[bgpd] cleanup, compact and consolidate capability parsing code

[bgpd] cleanup, compact and consolidate capability parsing code

2007-07-26 Paul Jakma <paul.jakma@sun.com>

	* (general) Clean up and compact capability parsing slightly.
	  Consolidate validation of length and logging of generic TLV, and
	  memcpy of capability data, thus removing such from cap specifc
	  code (not always present or correct).
	* bgp_open.h: Add structures for the generic capability TLV header
	  and for the data formats of the various specific capabilities we
	  support.  Hence remove the badly named, or else misdefined, struct
	  capability.
	* bgp_open.c: (bgp_capability_vty_out) Use struct capability_mp_data.
	  Do the length checks *before* memcpy()'ing based on that length
	  (stored capability - should have been validated anyway on input,
	  but..).
	  (bgp_afi_safi_valid_indices) new function to validate (afi,safi)
	  which is about to be used as index into arrays, consolidates
	  several instances of same, at least one of which appeared to be
	  incomplete..
	  (bgp_capability_mp) Much condensed.
	  (bgp_capability_orf_entry) New, process one ORF entry
	  (bgp_capability_orf) Condensed. Fixed to process all ORF entries.
	  (bgp_capability_restart) Condensed, and fixed to use a
	  cap-specific type, rather than abusing capability_mp.
	  (struct message capcode_str) added to aid generic logging.
	  (size_t cap_minsizes[]) added to aid generic validation of
	  capability length field.
	  (bgp_capability_parse) Generic logging and validation of TLV
	  consolidated here. Code compacted as much as possible.
	* bgp_packet.c: (bgp_open_receive) Capability parsers now use
	  streams, so no more need here to manually fudge the input stream
	  getp.
	  (bgp_capability_msg_parse) use struct capability_mp_data. Validate
	  lengths /before/ memcpy. Use bgp_afi_safi_valid_indices.
	  (bgp_capability_receive) Exported for use by test harness.
	* bgp_vty.c: (bgp_show_summary) fix conversion warning
	  (bgp_show_peer) ditto
	* bgp_debug.h: Fix storage 'extern' after type 'const'.
        * lib/log.c: (mes_lookup) warning about code not being in
          same-number array slot should be debug, not warning. E.g. BGP
          has several discontigious number spaces, allocating from
          different parts of a space is not uncommon (e.g. IANA
          assigned versus vendor-assigned code points in some number
          space).