Preserve existing log file permissions when adding group-write bit.

Commit 1f8f78a49b ("Add root group writeable flag to log file")
introduced a fchmod() call in log_start() that resets the file mode
to a hardcoded value (0660), discarding any pre-existing permissions.
This broke our usage of dnsmasq where we create the log file with
specific permissions before starting dnsmasq in an LXC container
namespace, so that unprivileged users inside the container can read
the log. The hardcoded mode strips those permissions on startup.

Use the existing stat result to OR in S_IWGRP instead, equivalent
to chmod g+w, so that only the group-write bit is added without
disturbing other permission bits.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -1,4 +1,4 @@
-# dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+# dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by

src/arp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/auth.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/blockdata.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/bpf.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/cache.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -2331,7 +2331,7 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
     return;
 
   /* build query type string if requested */
-  if (!(flags & (F_SERVER | F_IPSET | F_QUERY)) && type > 0)
+  if (!(flags & (F_SERVER | F_IPSET | F_QUERY | F_KEYTAG | F_RR)) && type > 0)
     arg = querystr(arg, type);
 
   dest = arg;
@@ -2347,19 +2347,25 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
     {
       dest = daemon->addrbuff;
 
-       if (flags & F_RR)
+      if (flags & F_RR)
-	 {
+	{
-	   if (flags & F_KEYTAG)
+	  if (flags & F_KEYTAG)
-	     dest = querystr(NULL, addr->rrblock.rrtype);
+	    dest = querystr(NULL, addr->rrblock.rrtype);
-	   else
+	  else
-	     dest = querystr(NULL, addr->rrdata.rrtype);
+	    dest = querystr(NULL, addr->rrdata.rrtype);
-	 }
+	}
-       else if (flags & F_KEYTAG)
+#ifdef HAVE_DNSSEC
-	sprintf(daemon->addrbuff, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
+      else if (flags & F_KEYTAG)
+	{
+	  snprintf(daemon->addrbuff, ADDRSTRLEN, arg, addr->log.keytag, addr->log.algo, addr->log.digest);
+	  if (type)
+	    extra = " (not supported)";
+	}
+#endif
       else if (flags & F_RCODE)
 	{
 	  unsigned int rcode = addr->log.rcode;
-
+	  
 	  if (rcode == SERVFAIL)
 	    dest = "SERVFAIL";
 	  else if (rcode == REFUSED)

src/config.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,7 +15,7 @@
 */
 
 #define FTABSIZ 150 /* max number of outstanding requests (default) */
-#define MAX_PROCS 20 /* default max no children for TCP requests */
+#define MAX_PROCS 30 /* default max no children for TCP requests */
 #define CHILD_LIFETIME 150 /* secs 'till terminated (RFC1035 suggests > 120s) */
 #define TCP_MAX_QUERIES 100 /* Maximum number of queries per incoming TCP connection */
 #define TCP_TIMEOUT 5 /* timeout waiting to connect to an upstream server - double this for answer */

src/conntrack.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/crypto.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dbus.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dhcp-common.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dhcp-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dhcp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dhcp6-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dhcp6.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dns-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dnsmasq.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dnsmasq.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
  
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -14,7 +14,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#define COPYRIGHT "Copyright (c) 2000-2025 Simon Kelley"
+#define COPYRIGHT "Copyright (c) 2000-2026 Simon Kelley"
 
 /* We do defines that influence behavior of stdio.h, so complain
    if included too early. */

src/dnssec.c

@@ -1,5 +1,5 @@
 /* dnssec.c is Copyright (c) 2012 Giovanni Bajo <rasky@develer.com>
-           and Copyright (c) 2012-2025 Simon Kelley
+           and Copyright (c) 2012-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -950,10 +950,7 @@ int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, ch
 			   
 			   a.log.keytag = keytag;
 			   a.log.algo = algo;
-			   if (algo_digest_name(algo))
+			   log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", !algo_digest_name(algo));
-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu", 0);
-			   else
-			     log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %hu, algo %hu (not supported)", 0);
 			 }
 		     }
 				  
