/* packet-usb.c * * $Id$ * * usb basic dissector * By Paolo Abeni * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include #include #include /* protocols and header fields */ static int proto_usb = -1; static int hf_usb_urb_type = -1; static int hf_usb_device_address = -1; static int hf_usb_endpoint_number = -1; static int hf_usb_src_endpoint_number = -1; static int hf_usb_dst_endpoint_number = -1; static int hf_usb_request = -1; static int hf_usb_value = -1; static int hf_usb_index = -1; static int hf_usb_length = -1; static int hf_usb_data = -1; static int hf_usb_setup_bmRequestType = -1; static int hf_usb_setup_bmRequestType_direction = -1; static int hf_usb_setup_bmRequestType_type = -1; static int hf_usb_setup_bmRequestType_recipient = -1; static int hf_usb_bDescriptorType = -1; static int hf_usb_descriptor_index = -1; static int hf_usb_language_id = -1; static int hf_usb_bLength = -1; static int hf_usb_bcdUSB = -1; static int hf_usb_bDeviceClass = -1; static int hf_usb_bDeviceSubClass = -1; static int hf_usb_bDeviceProtocol = -1; static int hf_usb_bMaxPacketSize0 = -1; static int hf_usb_idVendor = -1; static int hf_usb_idProduct = -1; static int hf_usb_bcdDevice = -1; static int hf_usb_iManufacturer = -1; static int hf_usb_iProduct = -1; static int hf_usb_iSerialNumber = -1; static int hf_usb_bNumConfigurations = -1; static gint usb_hdr = -1; static gint usb_setup_hdr = -1; static gint ett_usb_setup_bmrequesttype = -1; /* there is one such structure for each device/endpoint conversation */ typedef struct _usb_conv_info_t { emem_tree_t *transactions; } usb_conv_info_t; /* there is one such structure for each request/response */ typedef struct _usb_trans_info_t { guint32 request_in; guint32 response_in; guint8 requesttype; guint8 request; union { struct { guint8 type; guint8 index; } get_descriptor; }; } usb_trans_info_t; typedef enum { URB_CONTROL_INPUT, URB_CONTROL_OUTPUT, URB_ISOCHRONOUS_INPUT, URB_ISOCHRONOUS_OUTPUT, URB_INTERRUPT_INPUT, URB_INTERRUPT_OUTPUT, URB_BULK_INPUT, URB_BULK_OUTPUT, URB_UNKNOWN } urb_type_t; typedef struct usb_header { guint32 urb_type; guint32 device_address; guint32 endpoint_number; guint32 setup_packet; } usb_header_t; typedef struct usb_setup { guint8 bmRequestType; guint8 bRequest; guint16 wValue; guint16 wIndex; guint16 wLength; } usb_setup_t; static const value_string usb_urb_type_vals[] = { {URB_CONTROL_INPUT, "URB_CONTROL_INPUT"}, {URB_CONTROL_OUTPUT,"URB_CONTROL_OUTPUT"}, {URB_ISOCHRONOUS_INPUT,"URB_ISOCHRONOUS_INPUT"}, {URB_ISOCHRONOUS_OUTPUT,"URB_ISOCHRONOUS_OUTPUT"}, {URB_INTERRUPT_INPUT,"URB_INTERRUPT_INPUT"}, {URB_INTERRUPT_OUTPUT,"URB_INTERRUPT_OUTPUT"}, {URB_BULK_INPUT,"URB_BULK_INPUT"}, {URB_BULK_OUTPUT,"URB_BULK_OUTPUT"}, {URB_UNKNOWN, "URB_UNKNOWN"}, {0, NULL} }; #define USB_DT_DEVICE 1 #define USB_DT_CONFIGURATION 2 #define USB_DT_STRING 3 #define USB_DT_INTERFACE 4 #define USB_DT_ENDPOINT 5 #define USB_DT_DEVICE_QUALIFIER 6 #define USB_DT_OTHER_SPEED_CONFIGURATION 7 #define USB_DT_INTERFACE_POWER 8 static const value_string descriptor_type_vals[] = { {USB_DT_DEVICE, "DEVICE"}, {USB_DT_CONFIGURATION, "CONFIGURATION"}, {USB_DT_STRING, "STRING"}, {USB_DT_INTERFACE, "INTERFACE"}, {USB_DT_ENDPOINT, "ENDPOINT"}, {USB_DT_DEVICE_QUALIFIER, "DEVICE_QUALIFIER"}, {USB_DT_OTHER_SPEED_CONFIGURATION, "OTHER_SPEED_CONFIGURATION"}, {USB_DT_INTERFACE_POWER, "INTERFACE_POWER"}, {0,NULL} }; /* SETUP dissectors */ /* * This dissector is used to dissect the setup part and the data * for URB_CONTROL_INPUT / GET DESCRIPTOR */ static void dissect_usb_setup_get_descriptor(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb, int offset, gboolean is_request, usb_trans_info_t *usb_trans_info) { if(is_request){ switch(usb_trans_info->requesttype){ case 0x80: /* 9.4.3 */ /* descriptor type */ proto_tree_add_item(tree, hf_usb_bDescriptorType, tvb, offset, 1, FALSE); usb_trans_info->get_descriptor.type=tvb_get_guint8(tvb, offset); offset++; if (check_col(pinfo->cinfo, COL_INFO)) { col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str(usb_trans_info->get_descriptor.type, descriptor_type_vals, "Unknown type %x")); } /* descriptor index */ proto_tree_add_item(tree, hf_usb_descriptor_index, tvb, offset, 1, FALSE); usb_trans_info->get_descriptor.index=tvb_get_guint8(tvb, offset); offset++; /* language id */ proto_tree_add_item(tree, hf_usb_language_id, tvb, offset, 2, FALSE); offset+=2; /* length */ proto_tree_add_item(tree, hf_usb_length, tvb, offset, 2, FALSE); offset += 2; break; default: proto_tree_add_item(tree, hf_usb_value, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(tree, hf_usb_index, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(tree, hf_usb_length, tvb, offset, 2, FALSE); offset += 2; } } else { if (check_col(pinfo->cinfo, COL_INFO)) { col_append_fstr(pinfo->cinfo, COL_INFO, " %s", val_to_str(usb_trans_info->get_descriptor.type, descriptor_type_vals, "Unknown type %x")); } switch(usb_trans_info->get_descriptor.type){ case USB_DT_DEVICE: /* 9.6.1 */ /* bLength */ proto_tree_add_item(tree, hf_usb_bLength, tvb, offset, 1, FALSE); offset++; /* bDescriptorType */ proto_tree_add_item(tree, hf_usb_bDescriptorType, tvb, offset, 1, FALSE); offset++; /* bcdUSB */ proto_tree_add_item(tree, hf_usb_bcdUSB, tvb, offset, 2, FALSE); offset+=2; /* bDeviceClass */ proto_tree_add_item(tree, hf_usb_bDeviceClass, tvb, offset, 1, FALSE); offset++; /* bDeviceSubClass */ proto_tree_add_item(tree, hf_usb_bDeviceSubClass, tvb, offset, 1, FALSE); offset++; /* bDeviceProtocol */ proto_tree_add_item(tree, hf_usb_bDeviceProtocol, tvb, offset, 1, FALSE); offset++; /* bMaxPacketSize0 */ proto_tree_add_item(tree, hf_usb_bMaxPacketSize0, tvb, offset, 1, FALSE); offset++; /* idVendor */ proto_tree_add_item(tree, hf_usb_idVendor, tvb, offset, 2, FALSE); offset+=2; /* idProduct */ proto_tree_add_item(tree, hf_usb_idProduct, tvb, offset, 2, FALSE); offset+=2; /* bcdDevice */ proto_tree_add_item(tree, hf_usb_bcdDevice, tvb, offset, 2, FALSE); offset+=2; /* iManufacturer */ proto_tree_add_item(tree, hf_usb_iManufacturer, tvb, offset, 1, FALSE); offset++; /* iProduct */ proto_tree_add_item(tree, hf_usb_iProduct, tvb, offset, 1, FALSE); offset++; /* iSerialNumber */ proto_tree_add_item(tree, hf_usb_iSerialNumber, tvb, offset, 1, FALSE); offset++; /* bNumConfigurations */ proto_tree_add_item(tree, hf_usb_bNumConfigurations, tvb, offset, 1, FALSE); offset++; break; default: /* XXX dissect the descriptor coming back from the device */ proto_tree_add_text(tree, tvb, offset, tvb_length_remaining(tvb, offset), "get descriptor data..."); } } } typedef void (*usb_setup_dissector)(packet_info *pinfo, proto_tree *tree, tvbuff_t *tvb, int offset, gboolean is_request, usb_trans_info_t *usb_trans_info); typedef struct _usb_setup_dissector_table_t { guint8 request; usb_setup_dissector dissector; } usb_setup_dissector_table_t; #define USB_SETUP_GET_DESCRIPTOR 6 static const usb_setup_dissector_table_t setup_dissectors[] = { {USB_SETUP_GET_DESCRIPTOR, dissect_usb_setup_get_descriptor}, {0, NULL} }; static const value_string setup_request_names_vals[] = { {USB_SETUP_GET_DESCRIPTOR, "GET DESCRIPTOR"}, {0, NULL} }; static const true_false_string tfs_bmrequesttype_direction = { "Device-to-host", "Host-to-device" }; static const value_string bmrequesttype_type_vals[] = { {0, "Standard"}, {1, "Class"}, {2, "Vendor"}, {3, "Reserved"}, {0, NULL} }; static const