Add hop count to mdp ping

- Allow mdp client to specify ttl
- Copy ttl into and out of overlay frame

commandline.c

@@ -833,9 +833,13 @@ int app_mdp_ping(int argc, const char *const *argv, struct command_line_option *
 	    {
 	      int *rxseq=(int *)&mdp.in.payload;
 	      long long *txtime=(long long *)&mdp.in.payload[4];
+	      int hop_count = 64 - mdp.in.ttl;
 	      time_ms_t delay = gettime_ms() - *txtime;
-	      printf("%s: seq=%d time=%lld ms%s%s\n",
-		     alloca_tohex_sid(mdp.in.src.sid),(*rxseq)-firstSeq+1,delay,
+	      printf("%s: seq=%d time=%lld hops=%d ms%s%s\n",
+		     alloca_tohex_sid(mdp.in.src.sid),
+		     (*rxseq)-firstSeq+1,
+		     delay,
+		     hop_count,
 		     mdp.packetTypeAndFlags&MDP_NOCRYPT?"":" ENCRYPTED",
 		     mdp.packetTypeAndFlags&MDP_NOSIGN?"":" SIGNED");
 	      // TODO Put duplicate pong detection here so that stats work properly.

keyring.c

@@ -1224,6 +1224,7 @@ int keyring_mapping_request(keyring_file *k, overlay_mdp_frame *req)
     /* and record the full length of this */
     req->out.payload_length = 1 + SAS_SIZE + slen;
     overlay_mdp_swap_src_dst(req);
+    req->out.ttl=0;
     req->packetTypeAndFlags=MDP_TX; /* crypt and sign */
     if (debug & DEBUG_KEYRING)
       DEBUGF("Sending SID:SAS mapping, %d bytes, %s:0x%X -> %s:0x%X",

overlay_mdp.c

@@ -372,6 +372,7 @@ int overlay_saw_mdp_containing_frame(struct overlay_frame *f, time_ms_t now)
   bzero(&mdp, sizeof(overlay_mdp_frame));
   
   mdp.in.queue = f->queue;
+  mdp.in.ttl = f->ttl;
   
   /* Get source and destination addresses */
   if (f->destination)
@@ -530,7 +531,8 @@ int overlay_saw_mdp_frame(overlay_mdp_frame *mdp, time_ms_t now)
 
 	  /* Swap addresses */
 	  overlay_mdp_swap_src_dst(mdp);
-
+	  mdp->out.ttl=0;
+	  
 	  /* Prevent echo:echo connections and the resulting denial of service from triggering endless pongs. */
 	  if (mdp->out.dst.port==MDP_PORT_ECHO) {
 	    RETURN(WHY("echo loop averted"));
@@ -710,7 +712,10 @@ int overlay_mdp_dispatch(overlay_mdp_frame *mdp,int userGeneratedFrameP,
   }else{
     frame->destination = find_subscriber(mdp->out.dst.sid, SID_SIZE, 1);
   }
-  frame->ttl=64; /* normal TTL (XXX allow setting this would be a good idea) */	
+  
+  frame->ttl=mdp->out.ttl;
+  if (frame->ttl==0) 
+    frame->ttl=64; /* default TTL */	
   
   if (!frame->destination || frame->destination->reachable == REACHABLE_SELF)
     {

overlay_packetformats.c

@@ -72,7 +72,6 @@ int process_incoming_frame(time_ms_t now, struct overlay_interface *interface, s
 
 // duplicate the frame and queue it
 int overlay_forward_payload(struct overlay_frame *f){
-  f->ttl--;
   if (f->ttl<=0)
     return 0;
   
@@ -226,6 +225,7 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
     
     /* Get time to live */
     f.ttl=ob_get(b);
+    f.ttl--;
 
     /* Decode length of remainder of frame */
     int payload_len=rfs_decode(b->bytes, &b->position);

overlay_payload.c

@@ -87,6 +87,8 @@ int overlay_frame_append_payload(overlay_interface *interface, struct overlay_fr
     goto cleanup;    
 
   /* Write out TTL */
+  if (p->ttl>64)
+    p->ttl=64;
   if (ob_append_byte(headers,p->ttl))
     goto cleanup;
 

serval.h

@@ -700,6 +700,7 @@ typedef struct overlay_mdp_data_frame {
   // temporary hack to improve reliability before implementing per-packet nack's
   int send_copies;
   int queue;
+  int ttl;
   unsigned char payload[MDP_MTU-100];
 } overlay_mdp_data_frame;
 

tests/routing

@@ -81,4 +81,26 @@ test_multihop_linear() {
    tfw_cat --stdout --stderr
 }
 
+setup_crowded_mess() {
+   setup_servald
+   assert_no_servald_processes
+# BCDE & DEFG form squares, ABC & FGH form triangles
+   foreach_instance +A +B +C +D +E +F +G +H create_single_identity
+   foreach_instance +A +B +C add_interface dummy1
+   foreach_instance +B +D add_interface dummy2
+   foreach_instance +C +E add_interface dummy3
+   foreach_instance +D +E add_interface dummy4
+   foreach_instance +D +F add_interface dummy5
+   foreach_instance +E +G add_interface dummy6
+   foreach_instance +F +G +H add_interface dummy7
+   foreach_instance +A +B +C +D +E +F +G +H start_routing_instance
+}
+
+doc_crowded_mess="Multiple possible paths"
+test_crowded_mess() {
+   set_instance +A
+   executeOk_servald mdp ping $SIDH 5
+   tfw_cat --stdout --stderr
+}
+
 runTests "$@"