@@ -1101,7 +1098,7 @@ int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char
 		  a.log.keytag = keytag;
 		  a.log.algo = algo;
 		  a.log.digest = digest;
-		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu (not supported)", 0);
+		  log_query(F_NOEXTRA | F_KEYTAG | F_UPSTREAM, name, &a, "DS for keytag %hu, algo %hu, digest %hu", 1);
 		  neg_ttl = ttl;
 		} 
 	      else if ((key = blockdata_alloc((char*)p, rdlen - 4)))

src/domain-match.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/domain.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/dump.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/edns0.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/forward.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/helper.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/inotify.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
  
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/ip6addr.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/lease.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/log.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -113,7 +113,7 @@ int log_start(struct passwd *ent_pw, int errfd)
       struct stat ls;
       if (getgid() == 0 && fstat(log_fd, &ls) == 0 && ls.st_gid == 0 &&
 	  (ls.st_mode & S_IWGRP) == 0)
-	(void)fchmod(log_fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP);
+	(void)fchmod(log_fd, ls.st_mode | S_IWGRP);
       if (fchown(log_fd, ent_pw->pw_uid, -1) != 0)
 	ret = errno;
     }

src/loop.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/metrics.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/metrics.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
    
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/netlink.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/network.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/nftset.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/option.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -4960,7 +4960,8 @@ err:
 	      arg = NULL; /* provoke error below */
 	  }
 	
-	if (!domain || !arg || !(new->name = canonicalise_opt(domain)))
+	if (!domain || !arg || !new->intr ||
+	    !(new->name = canonicalise_opt(domain)))
 	  ret_err(option == LOPT_DYNHOST ?
 		  _("bad dynamic host") : _("bad interface name"));
 	

src/outpacket.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/pattern.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/poll.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/radv-protocol.h

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/radv.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/rfc1035.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/rfc2131.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/rfc3315.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -24,7 +24,7 @@ struct state {
   int clid_len, ia_type, interface, hostname_auth, lease_allocate;
   char *client_hostname, *hostname, *domain, *send_domain;
   struct dhcp_context *context;
-  struct in6_addr *link_address, *fallback, *ll_addr, *ula_addr;
+  struct in6_addr *relay_address, *fallback, *ll_addr, *ula_addr;
   unsigned int xid, fqdn_flags, iaid;
   char *iface_name;
   void *packet_options, *end;
@@ -34,7 +34,7 @@ struct state {
 };
 
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, time_t now);
+			     struct in6_addr *client_addr, struct in6_addr *link_address, time_t now);
 static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, time_t now);
 static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_opts);
 static void log6_packet(struct state *state, char *type, struct in6_addr *addr, char *string);
@@ -99,9 +99,8 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
   state.ula_addr = ula_addr;
   state.mac_len = 0;
   state.tags = NULL;
-  state.link_address = NULL;
+  
-
+  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, NULL, now))
-  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, now))
     return msg_type == DHCP6RELAYFORW ? DHCPV6_SERVER_PORT : DHCPV6_CLIENT_PORT;
 
   return 0;
@@ -109,7 +108,7 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
 
 /* This cost me blood to write, it will probably cost you blood to understand - srk. */
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, time_t now)
+			     struct in6_addr *client_addr, struct in6_addr *link_address, time_t now)
 {
   uint8_t *end = inbuff + sz;
   uint8_t *opts = inbuff + 34;
@@ -136,7 +135,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
       link_address == NULL means there's no relay in use, so we try and find the client's 
       MAC address from the local ND cache. */
       
-      if (!state->link_address)
+      if (!link_address)
 	get_client_mac(client_addr, state->interface, state->mac, &state->mac_len, &state->mac_type, now);
       else
 	{
@@ -144,9 +143,9 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  struct shared_network *share = NULL;
 	  state->context = NULL;
 
