/// <summary>
/// Add DHCP header in packet
/// </summary>
/// <param name="packet"></param>
/// <param name="xid"></param>
/// <param name="clientIP"></param>
/// <param name="messageType"></param>
private static unsafe void addHeader(NetPacketDesc *packet, uint xid, byte[] clientIP, byte messageType)
{
DHCPBootstrapHeader *header = (DHCPBootstrapHeader *)(packet->buffer + packet->start);
Memory.Memclear(header, sizeof(DHCPBootstrapHeader));
header->Opcode = 1; // REQUEST
header->HardwareType = HARDTYPE_ETH; // Ethernet
header->HardwareAddressLength = 6; // IPV4
header->Hops = 0;
header->TransactionID = Byte.ReverseBytes(xid);
header->SecondsElapsed = 0; // NULLLLL
header->BootpFlags = 0; // NONNNN
for (int i = 0; i < 4; i++)
{
header->ClientIP[i] = clientIP[i];
}
Network.GetMac(header->ClientMac);
packet->end += (short)sizeof(DHCPBootstrapHeader);
/**
* Default options
*/
byte *opt = packet->buffer + packet->end;
uint *topt = (uint *)opt;
*topt = Byte.ReverseBytes(MAGISCH_KOEKJE); // 4 bytes!
opt += 4; // Another FOUR!
/**
* Set message type
*/
*opt++ = OPT_DHCP_MESSAGE_TYPE; // OPT_DHCP_MESSAGE_TYPE
*opt++ = 1;
*opt++ = messageType;
packet->end += 7;
}
/// <summary>
/// Prints the DHCP bootstrap header
/// </summary>
/// <param name="header">The header</param>
private static unsafe void Debug(DHCPBootstrapHeader *header)
{
Console.WriteLine("================================\nDHCP DEBUG\n==========================");
Console.Write("DHCP: opcode = ");
Console.WriteHex(header->Opcode);
Console.Write(", htype = ");
Console.WriteHex(header->HardwareType);
Console.Write(", hlen = ");
Console.WriteHex(header->HardwareAddressLength);
Console.Write(", hops = ");
Console.WriteHex(header->Hops);
Console.Write(", xid = ");
Console.WriteHex(Byte.ReverseBytes(header->TransactionID));
Console.Write(", secs = ");
Console.WriteNum(Byte.ReverseBytes(header->SecondsElapsed));
Console.Write(", flags = ");
Console.WriteHex(Byte.ReverseBytes(header->BootpFlags));
Console.WriteLine("");
}
/// <summary>
/// Perform a DHCP request
/// </summary>
/// <param name="buffer">Old packet</param>
private static unsafe void request(byte *buffer, byte[] ip)
{
DHCPBootstrapHeader *header = (DHCPBootstrapHeader *)buffer;
NetPacketDesc * packet = NetPacket.Alloc();
byte[] tmp = new byte[4];
/**
* Write header to packet
*/
addHeader(packet, Byte.ReverseBytes(header->TransactionID), tmp, DHCP_REQUEST);
/**
* Write our received ip
*/
byte *buf = packet->buffer + packet->end;
*buf++ = OPT_REQ_IP;
*buf++ = 4; // IP is 4 bytes
for (int i = 0; i < 4; i++)
{
*buf++ = header->YourClientIP[i];
}
packet->end += 6;
string hostname = Network.GetHostName();
int hostnameLength = hostname.Length;
if (hostnameLength > 0xFF)
{
hostnameLength = 0xFF;
}
/**
* Write our hostname
*/
buf = packet->buffer + packet->end;
*buf++ = OPT_HOSTNAME;
*buf++ = (byte)hostnameLength;
for (int i = 0; i < hostnameLength; i++)
{
*buf++ = (byte)hostname[i];
}
packet->end += 10;
buf = packet->buffer + packet->end;
*buf++ = OPT_SERVER_ID;
*buf++ = 4;
for (int i = 0; i < 4; i++)
{
*buf++ = ip[i];
}
packet->end += 6;
/**
* Choose what we want to receive
*/
buf = packet->buffer + packet->end;
*buf++ = OPT_PARAMETER_REQUEST; // OPT_PARAMETER_REQUEST
*buf++ = 4; // Length of 4 :)
*buf++ = OPT_SUBNET; // SUBNET
*buf++ = OPT_ROUTER; // ROUTER
*buf++ = OPT_NTP; // NTP
*buf++ = OPT_DNS; // DNS
*buf++ = OPT_END; // And then
packet->end += 14;
for (int i = 0; i < 4; i++)
{
tmp[i] = 0xFF;
}
UDP.Send(packet, tmp, 68, 67);
NetPacket.Free(packet);
Heap.Free(tmp);
}
/// <summary>
/// Handle ack
/// </summary>
/// <param name="buffer">The buffer</param>
/// <param name="maxsize">Maximum size</param>
private static unsafe void handleAck(byte *buffer, uint maxsize)
{
DHCPBootstrapHeader *header = (DHCPBootstrapHeader *)buffer;
/**
* Do not send us anymore!
*/
if (header->YourClientIP[0] == 0x00)
{
return;
}
for (int i = 0; i < 4; i++)
{
Network.Settings->IP[i] = header->YourClientIP[i];
}
int offset = sizeof(DHCPBootstrapHeader) + 4;
/**
* Loop through options
*/
while (offset < maxsize && buffer[offset] != OPT_END)
{
byte type = buffer[offset];
switch (type)
{
case OPT_SERVER_ID:
for (int i = 0; i < 4; i++)
{
Network.Settings->ServerID[i] = buffer[offset + 2 + i];
}
break;
case OPT_ROUTER:
for (int i = 0; i < 4; i++)
{
Network.Settings->Gateway[i] = buffer[offset + 2 + i];
}
Route.SetGateway(Util.PtrToArray(Network.Settings->Gateway));
break;
case OPT_SUBNET:
for (int i = 0; i < 4; i++)
{
Network.Settings->Subnet[i] = buffer[offset + 2 + i];
}
break;
case OPT_DNS:
{
byte len = buffer[offset + 1];
for (int i = 0; i < 4; i++)
{
Network.Settings->DNS1[i] = buffer[offset + 2 + i];
}
// More then 1 DNS?
if (len > 4)
{
for (int i = 0; i < 4; i++)
{
Network.Settings->DNS2[i] = buffer[offset + 4 + i];
}
}
break;
}
}
offset += buffer[offset + 1] + 2;
}
Console.Write("[DHCP] dhcp assigned us ip: ");
for (int i = 0; i < 3; i++)
{
Console.WriteNum(Network.Settings->IP[i]);
Console.Write('.');
}
Console.WriteNum(Network.Settings->IP[3]);
Console.Write('\n');
}
