1 /*
2  * wpa_supplicant - Temporary BSSID blacklist
3  * Copyright (c) 2003-2007, Jouni Malinen <j@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  */
wpa_blacklist_get(struct wpa_supplicant * wpa_s,const u8 * bssid)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  */
wpa_blacklist_add(struct wpa_supplicant * wpa_s,const u8 * bssid)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  */
wpa_blacklist_del(struct wpa_supplicant * wpa_s,const u8 * bssid)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  */
wpa_blacklist_clear(struct wpa_supplicant * wpa_s)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