fragattacks/wpa_supplicant/blacklist.c
Jouni Malinen f1a5263389 Maintain maximum blacklist count over list clear operations
wpas_connection_failed() uses the blacklist count to figure out a
suitable time to wait for the next scan. This mechanism did not work
properly in cases where the temporary blacklist gets cleared due to no
other BSSes being available. Address this by maintaining an additional
count of blacklisting values over wpa_blacklist_clear() calls. In
addition, add one more step in the count to timeout mapping to go to 10
second interval if more than four failures are seen.

Signed-hostap: Jouni Malinen <j@w1.fi>
2012-11-25 16:20:44 +02:00

142 lines
3.4 KiB
C

/*
* wpa_supplicant - Temporary BSSID blacklist
* Copyright (c) 2003-2007, 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 "wpa_supplicant_i.h"
#include "blacklist.h"
/**
* wpa_blacklist_get - Get the blacklist entry for a BSSID
* @wpa_s: Pointer to wpa_supplicant data
* @bssid: BSSID
* Returns: Matching blacklist entry for the BSSID or %NULL if not found
*/
struct wpa_blacklist * wpa_blacklist_get(struct wpa_supplicant *wpa_s,
const u8 *bssid)
{
struct wpa_blacklist *e;
if (wpa_s == NULL || bssid == NULL)
return NULL;
e = wpa_s->blacklist;
while (e) {
if (os_memcmp(e->bssid, bssid, ETH_ALEN) == 0)
return e;
e = e->next;
}
return NULL;
}
/**
* wpa_blacklist_add - Add an BSSID to the blacklist
* @wpa_s: Pointer to wpa_supplicant data
* @bssid: BSSID to be added to the blacklist
* Returns: Current blacklist count on success, -1 on failure
*
* This function adds the specified BSSID to the blacklist or increases the
* blacklist count if the BSSID was already listed. It should be called when
* an association attempt fails either due to the selected BSS rejecting
* association or due to timeout.
*
* This blacklist is used to force %wpa_supplicant to go through all available
* BSSes before retrying to associate with an BSS that rejected or timed out
* association. It does not prevent the listed BSS from being used; it only
* changes the order in which they are tried.
*/
int wpa_blacklist_add(struct wpa_supplicant *wpa_s, const u8 *bssid)
{
struct wpa_blacklist *e;
if (wpa_s == NULL || bssid == NULL)
return -1;
e = wpa_blacklist_get(wpa_s, bssid);
if (e) {
e->count++;
wpa_printf(MSG_DEBUG, "BSSID " MACSTR " blacklist count "
"incremented to %d",
MAC2STR(bssid), e->count);
return e->count;
}
e = os_zalloc(sizeof(*e));
if (e == NULL)
return -1;
os_memcpy(e->bssid, bssid, ETH_ALEN);
e->count = 1;
e->next = wpa_s->blacklist;
wpa_s->blacklist = e;
wpa_printf(MSG_DEBUG, "Added BSSID " MACSTR " into blacklist",
MAC2STR(bssid));
return e->count;
}
/**
* wpa_blacklist_del - Remove an BSSID from the blacklist
* @wpa_s: Pointer to wpa_supplicant data
* @bssid: BSSID to be removed from the blacklist
* Returns: 0 on success, -1 on failure
*/
int wpa_blacklist_del(struct wpa_supplicant *wpa_s, const u8 *bssid)
{
struct wpa_blacklist *e, *prev = NULL;
if (wpa_s == NULL || bssid == NULL)
return -1;
e = wpa_s->blacklist;
while (e) {
if (os_memcmp(e->bssid, bssid, ETH_ALEN) == 0) {
if (prev == NULL) {
wpa_s->blacklist = e->next;
} else {
prev->next = e->next;
}
wpa_printf(MSG_DEBUG, "Removed BSSID " MACSTR " from "
"blacklist", MAC2STR(bssid));
os_free(e);
return 0;
}
prev = e;
e = e->next;
}
return -1;
}
/**
* wpa_blacklist_clear - Clear the blacklist of all entries
* @wpa_s: Pointer to wpa_supplicant data
*/
void wpa_blacklist_clear(struct wpa_supplicant *wpa_s)
{
struct wpa_blacklist *e, *prev;
int max_count = 0;
e = wpa_s->blacklist;
wpa_s->blacklist = NULL;
while (e) {
if (e->count > max_count)
max_count = e->count;
prev = e;
e = e->next;
wpa_printf(MSG_DEBUG, "Removed BSSID " MACSTR " from "
"blacklist (clear)", MAC2STR(prev->bssid));
os_free(prev);
}
wpa_s->extra_blacklist_count += max_count;
}