path: root/service/lib/gscan.cpp

#include <stdint.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netlink/genl/genl.h>
#include <netlink/genl/family.h>
#include <netlink/genl/ctrl.h>
#include <linux/rtnetlink.h>
#include <netpacket/packet.h>
#include <linux/filter.h>
#include <linux/errqueue.h>

#include <linux/pkt_sched.h>
#include <netlink/object-api.h>
#include <netlink/netlink.h>
#include <netlink/socket.h>
#include <netlink-types.h>

#include "nl80211_copy.h"

#include "sync.h"

#define LOG_TAG  "WifiHAL"

#include <utils/Log.h>

#include "wifi_hal.h"
#include "common.h"
#include "cpp_bindings.h"

typedef enum {
    BRCM_RESERVED1,
    BRCM_RESERVED2,
    GSCAN_EVENT_SIGNIFICANT_CHANGE_RESULTS ,
    GSCAN_EVENT_HOTLIST_RESULTS,
    GSCAN_EVENT_SCAN_RESULTS_AVAILABLE,

} GSCAN_EVENT;

typedef enum {

    GSCAN_SUBCMD_GET_CAPABILITIES = ANDROID_NL80211_SUBCMD_GSCAN_RANGE_START,

    GSCAN_SUBCMD_SET_CONFIG,                            /* 0x1001 */

    GSCAN_SUBCMD_SET_SCAN_CONFIG,                       /* 0x1002 */
    GSCAN_SUBCMD_ENABLE_GSCAN,                          /* 0x1003 */
    GSCAN_SUBCMD_GET_SCAN_RESULTS,                      /* 0x1004 */
    GSCAN_SUBCMD_SCAN_RESULTS,                          /* 0x1005 */

    GSCAN_SUBCMD_SET_HOTLIST,                           /* 0x1006 */

    GSCAN_SUBCMD_SET_SIGNIFICANT_CHANGE_CONFIG,         /* 0x1007 */

    /* Add more sub commands here */

    GSCAN_SUBCMD_MAX                                    /* 0x1008 */

} GSCAN_SUB_COMMAND;

typedef enum {

    GSCAN_ATTRIBUTE_NUM_BUCKETS = 10,
    GSCAN_ATTRIBUTE_BASE_PERIOD,
    GSCAN_ATTRIBUTE_BUCKETS,
    GSCAN_ATTRIBUTE_BUCKET_ID,
    GSCAN_ATTRIBUTE_BUCKET_PERIOD,
    GSCAN_ATTRIBUTE_BUCKET_NUM_CHANNELS,
    GSCAN_ATTRIBUTE_BUCKET_CHANNELS,
    GSCAN_ATTRIBUTE_NUM_AP_PER_SCAN,
    GSCAN_ATTRIBUTE_REPORT_THRESHOLD,
    GSCAN_ATTRIBUTE_NUM_SCANS_TO_CACHE,

    GSCAN_ATTRIBUTE_ENABLE_FEATURE = 20,
    GSCAN_ATTRIBUTE_SCAN_RESULTS_COMPLETE,              /* indicates no more results */
    GSCAN_ATTRIBUTE_FLUSH_FEATURE,                      /* Flush all the configs */

    /* remaining reserved for additional attributes */
    GSCAN_ATTRIBUTE_NUM_OF_RESULTS = 30,
    GSCAN_ATTRIBUTE_FLUSH_RESULTS,
    GSCAN_ATTRIBUTE_SCAN_RESULTS,                       /* flat array of wifi_scan_result */
    GSCAN_ATTRIBUTE_SCAN_ID,                            /* indicates scan number */
    GSCAN_ATTRIBUTE_SCAN_FLAGS,                         /* indicates if scan was aborted */
    GSCAN_ATTRIBUTE_AP_FLAGS,                           /* flags on significant change event */

    /* remaining reserved for additional attributes */

    GSCAN_ATTRIBUTE_SSID = 40,
    GSCAN_ATTRIBUTE_BSSID,
    GSCAN_ATTRIBUTE_CHANNEL,
    GSCAN_ATTRIBUTE_RSSI,
    GSCAN_ATTRIBUTE_TIMESTAMP,
    GSCAN_ATTRIBUTE_RTT,
    GSCAN_ATTRIBUTE_RTTSD,

