root/luci/trunk/contrib/package/iwinfo/src/iwinfo_nl80211.c @ 6606

/*
 * iwinfo - Wireless Information Library - NL80211 Backend
 *
 *   Copyright (C) 2010 Jo-Philipp Wich <xm@subsignal.org>
 *
 * The iwinfo library 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.
 *
 * The iwinfo library 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 the iwinfo library. If not, see http://www.gnu.org/licenses/.
 *
 * The signal handling code is derived from the official madwifi tools,
 * wlanconfig.c in particular. The encryption property handling was
 * inspired by the hostapd madwifi driver.
 *
 * Parts of this code are derived from the Linux iw utility.
 */

#include "iwinfo_nl80211.h"
#include "iwinfo_wext.h"

#define min(x, y) ((x) < (y)) ? (x) : (y)

extern struct iwinfo_iso3166_label ISO3166_Names[];
static struct nl80211_state *nls = NULL;

static int nl80211_init(void)
{
    int err, fd;

    if( !nls )
    {
        nls = malloc(sizeof(struct nl80211_state));
        if( !nls ) {
            err = -ENOMEM;
            goto err;
        }

        nls->nl_sock = nl_socket_alloc();
        if( !nls->nl_sock ) {
            err = -ENOMEM;
            goto err;
        }

        if( genl_connect(nls->nl_sock)) {
            err = -ENOLINK;
            goto err;
        }

        fd = nl_socket_get_fd(nls->nl_sock);
        if( fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC) < 0 )
        {
            err = -EINVAL;
            goto err;
        }

        if( genl_ctrl_alloc_cache(nls->nl_sock, &nls->nl_cache)) {
            err = -ENOMEM;
            goto err;
        }

        nls->nl80211 = genl_ctrl_search_by_name(nls->nl_cache, "nl80211");
        if( !nls->nl80211 )
        {
            err = -ENOENT;
            goto err;
        }
    }

    return 0;


err:
    nl80211_close();
    return err;
}

static int nl80211_msg_error(struct sockaddr_nl *nla,
    struct nlmsgerr *err, void *arg)
{
    int *ret = arg;
    *ret = err->error;
    return NL_STOP;
}

static int nl80211_msg_finish(struct nl_msg *msg, void *arg)
{
    int *ret = arg;
    *ret = 0;
    return NL_SKIP;
}

static int nl80211_msg_ack(struct nl_msg *msg, void *arg)
{
    int *ret = arg;
    *ret = 0;
    return NL_STOP;
}

static int nl80211_msg_response(struct nl_msg *msg, void *arg)
{
    struct nl80211_msg_conveyor *cv = arg;

    nlmsg_get(msg);

    cv->msg = msg;
    cv->hdr = nlmsg_data(nlmsg_hdr(cv->msg));

    nla_parse(cv->attr, NL80211_ATTR_MAX,
        genlmsg_attrdata(cv->hdr, 0),
        genlmsg_attrlen(cv->hdr, 0), NULL);

    return NL_SKIP;
}

static void nl80211_free(struct nl80211_msg_conveyor *cv)
{
    if( cv )
    {
        if( cv->cb )
            nl_cb_put(cv->cb);

        if( cv->msg )
            nlmsg_free(cv->msg);

        cv->cb  = NULL;
        cv->msg = NULL;
    }
}

static struct nl80211_msg_conveyor * nl80211_msg(const char *ifname, int cmd, int flags)
{
    static struct nl80211_msg_conveyor cv;

    int ifidx = -1, phyidx = -1;
    struct nl_msg *req = NULL;
    struct nl_cb *cb = NULL;

    if( nl80211_init() < 0 )
        goto err;

    if( !strncmp(ifname, "phy", 3) )
        phyidx = atoi(&ifname[3]);
    else if( !strncmp(ifname, "radio", 5) )
        phyidx = atoi(&ifname[5]);
    else if( !strncmp(ifname, "mon.", 4) )
        ifidx = if_nametoindex(&ifname[4]);
    else
        ifidx = if_nametoindex(ifname);

    if( (ifidx < 0) && (phyidx < 0) )
        return NULL;

    req = nlmsg_alloc();
    if( !req )
        goto err;

    cb = nl_cb_alloc(NL_CB_DEFAULT);
    if( !cb )
        goto err;

    genlmsg_put(req, 0, 0, genl_family_get_id(nls->nl80211), 0,
        flags, cmd, 0);

    if( ifidx > -1 )
        NLA_PUT_U32(req, NL80211_ATTR_IFINDEX, ifidx);

    if( phyidx > -1 )
        NLA_PUT_U32(req, NL80211_ATTR_WIPHY, phyidx);

    nlmsg_get(req);

    cv.msg       = req;
    cv.cb        = cb;
    cv.custom_cb = 0;

    return &cv;

err:
nla_put_failure:
    if( cb )
        nl_cb_put(cb);

    if( req )
        nlmsg_free(req);

    return NULL;
}

static void nl80211_cb(struct nl80211_msg_conveyor *cv,
    int (*cb)(struct nl_msg *, void *), void *arg)
{
    cv->custom_cb = 1;
    nl_cb_set(cv->cb, NL_CB_VALID, NL_CB_CUSTOM, cb, arg);
}

static struct nl80211_msg_conveyor * nl80211_send(struct nl80211_msg_conveyor *cv)
{
    static struct nl80211_msg_conveyor rcv;
    int err = 1;

    if( !cv->custom_cb )
        nl_cb_set(cv->cb, NL_CB_VALID, NL_CB_CUSTOM, nl80211_msg_response, &rcv);

    if( nl_send_auto_complete(nls->nl_sock, cv->msg) < 0 )
        goto err;

    nl_cb_err(cv->cb,               NL_CB_CUSTOM, nl80211_msg_error,  &err);
    nl_cb_set(cv->cb, NL_CB_FINISH, NL_CB_CUSTOM, nl80211_msg_finish, &err);
    nl_cb_set(cv->cb, NL_CB_ACK,    NL_CB_CUSTOM, nl80211_msg_ack,    &err);

