"deprecated" lease-time keyword for IPv6

CHANGELOG

@@ -55,6 +55,18 @@ version 2.61
 	    received from a network which has no valid dhcp-range.
 	    Thanks to Stephane Glondu for the bug report.
 
+	    Add a new DHCP lease time keyword, "deprecated" for
+	    --dhcp-range. This is only valid for IPv6, and sets the
+	    preffered lease time for both DHCP and RA to zero. The
+	    effect is that clients can continue to use the address 
+	    for existing connections, but new connections will use
+            other addresses, if they exist. This makes hitless
+	    renumbering at least possible.
+
+	    Fix bug in address6_available() which caused DHCPv6 lease
+	    aquistion to fail of more than one dhcp-range in use.
+	    
+
  
 version 2.60
             Fix compilation problem in Mac OS X Lion. Thanks to Olaf

dnsmasq.conf.example

@@ -169,14 +169,32 @@
 # hosts. Use the DHCPv4 lease to derive the name, network segment and 
 # MAC address and assume that the host will also have an
 # IPv6 address calculated using the SLAAC alogrithm.
-# This will generate an erroneous AAAA record if a host is using privacy 
-# extensions or does not support IPv6. Use with care.
 #dhcp-range=1234::, ra-names
 
 # Do Router Advertisements, BUT NOT DHCP for this subnet.
 # Set the lifetime to 46 hours. (Note: minimum lifetime is 2 hours.)
 #dhcp-range=1234::, ra-only, 48h
 
+# Do DHCP and Router Advertisements for this subnet. Set the A bit in the RA
+# so that clients can use SLAAC addresses as well as DHCP ones.
+#dhcp-range=1234::2, 1234::500, slaac
+
+# Do Router Advertisements and stateless DHCP for this subnet. Clients will
+# not get addresses from DHCP, but they will get other configuration information.
+# They will use SLAAC for addresses.
+#dhcp-range=1234::, ra-stateless
+
+# Do stateless DHCP, SLAAC, and generate DNS names for SLAAC addresses
+# from DHCPv4 leases.
+#dhcp-range=1234::, ra-stateless, ra-names
+
+# Do router advertisements for all subnets where we're doing DHCPv6
+# Unless overriden by ra-stateless, ra-names, et al, the router 
+# advertisements will have the M and O bits set, so that the clients
+# get addresses and configuration from DHCPv6, and the A bit reset, so the 
+# clients don't use SLAAC addresses.
+#enable-ra
+
 # Supply parameters for specified hosts using DHCP. There are lots
 # of valid alternatives, so we will give examples of each. Note that
 # IP addresses DO NOT have to be in the range given above, they just

man/dnsmasq.8

@@ -510,9 +510,9 @@ compiled in and the kernel must have conntrack support
 included and configured. This option cannot be combined with
 --query-port. 
 .TP
-.B \-F, --dhcp-range=[interface:<interface>,][tag:<tag>[,tag:<tag>],][set:<tag],]<start-addr>,<end-addr>[,<netmask>[,<broadcast>]][,<lease time>]
+.B \-F, --dhcp-range=[interface:<interface>,][tag:<tag>[,tag:<tag>],][set:<tag],]<start-addr>[,<end-addr>][,<mode>][,<netmask>[,<broadcast>]][,<lease time>]
 .TP
-.B \-F, --dhcp-range=[interface:<interface>,][tag:<tag>[,tag:<tag>],][set:<tag],]<start-IPv6addr>,<end-IPv6addr>[,<prefix-len>][,<lease time>]
+.B \-F, --dhcp-range=[interface:<interface>,][tag:<tag>[,tag:<tag>],][set:<tag],]<start-IPv6addr>[,<end-IPv6addr>][,<mode>][,<prefix-len>][,<lease time>]
 
 Enable the DHCP server. Addresses will be given out from the range
 <start-addr> to <end-addr> and from statically defined addresses given
@@ -522,8 +522,12 @@ options. If the lease time is given, then leases
 will be given for that length of time. The lease time is in seconds,
 or minutes (eg 45m) or hours (eg 1h) or "infinite". If not given,
 the default lease time is one hour. The
-minimum lease time is two minutes. This
-option may be repeated, with different addresses, to enable DHCP
+minimum lease time is two minutes. For IPv6 ranges, the lease time
+maybe "deprecated"; this sets the preferred lifetime sent in a DHCP
+lease or router advertisement to zero, which causes clients to use
+other addresses, if available, for new connections as a prelude to renumbering.
+
+This option may be repeated, with different addresses, to enable DHCP
 service to more than one network. For directly connected networks (ie,
 networks on which the machine running dnsmasq has an interface) the
 netmask is optional: dnsmasq will determine it from the interface
@@ -548,7 +552,7 @@ When it is prefixed with 'tag:' instead, then its meaning changes from setting
 a tag to matching it. Only one tag may be set, but more than one tag
 may be matched.
 
