Fix problem with IPv6 in new ARP-search code.

Thanks to Luis Carvalho for spotting the error.

CHANGELOG

@@ -31,7 +31,41 @@ version 2.76
 	    Return REFUSED when running out of forwarding table slots,
 	    not SERVFAIL.
 
-	
+            Add --max-port configuration. Thanks to Hans Dedecker for
+	    the patch.
+
+	    Add --script-arp and two new functions for the dhcp-script.
+	    These are "arp" and "arp-old" which announce the arrival and
+	    removal of entries in the ARP or nieghbour tables.
+
+	    Extend --add-mac to allow a new encoding of the MAC address 
+	    as base64, by configurting --add-mac=base64
+ 
+	    Add --add-cpe-id option.
+
+            Don't crash with divide-by-zero if an IPv6 dhcp-range
+	    is declared as a whole /64.
+	    (ie xx::0 to xx::ffff:ffff:ffff:ffff) 
+	    Thanks to Laurent Bendel for spotting this problem.
+
+	    Add support for a TTL parameter in --host-record and
+	    --cname.
+
+	    Add --dhcp-ttl option.
+
+	    Add --tftp-mtu option. Thanks to Patrick McLean for the 
+	    initial patch.
+
+	    Check return-code of inet_pton() when parsing dhcp-option.
+	    Bad addresses could fail to generate errors and result in
+	    garbage dhcp-options being sent. Thanks to Marc Branchaud 
+	    for spotting this.
+
+	    Fix wrong value for EDNS UDP packet size when using 
+	    --servers-file to define upstream DNS servers. Thanks to
+	    Scott Bonar for the bug report.
+
+
 version 2.75
             Fix reversion on 2.74 which caused 100% CPU use when a 
 	    dhcp-script is configured. Thanks to Adrian Davey for

man/dnsmasq.8

@@ -60,7 +60,7 @@ in the same way as for DHCP-derived names. Note that this does not
 apply to domain names in cnames, PTR records, TXT records etc.
 .TP
 .B \-T, --local-ttl=<time>
-When replying with information from /etc/hosts or the DHCP leases
+When replying with information from /etc/hosts or configuration or the DHCP leases
 file dnsmasq by default sets the time-to-live field to zero, meaning
 that the requester should not itself cache the information. This is
 the correct thing to do in almost all situations. This option allows a
@@ -68,6 +68,9 @@ time-to-live (in seconds) to be given for these replies. This will
 reduce the load on the server at the expense of clients using stale
 data under some circumstances.
 .TP
+.B --dhcp-ttl=<time>
+As for --local-ttl, but affects only replies with information from DHCP leases. If both are given, --dhcp-ttl applies for DHCP information, and --local-ttl for others. Setting this to zero eliminates the effect of --local-ttl for DHCP.
+.TP
 .B --neg-ttl=<time>
 Negative replies from upstream servers normally contain time-to-live
 information in SOA records which dnsmasq uses for caching. If the
@@ -174,6 +177,13 @@ queries. Dnsmasq picks random ports as source for outbound queries:
 when this option is given, the ports used will always to larger
 than that specified. Useful for systems behind firewalls. 
 .TP
+.B --max-port=<port>
+Use ports lower than that given as source for outbound DNS queries.
+Dnsmasq picks random ports as source for outbound queries:
+when this option is given, the ports used will always be lower
+than that specified. Useful for systems behind firewalls.
+.TP
+
 .B \-i, --interface=<interface name>
 Listen only on the specified interface(s). Dnsmasq automatically adds
 the loopback (local) interface to the list of interfaces to use when
@@ -522,7 +532,7 @@ zone files: the port, weight and priority numbers are in a different
 order. More than one SRV record for a given service/domain is allowed,
 all that match are returned.
 .TP
-.B --host-record=<name>[,<name>....],[<IPv4-address>],[<IPv6-address>]
+.B --host-record=<name>[,<name>....],[<IPv4-address>],[<IPv6-address>][,<TTL>]
 Add A, AAAA and PTR records to the DNS. This adds one or more names to
 the DNS with associated IPv4 (A) and IPv6 (AAAA) records. A name may
 appear in more than one 
@@ -539,6 +549,10 @@ is in effect. Short and long names may appear in the same
 .B host-record,
 eg. 
 .B --host-record=laptop,laptop.thekelleys.org,192.168.0.1,1234::100
+
+If the time-to-live is given, it overrides the default, which is zero
+or the value of --local-ttl. The value is a positive integer and gives 
+the time-to-live in seconds.
 .TP
 .B \-Y, --txt-record=<name>[[,<text>],<text>]
 Return a TXT DNS record. The value of TXT record is a set of strings,
@@ -552,7 +566,7 @@ Return a PTR DNS record.
 .B --naptr-record=<name>,<order>,<preference>,<flags>,<service>,<regexp>[,<replacement>]
 Return an NAPTR DNS record, as specified in RFC3403.
 .TP
-.B --cname=<cname>,<target>
+.B --cname=<cname>,<target>[,<TTL>]
 Return a CNAME record which indicates that <cname> is really
 <target>. There are significant limitations on the target; it must be a
 DNS name which is known to dnsmasq from /etc/hosts (or additional
@@ -561,6 +575,10 @@ hosts files), from DHCP, from --interface-name or from another
 If the target does not satisfy this
 criteria, the whole cname is ignored. The cname must be unique, but it
 is permissable to have more than one cname pointing to the same target.
+
+If the time-to-live is given, it overrides the default, which is zero
+or the value of -local-ttl. The value is a positive integer and gives 
+the time-to-live in seconds.
 .TP
 .B --dns-rr=<name>,<RR-number>,[<hex data>]
 Return an arbitrary DNS Resource Record. The number is the type of the
@@ -597,7 +615,7 @@ configured a zero is added in front of the label. ::1 becomes 0--1.
 The address range can be of the form
 <ip address>,<ip address> or <ip address>/<netmask>
 .TP
-.B --add-mac
+.B --add-mac[=base64|text]
 Add the MAC address of the requestor to DNS queries which are
 forwarded upstream. This may be used to DNS filtering by the upstream
 server. The MAC address can only be added if the requestor is on the same
@@ -605,7 +623,12 @@ subnet as the dnsmasq server. Note that the mechanism used to achieve this (an E
 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. The warning about caching
-given for --add-subnet applies to --add-mac too.
+given for --add-subnet applies to --add-mac too. An alternative encoding of the 
+MAC, as base64, is enabled by adding the "base64" parameter and a human-readable encoding of hex-and-colons is enabled by added the "text" parameter.
+.TP
+.B --add-cpe-id=<string>
+Add a arbitrary identifying string to o DNS queries which are
+forwarded upstream.
 .TP 
 .B --add-subnet[[=[<IPv4 address>/]<IPv4 prefix length>][,[<IPv6 address>/]<IPv6 prefix length>]]
 Add a subnet address to the DNS queries which are forwarded
@@ -760,7 +783,7 @@ 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=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-addr>[,<end-addr>][,<mode>][,<netmask>[,<broadcast>]][,<lease time>]
+.B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-addr>[,<end-addr>|<mode>][,<netmask>[,<broadcast>]][,<lease time>]
 .TP
 .B \-F, --dhcp-range=[tag:<tag>[,tag:<tag>],][set:<tag>,]<start-IPv6addr>[,<end-IPv6addr>|constructor:<interface>][,<mode>][,<prefix-len>][,<lease time>]
 
@@ -1536,11 +1559,11 @@ At dnsmasq startup, the script will be invoked for
 all existing leases as they are read from the lease file. Expired
 leases will be called with "del" and others with "old". When dnsmasq
 receives a HUP signal, the script will be invoked for existing leases
-with an "old " event.
+with an "old" event.
 
 
-There are two further actions which may appear as the first argument
-to the script, "init" and "tftp". More may be added in the future, so
+There are four further actions which may appear as the first argument
+to the script, "init", "arp-add", "arp-del" and "tftp". More may be added in the future, so
 scripts should be written to ignore unknown actions. "init" is
 described below in 
 .B --leasefile-ro
@@ -1548,6 +1571,11 @@ The "tftp" action is invoked when a TFTP file transfer completes: the
 arguments are the file size in bytes, the address to which the file
 was sent, and the complete pathname of the file.
  