value_string bmrequesttype_recipient_vals[] = { {0, "Device"}, {1, "Interface"}, {2, "Endpoint"}, {3, "Other"}, {0, NULL} }; static int dissect_usb_setup_bmrequesttype(proto_tree *parent_tree, tvbuff_t *tvb, int offset) { proto_item *item=NULL; proto_tree *tree=NULL; if(parent_tree){ item=proto_tree_add_item(parent_tree, hf_usb_setup_bmRequestType, tvb, offset, 1, FALSE); tree = proto_item_add_subtree(item, ett_usb_setup_bmrequesttype); } proto_tree_add_item(tree, hf_usb_setup_bmRequestType_direction, tvb, offset, 1, FALSE); proto_tree_add_item(tree, hf_usb_setup_bmRequestType_type, tvb, offset, 1, FALSE); proto_tree_add_item(tree, hf_usb_setup_bmRequestType_recipient, tvb, offset, 1, FALSE); offset++; return offset; } static void dissect_usb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent) { int offset = 0; int type, endpoint; gboolean setup; proto_tree *tree = NULL; static guint32 src_addr, dst_addr, tmp_addr; /* has to be static due to SET_ADDRESS */ guint32 src_port, dst_port; gboolean is_request; usb_conv_info_t *usb_conv_info; conversation_t *conversation; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "USB"); /* add usb hdr*/ if (parent) { proto_item *ti = NULL; ti = proto_tree_add_protocol_format(parent, proto_usb, tvb, 0, sizeof(usb_header_t), "USB URB"); tree = proto_item_add_subtree(ti, usb_hdr); } type = tvb_get_ntohl(tvb, offset); proto_tree_add_item(tree, hf_usb_urb_type, tvb, offset, 4, FALSE); offset += 4; if (check_col(pinfo->cinfo, COL_INFO)) { col_append_fstr(pinfo->cinfo, COL_INFO, "%s", val_to_str(type, usb_urb_type_vals, "Unknown type %x")); } #define USB_ADDR_LEN 4 proto_tree_add_item(tree, hf_usb_device_address, tvb, offset, 4, FALSE); tmp_addr=tvb_get_ntohl(tvb, offset); offset += 4; proto_tree_add_item(tree, hf_usb_endpoint_number, tvb, offset, 4, FALSE); endpoint=tvb_get_ntohl(tvb, offset); offset += 4; /* check for setup hdr presence */ setup = tvb_get_ntohl(tvb, offset); offset += 4; /* set up addresses and ports */ switch(type){ case URB_CONTROL_INPUT: /* CONTROL INPUT packets are requests if they contain a "setup" * blob and responses othervise */ if(setup){ src_addr=0xffffffff; dst_addr=tmp_addr; src_port=0xffff; dst_port=endpoint; is_request=TRUE; } else { src_addr=tmp_addr; dst_addr=0xffffffff; src_port=endpoint; dst_port=0xffff; is_request=FALSE; } break; default: /* dont know */ src_addr=0xffffffff; dst_addr=0xffffffff; src_port=0xffff; dst_port=0xffff; is_request=FALSE; } SET_ADDRESS(&pinfo->net_src, AT_USB, USB_ADDR_LEN, (char *)&src_addr); SET_ADDRESS(&pinfo->src, AT_USB, USB_ADDR_LEN, (char *)&src_addr); SET_ADDRESS(&pinfo->net_dst, AT_USB, USB_ADDR_LEN, (char *)&dst_addr); SET_ADDRESS(&pinfo->dst, AT_USB, USB_ADDR_LEN, (char *)&dst_addr); pinfo->ptype=PT_USB; pinfo->srcport=src_port; pinfo->destport=dst_port; /* * Do we have a conversation for this connection? */ conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0); if (conversation == NULL) { /* We don't yet have a conversation, so create one. */ conversation = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype, pinfo->srcport, pinfo->destport, 0); } /* do we have conversation specific data ? */ usb_conv_info = conversation_get_proto_data(conversation, proto_usb); if(!usb_conv_info){ /* no not yet so create some */ usb_conv_info = se_alloc(sizeof(usb_conv_info_t)); usb_conv_info->transactions=se_tree_create_non_persistent(EMEM_TREE_TYPE_RED_BLACK, "usb transactions"); conversation_add_proto_data(conversation, proto_usb, usb_conv_info); } switch(type){ case URB_CONTROL_INPUT: { const usb_setup_dissector_table_t *tmp; usb_setup_dissector dissector; proto_item *ti = NULL; proto_tree *setup_tree = NULL; guint8 