uwb: add WiMedia LLC Protocol stack (WSS)

Add the Wireless Service Set (WSS) code.
Signed-off-by: David Vrabel <david.vrabel@csr.com>

drivers/uwb/wlp/wss-lc.c

+/*
+ * WiMedia Logical Link Control Protocol (WLP)
+ *
+ * Copyright (C) 2007 Intel Corporation
+ * Reinette Chatre <reinette.chatre@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ *
+ * Implementation of the WLP association protocol.
+ *
+ * FIXME: Docs
+ *
+ * A UWB network interface will configure a WSS through wlp_wss_setup() after
+ * the interface has been assigned a MAC address, typically after
+ * "ifconfig" has been called. When the interface goes down it should call
+ * wlp_wss_remove().
+ *
+ * When the WSS is ready for use the user interacts via sysfs to create,
+ * discover, and activate WSS.
+ *
+ * wlp_wss_enroll_activate()
+ *
+ * wlp_wss_create_activate()
+ * 	wlp_wss_set_wssid_hash()
+ * 		wlp_wss_comp_wssid_hash()
+ * 	wlp_wss_sel_bcast_addr()
+ * 	wlp_wss_sysfs_add()
+ *
+ * Called when no more references to WSS exist:
+ * 	wlp_wss_release()
+ * 		wlp_wss_reset()
+ */
+
+#include <linux/etherdevice.h> /* for is_valid_ether_addr */
+#include <linux/skbuff.h>
+#include <linux/wlp.h>
+#define D_LOCAL 5
+#include <linux/uwb/debug.h>
+#include "wlp-internal.h"
+
+
+size_t wlp_wss_key_print(char *buf, size_t bufsize, u8 *key)
+{
+	size_t result;
+
+	result = scnprintf(buf, bufsize,
+			  "%02x %02x %02x %02x %02x %02x "
+			  "%02x %02x %02x %02x %02x %02x "
+			  "%02x %02x %02x %02x",
+			  key[0], key[1], key[2], key[3],
+			  key[4], key[5], key[6], key[7],
+			  key[8], key[9], key[10], key[11],
+			  key[12], key[13], key[14], key[15]);
+	return result;
+}
+
+/**
+ * Compute WSSID hash
+ * WLP Draft 0.99 [7.2.1]
+ *
+ * The WSSID hash for a WSSID is the result of an octet-wise exclusive-OR
+ * of all octets in the WSSID.
+ */
+static
+u8 wlp_wss_comp_wssid_hash(struct wlp_uuid *wssid)
+{
+	return wssid->data[0]  ^ wssid->data[1]  ^ wssid->data[2]
+	       ^ wssid->data[3]  ^ wssid->data[4]  ^ wssid->data[5]
+	       ^ wssid->data[6]  ^ wssid->data[7]  ^ wssid->data[8]
+	       ^ wssid->data[9]  ^ wssid->data[10] ^ wssid->data[11]
+	       ^ wssid->data[12] ^ wssid->data[13] ^ wssid->data[14]
+	       ^ wssid->data[15];
+}
+
+/**
+ * Select a multicast EUI-48 for the WSS broadcast address.
+ * WLP Draft 0.99 [7.2.1]
+ *
+ * Selected based on the WiMedia Alliance OUI, 00-13-88, within the WLP
+ * range, [01-13-88-00-01-00, 01-13-88-00-01-FF] inclusive.
+ *
+ * This address is currently hardcoded.
+ * FIXME?
+ */
+static
+struct uwb_mac_addr wlp_wss_sel_bcast_addr(struct wlp_wss *wss)
+{
+	struct uwb_mac_addr bcast = {
+		.data = { 0x01, 0x13, 0x88, 0x00, 0x01, 0x00 }
+	};
+	return bcast;
+}
+
+/**
+ * Clear the contents of the WSS structure - all except kobj, mutex, virtual
+ *
+ * We do not want to reinitialize - the internal kobj should not change as
+ * it still points to the parent received during setup. The mutex should
+ * remain also. We thus just reset values individually.
+ * The virutal address assigned to WSS will remain the same for the
+ * lifetime of the WSS. We only reset the fields that can change during its
+ * lifetime.
+ */
+void wlp_wss_reset(struct wlp_wss *wss)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	d_fnstart(5, dev, "wss (%p) \n", wss);
+	memset(&wss->wssid, 0, sizeof(wss->wssid));
+	wss->hash = 0;
+	memset(&wss->name[0], 0, sizeof(wss->name));
+	memset(&wss->bcast, 0, sizeof(wss->bcast));
+	wss->secure_status = WLP_WSS_UNSECURE;
+	memset(&wss->master_key[0], 0, sizeof(wss->master_key));
+	wss->tag = 0;
+	wss->state = WLP_WSS_STATE_NONE;
+	d_fnend(5, dev, "wss (%p) \n", wss);
+}
+
+/**
+ * Create sysfs infrastructure for WSS
+ *
+ * The WSS is configured to have the interface as parent (see wlp_wss_setup())
+ * a new sysfs directory that includes wssid as its name is created in the
+ * interface's sysfs directory. The group of files interacting with WSS are
+ * created also.
