server/SoftapController.cpp

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <linux/wireless.h>

#include <openssl/evp.h>
#include <openssl/sha.h>

#define LOG_TAG "SoftapController"
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <cutils/log.h>
#include <netutils/ifc.h>
#include <private/android_filesystem_config.h>
#include "wifi.h"
#include "ResponseCode.h"

#include "SoftapController.h"
#include <dirent.h>

using android::base::StringPrintf;
using android::base::WriteStringToFile;

#ifdef LIBWPA_CLIENT_EXISTS
#include <dirent.h>
#include "wpa_ctrl.h"
#endif

std:: string hostapd_unix_file(StringPrintf("/data/misc/wifi/hostapd/wlan0"));
#ifdef LIBWPA_CLIENT_EXISTS
static const char HOSTAPD_DHCP_DIR[]    = "/data/misc/dhcp";
#endif
static const char HOSTAPD_CONF_FILE[]    = "/data/misc/wifi/hostapd.conf";
static const char HOSTAPD_BIN_FILE[]    = "/system/bin/hostapd";
static const char HOSTAPD_SOCKETS_DIR[]    = "/data/misc/wifi/hostapd";
static const char WIFI_HOSTAPD_GLOBAL_CTRL_IFACE[] = "/data/misc/wifi/hostapd/global";

SoftapController::SoftapController()
    : mPid(0) {}

SoftapController::~SoftapController() {
}

#ifdef LIBWPA_CLIENT_EXISTS
void *SoftapController::threadStart(void *obj){
    SoftapController *me = reinterpret_cast<SoftapController *>(obj);
    struct wpa_ctrl *ctrl;
    int count = 0;

    ALOGD("SoftapController::threadStart...");

    DIR *dir = NULL;

    dir = opendir(HOSTAPD_SOCKETS_DIR);
    if (NULL == dir && errno == ENOENT) {
        mkdir(HOSTAPD_SOCKETS_DIR, S_IRWXU|S_IRWXG|S_IRWXO);
        chown(HOSTAPD_SOCKETS_DIR, AID_WIFI, AID_WIFI);
        chmod(HOSTAPD_SOCKETS_DIR, S_IRWXU|S_IRWXG);
    } else {
         if (dir != NULL) { /* Directory already exists */
             ALOGD("%s already exists", HOSTAPD_SOCKETS_DIR);
             closedir(dir);
         }
         if (errno == EACCES) {
             ALOGE("Cant open %s , check permissions ", HOSTAPD_SOCKETS_DIR);
         }
    }
    chmod(HOSTAPD_DHCP_DIR, S_IRWXU|S_IRWXG|S_IRWXO);

    ctrl = wpa_ctrl_open2(hostapd_unix_file.c_str(), HOSTAPD_SOCKETS_DIR);
    while (ctrl == NULL) {
        /*
         * Try to connect to hostapd via wpa_ctrl interface.
         * During conneciton process, it is possible that hostapd
         * has station connected to it.
         * Set sleep time to a appropriate value to lower the
         * ratio that miss the STA-CONNECTED msg from hostapd
         */
        usleep(20000);
        ctrl = wpa_ctrl_open2(hostapd_unix_file.c_str(), HOSTAPD_SOCKETS_DIR);
        if (ctrl != NULL || count >= 150) {
            break;
        }
        count ++;
    }
    if (count == 150 && ctrl == NULL) {
        ALOGE("Connection to hostapd Error.");
        return NULL;
    }

    if (wpa_ctrl_attach(ctrl) != 0) {
        wpa_ctrl_close(ctrl);
        ALOGE("Attach to hostapd Error.");
        return NULL;
    }

    while (me->mHostapdFlag) {
        int res = 0;
        char buf[256];
        char dest_str[300];
        while (wpa_ctrl_pending(ctrl)) {
            size_t len = sizeof(buf) - 1;
            res = wpa_ctrl_recv(ctrl, buf, &len);
            if (res == 0) {
                buf[len] = '\0';
                ALOGD("Get event from hostapd (%s)", buf);
                memset(dest_str, 0x0, sizeof(dest_str));
                snprintf(dest_str, sizeof(dest_str), "IfaceMessage active %s", buf);
                me->mSocketClient->sendMsg(ResponseCode::InterfaceMessage, dest_str, false);
            } else {
                break;
            }
        }

        if (res < 0) {
            break;
        }
        sleep(2);
    }

    wpa_ctrl_detach(ctrl);
    wpa_ctrl_close(ctrl);

