Accumulated 2.60 changes going into git

[people/ms/dnsmasq.git] / src / lease.c

/* dnsmasq is Copyright (c) 2000-2011 Simon Kelley

   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/>.
*/

#include "dnsmasq.h"

#ifdef HAVE_DHCP

static struct dhcp_lease *leases = NULL, *old_leases = NULL;
static int dns_dirty, file_dirty, leases_left;

void lease_init(time_t now)
{
  unsigned long ei;
  struct all_addr addr;
  struct dhcp_lease *lease;
  int clid_len, hw_len, hw_type;
  FILE *leasestream;
#ifdef HAVE_DHCP6
  int v6pass = 0;
#endif
  
  /* These each hold a DHCP option max size 255
     and get a terminating zero added */
  daemon->dhcp_buff = safe_malloc(256);
  daemon->dhcp_buff2 = safe_malloc(256); 
  daemon->dhcp_buff3 = safe_malloc(256);
 
  leases_left = daemon->dhcp_max;

  if (option_bool(OPT_LEASE_RO))
    {
      /* run "<lease_change_script> init" once to get the
	 initial state of the database. If leasefile-ro is
	 set without a script, we just do without any 
	 lease database. */
#ifdef HAVE_SCRIPT
      if (daemon->lease_change_command)
	{
	  strcpy(daemon->dhcp_buff, daemon->lease_change_command);
	  strcat(daemon->dhcp_buff, " init");
	  leasestream = popen(daemon->dhcp_buff, "r");
	}
      else
#endif
	{
          file_dirty = dns_dirty = 0;
          return;
        }

    }
  else
    {
      /* NOTE: need a+ mode to create file if it doesn't exist */
      leasestream = daemon->lease_stream = fopen(daemon->lease_file, "a+");
      
      if (!leasestream)
	die(_("cannot open or create lease file %s: %s"), daemon->lease_file, EC_FILE);
      
      /* a+ mode leaves pointer at end. */
      rewind(leasestream);
    }
  
#ifdef HAVE_DHCP6
 again:
#endif

  /* client-id max length is 255 which is 255*2 digits + 254 colons 
     borrow DNS packet buffer which is always larger than 1000 bytes */
  if (leasestream)
    while (fscanf(leasestream, "%lu %255s %64s %255s %764s",
		  &ei, daemon->dhcp_buff2, daemon->namebuff, 
		  daemon->dhcp_buff, daemon->packet) == 5)
      {
#ifdef HAVE_DHCP6
	if (!v6pass)
#endif
	  {
	    hw_len = parse_hex(daemon->dhcp_buff2, (unsigned char *)daemon->dhcp_buff2, DHCP_CHADDR_MAX, NULL, &hw_type);
	    /* For backwards compatibility, no explict MAC address type means ether. */
	    if (hw_type == 0 && hw_len != 0)
	      hw_type = ARPHRD_ETHER;
	  }

#ifdef HAVE_DHCP6
	if (v6pass)
	  inet_pton(AF_INET6, daemon->namebuff,	&addr.addr.addr6);
	else
#endif	
	  inet_pton(AF_INET, daemon->namebuff, &addr.addr.addr4);	

	clid_len = 0;
	if (strcmp(daemon->packet, "*") != 0)
	  clid_len = parse_hex(daemon->packet, (unsigned char *)daemon->packet, 255, NULL, NULL);
	
#ifdef HAVE_DHCP6
	if (v6pass)
	  lease = lease_allocate6(&addr.addr.addr6);
	else
#endif
	  lease = lease_allocate4(addr.addr.addr4);
	
	if (!lease)
	  die (_("too many stored leases"), NULL, EC_MISC);
       	
#ifdef HAVE_BROKEN_RTC
	if (ei != 0)
	  lease->expires = (time_t)ei + now;
	else
	  lease->expires = (time_t)0;
	lease->length = ei;
#else
	/* strictly time_t is opaque, but this hack should work on all sane systems,
	   even when sizeof(time_t) == 8 */
	lease->expires = (time_t)ei;
#endif