+ */
+static
+int wlp_wss_sysfs_add(struct wlp_wss *wss, char *wssid_str)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result;
+
+	d_fnstart(5, dev, "wss (%p), wssid: %s\n", wss, wssid_str);
+	result = kobject_set_name(&wss->kobj, "wss-%s", wssid_str);
+	if (result < 0)
+		return result;
+	wss->kobj.ktype = &wss_ktype;
+	result = kobject_init_and_add(&wss->kobj,
+			&wss_ktype, wss->kobj.parent, "wlp");
+	if (result < 0) {
+		dev_err(dev, "WLP: Cannot register WSS kobject.\n");
+		goto error_kobject_register;
+	}
+	result = sysfs_create_group(&wss->kobj, &wss_attr_group);
+	if (result < 0) {
+		dev_err(dev, "WLP: Cannot register WSS attributes: %d\n",
+			result);
+		goto error_sysfs_create_group;
+	}
+	d_fnend(5, dev, "Completed. result = %d \n", result);
+	return 0;
+error_sysfs_create_group:
+
+	kobject_put(&wss->kobj); /* will free name if needed */
+	return result;
+error_kobject_register:
+	kfree(wss->kobj.name);
+	wss->kobj.name = NULL;
+	wss->kobj.ktype = NULL;
+	return result;
+}
+
+
+/**
+ * Release WSS
+ *
+ * No more references exist to this WSS. We should undo everything that was
+ * done in wlp_wss_create_activate() except removing the group. The group
+ * is not removed because an object can be unregistered before the group is
+ * created. We also undo any additional operations on the WSS after this
+ * (addition of members).
+ *
+ * If memory was allocated for the kobject's name then it will
+ * be freed by the kobject system during this time.
+ *
+ * The EDA cache is removed and reinitilized when the WSS is removed. We
+ * thus loose knowledge of members of this WSS at that time and need not do
+ * it here.
+ */
+void wlp_wss_release(struct kobject *kobj)
+{
+	struct wlp_wss *wss = container_of(kobj, struct wlp_wss, kobj);
+
+	wlp_wss_reset(wss);
+}
+
+/**
+ * Enroll into a WSS using provided neighbor as registrar
+ *
+ * First search the neighborhood information to learn which neighbor is
+ * referred to, next proceed with enrollment.
+ *
+ * &wss->mutex is held
+ */
+static
+int wlp_wss_enroll_target(struct wlp_wss *wss, struct wlp_uuid *wssid,
+			  struct uwb_dev_addr *dest)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct wlp_neighbor_e *neighbor;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	int result = -ENXIO;
+	struct uwb_dev_addr *dev_addr;
+
+	wlp_wss_uuid_print(buf, sizeof(buf), wssid);
+	d_fnstart(5, dev, "wss %p, wssid %s, registrar %02x:%02x \n",
+		  wss, buf, dest->data[1], dest->data[0]);
+	mutex_lock(&wlp->nbmutex);
+	list_for_each_entry(neighbor, &wlp->neighbors, node) {
+		dev_addr = &neighbor->uwb_dev->dev_addr;
+		if (!memcmp(dest, dev_addr, sizeof(*dest))) {
+			d_printf(5, dev, "Neighbor %02x:%02x is valid, "
+				 "enrolling. \n",
+				 dev_addr->data[1], dev_addr->data[0]);
+			result = wlp_enroll_neighbor(wlp, neighbor, wss,
+						     wssid);
+			break;
+		}
+	}
+	if (result == -ENXIO)
+		dev_err(dev, "WLP: Cannot find neighbor %02x:%02x. \n",
+			dest->data[1], dest->data[0]);
+	mutex_unlock(&wlp->nbmutex);
+	d_fnend(5, dev, "wss %p, wssid %s, registrar %02x:%02x, result %d \n",
+		  wss, buf, dest->data[1], dest->data[0], result);
+	return result;
+}
+
+/**
+ * Enroll into a WSS previously discovered
+ *
+ * User provides WSSID of WSS, search for neighbor that has this WSS
+ * activated and attempt to enroll.
+ *
+ * &wss->mutex is held
+ */
+static
+int wlp_wss_enroll_discovered(struct wlp_wss *wss, struct wlp_uuid *wssid)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct wlp_neighbor_e *neighbor;
+	struct wlp_wssid_e *wssid_e;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	int result = -ENXIO;
+
+	wlp_wss_uuid_print(buf, sizeof(buf), wssid);
+	d_fnstart(5, dev, "wss %p, wssid %s \n", wss, buf);
+	mutex_lock(&wlp->nbmutex);
+	list_for_each_entry(neighbor, &wlp->neighbors, node) {
+		list_for_each_entry(wssid_e, &neighbor->wssid, node) {
+			if (!memcmp(wssid, &wssid_e->wssid, sizeof(*wssid))) {
+				d_printf(5, dev, "Found WSSID %s in neighbor "
+					 "%02x:%02x cache. \n", buf,
+					 neighbor->uwb_dev->dev_addr.data[1],
+					 neighbor->uwb_dev->dev_addr.data[0]);
+				result = wlp_enroll_neighbor(wlp, neighbor,
+							     wss, wssid);
+				if (result == 0) /* enrollment success */
+					goto out;
+				break;
+			}
+		}
+	}
+out:
+	if (result == -ENXIO)
+		dev_err(dev, "WLP: Cannot find WSSID %s in cache. \n", buf);
+	mutex_unlock(&wlp->nbmutex);
+	d_fnend(5, dev, "wss %p, wssid %s, result %d \n", wss, buf, result);
+	return result;
+}
+
+/**
+ * Enroll into WSS with provided WSSID, registrar may be provided
+ *
+ * @wss: out WSS that will be enrolled
+ * @wssid: wssid of neighboring WSS that we want to enroll in
+ * @devaddr: registrar can be specified, will be broadcast (ff:ff) if any
+ *           neighbor can be used as registrar.
