2 files changed, 108 insertions, 7 deletions

diff --git a/core/DHT.c b/core/DHT.c
index 80a54551..5a48c7b6 100644
--- a/core/DHT.c
+++ b/core/DHT.c
@@ -13,9 +13,9 @@ int sendpacket(IP_Port ip_port, char * data, uint32_t length)
 //return 0 if both are same distance
 //return 1 if client_id1 is closer.
 //return 2 if client_id2 is closer.
-int id_distance(char * client_id, char * client_id1, char * client_id2)
+int id_closest(char * client_id, char * client_id1, char * client_id2)
 {
-    int i;
+    uint32_t i;
     for(i = 0; i < CLIENT_ID_SIZE; i++)
     {
         if(abs(client_id[i] ^ client_id1[i]) < abs(client_id[i] ^ client_id2[i]))
@@ -32,11 +32,97 @@ int id_distance(char * client_id, char * client_id1, char * client_id2)
     return 0;
 }
 
+//check if client with client_id is already in list of length length.
+//return True(1) or False(0)
+int client_in_list(Client_data * list, uint32_t length, char * client_id)
+{
+    uint32_t i, j;
+    for(i = 0; i < length; i++)
+    {
+        for(j = 0; j < CLIENT_ID_SIZE; j++)
+        {
+        
+            if(list[i].client_id[j] != client_id[j])
+            {
+                break;
+            }
+        }
+        if((j - 1) == CLIENT_ID_SIZE)
+        {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+//the number of seconds for a non responsive node to become bad.
+#define BAD_NODE_TIMEOUT 130
+
+//replace first bad (or empty) node with this one
+//return 0 if successfull
+//return 1 if not (list contains no bad nodes)
+int replace_bad(Client_data * list, uint32_t length, char * client_id, IP_Port ip_port)
+{
+    uint32_t i;
+    for(i = 0; i < length; i++)
+    {
+        if(list[i].timestamp + BAD_NODE_TIMEOUT < unix_time())
+        {
+            memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
+            list[i].ip_port = ip_port;
+            list[i].timestamp = unix_time();
+            return 0;
+        }
+    }
+    return 1;
+}
+
+//replace the first good node further to the comp_client_id than that of the client_id 
+int replace_good(Client_data * list, uint32_t length, char * client_id, IP_Port ip_port, char * comp_client_id)
+{
+    uint32_t i;
+    for(i = 0; i < length; i++)
+    {
+        if(id_closest(comp_client_id, list[i].client_id, client_id) == 2)
+        {
+            memcpy(list[i].client_id, client_id, CLIENT_ID_SIZE);
+            list[i].ip_port = ip_port;
+            list[i].timestamp = unix_time();
+            return 0;
+        }
+    }
+    return 1;
+}
 
 //Attempt to add client with ip_port and client_id to the friends client list and close_clientlist
 int addto_lists(IP_Port ip_port, char * client_id)
 {
+    uint32_t i, j;
     
+    //NOTE: current behaviour if there are two clients with the same id is to only keep one (the first one)
+    if(!client_in_list(close_clientlist, LCLIENT_LIST, client_id))
+    {
+         
+        if(replace_bad(close_clientlist, LCLIENT_LIST, client_id, ip_port))
+        {
+            //if we can't replace bad nodes we try replacing good ones
+            replace_good(close_clientlist, LCLIENT_LIST, client_id, ip_port, self_client_id);
+        }
+        
+    }
+    for(i = 0; i < num_friends; i++)
+    {
+        if(!client_in_list(friends_list[i].client_list, LCLIENT_LIST, client_id))
+        {
+            
+            if(replace_bad(friends_list[i].client_list, LCLIENT_LIST, client_id, ip_port))
+            {
+                //if we can't replace bad nodes we try replacing good ones
+                replace_good(friends_list[i].client_list, LCLIENT_LIST, client_id, ip_port, self_client_id);
+            }
+            
+        }  
+    }
     
     
 }
@@ -113,7 +199,7 @@ int handle_pingreq(char * packet, uint32_t length, IP_Port source)
     memcpy(&ping_id, packet + 1, 4);
     pingres(source, ping_id);
     
-    addto_lists(source, packet + 5);
+    
     
     return 0;
 }
@@ -125,7 +211,7 @@ int handle_pingres(char * packet, uint32_t length, IP_Port source)
         return 1;
     }
     
-    
+    addto_lists(source, packet + 5);
 }
 
 int handle_getnodes(char * packet, uint32_t length, IP_Port source)
@@ -136,7 +222,7 @@ int handle_getnodes(char * packet, uint32_t length, IP_Port source)
     }
     
     
-    addto_lists(source, packet + 5);
+    
     
     return 0;   
 }
@@ -147,7 +233,7 @@ int handle_sendnodes(char * packet, uint32_t length, IP_Port source)
     {
         return 1;
     } 
-    
+    addto_lists(source, packet + 5);
     
 }
 
@@ -212,8 +298,23 @@ void DHT_recvpacket(char * packet, uint32_t length, IP_Port source)
 
 }
 
+//Ping each client in the "friends" list every 60 seconds.
+//Send a get nodes request every 20 seconds to a random good node for each "friend" in our "friends" list.
+void doFriends()
+{
+    
+    
+    
+}
 
 
+void doClose()
+{
+    
+    
+    
+}
+
 
 
 void doDHT()
diff --git a/core/DHT.h b/core/DHT.h
index c346608d..880cbf8e 100644
--- a/core/DHT.h
+++ b/core/DHT.h
@@ -92,7 +92,7 @@ char delfriend(char * client_id);
 //ip must be 4 bytes long.
 //port must be 2 bytes long.
 //returns ip if success
-//returns ip of 0 if failure (This means the friend is either offline of we have not found him yet.)
+//returns ip of 0 if failure (This means the friend is either offline or we have not found him yet.)
 IP_Port getfriendip(char * client_id);