From f9287149dd24388edcf81a77c369601eb80198a9 Mon Sep 17 00:00:00 2001
From: Jeremy Lakeman <Jeremy.Lakeman@gmail.com>
Date: Thu, 6 Sep 2012 15:21:31 +0930
Subject: [PATCH] Setup unicast return address when receiving unicast packet

---
 overlay_address.c       | 21 ++++++++++++++++++++-
 overlay_address.h       |  1 +
 overlay_olsr.c          | 10 ++++------
 overlay_packetformats.c | 13 +++++++++++++
 overlay_route.c         |  3 ++-
 5 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/overlay_address.c b/overlay_address.c
index 071745a0..d3b3f7f3 100644
--- a/overlay_address.c
+++ b/overlay_address.c
@@ -160,13 +160,32 @@ int subscriber_is_reachable(struct subscriber *subscriber){
   
   if (subscriber->reachable==REACHABLE_DIRECT
       && !(subscriber->interface
-	 && subscriber->interface->state==INTERFACE_STATE_UP)
+      && subscriber->interface->state==INTERFACE_STATE_UP)
       )
     return REACHABLE_NONE;
   
   return subscriber->reachable;
 }
 
+// mark the subscriber as reachable via reply unicast packet
+int reachable_unicast(struct subscriber *subscriber, overlay_interface *interface, struct in_addr addr, int port){
+  if (subscriber->reachable!=REACHABLE_NONE)
+    return WHYF("Subscriber %s is already reachable", alloca_tohex_sid(subscriber->sid));
+  
+  if (subscriber->node)
+    return WHYF("Subscriber %s is already known for overlay routing", alloca_tohex_sid(subscriber->sid));
+  
+  subscriber->interface = interface;
+  subscriber->reachable = REACHABLE_DIRECT;
+  subscriber->address.sin_family = AF_INET;
+  subscriber->address.sin_addr = addr;
+  subscriber->address.sin_port = port;
+  
+  // may be used in tests
+  DEBUGF("ADD DIRECT ROUTE TO %s via %s", alloca_tohex_sid(subscriber->sid), inet_ntoa(addr));
+  return 0;
+}
+
 // generate a new random broadcast address
 int overlay_broadcast_generate_address(struct broadcast *addr)
 {
diff --git a/overlay_address.h b/overlay_address.h
index d2d72292..9067663b 100644
--- a/overlay_address.h
+++ b/overlay_address.h
@@ -98,6 +98,7 @@ extern struct subscriber *my_subscriber;
 struct subscriber *find_subscriber(const unsigned char *sid, int len, int create);
 void enum_subscribers(struct subscriber *start, int(*callback)(struct subscriber *, void *), void *context);
 int subscriber_is_reachable(struct subscriber *subscriber);
+int reachable_unicast(struct subscriber *subscriber, overlay_interface *interface, struct in_addr addr, int port);
 
 int overlay_broadcast_drop_check(struct broadcast *addr);
 int overlay_broadcast_generate_address(struct broadcast *addr);
diff --git a/overlay_olsr.c b/overlay_olsr.c
index 8aa9cb41..fc440ea2 100644
--- a/overlay_olsr.c
+++ b/overlay_olsr.c
@@ -136,13 +136,10 @@ static void parse_frame(struct overlay_buffer *buff){
   
   if (frame.source->reachable==REACHABLE_NONE){
     // locate the interface we should send outgoing unicast packets to
-    frame.source->interface = overlay_interface_find(*addr);
-    if (frame.source->interface){
-      frame.source->reachable=REACHABLE_DIRECT;
-      frame.source->address.sin_family=AF_INET;
-      frame.source->address.sin_addr=*addr;
+    overlay_interface *interface = overlay_interface_find(*addr);
+    if (interface){
       // assume the port number of the other servald matches our local port number configuration
-      frame.source->address.sin_port=frame.source->interface->port;
+      reachable_unicast(frame.source, interface, *addr, interface->port);
     }
   }
   
@@ -214,6 +211,7 @@ static int send_packet(unsigned char *header, int header_len, unsigned char *pay
     .msg_iovlen=2,
   };
   
+  DEBUGF("Sending broadcast via olsr");
   if (sendmsg(read_watch.poll.fd, &msg, 0)<0){
     return WHY_perror("Sending packet");
   }
diff --git a/overlay_packetformats.c b/overlay_packetformats.c
index cafc8127..85b1fb9b 100644
--- a/overlay_packetformats.c
+++ b/overlay_packetformats.c
@@ -269,6 +269,19 @@ int packetOkOverlay(struct overlay_interface *interface,unsigned char *packet, s
       goto next;
     }
     
+    // HACK, change to packet transmitter when packet format includes that.
+    if (f.type!=OF_TYPE_SELFANNOUNCE && 
+	f.source->reachable == REACHABLE_NONE && 
+	!f.source->node &&
+	!interface->fileP &&
+	recvaddr->sa_family==AF_INET){
+      struct sockaddr_in *addr=(struct sockaddr_in *)recvaddr;
+      
+      // mark this subscriber as reachable directly via unicast.
+      reachable_unicast(f.source, interface, addr->sin_addr, addr->sin_port);
+    }
+    
+    
     f.payload = ob_slice(b, b->position, next_payload - b->position);
     if (!f.payload){
       WHY("Payload length is longer than remaining packet size");
diff --git a/overlay_route.c b/overlay_route.c
index 882dfcca..ca8d60f7 100644
--- a/overlay_route.c
+++ b/overlay_route.c
@@ -183,7 +183,8 @@ overlay_node *get_node(struct subscriber *subscriber, int create){
     subscriber->node = (overlay_node *)malloc(sizeof(overlay_node));
     memset(subscriber->node,0,sizeof(overlay_node));
     subscriber->node->subscriber = subscriber;
-    
+    // if we're taking over routing calculations, make sure we invalidate any other calculations first
+    subscriber->reachable=REACHABLE_NONE;
     // This info message is used by tests; don't alter or remove it.
     INFOF("ADD OVERLAY NODE sid=%s", alloca_tohex_sid(subscriber->sid));
   }