/* SPDX-FileCopyrightText: 2016, Matthias Schiffer <mschiffer@universe-factory.net> */
/* SPDX-License-Identifier: BSD-2-Clause */


#include <respondd.h>

#include <json-c/json.h>
#include <libgluonutil.h>
#include <uci.h>

#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#include <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <ifaddrs.h>

#include <netdb.h>
#include <errno.h>
#include <libbabelhelper/babelhelper.h>

#include <libubox/blobmsg_json.h>
#include <libubus.h>

#define SOCKET_INPUT_BUFFER_SIZE 255

#define PROTOLEN 32

#define UBUS_TIMEOUT 30000

static struct babelhelper_ctx bhelper_ctx = {};

static bool get_linklocal_address(const char *ifname, char lladdr[INET6_ADDRSTRLEN]) {
	struct ifaddrs *ifaddr, *ifa;
	bool ret = false;

	if (getifaddrs(&ifaddr) == -1) {
		perror("getifaddrs");
		return false;
	}

	for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
		if (!ifa->ifa_addr)
			continue;

		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;

		if (strcmp(ifname, ifa->ifa_name) != 0)
			continue;

		const struct in6_addr *address = &((const struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
		if (!IN6_IS_ADDR_LINKLOCAL(address))
			continue;

		if (!inet_ntop(AF_INET6, address, lladdr, INET6_ADDRSTRLEN)) {
			perror("inet_ntop");
			continue;
		}

		ret = true;
		break;
	}

	freeifaddrs(ifaddr);
	return ret;
}


static char*  get_line_from_run(const char* command) {
	FILE *fp;
	char *line = NULL;
	size_t len = 0;

	fp = popen(command, "r");

	if (fp != NULL) {
		ssize_t r = getline(&line, &len, fp);
		if (r >= 0) {
			len = strlen(line);

			if (len && line[len-1] == '\n')
				line[len-1] = 0;
		}
		else {
			free(line);
			line = NULL;
		}

		pclose(fp);
	}
	return line;
}

static struct json_object * get_addresses(void) {
	char *primarymac = gluonutil_get_sysconfig("primary_mac");
	char *address = malloc(INET6_ADDRSTRLEN+1);
	char node_prefix_str[INET6_ADDRSTRLEN+1];
	struct in6_addr node_prefix = {};
	struct json_object *retval = json_object_new_array();

	if (!gluonutil_get_node_prefix6(&node_prefix)) {
		fprintf(stderr, "get_addresses: could not obtain mesh-prefix from site.conf. Not adding addresses to json data\n");
		goto free;
	}

	if (inet_ntop(AF_INET6, &(node_prefix.s6_addr), node_prefix_str, INET6_ADDRSTRLEN) == NULL) {
		fprintf(stderr, "get_addresses: could not convert mesh-prefix from site.conf to string\n");
		goto free;
	}

	char *prefix_addresspart = strndup(node_prefix_str, INET6_ADDRSTRLEN);
	if (! babelhelper_generateip_str(address, primarymac, prefix_addresspart) ) {
		fprintf(stderr, "IP-address could not be generated by babelhelper");
	}
	free(prefix_addresspart);

	json_object_array_add(retval, json_object_new_string(address));

free:
	free(address);
	free(primarymac);

	return retval;
}

static void mesh_add_if(const char *ifname, struct json_object *wireless,
		struct json_object *tunnel, struct json_object *other) {
	char str_ip[INET6_ADDRSTRLEN];

	if (!get_linklocal_address(ifname, str_ip))
		return;

	struct json_object *address = json_object_new_string(str_ip);