+ *
+ * &wss->mutex is held
+ */
+static
+int wlp_wss_enroll(struct wlp_wss *wss, struct wlp_uuid *wssid,
+		   struct uwb_dev_addr *devaddr)
+{
+	int result;
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	struct uwb_dev_addr bcast = {.data = {0xff, 0xff} };
+
+	wlp_wss_uuid_print(buf, sizeof(buf), wssid);
+	if (wss->state != WLP_WSS_STATE_NONE) {
+		dev_err(dev, "WLP: Already enrolled in WSS %s.\n", buf);
+		result = -EEXIST;
+		goto error;
+	}
+	if (!memcmp(&bcast, devaddr, sizeof(bcast))) {
+		d_printf(5, dev, "Request to enroll in discovered WSS "
+			 "with WSSID %s \n", buf);
+		result = wlp_wss_enroll_discovered(wss, wssid);
+	} else {
+		d_printf(5, dev, "Request to enroll in WSSID %s with "
+			 "registrar %02x:%02x\n", buf, devaddr->data[1],
+			 devaddr->data[0]);
+		result = wlp_wss_enroll_target(wss, wssid, devaddr);
+	}
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to enroll into WSS %s, result %d \n",
+			buf, result);
+		goto error;
+	}
+	d_printf(2, dev, "Successfully enrolled into WSS %s \n", buf);
+	result = wlp_wss_sysfs_add(wss, buf);
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to set up sysfs for WSS kobject.\n");
+		wlp_wss_reset(wss);
+	}
+error:
+	return result;
+
+}
+
+/**
+ * Activate given WSS
+ *
+ * Prior to activation a WSS must be enrolled. To activate a WSS a device
+ * includes the WSS hash in the WLP IE in its beacon in each superframe.
+ * WLP 0.99 [7.2.5].
+ *
+ * The WSS tag is also computed at this time. We only support one activated
+ * WSS so we can use the hash as a tag - there will never be a conflict.
+ *
+ * We currently only support one activated WSS so only one WSS hash is
+ * included in the WLP IE.
+ */
+static
+int wlp_wss_activate(struct wlp_wss *wss)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct uwb_rc *uwb_rc = wlp->rc;
+	int result;
+	struct {
+		struct wlp_ie wlp_ie;
+		u8 hash; /* only include one hash */
+	} ie_data;
+
+	d_fnstart(5, dev, "Activating WSS %p. \n", wss);
+	BUG_ON(wss->state != WLP_WSS_STATE_ENROLLED);
+	wss->hash = wlp_wss_comp_wssid_hash(&wss->wssid);
+	wss->tag = wss->hash;
+	memset(&ie_data, 0, sizeof(ie_data));
+	ie_data.wlp_ie.hdr.element_id = UWB_IE_WLP;
+	ie_data.wlp_ie.hdr.length = sizeof(ie_data) - sizeof(struct uwb_ie_hdr);
+	wlp_ie_set_hash_length(&ie_data.wlp_ie, sizeof(ie_data.hash));
+	ie_data.hash = wss->hash;
+	result = uwb_rc_ie_add(uwb_rc, &ie_data.wlp_ie.hdr,
+			       sizeof(ie_data));
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to add WLP IE to beacon. "
+			"result = %d.\n", result);
+		goto error_wlp_ie;
+	}
+	wss->state = WLP_WSS_STATE_ACTIVE;
+	result = 0;
+error_wlp_ie:
+	d_fnend(5, dev, "Activating WSS %p, result = %d \n", wss, result);
+	return result;
+}
+
+/**
+ * Enroll in and activate WSS identified by provided WSSID
+ *
+ * The neighborhood cache should contain a list of all neighbors and the
+ * WSS they have activated. Based on that cache we search which neighbor we
+ * can perform the association process with. The user also has option to
+ * specify which neighbor it prefers as registrar.
+ * Successful enrollment is followed by activation.
+ * Successful activation will create the sysfs directory containing
+ * specific information regarding this WSS.
+ */
+int wlp_wss_enroll_activate(struct wlp_wss *wss, struct wlp_uuid *wssid,
+			    struct uwb_dev_addr *devaddr)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = 0;
+	char buf[WLP_WSS_UUID_STRSIZE];
+
+	d_fnstart(5, dev, "Enrollment and activation requested. \n");
+	mutex_lock(&wss->mutex);
+	result = wlp_wss_enroll(wss, wssid, devaddr);
+	if (result < 0) {
+		wlp_wss_uuid_print(buf, sizeof(buf), &wss->wssid);
+		dev_err(dev, "WLP: Enrollment into WSS %s failed.\n", buf);
+		goto error_enroll;
+	}
+	result = wlp_wss_activate(wss);
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to activate WSS. Undoing enrollment "
+			"result = %d \n", result);
+		/* Undo enrollment */
+		wlp_wss_reset(wss);
+		goto error_activate;
+	}
+error_activate:
+error_enroll:
+	mutex_unlock(&wss->mutex);
+	d_fnend(5, dev, "Completed. result = %d \n", result);
+	return result;
+}
+
+/**
+ * Create, enroll, and activate a new WSS
+ *
+ * @wssid: new wssid provided by user
+ * @name:  WSS name requested by used.
