Don't ask for explanation of SIDs with dead routing links

overlay_address.c

@@ -259,7 +259,7 @@ void overlay_address_append(struct decode_context *context, struct overlay_buffe
       && !subscriber->send_full
       && subscriber == my_subscriber
       && context->point_to_point_device
-      && (context->encoding_header==0 || !context->interface->local_echo))
+      && ((context->flags & DECODE_FLAG_ENCODING_HEADER)==0 || !context->interface->local_echo))
     ob_append_byte(b, OA_CODE_P2P_ME);
   else if (context && subscriber==context->sender)
     ob_append_byte(b, OA_CODE_SELF);
@@ -271,7 +271,7 @@ void overlay_address_append(struct decode_context *context, struct overlay_buffe
       subscriber->send_full=0;
     }else{
       len=(subscriber->abbreviate_len+2)/2;
-      if (context && context->encoding_header)
+      if (context && (context->flags & DECODE_FLAG_ENCODING_HEADER))
 	len++;
       if (len>SID_SIZE)
 	len=SID_SIZE;
@@ -341,33 +341,34 @@ static int find_subscr_buffer(struct decode_context *context, struct overlay_buf
   
   if (!subscriber){
     WARN("Could not resolve address, no buffer supplied");
-    context->invalid_addresses=1;
+    context->flags|=DECODE_FLAG_INVALID_ADDRESS;
     return 0;
   }
   
   *subscriber=find_subscriber(id, len, 1);
   
   if (!*subscriber){
-    context->invalid_addresses=1;
+    context->flags|=DECODE_FLAG_INVALID_ADDRESS;
     
-    // generate a please explain in the passed in context
-    
-    // add the abbreviation you told me about
-    if (!context->please_explain){
-      context->please_explain = calloc(sizeof(struct overlay_frame),1);
-      if ((context->please_explain->payload = ob_new()) == NULL)
-	return -1;
-      ob_limitsize(context->please_explain->payload, MDP_MTU);
+    if ((context->flags & DECODE_FLAG_DONT_EXPLAIN) == 0){
+      // generate a please explain in the passed in context
+      
+      // add the abbreviation you told me about
+      if (!context->please_explain){
+	context->please_explain = calloc(sizeof(struct overlay_frame),1);
+	if ((context->please_explain->payload = ob_new()) == NULL)
+	  return -1;
+	ob_limitsize(context->please_explain->payload, MDP_MTU);
+      }
+      
+      // And I'll tell you about any subscribers I know that match this abbreviation, 
+      // so you don't try to use an abbreviation that's too short in future.
+      walk_tree(&root, 0, id, len, id, len, add_explain_response, context);
+      
+      INFOF("Asking for explanation of %s", alloca_tohex(id, len));
+      ob_append_byte(context->please_explain->payload, len);
+      ob_append_bytes(context->please_explain->payload, id, len);
     }
-    
-    // And I'll tell you about any subscribers I know that match this abbreviation, 
-    // so you don't try to use an abbreviation that's too short in future.
-    walk_tree(&root, 0, id, len, id, len, add_explain_response, context);
-    
-    INFOF("Asking for explanation of %s", alloca_tohex(id, len));
-    ob_append_byte(context->please_explain->payload, len);
-    ob_append_bytes(context->please_explain->payload, id, len);
-    
   }else{
     if (context)
       context->previous=*subscriber;
@@ -395,7 +396,7 @@ int overlay_address_parse(struct decode_context *context, struct overlay_buffer
 	context->previous=my_subscriber;
       }else{
 	WHYF("Could not resolve address on %s, this isn't a configured point to point link", context->interface->name);
-	context->invalid_addresses=1;
+	context->flags|=DECODE_FLAG_INVALID_ADDRESS;
       }
       return 0;
 
@@ -404,24 +405,26 @@ int overlay_address_parse(struct decode_context *context, struct overlay_buffer
         *subscriber=context->point_to_point_device;
 	context->previous=*subscriber;
       }else{
-	// add the abbreviation you told me about
-	if (!context->please_explain){
-	  context->please_explain = calloc(sizeof(struct overlay_frame),1);
-	  if ((context->please_explain->payload = ob_new()) == NULL)
-	    return -1;
-	  ob_limitsize(context->please_explain->payload, MDP_MTU);
+	if ((context->flags & DECODE_FLAG_DONT_EXPLAIN) == 0){
+	  // add the abbreviation you told me about
+	  if (!context->please_explain){
+	    context->please_explain = calloc(sizeof(struct overlay_frame),1);
+	    if ((context->please_explain->payload = ob_new()) == NULL)
+	      return -1;
+	    ob_limitsize(context->please_explain->payload, MDP_MTU);
+	  }
+	  
+	  INFOF("Asking for explanation of YOU");
+	  ob_append_byte(context->please_explain->payload, OA_CODE_P2P_YOU);
 	}
-	
-	INFOF("Asking for explanation of YOU");
-	ob_append_byte(context->please_explain->payload, OA_CODE_P2P_YOU);
-	context->invalid_addresses=1;
+	context->flags|=DECODE_FLAG_INVALID_ADDRESS;
       }
       return 0;
 
