fix various typos in comments.

Separate nexthop caches from the routing table

By this change, nexthop caches (IP-MAC address pair) are not stored
in the routing table anymore. Instead nexthop caches are stored in
each network interface; we already have lltable/llentry data structure
for this purpose. This change also obsoletes the concept of cloning/cloned
routes. Cloned routes no longer exist while cloning routes still exist
with renamed to connected routes.

Noticeable changes are:
- Nexthop caches aren't listed in route show/netstat -r
- sysctl(NET_RT_DUMP) doesn't return them
- If RTF_LLDATA is specified, it returns nexthop caches
- Several definitions of routing flags and messages are removed
- RTF_CLONING, RTF_XRESOLVE, RTF_LLINFO, RTF_CLONED and RTM_RESOLVE
- RTF_CONNECTED is added
- It has the same value of RTF_CLONING for backward compatibility
- route's -xresolve, -[no]cloned and -llinfo options are removed
- -[no]cloning remains because it seems there are users
- -[no]connected is introduced and recommended
to be used instead of -[no]cloning
- route show/netstat -r drops some flags
- 'L' and 'c' are not seen anymore
- 'C' now indicates a connected route
- Gateway value of a route of an interface address is now not
a L2 address but "link#N" like a connected (cloning) route
- Proxy ARP: "arp -s ... pub" doesn't create a route

You can know details of behavior changes by seeing diffs under tests/.

Proposed on tech-net and tech-kern:
http://mail-index.netbsd.org/tech-net/2016/03/11/msg005701.html

zeroize the rest of the comparable struct before adding it to the rb tree

Store local bindings in a rbtree

check route messages sizes more carefully
cache pid
treat every message at a time, even if there are more messages to read
interpret also cloning routes

The latter two should fix the ldp_regen test

* use a flag in label struct in order to determine if we should treat the
associated routes using RTF_HOST
* clean the mess in flush_mpls_routes that could result in accessing
uninitialized memory

don't connect on first hello, there are chances that ours is not seen yet
setproctitle with ldp id - useful for rump kernels testing
fix a memory leak in ldp_peer_new
don't holddown if already holded down
peer sockets are now non-blocking
connected routes deletes are now processed
check if peer is connected before attempting to sending label mappings

* rework the reattachment code
* build an implnull label when a route is added and let mpls_add_label
to take care of relabelling
* take out last piece of the code where we do route lookups - we should have
every information we need in labels
* tested these changes using a number of rump kernels and some couple of
thousands of flapping routes

Make sure labels are always updated when a route is added and when a peer
is added
Rework mpls_add_label according to that so no route refresh is done anymore
Use poll when reading the PF_ROUTE socket
setsockopt SO_USELOOPBACK on the PF_ROUTE socket
Output some information on SIGINFO
Allow map changing for a ldp peer
Finally fix the connected routes admission into labels
Correct the route trigger when a label map is received

branches: 1.16.2;
create binding for connected routes on startup
decay an warning message to debug only

retire union_ntoa, replace it with satos
check for valid sizes on PF_ROUTE socket
minor comment update

correct loopback address test
correct addr add/del handling

add code for address and address withdraw messages
get rid of unused fields in tlv struct

sprinkle more const

speed up a little bit the string<->prefixlen transforms

modify structures in order to accomodate IPv6 according to
draft-ietf-mpls-ldp-ipv6. Correct a little bit IPv6 hello path

branches: 1.9.2;
Add __printflike attribution to use vprintf and friends with an argument
as format string.

branches: 1.8.2;
Correct prefixlen->sockaddr calculation. Now ldpd may finally allow MPLS
forwarding for default route.

shorten some execution paths related to check_route() and get_route()
statify a bit
don't assume AF_INET in a debug message

* add no-default-route option into configuration file and check it before
rejecting default-route
* exit process in case of error into the main loop
* complete FSM for RTM_CHANGE
* Check if we overflow pollfd array

branches: 1.5.2;
get rid of unused variable/assignments

use RT_ROUNDUP provided by net/route.h

branches: 1.3.2;
check from_cidr_to_union() result

- no cast for malloc
- malloc + memset = calloc
- sizeof(type) -> sizeof(*var)
- small indents

Add ldpd, a RFC 3036 compatible LDP speaker.

