/// <summary>
/// Process request
/// </summary>
/// <param name="ip">IP</param>
/// <param name="id">ID</param>
/// <param name="seq">Sequence number</param>
/// <param name="data">Packet data</param>
/// <param name="length">Packet length</param>
private static unsafe void EchoReply(byte[] ip, ushort id, ushort seq, byte *data, int length)
{
NetPacketDesc *packet = NetPacket.Alloc();
ICMPHeader *hdr = (ICMPHeader *)(packet->buffer + packet->start);
hdr->Type = TYPE_ECHO_REPLY;
hdr->ID = id;
hdr->SeqNum = seq;
hdr->Code = 0;
hdr->CheckSum = 0;
packet->end += (short)sizeof(ICMPHeader);
Memory.Memcpy(packet->buffer + packet->end, data, length);
packet->end += (short)length;
hdr->CheckSum = NetworkTools.Checksum((byte *)(packet->buffer + packet->start), sizeof(ICMPHeader) + length);
IPV4.Send(packet, ip, 0x01);
NetPacket.Free(packet);
}
/// <summary>
/// ICMP packet handler
/// </summary>
/// <param name="sourceIp">Source IP</param>
/// <param name="buffer">Packet buffer</param>
/// <param name="size">Packet size</param>
private static unsafe void handler(byte[] sourceIp, byte *buffer, uint size)
{
ICMPHeader *hdr = (ICMPHeader *)buffer;
if (hdr->Type == TYPE_ECHO_REQUEST)
{
int length = (int)size - sizeof(ICMPHeader);
byte *data = buffer + sizeof(ICMPHeader);
EchoReply(sourceIp, hdr->ID, hdr->SeqNum, data, length);
}
}