    /* remaining reserved for additional attributes */

    GSCAN_ATTRIBUTE_HOTLIST_BSSIDS = 50,
    GSCAN_ATTRIBUTE_RSSI_LOW,
    GSCAN_ATTRIBUTE_RSSI_HIGH,
    GSCAN_ATTRIBUTE_HOTLIST_ELEM,
    GSCAN_ATTRIBUTE_HOTLIST_FLUSH,

    /* remaining reserved for additional attributes */
    GSCAN_ATTRIBUTE_RSSI_SAMPLE_SIZE = 60,
    GSCAN_ATTRIBUTE_LOST_AP_SAMPLE_SIZE,
    GSCAN_ATTRIBUTE_MIN_BREACHING,
    GSCAN_ATTRIBUTE_SIGNIFICANT_CHANGE_BSSIDS,
    GSCAN_ATTRIBUTE_SIGNIFICANT_CHANGE_FLUSH,

    GSCAN_ATTRIBUTE_MAX

} GSCAN_ATTRIBUTE;

/////////////////////////////////////////////////////////////////////////////

class GetCapabilitiesCommand : public WifiCommand
{
    wifi_gscan_capabilities *mCapabilities;
public:
    GetCapabilitiesCommand(wifi_interface_handle iface, wifi_gscan_capabilities *capabitlites)
        : WifiCommand(iface, 0), mCapabilities(capabitlites)
    {
        memset(mCapabilities, 0, sizeof(*mCapabilities));
    }

    virtual int create() {
        ALOGD("Creating message to get scan capablities; iface = %d", mIfaceInfo->id);

        int ret = mMsg.create(GOOGLE_OUI, GSCAN_SUBCMD_GET_CAPABILITIES);
        if (ret < 0) {
            return ret;
        }

        return ret;
    }

protected:
    virtual int handleResponse(WifiEvent& reply) {

        ALOGD("In GetCapabilities::handleResponse");

        if (reply.get_cmd() != NL80211_CMD_VENDOR) {
            ALOGD("Ignoring reply with cmd = %d", reply.get_cmd());
            return NL_SKIP;
        }

        int id = reply.get_vendor_id();
        int subcmd = reply.get_vendor_subcmd();

        ALOGD("Id = %0x, subcmd = %d", id, subcmd);

        void *data = reply.get_vendor_data();
        int len = reply.get_vendor_data_len();

        if (len == sizeof(*mCapabilities)) {
            ALOGE("Invalid reply length");
            memcpy(mCapabilities, data, len);
        } else {
            ALOGE("Invalid reply length: %d", len);
        }

        return NL_OK;
    }
};


wifi_error wifi_get_gscan_capabilities(wifi_interface_handle handle,
        wifi_gscan_capabilities *capabilities)
{
    GetCapabilitiesCommand command(handle, capabilities);
    return (wifi_error) command.requestResponse();
}

/////////////////////////////////////////////////////////////////////////////

/* helper functions */

static int parseScanResults(wifi_scan_result *results, int num, nlattr *attr)
{
    memset(results, 0, sizeof(wifi_scan_result) * num);

    int i = 0;
    for (nl_iterator it(attr); it.has_next() && i < num; it.next(), i++) {

        int index = it.get_type();
        ALOGI("retrieved scan result %d", index);
        nlattr *sc_data = (nlattr *) it.get_data();
        wifi_scan_result *result = results + i;

