diff --git a/src/usb/osmo_libusb.c b/src/usb/osmo_libusb.c
index fda9573..5b012b8 100644
--- a/src/usb/osmo_libusb.c
+++ b/src/usb/osmo_libusb.c
@@ -1,6 +1,6 @@
 /* libosmocore integration with libusb-1.0
  *
- * (C) 2019 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2019-2019 by Harald Welte <laforge@gnumonks.org>
  * All Rights Reserved.
  *
  * SPDX-License-Identifier: GPL-2.0+
@@ -33,6 +33,8 @@
 
 #include <libusb.h>
 
+#include <osmocom/usb/libusb.h>
+
 /***********************************************************************
  * logging integration
  ***********************************************************************/
@@ -104,7 +106,381 @@
 	talloc_free(ofd);
 }
 
+/***********************************************************************
+ * utility functions
+ ***********************************************************************/
 
+/*! obtain the string representation of the USB device path of given device.
+ *  \param[out] buf Output string buffer
+ *  \param[in] bufsize Size of output string buffer in bytes
+ *  \param[in] dev USB device whose bus path we want to obtain
+ *  \returns pointer to 'buf' in case of success; NULL in case of error */
+char *osmo_libusb_dev_get_path_buf(char *buf, size_t bufsize, libusb_device *dev)
+{
+#if (defined(LIBUSB_API_VERSION) && LIBUSB_API_VERSION >= 0x01000102) || \
+    (defined(LIBUSBX_API_VERSION) && LIBUSBX_API_VERSION >= 0x01000102)
+	struct osmo_strbuf sb = { .buf = buf, .len = bufsize };
+	uint8_t path[8];
+	int r,j;
+	r = libusb_get_port_numbers(dev, path, sizeof(path));
+	if (r > 0) {
+		OSMO_STRBUF_PRINTF(sb, "%d-%d", libusb_get_bus_number(dev), path[0]);
+		for (j = 1; j < r; j++){
+			OSMO_STRBUF_PRINTF(sb, ".%d", path[j]);
+		}
+	}
+	return buf;
+#else
+# warning "libusb too old - building without USB path support!"
+	return NULL;
+#endif
+}
+
+/*! obtain the string representation of the USB device path of given device.
+ *  \param[in] talloc context from which to dynamically allocate output string buffer
+ *  \param[in] dev USB device whose bus path we want to obtain
+ *  \returns pointer to 'buf' in case of success; NULL in case of error */
+char *osmo_libusb_dev_get_path_c(void *ctx, libusb_device *dev)
+{
+	char *buf = talloc_zero_size(ctx, USB_MAX_PATH_LEN);
+	if (!buf)
+		return NULL;
+	return osmo_libusb_dev_get_path_buf(buf, USB_MAX_PATH_LEN, dev);
+}
+
+static int match_dev_id(const struct libusb_device_descriptor *desc, const struct dev_id *id)
+{
+	if ((desc->idVendor == id->vendor_id) && (desc->idProduct == id->product_id))
+		return 1;
+	return 0;
+}
+
+static int match_dev_ids(const struct libusb_device_descriptor *desc, const struct dev_id *ids)
+{
+	const struct dev_id *id;
+
+	for (id = ids; id->vendor_id || id->product_id; id++) {
+		if (match_dev_id(desc, id))
+			return 1;
+	}
+	return 0;
+}
+
+/*! Find USB devices matching the specified list of USB VendorID/ProductIDs
+ *  \param[in] ctx talloc context from which to allocate output data
+ *  \param[in] luctx libusb context on which to operate
+ *  \param[in] dev_ids zero-terminated array of VendorId/ProductId tuples
+ *  \returns array of up to 256 libusb_device pointers; NULL in case of error */
+libusb_device **osmo_libusb_find_matching_usb_devs(void *ctx, struct libusb_context *luctx,
+						   const struct dev_id *dev_ids)
+{
+	libusb_device **list;
+	libusb_device **out = talloc_zero_array(ctx, libusb_device *, 256);
+	libusb_device **cur = out;
+	unsigned int i;
+	int rc;
+
+	if (!out)
+		return NULL;
+
+	rc = libusb_get_device_list(luctx, &list);
+	if (rc <= 0) {
