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- Committer: Bazaar Package Importer
- Author(s): Simon Kelley
- Date: 2005-05-04 13:25:23 UTC
- mfrom: (0.2.1 upstream) (1.1.2 hoary)
- Revision ID: james.westby@ubuntu.com-20050504132523-29x9nzdnkypp62nc
Tags: 2.22-2
Make the resolv.conf polling code resistant to
backwards-moving system clocks. (closes: #306117) (closes: #300694)
backwards-moving system clocks. (closes: #306117) (closes: #300694)
added
removed
src/isc.c
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/* dnsmasq is Copyright (c) 2000 - 2005 by Simon Kelley
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 dated June, 1991.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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*/
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/* Code in this file is based on contributions by John Volpe. */
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#include "dnsmasq.h"
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#ifdef HAVE_ISC_READER
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struct isc_lease {
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char *name, *fqdn;
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time_t expires;
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struct in_addr addr;
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struct isc_lease *next;
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};
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static struct isc_lease *leases = NULL;
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static off_t lease_file_size = (off_t)0;
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static ino_t lease_file_inode = (ino_t)0;
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static int logged_lease = 0;
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static int next_token (char *token, int buffsize, FILE * fp)
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{
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int c, count = 0;
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char *cp = token;
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while((c = getc(fp)) != EOF)
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{
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if (c == '#')
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do { c = getc(fp); } while (c != '\n' && c != EOF);
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if (c == ' ' || c == '\t' || c == '\n' || c == ';')
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{
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if (count)
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break;
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}
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else if ((c != '"') && (count<buffsize-1))
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{
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*cp++ = c;
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count++;
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}
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}
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*cp = 0;
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return count ? 1 : 0;
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}
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void load_dhcp(struct daemon *daemon, time_t now)
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{
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char *hostname = daemon->namebuff;
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char token[MAXTOK], *dot;
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struct in_addr host_address;
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time_t ttd, tts;
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FILE *fp;
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struct isc_lease *lease, *tmp, **up;
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struct stat statbuf;
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if (stat(daemon->lease_file, &statbuf) == -1)
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{
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if (!logged_lease)
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syslog(LOG_WARNING, "failed to access %s: %m", daemon->lease_file);
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logged_lease = 1;
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return;
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}
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logged_lease = 0;
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if ((statbuf.st_size <= lease_file_size) &&
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(statbuf.st_ino == lease_file_inode))
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return;
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lease_file_size = statbuf.st_size;
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lease_file_inode = statbuf.st_ino;
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if (!(fp = fopen (daemon->lease_file, "r")))
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{
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syslog (LOG_ERR, "failed to load %s: %m", daemon->lease_file);
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return;
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}
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syslog (LOG_INFO, "reading %s", daemon->lease_file);
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while ((next_token(token, MAXTOK, fp)))
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{
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if (strcmp(token, "lease") == 0)
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{
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hostname[0] = '\0';
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ttd = tts = (time_t)(-1);
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if (next_token(token, MAXTOK, fp) &&
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(host_address.s_addr = inet_addr(token)) != (in_addr_t) -1)
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{
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if (next_token(token, MAXTOK, fp) && *token == '{')
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{
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while (next_token(token, MAXTOK, fp) && *token != '}')
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{
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if ((strcmp(token, "client-hostname") == 0) ||
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(strcmp(token, "hostname") == 0))
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{
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if (next_token(hostname, MAXDNAME, fp))
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if (!canonicalise(hostname))
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{
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*hostname = 0;
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syslog(LOG_ERR, "bad name in %s", daemon->lease_file);
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}
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}
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else if ((strcmp(token, "ends") == 0) ||
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(strcmp(token, "starts") == 0))
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{
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struct tm lease_time;
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int is_ends = (strcmp(token, "ends") == 0);
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if (next_token(token, MAXTOK, fp) && /* skip weekday */
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next_token(token, MAXTOK, fp) && /* Get date from lease file */
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sscanf (token, "%d/%d/%d",
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&lease_time.tm_year,
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&lease_time.tm_mon,
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&lease_time.tm_mday) == 3 &&
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next_token(token, MAXTOK, fp) &&
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sscanf (token, "%d:%d:%d:",
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&lease_time.tm_hour,
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&lease_time.tm_min,
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&lease_time.tm_sec) == 3)
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{
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/* There doesn't seem to be a universally available library function
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which converts broken-down _GMT_ time to seconds-in-epoch.
