MAUSB dissector uses USB addresses

The MAUSB dissector now prints the USB address for MAUSB data packets
in the Source & Destination columns. Before, the IP address was
printed.

All MAUSB data packets are now part of USB Conversations. Like the
USB dissector, all data to & from one endpoint are part of the same
conversation.

Issues that need to be resolved:
- In the case where multiple MAUSB packets exist in one TCP packet,
  only one USB address can be printed.
- The USB conversations do not appear in the conversations window.
  They should appear under the USB conversations tab.

Change-Id: I042daf7889cf70b3bbc450f9ccd974a0f93f4798
Reviewed-on: https://code.wireshark.org/review/1943
Reviewed-by: Evan Huus <eapache@gmail.com>

epan/dissectors/packet-mausb.c

@@ -326,6 +326,11 @@ static const value_string mausb_type_string[] = {
 #define MAUSB_EP_HANDLE_DEV_ADDR 0x0fe0
 #define MAUSB_EP_HANDLE_BUS_NUM  0xf000
 
+#define MAUSB_EP_HANDLE_D_OFFSET        0
+#define MAUSB_EP_HANDLE_EP_NUM_OFFSET   1
+#define MAUSB_EP_HANDLE_DEV_ADDR_OFFSET 5
+#define MAUSB_EP_HANDLE_BUS_NUM_OFFSET  12
+
 static const value_string mausb_status_string[] = {
     {   0, "SUCCESS (NO_ERROR)" },
     { 128, "UNSUCCESSFUL" },
@@ -515,6 +520,16 @@ static gboolean mausb_is_data_pkt(struct mausb_header *header)
     return MAUSB_PKT_TYPE_DATA == (header->type & MAUSB_PKT_TYPE_MASK);
 }
 
+/*** EP Handle parsing helper functions */
+
+static guint8 mausb_ep_handle_ep_num(guint16 handle) {
+    return (handle & MAUSB_EP_HANDLE_EP_NUM) >> MAUSB_EP_HANDLE_EP_NUM_OFFSET;
+}
+
+static guint8 mausb_ep_handle_dev_addr(guint16 handle) {
+    return (handle & MAUSB_EP_HANDLE_DEV_ADDR) >> MAUSB_EP_HANDLE_DEV_ADDR_OFFSET;
+}
+
 /* returns the length field of the MAUSB packet */
 static guint mausb_get_pkt_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset)
 {
@@ -876,6 +891,30 @@ static guint16 dissect_mausb_mgmt_pkt_flds(struct mausb_header *header,
     return offset;
 }
 
+static conversation_t
+*get_mausb_conversation(packet_info *pinfo, guint16 handle,
+                        gboolean is_data, gboolean req)
+{
+    conversation_t *conversation;
+    static usb_address_t  src_addr, dst_addr; /* has to be static due to SET_ADDRESS */
+    guint16 device_address;
+    int endpoint;
+
+    /* Treat data packets the same as URBs */
+    if (is_data) {
+        device_address = mausb_ep_handle_dev_addr(handle);
+        endpoint = mausb_ep_handle_ep_num(handle);
+
+        usb_set_addr(pinfo, &src_addr, &dst_addr, device_address, endpoint,
+                     req);
+        conversation = get_usb_conversation(pinfo, &pinfo->src, &pinfo->dst,
+                                            pinfo->srcport, pinfo->destport);
+    }
+    /* TODO: track control & managment packet conversations */
+
+    return conversation;
+}
+
 /* Used to detect multiple MA Packets in a single TCP packet */
 /* Not used for MA Packets in SNAP Packets */
 static gint mausb_num_pdus = 0;
@@ -961,6 +1000,8 @@ dissect_mausb_pkt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 
     /* Is the next field a device handle or an endpoint handle */
     header.handle = tvb_get_letohs(tvb, offset);
+    get_mausb_conversation(pinfo, header.handle, mausb_is_data_pkt(&header),
+                                                  mausb_is_from_host(&header));
 
     if (mausb_is_mgmt_pkt(&header)) {
 

epan/dissectors/packet-usb.c

@@ -1055,7 +1055,7 @@ get_usb_conv_info(conversation_t *conversation)
     return usb_conv_info;
 }
 
-static conversation_t *
+conversation_t *
 get_usb_conversation(packet_info *pinfo,
                      address *src_addr, address *dst_addr,
                      guint32 src_endpoint, guint32 dst_endpoint)
@@ -2654,7 +2654,7 @@ dissect_win32_usb_pseudo_header(tvbuff_t *tvb, packet_info *pinfo, proto_tree *t
 }
 
 /* Set the usb_address_t fields based on the direction of the urb */
-static void
+void
 usb_set_addr(packet_info *pinfo, usb_address_t *src_addr,
              usb_address_t *dst_addr, guint16 device_address, int endpoint,
              gboolean req)

epan/dissectors/packet-usb.h

@@ -24,6 +24,7 @@
 
 #include <epan/value_string.h>
 #include <epan/wmem/wmem.h>
+#include <epan/conversation.h>
 
 typedef struct _usb_address_t {
     guint32 device;
@@ -194,6 +195,11 @@ typedef struct _usb_tap_data_t {
 #define ENDPOINT_TYPE_BULK              2
 #define ENDPOINT_TYPE_INTERRUPT         3
 
+conversation_t *
+get_usb_conversation(packet_info *pinfo,
+                     address *src_addr, address *dst_addr,
+                     guint32 src_endpoint, guint32 dst_endpoint);
+
 usb_conv_info_t *get_usb_iface_conv_info(packet_info *pinfo, guint8 interface_num);
 
 proto_item * dissect_usb_descriptor_header(proto_tree *tree,
@@ -212,4 +218,10 @@ dissect_usb_unknown_descriptor(packet_info *pinfo _U_, proto_tree *parent_tree,
                                tvbuff_t *tvb, int offset,
                                usb_trans_info_t *usb_trans_info _U_,
                                usb_conv_info_t  *usb_conv_info _U_);
+
+void
+usb_set_addr(packet_info *pinfo, usb_address_t *src_addr,
+             usb_address_t *dst_addr, guint16 device_address, int endpoint,
+             gboolean req);
+
 #endif