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pcapUtils.go
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/
pcapUtils.go
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/*
* 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 collector
import (
"bufio"
"fmt"
"os"
"path/filepath"
"github.com/dreadl0ck/netcap/encoder"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcapgo"
)
// close errors.pcap and unknown.pcap
func (c *Collector) closePcapFiles() {
// unknown.pcap
err := c.unkownPcapWriterBuffered.Flush()
if err != nil {
panic(err)
}
i, err := c.unknownPcapFile.Stat()
if err != nil {
panic(err)
}
// if file is empty, or a pcap with just the header
if i.Size() == 0 || i.Size() == 24 {
//println("removing", fd.Name())
err := os.Remove(c.unknownPcapFile.Name())
if err != nil {
fmt.Println("failed to remove file:", c.unknownPcapFile.Name(), err)
}
}
var (
errSync = c.unknownPcapFile.Sync()
errClose = c.unknownPcapFile.Close()
)
if errSync != nil || errClose != nil {
fmt.Println("error while closing", i.Name(), "errSync", errSync, "errClose", errClose)
}
// errors.pcap
err = c.errorsPcapWriterBuffered.Flush()
if err != nil {
panic(err)
}
i, err = c.errorsPcapFile.Stat()
if err != nil {
panic(err)
}
// if file is empty, or a pcap with just the header
if i.Size() == 0 || i.Size() == 24 {
//println("removing", fd.Name())
err := os.Remove(c.errorsPcapFile.Name())
if err != nil {
fmt.Println("failed to remove file:", c.errorsPcapFile.Name(), err)
}
}
errSync = c.errorsPcapFile.Sync()
errClose = c.errorsPcapFile.Close()
if errSync != nil || errClose != nil {
fmt.Println("error while closing", i.Name(), "errSync", errSync, "errClose", errClose)
}
}
// create unknown.pcap file for packets with unknown layers
func (c *Collector) createUnknownPcap() {
var err error
// Open output pcap file and write header
c.unknownPcapFile, err = os.Create(filepath.Join(c.config.EncoderConfig.Out, "unknown.pcap"))
if err != nil {
panic(err)
}
c.unkownPcapWriterBuffered = bufio.NewWriterSize(c.unknownPcapFile, encoder.BlockSize)
pcapWriter := pcapgo.NewWriter(c.unkownPcapWriterBuffered)
// set global pcap writer
c.unkownPcapWriterAtomic = NewAtomicPcapGoWriter(pcapWriter)
pcapWriter.WriteFileHeader(1024, layers.LinkTypeEthernet)
}
// create errors.pcap file for errors
func (c *Collector) createErrorsPcap() {
var err error
// Open output pcap file and write header
c.errorsPcapFile, err = os.Create(filepath.Join(c.config.EncoderConfig.Out, "errors.pcap"))
if err != nil {
panic(err)
}
c.errorsPcapWriterBuffered = bufio.NewWriterSize(c.errorsPcapFile, encoder.BlockSize)
pcapWriter := pcapgo.NewWriter(c.errorsPcapWriterBuffered)
// set global pcap writer
c.errorsPcapWriterAtomic = NewAtomicPcapGoWriter(pcapWriter)
pcapWriter.WriteFileHeader(1024, layers.LinkTypeEthernet)
}
// write a packet to the unknown.pcap file
// if WriteUnknownPackets is set in the config
func (c *Collector) writePacketToUnknownPcap(p gopacket.Packet) {
if c.config.WriteUnknownPackets {
err := c.unkownPcapWriterAtomic.WritePacket(p.Metadata().CaptureInfo, p.Data())
if err != nil {
panic(err)
}
}
}
// logPacketError handles an error when decoding a packet
func (c *Collector) logPacketError(p gopacket.Packet, err string) {
// increment errorMap stats
c.errorMap.Inc(err)
// write entry to errors.log
c.errorLogFile.WriteString(p.Metadata().Timestamp.String() + "\nError: " + err + "\nPacket:\n" + p.Dump() + "\n")
// write packet to errors.pcap
c.writePacketToErrorsPcap(p)
}
// write a packet to the errors.pcap file
func (c *Collector) writePacketToErrorsPcap(p gopacket.Packet) {
err := c.errorsPcapWriterAtomic.WritePacket(p.Metadata().CaptureInfo, p.Data())
if err != nil {
panic(err)
}
}