const (
	TYPE_IP   = 0x0800
	TYPE_ARP  = 0x0806
	TYPE_IP6  = 0x86DD
	TYPE_VLAN = 0x8100

	IP_ICMP = 1
	IP_INIP = 4
	IP_TCP  = 6
	IP_UDP  = 17
)

const (
	ERRBUF_SIZE = 256

	// According to pcap-linktype(7).
	LINKTYPE_NULL             = 0
	LINKTYPE_ETHERNET         = 1
	LINKTYPE_TOKEN_RING       = 6
	LINKTYPE_ARCNET           = 7
	LINKTYPE_SLIP             = 8
	LINKTYPE_PPP              = 9
	LINKTYPE_FDDI             = 10
	LINKTYPE_ATM_RFC1483      = 100
	LINKTYPE_RAW              = 101
	LINKTYPE_PPP_HDLC         = 50
	LINKTYPE_PPP_ETHER        = 51
	LINKTYPE_C_HDLC           = 104
	LINKTYPE_IEEE802_11       = 105
	LINKTYPE_FRELAY           = 107
	LINKTYPE_LOOP             = 108
	LINKTYPE_LINUX_SLL        = 113
	LINKTYPE_LTALK            = 104
	LINKTYPE_PFLOG            = 117
	LINKTYPE_PRISM_HEADER     = 119
	LINKTYPE_IP_OVER_FC       = 122
	LINKTYPE_SUNATM           = 123
	LINKTYPE_IEEE802_11_RADIO = 127
	LINKTYPE_ARCNET_LINUX     = 129
	LINKTYPE_LINUX_IRDA       = 144
	LINKTYPE_LINUX_LAPD       = 177
)

const (
	TCP_FIN = 1 << iota
	TCP_SYN
	TCP_RST
	TCP_PSH
	TCP_ACK
	TCP_URG
	TCP_ECE
	TCP_CWR
	TCP_NS
)

type Arphdr struct {
	Addrtype          uint16
	Protocol          uint16
	HwAddressSize     uint8
	ProtAddressSize   uint8
	Operation         uint16
	SourceHwAddress   []byte
	SourceProtAddress []byte
	DestHwAddress     []byte
	DestProtAddress   []byte
}

type FileHeader struct {
	MagicNumber  uint32
	VersionMajor uint16
	VersionMinor uint16
	TimeZone     int32
	SigFigs      uint32
	SnapLen      uint32
	Network      uint32
}

type IFAddress struct {
	IP      net.IP
	Netmask net.IPMask
}

type Icmphdr struct {
	Type     uint8
	Code     uint8
	Checksum uint16
	Id       uint16
	Seq      uint16
	Data     []byte
}

type Interface struct {
	Name        string
	Description string
	Addresses   []IFAddress
}

type Ip6hdr struct {
	// http://www.networksorcery.com/enp/protocol/ipv6.htm
	Version      uint8  // 4 bits
	TrafficClass uint8  // 8 bits
	FlowLabel    uint32 // 20 bits
	Length       uint16 // 16 bits
	NextHeader   uint8  // 8 bits, same as Protocol in Iphdr
	HopLimit     uint8  // 8 bits
	SrcIp        []byte // 16 bytes
	DestIp       []byte // 16 bytes
}

type Iphdr struct {
	Version    uint8
	Ihl        uint8
	Tos        uint8
	Length     uint16
	Id         uint16
	Flags      uint8
	FragOffset uint16
	Ttl        uint8
	Protocol   uint8
	Checksum   uint16
	SrcIp      []byte
	DestIp     []byte
}

type Packet struct {
	Time   time.Time // packet send/receive time
	Caplen uint32    // bytes stored in the file (caplen <= len)
	Len    uint32    // bytes sent/received
	Data   []byte    // packet data

	Type    int // protocol type, see LINKTYPE_*
	DestMac uint64
	SrcMac  uint64

	Headers []interface{} // decoded headers, in order
	Payload []byte        // remaining non-header bytes

	IP  *Iphdr  // IP header (for IP packets, after decoding)
	TCP *Tcphdr // TCP header (for TCP packets, after decoding)
	UDP *Udphdr // UDP header (for UDP packets after decoding)
}

type PacketTime struct {
	Sec  int32
	Usec int32
}

type Pcap struct {
	// contains filtered or unexported fields
}

type Reader struct {
	Header FileHeader
	// contains filtered or unexported fields
}

type Stat struct {
	PacketsReceived  uint32
	PacketsDropped   uint32
	PacketsIfDropped uint32
}

type Tcphdr struct {
	SrcPort    uint16
	DestPort   uint16
	Seq        uint32
	Ack        uint32
	DataOffset uint8
	Flags      uint16
	Window     uint16
	Checksum   uint16
	Urgent     uint16
	Data       []byte
}

type Udphdr struct {
	SrcPort  uint16
	DestPort uint16
	Length   uint16
	Checksum uint16
}

type Vlanhdr struct {
	Priority       byte
	DropEligible   bool
	VlanIdentifier int
	Type           int // Not actually part of the vlan header, but the type of the actual packet
}

type Writer struct {
	// contains filtered or unexported fields
}