MFC r235986:

MFC r235986:

   Use M_ZERO with malloc rather than calling bzero() ourselves.

   Change if () panic() checks to KASSERT()s as they are only
   catching invariants in code flow but not dependent on network
   input/output.

   Move initial assigments indirecting pointers after the lock
   has been aquired.

   Passing layer boundries, reset M_PROTOFLAGS.

   Remove a NULL assignment before free.

Approved by:	re

git-svn-id: svn://svn.freebsd.org/base/stable/9@238241 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f