[Packetbeat] pcap sniffer hangs on exit

[andrewkroh]

Packetbeat is not exiting cleanly on Linux with the pcap sniffer. There is no timeout signal for the pcap reader so if no packets are received to unblock the read loop it will hang forever.

Perhaps we need to update gopacket (like for google/gopacket#256).

This was detected by beats-tester when we noticed that the logs from Packetbeat were incomplete (missing "packetbeat stopped.").

For confirmed bugs, please report:

• Version: 6.2.2
• Operating System: Linux (observed on ubuntu1604, awslinux, opensuse)
• Steps to Reproduce:
  • Configure Packetbeat with the pcap sniffer on Linux.
  • Use a config where no Packets are being received.
  • Send Ctrl+C

packetbeat.interfaces.device: any

packetbeat.protocols:
- type: http
  ports: [11180] # Some port where there's no traffic.

output.file:
  path: '${path.logs}'
  filename: output.json

logging:
  level: info
  json: true
  files:
    name: packetbeat.json

[andrewkroh]

I'm also seeing the same behavior with af_packet.

[andrewkroh]

This is currently causing beats-tester to fail because it verifies that the beat shuts down properly by checking the log file.

[adriansr]

I've found out those to be two separate issues.

For af_packet, timeout wasn't being handled correctly at all.
For pcap, it is a well-known problem with libpcap 1.8.0+ which supports TPACKET_V3 to capture packets.