MFC r314651,r318439,r318440:

r314651:

sys/modules: normalize .CURDIR-relative paths to SRCTOP

This simplifies make output/logic

Tested with: `cd sys/modules; make ALL_MODULES=` on amd64

r318439:

Normalize .PATH on SRCTOP

This will help Jenkins dedupe 9 warnings between the static build and
the module build of ipsec(4).

Missed in SRCTOP conversion in r314651.

MFC with: r314651

r318440:

Normalize SYSDIR on SRCTOP instead of .CURDIR

This is being done to simplify pathing for CFLAGS and source files.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

mac_portacl.c no longer references vnode_if.h.

A cute yet small MAC policy that provides a simple ACL mechanism to
permit users and groups to bind ports for TCP or UDP, and is intended
to be combined with the recently committed support for
net.inet.ip.portrange.reservedhigh. The policy is twiddled using
sysctl(8). To use this module, you will need to compile in MAC
support, and probably set reservedhigh to 0, then twiddle
security.mac.portacl.rules to set things as desired. This policy
module only restricts ports explicitly bound using bind(), not
implicitly bound ports where the port number is selected by the
IP stack. It appears to work properly in my local configuration,
but needs more broad testing.

A sample policy might be:

# sysctl security.mac.portacl.rules="uid:425:tcp:80,uid:425:tcp:79"

This permits uid 425 to bind TCP sockets to ports 79 and 80. Currently
no distinction is made for incoming vs. outgoing ports with TCP,
although that would probably be easy to add.

Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories