P2P NFC: Build connection handover messages

"NFC_GET_HANDOVER_{REQ,SEL} NDEF P2P-CR" can now be used to build P2P
alternative carrier record for NFC connection handover request/select
messages.

Static connection handover case can be enabled by configuring the DH
parameters (either with wps_nfc_* configuration parameters or with
WPS_NFC_TOKEN command at run time. The NFC Tag contents can be generated
with "NFC_GET_HANDOVER_SEL NDEF P2P-CR-TAG" after having configured
Listen channel (p2p_listen_reg_class/p2p_listen_channel).

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>

src/p2p/p2p.c

@@ -4370,3 +4370,55 @@ void p2p_err(struct p2p_data *p2p, const char *fmt, ...)
 	va_end(ap);
 	p2p->cfg->debug_print(p2p->cfg->cb_ctx, MSG_ERROR, buf);
 }
+
+
+#ifdef CONFIG_WPS_NFC
+
+static struct wpabuf * p2p_build_nfc_handover(struct p2p_data *p2p)
+{
+	struct wpabuf *buf;
+	u8 op_class, channel;
+	enum p2p_role_indication role = P2P_DEVICE_NOT_IN_GROUP;
+
+	buf = wpabuf_alloc(1000);
+	if (buf == NULL)
+		return NULL;
+
+	op_class = p2p->cfg->reg_class;
+	channel = p2p->cfg->channel;
+
+	p2p_buf_add_capability(buf, p2p->dev_capab &
+			       ~P2P_DEV_CAPAB_CLIENT_DISCOVERABILITY, 0);
+	p2p_buf_add_device_info(buf, p2p, NULL);
+
+	if (p2p->num_groups > 0) {
+		role = P2P_GO_IN_A_GROUP;
+		p2p_freq_to_channel(p2p_group_get_freq(p2p->groups[0]),
+				    &op_class, &channel);
+	}
+
+	p2p_buf_add_oob_go_neg_channel(buf, p2p->cfg->country, op_class,
+				       channel, role);
+
+	if (p2p->num_groups > 0) {
+		/* Limit number of clients to avoid very long message */
+		p2p_buf_add_group_info(p2p->groups[0], buf, 5);
+		p2p_group_buf_add_id(p2p->groups[0], buf);
+	}
+
+	return buf;
+}
+
+
+struct wpabuf * p2p_build_nfc_handover_req(struct p2p_data *p2p)
+{
+	return p2p_build_nfc_handover(p2p);
+}
+
+
+struct wpabuf * p2p_build_nfc_handover_sel(struct p2p_data *p2p)
+{
+	return p2p_build_nfc_handover(p2p);
+}
+
+#endif /* CONFIG_WPS_NFC */

src/p2p/p2p.h

@@ -1897,4 +1897,7 @@ int p2p_set_disc_int(struct p2p_data *p2p, int min_disc_int, int max_disc_int,
  */
 const char * p2p_get_state_txt(struct p2p_data *p2p);
 
+struct wpabuf * p2p_build_nfc_handover_req(struct p2p_data *p2p);
+struct wpabuf * p2p_build_nfc_handover_sel(struct p2p_data *p2p);
+
 #endif /* P2P_H */

src/p2p/p2p_group.c

@@ -419,6 +419,13 @@ void p2p_buf_add_group_info(struct p2p_group *group, struct wpabuf *buf,
 }
 
 
+void p2p_group_buf_add_id(struct p2p_group *group, struct wpabuf *buf)
+{
+	p2p_buf_add_group_id(buf, group->p2p->cfg->dev_addr, group->cfg->ssid,
+			     group->cfg->ssid_len);
+}
+
+
 static struct wpabuf * p2p_group_build_probe_resp_ie(struct p2p_group *group)
 {
 	struct wpabuf *p2p_subelems, *ie;

src/p2p/p2p_i.h

@@ -613,6 +613,7 @@ void p2p_group_force_beacon_update_ies(struct p2p_group *group);
 struct wpabuf * p2p_group_get_wfd_ie(struct p2p_group *g);
 void p2p_buf_add_group_info(struct p2p_group *group, struct wpabuf *buf,
 			    int max_clients);
+void p2p_group_buf_add_id(struct p2p_group *group, struct wpabuf *buf);
 int p2p_group_get_freq(struct p2p_group *group);
 
