Created UDP PDU. Done some documentation on TCP.

src/ip.cpp

@@ -126,8 +126,6 @@ void Tins::IP::set_option(uint8_t copied,
     option.type.number = number;
     uint8_t* buffer(0);
     if (data_size) {
-        /* data must be a valid pointer */
-        assert(data);
         buffer = new uint8_t[data_size];
         memcpy(buffer, data, data_size);
     }

src/tcp.cpp

@@ -37,6 +37,7 @@ Tins::TCP::TCP(uint16_t dport, uint16_t sport) : PDU(IPPROTO_TCP), _payload(0),
     _tcp.sport = Utils::net_to_host_s(sport);
     _tcp.doff = sizeof(tcphdr) / sizeof(uint32_t);
     _tcp.window = Utils::net_to_host_s(DEFAULT_WINDOW);
+    _tcp.check = 0;
 }
 
 Tins::TCP::~TCP() {
@@ -153,7 +154,8 @@ void Tins::TCP::write_serialization(uint8_t *buffer, uint32_t total_sz) {
     }
         
     memcpy(buffer, _payload, _payload_size);
-    _tcp.check = Utils::net_to_host_s(do_checksum(tcp_start + sizeof(tcphdr), buffer));
+    if(!_tcp.check)
+        _tcp.check = Utils::net_to_host_s(do_checksum(tcp_start + sizeof(tcphdr), buffer));
     memcpy(tcp_start, &_tcp, sizeof(tcphdr));
 }
 

src/udp.cpp

@@ -0,0 +1,14 @@
+#ifndef WIN32
+    #include <netinet/in.h>
+#endif
+#include "udp.h"
+
+Tins::UDP::UDP(uint16_t sport, uint16_t dport) : PDU(IPPROTO_UDP), _payload(0) {
+    _udp.sport = sport;
+    _udp.dport = dport;
+}
+
+void Tins::UDP::payload(uint8_t *new_payload, uint32_t new_payload_size) {
+    _payload = new_payload;
+    _udp.len = sizeof(udphdr) + new_payload_size;
+}