+The "arp-add" and "arp-del" actions are only called if enabled with
+.B --script-arp
+They are are supplied with a MAC address and IP address as arguments. "arp-add" indicates
+the arrival of a new entry in the ARP or neighbour table, and "arp-del" indicates the deletion of same.
+
 .TP
 .B --dhcp-luascript=<path>
 Specify a script written in Lua, to be run when leases are created,
@@ -1594,10 +1622,24 @@ table holds the tags
 .B file_name
 and 
 .B file_size.
+
+The 
+.B arp
+and
+.B arp-old
+functions are called only when enabled with
+.B --script-arp
+and have a table which holds the tags
+.B mac_addres
+and
+.B client_address.
 .TP
 .B --dhcp-scriptuser
 Specify the user as which to run the lease-change script or Lua script. This defaults to root, but can be changed to another user using this flag. 
-.TP 
+.TP
+.B --script-arp
+Enable the "arp" and "arp-old" functions in the dhcp-script and dhcp-luascript.
+.TP
 .B \-9, --leasefile-ro
 Completely suppress use of the lease database file. The file will not
 be created, read, or written. Change the way the lease-change
@@ -1768,6 +1810,10 @@ require about (2*n) + 10 descriptors. If
 .B --tftp-port-range
 is given, that can affect the number of concurrent connections.
 .TP
+.B --tftp-mtu=<mtu size>
+Use size as the ceiling of the MTU supported by the intervening network when 
+negotiating TFTP blocksize, overriding the MTU setting of the local interface  if it is larger.
+.TP
 .B --tftp-no-blocksize
 Stop the TFTP server from negotiating the "blocksize" option with a
 client. Some buggy clients request this option but then behave badly

src/arp.c

@@ -44,6 +44,11 @@ static int filter_mac(int family, char *addrp, char *mac, size_t maclen, void *p
   if (maclen > DHCP_CHADDR_MAX)
     return 1;
 
+#ifndef HAVE_IPV6
+  if (family != AF_INET)
+    return 1;
+#endif
+
   /* Look for existing entry */
   for (arp = arps; arp; arp = arp->next)
     {
@@ -117,30 +122,36 @@ int find_mac(union mysockaddr *addr, unsigned char *mac, int lazy, time_t now)
   
   /* If the database is less then INTERVAL old, look in there */
   if (difftime(now, last) < INTERVAL)
-    for (arp = arps; arp; arp = arp->next)
-      {
-	if (addr->sa.sa_family == arp->family)
-	  {
-	    if (arp->addr.addr.addr4.s_addr != addr->in.sin_addr.s_addr)
-	      continue;
-	  }
+    {
+      /* addr == NULL -> just make cache up-to-date */
+      if (!addr)
+	return 0;
+
+      for (arp = arps; arp; arp = arp->next)
+	{
+	  if (addr->sa.sa_family != arp->family)
+	    continue;
+	    
+	  if (arp->family == AF_INET &&
+	      arp->addr.addr.addr4.s_addr != addr->in.sin_addr.s_addr)
+	    continue;
+	    
 #ifdef HAVE_IPV6
-	else
-	  {
-	    if (!IN6_ARE_ADDR_EQUAL(&arp->addr.addr.addr6, &addr->in6.sin6_addr))
-	      continue;
-	  }
+	  if (arp->family == AF_INET6 && 
+	      !IN6_ARE_ADDR_EQUAL(&arp->addr.addr.addr6, &addr->in6.sin6_addr))
+	    continue;
 #endif
-	
-	/* Only accept positive entries unless in lazy mode. */
-	if (arp->status != ARP_EMPTY || lazy || updated)
-	  {
-	    if (mac && arp->hwlen != 0)
-	      memcpy(mac, arp->hwaddr, arp->hwlen);
-	    return arp->hwlen;
-	  }
-      }
-  
+	  
+	  /* Only accept positive entries unless in lazy mode. */
+	  if (arp->status != ARP_EMPTY || lazy || updated)
+	    {
+	      if (mac && arp->hwlen != 0)
+		memcpy(mac, arp->hwaddr, arp->hwlen);
+	      return arp->hwlen;
+	    }
+	}
+    }
+
   /* Not found, try the kernel */
   if (!updated)
      {
@@ -209,8 +220,8 @@ int do_arp_script_run(void)
   if (old)
     {
 #ifdef HAVE_SCRIPT
-      if (option_bool(OPT_DNS_CLIENT))
-	queue_arp(ACTION_ARP_OLD, old->hwaddr, old->hwlen, old->family, &old->addr);
+      if (option_bool(OPT_SCRIPT_ARP))
+	queue_arp(ACTION_ARP_DEL, old->hwaddr, old->hwlen, old->family, &old->addr);
 #endif
       arp = old;
       old = arp->next;
@@ -223,7 +234,7 @@ int do_arp_script_run(void)
     if (arp->status == ARP_NEW)
       {
 #ifdef HAVE_SCRIPT
-	if (option_bool(OPT_DNS_CLIENT))
+	if (option_bool(OPT_SCRIPT_ARP))
 	  queue_arp(ACTION_ARP, arp->hwaddr, arp->hwlen, arp->family, &arp->addr);
 #endif
 	arp->status = ARP_FOUND;

src/auth.c

@@ -824,7 +824,7 @@ size_t answer_auth(struct dns_header *header, char *limit, size_t qlen, time_t n
 
   /* Advertise our packet size limit in our reply */
   if (have_pseudoheader)
-    return add_pseudoheader(header,  ansp - (unsigned char *)header, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit);
+    return add_pseudoheader(header,  ansp - (unsigned char *)header, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0);
 
   return ansp - (unsigned char *)header;
 }

src/bpf.c

@@ -20,7 +20,9 @@
 #include <ifaddrs.h>
 
 #include <sys/param.h>
+#if defined(HAVE_BSD_NETWORK) && !defined(__APPLE__)
 #include <sys/sysctl.h>
+#endif
 #include <net/if.h>
 #include <net/route.h>
 #include <net/if_dl.h>

src/cache.c

@@ -778,6 +778,7 @@ static void add_hosts_cname(struct crec *target)
 	(crec = whine_malloc(sizeof(struct crec))))
       {
 	crec->flags = F_FORWARD | F_IMMORTAL | F_NAMEP | F_CONFIG | F_CNAME;
+	crec->ttd = a->ttl;
 	crec->name.namep = a->alias;
 	crec->addr.cname.target.cache = target;
 	crec->addr.cname.uid = target->uid;
@@ -981,6 +982,7 @@ int read_hostsfile(char *filename, unsigned int index, int cache_size, struct cr
 		  strcat(cache->name.sname, ".");
 		  strcat(cache->name.sname, domain_suffix);
 		  cache->flags = flags;
+		  cache->ttd = daemon->local_ttl;
 		  add_hosts_entry(cache, &addr, addrlen, index, rhash, hashsz);
 		  name_count++;
 		}
@@ -988,6 +990,7 @@ int read_hostsfile(char *filename, unsigned int index, int cache_size, struct cr
 		{
 		  strcpy(cache->name.sname, canon);
 		  cache->flags = flags;
+		  cache->ttd = daemon->local_ttl;
 		  add_hosts_entry(cache, &addr, addrlen, index, rhash, hashsz);
 		  name_count++;
 		}
@@ -1057,6 +1060,7 @@ void cache_reload(void)
 	  ((cache = whine_malloc(sizeof(struct crec)))))
 	{
 	  cache->flags = F_FORWARD | F_NAMEP | F_CNAME | F_IMMORTAL | F_CONFIG;
+	  cache->ttd = a->ttl;
 	  cache->name.namep = a->alias;
 	  cache->addr.cname.target.int_name = intr;
 	  cache->addr.cname.uid = SRC_INTERFACE;
@@ -1071,6 +1075,7 @@ void cache_reload(void)
 	(cache->addr.ds.keydata = blockdata_alloc(ds->digest, ds->digestlen)))
       {
 	cache->flags = F_FORWARD | F_IMMORTAL | F_DS | F_CONFIG | F_NAMEP;
+	cache->ttd = daemon->local_ttl;
 	cache->name.namep = ds->name;
 	cache->addr.ds.keylen = ds->digestlen;
 	cache->addr.ds.algo = ds->algo;
@@ -1095,6 +1100,7 @@ void cache_reload(void)
 	    (cache = whine_malloc(sizeof(struct crec))))
 	  {
 	    cache->name.namep = nl->name;
+	    cache->ttd = hr->ttl;
 	    cache->flags = F_HOSTS | F_IMMORTAL | F_FORWARD | F_REVERSE | F_IPV4 | F_NAMEP | F_CONFIG;
 	    add_hosts_entry(cache, (struct all_addr *)&hr->addr, INADDRSZ, SRC_CONFIG, (struct crec **)daemon->packet, revhashsz);
 	  }
@@ -1103,6 +1109,7 @@ void cache_reload(void)
 	    (cache = whine_malloc(sizeof(struct crec))))
 	  {
 	    cache->name.namep = nl->name;
+	    cache->ttd = hr->ttl;
 	    cache->flags = F_HOSTS | F_IMMORTAL | F_FORWARD | F_REVERSE | F_IPV6 | F_NAMEP | F_CONFIG;
 	    add_hosts_entry(cache, (struct all_addr *)&hr->addr6, IN6ADDRSZ, SRC_CONFIG, (struct crec **)daemon->packet, revhashsz);
 	  }

