/src/hostap/wpa_supplicant/gas_query.c

Source
/*
 * Generic advertisement service (GAS) query
 * Copyright (c) 2009, Atheros Communications
 * Copyright (c) 2011-2014, Qualcomm Atheros, Inc.
 * Copyright (c) 2011-2014, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "utils/eloop.h"
#include "common/ieee802_11_defs.h"
#include "common/gas.h"
#include "common/wpa_ctrl.h"
#include "rsn_supp/wpa.h"
#include "wpa_supplicant_i.h"
#include "config.h"
#include "driver_i.h"
#include "offchannel.h"
#include "gas_query.h"


/** GAS query timeout in seconds */
#define GAS_QUERY_TIMEOUT_PERIOD 2

/* GAS query wait-time / duration in ms */
#define GAS_QUERY_WAIT_TIME_INITIAL 1000
#define GAS_QUERY_WAIT_TIME_COMEBACK 150

#define GAS_QUERY_MAX_COMEBACK_DELAY 60000

/**
 * struct gas_query_pending - Pending GAS query
 */
struct gas_query_pending {
  struct dl_list list;
  struct gas_query *gas;
  u8 addr[ETH_ALEN];
  u8 dialog_token;
  u8 next_frag_id;
  unsigned int wait_comeback:1;
  unsigned int offchannel_tx_started:1;
  unsigned int retry:1;
  unsigned int wildcard_bssid:1;
  unsigned int maintain_addr:1;
  unsigned int sent:1;
  unsigned int radio_work_removal_scheduled:1;
  int freq;
  u16 status_code;
  struct wpabuf *req;
  struct wpabuf *adv_proto;
  struct wpabuf *resp;
  struct os_reltime last_oper;
  void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
       enum gas_query_result result,
       const struct wpabuf *adv_proto,
       const struct wpabuf *resp, u16 status_code);
  void *ctx;
  u8 sa[ETH_ALEN];
};

/**
 * struct gas_query - Internal GAS query data
 */
struct gas_query {
  struct wpa_supplicant *wpa_s;
  struct dl_list pending; /* struct gas_query_pending */
  struct gas_query_pending *current;
  struct wpa_radio_work *work;
  struct os_reltime last_mac_addr_rand;
  int last_rand_sa_type;
  u8 rand_addr[ETH_ALEN];
};


static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
static void gas_query_timeout(void *eloop_data, void *user_ctx);
static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx);
static void gas_query_tx_initial_req(struct gas_query *gas,
             struct gas_query_pending *query);
static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst);


static int ms_from_time(struct os_reltime *last)
{
  struct os_reltime now, res;

  os_get_reltime(&now);
  os_reltime_sub(&now, last, &res);
  return res.sec * 1000 + res.usec / 1000;
}


/**
 * gas_query_init - Initialize GAS query component
 * @wpa_s: Pointer to wpa_supplicant data
 * Returns: Pointer to GAS query data or %NULL on failure
 */
struct gas_query * gas_query_init(struct wpa_supplicant *wpa_s)
{
  struct gas_query *gas;

  gas = os_zalloc(sizeof(*gas));
  if (gas == NULL)
    return NULL;

  gas->wpa_s = wpa_s;
  dl_list_init(&gas->pending);

  return gas;
}


static const char * gas_result_txt(enum gas_query_result result)
{
  switch (result) {
  case GAS_QUERY_SUCCESS:
    return "SUCCESS";
  case GAS_QUERY_FAILURE:
    return "FAILURE";
  case GAS_QUERY_TIMEOUT:
    return "TIMEOUT";
  case GAS_QUERY_PEER_ERROR:
    return "PEER_ERROR";
  case GAS_QUERY_INTERNAL_ERROR:
    return "INTERNAL_ERROR";
  case GAS_QUERY_STOPPED:
    return "STOPPED";
  case GAS_QUERY_DELETED_AT_DEINIT:
    return "DELETED_AT_DEINIT";
  }

