Improv arguments parsing

diff --git a/example/diameter/pcapDecoder/tsharkDecoder.sh b/example/diameter/pcapDecoder/tsharkDecoder.sh
index b6c98aa..90c3384 100755 (executable)
--- a/example/diameter/pcapDecoder/tsharkDecoder.sh
+++ b/example/diameter/pcapDecoder/tsharkDecoder.sh
@@ -42,35 +42,71 @@
 # VARIABLES #
 #############
 tmpdir=$(mktemp -d)
-[ -z "$TSHARK_DECODER_NON_STANDARD_PORTS" ] && TSHARK_DECODER_NON_STANDARD_PORTS="13868"
 
 #############
 # FUNCTIONS #
 #############
 
-usage () {
-  echo "Usage: $0 <pcap_file> [results_dir]"
+usage() {
   echo
-  echo "       pcap_file:   pcap formatted file to be processed."
-  echo "       results_dir: directory where results are stored."
-  echo "                    By default, pcap file dirname is used."
+  echo "Usage: $0 [-h|--help] [-o|--other-ports] [-d|--results-dir] <pcap>"
+  echo
+  echo "       -h|--help:        this usage help."
+  echo "       -o|--other-ports: space-separated list of ports which frames"
+  echo "                         will be decoded as diameter protocol although"
+  echo "                         not being standard. For example, we could use"
+  echo "                         \"13868\" to disect the Ericsson Sy variant."
+  echo "       -d|--results-dir: directory where results are stored."
+  echo "                         By default, pcap dirname."
+  echo
+  echo "       pcap:             pcap formatted file to be processed."
   echo
   echo "       The utility, dumps the extracted hexadecimal content"
   echo "       and useful information as timestamps, source and"
   echo "       destination:"
-  echo "          <results_dir>/<frame sequence>.hex"
-  echo "          <results_dir>/<frame sequence>.metadata"
-  echo
-  echo
-  echo "       TSHARK_DECODER_NON_STANDARD_PORTS: environment variable"
-  echo "       defined as a space-separated list of ports which frames"
-  echo "       will be decoded as diameter protocol. By default, \"13868\""
-  echo "       is used when the variable has not been exported in shell,"
-  echo "       in order to disect the Ericsson Sy variant."
+  echo "          <results directory>/<frame sequence>.hex"
+  echo "          <results directory>/<frame sequence>.metadata"
   echo
   _exit
 }
 
+parse_arguments() {
+  OTHER_PORTS=
+  RESULTS_DIR=
+  PCAP_FILE=
+
+  while [ $# -gt 0 ]; do
+    case $1 in
+      -h|--help)
+        usage
+      ;;
+
+      -o|--other-ports)
+        OTHER_PORTS="$2"
+        [ -z "$OTHER_PORTS" ] && _exit "Missing non-standard ports list"
+        shift
+      ;;
+
+      -d|--results-dir)
+        RESULTS_DIR=$2
+        shift
+      ;;
+
+      *)
+        first=$(echo $1 | cut -c1)
+        [ "$first" = "-" ] && _exit "Unsupported script option: $1. Type '$SCR_BN -h' (or --help) to print the available options."
+        PCAP_FILE=$1
+      ;;
+    esac
+    shift
+  done
+
+  [ -z "$PCAP_FILE" ] && _exit "Missing pcap file"
+  [ ! -f "$PCAP_FILE" ] && _exit "Cannot found provided pcap file '$PCAP_FILE' !!"
+  [ -z "$RESULTS_DIR" ] && RESULTS_DIR=`dirname $PCAP_FILE`
+  [ ! -d $RESULTS_DIR ] && _exit "The results directory '$RESULTS_DIR' must exists !!"
+}
+
 _exit () {
   echo
   echo -e $1
@@ -95,29 +131,22 @@ echo "Diameter buffer extractor from PCAP raw file"
 echo "============================================"
 echo
 
-# Usage:
-[ "$1" = "" ] && usage
-
-# Pcap file:
-PCAP_FILE=$1
-[ ! -f $PCAP_FILE ] && _exit "Cannot found provided pcap file '$1' !!"
+# Arguments:
+[ "$1" = "" -o "$1" = "--help" -o "$1" = "-h" ] && usage
+parse_arguments "$@"
 
 # Tshark available:
 which tshark >/dev/null
 [ $? -ne 0 ] && _exit "Missing 'tshark' tool !!"
 
-# Optional result dir:
-RESULTS_DIR=`dirname $PCAP_FILE`
-[ "$2" != "" ] && RESULTS_DIR=$2
-[ ! -d $RESULTS_DIR ] && _exit "The results directory '$RESULTS_DIR' must exists !!"
-
 # Get the frames with diameter content (take care about '-2' two-pass option and don't add it, because we need to get reassembled parts in their corresponding frames):
 # Fields needed (we won't need diameter.hopbyhopid & diameter.endtoendid to verify diameter message as hint patterns; length management will be enough):
 FIELDS_DIAMETER="-e diameter.cmd.code -e diameter.flags.request -e diameter.applicationId -e diameter.hopbyhopid -e diameter.endtoendid -e diameter.length"
 FIELDS="-e frame.number -e frame.time_epoch -e ip.src_host -e ip.dst_host $FIELDS_DIAMETER -e tcp.len -e frame.protocols -e tcp.segment"
 # Disect selectors for non-standard diameter ports:
-for port in $TSHARK_DECODER_NON_STANDARD_PORTS
+for port in $OTHER_PORTS
 do
+  echo "Taking tcp port $port to be decoded as diameter protocol"
   DISECT_SELECTORS="$DISECT_SELECTORS -d tcp.port=$port,diameter"
 done