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import of dnsmasq-2.0.tar.gz
This commit is contained in:
Simon Kelley
323
src/lease.c
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323
src/lease.c
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/* dnsmasq is Copyright (c) 2000-2003 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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FILE *lease_file;
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int dns_dirty, file_dirty;
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int lease_init(char *filename, char *domain, char *buff,
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char *buff2, time_t now, struct dhcp_config *dhcp_configs)
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{
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unsigned int e0, e1, e2, e3, e4, e5, 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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struct dhcp_config *config;
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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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if (!(lease_file = fopen(filename, "a+")))
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die("cannot open or create leases file: %s", NULL);
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rewind(lease_file); /* file opened with mode a+ which sets pointer at end. */
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while (fscanf(lease_file, "%lu %x:%x:%x:%x:%x:%x %d.%d.%d.%d %256s %500s",
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&ei, &e0, &e1, &e2, &e3, &e4, &e5, &a0, &a1, &a2, &a3, buff, buff2) == 13)
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{
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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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hwaddr[0] = e0;
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hwaddr[1] = e1;
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hwaddr[2] = e2;
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hwaddr[3] = e3;
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hwaddr[4] = e4;
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hwaddr[5] = e5;
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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(buff2, "*") == 0)
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clid_len = 0;
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else
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{
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int s = (strlen(buff2)/3) + 1;
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for (clid_len = 0; clid_len < s; clid_len++)
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{
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buff2[(clid_len*3)+2] = 0;
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buff2[clid_len] = strtol(&buff2[clid_len*3], NULL, 16);
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}
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}
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if (!(lease = lease_allocate(buff2, clid_len, addr)))
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die ("cannot get memory", NULL);
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lease->expires = expires;
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memcpy(lease->hwaddr, hwaddr, ETHER_ADDR_LEN);
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if (strcmp(buff, "*") != 0)
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lease_set_hostname(lease, buff, domain);
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}
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dns_dirty = 1;
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file_dirty = has_old;
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/* Deal with edits to the config file which may have changed the hostname
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associated with a hardware address. Do this after the main loop so that
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changes get written back out */
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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->hostname))
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lease_set_hostname(lease, config->hostname, domain);
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return fileno(lease_file);
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}
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void lease_update_dns(int force_dns)
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{
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struct dhcp_lease *lease;
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int i;
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if (file_dirty)
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{
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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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fprintf(lease_file, "%lu %.2x:%.2x:%.2x:%.2x:%.2x:%.2x %s %s ",
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(unsigned long)lease->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 ? lease->hostname : "*");
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if (lease->clid_len)
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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 = 0;
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}
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if (dns_dirty || force_dns)
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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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if (lease->fqdn)
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{
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cache_add_dhcp_entry(lease->fqdn, &lease->addr, lease->expires, F_REVERSE);
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cache_add_dhcp_entry(lease->hostname, &lease->addr, lease->expires, 0);
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}
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else if (lease->hostname)
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cache_add_dhcp_entry(lease->hostname, &lease->addr, lease->expires, F_REVERSE);
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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 = 1;
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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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}
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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 *clid, int clid_len)
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{
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/* zero length means clid from hwaddr: never match am option clid to
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a hardware-address derived clid */
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struct dhcp_lease *lease;
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if (clid_len)
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{
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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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}
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else
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{
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for (lease = leases; lease; lease = lease->next)
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if (!lease->clid &&
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memcmp(clid, lease->hwaddr, ETHER_ADDR_LEN) == 0)
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return lease;
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}
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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 *clid, int clid_len, struct in_addr addr)
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{
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struct dhcp_lease *lease;
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if (!(lease = malloc(sizeof(struct dhcp_lease))))
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return NULL;
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lease->clid = NULL;
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lease->clid_len = clid_len;
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if (clid_len)
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{
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if (!(lease->clid = malloc(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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memcpy(lease->clid, clid, clid_len);
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}
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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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lease->next = leases;
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leases = lease;
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file_dirty = 1;
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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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file_dirty = dns_dirty = 1;
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lease->expires = exp;
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}
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void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr)
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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 = 1;
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memcpy(lease->hwaddr, hwaddr, ETHER_ADDR_LEN);
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}
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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 && strcmp(lease->hostname, name) == 0)
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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)
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{
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new_name = malloc(strlen(name) + 1);
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strcpy(new_name, name);
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}
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if (suffix && !new_fqdn)
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{
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new_fqdn = malloc(strlen(name) + strlen(suffix) + 2);
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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 = dns_dirty = 1;
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}
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