+ * @sec_status: security status requested by user
+ *
+ * A user requested the creation of a new WSS. All operations are done
+ * locally. The new WSS will be stored locally, the hash will be included
+ * in the WLP IE, and the sysfs infrastructure for this WSS will be
+ * created.
+ */
+int wlp_wss_create_activate(struct wlp_wss *wss, struct wlp_uuid *wssid,
+			    char *name, unsigned sec_status, unsigned accept)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = 0;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	d_fnstart(5, dev, "Request to create new WSS.\n");
+	result = wlp_wss_uuid_print(buf, sizeof(buf), wssid);
+	d_printf(5, dev, "Request to create WSS: WSSID=%s, name=%s, "
+		 "sec_status=%u, accepting enrollment=%u \n",
+		 buf, name, sec_status, accept);
+	if (!mutex_trylock(&wss->mutex)) {
+		dev_err(dev, "WLP: WLP association session in progress.\n");
+		return -EBUSY;
+	}
+	if (wss->state != WLP_WSS_STATE_NONE) {
+		dev_err(dev, "WLP: WSS already exists. Not creating new.\n");
+		result = -EEXIST;
+		goto out;
+	}
+	if (wss->kobj.parent == NULL) {
+		dev_err(dev, "WLP: WSS parent not ready. Is network interface "
+		       "up?\n");
+		result = -ENXIO;
+		goto out;
+	}
+	if (sec_status == WLP_WSS_SECURE) {
+		dev_err(dev, "WLP: FIXME Creation of secure WSS not "
+			"supported yet.\n");
+		result = -EINVAL;
+		goto out;
+	}
+	wss->wssid = *wssid;
+	memcpy(wss->name, name, sizeof(wss->name));
+	wss->bcast = wlp_wss_sel_bcast_addr(wss);
+	wss->secure_status = sec_status;
+	wss->accept_enroll = accept;
+	/*wss->virtual_addr is initialized in call to wlp_wss_setup*/
+	/* sysfs infrastructure */
+	result = wlp_wss_sysfs_add(wss, buf);
+	if (result < 0) {
+		dev_err(dev, "Cannot set up sysfs for WSS kobject.\n");
+		wlp_wss_reset(wss);
+		goto out;
+	} else
+		result = 0;
+	wss->state = WLP_WSS_STATE_ENROLLED;
+	result = wlp_wss_activate(wss);
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to activate WSS. Undoing "
+			"enrollment\n");
+		wlp_wss_reset(wss);
+		goto out;
+	}
+	result = 0;
+out:
+	mutex_unlock(&wss->mutex);
+	d_fnend(5, dev, "Completed. result = %d \n", result);
+	return result;
+}
+
+/**
+ * Determine if neighbor has WSS activated
+ *
+ * @returns: 1 if neighbor has WSS activated, zero otherwise
+ *
+ * This can be done in two ways:
+ * - send a C1 frame, parse C2/F0 response
+ * - examine the WLP IE sent by the neighbor
+ *
+ * The WLP IE is not fully supported in hardware so we use the C1/C2 frame
+ * exchange to determine if a WSS is activated. Using the WLP IE should be
+ * faster and should be used when it becomes possible.
+ */
+int wlp_wss_is_active(struct wlp *wlp, struct wlp_wss *wss,
+		      struct uwb_dev_addr *dev_addr)
+{
+	int result = 0;
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	DECLARE_COMPLETION_ONSTACK(completion);
+	struct wlp_session session;
+	struct sk_buff  *skb;
+	struct wlp_frame_assoc *resp;
+	struct wlp_uuid wssid;
+
+	wlp_wss_uuid_print(buf, sizeof(buf), &wss->wssid);
+	d_fnstart(5, dev, "wlp %p, wss %p (wssid %s), neighbor %02x:%02x \n",
+		  wlp, wss, buf, dev_addr->data[1], dev_addr->data[0]);
+	mutex_lock(&wlp->mutex);
+	/* Send C1 association frame */
+	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_C1);
+	if (result < 0) {
+		dev_err(dev, "Unable to send C1 frame to neighbor "
+			"%02x:%02x (%d)\n", dev_addr->data[1],
+			dev_addr->data[0], result);
+		result = 0;
+		goto out;
+	}
+	/* Create session, wait for response */
+	session.exp_message = WLP_ASSOC_C2;
+	session.cb = wlp_session_cb;
+	session.cb_priv = &completion;
+	session.neighbor_addr = *dev_addr;
+	BUG_ON(wlp->session != NULL);
+	wlp->session = &session;
+	/* Wait for C2/F0 frame */