 

wpa_supplicant/ctrl_iface.c

@@ -928,6 +928,30 @@ static int wpas_ctrl_nfc_get_handover_req_wps(struct wpa_supplicant *wpa_s,
 }
 
 
+static int wpas_ctrl_nfc_get_handover_req_p2p(struct wpa_supplicant *wpa_s,
+					      char *reply, size_t max_len,
+					      int ndef)
+{
+	struct wpabuf *buf;
+	int res;
+
+	buf = wpas_p2p_nfc_handover_req(wpa_s, ndef);
+	if (buf == NULL) {
+		wpa_printf(MSG_DEBUG, "P2P: Could not generate NFC handover request");
+		return -1;
+	}
+
+	res = wpa_snprintf_hex_uppercase(reply, max_len, wpabuf_head(buf),
+					 wpabuf_len(buf));
+	reply[res++] = '\n';
+	reply[res] = '\0';
+
+	wpabuf_free(buf);
+
+	return res;
+}
+
+
 static int wpas_ctrl_nfc_get_handover_req(struct wpa_supplicant *wpa_s,
 					  char *cmd, char *reply,
 					  size_t max_len)
@@ -954,6 +978,11 @@ static int wpas_ctrl_nfc_get_handover_req(struct wpa_supplicant *wpa_s,
 			wpa_s, reply, max_len, ndef);
 	}
 
+	if (os_strcmp(pos, "P2P-CR") == 0) {
+		return wpas_ctrl_nfc_get_handover_req_p2p(
+			wpa_s, reply, max_len, ndef);
+	}
+
 	return -1;
 }
 
@@ -980,6 +1009,28 @@ static int wpas_ctrl_nfc_get_handover_sel_wps(struct wpa_supplicant *wpa_s,
 }
 
 
+static int wpas_ctrl_nfc_get_handover_sel_p2p(struct wpa_supplicant *wpa_s,
+					      char *reply, size_t max_len,
+					      int ndef, int tag)
+{
+	struct wpabuf *buf;
+	int res;
+
+	buf = wpas_p2p_nfc_handover_sel(wpa_s, ndef, tag);
+	if (buf == NULL)
+		return -1;
+
+	res = wpa_snprintf_hex_uppercase(reply, max_len, wpabuf_head(buf),
+					 wpabuf_len(buf));
+	reply[res++] = '\n';
+	reply[res] = '\0';
+
+	wpabuf_free(buf);
+
+	return res;
+}
+
+
 static int wpas_ctrl_nfc_get_handover_sel(struct wpa_supplicant *wpa_s,
 					  char *cmd, char *reply,
 					  size_t max_len)
@@ -1003,11 +1054,23 @@ static int wpas_ctrl_nfc_get_handover_sel(struct wpa_supplicant *wpa_s,
 	if (pos2)
 		*pos2++ = '\0';
 	if (os_strcmp(pos, "WPS") == 0 || os_strcmp(pos, "WPS-CR") == 0) {
+		if (!ndef)
+			return -1;
 		return wpas_ctrl_nfc_get_handover_sel_wps(
 			wpa_s, reply, max_len, ndef,
 			os_strcmp(pos, "WPS-CR") == 0, pos2);
 	}
 
+	if (os_strcmp(pos, "P2P-CR") == 0) {
+		return wpas_ctrl_nfc_get_handover_sel_p2p(
+			wpa_s, reply, max_len, ndef, 0);
+	}
+
+	if (os_strcmp(pos, "P2P-CR-TAG") == 0) {
+		return wpas_ctrl_nfc_get_handover_sel_p2p(
+			wpa_s, reply, max_len, ndef, 1);
+	}
+
 	return -1;
 }
 