    while (err > 0)
        nl_recvmsgs(nls->nl_sock, cv->cb);

    return &rcv;

err:
    nl_cb_put(cv->cb);
    nlmsg_free(cv->msg);

    return NULL;
}

static int nl80211_freq2channel(int freq)
{
    if (freq == 2484)
        return 14;

    if (freq < 2484)
        return (freq - 2407) / 5;

    return (freq / 5) - 1000;
}

static char * nl80211_getval(const char *ifname, const char *buf, const char *key)
{
    int i, len;
    char lkey[64] = { 0 };
    const char *ln = buf;
    static char lval[256] = { 0 };

    int matched_if = ifname ? 0 : 1;


    for( i = 0, len = strlen(buf); i < len; i++ )
    {
        if( !lkey[0] && (buf[i] == ' ' || buf[i] == '\t') )
        {
            ln++;
        }
        else if( !lkey[0] && (buf[i] == '=') )
        {
            if( (&buf[i] - ln) > 0 )
                memcpy(lkey, ln, min(sizeof(lkey) - 1, &buf[i] - ln));
        }
        else if( buf[i] == '\n' )
        {
            if( lkey[0] )
            {
                memcpy(lval, ln + strlen(lkey) + 1,
                    min(sizeof(lval) - 1, &buf[i] - ln - strlen(lkey) - 1));

                if( (ifname != NULL ) &&
                    (!strcmp(lkey, "interface") || !strcmp(lkey, "bss")) )
                {
                    matched_if = !strcmp(lval, ifname);
                }
                else if( matched_if && !strcmp(lkey, key) )
                {
                    return lval;
                }
            }

            ln = &buf[i+1];
            memset(lkey, 0, sizeof(lkey));
            memset(lval, 0, sizeof(lval));
        }
    }

    return NULL;
}

static char * nl80211_ifname2phy(const char *ifname)
{
    static char phy[32] = { 0 };
    struct nl80211_msg_conveyor *req, *res;

    req = nl80211_msg(ifname, NL80211_CMD_GET_WIPHY, 0);
    if( req )
    {
        res = nl80211_send(req);
        if( res )
        {
            if( res->attr[NL80211_ATTR_WIPHY_NAME] )
            {
                snprintf(phy, sizeof(phy), "%s",
                     nla_get_string(res->attr[NL80211_ATTR_WIPHY_NAME]));
            }
            nl80211_free(res);
        }
        nl80211_free(req);
    }

    return phy[0] ? phy : NULL;
}

static char * nl80211_hostapd_info(const char *ifname)
{
    char *phy;
    char path[32] = { 0 };
    static char buf[4096] = { 0 };
    FILE *conf;

    if( (phy = nl80211_ifname2phy(ifname)) != NULL )
    {
        snprintf(path, sizeof(path), "/var/run/hostapd-%s.conf", phy);

        if( (conf = fopen(path, "r")) != NULL )
        {
            fread(buf, sizeof(buf) - 1, 1, conf);
            fclose(conf);

            return buf;
        }
    }

    return NULL;
}

static inline int nl80211_wpactl_recv(int sock, char *buf, int blen)
{
    fd_set rfds;
    struct timeval tv = { 2, 0 };

    FD_ZERO(&rfds);
    FD_SET(sock, &rfds);

    memset(buf, 0, blen);


    if( select(sock + 1, &rfds, NULL, NULL, &tv) < 0 )
        return -1;

    if( !FD_ISSET(sock, &rfds) )
        return -1;

    return recv(sock, buf, blen, 0);
}

static char * nl80211_wpactl_info(const char *ifname, const char *cmd,
                                   const char *event)
{
    int sock = -1;
    char *rv = NULL;
    size_t remote_length, local_length;
    static char buffer[10240] = { 0 };

    struct sockaddr_un local = { 0 };
    struct sockaddr_un remote = { 0 };


    sock = socket(PF_UNIX, SOCK_DGRAM, 0);
    if( sock < 0 )
        return NULL;

    remote.sun_family = AF_UNIX;
    remote_length = sizeof(remote.sun_family) + sprintf(remote.sun_path,
        "/var/run/wpa_supplicant-%s/%s", ifname, ifname);

    if( fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC) < 0 )
        goto out;

    if( connect(sock, (struct sockaddr *) &remote, remote_length) )
        goto out;

    local.sun_family = AF_UNIX;
    local_length = sizeof(local.sun_family) + sprintf(local.sun_path,
        "/var/run/iwinfo-%s-%d", ifname, getpid());

    if( bind(sock, (struct sockaddr *) &local, local_length) )
        goto out;


    send(sock, "ATTACH", 6, 0);

    if( nl80211_wpactl_recv(sock, buffer, sizeof(buffer)) <= 0 )
        goto out;


    send(sock, cmd, strlen(cmd), 0);

    while( 1 )
    {
        if( nl80211_wpactl_recv(sock, buffer, sizeof(buffer)) <= 0 )
        {
            if( event )
                continue;

            break;
        }

        if( (!event && buffer[0] != '<') || strstr(buffer, event) )
            break;
    }

    rv = buffer;

out:
    close(sock);

    if( local.sun_family )
        unlink(local.sun_path);

    return rv;
}

static inline int nl80211_readint(const char *path)
{
    int fd;
    int rv = -1;
    char buffer[16];

    if( (fd = open(path, O_RDONLY)) > -1 )
    {
        if( read(fd, buffer, sizeof(buffer)) > 0 )
            rv = atoi(buffer);

        close(fd);
    }

    return rv;
}

static char * nl80211_phy2ifname(const char *ifname)
{
    int fd, ifidx = -1, cifidx = -1, phyidx = -1;
    char buffer[64];
    static char nif[IFNAMSIZ] = { 0 };

