Detect Topera IPv6 scans when IP options are logged

Detect Topera IPv6 scans when IP options are logged

Added detection for Topera IPv6 scans when --log-ip-options is used in
the ip6tables logging rule.  When this option is not used, the previous                                                                                                                        psad-2.2 release detected Topera scans.  An example TCP SYN packet
generated by Topera when --log-ip-options is used looks like this (note                                                                                                                        the series of empty IP options strings "OPT ( )":

    Dec 20 20:10:40 rohan kernel: [  488.495776] DROP IN=eth0 OUT=                                                                                                                                 MAC=00:1b:b9:76:9c:e4:00:13:46:3a:41:36:86:dd
    SRC=2012:1234:1234:0000:0000:0000:0000:0001                                                                                                                                                    DST=2012:1234:1234:0000:0000:0000:0000:0002 LEN=132 TC=0 HOPLIMIT=64
    FLOWLBL=0 OPT ( ) OPT ( ) OPT ( ) OPT ( ) OPT ( ) OPT ( ) OPT ( )                                                                                                                              OPT ( ) OPT ( ) PROTO=TCP SPT=61287 DPT=1 WINDOW=8192 RES=0x00 SYN
    URGP=0