TCP Checksum error stats in node_exporter

[vishnubraj]

Please add below stats in node_exporters.

node_netstat_Tcp_InCsumErrors node_netstat_Tcp_OutCsumErrors node_netstat_Udp_InCsumErrors node_netstat_Udp_OutCsumErrors

This will be very useful to find the DDos attacks.

@SuperQ FYI

[SuperQ]

Thanks, we have a number of normal In/Out Error counters. We were trying to keep the cardinality of the exporter down a bit.

For example, node_netstat_Tcp_InErrs should also include node_netstat_Tcp_InCsumErrors. It would be useful to verify that this is the case.

[discordianfish]

If you want them, you can adjust collector.netstat.fields accordantly