1 /*
2 * libwebsockets - lws_netdev_wifi generic state handling
3 *
4 * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 *
24 * The generic wifi netdevs follow a
25 */
26
27 #include "private-lib-core.h"
28
29 int
lws_netdev_wifi_rssi_sort_compare(const lws_dll2_t * d,const lws_dll2_t * i)30 lws_netdev_wifi_rssi_sort_compare(const lws_dll2_t *d, const lws_dll2_t *i)
31 {
32 const lws_wifi_sta_t *wsd = (const lws_wifi_sta_t *)d,
33 *wsi = (const lws_wifi_sta_t *)i;
34 return rssi_averaged(wsd) > rssi_averaged(wsi);
35 }
36
37 void
lws_netdev_wifi_scan_empty(lws_netdev_instance_wifi_t * wnd)38 lws_netdev_wifi_scan_empty(lws_netdev_instance_wifi_t *wnd)
39 {
40 lws_start_foreach_dll_safe(struct lws_dll2 *, p, p1, lws_dll2_get_head(
41 &wnd->scan)) {
42 lws_wifi_sta_t *s = lws_container_of(p, lws_wifi_sta_t, list);
43
44 lws_dll2_remove(p);
45 lws_free(s);
46
47 } lws_end_foreach_dll_safe(p, p1);
48 }
49
50 void
lws_netdev_wifi_scan(lws_sorted_usec_list_t * sul)51 lws_netdev_wifi_scan(lws_sorted_usec_list_t *sul)
52 {
53 lws_netdev_instance_wifi_t *wnd = lws_container_of(sul,
54 lws_netdev_instance_wifi_t, sul_scan);
55
56 wnd->inst.ops->scan(&wnd->inst);
57 }
58
59 lws_wifi_sta_t *
lws_netdev_wifi_scan_find(lws_netdev_instance_wifi_t * wnd,const char * ssid,const uint8_t * bssid)60 lws_netdev_wifi_scan_find(lws_netdev_instance_wifi_t *wnd, const char *ssid,
61 const uint8_t *bssid)
62 {
63 lws_start_foreach_dll(struct lws_dll2 *, p, lws_dll2_get_head(
64 &wnd->scan)) {
65 lws_wifi_sta_t *w = lws_container_of(p, lws_wifi_sta_t, list);
66
67 if (!strcmp(ssid, (const char *)&w[1]) &&
68 !memcmp(bssid, w->bssid, 6))
69 return w;
70
71 } lws_end_foreach_dll(p);
72
73 return NULL;
74 }
75
76 int
lws_netdev_wifi_scan_select(lws_netdev_instance_wifi_t * wnd)77 lws_netdev_wifi_scan_select(lws_netdev_instance_wifi_t *wnd)
78 {
79 lws_netdevs_t *netdevs = lws_netdevs_from_ndi(&wnd->inst);
80 struct lws_context *cx = lws_context_from_netdevs(netdevs);
81 uint32_t least_recent = 0xffffffff;
82 lws_wifi_creds_t *pc = NULL;
83 lws_wifi_sta_t *pw = NULL;
84
85 /*
86 * Trim enough of the lowest RSSI guys in order to get us below the
87 * limit we are allowed to keep track of...
88 */
89
90 while (wnd->scan.count > LWS_WIFI_MAX_SCAN_TRACK) {
91 struct lws_dll2 *p = lws_dll2_get_tail(&wnd->scan);
92 lws_wifi_sta_t *w = lws_container_of(p, lws_wifi_sta_t, list);
93
94 lws_dll2_remove(p);
95 lws_free(w);
96 }
97
98 /*
99 * ... let's dump what's left
100 */
101
102 lws_start_foreach_dll(struct lws_dll2 *, p, lws_dll2_get_head(
103 &wnd->scan)) {
104 lws_wifi_sta_t *w = lws_container_of(p, lws_wifi_sta_t, list);
105
106 lwsl_notice("%s: %s, %02X:%02X:%02X:%02X:%02X:%02X, ch %d, rssi %d\n",
107 __func__, (const char *)&w[1], w->bssid[0],
108 w->bssid[1], w->bssid[2], w->bssid[3], w->bssid[4],
109 w->bssid[5], w->ch, rssi_averaged(w));
110
111 } lws_end_foreach_dll(p);
112
113 /*
114 * make sure we have our device's connection credentials at hand
115 */
116
117 if (!netdevs->ac_creds &&
118 lws_netdev_credentials_settings_get(netdevs))
119 return 0;
120 netdevs->refcount_creds++;
121
122 /*
123 * Let's go through each starting from the best RSSI seeing if we
124 * have credentials... if we do, pick the one we least-recently tried
125 */
126
