detect PCAP write errors

Without this check the code continues to write into output file even if the device is hopelessly ENOSPC, potentially wasting lots time and silently corrupting the output.

The magic constant 1 check per 10 000 output packets causes 0.4 % overhead in my tests where whole input is cached and write goes to /dev/null.

This is not perfect - errors from the underlying close() operation are not reported. Unfortunately this is a limitation in pcap interface and we cannot do anything about it.

added 9 commits

• 28f6a605...165bd5e6 - 3 commits from branch master
• 8b8517a6 - extract-clients: detect write errors
• 3ed2d79f - cut-pcap: detect write errors
• d738b8ba - limit-clients: detect write errors
• 186b2dfa - limit-clients: fix log prefix
• 3316fe6a - filter-dnsq: remove obsolete null output
• 587722e9 - filter-dnsq: detect write errors

Compare with previous version

marked this merge request as ready

Seems like a nice addition, thanks! :)

approved this merge request

merged

mentioned in commit dd89573f