	/* In case of VLAN and bridge interfaces, we want the lower interface
	 * to determine the interface type (but not for the interface address) */
	char lowername[IF_NAMESIZE];
	gluonutil_get_interface_lower(lowername, ifname);

	switch(gluonutil_get_interface_type(lowername)) {
	case GLUONUTIL_INTERFACE_TYPE_WIRELESS:
		json_object_array_add(wireless, address);
		break;

	case GLUONUTIL_INTERFACE_TYPE_TUNNEL:
		json_object_array_add(tunnel, address);
		break;

	default:
		json_object_array_add(other, address);
	}
}


static bool handle_neighbour(char **data, void *obj) {
	if (data[NEIGHBOUR]) {
		struct json_object *neigh = json_object_new_object();

		if (data[RXCOST])
			json_object_object_add(neigh, "rxcost", json_object_new_int(atoi(data[RXCOST])));
		if (data[TXCOST])
			json_object_object_add(neigh, "txcost", json_object_new_int(atoi(data[TXCOST])));
		if (data[COST])
			json_object_object_add(neigh, "cost", json_object_new_int(atoi(data[COST])));
		if (data[REACH])
			json_object_object_add(neigh, "reachability", json_object_new_double(strtod(data[REACH], NULL)));

		if (!data[IF])
			return true;

		struct json_object *nif;
		if (!json_object_object_get_ex(obj, data[IF], &nif)) {
			char str_ip[INET6_ADDRSTRLEN];

			nif = json_object_new_object();

			if (get_linklocal_address(data[IF], str_ip))
				json_object_object_add(nif, "ll-addr", json_object_new_string(str_ip));

			json_object_object_add(nif, "protocol", json_object_new_string("babel"));
			json_object_object_add(obj, data[IF], nif);

			json_object_object_add(nif, "neighbours", json_object_new_object());
		}

		struct json_object *neighborcollector;
		json_object_object_get_ex(nif, "neighbours", &neighborcollector);
		json_object_object_add(neighborcollector, data[ADDRESS], neigh);

	}
	return true;
}

static struct json_object * get_babel_neighbours(void) {

	struct json_object *neighbours;
	neighbours  = json_object_new_object();
	if (!neighbours)
		return NULL;

	babelhelper_readbabeldata(&bhelper_ctx, "dump", (void*)neighbours, handle_neighbour);

	return(neighbours);
}

static void blobmsg_handle_list(struct blob_attr *attr, int len, bool array, struct json_object *wireless, struct json_object *tunnel, struct json_object *other);

static void blobmsg_handle_element(struct blob_attr *attr, bool head, char **ifname, char **proto, struct json_object *wireless, struct json_object *tunnel, struct json_object *other) {
	void *data;

	if (!blobmsg_check_attr(attr, false))
		return;

	data = blobmsg_data(attr);

	switch (blob_id(attr)) {
		case  BLOBMSG_TYPE_STRING:
			if (!strncmp(blobmsg_name(attr), "device", 6)) {
				free(*ifname);
				*ifname = strndup(data, IF_NAMESIZE);
			} else if (!strncmp(blobmsg_name(attr), "proto", 5)) {
				free(*proto);
				*proto = strndup(data, PROTOLEN);
			}
			return;
		case BLOBMSG_TYPE_ARRAY:
			blobmsg_handle_list(data, blobmsg_data_len(attr), true, wireless, tunnel, other);
			return;
		case BLOBMSG_TYPE_TABLE:
			blobmsg_handle_list(data, blobmsg_data_len(attr), false, wireless, tunnel, other);
	}
}

static void blobmsg_handle_list(struct blob_attr *attr, int len, bool array, struct json_object *wireless, struct json_object *tunnel, struct json_object *other) {
	struct blob_attr *pos;
	int rem = len;

	char *ifname = NULL;
	char *proto = NULL;

	__blob_for_each_attr(pos, attr, rem) {
		blobmsg_handle_element(pos, array, &ifname, &proto, wireless, tunnel, other);
	}

	if (ifname && proto) {
		if (!strncmp(proto, "gluon_mesh", 10)) {
			mesh_add_if(ifname, wireless, tunnel, other);
		}
	}
	free(ifname);
	free(proto);
}

static void add_if_not_empty(struct json_object *obj, const char *key, struct json_object *val) {
	if (json_object_array_length(val))
		json_object_object_add(obj, key, val);
	else
		json_object_put(val);
}