+	result = wait_for_completion_interruptible_timeout(&completion,
+						   WLP_PER_MSG_TIMEOUT * HZ);
+	if (result == 0) {
+		dev_err(dev, "Timeout while sending C1 to neighbor "
+			     "%02x:%02x.\n", dev_addr->data[1],
+			     dev_addr->data[0]);
+		goto out;
+	}
+	if (result < 0) {
+		dev_err(dev, "Unable to send C1 to neighbor %02x:%02x.\n",
+			dev_addr->data[1], dev_addr->data[0]);
+		result = 0;
+		goto out;
+	}
+	/* Parse message in session->data: it will be either C2 or F0 */
+	skb = session.data;
+	resp = (void *) skb->data;
+	d_printf(5, dev, "Received response to C1 frame. \n");
+	d_dump(5, dev, skb->data, skb->len > 72 ? 72 : skb->len);
+	if (resp->type == WLP_ASSOC_F0) {
+		result = wlp_parse_f0(wlp, skb);
+		if (result < 0)
+			dev_err(dev, "WLP:  unable to parse incoming F0 "
+				"frame from neighbor %02x:%02x.\n",
+				dev_addr->data[1], dev_addr->data[0]);
+		result = 0;
+		goto error_resp_parse;
+	}
+	/* WLP version and message type fields have already been parsed */
+	result = wlp_get_wssid(wlp, (void *)resp + sizeof(*resp), &wssid,
+			       skb->len - sizeof(*resp));
+	if (result < 0) {
+		dev_err(dev, "WLP: unable to obtain WSSID from C2 frame.\n");
+		result = 0;
+		goto error_resp_parse;
+	}
+	if (!memcmp(&wssid, &wss->wssid, sizeof(wssid))) {
+		d_printf(5, dev, "WSSID in C2 frame matches local "
+			 "active WSS.\n");
+		result = 1;
+	} else {
+		dev_err(dev, "WLP: Received a C2 frame without matching "
+			"WSSID.\n");
+		result = 0;
+	}
+error_resp_parse:
+	kfree_skb(skb);
+out:
+	wlp->session = NULL;
+	mutex_unlock(&wlp->mutex);
+	d_fnend(5, dev, "wlp %p, wss %p (wssid %s), neighbor %02x:%02x \n",
+		  wlp, wss, buf, dev_addr->data[1], dev_addr->data[0]);
+	return result;
+}
+
+/**
+ * Activate connection with neighbor by updating EDA cache
+ *
+ * @wss:       local WSS to which neighbor wants to connect
+ * @dev_addr:  neighbor's address
+ * @wssid:     neighbor's WSSID - must be same as our WSS's WSSID
+ * @tag:       neighbor's WSS tag used to identify frames transmitted by it
+ * @virt_addr: neighbor's virtual EUI-48
+ */
+static
+int wlp_wss_activate_connection(struct wlp *wlp, struct wlp_wss *wss,
+				struct uwb_dev_addr *dev_addr,
+				struct wlp_uuid *wssid, u8 *tag,
+				struct uwb_mac_addr *virt_addr)
+{
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = 0;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	wlp_wss_uuid_print(buf, sizeof(buf), wssid);
+	d_fnstart(5, dev, "wlp %p, wss %p, wssid %s, tag %u, virtual "
+		  "%02x:%02x:%02x:%02x:%02x:%02x \n", wlp, wss, buf, *tag,
+		  virt_addr->data[0], virt_addr->data[1], virt_addr->data[2],
+		  virt_addr->data[3], virt_addr->data[4], virt_addr->data[5]);
+
+	if (!memcmp(wssid, &wss->wssid, sizeof(*wssid))) {
+		d_printf(5, dev, "WSSID from neighbor frame matches local "
+			 "active WSS.\n");
+		/* Update EDA cache */
+		result = wlp_eda_update_node(&wlp->eda, dev_addr, wss,
+					     (void *) virt_addr->data, *tag,
+					     WLP_WSS_CONNECTED);
+		if (result < 0)
+			dev_err(dev, "WLP: Unable to update EDA cache "
+				"with new connected neighbor information.\n");
+	} else {
+		dev_err(dev, "WLP: Neighbor does not have matching "
+			"WSSID.\n");
+		result = -EINVAL;
+	}
+
+	d_fnend(5, dev, "wlp %p, wss %p, wssid %s, tag %u, virtual "
+		  "%02x:%02x:%02x:%02x:%02x:%02x, result = %d \n",
+		  wlp, wss, buf, *tag,
+		  virt_addr->data[0], virt_addr->data[1], virt_addr->data[2],
+		  virt_addr->data[3], virt_addr->data[4], virt_addr->data[5],
+		  result);
+
+	return result;
+}
+
+/**
+ * Connect to WSS neighbor
+ *
+ * Use C3/C4 exchange to determine if neighbor has WSS activated and
+ * retrieve the WSS tag and virtual EUI-48 of the neighbor.
