr 1984 Sun Micro
  30  * @(#)svc_udp.c        2.2 88/07/29 4.0 RPCSRC
  31  * $FreeBSD: src/lib/libc/rpc/svc_udp.c,v 1.13 2000/01/27 23:06:41 jasone Exp $
  32  * $DragonFly: src/lib/libc/rpc/svc_udp.c,v 1.6 2005/11/13 12:27:04 swildner Exp $
  33  */
  34
  35 /*
  36  * svc_udp.c,
  37  * Server side for UDP/IP based RPC.  (Does some caching in the hopes of
  38  * achieving execute-at-most-once semantics.)
  39  *
  40  * Copyright (C) 1984, Sun Microsystems, Inc.
  41  */
  42
  43 #include "namespace.h"
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <unistd.h>
  47 #include <string.h>
  48 #include <rpc/rpc.h>
  49 #include <sys/socket.h>
  50 #include <errno.h>
  51 #include "un-namespace.h"
  52
  53 #define rpc_buffer(xprt) ((xprt)->xp_p1)
  54 #define MAX(a, b)     ((a > b) ? a : b)
  55
  56 static bool_t           svcudp_recv();
  57 static bool_t           svcudp_reply();
  58 static enum xprt_stat   svcudp_stat();
  59 static bool_t           svcudp_getargs();
  60 static bool_t           svcudp_freeargs();
  61 static void             svcudp_destroy();
  62 static void             cache_set (SVCXPRT *, u_long);
  63 static int              cache_get (SVCXPRT *, struct rpc_msg *, char **, u_long *);
  64
  65 static struct xp_ops svcudp_op = {
  66         svcudp_recv,
  67         svcudp_stat,
  68         svcudp_getargs,
  69         svcudp_reply,
  70         svcudp_freeargs,
  71         svcudp_destroy
  72 };
  73
  74 /*
  75  * kept in xprt->xp_p2
  76  */
  77 struct svcudp_data {
  78         u_int   su_iosz;        /* byte size of send.recv buffer */
  79         u_long  su_xid;         /* transaction id */
  80         XDR     su_xdrs;        /* XDR handle */
  81         char    su_verfbody[MAX_AUTH_BYTES];    /* verifier body */
  82         char *  su_cache;       /* cached data, NULL if no cache */
  83 };
  84 #define su_data(xprt)   ((struct svcudp_data *)(xprt->xp_p2))
  85
  86 /*
  87  * Usage:
  88  *      xprt = svcudp_create(sock);
  89  *
  90  * If sock<0 then a socket is created, else sock is used.
  91  * If the socket, sock is not bound to a port then svcudp_create
  92  * binds it to an arbitrary port.  In any (successful) case,
  93  * xprt->xp_sock is the registered socket number and xprt->xp_port is the
  94  * associated port number.
  95  * Once *xprt is initialized, it is registered as a transporter;
  96  * see (svc.h, xprt_register).
  97  * The routines returns NULL if a problem occurred.
  98  */
  99 SVCXPRT *
 100 svcudp_bufcreate(int sock, u_int sendsz, u_int recvsz)
 101 {
 102         bool_t madesock = FALSE;
 103         SVCXPRT *xprt;
 104         struct svcudp_data *su;
 105         struct sockaddr_in addr;
 106         int len = sizeof(struct sockaddr_in);
 107
 108         if (sock == RPC_ANYSOCK) {
 109                 if ((sock = _socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
 110                         perror("svcudp_create: socket creation problem");
 111                         return ((SVCXPRT *)NULL);
 112                 }
 113                 madesock = TRUE;
 114         }
 115         memset((char *)&addr, 0, sizeof (addr));
 116         addr.sin_len = sizeof(struct sockaddr_in);
 117         addr.sin_family = AF_INET;
 118         if (bindresvport(sock, &addr)) {
 119                 addr.sin_port = 0;
 120                 _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                         _close(sock);
 126                 return ((SVCXPRT *)NULL);
 127         }
 128         xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
 129         if (xprt == NULL) {
 130                 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                 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                 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(int sock)
 157 {
 158
 159         return(svcudp_bufcreate(sock, UDPMSGSIZE, UDPMSGSIZE));
 160 }
 161
 162 static enum xprt_stat
 163 svcudp_stat(SVCXPRT *xprt)
 164 {
 165
 166         return (XPRT_IDLE);
 167 }
 168
 169 static bool_t
 170 svcudp_recv(SVCXPRT *xprt, struct rpc_msg *msg)
 171 {
 172         struct svcudp_data *su = su_data(xprt);
