/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2019 Jan Sucan <jansucan@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/socket.h>

#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>

#include <err.h>
#include <math.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>

#include "main.h"
#ifdef INET
#include "ping.h"
#endif
#ifdef INET6
#include "ping6.h"
#endif

#if defined(INET) && defined(INET6)
#define OPTSTR PING6OPTS PING4OPTS
#elif defined(INET)
#define OPTSTR PING4OPTS
#elif defined(INET6)
#define OPTSTR PING6OPTS
#else
#error At least one of INET and INET6 is required
#endif

/* various options */
u_int options;

char *hostname;

/* counters */
long nreceived;         /* # of packets we got back */
long nrepeats;          /* number of duplicates */
long ntransmitted;      /* sequence # for outbound packets = #sent */
long nrcvtimeout = 0;   /* # of packets we got back after waittime */

/* nonzero if we've been told to finish up */
volatile sig_atomic_t seenint;
volatile sig_atomic_t seeninfo;

/* timing */
int timing;             /* flag to do timing */
double tmin = 999999999.0;      /* minimum round trip time */
double tmax = 0.0;      /* maximum round trip time */
double tsum = 0.0;      /* sum of all times, for doing average */
double tsumsq = 0.0;    /* sum of all times squared, for std. dev. */

int
main(int argc, char *argv[])
{
#if defined(INET)
        struct in_addr a;
#endif
#if defined(INET6)
        struct in6_addr a6;
#endif
#if defined(INET) && defined(INET6)
        struct addrinfo hints, *res, *ai;
        const char *target;
        int error;
#endif
        int opt;

#ifdef INET6
        if (strcmp(getprogname(), "ping6") == 0)
                return ping6(argc, argv);
#endif

        while ((opt = getopt(argc, argv, ":" OPTSTR)) != -1) {
                switch (opt) {
#ifdef INET
                case '4':
                        goto ping4;
#endif
#ifdef INET6
                case '6':
                        goto ping6;
#endif
                case 'S':
                        /*
                         * If -S is given with a numeric parameter,
                         * force use of the corresponding version.
                         */
#ifdef INET
                        if (inet_pton(AF_INET, optarg, &a) == 1)
                                goto ping4;
#endif
#ifdef INET6
                        if (inet_pton(AF_INET6, optarg, &a6) == 1)
                                goto ping6;
#endif
                        break;
                default:
                        break;
                }
        }

        /*
         * For IPv4, only one positional argument, the target, is allowed.
         * For IPv6, multiple positional argument are allowed; the last
         * one is the target, and preceding ones are intermediate hops.
         * This nuance is lost here, but the only case where it matters is
         * an error.
         */
        if (optind >= argc)
                usage();

#if defined(INET) && defined(INET6)
        target = argv[argc - 1];
        memset(&hints, 0, sizeof(hints));
        hints.ai_socktype = SOCK_RAW;
        if (feature_present("inet") && !feature_present("inet6"))
                hints.ai_family = AF_INET;
        else if (feature_present("inet6") && !feature_present("inet"))
                hints.ai_family = AF_INET6;
        else
                hints.ai_family = AF_UNSPEC;
        error = getaddrinfo(target, NULL, &hints, &res);
        if (res == NULL)
                errx(EX_NOHOST, "cannot resolve %s: %s",
                    target, gai_strerror(error));
        for (ai = res; ai != NULL; ai = ai->ai_next) {
                if (ai->ai_family == AF_INET) {
                        freeaddrinfo(res);
                        goto ping4;
                }
                if (ai->ai_family == AF_INET6) {
                        freeaddrinfo(res);
                        goto ping6;
                }
        }
        freeaddrinfo(res);
        errx(EX_NOHOST, "cannot resolve %s", target);
#endif
#ifdef INET
ping4:
        optreset = 1;
        optind = 1;
        return ping(argc, argv);
#endif
#ifdef INET6
ping6:
        optreset = 1;
        optind = 1;
        return ping6(argc, argv);
#endif
}

