Reworked open_can_dev function and can_handler struct

Change-Id: I787730cf2ef8dfd7b1db7f9add51700401e013c1
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

1 files changed, 560 insertions, 0 deletions

diff --git a/ll-can-binding.c b/ll-can-binding.c
new file mode 100644
index 0000000..bc52d17
--- /dev/null
+++ b/ll-can-binding.c
@@ -0,0 +1,560 @@
+/*
+ * Copyright (C) 2015, 2016 "IoT.bzh"
+ * Author "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.
+ */
+#define _GNU_SOURCE
+
+#include <string.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <sys/time.h>
+#include <linux/can.h>
+#include <linux/can/raw.h>
+#include <math.h>
+#include <fcntl.h>
+#include <systemd/sd-event.h>
+#include <errno.h>
+
+#include <json-c/json.h>
+#include <openxc.pb.h>
+
+#include <afb/afb-binding.h>
+#include <afb/afb-service-itf.h>
+
+#include "canLL-binding.h"
+
+/*************************************************************************/
+/*************************************************************************/
+/**									**/
+/**									**/
+/**	   SECTION: UTILITY FUNCTIONS					**/
+/**									**/
+/**									**/
+/*************************************************************************/
+/*************************************************************************/
+
+/*
+ * Retry a function 3 times
+ *
+ * param int function(): function that return an int wihtout any parameter
+ *
+ * return : 0 if ok, -1 if failed
+ *
+ */
+static int retry( int(*func)());
+static int retry( int(*func)())
+{
+	int i;
+
+	for (i=0;i<4;i++)
+	{
+		if ( (*func)() >= 0)
+		{
+			return 0;
+		}
+		usleep(100000);
+	}
+	return -1;
+}
+
+/*
+ * Browse chained list and return the one with specified id
+ *
+ * param uint32_t id : can arbitration identifier
+ *
+ * return can_event
+ */
+static can_event *get_event_of_id(uint32_t id)
+{
+	can_event *current;
+
+	/* create and return if lists not exists */
+	if (!can_events_list)
+	{
+		can_events_list = (can_event*)calloc(1, sizeof(can_event));
+		can_events_list->id = id;
+		return can_events_list;
+	}
+
+	/* search for id */
+	current = can_events_list;
+	while(current)
+	{
+		if (current->id == id)
+			return current;
+		if (!current->next)
+		{
+			current->next = (can_event*)calloc(1, sizeof(can_event));
+			current->next->id = id;
+			return current->next;
+		}
+		current = current->next;
+	}
+
+	return NULL;
+}
+
+/*
+ * Take an id and return it into a char array
+ */
+char* create_name(uint32_t id)
+{
+	char name[32];
+	size_t nchar;
+
+	nchar = (size_t)sprintf(name, "can_%u", id);
+	if (nchar > 0)
+	{
+		char *result = (char*)malloc(nchar + 1);
+		memcpy(result, name, nchar);
+		result[nchar] = 0;
+		return result;
+	}
+
+	return NULL;
+}
+
+/*************************************************************************/
+/*************************************************************************/
+/**									**/
+/**									**/
+/**	   SECTION: HANDLE CAN DEVICE					**/
+/**									**/
+/**									**/
+/*************************************************************************/
+/*************************************************************************/
+/*
+ * open the can socket
+ */
+static int open_can_dev()
+{
+	const int canfd_on = 1;
+	struct ifreq ifr;
+	struct timeval timeout = {1,0};