  return "N/A";
}


static void gas_query_free(struct gas_query_pending *query, int del_list)
{
  struct gas_query *gas = query->gas;

  if (del_list)
    dl_list_del(&query->list);

  if (gas->work && gas->work->ctx == query) {
    radio_work_done(gas->work);
    gas->work = NULL;
  } else if (!query->radio_work_removal_scheduled) {
    radio_remove_pending_work(gas->wpa_s, query);
  }

  eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  eloop_cancel_timeout(gas_query_timeout, gas, query);
  eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);

  wpabuf_free(query->req);
  wpabuf_free(query->adv_proto);
  wpabuf_free(query->resp);
  os_free(query);
}


static void gas_query_done(struct gas_query *gas,
         struct gas_query_pending *query,
         enum gas_query_result result)
{
  wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_DONE "addr=" MACSTR
    " dialog_token=%u freq=%d status_code=%u result=%s",
    MAC2STR(query->addr), query->dialog_token, query->freq,
    query->status_code, gas_result_txt(result));
  if (gas->current == query)
    gas->current = NULL;
  if (query->offchannel_tx_started)
    offchannel_send_action_done(gas->wpa_s);
  dl_list_del(&query->list);
  query->cb(query->ctx, query->addr, query->dialog_token, result,
      query->adv_proto, query->resp, query->status_code);
  gas_query_free(query, 0);
}


/**
 * gas_query_deinit - Deinitialize GAS query component
 * @gas: GAS query data from gas_query_init()
 */
void gas_query_deinit(struct gas_query *gas)
{
  struct gas_query_pending *query, *next;

  if (gas == NULL)
    return;

  dl_list_for_each_safe(query, next, &gas->pending,
            struct gas_query_pending, list)
    gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);

  os_free(gas);
}


static struct gas_query_pending *
gas_query_get_pending(struct gas_query *gas, const u8 *addr, u8 dialog_token)
{
  struct gas_query_pending *q, *alt = NULL;
  struct wpa_supplicant *wpa_s = gas->wpa_s;
  void *ctx = gas->work ? gas->work->ctx : NULL;

  /* Prefer a pending entry that matches with the current radio_work to
   * avoid issues when freeing the pending entry in gas_query_free(). That
   * case should not really happen, but due to the special case for
   * AP MLD MAC address here, a same dialog token value might end up
   * being pending and matching the same query. */
  dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
    if (!q->sent)
      continue;
    if ((ether_addr_equal(q->addr, addr) &&
         q->dialog_token == dialog_token) ||
        (wpa_s->valid_links &&
         ether_addr_equal(wpa_s->ap_mld_addr, addr) &&
         wpas_ap_link_address(wpa_s, q->addr))) {
      if (q == ctx)
        return q;
      if (!alt)
        alt = q;
    }
  }

  return alt;
}


static int gas_query_append(struct gas_query_pending *query, const u8 *data,
          size_t len)
{
  if (wpabuf_resize(&query->resp, len) < 0) {
    wpa_printf(MSG_DEBUG, "GAS: No memory to store the response");
    return -1;
  }
  wpabuf_put_data(query->resp, data, len);
  return 0;
}


static void gas_query_tx_status(struct wpa_supplicant *wpa_s,
        unsigned int freq, const u8 *dst,
        const u8 *src, const u8 *bssid,
        const u8 *data, size_t data_len,
        enum offchannel_send_action_result result)
{
  struct gas_query_pending *query;
  struct gas_query *gas = wpa_s->gas;
  int dur;

  if (gas->current == NULL) {
    wpa_printf(MSG_DEBUG, "GAS: Unexpected TX status: freq=%u dst="
         MACSTR " result=%d - no query in progress",
         freq, MAC2STR(dst), result);
    return;
  }

  query = gas->current;

  dur = ms_from_time(&query->last_oper);
  wpa_printf(MSG_DEBUG, "GAS: TX status: freq=%u dst=" MACSTR
       " result=%d query=%p dialog_token=%u dur=%d ms",
       freq, MAC2STR(dst), result, query, query->dialog_token, dur);
  if (!ether_addr_equal(dst, query->addr)) {
    wpa_printf(MSG_DEBUG, "GAS: TX status for unexpected destination");
    return;
  }
  os_get_reltime(&query->last_oper);

