--- /dev/null
+/* dnsmasq is Copyright (c) 2014 John Volpe, Simon Kelley and
+ Michael Tremer
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 dated June, 1991, or
+ (at your option) version 3 dated 29 June, 2007.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+ Code in this file is based on contributions by John Volpe and
+ Simon Kelley. Updated for recent versions of dnsmasq by
+ Michael Tremer.
+*/
+
+#include "dnsmasq.h"
+
+#ifdef HAVE_ISC_READER
+#define MAXTOK 50
+
+struct isc_dhcp_lease {
+ char* name;
+ char* fqdn;
+ time_t expires;
+ struct in_addr addr;
+ struct isc_dhcp_lease* next;
+};
+
+static struct isc_dhcp_lease* dhcp_lease_new() {
+ struct isc_dhcp_lease* lease = whine_malloc(sizeof(*lease));
+
+ lease->name = NULL;
+ lease->fqdn = NULL;
+ lease->next = NULL;
+
+ return lease;
+}
+
+static void dhcp_lease_free(struct isc_dhcp_lease* lease) {
+ if (!lease)
+ return;
+
+ if (lease->name)
+ free(lease->name);
+ if (lease->fqdn)
+ free(lease->fqdn);
+ free(lease);
+}
+
+static int next_token(char* token, int buffsize, FILE* fp) {
+ int c, count = 0;
+ char* cp = token;
+
+ while ((c = getc(fp)) != EOF) {
+ if (c == '#') {
+ do {
+ c = getc(fp);
+ } while (c != '\n' && c != EOF);
+ }
+
+ if (c == ' ' || c == '\t' || c == '\n' || c == ';') {
+ if (count)
+ break;
+ } else if ((c != '"') && (count < buffsize - 1)) {
+ *cp++ = c;
+ count++;
+ }
+ }
+
+ *cp = 0;
+ return count ? 1 : 0;
+}
+
+static time_t parse_lease_time(const char* token_date, const char* token_time) {
+ time_t time = (time_t)(-1);
+ struct tm lease_time;
+
+ static const int months[11] = {31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
+
+ if (sscanf(token_date, "%d/%d/%d", &lease_time.tm_year, &lease_time.tm_mon, &lease_time.tm_mday) == 3) {
+ if (sscanf(token_time, "%d:%d:%d", &lease_time.tm_hour, &lease_time.tm_min, &lease_time.tm_sec) == 3) {
+ /* There doesn't seem to be a universally available library function
+ which converts broken-down _GMT_ time to seconds-in-epoch.
+ The following was borrowed from ISC dhcpd sources, where
+ it is noted that it might not be entirely accurate for odd seconds.
+ Since we're trying to get the same answer as dhcpd, that's just
+ fine here. */
+ time = ((((((365 * (lease_time.tm_year - 1970) +
+ (lease_time.tm_year - 1969) / 4 +
+ (lease_time.tm_mon > 1 ? months[lease_time.tm_mon - 2] : 0) +
+ (lease_time.tm_mon > 2 && !((lease_time.tm_year - 1972) & 3 )) +
+ (lease_time.tm_mday - 1)) * 24) +
+ lease_time.tm_hour) * 60) +
+ lease_time.tm_mon) * 60) +
+ lease_time.tm_sec;
+ }
+ }
+
+ return time;
+}
+
+static off_t lease_file_size = (off_t)0;
+static ino_t lease_file_inode = (ino_t)0;
+
+void load_dhcp(time_t now) {
+ struct isc_dhcp_lease* leases = NULL;
+
+ struct stat statbuf;
+ if (stat(daemon->lease_file, &statbuf) == -1) {
+ return;
+ }
+
+ /* Do nothing if the lease file has not changed. */
