--add-subnet option.

CHANGELOG

@@ -119,8 +119,23 @@ version 2.67
 	    6939 for this to work. It always works for directly
 	    connected clients. Thanks to Vladislav Grishenko
 	    for prompting this feature.
+	    
+	    Remove the rule for constructed DHCP ranges that the local
+	    address must be either the first or last address in the
+	    range. This was originally to avoid SLAAC addresses, but
+	    we now explicitly autoconfig and privacy addresses instead.  
 
+	    Update Polish translation. Thanks to Jan Psota.
 
+	    Fix problem in DHCPv6 vendorclass/userclass matching
+	    code. Thanks to Tanguy Bouzeloc for the patch.
+
+ 	    Update Spanish transalation. Thanks to Vicente Soriano.
+
+	    Add --add-subnet configuration, to tell upstream DNS
+	    servers where the original client is. 
+
+ 
 version 2.66
             Add the ability to act as an authoritative DNS
             server. Dnsmasq can now answer queries from the wider 'net

Makefile

@@ -114,6 +114,11 @@ merge :
 		echo -n msgmerge $(PO)/$$f && $(MSGMERGE) --no-wrap -U $(PO)/$$f $(BUILDDIR)/dnsmasq.pot; \
 	done
 
+# Cannonicalise .po file.
+%.po : 
+	@cd $(BUILDDIR) && $(MAKE) -f $(top)/Makefile dnsmasq.pot
+	mv $(PO)/$*.po $(PO)/$*.po.orig && $(MSGMERGE) --no-wrap $(PO)/$*.po.orig $(BUILDDIR)/dnsmasq.pot >$(PO)/$*.po; 
+
 $(BUILDDIR):
 	mkdir -p $(BUILDDIR)
 

contrib/mactable/macscript

@@ -0,0 +1,36 @@
+#!/bin/bash
+
+STATUS_FILE="/tmp/dnsmasq-ip-mac.status"
+
+# Script for dnsmasq lease-change hook.
+# Maintains the above file with a IP address/MAC address pairs,
+# one lease per line. Works with IPv4 and IPv6 leases, file is
+# atomically updated, so no races for users of the data.
+
+action="$1"
+mac="$2"   # IPv4
+ip="$3"
+
+# ensure it always exists.
+
+if [ ! -f "$STATUS_FILE" ]; then
+  touch "$STATUS_FILE"
+fi
+
+if [  -n "$DNSMASQ_IAID" ]; then
+    mac="$DNSMASQ_MAC"   # IPv6
+fi
+
+# worry about an add or old action when the MAC address is not known:
+# leave any old one in place in that case.
+
+if [ "$action" = "add" -o "$action" = "old" -o "$action" = "del" ]; then
+  if [ -n "$mac" -o "$action" = "del" ]; then
+    sed "/^${ip//./\.} / d" "$STATUS_FILE" > "$STATUS_FILE".new
+  
+    if [ "$action" = "add" -o "$action" = "old" ]; then
+       echo "$ip $mac" >> "$STATUS_FILE".new
+    fi
+    mv  "$STATUS_FILE".new "$STATUS_FILE" # atomic update.
+  fi
+fi

debian/rules

@@ -25,7 +25,7 @@ DEB_BUILD_ARCH_OS := $(shell dpkg-architecture -qDEB_BUILD_ARCH_OS)
 
 # Force package version based on git tags.
 ifneq (,$(filter gitversion,$(DEB_BUILD_OPTIONS)))
-     PACKAGE_VERSION = $(shell bld/get-version `pwd` |  sed 's/[a-z]/~&/;  s/-/./g; s/$$/-1/; s/^/-v/';)
+     PACKAGE_VERSION = $(shell bld/get-version `pwd` |  sed 's/test/~&/; s/[a-z]/~&/;  s/-/./g; s/$$/-1/; s/^/-v/';)
 endif
 
 ifeq (,$(filter nodbus,$(DEB_BUILD_OPTIONS)))

man/dnsmasq.8

@@ -543,7 +543,20 @@ server. The MAC address can only be added if the requestor is on the same
 subnet as the dnsmasq server. Note that the mechanism used to achieve this (an EDNS0 option)
 is not yet standardised, so this should be considered
 experimental. Also note that exposing MAC addresses in this way may
-have security and privacy implications. 
+have security and privacy implications. The warning about caching
+given for --add-subnet applies to --add-mac too.
+.TP 
+.B --add-subnet[[=<IPv4 prefix length>],<IPv6 prefix length>]
+Add the subnet address of the requestor to the DNS queries which are
+forwarded upstream. The amount of the address forwarded depends on the
+prefix length parameter: 32 (128 for IPv6) forwards the whole address,
+zero forwards none of it but still marks the request so that no
+upstream nameserver will add client address information either. The
+default is zero for both IPv4 and IPv6. Note that upstream nameservers
+may be configured to return different results based on this
+information, but the dnsmasq cache does not take account. If a dnsmasq
+instance is configured such that different results may be encountered,
+caching should be disabled.
 .TP
 .B \-c, --cache-size=<cachesize>
 Set the size of dnsmasq's cache. The default is 150 names. Setting the cache size to zero disables caching.
@@ -652,24 +665,20 @@ This forms a template which describes how to create ranges, based on the address
 
 .B --dhcp-range=::1,::400,constructor:eth0
 
-will look for addresses of the form <network>::1 or <network>:400 on
+will look for addresses on
 eth0 and then create a range from <network>::1 to <network>::400. If
 the interface is assigned more than one network, then the
 corresponding ranges will be automatically created, and then
 deprecated and finally removed again as the address is deprecated and
 then deleted. The interface name may have a final "*" wildcard. Note
-that just any address on eth0 will not do: the non-prefix part must be
-equal either the start or end address given in the dhcp-range. This is
-to prevent prefixes becoming perpetual if the interface 
-gains a SLAAC address for the prefix when it is advertised by dnsmasq.
+that just any address on eth0 will not do: it must not be an
+autoconfigured or privacy address, or be deprecated.
 
 If a dhcp-range is only being used for stateless DHCP and/or SLAAC,
 then the address can be simply ::
 
 .B --dhcp-range=::,constructor:eth0
 
-This removes the condition above, and will pick up the prefix from any address on eth0 which is NOT 
-autoconfigured, slaac, temporary or deprecated.
 
