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+/* This source file is part of the ATMEL AVR-UC3-SoftwareFramework-1.7.0 Release */
+
+/*! \page License
+ * Copyright (C) 2009, H&D Wireless AB All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * 3. The name of H&D Wireless AB may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY H&D WIRELESS AB ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND
+ * SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include "wl_cm.h"
+#include "util.h"
+#include <string.h>
+#include "debug.h"
+
+/** Roaming configuration parameters **/
+
+/*! The ROAMING_RSSI_THRESHOLD setting defines how bad the current
+ * signal strength should be before we'll consider roaming to an AP
+ * with better signal strength. The objective is to stay on the
+ * current AP as long as the RSSI is decent, even if there are other
+ * APs in the same BSS with better RSSI available.
+ * If ROAMING_RSSI_THRESHOLD is too high we might roam unecessarily.
+ * If ROAMING_RSSI_THRESHOLD is too low we might not roam in time to
+ * avoid packet loss. This also impacts power consumption, staying
+ * too long with an AP with poor RSSI will consume more power.
+ * Unit is dBm.
+ */
+#define ROAMING_RSSI_THRESHOLD -65
+
+/*! The ROAMING_RSSI_DIFF setting defines how much better
+ * than the currently associated AP a new AP must be before
+ * we'll attempt to roam over to the new AP.
+ * If ROAMING_RSSI_DIFF is too high it might be too hard
+ * to roam (important if the STA is expected to move
+ * quickly through different AP coverage areas).
+ * If ROAMING_RSSI_DIFF is too low we might bounce between
+ * two APs with similar signal strengths.
+ * Unit is dBm.
+ */
+#define ROAMING_RSSI_DIFF 10
+
+
+#if 1
+# include "printf-stdarg.h"
+#include "ard_utils.h"
+# define CM_DPRINTF(fmt...) if (enableDebug & INFO_CM_FLAG) printk(fmt)
+#else
+# define CM_DPRINTF(fmt...)
+#endif
+
+
+/** \defgroup wl_cm Connection Manager
+ *
+ * These functions are used to configure and control the WiFi connetion
+ * manager.
+ *
+ *
+ * @{
+ */
+
+struct cm_candidate {
+ struct wl_ssid_t ssid;
+ struct wl_mac_addr_t bssid;
+};
+
+struct cm {
+ cm_scan_cb_t *scan_cb;
+ cm_conn_cb_t *conn_cb;
+ cm_disconn_cb_t *disconn_cb;
+ void* ctx;
+ uint8_t enabled;
+ struct cm_candidate candidate;
+};
+
+
+/**
+ * This function can be modified to pick a network based on
+ * application specific criteria.
+ *
+ * If the SSID can not be found in the scan list it will be
+ * assumed to be a hidden SSID and the wl_connect() command
+ * will be called to attempt to probe for the network and
+ * connect to it.
+ */
+static struct wl_network_t*
+find_best_candidate(struct cm* cm)
+{
+ struct wl_network_list_t* netlist;
+ struct wl_network_t *best_net = NULL;
+ uint8_t i;
+
+ if (wl_get_network_list(&netlist) != WL_SUCCESS)
+ return NULL;
+
+ if (netlist->cnt == 0)
+ return NULL;
+
+ for (i = 0; i < netlist->cnt; i++) {
+ /* match on ssid */
+ if (cm->candidate.ssid.len)
+ if (!equal_ssid(&cm->candidate.ssid,
+ &netlist->net[i]->ssid))
+ continue;
+
+ /* match bssid */
+ if (strncmp((char*) cm->candidate.bssid.octet,
