/*      $NetBSD: npfd.c,v 1.9 2017/10/16 11:18:43 christos Exp $        */

/*-
 * Copyright (c) 2015 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Mindaugas Rasiukevicius.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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/cdefs.h>
__RCSID("$NetBSD: npfd.c,v 1.9 2017/10/16 11:18:43 christos Exp $");

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdbool.h>
#include <poll.h>
#include <errno.h>
#include <err.h>
#include <syslog.h>
#include <util.h>

#include <net/npf.h>

#include "npfd.h"

static volatile sig_atomic_t hup, stats, done, flush;

static int
npfd_getctl(void)
{
        int fd, ver;

        fd = open(NPF_DEV_PATH, O_RDONLY);
        if (fd == -1) {
                err(EXIT_FAILURE, "cannot open '%s'", NPF_DEV_PATH);
        }
        if (ioctl(fd, IOC_NPF_VERSION, &ver) == -1) {
                err(EXIT_FAILURE, "ioctl(IOC_NPF_VERSION)");
        }
        if (ver != NPF_VERSION) {
                errx(EXIT_FAILURE,
                    "Incompatible NPF interface version (%d, kernel %d)\n"
                    "Hint: update userland?", NPF_VERSION, ver);
        }
        return fd;
}

static void
npfd_event_loop(npfd_log_t *log, int delay)
{
        struct pollfd pfd;
        size_t count = 0;

        pfd.fd = npfd_log_getsock(log);
        pfd.events = POLLHUP | POLLIN;

        while  (!done) {
                if (hup) {
                        hup = false;
                        npfd_log_file_reopen(log, false);
                }
                if (stats) {
                        stats = false;
                        npfd_log_stats(log);
                }
                if (flush) {
                        flush = false;
                        npfd_log_flush(log);
                        count = 0;
                }
                switch (poll(&pfd, 1, delay)) {
                case -1:
                        if (errno == EINTR)
                                continue;
                        syslog(LOG_ERR, "poll failed: %m");
                        exit(EXIT_FAILURE);
                        /*NOTREACHED*/
                case 0:
                        npfd_log_flush(log);
                        count = 0;
                        continue;
                default:
                        if (count++ >= 100) {
                                npfd_log_flush(log);
                                count = 0;
                        }
                        if (npfd_log(log) <= 0)
                                npfd_log_pcap_reopen(log);
                }

        }
        npfd_log_destroy(log);
}

static void
sighandler(int sig)
{
        switch (sig) {
        case SIGHUP:
                hup = true;
                break;
        case SIGTERM:
        case SIGINT:
                done = true;
                break;
        case SIGINFO:
                stats = true;
                break;
        case SIGALRM:
                flush = true;
                break;
        default:
                syslog(LOG_ERR, "Unhandled signal %d", sig);
                break;
        }
}

static __dead void
usage(void)
{
        fprintf(stderr, "Usage: %s [-D] [-d <delay>] [-i <interface>]"
            " [-f <filename>] [-p <pidfile>] [-s <snaplen>] expression\n",
            getprogname());
        exit(EXIT_FAILURE);
}

static char *
copyargs(int argc, char **argv)
{
        if (argc == 0)
                return NULL;

        size_t len = 0, p = 0;
        char *buf = NULL;

        for (int i = 0; i < argc; i++) {
                size_t l = strlen(argv[i]);
                if (p + l + 1 >= len)
                        buf = erealloc(buf, len = p + l + 1);
                memcpy(buf + p, argv[i], l);
                p += l;
                buf[p++] = i == argc - 1 ? '\0' : ' ';
        }
        return buf;
}

int
main(int argc, char **argv)
{
        bool daemon_off = false;
        int ch;

        int delay = 5 * 1000;
        const char *iface = "npflog0";
        int snaplen = 116;
        char *pidname = NULL;
        char *filename = NULL;

        int fd = npfd_getctl();
        (void)close(fd);

        while ((ch = getopt(argc, argv, "Dd:f:i:p:s:")) != -1) {
                switch (ch) {
                case 'D':
                        daemon_off = true;
                        break;
                case 'd':
                        delay = atoi(optarg) * 1000;
                        break;
                case 'f':
                        filename = optarg;
                        break;
                case 'i':
                        iface = optarg;
                        break;
                case 'p':
                        pidname = optarg;
                        break;
                case 's':
                        snaplen = atoi(optarg);
                        break;
                default:
                        usage();
                }
        }

        argc -= optind;
        argv += optind;

        char *filter = copyargs(argc, argv);

        npfd_log_t *log = npfd_log_create(filename, iface, filter, snaplen);

        if (!daemon_off) {
                if (daemon(0, 0) == -1)
                        err(EXIT_FAILURE, "daemon");
                pidfile(pidname);
        }

        openlog(argv[0], LOG_PID | LOG_NDELAY | LOG_CONS, LOG_DAEMON);
        signal(SIGHUP, sighandler);
        signal(SIGINT, sighandler);
        signal(SIGTERM, sighandler);
        signal(SIGINFO, sighandler);
        signal(SIGQUIT, sighandler);

        npfd_event_loop(log, delay);

        closelog();

        return 0;
}