1 /* $OpenBSD: db.c,v 1.18 2017/02/13 23:04:05 krw Exp $ */
2
3 /*
4 * Persistent database management routines for DHCPD.
5 */
6
7 /*
8 * Copyright (c) 1995, 1996 The Internet Software Consortium.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 *
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of The Internet Software Consortium nor the names
21 * of its contributors may be used to endorse or promote products derived
22 * from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
25 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
26 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
28 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
29 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
32 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
33 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * This software has been written for the Internet Software Consortium
39 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
40 * Enterprises. To learn more about the Internet Software Consortium,
41 * see ``http://www.vix.com/isc''. To learn more about Vixie
42 * Enterprises, see ``http://www.vix.com''.
43 */
44
45 #include <sys/types.h>
46 #include <sys/socket.h>
47
48 #include <net/if.h>
49
50 #include <netinet/in.h>
51
52 #include <fcntl.h>
53 #include <stdio.h>
54 #include <time.h>
55 #include <unistd.h>
56
57 #include "dhcp.h"
58 #include "tree.h"
59 #include "dhcpd.h"
60 #include "log.h"
61
62 FILE *db_file;
63
64 static int counting = 0;
65 static int count = 0;
66 time_t write_time;
67
68 /*
69 * Write the specified lease to the current lease database file.
70 */
71 int
write_lease(struct lease * lease)72 write_lease(struct lease *lease)
73 {
74 char tbuf[26]; /* "w yyyy/mm/dd hh:mm:ss UTC" */
75 size_t rsltsz;
76 int errors = 0;
77 int i;
78
79 if (counting)
80 ++count;
81 if (fprintf(db_file, "lease %s {\n", piaddr(lease->ip_addr)) == -1)
82 ++errors;
83
84 rsltsz = strftime(tbuf, sizeof(tbuf), DB_TIMEFMT,
85 gmtime(&lease->starts));
86 if (rsltsz == 0 || fprintf(db_file, "\tstarts %s;\n", tbuf) == -1)
87 errors++;
88
89 rsltsz = strftime(tbuf, sizeof(tbuf), DB_TIMEFMT,
90 gmtime(&lease->ends));
91 if (rsltsz == 0 || fprintf(db_file, "\tends %s;\n", tbuf) == -1)
92 errors++;
93
94 if (lease->hardware_addr.hlen) {
95 if (fprintf(db_file, "\thardware %s %s;",
96 hardware_types[lease->hardware_addr.htype],
97 print_hw_addr(lease->hardware_addr.htype,
98 lease->hardware_addr.hlen,
99 lease->hardware_addr.haddr)) == -1)
100 ++errors;
101 }
102
103 if (lease->uid_len) {
104 int j;
105
106 if (fprintf(db_file, "\n\tuid %2.2x", lease->uid[0]) == -1)
107 ++errors;
108
109 for (j = 1; j < lease->uid_len; j++) {
110 if (fprintf(db_file, ":%2.2x", lease->uid[j]) == -1)
111 ++errors;
112 }
113 if (fputc(';', db_file) == EOF)
114 ++errors;
115 }
116
117 if (lease->flags & BOOTP_LEASE) {
118 if (fprintf(db_file, "\n\tdynamic-bootp;") == -1)
119 ++errors;
120 }
121
122 if (lease->flags & ABANDONED_LEASE) {
123 if (fprintf(db_file, "\n\tabandoned;") == -1)
124 ++errors;
125 }
126
127 if (lease->client_hostname) {
128 for (i = 0; lease->client_hostname[i]; i++)
129 if (lease->client_hostname[i] < 33 ||
130 lease->client_hostname[i] > 126)
131 goto bad_client_hostname;
132 if (fprintf(db_file, "\n\tclient-hostname \"%s\";",
133 lease->client_hostname) == -1)
134 ++errors;
135 }
136
137 bad_client_hostname:
138 if (lease->hostname) {
139 for (i = 0; lease->hostname[i]; i++)
140 if (lease->hostname[i] < 33 ||
141 lease->hostname[i] > 126)
142 goto bad_hostname;
143 if (fprintf(db_file, "\n\thostname \"%s\";",
144 lease->hostname) == -1)
145 ++errors;
146 }
147
148 bad_hostname:
149 if (fputs("\n}\n", db_file) == EOF)
150 ++errors;
151
152 if (errors)
153 log_info("write_lease: unable to write lease %s",
154 piaddr(lease->ip_addr));
155
156 return (!errors);
157 }
158
159 /*
160 * Commit any leases that have been written out...
161 */
162 int
commit_leases(void)163 commit_leases(void)
164 {
165 /*
166 * Commit any outstanding writes to the lease database file. We need to
167 * do this even if we're rewriting the file below, just in case the
168 * rewrite fails.
169 */
170 if (fflush(db_file) == EOF) {
171 log_warn("commit_leases: unable to commit");
172 return (0);
173 }
174
175 if (fsync(fileno(db_file)) == -1) {
176 log_warn("commit_leases: unable to commit");
177 return (0);
178 }
179
180 /*
181 * If we've written more than a thousand leases or if we haven't
182 * rewritten the lease database in over an hour, rewrite it now.
183 */
184 if (count > 1000 || (count && cur_time - write_time > 3600)) {
185 count = 0;
186 write_time = cur_time;
187 new_lease_file();
188 }
189
190 return (1);
191 }
192
193 void
db_startup(void)194 db_startup(void)
195 {
196 int db_fd;
197
198 /* open lease file. once we dropped privs it has to stay open */
199 db_fd = open(path_dhcpd_db, O_WRONLY|O_CREAT, 0640);
200 if (db_fd == -1)
201 fatal("Can't create new lease file");
202 if ((db_file = fdopen(db_fd, "w")) == NULL)
203 fatalx("Can't fdopen new lease file!");
204
205 /* Read in the existing lease file... */
206 read_leases();
207 time(&write_time);
208
209 new_lease_file();
210 }
211
212 void
new_lease_file(void)213 new_lease_file(void)
214 {
215 fflush(db_file);
216 rewind(db_file);
217
218 /* Write out all the leases that we know of... */
219 counting = 0;
220 write_leases();
221
222 fflush(db_file);
223 ftruncate(fileno(db_file), ftello(db_file));
224 fsync(fileno(db_file));
225
226 counting = 1;
227 }
228