// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) B.A.T.M.A.N. contributors:
 *
 * Andreas Langer <an.langer@gmx.de>, Marek Lindner <marek.lindner@mailbox.org>
 *
 * License-Filename: LICENSES/preferred/GPL-2.0
 */

#include <netinet/in.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <string.h>
#include <math.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
#include <netinet/if_ether.h>

#include "batadv_packet_compat.h"
#include "main.h"
#include "functions.h"
#include "bat-hosts.h"
#include "icmp_helper.h"

static volatile sig_atomic_t is_aborted;

static void ping_usage(void)
{
	fprintf(stderr, "Usage: batctl [options] ping [parameters] mac|bat-host|host_name|IPv4_address\n");
	fprintf(stderr, "parameters:\n");
	fprintf(stderr, " \t -c ping packet count\n");
	fprintf(stderr, " \t -h print this help\n");
	fprintf(stderr, " \t -i interval in seconds\n");
	fprintf(stderr, " \t -t timeout in seconds\n");
	fprintf(stderr, " \t -R record route\n");
	fprintf(stderr, " \t -T don't try to translate mac to originator address\n");
}

static void sig_handler(int sig)
{
	switch (sig) {
	case SIGINT:
	case SIGTERM:
		is_aborted = 1;
		break;
	default:
		break;
	}
}

static int ping(struct state *state, int argc, char **argv)
{
	struct batadv_icmp_packet_rr icmp_packet_out;
	struct batadv_icmp_packet_rr icmp_packet_in;
	uint8_t last_rr[BATADV_RR_LEN][ETH_ALEN];
	struct timespec loop_interval = {0, 0};
	struct ether_addr *dst_mac = NULL;
	struct ether_addr *rr_mac = NULL;
	int disable_translate_mac = 0;
	double fractional_part = 0.0;
	unsigned int seq_counter = 0;
	unsigned int packets_out = 0;
	unsigned int packets_in = 0;
	double ping_interval = 0.0;
	double integral_part = 0.0;
	unsigned int packets_loss;
	struct bat_host *bat_host;
	struct bat_host *rr_host;
	uint8_t last_rr_cur = 0;
	int ret = EXIT_FAILURE;
	int loop_count = -1;
	int found_args = 1;
	size_t packet_len;
	struct timeval tv;
	double time_delta;
	float mdev = 0.0;
	ssize_t read_len;
	char *dst_string;
	char *mac_string;
	char *rr_string;
	float min = 0.0;
	float max = 0.0;
	float avg = 0.0;
	int timeout = 1;
	char *endptr;
	int optchar;
	int rr = 0;
	int res;
	int i;

	while ((optchar = getopt(argc, argv, "hc:i:t:RT")) != -1) {
		switch (optchar) {
		case 'c':
			loop_count = strtol(optarg, NULL, 10);
			if (loop_count < 1)
				loop_count = -1;
			found_args += ((*((char *)(optarg - 1)) == optchar) ? 1 : 2);
			break;
		case 'h':
			ping_usage();
			return EXIT_SUCCESS;
		case 'i':
			errno = 0;
			ping_interval = strtod(optarg, &endptr);
			if (errno || *endptr != '\0') {
				fprintf(stderr, "Error - invalid ping interval '%s'\n", optarg);
				goto out;
			}

			ping_interval = fmax(ping_interval, 0.001);
			fractional_part = modf(ping_interval, &integral_part);
			loop_interval.tv_sec = (time_t)integral_part;
			loop_interval.tv_nsec = (long)(fractional_part * 1000000000l);
			found_args += ((*((char *)(optarg - 1)) == optchar) ? 1 : 2);
			break;
		case 't':
			timeout = strtol(optarg, NULL, 10);
			if (timeout < 1)
				timeout = 1;
			found_args += ((*((char *)(optarg - 1)) == optchar) ? 1 : 2);
			break;
		case 'R':
			rr = 1;
			found_args++;
			break;
		case 'T':
			disable_translate_mac = 1;
			found_args += 1;
			break;
		default:
			ping_usage();
			return EXIT_FAILURE;
		}
	}