    ALOGD("SoftapController::threadExit");
    return NULL;
}
#endif

int SoftapController::startSoftap(bool global_ctrl_iface = false, SocketClient *socketClient = NULL,
    const char *ifname = NULL) {
    pid_t pid = 1;
    DIR *dir = NULL;
    int ret;

    mSocketClient = socketClient;
    if (mPid) {
        ALOGE("SoftAP is already running");
        return ResponseCode::SoftapStatusResult;
    }

    if (ensure_entropy_file_exists() < 0) {
        ALOGE("Wi-Fi entropy file was not created");
    }

    if ((pid = fork()) < 0) {
        ALOGE("fork failed (%s)", strerror(errno));
        return ResponseCode::ServiceStartFailed;
    }

    if (!pid) {
        ensure_entropy_file_exists();
        if (global_ctrl_iface) {
            ret = execl(HOSTAPD_BIN_FILE, HOSTAPD_BIN_FILE,
                        "-e", WIFI_ENTROPY_FILE, "-ddd",
                        "-g", WIFI_HOSTAPD_GLOBAL_CTRL_IFACE,
                        HOSTAPD_CONF_FILE, (char *)NULL);
        } else {
            ret = execl(HOSTAPD_BIN_FILE, HOSTAPD_BIN_FILE,
                        "-e", WIFI_ENTROPY_FILE, HOSTAPD_CONF_FILE,
                        (char *)NULL);
        }
        if (ret) {
            ALOGE("execl failed (%s)", strerror(errno));
        }
        ALOGE("SoftAP failed to start");
        return ResponseCode::ServiceStartFailed;
    } else {
        mPid = pid;
        ALOGD("SoftAP started successfully");
        usleep(AP_BSS_START_DELAY);
        dir = opendir(HOSTAPD_SOCKETS_DIR);
        if (NULL == dir && errno == ENOENT) {
            mkdir(HOSTAPD_SOCKETS_DIR, S_IRWXU|S_IRWXG|S_IRWXO);
            chown(HOSTAPD_SOCKETS_DIR, AID_WIFI, AID_WIFI);
            chmod(HOSTAPD_SOCKETS_DIR, S_IRWXU|S_IRWXG);
        } else {
            if (dir != NULL) { /* Directory already exists */
                ALOGD("%s already exists", HOSTAPD_SOCKETS_DIR);
                closedir(dir);
            }
            if (errno == EACCES) {
                ALOGE("Cant open %s , check permissions ", HOSTAPD_SOCKETS_DIR);
            }
        }
        if (ifname != NULL) {
            std:: string wbuf(StringPrintf("/data/misc/wifi/hostapd/%s",ifname));
            hostapd_unix_file = wbuf;
        }
#ifdef LIBWPA_CLIENT_EXISTS
        mHostapdFlag = true;
        if (mSocketClient != NULL) {
            if ((mThreadErr = pthread_create(&mThread, NULL, SoftapController::threadStart, this)) != 0) {
                ALOGE("pthread_create failed for hostapd listen socket (%s)", strerror(errno));
            }
        }
#endif
    }
    return ResponseCode::SoftapStatusResult;
}

int SoftapController::stopSoftap() {

    if (mPid == 0) {
        ALOGE("SoftAP is not running");
        return ResponseCode::SoftapStatusResult;
    }

#ifdef LIBWPA_CLIENT_EXISTS
    mHostapdFlag = false;
    if (mThreadErr == 0) {
        pthread_join(mThread, NULL);
    }
#endif

    ALOGD("Stopping the SoftAP service...");
    kill(mPid, SIGTERM);
    waitpid(mPid, NULL, 0);

    mPid = 0;
    ALOGD("SoftAP stopped successfully");
    usleep(AP_BSS_STOP_DELAY);
    return ResponseCode::SoftapStatusResult;
}

bool SoftapController::isSoftapStarted() {
    return (mPid != 0);
}

/*
 * Arguments:
 *  argv[2] - wlan interface
 *  argv[3] - SSID
 *  argv[4] - Broadcast/Hidden
 *  argv[5] - Channel
 *  argv[6] - Security
 *  argv[7] - Key
 */
int SoftapController::setSoftap(int argc, char *argv[]) {
    int hidden = 0;
    int channel = AP_CHANNEL_DEFAULT;

    if (argc < 5) {
        ALOGE("Softap set is missing arguments. Please use:");
        ALOGE("softap <wlan iface> <SSID> <hidden/broadcast> <channel> <wpa2?-psk|open> <passphrase>");
        return ResponseCode::CommandSyntaxError;
    }