        for (nl_iterator it2(sc_data); it2.has_next(); it2.next()) {
            int type = it2.get_type();
            if (type == GSCAN_ATTRIBUTE_SSID) {
                strncpy(result->ssid, (char *) it2.get_data(), it2.get_len());
                result->ssid[it2.get_len()] = 0;
            } else if (type == GSCAN_ATTRIBUTE_BSSID) {
                memcpy(result->bssid, (byte *) it2.get_data(), sizeof(mac_addr));
            } else if (type == GSCAN_ATTRIBUTE_TIMESTAMP) {
                result->ts = it2.get_u64();
            } else if (type == GSCAN_ATTRIBUTE_CHANNEL) {
                result->ts = it2.get_u16();
            } else if (type == GSCAN_ATTRIBUTE_RSSI) {
                result->rssi = it2.get_u8();
            } else if (type == GSCAN_ATTRIBUTE_RTT) {
                result->rtt = it2.get_u64();
            } else if (type == GSCAN_ATTRIBUTE_RTTSD) {
                result->rtt_sd = it2.get_u64();
            }
        }

    }

    if (i >= num) {
        ALOGE("Got too many results; skipping some");
    }

    return i;
}

int createFeatureRequest(WifiRequest& request, int subcmd, int enable) {

    int result = request.create(GOOGLE_OUI, subcmd);
    if (result < 0) {
        return result;
    }

    nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
    result = request.put_u32(GSCAN_ATTRIBUTE_ENABLE_FEATURE, enable);
    if (result < 0) {
        return result;
    }

    request.attr_end(data);
    return WIFI_SUCCESS;
}

/////////////////////////////////////////////////////////////////////////////

class ScanCommand : public WifiCommand
{
    wifi_scan_cmd_params *mParams;
    wifi_scan_result_handler mHandler;
public:
    ScanCommand(wifi_interface_handle iface, int id, wifi_scan_cmd_params *params,
                wifi_scan_result_handler handler)
        : WifiCommand(iface, id), mParams(params), mHandler(handler)
    { }

    int createSetupRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_CONFIG);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u32(GSCAN_ATTRIBUTE_BASE_PERIOD, mParams->base_period);
        if (result < 0) {
            return result;
        }

        result = request.put_u32(GSCAN_ATTRIBUTE_NUM_BUCKETS, mParams->num_buckets);
        if (result < 0) {
            return result;
        }

        for (int i = 0; i < mParams->num_buckets; i++) {
            nlattr * bucket = request.attr_start(i);    // next bucket
            result = request.put_u32(GSCAN_ATTRIBUTE_BUCKET_ID, mParams->buckets[i].bucket);
            if (result < 0) {
                return result;
            }
            result = request.put_u32(GSCAN_ATTRIBUTE_BUCKET_PERIOD, mParams->buckets[i].period);
            if (result < 0) {
                return result;
            }
            result = request.put_u32(GSCAN_ATTRIBUTE_BUCKET_NUM_CHANNELS,
                    mParams->buckets[i].num_channels);
            if (result < 0) {
                return result;
            }

            nlattr *channels = request.attr_start(GSCAN_ATTRIBUTE_BUCKET_CHANNELS);
            for (int j = 0; j < mParams->buckets[i].num_channels; j++) {
                result = request.put_u32(j, mParams->buckets[i].channels[j].channel);
                if (result < 0) {
                    return result;
                }
            }

            request.attr_end(channels);
            request.attr_end(bucket);
        }

        request.attr_end(data);
        return WIFI_SUCCESS;
    }

    int createScanConfigRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_SCAN_CONFIG);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u32(GSCAN_ATTRIBUTE_NUM_AP_PER_SCAN, mParams->max_ap_per_scan);
        if (result < 0) {
            return result;
        }

        result = request.put_u32(GSCAN_ATTRIBUTE_REPORT_THRESHOLD, mParams->report_threshold);
        if (result < 0) {
            return result;
        }

        result = request.put_u32(GSCAN_ATTRIBUTE_NUM_SCANS_TO_CACHE, 3);
        if (result < 0) {
            return result;
        }

        request.attr_end(data);
        return WIFI_SUCCESS;
    }

    int createStartRequest(WifiRequest& request) {
        return createFeatureRequest(request, GSCAN_SUBCMD_ENABLE_GSCAN, 1);
    }

    int createStopRequest(WifiRequest& request) {
        return createFeatureRequest(request, GSCAN_SUBCMD_ENABLE_GSCAN, 0);
    }

    int start() {
        ALOGD("Setting configuration");
        WifiRequest request(familyId(), ifaceId());
        int result = createSetupRequest(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to create setup request; result = %d", result);
            return result;
        }

        result = requestResponse(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to configure setup; result = %d", result);
            return result;
        }

        request.destroy();

        result = createScanConfigRequest(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to create scan config request; result = %d", result);
            return result;
        }

        result = requestResponse(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to configure scan; result = %d", result);
            return result;
        }

