/*      $OpenBSD: dvmrpe.c,v 1.30 2024/11/21 13:38:14 claudio Exp $ */

/*
 * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
 * Copyright (c) 2004, 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 <netinet/in.h>
#include <arpa/inet.h>
#include <net/if_types.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <fcntl.h>
#include <pwd.h>
#include <unistd.h>
#include <event.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>

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

void             dvmrpe_sig_handler(int, short, void *);
__dead void      dvmrpe_shutdown(void);

volatile sig_atomic_t    dvmrpe_quit = 0;
struct dvmrpd_conf      *deconf = NULL;
static struct imsgev    *iev_main;
static struct imsgev    *iev_rde;

void
dvmrpe_sig_handler(int sig, short event, void *bula)
{
        switch (sig) {
        case SIGINT:
        case SIGTERM:
                dvmrpe_shutdown();
                /* NOTREACHED */
        default:
                fatalx("unexpected signal");
        }
}

/* dvmrp engine */
pid_t
dvmrpe(struct dvmrpd_conf *xconf, int pipe_parent2dvmrpe[2],
    int pipe_dvmrpe2rde[2], int pipe_parent2rde[2])
{
        struct iface    *iface = NULL;
        struct passwd   *pw;
        struct event     ev_sigint, ev_sigterm;
        pid_t            pid;

        switch (pid = fork()) {
        case -1:
                fatal("cannot fork");
        case 0:
                break;
        default:

                return (pid);
        }

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

        /* create dvmrpd control socket outside chroot */
        if (control_init() == -1)
                fatalx("control socket setup failed");

        /* set some defaults */
        if (if_set_mcast_ttl(xconf->dvmrp_socket,
            IP_DEFAULT_MULTICAST_TTL) == -1)
                fatal("if_set_mcast_ttl");

        if (if_set_mcast_loop(xconf->dvmrp_socket) == -1)
                fatal("if_set_mcast_loop");

        if (if_set_tos(xconf->dvmrp_socket, IPTOS_PREC_INTERNETCONTROL) == -1)
                fatal("if_set_tos");

        if_set_recvbuf(xconf->dvmrp_socket);

        deconf = xconf;

        if ((pw = getpwnam(DVMRPD_USER)) == NULL)
                fatal("getpwnam");

        if (chroot(pw->pw_dir) == -1)
                fatal("chroot");
        if (chdir("/") == -1)
                fatal("chdir(\"/\")");

        setproctitle("dvmrp engine");
        log_procname = "dvmrpe";

        if (setgroups(1, &pw->pw_gid) ||
            setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
            setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
                fatal("can't drop privileges");

        event_init();
        nbr_init(NBR_HASHSIZE);

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

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

        if ((iev_rde = malloc(sizeof(struct imsgev))) == NULL ||
            (iev_main = malloc(sizeof(struct imsgev))) == NULL)
                fatal(NULL);
        if (imsgbuf_init(&iev_rde->ibuf, pipe_dvmrpe2rde[0]) == -1)
                fatal(NULL);
        iev_rde->handler = dvmrpe_dispatch_rde;

        if (imsgbuf_init(&iev_main->ibuf, pipe_parent2dvmrpe[1]) == -1)
                fatal(NULL);
        iev_main->handler = dvmrpe_dispatch_main;

        /* setup event handler */
        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);

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

        event_set(&deconf->ev, deconf->dvmrp_socket, EV_READ|EV_PERSIST,
            recv_packet, deconf);
        event_add(&deconf->ev, NULL);

        /* listen on dvmrpd control socket */
        control_listen();

        /* start interfaces */
        LIST_FOREACH(iface, &deconf->iface_list, entry) {
                if_init(xconf, iface);
                if (if_fsm(iface, IF_EVT_UP)) {
                        log_debug("error starting interface %s", iface->name);
                }
        }

        evtimer_set(&deconf->report_timer, report_timer, deconf);
        start_report_timer();

        event_dispatch();

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

__dead void
dvmrpe_shutdown(void)
{
        struct iface    *iface;

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

        /* stop all interfaces and delete them */
        LIST_FOREACH(iface, &deconf->iface_list, entry) {
                if (if_fsm(iface, IF_EVT_DOWN)) {
                        log_debug("error stopping interface %s",
                            iface->name);
                }
                if_del(iface);
        }

        /* clean up */
        free(iev_rde);
        free(iev_main);

        log_info("dvmrp engine exiting");
        _exit(0);
}

int
dvmrpe_imsg_compose_parent(int type, pid_t pid, void *data, u_int16_t datalen)
{
        return (imsg_compose_event(iev_main, type, 0, pid, -1, data, datalen));
}

int
dvmrpe_imsg_compose_rde(int type, u_int32_t peerid, pid_t pid,
    void *data, u_int16_t datalen)
{
        return (imsg_compose_event(iev_rde, type, peerid, pid,
             -1, data, datalen));
}

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

        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("dvmrpe_dispatch_main: imsg_get error");
                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_IFINFO:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE !=
                            sizeof(struct kif))
                                fatalx("IFINFO imsg with wrong len");
                        kif = imsg.data;
                        link_ok = (kif->flags & IFF_UP) &&
                            LINK_STATE_IS_UP(kif->link_state);