	if (argc <= found_args) {
		fprintf(stderr, "Error - target mac address or bat-host name not specified\n");
		ping_usage();
		return EXIT_FAILURE;
	}

	dst_string = argv[found_args];
	bat_hosts_init(0);
	bat_host = bat_hosts_find_by_name(dst_string);

	if (bat_host)
		dst_mac = &bat_host->mac_addr;

	if (!dst_mac) {
		dst_mac = resolve_mac(dst_string);

		if (!dst_mac) {
			fprintf(stderr,
				"Error - mac address of the ping destination could not be resolved and is not a bat-host name: %s\n",
				dst_string);
			goto out;
		}
	}

	if (!disable_translate_mac)
		dst_mac = translate_mac(state, dst_mac);

	mac_string = ether_ntoa_long(dst_mac);
	signal(SIGINT, sig_handler);
	signal(SIGTERM, sig_handler);

	icmp_interfaces_init();
	packet_len = sizeof(struct batadv_icmp_packet);

	memset(&icmp_packet_out, 0, sizeof(icmp_packet_out));
	memcpy(&icmp_packet_out.dst, dst_mac, ETH_ALEN);
	icmp_packet_out.packet_type = BATADV_ICMP;
	icmp_packet_out.version = BATADV_COMPAT_VERSION;
	icmp_packet_out.msg_type = BATADV_ECHO_REQUEST;
	icmp_packet_out.ttl = 50;
	icmp_packet_out.seqno = 0;

	if (rr) {
		packet_len = sizeof(struct batadv_icmp_packet_rr);
		icmp_packet_out.rr_cur = 1;
		memset(&icmp_packet_out.rr, 0, BATADV_RR_LEN * ETH_ALEN);
		memset(last_rr, 0, BATADV_RR_LEN * ETH_ALEN);
	} else {
		((struct batadv_icmp_packet *)&icmp_packet_out)->reserved = 0;
	}

	printf("PING %s (%s) %zu(%zu) bytes of data\n", dst_string, mac_string,
	       packet_len, packet_len + 28);

	while (!is_aborted) {
		tv.tv_sec = timeout;
		tv.tv_usec = 0;

		if (loop_count == 0)
			break;

		if (loop_count > 0)
			loop_count--;

		icmp_packet_out.seqno = htons(++seq_counter);

		res = icmp_interface_write(state,
					   (struct batadv_icmp_header *)&icmp_packet_out,
					   packet_len);
		if (res < 0) {
			fprintf(stderr, "Error - can't send icmp packet: %s\n", strerror(-res));
			goto sleep;
		}

read_packet:
		start_timer();

		read_len = icmp_interface_read((struct batadv_icmp_header *)&icmp_packet_in,
					       packet_len, &tv);

		if (is_aborted)
			break;

		packets_out++;

		if (read_len == 0) {
			printf("Reply from host %s timed out\n", dst_string);
			goto sleep;
		}

		if (read_len < 0) {
			fprintf(stderr, "Error - can't receive icmp packets: %s\n",
				strerror(-read_len));
			goto sleep;
		}

		if ((size_t)read_len < packet_len) {
			printf("Warning - dropping received packet as it is smaller than expected (%zu): %zd\n",
			       packet_len, read_len);
			goto sleep;
		}

