1 /*
2  * Wi-Fi Direct - P2P Device Discoverability procedure
3  * Copyright (c) 2010, Atheros Communications
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 "common/ieee802_11_defs.h"
13 #include "p2p_i.h"
14 #include "p2p.h"
15 
16 
p2p_build_dev_disc_req(struct p2p_data * p2p,struct p2p_device * go,const u8 * dev_id)17 static struct wpabuf * p2p_build_dev_disc_req(struct p2p_data *p2p,
18 					      struct p2p_device *go,
19 					      const u8 *dev_id)
20 {
21 	struct wpabuf *buf;
22 	u8 *len;
23 
24 	buf = wpabuf_alloc(100);
25 	if (buf == NULL)
26 		return NULL;
27 
28 	go->dialog_token++;
29 	if (go->dialog_token == 0)
30 		go->dialog_token = 1;
31 	p2p_buf_add_public_action_hdr(buf, P2P_DEV_DISC_REQ, go->dialog_token);
32 
33 	len = p2p_buf_add_ie_hdr(buf);
34 	p2p_buf_add_device_id(buf, dev_id);
35 	p2p_buf_add_group_id(buf, go->info.p2p_device_addr, go->oper_ssid,
36 			     go->oper_ssid_len);
37 	p2p_buf_update_ie_hdr(buf, len);
38 
39 	return buf;
40 }
41 
42 
p2p_dev_disc_req_cb(struct p2p_data * p2p,int success)43 void p2p_dev_disc_req_cb(struct p2p_data *p2p, int success)
44 {
45 	p2p_dbg(p2p, "Device Discoverability Request TX callback: success=%d",
46 		success);
47 
48 	if (!success) {
49 		/*
50 		 * Use P2P find, if needed, to find the other device or to
51 		 * retry device discoverability.
52 		 */
53 		p2p_set_state(p2p, P2P_CONNECT);
54 		p2p_set_timeout(p2p, 0, 100000);
55 		return;
56 	}
57 
58 	p2p_dbg(p2p, "GO acknowledged Device Discoverability Request - wait for response");
59 	/*
60 	 * TODO: is the remain-on-channel from Action frame TX long enough for
61 	 * most cases or should we try to increase its duration and/or start
62 	 * another remain-on-channel if needed once the previous one expires?
63 	 */
64 }
65 
66 
p2p_send_dev_disc_req(struct p2p_data * p2p,struct p2p_device * dev)67 int p2p_send_dev_disc_req(struct p2p_data *p2p, struct p2p_device *dev)
68 {
69 	struct p2p_device *go;
70 	struct wpabuf *req;
71 	unsigned int wait_time;
72 
73 	go = p2p_get_device(p2p, dev->member_in_go_dev);
74 	if (go == NULL || dev->oper_freq <= 0) {
75 		p2p_dbg(p2p, "Could not find peer entry for GO and frequency to send Device Discoverability Request");
76 		return -1;
77 	}
78 
79 	req = p2p_build_dev_disc_req(p2p, go, dev->info.p2p_device_addr);
80 	if (req == NULL)
81 		return -1;
82 
83 	p2p_dbg(p2p, "Sending Device Discoverability Request to GO " MACSTR
84 		" for client " MACSTR,
85 		MAC2STR(go->info.p2p_device_addr),
86 		MAC2STR(dev->info.p2p_device_addr));
87 
88 	p2p->pending_client_disc_go = go;
89 	os_memcpy(p2p->pending_client_disc_addr, dev->info.p2p_device_addr,
90 		  ETH_ALEN);
91 	p2p->pending_action_state = P2P_PENDING_DEV_DISC_REQUEST;
92 	wait_time = 1000;
93 	if (p2p->cfg->max_listen && wait_time > p2p->cfg->max_listen)
94 		wait_time = p2p->cfg->max_listen;
95 	if (p2p_send_action(p2p, dev->oper_freq, go->info.p2p_device_addr,
96 			    p2p->cfg->dev_addr, go->info.p2p_device_addr,
97 			    wpabuf_head(req), wpabuf_len(req), wait_time) < 0) {
98 		p2p_dbg(p2p, "Failed to send Action frame");
99 		wpabuf_free(req);
100 		/* TODO: how to recover from failure? */
