VXLAN: Add Group Based Policy dissector

According to some advices from my last commit,i made some changes, and i
use proto_tree_add_bitmask for bits field.

Editing VXLAN dissector for supporting GBP extension described in the
following draft link :
https://tools.ietf.org/html/draft-smith-vxlan-group-policy-00

This pach works fine with "old" version of VXLAN (no GBP support)

The flags are now extended to 16 bits to support GBP extension, Group
Policy Id is on 16 bits, VNI always on 24 bits and remaining bits are reserved.
The following bits are defined in addition to the existing VXLAN fields:
	bit 0 : "G" Group Based Policy Extension bit
	bit 9 : "D" Don't Learn bit
	bit 12 : "A" Policy Applied bit
	the remaining bits are reserved

Bug: 11348
Change-Id: I425ed63cf76f134eb3d1680a1753ed31f252dfa8
Signed-off-by: Amine Kherbouche <amine.kherbouche@6wind.com>
Reviewed-on: https://code.wireshark.org/review/9537
Reviewed-by: Alexis La Goutte <alexis.lagoutte@gmail.com>
Petri-Dish: Alexis La Goutte <alexis.lagoutte@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

1 files changed, 41 insertions, 60 deletions

diff --git a/epan/dissectors/packet-vxlan.c b/epan/dissectors/packet-vxlan.c
index d7ea55691f..ddadf99a58 100644
--- a/epan/dissectors/packet-vxlan.c
+++ b/epan/dissectors/packet-vxlan.c
@@ -28,6 +28,7 @@
 #include "config.h"
 
 #include <epan/packet.h>
+#include <epan/tfs.h>
 
 #define UDP_PORT_VXLAN  4789
 
@@ -37,15 +38,12 @@ void proto_reg_handoff_vxlan(void);
 static int proto_vxlan = -1;
 
 static int hf_vxlan_flags = -1;
-static int hf_vxlan_flag_b7 = -1;
-static int hf_vxlan_flag_b6 = -1;
-static int hf_vxlan_flag_b5 = -1;
-static int hf_vxlan_flag_b4 = -1;
+static int hf_vxlan_flags_reserved = -1;
+static int hf_vxlan_flag_a = -1;
+static int hf_vxlan_flag_d = -1;
 static int hf_vxlan_flag_i = -1;
-static int hf_vxlan_flag_b2 = -1;
-static int hf_vxlan_flag_b1 = -1;
-static int hf_vxlan_flag_b0 = -1;
-static int hf_vxlan_reserved_24 = -1;
+static int hf_vxlan_flag_g = -1;
+static int hf_vxlan_gbp = -1;
 static int hf_vxlan_vni = -1;
 static int hf_vxlan_reserved_8 = -1;
 
@@ -53,6 +51,14 @@ static int hf_vxlan_reserved_8 = -1;
 static int ett_vxlan = -1;
 static int ett_vxlan_flgs = -1;
 
+static const int *flags_fields[] = {
+        &hf_vxlan_flag_g,
+        &hf_vxlan_flag_d,
+        &hf_vxlan_flag_i,
+        &hf_vxlan_flag_a,
+        &hf_vxlan_flags_reserved,
+        NULL
+    };
 
 static dissector_handle_t eth_handle;
 
@@ -77,31 +83,24 @@ dissect_vxlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
             0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
         VXLAN Header:
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-           |R|R|R|R|I|R|R|R|            Reserved                           |
+           |G|R|R|R|I|R|R|R|R|D|R|R|A|R|R|R|        Group Policy ID        |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            |                VXLAN Network Identifier (VNI) |   Reserved    |
            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
-    /* Flags (8 bits) where the I flag MUST be set  to 1 for a valid
-     *    VXLAN Network ID (VNI).  The remaining 7 bits (designated "R") are
+    /* Flags (16 bits) where the I flag MUST be set  to 1 for a valid
+     *    VXLAN Network ID (VNI).  The remaining 12 bits (designated "R") are
      *    reserved fields and MUST be set to zero.
      */
-    flg_item = proto_tree_add_item(vxlan_tree, hf_vxlan_flags, tvb, offset, 1, ENC_BIG_ENDIAN);
+    flg_item = proto_tree_add_item(vxlan_tree, hf_vxlan_flags, tvb, offset, 2, ENC_BIG_ENDIAN);
     flg_tree = proto_item_add_subtree(flg_item, ett_vxlan_flgs);
 