127 lws_start_foreach_dll(struct lws_dll2 *, p1, wnd->scan.head) {
128 lws_wifi_sta_t *w = lws_container_of(p1, lws_wifi_sta_t, list);
129
130 lws_start_foreach_dll(struct lws_dll2 *, q,
131 netdevs->owner_creds.head) {
132 lws_wifi_creds_t *c = lws_container_of(q,
133 lws_wifi_creds_t,
134 list);
135
136 if (!strcmp((const char *)&w[1], c->ssid) &&
137 w->last_seen < least_recent) {
138 /*
139 * Not <= so we stick with higher RSSI when
140 * all 0
141 */
142 pc = c;
143 pw = w;
144 least_recent = w->last_seen;
145 }
146
147 } lws_end_foreach_dll(q);
148
149 } lws_end_foreach_dll(p1);
150
151
152 if (least_recent != 0xffffffff) {
153 /*
154 * We picked one to try... note what we're trying so we can
155 * record it in settings as last successful
156 */
157 lws_strncpy(wnd->current_attempt_ssid, (const char *)&pw[1],
158 sizeof(wnd->current_attempt_ssid));
159 memcpy(wnd->current_attempt_bssid, pw->bssid, LWS_ETH_ALEN);
160 wnd->inst.ops->connect(&wnd->inst, pc->ssid, pc->passphrase,
161 pw->bssid);
162 } else {
163 /*
164 * We couldn't see anyone we recognized on this scan, let's
165 * rescan in a bit
166 */
167
168 lwsl_notice("%s: nothing usable in scan, redoing in 3s\n", __func__);
169 lws_sul_schedule(cx, 0, &wnd->sul_scan, lws_netdev_wifi_scan,
170 3 * LWS_US_PER_SEC);
171 }
172
173 if (!--netdevs->refcount_creds) {
174 lws_dll2_owner_clear(&netdevs->owner_creds);
175 lwsac_free(&netdevs->ac_creds);
176 }
177
178 return 0;
179 }
180
181 /*
182 * Initially our best bet is just try to reconnect to whatever we last
183 * succeeded to connect to
184 */
185
186 int
lws_netdev_wifi_redo_last(lws_netdev_instance_wifi_t * wnd)187 lws_netdev_wifi_redo_last(lws_netdev_instance_wifi_t *wnd)
188 {
189 lws_netdevs_t *netdevs = lws_netdevs_from_ndi(&wnd->inst);
190 uint8_t buf[256], bssid[LWS_ETH_ALEN];
191 const char *ssid, *pp = "", *pb;
192 char setname[16], ssid_copy[33];
193 size_t l = sizeof(buf), al;
194 lws_wifi_creds_t *cred;
195
196 /*
197 * Let's try to retreive the last successful connect info for this
198 * netdev
199 */
200
201 lws_snprintf(setname, sizeof(setname), "netdev.last.%s", wnd->inst.name);
202 if (lws_settings_plat_get(netdevs->si, setname, buf, &l))
203 return 1;
204
205 lwsl_notice("%s: last successful %s\n", __func__, buf);
206
207 ssid = lws_json_simple_find((const char *)buf, l, "\"ssid\":", &al);
208 if (!ssid || al > 32)
209 return 1;
210
211 memcpy(ssid_copy, ssid, al);
212 ssid_copy[al + 1] = '\0';
213
214 pb = lws_json_simple_find((const char *)buf, l, "\"bssid\":", &al);
215 if (!pb)
216 return 1;
217 lws_hex_to_byte_array(pb, bssid, sizeof(bssid));
218
219 /*
220 * make sure we have our device's connection credentials at hand
221 */
222
223 if (!netdevs->ac_creds &&
224 lws_netdev_credentials_settings_get(netdevs))
225 return 1;
226 netdevs->refcount_creds++;
227
228 cred = lws_netdev_credentials_find(netdevs, ssid_copy, bssid);
229 if (cred)
230 pp = cred->passphrase;
231
232 lws_strncpy(wnd->current_attempt_ssid, ssid_copy,
233 sizeof(wnd->current_attempt_ssid));
234 memcpy(wnd->current_attempt_bssid, bssid, LWS_ETH_ALEN);
235 wnd->inst.ops->connect(&wnd->inst, ssid_copy, pp, bssid);
236
237 if (!--netdevs->refcount_creds) {
238 lws_dll2_owner_clear(&netdevs->owner_creds);
239 lwsac_free(&netdevs->ac_creds);
240 }
241
242 return 0;
243 }
244