USB: Fall back to transfer type from descriptor

When dissecting USBIP packets, the transfer type is not known for every
packet like when dissecting usbmon captures. This patch lifs the
transfer type for the endpoint in the device descriptor and stores it in
the conversation. If the per-packet transfer type is unknown for a
transfer, it tries the one from the descriptor instead. This enables
bulk/iso payload dissectors to work on USBIP packets too.

Change-Id: If0a3e4f3b9598f586fa460d0d07032d22e203122
Reviewed-on: https://code.wireshark.org/review/28412
Reviewed-by: Jaap Keuter <jaap.keuter@xs4all.nl>
Petri-Dish: Jaap Keuter <jaap.keuter@xs4all.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 32 insertions, 3 deletions

diff --git a/epan/dissectors/packet-usb.c b/epan/dissectors/packet-usb.c
index c0761482f6..ba4ebdcd98 100644
--- a/epan/dissectors/packet-usb.c
+++ b/epan/dissectors/packet-usb.c
@@ -1670,6 +1670,7 @@ get_usb_conv_info(conversation_t *conversation)
         usb_conv_info->deviceProduct     = DEV_PRODUCT_UNKNOWN;
         usb_conv_info->alt_settings      = wmem_array_new(wmem_file_scope(), sizeof(usb_alt_setting_t));
         usb_conv_info->transactions      = wmem_tree_new(wmem_file_scope());
+        usb_conv_info->descriptor_transfer_type = URB_UNKNOWN;
 
         conversation_add_proto_data(conversation, proto_usb, usb_conv_info);
     }
@@ -2385,6 +2386,7 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree,
     guint8            ep_type;
     guint8            len;
     usb_trans_info_t *usb_trans_info = NULL;
+    conversation_t   *conversation   = NULL;
 
     if (usb_conv_info)
         usb_trans_info = usb_conv_info->usb_trans_info;
@@ -2408,8 +2410,6 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree,
      * usb_conv_info structure.
      */
     if ((!pinfo->fd->flags.visited) && usb_trans_info && usb_trans_info->interface_info) {
-        conversation_t *conversation = NULL;
-
         if (pinfo->destport == NO_ENDPOINT) {
             address tmp_addr;
             usb_address_t *usb_addr = wmem_new0(wmem_packet_scope(), usb_address_t);
@@ -2444,6 +2444,30 @@ dissect_usb_endpoint_descriptor(packet_info *pinfo, proto_tree *parent_tree,
     }
     offset += 1;
 
+    if (conversation) {
+        usb_conv_info_t* endpoint_conv_info = get_usb_conv_info(conversation);
+        guint8 transfer_type;
+
+        switch(ep_type) {
+        case ENDPOINT_TYPE_CONTROL:
+            transfer_type = URB_CONTROL;
+            break;
+        case ENDPOINT_TYPE_ISOCHRONOUS:
+            transfer_type = URB_ISOCHRONOUS;
+            break;
+        case ENDPOINT_TYPE_BULK:
+            transfer_type = URB_BULK;
+            break;
+        case ENDPOINT_TYPE_INTERRUPT:
+            transfer_type = URB_INTERRUPT;
+            break;
+        default:
+            transfer_type = URB_UNKNOWN;
+            break;
+        }
+        endpoint_conv_info->descriptor_transfer_type = transfer_type;
+    }
+
     /* wMaxPacketSize */
     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);
@@ -3316,6 +3340,7 @@ try_dissect_next_protocol(proto_tree *tree, tvbuff_t *next_tvb, packet_info *pin
     /* if we select the next dissector based on a class,
        this is the (device or interface) class we're using */
     guint32                  usb_class;
+    guint8                   transfer_type;
 
     if (!usb_conv_info) {
         /*
@@ -3372,7 +3397,11 @@ try_dissect_next_protocol(proto_tree *tree, tvbuff_t *next_tvb, packet_info *pin
                     return tvb_captured_length(next_tvb);
     }
 
-    switch(usb_conv_info->transfer_type) {
+    transfer_type = usb_conv_info->transfer_type;
+    if (transfer_type == URB_UNKNOWN)
+        transfer_type = usb_conv_info->descriptor_transfer_type;
+
+    switch(transfer_type) {
         case URB_BULK:
             heur_subdissector_list = heur_bulk_subdissector_list;
             usb_dissector_table = usb_bulk_dissector_table;