- Copy stable/10@296371 to releng/10.3 in preparation for 10.3-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.3.
- Update default pkg(8) configuration to use the quarterly branch.

Approved by: re (implicit)

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Allow the address and ports to be separated by a colon or period rather
than a space to permit directly pasting the output of commands such as
netstat and sockstat on the command line.

Reviewed by: net
MFC after: 1 week

Include param.h for CACHE_LINE_SIZE to unbreak the build.

o) Restructure tcpdrop(8) to provide a facility to try to drop all established
connections. Including a flag to instead output a sequence of tcpdrop(8)
invocations that would accomplish the same thing, which is convenient for
scripting.
o) Make tcpdrop complain if the addresses given to it are entirely in different
address families, rather than failing silently.
o) When cross-referencing httpd(8), do not explicitly specify the apache2 port,
since the example in question is generic.

Normalize usage output.

o Add handling of an IPv4-mapped IPv6 address.
o Use SYSCTL_IN() macro instead of direct call of copyin(9).

Submitted by: ume

o Move sysctl_drop() implementation to sys/netinet/tcp_subr.c where
most of tcp sysctls live.
o There are net.inet[6].tcp[6].getcred sysctls already, no needs in
a separate struct tcp_ident_mapping.

Suggested by: ume

o Implement net.inet.tcp.drop sysctl and userland part, tcpdrop(8)
utility:

The tcpdrop command drops the TCP connection specified by the
local address laddr, port lport and the foreign address faddr,
port fport.

Obtained from: OpenBSD
Reviewed by: rwatson (locking), ru (man page), -current
MFC after: 1 month