From Steve Magnani:

Add decoding of fields within endpoint descriptor wMaxPacketSize

https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=7206

svn path=/trunk/; revision=42286

1 files changed, 31 insertions, 2 deletions

diff --git a/epan/dissectors/packet-usb.c b/epan/dissectors/packet-usb.c
index 69b366338a..12e399e545 100644
--- a/epan/dissectors/packet-usb.c
+++ b/epan/dissectors/packet-usb.c
@@ -118,6 +118,8 @@ static int hf_usb_bEndpointAttributeTransfer = -1;
 static int hf_usb_bEndpointAttributeSynchonisation = -1;
 static int hf_usb_bEndpointAttributeBehaviour = -1;
 static int hf_usb_wMaxPacketSize = -1;
+static int hf_usb_wMaxPacketSize_size = -1;
+static int hf_usb_wMaxPacketSize_slots = -1;
 static int hf_usb_bInterval = -1;
 static int hf_usb_wTotalLength = -1;
 static int hf_usb_bNumInterfaces = -1;
@@ -149,6 +151,7 @@ static gint ett_descriptor_device = -1;
 static gint ett_configuration_bmAttributes = -1;
 static gint ett_configuration_bEndpointAddress = -1;
 static gint ett_endpoint_bmAttributes = -1;
+static gint ett_endpoint_wMaxPacketSize = -1;
 
 static const int *usb_endpoint_fields[] = {
     &hf_usb_endpoint_direction,
@@ -465,6 +468,14 @@ static const value_string usb_bmAttributes_behaviour_vals[] = {
     {0,NULL}
 };
 
+static const value_string usb_wMaxPacketSize_slots_vals[]  = {
+    {0x00,      "1"},
+    {0x01,      "2"},
+    {0x02,      "3"},
+    {0x03,      "Reserved"},
+    {0,NULL}
+};
+
 /* from linux/include/asm-generic/errno.h */
 #define EPERM            1      /* Operation not permitted */
 #define ENOENT           2      /* No such file or directory */
@@ -1129,8 +1140,11 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree, tvb
     proto_tree *tree=NULL;
     proto_item *ep_attrib_item=NULL;
     proto_tree *ep_attrib_tree=NULL;
+    proto_item *ep_pktsize_item;
+    proto_tree *ep_pktsize_tree;
     int old_offset=offset;
     guint8 endpoint;
+    guint8 ep_type;
     guint8 len;
 
     if(parent_tree){
@@ -1185,6 +1199,7 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree, tvb
     }
 
     /* bmAttributes */
+    ep_type = ENDPOINT_TYPE(tvb_get_guint8(tvb, offset));
     if (tree) {
         ep_attrib_item=proto_tree_add_item(tree, hf_usb_bmAttributes, tvb, offset, 1, ENC_LITTLE_ENDIAN);
         ep_attrib_tree=proto_item_add_subtree(ep_attrib_item, ett_endpoint_bmAttributes);
@@ -1197,7 +1212,12 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree, tvb
     offset++;
 
     /* wMaxPacketSize */
-    proto_tree_add_item(tree, hf_usb_wMaxPacketSize, tvb, offset, 2, ENC_LITTLE_ENDIAN);
+    ep_pktsize_item = proto_tree_add_item(tree, hf_usb_wMaxPacketSize, tvb, offset, 2, ENC_LITTLE_ENDIAN);
+    ep_pktsize_tree = proto_item_add_subtree(ep_pktsize_item, ett_endpoint_wMaxPacketSize);
+	if ((ep_type == ENDPOINT_TYPE_INTERRUPT) || (ep_type == ENDPOINT_TYPE_ISOCHRONOUS)) {
+        proto_tree_add_item(ep_pktsize_tree, hf_usb_wMaxPacketSize_slots, tvb, offset, 2, ENC_LITTLE_ENDIAN);
+    }
+    proto_tree_add_item(ep_pktsize_tree, hf_usb_wMaxPacketSize_size, tvb, offset, 2, ENC_LITTLE_ENDIAN);
     offset+=2;
 
     /* bInterval */
@@ -2859,6 +2879,14 @@ proto_register_usb(void)
           { "wMaxPacketSize", "usb.wMaxPacketSize", FT_UINT16, BASE_DEC,
             NULL, 0x0, NULL, HFILL }},
 
+        { &hf_usb_wMaxPacketSize_size,
+          { "Maximum Packet Size", "usb.wMaxPacketSize.size", FT_UINT16, BASE_DEC,
+            NULL, 0x3FF, NULL, HFILL }},
+
+        { &hf_usb_wMaxPacketSize_slots,
+          { "Transactions per microframe", "usb.wMaxPacketSize.slots", FT_UINT16, BASE_DEC,
+            VALS(usb_wMaxPacketSize_slots_vals), (3<<11), NULL, HFILL }},
+
         { &hf_usb_bInterval,
           { "bInterval", "usb.bInterval", FT_UINT8, BASE_DEC,
             NULL, 0x0, NULL, HFILL }},
@@ -2949,7 +2977,8 @@ proto_register_usb(void)
         &ett_descriptor_device,
         &ett_configuration_bmAttributes,
         &ett_configuration_bEndpointAddress,
-        &ett_endpoint_bmAttributes
+        &ett_endpoint_bmAttributes,
+        &ett_endpoint_wMaxPacketSize
     };