#ifdef HAVE_DHCP6
	if (!v6pass)
#endif
	  lease_set_hwaddr(lease, (unsigned char *)daemon->dhcp_buff2, (unsigned char *)daemon->packet, hw_len, hw_type, clid_len);
	
	if (strcmp(daemon->dhcp_buff, "*") !=  0)
	  lease_set_hostname(lease, daemon->dhcp_buff, 0);

	/* set these correctly: the "old" events are generated later from
	   the startup synthesised SIGHUP. */
	lease->new = lease->changed = 0;
      }

#ifdef HAVE_DHCP6  
  if (!v6pass)
    {
      if (fscanf(leasestream, "duid %255s", daemon->dhcp_buff) == 1)
	{
	  daemon->duid_len = parse_hex(daemon->dhcp_buff, (unsigned char *)daemon->dhcp_buff, 130, NULL, NULL);
	  daemon->duid = safe_malloc(daemon->duid_len);
	  memcpy(daemon->duid, daemon->dhcp_buff, daemon->duid_len );
	  v6pass = 1;
	  goto again;
	}
      
      /* If we're not doing DHCPv6, and there are not v6 leases, don't add the DUID to the database */
      if (daemon->dhcp6)
      	make_duid(now);
    }
#endif
  
#ifdef HAVE_SCRIPT
  if (!daemon->lease_stream)
    {
      int rc = 0;

      /* shell returns 127 for "command not found", 126 for bad permissions. */
      if (!leasestream || (rc = pclose(leasestream)) == -1 || WEXITSTATUS(rc) == 127 || WEXITSTATUS(rc) == 126)
	{
	  if (WEXITSTATUS(rc) == 127)
	    errno = ENOENT;
	  else if (WEXITSTATUS(rc) == 126)
	    errno = EACCES;
	  die(_("cannot run lease-init script %s: %s"), daemon->lease_change_command, EC_FILE);
	}
      
      if (WEXITSTATUS(rc) != 0)
	{
	  sprintf(daemon->dhcp_buff, "%d", WEXITSTATUS(rc));
	  die(_("lease-init script returned exit code %s"), daemon->dhcp_buff, WEXITSTATUS(rc) + EC_INIT_OFFSET);
	}
    }
#endif

  /* Some leases may have expired */
  file_dirty = 0;
  lease_prune(NULL, now);
  dns_dirty = 1;
}

void lease_update_from_configs(void)
{
  /* changes to the config may change current leases. */
  
  struct dhcp_lease *lease;
  struct dhcp_config *config;
  char *name;

  for (lease = leases; lease; lease = lease->next)
    if ((config = find_config(daemon->dhcp_conf, NULL, lease->clid, lease->clid_len, 
			      lease->hwaddr, lease->hwaddr_len, lease->hwaddr_type, NULL)) && 
	(config->flags & CONFIG_NAME) &&
	(!(config->flags & CONFIG_ADDR) || config->addr.s_addr == lease->addr.s_addr))
      lease_set_hostname(lease, config->hostname, 1);
    else if ((name = host_from_dns(lease->addr)))
      lease_set_hostname(lease, name, 1); /* updates auth flag only */
}

static void ourprintf(int *errp, char *format, ...)
{
  va_list ap;
  
  va_start(ap, format);
  if (!(*errp) && vfprintf(daemon->lease_stream, format, ap) < 0)
    *errp = errno;
  va_end(ap);
}

void lease_update_file(time_t now)
{
  struct dhcp_lease *lease;
  time_t next_event;
  int i, err = 0;

  if (file_dirty != 0 && daemon->lease_stream)
    {
      errno = 0;
      rewind(daemon->lease_stream);
      if (errno != 0 || ftruncate(fileno(daemon->lease_stream), 0) != 0)
	err = errno;
      