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The following was borrowed from ISC dhcpd sources, where
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it is noted that it might not be entirely accurate for odd seconds.
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Since we're trying to get the same answer as dhcpd, that's just
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fine here. */
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static int months [11] = { 31, 59, 90, 120, 151, 181,
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212, 243, 273, 304, 334 };
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time_t time = ((((((365 * (lease_time.tm_year - 1970) + /* Days in years since '70 */
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(lease_time.tm_year - 1969) / 4 + /* Leap days since '70 */
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(lease_time.tm_mon > 1 /* Days in months this year */
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? months [lease_time.tm_mon - 2]
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: 0) +
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(lease_time.tm_mon > 2 && /* Leap day this year */
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!((lease_time.tm_year - 1972) & 3)) +
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lease_time.tm_mday - 1) * 24) + /* Day of month */
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lease_time.tm_hour) * 60) +
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lease_time.tm_min) * 60) + lease_time.tm_sec;
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if (is_ends)
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ttd = time;
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else
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tts = time; }
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}
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}
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/* missing info? */
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if (!*hostname)
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continue;
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if (ttd == (time_t)(-1))
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continue;
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/* We use 0 as infinite in ttd */
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if ((tts != -1) && (ttd == tts - 1))
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ttd = (time_t)0;
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else if (difftime(now, ttd) > 0)
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continue;
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if ((dot = strchr(hostname, '.')))
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{
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if (!daemon->domain_suffix || hostname_isequal(dot+1, daemon->domain_suffix))
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{
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syslog(LOG_WARNING,
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"Ignoring DHCP lease for %s because it has an illegal domain part",
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hostname);
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continue;
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}
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*dot = 0;
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}
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for (lease = leases; lease; lease = lease->next)
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if (hostname_isequal(lease->name, hostname))
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{
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lease->expires = ttd;
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lease->addr = host_address;
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break;
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}
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if (!lease && (lease = malloc(sizeof(struct isc_lease))))
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{
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lease->expires = ttd;
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lease->addr = host_address;
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lease->fqdn = NULL;
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lease->next = leases;
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if (!(lease->name = malloc(strlen(hostname)+1)))
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free(lease);
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else
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{
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leases = lease;
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strcpy(lease->name, hostname);
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if (daemon->domain_suffix &&
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(lease->fqdn = malloc(strlen(hostname) + strlen(daemon->domain_suffix) + 2)))
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{
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strcpy(lease->fqdn, hostname);
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strcat(lease->fqdn, ".");
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strcat(lease->fqdn, daemon->domain_suffix);
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}
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}
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}
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}
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}
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}
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}
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fclose(fp);
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/* prune expired leases */
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for (lease = leases, up = &leases; lease; lease = tmp)
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{
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tmp = lease->next;
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if (lease->expires != (time_t)0 && difftime(now, lease->expires) > 0)
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{
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*up = lease->next; /* unlink */
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free(lease->name);
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if (lease->fqdn)
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free(lease->fqdn);
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free(lease);
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}
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else
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up = &lease->next;
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}
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/* remove all existing DHCP cache entries */
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cache_unhash_dhcp();
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for (lease = leases; lease; lease = lease->next)
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{
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cache_add_dhcp_entry(daemon, lease->fqdn, &lease->addr, lease->expires);
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cache_add_dhcp_entry(daemon, lease->name, &lease->addr, lease->expires);
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}
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}
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#endif
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