aboutsummaryrefslogtreecommitdiffstats
path: root/binding/afm-nfc-binding.c
blob: 35fd00e0390c2f12a158a52a1bd7988d31733f80 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/*
 * Copyright (C) 2018 Konsulko Group
 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * TODO: add support for NFC p2p transactions
 */

#define _GNU_SOURCE
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <pthread.h>
#include <glib.h>
#include <glib-object.h>
#include <json-c/json.h>
#include <nfc/nfc.h>
#include <nfc/nfc-types.h>

#define AFB_BINDING_VERSION 3
#include <afb/afb-binding.h>

#include "afm-nfc-common.h"

#define WAIT_FOR_REMOVE(dev) { while (0 == nfc_initiator_target_is_present(dev, NULL)) {} }

static afb_event_t presence_event;
static char *current_uid = NULL;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

static const nfc_modulation modulations[] = {
	{ .nmt = NMT_ISO14443A, .nbr = NBR_106 },
};

static char *get_tag_uid(nfc_target *nt)
{
	if (nt->nm.nmt == NMT_ISO14443A)
		return to_hex_string((unsigned char *) &nt->nti.nai.abtUid, nt->nti.nai.szUidLen);

	return NULL;
}

static void send_detect_event(char *current_id, nfc_binding_data *data)
{
	json_object *jresp;

	if (current_id == NULL)
		return;

	jresp = json_object_new_object();

	json_object_object_add(jresp, "status", json_object_new_string("detected"));
	json_object_object_add(jresp, "uid", json_object_new_string(current_uid));

	if (data->jresp) {
		json_object_put(data->jresp);
		data->jresp = NULL;
	}

	json_object_get(jresp);
	data->jresp = jresp;

	afb_event_push(presence_event, jresp);
}

static void *nfc_loop_thread(void *ptr)
{
	nfc_binding_data *data = ptr;

	while (1) {
		nfc_target nt;
		json_object *jresp;
		int res = nfc_initiator_poll_target(data->dev, modulations, ARRAY_SIZE(modulations), 0xff, 2, &nt);

		if (res < 0)
			break;

		pthread_mutex_lock(&mutex);

		current_uid = get_tag_uid(&nt);
		send_detect_event(current_uid, data);

		pthread_mutex_unlock(&mutex);

		WAIT_FOR_REMOVE(data->dev);

		pthread_mutex_lock(&mutex);

		jresp = json_object_new_object();
		json_object_object_add(jresp, "status", json_object_new_string("removed"));
		json_object_object_add(jresp, "uid", json_object_new_string(current_uid));

		if (data->jresp) {
			json_object_put(data->jresp);
			data->jresp = NULL;
		}

		afb_event_push(presence_event, jresp);

		pthread_mutex_unlock(&mutex);
	}

	nfc_close(data->dev);
	nfc_exit(data->ctx);
	free(data);

	return NULL;
}


static nfc_binding_data *get_libnfc_instance()
{
	nfc_context *ctx = NULL;
	nfc_device *dev = NULL;
	nfc_binding_data *data;

	nfc_init(&ctx);

	dev = nfc_open(ctx, NULL);

	if (dev == NULL) {
		AFB_ERROR("Cannot get context for libnfc");
		nfc_exit(ctx);
		return NULL;
	}

	if (nfc_initiator_init(dev) < 0) {
		AFB_ERROR("Cannot get initiator mode from libnfc");
		nfc_close(dev);
		nfc_exit(ctx);
		return NULL;
	}

	data = malloc(sizeof(nfc_binding_data));

	if (data) {
		data->ctx = ctx;
		data->dev = dev;
	}

	return data;
}

static int init(afb_api_t api)
{
	pthread_t thread_id;
	nfc_binding_data *data = get_libnfc_instance();

	presence_event = afb_daemon_make_event("presence");

	if (data) {
		afb_api_set_userdata(api, data);

		return pthread_create(&thread_id, NULL, nfc_loop_thread, data);
	}

	return -ENODEV;
}

static void subscribe(afb_req_t request)
{
	const char *value = afb_req_value(request, "value");
	afb_api_t api = afb_req_get_api(request);
	nfc_binding_data *data = afb_api_get_userdata(api);

	if (value && !strcasecmp(value, "presence")) {
		afb_req_subscribe(request, presence_event);
		afb_req_success(request, NULL, NULL);

		// send initial tag if exists
		pthread_mutex_lock(&mutex);
		if (data && data->jresp) {
			json_object_get(data->jresp);
			afb_event_push(presence_event, data->jresp);
		}
		pthread_mutex_unlock(&mutex);

		return;
	}

	afb_req_fail(request, "failed", "Invalid event");
}

static void unsubscribe(afb_req_t request)
{
	const char *value = afb_req_value(request, "value");

	if (value && !strcasecmp(value, "presence")) {
		afb_req_unsubscribe(request, presence_event);
		afb_req_success(request, NULL, NULL);
		return;
	}

	afb_req_fail(request, "failed", "Invalid event");
}

static const struct afb_verb_v3 binding_verbs[] = {
	{ .verb = "subscribe",   .callback = subscribe,    .info = "Subscribe to NFC events" },
	{ .verb = "unsubscribe", .callback = unsubscribe,  .info = "Unsubscribe to NFC events" },
	{ }
};

/*
 * binder API description
 */
const struct afb_binding_v3 afbBindingV3 = {
	.api		= "nfc",
	.specification	= "NFC service API",
	.verbs		= binding_verbs,
	.init		= init,
};