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b7, tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b6, tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b5, tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b4, tvb, offset, 1, ENC_BIG_ENDIAN);
-
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_i,  tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b2, tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b1, tvb, offset, 1, ENC_BIG_ENDIAN);
-    proto_tree_add_item(flg_tree, hf_vxlan_flag_b0, tvb, offset, 1, ENC_BIG_ENDIAN);
-    offset++;
+    proto_tree_add_bitmask(flg_tree, tvb, offset, hf_vxlan_flags,
+        ett_vxlan_flgs, flags_fields, ENC_BIG_ENDIAN);
+    offset+=2;
 
-    proto_tree_add_item(vxlan_tree, hf_vxlan_reserved_24, tvb, offset, 3, ENC_BIG_ENDIAN);
-    offset+=3;
+    proto_tree_add_item(vxlan_tree, hf_vxlan_gbp, tvb, offset, 2, ENC_BIG_ENDIAN);
+    offset+=2;
 
     proto_tree_add_item(vxlan_tree, hf_vxlan_vni, tvb, offset, 3, ENC_BIG_ENDIAN);
     offset+=3;
@@ -123,61 +122,43 @@ proto_register_vxlan(void)
     static hf_register_info hf[] = {
         { &hf_vxlan_flags,
           { "Flags", "vxlan.flags",
-            FT_UINT8, BASE_HEX, NULL, 0x00,
+            FT_UINT16, BASE_HEX, NULL, 0x00,
             NULL, HFILL
           },
         },
-        { &hf_vxlan_flag_b7,
-          { "Reserved(R)", "vxlan.flag_b7",
-            FT_BOOLEAN, 8, NULL, 0x80,
-            NULL, HFILL,
-          },
-        },
-        { &hf_vxlan_flag_b6,
-          { "Reserved(R)", "vxlan.flag_b6",
-            FT_BOOLEAN, 8, NULL, 0x40,
+        { &hf_vxlan_flags_reserved,
+          { "Reserved(R)", "vxlan.flags_reserved",
+            FT_BOOLEAN, 16, NULL, 0x77b7,
             NULL, HFILL,
           },
         },
-        { &hf_vxlan_flag_b5,
-          { "Reserved(R)", "vxlan.flag_b5",
-            FT_BOOLEAN, 8, NULL, 0x20,
-            NULL, HFILL,
-          },
-        },
-        { &hf_vxlan_flag_b4,
-          { "Reserved(R)", "vxlan.flag_b4",
-            FT_BOOLEAN, 8, NULL, 0x10,
+        { &hf_vxlan_flag_g,
+          { "GBP Extension", "vxlan.flag_g",
+            FT_BOOLEAN, 16, TFS(&tfs_defined_not_defined), 0x8000,
             NULL, HFILL,
           },
         },
         { &hf_vxlan_flag_i,
-          { "VXLAN Network ID(VNI)", "vxlan.flag_i",
-            FT_BOOLEAN, 8, TFS(&tfs_present_not_present), 0x08,
-            NULL, HFILL,
-          },
-        },
-        { &hf_vxlan_flag_b2,
-          { "Reserved(R)", "vxlan.flag_b2",
-            FT_BOOLEAN, 8, NULL, 0x04,
+          { "VXLAN Network ID (VNI)", "vxlan.flag_i",
+            FT_BOOLEAN, 16, NULL, 0x0800,
             NULL, HFILL,
           },
         },
-        { &hf_vxlan_flag_b1,
-          { "Reserved(R)", "vxlan.flag_b1",
-            FT_BOOLEAN, 8, NULL, 0x02,
+        { &hf_vxlan_flag_d,
+          { "Don't Learn", "vxlan.flag_d",
+            FT_BOOLEAN, 16, NULL, 0x0040,
             NULL, HFILL,
           },
         },
-        { &hf_vxlan_flag_b0,
-          { "Reserved(R)", "vxlan.flag_b0",
-            FT_BOOLEAN, 8, NULL, 0x01,
+        { &hf_vxlan_flag_a,
+          { "Policy Applied", "vxlan.flag_a",
+            FT_BOOLEAN, 16, NULL, 0x0008,
             NULL, HFILL,
           },
         },
-        { &hf_vxlan_reserved_24,
-          { "Reserved", "vxlan.reserved24",
-            FT_UINT24, BASE_HEX, NULL, 0x00,
+        { &hf_vxlan_gbp,
+          { "Group Policy ID", "vxlan.gbp",
+            FT_UINT16, BASE_DEC, NULL, 0x00,
             NULL, HFILL
           },
         },