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      1 /*
      2  * wpa_supplicant - Temporary BSSID blacklist
      3  * Copyright (c) 2003-2007, Jouni Malinen <j (at) w1.fi>
      4  *
      5  * This software may be distributed under the terms of the BSD license.
      6  * See README for more details.
      7  */
      8 
      9 #include "includes.h"
     10 
     11 #include "common.h"
     12 #include "wpa_supplicant_i.h"
     13 #include "blacklist.h"
     14 
     15 /**
     16  * wpa_blacklist_get - Get the blacklist entry for a BSSID
     17  * @wpa_s: Pointer to wpa_supplicant data
     18  * @bssid: BSSID
     19  * Returns: Matching blacklist entry for the BSSID or %NULL if not found
     20  */
     21 struct wpa_blacklist * wpa_blacklist_get(struct wpa_supplicant *wpa_s,
     22 					 const u8 *bssid)
     23 {
     24 	struct wpa_blacklist *e;
     25 
     26 	if (wpa_s == NULL || bssid == NULL)
     27 		return NULL;
     28 
     29 	e = wpa_s->blacklist;
     30 	while (e) {
     31 		if (os_memcmp(e->bssid, bssid, ETH_ALEN) == 0)
     32 			return e;
     33 		e = e->next;
     34 	}
     35 
     36 	return NULL;
     37 }
     38 
     39 
     40 /**
     41  * wpa_blacklist_add - Add an BSSID to the blacklist
     42  * @wpa_s: Pointer to wpa_supplicant data
     43  * @bssid: BSSID to be added to the blacklist
     44  * Returns: Current blacklist count on success, -1 on failure
     45  *
     46  * This function adds the specified BSSID to the blacklist or increases the
     47  * blacklist count if the BSSID was already listed. It should be called when
     48  * an association attempt fails either due to the selected BSS rejecting
     49  * association or due to timeout.
     50  *
     51  * This blacklist is used to force %wpa_supplicant to go through all available
     52  * BSSes before retrying to associate with an BSS that rejected or timed out
     53  * association. It does not prevent the listed BSS from being used; it only
     54  * changes the order in which they are tried.
     55  */
     56 int wpa_blacklist_add(struct wpa_supplicant *wpa_s, const u8 *bssid)
     57 {
     58 	struct wpa_blacklist *e;
     59 
     60 	if (wpa_s == NULL || bssid == NULL)
     61 		return -1;
     62 
     63 	e = wpa_blacklist_get(wpa_s, bssid);
     64 	if (e) {
     65 		e->count++;
     66 		wpa_printf(MSG_DEBUG, "BSSID " MACSTR " blacklist count "
     67 			   "incremented to %d",
     68 			   MAC2STR(bssid), e->count);
     69 		return e->count;
     70 	}
     71 
     72 	e = os_zalloc(sizeof(*e));
     73 	if (e == NULL)
     74 		return -1;
     75 	os_memcpy(e->bssid, bssid, ETH_ALEN);
     76 	e->count = 1;
     77 	e->next = wpa_s->blacklist;
     78 	wpa_s->blacklist = e;
     79 	wpa_printf(MSG_DEBUG, "Added BSSID " MACSTR " into blacklist",
     80 		   MAC2STR(bssid));
     81 
     82 	return e->count;
     83 }
     84 
     85 
     86 /**
     87  * wpa_blacklist_del - Remove an BSSID from the blacklist
     88  * @wpa_s: Pointer to wpa_supplicant data
     89  * @bssid: BSSID to be removed from the blacklist
     90  * Returns: 0 on success, -1 on failure
     91  */
     92 int wpa_blacklist_del(struct wpa_supplicant *wpa_s, const u8 *bssid)
     93 {
     94 	struct wpa_blacklist *e, *prev = NULL;
     95 
     96 	if (wpa_s == NULL || bssid == NULL)
     97 		return -1;
     98 
     99 	e = wpa_s->blacklist;
    100 	while (e) {
    101 		if (os_memcmp(e->bssid, bssid, ETH_ALEN) == 0) {
    102 			if (prev == NULL) {
    103 				wpa_s->blacklist = e->next;
    104 			} else {
    105 				prev->next = e->next;
    106 			}
    107 			wpa_printf(MSG_DEBUG, "Removed BSSID " MACSTR " from "
    108 				   "blacklist", MAC2STR(bssid));
    109 			os_free(e);
    110 			return 0;
    111 		}
    112 		prev = e;
    113 		e = e->next;
    114 	}
    115 	return -1;
    116 }
    117 
    118 
    119 /**
    120  * wpa_blacklist_clear - Clear the blacklist of all entries
    121  * @wpa_s: Pointer to wpa_supplicant data
    122  */
    123 void wpa_blacklist_clear(struct wpa_supplicant *wpa_s)
    124 {
    125 	struct wpa_blacklist *e, *prev;
    126 	int max_count = 0;
    127 
    128 	e = wpa_s->blacklist;
    129 	wpa_s->blacklist = NULL;
    130 	while (e) {
    131 		if (e->count > max_count)
    132 			max_count = e->count;
    133 		prev = e;
    134 		e = e->next;
    135 		wpa_printf(MSG_DEBUG, "Removed BSSID " MACSTR " from "
    136 			   "blacklist (clear)", MAC2STR(prev->bssid));
    137 		os_free(prev);
    138 	}
    139 
    140 	wpa_s->extra_blacklist_count += max_count;
    141 }
    142