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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/lease.c
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/* dnsmasq is Copyright (c) 2000-2005 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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/* Author's email: simon@thekelleys.org.uk */
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#include "dnsmasq.h"
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static struct dhcp_lease *leases;
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static FILE *lease_file;
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static int dns_dirty;
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enum { no, yes, force } file_dirty;
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static int leases_left;
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void lease_init(struct daemon *daemon, time_t now)
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{
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unsigned int a0, a1, a2, a3;
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unsigned long ei;
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time_t expires;
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unsigned char hwaddr[ETHER_ADDR_LEN];
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struct in_addr addr;
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struct dhcp_lease *lease;
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int clid_len = 0;
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int has_old = 0;
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leases = NULL;
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leases_left = daemon->dhcp_max;
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/* NOTE: need a+ mode to create file if it doesn't exist */
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if (!(lease_file = fopen(daemon->lease_file, "a+")))
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die("cannot open or create leases file: %s", NULL);
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/* a+ mode lease pointer at end. */
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rewind(lease_file);
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/* client-id max length is 255 which is 255*2 digits + 254 colons
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borrow DNS packet buffer which is always larger than 1000 bytes */
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while (fscanf(lease_file, "%lu %40s %d.%d.%d.%d %255s %764s",
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&ei, daemon->dhcp_buff2, &a0, &a1, &a2, &a3,
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daemon->dhcp_buff, daemon->packet) == 8)
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{
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#ifdef HAVE_BROKEN_RTC
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if (ei)
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expires = (time_t)ei + now;
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else
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expires = (time_t)0;
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#else
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/* strictly time_t is opaque, but this hack should work on all sane systems,
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even when sizeof(time_t) == 8 */
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expires = (time_t)ei;
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if (ei != 0 && difftime(now, expires) > 0)
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{
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has_old = 1;
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continue; /* expired */
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}
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#endif
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parse_hex(daemon->dhcp_buff2, hwaddr, ETHER_ADDR_LEN, NULL);
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addr.s_addr = htonl((a0<<24) + (a1<<16) + (a2<<8) + a3);
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/* decode hex in place */
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if (strcmp(daemon->packet, "*") == 0)
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clid_len = 0;
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else
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clid_len = parse_hex(daemon->packet, daemon->packet, 255, NULL);
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if (!(lease = lease_allocate(hwaddr, daemon->packet, clid_len, addr)))
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die ("too many stored leases", NULL);
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lease->expires = expires;
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if (strcmp(daemon->dhcp_buff, "*") != 0)
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lease_set_hostname(lease, daemon->dhcp_buff, daemon->domain_suffix);
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}
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dns_dirty = 1;
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file_dirty = has_old ? yes: no;
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daemon->lease_fd = fileno(lease_file);
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}
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void lease_update_from_configs(struct dhcp_config *dhcp_configs, char *domain)
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{
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/* changes to the config may change current leases. */
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struct dhcp_lease *lease;
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struct dhcp_config *config;
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for (lease = leases; lease; lease = lease->next)
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if ((config = find_config(dhcp_configs, NULL, lease->clid, lease->clid_len, lease->hwaddr, NULL)) &&
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(config->flags & CONFIG_NAME))
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lease_set_hostname(lease, config->hostname, domain);
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}
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void lease_update_file(int always, time_t now)
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{
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struct dhcp_lease *lease;
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int i = always; /* avoid warning */
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unsigned long expires;
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#ifdef HAVE_BROKEN_RTC
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if (always || file_dirty == force)
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{
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lease_prune(NULL, now);
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#else
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if (file_dirty != no)
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{
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#endif
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rewind(lease_file);
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ftruncate(fileno(lease_file), 0);
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for (lease = leases; lease; lease = lease->next)
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{
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#ifdef HAVE_BROKEN_RTC
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if (lease->expires)
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expires = (unsigned long) difftime(lease->expires, now);
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else
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expires = 0;
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#else
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expires = now; /* eliminate warning */
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expires = (unsigned long)lease->expires;
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#endif
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fprintf(lease_file, "%lu %.2x:%.2x:%.2x:%.2x:%.2x:%.2x %s %s ",
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expires, lease->hwaddr[0], lease->hwaddr[1],
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lease->hwaddr[2], lease->hwaddr[3], lease->hwaddr[4],
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lease->hwaddr[5], inet_ntoa(lease->addr),
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lease->hostname && strlen(lease->hostname) != 0 ? lease->hostname : "*");
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if (lease->clid && lease->clid_len != 0)
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{
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for (i = 0; i < lease->clid_len - 1; i++)
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fprintf(lease_file, "%.2x:", lease->clid[i]);
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fprintf(lease_file, "%.2x\n", lease->clid[i]);
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}
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else
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fprintf(lease_file, "*\n");
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}
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fflush(lease_file);
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fsync(fileno(lease_file));
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file_dirty = no;
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}
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}
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void lease_update_dns(struct daemon *daemon)
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{
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struct dhcp_lease *lease;
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if (dns_dirty)
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{
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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->hostname, &lease->addr, lease->expires);
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}
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dns_dirty = 0;
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}
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}
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void lease_prune(struct dhcp_lease *target, time_t now)
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{
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struct dhcp_lease *lease, *tmp, **up;
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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 != 0 && difftime(now, lease->expires) > 0) || lease == target)
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{