-The end address may be replaced by the keyword 
+The optional <mode> keyword may be 
 .B static
 which tells dnsmasq to enable DHCP for the network specified, but not
 to dynamically allocate IP addresses: only hosts which have static
@@ -556,25 +560,36 @@ addresses given via
 .B dhcp-host
 or from /etc/ethers will be served. 
 
-The end address may be replaced by
-the keyword
+Fot IPv4, the <mode> may be 
 .B proxy
 in which case dnsmasq will provide proxy-DHCP on the specified
 subnet. (See 
 .B pxe-prompt
 and 
 .B pxe-service
-for details, applies to IPv4 only.)
+for details.)
+
+For IPv6, the mode may be some combination of
+.B ra-only, slaac, ra-names, ra-stateless.
 
-The end address may be replaced by
-the keyword
 .B ra-only
-which tells dnsmasq to offer Router Advertisement only on this subnet,
-and not DHCP. This applies to IPv6 only, see
-.B enable-ra
-for details. Instead, the keyword
+tells dnsmasq to offer Router Advertisement only on this subnet,
+and not DHCP. 
+
+.B slaac
+tells dnsmasq to offer Router Advertisement on this subnet and to set
+the A bit in the router advertisement, so that the client will use
+SLAAC addresses. When used with a DHCP range or static DHCP address
+this results in the client having both a DHCP-assigned and a SLAAC
+address.
+
+.B ra-stateless
+sends router advertisements with the O and A bits set, and provides a
+stateless DHCP service. The client will use a SLAAC address, and use
+DHCP for other configuration information.
+
 .B ra-names
-may be used. This does the same at ra-only, but also enables a mode
+enables a mode
 which gives DNS names to dual-stack hosts which do SLAAC for
 IPv6. Dnsmasq uses the host's IPv4 lease to derive the name, network
 segment and MAC address and assumes that the host will also have an
@@ -584,6 +599,11 @@ record is added to the DNS for this IPv6
 address. Note that this is only happens for directly-connected
 networks, (not one doing DHCP via a relay) and it will not work 
 if a host is using privacy extensions. 
+.B ra-names
+can be combined  with 
+.B ra-stateless
+and
+.B slaac.
 
 The interface:<interface name> section is not normally used. See the
 NOTES section for details of this.
@@ -1319,20 +1339,10 @@ only a subset of this is needed, and dnsmasq can handle it, using
 existing DHCP configuration to provide most data. When RA is enabled,
 dnsmasq will advertise a prefix for each dhcp-range, with default
 router and recursive DNS server as the relevant link-local address on 
-the machine running dnsmasq. The "managed address" bits are set, and
-the "use SLAAC" bit is reset, except for a dhcp-range which is 
-marked as "ra-only" or "ra-names", in which case RA is provided but no 
-DHCPv6 service and the managed address bits are
-cleared and the "use SLAAC" bit set. If the same subnet appears in a
-normal dhcp-range and an "ra-only" dhcp-range, then the "managed
-address" bits and the "use SLAAC" bits are all set, allowing SLAAC and
-DHCP address to co-exist on the same subnet.  
-.B enable-ra
-enables router advertisement for prefixes where dnsmasq is doing
-DHCPv6. It is not needed for "ra-only" prefixes. Creating an "ra-only"
-prefix and not setting 
-.B enable-ra
-sends advertisements only to "ra-only" prefixes. 
+the machine running dnsmasq. By default, he "managed address" bits are set, and
+the "use SLAAC" bit is reset. This can be changed for individual
+subnets with the mode keywords described in
+.B --dhcp-range.
 .TP
 .B --enable-tftp[=<interface>]
 Enable the TFTP server function. This is deliberately limited to that

src/config.h

@@ -167,7 +167,7 @@ HAVE_SOLARIS_NETWORK
    define exactly one of these to alter interaction with kernel networking.
 
