Added distance function and changed some stuff.

Also fixed typo in Readme.

README.md

@@ -122,6 +122,6 @@ Proposal of a free as in freedom skype replacement:
                 Packet contents: [byte with value: 02][random 4 byte (ping_id)][char array (client node_id), length=32 bytes][char array: requested_node_id (node_id of which we want the ip), length=32 bytes]
                 Valid replies: a send_nodes packet
     
-                Send_nodes (response): [byte with value: 03][random 4 byte (ping_id)][Nodes in node format, length=40 * (number of nodes (maximum of 8 nodes)) bytes]
+                Send_nodes (response): [byte with value: 03][random 4 byte (ping_id)][Nodes in node format, length=38 * (number of nodes (maximum of 8 nodes)) bytes]
                 ex: 03[Node][Node][Node] 
 

core/DHT.c

@@ -9,6 +9,30 @@ int sendpacket(IP_Port ip_port, char * data, uint32_t length)
     return sendto(sock, data, length, 0, (struct sockaddr *)&addr, sizeof(addr));
 }
 
+//Compares client_id1 and client_id2 with client_id
+//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 i;
+    for(i = 0; i < CLIENT_ID_SIZE; i++)
+    {
+        if(abs(client_id[i] ^ client_id1[i]) < abs(client_id[i] ^ client_id2[i]))
+        {
+            return 1;
+        }
+        else if(abs(client_id[i] ^ client_id1[i]) > abs(client_id[i] ^ client_id2[i]))
+        {
+            return 2;
+        }
+        
+    }
+    
+    return 0;
+}
+
+
 //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)
 {
@@ -22,10 +46,10 @@ int addto_lists(IP_Port ip_port, char * client_id)
 //Currently incomplete: missing the ping_id part
 int pingreq(IP_Port ip_port)
 {
-    char data[37];
+    char data[5 + CLIENT_ID_SIZE];
     data[0] = 0;
     
-    memcpy(data + 5, self_client_id, 32);
+    memcpy(data + 5, self_client_id, CLIENT_ID_SIZE);
     
     sendpacket(ip_port, data, sizeof(data));
     
@@ -35,11 +59,11 @@ int pingreq(IP_Port ip_port)
 //Currently incomplete: missing the ping_id part
 int pingres(IP_Port ip_port, uint32_t ping_id)
 {
-    char data[37];
+    char data[5 + CLIENT_ID_SIZE];
     data[0] = 1;
     
     memcpy(data + 1, &ping_id, 4);
-    memcpy(data + 5, self_client_id, 32);
+    memcpy(data + 5, self_client_id, CLIENT_ID_SIZE);
     
     sendpacket(ip_port, data, sizeof(data));
     
@@ -49,11 +73,11 @@ int pingres(IP_Port ip_port, uint32_t ping_id)
 //Currently incomplete: missing the ping_id part
 int getnodes(IP_Port ip_port, char * client_id)
 {
-   char data[69];
+   char data[5 + CLIENT_ID_SIZE*2];
    data[0] = 2;
    
-   memcpy(data + 5, self_client_id, 32);
+   memcpy(data + 5, self_client_id, CLIENT_ID_SIZE);
-   memcpy(data + 37, client_id, 32);
+   memcpy(data + 5 + CLIENT_ID_SIZE, client_id, CLIENT_ID_SIZE);
    
    sendpacket(ip_port, data, sizeof(data));
 }
@@ -62,11 +86,11 @@ int getnodes(IP_Port ip_port, char * client_id)
 //Currently incomplete: missing the ping_id part
 int sendnodes(IP_Port ip_port, char * client_id)
 {
-   char data[325];
+   char data[5 + (CLIENT_ID_SIZE + 6)*8];
    data[0] = 3;
    
