Add feature to force the selection of source IP address

Based/previous work on an idea from deraadt@
Input from claudio@, djm@, deraadt@, sthen@

OK deraadt@

The algorithm creating the routing addresses in route(8) and arp(6)
were still not correct. While the values written to the kernel are
fine, the bytes for padding were taken from memory after the sockaddr
structs.
In route(8) the union of sockaddrs can be made larger, so that the
padding is taken from there.
In arp(8) the size of the struct is known. Copy only the struct
and advance over the padding. The memory has been zeroed before.
Merge all address size fixes from arp(8) into ndp(8).
OK claudio@

Sync p_rttables() to netstat(1) version. Pointed out by claudio and
mpi.

Remaining differences are pledge and priority handling which only
route(8) has.

While here switch flushroutes to get_sysctl() function.
OK benno

tableid is either initialized to the current routing table or to the
one specified by the T flag. No need to pass a flag around if the
tableid is valid. It always is.

This code is now in sync between flushroutes() and p_rttables().

OK benno, no objection claudio

Print the correct netmask instead of /0 when flushing routes to networks.

Issue reported by jsing@, ok stsp@

On systems with a full routing table (550k+), we often want to be able to
look at the routes with a priority, or to display all routes that do not
have a specific priority (normally, don't show bgp).

We are intentionally not updating netstat -r yet, as we do not have a
good flag to use.

first version from, and OK benno@

Sync show.c to what we have in netstat.c (at least steal some good idioms
from there). OK sthen@ mpi@ jca@

Make route(8) use the ROUTE_TABLEFILTER and change the code so that
route(8) will default to the process rtableid.
route -T 1 exec route add default 192.168.1.1
route -T 1 exec route -n show
These commands will now operate outmatically on rtable 1 and not on
rtable 0 as it was done before.
OK henning@

Add '-label' to specify that you only want to see routes having the
given label. No change to existing functionality.

ok henning@ claudio@

Print MPLS information in route -n get and do some cleanup in the show code.
OK michele@

make route show work on secondary tables, using the just committed
extension to the syctl NET_RT_DUMP interface, claudio ok

Kill unused Aflag support that sneeked in via netstat code.

more bitrot bites the dust

ansi, knf, and other style nits; ok henning

remove -S, -src, -srcmask, and other source routing stuff. ok henning

Make route show output similar to netstat -r output.
OK cedric@ millert@

The algorithm creating the routing addresses in route(8) and arp(6)
were still not correct. While the values written to the kernel are
fine, the bytes for padding were taken from memory after the sockaddr
structs.
In route(8) the union of sockaddrs can be made larger, so that the
padding is taken from there.
In arp(8) the size of the struct is known. Copy only the struct
and advance over the padding. The memory has been zeroed before.
Merge all address size fixes from arp(8) into ndp(8).
OK claudio@

Sync p_rttables() to netstat(1) version. Pointed out by claudio and
mpi.

Remaining differences are pledge and priority handling which only
route(8) has.

While here switch flushroutes to get_sysctl() function.
OK benno

tableid is either initialized to the current routing table or to the
one specified by the T flag. No need to pass a flag around if the
tableid is valid. It always is.

This code is now in sync between flushroutes() and p_rttables().

OK benno, no objection claudio

Print the correct netmask instead of /0 when flushing routes to networks.

Issue reported by jsing@, ok stsp@

On systems with a full routing table (550k+), we often want to be able to
look at the routes with a priority, or to display all routes that do not
have a specific priority (normally, don't show bgp).

We are intentionally not updating netstat -r yet, as we do not have a
good flag to use.

first version from, and OK benno@

Sync show.c to what we have in netstat.c (at least steal some good idioms
from there). OK sthen@ mpi@ jca@

Make route(8) use the ROUTE_TABLEFILTER and change the code so that
route(8) will default to the process rtableid.
route -T 1 exec route add default 192.168.1.1
route -T 1 exec route -n show
These commands will now operate outmatically on rtable 1 and not on
rtable 0 as it was done before.
OK henning@

Add '-label' to specify that you only want to see routes having the
given label. No change to existing functionality.

ok henning@ claudio@

Print MPLS information in route -n get and do some cleanup in the show code.
OK michele@

make route show work on secondary tables, using the just committed
extension to the syctl NET_RT_DUMP interface, claudio ok

Kill unused Aflag support that sneeked in via netstat code.

more bitrot bites the dust

ansi, knf, and other style nits; ok henning

remove -S, -src, -srcmask, and other source routing stuff. ok henning

Make route show output similar to netstat -r output.
OK cedric@ millert@

Sync p_rttables() to netstat(1) version. Pointed out by claudio and
mpi.

Remaining differences are pledge and priority handling which only
route(8) has.

While here switch flushroutes to get_sysctl() function.
OK benno

tableid is either initialized to the current routing table or to the
one specified by the T flag. No need to pass a flag around if the
tableid is valid. It always is.

This code is now in sync between flushroutes() and p_rttables().

OK benno, no objection claudio

Print the correct netmask instead of /0 when flushing routes to networks.

Issue reported by jsing@, ok stsp@

On systems with a full routing table (550k+), we often want to be able to
look at the routes with a priority, or to display all routes that do not
have a specific priority (normally, don't show bgp).

We are intentionally not updating netstat -r yet, as we do not have a
good flag to use.

first version from, and OK benno@

Sync show.c to what we have in netstat.c (at least steal some good idioms
from there). OK sthen@ mpi@ jca@

Make route(8) use the ROUTE_TABLEFILTER and change the code so that
route(8) will default to the process rtableid.
route -T 1 exec route add default 192.168.1.1
route -T 1 exec route -n show
These commands will now operate outmatically on rtable 1 and not on
rtable 0 as it was done before.
OK henning@

Add '-label' to specify that you only want to see routes having the
given label. No change to existing functionality.

ok henning@ claudio@

Print MPLS information in route -n get and do some cleanup in the show code.
OK michele@

make route show work on secondary tables, using the just committed
extension to the syctl NET_RT_DUMP interface, claudio ok

Kill unused Aflag support that sneeked in via netstat code.

more bitrot bites the dust

ansi, knf, and other style nits; ok henning

remove -S, -src, -srcmask, and other source routing stuff. ok henning

Make route show output similar to netstat -r output.
OK cedric@ millert@

Print the correct netmask instead of /0 when flushing routes to networks.

Issue reported by jsing@, ok stsp@

On systems with a full routing table (550k+), we often want to be able to
look at the routes with a priority, or to display all routes that do not
have a specific priority (normally, don't show bgp).

We are intentionally not updating netstat -r yet, as we do not have a
good flag to use.

first version from, and OK benno@

Sync show.c to what we have in netstat.c (at least steal some good idioms
from there). OK sthen@ mpi@ jca@

Make route(8) use the ROUTE_TABLEFILTER and change the code so that
route(8) will default to the process rtableid.
route -T 1 exec route add default 192.168.1.1
route -T 1 exec route -n show
These commands will now operate outmatically on rtable 1 and not on
rtable 0 as it was done before.
OK henning@

Add '-label' to specify that you only want to see routes having the
given label. No change to existing functionality.

ok henning@ claudio@

Print MPLS information in route -n get and do some cleanup in the show code.
OK michele@

make route show work on secondary tables, using the just committed
extension to the syctl NET_RT_DUMP interface, claudio ok

Kill unused Aflag support that sneeked in via netstat code.

more bitrot bites the dust

ansi, knf, and other style nits; ok henning

remove -S, -src, -srcmask, and other source routing stuff. ok henning

Make route show output similar to netstat -r output.
OK cedric@ millert@