Added DHCP class. It's now working yet.

src/dhcp.cpp

@@ -0,0 +1,52 @@
+#include <cstring>
+#include <cassert>
+#include <iostream> //borrame
+#include "utils.h"
+#include "dhcp.h"
+
+const uint32_t Tins::DHCP::MAX_DHCP_SIZE = 312;
+
+/* Magic cookie: uint32_t.
+ * end of options: 1 byte. */
+Tins::DHCP::DHCP() : _size(sizeof(uint32_t) + 1) {
+    opcode(BOOTREQUEST);
+    htype(1); //ethernet
+    hlen(6);
+}
+
+Tins::DHCP::DHCPOption::DHCPOption(uint8_t opt, uint8_t len, uint8_t *val) : option(opt), length(len) {
+    value = new uint8_t[len];
+    std::memcpy(value, val, len);
+}
+
+bool Tins::DHCP::add_option(Options opt, uint8_t len, uint8_t *val) {
+    uint32_t opt_size = len + (sizeof(uint8_t) << 1);
+    if(_size + opt_size > MAX_DHCP_SIZE)
+        return false;
+    _options.push_back(DHCPOption((uint8_t)opt, len, val));
+    _size += opt_size;
+    return true;
+}
+
+void Tins::DHCP::add_type_option(Flags type) {
+    add_option(DHCP_MESSAGE_TYPE, 1, (uint8_t*)&type);
+}
+
+uint32_t Tins::DHCP::header_size() const {
+    return BootP::header_size() - vend_size() + _size;
+}
+
+void Tins::DHCP::write_serialization(uint8_t *buffer, uint32_t total_sz, const PDU *parent) {
+    assert(total_sz >= header_size());
+    uint8_t *result = new uint8_t[_size], *ptr = result + sizeof(uint32_t);
+    *((uint32_t*)result) = Utils::net_to_host_l(0x63825363);
+    for(std::list<DHCPOption>::const_iterator it = _options.begin(); it != _options.end(); ++it) {
+        *(ptr++) = it->option;
+        *(ptr++) = it->length;
+        std::memcpy(ptr++, it->value, it->length);
+    }
+    result[_size-1] = END;
+    vend(result, _size);
+    BootP::write_serialization(buffer, total_sz, parent);
+}
+