proxy.sh

   1 #! /usr/bin/env bash
   2 # source: proxy.sh
   3 # Copyright Gerhard Rieger and contributors (see file CHANGES)
   4 # Published under the GNU General Public License V.2, see file COPYING
   5
   6 # perform primitive simulation of a proxy server.
   7 # accepts and answers correct HTTP CONNECT requests on stdio, and tries to
   8 # establish the connection to the given server.
   9 # it is required for socats test.sh
  10 # for TCP, use this script like:
  11 # socat TCP-L:8080,reuseaddr,fork EXEC:"proxy.sh",nofork
  12
  13 # 20130622  GR allow hostnames, not only IP addresses
  14
  15 if [ -z "$SOCAT" ]; then
  16     if type socat >/dev/null 2>&1; then
  17         SOCAT=socat
  18     else
  19         SOCAT="./socat"
  20     fi
  21 fi
  22
  23 if   [ $(echo "x\c") = "x" ]; then E=""
  24 elif [ $(echo -e "x\c") = "x" ]; then E="-e"
  25 else
  26     echo "cannot suppress trailing newline on echo" >&2
  27     exit 1
  28 fi
  29 ECHO="echo $E"
  30 CR=$($ECHO "\r")
  31 #echo "CR=$($ECHO "$CR\c" |od -c)" >&2
  32
  33 case `uname` in
  34 HP-UX|OSF1)
  35     # their cats are too stupid to work with unix domain sockets
  36     CAT="$SOCAT -u stdin stdout"
  37     ;;
  38 *)
  39     CAT=cat
  40     ;;
  41 esac
  42
  43 SPACES=" "
  44 while [ -n "$1" ]; do
  45     case "$1" in
  46     -w) n="$2"; while [ "$n" -gt 0 ]; do SPACES="$SPACES "; n=$((n-1)); done
  47         shift ;;
  48     #-s) STAT="$2"; shift ;;
  49     esac
  50     shift
  51 done
  52
  53 badrequest () {
  54     $ECHO "HTTP/1.0${SPACES}500 Bad Request$CR"
  55     $ECHO "$CR"
  56 }
  57
  58 # read and parse HTTP request
  59 read m a h
  60 #echo "\"$m\" \"$a\" \"$h\"" >&2
  61 if [ "$m" != 'CONNECT' ]; then
  62     badrequest; exit 1
  63 fi
  64 if [[ "$a" == [0-9]+\.[0-9]+\.[0-9]+\.[0-9]+:[0-9]+ ]]; then
  65     : go on below
  66 elif [[ "$a" == [0-9a-zA-Z-.][0-9a-zA-Z-.]*:[0-9][0-9]* ]]; then
  67     : go on below
  68 else
  69     badrequest; exit 1
  70 fi
  71
  72 if [[ "$h" == HTTP/1.[01][[:space:]]* ]]; then
  73     : go on below
  74 else
  75     badrequest; exit 1
  76 fi
  77
  78 # read more headers until empty line
  79 while [ "$l" != "$CR" ]; do
  80     read l
  81 done
  82
  83 # send status
  84 $ECHO "HTTP/1.0${SPACES}200 OK$CR"
  85 # send empty line
  86 $ECHO "$CR"
  87
  88 # perform proxy (relay) function
  89 $SOCAT $SOCAT_OPTS - tcp:$a || {
  90     $ECHO "HTTP/1.0${SPACES}500 Failed to connect to $a$CR"
  91     $ECHO $CR
  92 }
  93