tcp.go

/*
 * NETCAP - Traffic Analysis Framework
 * Copyright (c) 2017 Philipp Mieden <dreadl0ck [at] protonmail [dot] ch>
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

package encoder

import (
	"github.com/dreadl0ck/netcap/types"
	"github.com/golang/protobuf/proto"
	"github.com/google/gopacket"
	"github.com/google/gopacket/layers"
)

var tcpEncoder = CreateLayerEncoder(types.Type_NC_TCP, layers.LayerTypeTCP, func(layer gopacket.Layer, timestamp string) proto.Message {
	if tcp, ok := layer.(*layers.TCP); ok {
		var opts []*types.TCPOption
		for _, o := range tcp.Options {
			opts = append(opts, &types.TCPOption{
				OptionData:   o.OptionData,
				OptionLength: int32(o.OptionLength),
				OptionType:   int32(o.OptionType),
			})
		}
		return &types.TCP{
			Timestamp:      timestamp,
			SrcPort:        int32(tcp.SrcPort),
			DstPort:        int32(tcp.DstPort),
			SeqNum:         uint32(tcp.Seq),
			AckNum:         uint32(tcp.Ack),
			DataOffset:     int32(tcp.DataOffset),
			FIN:            bool(tcp.FIN),
			SYN:            bool(tcp.SYN),
			RST:            bool(tcp.RST),
			PSH:            bool(tcp.PSH),
			ACK:            bool(tcp.ACK),
			URG:            bool(tcp.URG),
			ECE:            bool(tcp.ECE),
			CWR:            bool(tcp.CWR),
			NS:             bool(tcp.NS),
			Window:         int32(tcp.Window),
			Checksum:       int32(tcp.Checksum),
			Urgent:         int32(tcp.Urgent),
			Padding:        tcp.Padding,
			Options:        opts,
			PayloadEntropy: Entropy(tcp.Payload),
			PayloadSize:    int32(len(tcp.Payload)),
		}
	}
	return nil
})