+ "\xff\xff\xff\xff\xff\xff", 6))
+ if (!equal_bssid(&cm->candidate.bssid,
+ &netlist->net[i]->bssid))
+ continue;
+ /* check for best rssi. */
+ if ( best_net &&
+ ( best_net->rssi > netlist->net[i]->rssi) ) {
+ continue;
+ }
+ best_net = netlist->net[i];
+ }
+
+ return best_net;
+}
+
+
+/**
+ *
+ */
+static void
+select_net(struct cm* cm)
+{
+ struct wl_network_t *candidate_net;
+ struct wl_network_t *current_net;
+ struct wl_ssid_t *ssid_p;
+
+ int ret;
+
+ /* Nothing to do */
+ if (0 == cm->candidate.ssid.len) {
+ return;
+ }
+
+ current_net = wl_get_current_network();
+ candidate_net = find_best_candidate(cm);
+
+ /* Connected to the candidate? ... */
+ if ( current_net == candidate_net ) {
+ if ( current_net ) {
+ /* ...yes, dont change. */
+
+ return;
+ }
+ }
+
+ /* Roaming checks */
+ if (current_net && candidate_net) {
+ /* Are we changing BSSs? */
+ if ( equal_ssid(&candidate_net->ssid,
+ &current_net->ssid)) {
+
+ /* ...no. Does the currently connected
+ * net have a decent RSSI?...*/
+ if ( current_net->rssi > ROAMING_RSSI_THRESHOLD ) {
+ /* ...yes, stay with it. */
+ return;
+ }
+ /* ...no. Does the candidate have
+ * sufficiently better RSSI to
+ * motivate a switch to it? */
+ if ( candidate_net->rssi < current_net->rssi +
+ ROAMING_RSSI_DIFF) {
+ return;
+ }
+ /* ...yes, try to roam to candidate_net */
+ CM_DPRINTF("CM: Roaming from rssi %d to %d\n",
+ current_net->rssi,
+ candidate_net->rssi);
+ }
+ }
+ /* a candidate is found */
+ if (candidate_net) {
+ /* We connect to a specific bssid here because
+ * find_best_candidate() might have picked a
+ * particulare AP among many with the same SSID.
+ * wl_connect() would pick one of them at random.
+ */
+ ret = wl_connect_bssid(candidate_net->bssid);
+ }
+ /* no candidate found */
+ else {
+ CM_DPRINTF("CM: No candidate found for ssid \"%s\"\n",
+ ssid2str(&cm->candidate.ssid));
+ /* Might be a hidden SSID so we try to connect to it.
+ * wl_connect() will trigger a directed scan
+ * for the SSID in this case.
+ */
+ ssid_p = &cm->candidate.ssid;
+ ret = wl_connect(ssid_p->ssid, ssid_p->len);
+ }
+ switch (ret) {
+ case WL_SUCCESS :
+ return;
+ case WL_BUSY:
+ wl_disconnect();
+ return;
+ case WL_RETRY:
+ break;
+ default :
+ CM_DPRINTF("CM: failed to connect\n");
+ break;
+ }
+
+ /* some operation failed or no candidate found */
+ if (wl_scan() != WL_SUCCESS)
+ CM_DPRINTF("CM: failed to scan\n");
+}
+
+
+/**
+ *
+ */
+static void
+wl_scan_complete_cb(void* ctx)
+{
+ struct cm *cm = ctx;
+
+ CM_DPRINTF("CM: scan completed\n");
+
+ if (cm->scan_cb)
+ cm->scan_cb(cm->ctx);
+
+ if ( 0 == cm->enabled ) {
+ return;
+ }
+ select_net(cm);
+}
+
+/**
+ *
+ */
+static void
+wl_media_connected_cb(void* ctx)
+{
+ struct cm *cm = ctx;
+ struct wl_network_t *net = wl_get_current_network();
+ CM_DPRINTF("CM: connected to %s\n", ssid2str(&net->ssid));
+ LINK_LED_ON();
+ ERROR_LED_OFF();
+ if (cm->conn_cb)
+ cm->conn_cb(net, cm->ctx);
+}
+
+
+/**
+ *
+ */
+static void
+wl_conn_failure_cb(void* ctx)
+{
+ struct cm *cm = ctx;
+ CM_DPRINTF("CM: connect failed, scanning\n");
+ ERROR_LED_ON();
+ LINK_LED_OFF();
+
+ if ( 0 == cm->enabled ) {