+		perror("No USB devices found");
+		talloc_free(out);
+		return NULL;
+	}
+
+	for (i = 0; list[i] != NULL; i++) {
+		struct libusb_device_descriptor dev_desc;
+		libusb_device *dev = list[i];
+
+		rc = libusb_get_device_descriptor(dev, &dev_desc);
+		if (rc < 0) {
+			perror("Couldn't get device descriptor\n");
+			libusb_unref_device(dev);
+			continue;
+		}
+
+		if (match_dev_ids(&dev_desc, dev_ids)) {
+			*cur = dev;
+			cur++;
+			/* overflow check */
+			if (cur >= out + 256)
+				break;
+		} else
+			libusb_unref_device(dev);
+	}
+	if (cur == out) {
+		libusb_free_device_list(list, 1);
+		talloc_free(out);
+		return NULL;
+	}
+
+	libusb_free_device_list(list, 0);
+	return out;
+}
+
+/*! find a matching interface among all interfaces of the given USB device.
+ *  \param[in] dev USB device in which we shall search
+ *  \param[in] class USB Interface Class to look for
+ *  \param[in] sub_class USB Interface Subclass to look for
+ *  \param[in] protocol USB Interface Protocol to look for
+ *  \param[out] out User-allocated array for storing matches
+ *  \param[in] out_len Length of out array
+ *  \returns number of matching interfaces; negative in case of error */
+int osmo_libusb_dev_find_matching_interfaces(libusb_device *dev, int class, int sub_class,
+					     int protocol, struct usb_interface_match *out,
+					     unsigned int out_len)
+{
+	struct libusb_device_descriptor dev_desc;
+	int rc, i, out_idx = 0;
+	uint8_t addr;
+	char pathbuf[USB_MAX_PATH_LEN];
+	char *path;
+
+	rc = libusb_get_device_descriptor(dev, &dev_desc);
+	if (rc < 0) {
+		perror("Couldn't get device descriptor\n");
+		return -EIO;
+	}
+
+	addr = libusb_get_device_address(dev);
+	path = osmo_libusb_dev_get_path_buf(pathbuf, sizeof(pathbuf), dev);
+
+	/* iterate over all configurations */
+	for (i = 0; i < dev_desc.bNumConfigurations; i++) {
+		struct libusb_config_descriptor *conf_desc;
+		int j;
+
+		rc = libusb_get_config_descriptor(dev, i, &conf_desc);
+		if (rc < 0) {
+			fprintf(stderr, "Couldn't get config descriptor %u\n", i);
+			continue;
+		}
+		/* iterate over all interfaces */
+		for (j = 0; j < conf_desc->bNumInterfaces; j++) {
+			const struct libusb_interface *intf = &conf_desc->interface[j];
+			int k;
+			/* iterate over all alternate settings */
+			for (k = 0; k < intf->num_altsetting; k++) {
+				const struct libusb_interface_descriptor *if_desc;
+				if_desc = &intf->altsetting[k];
+				if (class >= 0 && if_desc->bInterfaceClass != class)
+					continue;
+				if (sub_class >= 0 && if_desc->bInterfaceSubClass != sub_class)
+					continue;
+				if (protocol >= 0 && if_desc->bInterfaceProtocol != protocol)
+					continue;
+				/* MATCH! */
+				out[out_idx].usb_dev = dev;
+				out[out_idx].vendor = dev_desc.idVendor;
+				out[out_idx].product = dev_desc.idProduct;
+				out[out_idx].addr = addr;
+				strncpy(out[out_idx].path, path, sizeof(out[out_idx].path)-1);
+				out[out_idx].path[sizeof(out[out_idx].path)-1] = '\0';
+				out[out_idx].configuration = conf_desc->bConfigurationValue;
+				out[out_idx].interface = if_desc->bInterfaceNumber;
+				out[out_idx].altsetting = if_desc->bAlternateSetting;
+				out[out_idx].class = if_desc->bInterfaceClass;
+				out[out_idx].sub_class = if_desc->bInterfaceSubClass;
+				out[out_idx].protocol = if_desc->bInterfaceProtocol;
+				out[out_idx].string_idx = if_desc->iInterface;
+				out_idx++;
+				if (out_idx >= out_len)
+					return out_idx;
+			}
+		}
+	}
+	return out_idx;
+}
+
+/*! find matching interfaces among a list devices of specified VendorId/ProductID tuples.