+ if ((statbuf.st_size <= lease_file_size) && (statbuf.st_ino == lease_file_inode))
+ return;
+
+ lease_file_size = statbuf.st_size;
+ lease_file_inode = statbuf.st_ino;
+
+ FILE* fp = fopen(daemon->lease_file, "r");
+ if (!fp) {
+ my_syslog(LOG_ERR, _("failed to load %s:%s"), daemon->lease_file, strerror(errno));
+ return;
+ }
+
+ my_syslog(LOG_INFO, _("reading %s"), daemon->lease_file);
+
+ char* hostname = daemon->namebuff;
+ struct in_addr host_address;
+ time_t time_starts = -1;
+ time_t time_ends = -1;
+ int nomem;
+
+ char token[MAXTOK];
+ while ((next_token(token, MAXTOK, fp))) {
+ if (strcmp(token, "lease") == 0) {
+ hostname[0] = '\0';
+
+ if (next_token(token, MAXTOK, fp) && ((host_address.s_addr = inet_addr(token)) != (in_addr_t)-1)) {
+ if (next_token(token, MAXTOK, fp) && *token == '{') {
+ while (next_token(token, MAXTOK, fp) && *token != '}') {
+ if ((strcmp(token, "client-hostname") == 0) || (strcmp(token, "hostname") == 0)) {
+ if (next_token(hostname, MAXDNAME, fp)) {
+ if (!canonicalise(hostname, &nomem)) {
+ *hostname = 0;
+ my_syslog(LOG_ERR, _("bad name in %s"), daemon->lease_file);
+ }
+ }
+ } else if ((strcmp(token, "starts") == 0) || (strcmp(token, "ends") == 0)) {
+ char token_date[MAXTOK];
+ char token_time[MAXTOK];
+
+ int is_starts = strcmp(token, "starts") == 0;
+
+ // Throw away the weekday and parse the date.
+ if (next_token(token, MAXTOK, fp) && next_token(token_date, MAXTOK, fp) && next_token(token_time, MAXTOK, fp)) {
+ time_t time = parse_lease_time(token_date, token_time);
+
+ if (is_starts)
+ time_starts = time;
+ else
+ time_ends = time;
+ }
+ }
+ }
+
+ if (!*hostname)
+ continue;
+
+ if ((time_starts == -1) || (time_ends == -1))
+ continue;
+
+ if (difftime(now, time_ends) > 0)
+ continue;
+
+ char* dot = strchr(hostname, '.');
+ if (dot) {
+ if (!daemon->domain_suffix || hostname_isequal(dot + 1, daemon->domain_suffix)) {
+ my_syslog(LOG_WARNING,
+ _("Ignoring DHCP lease for %s because it has an illegal domain part"),
+ hostname);
+ continue;
+ }
+ *dot = 0;
+ }
+
+ struct isc_dhcp_lease* lease = dhcp_lease_new();
+ lease->name = strdup(hostname);
+ lease->addr = host_address;
+ lease->expires = time_ends;
+ lease->next = NULL;
+
+ if (daemon->domain_suffix) {
+ asprintf(&lease->fqdn, "%s.%s", hostname, daemon->domain_suffix);
+ }
+
+ if (!leases)
+ leases = lease;
+ else
+ leases->next = lease;
+ }
+ }
+ }
+ }
+
+ fclose(fp);
+
+ // Drop all entries.
+ cache_unhash_dhcp();
+
+ while (leases) {
+ struct isc_dhcp_lease *lease = leases;
+ leases = lease->next;
+
+ if (lease->fqdn) {
+ cache_add_dhcp_entry(lease->fqdn, AF_INET, (struct all_addr*)&lease->addr.s_addr, lease->expires);
+ }
+
+ if (lease->name) {
+ cache_add_dhcp_entry(lease->name, AF_INET, (struct all_addr*)&lease->addr.s_addr, lease->expires);
+ }
+
+ // Cleanup
+ dhcp_lease_free(lease);
+ }
+}
+
+#endif
projects / people / ms / dnsmasq.git / commitdiff
