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/*
* 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 2
#include <afb/afb-binding.h>
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
#define WAIT_FOR_REMOVE(dev) { while (0 == nfc_initiator_target_is_present(dev, NULL)) {} }
static struct afb_event 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 *to_hex_string(unsigned char *data, size_t size)
{
char *buffer = malloc((2 * size) + 1);
char *tmp = buffer;
int i;
if (buffer == NULL)
return buffer;
for (i = 0; i < size; i++) {
tmp += sprintf(tmp, "%.2x", data[i]);
}
return buffer;
}
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)
{
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));
afb_event_push(presence_event, jresp);
}
static void *nfc_loop_thread(void *ptr)
{
nfc_context *ctx = NULL;
nfc_device *dev = NULL;
nfc_init(&ctx);
dev = nfc_open(ctx, NULL);
if (dev == NULL) {
AFB_ERROR("Cannot get context for libnfc");
nfc_exit(ctx);
exit(EXIT_FAILURE);
}
if (nfc_initiator_init(dev) < 0) {
AFB_ERROR("Cannot get initiator mode from libnfc");
nfc_close(dev);
nfc_exit(ctx);
exit(EXIT_FAILURE);
}
while (1) {
nfc_target nt;
json_object *jresp;
int res = nfc_initiator_poll_target(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);
pthread_mutex_unlock(&mutex);
WAIT_FOR_REMOVE(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));
afb_event_push(presence_event, jresp);
free(current_uid);
current_uid = NULL;
pthread_mutex_unlock(&mutex);
}
nfc_close(dev);
nfc_exit(ctx);
return NULL;
}
static int init()
{
pthread_t thread_id;
presence_event = afb_daemon_make_event("presence");
return pthread_create(&thread_id, NULL, nfc_loop_thread, NULL);
}
static void subscribe(struct afb_req request)
{
const char *value = afb_req_value(request, "value");
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);
send_detect_event(current_uid);
pthread_mutex_unlock(&mutex);
return;
}
afb_req_fail(request, "failed", "Invalid event");
}
static void unsubscribe(struct afb_req 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_v2 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_v2 afbBindingV2 = {
.api = "nfc",
.specification = "NFC service API",
.verbs = binding_verbs,
.init = init,
};
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