        ALOGD("Starting scan");

        result = createStartRequest(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to create start request; result = %d", result);
            return result;
        }

        registerVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SCAN_RESULTS_AVAILABLE);

        result = requestResponse(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to start scan; result = %d", result);
            unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SCAN_RESULTS_AVAILABLE);
            return result;
        }

        return result;
    }

    virtual int cancel() {
        ALOGD("Stopping scan");

        WifiRequest request(familyId(), ifaceId());
        int result = createStopRequest(request);
        if (result != WIFI_SUCCESS) {
            ALOGE("failed to create stop request; result = %d", result);
        } else {
            result = requestResponse(request);
            if (result != WIFI_SUCCESS) {
                ALOGE("failed to stop scan; result = %d", result);
            }
        }

        unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SCAN_RESULTS_AVAILABLE);
        return WIFI_SUCCESS;
    }

    virtual int handleResponse(WifiEvent& reply) {
        /* Nothing to do on response! */
        return NL_SKIP;
    }

    virtual int handleEvent(WifiEvent& event) {
        ALOGI("Got a scan results event");

        event.log();

        nlattr *vendor_data = event.get_attribute(NL80211_ATTR_VENDOR_DATA);
        int len = event.get_vendor_data_len();

        if (vendor_data == NULL || len != 4) {
            ALOGI("No scan results found");
            return NL_SKIP;
        }

        int num = event.get_u32(NL80211_ATTR_VENDOR_DATA);
        ALOGI("Found %d scan results", num);
        (*mHandler.on_scan_results_available)(id(), num);
        return NL_SKIP;
    }
};

wifi_error wifi_start_gscan(
        wifi_request_id id,
        wifi_interface_handle iface,
        wifi_scan_cmd_params params,
        wifi_scan_result_handler handler)
{
    wifi_handle handle = getWifiHandle(iface);

    ALOGD("Starting GScan, halHandle = %p", handle);

    ScanCommand *cmd = new ScanCommand(iface, id, &params, handler);
    wifi_register_cmd(handle, id, cmd);
    return (wifi_error)cmd->start();
}

wifi_error wifi_stop_gscan(wifi_request_id id, wifi_interface_handle iface)
{
    ALOGD("Stopping GScan");
    wifi_handle handle = getWifiHandle(iface);

    WifiCommand *cmd = wifi_unregister_cmd(handle, id);
    if (cmd) {
        cmd->cancel();
        delete cmd;
        return WIFI_SUCCESS;
    }

    return WIFI_ERROR_INVALID_ARGS;
}

/////////////////////////////////////////////////////////////////////////////

class GetScanResultsCommand : public WifiCommand {
    wifi_scan_result *mResults;
    int *mNum;
    int mRetrieved;
    byte mFlush;
    int mCompleted;
public:
    GetScanResultsCommand(wifi_interface_handle iface, byte flush,
            wifi_scan_result *results, int *num)
        : WifiCommand(iface, -1), mResults(results), mNum(num),
                mRetrieved(0), mFlush(flush), mCompleted(0)
    { }

    int createRequest(WifiRequest& request, int num, byte flush) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_GET_SCAN_RESULTS);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u32(GSCAN_ATTRIBUTE_NUM_OF_RESULTS, num);
        if (result < 0) {
            return result;
        }

        result = request.put_u8(GSCAN_ATTRIBUTE_FLUSH_RESULTS, flush);
        if (result < 0) {
            return result;
        }

        request.attr_end(data);
        return WIFI_SUCCESS;
    }

    int execute() {
        WifiRequest request(familyId(), ifaceId());
        ALOGI("retrieving %d scan results", *mNum);

