hostap/wpa_supplicant/gas_query.c
Jouni Malinen f65f539d9a GAS: Reduce query timeout to two seconds
The five second timeout for GAS queries is excessive and can result in
long waits in cases where APs are either misconfigured or frames are
lost.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
2013-05-20 11:09:34 +03:00

528 lines
14 KiB
C

/*
* Generic advertisement service (GAS) query
* Copyright (c) 2009, Atheros Communications
* Copyright (c) 2011, Qualcomm Atheros
*
* 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 "wpa_supplicant_i.h"
#include "driver_i.h"
#include "offchannel.h"
#include "gas_query.h"
/** GAS query timeout in seconds */
#define GAS_QUERY_TIMEOUT_PERIOD 2
/**
* struct gas_query_pending - Pending GAS query
*/
struct gas_query_pending {
struct dl_list list;
u8 addr[ETH_ALEN];
u8 dialog_token;
u8 next_frag_id;
unsigned int wait_comeback:1;
unsigned int offchannel_tx_started:1;
int freq;
u16 status_code;
struct wpabuf *adv_proto;
struct wpabuf *resp;
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 - Internal GAS query data
*/
struct gas_query {
struct wpa_supplicant *wpa_s;
struct dl_list pending; /* struct gas_query_pending */
};
static void gas_query_tx_comeback_timeout(void *eloop_data, void *user_ctx);
static void gas_query_timeout(void *eloop_data, void *user_ctx);
/**
* 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 void gas_query_done(struct gas_query *gas,
struct gas_query_pending *query,
enum gas_query_result result)
{
if (query->offchannel_tx_started)
offchannel_send_action_done(gas->wpa_s);
eloop_cancel_timeout(gas_query_tx_comeback_timeout, gas, query);
eloop_cancel_timeout(gas_query_timeout, gas, query);
dl_list_del(&query->list);
query->cb(query->ctx, query->addr, query->dialog_token, result,
query->adv_proto, query->resp, query->status_code);
wpabuf_free(query->adv_proto);
wpabuf_free(query->resp);
os_free(query);
}
/**
* 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;
dl_list_for_each(q, &gas->pending, struct gas_query_pending, list) {
if (os_memcmp(q->addr, addr, ETH_ALEN) == 0 &&
q->dialog_token == dialog_token)
return q;
}
return NULL;
}
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 int gas_query_tx(struct gas_query *gas, struct gas_query_pending *query,
struct wpabuf *req)
{
int res;
wpa_printf(MSG_DEBUG, "GAS: Send action frame to " MACSTR " len=%u "
"freq=%d", MAC2STR(query->addr),
(unsigned int) wpabuf_len(req), query->freq);
res = offchannel_send_action(gas->wpa_s, query->freq, query->addr,
gas->wpa_s->own_addr, query->addr,
wpabuf_head(req), wpabuf_len(req), 1000,
NULL, 0);
if (res == 0)
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;
req = gas_build_comeback_req(query->dialog_token);
if (req == NULL) {
gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
return;
}
if (gas_query_tx(gas, query, req) < 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_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;
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, 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, 2 + adv_proto[1]);
if (query->adv_proto == NULL) {
gas_query_done(gas, query, GAS_QUERY_INTERNAL_ERROR);
return;
}
if (comeback_delay) {
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, 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);
if ((size_t) 2 + adv_proto[1] != 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 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
* @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, 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;
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 */
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;
}
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_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);
pos += 2;
/* Advertisement Protocol element */
if (pos + 2 > data + len || pos + 2 + pos[1] > data + len) {
wpa_printf(MSG_DEBUG, "GAS: No room for Advertisement "
"Protocol element in the response from " MACSTR,
MAC2STR(sa));
return 0;
}
if (*pos != WLAN_EID_ADV_PROTO) {
wpa_printf(MSG_DEBUG, "GAS: Unexpected Advertisement "
"Protocol element ID %u in response from " MACSTR,
*pos, MAC2STR(sa));
return 0;
}
adv_proto = pos;
pos += 2 + pos[1];
/* 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;
if (pos + resp_len > data + len) {
wpa_printf(MSG_DEBUG, "GAS: Truncated Query Response in "
"response from " MACSTR, MAC2STR(sa));
return 0;
}
if (pos + resp_len < data + len) {
wpa_printf(MSG_DEBUG, "GAS: Ignore %u octets of extra data "
"after Query Response from " MACSTR,
(unsigned int) (data + len - pos - resp_len),
MAC2STR(sa));
}
if (action == WLAN_PA_GAS_COMEBACK_RESP)
gas_query_rx_comeback(gas, query, adv_proto, pos, resp_len,
frag_id, more_frags, comeback_delay);
else
gas_query_rx_initial(gas, query, adv_proto, 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,
MAC2STR(query->addr));
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 (os_memcmp(dst, q->addr, ETH_ALEN) == 0 &&
dialog_token == q->dialog_token)
return 0;
}
return 1;
}
/**
* 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
* @req: GAS query payload
* @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,
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;
static int next_start = 0;
if (wpabuf_len(req) < 3)
return -1;
for (dialog_token = 0; dialog_token < 256; dialog_token++) {
if (gas_query_dialog_token_available(
gas, dst, (next_start + dialog_token) % 256))
break;
}
if (dialog_token == 256)
return -1; /* Too many pending queries */
dialog_token = (next_start + dialog_token) % 256;
next_start = (dialog_token + 1) % 256;
query = os_zalloc(sizeof(*query));
if (query == NULL)
return -1;
os_memcpy(query->addr, dst, ETH_ALEN);
query->dialog_token = dialog_token;
query->freq = freq;
query->cb = cb;
query->ctx = ctx;
dl_list_add(&gas->pending, &query->list);
*(wpabuf_mhead_u8(req) + 2) = dialog_token;
wpa_printf(MSG_DEBUG, "GAS: Starting request for " MACSTR
" dialog_token %u", MAC2STR(dst), dialog_token);
if (gas_query_tx(gas, query, req) < 0) {
wpa_printf(MSG_DEBUG, "GAS: Failed to send Action frame to "
MACSTR, MAC2STR(query->addr));
dl_list_del(&query->list);
os_free(query);
return -1;
}
eloop_register_timeout(GAS_QUERY_TIMEOUT_PERIOD, 0, gas_query_timeout,
gas, query);
return dialog_token;
}
/**
* gas_query_cancel - Cancel a pending GAS query
* @gas: GAS query data from gas_query_init()
* @dst: Destination MAC address for the query
* @dialog_token: Dialog token from gas_query_req()
*/
void gas_query_cancel(struct gas_query *gas, const u8 *dst, u8 dialog_token)
{
struct gas_query_pending *query;
query = gas_query_get_pending(gas, dst, dialog_token);
if (query)
gas_query_done(gas, query, GAS_QUERY_CANCELLED);
}