requesttype, request; usb_trans_info_t *usb_trans_info; if(is_request){ /* this is a request */ ti = proto_tree_add_protocol_format(tree, proto_usb, tvb, offset, sizeof(usb_setup_t), "URB setup"); setup_tree = proto_item_add_subtree(ti, usb_setup_hdr); requesttype=tvb_get_guint8(tvb, offset); offset=dissect_usb_setup_bmrequesttype(setup_tree, tvb, offset); request=tvb_get_guint8(tvb, offset); proto_tree_add_item(setup_tree, hf_usb_request, tvb, offset, 1, FALSE); offset += 1; usb_trans_info=se_tree_lookup32(usb_conv_info->transactions, pinfo->fd->num); if(!usb_trans_info){ usb_trans_info=se_alloc(sizeof(usb_trans_info_t)); usb_trans_info->request_in=pinfo->fd->num; usb_trans_info->response_in=0; usb_trans_info->requesttype=requesttype; usb_trans_info->request=request; se_tree_insert32(usb_conv_info->transactions, pinfo->fd->num, usb_trans_info); } if (check_col(pinfo->cinfo, COL_INFO)) { col_clear(pinfo->cinfo, COL_INFO); col_append_fstr(pinfo->cinfo, COL_INFO, "%s Request", val_to_str(usb_trans_info->request, setup_request_names_vals, "Unknown type %x")); } dissector=NULL; for(tmp=setup_dissectors;tmp->dissector;tmp++){ if(tmp->request==request){ dissector=tmp->dissector; break; } } if(dissector){ dissector(pinfo, setup_tree, tvb, offset, is_request, usb_trans_info); offset+=6; } else { proto_tree_add_item(setup_tree, hf_usb_value, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(setup_tree, hf_usb_index, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(setup_tree, hf_usb_length, tvb, offset, 2, FALSE); offset += 2; } } else { /* this is a response */ if(pinfo->fd->flags.visited){ usb_trans_info=se_tree_lookup32(usb_conv_info->transactions, pinfo->fd->num); } else { usb_trans_info=se_tree_lookup32_le(usb_conv_info->transactions, pinfo->fd->num); if(usb_trans_info){ usb_trans_info->response_in=pinfo->fd->num; se_tree_insert32(usb_conv_info->transactions, pinfo->fd->num, usb_trans_info); } } if(usb_trans_info){ dissector=NULL; for(tmp=setup_dissectors;tmp->dissector;tmp++){ if(tmp->request==usb_trans_info->request){ dissector=tmp->dissector; break; } } if (check_col(pinfo->cinfo, COL_INFO)) { col_clear(pinfo->cinfo, COL_INFO); col_append_fstr(pinfo->cinfo, COL_INFO, "%s Response", val_to_str(usb_trans_info->request, setup_request_names_vals, "Unknown type %x")); } if(dissector){ dissector(pinfo, tree, tvb, offset, is_request, usb_trans_info); } } else { /* could not find a matching request */ } } return; } break; default: /* dont know */ ; } if (setup) { proto_item *ti = NULL; proto_tree *setup_tree = NULL; guint8 requesttype, request; ti = proto_tree_add_protocol_format(tree, proto_usb, tvb, offset, sizeof(usb_setup_t), "URB setup"); setup_tree = proto_item_add_subtree(ti, usb_setup_hdr); requesttype=tvb_get_guint8(tvb, offset); offset=dissect_usb_setup_bmrequesttype(setup_tree, tvb, offset); request=tvb_get_guint8(tvb, offset); proto_tree_add_item(setup_tree, hf_usb_request, tvb, offset, 1, FALSE); offset += 1; proto_tree_add_item(tree, hf_usb_value, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(tree, hf_usb_index, tvb, offset, 2, FALSE); offset += 2; proto_tree_add_item(tree, hf_usb_length, tvb, offset, 2, FALSE); offset += 2; } proto_tree_add_item(tree, hf_usb_data, tvb, offset, tvb_length_remaining(tvb, offset), FALSE); } void proto_register_usb(void) { static hf_register_info hf[] = { { &hf_usb_urb_type, { "URB type", "usb.urb_type", FT_UINT32, BASE_DEC, VALS(usb_urb_type_vals), 0x0, "URB type", HFILL }}, { &hf_usb_device_address, { "Device", "usb.device_address", FT_UINT32, BASE_DEC, NULL, 0x0, "USB device address", HFILL }}, { &hf_usb_endpoint_number, { "Endpoint", "usb.endpoint_number", FT_UINT32, BASE_HEX, NULL, 