 HAVE_GETOPT_LONG
-   defined when GNU-sty;e getopt_long available. 
+   defined when GNU-style getopt_long available. 
 
 HAVE_ARC4RANDOM
    defined if arc4random() available to get better security from DNS spoofs

src/dhcp6.c

@@ -229,7 +229,7 @@ int address6_allocate(struct dhcp_context *context,  unsigned char *clid, int cl
   
   for (pass = 0; pass <= 1; pass++)
     for (c = context; c; c = c->current)
-      if (c->flags & (CONTEXT_STATIC | CONTEXT_RA_STATELESS))
+      if (c->flags & (CONTEXT_DEPRECATE | CONTEXT_STATIC | CONTEXT_RA_STATELESS))
 	continue;
       else if (!match_netid(c->filter, netids, pass))
 	continue;
@@ -282,9 +282,9 @@ struct dhcp_context *address6_available(struct dhcp_context *context,
       start = addr6part(&tmp->start6);
       end = addr6part(&tmp->end6);
 
-      if (!(tmp->flags & (CONTEXT_STATIC | CONTEXT_PROXY)) &&
-          is_same_net6(&context->start6, taddr, context->prefix) &&
-	  is_same_net6(&context->end6, taddr, context->prefix) &&
+      if (!(tmp->flags & (CONTEXT_STATIC | CONTEXT_RA_STATELESS)) &&
+          is_same_net6(&tmp->start6, taddr, tmp->prefix) &&
+	  is_same_net6(&tmp->end6, taddr, tmp->prefix) &&
 	  addr >= start &&
           addr <= end &&
           match_netid(tmp->filter, netids, 1))

src/dnsmasq.c

@@ -530,7 +530,7 @@ int main (int argc, char **argv)
     my_syslog(MS_DHCP | LOG_INFO, _("IPv6 router advertisement enabled"));
 
 #ifdef HAVE_DHCP
-  if (daemon->dhcp || daemon->dhcp6)
+  if (daemon->dhcp || daemon->dhcp6 || daemon->ra_contexts)
     {
       struct dhcp_context *dhcp_tmp;
       int family = AF_INET;
@@ -543,7 +543,7 @@ int main (int argc, char **argv)
 	{
 	  void *start = &dhcp_tmp->start;
 	  void *end = &dhcp_tmp->end;
-	  
+	  	  
 #ifdef HAVE_DHCP6
 	  if (family == AF_INET6)
 	    {
@@ -551,28 +551,48 @@ int main (int argc, char **argv)
 	      end = &dhcp_tmp->end6;
 	      struct in6_addr subnet = dhcp_tmp->start6;
 	      setaddr6part(&subnet, 0);
-	      inet_ntop(AF_INET6, &subnet, daemon->dhcp_buff2, 256);
+	      inet_ntop(AF_INET6, &subnet, daemon->addrbuff, 256);
 	    }
 #endif
 	  
