From 0538e95be8dc7077e227b40bcf9c57201867f782 Mon Sep 17 00:00:00 2001
From: Jeremy Lakeman <Jeremy.Lakeman@gmail.com>
Date: Wed, 19 Sep 2012 15:55:29 +0930
Subject: [PATCH] Reduce the potential for packet storms

---
 dataformats.c       |  9 +++++++++
 overlay_interface.c |  5 ++++-
 overlay_mdp.c       | 23 +++++++----------------
 serval.h            |  2 ++
 4 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/dataformats.c b/dataformats.c
index 5c7cc672..21132ce9 100644
--- a/dataformats.c
+++ b/dataformats.c
@@ -57,6 +57,15 @@ int is_xstring(const char *text, int len)
   return _is_xstring(text, len);
 }
 
+/* Does this whole buffer contain the same value? */
+int is_all_matching(unsigned char *ptr, int len, int value){
+  int i;
+  for (i=0;i<len;i++)
+    if (ptr[i]!=value)
+      return 0;
+  return 1;
+}
+
 char *tohex(char *dstHex, const unsigned char *srcBinary, size_t bytes)
 {
   char *p;
diff --git a/overlay_interface.c b/overlay_interface.c
index 28952068..8b0a9d40 100644
--- a/overlay_interface.c
+++ b/overlay_interface.c
@@ -1074,8 +1074,11 @@ overlay_stuff_packet(struct outgoing_packet *packet, overlay_txqueue *queue, tim
 	  
 	case REACHABLE_BROADCAST:
 	  if (!frame->sendBroadcast){
+	    if (frame->ttl>2)
+	      frame->ttl=2;
 	    frame->sendBroadcast=1;
-	    overlay_broadcast_generate_address(&frame->broadcast_id);
+	    if (is_all_matching(frame->broadcast_id.id, BROADCAST_LEN, 0))
+	      overlay_broadcast_generate_address(&frame->broadcast_id);
 	    int i;
 	    for(i=0;i<OVERLAY_MAX_INTERFACES;i++)
 	      frame->broadcast_sent_via[i]=0;
diff --git a/overlay_mdp.c b/overlay_mdp.c
index a44a7512..2ae2132b 100644
--- a/overlay_mdp.c
+++ b/overlay_mdp.c
@@ -37,22 +37,10 @@ struct sched_ent mdp_named={
 };
 
 // is the SID entirely 0xFF?
-static int is_broadcast(const unsigned char *sid){
-  int i;
-  for (i=0;i<SID_SIZE;i++)
-    if (sid[i]!=0xFF) 
-      return 0;
-  return 1;
-}
+#define is_broadcast(SID) is_all_matching(SID, SID_SIZE, 0xFF)
 
 // is the SID entirely 0x00?
-static int is_sid_any(unsigned char *sid){
-  int i;
-  for (i=0;i<SID_SIZE;i++)
-    if (sid[i])
-      return 0;
-  return 1;
-}
+#define is_sid_any(SID) is_all_matching(SID, SID_SIZE, 0)
 
 int overlay_mdp_setup_sockets()
 {
@@ -431,8 +419,8 @@ int overlay_saw_mdp_frame(overlay_mdp_frame *mdp, time_ms_t now)
        more prudent path.
     */
 
-    if (0)
-      WHYF("Received packet with listener (MDP ports: src=%s*:%d, dst=%d)",
+    if (debug & DEBUG_MDPREQUESTS) 
+      DEBUGF("Received packet with listener (MDP ports: src=%s*:%d, dst=%d)",
 	   alloca_tohex(mdp->out.src.sid, 7),
 	   mdp->out.src.port,mdp->out.dst.port);
 
@@ -499,6 +487,9 @@ int overlay_saw_mdp_frame(overlay_mdp_frame *mdp, time_ms_t now)
 	  bcopy(&mdp->out.payload[0],&did[0],pll);
 	  did[pll]=0;
 	  
+	  if (debug & DEBUG_MDPREQUESTS)
+	    DEBUG("MDP_PORT_DNALOOKUP");
+	  
 	  int results=0;
 	  while(keyring_find_did(keyring,&cn,&in,&kp,did))
 	    {
diff --git a/serval.h b/serval.h
index 6c6a6c2d..23c97f79 100644
--- a/serval.h
+++ b/serval.h
@@ -456,6 +456,8 @@ int fromhexstr(unsigned char *dstBinary, const char *srcHex, size_t bytes);
 int hexvalue(char c);
 char *str_toupper_inplace(char *s);
 
+int is_all_matching(unsigned char *ptr, int len, int value);
+
 int str_is_subscriber_id(const char *sid);
 int strn_is_subscriber_id(const char *sid, size_t *lenp);
 int str_is_did(const char *did);