/*
 * onsignal --
 *      Set the global bit that causes the main loop to quit.
 */
void
onsignal(int sig)
{
        switch (sig) {
        case SIGALRM:
        case SIGINT:
                /*
                 * When doing reverse DNS lookups, the seenint flag might not
                 * be noticed for a while.  Just exit if we get a second SIGINT.
                 */
                if (!(options & F_HOSTNAME) && seenint != 0)
                        _exit(nreceived ? 0 : 2);
                seenint++;
                break;
        case SIGINFO:
                seeninfo++;
                break;
        }
}

/*
 * pr_summary --
 *      Print out summary statistics to the given output stream.
 */
void
pr_summary(FILE * restrict stream)
{
        fprintf(stream, "\n--- %s ping statistics ---\n", hostname);
        fprintf(stream, "%ld packets transmitted, ", ntransmitted);
        fprintf(stream, "%ld packets received, ", nreceived);
        if (nrepeats)
                fprintf(stream, "+%ld duplicates, ", nrepeats);
        if (ntransmitted) {
                if (nreceived > ntransmitted)
                        fprintf(stream, "-- somebody's duplicating packets!");
                else
                        fprintf(stream, "%.1f%% packet loss",
                            ((((double)ntransmitted - nreceived) * 100.0) /
                            ntransmitted));
        }
        if (nrcvtimeout)
                fprintf(stream, ", %ld packets out of wait time", nrcvtimeout);
        fputc('\n', stream);
        if (nreceived && timing) {
                /* Only display average to microseconds */
                double num = nreceived + nrepeats;
                double avg = tsum / num;
                double stddev = sqrt(fmax(0, tsumsq / num - avg * avg));
                fprintf(stream,
                    "round-trip min/avg/max/stddev = %.3f/%.3f/%.3f/%.3f ms\n",
                    tmin, avg, tmax, stddev);
        }
        fflush(stream);
}

void
usage(void)
{
        (void)fprintf(stderr,
            "usage:\n"
#ifdef INET
            "\tping [-4AaDdfHnoQqRrv] [-C pcp] [-c count] "
            "[-G sweepmaxsize]\n"
            "\t    [-g sweepminsize] [-h sweepincrsize] [-i wait] "
            "[-l preload]\n"
            "\t    [-M mask | time] [-m ttl] "
#ifdef IPSEC
            "[-P policy] "
#endif
            "[-p pattern] [-S src_addr] \n"
            "\t    [-s packetsize] [-t timeout] [-W waittime] [-z tos] "
            "IPv4-host\n"
            "\tping [-4AaDdfHLnoQqRrv] [-C pcp] [-c count] [-I iface] "
            "[-i wait]\n"
            "\t    [-l preload] [-M mask | time] [-m ttl] "
#ifdef IPSEC
            "[-P policy] "
#endif
            "[-p pattern]\n"
            "\t    [-S src_addr] [-s packetsize] [-T ttl] [-t timeout] [-W waittime]\n"
            "\t    [-z tos] IPv4-mcast-group\n"
#endif /* INET */
#ifdef INET6
            "\tping [-6AaDd"
#if defined(IPSEC) && !defined(IPSEC_POLICY_IPSEC)
            "E"
#endif
            "fHnNoOq"
#ifdef IPV6_USE_MIN_MTU
            "u"
#endif
            "vyY"
#if defined(IPSEC) && !defined(IPSEC_POLICY_IPSEC)
            "Z"
#endif
            "] "
            "[-b bufsiz] [-C pcp] [-c count] [-e gateway]\n"
            "\t    [-I interface] [-i wait] [-k addrtype] [-l preload] "
            "[-m hoplimit]\n"
            "\t    [-p pattern]"
#if defined(IPSEC) && defined(IPSEC_POLICY_IPSEC)
            " [-P policy]"
#endif
            " [-S sourceaddr] [-s packetsize] [-t timeout]\n"
            "\t    [-W waittime] [-z tclass] [IPv6-hops ...] IPv6-host\n"
#endif  /* INET6 */
            );

        exit(1);
}