src/dhcp.c

@@ -651,7 +651,7 @@ int address_allocate(struct dhcp_context *context,
   /* hash hwaddr: use the SDBM hashing algorithm.  Seems to give good
      dispersal even with similarly-valued "strings". */ 
   for (j = 0, i = 0; i < hw_len; i++)
-    j += hwaddr[i] + (j << 6) + (j << 16) - j;
+    j = hwaddr[i] + (j << 6) + (j << 16) - j;
   
   for (pass = 0; pass <= 1; pass++)
     for (c = context; c; c = c->current)

src/dhcp6.c

@@ -420,7 +420,7 @@ struct dhcp_context *address6_allocate(struct dhcp_context *context,  unsigned c
     j = rand64();
   else
     for (j = iaid, i = 0; i < clid_len; i++)
-      j += clid[i] + (j << 6) + (j << 16) - j;
+      j = clid[i] + (j << 6) + (j << 16) - j;
   
   for (pass = 0; pass <= plain_range ? 1 : 0; pass++)
     for (c = context; c; c = c->current)
@@ -434,7 +434,16 @@ struct dhcp_context *address6_allocate(struct dhcp_context *context,  unsigned c
 	    /* seed is largest extant lease addr in this context */
 	    start = lease_find_max_addr6(c) + serial;
 	  else
-	    start = addr6part(&c->start6) + ((j + c->addr_epoch) % (1 + addr6part(&c->end6) - addr6part(&c->start6)));
+	    {
+	      u64 range = 1 + addr6part(&c->end6) - addr6part(&c->start6);
+	      u64 offset = j + c->addr_epoch;
+
+	      /* don't divide by zero if range is whole 2^64 */
+	      if (range != 0)
+		offset = offset % range;
+
+	      start = addr6part(&c->start6) + offset;
+	    }
 
 	  /* iterate until we find a free address. */
 	  addr = start;

src/dns-protocol.h

@@ -16,6 +16,7 @@
 
 #define NAMESERVER_PORT 53
 #define TFTP_PORT       69
+#define MAX_PORT        65535u
 
 #define IN6ADDRSZ       16
 #define INADDRSZ        4

src/dnsmasq.c

@@ -219,7 +219,13 @@ int main (int argc, char **argv)
   if (option_bool(OPT_LOOP_DETECT))
     die(_("loop detection not available: set HAVE_LOOP in src/config.h"), NULL, EC_BADCONF);
 #endif
-  
+
+  if (daemon->max_port != MAX_PORT && daemon->min_port == 0)
+    daemon->min_port = 1024u;
+
+  if (daemon->max_port < daemon->min_port)
+    die(_("max_port cannot be smaller than min_port"), NULL, EC_BADCONF);
+
   now = dnsmasq_time();
 
   /* Create a serial at startup if not configured. */
@@ -254,10 +260,10 @@ int main (int argc, char **argv)
      creating any file descriptors which shouldn't be leaked
      to the lease-script init process. We need to call common_init
      before lease_init to allocate buffers it uses.
-     The script subsystrm relies on DHCP buffers, hence the last two
+     The script subsystem relies on DHCP buffers, hence the last two
      conditions below. */  
   if (daemon->dhcp || daemon->doing_dhcp6 || daemon->relay4 || 
-      daemon->relay6 || option_bool(OPT_TFTP) || option_bool(OPT_DNS_CLIENT))
+      daemon->relay6 || option_bool(OPT_TFTP) || option_bool(OPT_SCRIPT_ARP))
     {
       dhcp_common_init();
       if (daemon->dhcp || daemon->doing_dhcp6)
@@ -555,16 +561,19 @@ int main (int argc, char **argv)
      {       
        /* open  stdout etc to /dev/null */
        int nullfd = open("/dev/null", O_RDWR);
-       dup2(nullfd, STDOUT_FILENO);
-       dup2(nullfd, STDERR_FILENO);
-       dup2(nullfd, STDIN_FILENO);
-       close(nullfd);
+       if (nullfd != -1)
+	 {
+	   dup2(nullfd, STDOUT_FILENO);
+	   dup2(nullfd, STDERR_FILENO);
+	   dup2(nullfd, STDIN_FILENO);
+	   close(nullfd);
+	 }
      }
    
    /* if we are to run scripts, we need to fork a helper before dropping root. */
   daemon->helperfd = -1;
 #ifdef HAVE_SCRIPT 
-  if ((daemon->dhcp || daemon->dhcp6 || option_bool(OPT_TFTP) || option_bool(OPT_DNS_CLIENT)) && 
+  if ((daemon->dhcp || daemon->dhcp6 || option_bool(OPT_TFTP) || option_bool(OPT_SCRIPT_ARP)) && 
       (daemon->lease_change_command || daemon->luascript))
       daemon->helperfd = create_helper(pipewrite, err_pipe[1], script_uid, script_gid, max_fd);
 #endif
@@ -931,6 +940,9 @@ int main (int argc, char **argv)
       while (helper_buf_empty() && do_script_run(now)); 
 #    endif
 
+      /* Refresh cache */
+      if (option_bool(OPT_SCRIPT_ARP))
+	find_mac(NULL, NULL, 0, now);
       while (helper_buf_empty() && do_arp_script_run());
 
 #    ifdef HAVE_TFTP

src/dnsmasq.h

@@ -235,8 +235,10 @@ struct event_desc {
 #define OPT_LOOP_DETECT    50
 #define OPT_EXTRALOG       51
 #define OPT_TFTP_NO_FAIL   52
-#define OPT_DNS_CLIENT     53
-#define OPT_LAST           54
+#define OPT_SCRIPT_ARP     53
+#define OPT_MAC_B64        54
+#define OPT_MAC_HEX        55
+#define OPT_LAST           56
 
 /* 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. */
@@ -306,6 +308,7 @@ struct ptr_record {
 };
 
 struct cname {
+  int ttl;
   char *alias, *target;
   struct cname *next;
 }; 
@@ -342,6 +345,7 @@ struct auth_zone {
 
 
 struct host_record {
+  int ttl;
   struct name_list {
     char *name;
     struct name_list *next;
@@ -636,7 +640,7 @@ struct frec {
 #define ACTION_ADD           4
 #define ACTION_TFTP          5
 #define ACTION_ARP           6
-#define ACTION_ARP_OLD       7
+#define ACTION_ARP_DEL       7
 
 #define LEASE_NEW            1  /* newly created */
 #define LEASE_CHANGED        2  /* modified */
@@ -950,8 +954,8 @@ extern struct daemon {
   char *log_file; /* optional log file */
   int max_logs;  /* queue limit */
   int cachesize, ftabsize;
-  int port, query_port, min_port;
-  unsigned long local_ttl, neg_ttl, max_ttl, min_cache_ttl, max_cache_ttl, auth_ttl;
+  int port, query_port, min_port, max_port;
+  unsigned long local_ttl, neg_ttl, max_ttl, min_cache_ttl, max_cache_ttl, auth_ttl, dhcp_ttl, use_dhcp_ttl;
   char *dns_client_id;
   struct hostsfile *addn_hosts;
   struct dhcp_context *dhcp, *dhcp6;
@@ -971,7 +975,7 @@ extern struct daemon {
   struct dhcp_netid_list *dhcp_ignore, *dhcp_ignore_names, *dhcp_gen_names; 
   struct dhcp_netid_list *force_broadcast, *bootp_dynamic;
   struct hostsfile *dhcp_hosts_file, *dhcp_opts_file, *dynamic_dirs;
-  int dhcp_max, tftp_max;
+  int dhcp_max, tftp_max, tftp_mtu;
   int dhcp_server_port, dhcp_client_port;
   int start_tftp_port, end_tftp_port; 
   unsigned int min_leasetime;
@@ -1519,7 +1523,7 @@ int expand_workspace(unsigned char ***wkspc, int *szp, int new);
 unsigned char *find_pseudoheader(struct dns_header *header, size_t plen,
 				   size_t *len, unsigned char **p, int *is_sign, int *is_last);
 size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
-			unsigned short udp_sz, int optno, unsigned char *opt, size_t optlen, int set_do);
+			unsigned short udp_sz, int optno, unsigned char *opt, size_t optlen, int set_do, int replace);
 size_t add_do_bit(struct dns_header *header, size_t plen, unsigned char *limit);
 size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *limit, 
 			union mysockaddr *source, time_t now, int *check_subnet);

src/dnssec.c

@@ -1697,7 +1697,15 @@ static int prove_non_existence_nsec3(struct dns_header *header, size_t plen, uns
     return 0;
 
   p++; /* flags */
+
   GETSHORT (iterations, p);
+  /* Upper-bound iterations, to avoid DoS.
+     Strictly, there are lower bounds for small keys, but
+     since we don't have key size info here, at least limit
+     to the largest bound, for 4096-bit keys. RFC 5155 10.3 */
+  if (iterations > 2500)
+    return 0;
+  
   salt_len = *p++;
   salt = p;
   if (!CHECK_LEN(header, salt, plen, salt_len))
@@ -1783,7 +1791,7 @@ static int prove_non_existence_nsec3(struct dns_header *header, size_t plen, uns
     }
   while ((closest_encloser = strchr(closest_encloser, '.')));
   