  if (result == OFFCHANNEL_SEND_ACTION_SUCCESS ||
      result == OFFCHANNEL_SEND_ACTION_NO_ACK) {
    eloop_cancel_timeout(gas_query_timeout, gas, query);
    if (result == OFFCHANNEL_SEND_ACTION_NO_ACK) {
      wpa_printf(MSG_DEBUG, "GAS: No ACK to GAS request");
      eloop_register_timeout(0, 250000,
                 gas_query_timeout, gas, query);
    } else {
      eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
                 gas_query_timeout, gas, query);
    }
    if (query->wait_comeback && !query->retry) {
      eloop_cancel_timeout(gas_query_rx_comeback_timeout,
               gas, query);
      eloop_register_timeout(
        0, (GAS_QUERY_WAIT_TIME_COMEBACK + 10) * 1000,
        gas_query_rx_comeback_timeout, gas, query);
    }
  }
  if (result == OFFCHANNEL_SEND_ACTION_FAILED) {
    eloop_cancel_timeout(gas_query_timeout, gas, query);
    eloop_register_timeout(0, 0, gas_query_timeout, gas, query);
  }
}


static int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
      struct wpabuf *req, unsigned int wait_time)
{
  int res, prot = pmf_in_use(gas->wpa_s, query->addr);
  const u8 *bssid;
  const u8 wildcard_bssid[ETH_ALEN] = {
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff
  };

  wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
       "freq=%d prot=%d using src addr " MACSTR,
       MAC2STR(query->addr), (unsigned int) wpabuf_len(req),
       query->freq, prot, MAC2STR(query->sa));
  if (prot) {
    u8 *categ = wpabuf_mhead_u8(req);
    *categ = WLAN_ACTION_PROTECTED_DUAL;
  }
  os_get_reltime(&query->last_oper);
  if (gas->wpa_s->max_remain_on_chan &&
      wait_time > gas->wpa_s->max_remain_on_chan)
    wait_time = gas->wpa_s->max_remain_on_chan;
  if (!query->wildcard_bssid &&
      (!gas->wpa_s->conf->gas_address3 ||
       (gas->wpa_s->current_ssid &&
        gas->wpa_s->wpa_state >= WPA_ASSOCIATED &&
        ether_addr_equal(query->addr, gas->wpa_s->bssid))))
    bssid = query->addr;
  else
    bssid = wildcard_bssid;

  res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
             query->sa, bssid, wpabuf_head(req),
             wpabuf_len(req), wait_time,
             gas_query_tx_status, 0);

  if (res == 0) {
    query->sent = 1;
    query->offchannel_tx_started = 1;
  }
  return res;
}


static void gas_query_tx_comeback_req(struct gas_query *gas,
              struct gas_query_pending *query)
{
  struct wpabuf *req;
  unsigned int wait_time;

  req = gas_build_comeback_req(query->dialog_token);
  if (req == NULL) {
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    return;
  }

  wait_time = (query->retry || !query->offchannel_tx_started) ?
    GAS_QUERY_WAIT_TIME_INITIAL : GAS_QUERY_WAIT_TIME_COMEBACK;

  if (gas_query_tx(gas, query, req, wait_time) < 0) {
    wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
         MACSTR, MAC2STR(query->addr));
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
  }

  wpabuf_free(req);
}


static void gas_query_rx_comeback_timeout(void *eloop_data, void *user_ctx)
{
  struct gas_query *gas = eloop_data;
  struct gas_query_pending *query = user_ctx;
  int dialog_token;