    if (!strcasecmp(argv[4], "hidden"))
        hidden = 1;

    if (argc >= 5) {
        channel = atoi(argv[5]);
        if (channel <= 0)
            channel = AP_CHANNEL_DEFAULT;
    }

    std::string wbuf(StringPrintf("interface=%s\n"
            "driver=nl80211\n"
            "ctrl_interface=/data/misc/wifi/hostapd\n"
            "ssid=%s\n"
            "channel=%d\n"
            "ieee80211n=1\n"
            "hw_mode=%c\n"
            "ignore_broadcast_ssid=%d\n"
            "wowlan_triggers=any\n",
            argv[2], argv[3], channel, (channel <= 14) ? 'g' : 'a', hidden));

    std::string fbuf;
    if (argc > 7) {
        char psk_str[2*SHA256_DIGEST_LENGTH+1];
        if (!strcmp(argv[6], "wpa-psk")) {
            if (!generatePsk(argv[3], argv[7], psk_str)) {
                return ResponseCode::OperationFailed;
            }
            fbuf = StringPrintf("%swpa=3\nwpa_pairwise=TKIP CCMP\nwpa_psk=%s\n", wbuf.c_str(), psk_str);
        } else if (!strcmp(argv[6], "wpa2-psk")) {
            if (!generatePsk(argv[3], argv[7], psk_str)) {
                return ResponseCode::OperationFailed;
            }
            fbuf = StringPrintf("%swpa=2\nrsn_pairwise=CCMP\nwpa_psk=%s\n", wbuf.c_str(), psk_str);
        } else if (!strcmp(argv[6], "open")) {
            fbuf = wbuf;
        }
    } else if (argc > 6) {
        if (!strcmp(argv[6], "open")) {
            fbuf = wbuf;
        }
    } else {
        fbuf = wbuf;
    }

    if (!WriteStringToFile(fbuf, HOSTAPD_CONF_FILE, 0660, AID_SYSTEM, AID_WIFI)) {
        ALOGE("Cannot write to \"%s\": %s", HOSTAPD_CONF_FILE, strerror(errno));
        return ResponseCode::OperationFailed;
    }
    return ResponseCode::SoftapStatusResult;
}

/*
 * Arguments:
 *	argv[2] - interface name
 *	argv[3] - AP or P2P or STA
 */
int SoftapController::fwReloadSoftap(int argc, char *argv[])
{
    char *fwpath = NULL;

    if (argc < 4) {
        ALOGE("SoftAP fwreload is missing arguments. Please use: softap <wlan iface> <AP|P2P|STA>");
        return ResponseCode::CommandSyntaxError;
    }

    if (strcmp(argv[3], "AP") == 0) {
        fwpath = (char *)wifi_get_fw_path(WIFI_GET_FW_PATH_AP);
    } else if (strcmp(argv[3], "P2P") == 0) {
        fwpath = (char *)wifi_get_fw_path(WIFI_GET_FW_PATH_P2P);
    } else if (strcmp(argv[3], "STA") == 0) {
        fwpath = (char *)wifi_get_fw_path(WIFI_GET_FW_PATH_STA);
    } else {
        return ResponseCode::CommandParameterError;
    }
    if (!fwpath) {
        ALOGE("Softap fwReload - NULL path for %s", argv[3]);
        return ResponseCode::SoftapStatusResult;
    }
    if (wifi_change_fw_path((const char *)fwpath)) {
        ALOGE("Softap fwReload failed");
        return ResponseCode::OperationFailed;
    }
    else {
        ALOGD("Softap fwReload - Ok");
    }
    return ResponseCode::SoftapStatusResult;
}

bool SoftapController::generatePsk(char *ssid, char *passphrase, char *psk_str) {
    unsigned char psk[SHA256_DIGEST_LENGTH];

    // Use the PKCS#5 PBKDF2 with 4096 iterations
    if (PKCS5_PBKDF2_HMAC_SHA1(passphrase, strlen(passphrase),
                               reinterpret_cast<const unsigned char *>(ssid),
                               strlen(ssid), 4096, SHA256_DIGEST_LENGTH,
                               psk) != 1) {
        ALOGE("Cannot generate PSK using PKCS#5 PBKDF2");
        return false;
    }

    for (int j=0; j < SHA256_DIGEST_LENGTH; j++) {
        sprintf(&psk_str[j*2], "%02x", psk[j]);
    }

    return true;
}