fragattacks/src/p2p/p2p_dev_disc.c

/*
 * Wi-Fi Direct - P2P Device Discoverability procedure
 * Copyright (c) 2010, Atheros Communications
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 */

#include "includes.h"

#include "common.h"
#include "common/ieee802_11_defs.h"
#include "p2p_i.h"
#include "p2p.h"


static struct wpabuf * p2p_build_dev_disc_req(struct p2p_data *p2p,
					      struct p2p_device *go,
					      const u8 *dev_id)
{
	struct wpabuf *buf;
	u8 *len;

	buf = wpabuf_alloc(100);
	if (buf == NULL)
		return NULL;

	go->dialog_token++;
	if (go->dialog_token == 0)
		go->dialog_token = 1;
	p2p_buf_add_public_action_hdr(buf, P2P_DEV_DISC_REQ, go->dialog_token);

	len = p2p_buf_add_ie_hdr(buf);
	p2p_buf_add_device_id(buf, dev_id);
	p2p_buf_add_group_id(buf, go->info.p2p_device_addr, go->oper_ssid,
			     go->oper_ssid_len);
	p2p_buf_update_ie_hdr(buf, len);

	return buf;
}


void p2p_dev_disc_req_cb(struct p2p_data *p2p, int success)
{
	p2p_dbg(p2p, "Device Discoverability Request TX callback: success=%d",
		success);

	if (!success) {
		/*
		 * Use P2P find, if needed, to find the other device or to
		 * retry device discoverability.
		 */
		p2p_set_state(p2p, P2P_CONNECT);
		p2p_set_timeout(p2p, 0, 100000);
		return;
	}

	p2p_dbg(p2p, "GO acknowledged Device Discoverability Request - wait for response");
	/*
	 * TODO: is the remain-on-channel from Action frame TX long enough for
	 * most cases or should we try to increase its duration and/or start
	 * another remain-on-channel if needed once the previous one expires?
	 */
}


int p2p_send_dev_disc_req(struct p2p_data *p2p, struct p2p_device *dev)
{
	struct p2p_device *go;
	struct wpabuf *req;

	go = p2p_get_device(p2p, dev->member_in_go_dev);
	if (go == NULL || dev->oper_freq <= 0) {
		p2p_dbg(p2p, "Could not find peer entry for GO and frequency to send Device Discoverability Request");
		return -1;
	}

	req = p2p_build_dev_disc_req(p2p, go, dev->info.p2p_device_addr);
	if (req == NULL)
		return -1;

	p2p_dbg(p2p, "Sending Device Discoverability Request to GO " MACSTR
		" for client " MACSTR,
		MAC2STR(go->info.p2p_device_addr),
		MAC2STR(dev->info.p2p_device_addr));

	p2p->pending_client_disc_go = go;
	os_memcpy(p2p->pending_client_disc_addr, dev->info.p2p_device_addr,
		  ETH_ALEN);
	p2p->pending_action_state = P2P_PENDING_DEV_DISC_REQUEST;
	if (p2p_send_action(p2p, dev->oper_freq, go->info.p2p_device_addr,
			    p2p->cfg->dev_addr, go->info.p2p_device_addr,
			    wpabuf_head(req), wpabuf_len(req), 1000) < 0) {
		p2p_dbg(p2p, "Failed to send Action frame");
		wpabuf_free(req);
		/* TODO: how to recover from failure? */
		return -1;
	}

	wpabuf_free(req);

	return 0;
}


static struct wpabuf * p2p_build_dev_disc_resp(u8 dialog_token, u8 status)
{
	struct wpabuf *buf;
	u8 *len;

	buf = wpabuf_alloc(100);
	if (buf == NULL)
		return NULL;

	p2p_buf_add_public_action_hdr(buf, P2P_DEV_DISC_RESP, dialog_token);

	len = p2p_buf_add_ie_hdr(buf);
	p2p_buf_add_status(buf, status);
	p2p_buf_update_ie_hdr(buf, len);

	return buf;
}


void p2p_dev_disc_resp_cb(struct p2p_data *p2p, int success)
{
	p2p_dbg(p2p, "Device Discoverability Response TX callback: success=%d",
		success);
	p2p->cfg->send_action_done(p2p->cfg->cb_ctx);
}


static void p2p_send_dev_disc_resp(struct p2p_data *p2p, u8 dialog_token,
				   const u8 *addr, int freq, u8 status)
{
	struct wpabuf *resp;

	resp = p2p_build_dev_disc_resp(dialog_token, status);
	if (resp == NULL)
		return;

	p2p_dbg(p2p, "Sending Device Discoverability Response to " MACSTR
		" (status %u freq %d)",
		MAC2STR(addr), status, freq);

	p2p->pending_action_state = P2P_PENDING_DEV_DISC_RESPONSE;
	if (p2p_send_action(p2p, freq, addr, p2p->cfg->dev_addr,
			    p2p->cfg->dev_addr,
			    wpabuf_head(resp), wpabuf_len(resp), 200) < 0) {
		p2p_dbg(p2p, "Failed to send Action frame");
	}

	wpabuf_free(resp);
}


void p2p_process_dev_disc_req(struct p2p_data *p2p, const u8 *sa,
			      const u8 *data, size_t len, int rx_freq)
{
	struct p2p_message msg;
	size_t g;

	p2p_dbg(p2p, "Received Device Discoverability Request from " MACSTR
		" (freq=%d)", MAC2STR(sa), rx_freq);

	if (p2p_parse(data, len, &msg))
		return;