 There is a variant of the constructor: syntax using the keyword
 .B constructor-noauth.

src/config.h

@@ -39,7 +39,6 @@
 #define TFTP_MAX_CONNECTIONS 50 /* max simultaneous connections */
 #define LOG_MAX 5 /* log-queue length */
 #define RANDFILE "/dev/urandom"
-#define EDNS0_OPTION_MAC 5 /* dyndns.org temporary assignment */
 #define DNSMASQ_SERVICE "uk.org.thekelleys.dnsmasq" /* Default - may be overridden by config */
 #define DNSMASQ_PATH "/uk/org/thekelleys/dnsmasq"
 #define AUTH_TTL 600 /* default TTL for auth DNS */

src/dhcp-common.c

@@ -627,6 +627,8 @@ int lookup_dhcp_opt(int prot, char *name)
   const struct opttab_t *t;
   int i;
 
+  (void)prot;
+
 #ifdef HAVE_DHCP6
   if (prot == AF_INET6)
     t = opttab6;
@@ -646,6 +648,8 @@ int lookup_dhcp_len(int prot, int val)
   const struct opttab_t *t;
   int i;
 
+  (void)prot;
+
 #ifdef HAVE_DHCP6
   if (prot == AF_INET6)
     t = opttab6;
@@ -823,14 +827,14 @@ void log_context(int family, struct dhcp_context *context)
       template = p;
       p += sprintf(p, ", ");
       
-      if (indextoname(daemon->doing_dhcp6 ? daemon->dhcp6fd : daemon->icmp6fd, context->if_index, ifrn_name))
+      if (indextoname(daemon->icmp6fd, context->if_index, ifrn_name))
 	sprintf(p, "%s for %s", (context->flags & CONTEXT_OLD) ? "old prefix" : "constructed", ifrn_name);
     }
-  else if (context->flags & CONTEXT_TEMPLATE)
+  else if (context->flags & CONTEXT_TEMPLATE && !(context->flags & CONTEXT_RA_STATELESS))
     {
       template = p;
       p += sprintf(p, ", ");
-       
+      
       sprintf(p, "template for %s", context->template_interface);  
     }
 #endif
@@ -838,21 +842,37 @@ void log_context(int family, struct dhcp_context *context)
   if (!(context->flags & CONTEXT_OLD) &&
       ((context->flags & CONTEXT_DHCP) || family == AF_INET)) 
     {
-      inet_ntop(family, start, daemon->dhcp_buff, 256);
+#ifdef HAVE_DHCP6
+      if (context->flags & CONTEXT_RA_STATELESS)
+	{
+	  if (context->flags & CONTEXT_TEMPLATE)
+	    strncpy(daemon->dhcp_buff, context->template_interface, 256);
+	  else
+	    strcpy(daemon->dhcp_buff, daemon->addrbuff);
+	}
+      else 
+#endif
+	inet_ntop(family, start, daemon->dhcp_buff, 256);
       inet_ntop(family, end, daemon->dhcp_buff3, 256);
       my_syslog(MS_DHCP | LOG_INFO, 
-	      (context->flags & CONTEXT_RA_STATELESS) ? 
-	      _("%s stateless on %s%.0s%.0s%s") :
-	      (context->flags & CONTEXT_STATIC) ? 
-	      _("%s, static leases only on %.0s%s%s%.0s") :
-	      (context->flags & CONTEXT_PROXY) ?
-	      _("%s, proxy on subnet %.0s%s%.0s%.0s") :
-	      _("%s, IP range %s -- %s%s%.0s"),
-	      (family != AF_INET) ? "DHCPv6" : "DHCP",
+		(context->flags & CONTEXT_RA_STATELESS) ? 
+		_("%s stateless on %s%.0s%.0s%s") :
+		(context->flags & CONTEXT_STATIC) ? 
+		_("%s, static leases only on %.0s%s%s%.0s") :
+		(context->flags & CONTEXT_PROXY) ?
+		_("%s, proxy on subnet %.0s%s%.0s%.0s") :
+		_("%s, IP range %s -- %s%s%.0s"),
+		(family != AF_INET) ? "DHCPv6" : "DHCP",
 		daemon->dhcp_buff, daemon->dhcp_buff3, daemon->namebuff, template);
     }
   
 #ifdef HAVE_DHCP6
+  if (context->flags & CONTEXT_TEMPLATE)
+    {
+      strcpy(daemon->addrbuff, context->template_interface);
+      template = "";
+    }
+
   if ((context->flags & CONTEXT_RA_NAME) && !(context->flags & CONTEXT_OLD))
     my_syslog(MS_DHCP | LOG_INFO, _("DHCPv4-derived IPv6 names on %s%s"), daemon->addrbuff, template);
   

src/dhcp6.c

@@ -29,7 +29,7 @@ struct iface_param {
 
 struct mac_param {
   struct in6_addr *target;
-  unsigned char mac[DHCP_CHADDR_MAX];
+  unsigned char *mac;
   unsigned int maclen;
 };
 
@@ -99,7 +99,6 @@ void dhcp6_packet(time_t now)
   struct dhcp_context *context;
   struct dhcp_relay *relay;
   struct iface_param parm;
-  struct mac_param mac_param;
   struct cmsghdr *cmptr;
   struct msghdr msg;
   int if_index = 0;
@@ -145,8 +144,6 @@ void dhcp6_packet(time_t now)
 
   if ((port = relay_reply6(&from, sz, ifr.ifr_name)) == 0)
     {
-      int i;
-
       for (tmp = daemon->if_except; tmp; tmp = tmp->next)
 	if (tmp->name && wildcard_match(tmp->name, ifr.ifr_name))
 	  return;
@@ -182,48 +179,6 @@ void dhcp6_packet(time_t now)
       if (!iface_enumerate(AF_INET6, &parm, complete_context6))
 	return;
 
