bgpd: don't make any assumptions about the size of an enum

The size of an enum is compiler dependent and thus we shouldn't use
enums inside structures that represent fields of a packet.

Problem detected by the 'test_capability' unit test.

The problem was not apparent before because the 'iana_safi_t' enum didn't
exist and 'safi_t' was a typedef to uint8_t. Now we have two different
enums, 'iana_afi_t' and 'iana_safi_t', and both need to be encoded in
different ways on the wire (2 bytes vs 1 byte).

Signed-off-by: Renato Westphal <[email protected]>

Author: rwestphal

bgpd/bgp_open.h

@@ -29,9 +29,9 @@ struct capability_header {
 
 /* Generic MP capability data */
 struct capability_mp_data {
-	iana_afi_t afi;
+	uint16_t afi; /* iana_afi_t */
 	u_char reserved;
-	iana_safi_t safi;
+	uint8_t safi; /* iana_safi_t */
 };
 
 struct capability_as4 {

bgpd/bgpd.h

@@ -922,10 +922,10 @@ DECLARE_QOBJ_TYPE(peer)
    stream. */
 struct bgp_nlri {
 	/* AFI.  */
-	afi_t afi;
+	uint16_t afi; /* iana_afi_t */
 
 	/* SAFI.  */
-	safi_t safi;
+	uint8_t safi; /* iana_safi_t */
 
 	/* Pointer to NLRI byte stream.  */
 	u_char *nlri;