1 /* Copyright (C) 1997-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <string.h>
19 #include <time.h>
20 #include <unistd.h>
21 #include <sys/ioctl.h>
22 #include <sys/socket.h>
23 #include <rpc/pmap_prot.h>
24 #include <rpc/pmap_clnt.h>
25 #include <rpcsvc/nis.h>
26
27 #include "nis_intern.h"
28
29 /* Private data kept per client handle, from sunrpc/clnt_udp.c */
30 struct cu_data
31 {
32 int cu_sock;
33 bool_t cu_closeit;
34 struct sockaddr_in cu_raddr;
35 int cu_rlen;
36 struct timeval cu_wait;
37 struct timeval cu_total;
38 struct rpc_err cu_error;
39 XDR cu_outxdrs;
40 u_int cu_xdrpos;
41 u_int cu_sendsz;
42 char *cu_outbuf;
43 u_int cu_recvsz;
44 char cu_inbuf[1];
45 };
46
47
48 /*
49 * Find the mapped port for program,version.
50 * Calls the pmap service remotely to do the lookup.
51 * Returns 0 if no map exists.
52 */
53 u_short
54 __pmap_getnisport (struct sockaddr_in *address, u_long program,
55 u_long version, u_int protocol)
56 {
57 return __libc_rpc_getport (address, program, version, protocol, 1, 1);
58 }
59
60 /* This is now the public function, which should find the fastest server */
61
62 struct findserv_req
63 {
64 struct sockaddr_in sin;
65 uint32_t xid;
66 u_int server_nr;
67 u_int server_ep;
68 };
69
70
71 static long int
72 __nis_findfastest_with_timeout (dir_binding *bind,
73 const struct timeval *timeout)
74 {
75 static const struct timeval TIMEOUT00 = { 0, 0 };
76 struct findserv_req *pings;
77 struct sockaddr_in sin, saved_sin;
78 int found = -1;
79 uint32_t xid_seed;
80 int sock, dontblock = 1;
81 CLIENT *clnt;
82 u_long i, j, pings_count, pings_max, fastest = -1;
83 struct cu_data *cu;
84
85 pings_max = bind->server_len * 2; /* Reserve a little bit more memory
86 for multihomed hosts */
87 pings_count = 0;
88 pings = malloc (sizeof (struct findserv_req) * pings_max);
89 xid_seed = (uint32_t) (time (NULL) ^ getpid ());
90
91 if (__glibc_unlikely (pings == NULL))
92 return -1;
93
94 memset (&sin, '\0', sizeof (sin));
95 sin.sin_family = AF_INET;
96 for (i = 0; i < bind->server_len; i++)
97 for (j = 0; j < bind->server_val[i].ep.ep_len; ++j)
98 if (strcmp (bind->server_val[i].ep.ep_val[j].family, "inet") == 0)
99 if ((bind->server_val[i].ep.ep_val[j].proto == NULL)
100 || (bind->server_val[i].ep.ep_val[j].proto[0] == '-')
101 || (bind->server_val[i].ep.ep_val[j].proto[0] == '\0'))
102 {
103 sin.sin_addr.s_addr =
104 inetstr2int (bind->server_val[i].ep.ep_val[j].uaddr);
105 if (sin.sin_addr.s_addr == 0)
106 continue;
107 sin.sin_port = htons (__pmap_getnisport (&sin, NIS_PROG,
108 NIS_VERSION,
109 IPPROTO_UDP));
110 if (sin.sin_port == 0)
111 continue;
112
113 if (pings_count >= pings_max)
114 {
115 struct findserv_req *new_pings;
116
117 pings_max += 10;
118 new_pings = realloc (pings, sizeof (struct findserv_req) *
119 pings_max);
120 if (__glibc_unlikely (new_pings == NULL))
121 {
122 free (pings);
123 return -1;
124 }
125 pings = new_pings;
126 }
127 memcpy ((char *) &pings[pings_count].sin, (char *) &sin,
128 sizeof (sin));
129 memcpy ((char *)&saved_sin, (char *)&sin, sizeof (sin));
130 pings[pings_count].xid = xid_seed + pings_count;
131 pings[pings_count].server_nr = i;
132 pings[pings_count].server_ep = j;
133 ++pings_count;
134 }
135
136 /* Make sure at least one server was assigned */
137 if (pings_count == 0)
138 {
139 free (pings);
140 return -1;
141 }
142
143 /* Create RPC handle */
144 sock = socket (AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
145 clnt = clntudp_create (&saved_sin, NIS_PROG, NIS_VERSION, *timeout, &sock);
146 if (clnt == NULL)
147 {
148 close (sock);
149 free (pings);
150 return -1;
151 }
152 auth_destroy (clnt->cl_auth);
153 clnt->cl_auth = authunix_create_default ();
154 cu = (struct cu_data *) clnt->cl_private;
155 ioctl (sock, FIONBIO, &dontblock);
156 /* Send to all servers the NULLPROC */
157 for (i = 0; i < pings_count; ++i)
158 {
159 /* clntudp_call() will increment, subtract one */
160 *((uint32_t *) (cu->cu_outbuf)) = pings[i].xid - 1;
161 memcpy ((char *) &cu->cu_raddr, (char *) &pings[i].sin,
162 sizeof (struct sockaddr_in));
163 /* Transmit to NULLPROC, return immediately. */
164 clnt_call (clnt, NULLPROC,
165 (xdrproc_t) xdr_void, (caddr_t) 0,
166 (xdrproc_t) xdr_void, (caddr_t) 0, TIMEOUT00);
167 }
168
169 while (found == -1) {
170 /* Receive reply from NULLPROC asynchronously. Note null inproc. */
171 int rc = clnt_call (clnt, NULLPROC,
172 (xdrproc_t) NULL, (caddr_t) 0,
173 (xdrproc_t) xdr_void, (caddr_t) 0,
174 *timeout);
175 if (RPC_SUCCESS == rc) {
176 uint32_t val;
177 memcpy (&val, cu->cu_inbuf, sizeof (uint32_t));
178 fastest = val - 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 }