+ */
+static
+int wlp_wss_connect_neighbor(struct wlp *wlp, struct wlp_wss *wss,
+			     struct uwb_dev_addr *dev_addr)
+{
+	int result;
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	char buf[WLP_WSS_UUID_STRSIZE];
+	struct wlp_uuid wssid;
+	u8 tag;
+	struct uwb_mac_addr virt_addr;
+	DECLARE_COMPLETION_ONSTACK(completion);
+	struct wlp_session session;
+	struct wlp_frame_assoc *resp;
+	struct sk_buff *skb;
+
+	wlp_wss_uuid_print(buf, sizeof(buf), &wss->wssid);
+	d_fnstart(5, dev, "wlp %p, wss %p (wssid %s), neighbor %02x:%02x \n",
+		  wlp, wss, buf, dev_addr->data[1], dev_addr->data[0]);
+	mutex_lock(&wlp->mutex);
+	/* Send C3 association frame */
+	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_C3);
+	if (result < 0) {
+		dev_err(dev, "Unable to send C3 frame to neighbor "
+			"%02x:%02x (%d)\n", dev_addr->data[1],
+			dev_addr->data[0], result);
+		goto out;
+	}
+	/* Create session, wait for response */
+	session.exp_message = WLP_ASSOC_C4;
+	session.cb = wlp_session_cb;
+	session.cb_priv = &completion;
+	session.neighbor_addr = *dev_addr;
+	BUG_ON(wlp->session != NULL);
+	wlp->session = &session;
+	/* Wait for C4/F0 frame */
+	result = wait_for_completion_interruptible_timeout(&completion,
+						   WLP_PER_MSG_TIMEOUT * HZ);
+	if (result == 0) {
+		dev_err(dev, "Timeout while sending C3 to neighbor "
+			     "%02x:%02x.\n", dev_addr->data[1],
+			     dev_addr->data[0]);
+		result = -ETIMEDOUT;
+		goto out;
+	}
+	if (result < 0) {
+		dev_err(dev, "Unable to send C3 to neighbor %02x:%02x.\n",
+			dev_addr->data[1], dev_addr->data[0]);
+		goto out;
+	}
+	/* Parse message in session->data: it will be either C4 or F0 */
+	skb = session.data;
+	resp = (void *) skb->data;
+	d_printf(5, dev, "Received response to C3 frame. \n");
+	d_dump(5, dev, skb->data, skb->len > 72 ? 72 : skb->len);
+	if (resp->type == WLP_ASSOC_F0) {
+		result = wlp_parse_f0(wlp, skb);
+		if (result < 0)
+			dev_err(dev, "WLP: unable to parse incoming F0 "
+				"frame from neighbor %02x:%02x.\n",
+				dev_addr->data[1], dev_addr->data[0]);
+		result = -EINVAL;
+		goto error_resp_parse;
+	}
+	result = wlp_parse_c3c4_frame(wlp, skb, &wssid, &tag, &virt_addr);
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to parse C4 frame from neighbor.\n");
+		goto error_resp_parse;
+	}
+	result = wlp_wss_activate_connection(wlp, wss, dev_addr, &wssid, &tag,
+					     &virt_addr);
+	if (result < 0) {
+		dev_err(dev, "WLP: Unable to activate connection to "
+			"neighbor %02x:%02x.\n", dev_addr->data[1],
+			dev_addr->data[0]);
+		goto error_resp_parse;
+	}
+error_resp_parse:
+	kfree_skb(skb);
+out:
+	/* Record that we unsuccessfully tried to connect to this neighbor */
+	if (result < 0)
+		wlp_eda_update_node_state(&wlp->eda, dev_addr,
+					  WLP_WSS_CONNECT_FAILED);
+	wlp->session = NULL;
+	mutex_unlock(&wlp->mutex);
+	d_fnend(5, dev, "wlp %p, wss %p (wssid %s), neighbor %02x:%02x \n",
+		  wlp, wss, buf, dev_addr->data[1], dev_addr->data[0]);
+	return result;
+}
+
+/**
+ * Connect to neighbor with common WSS, send pending frame
+ *
+ * This function is scheduled when a frame is destined to a neighbor with
+ * which we do not have a connection. A copy of the EDA cache entry is
+ * provided - not the actual cache entry (because it is protected by a
+ * spinlock).
+ *
+ * First determine if neighbor has the same WSS activated, connect if it
+ * does. The C3/C4 exchange is dual purpose to determine if neighbor has
+ * WSS activated and proceed with the connection.
+ *
+ * The frame that triggered the connection setup is sent after connection
+ * setup.
