nis/nis_findserv.c

   1 /* Copyright (C) 1997, 1998, 2000, 2001, 2010 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1997.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <string.h>
  21 #include <time.h>
  22 #include <unistd.h>
  23 #include <sys/ioctl.h>
  24 #include <sys/socket.h>
  25 #include <rpc/pmap_prot.h>
  26 #include <rpc/pmap_clnt.h>
  27 #include <rpcsvc/nis.h>
  28
  29 #include "nis_intern.h"
  30
  31 /* Private data kept per client handle, from sunrpc/clnt_udp.c */
  32 struct cu_data
  33   {
  34     int cu_sock;
  35     bool_t cu_closeit;
  36     struct sockaddr_in cu_raddr;
  37     int cu_rlen;
  38     struct timeval cu_wait;
  39     struct timeval cu_total;
  40     struct rpc_err cu_error;
  41     XDR cu_outxdrs;
  42     u_int cu_xdrpos;
  43     u_int cu_sendsz;
  44     char *cu_outbuf;
  45     u_int cu_recvsz;
  46     char cu_inbuf[1];
  47   };
  48
  49
  50 /*
  51  * Find the mapped port for program,version.
  52  * Calls the pmap service remotely to do the lookup.
  53  * Returns 0 if no map exists.
  54  */
  55 u_short
  56 __pmap_getnisport (struct sockaddr_in *address, u_long program,
  57                    u_long version, u_int protocol)
  58 {
  59   return __libc_rpc_getport (address, program, version, protocol, 1, 1);
  60 }
  61
  62 /* This is now the public function, which should find the fastest server */
  63
  64 struct findserv_req
  65 {
  66   struct sockaddr_in sin;
  67   u_int32_t xid;
  68   u_int server_nr;
  69   u_int server_ep;
  70 };
  71
  72
  73 static long int
  74 __nis_findfastest_with_timeout (dir_binding *bind,
  75                                 const struct timeval *timeout)
  76 {
  77   static const struct timeval TIMEOUT00 = { 0, 0 };
  78   struct findserv_req *pings;
  79   struct sockaddr_in sin, saved_sin;
  80   int found = -1;
  81   u_int32_t xid_seed;
  82   int sock, dontblock = 1;
  83   CLIENT *clnt;
  84   u_long i, j, pings_count, pings_max, fastest = -1;
  85   struct cu_data *cu;
  86
  87   pings_max = bind->server_len * 2;     /* Reserve a little bit more memory
  88                                            for multihomed hosts */
  89   pings_count = 0;
  90   pings = malloc (sizeof (struct findserv_req) * pings_max);
  91   xid_seed = (u_int32_t) (time (NULL) ^ getpid ());
  92
  93   if (__builtin_expect (pings == NULL, 0))
  94     return -1;
  95
  96   memset (&sin, '\0', sizeof (sin));
  97   sin.sin_family = AF_INET;
  98   for (i = 0; i < bind->server_len; i++)
  99     for (j = 0; j < bind->server_val[i].ep.ep_len; ++j)
 100       if (strcmp (bind->server_val[i].ep.ep_val[j].family, "inet") == 0)
 101         if ((bind->server_val[i].ep.ep_val[j].proto == NULL) ||
 102             (bind->server_val[i].ep.ep_val[j].proto[0] == '-') ||
 103             (bind->server_val[i].ep.ep_val[j].proto[0] == '\0'))
 104           {
 105             sin.sin_addr.s_addr =
 106               inetstr2int (bind->server_val[i].ep.ep_val[j].uaddr);
 107             if (sin.sin_addr.s_addr == 0)
 108               continue;
 109             sin.sin_port = htons (__pmap_getnisport (&sin, NIS_PROG,
 110                                                      NIS_VERSION,
 111                                                      IPPROTO_UDP));
 112             if (sin.sin_port == 0)
 113               continue;
 114
 115             if (pings_count >= pings_max)
 116               {
 117                 struct findserv_req *new_pings;
 118
 119                 pings_max += 10;
 120                 new_pings = realloc (pings, sizeof (struct findserv_req) *
 121                                      pings_max);
 122                 if (__builtin_expect (new_pings == NULL, 0))
 123                   {
 124                     free (pings);
 125                     return -1;
 126                   }
 127                 pings = new_pings;
 128               }
 129             memcpy ((char *) &pings[pings_count].sin, (char *) &sin,
 130                     sizeof (sin));
 131             memcpy ((char *)&saved_sin, (char *)&sin, sizeof(sin));
 132             pings[pings_count].xid = xid_seed + pings_count;
 133             pings[pings_count].server_nr = i;
 134             pings[pings_count].server_ep = j;
 135             ++pings_count;
 136           }
 137
 138   /* Make sure at least one server was assigned */
 139   if (pings_count == 0)
 140     {
 141       free (pings);
 142       return -1;
 143     }
 144
 145   /* Create RPC handle */
 146   sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 147   clnt = clntudp_create (&saved_sin, NIS_PROG, NIS_VERSION, *timeout, &sock);
 148   if (clnt == NULL)
 149     {
 150       close (sock);
 151       free (pings);
 152       return -1;
 153     }
 154   auth_destroy (clnt->cl_auth);
 155   clnt->cl_auth = authunix_create_default ();
 156   cu = (struct cu_data *) clnt->cl_private;
 157   ioctl (sock, FIONBIO, &dontblock);
 158   /* Send to all servers the NULLPROC */
 159   for (i = 0; i < pings_count; ++i)
 160     {
 161       /* clntudp_call() will increment, subtract one */
 162       *((u_int32_t *) (cu->cu_outbuf)) = pings[i].xid - 1;
 163       memcpy ((char *) &cu->cu_raddr, (char *) &pings[i].sin,
 164               sizeof (struct sockaddr_in));
 165       /* Transmit to NULLPROC, return immediately. */
 166       clnt_call (clnt, NULLPROC,
 167                  (xdrproc_t) xdr_void, (caddr_t) 0,
 168                  (xdrproc_t) xdr_void, (caddr_t) 0, TIMEOUT00);
 169     }
 170
 171   while (found == -1) {
 172     /* Receive reply from NULLPROC asynchronously. Note null inproc. */
 173     int rc = clnt_call (clnt, NULLPROC,
 174                         (xdrproc_t) NULL, (caddr_t) 0,
 175                         (xdrproc_t) xdr_void, (caddr_t) 0,
 176                         *timeout);
 177     if (RPC_SUCCESS == rc) {
 178       fastest = *((u_int32_t *) (cu->cu_inbuf)) - xid_seed;
 179       if (fastest < pings_count) {
 180         bind->server_used = pings[fastest].server_nr;
 181         bind->current_ep = pings[fastest].server_ep;
 182         found = 1;
 183       }
 184     } else {
 185       /*      clnt_perror(clnt, "__nis_findfastest"); */
 186       break;
 187     }
 188   }
 189
 190
 191   auth_destroy (clnt->cl_auth);
 192   clnt_destroy (clnt);
 193   close (sock);
 194
 195   free (pings);
 196
 197   return found;
 198 }
 199
 200
 201 long int
 202 __nis_findfastest (dir_binding *bind)
 203 {
 204   struct timeval timeout = { __NIS_PING_TIMEOUT_START, 0 };
 205   long int found = -1;
 206   long int retry = __NIS_PING_RETRY + 1;
 207
 208   while (retry--)
 209     {
 210       found = __nis_findfastest_with_timeout (bind, &timeout);
 211       if (found != -1)
 212         break;
 213       timeout.tv_sec += __NIS_PING_TIMEOUT_INCREMENT;
 214     }
 215
 216   return found;
 217 }