gsmtap.h: Add some more comments
diff --git a/include/osmocore/gsmtap.h b/include/osmocore/gsmtap.h
index 3f384a4..c5dba79 100644
--- a/include/osmocore/gsmtap.h
+++ b/include/osmocore/gsmtap.h
@@ -21,6 +21,7 @@
#define GSMTAP_TYPE_UM_BURST 0x03 /* raw burst bits */
#define GSMTAP_TYPE_SIM 0x04
+/* sub-types for TYPE_UM_BURST */
#define GSMTAP_BURST_UNKNOWN 0x00
#define GSMTAP_BURST_FCCH 0x01
#define GSMTAP_BURST_PARTIAL_SCH 0x02
@@ -32,6 +33,7 @@
#define GSMTAP_BURST_ACCESS 0x08
#define GSMTAP_BURST_NONE 0x09
+/* sub-types for TYPE_UM */
#define GSMTAP_CHANNEL_UNKNOWN 0x00
#define GSMTAP_CHANNEL_BCCH 0x01
#define GSMTAP_CHANNEL_CCCH 0x02
@@ -45,10 +47,12 @@
#define GSMTAP_CHANNEL_TCH_H 0x0a
#define GSMTAP_CHANNEL_ACCH 0x80
+/* flags for the ARFCN */
#define GSMTAP_ARFCN_F_PCS 0x8000
#define GSMTAP_ARFCN_F_UPLINK 0x4000
#define GSMTAP_ARFCN_MASK 0x3fff
+/* IANA-assigned well-known UDP port for GSMTAP messages */
#define GSMTAP_UDP_PORT 4729
struct gsmtap_hdr {