--- /dev/null
+#!/usr/bin/perl
+###############################################################################
+# #
+# IPFire.org - A linux based firewall #
+# Copyright (C) 2015 IPFire Development Team #
+# #
+# This program is free software: you can redistribute it and/or modify #
+# it under the terms of the GNU General Public License as published by #
+# the Free Software Foundation, either version 3 of the License, or #
+# (at your option) any later version. #
+# #
+# This program is distributed in the hope that it will be useful, #
+# but WITHOUT ANY WARRANTY; without even the implied warranty of #
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
+# GNU General Public License for more details. #
+# #
+# You should have received a copy of the GNU General Public License #
+# along with this program. If not, see <http://www.gnu.org/licenses/>. #
+# #
+###############################################################################
+
+use strict;
+use threads;
+use threads::shared;
+use Thread::Queue;
+use Linux::Inotify2;
+
+require Guardian::Parser;
+
+# Array to store the monitored logfiles.
+my @monitored_files = (
+ "/var/log/snort/alert",
+);
+
+# Create the main queue. It is used to store and process all events which are
+# reported and enqueued by the worker threads.
+my $queue :shared = new Thread::Queue or die "Could not create new, empty queue. $!\n";;
+
+# Call Init function to initzialize guardian.
+&Init();
+
+# Infinite main loop, which processes all queued events.
+while(1) {
+ # Get the amount of elements in our queue.
+ # "undef" will be returned if it is empty.
+ my $current_events = $queue->pending();
+
+ # If there is at least one element enqued
+ if($current_events > 0) {
+ # Grab the data of the top enqueued event.
+ my $event = $queue->peek();
+
+ print "Got event: $event\n";
+
+ # Drop processed event from queue.
+ $queue->dequeue();
+ }
+
+ # XXX
+ # Temporary workaround to reduce the load of the main process.
+ sleep(1);
+}
+
+#
+## Init function.
+#
+## This function contains code which has to be executed while guardian
+## is starting.
+#
+sub Init () {
+ # Loop through the array of which files should be monitored and
+ # create a worker thread for each single one.
+ foreach my $monitored_file (@monitored_files) {
+ # Check if the file exists and is readable.
+ if (-r "$monitored_file") {
+ # Create worker thread for the file.
+ threads->create(\&Worker,$monitored_file);
+ }
+ }
+}
+
+#
+## Worker function.
+#
+## This function is responsible for monitoring modifications of the given logfile,
+## read them and pass them to the message parser.
+#
+## To get file modifications the inotify subsystem of the linux kernel is used.
+#
+## In order to prevent from permanently read and keep files opened, or dealing
+## with huge logfiles, at initialization time of the worker process, the file will
+## be opened once and the cursor position of the end of file (EOF) get stored. When
+## reading any newly added lines from the file, we directly can jump to the last
+## known position and get these lines. Afterwards, we store the current curser position
+## again, so we can do it in this way over and over again.
+#
+## All read lines get stored in an array, which will be passed to the Parser.
+#
+## If any response (action) from the parser get recieved, it will be put into the
+## shared event queue.
+#
+sub Worker ($) {
+ my $file = @_[0];
+
+ # Get the fileposition.
+ my $fileposition = &Init_fileposition("$file");
+
+ # Create inotify watcher.
+ my $watcher = new Linux::Inotify2 or die "Could not use inotify. $!\n";
+
+ # Monitor the specified file.
+ $watcher->watch("$file", IN_MODIFY) or die "Could not monitor $file. $!\n";
+
+ # Get all notifications.
+ while ($watcher->read) {
+ my @message = ();
+
+ # Open the file.
+ open (FILE, $file) or die "Could not open $file. $!\n";
+
+ # Seek to the last known position.
+ seek (FILE, $fileposition, 0);
+
+ # Get the log message.
+ while (my $line = <FILE>) {
+ # Remove any newlines.
+ chomp $line;
+
+ # Add all lines to the message array.
+ push (@message, $line);
+ }
+
+ # Update fileposition.
+ $fileposition = tell(FILE);
+
+ # Close file.
+ close(FILE);
+
+ # Send filename and message to the parser,
+ # which will return if an action has to be performed.
+ my @action = &Guardian::Parser::Parser("$file", @message);
+
+ # Send the action to the main process and put it into
+ # the queue.
+ if (@action) {
+ # Lock the queue.
+ lock($queue);
+
+ # Put the required action into the queue.
+ $queue->enqueue(@action);
+ }
+ }
+}
+
+#
+## Function for fileposition initialization.
+#
+## This function is used to get the cursor position of the end of file (EOF) of
+## a specified file.
+#
+## In order to prevent from permanently read and keep files opened, or dealing
+## with huge logfiles, at initialization time of the worker processes, the file will
+## be opened once and the cursor position of the end of file (EOF) get stored.
+#
+sub Init_fileposition ($) {
+ my $file = $_[0];
+
+ # Open the file.
+ open(FILE, $file) or die "Could not open $file. $!\n";
+
+ # Just seek to the end of the file (EOF).
+ seek(FILE, 0, 2);
+
+ # Get and store the position.
+ my $position = tell(FILE),
+
+ # Close the file again.
+ close(FILE);
+
+ # Return the position.
+ return $position;
+}
--- /dev/null
+package Guardian::Parser;
+use strict;
+use warnings;
+
+use Exporter qw(import);
+
+our @EXPORT_OK = qw(Parser);
+
+# This hash contains all supported logfiles and which function
+# has to be called to parse them in the right way.
+my %logfile_parsers = (
+ "/var/log/snort/alert" => \&message_parser_snort,
+);
+
+#
+## The main parsing function.
+#
+## It is used to determine which sub-parser has to be used to
+## parse the given message in the right way and to return if
+## any action should be performed.
+#
+sub Parser ($$) {
+ my ($file, @message) = @_;
+
+ # If no responsible message parser could be found, just return nothing.
+ unless (exists($logfile_parsers{$file})) {
+ return;
+ }
+
+ # Call responsible logfile parser.
+ my $action = $logfile_parsers{$file}->(@message);
+
+ # Return which action should be performed.
+ return $action;
+}
+
+#
+## The Snort message parser.
+#
+## This subfunction is responsible for parsing sort alerts and determine if
+## an action should be performed.
+#
+sub message_parser_snort($) {
+ my @message = @_;
+
+ # XXX
+ # Currently this parser just returns a simple message.
+ return "snort_parser_return\n";
+}
+
+1;
projects / people / stevee / guardian.git / commitdiff