+ *  \param[in] luctx libusb context on which to operate
+ *  \param[in] dev_ids zero-terminated array of VendorId/ProductId tuples
+ *  \param[in] class USB Interface Class to look for
+ *  \param[in] sub_class USB Interface Subclass to look for
+ *  \param[in] protocol USB Interface Protocol to look for
+ *  \param[out] out User-allocated array for storing matches
+ *  \param[in] out_len Length of out array
+ *  \returns number of matching interfaces; negative in case of error */
+int osmo_libusb_find_matching_interfaces(libusb_context *luctx, const struct dev_id *dev_ids,
+					 int class, int sub_class, int protocol,
+					 struct usb_interface_match *out, unsigned int out_len)
+{
+	struct usb_interface_match *out_cur = out;
+	unsigned int out_len_remain = out_len;
+	libusb_device **list;
+	libusb_device **dev;
+
+	list = osmo_libusb_find_matching_usb_devs(NULL, luctx, dev_ids);
+	if (!list)
+		return 0;
+
+	for (dev = list; *dev; dev++) {
+		int rc;
+
+#if 0
+		struct libusb_device_descriptor dev_desc;
+		uint8_t ports[8];
+		uint8_t addr;
+		rc = libusb_get_device_descriptor(*dev, &dev_desc);
+		if (rc < 0) {
+			perror("Cannot get device descriptor");
+			continue;
+		}
+
+		addr = libusb_get_device_address(*dev);
+
+		rc = libusb_get_port_numbers(*dev, ports, sizeof(ports));
+		if (rc < 0) {
+			perror("Cannot get device path");
+			continue;
+		}
+
+		printf("Found USB Device %04x:%04x at address %d\n",
+			dev_desc.idVendor, dev_desc.idProduct, addr);
+#endif
+
+		rc = osmo_libusb_dev_find_matching_interfaces(*dev, class, sub_class,
+							      protocol, out_cur, out_len_remain);
+		if (rc < 0)
+			continue;
+		out_cur += rc;
+		out_len_remain -= rc;
+
+	}
+
+	/* unref / free list */
+	for (dev = list; *dev; dev++)
+		libusb_unref_device(*dev);
+	talloc_free(list);
+
+	return out_len - out_len_remain;
+}
+
+/*! open matching USB device and claim interface
+ *  \param[in] ctx talloc context to use for related allocations
+ *  \param[in] luctx libusb context on which to operate
+ *  \param[in] ifm interface match describing interface to claim
+ *  \returns libusb device chandle on success; NULL on error */
+libusb_device_handle *osmo_libusb_open_claim_interface(void *ctx, libusb_context *luctx,
+							const struct usb_interface_match *ifm)
+{
+	int rc, config;
+	struct dev_id dev_ids[] = { { ifm->vendor, ifm->product }, { 0, 0 } };
+	libusb_device **list;
+	libusb_device **dev;
+	libusb_device_handle *usb_devh = NULL;
+
+	list = osmo_libusb_find_matching_usb_devs(ctx, luctx, dev_ids);
+	if (!list) {
+		perror("No USB device with matching VID/PID");
+		return NULL;
+	}
+
+	for (dev = list; *dev; dev++) {
+		int addr;
+		char pathbuf[USB_MAX_PATH_LEN];
+		char *path;
+
+		addr = libusb_get_device_address(*dev);
+		path = osmo_libusb_dev_get_path_buf(pathbuf, sizeof(pathbuf), *dev);
+		if ((ifm->addr && addr == ifm->addr) ||
+		    (strlen(ifm->path) && !strcmp(path, ifm->path))) {
+			rc = libusb_open(*dev, &usb_devh);