  wpa_printf(MSG_DEBUG,
       "GAS: No response to comeback request received (retry=%u)",
       query->retry);
  if (gas->current != query || query->retry)
    return;
  dialog_token = gas_query_new_dialog_token(gas, query->addr);
  if (dialog_token < 0)
    return;
  wpa_printf(MSG_DEBUG,
       "GAS: Retry GAS query due to comeback response timeout");
  query->retry = 1;
  query->dialog_token = dialog_token;
  *(wpabuf_mhead_u8(query->req) + 2) = dialog_token;
  query->wait_comeback = 0;
  query->next_frag_id = 0;
  wpabuf_free(query->adv_proto);
  query->adv_proto = NULL;
  eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  eloop_cancel_timeout(gas_query_timeout, gas, query);
  gas_query_tx_initial_req(gas, query);
}


static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx)
{
  struct gas_query *gas = eloop_data;
  struct gas_query_pending *query = user_ctx;

  wpa_printf(MSG_DEBUG, "GAS: Comeback timeout for request to " MACSTR,
       MAC2STR(query->addr));
  gas_query_tx_comeback_req(gas, query);
}


static void gas_query_tx_comeback_req_delay(struct gas_query *gas,
              struct gas_query_pending *query,
              u16 comeback_delay)
{
  unsigned int secs, usecs;

  if (comeback_delay > 1 && query->offchannel_tx_started) {
    offchannel_send_action_done(gas->wpa_s);
    query->offchannel_tx_started = 0;
  }

  secs = (comeback_delay * 1024) / 1000000;
  usecs = comeback_delay * 1024 - secs * 1000000;
  wpa_printf(MSG_DEBUG, "GAS: Send comeback request to " MACSTR
       " in %u secs %u usecs", MAC2STR(query->addr), secs, usecs);
  eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
  eloop_register_timeout(secs, usecs, gas_query_tx_comeback_timeout,
             gas, query);
}


static void gas_query_rx_initial(struct gas_query *gas,
         struct gas_query_pending *query,
         const u8 *adv_proto, size_t adv_proto_len,
         const u8 *resp, size_t len, u16 comeback_delay)
{
  wpa_printf(MSG_DEBUG, "GAS: Received initial response from "
       MACSTR " (dialog_token=%u comeback_delay=%u)",
       MAC2STR(query->addr), query->dialog_token, comeback_delay);

  query->adv_proto = wpabuf_alloc_copy(adv_proto, adv_proto_len);
  if (query->adv_proto == NULL) {
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    return;
  }

  if (comeback_delay) {
    eloop_cancel_timeout(gas_query_timeout, gas, query);
    query->wait_comeback = 1;
    gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
    return;
  }

  /* Query was completed without comeback mechanism */
  if (gas_query_append(query, resp, len) < 0) {
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    return;
  }

  gas_query_done(gas, query, GAS_QUERY_SUCCESS);
}


static void gas_query_rx_comeback(struct gas_query *gas,
          struct gas_query_pending *query,
          const u8 *adv_proto, size_t adv_proto_len,
          const u8 *resp, size_t len, u8 frag_id,
          u8 more_frags, u16 comeback_delay)
{
  wpa_printf(MSG_DEBUG, "GAS: Received comeback response from "
       MACSTR " (dialog_token=%u frag_id=%u more_frags=%u "
       "comeback_delay=%u)",
       MAC2STR(query->addr), query->dialog_token, frag_id,
       more_frags, comeback_delay);
  eloop_cancel_timeout(gas_query_rx_comeback_timeout, gas, query);

  if (adv_proto_len != wpabuf_len(query->adv_proto) ||
      os_memcmp(adv_proto, wpabuf_head(query->adv_proto),
          wpabuf_len(query->adv_proto)) != 0) {
    wpa_printf(MSG_DEBUG, "GAS: Advertisement Protocol changed "
         "between initial and comeback response from "
         MACSTR, MAC2STR(query->addr));
    gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
    return;
  }

  if (comeback_delay) {
    if (frag_id) {
      wpa_printf(MSG_DEBUG, "GAS: Invalid comeback response "
           "with non-zero frag_id and comeback_delay "
           "from " MACSTR, MAC2STR(query->addr));
      gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
      return;
    }
    gas_query_tx_comeback_req_delay(gas, query, comeback_delay);
    return;
  }