-  if (!closest_encloser)
+  if (!closest_encloser || !next_closest)
     return 0;
   
   /* Look for NSEC3 that proves the non-existence of the next-closest encloser */

src/edns0.c

@@ -95,8 +95,10 @@ unsigned char *find_pseudoheader(struct dns_header *header, size_t plen, size_t
   return ret;
 }
  
+
+/* replace == 2 ->delete existing option only. */
 size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
-			unsigned short udp_sz, int optno, unsigned char *opt, size_t optlen, int set_do)
+			unsigned short udp_sz, int optno, unsigned char *opt, size_t optlen, int set_do, int replace)
 { 
   unsigned char *lenp, *datap, *p, *udp_len, *buff = NULL;
   int rdlen = 0, is_sign, is_last;
@@ -120,7 +122,7 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
 
       if (set_do)
 	{
-	  p -=2;
+	  p -= 2;
 	  flags |= 0x8000;
 	  PUTSHORT(flags, p);
 	}
@@ -136,13 +138,36 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
 	return plen;
       	  
       /* check if option already there */
-      for (i = 0; i + 4 < rdlen; i += len + 4)
+      for (i = 0; i + 4 < rdlen;)
 	{
 	  GETSHORT(code, p);
 	  GETSHORT(len, p);
+	  
+	  /* malformed option, delete the whole OPT RR and start again. */
+	  if (i + len > rdlen)
+	    {
+	      rdlen = 0;
+	      is_last = 0;
+	      break;
+	    }
+	  
 	  if (code == optno)
-	    return plen;
-	  p += len;
+	    {
+	      if (replace == 0)
+		return plen;
+
+	      /* delete option if we're to replace it. */
+	      p -= 4;
+	      rdlen -= len + 4;
+	      memcpy(p, p+len+4, rdlen - i);
+	      PUTSHORT(rdlen, lenp);
+	      lenp -= 2;
+	    }
+	  else
+	    {
+	      p += len;
+	      i += len + 4;
+	    }
 	}
 
       /* If we're going to extend the RR, it has to be the last RR in the packet */
@@ -190,7 +215,7 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
     return plen; /* Too big */
   
   /* Add new option */
-  if (optno != 0)
+  if (optno != 0 && replace != 2)
     {
       PUTSHORT(optno, p);
       PUTSHORT(optlen, p);
@@ -203,7 +228,7 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
 
 size_t add_do_bit(struct dns_header *header, size_t plen, unsigned char *limit)
 {
-  return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, 0, NULL, 0, 1);
+  return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, 0, NULL, 0, 1, 0);
 }
 
 static unsigned char char64(unsigned char c)
@@ -221,23 +246,25 @@ static void encoder(unsigned char *in, char *out)
 
 static size_t add_dns_client(struct dns_header *header, size_t plen, unsigned char *limit, union mysockaddr *l3, time_t now)
 {
-  int maclen;
+  int maclen, replace = 2; /* can't get mac address, just delete any incoming. */
   unsigned char mac[DHCP_CHADDR_MAX];
-  char encode[8]; /* handle 6 byte MACs */
+  char encode[18]; /* handle 6 byte MACs */
 
   if ((maclen = find_mac(l3, mac, 1, now)) == 6)
     {
-      encoder(mac, encode);
-      encoder(mac+3, encode+4);
-      
-      plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMDEVICEID, (unsigned char *)encode, 8, 0); 
+      replace = 1;
+
+      if (option_bool(OPT_MAC_HEX))
+	print_mac(encode, mac, maclen);
+      else
+	{
+	  encoder(mac, encode);
+	  encoder(mac+3, encode+4);
+	  encode[8] = 0;
+	}
     }
 
-  if (daemon->dns_client_id)
-    plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMCPEID, 
-			    (unsigned char *)daemon->dns_client_id, strlen(daemon->dns_client_id), 0);
-
-  return plen; 
+  return add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMDEVICEID, (unsigned char *)encode, strlen(encode), 0, replace); 
 }
 
 
@@ -247,7 +274,7 @@ static size_t add_mac(struct dns_header *header, size_t plen, unsigned char *lim
   unsigned char mac[DHCP_CHADDR_MAX];
 
   if ((maclen = find_mac(l3, mac, 1, now)) != 0)
-    plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0); 
+    plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_MAC, mac, maclen, 0, 0); 
     
   return plen; 
 }
@@ -280,8 +307,11 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
   void *addrp;
   int sa_family = source->sa.sa_family;
 
+  opt->source_netmask = 0;
+  opt->scope_netmask = 0;
+
 #ifdef HAVE_IPV6
-  if (source->sa.sa_family == AF_INET6)
+  if (source->sa.sa_family == AF_INET6 && daemon->add_subnet6)
     {
       opt->source_netmask = daemon->add_subnet6->mask;
       if (daemon->add_subnet6->addr_used) 
@@ -292,8 +322,9 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
       else 
 	addrp = &source->in6.sin6_addr;
     }
-  else
 #endif
+
+  if (source->sa.sa_family == AF_INET && daemon->add_subnet4)
     {
       opt->source_netmask = daemon->add_subnet4->mask;
       if (daemon->add_subnet4->addr_used)
@@ -301,26 +332,26 @@ static size_t calc_subnet_opt(struct subnet_opt *opt, union mysockaddr *source)
 	  sa_family = daemon->add_subnet4->addr.sa.sa_family;
 	  addrp = get_addrp(&daemon->add_subnet4->addr, sa_family);
 	} 
-      else 
-	addrp = &source->in.sin_addr;
+	else 
+	  addrp = &source->in.sin_addr;
     }
   
-  opt->scope_netmask = 0;
+#ifdef HAVE_IPV6
+  opt->family = htons(sa_family == AF_INET6 ? 2 : 1);
+#else
+  opt->family = htons(1);
+#endif
+  
   len = 0;
   
   if (opt->source_netmask != 0)
     {
-#ifdef HAVE_IPV6
-      opt->family = htons(sa_family == AF_INET6 ? 2 : 1);
-#else
-      opt->family = htons(1);
-#endif
       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;
 }
  
@@ -332,7 +363,7 @@ static size_t add_source_addr(struct dns_header *header, size_t plen, unsigned c
   struct subnet_opt opt;
   
   len = calc_subnet_opt(&opt, source);
-  return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0);
+  return add_pseudoheader(header, plen, (unsigned char *)limit, PACKETSZ, EDNS0_OPTION_CLIENT_SUBNET, (unsigned char *)&opt, len, 0, 0);
 }
 
 int check_source(struct dns_header *header, size_t plen, unsigned char *pseudoheader, union mysockaddr *peer)
@@ -381,8 +412,12 @@ size_t add_edns0_config(struct dns_header *header, size_t plen, unsigned char *l
   if (option_bool(OPT_ADD_MAC))
     plen  = add_mac(header, plen, limit, source, now);
   
-  if (option_bool(OPT_DNS_CLIENT))
+  if (option_bool(OPT_MAC_B64) || option_bool(OPT_MAC_HEX))
     plen = add_dns_client(header, plen, limit, source, now);
+
+  if (daemon->dns_client_id)
+    plen = add_pseudoheader(header, plen, limit, PACKETSZ, EDNS0_OPTION_NOMCPEID, 
+			    (unsigned char *)daemon->dns_client_id, strlen(daemon->dns_client_id), 0, 1);
   
   if (option_bool(OPT_CLIENT_SUBNET))
     {

src/forward.c

@@ -853,7 +853,7 @@ void reply_query(int fd, int family, time_t now)
      we get a good reply from another server. Kill it when we've
      had replies from all to avoid filling the forwarding table when
      everything is broken */
-  if (forward->forwardall == 0 || --forward->forwardall == 1 || RCODE(header) != SERVFAIL)
+  if (forward->forwardall == 0 || --forward->forwardall == 1 || RCODE(header) != REFUSED)
     {
       int check_rebind = 0, no_cache_dnssec = 0, cache_secure = 0, bogusanswer = 0;
 

src/helper.c

@@ -221,12 +221,12 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	}
       else if (data.action == ACTION_ARP)
 	{
-	  action_str = "arp";
+	  action_str = "arp-add";
 	  is6 = (data.flags != AF_INET);
 	}
-       else if (data.action == ACTION_ARP_OLD)
+       else if (data.action == ACTION_ARP_DEL)
 	{
-	  action_str = "arp-old";
+	  action_str = "arp-del";
 	  is6 = (data.flags != AF_INET);
 	  data.action = ACTION_ARP;
 	}
@@ -300,7 +300,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
     