static void receive_call_result_data(struct ubus_request *req, int type, struct blob_attr *msg) {
	struct json_object *ret = json_object_new_object();
	struct json_object *wireless = json_object_new_array();
	struct json_object *tunnel = json_object_new_array();
	struct json_object *other = json_object_new_array();

	if (!ret || !wireless || !tunnel || !other) {
		json_object_put(wireless);
		json_object_put(tunnel);
		json_object_put(other);
		json_object_put(ret);
		return;
	}

	if (!msg) {
		printf("empty message\n");
		return;
	}

	blobmsg_handle_list(blobmsg_data(msg), blobmsg_data_len(msg), false, wireless, tunnel, other);

	add_if_not_empty(ret, "wireless", wireless);
	add_if_not_empty(ret, "tunnel", tunnel);
	add_if_not_empty(ret, "other", other);

	*((struct json_object**)(req->priv)) = ret;
}


static struct json_object * get_mesh_ifs() {
	struct ubus_context *ubus_ctx;
	struct json_object *ret = NULL;
	struct blob_buf b = {};

	unsigned int id=8;

	ubus_ctx = ubus_connect(NULL);
	if (!ubus_ctx) {
		fprintf(stderr,"could not connect to ubus, not providing mesh-data\n");
		goto end;
	}

	blob_buf_init(&b, 0);
	ubus_lookup_id(ubus_ctx, "network.interface", &id);
	int uret = ubus_invoke(ubus_ctx, id, "dump", b.head, receive_call_result_data, &ret, UBUS_TIMEOUT);

	if (uret > 0)
		fprintf(stderr, "ubus command failed: %s\n", ubus_strerror(uret));
	else if (uret == -2)
		fprintf(stderr, "invalid call, exiting\n");

	blob_buf_free(&b);

end:
	ubus_free(ubus_ctx);
	return ret;
}

static struct json_object * get_mesh(void) {
	struct json_object *ret = json_object_new_object();
	struct json_object *interfaces = NULL;
	interfaces = json_object_new_object();
	json_object_object_add(interfaces, "interfaces", get_mesh_ifs());
	json_object_object_add(ret, "babel", interfaces);
	return ret;
}

static struct json_object * get_babeld_version(void) {
	char *version = get_line_from_run("exec babeld -V 2>&1");
	struct json_object *ret = gluonutil_wrap_string(version);
	free(version);
	return ret;
}

static struct json_object * respondd_provider_nodeinfo(void) {
	bhelper_ctx.debug=false;
	struct json_object *ret = json_object_new_object();

	struct json_object *network = json_object_new_object();
	json_object_object_add(network, "addresses", get_addresses());
	json_object_object_add(network, "mesh", get_mesh());
	json_object_object_add(ret, "network", network);

	struct json_object *software = json_object_new_object();
	struct json_object *software_babeld = json_object_new_object();
	json_object_object_add(software_babeld, "version", get_babeld_version());
	json_object_object_add(software, "babeld", software_babeld);
	json_object_object_add(ret, "software", software);

	return ret;
}

static struct json_object * read_number(const char *ifname, const char *stat) {
	const char *format = "/sys/class/net/%s/statistics/%s";

	struct json_object *ret = NULL;
	int64_t i;

	char path[strlen(format) + strlen(ifname) + strlen(stat) + 1];
	snprintf(path, sizeof(path), format, ifname, stat);

	FILE *f = fopen(path, "r");
	if (!f)
		return NULL;

	if (fscanf(f, "%"SCNd64, &i) == 1)
		ret = json_object_new_int64(i);

	fclose(f);

	return ret;
}

static struct json_object * get_traffic(void) {
	const char *ifname = "br-client";

	struct json_object *ret = NULL;
	struct json_object *rx = json_object_new_object();
	struct json_object *tx = json_object_new_object();

	json_object_object_add(rx, "packets", read_number(ifname, "rx_packets"));
	json_object_object_add(rx, "bytes", read_number(ifname, "rx_bytes"));
	json_object_object_add(rx, "dropped", read_number(ifname, "rx_dropped"));
	json_object_object_add(tx, "packets", read_number(ifname, "tx_packets"));
	json_object_object_add(tx, "dropped", read_number(ifname, "tx_dropped"));
	json_object_object_add(tx, "bytes", read_number(ifname, "tx_bytes"));