+
+	DEBUG(interface, "open_can_dev: CAN Handler socket : %d", can_handler.socket);
+	if (can_handler.socket >= 0)
+		close(can_handler.socket);
+
+	can_handler.socket = socket(PF_CAN, SOCK_RAW, CAN_RAW);
+	if (can_handler.socket < 0)
+	{
+		ERROR(interface, "open_can_dev: socket could not be created");
+	}
+	else
+	{
+		/* Set timeout for read */
+		setsockopt(can_handler.socket, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+		/* try to switch the socket into CAN_FD mode */
+		if (setsockopt(can_handler.socket, SOL_CAN_RAW, CAN_RAW_FD_FRAMES, &canfd_on, sizeof(canfd_on)) < 0)
+		{
+			NOTICE(interface, "open_can_dev: Can not switch into CAN Extended frame format.");
+			can_handler.is_fdmode_on = false;
+		} else {
+			can_handler.is_fdmode_on = true;
+		}
+
+		/* Attempts to open a socket to CAN bus */
+		strcpy(ifr.ifr_name, can_handler.device);
+		if(ioctl(can_handler.socket, SIOCGIFINDEX, &ifr) < 0)
+			ERROR(interface, "open_can_dev: ioctl failed");
+		else
+		{
+			can_handler.txAddress.can_family = AF_CAN;
+			can_handler.txAddress.can_ifindex = ifr.ifr_ifindex;
+
+			/* And bind it to txAddress */
+			if (bind(can_handler.socket, (struct sockaddr *)&can_handler.txAddress, sizeof(can_handler.txAddress)) < 0)
+			{
+				ERROR(interface, "open_can_dev: bind failed");
+			}
+			else
+			{
+				fcntl(can_handler.socket, F_SETFL, O_NONBLOCK);
+				return 0;
+			}
+		}
+		close(can_handler.socket);
+		can_handler.socket = -1;
+	}
+	return -1;
+}
+
+/*
+ * TODO : test that socket is really opened
+ */
+static int write_can()
+{
+	ssize_t nbytes;
+	int rc;
+
+	rc = can_handler.socket;
+	if (rc >= 0)
+	{
+/*
+ * TODO change old hvac write can frame to generic on_event
+ */
+		nbytes = sendto(can_handler.socket, &canfd_frame, sizeof(struct canfd_frame), 0,
+			    (struct sockaddr*)&can_handler.txAddress, sizeof(can_handler.txAddress));
+		if (nbytes < 0)
+		{
+			ERROR(interface, "write_can: Sending CAN frame failed.");
+		}
+	}
+	else
+	{
+		ERROR(interface, "write_can: socket not initialized. Attempt to reopen can device socket.");
+		retry(open_can_dev);
+	}
+	return rc;
+}
+
+/*
+ * Read on CAN bus and return how much bytes has been read.
+ * TODO : test that socket is really opened
+ */
+static int read_can(openxc_CanMessage *can_message)
+{
+	ssize_t nbytes;
+	int maxdlen;
+
+	nbytes = read(can_handler.socket, &canfd_frame, CANFD_MTU);
+
+	if (nbytes == CANFD_MTU)
+	{
+		DEBUG(interface, "read_can: Got an CAN FD frame with length %d", canfd_frame.len);
+	}
+	else if (nbytes == CAN_MTU)
+	{
+		DEBUG(interface, "read_can: Got a legacy CAN frame with length %d", canfd_frame.len);
+	}
+	else
+	{
+	 	if (errno == ENETDOWN)
+			ERROR(interface, "read_can: %s interface down", can_handler.device);
+		ERROR(interface, "read_can: Error reading CAN bus");
+		return -1;
+	}
+
+	/* CAN frame integrity check */
+	if ((size_t)nbytes == CAN_MTU)
+		maxdlen = CAN_MAX_DLEN;
+	else if ((size_t)nbytes == CANFD_MTU)
+		maxdlen = CANFD_MAX_DLEN;
+	else
+	{
+		ERROR(interface, "read_can: CAN frame incomplete");
+		return -2;
+	}
+
+	parse_can_frame(can_message, &canfd_frame, maxdlen);
+}
+
+/*
+ * Parse the CAN frame data payload as a CAN packet
+ * TODO: parse as an OpenXC Can Message. Don't translate as ASCII and put bytes
