Revert "ipv6 support for old kernels (works only for 3.0.80)"

This reverts commit 49a964e0fea57dc0b89010118096b3c7ad714761.
Revert "fix ipv6 input handler bug"

This reverts commit 2a52234c1cbf04ad98115f2503206e7b9c0c777c.
Revert "input netfilter hook"

This reverts commit 46cde1a473afdf8400a0ad1c161c4c399eda710c.
Revert "minor fixes"

This reverts commit 1e330f88fb37e54df80b7f0a2950d0df5ab8c4b7.
Revert "base support of ipv6"

This reverts commit d73d6b975dbdccb7f56bd67a6dadee6e929173dc.