-      /* Recieving a packet from a host does not populate the neighbour
-	 cache, so we send a neighbour discovery request if we can't 
-	 find the sender. Repeat a few times in case of packet loss. */
-      
-      for (i = 0; i < 5; i++)
-	{
-	  struct timespec ts;
-	  struct neigh_packet *neigh;
-	  struct sockaddr_in6 addr;
-	  
-	  mac_param.target = &from.sin6_addr;
-	  mac_param.maclen = 0;
-	  
-	  iface_enumerate(AF_UNSPEC, &mac_param, find_mac);
-	  
-	  if (mac_param.maclen != 0)
-	    break;
-	 
-	  save_counter(0);
-	  neigh = expand(sizeof(struct neigh_packet));
-	  neigh->type = ND_NEIGHBOR_SOLICIT;
-	  neigh->code = 0;
-	  neigh->reserved = 0;
-	  neigh->target = from.sin6_addr;
-
-	  memset(&addr, 0, sizeof(addr));
-#ifdef HAVE_SOCKADDR_SA_LEN
-	  addr.sin6_len = sizeof(struct sockaddr_in6);
-#endif
-	  addr.sin6_family = AF_INET6;
-	  addr.sin6_port = htons(IPPROTO_ICMPV6);
-	  addr.sin6_addr = from.sin6_addr;
-	  addr.sin6_scope_id = from.sin6_scope_id;
-          
-	  sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(0), 0,
-		 (struct sockaddr *)&addr,  sizeof(addr));
-	  
-	  ts.tv_sec = 0;
-	  ts.tv_nsec = 100000000; /* 100ms */
-	  nanosleep(&ts, NULL);
-	}
-    
       if (daemon->if_names || daemon->if_addrs)
 	{
 	  
@@ -244,8 +199,7 @@ void dhcp6_packet(time_t now)
 	  inet_pton(AF_INET6, ALL_SERVERS, &all_servers);
 	  
 	  if (!IN6_ARE_ADDR_EQUAL(&dst_addr, &all_servers))
-	    relay_upstream6(parm.relay, sz, &from.sin6_addr, from.sin6_scope_id,
-			    mac_param.maclen == 0 ? NULL : &mac_param.mac[0], mac_param.maclen, ARPHRD_ETHER);
+	    relay_upstream6(parm.relay, sz, &from.sin6_addr, from.sin6_scope_id);
 	  return;
 	}
       
@@ -256,8 +210,7 @@ void dhcp6_packet(time_t now)
       lease_prune(NULL, now); /* lose any expired leases */
       
       port = dhcp6_reply(parm.current, if_index, ifr.ifr_name, &parm.fallback, 
-			 sz, IN6_IS_ADDR_MULTICAST(&from.sin6_addr), now,
-			 mac_param.maclen == 0 ? NULL : &mac_param.mac[0], mac_param.maclen, ARPHRD_ETHER);
+			 sz, &from.sin6_addr, now);
       
       lease_update_file(now);
       lease_update_dns(0);
@@ -276,6 +229,55 @@ void dhcp6_packet(time_t now)
     }
 }
 
+void get_client_mac(struct in6_addr *client, int iface, unsigned char *mac, unsigned int *maclenp, unsigned int *mactypep)
+{
+  /* Recieving a packet from a host does not populate the neighbour
+     cache, so we send a neighbour discovery request if we can't 
+     find the sender. Repeat a few times in case of packet loss. */
+  
+  struct neigh_packet neigh;
+  struct sockaddr_in6 addr;
+  struct mac_param mac_param;
+  int i;
+
+  neigh.type = ND_NEIGHBOR_SOLICIT;
+  neigh.code = 0;
+  neigh.reserved = 0;
+  neigh.target = *client;
+  
+  memset(&addr, 0, sizeof(addr));
+#ifdef HAVE_SOCKADDR_SA_LEN
+  addr.sin6_len = sizeof(struct sockaddr_in6);
+#endif
+  addr.sin6_family = AF_INET6;
+  addr.sin6_port = htons(IPPROTO_ICMPV6);
+  addr.sin6_addr = *client;
+  addr.sin6_scope_id = iface;
+  
+  mac_param.target = client;
+  mac_param.maclen = 0;
+  mac_param.mac = mac;
+  
+  for (i = 0; i < 5; i++)
+    {
+      struct timespec ts;
+      
+      iface_enumerate(AF_UNSPEC, &mac_param, find_mac);
+      
+      if (mac_param.maclen != 0)
+	break;
+      
+      sendto(daemon->icmp6fd, &neigh, sizeof(neigh), 0, (struct sockaddr *)&addr, sizeof(addr));
+      
+      ts.tv_sec = 0;
+      ts.tv_nsec = 100000000; /* 100ms */
+      nanosleep(&ts, NULL);
+    }
+
+  *maclenp = mac_param.maclen;
+  *mactypep = ARPHRD_ETHER;
+}
+    
 static int find_mac(int family, char *addrp, char *mac, size_t maclen, void *parmv)
 {
   struct mac_param *parm = parmv;
@@ -552,6 +554,7 @@ static int make_duid1(int index, unsigned int type, char *mac, size_t maclen, vo
   
   unsigned char *p;
   (void)index;
+  (void)parm;
 
   if (type >= 256)
     return 1;
@@ -599,7 +602,13 @@ static int construct_worker(struct in6_addr *local, int prefix,
       IN6_IS_ADDR_MULTICAST(local))
     return 1;
 
-  if (!indextoname(daemon->doing_dhcp6 ? daemon->dhcp6fd : daemon->icmp6fd, if_index, ifrn_name))
+  if (!(flags & IFACE_PERMANENT))
+    return 1;
+
+  if (flags & IFACE_DEPRECATED)
+    return 1;
+
+  if (!indextoname(daemon->icmp6fd, if_index, ifrn_name))
     return 0;
   
   for (template = daemon->dhcp6; template; template = template->next)
@@ -615,11 +624,7 @@ static int construct_worker(struct in6_addr *local, int prefix,
 	  }
 	