        for (int i = 0; i < 10 && mRetrieved < *mNum; i++) {
            int result = createRequest(request, (*mNum - mRetrieved), mFlush);
            if (result < 0) {
                ALOGE("failed to create request");
                return result;
            }

            int prev_retrieved = mRetrieved;

            result = requestResponse(request);

            if (result != WIFI_SUCCESS) {
                ALOGE("failed to retrieve scan results; result = %d", result);
                return result;
            }

            if (mRetrieved == prev_retrieved || mCompleted) {
                /* no more items left to retrieve */
                break;
            }

            request.destroy();
        }

        ALOGE("GetScanResults read %d results", mRetrieved);
        *mNum = mRetrieved;
        return WIFI_SUCCESS;
    }

    virtual int handleResponse(WifiEvent& reply) {
        ALOGD("In GetScanResultsCommand::handleResponse");

        if (reply.get_cmd() != NL80211_CMD_VENDOR) {
            ALOGD("Ignoring reply with cmd = %d", reply.get_cmd());
            return NL_SKIP;
        }

        int id = reply.get_vendor_id();
        int subcmd = reply.get_vendor_subcmd();

        ALOGD("Id = %0x, subcmd = %d", id, subcmd);

        /*
        if (subcmd != GSCAN_SUBCMD_SCAN_RESULTS) {
            ALOGE("Invalid response to GetScanResultsCommand; ignoring it");
            return NL_SKIP;
        }
        */

        nlattr *vendor_data = reply.get_attribute(NL80211_ATTR_VENDOR_DATA);
        int len = reply.get_vendor_data_len();

        if (vendor_data == NULL || len == 0) {
            ALOGE("no vendor data in GetScanResults response; ignoring it");
            return NL_SKIP;
        }

        for (nl_iterator it(vendor_data); it.has_next(); it.next()) {
            if (it.get_type() == GSCAN_ATTRIBUTE_SCAN_RESULTS_COMPLETE) {
                mCompleted = it.get_u8();
                ALOGI("retrieved mCompleted flag : %d", mCompleted);
            } else if (it.get_type() == GSCAN_ATTRIBUTE_SCAN_RESULTS || it.get_type() == 0) {
                for (nl_iterator it2(it.get()); it2.has_next(); it2.next()) {
                    int scan_id = 0, flags = 0, num = 0;
                    if (it2.get_type() == GSCAN_ATTRIBUTE_SCAN_ID) {
                        scan_id = it.get_u32();
                    } else if (it2.get_type() == GSCAN_ATTRIBUTE_SCAN_FLAGS) {
                        flags = it.get_u8();
                    } else if (it2.get_type() == GSCAN_ATTRIBUTE_NUM_OF_RESULTS) {
                        num = it2.get_u32();
                    } else if (it2.get_type() == GSCAN_ATTRIBUTE_SCAN_RESULTS) {
                        num = it2.get_len() / sizeof(wifi_scan_result);
                        num = min(*mNum - mRetrieved, num);
                        memcpy(mResults + mRetrieved, it2.get_data(),
                                sizeof(wifi_scan_result) * num);
                        ALOGI("Retrieved %d scan results", num);
                        wifi_scan_result *results = (wifi_scan_result *)it2.get_data();
                        for (int i = 0; i < num; i++) {
                            wifi_scan_result *result = results + i;
                            ALOGI("%02d  %-32s  %02x:%02x:%02x:%02x:%02x:%02x", i,
                                result->ssid, result->bssid[0], result->bssid[1], result->bssid[2],
                                result->bssid[3], result->bssid[4], result->bssid[5]);
                        }
                        mRetrieved += num;
                    } else {
                        ALOGW("Ignoring invalid attribute type = %d, size = %d",
                                it.get_type(), it.get_len());
                    }
                }
            } else {
                ALOGW("Ignoring invalid attribute type = %d, size = %d",
                        it.get_type(), it.get_len());
            }
        }

        return NL_OK;
    }
};

wifi_error wifi_get_cached_gscan_results(wifi_interface_handle iface, byte flush,
        wifi_scan_result *results, int *num) {