    DIR *d;
    struct dirent *e;

    if( !ifname )
        return NULL;
    else if( !strncmp(ifname, "phy", 3) )
        phyidx = atoi(&ifname[3]);
    else if( !strncmp(ifname, "radio", 5) )
        phyidx = atoi(&ifname[5]);

    if( phyidx > -1 )
    {
        if( (d = opendir("/sys/class/net")) != NULL )
        {
            while( (e = readdir(d)) != NULL )
            {
                snprintf(buffer, sizeof(buffer),
                    "/sys/class/net/%s/phy80211/index", e->d_name);

                if( nl80211_readint(buffer) == phyidx )
                {
                    snprintf(buffer, sizeof(buffer),
                        "/sys/class/net/%s/ifindex", e->d_name);

                    if( (cifidx = nl80211_readint(buffer)) >= 0 &&
                        ((ifidx < 0) || (cifidx < ifidx)) )
                    {
                        ifidx = cifidx;
                        strncpy(nif, e->d_name, sizeof(nif));
                    }
                }
            }

            closedir(d);
        }
    }

    return nif[0] ? nif : NULL;
}

static char * nl80211_ifadd(const char *ifname)
{
    int phyidx;
    char *rv = NULL;
    static char nif[IFNAMSIZ] = { 0 };
    struct nl80211_msg_conveyor *req, *res;

    req = nl80211_msg(ifname, NL80211_CMD_NEW_INTERFACE, 0);
    if( req )
    {
        snprintf(nif, sizeof(nif), "tmp.%s", ifname);

        NLA_PUT_STRING(req->msg, NL80211_ATTR_IFNAME, nif);
        NLA_PUT_U32(req->msg, NL80211_ATTR_IFTYPE, NL80211_IFTYPE_STATION);

        res = nl80211_send(req);
        if( res )
        {
            rv = nif;
            nl80211_free(res);
        }

    nla_put_failure:
        nl80211_free(req);
    }

    return rv;
}

static void nl80211_ifdel(const char *ifname)
{
    struct nl80211_msg_conveyor *req;

    req = nl80211_msg(ifname, NL80211_CMD_DEL_INTERFACE, 0);
    if( req )
    {
        NLA_PUT_STRING(req->msg, NL80211_ATTR_IFNAME, ifname);

        nl80211_free(nl80211_send(req));

    nla_put_failure:
        nl80211_free(req);
    }
}

static void nl80211_hostapd_hup(const char *ifname)
{
    int fd, pid = 0;
    char buf[32];
    char *phy = nl80211_ifname2phy(ifname);

    if( phy )
    {
        snprintf(buf, sizeof(buf), "/var/run/wifi-%s.pid", phy);
        if( (fd = open(buf, O_RDONLY)) > 0 )
        {
            if( read(fd, buf, sizeof(buf)) > 0 )
                pid = atoi(buf);

            close(fd);
        }

        if( pid > 0 )
            kill(pid, 1);
    }
}


int nl80211_probe(const char *ifname)
{
    return !!nl80211_ifname2phy(ifname);
}

void nl80211_close(void)
{
    if( nls )
    {
        if( nls->nl_sock )
            nl_socket_free(nls->nl_sock);

        if( nls->nl_cache )
            nl_cache_free(nls->nl_cache);

        free(nls);
        nls = NULL;
    }
}

int nl80211_get_mode(const char *ifname, char *buf)
{
    return wext_get_mode(ifname, buf);
}

int nl80211_get_ssid(const char *ifname, char *buf)
{
    char *ssid;

    if( !wext_get_ssid(ifname, buf) )
    {
        return 0;
    }
    else if( (ssid = nl80211_hostapd_info(ifname)) &&
             (ssid = nl80211_getval(ifname, ssid, "ssid")) )
    {
        memcpy(buf, ssid, strlen(ssid));
        return 0;
    }

    return -1;
}

int nl80211_get_bssid(const char *ifname, char *buf)
{
    char *bssid;
    unsigned char mac[6];

    if( !wext_get_bssid(ifname, buf) )
    {
        return 0;
    }
    else if( (bssid = nl80211_hostapd_info(ifname)) &&
             (bssid = nl80211_getval(ifname, bssid, "bssid")) )
    {
        mac[0] = strtol(&bssid[0],  NULL, 16);
        mac[1] = strtol(&bssid[3],  NULL, 16);
        mac[2] = strtol(&bssid[6],  NULL, 16);
        mac[3] = strtol(&bssid[9],  NULL, 16);
        mac[4] = strtol(&bssid[12], NULL, 16);
        mac[5] = strtol(&bssid[15], NULL, 16);

        sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X",
            mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);

        return 0;
    }

    return -1;
}

int nl80211_get_channel(const char *ifname, int *buf)
{
    char *first;

    if( !wext_get_channel(ifname, buf) )
        return 0;

    else if( (first = nl80211_phy2ifname(nl80211_ifname2phy(ifname))) != NULL )
        return wext_get_channel(first, buf);

    return -1;
}

int nl80211_get_frequency(const char *ifname, int *buf)
{
    char *first;

    if( !wext_get_frequency(ifname, buf) )
        return 0;

    else if( (first = nl80211_phy2ifname(nl80211_ifname2phy(ifname))) != NULL )
        return wext_get_frequency(first, buf);

    return -1;
}

int nl80211_get_txpower(const char *ifname, int *buf)
{
    return wext_get_txpower(ifname, buf);
}


static int nl80211_get_signal_cb(struct nl_msg *msg, void *arg)
{
    int8_t dbm;
    int16_t mbit;
    struct nl80211_rssi_rate *rr = arg;

    struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
    struct nlattr *attr[NL80211_ATTR_MAX + 1];
    struct nlattr *sinfo[NL80211_STA_INFO_MAX + 1];
    struct nlattr *rinfo[NL80211_RATE_INFO_MAX + 1];