       }
-    else if ((addr6part(local) == addr6part(&template->start6) ||
-	      addr6part(local) == addr6part(&template->end6) ||
-	      (IN6_IS_ADDR_UNSPECIFIED(&template->start6) &&
-	       IFACE_PERMANENT == (flags & (IFACE_PERMANENT | IFACE_DEPRECATED)))) && 
-	     wildcard_match(template->template_interface, ifrn_name))
+    else if (wildcard_match(template->template_interface, ifrn_name))
       {
 	start6 = *local;
 	setaddr6part(&start6, addr6part(&template->start6));

src/dns-protocol.h

@@ -56,6 +56,10 @@
 #define T_MAILB		253	
 #define T_ANY		255
 
+#define EDNS0_OPTION_MAC            65001 /* dyndns.org temporary assignment */
+#define EDNS0_OPTION_CLIENT_SUBNET  5     /* IANA */
+
+
 struct dns_header {
   u16 id;
   u8  hb3,hb4;

src/dnsmasq.c

@@ -51,8 +51,10 @@ int main (int argc, char **argv)
   cap_user_header_t hdr = NULL;
   cap_user_data_t data = NULL;
 #endif 
+#if defined(HAVE_DHCP) || defined(HAVE_DHCP6)
   struct dhcp_context *context;
   struct dhcp_relay *relay;
+#endif
 
 #ifdef LOCALEDIR
   setlocale(LC_ALL, "");
@@ -1231,6 +1233,8 @@ void poll_resolv(int force, int do_reload, time_t now)
 
 void clear_cache_and_reload(time_t now)
 {
+  (void)now;
+
   if (daemon->port != 0)
     cache_reload();
   

src/dnsmasq.h

@@ -222,7 +222,8 @@ struct event_desc {
 #define OPT_CLEVERBIND     39
 #define OPT_TFTP           40
 #define OPT_FAST_RA        41
-#define OPT_LAST           42
+#define OPT_CLIENT_SUBNET  42
+#define OPT_LAST           43
 
 /* extra flags for my_syslog, we use a couple of facilities since they are known 
    not to occupy the same bits as priorities, no matter how syslog.h is set up. */
@@ -487,6 +488,7 @@ struct hostsfile {
 
 #define FREC_NOREBIND           1
 #define FREC_CHECKING_DISABLED  2
+#define FREC_HAS_SUBNET         4
 
 struct frec {
   union mysockaddr source;
@@ -802,6 +804,8 @@ extern struct daemon {
   struct auth_zone *auth_zones;
   struct interface_name *int_names;
   char *mxtarget;
+  int addr4_netmask;
+  int addr6_netmask;
   char *lease_file; 
   char *username, *groupname, *scriptuser;
   char *luascript;
@@ -962,6 +966,8 @@ unsigned int questions_crc(struct dns_header *header, size_t plen, char *buff);
 size_t resize_packet(struct dns_header *header, size_t plen, 
 		  unsigned char *pheader, size_t hlen);
 size_t add_mac(struct dns_header *header, size_t plen, char *limit, union mysockaddr *l3);
+size_t add_source_addr(struct dns_header *header, size_t plen, char *limit, union mysockaddr *source);
+int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer);
 int add_resource_record(struct dns_header *header, char *limit, int *truncp,
 			int nameoffset, unsigned char **pp, unsigned long ttl, 
 			int *offset, unsigned short type, unsigned short class, char *format, ...);
@@ -1212,15 +1218,15 @@ struct dhcp_config *config_find_by_address6(struct dhcp_config *configs, struct
 					    int prefix, u64 addr);
 void make_duid(time_t now);
 void dhcp_construct_contexts(time_t now);
+void get_client_mac(struct in6_addr *client, int iface, unsigned char *mac, 
+		    unsigned int *maclenp, unsigned int *mactypep);
 #endif
-
+  
 /* rfc3315.c */
 #ifdef HAVE_DHCP6
 unsigned short dhcp6_reply(struct dhcp_context *context, int interface, char *iface_name,  
-			   struct in6_addr *fallback, size_t sz, int is_multicast, time_t now,
-			   unsigned char *mac, unsigned int mac_len, unsigned int mac_type);
-void relay_upstream6(struct dhcp_relay *relay, ssize_t sz, struct in6_addr *peer_address, u32 scope_id,
-		     unsigned char *mac, unsigned int mac_len, unsigned int mac_type);
+			   struct in6_addr *fallback, size_t sz, struct in6_addr *client_addr, time_t now);
+void relay_upstream6(struct dhcp_relay *relay, ssize_t sz, struct in6_addr *peer_address, u32 scope_id);
 
 unsigned short relay_reply6( struct sockaddr_in6 *peer, ssize_t sz, char *arrival_interface);
 #endif

src/forward.c

@@ -284,6 +284,7 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 	  forward->fd = udpfd;
 	  forward->crc = crc;
 	  forward->forwardall = 0;
+	  forward->flags = 0;
 	  if (norebind)
 	    forward->flags |= FREC_NOREBIND;
 	  if (header->hb4 & HB4_CD)
@@ -331,6 +332,16 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
       if (option_bool(OPT_ADD_MAC))
 	plen = add_mac(header, plen, ((char *) header) + PACKETSZ, &forward->source);
       
+      if (option_bool(OPT_CLIENT_SUBNET))
+	{
+	  size_t new = add_source_addr(header, plen, ((char *) header) + PACKETSZ, &forward->source); 
+	  if (new != plen)
+	    {
+	      plen = new;
+	      forward->flags |= FREC_HAS_SUBNET;
+	    }
+	}
+
       while (1)
 	{ 
 	  /* only send to servers dealing with our domain.
@@ -435,8 +446,8 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
   return 0;
 }
 
-static size_t process_reply(struct dns_header *header, time_t now, 
-			    struct server *server, size_t n, int check_rebind, int checking_disabled)
+static size_t process_reply(struct dns_header *header, time_t now, struct server *server, size_t n, int check_rebind, 
+			    int checking_disabled, int check_subnet, union mysockaddr *query_source)
 {
   unsigned char *pheader, *sizep;
   char **sets = 0;
@@ -465,19 +476,29 @@ static size_t process_reply(struct dns_header *header, time_t now,
      than we allow, trim it so that we don't get overlarge
      requests for the client. We can't do this for signed packets. */
 
-  if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign)) && !is_sign)
+  if ((pheader = find_pseudoheader(header, n, &plen, &sizep, &is_sign)))
     {
-      unsigned short udpsz;
-      unsigned char *psave = sizep;
+      if (!is_sign)
+	{
+	  unsigned short udpsz;
+	  unsigned char *psave = sizep;
+	  
+	  GETSHORT(udpsz, sizep);
+	  if (udpsz > daemon->edns_pktsz)
+	    PUTSHORT(daemon->edns_pktsz, psave);
+	}
       
