bgpd: Regularise BGP NLRI sanity checks a bit

* bgp_route.h: (bgp_nlri_sanity_check) The bulk of the args are equivalent
  to a (struct bgp_nlri), consolidate.
* bgp_route.c: (bgp_nlri_sanity_check) Make this a frontend for all afi/safis.
  Including SAFI_MPLS_LABELED_VPN.
  (bgp_nlri_sanity_check_ip) Regular IP NLRI sanity check based on the
  existing code, and adjusted for (struct bgp_nlri *) arg.
* bgp_attr.c: (bgp_mp_reach_parse) Adjust for passing (struct bgp_nlri *)
  to bgp_nlri_sanity_check.
  Get rid of special-casing to not sanity check VPN.
  (bgp_mp_unreach_parse) Ditto.

* bgp_mplsvpn.c: Use the same VPN parsing code for both the sanity
  check and the actual parse.

  (bgp_nlri_parse_vpn) renamed to bgp_nlri_parse_vpn_body and made
  internal.

  (bgp_nlri_parse_vpn_body) Added (bool) argument to control whether it
  is sanity checking or whether it should update routing state for each
  NLRI.  Send a NOTIFY and reset the session, if there's a parsing
  error, as bgp_nlri_sanity_check_ip does, and as is required by the
  RFC.

  (bgp_nlri_parse_vpn) now a wrapper to call _body with update.

  (bgp_nlri_sanity_check_vpn) wrapper to call parser without
  updating.

* bgp_mplsvpn.h: (bgp_nlri_sanity_check_vpn) export for
  bgp_nlri_sanity_check.

* bgp_packet.c: (bgp_update_receive) Adjust for bgp_nlri_sanity_check
  argument changes.

* test/bgp_mp_attr_test.c: Extend to also test the NLRI parsing functions,
  if the initial MP-attr parsing has succeeded.  Fix the NLRI in the
  VPN cases.  Add further VPN tests.

* tests/bgpd.tests/testbgpmpattr.exp: Add the new test cases.

This commit a joint effort of:

Lou Berger <lberger@labn.net>
Donald Sharp <sharpd@cumulusnetworks.com>
Paul Jakma <paul.jakma@hpe.com> / <paul@jakma.org>
8 files changed