    static struct nla_policy stats_policy[NL80211_STA_INFO_MAX + 1] = {
        [NL80211_STA_INFO_INACTIVE_TIME] = { .type = NLA_U32    },
        [NL80211_STA_INFO_RX_BYTES]      = { .type = NLA_U32    },
        [NL80211_STA_INFO_TX_BYTES]      = { .type = NLA_U32    },
        [NL80211_STA_INFO_RX_PACKETS]    = { .type = NLA_U32    },
        [NL80211_STA_INFO_TX_PACKETS]    = { .type = NLA_U32    },
        [NL80211_STA_INFO_SIGNAL]        = { .type = NLA_U8     },
        [NL80211_STA_INFO_TX_BITRATE]    = { .type = NLA_NESTED },
        [NL80211_STA_INFO_LLID]          = { .type = NLA_U16    },
        [NL80211_STA_INFO_PLID]          = { .type = NLA_U16    },
        [NL80211_STA_INFO_PLINK_STATE]   = { .type = NLA_U8     },
    };

    static struct nla_policy rate_policy[NL80211_RATE_INFO_MAX + 1] = {
        [NL80211_RATE_INFO_BITRATE]      = { .type = NLA_U16  },
        [NL80211_RATE_INFO_MCS]          = { .type = NLA_U8   },
        [NL80211_RATE_INFO_40_MHZ_WIDTH] = { .type = NLA_FLAG },
        [NL80211_RATE_INFO_SHORT_GI]     = { .type = NLA_FLAG },
    };

    nla_parse(attr, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
          genlmsg_attrlen(gnlh, 0), NULL);

    if( attr[NL80211_ATTR_STA_INFO] )
    {
        if( !nla_parse_nested(sinfo, NL80211_STA_INFO_MAX,
                attr[NL80211_ATTR_STA_INFO], stats_policy) )
        {
            if( sinfo[NL80211_STA_INFO_SIGNAL] )
            {
                dbm = nla_get_u8(sinfo[NL80211_STA_INFO_SIGNAL]);
                rr->rssi = rr->rssi ? (int8_t)((rr->rssi + dbm) / 2) : dbm;
            }

            if( sinfo[NL80211_STA_INFO_TX_BITRATE] )
            {
                if( !nla_parse_nested(rinfo, NL80211_RATE_INFO_MAX,
                        sinfo[NL80211_STA_INFO_TX_BITRATE], rate_policy) )
                {
                    if( rinfo[NL80211_RATE_INFO_BITRATE] )
                    {
                        mbit = nla_get_u16(rinfo[NL80211_RATE_INFO_BITRATE]);
                        rr->rate = rr->rate
                            ? (int16_t)((rr->rate + mbit) / 2) : mbit;
                    }
                }
            }
        }
    }

    return NL_SKIP;
}

int nl80211_get_bitrate(const char *ifname, int *buf)
{
    struct nl80211_rssi_rate rr;
    struct nl80211_msg_conveyor *req;

    if( !wext_get_bitrate(ifname, buf) )
        return 0;

    req = nl80211_msg(ifname, NL80211_CMD_GET_STATION, NLM_F_DUMP);
    if( req )
    {
        rr.rssi = 0;
        rr.rate = 0;

        nl80211_cb(req, nl80211_get_signal_cb, &rr);
        nl80211_send(req);
        nl80211_free(req);

        if( rr.rate )
        {
            *buf = (rr.rate * 100);
            return 0;
        }
    }

    return -1;
}

int nl80211_get_signal(const char *ifname, int *buf)
{
    struct nl80211_rssi_rate rr;
    struct nl80211_msg_conveyor *req;

    if( !wext_get_signal(ifname, buf) )
        return 0;

    req = nl80211_msg(ifname, NL80211_CMD_GET_STATION, NLM_F_DUMP);
    if( req )
    {
        rr.rssi = 0;
        rr.rate = 0;

        nl80211_cb(req, nl80211_get_signal_cb, &rr);
        nl80211_send(req);
        nl80211_free(req);

        if( rr.rssi )
        {
            *buf = rr.rssi;
            return 0;
        }
    }

    return -1;
}

static int nl80211_get_noise_cb(struct nl_msg *msg, void *arg)
{
    int8_t *noise = arg;
    struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
    struct nlattr *tb[NL80211_ATTR_MAX + 1];
    struct nlattr *si[NL80211_SURVEY_INFO_MAX + 1];

    static struct nla_policy sp[NL80211_SURVEY_INFO_MAX + 1] = {
        [NL80211_SURVEY_INFO_FREQUENCY] = { .type = NLA_U32 },
        [NL80211_SURVEY_INFO_NOISE]     = { .type = NLA_U8  },
    };

    nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
        genlmsg_attrlen(gnlh, 0), NULL);

    if (!tb[NL80211_ATTR_SURVEY_INFO])
        return NL_SKIP;

    if (nla_parse_nested(si, NL80211_SURVEY_INFO_MAX,
                         tb[NL80211_ATTR_SURVEY_INFO], sp))
        return NL_SKIP;

    if (!si[NL80211_SURVEY_INFO_NOISE])
        return NL_SKIP;

    if (!*noise || si[NL80211_SURVEY_INFO_IN_USE])
        *noise = (int8_t)nla_get_u8(si[NL80211_SURVEY_INFO_NOISE]);

    return NL_SKIP;
}


int nl80211_get_noise(const char *ifname, int *buf)
{
    int8_t noise;
    struct nl80211_msg_conveyor *req;

    req = nl80211_msg(ifname, NL80211_CMD_GET_SURVEY, NLM_F_DUMP);
    if (req)
    {
        noise = 0;

        nl80211_cb(req, nl80211_get_noise_cb, &noise);
        nl80211_send(req);
        nl80211_free(req);

        if (noise)
        {
            *buf = noise;
            return 0;
        }
    }

    return -1;
}

int nl80211_get_quality(const char *ifname, int *buf)
{
    int signal;

    if( wext_get_quality(ifname, buf) )
    {
        *buf = 0;

        if( !nl80211_get_signal(ifname, &signal) )
        {
            /* A positive signal level is usually just a quality
             * value, pass through as-is */
            if( signal >= 0 )
            {
                *buf = signal;
            }