     case OA_CODE_SELF:
       if (!context->sender){
 	INFO("Could not resolve address, sender has not been set");
-	context->invalid_addresses=1;
+	context->flags|=DECODE_FLAG_INVALID_ADDRESS;
       }else{
 	*subscriber=context->sender;
 	context->previous=context->sender;
@@ -431,7 +434,7 @@ int overlay_address_parse(struct decode_context *context, struct overlay_buffer
     case OA_CODE_PREVIOUS:
       if (!context->previous){
 	INFO("Unable to decode previous address");
-	context->invalid_addresses=1;
+	context->flags|=DECODE_FLAG_INVALID_ADDRESS;
       }else{
 	*subscriber=context->previous;
       }

overlay_address.h

@@ -93,18 +93,17 @@ struct broadcast{
   unsigned char id[BROADCAST_LEN];
 };
 
+#define DECODE_FLAG_ENCODING_HEADER (1<<0)
+#define DECODE_FLAG_INVALID_ADDRESS (1<<1)
+#define DECODE_FLAG_DONT_EXPLAIN (1<<2)
+
 struct decode_context{
   struct overlay_interface *interface;
   int sender_interface;
   int packet_version;
   int encapsulation;
   struct socket_address addr;
-  union{
-    // only valid while decoding
-    int invalid_addresses;
-    // only valid while encoding
-    int encoding_header;
-  };
+  uint8_t flags;
   struct overlay_frame *please_explain;
   struct subscriber *sender;
   struct subscriber *previous;

overlay_mdp_services.c

@@ -289,7 +289,7 @@ static int overlay_mdp_service_trace(struct internal_mdp_header *header, struct
     ret=WHYF("Invalid destination SID");
     goto end;
   }
-  if (context.invalid_addresses){
+  if (context.flags & DECODE_FLAG_INVALID_ADDRESS){
     ret=WHYF("Unknown address in trace packet");
     goto end;
   }
@@ -306,7 +306,7 @@ static int overlay_mdp_service_trace(struct internal_mdp_header *header, struct
       ret=WHYF("Invalid SID in packet payload");
       goto end;
     }
-    if (context.invalid_addresses){
+    if (context.flags & DECODE_FLAG_INVALID_ADDRESS){
       ret=WHYF("Unknown SID in packet payload");
       goto end;
     }

overlay_olsr.c

@@ -171,7 +171,7 @@ static void parse_frame(struct overlay_buffer *buff){
   if (overlay_address_parse(&context, buff, &context.sender))
     goto end;
   
-  if (context.invalid_addresses)
+  if (context.flags & DECODE_FLAG_INVALID_ADDRESS)
     goto end;
   
   // locate the interface we should send outgoing unicast packets to
@@ -184,7 +184,7 @@ static void parse_frame(struct overlay_buffer *buff){
   if (overlay_address_parse(&context, buff, &frame.source))
     goto end;
   
-  if (context.invalid_addresses)
+  if (context.flags & DECODE_FLAG_INVALID_ADDRESS)
     goto end;
   
   // read source broadcast id
@@ -192,7 +192,7 @@ static void parse_frame(struct overlay_buffer *buff){
   if (overlay_broadcast_parse(buff, &frame.broadcast_id))
     goto end;
   
-  if (context.invalid_addresses)
+  if (context.flags & DECODE_FLAG_INVALID_ADDRESS)
     goto end;
   
   frame.modifiers=ob_get(buff);

overlay_packetformats.c

@@ -54,10 +54,10 @@ int overlay_packet_init_header(int packet_version, int encapsulation,
       && packet_version>=1
   )
     context->point_to_point_device = context->interface->other_device;
-  context->encoding_header=1;
+  context->flags = DECODE_FLAG_ENCODING_HEADER;
   overlay_address_append(context, buff, my_subscriber);
   