+ return;
+ }
+ if (wl_scan() != WL_SUCCESS)
+ /* should never happen */
+ CM_DPRINTF("CM: could not start scan after connect fail!\n");
+}
+
+
+/**
+ *
+ */
+static void
+wl_conn_lost_cb(void* ctx)
+{
+ struct cm *cm = ctx;
+ CM_DPRINTF("CM: connection lost, scanning\n");
+ LINK_LED_OFF();
+ if (cm->disconn_cb)
+ cm->disconn_cb(cm->ctx);
+
+ if ( 0 == cm->enabled ) {
+ return;
+ }
+ if (wl_scan() != WL_SUCCESS)
+ /* should never happen */
+ CM_DPRINTF("CM: could not start scan after connect lost!\n");
+}
+
+
+/**
+ *
+ */
+static void
+wl_event_cb(struct wl_event_t event, void* ctx)
+{
+ struct cm *cm = ctx;
+
+ switch (event.id) {
+ case WL_EVENT_MEDIA_CONNECTED:
+ wl_media_connected_cb(cm);
+ break;
+
+ case WL_EVENT_CONN_FAILURE:
+ wl_conn_failure_cb(cm);
+ break;
+
+ case WL_EVENT_MEDIA_DISCONNECTED:
+ CM_DPRINTF("CM: disconnected\n");
+ wl_conn_lost_cb(cm);
+ break;
+
+ case WL_EVENT_SCAN_COMPLETE:
+ wl_scan_complete_cb(cm);
+ break;
+
+ default:
+ CM_DPRINTF("CM: unhandled event\n");
+ };
+}
+
+static struct cm *cm = NULL;
+
+
+/**
+ * Doesn't actually start the CM, just initializing. CM will run whenever
+ * an valid ssid is set through wl_cm_set_network() and wl_cm_start()
+ * has been called.
+ */
+wl_err_t
+wl_cm_init(cm_scan_cb_t scan_cb,
+ cm_conn_cb_t conn_cb,
+ cm_disconn_cb_t disconn_cb,
+ void* ctx)
+{
+ if (cm != NULL)
+ return WL_FAILURE;
+
+ cm = calloc(1, sizeof(struct cm));
+ if (cm == NULL) {
+ CM_DPRINTF("CM: out of memory\n");
+ return WL_FAILURE;
+ }
+
+ if (wl_register_event_cb(wl_event_cb, cm) != WL_SUCCESS) {
+ CM_DPRINTF("CM: could not register event cb\n");
+ return WL_FAILURE;
+ }
+
+ cm->scan_cb = scan_cb;
+ cm->conn_cb = conn_cb;
+ cm->disconn_cb = disconn_cb;
+ cm->enabled = 0;
+ cm->ctx = ctx;
+
+ CM_DPRINTF("CM: initialized\n");
+ return WL_SUCCESS;
+}
+
+wl_err_t
+wl_cm_start(void) {
+ if (NULL == cm)
+ return WL_FAILURE;
+
+ cm->enabled = 1;
+ return WL_SUCCESS;
+}
+
+wl_err_t
+wl_cm_stop(void) {
+ if (NULL == cm)
+ return WL_FAILURE;
+
+ cm->enabled = 0;
+ return WL_SUCCESS;
+}
+
+
+/**
+ * Set the desired network which the connection manager should try to
+ * connect to.
+ *
+ * The ssid and bssid of the desired network should be specified. The ssid and
+ * bssid will be matched against the networks found during scan. If any
+ * parameter is null, it will always match. If both parameters are null,
+ * the first found network will be chosen.
+ *
+ * @param ssid The ssid of the desired network. If null, any ssid will match.
+ * @param bssid The bssid of the desired network. If null, any bssid will match.
+ *
+ */
+wl_err_t
+wl_cm_set_network(struct wl_ssid_t *ssid, struct wl_mac_addr_t *bssid)
+{
+ if (cm == NULL)
+ return WL_FAILURE;
+
+ if (ssid)
+ memcpy(&cm->candidate.ssid, ssid, sizeof(cm->candidate.ssid));
+ else
+ cm->candidate.ssid.len = 0;
+
+ if (bssid)
+ memcpy(&cm->candidate.bssid, bssid,
+ sizeof(cm->candidate.bssid));
+ else
+ memset(&cm->candidate.bssid, 0xff, sizeof(cm->candidate.bssid));
+
+ if (cm->candidate.ssid.len)
+ wl_scan();
+
+ return WL_SUCCESS;
+}
+/*
+ * @}
+ */
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