		/* after receiving an unexpected seqno we keep waiting for our answer */
		if (htons(seq_counter) != icmp_packet_in.seqno)
			goto read_packet;

		switch (icmp_packet_in.msg_type) {
		case BATADV_ECHO_REPLY:
			time_delta = end_timer();
			printf("%zd bytes from %s icmp_seq=%hu ttl=%d time=%.2f ms",
			       read_len, dst_string,
			       ntohs(icmp_packet_in.seqno),
			       icmp_packet_in.ttl,
			       time_delta);

			if (read_len == sizeof(struct batadv_icmp_packet_rr)) {
				if (last_rr_cur == icmp_packet_in.rr_cur &&
				    !memcmp(last_rr, icmp_packet_in.rr, BATADV_RR_LEN * ETH_ALEN)) {
					printf("\t(same route)");
				} else {
					printf("\nRR: ");

					for (i = 0; i < BATADV_RR_LEN && i < icmp_packet_in.rr_cur; i++) {
						rr_mac = (struct ether_addr *)&icmp_packet_in.rr[i];
						rr_host = bat_hosts_find_by_mac((char *)rr_mac);
						if (rr_host)
							rr_string = rr_host->name;
						else
							rr_string = ether_ntoa_long(rr_mac);
						printf("\t%s\n", rr_string);

						if (memcmp(rr_mac, dst_mac, ETH_ALEN) == 0)
							printf("\t%s\n", rr_string);
					}

					last_rr_cur = icmp_packet_in.rr_cur;
					memcpy(last_rr, icmp_packet_in.rr,
					       BATADV_RR_LEN * ETH_ALEN);
				}
			}

			printf("\n");

			if (time_delta < min || min == 0.0)
				min = time_delta;
			if (time_delta > max)
				max = time_delta;
			avg += time_delta;
			mdev += time_delta * time_delta;
			packets_in++;
			break;
		case BATADV_DESTINATION_UNREACHABLE:
			printf("From %s: Destination Host Unreachable (icmp_seq %hu)\n",
			       dst_string, ntohs(icmp_packet_in.seqno));
			break;
		case BATADV_TTL_EXCEEDED:
			printf("From %s: Time to live exceeded (icmp_seq %hu)\n",
			       dst_string, ntohs(icmp_packet_in.seqno));
			break;
		case BATADV_PARAMETER_PROBLEM:
			fprintf(stderr,
				"Error - the batman adv kernel module version (%d) differs from ours (%d)\n",
				icmp_packet_in.version, BATADV_COMPAT_VERSION);
			printf("Please make sure to use compatible versions!\n");
			goto out;
		default:
			printf("Unknown message type %d len %zd received\n",
			       icmp_packet_in.msg_type, read_len);
			break;
		}

sleep:
		/* skip last sleep in case no more packets will be sent out */
		if (loop_count == 0)
			continue;

		if (loop_interval.tv_sec > 0 || loop_interval.tv_nsec > 0)
			nanosleep(&loop_interval, NULL);
		else if ((tv.tv_sec != 0) || (tv.tv_usec != 0))
			select(0, NULL, NULL, NULL, &tv);
	}

	if (packets_out == 0)
		packets_loss = 0;
	else
		packets_loss = ((packets_out - packets_in) * 100) / packets_out;

	if (packets_in) {
		avg /= packets_in;
		mdev /= packets_in;
		mdev = mdev - avg * avg;
		if (mdev > 0.0)
			mdev = sqrt(mdev);
		else
			mdev = 0.0;
	} else {
		avg = 0.0;
		mdev = 0.0;
	}

	printf("--- %s ping statistics ---\n", dst_string);
	printf("%u packets transmitted, %u received, %u%% packet loss\n",
	       packets_out, packets_in, packets_loss);
	printf("rtt min/avg/max/mdev = %.3f/%.3f/%.3f/%.3f ms\n",
	       min, avg, max, mdev);

	if (packets_in)
		ret = EXIT_SUCCESS;
	else
		ret = EXIT_NOSUCCESS;

out:
	icmp_interfaces_clean();
	bat_hosts_free();
	return ret;
}

COMMAND(SUBCOMMAND_MIF, ping, "p",
	COMMAND_FLAG_MESH_IFACE | COMMAND_FLAG_NETLINK, NULL,
	"<destination>     \tping another batman adv host via layer 2");