	if (msg.dialog_token == 0) {
		p2p_dbg(p2p, "Invalid Dialog Token 0 (must be nonzero) in Device Discoverability Request");
		p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
				       P2P_SC_FAIL_INVALID_PARAMS);
		p2p_parse_free(&msg);
		return;
	}

	if (msg.device_id == NULL) {
		p2p_dbg(p2p, "P2P Device ID attribute missing from Device Discoverability Request");
		p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
				       P2P_SC_FAIL_INVALID_PARAMS);
		p2p_parse_free(&msg);
		return;
	}

	for (g = 0; g < p2p->num_groups; g++) {
		if (p2p_group_go_discover(p2p->groups[g], msg.device_id, sa,
					  rx_freq) == 0) {
			p2p_dbg(p2p, "Scheduled GO Discoverability Request for the target device");
			/*
			 * P2P group code will use a callback to indicate TX
			 * status, so that we can reply to the request once the
			 * target client has acknowledged the request or it has
			 * timed out.
			 */
			p2p->pending_dev_disc_dialog_token = msg.dialog_token;
			os_memcpy(p2p->pending_dev_disc_addr, sa, ETH_ALEN);
			p2p->pending_dev_disc_freq = rx_freq;
			p2p_parse_free(&msg);
			return;
		}
	}

	p2p_dbg(p2p, "Requested client was not found in any group or did not support client discoverability");
	p2p_send_dev_disc_resp(p2p, msg.dialog_token, sa, rx_freq,
			       P2P_SC_FAIL_UNABLE_TO_ACCOMMODATE);
	p2p_parse_free(&msg);
}


void p2p_process_dev_disc_resp(struct p2p_data *p2p, const u8 *sa,
			       const u8 *data, size_t len)
{
	struct p2p_message msg;
	struct p2p_device *go;
	u8 status;

	p2p_dbg(p2p, "Received Device Discoverability Response from " MACSTR,
		MAC2STR(sa));

	go = p2p->pending_client_disc_go;
	if (go == NULL ||
	    os_memcmp(sa, go->info.p2p_device_addr, ETH_ALEN) != 0) {
		p2p_dbg(p2p, "Ignore unexpected Device Discoverability Response");
		return;
	}

	if (p2p_parse(data, len, &msg))
		return;

	if (msg.status == NULL) {
		p2p_parse_free(&msg);
		return;
	}

	if (msg.dialog_token != go->dialog_token) {
		p2p_dbg(p2p, "Ignore Device Discoverability Response with unexpected dialog token %u (expected %u)",
			msg.dialog_token, go->dialog_token);
		p2p_parse_free(&msg);
		return;
	}

	status = *msg.status;
	p2p_parse_free(&msg);

	p2p_dbg(p2p, "Device Discoverability Response status %u", status);

	if (p2p->go_neg_peer == NULL ||
	    os_memcmp(p2p->pending_client_disc_addr,
		      p2p->go_neg_peer->info.p2p_device_addr, ETH_ALEN) != 0 ||
	    os_memcmp(p2p->go_neg_peer->member_in_go_dev,
		      go->info.p2p_device_addr, ETH_ALEN) != 0) {
		p2p_dbg(p2p, "No pending operation with the client discoverability peer anymore");
		return;
	}

	if (status == 0) {
		/*
		 * Peer is expected to be awake for at least 100 TU; try to
		 * connect immediately.
		 */
		p2p_dbg(p2p, "Client discoverability request succeeded");
		if (p2p->state == P2P_CONNECT) {
			/*
			 * Change state to force the timeout to start in
			 * P2P_CONNECT again without going through the short
			 * Listen state.
			 */
			p2p_set_state(p2p, P2P_CONNECT_LISTEN);
			p2p->cfg->send_action_done(p2p->cfg->cb_ctx);
		}
		p2p_set_timeout(p2p, 0, 0);
	} else {
		/*
		 * Client discoverability request failed; try to connect from
		 * timeout.
		 */
		p2p_dbg(p2p, "Client discoverability request failed");
		p2p_set_timeout(p2p, 0, 500000);
	}

}


void p2p_go_disc_req_cb(struct p2p_data *p2p, int success)
{
	p2p_dbg(p2p, "GO Discoverability Request TX callback: success=%d",
		success);
	p2p->cfg->send_action_done(p2p->cfg->cb_ctx);

	if (p2p->pending_dev_disc_dialog_token == 0) {
		p2p_dbg(p2p, "No pending Device Discoverability Request");
		return;
	}

	p2p_send_dev_disc_resp(p2p, p2p->pending_dev_disc_dialog_token,
			       p2p->pending_dev_disc_addr,
			       p2p->pending_dev_disc_freq,
			       success ? P2P_SC_SUCCESS :
			       P2P_SC_FAIL_UNABLE_TO_ACCOMMODATE);

	p2p->pending_dev_disc_dialog_token = 0;
}


void p2p_process_go_disc_req(struct p2p_data *p2p, const u8 *da, const u8 *sa,
			     const u8 *data, size_t len, int rx_freq)
{
	unsigned int tu;
	struct wpabuf *ies;

	p2p_dbg(p2p, "Received GO Discoverability Request - remain awake for 100 TU");

	ies = p2p_build_probe_resp_ies(p2p);
	if (ies == NULL)
		return;

	/* Remain awake 100 TU on operating channel */
	p2p->pending_client_disc_freq = rx_freq;
	tu = 100;
	if (p2p->cfg->start_listen(p2p->cfg->cb_ctx, rx_freq, 1024 * tu / 1000,
		    ies) < 0) {
		p2p_dbg(p2p, "Failed to start listen mode for client discoverability");
	}
	wpabuf_free(ies);
}