Fix crash in DHCPv6 information-request handler.

CHANGELOG

@@ -30,7 +30,19 @@ version 2.66
 	    Don't send the default DHCP option advertising dnsmasq as
 	    the local DNS server if dnsmasq is configured to not act
 	    as DNS server, or it's configured to a non-standard port.
-  
+ 
+            Add DNSMASQ_CIRCUIT_ID, DNSMASQ_SUBCRIBER_ID,
+            DNSMASQ_REMOTE_ID variables to the environment of the
+            lease-change script (and the correponding Lua). These hold
+            information inserted into the DHCP request by a DHCP relay
+            agent. Thanks to Lakefield Communications for providing a
+            bounty for this addition.
+ 
+	    Fixed crash, introduced in 2.64, whilst handling DHCPv6
+	    information-requests with some common configurations.
+	    Thanks to Robert M. Albrecht for the bug report and 
+	    chasing the problem.
+
 
 version 2.65
 	    Fix regression which broke forwarding of queries sent via

man/dnsmasq.8

@@ -1230,6 +1230,9 @@ For IPv4 only:
 
 DNSMASQ_CLIENT_ID if the host provided a client-id.
 
+DNSMASQ_CIRCUIT_ID, DNSMASQ_SUBSCRIBER_ID, DNSMASQ_REMOTE_ID if a
+DHCP relay-agent added any of these options.
+ 
 If the client provides vendor-class, DNSMASQ_VENDOR_CLASS.
 
 For IPv6 only:

src/helper.c

@@ -397,6 +397,9 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 		  buf = grab_extradata_lua(buf, end, "cpewan_oui");
 		  buf = grab_extradata_lua(buf, end, "cpewan_serial");   
 		  buf = grab_extradata_lua(buf, end, "cpewan_class");
+		  buf = grab_extradata_lua(buf, end, "circuit_id");
+		  buf = grab_extradata_lua(buf, end, "subscriber_id");
+		  buf = grab_extradata_lua(buf, end, "remote_id");
 		}
 	      
 	      buf = grab_extradata_lua(buf, end, "tags");
@@ -528,10 +531,13 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
 	      buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_OUI", &err);
 	      buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_SERIAL", &err);   
 	      buf = grab_extradata(buf, end, "DNSMASQ_CPEWAN_CLASS", &err);
+	      buf = grab_extradata(buf, end, "DNSMASQ_CIRCUIT_ID", &err);
+	      buf = grab_extradata(buf, end, "DNSMASQ_SUBSCRIBER_ID", &err);
+	      buf = grab_extradata(buf, end, "DNSMASQ_REMOTE_ID", &err);
 	    }
 	  
 	  buf = grab_extradata(buf, end, "DNSMASQ_TAGS", &err);
-	  
+
 	  if (is6)
 	    buf = grab_extradata(buf, end, "DNSMASQ_RELAY_ADDRESS", &err);
 	  else if (data.giaddr.s_addr != 0)

src/rfc2131.c

@@ -1256,7 +1256,20 @@ size_t dhcp_reply(struct dhcp_context *context, char *iface_name, int int_index,
 		  add_extradata_opt(lease, oui);
 		  add_extradata_opt(lease, serial);
 		  add_extradata_opt(lease, class);
-		  
+
+		  if ((opt = option_find(mess, sz, OPTION_AGENT_ID, 1)))
+		    {
+		      add_extradata_opt(lease, option_find1(option_ptr(opt, 0), option_ptr(opt, option_len(opt)), SUBOPT_CIRCUIT_ID, 1));
+		      add_extradata_opt(lease, option_find1(option_ptr(opt, 0), option_ptr(opt, option_len(opt)), SUBOPT_SUBSCR_ID, 1));
+		      add_extradata_opt(lease, option_find1(option_ptr(opt, 0), option_ptr(opt, option_len(opt)), SUBOPT_REMOTE_ID, 1));
+		    }
+		  else
+		    {
+		      add_extradata_opt(lease, NULL);
+		      add_extradata_opt(lease, NULL);
+		      add_extradata_opt(lease, NULL);
+		    }
+
 		  /* space-concat tag set */
 		  if (!tagif_netid)
 		    add_extradata_opt(lease, NULL);

src/rfc3315.c

@@ -1027,7 +1027,7 @@ static int dhcp6_no_relay(int msg_type, struct in6_addr *link_address, struct dh
       {
 	/* We can't discriminate contexts based on address, as we don't know it.
 	   If there is only one possible context, we can use its tags */
-	if (context && !context->current)
+	if (context && context->netid.net && !context->current)
 	  {
 	    context->netid.next = NULL;
 	    context_tags =  &context->netid;