-      GETSHORT(udpsz, sizep);
-      if (udpsz > daemon->edns_pktsz)
-	PUTSHORT(daemon->edns_pktsz, psave);
+      if (check_subnet && !check_source(header, plen, pheader, query_source))
+	{
+	  my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch"));
+	  return 0;
+	}
     }
+      
 
   /* RFC 4035 sect 4.6 para 3 */
   if (!is_sign && !option_bool(OPT_DNSSEC))
-     header->hb4 &= ~HB4_AD;
+    header->hb4 &= ~HB4_AD;
 
   if (OPCODE(header) != QUERY || (RCODE(header) != NOERROR && RCODE(header) != NXDOMAIN))
     return n;
@@ -632,7 +653,8 @@ void reply_query(int fd, int family, time_t now)
       if (!option_bool(OPT_NO_REBIND))
 	check_rebind = 0;
       
-      if ((nn = process_reply(header, now, server, (size_t)n, check_rebind, forward->flags & FREC_CHECKING_DISABLED)))
+      if ((nn = process_reply(header, now, server, (size_t)n, check_rebind, forward->flags & FREC_CHECKING_DISABLED,
+			      forward->flags & FREC_HAS_SUBNET, &forward->source)))
 	{
 	  header->id = htons(forward->orig_id);
 	  header->hb4 |= HB4_RA; /* recursion if available */
@@ -876,7 +898,7 @@ unsigned char *tcp_request(int confd, time_t now,
 {
   size_t size = 0;
   int norebind = 0;
-  int checking_disabled;
+  int checking_disabled, check_subnet;
   size_t m;
   unsigned short qtype;
   unsigned int gotname;
@@ -906,6 +928,8 @@ unsigned char *tcp_request(int confd, time_t now,
       if (size < (int)sizeof(struct dns_header))
 	continue;
       
+      check_subnet = 0;
+
       /* save state of "cd" flag in query */
       checking_disabled = header->hb4 & HB4_CD;
        
@@ -955,7 +979,17 @@ unsigned char *tcp_request(int confd, time_t now,
 	      
 	      if (option_bool(OPT_ADD_MAC))
 		size = add_mac(header, size, ((char *) header) + 65536, &peer_addr);
-	      
+	      	
+	      if (option_bool(OPT_CLIENT_SUBNET))
+		{
+		  size_t new = add_source_addr(header, size, ((char *) header) + 65536, &peer_addr);
+		  if (size != new)
+		    {
+		      size = new;
+		      check_subnet = 1;
+		    }
+		}
+
 	      if (gotname)
 		flags = search_servers(now, &addrp, gotname, daemon->namebuff, &type, &domain, &norebind);
 	      
@@ -1056,7 +1090,8 @@ unsigned char *tcp_request(int confd, time_t now,
 			 sending replies containing questions and bogus answers. */
 		      if (crc == questions_crc(header, (unsigned int)m, daemon->namebuff))
 			m = process_reply(header, now, last_server, (unsigned int)m, 
-					  option_bool(OPT_NO_REBIND) && !norebind, checking_disabled);
+					  option_bool(OPT_NO_REBIND) && !norebind, checking_disabled,
+					  check_subnet, &peer_addr);
 		      
 		      break;
 		    }

src/helper.c

@@ -61,8 +61,13 @@ struct script_data
 #else
   time_t expires;
 #endif
-#ifdef HAVE_DHCP6
+#ifdef HAVE_TFTP
+  off_t file_len;
+#endif
+#ifdef HAVE_IPV6
   struct in6_addr addr6;
+#endif
+#ifdef HAVE_DHCP6
   int iaid, vendorclass_count;
 #endif
   unsigned char hwaddr[DHCP_CHADDR_MAX];
@@ -289,10 +294,12 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	inet_ntop(AF_INET6, &data.addr6, daemon->addrbuff, ADDRSTRLEN);
 #endif
 
+#ifdef HAVE_TFTP
       /* file length */
       if (data.action == ACTION_TFTP)
-	sprintf(daemon->dhcp_buff, "%u", data.hwaddr_len);
-      
+	sprintf(is6 ? daemon->packet : daemon->dhcp_buff, "%lu", (unsigned long)data.file_len);
+#endif
+
 #ifdef HAVE_LUASCRIPT
       if (daemon->luascript)
 	{
@@ -309,7 +316,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 		  lua_setfield(lua, -2, "destination_address");
 		  lua_pushstring(lua, hostname);
 		  lua_setfield(lua, -2, "file_name"); 
-		  lua_pushstring(lua, daemon->dhcp_buff);
+		  lua_pushstring(lua, is6 ? daemon->packet : daemon->dhcp_buff);
 		  lua_setfield(lua, -2, "file_size");
 		  lua_call(lua, 2, 0);	/* pass 2 values, expect 0 */
 		}
@@ -474,20 +481,13 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
       if (data.action != ACTION_TFTP)
 	{
 #ifdef HAVE_DHCP6
-	  if (is6)
-	    {
-	      my_setenv("DNSMASQ_IAID", daemon->dhcp_buff3, &err);
-	      my_setenv("DNSMASQ_SERVER_DUID", daemon->dhcp_packet.iov_base, &err); 
-	      if (data.hwaddr_len != 0)
-		my_setenv("DNSMASQ_MAC", daemon->dhcp_buff, &err);
-	    }
+	  my_setenv("DNSMASQ_IAID", is6 ? daemon->dhcp_buff3 : NULL, &err);
+	  my_setenv("DNSMASQ_SERVER_DUID", is6 ? daemon->dhcp_packet.iov_base : NULL, &err); 
+	  my_setenv("DNSMASQ_MAC", is6 && data.hwaddr_len != 0 ? daemon->dhcp_buff : NULL, &err);
 #endif
 	  
-	  if (!is6 && data.clid_len != 0)
-	    my_setenv("DNSMASQ_CLIENT_ID", daemon->packet, &err);
-	  
-	  if (strlen(data.interface) != 0)
-	    my_setenv("DNSMASQ_INTERFACE", data.interface, &err);
+	  my_setenv("DNSMASQ_CLIENT_ID", !is6 && data.clid_len != 0 ? daemon->packet : NULL, &err);
+	  my_setenv("DNSMASQ_INTERFACE", strlen(data.interface) != 0 ? data.interface : NULL, &err);
 	  
