Very basic start on the Tox messaging api.(Should give you a basic idea how it's gonna work)

core/Messenger.c

@@ -0,0 +1,95 @@
+/* Messenger.c
+* 
+* An implementation of a simple text chat only messenger on the tox network core.
+* 
+*/
+
+#include "Messenger.h"
+ 
+ 
+typedef struct
+{
+    uint8_t client_id[CLIENT_ID_SIZE];
+    
+    
+}Friend;
+ 
+#define MAX_NUM_FRIENDS 256
+
+Friend friendlist[MAX_NUM_FRIENDS];
+ 
+//add a friend
+//returns the friend number if success
+//return -1 if failure.
+int m_addfriend(uint8_t * client_id)
+{
+    
+    //add friend to the DHT
+    addfriend(uint8_t * client_id);
+    
+    send_friendrequest(uint8_t * public_key, IP_Port ip_port, uint8_t * data, uint32_t length);
+    
+}
+
+//remove a friend
+int m_delfriend(int friendnumber)
+{
+    //delete friend from DHT
+    delfriend(uint8_t * client_id);
+    
+}
+
+
+//return 1 if friend is online
+//return 0 if he is not
+int m_friendonline(int friendnumber)
+{
+    
+    
+}
+
+
+//send a text chat message to a friend.
+int m_sendmessage(int friendnumber)
+{
+    write_cryptpacket(int crypt_connection_id, uint8_t * data, uint32_t length);
+    
+}
+
+
+#define PORT 33445
+//run this at startup
+void initMessenger();
+{
+    new_keys();
+    IP ip;
+    ip.i = 0;
+    init_networking(ip, PORT);
+    
+}
+
+//the main loop that needs to be run at least 200 times per second.
+void doMessenger();
+{
+    IP_Port ip_port;
+    uint8_t data[MAX_UDP_PACKET_SIZE];
+    uint32_t length;
+    while(recievepacket(&ip_port, data, &length) != -1)
+    {
+        //if(rand() % 3 != 1)//simulate packet loss
+        //{
+        if(DHT_handlepacket(data, length, ip_port) && LosslessUDP_handlepacket(data, length, ip_port))
+        {
+            //if packet is discarded
+            printf("Received unhandled packet with length: %u\n", length);
+        }
+        else
+        {
+            printf("Received handled packet with length: %u\n", length);
+        }
+        //}
+    }
+    doDHT();
+    doLossless_UDP();
+    doNetCrypto();
+}

core/Messenger.h

@@ -0,0 +1,48 @@
+/* Messenger.h
+* 
+* An implementation of a simple text chat only messenger on the tox network core.
+* 
+*/
+ 
+ 
+#ifndef MESSENGER_H 
+#define MESSENGER_H  
+
+#include "net_crypto.h"
+#include "DHT.h"
+
+
+//add a friend
+//returns the friend number if success
+//return -1 if failure.
+int m_addfriend(uint8_t * client_id);
+
+
+//remove a friend
+int m_delfriend(int friendnumber);
+
+//return 1 if friend is online
+//return 0 if he is not
+int m_friendonline(int friendnumber);
+
+
+//send a text chat message to a friend.
+int m_sendmessage(int friendnumber);
+
+
+//set the function that will be executed when a friend request is recieved.
+int m_callback_friendrequest();
+
+
+//set the function that will be executed when a message from a friend is recieved.
+int m_callback_friendmessage();
+
+
+//run this at startup
+void initMessenger();
+
+
+//the main loop that needs to be run at least 200 times per second.
+void doMessenger();
+
+#endif

core/net_crypto.c

@@ -5,8 +5,25 @@
 * 
 * NOTE: This code has to be perfect. We don't mess around with encryption.
 *
-*/
+ 
+    Copyright (C) 2013 Tox project All Rights Reserved.
 
+    This file is part of Tox.
+
+    Tox is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Tox is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Tox.  If not, see <http://www.gnu.org/licenses/>.
+    
+*/
 
 #include "net_crypto.h"
 

core/net_crypto.h

@@ -2,8 +2,25 @@
 * 
 * Functions for the core network crypto.
 *
-*/
+ 
+    Copyright (C) 2013 Tox project All Rights Reserved.
 
+    This file is part of Tox.
+
+    Tox is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Tox is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Tox.  If not, see <http://www.gnu.org/licenses/>.
+    
+*/
 #ifndef NET_CRYPTO_H 
 #define NET_CRYPTO_H