[ripd] Fix verification of received MD5 authenticated packets

[ripd] Fix verification of received MD5 authenticated packets

2006-01-17 Paul Jakma <paul.jakma@sun.com>

	* ripd.c: (rip_auth_md5) remove pdigest, not needed.
	  Use a local buffer for the auth_str, where it can be properly
	  nul padded. Do so, hence fixing MD5 authentication.
	  Key looked up via key ring should be used in preference to
	  the RIPv1 simple password, not other way around.
	  No need to copy around digests, we can reference them
	  directly.
	  The auth_len received can't be trusted, some implementations
	  lie (e.g. older ripd).
	  (rip_auth_md5_ah_write) rename len local variable to doff
	  to be consistent with other functions.
	  (rip_auth_header_write) add the missing return.
	  (rip_auth_md5_set) use the proper constructs to access stream.