  if (frag_id != query->next_frag_id) {
    wpa_printf(MSG_DEBUG, "GAS: Unexpected frag_id in response "
         "from " MACSTR, MAC2STR(query->addr));
    if (frag_id + 1 == query->next_frag_id) {
      wpa_printf(MSG_DEBUG, "GAS: Drop frame as possible "
           "retry of previous fragment");
      return;
    }
    gas_query_done(gas, query, GAS_QUERY_PEER_ERROR);
    return;
  }
  query->next_frag_id++;

  if (gas_query_append(query, resp, len) < 0) {
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    return;
  }

  if (more_frags) {
    gas_query_tx_comeback_req(gas, query);
    return;
  }

  gas_query_done(gas, query, GAS_QUERY_SUCCESS);
}


/**
 * gas_query_rx - Indicate reception of a Public Action or Protected Dual frame
 * @gas: GAS query data from gas_query_init()
 * @da: Destination MAC address of the Action frame
 * @sa: Source MAC address of the Action frame
 * @bssid: BSSID of the Action frame
 * @categ: Category of the Action frame
 * @data: Payload of the Action frame
 * @len: Length of @data
 * @freq: Frequency (in MHz) on which the frame was received
 * Returns: 0 if the Public Action frame was a GAS frame or -1 if not
 */
int gas_query_rx(struct gas_query *gas, const u8 *da, const u8 *sa,
     const u8 *bssid, u8 categ, const u8 *data, size_t len,
     int freq)
{
  struct gas_query_pending *query;
  u8 action, dialog_token, frag_id = 0, more_frags = 0;
  u16 comeback_delay, resp_len;
  const u8 *pos, *adv_proto;
  size_t adv_proto_len;
  int prot, pmf;
  unsigned int left;

  if (gas == NULL || len < 4)
    return -1;

  pos = data;
  action = *pos++;
  dialog_token = *pos++;

  if (action != WLAN_PA_GAS_INITIAL_RESP &&
      action != WLAN_PA_GAS_COMEBACK_RESP)
    return -1; /* Not a GAS response */

  prot = categ == WLAN_ACTION_PROTECTED_DUAL;
  pmf = pmf_in_use(gas->wpa_s, sa);
  if (prot && !pmf) {
    wpa_printf(MSG_DEBUG, "GAS: Drop unexpected protected GAS frame when PMF is disabled");
    return 0;
  }
  if (!prot && pmf) {
    wpa_printf(MSG_DEBUG, "GAS: Drop unexpected unprotected GAS frame when PMF is enabled");
    return 0;
  }

  query = gas_query_get_pending(gas, sa, dialog_token);
  if (query == NULL) {
    wpa_printf(MSG_DEBUG, "GAS: No pending query found for " MACSTR
         " dialog token %u", MAC2STR(sa), dialog_token);
    return -1;
  }

  wpa_printf(MSG_DEBUG, "GAS: Response in %d ms from " MACSTR,
       ms_from_time(&query->last_oper), MAC2STR(sa));

  if (query->wait_comeback && action == WLAN_PA_GAS_INITIAL_RESP) {
    wpa_printf(MSG_DEBUG, "GAS: Unexpected initial response from "
         MACSTR " dialog token %u when waiting for comeback "
         "response", MAC2STR(sa), dialog_token);
    return 0;
  }

  if (!query->wait_comeback && action == WLAN_PA_GAS_COMEBACK_RESP) {
    wpa_printf(MSG_DEBUG, "GAS: Unexpected comeback response from "
         MACSTR " dialog token %u when waiting for initial "
         "response", MAC2STR(sa), dialog_token);
    return 0;
  }

  query->status_code = WPA_GET_LE16(pos);
  pos += 2;