            /* The cfg80211 wext compat layer assumes a signal range
             * of -110 dBm to -40 dBm, the quality value is derived
             * by adding 110 to the signal level */
            else
            {
                if( signal < -110 )
                    signal = -110;
                else if( signal > -40 )
                    signal = -40;

                *buf = (signal + 110);
            }
        }
    }

    return 0;
}

int nl80211_get_quality_max(const char *ifname, int *buf)
{
    if( wext_get_quality_max(ifname, buf) )
        /* The cfg80211 wext compat layer assumes a maximum
         * quality of 70 */
        *buf = 70;

    return 0;
}

int nl80211_get_encryption(const char *ifname, char *buf)
{
    int i;
    char k[9];
    char *val, *res;
    struct iwinfo_crypto_entry *c = (struct iwinfo_crypto_entry *)buf;

    /* Hostapd */
    if( (res = nl80211_hostapd_info(ifname)) )
    {
        if( (val = nl80211_getval(ifname, res, "wpa")) != NULL )
            c->wpa_version = atoi(val);

        val = nl80211_getval(ifname, res, "wpa_key_mgmt");

        if( !val || strstr(val, "PSK") )
            c->auth_suites |= IWINFO_KMGMT_PSK;

        if( val && strstr(val, "EAP") )
            c->auth_suites |= IWINFO_KMGMT_8021x;

        if( val && strstr(val, "NONE") )
            c->auth_suites |= IWINFO_KMGMT_NONE;

        if( (val = nl80211_getval(ifname, res, "wpa_pairwise")) != NULL )
        {
            if( strstr(val, "TKIP") )
                c->pair_ciphers |= IWINFO_CIPHER_TKIP;

            if( strstr(val, "CCMP") )
                c->pair_ciphers |= IWINFO_CIPHER_CCMP;

            if( strstr(val, "NONE") )
                c->pair_ciphers |= IWINFO_CIPHER_NONE;
        }

        if( (val = nl80211_getval(ifname, res, "auth_algs")) != NULL )
        {
            switch(atoi(val)) {
                case 1:
                    c->auth_algs |= IWINFO_AUTH_OPEN;
                    break;

                case 2:
                    c->auth_algs |= IWINFO_AUTH_SHARED;
                    break;

                case 3:
                    c->auth_algs |= IWINFO_AUTH_OPEN;
                    c->auth_algs |= IWINFO_AUTH_SHARED;
                    break;

                default:
                    break;
            }

            for( i = 0; i < 4; i++ )
            {
                snprintf(k, sizeof(k), "wep_key%d", i);

                if( (val = nl80211_getval(ifname, res, k)) )
                {
                    if( (strlen(val) == 5) || (strlen(val) == 10) )
                        c->pair_ciphers |= IWINFO_CIPHER_WEP40;

                    else if( (strlen(val) == 13) || (strlen(val) == 26) )
                        c->pair_ciphers |= IWINFO_CIPHER_WEP104;
                }
            }
        }

        c->group_ciphers = c->pair_ciphers;
        c->enabled = (c->auth_algs || c->auth_suites) ? 1 : 0;

        return 0;
    }

    /* WPA supplicant */
    else if( (res = nl80211_wpactl_info(ifname, "STATUS", NULL)) &&
             (val = nl80211_getval(NULL, res, "pairwise_cipher")) )
    {
        /* WEP */
        if( strstr(val, "WEP") )
        {
            if( strstr(val, "WEP-40") )
                c->pair_ciphers |= IWINFO_CIPHER_WEP40;

            else if( strstr(val, "WEP-104") )
                c->pair_ciphers |= IWINFO_CIPHER_WEP104;

            c->enabled       = 1;
            c->group_ciphers = c->pair_ciphers;

            c->auth_suites |= IWINFO_KMGMT_NONE;
            c->auth_algs   |= IWINFO_AUTH_OPEN; /* XXX: assumption */
        }

        /* WPA */
        else
        {
            if( strstr(val, "TKIP") )
                c->pair_ciphers |= IWINFO_CIPHER_TKIP;

            else if( strstr(val, "CCMP") )
                c->pair_ciphers |= IWINFO_CIPHER_CCMP;

            else if( strstr(val, "NONE") )
                c->pair_ciphers |= IWINFO_CIPHER_NONE;

            else if( strstr(val, "WEP-40") )
                c->pair_ciphers |= IWINFO_CIPHER_WEP40;

            else if( strstr(val, "WEP-104") )
                c->pair_ciphers |= IWINFO_CIPHER_WEP104;


            if( (val = nl80211_getval(NULL, res, "group_cipher")) )
            {
                if( strstr(val, "TKIP") )
                    c->group_ciphers |= IWINFO_CIPHER_TKIP;

                else if( strstr(val, "CCMP") )
                    c->group_ciphers |= IWINFO_CIPHER_CCMP;

                else if( strstr(val, "NONE") )
                    c->group_ciphers |= IWINFO_CIPHER_NONE;

                else if( strstr(val, "WEP-40") )
                    c->group_ciphers |= IWINFO_CIPHER_WEP40;

                else if( strstr(val, "WEP-104") )
                    c->group_ciphers |= IWINFO_CIPHER_WEP104;
            }


            if( (val = nl80211_getval(NULL, res, "key_mgmt")) )
            {
                if( strstr(val, "WPA2") )
                    c->wpa_version = 2;

                else if( strstr(val, "WPA") )
                    c->wpa_version = 1;


                if( strstr(val, "PSK") )
                    c->auth_suites |= IWINFO_KMGMT_PSK;

                else if( strstr(val, "EAP") || strstr(val, "802.1X") )
                    c->auth_suites |= IWINFO_KMGMT_8021x;

                else if( strstr(val, "NONE") )
                    c->auth_suites |= IWINFO_KMGMT_NONE;
            }

