/*      $OpenBSD: dvmrpd.c,v 1.34 2024/11/21 13:38:14 claudio Exp $ */

/*
 * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
 * Copyright (c) 2005, 2006 Esben Norby <norby@openbsd.org>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/queue.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/wait.h>

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

#include <event.h>
#include <err.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <util.h>

#include "igmp.h"
#include "dvmrpd.h"
#include "dvmrp.h"
#include "dvmrpe.h"
#include "control.h"
#include "log.h"
#include "rde.h"

void            main_sig_handler(int, short, void *);
__dead void     usage(void);
__dead void     dvmrpd_shutdown(void);

void    main_dispatch_dvmrpe(int, short, void *);
void    main_dispatch_rde(int, short, void *);
void    main_imsg_compose_dvmrpe(int, pid_t, void *, u_int16_t);
void    main_imsg_compose_rde(int, pid_t, void *, u_int16_t);

int     pipe_parent2dvmrpe[2];
int     pipe_parent2rde[2];
int     pipe_dvmrpe2rde[2];

struct dvmrpd_conf      *conf = NULL;
static struct imsgev    *iev_dvmrpe;
static struct imsgev    *iev_rde;

pid_t                    dvmrpe_pid;
pid_t                    rde_pid;

void
main_sig_handler(int sig, short event, void *arg)
{
        /* signal handler rules don't apply, libevent decouples for us */
        switch (sig) {
        case SIGTERM:
        case SIGINT:
                dvmrpd_shutdown();
                /* NOTREACHED */
        case SIGHUP:
                /* reconfigure */
                /* ... */
                break;
        default:
                fatalx("unexpected signal");
                /* NOTREACHED */
        }
}

__dead void
usage(void)
{
        extern char *__progname;

        fprintf(stderr, "usage: %s [-dnv] [-f file]\n", __progname);
        exit(1);
}

int
main(int argc, char *argv[])
{
        struct event     ev_sigint, ev_sigterm, ev_sighup;
        char            *conffile;
        int              ch, opts = 0;
        int              debug = 0;
        int              ipmforwarding;
        int              mib[4];
        size_t           len;

        conffile = CONF_FILE;
        log_procname = "parent";

        log_init(1);    /* log to stderr until daemonized */
        log_verbose(1);

        while ((ch = getopt(argc, argv, "df:nv")) != -1) {
                switch (ch) {
                case 'd':
                        debug = 1;
                        break;
                case 'f':
                        conffile = optarg;
                        break;
                case 'n':
                        opts |= DVMRPD_OPT_NOACTION;
                        break;
                case 'v':
                        if (opts & DVMRPD_OPT_VERBOSE)
                                opts |= DVMRPD_OPT_VERBOSE2;
                        opts |= DVMRPD_OPT_VERBOSE;
                        log_verbose(1);
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        }

        argc -= optind;
        argv += optind;
        if (argc > 0)
                usage();

        log_init(debug);
        log_verbose(opts & DVMRPD_OPT_VERBOSE);

        /* multicast IP forwarding must be enabled */
        mib[0] = CTL_NET;
        mib[1] = PF_INET;
        mib[2] = IPPROTO_IP;
        mib[3] = IPCTL_MFORWARDING;
        len = sizeof(ipmforwarding);
        if (sysctl(mib, 4, &ipmforwarding, &len, NULL, 0) == -1)
                err(1, "sysctl");

        if (!ipmforwarding)
                errx(1, "multicast IP forwarding not enabled");

        /* fetch interfaces early */
        kif_init();

        /* parse config file */
        if ((conf = parse_config(conffile, opts)) == NULL )
                exit(1);

        if (conf->opts & DVMRPD_OPT_NOACTION) {
                if (conf->opts & DVMRPD_OPT_VERBOSE)
                        print_config(conf);
                else
                        fprintf(stderr, "configuration OK\n");
                exit(0);
        }

        /* check for root privileges  */
        if (geteuid())
                errx(1, "need root privileges");

        /* check for dvmrpd user */
        if (getpwnam(DVMRPD_USER) == NULL)
                errx(1, "unknown user %s", DVMRPD_USER);

        /* start logging */
        log_init(1);

        if (!debug)
                daemon(1, 0);

        log_info("startup");

        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
            PF_UNSPEC, pipe_parent2dvmrpe) == -1)
                fatal("socketpair");
        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
            PF_UNSPEC, pipe_parent2rde) == -1)
                fatal("socketpair");
        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
            PF_UNSPEC, pipe_dvmrpe2rde) == -1)
                fatal("socketpair");