  if (query->status_code == WLAN_STATUS_QUERY_RESP_OUTSTANDING &&
      action == WLAN_PA_GAS_COMEBACK_RESP) {
    wpa_printf(MSG_DEBUG, "GAS: Allow non-zero status for outstanding comeback response");
  } else if (query->status_code != WLAN_STATUS_SUCCESS) {
    wpa_printf(MSG_DEBUG, "GAS: Query to " MACSTR " dialog token "
         "%u failed - status code %u",
         MAC2STR(sa), dialog_token, query->status_code);
    gas_query_done(gas, query, GAS_QUERY_FAILURE);
    return 0;
  }

  if (action == WLAN_PA_GAS_COMEBACK_RESP) {
    if (pos + 1 > data + len)
      return 0;
    frag_id = *pos & 0x7f;
    more_frags = (*pos & 0x80) >> 7;
    pos++;
  }

  /* Comeback Delay */
  if (pos + 2 > data + len)
    return 0;
  comeback_delay = WPA_GET_LE16(pos);
  if (comeback_delay > GAS_QUERY_MAX_COMEBACK_DELAY)
    comeback_delay = GAS_QUERY_MAX_COMEBACK_DELAY;
  pos += 2;

  /* Advertisement Protocol element */
  adv_proto = pos;
  left = data + len - adv_proto;
  if (left < 2 || adv_proto[1] > left - 2) {
    wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
         "Protocol element in the response from " MACSTR,
         MAC2STR(sa));
    return 0;
  }

  if (*adv_proto != WLAN_EID_ADV_PROTO) {
    wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
         "Protocol element ID %u in response from " MACSTR,
         *adv_proto, MAC2STR(sa));
    return 0;
  }
  adv_proto_len = 2 + adv_proto[1];
  if (adv_proto_len > (size_t) (data + len - pos))
    return 0; /* unreachable due to an earlier check */

  pos += adv_proto_len;

  /* Query Response Length */
  if (pos + 2 > data + len) {
    wpa_printf(MSG_DEBUG, "GAS: No room for GAS Response Length");
    return 0;
  }
  resp_len = WPA_GET_LE16(pos);
  pos += 2;

  left = data + len - pos;
  if (resp_len > left) {
    wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
         "response from " MACSTR, MAC2STR(sa));
    return 0;
  }

  if (resp_len < left) {
    wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
         "after Query Response from " MACSTR,
         left - resp_len, MAC2STR(sa));
  }

  if (action == WLAN_PA_GAS_COMEBACK_RESP)
    gas_query_rx_comeback(gas, query, adv_proto, adv_proto_len,
              pos, resp_len, frag_id, more_frags,
              comeback_delay);
  else
    gas_query_rx_initial(gas, query, adv_proto, adv_proto_len,
             pos, resp_len, comeback_delay);

  return 0;
}


static void gas_query_timeout(void *eloop_data, void *user_ctx)
{
  struct gas_query *gas = eloop_data;
  struct gas_query_pending *query = user_ctx;

  wpa_printf(MSG_DEBUG, "GAS: No response received for query to " MACSTR
       " dialog token %u",
       MAC2STR(query->addr), query->dialog_token);
  gas_query_done(gas, query, GAS_QUERY_TIMEOUT);
}


static int gas_query_dialog_token_available(struct gas_query *gas,
              const u8 *dst, u8 dialog_token)
{
  struct gas_query_pending *q;
  dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
    if ((!dst || ether_addr_equal(dst, q->addr)) &&
        dialog_token == q->dialog_token)
      return 0;
  }

  return 1;
}


static void gas_query_start_cb(struct wpa_radio_work *work, int deinit)
{
  struct gas_query_pending *query = work->ctx;
  struct gas_query *gas = query->gas;
  struct wpa_supplicant *wpa_s = gas->wpa_s;

  if (deinit) {
    query->radio_work_removal_scheduled = 1;
    if (work->started) {
      gas->work = NULL;
      gas_query_done(gas, query, GAS_QUERY_DELETED_AT_DEINIT);
      return;
    }