    ALOGD("Getting cached scan results, iface handle = %p, num = %d", iface, *num);

    GetScanResultsCommand *cmd = new GetScanResultsCommand(iface, flush, results, num);
    return (wifi_error)cmd->execute();
}

/////////////////////////////////////////////////////////////////////////////

class BssidHotlistCommand : public WifiCommand
{
private:
    wifi_bssid_hotlist_params mParams;
    wifi_hotlist_ap_found_handler mHandler;
    static const int MAX_RESULTS = 64;
    wifi_scan_result mResults[MAX_RESULTS];
public:
    BssidHotlistCommand(wifi_interface_handle handle, int id,
            wifi_bssid_hotlist_params params, wifi_hotlist_ap_found_handler handler)
        : WifiCommand(handle, id), mParams(params), mHandler(handler)
    { }

    int createSetupRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_HOTLIST);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u8(GSCAN_ATTRIBUTE_HOTLIST_FLUSH, 1);
        if (result < 0) {
            return result;
        }

        struct nlattr * attr = request.attr_start(GSCAN_ATTRIBUTE_HOTLIST_BSSIDS);
        for (int i = 0; i < mParams.num; i++) {
            nlattr *attr2 = request.attr_start(GSCAN_ATTRIBUTE_HOTLIST_ELEM);
            if (attr2 == NULL) {
                return WIFI_ERROR_OUT_OF_MEMORY;
            }
            result = request.put_addr(GSCAN_ATTRIBUTE_BSSID, mParams.bssids[i].bssid);
            if (result < 0) {
                return result;
            }
            result = request.put_u8(GSCAN_ATTRIBUTE_RSSI_HIGH, mParams.bssids[i].high);
            if (result < 0) {
                return result;
            }
            result = request.put_u8(GSCAN_ATTRIBUTE_RSSI_LOW, mParams.bssids[i].low);
            if (result < 0) {
                return result;
            }
            request.attr_end(attr2);
        }

        request.attr_end(attr);
        request.attr_end(data);
        return result;
    }

    int createTeardownRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_HOTLIST);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u8(GSCAN_ATTRIBUTE_HOTLIST_FLUSH, 1);
        if (result < 0) {
            return result;
        }

        struct nlattr * attr = request.attr_start(GSCAN_ATTRIBUTE_HOTLIST_BSSIDS);
        request.attr_end(attr);
        request.attr_end(data);
        return result;
    }

    int start() {
        ALOGI("Executing hotlist setup request, num = %d", mParams.num);
        WifiRequest request(familyId(), ifaceId());
        int result = createSetupRequest(request);
        if (result < 0) {
            return result;
        }

        result = requestResponse(request);
        if (result < 0) {
            ALOGI("Failed to execute hotlist setup request, result = %d", result);
            unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_HOTLIST_RESULTS);
            return result;
        }

        ALOGI("Successfully set %d APs in the hotlist", mParams.num);
        result = createFeatureRequest(request, GSCAN_SUBCMD_ENABLE_GSCAN, 1);
        if (result < 0) {
            return result;
        }

        registerVendorHandler(GOOGLE_OUI, GSCAN_EVENT_HOTLIST_RESULTS);

        result = requestResponse(request);
        if (result < 0) {
            unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_HOTLIST_RESULTS);
            return result;
        }

        ALOGI("successfully restarted the scan");
        return result;
    }

    virtual int cancel() {
        /* unregister event handler */
        unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_HOTLIST_RESULTS);

        /* create set hotlist message with empty hotlist */
        WifiRequest request(familyId(), ifaceId());
        int result = createTeardownRequest(request);
        if (result < 0) {
            return result;
        }

        result = requestResponse(request);
        if (result < 0) {
            return result;
        }