      for (lease = leases; lease; lease = lease->next)
	{

#ifdef HAVE_DHCP6
	  if (lease->is_ipv6)
	    continue;
#endif

#ifdef HAVE_BROKEN_RTC
	  ourprintf(&err, "%u ", lease->length);
#else
	  ourprintf(&err, "%lu ", (unsigned long)lease->expires);
#endif

	  if (lease->hwaddr_type != ARPHRD_ETHER || lease->hwaddr_len == 0) 
	    ourprintf(&err, "%.2x-", lease->hwaddr_type);
	  for (i = 0; i < lease->hwaddr_len; i++)
	    {
	      ourprintf(&err, "%.2x", lease->hwaddr[i]);
	      if (i != lease->hwaddr_len - 1)
		ourprintf(&err, ":");
	    }
	  
	  inet_ntop(AF_INET, &lease->addr, daemon->addrbuff, ADDRSTRLEN); 

	  ourprintf(&err, " %s ", daemon->addrbuff);
	  ourprintf(&err, "%s ", lease->hostname ? lease->hostname : "*");
	  	  
	  if (lease->clid && lease->clid_len != 0)
	    {
	      for (i = 0; i < lease->clid_len - 1; i++)
		ourprintf(&err, "%.2x:", lease->clid[i]);
	      ourprintf(&err, "%.2x\n", lease->clid[i]);
	    }
	  else
	    ourprintf(&err, "*\n");	  
	}
      
#ifdef HAVE_DHCP6  
      if (daemon->duid)
	{
	  ourprintf(&err, "duid ");
	  for (i = 0; i < daemon->duid_len - 1; i++)
	    ourprintf(&err, "%.2x:", daemon->duid[i]);
	  ourprintf(&err, "%.2x\n", daemon->duid[i]);
	  
	  for (lease = leases; lease; lease = lease->next)
	    {
	      
	      if (!lease->is_ipv6)
		continue;

#ifdef HAVE_BROKEN_RTC
	      ourprintf(&err, "%u ", lease->length);
#else
	      ourprintf(&err, "%lu ", (unsigned long)lease->expires);
#endif
    
	      inet_ntop(AF_INET6, lease->hwaddr, daemon->addrbuff, ADDRSTRLEN);
	 
	      ourprintf(&err, "* %s ", daemon->addrbuff);
	      ourprintf(&err, "%s ", lease->hostname ? lease->hostname : "*");
	      
	      if (lease->clid && lease->clid_len != 0)
		{
		  for (i = 0; i < lease->clid_len - 1; i++)
		    ourprintf(&err, "%.2x:", lease->clid[i]);
		  ourprintf(&err, "%.2x\n", lease->clid[i]);
		}
	      else
		ourprintf(&err, "*\n");	  
	    }
	}
#endif      
	  
      if (fflush(daemon->lease_stream) != 0 ||
	  fsync(fileno(daemon->lease_stream)) < 0)
	err = errno;
      
      if (!err)
	file_dirty = 0;
    }
  
  /* Set alarm for when the first lease expires + slop. */
  for (next_event = 0, lease = leases; lease; lease = lease->next)
    if (lease->expires != 0 &&
	(next_event == 0 || difftime(next_event, lease->expires + 10) > 0.0))
      next_event = lease->expires + 10;
   
  if (err)
    {
      if (next_event == 0 || difftime(next_event, LEASE_RETRY + now) > 0.0)
	next_event = LEASE_RETRY + now;
      
      my_syslog(MS_DHCP | LOG_ERR, _("failed to write %s: %s (retry in %us)"), 
		daemon->lease_file, strerror(err),
		(unsigned int)difftime(next_event, now));
    }

  if (next_event != 0)
    alarm((unsigned)difftime(next_event, now)); 
}

void lease_update_dns(void)
{
  struct dhcp_lease *lease;
  
  if (daemon->port != 0 && dns_dirty)
    {
      cache_unhash_dhcp();
      
      for (lease = leases; lease; lease = lease->next)
	{
	  if (lease->fqdn)
	    cache_add_dhcp_entry(lease->fqdn, &lease->addr, lease->expires);
	     
