aboutsummaryrefslogtreecommitdiff
path: root/nis/nis_findserv.c
blob: ebfca9961b494f66926358066b7d94441422d347 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <rpc/pmap_prot.h>
#include <rpc/pmap_clnt.h>
#include <rpcsvc/nis.h>

#include "nis_intern.h"

/* Private data kept per client handle, from sunrpc/clnt_udp.c */
struct cu_data
  {
    int cu_sock;
    bool_t cu_closeit;
    struct sockaddr_in cu_raddr;
    int cu_rlen;
    struct timeval cu_wait;
    struct timeval cu_total;
    struct rpc_err cu_error;
    XDR cu_outxdrs;
    u_int cu_xdrpos;
    u_int cu_sendsz;
    char *cu_outbuf;
    u_int cu_recvsz;
    char cu_inbuf[1];
  };


/*
 * Find the mapped port for program,version.
 * Calls the pmap service remotely to do the lookup.
 * Returns 0 if no map exists.
 */
u_short
__pmap_getnisport (struct sockaddr_in *address, u_long program,
		   u_long version, u_int protocol)
{
  return __libc_rpc_getport (address, program, version, protocol, 1, 1);
}

/* This is now the public function, which should find the fastest server */

struct findserv_req
{
  struct sockaddr_in sin;
  u_int32_t xid;
  u_int server_nr;
  u_int server_ep;
};


static long int
__nis_findfastest_with_timeout (dir_binding *bind,
				const struct timeval *timeout)
{
  static const struct timeval TIMEOUT00 = { 0, 0 };
  struct findserv_req *pings;
  struct sockaddr_in sin, saved_sin;
  int found = -1;
  u_int32_t xid_seed;
  int sock, dontblock = 1;
  CLIENT *clnt;
  u_long i, j, pings_count, pings_max, fastest = -1;
  struct cu_data *cu;

  pings_max = bind->server_len * 2;	/* Reserve a little bit more memory
					   for multihomed hosts */
  pings_count = 0;
  pings = malloc (sizeof (struct findserv_req) * pings_max);
  xid_seed = (u_int32_t) (time (NULL) ^ getpid ());

  if (__glibc_unlikely (pings == NULL))
    return -1;

  memset (&sin, '\0', sizeof (sin));
  sin.sin_family = AF_INET;
  for (i = 0; i < bind->server_len; i++)
    for (j = 0; j < bind->server_val[i].ep.ep_len; ++j)
      if (strcmp (bind->server_val[i].ep.ep_val[j].family, "inet") == 0)
	if ((bind->server_val[i].ep.ep_val[j].proto == NULL) ||
	    (bind->server_val[i].ep.ep_val[j].proto[0] == '-') ||
	    (bind->server_val[i].ep.ep_val[j].proto[0] == '\0'))
	  {
	    sin.sin_addr.s_addr =
	      inetstr2int (bind->server_val[i].ep.ep_val[j].uaddr);
	    if (sin.sin_addr.s_addr == 0)
	      continue;
	    sin.sin_port = htons (__pmap_getnisport (&sin, NIS_PROG,
						     NIS_VERSION,
						     IPPROTO_UDP));
	    if (sin.sin_port == 0)
	      continue;

	    if (pings_count >= pings_max)
	      {
		struct findserv_req *new_pings;

		pings_max += 10;
		new_pings = realloc (pings, sizeof (struct findserv_req) *
				     pings_max);
		if (__glibc_unlikely (new_pings == NULL))
		  {
		    free (pings);
		    return -1;
		  }
		pings = new_pings;
	      }
	    memcpy ((char *) &pings[pings_count].sin, (char *) &sin,
		    sizeof (sin));
	    memcpy ((char *)&saved_sin, (char *)&sin, sizeof(sin));
	    pings[pings_count].xid = xid_seed + pings_count;
	    pings[pings_count].server_nr = i;
	    pings[pings_count].server_ep = j;
	    ++pings_count;
	  }

  /* Make sure at least one server was assigned */
  if (pings_count == 0)
    {
      free (pings);
      return -1;
    }

  /* Create RPC handle */
  sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  clnt = clntudp_create (&saved_sin, NIS_PROG, NIS_VERSION, *timeout, &sock);
  if (clnt == NULL)
    {
      close (sock);
      free (pings);
      return -1;
    }
  auth_destroy (clnt->cl_auth);
  clnt->cl_auth = authunix_create_default ();
  cu = (struct cu_data *) clnt->cl_private;
  ioctl (sock, FIONBIO, &dontblock);
  /* Send to all servers the NULLPROC */
  for (i = 0; i < pings_count; ++i)
    {
      /* clntudp_call() will increment, subtract one */
      *((u_int32_t *) (cu->cu_outbuf)) = pings[i].xid - 1;
      memcpy ((char *) &cu->cu_raddr, (char *) &pings[i].sin,
	      sizeof (struct sockaddr_in));
      /* Transmit to NULLPROC, return immediately. */
      clnt_call (clnt, NULLPROC,
		 (xdrproc_t) xdr_void, (caddr_t) 0,
		 (xdrproc_t) xdr_void, (caddr_t) 0, TIMEOUT00);
    }

  while (found == -1) {
    /* Receive reply from NULLPROC asynchronously. Note null inproc. */
    int rc = clnt_call (clnt, NULLPROC,
			(xdrproc_t) NULL, (caddr_t) 0,
			(xdrproc_t) xdr_void, (caddr_t) 0,
			*timeout);
    if (RPC_SUCCESS == rc) {
      u_int32_t val;
      memcpy (&val, cu->cu_inbuf, sizeof (u_int32_t));
      fastest = val - xid_seed;
      if (fastest < pings_count) {
	bind->server_used = pings[fastest].server_nr;
	bind->current_ep = pings[fastest].server_ep;
	found = 1;
      }
    } else {
      /*      clnt_perror(clnt, "__nis_findfastest"); */
      break;
    }
  }


  auth_destroy (clnt->cl_auth);
  clnt_destroy (clnt);
  close (sock);

  free (pings);

  return found;
}


long int
__nis_findfastest (dir_binding *bind)
{
  struct timeval timeout = { __NIS_PING_TIMEOUT_START, 0 };
  long int found = -1;
  long int retry = __NIS_PING_RETRY + 1;

  while (retry--)
    {
      found = __nis_findfastest_with_timeout (bind, &timeout);
      if (found != -1)
	break;
      timeout.tv_sec += __NIS_PING_TIMEOUT_INCREMENT;
    }

  return found;
}