            c->enabled = (c->wpa_version && c->auth_suites) ? 1 : 0;
        }

        return 0;
    }

    return -1;
}


static int nl80211_get_assoclist_cb(struct nl_msg *msg, void *arg)
{
    struct nl80211_assoc_count *ac = arg;
    struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
    struct nlattr *attr[NL80211_ATTR_MAX + 1];
    struct nlattr *sinfo[NL80211_STA_INFO_MAX + 1];

    static struct nla_policy stats_policy[NL80211_STA_INFO_MAX + 1] = {
        [NL80211_STA_INFO_INACTIVE_TIME] = { .type = NLA_U32    },
        [NL80211_STA_INFO_RX_BYTES]      = { .type = NLA_U32    },
        [NL80211_STA_INFO_TX_BYTES]      = { .type = NLA_U32    },
        [NL80211_STA_INFO_RX_PACKETS]    = { .type = NLA_U32    },
        [NL80211_STA_INFO_TX_PACKETS]    = { .type = NLA_U32    },
        [NL80211_STA_INFO_SIGNAL]        = { .type = NLA_U8     },
        [NL80211_STA_INFO_TX_BITRATE]    = { .type = NLA_NESTED },
        [NL80211_STA_INFO_LLID]          = { .type = NLA_U16    },
        [NL80211_STA_INFO_PLID]          = { .type = NLA_U16    },
        [NL80211_STA_INFO_PLINK_STATE]   = { .type = NLA_U8     },
    };

    nla_parse(attr, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
        genlmsg_attrlen(gnlh, 0), NULL);

    if( attr[NL80211_ATTR_MAC] )
        memcpy(ac->entry->mac, nla_data(attr[NL80211_ATTR_MAC]), 6);

    if( attr[NL80211_ATTR_STA_INFO] )
    {
        if( !nla_parse_nested(sinfo, NL80211_STA_INFO_MAX,
                attr[NL80211_ATTR_STA_INFO], stats_policy) )
        {
            if( sinfo[NL80211_STA_INFO_SIGNAL] )
                ac->entry->signal = nla_get_u8(sinfo[NL80211_STA_INFO_SIGNAL]);
        }
    }

    ac->entry->noise = ac->noise;
    ac->entry++;
    ac->count++;

    return NL_SKIP;
}

int nl80211_get_assoclist(const char *ifname, char *buf, int *len)
{
    struct nl80211_assoc_count ac;
    struct nl80211_msg_conveyor *req;

    nl80211_get_noise(ifname, &ac.noise);

    req = nl80211_msg(ifname, NL80211_CMD_GET_STATION, NLM_F_DUMP);
    if( req )
    {
        ac.count = 0;
        ac.entry = (struct iwinfo_assoclist_entry *)buf;

        nl80211_cb(req, nl80211_get_assoclist_cb, &ac);
        nl80211_send(req);
        nl80211_free(req);

        *len = (ac.count * sizeof(struct iwinfo_assoclist_entry));
        return 0;
    }

    return -1;
}

int nl80211_get_txpwrlist(const char *ifname, char *buf, int *len)
{
    int ch_cur, ch_cmp, bands_remain, freqs_remain;
    int dbm_max = -1, dbm_cur, dbm_cnt;
    struct nl80211_msg_conveyor *req, *res;
    struct nlattr *bands[NL80211_BAND_ATTR_MAX + 1];
    struct nlattr *freqs[NL80211_FREQUENCY_ATTR_MAX + 1];
    struct nlattr *band, *freq;
    struct iwinfo_txpwrlist_entry entry;

    static struct nla_policy freq_policy[NL80211_FREQUENCY_ATTR_MAX + 1] = {
        [NL80211_FREQUENCY_ATTR_FREQ]         = { .type = NLA_U32  },
        [NL80211_FREQUENCY_ATTR_DISABLED]     = { .type = NLA_FLAG },
        [NL80211_FREQUENCY_ATTR_PASSIVE_SCAN] = { .type = NLA_FLAG },
        [NL80211_FREQUENCY_ATTR_NO_IBSS]      = { .type = NLA_FLAG },
        [NL80211_FREQUENCY_ATTR_RADAR]        = { .type = NLA_FLAG },
        [NL80211_FREQUENCY_ATTR_MAX_TX_POWER] = { .type = NLA_U32  },
    };

    if( nl80211_get_channel(ifname, &ch_cur) )
        ch_cur = 0;

    req = nl80211_msg(ifname, NL80211_CMD_GET_WIPHY, 0);
    if( req )
    {
        res = nl80211_send(req);
        if( res )
        {
            nla_for_each_nested(band,
                res->attr[NL80211_ATTR_WIPHY_BANDS], bands_remain)
            {
                nla_parse(bands, NL80211_BAND_ATTR_MAX, nla_data(band),
                      nla_len(band), NULL);

                nla_for_each_nested(freq,
                    bands[NL80211_BAND_ATTR_FREQS], freqs_remain)
                {
                    nla_parse(freqs, NL80211_FREQUENCY_ATTR_MAX,
                        nla_data(freq), nla_len(freq), freq_policy);

                    ch_cmp = nl80211_freq2channel(
                        nla_get_u32(freqs[NL80211_FREQUENCY_ATTR_FREQ]));

                    if( (!ch_cur || (ch_cmp == ch_cur)) &&
                        freqs[NL80211_FREQUENCY_ATTR_MAX_TX_POWER] )
                    {
                        dbm_max = (int)(0.01 * nla_get_u32(
                            freqs[NL80211_FREQUENCY_ATTR_MAX_TX_POWER]));

                        break;
                    }
                }
            }

            nl80211_free(res);
        }
        nl80211_free(req);
    }

    if( dbm_max > -1 )
    {
        for( dbm_cur = 0, dbm_cnt = 0;
             dbm_cur < dbm_max;
             dbm_cur += 2, dbm_cnt++ )
        {
            entry.dbm = dbm_cur;
            entry.mw  = iwinfo_dbm2mw(dbm_cur);

            memcpy(&buf[dbm_cnt * sizeof(entry)], &entry, sizeof(entry));
        }

        entry.dbm = dbm_max;
        entry.mw  = iwinfo_dbm2mw(dbm_max);

        memcpy(&buf[dbm_cnt * sizeof(entry)], &entry, sizeof(entry));
        dbm_cnt++;