    gas_query_free(query, 1);
    return;
  }

  if (!query->maintain_addr && !wpa_s->conf->gas_rand_mac_addr) {
    if (wpas_update_random_addr_disassoc(wpa_s) < 0) {
      wpa_msg(wpa_s, MSG_INFO,
        "Failed to assign random MAC address for GAS");
      query->radio_work_removal_scheduled = 1;
      gas_query_free(query, 1);
      radio_work_done(work);
      return;
    }
    os_memcpy(query->sa, wpa_s->own_addr, ETH_ALEN);
  }

  gas->work = work;
  gas_query_tx_initial_req(gas, query);
}


static void gas_query_tx_initial_req(struct gas_query *gas,
             struct gas_query_pending *query)
{
  if (gas_query_tx(gas, query, query->req,
       GAS_QUERY_WAIT_TIME_INITIAL) < 0) {
    wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
         MACSTR, MAC2STR(query->addr));
    gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
    return;
  }
  gas->current = query;

  wpa_printf(MSG_DEBUG, "GAS: Starting query timeout for dialog token %u",
       query->dialog_token);
  eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0,
             gas_query_timeout, gas, query);
}


static int gas_query_new_dialog_token(struct gas_query *gas, const u8 *dst)
{
  u8 dialog_token;
  int i;

  /* There should never be more than couple active GAS queries in
   * progress, so it should be very likely to find an available dialog
   * token by checking random values. Use a limit on the number of
   * iterations to handle the unexpected case of large number of pending
   * queries cleanly. */
  for (i = 0; i < 256; i++) {
    /* Get a random number and check if it is not used in any
     * pending entry for any peer. */
    if (os_get_random(&dialog_token, sizeof(dialog_token)) < 0)
      break;
    if (gas_query_dialog_token_available(gas, NULL, dialog_token))
      return dialog_token;
  }

  /* In the highly unlikely case there were so many pending queries that
   * no available unused dialog token was available. Try to find one that
   * is unique for this specific peer. */
  for (i = 0; i < 256; i++) {
    /* Get a random number and check if the slot is available */
    if (os_get_random(&dialog_token, sizeof(dialog_token)) < 0)
      break;
    if (gas_query_dialog_token_available(gas, dst, dialog_token))
      return dialog_token;
  }

  /* No dialog token value available */
  return -1;
}


static int gas_query_set_sa(struct gas_query *gas,
          struct gas_query_pending *query)
{
  struct wpa_supplicant *wpa_s = gas->wpa_s;
  struct os_reltime now;

  if (query->maintain_addr ||
      !wpa_s->conf->gas_rand_mac_addr ||
      !(wpa_s->current_bss ?
        (wpa_s->drv_flags &
         WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA_CONNECTED) :
        (wpa_s->drv_flags & WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA))) {
    /* Use own MAC address as the transmitter address */
    wpa_printf(MSG_DEBUG,
         "GAS: Use own MAC address as the transmitter address%s%s%s",
         query->maintain_addr ? " (maintain_addr)" : "",
         !wpa_s->conf->gas_rand_mac_addr ? " (no gas_rand_mac_adr set)" : "",
         !(wpa_s->current_bss ?
           (wpa_s->drv_flags &
            WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA_CONNECTED) :
           (wpa_s->drv_flags &
            WPA_DRIVER_FLAGS_MGMT_TX_RANDOM_TA)) ?
         " (no driver rand capa" : "");
    os_memcpy(query->sa, wpa_s->own_addr, ETH_ALEN);
    return 0;
  }

  os_get_reltime(&now);

  if (wpa_s->conf->gas_rand_mac_addr == gas->last_rand_sa_type &&
      gas->last_mac_addr_rand.sec != 0 &&
      !os_reltime_expired(&now, &gas->last_mac_addr_rand,
        wpa_s->conf->gas_rand_addr_lifetime)) {
    wpa_printf(MSG_DEBUG,
         "GAS: Use the previously selected random transmitter address "
         MACSTR, MAC2STR(gas->rand_addr));
    os_memcpy(query->sa, gas->rand_addr, ETH_ALEN);
    return 0;
  }