wpa_supplicant/p2p_supplicant.c

@@ -6923,3 +6923,106 @@ int wpas_p2p_4way_hs_failed(struct wpa_supplicant *wpa_s)
 	wpa_s->p2p_last_4way_hs_fail = ssid;
 	return 0;
 }
+
+
+#ifdef CONFIG_WPS_NFC
+
+static struct wpabuf * wpas_p2p_nfc_handover(int ndef, struct wpabuf *wsc,
+					     struct wpabuf *p2p)
+{
+	struct wpabuf *ret;
+
+	if (wsc == NULL) {
+		wpabuf_free(p2p);
+		return NULL;
+	}
+
+	if (p2p == NULL) {
+		wpabuf_free(wsc);
+		wpa_printf(MSG_DEBUG, "P2P: No p2p buffer for handover");
+		return NULL;
+	}
+
+	ret = wpabuf_alloc(2 + wpabuf_len(wsc) + 2 + wpabuf_len(p2p));
+	if (ret == NULL) {
+		wpabuf_free(wsc);
+		wpabuf_free(p2p);
+		return NULL;
+	}
+
+	wpabuf_put_be16(ret, wpabuf_len(wsc));
+	wpabuf_put_buf(ret, wsc);
+	wpabuf_put_be16(ret, wpabuf_len(p2p));
+	wpabuf_put_buf(ret, p2p);
+
+	wpabuf_free(wsc);
+	wpabuf_free(p2p);
+	wpa_hexdump_buf(MSG_DEBUG,
+			"P2P: Generated NFC connection handover message", ret);
+
+	if (ndef && ret) {
+		struct wpabuf *tmp;
+		tmp = ndef_build_p2p(ret);
+		wpabuf_free(ret);
+		if (tmp == NULL) {
+			wpa_printf(MSG_DEBUG, "P2P: Failed to NDEF encapsulate handover request");
+			return NULL;
+		}
+		ret = tmp;
+	}
+
+	return ret;
+}
+
+
+struct wpabuf * wpas_p2p_nfc_handover_req(struct wpa_supplicant *wpa_s,
+					  int ndef)
+{
+	struct wpabuf *wsc, *p2p;
+
+	if (wpa_s->global->p2p_disabled || wpa_s->global->p2p == NULL) {
+		wpa_printf(MSG_DEBUG, "P2P: P2P disabled - cannot build handover request");
+		return NULL;
+	}
+
+	if (wpa_s->conf->wps_nfc_dh_pubkey == NULL &&
+	    wps_nfc_gen_dh(&wpa_s->conf->wps_nfc_dh_pubkey,
+			   &wpa_s->conf->wps_nfc_dh_privkey) < 0) {
+		wpa_dbg(wpa_s, MSG_DEBUG, "P2P: No DH key available for handover request");
+		return NULL;
+	}
+
+	wsc = wps_build_nfc_handover_req_p2p(wpa_s->parent->wps,
+					     wpa_s->conf->wps_nfc_dh_pubkey);
+	p2p = p2p_build_nfc_handover_req(wpa_s->global->p2p);
+
+	return wpas_p2p_nfc_handover(ndef, wsc, p2p);
+}
+
+
+struct wpabuf * wpas_p2p_nfc_handover_sel(struct wpa_supplicant *wpa_s,
+					  int ndef, int tag)
+{
+	struct wpabuf *wsc, *p2p;
+
+	if (wpa_s->global->p2p_disabled || wpa_s->global->p2p == NULL)
+		return NULL;
+
+	if (!tag && wpa_s->conf->wps_nfc_dh_pubkey == NULL &&
+	    wps_nfc_gen_dh(&wpa_s->conf->wps_nfc_dh_pubkey,
+			   &wpa_s->conf->wps_nfc_dh_privkey) < 0)
+		return NULL;
+
+	wsc = wps_build_nfc_handover_sel_p2p(wpa_s->parent->wps,
+					     tag ?
+					     wpa_s->conf->wps_nfc_dev_pw_id :
+					     DEV_PW_NFC_CONNECTION_HANDOVER,
+					     wpa_s->conf->wps_nfc_dh_pubkey,
+					     tag ? wpa_s->conf->wps_nfc_dev_pw :
+					     NULL);
+	p2p = p2p_build_nfc_handover_sel(wpa_s->global->p2p);
+
+	return wpas_p2p_nfc_handover(ndef, wsc, p2p);
+}
+
+#endif /* CONFIG_WPS_NFC */

wpa_supplicant/p2p_supplicant.h

@@ -148,6 +148,10 @@ void wpas_p2p_new_psk_cb(struct wpa_supplicant *wpa_s, const u8 *mac_addr,
 			 const u8 *psk, size_t psk_len);
 void wpas_p2p_remove_client(struct wpa_supplicant *wpa_s, const u8 *peer,
 			    int iface_addr);
+struct wpabuf * wpas_p2p_nfc_handover_req(struct wpa_supplicant *wpa_s,
+					  int ndef);
+struct wpabuf * wpas_p2p_nfc_handover_sel(struct wpa_supplicant *wpa_s,
+					  int ndef, int tag);
 
 #ifdef CONFIG_P2P
 int wpas_p2p_4way_hs_failed(struct wpa_supplicant *wpa_s);