        *len = dbm_cnt * sizeof(entry);
        return 0;
    }

    return -1;
}

static void nl80211_get_scancrypto(const char *spec,
    struct iwinfo_crypto_entry *c)
{
    if( strstr(spec, "WPA") || strstr(spec, "WEP") )
    {
        c->enabled = 1;

        if( strstr(spec, "WPA2-") && strstr(spec, "WPA-") )
            c->wpa_version = 3;

        else if( strstr(spec, "WPA2") )
            c->wpa_version = 2;

        else if( strstr(spec, "WPA") )
            c->wpa_version = 1;

        else if( strstr(spec, "WEP") )
            c->auth_algs = IWINFO_AUTH_OPEN | IWINFO_AUTH_SHARED;


        if( strstr(spec, "PSK") )
            c->auth_suites |= IWINFO_KMGMT_PSK;

        if( strstr(spec, "802.1X") || strstr(spec, "EAP") )
            c->auth_suites |= IWINFO_KMGMT_8021x;

        if( strstr(spec, "WPA-NONE") )
            c->auth_suites |= IWINFO_KMGMT_NONE;


        if( strstr(spec, "TKIP") )
            c->pair_ciphers |= IWINFO_CIPHER_TKIP;

        if( strstr(spec, "CCMP") )
            c->pair_ciphers |= IWINFO_CIPHER_CCMP;

        if( strstr(spec, "WEP-40") )
            c->pair_ciphers |= IWINFO_CIPHER_WEP40;

        if( strstr(spec, "WEP-104") )
            c->pair_ciphers |= IWINFO_CIPHER_WEP104;

        c->group_ciphers = c->pair_ciphers;
    }
    else
    {
        c->enabled = 0;
    }
}

int nl80211_get_scanlist(const char *ifname, char *buf, int *len)
{
    int freq, rssi, qmax, count;
    char *res;
    char ssid[128] = { 0 };
    char bssid[18] = { 0 };
    char cipher[256] = { 0 };

    /* Got a radioX pseudo interface, find some interface on it or create one */
    if( !strncmp(ifname, "radio", 5) )
    {
        /* Reuse existing interface */
        if( (res = nl80211_phy2ifname(ifname)) != NULL )
        {
            return nl80211_get_scanlist(res, buf, len);
        }

        /* Need to spawn a temporary iface for scanning */
        else if( (res = nl80211_ifadd(ifname)) != NULL )
        {
            count = nl80211_get_scanlist(res, buf, len);
            nl80211_ifdel(res);
            return count;
        }
    }

    struct iwinfo_scanlist_entry *e = (struct iwinfo_scanlist_entry *)buf;

    /* WPA supplicant */
    if( (res = nl80211_wpactl_info(ifname, "SCAN", "CTRL-EVENT-SCAN-RESULTS")) )
    {
        if( (res = nl80211_wpactl_info(ifname, "SCAN_RESULTS", NULL)) )
        {
            nl80211_get_quality_max(ifname, &qmax);

            /* skip header line */
            while( *res++ != '\n' );

            count = 0;

            while( sscanf(res, "%17s %d %d %255s%*[ \t]%127[^\n]\n",
                          bssid, &freq, &rssi, cipher, ssid) > 0 )
            {
                /* BSSID */
                e->mac[0] = strtol(&bssid[0],  NULL, 16);
                e->mac[1] = strtol(&bssid[3],  NULL, 16);
                e->mac[2] = strtol(&bssid[6],  NULL, 16);
                e->mac[3] = strtol(&bssid[9],  NULL, 16);
                e->mac[4] = strtol(&bssid[12], NULL, 16);
                e->mac[5] = strtol(&bssid[15], NULL, 16);

                /* SSID */
                memcpy(e->ssid, ssid,
                    min(strlen(ssid), sizeof(e->ssid) - 1));

                /* Mode (assume master) */
                sprintf((char *)e->mode, "Master");

                /* Channel */
                e->channel = nl80211_freq2channel(freq);

                /* Signal */
                e->signal = rssi;

                /* Quality */
                if( rssi < 0 )
                {
                    /* The cfg80211 wext compat layer assumes a signal range
                     * of -110 dBm to -40 dBm, the quality value is derived
                     * by adding 110 to the signal level */
                    if( rssi < -110 )
                        rssi = -110;
                    else if( rssi > -40 )
                        rssi = -40;

                    e->quality = (rssi + 110);
                }
                else
                {
                    e->quality = rssi;
                }

                /* Max. Quality */
                e->quality_max = qmax;

                /* Crypto */
                nl80211_get_scancrypto(cipher, &e->crypto);

                /* advance to next line */
                while( *res && *res++ != '\n' );

                count++;
                e++;

                memset(ssid, 0, sizeof(ssid));
                memset(bssid, 0, sizeof(bssid));
                memset(cipher, 0, sizeof(cipher));
            }

            *len = count * sizeof(struct iwinfo_scanlist_entry);
            return 0;
        }
    }

    /* AP scan */
    else
    {
        /* Got a temp interface, don't create yet another one */
        if( !strncmp(ifname, "tmp.", 4) )
        {
            if( !iwinfo_ifup(ifname) )
                return -1;

            wext_get_scanlist(ifname, buf, len);
            iwinfo_ifdown(ifname);
            return 0;
        }

        /* Spawn a new scan interface */
        else
        {
            if( !(res = nl80211_ifadd(ifname)) )
                goto out;

            if( !iwinfo_ifmac(res) )
                goto out;

            /* if we can take the new interface up, the driver supports an
             * additional interface and there's no need to tear down the ap */
            if( iwinfo_ifup(res) )
            {
                wext_get_scanlist(res, buf, len);
                iwinfo_ifdown(res);
            }