+ *
+ * network queue is stopped - we need to restart when done
+ *
+ */
+static
+void wlp_wss_connect_send(struct work_struct *ws)
+{
+	struct wlp_assoc_conn_ctx *conn_ctx = container_of(ws,
+						  struct wlp_assoc_conn_ctx,
+						  ws);
+	struct wlp *wlp = conn_ctx->wlp;
+	struct sk_buff *skb = conn_ctx->skb;
+	struct wlp_eda_node *eda_entry = &conn_ctx->eda_entry;
+	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
+	struct wlp_wss *wss = &wlp->wss;
+	int result;
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	char buf[WLP_WSS_UUID_STRSIZE];
+
+	mutex_lock(&wss->mutex);
+	wlp_wss_uuid_print(buf, sizeof(buf), &wss->wssid);
+	d_fnstart(5, dev, "wlp %p, wss %p (wssid %s), neighbor %02x:%02x \n",
+		  wlp, wss, buf, dev_addr->data[1], dev_addr->data[0]);
+	if (wss->state < WLP_WSS_STATE_ACTIVE) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Attempting to connect with "
+				"WSS that is not active or connected.\n");
+		dev_kfree_skb(skb);
+		goto out;
+	}
+	/* Establish connection - send C3 rcv C4 */
+	result = wlp_wss_connect_neighbor(wlp, wss, dev_addr);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to establish connection "
+				"with neighbor %02x:%02x.\n",
+				dev_addr->data[1], dev_addr->data[0]);
+		dev_kfree_skb(skb);
+		goto out;
+	}
+	/* EDA entry changed, update the local copy being used */
+	result = wlp_copy_eda_node(&wlp->eda, dev_addr, eda_entry);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Cannot find EDA entry for "
+				"neighbor %02x:%02x \n",
+				dev_addr->data[1], dev_addr->data[0]);
+	}
+	result = wlp_wss_prep_hdr(wlp, eda_entry, skb);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to prepare frame header for "
+				"transmission (neighbor %02x:%02x). \n",
+				dev_addr->data[1], dev_addr->data[0]);
+		dev_kfree_skb(skb);
+		goto out;
+	}
+	BUG_ON(wlp->xmit_frame == NULL);
+	result = wlp->xmit_frame(wlp, skb, dev_addr);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to transmit frame: %d\n",
+				result);
+		if (result == -ENXIO)
+			dev_err(dev, "WLP: Is network interface up? \n");
+		/* We could try again ... */
+		dev_kfree_skb(skb);/*we need to free if tx fails */
+	}
+out:
+	kfree(conn_ctx);
+	BUG_ON(wlp->start_queue == NULL);
+	wlp->start_queue(wlp);
+	mutex_unlock(&wss->mutex);
+	d_fnend(5, dev, "wlp %p, wss %p (wssid %s)\n", wlp, wss, buf);
+}
+
+/**
+ * Add WLP header to outgoing skb
+ *
+ * @eda_entry: pointer to neighbor's entry in the EDA cache
+ * @_skb:      skb containing data destined to the neighbor
+ */
+int wlp_wss_prep_hdr(struct wlp *wlp, struct wlp_eda_node *eda_entry,
+		     void *_skb)
+{
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = 0;
+	unsigned char *eth_addr = eda_entry->eth_addr;
+	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
+	struct sk_buff *skb = _skb;
+	struct wlp_frame_std_abbrv_hdr *std_hdr;
+
+	d_fnstart(6, dev, "wlp %p \n", wlp);
+	if (eda_entry->state == WLP_WSS_CONNECTED) {
+		/* Add WLP header */
+		BUG_ON(skb_headroom(skb) < sizeof(*std_hdr));
+		std_hdr = (void *) __skb_push(skb, sizeof(*std_hdr));
+		std_hdr->hdr.mux_hdr = cpu_to_le16(WLP_PROTOCOL_ID);
+		std_hdr->hdr.type = WLP_FRAME_STANDARD;
+		std_hdr->tag = eda_entry->wss->tag;
+	} else {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Destination neighbor (Ethernet: "
+				"%02x:%02x:%02x:%02x:%02x:%02x, Dev: "
+				"%02x:%02x) is not connected. \n", eth_addr[0],
+				eth_addr[1], eth_addr[2], eth_addr[3],
+				eth_addr[4], eth_addr[5], dev_addr->data[1],
+				dev_addr->data[0]);
+		result = -EINVAL;
+	}
+	d_fnend(6, dev, "wlp %p \n", wlp);
+	return result;
+}
+
+
+/**
+ * Prepare skb for neighbor: connect if not already and prep WLP header
+ *
+ * This function is called in interrupt context, but it needs to sleep. We
+ * temporarily stop the net queue to establish the WLP connection.
+ * Setup of the WLP connection and restart of queue is scheduled
+ * on the default work queue.
+ *
+ * run with eda->lock held (spinlock)
+ */
+int wlp_wss_connect_prep(struct wlp *wlp, struct wlp_eda_node *eda_entry,
+			 void *_skb)
+{
+	int result = 0;
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
+	unsigned char *eth_addr = eda_entry->eth_addr;
+	struct sk_buff *skb = _skb;
+	struct wlp_assoc_conn_ctx *conn_ctx;
+
+	d_fnstart(5, dev, "wlp %p\n", wlp);
+	d_printf(5, dev, "To neighbor %02x:%02x with eth "
+		  "%02x:%02x:%02x:%02x:%02x:%02x\n", dev_addr->data[1],
+		  dev_addr->data[0], eth_addr[0], eth_addr[1], eth_addr[2],
+		  eth_addr[3], eth_addr[4], eth_addr[5]);
+	if (eda_entry->state == WLP_WSS_UNCONNECTED) {
+		/* We don't want any more packets while we set up connection */
+		BUG_ON(wlp->stop_queue == NULL);
+		wlp->stop_queue(wlp);
+		conn_ctx = kmalloc(sizeof(*conn_ctx), GFP_ATOMIC);
+		if (conn_ctx == NULL) {
+			if (printk_ratelimit())
+				dev_err(dev, "WLP: Unable to allocate memory "
+					"for connection handling.\n");
+			result = -ENOMEM;
+			goto out;
+		}
+		conn_ctx->wlp = wlp;
+		conn_ctx->skb = skb;
+		conn_ctx->eda_entry = *eda_entry;
+		INIT_WORK(&conn_ctx->ws, wlp_wss_connect_send);
+		schedule_work(&conn_ctx->ws);
+		result = 1;
+	} else if (eda_entry->state == WLP_WSS_CONNECT_FAILED) {
+		/* Previous connection attempts failed, don't retry - see
+		 * conditions for connection in WLP 0.99 [7.6.2] */
+		if (printk_ratelimit())
+			dev_err(dev, "Could not connect to neighbor "
+			 "previously. Not retrying. \n");
+		result = -ENONET;
+		goto out;
+	} else { /* eda_entry->state == WLP_WSS_CONNECTED */
+		d_printf(5, dev, "Neighbor is connected, preparing frame.\n");
+		result = wlp_wss_prep_hdr(wlp, eda_entry, skb);
+	}
+out:
+	d_fnend(5, dev, "wlp %p, result = %d \n", wlp, result);
+	return result;
+}
+
+/**
+ * Emulate broadcast: copy skb, send copy to neighbor (connect if not already)
+ *
+ * We need to copy skbs in the case where we emulate broadcast through
+ * unicast. We copy instead of clone because we are modifying the data of
+ * the frame after copying ... clones share data so we cannot emulate
+ * broadcast using clones.