101 		return -1;
102 	}
103 
104 	wpabuf_free(req);
105 
106 	return 0;
107 }
108 
109 
p2p_build_dev_disc_resp(u8 dialog_token,u8 status)110 static struct wpabuf * p2p_build_dev_disc_resp(u8 dialog_token, u8 status)
111 {
112 	struct wpabuf *buf;
113 	u8 *len;
114 
115 	buf = wpabuf_alloc(100);
116 	if (buf == NULL)
117 		return NULL;
118 
119 	p2p_buf_add_public_action_hdr(buf, P2P_DEV_DISC_RESP, dialog_token);
120 
121 	len = p2p_buf_add_ie_hdr(buf);
122 	p2p_buf_add_status(buf, status);
123 	p2p_buf_update_ie_hdr(buf, len);
124 
125 	return buf;
126 }
127 
128 
p2p_dev_disc_resp_cb(struct p2p_data * p2p,int success)129 void p2p_dev_disc_resp_cb(struct p2p_data *p2p, int success)
130 {
131 	p2p_dbg(p2p, "Device Discoverability Response TX callback: success=%d",
132 		success);
133 	p2p->cfg->send_action_done(p2p->cfg->cb_ctx);
134 }
135 
136 
p2p_send_dev_disc_resp(struct p2p_data * p2p,u8 dialog_token,const u8 * addr,int freq,u8 status)137 static void p2p_send_dev_disc_resp(struct p2p_data *p2p, u8 dialog_token,
138 				   const u8 *addr, int freq, u8 status)
139 {
140 	struct wpabuf *resp;
141 
142 	resp = p2p_build_dev_disc_resp(dialog_token, status);
143 	if (resp == NULL)
144 		return;
145 
146 	p2p_dbg(p2p, "Sending Device Discoverability Response to " MACSTR
147 		" (status %u freq %d)",
148 		MAC2STR(addr), status, freq);
149 
150 	p2p->pending_action_state = P2P_PENDING_DEV_DISC_RESPONSE;
151 	if (p2p_send_action(p2p, freq, addr, p2p->cfg->dev_addr,
152 			    p2p->cfg->dev_addr,
153 			    wpabuf_head(resp), wpabuf_len(resp), 200) < 0) {
154 		p2p_dbg(p2p, "Failed to send Action frame");
155 	}
156 
157 	wpabuf_free(resp);
158 }
159 
160 
p2p_process_dev_disc_req(struct p2p_data * p2p,const u8 * sa,const u8 * data,size_t len,int rx_freq)161 void p2p_process_dev_disc_req(struct p2p_data *p2p, const u8 *sa,
162 			      const u8 *data, size_t len, int rx_freq)
163 {
164 	struct p2p_message msg;
165 	size_t g;
166 
167 	p2p_dbg(p2p, "Received Device Discoverability Request from " MACSTR
168 		" (freq=%d)", MAC2STR(sa), rx_freq);
169 
170 	if (p2p_parse(data, len, &msg))
171 		return;
172 
173 	if (msg.dialog_token == 0) {
174 		p2p_dbg(p2p, "Invalid Dialog Token 0 (must be nonzero) in Device Discoverability Request");
175 		p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
176 				       P2P_SC_FAIL_INVALID_PARAMS);
177 		p2p_parse_free(&msg);
178 		return;
179 	}
180 
181 	if (msg.device_id == NULL) {
182 		p2p_dbg(p2p, "P2P Device ID attribute missing from Device Discoverability Request");
183 		p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
184 				       P2P_SC_FAIL_INVALID_PARAMS);
185 		p2p_parse_free(&msg);
186 		return;
187 	}
188 
189 	for (g = 0; g < p2p->num_groups; g++) {
190 		if (p2p_group_go_discover(p2p->groups[g], msg.device_id, sa,
191 					  rx_freq) == 0) {
192 			p2p_dbg(p2p, "Scheduled GO Discoverability Request for the target device");
193 			/*
194 			 * P2P group code will use a callback to indicate TX
195 			 * status, so that we can reply to the request once the
196 			 * target client has acknowledged the request or it has
197 			 * timed out.
