Added basic Local/LAN discovery.

core/CMakeLists.txt

@@ -11,6 +11,7 @@ set(core_sources
         Lossless_UDP.c
         net_crypto.c
         friend_requests.c
+        LAN_discovery.c
         Messenger.c)
 
 add_library(core ${core_sources})

core/LAN_discovery.c

@@ -0,0 +1,78 @@
+/* LAN_discovery.c
+ * 
+ * LAN discovery implementation.
+ * 
+ */
+
+#include "routing.h"
+
+
+/*Return the broadcast ip
+  TODO: make it return the real one, not the 255.255.255.255 one.*/
+IP broadcast_ip()
+{
+    IP ip;
+    ip.i = ~0;
+    return ip;
+}
+
+/*return 0 if ip is a LAN ip
+  return -1 if it is not */
+int LAN_ip(IP ip)
+{
+    if(ip.c[0] == 127)/* Loopback */
+    {
+        return 0;
+    }
+    if(ip.c[0] == 10)/* 10.0.0.0 to 10.255.255.255 range */
+    {
+        return 0;
+    }
+    if(ip.c[0] == 172 && ip.c[1] >= 16 && ip.c[1] <= 31)/* 172.16.0.0 to 172.31.255.255 range */
+    {
+        return 0;
+    }
+    if(ip.c[0] == 192 && ip.c[1] == 168) /* 192.168.0.0 to 192.168.255.255 range */
+    {
+        return 0;
+    }
+    if(ip.c[0] == 169 && ip.c[1] == 254 && ip.c[2] != 0 && ip.c[2] != 255)/* 169.254.1.0 to 169.254.254.255 range */
+    {
+        return 0;
+    }
+    return -1;
+}
+
+int handle_LANdiscovery(uint8_t * packet, uint32_t length, IP_Port source)
+{
+    if(LAN_ip(source.ip) == -1)
+    {
+        return 1;
+    }
+    if(length != crypto_box_PUBLICKEYBYTES + 1)
+    {
+        return 1;
+    }
+    DHT_bootstrap(source, packet + 1);
+    return 0;
+}
+
+
+int send_LANdiscovery(uint16_t port)
+{
+    uint8_t data[crypto_box_PUBLICKEYBYTES + 1];
+    data[0] = 32;
+    memcpy(data + 1, self_public_key, crypto_box_PUBLICKEYBYTES);
+    IP_Port ip_port = {broadcast_ip(), port};
+    return sendpacket(ip_port, data, 1 + crypto_box_PUBLICKEYBYTES);
+}
+
+
+int LANdiscovery_handlepacket(uint8_t * packet, uint32_t length, IP_Port source)
+{
+    if(packet[0] == 32)
+    {
+        return handle_LANdiscovery(packet, length, source);
+    }
+    return 1;
+}

core/LAN_discovery.h

@@ -0,0 +1,28 @@
+/* LAN_discovery.h
+ * 
+ * LAN discovery implementation.
+ * 
+ */
+
+
+#ifndef LAN_DISCOVERY_H 
+#define LAN_DISCOVERY_H 
+
+
+#include "DHT.h"
+
+
+/*Send a LAN discovery pcaket to the broadcast address with port port*/
+int send_LANdiscovery(uint16_t port);
+
+
+/* if we receive a packet we call this function so it can be handled.
+   return 0 if packet is handled correctly.
+   return 1 if it didn't handle the packet or if the packet was shit. */
+int LANdiscovery_handlepacket(uint8_t * packet, uint32_t length, IP_Port source);
+
+
+
+
+
+#endif

core/Messenger.c

@@ -530,6 +530,22 @@ static void doInbound()
     }
 }
 
+/*Interval in seconds between LAN discovery packet sending*/
+#define LAN_DISCOVERY_INTERVAL 60
+
+static uint32_t last_LANdiscovery;
+
+/*Send a LAN discovery packet every LAN_DISCOVERY_INTERVAL seconds*/
+static void LANdiscovery()
+{
+    if(last_LANdiscovery + LAN_DISCOVERY_INTERVAL < unix_time())
+    {
+        send_LANdiscovery(htons(PORT));
+        last_LANdiscovery = unix_time();
+    }
+}
+
+
 /* the main loop that needs to be run at least 200 times per second. */
 void doMessenger()
 {
@@ -541,7 +557,8 @@ void doMessenger()
 #ifdef DEBUG
         /* if(rand() % 3 != 1) //simulate packet loss */
         /* { */
-        if(DHT_handlepacket(data, length, ip_port) && LosslessUDP_handlepacket(data, length, ip_port) && friendreq_handlepacket(data, length, ip_port))
+        if(DHT_handlepacket(data, length, ip_port) && LosslessUDP_handlepacket(data, length, ip_port) && 
+        friendreq_handlepacket(data, length, ip_port) && LANdiscovery_handlepacket(data, length, ip_port))
         {
             /* if packet is discarded */
             printf("Received unhandled packet with length: %u\n", length);
@@ -556,6 +573,7 @@ void doMessenger()
         DHT_handlepacket(data, length, ip_port);
         LosslessUDP_handlepacket(data, length, ip_port);
         friendreq_handlepacket(data, length, ip_port);
+        LANdiscovery_handlepacket(data, length, ip_port);
 #endif
 
     }
@@ -564,6 +582,7 @@ void doMessenger()
     doNetCrypto();
     doInbound();
     doFriends();
+    LANdiscovery();
 }
 
 /* returns the size of the messenger data (for saving) */

core/Messenger.h

@@ -29,6 +29,7 @@
 #include "net_crypto.h"
 #include "DHT.h"
 #include "friend_requests.h"
+#include "LAN_discovery.h"
 
 #ifdef __cplusplus
 extern "C" {