+ *
+ * run with eda->lock held (spinlock)
+ */
+int wlp_wss_send_copy(struct wlp *wlp, struct wlp_eda_node *eda_entry,
+		      void *_skb)
+{
+	int result = -ENOMEM;
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	struct sk_buff *skb = _skb;
+	struct sk_buff *copy;
+	struct uwb_dev_addr *dev_addr = &eda_entry->dev_addr;
+
+	d_fnstart(5, dev, "to neighbor %02x:%02x, skb (%p) \n",
+		  dev_addr->data[1], dev_addr->data[0], skb);
+	copy = skb_copy(skb, GFP_ATOMIC);
+	if (copy == NULL) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to copy skb for "
+				"transmission.\n");
+		goto out;
+	}
+	result = wlp_wss_connect_prep(wlp, eda_entry, copy);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to connect/send skb "
+				"to neighbor.\n");
+		dev_kfree_skb_irq(copy);
+		goto out;
+	} else if (result == 1)
+		/* Frame will be transmitted separately */
+		goto out;
+	BUG_ON(wlp->xmit_frame == NULL);
+	result = wlp->xmit_frame(wlp, copy, dev_addr);
+	if (result < 0) {
+		if (printk_ratelimit())
+			dev_err(dev, "WLP: Unable to transmit frame: %d\n",
+				result);
+		if ((result == -ENXIO) && printk_ratelimit())
+			dev_err(dev, "WLP: Is network interface up? \n");
+		/* We could try again ... */
+		dev_kfree_skb_irq(copy);/*we need to free if tx fails */
+	}
+out:
+	d_fnend(5, dev, "to neighbor %02x:%02x \n", dev_addr->data[1],
+		  dev_addr->data[0]);
+	return result;
+}
+
+
+/**
+ * Setup WSS
+ *
+ * Should be called by network driver after the interface has been given a
+ * MAC address.
+ */
+int wlp_wss_setup(struct net_device *net_dev, struct wlp_wss *wss)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	int result = 0;
+	d_fnstart(5, dev, "wss (%p) \n", wss);
+	mutex_lock(&wss->mutex);
+	wss->kobj.parent = &net_dev->dev.kobj;
+	if (!is_valid_ether_addr(net_dev->dev_addr)) {
+		dev_err(dev, "WLP: Invalid MAC address. Cannot use for"
+		       "virtual.\n");
+		result = -EINVAL;
+		goto out;
+	}
+	memcpy(wss->virtual_addr.data, net_dev->dev_addr,
+	       sizeof(wss->virtual_addr.data));
+out:
+	mutex_unlock(&wss->mutex);
+	d_fnend(5, dev, "wss (%p) \n", wss);
+	return result;
+}
+EXPORT_SYMBOL_GPL(wlp_wss_setup);
+
+/**
+ * Remove WSS
+ *
+ * Called by client that configured WSS through wlp_wss_setup(). This
+ * function is called when client no longer needs WSS, eg. client shuts
+ * down.
+ *
+ * We remove the WLP IE from the beacon before initiating local cleanup.
+ */
+void wlp_wss_remove(struct wlp_wss *wss)
+{
+	struct wlp *wlp = container_of(wss, struct wlp, wss);
+	struct device *dev = &wlp->rc->uwb_dev.dev;
+	d_fnstart(5, dev, "wss (%p) \n", wss);
+	mutex_lock(&wss->mutex);
+	if (wss->state == WLP_WSS_STATE_ACTIVE)
+		uwb_rc_ie_rm(wlp->rc, UWB_IE_WLP);
+	if (wss->state != WLP_WSS_STATE_NONE) {
+		sysfs_remove_group(&wss->kobj, &wss_attr_group);
+		kobject_put(&wss->kobj);
+	}
+	wss->kobj.parent = NULL;
+	memset(&wss->virtual_addr, 0, sizeof(wss->virtual_addr));
+	/* Cleanup EDA cache */
+	wlp_eda_release(&wlp->eda);
+	wlp_eda_init(&wlp->eda);
+	mutex_unlock(&wss->mutex);
+	d_fnend(5, dev, "wss (%p) \n", wss);
+}
+EXPORT_SYMBOL_GPL(wlp_wss_remove);