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NAME

ip_opn_dissect - an internet protocol options dissect function

SYNOPSIS

opn=ip_opn_dissect(pkt,offset,opn_end)

IPOPT_END = 0
IPOPT_NOOP = 1
IPOPT_SEC = 130
IPOPT_LSRR = 131
IPOPT_TIMESTAMP = 68
                 IPOPT_TS_TSONLY = 0
                 IPOPT_TS_TSANDADDR = 1
                 IPOPT_TS_PRESPEC = 3
IPOPT_EXT_SEC = 133
IPOPT_RR = 7
IPOPT_SID = 136
IPOPT_SSRR = 137
IPOPT_MTU = 11
IPOPT_MTU_REPLY = 12
IPOPT_TRACEROUTE = 82
IPOPT_ADDR_EXT = 147
IPOPT_RA = 148
IPOPT_SDBM = 149

DESCRIPTION

dissect IP ' s options.  dissectable are:

End of Option List    +--------+    |00000000|    +--------+	No Operation    +--------+    |00000001|    +--------+	Security    +--------+--------+---//---+---//---+---//---+---//---+    |10000010|00001011|SSS  SSS|CCC  CCC|HHH  HHH|  TCC   |    +--------+--------+---//---+---//---+---//---+---//---+
Loose Source and Record Route    +--------+--------+--------+---------//--------+    |10000011| length | pointer|     route data    |    +--------+--------+--------+---------//--------+	Record Route    +--------+--------+--------+---------//--------+    |00000111| length | pointer|     route data    |    +--------+--------+--------+---------//--------+	Stream Identifier    +--------+--------+--------+--------+    |10001000|00000100|    Stream ID    |    +--------+--------+--------+--------+
Internet Timestamp    +--------+--------+--------+--------+    |01000100| length | pointer|oflw|flg|    +--------+--------+--------+--------+    |         internet address          |    +--------+--------+--------+--------+    |             timestamp             |    +--------+--------+--------+--------+    |                 .                 |                      .	SDBM    +--------+--------+--------+--------+    |10010101| Length |    IP Addr 1    |    +--------+--------+--------+--------+    | IP Addr 1(cont) |    ..........   |    +--------+--------+--------+--------+    |    ..........   |   IP Address N  |    +--------+--------+--------+--------+    | IP Addr N(cont) |      Unused     |    +--------+--------+--------+--------+	Address Extension    +--------+--------+--------+--------+    |10010011|00001010| src IPv7 addr(1)|    +--------+--------+--------+--------+    | src IPv7 addr(2)| dst IPv7 addr(1)|    +--------+--------+--------+--------+    | dst IPv7 addr(2)|    +--------+--------+
Strict Source and Record Route    +--------+--------+--------+---------//--------+    |10001001| length | pointer|     route data    |    +--------+--------+--------+---------//--------+	Probe MTU Option    +--------+--------+--------+--------+    |00001011|00000100|   2 octet value |    +--------+--------+--------+--------+	Reply MTU Option    +--------+--------+--------+--------+    |00001100|00000100|   2 octet value |    +--------+--------+--------+--------+
Traceroute    +-+-+-+-+-+-+-+-+---------------+---------------+---------------+    |0|1 0|1 0 0 1 0|0 0 0 0 1 1 0 0|          ID Number            |    +-+-+-+-+-+-+-+-+---------------+---------------+---------------+    |      Outbound Hop Count       |       Return Hop Count        |    +---------------+---------------+---------------+---------------+    |                     Originator IP Address                     |    +---------------+---------------+---------------+---------------+	Router Alert    +--------+--------+--------+--------+    |10010100|00000100|  2 octet value  |    +--------+--------+--------+--------+	Extended Security    +--------+--------+--------+-------//-------+    |10000101| length |  code  |  add sec info  |    +--------+--------+--------+-------//-------+

references  rfc 791, 1063, 1108, 1393, 1770, 2113

funtion accepts three arguments:
    pkt is a packet reference containing the whole already dissected packet
    offset is the position inside packet to start dissection
    opn_end equals offset plus option length

funtion returns one list:
    opn is a list
    each item of the list is a dissected option
    this is the option's prototype: [option_code,option_length,(option_field1,option_field2,.......,option_fieldN)] 
    note: negative option_code means option exceeds global options length