-	  prettyprint_time(daemon->namebuff, dhcp_tmp->lease_time);
-	  inet_ntop(family, start, daemon->dhcp_buff, 256);
-	  inet_ntop(family, end, daemon->dhcp_buff3, 256);
+	  if (family != AF_INET && (dhcp_tmp->flags & CONTEXT_DEPRECATE))
+	    strcpy(daemon->namebuff, _("prefix deprecated"));
+	  else
+	    {
+	      char *p = daemon->namebuff;
+	      p += sprintf(p, _("lease time "));
+	      prettyprint_time(p, dhcp_tmp->lease_time);
+	    }
+	  
+	  if (daemon->dhcp_buff)
+	    inet_ntop(family, start, daemon->dhcp_buff, 256);
+	  if (daemon->dhcp_buff3)
+	    inet_ntop(family, end, daemon->dhcp_buff3, 256);
 	  if ((dhcp_tmp->flags & CONTEXT_DHCP) || family == AF_INET) 
 	    my_syslog(MS_DHCP | LOG_INFO, 
-		      (dhcp_tmp->flags & CONTEXT_STATIC) ? 
-		      _("DHCP, static leases only on %.0s%s, lease time %s") :
 		      (dhcp_tmp->flags & CONTEXT_RA_STATELESS) ? 
-		      _("SLAAC and stateless DHCPv6 on %.0s%s%.0s") :
+		      _("stateless DHCPv6 on %s%.0s%.0s") :
+		      (dhcp_tmp->flags & CONTEXT_STATIC) ? 
+		      _("DHCP, static leases only on %.0s%s, %s") :
 		      (dhcp_tmp->flags & CONTEXT_PROXY) ?
 		      _("DHCP, proxy on subnet %.0s%s%.0s") :
-		      _("DHCP, IP range %s -- %s, lease time %s"),
+		      _("DHCP, IP range %s -- %s, %s"),
 		      daemon->dhcp_buff, daemon->dhcp_buff3, daemon->namebuff);
+
 	  if (dhcp_tmp->flags & CONTEXT_RA_NAME)
-	    my_syslog(MS_DHCP | LOG_INFO, _("SLAAC and DHCPv4-derived names on %s"), daemon->dhcp_buff2);
-	  if (dhcp_tmp->flags & CONTEXT_RA_ONLY)
-	    my_syslog(MS_DHCP | LOG_INFO, _("SLAAC on %s"), daemon->dhcp_buff2);
- 
+	    my_syslog(MS_DHCP | LOG_INFO, _("DHCPv4-derived IPv6 names on %s"), 
+		      daemon->addrbuff);
+	  if (dhcp_tmp->flags & (CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS))
+	    {
+	      if (!(dhcp_tmp->flags & CONTEXT_DEPRECATE))
+		{
+		  char *p = daemon->namebuff;
+		  p += sprintf(p, _("prefix valid "));
+		  prettyprint_time(p, dhcp_tmp->lease_time > 7200 ? dhcp_tmp->lease_time : 7200);
+		}
+	      my_syslog(MS_DHCP | LOG_INFO, _("SLAAC on %s %s"), 
+			daemon->addrbuff, daemon->namebuff);
+	    }
 	}
       
 #ifdef HAVE_DHCP6

src/dnsmasq.h

@@ -655,6 +655,7 @@ struct dhcp_context {
 #define CONTEXT_RA_NAME       64
 #define CONTEXT_RA_STATELESS 128
 #define CONTEXT_DHCP         256
+#define CONTEXT_DEPRECATE    512
 
 struct ping_result {
   struct in_addr addr;

src/option.c

@@ -2118,6 +2118,8 @@ static char *one_opt(int option, char *arg, char *gen_prob, int command_line)
 	  {
 	    if (strcmp(a[leasepos], "infinite") == 0)
 	      new->lease_time = 0xffffffff;
+	    else if (strcmp(a[leasepos], "deprecated") == 0)
+	      new->flags |= CONTEXT_DEPRECATE;
 	    else
 	      {
 		int fac = 1;
@@ -2150,16 +2152,6 @@ static char *one_opt(int option, char *arg, char *gen_prob, int command_line)
 		  }
 	      }
 	  }
-
-#ifdef HAVE_DHCP6
-	/* lifetimes must be min 2 hrs, by RFC 2462.
-	   This gets enforced in radv.c for DHCP ranges
-	   which are legitimately less. */
-	if ((new->flags & CONTEXT_RA_ONLY) &&
-	    new->lease_time < 7200)
-	  new->lease_time = 7200;
-#endif
-	    
 	break;
       }
 

src/radv.c

@@ -276,9 +276,8 @@ static void send_ra(int iface, char *iface_name, struct in6_addr *dest)
 static int add_prefixes(struct in6_addr *local,  int prefix,
 			int scope, int if_index, int dad, void *vparam)
 {
-  struct dhcp_context *context, *tmp;
+  struct dhcp_context *context;
   struct ra_param *param = vparam;
-  struct prefix_opt *opt;
 
   (void)scope; /* warning */
   (void)dad;
@@ -291,13 +290,17 @@ static int add_prefixes(struct in6_addr *local,  int prefix,
 	       !IN6_IS_ADDR_LINKLOCAL(local) &&
 	       !IN6_IS_ADDR_MULTICAST(local))
 	{
+	  int do_slaac = 0;
+	  int deprecate  = 0;
+	  unsigned int time = 0xffffffff;
+	  struct in6_addr *addr = NULL;
+	  struct prefix_opt *opt;
+
 	  for (context = daemon->ra_contexts; context; context = context->next)
 	    if (prefix == context->prefix &&
 		is_same_net6(local, &context->start6, prefix) &&
 		is_same_net6(local, &context->end6, prefix))
 	      {
-		int do_slaac = 0;
-
 		if ((context->flags & 
 		     (CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS)))
 		  {
@@ -314,68 +317,51 @@ static int add_prefixes(struct in6_addr *local,  int prefix,
 		    param->other = 1;
 		  }
 
