binding: nfc: new initial binding

Slight rewrite to use libnfc initially for getting tag uid's for
user settings.

Bug-AGL: SPEC-1554
Change-Id: I7b8c30102b82e86a92c89909bcbfba9ab7164c1f
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>

2 files changed, 235 insertions, 0 deletions

diff --git a/binding/CMakeLists.txt b/binding/CMakeLists.txt
new file mode 100644
index 0000000..512cede
--- /dev/null
+++ b/binding/CMakeLists.txt
@@ -0,0 +1,35 @@
+###########################################################################
+# Copyright 2015, 2016, 2017 IoT.bzh
+#
+# author: Fulup Ar Foll <fulup@iot.bzh>
+# contrib: Romain Forlot <romain.forlot@iot.bzh>
+#
+# 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.
+###########################################################################
+
+# Add target to project dependency list
+PROJECT_TARGET_ADD(afm-nfc-binding)
+
+	# Define project Targets
+	add_library(afm-nfc-binding MODULE afm-nfc-binding.c)
+
+	# Binder exposes a unique public entry point
+	SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+		PREFIX "lib"
+		LABELS "BINDING"
+		LINK_FLAGS ${BINDINGS_LINK_FLAG}
+		OUTPUT_NAME ${TARGET_NAME}
+	)
+
+	# Library dependencies (include updates automatically)
+	TARGET_LINK_LIBRARIES(${TARGET_NAME} ${link_libraries})
diff --git a/binding/afm-nfc-binding.c b/binding/afm-nfc-binding.c
new file mode 100644
index 0000000..c92c36c
--- /dev/null
+++ b/binding/afm-nfc-binding.c
@@ -0,0 +1,200 @@
+/*
+ * 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,
+};