Added TCP pdu.

src/tcp.cpp

@@ -0,0 +1,93 @@
+#include <cstring>
+#include <cassert>
+#ifndef WIN32
+    #include <netinet/in.h>
+#endif
+#include "tcp.h"
+#include "utils.h"
+
+
+const uint16_t Tins::TCP::DEFAULT_WINDOW = 32678;
+
+Tins::TCP::TCP(uint16_t dport, uint16_t sport) : PDU(IPPROTO_TCP) {
+    std::memset(&_tcp, 0, sizeof(tcphdr));
+    _tcp.dport = Utils::net_to_host_s(dport);
+    _tcp.sport = Utils::net_to_host_s(sport);
+    _tcp.doff = sizeof(tcphdr) / sizeof(uint32_t);
+    _tcp.window = Utils::net_to_host_s(DEFAULT_WINDOW);
+}
+
+void Tins::TCP::dport(uint16_t new_dport) {
+    _tcp.dport = Utils::net_to_host_s(new_dport);
+}
+
+void Tins::TCP::sport(uint16_t new_sport) {
+    _tcp.sport = Utils::net_to_host_s(new_sport);
+}
+
+void Tins::TCP::seq(uint32_t new_seq) {
+    _tcp.seq = new_seq;
+}
+
+void Tins::TCP::ack_seq(uint32_t new_ack_seq) {
+    _tcp.ack_seq = new_ack_seq;
+}
+
+void Tins::TCP::window(uint16_t new_window) {
+    _tcp.window = new_window;
+}
+
+void Tins::TCP::check(uint16_t new_check) {
+    _tcp.check = new_check;
+}
+
+void Tins::TCP::urg_ptr(uint16_t new_urg_ptr) {
+    _tcp.urg_ptr = new_urg_ptr;
+}
+
+void Tins::TCP::set_flag(Flags tcp_flag, uint8_t value) {
+    switch(tcp_flag) {
+        case FIN:
+            _tcp.fin = value;
+            break;
+        case SYN:
+            _tcp.syn = value;
+            break;
+        case RST:
+            _tcp.rst = value;
+            break;
+        case PSH:
+            _tcp.psh = value;
+            break;
+        case ACK:
+            _tcp.ack = value;
+            break;
+        case URG:
+            _tcp.urg = value;
+            break;
+        case ECE:
+            _tcp.ece = value;
+            break;
+        case CWR:
+            _tcp.cwr = value;
+            break;
+    };
+}
+
+uint16_t Tins::TCP::do_checksum() const {
+    const uint8_t *ptr = (const uint8_t*)&_tcp, *end = (const uint8_t*)&_tcp + sizeof(tcphdr);
+    uint16_t checksum(0);
+    while(ptr < end)
+        checksum += *(ptr++);
+    return checksum;
+}
+
+uint32_t Tins::TCP::header_size() const {
+    return sizeof(tcphdr);
+}
+
+void Tins::TCP::write_serialization(uint8_t *buffer, uint32_t total_sz) {
+    assert(total_sz >= sizeof(tcphdr));
+    _tcp.check = Utils::net_to_host_s(do_checksum());
+    memcpy(buffer, &_tcp, sizeof(tcphdr));
+}