-		if (context->flags & CONTEXT_RA_DONE)
-		  continue;
+		/* find floor time */
+		if (time > context->lease_time)
+		  time = context->lease_time;
 		
-		/* subsequent prefixes on the same interface don't need timers */
+		if (context->flags & CONTEXT_DEPRECATE)
+		  deprecate = 1;
+
+		/* subsequent prefixes on the same interface 
+		   and subsequent instances of this prefix don't need timers */
 		if (!param->first)
 		  context->ra_time = 0;
 		param->first = 0;
 		param->found_context = 1;
-		context->flags |= CONTEXT_RA_DONE;
-
-		/* mark this subnet and duplicates: as done. */
-		for (tmp = context->next; tmp; tmp = tmp->next)
-		  if (tmp->prefix == prefix &&
-		      is_same_net6(local, &tmp->start6, prefix) &&
-		      is_same_net6(local, &tmp->end6, prefix))
-		    {
-		      tmp->flags |= CONTEXT_RA_DONE;
-		      context->ra_time = 0;
-		      /* if any dhcp-range with ra-only on this subnet
-			 set the "do_slaac" bit */
-		      if (tmp->flags & 
-			  (CONTEXT_RA_ONLY | CONTEXT_RA_NAME | CONTEXT_RA_STATELESS))
-			{
-			  do_slaac = 1;
-			  if (context->flags & CONTEXT_RA_STATELESS)
-			    param->other = 1; 
-			}
-		      else
-			{
-			  /* don't do RA for non-ra-only unless --enable-ra is set */
-			  if (!option_bool(OPT_RA))
-			    continue;
-			  param->managed = 1;
-			  param->other = 1;
-			}
-		    }
 		
-		if ((opt = expand(sizeof(struct prefix_opt))))
-		  {
-		    u64 addrpart = addr6part(&context->start6);
-		    u64 mask = (prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU;
-		    unsigned int time = context->lease_time;
-
-		    /* lifetimes must be min 2 hrs, by RFC 2462 */
-		    if (time < 7200)
-		      time = 7200;
-
-		    opt->type = ICMP6_OPT_PREFIX;
-		    opt->len = 4;
-		    opt->prefix_len = prefix;
-		    /* autonomous only is we're not doing dhcp */
-		    opt->flags = do_slaac ? 0x40 : 0x00;
-		    opt->valid_lifetime = opt->preferred_lifetime = htonl(time);
-		    opt->reserved = 0;
-		    
-		    opt->prefix = context->start6;
-		    setaddr6part(&opt->prefix, addrpart & ~mask);
-		    
-		    inet_ntop(AF_INET6, &opt->prefix, daemon->addrbuff, ADDRSTRLEN);
-		    my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff); 		    
-		  }
+		if (context->flags & CONTEXT_RA_DONE)
+		  continue;
+		
+		context->flags |= CONTEXT_RA_DONE;
+		addr = &context->start6;
 	      }
+		
+	  if (addr && (opt = expand(sizeof(struct prefix_opt))))
+	    {
+	      u64 addrpart = addr6part(addr);
+	      u64 mask = (prefix == 64) ? (u64)-1LL : (1LLU << (128 - prefix)) - 1LLU;
+	      
+	      /* lifetimes must be min 2 hrs, by RFC 2462 */
+	      if (time < 7200)
+		time = 7200;
+	      
+	      opt->type = ICMP6_OPT_PREFIX;
+	      opt->len = 4;
+	      opt->prefix_len = prefix;
+	      /* autonomous only is we're not doing dhcp */
+	      opt->flags = do_slaac ? 0x40 : 0x00;
+	      opt->valid_lifetime = htonl(time);
+	      opt->preferred_lifetime = htonl(deprecate ? 0 : time);
+	      opt->reserved = 0;
+	      
+	      opt->prefix = *addr;
+	      setaddr6part(&opt->prefix, addrpart & ~mask);
+			
+	      inet_ntop(AF_INET6, &opt->prefix, daemon->addrbuff, ADDRSTRLEN);
+	      my_syslog(MS_DHCP | LOG_INFO, "RTR-ADVERT(%s) %s", param->if_name, daemon->addrbuff); 		    
+	    }
 	}
     }          
   return 1;

