Reenable ieee 802.3 encapsulation and small cleanups/updates

Change-Id: I6674140b79bb21121edbd3caa371b7d0f179811a
Reviewed-on: https://code.wireshark.org/review/25982
Reviewed-by: Anders Broman <a.broman58@gmail.com>
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Tested-by: Petri Dish Buildbot
Reviewed-by: Jörg Mayer <jmayer@loplof.de>

1 files changed, 35 insertions, 25 deletions

diff --git a/epan/dissectors/packet-vntag.c b/epan/dissectors/packet-vntag.c
index 9aee26194b..2e39136848 100644
--- a/epan/dissectors/packet-vntag.c
+++ b/epan/dissectors/packet-vntag.c
@@ -11,6 +11,9 @@
 
 #include <epan/packet.h>
 #include <epan/etypes.h>
+#include <epan/expert.h>
+#include <epan/tfs.h>
+#include <epan/dissectors/packet-ieee8023.h>
 
 void proto_register_vntag(void);
 void proto_reg_handoff_vntag(void);
@@ -22,17 +25,27 @@ static int proto_vntag = -1;
 static int hf_vntag_etype = -1;
 static int hf_vntag_dir = -1;
 static int hf_vntag_ptr = -1;
-static int hf_vntag_vif_list_id = -1;
 static int hf_vntag_dst = -1;
 static int hf_vntag_looped = -1;
 static int hf_vntag_r = -1;
 static int hf_vntag_version = -1;
 static int hf_vntag_src = -1;
-/* static int hf_vntag_len = -1; */
+static int hf_vntag_len = -1;
 static int hf_vntag_trailer = -1;
 
 static gint ett_vntag = -1;
 
+static expert_field ei_vntag_len = EI_INIT;
+
+static const true_false_string vntag_dir_tfs = {
+        "From Bridge",
+        "To Bridge"
+};
+static const true_false_string vntag_ptr_tfs = {
+        "vif_list_id",
+        "vif_id"
+};
+
 static int
 dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
 {
@@ -40,12 +53,13 @@ dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U
 	proto_tree *vntag_tree = NULL;
 	ethertype_data_t ethertype_data;
 
-	/* from scapy (http://hg.secdev.org/scapy-com/rev/37acec891993) GPLv2: */
-	/* another: http://www.definethecloud.net/access-layer-network-virtualization-vn-tag-and-vepa */
+	/* Documentation:
+	   https://d2zmdbbm9feqrf.cloudfront.net/2012/usa/pdf/BRKDCT-2340.pdf p.61
+	   http://www.definethecloud.net/access-layer-network-virtualization-vn-tag-and-vepa
+	 */
 	static const int * fields[] = {
 		&hf_vntag_dir,
 		&hf_vntag_ptr,
-		&hf_vntag_vif_list_id,
 		&hf_vntag_dst,
 		&hf_vntag_looped,
 		&hf_vntag_r,
@@ -66,8 +80,7 @@ dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U
 
 	encap_proto = tvb_get_ntohs(tvb, 4);
 
-	/* copied from packet-vlan.c do we need it also for VNTAG? */
-#if 0
+	/* VNTAG may also carry 802.2 encapsulated data */
 	if (encap_proto <= IEEE_802_3_MAX_LEN) {
 		gboolean is_802_2;
 
@@ -81,14 +94,13 @@ dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U
 		is_802_2 = TRUE;
 
 		/* Don't throw an exception for this check (even a BoundsError) */
-		if (tvb_captured_length_remaining(tvb, 4) >= 2) {
-			if (tvb_get_ntohs(tvb, 4) == 0xffff)
+		if (tvb_captured_length_remaining(tvb, 6) >= 2) {
+			if (tvb_get_ntohs(tvb, 6) == 0xffff)
 				is_802_2 = FALSE;
 		}
 
