ZeroTierOne/windows/TapDriver/proto.h

/*
*  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) 2002-2010 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
*/

//============================================================
// MAC address, Ethernet header, and ARP
//============================================================

#pragma pack(1)

#define IP_HEADER_SIZE 20
#define IPV6_HEADER_SIZE 40

typedef unsigned char MACADDR [6];
typedef unsigned long IPADDR;
typedef unsigned char IPV6ADDR [16];

//-----------------
// Ethernet address
//-----------------

typedef struct {
	MACADDR addr;
} ETH_ADDR;

typedef struct {
	ETH_ADDR list[NIC_MAX_MCAST_LIST];
} MC_LIST;

//----------------
// Ethernet header
//----------------

typedef struct
{
	MACADDR dest;               /* destination eth addr	*/
	MACADDR src;                /* source ether addr	*/

# define ETH_P_IP   0x0800    /* IPv4 protocol */
# define ETH_P_IPV6 0x86DD    /* IPv6 protocol */
# define ETH_P_ARP  0x0806    /* ARP protocol */
	USHORT proto;               /* packet type ID field	*/
} ETH_HEADER, *PETH_HEADER;

//----------------
// ARP packet
//----------------

typedef struct
{
	MACADDR        m_MAC_Destination;        // Reverse these two
	MACADDR        m_MAC_Source;             // to answer ARP requests
	USHORT         m_Proto;                  // 0x0806

#   define MAC_ADDR_TYPE 0x0001
	USHORT         m_MAC_AddressType;        // 0x0001

	USHORT         m_PROTO_AddressType;      // 0x0800
	UCHAR          m_MAC_AddressSize;        // 0x06
	UCHAR          m_PROTO_AddressSize;      // 0x04

#   define ARP_REQUEST 0x0001
#   define ARP_REPLY   0x0002
	USHORT         m_ARP_Operation;          // 0x0001 for ARP request, 0x0002 for ARP reply

	MACADDR        m_ARP_MAC_Source;
	IPADDR         m_ARP_IP_Source;
	MACADDR        m_ARP_MAC_Destination;
	IPADDR         m_ARP_IP_Destination;
}
ARP_PACKET, *PARP_PACKET;

//----------
// IP Header
//----------

typedef struct {
# define IPH_GET_VER(v) (((v) >> 4) & 0x0F)
# define IPH_GET_LEN(v) (((v) & 0x0F) << 2)
	UCHAR    version_len;

	UCHAR    tos;
	USHORT   tot_len;
	USHORT   id;

# define IP_OFFMASK 0x1fff
	USHORT   frag_off;

	UCHAR    ttl;

# define IPPROTO_UDP  17  /* UDP protocol */
# define IPPROTO_TCP   6  /* TCP protocol */
# define IPPROTO_ICMP  1  /* ICMP protocol */
# define IPPROTO_IGMP  2  /* IGMP protocol */
	UCHAR    protocol;

	USHORT   check;
	ULONG    saddr;
	ULONG    daddr;
	/* The options start here. */
} IPHDR;

//-----------
// UDP header
//-----------

typedef struct {
	USHORT   source;
	USHORT   dest;
	USHORT   len;
	USHORT   check;
} UDPHDR;

//--------------------------
// TCP header, per RFC 793.
//--------------------------

typedef struct {
	USHORT      source;    /* source port */
	USHORT      dest;      /* destination port */
	ULONG       seq;       /* sequence number */
	ULONG       ack_seq;   /* acknowledgement number */

# define TCPH_GET_DOFF(d) (((d) & 0xF0) >> 2)
	UCHAR       doff_res;

# define TCPH_FIN_MASK (1<<0)
# define TCPH_SYN_MASK (1<<1)
# define TCPH_RST_MASK (1<<2)
# define TCPH_PSH_MASK (1<<3)
# define TCPH_ACK_MASK (1<<4)
# define TCPH_URG_MASK (1<<5)
# define TCPH_ECE_MASK (1<<6)
# define TCPH_CWR_MASK (1<<7)
	UCHAR       flags;

	USHORT      window;
	USHORT      check;
	USHORT      urg_ptr;
} TCPHDR;

#define	TCPOPT_EOL     0
#define	TCPOPT_NOP     1
#define	TCPOPT_MAXSEG  2
#define TCPOLEN_MAXSEG 4

//------------
// IPv6 Header
//------------

typedef struct {
	UCHAR    version_prio;
	UCHAR    flow_lbl[3];
	USHORT   payload_len;
# define IPPROTO_ICMPV6  0x3a  /* ICMP protocol v6 */
	UCHAR    nexthdr;
	UCHAR    hop_limit;
	IPV6ADDR saddr;
	IPV6ADDR daddr;
} IPV6HDR;

//--------------------------------------------
// IPCMPv6 NS/NA Packets (RFC4443 and RFC4861)
//--------------------------------------------

// Neighbor Solictiation - RFC 4861, 4.3
// (this is just the ICMPv6 part of the packet)
typedef struct {
	UCHAR    type;
# define ICMPV6_TYPE_NS	135		// neighbour solicitation
	UCHAR    code;
# define ICMPV6_CODE_0	0		// no specific sub-code for NS/NA
	USHORT   checksum;
	ULONG    reserved;
	IPV6ADDR target_addr;
} ICMPV6_NS;

// Neighbor Advertisement - RFC 4861, 4.4 + 4.6/4.6.1
// (this is just the ICMPv6 payload)
typedef struct {
	UCHAR    type;
# define ICMPV6_TYPE_NA	136		// neighbour advertisement
	UCHAR    code;
# define ICMPV6_CODE_0	0		// no specific sub-code for NS/NA
	USHORT   checksum;
	UCHAR    rso_bits;			// Router(0), Solicited(2), Ovrrd(4)
	UCHAR	   reserved[3];
	IPV6ADDR target_addr;
	// always include "Target Link-layer Address" option (RFC 4861 4.6.1)
	UCHAR    opt_type;
#define ICMPV6_OPTION_TLLA 2
	UCHAR    opt_length;
#define ICMPV6_LENGTH_TLLA 1		// multiplied by 8 -> 1 = 8 bytes
	MACADDR  target_macaddr;
} ICMPV6_NA;

// this is the complete packet with Ethernet and IPv6 headers
typedef struct {
	ETH_HEADER eth;
	IPV6HDR    ipv6;
	ICMPV6_NA  icmpv6;
} ICMPV6_NA_PKT;

#pragma pack()