/*
 *  TAP-Windows -- A kernel driver to provide virtual tap
 *                 device functionality on Windows.
 *
 *  This code was inspired by the CIPE-Win32 driver by Damion K. Wilson.
 *
 *  This source code is Copyright (C) 2002-2014 OpenVPN Technologies, Inc.,
 *  and is released under the GPL version 2 (see below).
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program (see the file COPYING included with this
 *  distribution); if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#pragma once

#pragma pack(1)

//===================================================
// How many bad DHCPREQUESTs do we receive before we
// return a NAK?
//
// A bad DHCPREQUEST is defined to be one where the
// requestor doesn't know its IP address.
//===================================================

#define BAD_DHCPREQUEST_NAK_THRESHOLD 3

//==============================================
// Maximum number of DHCP options bytes supplied
//==============================================

#define DHCP_USER_SUPPLIED_OPTIONS_BUFFER_SIZE 256
#define DHCP_OPTIONS_BUFFER_SIZE 256

//===================================
// UDP port numbers of DHCP messages.
//===================================

#define BOOTPS_PORT 67
#define BOOTPC_PORT 68

//===========================
// The DHCP message structure
//===========================

typedef struct {
#define BOOTREQUEST 1
#define BOOTREPLY 2
  UCHAR op; /* message op */

  UCHAR htype; /* hardware address type (e.g. '1' = 10Mb Ethernet) */
  UCHAR hlen;  /* hardware address length (e.g. '6' for 10Mb Ethernet) */
  UCHAR hops;  /* client sets to 0, may be used by relay agents */
  ULONG xid;   /* transaction ID, chosen by client */
  USHORT secs; /* seconds since request process began, set by client */
  USHORT flags;
  ULONG ciaddr;     /* client IP address, client sets if known */
  ULONG yiaddr;     /* 'your' IP address -- server's response to client */
  ULONG siaddr;     /* server IP address */
  ULONG giaddr;     /* relay agent IP address */
  UCHAR chaddr[16]; /* client hardware address */
  UCHAR sname[64];  /* optional server host name */
  UCHAR file[128];  /* boot file name */
  ULONG magic;      /* must be 0x63825363 (network order) */
} DHCP;

typedef struct {
  ETH_HEADER eth;
  IPHDR ip;
  UDPHDR udp;
  DHCP dhcp;
} DHCPPre;

typedef struct {
  DHCPPre pre;
  UCHAR options[DHCP_OPTIONS_BUFFER_SIZE];
} DHCPFull;

typedef struct {
  unsigned int optlen;
  BOOLEAN overflow;
  DHCPFull msg;
} DHCPMsg;

//===================
// Macros for DHCPMSG
//===================

#define DHCPMSG_LEN_BASE(p) (sizeof(DHCPPre))
#define DHCPMSG_LEN_OPT(p) ((p)->optlen)
#define DHCPMSG_LEN_FULL(p) (DHCPMSG_LEN_BASE(p) + DHCPMSG_LEN_OPT(p))
#define DHCPMSG_BUF(p) ((UCHAR *)&(p)->msg)
#define DHCPMSG_OVERFLOW(p) ((p)->overflow)

//========================================
// structs to hold individual DHCP options
//========================================

typedef struct {
  UCHAR type;
} DHCPOPT0;

typedef struct {
  UCHAR type;
  UCHAR len;
  UCHAR data;
} DHCPOPT8;

typedef struct {
  UCHAR type;
  UCHAR len;
  ULONG data;
} DHCPOPT32;

#pragma pack()

//==================
// DHCP Option types
//==================

#define DHCP_MSG_TYPE 53    /* message type (u8) */
#define DHCP_PARM_REQ 55    /* parameter request list: c1 (u8), ... */
#define DHCP_CLIENT_ID 61   /* client ID: type (u8), i1 (u8), ... */
#define DHCP_IP 50          /* requested IP addr (u32) */
#define DHCP_NETMASK 1      /* subnet mask (u32) */
#define DHCP_LEASE_TIME 51  /* lease time sec (u32) */
#define DHCP_RENEW_TIME 58  /* renewal time sec (u32) */
#define DHCP_REBIND_TIME 59 /* rebind time sec (u32) */
#define DHCP_SERVER_ID 54   /* server ID: IP addr (u32) */
#define DHCP_PAD 0
#define DHCP_END 255

//====================
// DHCP Messages types
//====================

#define DHCPDISCOVER 1
#define DHCPOFFER 2
#define DHCPREQUEST 3
#define DHCPDECLINE 4
#define DHCPACK 5
#define DHCPNAK 6
#define DHCPRELEASE 7
#define DHCPINFORM 8

#if DBG

VOID DumpDHCP(const ETH_HEADER *eth, const IPHDR *ip, const UDPHDR *udp, const DHCP *dhcp,
              const int optlen);

#endif