  if (wpa_s->conf->gas_rand_mac_addr == 1 &&
      random_mac_addr(gas->rand_addr) < 0) {
    wpa_printf(MSG_ERROR, "GAS: Failed to get random address");
    return -1;
  }

  if (wpa_s->conf->gas_rand_mac_addr == 2 &&
      random_mac_addr_keep_oui(gas->rand_addr) < 0) {
    wpa_printf(MSG_ERROR,
         "GAS: Failed to get random address with same OUI");
    return -1;
  }

  wpa_printf(MSG_DEBUG, "GAS: Use a new random transmitter address "
       MACSTR, MAC2STR(gas->rand_addr));
  os_memcpy(query->sa, gas->rand_addr, ETH_ALEN);
  os_get_reltime(&gas->last_mac_addr_rand);
  gas->last_rand_sa_type = wpa_s->conf->gas_rand_mac_addr;

  return 0;
}


/**
 * gas_query_req - Request a GAS query
 * @gas: GAS query data from gas_query_init()
 * @dst: Destination MAC address for the query
 * @freq: Frequency (in MHz) for the channel on which to send the query
 * @wildcard_bssid: Force use of wildcard BSSID value
 * @maintain_addr: Maintain own MAC address for exchange (i.e., ignore MAC
 *  address randomization rules)
 * @req: GAS query payload (to be freed by gas_query module in case of success
 *  return)
 * @cb: Callback function for reporting GAS query result and response
 * @ctx: Context pointer to use with the @cb call
 * Returns: dialog token (>= 0) on success or -1 on failure
 */
int gas_query_req(struct gas_query *gas, const u8 *dst, int freq,
      int wildcard_bssid, int maintain_addr, struct wpabuf *req,
      void (*cb)(void *ctx, const u8 *dst, u8 dialog_token,
           enum gas_query_result result,
           const struct wpabuf *adv_proto,
           const struct wpabuf *resp, u16 status_code),
      void *ctx)
{
  struct gas_query_pending *query;
  int dialog_token;

  if (wpabuf_len(req) < 3)
    return -1;

  dialog_token = gas_query_new_dialog_token(gas, dst);
  if (dialog_token < 0)
    return -1;

  query = os_zalloc(sizeof(*query));
  if (query == NULL)
    return -1;

  query->gas = gas;
  query->maintain_addr = !!maintain_addr;
  if (gas_query_set_sa(gas, query)) {
    os_free(query);
    return -1;
  }
  os_memcpy(query->addr, dst, ETH_ALEN);
  query->dialog_token = dialog_token;
  query->wildcard_bssid = !!wildcard_bssid;
  query->freq = freq;
  query->cb = cb;
  query->ctx = ctx;
  query->req = req;
  dl_list_add(&gas->pending, &query->list);

  *(wpabuf_mhead_u8(req) + 2) = dialog_token;

  wpa_msg(gas->wpa_s, MSG_INFO, GAS_QUERY_START "addr=" MACSTR
    " dialog_token=%u freq=%d",
    MAC2STR(query->addr), query->dialog_token, query->freq);

  if (radio_add_work(gas->wpa_s, freq, "gas-query", 0, gas_query_start_cb,
         query) < 0) {
    query->req = NULL; /* caller will free this in error case */
    gas_query_free(query, 1);
    return -1;
  }

  return dialog_token;
}


int gas_query_stop(struct gas_query *gas, u8 dialog_token)
{
  struct gas_query_pending *query;

  dl_list_for_each(query, &gas->pending, struct gas_query_pending, list) {
    if (query->dialog_token == dialog_token) {
      if (!gas->work) {
        /* The pending radio work has not yet been
         * started, but the pending entry has a
         * reference to the soon to be freed query.
         * Need to remove that radio work now to avoid
         * leaving behind a reference to freed memory.
         */
        radio_remove_pending_work(gas->wpa_s, query);
      }
      gas_query_done(gas, query, GAS_QUERY_STOPPED);
      return 0;
    }
  }

  return -1;
}

Coverage Report

Created: 2025-10-10 06:31