	  if (!option_bool(OPT_DHCP_FQDN) && lease->hostname)
	    cache_add_dhcp_entry(lease->hostname, &lease->addr, lease->expires);
	}
      
      dns_dirty = 0;
    }
}

void lease_prune(struct dhcp_lease *target, time_t now)
{
  struct dhcp_lease *lease, *tmp, **up;

  for (lease = leases, up = &leases; lease; lease = tmp)
    {
      tmp = lease->next;
      if ((lease->expires != 0 && difftime(now, lease->expires) > 0) || lease == target)
	{
	  file_dirty = 1;
	  if (lease->hostname)
	    dns_dirty = 1;
	  
 	  *up = lease->next; /* unlink */
	  
	  /* Put on old_leases list 'till we
	     can run the script */
	  lease->next = old_leases;
	  old_leases = lease;
	  
	  leases_left++;
	}
      else
	up = &lease->next;
    }
} 
	
  
struct dhcp_lease *lease_find_by_client(unsigned char *hwaddr, int hw_len, int hw_type,
					unsigned char *clid, int clid_len)
{
  struct dhcp_lease *lease;

  if (clid)
    for (lease = leases; lease; lease = lease->next)
      {
#ifdef HAVE_DHCP6
	if (lease->is_ipv6)
	  continue;
#endif
	if (lease->clid && clid_len == lease->clid_len &&
	    memcmp(clid, lease->clid, clid_len) == 0)
	  return lease;
      }
  
  for (lease = leases; lease; lease = lease->next)	
    {
#ifdef HAVE_DHCP6
      if (lease->is_ipv6)
	continue;
#endif   
      if ((!lease->clid || !clid) && 
	  hw_len != 0 && 
	  lease->hwaddr_len == hw_len &&
	  lease->hwaddr_type == hw_type &&
	  memcmp(hwaddr, lease->hwaddr, hw_len) == 0)
	return lease;
    }

  return NULL;
}

struct dhcp_lease *lease_find_by_addr(struct in_addr addr)
{
  struct dhcp_lease *lease;

  for (lease = leases; lease; lease = lease->next)
    {
#ifdef HAVE_DHCP6
      if (lease->is_ipv6)
	continue;
#endif  
      if (lease->addr.s_addr == addr.s_addr)
	return lease;
    }

  return NULL;
}

/* Find largest assigned address in context */
struct in_addr lease_find_max_addr(struct dhcp_context *context)
{
  struct dhcp_lease *lease;
  struct in_addr addr = context->start;
  
  if (!(context->flags & (CONTEXT_STATIC | CONTEXT_PROXY)))
    for (lease = leases; lease; lease = lease->next)
      {
#ifdef HAVE_DHCP6
	if (lease->is_ipv6)
	  continue;
#endif
	if (((unsigned)ntohl(lease->addr.s_addr)) > ((unsigned)ntohl(context->start.s_addr)) &&
	    ((unsigned)ntohl(lease->addr.s_addr)) <= ((unsigned)ntohl(context->end.s_addr)) &&
	    ((unsigned)ntohl(lease->addr.s_addr)) > ((unsigned)ntohl(addr.s_addr)))
	  addr = lease->addr;
      }
  
  return addr;
}

static struct dhcp_lease *lease_allocate(void)
{
  struct dhcp_lease *lease;
  if (!leases_left || !(lease = whine_malloc(sizeof(struct dhcp_lease))))
    return NULL;

  memset(lease, 0, sizeof(struct dhcp_lease));
  lease->new = 1;
  lease->expires = 1;
#ifdef HAVE_BROKEN_RTC
  lease->length = 0xffffffff; /* illegal value */
#endif
  lease->next = leases;
  leases = lease;
  
  file_dirty = 1;
  leases_left--;

  return lease;
}

struct dhcp_lease *lease_allocate4(struct in_addr addr)
{
  struct dhcp_lease *lease = lease_allocate();
  lease->addr = addr;
  lease->hwaddr_len = 256; /* illegal value */