-	  if (!IN6_IS_ADDR_LOOPBACK(state->link_address) &&
+	  if (!IN6_IS_ADDR_LOOPBACK(link_address) &&
-	      !IN6_IS_ADDR_LINKLOCAL(state->link_address) &&
+	      !IN6_IS_ADDR_LINKLOCAL(link_address) &&
-	      !IN6_IS_ADDR_MULTICAST(state->link_address))
+	      !IN6_IS_ADDR_MULTICAST(link_address))
 	    for (c = daemon->dhcp6; c; c = c->next)
 	      {
 		for (share = daemon->shared_networks; share; share = share->next)
@@ -155,7 +154,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 		      continue;
 		    
 		    if (share->if_index != 0 ||
-			!IN6_ARE_ADDR_EQUAL(state->link_address, &share->match_addr6))
+			!IN6_ARE_ADDR_EQUAL(link_address, &share->match_addr6))
 		      continue;
 		    
 		    if ((c->flags & CONTEXT_DHCP) &&
@@ -168,8 +167,8 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 		if (share ||
 		    ((c->flags & CONTEXT_DHCP) &&
 		     !(c->flags & (CONTEXT_TEMPLATE | CONTEXT_OLD)) &&
-		     is_same_net6(state->link_address, &c->start6, c->prefix) &&
+		     is_same_net6(link_address, &c->start6, c->prefix) &&
-		     is_same_net6(state->link_address, &c->end6, c->prefix)))
+		     is_same_net6(link_address, &c->end6, c->prefix)))
 		  {
 		    c->preferred = c->valid = 0xffffffff;
 		    c->current = state->context;
@@ -179,7 +178,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  
 	  if (!state->context)
 	    {
-	      inet_ntop(AF_INET6, state->link_address, daemon->addrbuff, ADDRSTRLEN); 
+	      inet_ntop(AF_INET6, link_address, daemon->addrbuff, ADDRSTRLEN); 
 	      my_syslog(MS_DHCP | LOG_WARNING, 
 			_("no address range available for DHCPv6 request from relay at %s"),
 			daemon->addrbuff);
@@ -194,6 +193,8 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  return 0;
 	}
 
+      state->relay_address = link_address;
+
       return dhcp6_no_relay(state, msg_type, inbuff, sz, now);
     }
 
@@ -253,11 +254,12 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	      /* the packet data is unaligned, copy to aligned storage */
 	      memcpy(&align, inbuff + 2, IN6ADDRSZ); 
 
-
+	      /* RFC6221 para 4 says if link_address in encapulation
-	      /* RFC6221 para 4 */
+		 is zero, ignore it, and, by implication, use the link
-	      if (!IN6_IS_ADDR_UNSPECIFIED(&align))
+		 address of any enclosing encapsulation or, failing that
-		state->link_address = &align;
+		 of the arrival interface on the the server. */
-	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr, now))
+	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr,
+				     IN6_IS_ADDR_UNSPECIFIED(&align) ? link_address : &align, now))
 		return 0;
 	    }
 	  else
@@ -1977,10 +1979,10 @@ static void update_leases(struct state *state, struct dhcp_context *context, str
 		}
 	    }
 	  
-	  if (state->link_address)
+	  if (state->relay_address)
-	    inet_ntop(AF_INET6, state->link_address, daemon->addrbuff, ADDRSTRLEN);
+	    inet_ntop(AF_INET6, state->relay_address, daemon->addrbuff, ADDRSTRLEN);
 	  
-	  lease_add_extradata(lease, (unsigned char *)daemon->addrbuff, state->link_address ? strlen(daemon->addrbuff) : 0, 0);
+	  lease_add_extradata(lease, (unsigned char *)daemon->addrbuff, state->relay_address ? strlen(daemon->addrbuff) : 0, 0);
 	  
 	  if ((opt = opt6_find(state->packet_options, state->end, OPTION6_USER_CLASS, 2)))
 	    {

src/rrfilter.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/slaac.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/tftp.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/ubus.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

src/util.c

@@ -1,4 +1,4 @@
-/* dnsmasq is Copyright (c) 2000-2025 Simon Kelley
+/* dnsmasq is Copyright (c) 2000-2026 Simon Kelley
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by