src/rfc3315.c

@@ -513,13 +513,13 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	    while (1)
 	      {
 		struct in6_addr alloced_addr, *addrp = NULL;
-		u32 preferred_time = 0;
+		u32 requested_time = 0;
 		struct dhcp_lease *lease = NULL;
 		
 		if (ia_option)
 		  {
 		    struct in6_addr *req_addr = opt6_ptr(ia_option, 0);
-		    preferred_time = opt6_uint(ia_option, 16, 4);
+		    requested_time = opt6_uint(ia_option, 16, 4);
 		    
 		    if (!address6_available(context, req_addr, tags) &&
 			(!have_config(config, CONFIG_ADDR6) || memcmp(&config->addr6, req_addr, IN6ADDRSZ) != 0))
@@ -621,10 +621,10 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 			
 			if (ia_option)
 			  {
-			    if (preferred_time < 120u )
-			      preferred_time = 120u; /* sanity */
-			    if (lease_time == 0xffffffff || (preferred_time != 0xffffffff && preferred_time < lease_time))
-			      lease_time = preferred_time;
+			    if (requested_time < 120u )
+			      requested_time = 120u; /* sanity */
+			    if (lease_time == 0xffffffff || (requested_time != 0xffffffff && requested_time < lease_time))
+			      lease_time = requested_time;
 			  }
 			  
 			if (lease_time < min_time)
@@ -730,8 +730,9 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 			  {
 			    o1 =  new_opt6(OPTION6_IAADDR);
 			    put_opt6(addrp, sizeof(*addrp));
-			    put_opt6_long(lease_time);
-			    put_opt6_long(lease_time);
+			    /* preferred lifetime */
+			    put_opt6_long(this_context && (this_context->flags & CONTEXT_DEPRECATE) ? 0 : lease_time);
+			    put_opt6_long(lease_time); /* valid lifetime */
 			    end_opt6(o1);
 
 			    log6_packet( make_lease ? "DHCPREPLY" : "DHCPADVERTISE", 
@@ -842,7 +843,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 	      {
 		struct dhcp_lease *lease = NULL;
 		struct in6_addr *req_addr = opt6_ptr(ia_option, 0);
-		u32 preferred_time = opt6_uint(ia_option, 16, 4);
+		u32 requested_time = opt6_uint(ia_option, 16, 4);
 		unsigned int lease_time;
 		struct dhcp_context *this_context;
 		struct dhcp_config *valid_config = config;
@@ -873,7 +874,10 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		
 		if (!address6_available(context, req_addr, tagif) || 
 		    !(this_context = narrow_context6(context, req_addr, tagif)))
-		  lease_time = 0;
+		  {
+		    lease_time = 0;
+		    this_context = NULL;
+		  }
 		else
 		  {
 		    /* get tags from context if we've not used it before */
@@ -895,10 +899,10 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		    
 		    lease_time = have_config(valid_config, CONFIG_TIME) ? valid_config->lease_time : this_context->lease_time;
 		    
-		    if (preferred_time < 120u )
-		      preferred_time = 120u; /* sanity */
-		    if (lease_time == 0xffffffff || (preferred_time != 0xffffffff && preferred_time < lease_time))
-		      lease_time = preferred_time;
+		    if (requested_time < 120u )
+		      requested_time = 120u; /* sanity */
+		    if (lease_time == 0xffffffff || (requested_time != 0xffffffff && requested_time < lease_time))
+		      lease_time = requested_time;
 		    
 		    lease_set_expires(lease, lease_time, now);
 		    if (ia_type == OPTION6_IA_NA && hostname)
@@ -917,8 +921,9 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
 		
 		o1 =  new_opt6(OPTION6_IAADDR);
 		put_opt6(req_addr, sizeof(*req_addr));
-		put_opt6_long(lease_time);
-		put_opt6_long(lease_time);
+		/* preferred lifetime */
+		put_opt6_long(this_context && (this_context->flags & CONTEXT_DEPRECATE) ? 0 : lease_time);
+		put_opt6_long(lease_time); /* valid lifetime */
 		end_opt6(o1);
 	      }