mirror of
https://github.com/coredns/coredns.git
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73 lines
1.4 KiB
Go
73 lines
1.4 KiB
Go
package debug
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import (
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"bytes"
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"fmt"
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"github.com/coredns/coredns/plugin/pkg/log"
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"github.com/miekg/dns"
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)
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// Hexdump converts the dns message m to a hex dump Wireshark can import.
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// See https://www.wireshark.org/docs/man-pages/text2pcap.html.
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// This output looks like this:
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//
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// 00000 dc bd 01 00 00 01 00 00 00 00 00 01 07 65 78 61
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// 000010 6d 70 6c 65 05 6c 6f 63 61 6c 00 00 01 00 01 00
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// 000020 00 29 10 00 00 00 80 00 00 00
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// 00002a
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//
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// Hexdump will use log.Debug to write the dump to the log, each line
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// is prefixed with 'debug: ' so the data can be easily extracted.
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//
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// msg will prefix the pcap dump.
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func Hexdump(m *dns.Msg, v ...interface{}) {
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if !log.D.Value() {
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return
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}
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buf, _ := m.Pack()
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if len(buf) == 0 {
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return
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}
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out := "\n" + string(hexdump(buf))
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v = append(v, out)
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log.Debug(v...)
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}
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// Hexdumpf dumps a DNS message as Hexdump, but allows a format string.
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func Hexdumpf(m *dns.Msg, format string, v ...interface{}) {
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if !log.D.Value() {
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return
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}
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buf, _ := m.Pack()
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if len(buf) == 0 {
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return
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}
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format += "\n%s"
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v = append(v, hexdump(buf))
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log.Debugf(format, v...)
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}
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func hexdump(data []byte) []byte {
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b := new(bytes.Buffer)
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newline := ""
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for i := 0; i < len(data); i++ {
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if i%16 == 0 {
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fmt.Fprintf(b, "%s%s%06x", newline, prefix, i)
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newline = "\n"
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}
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fmt.Fprintf(b, " %02x", data[i])
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}
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fmt.Fprintf(b, "\n%s%06x", prefix, len(data))
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return b.Bytes()
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}
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const prefix = "debug: "
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