nis/nis_findserv.c

   1 /* Copyright (C) 1997-2020 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, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <string.h>
  20 #include <time.h>
  21 #include <unistd.h>
  22 #include <sys/ioctl.h>
  23 #include <sys/socket.h>
  24 #include <rpc/pmap_prot.h>
  25 #include <rpc/pmap_clnt.h>
  26 #include <rpcsvc/nis.h>
  27
  28 #include "nis_intern.h"
  29
  30 /* Private data kept per client handle, from sunrpc/clnt_udp.c */
  31 struct cu_data
  32   {
  33     int cu_sock;
  34     bool_t cu_closeit;
  35     struct sockaddr_in cu_raddr;
  36     int cu_rlen;
  37     struct timeval cu_wait;
  38     struct timeval cu_total;
  39     struct rpc_err cu_error;
  40     XDR cu_outxdrs;
  41     u_int cu_xdrpos;
  42     u_int cu_sendsz;
  43     char *cu_outbuf;
  44     u_int cu_recvsz;
  45     char cu_inbuf[1];
  46   };
  47
  48
  49 /*
  50  * Find the mapped port for program,version.
  51  * Calls the pmap service remotely to do the lookup.
  52  * Returns 0 if no map exists.
  53  */
  54 u_short
  55 __pmap_getnisport (struct sockaddr_in *address, u_long program,
  56                    u_long version, u_int protocol)
  57 {
  58   return __libc_rpc_getport (address, program, version, protocol, 1, 1);
  59 }
  60
  61 /* This is now the public function, which should find the fastest server */
  62
  63 struct findserv_req
  64 {
  65   struct sockaddr_in sin;
  66   uint32_t xid;
  67   u_int server_nr;
  68   u_int server_ep;
  69 };
  70
  71
  72 static long int
  73 __nis_findfastest_with_timeout (dir_binding *bind,
  74                                 const struct timeval *timeout)
  75 {
  76   static const struct timeval TIMEOUT00 = { 0, 0 };
  77   struct findserv_req *pings;
  78   struct sockaddr_in sin, saved_sin;
  79   int found = -1;
  80   uint32_t xid_seed;
  81   int sock, dontblock = 1;
  82   CLIENT *clnt;
  83   u_long i, j, pings_count, pings_max, fastest = -1;
  84   struct cu_data *cu;
  85
  86   pings_max = bind->server_len * 2;     /* Reserve a little bit more memory
  87                                            for multihomed hosts */
  88   pings_count = 0;
  89   pings = malloc (sizeof (struct findserv_req) * pings_max);
  90   xid_seed = (uint32_t) (time (NULL) ^ getpid ());
  91
  92   if (__glibc_unlikely (pings == NULL))
  93     return -1;
  94
  95   memset (&sin, '\0', sizeof (sin));
  96   sin.sin_family = AF_INET;
  97   for (i = 0; i < bind->server_len; i++)
  98     for (j = 0; j < bind->server_val[i].ep.ep_len; ++j)
  99       if (strcmp (bind->server_val[i].ep.ep_val[j].family, "inet") == 0)
 100         if ((bind->server_val[i].ep.ep_val[j].proto == NULL)
 101             || (bind->server_val[i].ep.ep_val[j].proto[0] == '-')
 102             || (bind->server_val[i].ep.ep_val[j].proto[0] == '\0'))
 103           {
 104             sin.sin_addr.s_addr =
 105               inetstr2int (bind->server_val[i].ep.ep_val[j].uaddr);
 106             if (sin.sin_addr.s_addr == 0)
 107               continue;
 108             sin.sin_port = htons (__pmap_getnisport (&sin, NIS_PROG,
 109                                                      NIS_VERSION,
 110                                                      IPPROTO_UDP));
 111             if (sin.sin_port == 0)
 112               continue;
 113
 114             if (pings_count >= pings_max)
 115               {
 116                 struct findserv_req *new_pings;
 117
 118                 pings_max += 10;
 119                 new_pings = realloc (pings, sizeof (struct findserv_req) *
 120                                      pings_max);
 121                 if (__glibc_unlikely (new_pings == NULL))
 122                   {
 123                     free (pings);
 124                     return -1;
 125                   }
 126                 pings = new_pings;
 127               }
 128             memcpy ((char *) &pings[pings_count].sin, (char *) &sin,
 129                     sizeof (sin));
 130             memcpy ((char *)&saved_sin, (char *)&sin, sizeof (sin));
 131             pings[pings_count].xid = xid_seed + pings_count;
 132             pings[pings_count].server_nr = i;
 133             pings[pings_count].server_ep = j;
 134             ++pings_count;
 135           }
 136
 137   /* Make sure at least one server was assigned */
 138   if (pings_count == 0)
 139     {
 140       free (pings);
 141       return -1;
 142     }
 143
 144   /* Create RPC handle */
 145   sock = socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
 146   clnt = clntudp_create (&saved_sin, NIS_PROG, NIS_VERSION, *timeout, &sock);
 147   if (clnt == NULL)
 148     {
 149       close (sock);
 150       free (pings);
 151       return -1;
 152     }
 153   auth_destroy (clnt->cl_auth);
 154   clnt->cl_auth = authunix_create_default ();
 155   cu = (struct cu_data *) clnt->cl_private;
 156   ioctl (sock, FIONBIO, &dontblock);
 157   /* Send to all servers the NULLPROC */
 158   for (i = 0; i < pings_count; ++i)
 159     {
 160       /* clntudp_call() will increment, subtract one */
 161       *((uint32_t *) (cu->cu_outbuf)) = pings[i].xid - 1;
 162       memcpy ((char *) &cu->cu_raddr, (char *) &pings[i].sin,
 163               sizeof (struct sockaddr_in));
 164       /* Transmit to NULLPROC, return immediately. */
 165       clnt_call (clnt, NULLPROC,
 166                  (xdrproc_t) xdr_void, (caddr_t) 0,
 167                  (xdrproc_t) xdr_void, (caddr_t) 0, TIMEOUT00);
 168     }
 169
 170   while (found == -1) {
 171     /* Receive reply from NULLPROC asynchronously. Note null inproc. */
 172     int rc = clnt_call (clnt, NULLPROC,
 173                         (xdrproc_t) NULL, (caddr_t) 0,
 174                         (xdrproc_t) xdr_void, (caddr_t) 0,
 175                         *timeout);
 176     if (RPC_SUCCESS == rc) {
 177       uint32_t val;
 178       memcpy (&val, cu->cu_inbuf, sizeof (uint32_t));
 179       fastest = val - xid_seed;
 180       if (fastest < pings_count) {
 181         bind->server_used = pings[fastest].server_nr;
 182         bind->current_ep = pings[fastest].server_ep;
 183         found = 1;
 184       }
 185     } else {
 186       /*      clnt_perror(clnt, "__nis_findfastest"); */
 187       break;
 188     }
 189   }
 190
 191
 192   auth_destroy (clnt->cl_auth);
 193   clnt_destroy (clnt);
 194   close (sock);
 195
 196   free (pings);
 197
 198   return found;
 199 }
 200
 201
 202 long int
 203 __nis_findfastest (dir_binding *bind)
 204 {
 205   struct timeval timeout = { __NIS_PING_TIMEOUT_START, 0 };
 206   long int found = -1;
 207   long int retry = __NIS_PING_RETRY + 1;
 208
 209   while (retry--)
 210     {
 211       found = __nis_findfastest_with_timeout (bind, &timeout);
 212       if (found != -1)
 213         break;
 214       timeout.tv_sec += __NIS_PING_TIMEOUT_INCREMENT;
 215     }
 216
 217   return found;
 218 }