private void BuildDHCPACK(PhysicalAddress chaddr, DhcpOption55 dhcpoption55, DhcpLeases dhcplease)
{
DhcpLeaseItem item = dhcplease.GetItem(chaddr);
// 必須
this.dhcpoptions_.Add(new DhcpOption53(DhcpPacket.MessageType.DHCPACK));
this.dhcpoptions_.Add(new DhcpOption(54, item.server_identifier_));
this.dhcpoptions_.Add(new DhcpOption(51, item.lease_time_));
// 任意
if (dhcpoption55.parameter_request_list_ != null)
{
foreach (byte b in dhcpoption55.parameter_request_list_)
{
switch (b)
{
case 1: this.dhcpoptions_.Add(new DhcpOption(1, item.subnet_mask_)); break;
case 3: this.dhcpoptions_.Add(new DhcpOption(3, item.router_)); break;
case 6: this.dhcpoptions_.Add(new DhcpOption(6, item.domain_name_server_)); break;
case 58: this.dhcpoptions_.Add(new DhcpOption(58, item.renewal_time_)); break;
case 59: this.dhcpoptions_.Add(new DhcpOption(59, item.rebinding_time_)); break;
default: break;
}
}
}
// 必須（最後必ず）
this.dhcpoptions_.Add(new DhcpOption(255));
}
// 解析
public static DhcpOption Parse(byte[] optionBytes, ref int pos)
{
// Pad Optionをスキップ
while ((pos < optionBytes.Length) && (optionBytes[pos] == CODE_PAD_OPTION))
{
pos++;
}
if (pos >= optionBytes.Length)
{
return(null);
}
// 生成
int code = optionBytes[pos++];
DhcpOption dhcpoption = null;
switch (code)
{
case 53: dhcpoption = new DhcpOption53(); break;
case 55: dhcpoption = new DhcpOption55(); break;
default: dhcpoption = new DhcpOption(); break;
}
dhcpoption._Code = code;
// End Option
if (dhcpoption._Code == CODE_END_OPTION)
{
dhcpoption._Len = 0;
dhcpoption._bytes = null;
return(dhcpoption);
}
dhcpoption._Len = optionBytes[pos++];
if (pos + dhcpoption._Len > optionBytes.Length)
{
return(null);
}
dhcpoption._bytes = optionBytes.Skip(pos).Take(dhcpoption._Len).ToArray();
pos += dhcpoption._Len;
// 解析
dhcpoption.Analyze();
return(dhcpoption);
}
// コンストラクタ
// 受信パケットの Parameter Request List ベース
public DhcpOptions(DhcpPacket.MessageType message_type, PhysicalAddress chaddr, DhcpOption55 dhcpoption55, DhcpLeases dhcplease)
: this()
{
if (message_type == DhcpPacket.MessageType.DHCPOFFER)
{
BuildDHCPOFFER(chaddr, dhcpoption55, dhcplease);
}
if (message_type == DhcpPacket.MessageType.DHCPACK)
{
BuildDHCPACK(chaddr, dhcpoption55, dhcplease);
}
}
