[2] RFC 793 - Transmission Control Protocol (2014-12-29 14:15:21 +09:00 版) https://tools.ietf.org/html/rfc793

[1] RFC 6093 - On the Implementation of the TCP Urgent Mechanism (2015-02-15 16:16:20 +09:00 版) https://tools.ietf.org/html/rfc6093

[3] URGパケット ‐ 通信用語の基礎知識 (2015-03-07 15:47:05 +09:00 版) http://www.wdic.org/w/WDIC/URG%E3%83%91%E3%82%B1%E3%83%83%E3%83%88

[4] out of band攻撃 ‐ 通信用語の基礎知識 (2015-03-07 15:47:23 +09:00 版) http://www.wdic.org/w/WDIC/out%20of%20band%E6%94%BB%E6%92%83

[5] Man page of TCP (2015-02-06 06:34:08 +09:00 版) http://linuxjm.sourceforge.jp/html/LDP_man-pages/man7/tcp.7.html

[6] The GNU C Library: Out-of-Band Data (2015-06-15 12:17:45 +09:00 版) http://www.gnu.org/software/libc/manual/html_node/Out_002dof_002dBand-Data.html

[7] RFC 793 - Transmission Control Protocol (2015-07-11 23:50:25 +09:00 版) https://tools.ietf.org/html/rfc793

Urgent Pointer: 16 bits
This field communicates the current value of the urgent pointer as a
positive offset from the sequence number in this segment. The
urgent pointer points to the sequence number of the octet following
the urgent data. This field is only be interpreted in segments with
the URG control bit set.