+			if (rc < 0) {
+				fprintf(stderr, "Cannot open device: %s\n", libusb_error_name(rc));
+				usb_devh = NULL;
+				break;
+			}
+			rc = libusb_get_configuration(usb_devh, &config);
+			if (rc < 0) {
+				fprintf(stderr, "Cannot get current configuration: %s\n", libusb_error_name(rc));
+				libusb_close(usb_devh);
+				usb_devh = NULL;
+				break;
+			}
+			if (config != ifm->configuration) {
+				rc = libusb_set_configuration(usb_devh, ifm->configuration);
+				if (rc < 0) {
+					fprintf(stderr, "Cannot set configuration: %s\n", libusb_error_name(rc));
+					libusb_close(usb_devh);
+					usb_devh = NULL;
+					break;
+				}
+			}
+			rc = libusb_claim_interface(usb_devh, ifm->interface);
+			if (rc < 0) {
+				fprintf(stderr, "Cannot claim interface: %s\n", libusb_error_name(rc));
+				libusb_close(usb_devh);
+				usb_devh = NULL;
+				break;
+			}
+			rc = libusb_set_interface_alt_setting(usb_devh, ifm->interface, ifm->altsetting);
+			if (rc < 0) {
+				fprintf(stderr, "Cannot set interface altsetting: %s\n", libusb_error_name(rc));
+				libusb_release_interface(usb_devh, ifm->interface);
+				libusb_close(usb_devh);
+				usb_devh = NULL;
+				break;
+			}
+		}
+	}
+
+	/* unref / free list */
+	for (dev = list; *dev; dev++)
+		libusb_unref_device(*dev);
+	talloc_free(list);
+
+	return usb_devh;
+}
+
+/*! obtain the endpoint addresses for a given USB interface.
+ *  \param[in] devh USB device handle on which to operate
+ *  \param[in] if_num USB Interface number on which to operate
+ *  \param[out] out user-provided storage for OUT endpoint number
+ *  \param[out] in user-provided storage for IN endpoint number
+ *  \param[out] irq user-provided storage for IRQ endpoint number
+ *  \returns 0 in case of success; negative in case of error */
+int osmo_libusb_get_ep_addrs(libusb_device_handle *devh, unsigned int if_num,
+			     uint8_t *out, uint8_t *in, uint8_t *irq)
+{
+	libusb_device *dev = libusb_get_device(devh);
+	struct libusb_config_descriptor *cdesc;
+	const struct libusb_interface_descriptor *idesc;
+	const struct libusb_interface *iface;
+	int rc, l;
+
+	rc = libusb_get_active_config_descriptor(dev, &cdesc);
+	if (rc < 0)
+		return rc;
+
+	iface = &cdesc->interface[if_num];
+	/* FIXME: we assume there's no altsetting */
+	idesc = &iface->altsetting[0];
+
+	for (l = 0; l < idesc->bNumEndpoints; l++) {
+		const struct libusb_endpoint_descriptor *edesc = &idesc->endpoint[l];
+		switch (edesc->bmAttributes & 3) {
+		case LIBUSB_TRANSFER_TYPE_BULK:
+			if (edesc->bEndpointAddress & 0x80) {
+				if (in)
+					*in = edesc->bEndpointAddress;
+			} else {
+				if (out)
+					*out = edesc->bEndpointAddress;
+			}
+			break;
+		case LIBUSB_TRANSFER_TYPE_INTERRUPT:
+			if (irq)
+				*irq = edesc->bEndpointAddress;
+			break;
+		default:
+			break;
+		}
+	}
+	return 0;
+}
 /***********************************************************************
  * initialization
  ***********************************************************************/