 173         XDR *xdrs = &(su->su_xdrs);
 174         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 == -1 || rlen < 4*sizeof(u_int32_t))
 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                         _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(SVCXPRT *xprt, struct rpc_msg *msg)
 203 {
 204         struct svcudp_data *su = su_data(xprt);
 205         XDR *xdrs = &(su->su_xdrs);
 206         int slen;
 207         bool_t stat = FALSE;
 208
 209         xdrs->x_op = XDR_ENCODE;
 210         XDR_SETPOS(xdrs, 0);
 211         msg->rm_xid = su->su_xid;
 212         if (xdr_replymsg(xdrs, msg)) {
 213                 slen = (int)XDR_GETPOS(xdrs);
 214                 if (_sendto(xprt->xp_sock, rpc_buffer(xprt), slen, 0,
 215                     (struct sockaddr *)&(xprt->xp_raddr), xprt->xp_addrlen)
 216                     == slen) {
 217                         stat = TRUE;
 218                         if (su->su_cache && slen >= 0) {
 219                                 cache_set(xprt, (u_long) slen);
 220                         }
 221                 }
 222         }
 223         return (stat);
 224 }
 225
 226 static bool_t
 227 svcudp_getargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 228 {
 229
 230         return ((*xdr_args)(&(su_data(xprt)->su_xdrs), args_ptr));
 231 }
 232
 233 static bool_t
 234 svcudp_freeargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr)
 235 {
 236         XDR *xdrs = &(su_data(xprt)->su_xdrs);
 237
 238         xdrs->x_op = XDR_FREE;
 239         return ((*xdr_args)(xdrs, args_ptr));
 240 }
 241
 242 static void
 243 svcudp_destroy(SVCXPRT *xprt)
 244 {
 245         struct svcudp_data *su = su_data(xprt);
 246
 247         xprt_unregister(xprt);
 248         _close(xprt->xp_sock);
 249         XDR_DESTROY(&(su->su_xdrs));
 250         mem_free(rpc_buffer(xprt), su->su_iosz);
 251         mem_free((caddr_t)su, sizeof(struct svcudp_data));
 252         mem_free((caddr_t)xprt, sizeof(SVCXPRT));
 253 }
 254
 255
 256 /***********this could be a separate file*********************/
 257
 258 /*
 259  * Fifo cache for udp server
 260  * Copies pointers to reply buffers into fifo cache
 261  * Buffers are sent again if retransmissions are detected.
 262  */
 263
 264 #define SPARSENESS 4    /* 75% sparse */
 265
 266 #define CACHE_PERROR(msg)       \
 267         fprintf(stderr,"%s\n", msg)
 268
 269 #define ALLOC(type, size)       \
 270         (type *) mem_alloc((unsigned) (sizeof(type) * (size)))
 271
 272 #define BZERO(addr, type, size)  \
 273         memset((char *) addr, 0, sizeof(type) * (int) (size))
 274
 275 /*
 276  * An entry in the cache
 277  */
 278 typedef struct cache_node *cache_ptr;
 279 struct cache_node {
 280         /*
 281          * Index into cache is xid, proc, vers, prog and address
 282          */
 283         u_long cache_xid;
 284         u_long cache_proc;
 285         u_long cache_vers;
 286         u_long cache_prog;
 287         struct sockaddr_in cache_addr;
 288         /*
 289          * The cached reply and length
 290          */
 291         char * cache_reply;
 292         u_long cache_replylen;
 293         /*
 294          * Next node on the list, if there is a collision
 295          */
 296         cache_ptr cache_next;
 297 };
 298
 299
 300
 301 /*
 302  * The entire cache
 303  */
 304 struct udp_cache {
 305         u_long uc_size;         /* size of cache */
 306         cache_ptr *uc_entries;  /* hash table of entries in cache */
 307         cache_ptr *uc_fifo;     /* fifo list of entries in cache */
 308         u_long uc_nextvictim;   /* points to next victim in fifo list */
 309         u_long uc_prog;         /* saved program number */
 310         u_long uc_vers;         /* saved version number */
 311         u_long uc_proc;         /* saved procedure number */
 312         struct sockaddr_in uc_addr; /* saved caller's address */
 313 };
 314
 315
 316 /*
 317  * the hashing function
 318  */
 319 #define CACHE_LOC(transp, xid)  \
 320  (xid % (SPARSENESS*((struct udp_cache *) su_data(transp)->su_cache)->uc_size))
 321
 322
 323 /*
 324  * Enable use of the cache.
 325  * Note: there is no disable.