       if (!is6)
 	inet_ntop(AF_INET, &data.addr, daemon->addrbuff, ADDRSTRLEN);
-#ifdef HAVE_DHCP6
+#ifdef HAVE_IPV6
       else
 	inet_ntop(AF_INET6, &data.addr6, daemon->addrbuff, ADDRSTRLEN);
 #endif

src/inotify.c

@@ -54,7 +54,10 @@ static char *my_readlink(char *path)
 	{
 	  /* Not link or doesn't exist. */
 	  if (errno == EINVAL || errno == ENOENT)
-	    return NULL;
+	    {
+	      free(buf);
+	      return NULL;
+	    }
 	  else
 	    die(_("cannot access path %s: %s"), path, EC_MISC);
 	}
@@ -200,6 +203,8 @@ void set_dynamic_inotify(int flag, int total_size, struct crec **rhash, int revh
 	       free(path);
 	     }
 	 }
+
+       closedir(dir_stream);
     }
 }
 

src/lease.c

@@ -1110,18 +1110,22 @@ int do_script_run(time_t now)
 }
 
 #ifdef HAVE_SCRIPT
+/* delim == -1 -> delim = 0, but embeded 0s, creating extra records, are OK. */
 void lease_add_extradata(struct dhcp_lease *lease, unsigned char *data, unsigned int len, int delim)
 {
   unsigned int i;
   
-  /* check for embeded NULLs */
-  for (i = 0; i < len; i++)
-    if (data[i] == 0)
-      {
-	len = i;
-	break;
-      }
-
+  if (delim == -1)
+    delim = 0;
+  else
+    /* check for embeded NULLs */
+    for (i = 0; i < len; i++)
+      if (data[i] == 0)
+	{
+	  len = i;
+	  break;
+	}
+  
   if ((lease->extradata_size - lease->extradata_len) < (len + 1))
     {
       size_t newsz = lease->extradata_len + len + 100;

src/network.c

@@ -532,13 +532,14 @@ static int iface_allowed_v4(struct in_addr local, int if_index, char *label,
 {
   union mysockaddr addr;
   int prefix, bit;
+ 
+  (void)broadcast; /* warning */
 
   memset(&addr, 0, sizeof(addr));
 #ifdef HAVE_SOCKADDR_SA_LEN
   addr.in.sin_len = sizeof(addr.in);
 #endif
   addr.in.sin_family = AF_INET;
-  addr.in.sin_addr = broadcast; /* warning */
   addr.in.sin_addr = local;
   addr.in.sin_port = htons(daemon->port);
 
@@ -809,10 +810,11 @@ int tcp_interface(int fd, int af)
   int opt = 1;
   struct cmsghdr *cmptr;
   struct msghdr msg;
+  socklen_t len;
   
-  /* use mshdr do that the CMSDG_* macros are available */
+  /* use mshdr so that the CMSDG_* macros are available */
   msg.msg_control = daemon->packet;
-  msg.msg_controllen = daemon->packet_buff_sz;
+  msg.msg_controllen = len = daemon->packet_buff_sz;
   
   /* we overwrote the buffer... */
   daemon->srv_save = NULL;
@@ -820,18 +822,21 @@ int tcp_interface(int fd, int af)
   if (af == AF_INET)
     {
       if (setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &opt, sizeof(opt)) != -1 &&
-	  getsockopt(fd, IPPROTO_IP, IP_PKTOPTIONS, msg.msg_control, (socklen_t *)&msg.msg_controllen) != -1)
-	for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
-	  if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO)
-            {
-              union {
-                unsigned char *c;
-                struct in_pktinfo *p;
-              } p;
-	      
-	      p.c = CMSG_DATA(cmptr);
-	      if_index = p.p->ipi_ifindex;
-	    }
+	  getsockopt(fd, IPPROTO_IP, IP_PKTOPTIONS, msg.msg_control, &len) != -1)
+	{
+	  msg.msg_controllen = len;
+	  for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
+	    if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_PKTINFO)
+	      {
+		union {
+		  unsigned char *c;
+		  struct in_pktinfo *p;
+		} p;
+		
+		p.c = CMSG_DATA(cmptr);
+		if_index = p.p->ipi_ifindex;
+	      }
+	}
     }
 #ifdef HAVE_IPV6
   else
@@ -849,9 +854,10 @@ int tcp_interface(int fd, int af)
 #endif
 
       if (set_ipv6pktinfo(fd) &&
-	  getsockopt(fd, IPPROTO_IPV6, PKTOPTIONS, msg.msg_control, (socklen_t *)&msg.msg_controllen) != -1)
+	  getsockopt(fd, IPPROTO_IPV6, PKTOPTIONS, msg.msg_control, &len) != -1)
 	{
-          for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
+          msg.msg_controllen = len;
+	  for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
             if (cmptr->cmsg_level == IPPROTO_IPV6 && cmptr->cmsg_type == daemon->v6pktinfo)
               {
                 union {
@@ -1119,7 +1125,7 @@ int random_sock(int family)
   if ((fd = socket(family, SOCK_DGRAM, 0)) != -1)
     {
       union mysockaddr addr;
-      unsigned int ports_avail = 65536u - (unsigned short)daemon->min_port;
+      unsigned int ports_avail = ((unsigned short)daemon->max_port - (unsigned short)daemon->min_port) + 1;
       int tries = ports_avail < 30 ? 3 * ports_avail : 100;
 
       memset(&addr, 0, sizeof(addr));
@@ -1132,8 +1138,8 @@ int random_sock(int family)
 	  {
 	    unsigned short port = rand16();
 	    
-	    if (daemon->min_port != 0)
-	      port = htons(daemon->min_port + (port % ((unsigned short)ports_avail)));
+            if (daemon->min_port != 0 || daemon->max_port != MAX_PORT)
+              port = htons(daemon->min_port + (port % ((unsigned short)ports_avail)));
 	    
 	    if (family == AF_INET) 
 	      {
@@ -1403,7 +1409,6 @@ void add_update_server(int flags,
       serv->domain = domain_str;
       serv->next = next;
       serv->queries = serv->failed_queries = 0;
-      serv->edns_pktsz = daemon->edns_pktsz;
 #ifdef HAVE_LOOP
       serv->uid = rand32();
 #endif      
@@ -1441,6 +1446,10 @@ void check_servers(void)
     {
       if (!(serv->flags & (SERV_LITERAL_ADDRESS | SERV_NO_ADDR | SERV_USE_RESOLV | SERV_NO_REBIND)))
 	{
+	  /* Init edns_pktsz for newly created server records. */
+	  if (serv->edns_pktsz == 0)
+	    serv->edns_pktsz = daemon->edns_pktsz;
+	  
 #ifdef HAVE_DNSSEC
 	  if (option_bool(OPT_DNSSEC_VALID))
 	    { 

src/option.c

@@ -154,8 +154,12 @@ struct myoption {
 #define LOPT_HOST_INOTIFY  342
 #define LOPT_DNSSEC_STAMP  343
 #define LOPT_TFTP_NO_FAIL  344
-#define LOPT_DNS_CLIENT_ID 355
-
+#define LOPT_MAXPORT       345
+#define LOPT_CPE_ID        346
+#define LOPT_SCRIPT_ARP    347
+#define LOPT_DHCPTTL       348
+#define LOPT_TFTP_MTU      349
+ 
 #ifdef HAVE_GETOPT_LONG
 static const struct option opts[] =  
 #else
@@ -241,6 +245,7 @@ static const struct myoption opts[] =
     { "tftp-unique-root", 0, 0, LOPT_APREF },
     { "tftp-root", 1, 0, LOPT_PREFIX },
     { "tftp-max", 1, 0, LOPT_TFTP_MAX },
+    { "tftp-mtu", 1, 0, LOPT_TFTP_MTU },
     { "tftp-lowercase", 0, 0, LOPT_TFTP_LC },
     { "ptr-record", 1, 0, LOPT_PTR },
     { "naptr-record", 1, 0, LOPT_NAPTR },
@@ -271,6 +276,7 @@ static const struct myoption opts[] =
     { "dhcp-alternate-port", 2, 0, LOPT_ALTPORT },
     { "dhcp-scriptuser", 1, 0, LOPT_SCRIPTUSR },
     { "min-port", 1, 0, LOPT_MINPORT },
+    { "max-port", 1, 0, LOPT_MAXPORT },
     { "dhcp-fqdn", 0, 0, LOPT_DHCP_FQDN },
     { "cname", 1, 0, LOPT_CNAME },
     { "pxe-prompt", 1, 0, LOPT_PXE_PROMT },
@@ -280,9 +286,9 @@ static const struct myoption opts[] =
     { "dhcp-proxy", 2, 0, LOPT_PROXY },
     { "dhcp-generate-names", 2, 0, LOPT_GEN_NAMES },
     { "rebind-localhost-ok", 0, 0,  LOPT_LOC_REBND },
-    { "add-mac", 0, 0, LOPT_ADD_MAC },
+    { "add-mac", 2, 0, LOPT_ADD_MAC },
     { "add-subnet", 2, 0, LOPT_ADD_SBNET },
-    { "add-dns-client", 2, 0 , LOPT_DNS_CLIENT_ID },
+    { "add-cpe-id", 1, 0 , LOPT_CPE_ID },
     { "proxy-dnssec", 0, 0, LOPT_DNSSEC },
     { "dhcp-sequential-ip", 0, 0,  LOPT_INCR_ADDR },
     { "conntrack", 0, 0, LOPT_CONNTRACK },
@@ -315,6 +321,8 @@ static const struct myoption opts[] =
     { "quiet-dhcp6", 0, 0, LOPT_QUIET_DHCP6 },
     { "quiet-ra", 0, 0, LOPT_QUIET_RA },
     { "dns-loop-detect", 0, 0, LOPT_LOOP_DETECT },
+    { "script-arp", 0, 0, LOPT_SCRIPT_ARP },
+    { "dhcp-ttl", 1, 0 , LOPT_DHCPTTL },
     { NULL, 0, 0, 0 }
   };
 
