Harald Welte <laforge@gnumonks.org>

via https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6792

This is a new dissector for the non-standard Ericsson OM2000 protocol, as it is
used for the OML on A-bis of Ericsson RBS 2xxx BTSs.

It also includes a dissector for a shim-layer protocol that Ericsson uses for
IP-based A-bis like the RBS 2409.  As the protocol is not publicly documented,
I have invented the name "EHDLC" (Ericsson HLDC) for it.



git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@41195 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 34 insertions, 12 deletions

diff --git a/epan/dissectors/packet-gsm_abis_oml.c b/epan/dissectors/packet-gsm_abis_oml.c
index 392d07c9ff..6f54e56bba 100644
--- a/epan/dissectors/packet-gsm_abis_oml.c
+++ b/epan/dissectors/packet-gsm_abis_oml.c
@@ -735,6 +735,7 @@ enum {
 	OML_DIALECT_ETSI,
 	OML_DIALECT_SIEMENS,
 	OML_DIALECT_IPA,
+	OML_DIALECT_ERICSSON,
 };
 
 /* which A-bis OML dialect to use (prefrence) */
@@ -742,6 +743,8 @@ static gint global_oml_dialect = OML_DIALECT_ETSI;
 
 static proto_tree *top_tree;
 
+static dissector_handle_t sub_om2000;
+
 /* TS 12.21 Chapter 8.1 / TS 08.59 */
 static const value_string oml_msg_disc_vals[] = {
 	{ ABIS_OM_MDISC_FOM,	"Formatted O&M" },
@@ -1155,6 +1158,7 @@ static const enum_val_t oml_dialect_enumvals[] = {
 	{ "etsi",	"ETSI/3GPP TS 12.21",	OML_DIALECT_ETSI },
 	{ "siemens",	"Siemens",		OML_DIALECT_SIEMENS },
 	{ "ipaccess",	"ip.access",		OML_DIALECT_IPA },
+	{ "om2000",	"Ericsson OM2000",	OML_DIALECT_ERICSSON },
 	{ NULL, NULL, 0 }
 };
 
@@ -1819,6 +1823,7 @@ dissect_abis_oml(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 	top_tree = tree;
 	if (tree) {
 		guint8 msg_disc = tvb_get_guint8(tvb, offset);
+		guint8 len = tvb_get_guint8(tvb, offset+3);
 
 		ti = proto_tree_add_item(tree, proto_abis_oml, tvb, 0, -1, ENC_NA);
 		oml_tree = proto_item_add_subtree(ti, ett_oml);
@@ -1832,18 +1837,33 @@ dissect_abis_oml(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 		proto_tree_add_item(oml_tree, hf_oml_length, tvb, offset++,
 				    1, ENC_LITTLE_ENDIAN);
 
-		switch (msg_disc) {
-		case ABIS_OM_MDISC_FOM:
-			offset = dissect_oml_fom(tvb, pinfo, oml_tree,
-						 offset, ti);
-			break;
-		case ABIS_OM_MDISC_MANUF:
-			offset = dissect_oml_manuf(tvb, pinfo, oml_tree,							       offset, ti);
-			break;
-		case ABIS_OM_MDISC_MMI:
-		case ABIS_OM_MDISC_TRAU:
-		default:
-			break;
+		if (global_oml_dialect == OML_DIALECT_ERICSSON) {
+			/* Ericsson OM2000 only sharese the common header above
+			 * and has completely custom/proprietary message format
+			 * after that header.  Thus, it makes more sense of
+			 * putting all of that into an external dissector and
+			 * call out to that dissector */
+			tvbuff_t *subtvb;
+			subtvb = tvb_new_subset(tvb, offset, len, len);
+
+			if (sub_om2000)
+				call_dissector(sub_om2000, subtvb, pinfo, tree);
+		} else {
+
+			switch (msg_disc) {
+			case ABIS_OM_MDISC_FOM:
+				offset = dissect_oml_fom(tvb, pinfo, oml_tree,
+							 offset, ti);
+				break;
+			case ABIS_OM_MDISC_MANUF:
+				offset = dissect_oml_manuf(tvb, pinfo, oml_tree,
+							   offset, ti);
+				break;
+			case ABIS_OM_MDISC_MMI:
+			case ABIS_OM_MDISC_TRAU:
+			default:
+				break;
+			}
 		}
 	}
 
@@ -2373,4 +2393,6 @@ proto_reg_handoff_abis_oml(void)
 	} else {
 		/* preferences have been changed */
 	}
+
+	sub_om2000 = find_dissector("gsm_abis_om2000");
 }