Replaced old file: 
('#!/bin/sh\n',)
('# @(#) Sample Gigapxy authorization handler.\n',)
('\n',)
('\n',)
('# Write message into debug log (or STDERR).\n',)
('dbg_msg()\n',)
('{\n',)
('    case "${os}" in\n',)
('        \'Linux\') tstamp=`date +"%Y-%m-%d %H:%M:%S.%N %Z"`;;\n',)
('        *) tstamp=`date +"%Y-%m-%d %H:%M:%S %Z"` ;;\n',)
('    esac\n',)
('\n',)
('    if [ -n "${logfile}" ]; then\n',)
('        echo >>${logfile} "${tstamp} pid=$$\\t$@"\n',)
('    else\n',)
('        echo >&2 "${tstamp} pid=$$\\t$@"\n',)
('    fi\n',)
('}\n',)
('\n',)
('\n',)
('# Perform graceful exit.\n',)
('exit_app()\n',)
('{\n',)
('    dbg_msg "$0 exited $1"\n',)
('    exit 1\n',)
('}\n',)
('\n',)
('\n',)
('# Authenticate using MD5 hash on auth=tkn tail of the channel url.\n',)
('auth_ok()\n',)
('{\n',)
('    return 0;\n',)
("    peer_ip=`echo ${1:?} | cut -d':' -f1`\n",)
("    channel=`echo ${2:?} | cut -d'?' -f1`\n",)
("    auth_tkn=`echo ${2:?} | cut -d'?' -f2 | sed 's/auth=//'`\n",)
('\n',)
('    #phrase="Greetings from ${peer_ip}! Give me ${channel}, please."\n',)
('    phrase="ThisIsCool$peer_ip"\n',)
('    # dbg_msg "phrase=[${phrase}], tkn=${auth_tkn}"\n',)
('\n',)
('    case "${os}" in\n',)
("        'Linux')    hash=`echo -n ${phrase} | md5sum | cut -d' ' -f1` ;;\n",)
("        'FreeBSD')  hash=`echo -n ${phrase} | md5` ;;\n",)
('    esac\n',)
('\n',)
('    # dbg_msg "hash=${hash}, tkn=${auth_tkn}"\n',)
('\n',)
('    if [ -z "${whitelist##*$peer_ip*}" ]; then\n',)
('\treturn 0;\n',)
('    fi\n',)
('\n',)
('    case "$channel" in\n',)
('        udp://239.195.*)\n',)
('                return 0; #Accept the user without auth on 239.195.*\n',)
('        ;;\n',)
('        # http://*)\n',)
('        #         return 0;\n',)
('        # ;;\n',)
('    esac\n',)
('\n',)
('    if [ "${hash}" != "${auth_tkn}" ]; then\n',)
('        return 1\n',)
('    fi\n',)
('\n',)
('    return 0\n',)
('}\n',)
('\n',)
('\n',)
('###\n',)
('# Read requests from STDIN, respond via STDOUT.\n',)
('###\n',)
('\n',)
('os=`uname`\n',)
('\n',)
('if [ $# -lt 1 ]; then\n',)
('    echo >&2 "Usage: $0 logfile|-"\n',)
('    exit 1\n',)
('fi\n',)
('\n',)
('\n',)
('logfile=${1:-}\n',)
('case "${logfile}" in\n',)
("    '-')        logfile='/dev/null';;\n",)
("    'stderr')   logfile=;;\n",)
('esac\n',)
('\n',)
('whitelist_file=${2:-/dev/null}\n',)
('\n',)
('parent_pid=$PPID  # parent of this script shell\n',)
('\n',)
('# arrays suck in posix sh, probably good enough with space as delimiter\n',)
('# whitelist=$(grep "^[^#]" $whitelist_file | tr \'\\n\' \' \')\n',)
('whitelist=$(grep "^[^#]" $whitelist_file)\n',)
('\n',)
('\n',)
('dbg_msg "$0 started, parent=${parent_pid}, n_whitelisted=$(echo "$whitelist" | wc -w)"\n',)
("trap 'exit_app KILLED;' HUP INT QUIT PIPE TERM\n",)
('\n',)
('while read qtag peer_ipport cha_src cli_dst; do\n',)
('        dbg_msg "Got ${qtag} request for ${peer_ipport} ${cha_src}"\n',)
("        if echo $qtag | grep -q '^A[0-9]\\{1,9\\}$'; then\n",)
('            if auth_ok ${peer_ipport} ${cha_src}; then\n',)
('                rc=0; status="ALLOWED"\n',)
('            else\n',)
('                rc=111; status="DENIED"\n',)
('            fi\n',)
('\n',)
('            dbg_msg "${status} tag=${qtag} peer=${peer_ipport} cha=${cha_src} cli=${cli_dst}"\n',)
('            echo "${qtag} ${rc}"\n',)
('        else\n',)
('            dbg_msg "Invalid query ID: [$qtag], request ignored."\n',)
('        fi\n',)
('done\n',)
('\n',)
("exit_app 'OK'\n",)
('\n',)
('# vim: syntax=sh\n',)
('\n',)