[bgpd] Add support for AS_PATHLIMIT / draft-ietf-idr-as-pathlimit

[bgpd] Add support for AS_PATHLIMIT / draft-ietf-idr-as-pathlimit

2007-07-31 Paul Jakma <paul.jakma@sun.com>

	* (general) Support for draft-ietf-idr-as-pathlimit-03.
	* bgp_attr.h: (struct attr) Add pathlimit struct
          bgp_attr.c: (attr_str) Add BGP_ATTR_AS_PATHLIMIT string.
          (attrhash_key_make) tally pathlimit too
          (attrhash_cmp) cmp pathlimit attr
          (bgp_attr_aspathlimit) New, parse AS_PATHLIMIT attr.
          (bgp_attr_parse) ditto
          (bgp_packet_attribute) Write out AS_PATHLIMIT when set
          (bgp_dump_routes_attr) ditto
         * bgp_route.h: (struct bgp_static) Add TTL field
         * bgp_route.c: (bgp_announce_check) Drop paths that are over
           their hop-count TTL before sending via EBGP.
           Mangle ASN in pathlimit for confeds/private as best we can.
           (bgp_static_update_{rsclient,main}) Add any configure pathlimit
           information.
           (bgp_pathlimit_update_parents) New, update atomic-aggr setting for
           parents of an aspathlimit'ed static.
           (bgp_static_set) Add TTL argument, for all the 'bgp network'
           commands.
           Call previous for TTL changed statics.
           (bgp_static_unset) Call pathlimit_update_parents.
           (various bgp network commands) Add 'pathlimit <0-255>' qualifier
           to all the various forms, bar route-map - which can set ttl
           itself.
         * bgp_routemap.c: (general) Add support for 'set pathlimit ttl' and
           'match pathlimit as'.
         * doc/bgpd.texi: Document 'network ... pathlimit <ttl>'