-   memcpy(data + 5, self_client_id, 32);
+   memcpy(data + 5, self_client_id, CLIENT_ID_SIZE);
-   memcpy(data + 37, client_id, 32);
+   memcpy(data + 5 + CLIENT_ID_SIZE, client_id, CLIENT_ID_SIZE);
    
    sendpacket(ip_port, data, sizeof(data));
 }
@@ -79,28 +103,50 @@ int sendnodes(IP_Port ip_port, char * client_id)
 
 int handle_pingreq(char * packet, uint32_t length, IP_Port source)
 {
+    if(length != 5 + CLIENT_ID_SIZE)
+    {
+        return 1;
+    }
+    
     uint32_t ping_id;
     
     memcpy(&ping_id, packet + 1, 4);
-    
     pingres(source, ping_id);
     
+    addto_lists(source, packet + 5);
+    
+    return 0;
 }
 
 int handle_pingres(char * packet, uint32_t length, IP_Port source)
 {
+    if(length != (5 + CLIENT_ID_SIZE))
+    {
+        return 1;
+    }
     
     
 }
 
 int handle_getnodes(char * packet, uint32_t length, IP_Port source)
 {
+    if(length != (5 + CLIENT_ID_SIZE*2))
+    {
+        return 1;
+    }
     
     
+    addto_lists(source, packet + 5);
+    
+    return 0;   
 }
 
 int handle_sendnodes(char * packet, uint32_t length, IP_Port source)
 {
+    if(length > 325 || (length - 5) % (CLIENT_ID_SIZE + 6) != 0)
+    {
+        return 1;
+    } 
     
     
 }
@@ -148,14 +194,12 @@ void DHT_recvpacket(char * packet, uint32_t length, IP_Port source)
     switch (packet[0]) {
     case 0:
         handle_pingreq(packet, length, source);
-        //TODO: try to add requesting node to client_list if packet is valid
         break;        
     case 1:
         handle_pingres(packet, length, source);
         break;        
     case 2:
         handle_getnodes(packet, length, source);
-        //TODO: try to add requesting node to client_list if packet is valid
         break;        
     case 3:
         handle_sendnodes(packet, length, source);
@@ -171,6 +215,7 @@ void DHT_recvpacket(char * packet, uint32_t length, IP_Port source)
 
 
 
+
 void doDHT()
 {
     

core/DHT.h

@@ -18,6 +18,10 @@
 
 #endif
 
+//Current time, unix format
+#define unix_time() ((uint32_t)time(NULL))
+
+#define CLIENT_ID_SIZE 32
 
 typedef union
 {
@@ -36,7 +40,7 @@ typedef struct
 
 typedef struct
 {
-    char client_id[32];
+    char client_id[CLIENT_ID_SIZE];
     IP_Port ip_port;
     uint32_t timestamp;
     
@@ -45,7 +49,7 @@ typedef struct
 
 typedef struct
 {
-    char client_id[32];
+    char client_id[CLIENT_ID_SIZE];
     Client_data client_list[8];
     
 }Friend;
@@ -73,18 +77,18 @@ typedef struct
 
 
 //Add a new friend to the friends list
-//client_id must be 32 bytes long.
+//client_id must be CLIENT_ID_SIZE bytes long.
 void addfriend(char * client_id);
 
 //Delete a friend from the friends list
-//client_id must be 32 bytes long.
+//client_id must be CLIENT_ID_SIZE bytes long.
 //returns 0 if success
 //returns 1 if failure (client_id not in friends list)
 char delfriend(char * client_id);
 
 
 //Get ip of friend
-//client_id must be 32 bytes long.
+//client_id must be CLIENT_ID_SIZE bytes long.
 //ip must be 4 bytes long.
 //port must be 2 bytes long.
 //returns ip if success
@@ -110,7 +114,7 @@ void bootstrap(IP_Port ip_port);
 //Global variables
 
 //Our client id
-char self_client_id[32];
+char self_client_id[CLIENT_ID_SIZE];
 
 //Our UDP socket.
 //We only use one so it's much easier to have it as a global variable