0x0, "usb endpoint number", HFILL }}, { &hf_usb_src_endpoint_number, { "Src Endpoint", "usb.src.endpoint", FT_UINT32, BASE_HEX, NULL, 0x0, "src usb endpoint number", HFILL }}, { &hf_usb_dst_endpoint_number, { "Dst Endpoint", "usb.dst.endpoint", FT_UINT32, BASE_HEX, NULL, 0x0, "dst usb endpoint number", HFILL }}, { &hf_usb_setup_bmRequestType, { "bmRequestType", "usb.setup.bmRequestType", FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_request, { "bRequest", "usb.setup.bRequest", FT_UINT8, BASE_HEX, VALS(setup_request_names_vals), 0x0, "", HFILL }}, { &hf_usb_value, { "wValue", "usb.setup.wValue", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_index, { "wIndex", "usb.setup.wIndex", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_length, { "wLength", "usb.setup.wLength", FT_UINT16, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_data, {"Application Data", "usb.data", FT_BYTES, BASE_HEX, NULL, 0x0, "Payload is application data", HFILL }}, { &hf_usb_setup_bmRequestType_direction, { "Direction", "usb.setup.bmRequestType.direction", FT_BOOLEAN, 8, TFS(&tfs_bmrequesttype_direction), 0x80, "", HFILL }}, { &hf_usb_setup_bmRequestType_type, { "Type", "usb.setup.bmRequestType.type", FT_UINT8, BASE_HEX, VALS(bmrequesttype_type_vals), 0x70, "", HFILL }}, { &hf_usb_setup_bmRequestType_recipient, { "Recipient", "usb.setup.bmRequestType.recipient", FT_UINT8, BASE_HEX, VALS(bmrequesttype_recipient_vals), 0x0f, "", HFILL }}, { &hf_usb_bDescriptorType, { "bDescriptorType", "usb.bDescriptorType", FT_UINT8, BASE_HEX, VALS(descriptor_type_vals), 0x0, "", HFILL }}, { &hf_usb_descriptor_index, { "Descriptor Index", "usb.DescriptorIndex", FT_UINT8, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_language_id, { "Language Id", "usb.LanguageId", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_bLength, { "bLength", "usb.bLength", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_bcdUSB, { "bcdUSB", "usb.bcdUSB", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_bDeviceClass, { "bDeviceClass", "usb.bDeviceClass", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_bDeviceSubClass, { "bDeviceSubClass", "usb.bDeviceSubClass", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_bDeviceProtocol, { "bDeviceProtocol", "usb.bDeviceProtocol", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_bMaxPacketSize0, { "bMaxPacketSize0", "usb.bMaxPacketSize0", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_idVendor, { "idVendor", "usb.idVendor", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_idProduct, { "idProduct", "usb.idProduct", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_bcdDevice, { "bcdDevice", "usb.bcdDevice", FT_UINT16, BASE_HEX, NULL, 0x0, "", HFILL }}, { &hf_usb_iManufacturer, { "iManufacturer", "usb.iManufacturer", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_iProduct, { "iProduct", "usb.iProduct", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_iSerialNumber, { "iSerialNumber", "usb.iSerialNumber", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_usb_bNumConfigurations, { "bNumConfigurations", "usb.bNumConfigurations", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }}, }; static gint *usb_subtrees[] = { &usb_hdr, &usb_setup_hdr, &ett_usb_setup_bmrequesttype }; proto_usb = proto_register_protocol("USB", "USB", "usb"); proto_register_field_array(proto_usb, hf, array_length(hf)); proto_register_subtree_array(usb_subtrees, array_length(usb_subtrees)); register_dissector("usb", dissect_usb, proto_usb); } void proto_reg_handoff_usb(void) { dissector_handle_t usb_handle; usb_handle = create_dissector_handle(dissect_usb, proto_usb); dissector_add("wtap_encap", WTAP_ENCAP_USB, usb_handle); }