 326  */
 327 int
 328 svcudp_enablecache(SVCXPRT *transp, u_long size)
 329 {
 330         struct svcudp_data *su = su_data(transp);
 331         struct udp_cache *uc;
 332
 333         if (su->su_cache != NULL) {
 334                 CACHE_PERROR("enablecache: cache already enabled");
 335                 return(0);
 336         }
 337         uc = ALLOC(struct udp_cache, 1);
 338         if (uc == NULL) {
 339                 CACHE_PERROR("enablecache: could not allocate cache");
 340                 return(0);
 341         }
 342         uc->uc_size = size;
 343         uc->uc_nextvictim = 0;
 344         uc->uc_entries = ALLOC(cache_ptr, size * SPARSENESS);
 345         if (uc->uc_entries == NULL) {
 346                 CACHE_PERROR("enablecache: could not allocate cache data");
 347                 return(0);
 348         }
 349         BZERO(uc->uc_entries, cache_ptr, size * SPARSENESS);
 350         uc->uc_fifo = ALLOC(cache_ptr, size);
 351         if (uc->uc_fifo == NULL) {
 352                 CACHE_PERROR("enablecache: could not allocate cache fifo");
 353                 return(0);
 354         }
 355         BZERO(uc->uc_fifo, cache_ptr, size);
 356         su->su_cache = (char *) uc;
 357         return(1);
 358 }
 359
 360
 361 /*
 362  * Set an entry in the cache
 363  */
 364 static void
 365 cache_set(SVCXPRT *xprt, u_long replylen)
 366 {
 367         cache_ptr victim;
 368         cache_ptr *vicp;
 369         struct svcudp_data *su = su_data(xprt);
 370         struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 371         u_int loc;
 372         char *newbuf;
 373
 374         /*
 375          * Find space for the new entry, either by
 376          * reusing an old entry, or by mallocing a new one
 377          */
 378         victim = uc->uc_fifo[uc->uc_nextvictim];
 379         if (victim != NULL) {
 380                 loc = CACHE_LOC(xprt, victim->cache_xid);
 381                 for (vicp = &uc->uc_entries[loc];
 382                   *vicp != NULL && *vicp != victim;
 383                   vicp = &(*vicp)->cache_next)
 384                                 ;
 385                 if (*vicp == NULL) {
 386                         CACHE_PERROR("cache_set: victim not found");
 387                         return;
 388                 }
 389                 *vicp = victim->cache_next;     /* remote from cache */
 390                 newbuf = victim->cache_reply;
 391         } else {
 392                 victim = ALLOC(struct cache_node, 1);
 393                 if (victim == NULL) {
 394                         CACHE_PERROR("cache_set: victim alloc failed");
 395                         return;
 396                 }
 397                 newbuf = mem_alloc(su->su_iosz);
 398                 if (newbuf == NULL) {
 399                         CACHE_PERROR("cache_set: could not allocate new rpc_buffer");
 400                         return;
 401                 }
 402         }
 403
 404         /*
 405          * Store it away
 406          */
 407         victim->cache_replylen = replylen;
 408         victim->cache_reply = rpc_buffer(xprt);
 409         rpc_buffer(xprt) = newbuf;
 410         xdrmem_create(&(su->su_xdrs), rpc_buffer(xprt), su->su_iosz, XDR_ENCODE);
 411         victim->cache_xid = su->su_xid;
 412         victim->cache_proc = uc->uc_proc;
 413         victim->cache_vers = uc->uc_vers;
 414         victim->cache_prog = uc->uc_prog;
 415         victim->cache_addr = uc->uc_addr;
 416         loc = CACHE_LOC(xprt, victim->cache_xid);
 417         victim->cache_next = uc->uc_entries[loc];
 418         uc->uc_entries[loc] = victim;
 419         uc->uc_fifo[uc->uc_nextvictim++] = victim;
 420         uc->uc_nextvictim %= uc->uc_size;
 421 }
 422
 423 /*
 424  * Try to get an entry from the cache
 425  * return 1 if found, 0 if not found
 426  */
 427 static int
 428 cache_get(SVCXPRT *xprt, struct rpc_msg *msg, char **replyp, u_long *replylenp)
 429 {
 430         u_int loc;
 431         cache_ptr ent;
 432         struct svcudp_data *su = su_data(xprt);
 433         struct udp_cache *uc = (struct udp_cache *) su->su_cache;
 434
 435 #       define EQADDR(a1, a2)   (memcmp(&a1, &a2, sizeof(a1)) == 0)
 436
 437         loc = CACHE_LOC(xprt, su->su_xid);
 438         for (ent = uc->uc_entries[loc]; ent != NULL; ent = ent->cache_next) {
 439                 if (ent->cache_xid == su->su_xid &&
 440                   ent->cache_proc == uc->uc_proc &&
 441                   ent->cache_vers == uc->uc_vers &&
 442                   ent->cache_prog == uc->uc_prog &&
 443                   EQADDR(ent->cache_addr, uc->uc_addr)) {
 444                         *replyp = ent->cache_reply;
 445                         *replylenp = ent->cache_replylen;
 446                         return(1);
 447                 }
 448         }
 449         /*
 450          * Failed to find entry
 451          * Remember a few things so we can do a set later
 452          */
 453         uc->uc_proc = msg->rm_call.cb_proc;
 454         uc->uc_vers = msg->rm_call.cb_vers;
 455         uc->uc_prog = msg->rm_call.cb_prog;
 456         uc->uc_addr = xprt->xp_raddr;
 457         return(0);
 458 }
 459