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file_dirty = yes;
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*up = lease->next; /* unlink */
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if (lease->hostname)
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{
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free(lease->hostname);
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dns_dirty = 1;
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}
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if (lease->fqdn)
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free(lease->fqdn);
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if (lease->clid)
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free(lease->clid);
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free(lease);
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leases_left++;
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}
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else
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up = &lease->next;
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}
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}
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struct dhcp_lease *lease_find_by_client(unsigned char *hwaddr,
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unsigned char *clid, int clid_len)
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{
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struct dhcp_lease *lease;
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if (clid)
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for (lease = leases; lease; lease = lease->next)
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if (lease->clid && clid_len == lease->clid_len &&
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memcmp(clid, lease->clid, clid_len) == 0)
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return lease;
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for (lease = leases; lease; lease = lease->next)
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if ((!lease->clid || !clid) &&
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memcmp(hwaddr, lease->hwaddr, ETHER_ADDR_LEN) == 0)
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return lease;
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return NULL;
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}
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struct dhcp_lease *lease_find_by_addr(struct in_addr addr)
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{
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struct dhcp_lease *lease;
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for (lease = leases; lease; lease = lease->next)
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if (lease->addr.s_addr == addr.s_addr)
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return lease;
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return NULL;
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}
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struct dhcp_lease *lease_allocate(unsigned char *hwaddr, unsigned char *clid,
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int clid_len, struct in_addr addr)
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{
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struct dhcp_lease *lease;
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if (!leases_left || !(lease = malloc(sizeof(struct dhcp_lease))))
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return NULL;
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lease->clid = NULL;
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lease->hostname = lease->fqdn = NULL;
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lease->addr = addr;
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memset(lease->hwaddr, 0, ETHER_ADDR_LEN);
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lease->expires = 1;
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if (!lease_set_hwaddr(lease, hwaddr, clid, clid_len))
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{
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free(lease);
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return NULL;
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}
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lease->next = leases;
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leases = lease;
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file_dirty = force;
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leases_left--;
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return lease;
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}
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void lease_set_expires(struct dhcp_lease *lease, time_t exp)
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{
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if (exp != lease->expires)
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{
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file_dirty = yes;
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dns_dirty = 1;
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}
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lease->expires = exp;
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}
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int lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr,
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unsigned char *clid, int clid_len)
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{
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if (memcmp(lease->hwaddr, hwaddr, ETHER_ADDR_LEN) != 0)
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{
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file_dirty = force;
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memcpy(lease->hwaddr, hwaddr, ETHER_ADDR_LEN);
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}
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/* only update clid when one is available, stops packets
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without a clid removing the record. Lease init uses
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clid_len == 0 for no clid. */
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if (clid_len != 0 && clid)
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{
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if (!lease->clid)
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lease->clid_len = 0;
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if (lease->clid_len != clid_len)
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{
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file_dirty = force;
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if (lease->clid)
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free(lease->clid);
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if (!(lease->clid = malloc(clid_len)))
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return 0;
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}
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else if (memcmp(lease->clid, clid, clid_len) != 0)
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file_dirty = force;
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lease->clid_len = clid_len;
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memcpy(lease->clid, clid, clid_len);
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}
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return 1;
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}
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void lease_set_hostname(struct dhcp_lease *lease, char *name, char *suffix)
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{
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struct dhcp_lease *lease_tmp;
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char *new_name = NULL, *new_fqdn = NULL;
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if (lease->hostname && name && hostname_isequal(lease->hostname, name))
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return;
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if (!name && !lease->hostname)
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return;
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/* If a machine turns up on a new net without dropping the old lease,
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or two machines claim the same name, then we end up with two interfaces with
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the same name. Check for that here and remove the name from the old lease. */
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if (name)
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{
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for (lease_tmp = leases; lease_tmp; lease_tmp = lease_tmp->next)
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if (lease_tmp->hostname && hostname_isequal(lease_tmp->hostname, name))
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{
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new_name = lease_tmp->hostname;
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lease_tmp->hostname = NULL;
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if (lease_tmp->fqdn)
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{
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new_fqdn = lease_tmp->fqdn;
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lease_tmp->fqdn = NULL;
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}
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}
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if (!new_name && (new_name = malloc(strlen(name) + 1)))
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strcpy(new_name, name);
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if (suffix && !new_fqdn && (new_fqdn = malloc(strlen(name) + strlen(suffix) + 2)))
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{
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strcpy(new_fqdn, name);
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strcat(new_fqdn, ".");
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strcat(new_fqdn, suffix);
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}
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}
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if (lease->hostname)
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free(lease->hostname);
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if (lease->fqdn)
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free(lease->fqdn);
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lease->hostname = new_name;
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lease->fqdn = new_fqdn;
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file_dirty = force;
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dns_dirty = 1;
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}
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