Separate nexthop caches from the routing table

By this change, nexthop caches (IP-MAC address pair) are not stored
in the routing table anymore. Instead nexthop caches are stored in
each network interface; we already have lltable/llentry data structure
for this purpose. This change also obsoletes the concept of cloning/cloned
routes. Cloned routes no longer exist while cloning routes still exist
with renamed to connected routes.

Noticeable changes are:
- Nexthop caches aren't listed in route show/netstat -r
- sysctl(NET_RT_DUMP) doesn't return them
- If RTF_LLDATA is specified, it returns nexthop caches
- Several definitions of routing flags and messages are removed
- RTF_CLONING, RTF_XRESOLVE, RTF_LLINFO, RTF_CLONED and RTM_RESOLVE
- RTF_CONNECTED is added
- It has the same value of RTF_CLONING for backward compatibility
- route's -xresolve, -[no]cloned and -llinfo options are removed
- -[no]cloning remains because it seems there are users
- -[no]connected is introduced and recommended
to be used instead of -[no]cloning
- route show/netstat -r drops some flags
- 'L' and 'c' are not seen anymore
- 'C' now indicates a connected route
- Gateway value of a route of an interface address is now not
a L2 address but "link#N" like a connected (cloning) route
- Proxy ARP: "arp -s ... pub" doesn't create a route

You can know details of behavior changes by seeing diffs under tests/.

Proposed on tech-net and tech-kern:
http://mail-index.netbsd.org/tech-net/2016/03/11/msg005701.html

zeroize the rest of the comparable struct before adding it to the rb tree

Store local bindings in a rbtree

check route messages sizes more carefully
cache pid
treat every message at a time, even if there are more messages to read
interpret also cloning routes

The latter two should fix the ldp_regen test

* use a flag in label struct in order to determine if we should treat the
associated routes using RTF_HOST
* clean the mess in flush_mpls_routes that could result in accessing
uninitialized memory

don't connect on first hello, there are chances that ours is not seen yet
setproctitle with ldp id - useful for rump kernels testing
fix a memory leak in ldp_peer_new
don't holddown if already holded down
peer sockets are now non-blocking
connected routes deletes are now processed
check if peer is connected before attempting to sending label mappings

* rework the reattachment code
* build an implnull label when a route is added and let mpls_add_label
to take care of relabelling
* take out last piece of the code where we do route lookups - we should have
every information we need in labels
* tested these changes using a number of rump kernels and some couple of
thousands of flapping routes

Make sure labels are always updated when a route is added and when a peer
is added
Rework mpls_add_label according to that so no route refresh is done anymore
Use poll when reading the PF_ROUTE socket
setsockopt SO_USELOOPBACK on the PF_ROUTE socket
Output some information on SIGINFO
Allow map changing for a ldp peer
Finally fix the connected routes admission into labels
Correct the route trigger when a label map is received

branches: 1.16.2;
create binding for connected routes on startup
decay an warning message to debug only

retire union_ntoa, replace it with satos
check for valid sizes on PF_ROUTE socket
minor comment update

correct loopback address test
correct addr add/del handling

add code for address and address withdraw messages
get rid of unused fields in tlv struct

sprinkle more const

speed up a little bit the string<->prefixlen transforms

modify structures in order to accomodate IPv6 according to
draft-ietf-mpls-ldp-ipv6. Correct a little bit IPv6 hello path

branches: 1.9.2;
Add __printflike attribution to use vprintf and friends with an argument
as format string.

branches: 1.8.2;
Correct prefixlen->sockaddr calculation. Now ldpd may finally allow MPLS
forwarding for default route.

shorten some execution paths related to check_route() and get_route()
statify a bit
don't assume AF_INET in a debug message

* add no-default-route option into configuration file and check it before
rejecting default-route
* exit process in case of error into the main loop
* complete FSM for RTM_CHANGE
* Check if we overflow pollfd array

branches: 1.5.2;
get rid of unused variable/assignments

use RT_ROUNDUP provided by net/route.h

branches: 1.3.2;
check from_cidr_to_union() result

- no cast for malloc
- malloc + memset = calloc
- sizeof(type) -> sizeof(*var)
- small indents

Add ldpd, a RFC 3036 compatible LDP speaker.