ie: add advertisement protocol definitions

802.11 defines GAS (generic advertisement service) which can be used
to query supported advertisement protocols from an AP before
authentication/association. Hotspot/OSEN only care about the ANQP
protocol, but the way the IE is structured potentially requires
iterating through several tuples before you reach the ANQP protocol
identifier. Because of this we define all protocol identifiers.

src/ie.h

@@ -234,6 +234,15 @@ enum ie_type {
 	IE_TYPE_OWE_DH_PARAM                         = 256 + 32,
 };
 
+enum ie_advertisement_id {
+	IE_ADVERTISEMENT_ANQP			= 0,
+	IE_ADVERTISEMENT_MIH_SERVICE		= 1,
+	IE_ADVERTISEMENT_MIH_DISCOVERY		= 2,
+	IE_ADVERTISEMENT_EAS			= 3,
+	IE_ADVERTISEMENT_RLQP			= 4,
+	IE_ADVERTISEMENT_VENDOR_SPECIFIC	= 221,
+};
+
 enum ie_rsn_cipher_suite {
 	IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER	= 0x0001,
 	IE_RSN_CIPHER_SUITE_WEP40		= 0x0002,