-		dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vntag_tree, hf_vntag_len, hf_vntag_trailer, 0);
+		dissect_802_3(encap_proto, is_802_2, tvb, 6, pinfo, tree, vntag_tree, hf_vntag_len, hf_vntag_trailer, &ei_vntag_len, 0);
 	} else {
-#endif
 		ethertype_data.etype = encap_proto;
 		ethertype_data.offset_after_ethertype = 6;
 		ethertype_data.fh_tree = vntag_tree;
@@ -97,9 +109,7 @@ dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U
 		ethertype_data.fcs_len = 0;
 
 		call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, &ethertype_data);
-#if 0
 	}
-#endif
 	return tvb_captured_length(tvb);
 }
 
@@ -111,19 +121,16 @@ proto_register_vntag(void)
 			{ "Type", "vntag.etype", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, NULL, HFILL }
 		},
 		{ &hf_vntag_dir,
-			{ "Direction", "vntag.dir", FT_UINT32, BASE_DEC, NULL, 0x80000000, NULL, HFILL }
+			{ "Direction", "vntag.dir", FT_BOOLEAN, 32, TFS(&vntag_dir_tfs), 0x80000000, NULL, HFILL }
 		},
 		{ &hf_vntag_ptr,
-			{ "Pointer", "vntag.ptr", FT_UINT32, BASE_DEC, NULL, 0x40000000, NULL, HFILL }
-		},
-		{ &hf_vntag_vif_list_id,
-			{ "Downlink Ports", "vntag.vif_list_id", FT_UINT32, BASE_DEC, NULL, 0x30000000, NULL, HFILL }
+			{ "Pointer", "vntag.ptr", FT_BOOLEAN, 32, TFS(&vntag_ptr_tfs), 0x40000000, NULL, HFILL }
 		},
 		{ &hf_vntag_dst,
-			{ "Destination", "vntag.dst", FT_UINT32, BASE_DEC, NULL, 0x0FFF0000, NULL, HFILL }
+			{ "Destination", "vntag.dst", FT_UINT32, BASE_DEC, NULL, 0x3FFF0000, NULL, HFILL }
 		},
 		{ &hf_vntag_looped,
-			{ "Looped", "vntag.looped", FT_UINT32, BASE_DEC, NULL, 0x00008000, NULL, HFILL }
+			{ "Looped", "vntag.looped", FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00008000, NULL, HFILL }
 		},
 		{ &hf_vntag_r,
 			{ "Reserved", "vntag.r", FT_UINT32, BASE_DEC, NULL, 0x00004000, NULL, HFILL }
@@ -134,12 +141,9 @@ proto_register_vntag(void)
 		{ &hf_vntag_src,
 			{ "Source", "vntag.src", FT_UINT32, BASE_DEC, NULL, 0x00000FFF, NULL, HFILL }
 		},
-
-#if 0
 		{ &hf_vntag_len,
 			{ "Length", "vntag.len", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }
 		},
-#endif
 		{ &hf_vntag_trailer,
 			{ "Trailer", "vntag.trailer", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }
 		}
@@ -149,9 +153,17 @@ proto_register_vntag(void)
 		&ett_vntag
 	};
 
+	static ei_register_info ei[] = {
+		{ &ei_vntag_len, { "vntag.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
+	};
+	expert_module_t* expert_vntag;
+
 	proto_vntag = proto_register_protocol("VN-Tag", "VNTAG", "vntag");
 	proto_register_field_array(proto_vntag, hf, array_length(hf));
 	proto_register_subtree_array(ett, array_length(ett));
+	expert_vntag = expert_register_protocol(proto_vntag);
+	expert_register_field_array(expert_vntag, ei, array_length(ei));
+
 }
 
 void
@@ -159,8 +171,6 @@ proto_reg_handoff_vntag(void)
 {
 	dissector_handle_t vntag_handle;
 
-	/* XXX, add 0x8926 define to epan/etypes.h && etype_vals */
-
 	vntag_handle = create_dissector_handle(dissect_vntag, proto_vntag);
 	dissector_add_uint("ethertype", ETHERTYPE_VNTAG, vntag_handle);