        /* start children */
        rde_pid = rde(conf, pipe_parent2rde, pipe_dvmrpe2rde,
            pipe_parent2dvmrpe);
        dvmrpe_pid = dvmrpe(conf, pipe_parent2dvmrpe, pipe_dvmrpe2rde,
            pipe_parent2rde);

        /* create the raw ip socket */
        if ((conf->mroute_socket = socket(AF_INET,
            SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK,
            IPPROTO_IGMP)) == -1)
                fatal("error creating raw socket");

        if_set_recvbuf(conf->mroute_socket);

        if (mrt_init(conf->mroute_socket))
                fatal("multicast routing not enabled in kernel");

        event_init();

        /* setup signal handler */
        signal_set(&ev_sigint, SIGINT, main_sig_handler, NULL);
        signal_set(&ev_sigterm, SIGTERM, main_sig_handler, NULL);
        signal_set(&ev_sighup, SIGHUP, main_sig_handler, NULL);
        signal_add(&ev_sigint, NULL);
        signal_add(&ev_sigterm, NULL);
        signal_add(&ev_sighup, NULL);
        signal(SIGPIPE, SIG_IGN);

        /* setup pipes to children */
        close(pipe_parent2dvmrpe[1]);
        close(pipe_parent2rde[1]);
        close(pipe_dvmrpe2rde[0]);
        close(pipe_dvmrpe2rde[1]);

        if ((iev_dvmrpe = malloc(sizeof(struct imsgev))) == NULL ||
            (iev_rde = malloc(sizeof(struct imsgev))) == NULL)
                fatal(NULL);
        if (imsgbuf_init(&iev_dvmrpe->ibuf, pipe_parent2dvmrpe[0]) == -1 ||
            imsgbuf_init(&iev_rde->ibuf, pipe_parent2rde[0]) == -1)
                fatal(NULL);
        iev_dvmrpe->handler =  main_dispatch_dvmrpe;
        iev_rde->handler = main_dispatch_rde;

        /* setup event handler */
        iev_dvmrpe->events = EV_READ;
        event_set(&iev_dvmrpe->ev, iev_dvmrpe->ibuf.fd, iev_dvmrpe->events,
            iev_dvmrpe->handler, iev_dvmrpe);
        event_add(&iev_dvmrpe->ev, NULL);

        iev_rde->events = EV_READ;
        event_set(&iev_rde->ev, iev_rde->ibuf.fd, iev_rde->events,
            iev_rde->handler, iev_rde);
        event_add(&iev_rde->ev, NULL);

        if (kmr_init(!(conf->flags & DVMRPD_FLAG_NO_FIB_UPDATE)) == -1)
                dvmrpd_shutdown();
        if (kr_init() == -1)
                dvmrpd_shutdown();

        event_set(&conf->ev, conf->mroute_socket, EV_READ|EV_PERSIST,
            kmr_recv_msg, conf);
        event_add(&conf->ev, NULL);

        event_dispatch();

        dvmrpd_shutdown();
        /* NOTREACHED */
        return (0);
}

__dead void
dvmrpd_shutdown(void)
{
        struct iface    *iface;
        pid_t            pid;
        int              status;

        /* close pipes */
        imsgbuf_clear(&iev_dvmrpe->ibuf);
        close(iev_dvmrpe->ibuf.fd);
        imsgbuf_clear(&iev_rde->ibuf);
        close(iev_rde->ibuf.fd);

        control_cleanup();
        kmr_shutdown();
        kr_shutdown();
        LIST_FOREACH(iface, &conf->iface_list, entry) {
                if_del(iface);
        }
        mrt_done(conf->mroute_socket);

        log_debug("waiting for children to terminate");
        do {
                pid = wait(&status);
                if (pid == -1) {
                        if (errno != EINTR && errno != ECHILD)
                                fatal("wait");
                } else if (WIFSIGNALED(status))
                        log_warnx("%s terminated; signal %d",
                            (pid == rde_pid) ? "route decision engine" :
                            "dvmrp engine", WTERMSIG(status));
        } while (pid != -1 || (pid == -1 && errno == EINTR));

        free(iev_dvmrpe);
        free(iev_rde);

        log_info("terminating");
        exit(0);
}

/* imsg handling */
void
main_dispatch_dvmrpe(int fd, short event, void *bula)
{
        struct imsgev   *iev = bula;
        struct imsgbuf  *ibuf = &iev->ibuf;
        struct imsg      imsg;
        ssize_t          n;
        int              shut = 0, verbose;

        if (event & EV_READ) {
                if ((n = imsgbuf_read(ibuf)) == -1)
                        fatal("imsgbuf_read error");
                if (n == 0)     /* connection closed */
                        shut = 1;
        }
        if (event & EV_WRITE) {
                if (imsgbuf_write(ibuf) == -1) {
                        if (errno == EPIPE)     /* connection closed */
                                shut = 1;
                        else
                                fatal("imsgbuf_write");
                }
        }

        for (;;) {
                if ((n = imsg_get(ibuf, &imsg)) == -1)
                        fatal("imsg_get");

