e6f81ebb31
Allow plugins to dump messages in text pcap to the log. The forward plugin does this when a reply does not much the query. If the debug plugin isn't loaded Hexdump and Hexdumpf are noop. Signed-off-by: Miek Gieben <miek@miek.nl>
48 lines
1.2 KiB
Markdown
48 lines
1.2 KiB
Markdown
# debug
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## Name
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*debug* - disables the automatic recovery upon a crash so that you'll get a nice stack trace.
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## Description
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Normally CoreDNS will recover from panics, using *debug* inhibits this. The main use of *debug* is
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to help testing. A side effect of using *debug* is that `log.Debug` and `log.Debugf` will be printed
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to standard output.
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Note that the *errors* plugin (if loaded) will also set a `recover` negating this setting.
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## Syntax
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~~~ txt
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debug
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~~~
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Some plugin will debug log DNS messages. This is done in the following format:
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~~~
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debug: 000000 00 0a 01 00 00 01 00 00 00 00 00 01 07 65 78 61
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debug: 000010 6d 70 6c 65 05 6c 6f 63 61 6c 00 00 01 00 01 00
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debug: 000020 00 29 10 00 00 00 80 00 00 00
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debug: 00002a
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~~~
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Using `text2pcap` (part of Wireshark) this can be converted back to binary, with the following
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command line: `text2pcap -i 17 -u 53,53`. Where 17 is the protocol (UDP) and 53 are the ports. These
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ports allow wireshark to detect these packets as DNS messages.
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Each plugin can decide to dump messages to aid in debugging.
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## Examples
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Disable the ability to recover from crashes and show debug logging:
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~~~ corefile
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. {
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debug
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}
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~~~
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## Also See
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https://www.wireshark.org/docs/man-pages/text2pcap.html.
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