 #ifdef HAVE_BROKEN_RTC
 	  sprintf(daemon->dhcp_buff2, "%u", data.length);
@@ -497,8 +497,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	  my_setenv("DNSMASQ_LEASE_EXPIRES", daemon->dhcp_buff2, &err); 
 #endif
 	  
-	  if (domain)
-	    my_setenv("DNSMASQ_DOMAIN", domain, &err);
+	  my_setenv("DNSMASQ_DOMAIN", domain, &err);
 	  
 	  end = extradata + data.ed_len;
 	  buf = extradata;
@@ -536,8 +535,8 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 
 	  if (is6)
 	    buf = grab_extradata(buf, end, "DNSMASQ_RELAY_ADDRESS", &err);
-	  else if (data.giaddr.s_addr != 0)
-	    my_setenv("DNSMASQ_RELAY_ADDRESS", inet_ntoa(data.giaddr), &err); 
+	  else 
+	    my_setenv("DNSMASQ_RELAY_ADDRESS", data.giaddr.s_addr != 0 ? inet_ntoa(data.giaddr) : NULL, &err); 
 	  
 	  for (i = 0; buf; i++)
 	    {
@@ -545,22 +544,16 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	      buf = grab_extradata(buf, end, daemon->dhcp_buff2, &err);
 	    }
 	  
-	  if (data.action != ACTION_DEL && data.remaining_time != 0)
-	    {
-	      sprintf(daemon->dhcp_buff2, "%u", data.remaining_time);
-	      my_setenv("DNSMASQ_TIME_REMAINING", daemon->dhcp_buff2, &err);
-	    }
+	  sprintf(daemon->dhcp_buff2, "%u", data.remaining_time);
+	  my_setenv("DNSMASQ_TIME_REMAINING", data.action != ACTION_DEL && data.remaining_time != 0 ? daemon->dhcp_buff2 : NULL, &err);
 	  
-	  if (data.action == ACTION_OLD_HOSTNAME && hostname)
-	    {
-	      my_setenv("DNSMASQ_OLD_HOSTNAME", hostname, &err);
-	      hostname = NULL;
-	    }
+	  my_setenv("DNSMASQ_OLD_HOSTNAME", data.action == ACTION_OLD_HOSTNAME ? hostname : NULL, &err);
+	  if (data.action == ACTION_OLD_HOSTNAME)
+	    hostname = NULL;
 	}
 
-      if (option_bool(OPT_LOG_OPTS))
-	my_setenv("DNSMASQ_LOG_DHCP", "1", &err);
-	 
+      my_setenv("DNSMASQ_LOG_DHCP", option_bool(OPT_LOG_OPTS) ? "1" : NULL, &err);
+      
       /* we need to have the event_fd around if exec fails */
       if ((i = fcntl(event_fd, F_GETFD)) != -1)
 	fcntl(event_fd, F_SETFD, i | FD_CLOEXEC);
@@ -583,31 +576,44 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 
 static void my_setenv(const char *name, const char *value, int *error)
 {
-  if (*error == 0 && setenv(name, value, 1) != 0)
-    *error = errno;
+  if (*error == 0)
+    {
+      if (!value)
+	unsetenv(name);
+      else if (setenv(name, value, 1) != 0)
+	*error = errno;
+    }
 }
  
 static unsigned char *grab_extradata(unsigned char *buf, unsigned char *end,  char *env, int *err)
 {
-  unsigned char *next;
+  unsigned char *next = NULL;
+  char *val = NULL;
 
-  if (!buf || (buf == end))
-    return NULL;
-
-  for (next = buf; *next != 0; next++)
-    if (next == end)
-      return NULL;
-  
-  if (next != buf)
+  if (buf && (buf != end))
     {
-      char *p;
-      /* No "=" in value */
-      if ((p = strchr((char *)buf, '=')))
-	*p = 0;
-      my_setenv(env, (char *)buf, err);
-    }
+      for (next = buf; ; next++)
+	if (next == end)
+	  {
+	    next = NULL;
+	    break;
+	  }
+	else if (*next == 0)
+	  break;
 
-  return next + 1;
+      if (next && (next != buf))
+	{
+	  char *p;
+	  /* No "=" in value */
+	  if ((p = strchr((char *)buf, '=')))
+	    *p = 0;
+	  val = (char *)buf;
+	}
+    }
+  
+  my_setenv(env, val, err);
+   
+  return next ? next + 1 : NULL;
 }
 
 #ifdef HAVE_LUASCRIPT
@@ -739,13 +745,13 @@ void queue_tftp(off_t file_len, char *filename, union mysockaddr *peer)
 
   buf->action = ACTION_TFTP;
   buf->hostname_len = filename_len;
-  buf->hwaddr_len = file_len;
+  buf->file_len = file_len;
 
   if ((buf->flags = peer->sa.sa_family) == AF_INET)
     buf->addr = peer->in.sin_addr;
 #ifdef HAVE_IPV6
   else
-    memcpy(buf->hwaddr, &peer->in6.sin6_addr, IN6ADDRSZ);
+    buf->addr6 = peer->in6.sin6_addr;
 #endif
 
   memcpy((unsigned char *)(buf+1), filename, filename_len);

src/lease.c

@@ -788,6 +788,7 @@ void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr,
 #endif
 
   (void)force;
+  (void)now;
 
   if (hw_len != lease->hwaddr_len ||
       hw_type != lease->hwaddr_type || 
@@ -956,6 +957,8 @@ void lease_set_hostname(struct dhcp_lease *lease, char *name, int auth, char *do
 
 void lease_set_interface(struct dhcp_lease *lease, int interface, time_t now)
 {
+  (void)now;
+
   if (lease->last_interface == interface)
     return;
 
@@ -984,6 +987,8 @@ int do_script_run(time_t now)
 {
   struct dhcp_lease *lease;
 
+  (void)now;
+
 #ifdef HAVE_DBUS
   /* If we're going to be sending DBus signals, but the connection is not yet up,
      delay everything until it is. */

src/netlink.c

@@ -402,6 +402,8 @@ static int nl_async(struct nlmsghdr *h)
   	
 static void nl_newaddress(time_t now)
 {
+  (void)now;
+
   if (option_bool(OPT_CLEVERBIND) || daemon->doing_dhcp6 || daemon->relay6 || daemon->doing_ra)
     enumerate_interfaces(0);
   

src/network.c

@@ -709,6 +709,8 @@ static struct listener *create_listeners(union mysockaddr *addr, int do_tftp, in
   struct listener *l = NULL;
   int fd = -1, tcpfd = -1, tftpfd = -1;
 
