src/patches/dnsmasq/0056-New-version-of-contrib-reverse-dns.patch

   1 From 4c960fa90a975d20f75a1ecabd217247f1922c8f Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Wed, 4 Mar 2015 20:32:26 +0000
   4 Subject: [PATCH 56/87] New version of contrib/reverse-dns
   5
   6 ---
   7  contrib/reverse-dns/README             |  22 +++---
   8  contrib/reverse-dns/reverse_replace.sh | 131 ++++++++++++++++++++++++++++-----
   9  2 files changed, 125 insertions(+), 28 deletions(-)
  10
  11 diff --git a/contrib/reverse-dns/README b/contrib/reverse-dns/README
  12 index f87eb77c4c22..2ec4df1f957e 100644
  13 --- a/contrib/reverse-dns/README
  14 +++ b/contrib/reverse-dns/README
  15 @@ -1,18 +1,18 @@
  16 -Hi.
  17 +The script reads stdin and replaces all IP addresses with names before
  18 +outputting it again. IPs from private networks are reverse looked  up
  19 +via dns. Other IP adresses are searched for in the dnsmasq query log.
  20 +This gives names (CNAMEs if I understand DNS correctly) that are closer
  21 +to the name the client originally asked for then the names obtained by
  22 +reverse lookup. Just run
  23
  24 -To translate my routers netstat-nat output into names that actually talk
  25 -to me I have started writing to simple shell scripts. They require
  26 +netstat -n -4 | ./reverse_replace.sh
  27 +
  28 +to see what it does. It needs
  29
  30  log-queries
  31  log-facility=/var/log/dnsmasq.log
  32
  33 -to be set. With
  34 -
  35 -netstat-nat -n -4 | reverse_replace.sh
  36 -
  37 -I get retranslated output.
  38 -
  39 -Sincerely,
  40 -Joachim
  41 +in the dnsmasq configuration.
  42
  43 +The script runs on debian (with ash installed) and on busybox.
  44
  45 diff --git a/contrib/reverse-dns/reverse_replace.sh b/contrib/reverse-dns/reverse_replace.sh
  46 index a11c164b7f19..5b4aebd71456 100644
  47 --- a/contrib/reverse-dns/reverse_replace.sh
  48 +++ b/contrib/reverse-dns/reverse_replace.sh
  49 @@ -1,28 +1,125 @@
  50 -#!/bin/bash
  51 -# $Id: reverse_replace.sh 4 2015-02-17 20:14:59Z jo $
  52 +#!/bin/ash
  53 +# $Id: reverse_replace.sh 18 2015-03-01 16:12:35Z jo $
  54  #
  55  # Usage e.g.: netstat -n -4 | reverse_replace.sh
  56  # Parses stdin for IP4 addresses and replaces them
  57 -# with names retrieved by reverse_dns.sh
  58 +# with names retrieved by parsing the dnsmasq log.
  59 +# This currently only gives CNAMEs. But these
  60 +# usually tell ou more than the mones from reverse
  61 +# lookups.
  62 +#
  63 +# This has been tested on debian and asuswrt. Plese
  64 +# report successful tests on other platforms.
  65 +#
  66 +# Author: Joachim Zobel <jz-2014@heute-morgen.de>
  67 +# License: Consider this MIT style licensed. You can
  68 +#   do as you ike, but you must not remove my name.