	ret = json_object_new_object();
	json_object_object_add(ret, "rx", rx);
	json_object_object_add(ret, "tx", tx);

	return ret;
}

static bool handle_route_addgw_nexthop(char **data, void *arg) {
	struct json_object *obj = (struct json_object*) arg;
	if (data[PREFIX] && data[FROM] && data[VIA] && data[IF]) {
		if ( (! strncmp(data[PREFIX], "::/0", 4) ) && ( ! strncmp(data[FROM], "::/0", 4) ) ) {
			int gw_nexthoplen=strlen(data[VIA]) + strlen(data[IF])+2;
			char gw_nexthop[gw_nexthoplen];
			snprintf(gw_nexthop, gw_nexthoplen , "%s%%%s", data[VIA], data[IF]);
			json_object_object_add(obj, "gateway_nexthop", json_object_new_string(gw_nexthop));
		}
	}
	return true;
}

static int json_parse_get_clients(json_object * object) {
	if (object) {
		json_object_object_foreach(object, key, val) {
			if (! strncmp("clients", key, 7)) {
				return(json_object_get_int(val));
			}
		}
	}
	return(-1);
}

static int ask_l3roamd_for_client_count() {
	struct sockaddr_un addr;
	const char *socket_path = "/var/run/l3roamd.sock";
	int fd;
	int clients = -1;
	char *buf = NULL;
	int already_read = 0;

	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
		fprintf(stderr, "could not setup l3roamd-control-socket\n");
		return(-1);
	}

	memset(&addr, 0, sizeof(addr));
	addr.sun_family = AF_UNIX;
	strncpy(addr.sun_path, socket_path, sizeof(addr.sun_path)-1);

	if (connect(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
		fprintf(stderr, "connect error\n");
		return(-1);
	}

	if (write(fd,"get_clients\n",12) != 12) {
		perror("could not send command to l3roamd socket: get_clients");
		goto end;
	}

	int rc = 0;
	do {
		char *buf_tmp = realloc(buf, already_read + SOCKET_INPUT_BUFFER_SIZE + 1);
		if (buf_tmp == NULL) {
			fprintf(stderr, "could not allocate memory for buffer\n");
			goto end;
		}
		buf = buf_tmp;

		rc = read(fd, &buf[already_read], SOCKET_INPUT_BUFFER_SIZE);
		already_read+=rc;
		if (rc < 0) {
			perror("error on read in ask_l3roamd_for_client_count():");
			goto end;
		}
		buf[already_read]='\0';
	} while (rc == SOCKET_INPUT_BUFFER_SIZE);

	json_object * jobj = json_tokener_parse(buf);
	clients = json_parse_get_clients(jobj);
	json_object_put(jobj);

end:
	free(buf);
	close(fd);

	return clients;
}

static struct json_object * get_clients(void) {
	struct json_object *ret = json_object_new_object();

	int total = ask_l3roamd_for_client_count();
	if (total >= 0)
		json_object_object_add(ret, "total", json_object_new_int(total));

	return ret;
}

static struct json_object * respondd_provider_statistics(void) {
	struct json_object *ret = json_object_new_object();

	json_object_object_add(ret, "clients", get_clients());
	json_object_object_add(ret, "traffic", get_traffic());

	babelhelper_readbabeldata(&bhelper_ctx, "dump", (void*)ret, handle_route_addgw_nexthop );

	return ret;
}

static struct json_object * respondd_provider_neighbours(void) {
	struct json_object *ret = json_object_new_object();

	struct json_object *babel = get_babel_neighbours();
	if (babel)
		json_object_object_add(ret, "babel", babel);


	return ret;
}


const struct respondd_provider_info respondd_providers[] = {
	{"nodeinfo", respondd_provider_nodeinfo},
	{"statistics", respondd_provider_statistics},
	{"neighbours", respondd_provider_neighbours},
	{}
};