+ * directly into openxc_CanMessage
+ */
+static void parse_can_frame(openxc_CanMessage *can_message, struct canfd_frame *canfd_frame, int maxdlen)
+{
+	int i,offset;
+	int len = (canfd_frame->len > maxdlen) ? maxdlen : canfd_frame->len;
+	char buf[CL_CFSZ];
+
+	if (canfd_frame->can_id & CAN_ERR_FLAG)
+	{
+		can_message->has_id = true;
+		can_message->id = canfd_frame->can_id;
+		put_eff_id(buf, canfd_frame->can_id & (CAN_ERR_MASK|CAN_ERR_FLAG));
+		buf[8] = '#';
+		offset = 9;
+	} else if (canfd_frame->can_id & CAN_EFF_FLAG)
+	{
+		put_eff_id(buf, canfd_frame->can_id & CAN_EFF_MASK);
+		buf[8] = '#';
+		offset = 9;
+	} else {
+		put_sff_id(buf, canfd_frame->can_id & CAN_SFF_MASK);
+		buf[3] = '#';
+		offset = 4;
+	}
+
+	/* standard CAN frames may have RTR enabled. There are no ERR frames with RTR */
+	if (maxdlen == CAN_MAX_DLEN && canfd_frame->can_id & CAN_RTR_FLAG)
+	{
+		buf[offset++] = 'R';
+		/* print a given CAN 2.0B DLC if it's not zero */
+		if (canfd_frame->len && canfd_frame->len <= CAN_MAX_DLC)
+			buf[offset++] = hex_asc_upper[canfd_frame->len & 0xF];
+
+		buf[offset] = 0;
+		return;
+	}
+
+	if (maxdlen == CANFD_MAX_DLEN)
+	{
+		/* add CAN FD specific escape char and flags */
+		buf[offset++] = '#';
+		buf[offset++] = hex_asc_upper[canfd_frame->flags & 0xF];
+	}
+
+	for (i = 0; i < len; i++)
+	{
+		put_hex_byte(buf + offset, canfd_frame->data[i]);
+		offset += 2;
+	}
+
+	buf[offset] = 0;
+	return;
+}
+
+/*************************************************************************/
+/*************************************************************************/
+/**									**/
+/**									**/
+/**       SECTION: MANAGING EVENTS					**/
+/**									**/
+/**									**/
+/*************************************************************************/
+/*************************************************************************/
+/*
+ * called on an event on the CAN bus
+ */
+static int on_event(sd_event_source *s, int fd, uint32_t revents, void *userdata)
+{
+	openxc_CanMessage can_message;
+
+	/* read available data */
+	if ((revents & EPOLLIN) != 0)
+	{
+		read_can(&can_message);
+		send_event();
+	}
+
+	/* check if error or hangup */
+	if ((revents & (EPOLLERR|EPOLLRDHUP|EPOLLHUP)) != 0)
+	{
+		sd_event_source_unref(s);
+		close(fd);
+		connect_to_event_loop();
+	}
+
+	return 0;
+}
+
+/*
+ * get or create an event handler for the type
+ * TODO: implement function and handle retrieve or create an event as needed
+ */
+static event *get_event(uint32_t id, enum type type)
+{
+	event *event;
+	can_event *list;
+
+	/* find the can list by id */
+	list = get_event_of_id(id);
+
+	/* make the new event */
+	event = (can_event*)calloc(1, sizeof(can_event));
+	event->next = event;
+	list->events = event;
+	event->name = create_name(id);
+	event->afb_event = afb_daemon_make_event(interface->daemon, event->name);
+
+	return event;
+}
+
+/*
+ * Send an event
+ */
+static void send_event()
+{
+	can_event *current;
+
+	/* search for id */
+	current = can_events_list;
+	while(current)
+	{
+		afb_event_push(current->afb_event, object);
+		current = current->next;
+	}
+}
+
+/*
+ * Get the event loop running.
+ * Will trigger on_event function on EPOLLIN event on socket
+ *
+ * Return 0 or positive value on success. Else negative value for failure.