                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_CTL_RELOAD:
                        log_debug("main_dispatch_dvmrpe: IMSG_CTL_RELOAD");
                        /* reconfig */
                        break;
                case IMSG_CTL_MFC_COUPLE:
                        kmr_mfc_couple();
                        break;
                case IMSG_CTL_MFC_DECOUPLE:
                        kmr_mfc_decouple();
                        break;
                case IMSG_CTL_LOG_VERBOSE:
                        /* already checked by dvmrpe */
                        memcpy(&verbose, imsg.data, sizeof(verbose));
                        log_verbose(verbose);
                        break;
                default:
                        log_debug("main_dispatch_dvmrpe: error handling "
                            "imsg %d", imsg.hdr.type);
                        break;
                }
                imsg_free(&imsg);
        }
        if (!shut)
                imsg_event_add(iev);
        else {
                /* this pipe is dead, so remove the event handler */
                event_del(&iev->ev);
                event_loopexit(NULL);
        }
}

void
main_dispatch_rde(int fd, short event, void *bula)
{
        struct mfc       mfc;
        struct imsgev   *iev = bula;
        struct imsgbuf  *ibuf = &iev->ibuf;
        struct imsg      imsg;
        ssize_t          n;
        int              shut = 0;

        if (event & EV_READ) {
                if ((n = imsgbuf_read(ibuf)) == -1)
                        fatal("imsgbuf_read error");
                if (n == 0)     /* connection closed */
                        shut = 1;
        }
        if (event & EV_WRITE) {
                if (imsgbuf_write(ibuf) == -1) {
                        if (errno == EPIPE)     /* connection closed */
                                shut = 1;
                        else
                                fatal("imsgbuf_write");
                }
        }

        for (;;) {
                if ((n = imsg_get(ibuf, &imsg)) == -1)
                        fatal("imsg_get");

                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_MFC_ADD:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(mfc))
                                fatalx("invalid size of RDE request");
                        memcpy(&mfc, imsg.data, sizeof(mfc));

                        /* add to MFC */
                        mrt_add_mfc(conf->mroute_socket, &mfc);
                        break;
                case IMSG_MFC_DEL:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(mfc))
                                fatalx("invalid size of RDE request");
                        memcpy(&mfc, imsg.data, sizeof(mfc));

                        /* remove from MFC */
                        mrt_del_mfc(conf->mroute_socket, &mfc);
                        break;
                default:
                        log_debug("main_dispatch_rde: error handling imsg %d",
                            imsg.hdr.type);
                        break;
                }
                imsg_free(&imsg);
        }
        if (!shut)
                imsg_event_add(iev);
        else {
                /* this pipe is dead, so remove the event handler */
                event_del(&iev->ev);
                event_loopexit(NULL);
        }
}

void
main_imsg_compose_dvmrpe(int type, pid_t pid, void *data, u_int16_t datalen)
{
        imsg_compose_event(iev_dvmrpe, type, 0, pid, -1, data, datalen);
}

void
main_imsg_compose_rde(int type, pid_t pid, void *data, u_int16_t datalen)
{
        imsg_compose_event(iev_rde, type, 0, pid, -1, data, datalen);
}

void
imsg_event_add(struct imsgev *iev)
{
        iev->events = EV_READ;
        if (imsgbuf_queuelen(&iev->ibuf) > 0)
                iev->events |= EV_WRITE;

        event_del(&iev->ev);
        event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev);
        event_add(&iev->ev, NULL);
}

int
imsg_compose_event(struct imsgev *iev, u_int16_t type,
    u_int32_t peerid, pid_t pid, int fd, void *data, u_int16_t datalen)
{
        int     ret;

        if ((ret = imsg_compose(&iev->ibuf, type, peerid,
            pid, fd, data, datalen)) != -1)
                imsg_event_add(iev);
        return (ret);
}