MFC r299873

Use strlcpy() instead of strncpy() when copying ifname to ensure
that it is NUL terminated. Additional NUL padding is not required
for short names.

Use sizeof(destination) in a few places instead of IFNAMSIZ.

Cast afp->af_ridreq and afp->af_addreq to make the intent of
the code more obvious.

Reported by: Coverity
CID: 1009628, 1009630, 1009631, 1009632, 1009633, 1009635, 1009638
CID: 1009639, 1009640, 1009641, 1009642, 1009643, 1009644, 1009645
CID: 1009646, 1009647, 1010049, 1010050, 1010051, 1010052, 1010053
CID: 1010054, 1011293, 1011294, 1011295, 1011296, 1011297, 1011298
CID: 1011299, 1305821, 1351720, 1351721

MFC r288305:

Replace N #defines with nitems to simplify ifconfig code slightly

MFC r274246:
Overhaul if_gre(4).

Split it into two modules: if_gre(4) for GRE encapsulation and
if_me(4) for minimal encapsulation within IP.

gre(4) changes:
* convert to if_transmit;
* rework locking: protect access to softc with rmlock,
protect from concurrent ioctls with sx lock;
* correct interface accounting for outgoing datagramms (count only payload size);
* implement generic support for using IPv6 as delivery header;
* make implementation conform to the RFC 2784 and partially to RFC 2890;
* add support for GRE checksums - calculate for outgoing datagramms and check
for inconming datagramms;
* add support for sending sequence number in GRE header;
* remove support of cached routes. This fixes problem, when gre(4) doesn't
work at system startup. But this also removes support for having tunnels with
the same addresses for inner and outer header.
* deprecate support for various GREXXX ioctls, that doesn't used in FreeBSD.
Use our standard ioctls for tunnels.

me(4):
* implementation conform to RFC 2004;
* use if_transmit;
* use the same locking model as gre(4);

PR: 164475

MFC r274289 (by bz):
gcc requires variables to be initialised in two places. One of them
is correctly used only under the same conditional though.

For module builds properly check if the kernel supports INET or INET6,
as otherwise various mips kernels without IPv6 support would fail to build.

MFC r274964:
Add ip_gre.h to ObsoleteFiles.inc.

MFC r274246:
Overhaul if_gre(4).

Split it into two modules: if_gre(4) for GRE encapsulation and
if_me(4) for minimal encapsulation within IP.

gre(4) changes:
* convert to if_transmit;
* rework locking: protect access to softc with rmlock,
protect from concurrent ioctls with sx lock;
* correct interface accounting for outgoing datagramms (count only payload size);
* implement generic support for using IPv6 as delivery header;
* make implementation conform to the RFC 2784 and partially to RFC 2890;
* add support for GRE checksums - calculate for outgoing datagramms and check
for inconming datagramms;
* add support for sending sequence number in GRE header;
* remove support of cached routes. This fixes problem, when gre(4) doesn't
work at system startup. But this also removes support for having tunnels with
the same addresses for inner and outer header.
* deprecate support for various GREXXX ioctls, that doesn't used in FreeBSD.
Use our standard ioctls for tunnels.

me(4):
* implementation conform to RFC 2004;
* use if_transmit;
* use the same locking model as gre(4);

PR: 164475

MFC r274289 (by bz):
gcc requires variables to be initialised in two places. One of them
is correctly used only under the same conditional though.

For module builds properly check if the kernel supports INET or INET6,
as otherwise various mips kernels without IPv6 support would fail to build.

MFC r274964:
Add ip_gre.h to ObsoleteFiles.inc.