@@ -412,6 +420,7 @@ static struct {
   { '6', ARG_ONE, "<path>", gettext_noop("Shell script to run on DHCP lease creation and destruction."), NULL },
   { LOPT_LUASCRIPT, ARG_DUP, "path", gettext_noop("Lua script to run on DHCP lease creation and destruction."), NULL },
   { LOPT_SCRIPTUSR, ARG_ONE, "<username>", gettext_noop("Run lease-change scripts as this user."), NULL },
+  { LOPT_SCRIPT_ARP, OPT_SCRIPT_ARP, NULL, gettext_noop("Call dhcp-script with changes to local ARP table."), NULL },
   { '7', ARG_DUP, "<path>", gettext_noop("Read configuration from all the files in this directory."), NULL },
   { '8', ARG_ONE, "<facilty>|<file>", gettext_noop("Log to this syslog facility or file. (defaults to DAEMON)"), NULL },
   { '9', OPT_LEASE_RO, NULL, gettext_noop("Do not use leasefile."), NULL },
@@ -425,6 +434,7 @@ static struct {
   { LOPT_SECURE, OPT_TFTP_SECURE, NULL, gettext_noop("Allow access only to files owned by the user running dnsmasq."), NULL },
   { LOPT_TFTP_NO_FAIL, OPT_TFTP_NO_FAIL, NULL, gettext_noop("Do not terminate the service if TFTP directories are inaccessible."), NULL },
   { LOPT_TFTP_MAX, ARG_ONE, "<integer>", gettext_noop("Maximum number of conncurrent TFTP transfers (defaults to %s)."), "#" },
+  { LOPT_TFTP_MTU, ARG_ONE, "<integer>", gettext_noop("Maximum MTU to use for TFTP transfers."), NULL },
   { LOPT_NOBLOCK, OPT_TFTP_NOBLOCK, NULL, gettext_noop("Disable the TFTP blocksize extension."), NULL },
   { LOPT_TFTP_LC, OPT_TFTP_LC, NULL, gettext_noop("Convert TFTP filenames to lowercase"), NULL },
   { LOPT_TFTPPORTS, ARG_ONE, "<start>,<end>", gettext_noop("Ephemeral port range for use by TFTP transfers."), NULL },
@@ -438,24 +448,25 @@ static struct {
   { LOPT_ALTPORT, ARG_ONE, "[=<ports>]", gettext_noop("Use alternative ports for DHCP."), NULL },
   { LOPT_NAPTR, ARG_DUP, "<name>,<naptr>", gettext_noop("Specify NAPTR DNS record."), NULL },
   { LOPT_MINPORT, ARG_ONE, "<port>", gettext_noop("Specify lowest port available for DNS query transmission."), NULL },
+  { LOPT_MAXPORT, ARG_ONE, "<port>", gettext_noop("Specify highest port available for DNS query transmission."), NULL },
   { LOPT_DHCP_FQDN, OPT_DHCP_FQDN, NULL, gettext_noop("Use only fully qualified domain names for DHCP clients."), NULL },
   { LOPT_GEN_NAMES, ARG_DUP, "[=tag:<tag>]", gettext_noop("Generate hostnames based on MAC address for nameless clients."), NULL},
   { LOPT_PROXY, ARG_DUP, "[=<ipaddr>]...", gettext_noop("Use these DHCP relays as full proxies."), NULL },
   { LOPT_RELAY, ARG_DUP, "<local-addr>,<server>[,<interface>]", gettext_noop("Relay DHCP requests to a remote server"), NULL},
-  { LOPT_CNAME, ARG_DUP, "<alias>,<target>", gettext_noop("Specify alias name for LOCAL DNS name."), NULL },
+  { LOPT_CNAME, ARG_DUP, "<alias>,<target>[,<ttl>]", gettext_noop("Specify alias name for LOCAL DNS name."), NULL },
   { LOPT_PXE_PROMT, ARG_DUP, "<prompt>,[<timeout>]", gettext_noop("Prompt to send to PXE clients."), NULL },
   { 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_MAC, ARG_DUP, "[=base64|text]", gettext_noop("Add requestor's MAC address to forwarded DNS queries."), NULL },
   { LOPT_ADD_SBNET, ARG_ONE, "<v4 pref>[,<v6 pref>]", gettext_noop("Add specified IP subnet to forwarded DNS queries."), NULL },
-  { LOPT_DNS_CLIENT_ID, ARG_ONE, "<proxyname>", gettext_noop("Add client identification to forwarded DNS queries."), NULL },
+  { LOPT_CPE_ID, ARG_ONE, "<text>", gettext_noop("Add client identification to forwarded DNS queries."), NULL },
   { LOPT_DNSSEC, OPT_DNSSEC_PROXY, 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 },
   { LOPT_FQDN, OPT_FQDN_UPDATE, NULL, gettext_noop("Allow DHCP clients to do their own DDNS updates."), NULL },
   { LOPT_RA, OPT_RA, NULL, gettext_noop("Send router-advertisements for interfaces doing DHCPv6"), NULL },
   { LOPT_DUID, ARG_ONE, "<enterprise>,<duid>", gettext_noop("Specify DUID_EN-type DHCPv6 server DUID"), NULL },
-  { LOPT_HOST_REC, ARG_DUP, "<name>,<address>", gettext_noop("Specify host (A/AAAA and PTR) records"), NULL },
+  { LOPT_HOST_REC, ARG_DUP, "<name>,<address>[,<ttl>]", gettext_noop("Specify host (A/AAAA and PTR) records"), NULL },
   { LOPT_RR, ARG_DUP, "<name>,<RR-number>,[<data>]", gettext_noop("Specify arbitrary DNS resource record"), NULL },
   { LOPT_CLVERBIND, OPT_CLEVERBIND, NULL, gettext_noop("Bind to interfaces in use - check for new interfaces"), NULL },
   { LOPT_AUTHSERV, ARG_ONE, "<NS>,<interface>", gettext_noop("Export local names to global DNS"), NULL },
@@ -479,9 +490,10 @@ static struct {
   { LOPT_QUIET_DHCP, OPT_QUIET_DHCP, NULL, gettext_noop("Do not log routine DHCP."), NULL },
   { LOPT_QUIET_DHCP6, OPT_QUIET_DHCP6, NULL, gettext_noop("Do not log routine DHCPv6."), NULL },
   { LOPT_QUIET_RA, OPT_QUIET_RA, NULL, gettext_noop("Do not log RA."), NULL },
-  { LOPT_LOCAL_SERVICE, OPT_LOCAL_SERVICE, NULL, gettext_noop("Accept queries only from directly-connected networks"), NULL },
-  { LOPT_LOOP_DETECT, OPT_LOOP_DETECT, NULL, gettext_noop("Detect and remove DNS forwarding loops"), NULL },
+  { LOPT_LOCAL_SERVICE, OPT_LOCAL_SERVICE, NULL, gettext_noop("Accept queries only from directly-connected networks."), NULL },
+  { LOPT_LOOP_DETECT, OPT_LOOP_DETECT, NULL, gettext_noop("Detect and remove DNS forwarding loops."), NULL },
   { LOPT_IGNORE_ADDR, ARG_DUP, "<ipaddr>", gettext_noop("Ignore DNS responses containing ipaddr."), NULL }, 
+  { LOPT_DHCPTTL, ARG_ONE, "<ttl>", gettext_noop("Set TTL in DNS responses with DHCP-derived addresses."), NULL }, 
   { 0, 0, NULL, NULL, NULL }
 }; 
 
@@ -1187,7 +1199,8 @@ static int parse_dhcp_opt(char *errstr, char *arg, int flags)
 	      cp = comma;
 	      comma = split(cp);
 	      slash = split_chr(cp, '/');
-	      inet_pton(AF_INET, cp, &in);
+	      if (!inet_pton(AF_INET, cp, &in))
+		ret_err(_("bad IPv4 address"));
 	      if (!slash)
 		{
 		  memcpy(op, &in, INADDRSZ);
@@ -1635,12 +1648,12 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    
           daemon->add_subnet4 = new;
 
-          new = opt_malloc(sizeof(struct mysubnet));
           if (comma)
             {
-              if ((end = split_chr(comma, '/')))
-                {
-                  /* has subnet+len */
+	      new = opt_malloc(sizeof(struct mysubnet));
+	      if ((end = split_chr(comma, '/')))
+		{
+		  /* has subnet+len */
                   err = parse_mysockaddr(comma, &new->addr);
                   if (err)
                     ret_err(err);
@@ -1653,8 +1666,9 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
                   if (!atoi_check(comma, &new->mask))
                     ret_err(gen_err);
                 }
-            }
-          daemon->add_subnet6 = new;
+          
+	      daemon->add_subnet6 = new;
+	    }
 	}
       break;
 
@@ -1977,11 +1991,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		  comma = split(arg); 
 		  daemon->soa_retry = (u32)atoi(arg);
 		  if (comma)
-		    {
-		      arg = comma;
-		      comma = split(arg); 
-		      daemon->soa_expiry = (u32)atoi(arg);
-		    }
+		    daemon->soa_expiry = (u32)atoi(comma);
 		}
 	    }
 	}
@@ -2153,12 +2163,26 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	}
       break;
       
-    case LOPT_DNS_CLIENT_ID: /* --add-dns-client */
-       set_option_bool(OPT_DNS_CLIENT);
-       if (arg)
+    case LOPT_CPE_ID: /* --add-dns-client */
+      if (arg)
 	daemon->dns_client_id = opt_string_alloc(arg);
       break;
 
+    case LOPT_ADD_MAC: /* --add-mac */
+      if (!arg)
+	set_option_bool(OPT_ADD_MAC);
+      else
+	{
+	  unhide_metas(arg);
+	  if (strcmp(arg, "base64") == 0)
+	    set_option_bool(OPT_MAC_B64);
+	  else if (strcmp(arg, "text") == 0)
+	    set_option_bool(OPT_MAC_HEX);
+	  else
+	    ret_err(gen_err);
+	}
+      break;
+
     case 'u':  /* --user */
       daemon->username = opt_string_alloc(arg);
       break;
@@ -2512,6 +2536,11 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	ret_err(gen_err);
       break;
 
+    case LOPT_MAXPORT:  /* --max-port */
+      if (!atoi_check16(arg, &daemon->max_port))
+	ret_err(gen_err);
+      break;
+
     case '0':  /* --dns-forward-max */
       if (!atoi_check(arg, &daemon->ftabsize))
 	ret_err(gen_err);
@@ -2555,6 +2584,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
     case LOPT_MINCTTL: /* --min-cache-ttl */
     case LOPT_MAXCTTL: /* --max-cache-ttl */
     case LOPT_AUTHTTL: /* --auth-ttl */
+    case LOPT_DHCPTTL: /* --dhcp-ttl */
       {
 	int ttl;
 	if (!atoi_check(arg, &ttl))
@@ -2573,6 +2603,11 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	  daemon->max_cache_ttl = (unsigned long)ttl;
 	else if (option == LOPT_AUTHTTL)
 	  daemon->auth_ttl = (unsigned long)ttl;
+	else if (option == LOPT_DHCPTTL)
+	  {
+	    daemon->dhcp_ttl = (unsigned long)ttl;
+	    daemon->use_dhcp_ttl = 1;
+	  }
 	else
 	  daemon->local_ttl = (unsigned long)ttl;
 	break;
@@ -2591,6 +2626,11 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	ret_err(gen_err);
       break;  
 
+    case LOPT_TFTP_MTU:  /*  --tftp-mtu */
+      if (!atoi_check(arg, &daemon->tftp_mtu))
+	ret_err(gen_err);
+      break;
+
     case LOPT_PREFIX: /* --tftp-prefix */
       comma = split(arg);
       if (comma)
@@ -2733,13 +2773,14 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		leasepos = 3;
 		if (!is_same_net(new->start, new->end, new->netmask))
 		  ret_err(_("inconsistent DHCP range"));
-	      }
+		
 	    
-	    if (k >= 4 && strchr(a[3], '.') &&  
-		(inet_pton(AF_INET, a[3], &new->broadcast) > 0))
-	      {
-		new->flags |= CONTEXT_BRDCAST;
-		leasepos = 4;
+		if (k >= 4 && strchr(a[3], '.') &&  
+		    (inet_pton(AF_INET, a[3], &new->broadcast) > 0))
+		  {
+		    new->flags |= CONTEXT_BRDCAST;
+		    leasepos = 4;
+		  }
 	      }
 	  }
 #ifdef HAVE_DHCP6
@@ -2829,6 +2870,9 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	
 	if (leasepos < k)
 	  {
+	    if (leasepos != k-1)
+	      ret_err(_("bad dhcp-range"));
+	    
 	    if (strcmp(a[leasepos], "infinite") == 0)
 	      new->lease_time = 0xffffffff;
 	    else if (strcmp(a[leasepos], "deprecated") == 0)
@@ -2923,7 +2967,6 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 			}
 
 		      if (len == -1)
-
 			ret_err(_("bad hex constant"));
 		      else if ((new->clid = opt_malloc(len)))
 			{
@@ -3616,8 +3659,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    (!(inet_pton(AF_INET, a[1], &new->out) > 0)))
 	  option = '?';
 	
-	if (k == 3)
-	  inet_pton(AF_INET, a[2], &new->mask);
+	if (k == 3 && !inet_pton(AF_INET, a[2], &new->mask))
+	  option = '?';
 	
 	if (dash && 
 	    (!(inet_pton(AF_INET, dash, &new->end) > 0) ||
@@ -3667,12 +3710,15 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
     case LOPT_CNAME: /* --cname */
       {
 	struct cname *new;
-	char *alias;
-	char *target;
+	char *alias, *target, *ttls;
+	int ttl = -1;
 
 	if (!(comma = split(arg)))
 	  ret_err(gen_err);
 	
+	if ((ttls = split(comma)) && !atoi_check(ttls, &ttl))
+	  ret_err(_("bad TTL"));
+	
 	alias = canonicalise_opt(arg);
 	target = canonicalise_opt(comma);
 	    
@@ -3688,6 +3734,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 	    daemon->cnames = new;
 	    new->alias = alias;
 	    new->target = target;
+	    new->ttl = ttl;
 	  }
       
 	break;
@@ -3753,7 +3800,7 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
     case LOPT_RR: /* dns-rr */
       {
        	struct txt_record *new;
-	size_t len = len;
+	size_t len = 0;
 	char *data;
 	int val;
 
@@ -3861,13 +3908,8 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
 		    if (!atoi_check16(arg, &priority))
 		      ret_err(_("invalid priority"));
 			
-		    if (comma)
-		      {
-			arg = comma;
-			comma = split(arg);
-			if (!atoi_check16(arg, &weight))
-			  ret_err(_("invalid weight"));
-		      }
+		    if (comma && !atoi_check16(comma, &weight))
+		      ret_err(_("invalid weight"));
 		  }
 	      }
 	  }
@@ -3888,14 +3930,22 @@ static int one_opt(int option, char *arg, char *errstr, char *gen_err, int comma
       {
 	struct host_record *new = opt_malloc(sizeof(struct host_record));
 	memset(new, 0, sizeof(struct host_record));
-	
+	new->ttl = -1;
+
 	if (!arg || !(comma = split(arg)))
 	  ret_err(_("Bad host-record"));
 	
 	while (arg)
 	  {
 	    struct all_addr addr;
-	    if (inet_pton(AF_INET, arg, &addr))
+	    char *dig;
+
+	    for (dig = arg; *dig != 0; dig++)
+	      if (*dig < '0' || *dig > '9')
+		break;
+	    if (*dig == 0)
+	      new->ttl = atoi(arg);
+	    else if (inet_pton(AF_INET, arg, &addr))
 	      new->addr = addr.addr.addr4;
 #ifdef HAVE_IPV6
 	    else if (inet_pton(AF_INET6, arg, &addr))
@@ -4462,6 +4512,7 @@ void read_opts(int argc, char **argv, char *compile_opts)
   daemon->soa_refresh = SOA_REFRESH;
   daemon->soa_retry = SOA_RETRY;
   daemon->soa_expiry = SOA_EXPIRY;
+  daemon->max_port = MAX_PORT;
 
