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1 | /* Copyright (C) 1997-2024 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 | } |