        ALOGI("Successfully reset APs in current hotlist");
        return result;
    }

    virtual int handleResponse(WifiEvent& reply) {
        /* Nothing to do on response! */
        return NL_SKIP;
    }

    virtual int handleEvent(WifiEvent& event) {
        ALOGI("Got a hotlist ap found event");

        event.log();

        nlattr *vendor_data = event.get_attribute(NL80211_ATTR_VENDOR_DATA);
        int len = event.get_vendor_data_len();

        if (vendor_data == NULL || len == 0) {
            ALOGI("No scan results found");
            return NL_SKIP;
        }

        memset(mResults, 0, sizeof(wifi_scan_result) * MAX_RESULTS);

        int num = len / sizeof(wifi_scan_result);
        num = min(MAX_RESULTS, num);
        memcpy(mResults, event.get_vendor_data(), num * sizeof(wifi_scan_result));
        ALOGI("Retrieved %d hot APs", num);

        (*mHandler.on_hotlist_ap_found)(id(), num, mResults);
        return NL_SKIP;
    }
};

wifi_error wifi_set_bssid_hotlist(wifi_request_id id, wifi_interface_handle iface,
        wifi_bssid_hotlist_params params, wifi_hotlist_ap_found_handler handler)
{
    wifi_handle handle = getWifiHandle(iface);

    BssidHotlistCommand *cmd = new BssidHotlistCommand(iface, id, params, handler);
    wifi_register_cmd(handle, id, cmd);
    return (wifi_error)cmd->start();
}

wifi_error wifi_reset_bssid_hotlist(wifi_request_id id, wifi_interface_handle iface)
{
    wifi_handle handle = getWifiHandle(iface);

    WifiCommand *cmd = wifi_unregister_cmd(handle, id);
    if (cmd) {
        cmd->cancel();
        delete cmd;
        return WIFI_SUCCESS;
    }

    return WIFI_ERROR_INVALID_ARGS;
}


/////////////////////////////////////////////////////////////////////////////

class SignificantWifiChangeCommand : public WifiCommand
{
private:
    wifi_significant_change_params mParams;
    wifi_significant_change_handler mHandler;
    static const int MAX_RESULTS = 64;
    wifi_scan_result mResults[MAX_RESULTS];
public:
    SignificantWifiChangeCommand(wifi_interface_handle handle, int id,
            wifi_significant_change_params params, wifi_significant_change_handler handler)
        : WifiCommand(handle, id), mParams(params), mHandler(handler)
    { }

    int createSetupRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_SIGNIFICANT_CHANGE_CONFIG);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u8(GSCAN_ATTRIBUTE_SIGNIFICANT_CHANGE_FLUSH, 1);
        if (result < 0) {
            return result;
        }
        result = request.put_u16(GSCAN_ATTRIBUTE_RSSI_SAMPLE_SIZE, mParams.rssi_sample_size);
        if (result < 0) {
            return result;
        }
        result = request.put_u16(GSCAN_ATTRIBUTE_LOST_AP_SAMPLE_SIZE, mParams.lost_ap_sample_size);
        if (result < 0) {
            return result;
        }
        result = request.put_u16(GSCAN_ATTRIBUTE_MIN_BREACHING, mParams.min_breaching);
        if (result < 0) {
            return result;
        }

        struct nlattr * attr = request.attr_start(GSCAN_ATTRIBUTE_SIGNIFICANT_CHANGE_BSSIDS);

        for (int i = 0; i < mParams.num; i++) {

            nlattr *attr2 = request.attr_start(i);
            if (attr2 == NULL) {
                return WIFI_ERROR_OUT_OF_MEMORY;
            }
            result = request.put_addr(GSCAN_ATTRIBUTE_BSSID, mParams.bssids[i].bssid);
            if (result < 0) {
                return result;
            }
            result = request.put_u8(GSCAN_ATTRIBUTE_RSSI_HIGH, mParams.bssids[i].high);
            if (result < 0) {
                return result;
            }
            result = request.put_u8(GSCAN_ATTRIBUTE_RSSI_LOW, mParams.bssids[i].low);
            if (result < 0) {
                return result;
            }
            request.attr_end(attr2);
        }

        request.attr_end(attr);
        request.attr_end(data);

