Mark resent packets so they can be dropped

constants.h

@@ -98,6 +98,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #define PAYLOAD_FLAG_LONG_PAYLOAD (1<<3)
 #define PAYLOAD_FLAG_CIPHERED (1<<4)
 #define PAYLOAD_FLAG_SIGNED (1<<5)
+#define PAYLOAD_FLAG_DUPLICATE (1<<6)
 
 /* Time-to-live is a 'uint5_t'.
  */

overlay_address.h

@@ -95,6 +95,7 @@ struct broadcast{
 
 struct decode_context{
   struct overlay_interface *interface;
+  int sender_interface;
   struct sockaddr_in addr;
   int invalid_addresses;
   struct overlay_frame *please_explain;

overlay_packetformats.c

@@ -223,7 +223,18 @@ int parseMdpPacketHeader(struct decode_context *context, struct overlay_frame *f
     frame->type = ftype;
   }else
     frame->type=OF_TYPE_DATA;
-  
+
+  if (flags & PAYLOAD_FLAG_DUPLICATE){
+    int previous_seq = ob_get(buffer);
+    if (previous_seq == -1)
+      RETURN(WHY("Unable to read previous seq"));
+    // TODO unicast
+    if (link_received_duplicate(context->sender, context->interface, context->sender_interface, previous_seq, 0)){
+      if (config.debug.overlayframes)
+        DEBUG("Don't process or forward duplicate payloads");
+      forward=process=0;
+    }
+  }
   frame->modifiers=flags;
   
   // if we can't understand one of the addresses, skip processing the payload
@@ -246,11 +257,13 @@ int parseEnvelopeHeader(struct decode_context *context, struct overlay_interface
   
   int packet_flags = ob_get(buffer);
   
-  int sender_interface = 0;
+  context->sender_interface = 0;
+  context->interface = interface;
+
   int sender_seq = -1;
 
   if (packet_flags & PACKET_INTERFACE)
-    sender_interface = ob_get(buffer);
+    context->sender_interface = ob_get(buffer);
   
   if (packet_flags & PACKET_SEQ)
     sender_seq = ob_get(buffer)&0xFF;
@@ -288,7 +301,7 @@ int parseEnvelopeHeader(struct decode_context *context, struct overlay_interface
     if (addr && (context->sender->last_probe==0 || now - context->sender->last_probe > interface->tick_ms*10))
       overlay_send_probe(context->sender, *addr, interface, OQ_MESH_MANAGEMENT);
     
-    link_received_packet(context->sender, interface, sender_interface, sender_seq, packet_flags & PACKET_UNICAST);
+    link_received_packet(context->sender, interface, context->sender_interface, sender_seq, packet_flags & PACKET_UNICAST);
   }
   
   if (addr){

overlay_payload.c

@@ -23,8 +23,8 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "overlay_buffer.h"
 #include "overlay_packet.h"
 
-int overlay_frame_build_header(struct decode_context *context, struct overlay_buffer *buff, 
-			       int queue, int type, int modifiers, int ttl, 
+static int overlay_frame_build_header(struct decode_context *context, struct overlay_buffer *buff, 
+			       int queue, int type, int modifiers, int ttl, int previous_seq,
 			       struct broadcast *broadcast, struct subscriber *next_hop,
 			       struct subscriber *destination, struct subscriber *source)
 {
@@ -46,6 +46,8 @@ int overlay_frame_build_header(struct decode_context *context, struct overlay_bu
   
   if (type!=OF_TYPE_DATA)
     flags |= PAYLOAD_FLAG_LEGACY_TYPE;
+  if (previous_seq>=0)
+    flags |= PAYLOAD_FLAG_DUPLICATE;
   
   if (ob_append_byte(buff, flags)) return -1;
   
@@ -71,6 +73,10 @@ int overlay_frame_build_header(struct decode_context *context, struct overlay_bu
   if (flags & PAYLOAD_FLAG_LEGACY_TYPE){
     if (ob_append_byte(buff, type)) return -1;
   }
+
+  if (flags & PAYLOAD_FLAG_DUPLICATE){
+    if (ob_append_byte(buff, previous_seq)) return -1;
+  }
   
   return 0;
 }
@@ -99,7 +105,7 @@ int overlay_frame_append_payload(struct decode_context *context, overlay_interfa
     broadcast = &p->broadcast_id;
   }
   if (overlay_frame_build_header(context, b,
-			     p->queue, p->type, p->modifiers, p->ttl,
+			     p->queue, p->type, p->modifiers, p->ttl, p->sent_seq,
 			     broadcast, p->next_hop, 
 			     p->destination, p->source))
     goto cleanup;
@@ -137,7 +143,7 @@ int single_packet_encapsulation(struct overlay_buffer *b, struct overlay_frame *
 
   if (overlay_frame_build_header(&context, b,
 				 frame->queue, frame->type, 
-				 frame->modifiers, frame->ttl,
+				 frame->modifiers, frame->ttl, -1,
 				 broadcast, frame->next_hop, 
 				 frame->destination, frame->source))
     return -1;

route_link.c

@@ -744,6 +744,22 @@ int link_state_ack_soon(struct subscriber *subscriber){
   return 0;
 }
 
+// our neighbour is sending a duplicate frame, did we see the original?
+int link_received_duplicate(struct subscriber *subscriber, struct overlay_interface *interface, int sender_interface, int previous_seq, int unicast)
+{
+  // TODO better handling of unicast routes
+  if (unicast)
+    return 0;
+
+  struct neighbour *neighbour = get_neighbour(subscriber, 1);
+  struct neighbour_link *link=get_neighbour_link(neighbour, interface, sender_interface, unicast);
+
+  int offset = (link->ack_sequence - 1 - previous_seq)&0xFF;
+  if (offset < 32)
+    return link->ack_mask & (1<<offset);
+  return 0;
+}
+
 // track stats for receiving packets from this neighbour
 int link_received_packet(struct subscriber *subscriber, struct overlay_interface *interface, int sender_interface, int sender_seq, int unicast)
 {

serval.h

@@ -518,10 +518,6 @@ int overlay_packet_init_header(int encapsulation,
 			       struct decode_context *context, struct overlay_buffer *buff, 
 			       struct subscriber *destination, 
 			       char unicast, char interface, int seq);
-int overlay_frame_build_header(struct decode_context *context, struct overlay_buffer *buff, 
-			       int queue, int type, int modifiers, int ttl, 
-			       struct broadcast *broadcast, struct subscriber *next_hop,
-			       struct subscriber *destination, struct subscriber *source);
 int overlay_interface_args(const char *arg);
 void overlay_rhizome_advertise(struct sched_ent *alarm);
 int overlay_add_local_identity(unsigned char *s);
@@ -829,6 +825,7 @@ extern long long bundles_available;
 extern char crash_handler_clue[1024];
 
 
+int link_received_duplicate(struct subscriber *subscriber, struct overlay_interface *interface, int sender_interface, int previous_seq, int unicast);
 int link_received_packet(struct subscriber *subscriber, struct overlay_interface *interface, int sender_interface, int sender_seq, int unicode);
 int link_receive(overlay_mdp_frame *mdp);
 void link_explained(struct subscriber *subscriber);

tests/routing

@@ -363,6 +363,7 @@ test_multi_interface() {
    wait_until multi_has_link $SIDA
 }
 
+# TODO assert that all packets arrive? assert that no duplicates arrive?
 doc_ping_unreliable="Ping over a 1-hop unreliable link"
 setup_ping_unreliable() {
   setup_servald