  return lease;
}

#ifdef HAVE_DHCP6
struct dhcp_lease *lease_allocate6(struct in6_addr *addrp)
{
  struct dhcp_lease *lease = lease_allocate();
  memcpy(lease->hwaddr, addrp, sizeof(*addrp)) ;
  lease->is_ipv6 = 1;

  return lease;
}
#endif

void lease_set_expires(struct dhcp_lease *lease, unsigned int len, time_t now)
{
  time_t exp = now + (time_t)len;
  
  if (len == 0xffffffff)
    {
      exp = 0;
      len = 0;
    }
  
  if (exp != lease->expires)
    {
      dns_dirty = 1;
      lease->expires = exp;
#ifndef HAVE_BROKEN_RTC
      lease->aux_changed = file_dirty = 1;
#endif
    }
  
#ifdef HAVE_BROKEN_RTC
  if (len != lease->length)
    {
      lease->length = len;
      lease->aux_changed = file_dirty = 1; 
    }
#endif
} 

void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr,
		      unsigned char *clid, int hw_len, int hw_type, int clid_len)
{
  if (hw_len != lease->hwaddr_len ||
      hw_type != lease->hwaddr_type || 
      (hw_len != 0 && memcmp(lease->hwaddr, hwaddr, hw_len) != 0))
    {
      memcpy(lease->hwaddr, hwaddr, hw_len);
      lease->hwaddr_len = hw_len;
      lease->hwaddr_type = hw_type;
      lease->changed = file_dirty = 1; /* run script on change */
    }

  /* only update clid when one is available, stops packets
     without a clid removing the record. Lease init uses
     clid_len == 0 for no clid. */
  if (clid_len != 0 && clid)
    {
      if (!lease->clid)
	lease->clid_len = 0;

      if (lease->clid_len != clid_len)
	{
	  lease->aux_changed = file_dirty = 1;
	  free(lease->clid);
	  if (!(lease->clid = whine_malloc(clid_len)))
	    return;
	}
      else if (memcmp(lease->clid, clid, clid_len) != 0)
	lease->aux_changed = file_dirty = 1;
	  
      lease->clid_len = clid_len;
      memcpy(lease->clid, clid, clid_len);
    }

}

static void kill_name(struct dhcp_lease *lease)
{
  /* run script to say we lost our old name */
  
  /* this shouldn't happen unless updates are very quick and the
     script very slow, we just avoid a memory leak if it does. */
  free(lease->old_hostname);
  
  /* If we know the fqdn, pass that. The helper will derive the
     unqualified name from it, free the unqulaified name here. */

  if (lease->fqdn)
    {
      lease->old_hostname = lease->fqdn;
      free(lease->hostname);
    }
  else
    lease->old_hostname = lease->hostname;

  lease->hostname = lease->fqdn = NULL;
}

void lease_set_hostname(struct dhcp_lease *lease, char *name, int auth)
{
  struct dhcp_lease *lease_tmp;
  char *new_name = NULL, *new_fqdn = NULL;
  
  if (lease->hostname && name && hostname_isequal(lease->hostname, name))
    {
      lease->auth_name = auth;
      return;
    }
  
  if (!name && !lease->hostname)
    return;

  /* If a machine turns up on a new net without dropping the old lease,
     or two machines claim the same name, then we end up with two interfaces with
     the same name. Check for that here and remove the name from the old lease.
     Don't allow a name from the client to override a name from dnsmasq config. */
  
  if (name)
    {
      if ((new_name = whine_malloc(strlen(name) + 1)))
	{
	  char *suffix = get_domain(lease->addr);
	  strcpy(new_name, name);
	  if (suffix && (new_fqdn = whine_malloc(strlen(new_name) + strlen(suffix) + 2)))
	    {
	      strcpy(new_fqdn, name);
	      strcat(new_fqdn, ".");
	      strcat(new_fqdn, suffix);
	    }
	}
	  