   add_txt("version.bind", "dnsmasq-" VERSION, 0 );
   add_txt("authors.bind", "Simon Kelley", 0);
@@ -4561,21 +4612,35 @@ void read_opts(int argc, char **argv, char *compile_opts)
     {
       struct server *tmp;
       for (tmp = daemon->servers; tmp; tmp = tmp->next)
-	{
-	  tmp->edns_pktsz = daemon->edns_pktsz;
-	 
-	  if (!(tmp->flags & SERV_HAS_SOURCE))
-	    {
-	      if (tmp->source_addr.sa.sa_family == AF_INET)
-		tmp->source_addr.in.sin_port = htons(daemon->query_port);
+	if (!(tmp->flags & SERV_HAS_SOURCE))
+	  {
+	    if (tmp->source_addr.sa.sa_family == AF_INET)
+	      tmp->source_addr.in.sin_port = htons(daemon->query_port);
 #ifdef HAVE_IPV6
-	      else if (tmp->source_addr.sa.sa_family == AF_INET6)
-		tmp->source_addr.in6.sin6_port = htons(daemon->query_port);
+	    else if (tmp->source_addr.sa.sa_family == AF_INET6)
+	      tmp->source_addr.in6.sin6_port = htons(daemon->query_port);
 #endif 
-	    }
-	} 
-    }
+	  }
+    } 
   
+  if (daemon->host_records)
+    {
+      struct host_record *hr;
+      
+      for (hr = daemon->host_records; hr; hr = hr->next)
+	if (hr->ttl == -1)
+	  hr->ttl = daemon->local_ttl;
+    }
+
+  if (daemon->cnames)
+    {
+      struct cname *cn;
+      
+      for (cn = daemon->cnames; cn; cn = cn->next)
+	if (cn->ttl == -1)
+	  cn->ttl = daemon->local_ttl;
+    }
+
   if (daemon->if_addrs)
     {  
       struct iname *tmp;

src/radv.c

@@ -28,11 +28,12 @@
 
 struct ra_param {
   time_t now;
-  int ind, managed, other, found_context, first, adv_router;
+  int ind, managed, other, first, adv_router;
   char *if_name;
   struct dhcp_netid *tags;
   struct in6_addr link_local, link_global, ula;
   unsigned int glob_pref_time, link_pref_time, ula_pref_time, adv_interval, prio;
+  struct dhcp_context *found_context;
 };
 
 struct search_param {
@@ -251,7 +252,7 @@ static void send_ra_alias(time_t now, int iface, char *iface_name, struct in6_ad
   parm.ind = iface;
   parm.managed = 0;
   parm.other = 0;
-  parm.found_context = 0;
+  parm.found_context = NULL;
   parm.adv_router = 0;
   parm.if_name = iface_name;
   parm.first = 1;
@@ -308,8 +309,14 @@ static void send_ra_alias(time_t now, int iface, char *iface_name, struct in6_ad
 	  unsigned int old = difftime(now, context->address_lost_time);
 	  
 	  if (old > context->saved_valid)
-	    {
+	    { 
 	      /* We've advertised this enough, time to go */
+	     
+	      /* If this context held the timeout, and there's another context in use
+		 transfer the timeout there. */
+	      if (context->ra_time != 0 && parm.found_context && parm.found_context->ra_time == 0)
+		new_timeout(parm.found_context, iface_name, now);
+	      
 	      *up = context->next;
 	      free(context);
 	    }
@@ -636,8 +643,10 @@ static int add_prefixes(struct in6_addr *local,  int prefix,
                     off_link = (context->flags & CONTEXT_RA_OFF_LINK);
 		  }
 
-		param->first = 0;	
-		param->found_context = 1;
+		param->first = 0;
+		/* found_context is the _last_ one we found, so if there's 
+		   more than one, it's not the first. */
+		param->found_context = context;
 	      }
 
 	  /* configured time is ceiling */

src/rfc1035.c

@@ -1167,11 +1167,23 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
 static unsigned long crec_ttl(struct crec *crecp, time_t now)
 {
   /* Return 0 ttl for DHCP entries, which might change
-     before the lease expires. */
+     before the lease expires, unless configured otherwise. */
 
-  if  (crecp->flags & (F_IMMORTAL | F_DHCP))
-    return daemon->local_ttl;
+  if (crecp->flags & F_DHCP)
+    {
+      int conf_ttl = daemon->use_dhcp_ttl ? daemon->dhcp_ttl : daemon->local_ttl;
+      
+      /* Apply ceiling of actual lease length to configured TTL. */
+      if (!(crecp->flags & F_IMMORTAL) && (crecp->ttd - now) < conf_ttl)
+	return crecp->ttd - now;
+      
+      return conf_ttl;
+    }	  
   
+  /* Immortal entries other than DHCP are local, and hold TTL in TTD field. */
+  if (crecp->flags & F_IMMORTAL)
+    return crecp->ttd;
+
   /* Return the Max TTL value if it is lower then the actual TTL */
   if (daemon->max_ttl == 0 || ((unsigned)(crecp->ttd - now) < daemon->max_ttl))
     return crecp->ttd - now;
@@ -1835,7 +1847,7 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
   
   /* Advertise our packet size limit in our reply */
   if (have_pseudoheader)
-    len = add_pseudoheader(header, len, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit);
+    len = add_pseudoheader(header, len, (unsigned char *)limit, daemon->edns_pktsz, 0, NULL, 0, do_bit, 0);
   
   if (ad_reqd && sec_data)
     header->hb4 |= HB4_AD;

src/rfc2131.c

@@ -1308,7 +1308,7 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 		      /* If the user-class option started as counted strings, the first byte will be zero. */
 		      if (len != 0 && ucp[0] == 0)
 			ucp++, len--;
-		      lease_add_extradata(lease, ucp, len, 0);
+		      lease_add_extradata(lease, ucp, len, -1);
 		    }
 		}
 #endif

src/rrfilter.c

@@ -323,12 +323,12 @@ int expand_workspace(unsigned char ***wkspc, int *szp, int new)
 
   new += 5;
   
-  if (!(p = whine_malloc(new * sizeof(unsigned char **))))
+  if (!(p = whine_malloc(new * sizeof(unsigned char *))))
     return 0;  
   
   if (old != 0 && *wkspc)
     {
-      memcpy(p, *wkspc, old * sizeof(unsigned char **));
+      memcpy(p, *wkspc, old * sizeof(unsigned char *));
       free(*wkspc);
     }
   

src/tftp.c

@@ -103,8 +103,10 @@ void tftp_request(struct listener *listen, time_t now)
       if (listen->iface)
 	{
 	  addr = listen->iface->addr;
-	  mtu = listen->iface->mtu;
 	  name = listen->iface->name;
+	  mtu = listen->iface->mtu;
+	  if (daemon->tftp_mtu != 0 && daemon->tftp_mtu < mtu)
+	    mtu = daemon->tftp_mtu;
 	}
       else
 	{
@@ -234,9 +236,17 @@ void tftp_request(struct listener *listen, time_t now)
 
       strncpy(ifr.ifr_name, name, IF_NAMESIZE);
       if (ioctl(listen->tftpfd, SIOCGIFMTU, &ifr) != -1)
-	mtu = ifr.ifr_mtu;      
+	{
+	  mtu = ifr.ifr_mtu;  
+	  if (daemon->tftp_mtu != 0 && daemon->tftp_mtu < mtu)
+	    mtu = daemon->tftp_mtu;    
+	}
     }
 
+  /* Failed to get interface mtu - can use configured value. */
+  if (mtu == 0)
+    mtu = daemon->tftp_mtu;
+
   if (name)
     {
       /* check for per-interface prefix */ 
@@ -336,14 +346,15 @@ void tftp_request(struct listener *listen, time_t now)
 	    {
 	      if ((opt = next(&p, end)) && !option_bool(OPT_TFTP_NOBLOCK))
 		{
+		  /* 32 bytes for IP, UDP and TFTP headers, 52 bytes for IPv6 */
+		  int overhead = (listen->family == AF_INET) ? 32 : 52;
 		  transfer->blocksize = atoi(opt);
 		  if (transfer->blocksize < 1)
 		    transfer->blocksize = 1;
 		  if (transfer->blocksize > (unsigned)daemon->packet_buff_sz - 4)
 		    transfer->blocksize = (unsigned)daemon->packet_buff_sz - 4;
-		  /* 32 bytes for IP, UDP and TFTP headers */
-		  if (mtu != 0 && transfer->blocksize > (unsigned)mtu - 32)
-		    transfer->blocksize = (unsigned)mtu - 32;
+		  if (mtu != 0 && transfer->blocksize > (unsigned)mtu - overhead)
+		    transfer->blocksize = (unsigned)mtu - overhead;
 		  transfer->opt_blocksize = 1;
 		  transfer->block = 0;
 		}