198 			 */
199 			p2p->pending_dev_disc_dialog_token = msg.dialog_token;
200 			os_memcpy(p2p->pending_dev_disc_addr, sa, ETH_ALEN);
201 			p2p->pending_dev_disc_freq = rx_freq;
202 			p2p_parse_free(&msg);
203 			return;
204 		}
205 	}
206 
207 	p2p_dbg(p2p, "Requested client was not found in any group or did not support client discoverability");
208 	p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
209 			       P2P_SC_FAIL_UNABLE_TO_ACCOMMODATE);
210 	p2p_parse_free(&msg);
211 }
212 
213 
p2p_process_dev_disc_resp(struct p2p_data * p2p,const u8 * sa,const u8 * data,size_t len)214 void p2p_process_dev_disc_resp(struct p2p_data *p2p, const u8 *sa,
215 			       const u8 *data, size_t len)
216 {
217 	struct p2p_message msg;
218 	struct p2p_device *go;
219 	u8 status;
220 
221 	p2p_dbg(p2p, "Received Device Discoverability Response from " MACSTR,
222 		MAC2STR(sa));
223 
224 	go = p2p->pending_client_disc_go;
225 	if (go == NULL ||
226 	    os_memcmp(sa, go->info.p2p_device_addr, ETH_ALEN) != 0) {
227 		p2p_dbg(p2p, "Ignore unexpected Device Discoverability Response");
228 		return;
229 	}
230 
231 	if (p2p_parse(data, len, &msg))
232 		return;
233 
234 	if (msg.status == NULL) {
235 		p2p_parse_free(&msg);
236 		return;
237 	}
238 
239 	if (msg.dialog_token != go->dialog_token) {
240 		p2p_dbg(p2p, "Ignore Device Discoverability Response with unexpected dialog token %u (expected %u)",
241 			msg.dialog_token, go->dialog_token);
242 		p2p_parse_free(&msg);
243 		return;
244 	}
245 
246 	status = *msg.status;
247 	p2p_parse_free(&msg);
248 
249 	p2p_dbg(p2p, "Device Discoverability Response status %u", status);
250 
251 	if (p2p->go_neg_peer == NULL ||
252 	    os_memcmp(p2p->pending_client_disc_addr,
253 		      p2p->go_neg_peer->info.p2p_device_addr, ETH_ALEN) != 0 ||
254 	    os_memcmp(p2p->go_neg_peer->member_in_go_dev,
255 		      go->info.p2p_device_addr, ETH_ALEN) != 0) {
256 		p2p_dbg(p2p, "No pending operation with the client discoverability peer anymore");
257 		return;
258 	}
259 
260 	if (status == 0) {
261 		/*
262 		 * Peer is expected to be awake for at least 100 TU; try to
263 		 * connect immediately.
264 		 */
265 		p2p_dbg(p2p, "Client discoverability request succeeded");
266 		if (p2p->state == P2P_CONNECT) {
267 			/*
268 			 * Change state to force the timeout to start in
269 			 * P2P_CONNECT again without going through the short
270 			 * Listen state.
271 			 */
272 			p2p_set_state(p2p, P2P_CONNECT_LISTEN);
273 			p2p->cfg->send_action_done(p2p->cfg->cb_ctx);
274 		}
275 		p2p_set_timeout(p2p, 0, 0);
276 	} else {
277 		/*
278 		 * Client discoverability request failed; try to connect from
279 		 * timeout.
280 		 */
281 		p2p_dbg(p2p, "Client discoverability request failed");
282 		p2p_set_timeout(p2p, 0, 500000);
283 	}
284 
285 }
286 
287 
p2p_go_disc_req_cb(struct p2p_data * p2p,int success)288 void p2p_go_disc_req_cb(struct p2p_data *p2p, int success)
289 {
290 	p2p_dbg(p2p, "GO Discoverability Request TX callback: success=%d",
291 		success);
292 	p2p->cfg->send_action_done(p2p->cfg->cb_ctx);
293 
294 	if (p2p->pending_dev_disc_dialog_token == 0) {
295 		p2p_dbg(p2p, "No pending Device Discoverability Request");
296 		return;
297 	}
298 
299 	p2p_send_dev_disc_resp(p2p, p2p->pending_dev_disc_dialog_token,
300 			       p2p->pending_dev_disc_addr,
301 			       p2p->pending_dev_disc_freq,
302 			       success ? P2P_SC_SUCCESS :
303 			       P2P_SC_FAIL_UNABLE_TO_ACCOMMODATE);
304 
305 	p2p->pending_dev_disc_dialog_token = 0;
306 }
307 
308 
p2p_process_go_disc_req(struct p2p_data * p2p,const u8 * da,const u8 * sa,const u8 * data,size_t len,int rx_freq)309 void p2p_process_go_disc_req(struct p2p_data *p2p, const u8 *da, const u8 *sa,
310 			     const u8 *data, size_t len, int rx_freq)
311 {
312 	unsigned int tu;
313 	struct wpabuf *ies;
314 
315 	p2p_dbg(p2p, "Received GO Discoverability Request - remain awake for 100 TU");
316 
317 	ies = p2p_build_probe_resp_ies(p2p, NULL, 0);
318 	if (ies == NULL)
319 		return;
320 
321 	/* Remain awake 100 TU on operating channel */
322 	p2p->pending_client_disc_freq = rx_freq;
323 	tu = 100;
324 	if (p2p->cfg->start_listen(p2p->cfg->cb_ctx, rx_freq, 1024 * tu / 1000,
325 		    ies) < 0) {
326 		p2p_dbg(p2p, "Failed to start listen mode for client discoverability");
327 	}
328 	wpabuf_free(ies);
329 }
330