-  context->encoding_header=0;
+  context->flags = 0;
   context->sender = my_subscriber;
   
   int flags=0;
@@ -156,7 +156,7 @@ int parseMdpPacketHeader(struct decode_context *context, struct overlay_frame *f
   
   if (flags & PAYLOAD_FLAG_SENDER_SAME){
     if (!context->sender)
-      context->invalid_addresses=1;
+      context->flags |= DECODE_FLAG_INVALID_ADDRESS;
     frame->source = context->sender;
   }else{
     int ret=overlay_address_parse(context, buffer, &frame->source);
@@ -248,7 +248,7 @@ int parseMdpPacketHeader(struct decode_context *context, struct overlay_frame *f
   frame->packet_version = context->packet_version;
   
   // if we can't understand one of the addresses, skip processing the payload
-  if ((forward||process)&&context->invalid_addresses){
+  if ((forward||process)&& (context->flags & DECODE_FLAG_INVALID_ADDRESS)){
     if (IF_DEBUG(verbose))
       DEBUG(overlayframes, "Don't process or forward with invalid addresses");
     forward=process=0;
@@ -397,7 +397,7 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
   interface->recv_count++;
   
   while(ob_remaining(b)>0){
-    context.invalid_addresses=0;
+    context.flags = 0;
     struct subscriber *nexthop=NULL;
     bzero(f.broadcast_id.id, BROADCAST_LEN);
     

route_link.c

@@ -1338,8 +1338,6 @@ int link_receive(struct internal_mdp_header *header, struct overlay_buffer *payl
   char changed = 0;
 
   while(ob_remaining(payload)>0){
-    context.invalid_addresses=0;
-
     struct subscriber *receiver=NULL, *transmitter=NULL;
     struct overlay_interface *interface = NULL;
     size_t start_pos = ob_position(payload);
@@ -1350,6 +1348,10 @@ int link_receive(struct internal_mdp_header *header, struct overlay_buffer *payl
     int flags = ob_get(payload);
     if (flags<0)
       break;
+      
+    // If the link is dead, and we don't understand the SID, don't ask about it.
+    // We don't want or need to know.
+    context.flags = (flags & FLAG_NO_PATH)?DECODE_FLAG_DONT_EXPLAIN:0;
     if (overlay_address_parse(&context, payload, &receiver))
       break;
     int version = ob_get(payload);
@@ -1392,7 +1394,7 @@ int link_receive(struct internal_mdp_header *header, struct overlay_buffer *payl
     // jump to the position of the next record, even if there's more data we don't understand
     payload->position = start_pos + length;
 
-    if (context.invalid_addresses)
+    if (context.flags & DECODE_FLAG_INVALID_ADDRESS)
       continue;
 
     if (IF_DEBUG(verbose) || IF_DEBUG(ack))

tests/routing

@@ -630,7 +630,7 @@ test_offline() {
       wait_until --timeout=30 instance_offline +C
 }
 
-doc_lose_neighbours="Lose and regain neighbours due to turning off"
+doc_lose_neighbours="Lose and regain neighbours due to network timeout"
 setup_lose_neighbours() {
    setup_servald
    assert_no_servald_processes
@@ -687,6 +687,35 @@ finally_interfaceBounce() {
    simulator_quit
 }
 
+doc_noLinkPollution="Don't ask for explanation of links to dead nodes"
+setup_noLinkPollution() {
+   setup_servald
+   assert_no_servald_processes
+   start_simulator
+   simulator_command create "net1" "$SERVALD_VAR/dummy1/"
+# TODO re-roll identities until there's no possible SID prefix collision?
+   foreach_instance +A +B +C +D create_single_identity
+   foreach_instance +A +B +C +D add_servald_interface 1
+   foreach_instance +A +B +C start_servald_server
+   simulator_command up "net1"
+   wait_until path_exists +A +B
+   wait_until path_exists +A +C
+   foreach_instance +B +C stop_servald_server
+   set_instance +A
+   wait_until --timeout=30 instance_offline +B
+   wait_until --timeout=30 instance_offline +C
+   set_instance +D
+   start_servald_server
+   wait_until path_exists +A +D
+   wait_until path_exists +D +A
+}
+test_noLinkPollution() {
+   set_instance +D
+   executeOk_servald id allpeers
+   tfw_cat --stdout
+   assertStdoutLineCount '==' 3
+}
+
 setup_multi_interface() {
    setup_servald
    assert_no_servald_processes