+  (void)do_tftp;
+
   if (daemon->port != 0)
     {
       fd = make_sock(addr, SOCK_DGRAM, dienow);

src/option.c

@@ -134,6 +134,7 @@ struct myoption {
 #endif
 #define LOPT_FAST_RA   322
 #define LOPT_RELAY     323
+#define LOPT_ADD_SBNET 324
 
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
@@ -251,6 +252,7 @@ static const struct myoption opts[] =
     { "dhcp-generate-names", 2, 0, LOPT_GEN_NAMES },
     { "rebind-localhost-ok", 0, 0,  LOPT_LOC_REBND },
     { "add-mac", 0, 0, LOPT_ADD_MAC },
+    { "add-subnet", 2, 0, LOPT_ADD_SBNET },
     { "proxy-dnssec", 0, 0, LOPT_DNSSEC },
     { "dhcp-sequential-ip", 0, 0,  LOPT_INCR_ADDR },
     { "conntrack", 0, 0, LOPT_CONNTRACK },
@@ -397,6 +399,7 @@ static struct {
   { LOPT_PXE_SERV, ARG_DUP, "<service>", gettext_noop("Boot service for PXE menu."), NULL },
   { LOPT_TEST, 0, NULL, gettext_noop("Check configuration syntax."), NULL },
   { LOPT_ADD_MAC, OPT_ADD_MAC, NULL, gettext_noop("Add requestor's MAC address to forwarded DNS queries."), NULL },
+  { LOPT_ADD_SBNET, ARG_ONE, "<v4 pref>[,<v6 pref>]", gettext_noop("Add requestor's IP subnet to forwarded DNS queries."), NULL },
   { LOPT_DNSSEC, OPT_DNSSEC, NULL, gettext_noop("Proxy DNSSEC validation results from upstream nameservers."), NULL },
   { LOPT_INCR_ADDR, OPT_CONSEC_ADDR, NULL, gettext_noop("Attempt to allocate sequential IP addresses to DHCP clients."), NULL },
   { LOPT_CONNTRACK, OPT_CONNTRACK, NULL, gettext_noop("Copy connection-track mark from queries to upstream connections."), NULL },
@@ -1424,6 +1427,17 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	break;
       }
 
+    case LOPT_ADD_SBNET: /* --add-subnet */
+      set_option_bool(OPT_CLIENT_SUBNET);
+      if (arg)
+	{
+	  comma = split(arg);
+	  if (!atoi_check(arg, &daemon->addr4_netmask) || 
+	      (comma && !atoi_check(comma, &daemon->addr6_netmask)))
+	     ret_err(gen_err);
+	}
+      break;
+
     case '1': /* --enable-dbus */
       set_option_bool(OPT_DBUS);
       if (arg)

src/radv.c

@@ -391,10 +391,13 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
 	addr.sin6_scope_id = iface;
     }
   else
-    inet_pton(AF_INET6, ALL_NODES, &addr.sin6_addr); 
+    {
+      inet_pton(AF_INET6, ALL_NODES, &addr.sin6_addr); 
+      setsockopt(daemon->icmp6fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &iface, sizeof(iface));
+    }
   
-  send_from(daemon->icmp6fd, 0, daemon->outpacket.iov_base, save_counter(0),
-	    (union mysockaddr *)&addr, (struct all_addr *)&parm.link_local, iface); 
+  while (sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(0), 0, 
+		(struct sockaddr *)&addr, sizeof(addr)) == -1 && retry_send());
   
 }
 

src/rfc1035.c

@@ -513,15 +513,81 @@ struct macparm {
   size_t plen;
   union mysockaddr *l3;
 };
+ 
+static size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
+			       int optno, unsigned char *opt, size_t optlen)
+{ 
+  unsigned char *lenp, *datap, *p;
+  int rdlen;
+  
+  if (ntohs(header->arcount) == 0)
+    {
+      /* We are adding the pseudoheader */
+      if (!(p = skip_questions(header, plen)) ||
+	  !(p = skip_section(p, 
+			     ntohs(header->ancount) + ntohs(header->nscount), 
+			     header, plen)))
+	return plen;
+      *p++ = 0; /* empty name */
+      PUTSHORT(T_OPT, p);
+      PUTSHORT(daemon->edns_pktsz, p); /* max packet length */
+      PUTLONG(0, p);    /* extended RCODE */
+      lenp = p;
+      PUTSHORT(0, p);    /* RDLEN */
+      rdlen = 0;
+      if (((ssize_t)optlen) > (limit - (p + 4)))
+	return plen; /* Too big */
+      header->arcount = htons(1);
+      datap = p;
+    }
+  else
+    {
+      int i, is_sign;
+      unsigned short code, len;
+      
+      if (ntohs(header->arcount) != 1 ||
+	  !(p = find_pseudoheader(header, plen, NULL, NULL, &is_sign)) ||
+	  is_sign ||
+	  (!(p = skip_name(p, header, plen, 10))))
+	return plen;
+      
+      p += 8; /* skip UDP length and RCODE */
+      
+      lenp = p;
+      GETSHORT(rdlen, p);
+      if (!CHECK_LEN(header, p, plen, rdlen))
+	return plen; /* bad packet */
+      datap = p;
+
+      /* check if option already there */
+      for (i = 0; i + 4 < rdlen; i += len + 4)
+	{
+	  GETSHORT(code, p);
+	  GETSHORT(len, p);
+	  if (code == optno)
+	    return plen;
+	  p += len;
+	}
+      
+      if (((ssize_t)optlen) > (limit - (p + 4)))
+	return plen; /* Too big */
+    }
+  
+  PUTSHORT(optno, p);
+  PUTSHORT(optlen, p);
+  memcpy(p, opt, optlen);
+  p += optlen;  
+
+  PUTSHORT(p - datap, lenp);
+  return p - (unsigned char *)header;
+  
+}
 