      /* Depending on mode, we check either unqualified name or FQDN. */
      for (lease_tmp = leases; lease_tmp; lease_tmp = lease_tmp->next)
	{
	  if (option_bool(OPT_DHCP_FQDN))
	    {
	      if (!new_fqdn || !lease_tmp->fqdn || !hostname_isequal(lease_tmp->fqdn, new_fqdn) )
		continue;
	    }
	  else
	    {
	      if (!new_name || !lease_tmp->hostname || !hostname_isequal(lease_tmp->hostname, new_name) )
		continue; 
	    }
	  
	  if (lease_tmp->auth_name && !auth)
	    {
	      free(new_name);
	      free(new_fqdn);
	      return;
	    }
	
	  kill_name(lease_tmp);
	  break;
	}
    }

  if (lease->hostname)
    kill_name(lease);

  lease->hostname = new_name;
  lease->fqdn = new_fqdn;
  lease->auth_name = auth;
  
  file_dirty = 1;
  dns_dirty = 1; 
  lease->changed = 1; /* run script on change */
}

void lease_set_interface(struct dhcp_lease *lease, int interface)
{
  if (lease->last_interface == interface)
    return;

  lease->last_interface = interface;
  lease->changed = 1;
}

void rerun_scripts(void)
{
  struct dhcp_lease *lease;
  
  for (lease = leases; lease; lease = lease->next)
    lease->changed = 1;
}

/* deleted leases get transferred to the old_leases list.
   remove them here, after calling the lease change
   script. Also run the lease change script on new/modified leases.

   Return zero if nothing to do. */
int do_script_run(time_t now)
{
  struct dhcp_lease *lease;

#ifdef HAVE_DBUS
  /* If we're going to be sending DBus signals, but the connection is not yet up,
     delay everything until it is. */
  if (option_bool(OPT_DBUS) && !daemon->dbus)
    return 0;
#endif

  if (old_leases)
    {
      lease = old_leases;
                  
      /* If the lease still has an old_hostname, do the "old" action on that first */
      if (lease->old_hostname)
	{
#ifdef HAVE_SCRIPT
	  queue_script(ACTION_OLD_HOSTNAME, lease, lease->old_hostname, now);
#endif
	  free(lease->old_hostname);
	  lease->old_hostname = NULL;
	  return 1;
	}
      else 
	{
	  kill_name(lease);
#ifdef HAVE_SCRIPT
	  queue_script(ACTION_DEL, lease, lease->old_hostname, now);
#endif
#ifdef HAVE_DBUS
	  emit_dbus_signal(ACTION_DEL, lease, lease->old_hostname);
#endif
	  old_leases = lease->next;
	  
	  free(lease->old_hostname); 
	  free(lease->clid);
	  free(lease->extradata);
	  free(lease);
	    
	  return 1; 
	}
    }
  
  /* make sure we announce the loss of a hostname before its new location. */
  for (lease = leases; lease; lease = lease->next)
    if (lease->old_hostname)
      {	
#ifdef HAVE_SCRIPT
	queue_script(ACTION_OLD_HOSTNAME, lease, lease->old_hostname, now);
#endif
	free(lease->old_hostname);
	lease->old_hostname = NULL;
	return 1;
      }
  
  for (lease = leases; lease; lease = lease->next)
    if (lease->new || lease->changed || 
	(lease->aux_changed && option_bool(OPT_LEASE_RO)))
      {
#ifdef HAVE_SCRIPT
	queue_script(lease->new ? ACTION_ADD : ACTION_OLD, lease, 
		     lease->fqdn ? lease->fqdn : lease->hostname, now);
#endif
#ifdef HAVE_DBUS
	emit_dbus_signal(lease->new ? ACTION_ADD : ACTION_OLD, lease,
			 lease->fqdn ? lease->fqdn : lease->hostname);
#endif
	lease->new = lease->changed = lease->aux_changed = 0;
	
	/* this is used for the "add" call, then junked, since they're not in the database */
	free(lease->extradata);
	lease->extradata = NULL;
	
	return 1;
      }

  return 0; /* nothing to do */
}

#endif