            /* driver cannot create secondary interface, take down ap
             * during scan */
            else if( iwinfo_ifdown(ifname) && iwinfo_ifup(res) )
            {
                wext_get_scanlist(res, buf, len);
                iwinfo_ifdown(res);
                iwinfo_ifup(ifname);
                nl80211_hostapd_hup(ifname);
            }

        out:
            nl80211_ifdel(res);
            return 0;
        }
    }

    return -1;
}

int nl80211_get_freqlist(const char *ifname, char *buf, int *len)
{
    int count = 0, bands_remain, freqs_remain;
    struct nl80211_msg_conveyor *req, *res;
    struct nlattr *bands[NL80211_BAND_ATTR_MAX + 1];
    struct nlattr *freqs[NL80211_FREQUENCY_ATTR_MAX + 1];
    struct nlattr *band, *freq;
    struct iwinfo_freqlist_entry *e = (struct iwinfo_freqlist_entry *)buf;

    req = nl80211_msg(ifname, NL80211_CMD_GET_WIPHY, 0);
    if( req )
    {
        res = nl80211_send(req);
        if( res )
        {
            nla_for_each_nested(band,
                res->attr[NL80211_ATTR_WIPHY_BANDS], bands_remain)
            {
                nla_parse(bands, NL80211_BAND_ATTR_MAX, nla_data(band),
                      nla_len(band), NULL);

                nla_for_each_nested(freq,
                    bands[NL80211_BAND_ATTR_FREQS], freqs_remain)
                {
                    nla_parse(freqs, NL80211_FREQUENCY_ATTR_MAX,
                        nla_data(freq), nla_len(freq), NULL);

                    if( !freqs[NL80211_FREQUENCY_ATTR_FREQ] ||
                        freqs[NL80211_FREQUENCY_ATTR_DISABLED] )
                        continue;

                    e->mhz = nla_get_u32(freqs[NL80211_FREQUENCY_ATTR_FREQ]);
                    e->channel = nl80211_freq2channel(e->mhz);

                    e->restricted = (
                        freqs[NL80211_FREQUENCY_ATTR_PASSIVE_SCAN] ||
                        freqs[NL80211_FREQUENCY_ATTR_NO_IBSS]      ||
                        freqs[NL80211_FREQUENCY_ATTR_RADAR]
                    ) ? 1 : 0;

                    e++;
                    count++;
                }
            }
            nl80211_free(res);
        }
        nl80211_free(req);
    }

    if( count > 0 )
    {
        *len = count * sizeof(struct iwinfo_freqlist_entry);
        return 0;
    }

    return -1;
}

int nl80211_get_country(const char *ifname, char *buf)
{
    int rv = -1;
    struct nl80211_msg_conveyor *req, *res;

    req = nl80211_msg(ifname, NL80211_CMD_GET_REG, 0);
    if( req )
    {
        res = nl80211_send(req);
        if( res )
        {
            if( res->attr[NL80211_ATTR_REG_ALPHA2] )
            {
                memcpy(buf, nla_data(res->attr[NL80211_ATTR_REG_ALPHA2]), 2);
                rv = 0;
            }
            nl80211_free(res);
        }
        nl80211_free(req);
    }

    return rv;
}

int nl80211_get_countrylist(const char *ifname, char *buf, int *len)
{
    int i, count;
    struct iwinfo_iso3166_label *l;
    struct iwinfo_country_entry *e = (struct iwinfo_country_entry *)buf;

    for( l = ISO3166_Names, count = 0; l->iso3166; l++, e++, count++ )
    {
        e->iso3166 = l->iso3166;
        e->ccode[0] = (l->iso3166 / 256);
        e->ccode[1] = (l->iso3166 % 256);
    }

    *len = (count * sizeof(struct iwinfo_country_entry));
    return 0;
}

int nl80211_get_hwmodelist(const char *ifname, int *buf)
{
    int bands_remain, freqs_remain;
    struct nl80211_msg_conveyor *req, *res;
    struct nlattr *bands[NL80211_BAND_ATTR_MAX + 1];
    struct nlattr *freqs[NL80211_FREQUENCY_ATTR_MAX + 1];
    struct nlattr *band, *freq;
    uint16_t caps = 0;

    req = nl80211_msg(ifname, NL80211_CMD_GET_WIPHY, 0);
    if( req )
    {
        res = nl80211_send(req);
        if( res )
        {
            nla_for_each_nested(band,
                res->attr[NL80211_ATTR_WIPHY_BANDS], bands_remain)
            {
                nla_parse(bands, NL80211_BAND_ATTR_MAX, nla_data(band),
                      nla_len(band), NULL);

                if( bands[NL80211_BAND_ATTR_HT_CAPA] )
                    caps = nla_get_u16(bands[NL80211_BAND_ATTR_HT_CAPA]);

                /* Treat any nonzero capability as 11n */
                if( caps > 0 )
                    *buf |= IWINFO_80211_N;

                nla_for_each_nested(freq,
                    bands[NL80211_BAND_ATTR_FREQS], freqs_remain)
                {
                    nla_parse(freqs, NL80211_FREQUENCY_ATTR_MAX,
                        nla_data(freq), nla_len(freq), NULL);

                    if( !freqs[NL80211_FREQUENCY_ATTR_FREQ] )
                        continue;

                    if( nla_get_u32(freqs[NL80211_FREQUENCY_ATTR_FREQ]) < 2485 )
                    {
                        *buf |= IWINFO_80211_B;
                        *buf |= IWINFO_80211_G;
                    }
                    else
                    {
                        *buf |= IWINFO_80211_A;
                    }
                }
            }
            nl80211_free(res);
        }
        nl80211_free(req);
    }

    return *buf ? 0 : -1;
}

int nl80211_get_mbssid_support(const char *ifname, int *buf)
{
    /* Test whether we can create another interface */
    char *nif = nl80211_ifadd(ifname);

    if( nif )
    {
        *buf = (iwinfo_ifmac(nif) && iwinfo_ifup(nif));

        iwinfo_ifdown(nif);
        nl80211_ifdel(nif);

        return 0;
    }

    return -1;
}