+ */
+static int connect_to_event_loop()
+{
+	sd_event *event_loop;
+	sd_event_source *source;
+	int rc;
+
+	if (can_handler.socket < 0)
+	{
+		return can_handler.socket;
+	}
+
+	event_loop = afb_daemon_get_event_loop(interface->daemon);
+	rc = sd_event_add_io(event_loop, &source, can_handler.socket, EPOLLIN, on_event, NULL);
+	if (rc < 0)
+	{
+		close(can_handler.socket);
+		ERROR(interface, "Can't connect CAN bus %s to the event loop", can_handler.device);
+	} else
+	{
+		NOTICE(interface, "Connected CAN bus %s to the event loop", can_handler.device);
+	}
+
+	return rc;
+}
+
+
+/*************************************************************************/
+/*************************************************************************/
+/**									**/
+/**									**/
+/**	   SECTION: BINDING VERBS IMPLEMENTATION			**/
+/**									**/
+/**									**/
+/*************************************************************************/
+/*************************************************************************/
+/*
+ * Returns the type corresponding to the given name
+ */
+static enum type type_of_name(const char *name)
+{
+	enum type result;
+	if (name == NULL)
+		return type_DEFAULT;
+	for (result = 0 ; (size_t)result < type_size; result++)
+		if (strcmp(type_NAMES[result], name) == 0)
+			return result;
+	return type_INVALID;
+}
+
+/*
+ * extract a valid type from the request
+ */
+static int get_type_for_req(struct afb_req req, enum type *type)
+{
+	if ((*type = type_of_name(afb_req_value(req, "type"))) != type_INVALID)
+		return 1;
+	afb_req_fail(req, "unknown-type", NULL);
+	return 0;
+}
+
+/*
+ * subscribe to notification of new CAN messages
+ *
+ * parameters of the subscription are:
+ *
+ *    TODO type: string:  choose between CAN and OBDII messages formats.
+ *
+ * returns an object with 2 fields:
+ *
+ *    name:   string:  the name of the event without its prefix
+ *    id:     integer: a numeric identifier of the event to be used for unsubscribing
+ */
+static void subscribe(struct afb_req req)
+{
+	enum type type;
+	const char *period;
+	event *event;
+	uint32_t id;
+	struct json_object *json;
+
+	if (get_type_for_req(req, &type))
+	{
+		id = (uint32_t)atoi(afb_req_value(req, "id"));
+		event = get_event(id, type);
+		if (event == NULL)
+			afb_req_fail(req, "out-of-memory", NULL);
+		else if (afb_req_subscribe(req, event->afb_event) != 0)
+			afb_req_fail_f(req, "failed", "afb_req_subscribe returned an error: %m");
+		else
+		{
+			/* TODO : build json openXC message to send. I guess */
+			json = json_object_new_object();
+			json_object_object_add(json, "name", json_object_new_string(event->name));
+			afb_req_success(req, json, NULL);
+		}
+	}
+}
+
+/*
+ * unsubscribe a previous subscription
+ *
+ * parameters of the unsubscription are:
+ *
+ *    id:   integer: the numeric identifier of the event as returned when subscribing
+ */
+static void unsubscribe(struct afb_req req)
+{
+	const char *id;
+	event *event;
+
+	id = afb_req_value(req, "id");
+	if (id == NULL)
+		afb_req_fail(req, "missing-id", NULL);
+	else
+	{
+		event = get_event_of_id(atoi(id));
+		if (event == NULL)
+			afb_req_fail(req, "bad-id", NULL);
+		else
+		{
+			afb_req_unsubscribe(req, event->event);
+			afb_req_success(req, NULL, NULL);
+		}
+	}
+}
+
+// TODO: Have to change session management flag to AFB_SESSION_CHECK to use token auth
+static const struct afb_verb_desc_v1 verbs[]=
+{
+  { .name= "subscribe",    .session= AFB_SESSION_NONE, .callback= subscribe,    .info= "subscribe to notification of CAN bus messages." },
+  { .name= "unsubscribe",  .session= AFB_SESSION_NONE, .callback= unsubscribe,  .info= "unsubscribe a previous subscription." },
+	{NULL}
+};
+
+static const struct afb_binding binding_desc = {
+	.type = AFB_BINDING_VERSION_1,
+	.v1 = {
+		.info = "CAN bus service",
+		.prefix = "can",
+		.verbs = verbs
+	}
+};
+
+const struct afb_binding *afbBindingV1Register (const struct afb_binding_interface *itf)
+{
+	interface = itf;
+
+	return &binding_desc;
+}
+
+int afbBindingV1ServiceInit(struct afb_service service)
+{
+	/* Open CAN socket */
+	retry(open_can_dev);
+	return connect_to_event_loop();
+}