        return result;
    }

    int createTeardownRequest(WifiRequest& request) {
        int result = request.create(GOOGLE_OUI, GSCAN_SUBCMD_SET_SIGNIFICANT_CHANGE_CONFIG);
        if (result < 0) {
            return result;
        }

        nlattr *data = request.attr_start(NL80211_ATTR_VENDOR_DATA);
        result = request.put_u16(GSCAN_ATTRIBUTE_SIGNIFICANT_CHANGE_FLUSH, 1);
        if (result < 0) {
            return result;
        }

        request.attr_end(data);
        return result;
    }

    int start() {
        ALOGI("Set significant wifi change config");
        WifiRequest request(familyId(), ifaceId());

        int result = createSetupRequest(request);
        if (result < 0) {
            return result;
        }

        WifiEvent e(request.getMessage());
        e.log();

        result = requestResponse(request);
        if (result < 0) {
            ALOGI("failed to set significant wifi change config %d", result);
            return result;
        }

        ALOGI("successfully set significant wifi change config");

        result = createFeatureRequest(request, GSCAN_SUBCMD_ENABLE_GSCAN, 1);
        if (result < 0) {
            return result;
        }

        registerVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SIGNIFICANT_CHANGE_RESULTS);

        result = requestResponse(request);
        if (result < 0) {
            unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SIGNIFICANT_CHANGE_RESULTS);
            return result;
        }

        ALOGI("successfully restarted the scan");
        return result;
    }

    virtual int cancel() {
        /* unregister event handler */
        unregisterVendorHandler(GOOGLE_OUI, GSCAN_EVENT_SIGNIFICANT_CHANGE_RESULTS);

        /* create set significant change monitor message with empty hotlist */
        WifiRequest request(familyId(), ifaceId());

        int result = createTeardownRequest(request);
        if (result < 0) {
            return result;
        }

        result = requestResponse(request);
        if (result < 0) {
            return result;
        }

        ALOGI("successfully reset significant wifi change config");
        return result;
    }

    virtual int handleResponse(WifiEvent& reply) {
        /* Nothing to do on response! */
        return NL_SKIP;
    }

    virtual int handleEvent(WifiEvent& event) {
        ALOGI("Got a significant wifi change event");

        nlattr *vendor_data = event.get_attribute(NL80211_ATTR_VENDOR_DATA);
        int len = event.get_vendor_data_len();

        if (vendor_data == NULL || len == 0) {
            ALOGI("No scan results found");
            return NL_SKIP;
        }

        typedef struct {
            uint16_t flags;
            uint16_t channel;
            mac_addr bssid;
            byte rssi_history[8];
        } ChangeInfo;

        int num = min(len / sizeof(ChangeInfo), MAX_RESULTS);
        ChangeInfo *ci = (ChangeInfo *)event.get_vendor_data();

        for (int i = 0; i < num; i++) {
            memcpy(mResults[i].bssid, ci[i].bssid, sizeof(mac_addr));
            mResults[i].rssi = ci[i].rssi_history[7];
            mResults[i].channel = ci[i].channel;
        }

        ALOGI("Retrieved %d scan results", num);

        if (num != 0) {
            (*mHandler.on_significant_change)(id(), num, mResults);
        } else {
            ALOGW("No significant change reported");
        }

        return NL_SKIP;
    }
};

wifi_error wifi_set_significant_change_handler(wifi_request_id id, wifi_interface_handle iface,
        wifi_significant_change_params params, wifi_significant_change_handler handler)
{
    wifi_handle handle = getWifiHandle(iface);

    SignificantWifiChangeCommand *cmd = new SignificantWifiChangeCommand(
            iface, id, params, handler);
    wifi_register_cmd(handle, id, cmd);
    return (wifi_error)cmd->start();
}

wifi_error wifi_reset_significant_change_handler(wifi_request_id id, wifi_interface_handle iface)
{
    wifi_handle handle = getWifiHandle(iface);

    WifiCommand *cmd = wifi_unregister_cmd(handle, id);
    if (cmd) {
        cmd->cancel();
        delete cmd;
        return WIFI_SUCCESS;
    }

    return WIFI_ERROR_INVALID_ARGS;
}