 static int filter_mac(int family, char *addrp, char *mac, size_t maclen, void *parmv)
 {
   struct macparm *parm = parmv;
   int match = 0;
-  unsigned short rdlen;
-  struct dns_header *header = parm->header;
-  unsigned char *lenp, *datap, *p;
-  
+    
   if (family == parm->l3->sa.sa_family)
     {
       if (family == AF_INET && memcmp (&parm->l3->in.sin_addr, addrp, INADDRSZ) == 0)
@@ -535,72 +601,12 @@ static int filter_mac(int family, char *addrp, char *mac, size_t maclen, void *p
  
   if (!match)
     return 1; /* continue */
-  
-  if (ntohs(header->arcount) == 0)
-    {
-      /* We are adding the pseudoheader */
-      if (!(p = skip_questions(header, parm->plen)) ||
-	  !(p = skip_section(p, 
-			     ntohs(header->ancount) + ntohs(header->nscount), 
-			     header, parm->plen)))
-	return 0;
-      *p++ = 0; /* empty name */
-      PUTSHORT(T_OPT, p);
-      PUTSHORT(PACKETSZ, p); /* max packet length - is 512 suitable default for non-EDNS0 resolvers? */
-      PUTLONG(0, p);    /* extended RCODE */
-      lenp = p;
-      PUTSHORT(0, p);    /* RDLEN */
-      rdlen = 0;
-      if (((ssize_t)maclen) > (parm->limit - (p + 4)))
-	return 0; /* Too big */
-      header->arcount = htons(1);
-      datap = p;
-    }
-  else
-    {
-      int i, is_sign;
-      unsigned short code, len;
-      
-      if (ntohs(header->arcount) != 1 ||
-	  !(p = find_pseudoheader(header, parm->plen, NULL, NULL, &is_sign)) ||
-	  is_sign ||
-	  (!(p = skip_name(p, header, parm->plen, 10))))
-	return 0;
-      
-      p += 8; /* skip UDP length and RCODE */
-      
-      lenp = p;
-      GETSHORT(rdlen, p);
-      if (!CHECK_LEN(header, p, parm->plen, rdlen))
-	return 0; /* bad packet */
-      datap = p;
 
-      /* check if option already there */
-      for (i = 0; i + 4 < rdlen; i += len + 4)
-	{
-	  GETSHORT(code, p);
-	  GETSHORT(len, p);
-	  if (code == EDNS0_OPTION_MAC)
-	    return 0;
-	  p += len;
-	}
-      
-      if (((ssize_t)maclen) > (parm->limit - (p + 4)))
-	return 0; /* Too big */
-    }
-  
-  PUTSHORT(EDNS0_OPTION_MAC, p);
-  PUTSHORT(maclen, p);
-  memcpy(p, mac, maclen);
-  p += maclen;  
-
-  PUTSHORT(p - datap, lenp);
-  parm->plen = p - (unsigned char *)header;
+  parm->plen = add_pseudoheader(parm->header, parm->plen, parm->limit,  EDNS0_OPTION_MAC, (unsigned char *)mac, maclen);
   
   return 0; /* done */
 }	      
      
-
 size_t add_mac(struct dns_header *header, size_t plen, char *limit, union mysockaddr *l3)
 {
   struct macparm parm;
@@ -621,7 +627,102 @@ size_t add_mac(struct dns_header *header, size_t plen, char *limit, union mysock
   return parm.plen; 
 }
 
-    
+struct subnet_opt {
+  u16 family;
+  u8 source_netmask, scope_netmask;
+#ifdef HAVE_IPV6 
+  u8 addr[IN6ADDRSZ];
+#else
+  u8 addr[INADDRSZ];
+#endif
+};
+
+size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
+{
+  /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
+  
+  int len;
+  void *addrp;
+
+  if (source->sa.sa_family == AF_INET)
+    {
+      opt->family = htons(1);
+      opt->source_netmask = daemon->addr4_netmask;
+      addrp = &source->in.sin_addr;
+    }
+#ifdef HAVE_IPV6
+  else
+    {
+      opt->family = htons(2);
+      opt->source_netmask = daemon->addr6_netmask;
+      addrp = &source->in6.sin6_addr;
+    }
+#endif
+  
+  opt->scope_netmask = 0;
+  len = 0;
+  
+  if (opt->source_netmask != 0)
+    {
+      len = ((opt->source_netmask - 1) >> 3) + 1;
+      memcpy(opt->addr, addrp, len);
+      if (opt->source_netmask & 7)
+	opt->addr[len-1] &= 0xff << (8 - (opt->source_netmask & 7));
+    }
+
+  return len + 4;
+}
+ 
+size_t add_source_addr(struct dns_header *header, size_t plen, char *limit, union mysockaddr *source)
+{
+  /* http://tools.ietf.org/html/draft-vandergaast-edns-client-subnet-02 */
+  
+  int len;
+  struct subnet_opt opt;
+  
+  len = calc_subnet_opt(&opt, source);
+  return add_pseudoheader(header, plen, (unsigned char *)limit, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len);
+}
+  
+int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer)
+{
+  /* Section 9.2, Check that subnet option in reply matches. */
+
+
+ int len, calc_len;
+  struct subnet_opt opt;
+  unsigned char *p;
+  int code, i, rdlen;
+  
+   calc_len = calc_subnet_opt(&opt, peer);
+   
+   if (!(p = skip_name(pseudoheader, header, plen, 10)))
+     return 1;
+   
+   p += 8; /* skip UDP length and RCODE */
+   
+   GETSHORT(rdlen, p);
+   if (!CHECK_LEN(header, p, plen, rdlen))
+     return 1; /* bad packet */
+   
+   /* check if option there */
+   for (i = 0; i + 4 < rdlen; i += len + 4)
+     {
+       GETSHORT(code, p);
+       GETSHORT(len, p);
+       if (code == EDNS0_OPTION_CLIENT_SUBNET)
+	 {
+	   /* make sure this doesn't mismatch. */
+	   opt.scope_netmask = p[3];
+	   if (len != calc_len || memcmp(p, &opt, len) != 0)
+	     return 0;
+	 }
+       p += len;
+     }
+   
+   return 1;
+}
+
 /* is addr in the non-globally-routed IP space? */ 
 static int private_net(struct in_addr addr, int ban_localhost) 
 {