  69  #
  70
  71 -DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
  72 -DNS=$DIR/reverse_dns.sh
  73 +LOG=/var/log/dnsmasq.log
  74 +MAX_LINES=15000
  75
  76 -# sed regex
  77 +# sed regex do match IPs
  78  IP_regex='[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}'
  79 +# private IP ranges
  80 +IP_private='\(^127\.\)\|\(^192\.168\.\)\|\(^10\.\)\|\(^172\.1[6-9]\.\)\|\(^172\.2[0-9]\.\)\|\(^172\.3[0-1]\.\)'
  81
  82 -while read LINE; do
  83 -  if grep --quiet $IP_regex <<< "$LINE"; then
  84 -    IPs=`sed "s#.*\b\($IP_regex\)\b.*#\1 #g" <<< "$LINE"`
  85 -    IPs=($IPs)
  86 -    for IP in "${IPs[@]}"
  87 -    do
  88 -      NAME=`$DNS $IP`
  89 -      # echo "$NAME is $IP";
  90 -      LINE="${LINE/$IP/$NAME}"
  91 -    done
  92 +#######################################################################
  93 +# Find Commands
  94 +
  95 +HOST=nslookup
  96 +if type host > /dev/null 2>&1; then
  97 +  # echo "No need for nslookup, host is there"
  98 +  HOST=host
  99 +fi
 100 +
 101 +#######################################################################
 102 +# Functions
 103 +
 104 +# Use shell variables for an (IP) lookup table
 105 +create_lookup_table()
 106 +{
 107 +  # Parse log into lookup table
 108 +  local CMDS="$( tail -"$MAX_LINES" "$LOG" | \
 109 +    grep " is $IP_regex" | \
 110 +    sed "s#.* \([^ ]*\) is \($IP_regex\).*#set_val \2 \1;#" )"
 111 +
 112 +  local IFS='
 113 +'
 114 +  for CMD in $CMDS
 115 +  do
 116 +    eval $CMD
 117 +  done
 118 +}
 119 +
 120 +set_val()
 121 +{
 122 +  local _IP=$(echo $1 | tr . _)
 123 +  local KEY="__IP__$_IP"
 124 +  eval "$KEY"=$2
 125 +}
 126 +
 127 +get_val()
 128 +{
 129 +  local _IP=$(echo $1 | tr . _)
 130 +  local KEY="__IP__$_IP"
 131 +  eval echo -n '${'"$KEY"'}'
 132 +}
 133 +
 134 +dns_lookup()
 135 +{
 136 +  local IP=$1
 137 +
 138 +  local RTN="$($HOST $IP | \
 139 +        sed 's#\s\+#\n#g' | \
 140 +        grep -v '^$' | \
 141 +        tail -1 | tr -d '\n' | \
 142 +        sed 's#\.$##')"
 143 +  if echo $RTN | grep -q NXDOMAIN; then
 144 +    echo -n $IP
 145 +  else
 146 +    echo -n "$RTN"
 147 +  fi
 148 +}
 149 +
 150 +reverse_dns()
 151 +{
 152 +  local IP=$1
 153 +
 154 +  # Skip if it is not an IP
 155 +  if ! echo $IP | grep -q "^$IP_regex$"; then
 156 +    echo -n $IP
 157 +    return
 158 +  fi
 159 +
 160 +  # Do a dns lookup, if it is a local IP
 161 +  if echo $IP | grep -q $IP_private; then
 162 +    dns_lookup $IP
 163 +    return
 164    fi
 165 +
 166 +  local NAME="$(get_val $IP)"
 167 +
 168 +  if [ -z "$NAME" ]; then
 169 +    echo -n $IP
 170 +  else
 171 +    echo -n $NAME
 172 +  fi
 173 +}
 174 +
 175 +#######################################################################
 176 +# Main
 177 +create_lookup_table
 178 +
 179 +while read LINE; do
 180 +  for IP in $(echo "$LINE" | \
 181 +              sed "s#\b\($IP_regex\)\b#\n\1\n#g" | \
 182 +              grep $IP_regex)
 183 +  do
 184 +    NAME=`reverse_dns $IP `
 185 +    # echo "$NAME $IP"
 186 +    LINE=`echo "$LINE" | sed "s#$IP#$NAME#" `
 187 +  done
 188    echo $LINE
 189 -done < /dev/stdin
 190 +done
 191
 192 --
 193 2.1.0
 194