                        LIST_FOREACH(iface, &deconf->iface_list, entry) {
                                if (kif->ifindex == iface->ifindex) {
                                        iface->flags = kif->flags;
                                        iface->linkstate = kif->link_state;

                                        if (link_ok) {
                                                if_fsm(iface, IF_EVT_UP);
                                                log_warnx("interface %s up",
                                                    iface->name);
                                        } else {
                                                if_fsm(iface, IF_EVT_DOWN);
                                                log_warnx("interface %s down",
                                                    iface->name);
                                        }
                                }
                        }
                        break;
                default:
                        log_debug("dvmrpe_dispatch_main: 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
dvmrpe_dispatch_rde(int fd, short event, void *bula)
{
        struct imsgev           *iev = bula;
        struct imsgbuf          *ibuf = &iev->ibuf;
        struct imsg              imsg;
        struct nbr              *nbr;
        struct prune             p;
        struct iface            *iface;
        struct route_report     *rr;
        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("dvmrpe_dispatch_rde: imsgbuf_get error");
                if (n == 0)
                        break;

                switch (imsg.hdr.type) {
                case IMSG_CTL_SHOW_RIB:
                case IMSG_CTL_SHOW_SUM:
                case IMSG_CTL_SHOW_MFC:
                case IMSG_CTL_END:
                        control_imsg_relay(&imsg);
                        break;
                case IMSG_FULL_ROUTE_REPORT:
                        /* add route reports to list */
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(*rr))
                                fatalx("invalid size of RDE request");

                        if ((rr = calloc(1, sizeof(*rr))) == NULL)
                                fatal("dvmrpe_dispatch_rde");

                        memcpy(rr, imsg.data, sizeof(*rr));

                        /* general update, per interface */
                        if (imsg.hdr.peerid == 0) {
                                /* add to interface list */
                                LIST_FOREACH(iface, &deconf->iface_list,
                                    entry) {
                                        if (!if_nbr_list_empty(iface))
                                                rr_list_add(&iface->rr_list,
                                                    rr);
                                }
                                break;
                        }

                        /* add to neighbor list */
                        nbr = nbr_find_peerid(imsg.hdr.peerid);
                        rr_list_add(&nbr->rr_list, rr);
                        break;
                case IMSG_FULL_ROUTE_REPORT_END:
                        /* transmit route report */
                        if (imsg.hdr.peerid == 0) {
                                /*
                                 * send general route report on all
                                 * interfaces with neighbors.
                                 */
                                LIST_FOREACH(iface, &deconf->iface_list,
                                    entry) {
                                        rr_list_send(&iface->rr_list,
                                            iface, NULL);
                                }
                                break;
                        }

                        nbr = nbr_find_peerid(imsg.hdr.peerid);
                        rr_list_send(&nbr->rr_list, NULL, nbr);
                        break;
                case IMSG_SEND_PRUNE:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(p))
                                fatalx("invalid size of RDE request");

                        memcpy(&p, imsg.data, sizeof(p));

                        LIST_FOREACH(iface, &deconf->iface_list, entry)
                                if (p.ifindex == iface->ifindex)
                                        break;

                        if (iface == NULL)
                                fatalx("invalid interface in mfc");

                        nbr = nbr_find_ip(iface, p.nexthop.s_addr);
                        if (nbr == NULL)
                                fatalx("unknown neighbor to send prune");

                        send_prune(nbr, &p);

                        break;
                case IMSG_FLASH_UPDATE:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(*rr))
                                fatalx("invalid size of RDE request");

                        if ((rr = calloc(1, sizeof(*rr))) == NULL)
                                fatal("dvmrpe_dispatch_rde");

                        memcpy(rr, imsg.data, sizeof(*rr));

                        LIST_FOREACH(iface, &deconf->iface_list, entry) {
                                if (!if_nbr_list_empty(iface)) {
                                        rr_list_add(&iface->rr_list, rr);
                                        rr_list_send(&iface->rr_list, iface,
                                            NULL);
                                }
                        }
                        break;
                case IMSG_FLASH_UPDATE_DS:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(*rr))
                                fatalx("invalid size of RDE request");

                        if ((rr = calloc(1, sizeof(*rr))) == NULL)
                                fatal("dvmrpe_dispatch_rde");

                        memcpy(rr, imsg.data, sizeof(*rr));

                        LIST_FOREACH(iface, &deconf->iface_list, entry) {
                                if (iface->ifindex == rr->ifindex)
                                        continue;
                                if (!if_nbr_list_empty(iface)) {
                                        rr_list_add(&iface->rr_list, rr);
                                        rr_list_send(&iface->rr_list, iface,
                                            NULL);
                                }
                        }
                        break;
                default:
                        log_debug("dvmrpe_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
dvmrpe_iface_ctl(struct ctl_conn *c, unsigned int idx)
{
        struct iface            *iface;
        struct ctl_iface        *ictl;

        LIST_FOREACH(iface, &deconf->iface_list, entry)
                if (idx == 0 || idx == iface->ifindex) {
                        ictl = if_to_ctl(iface);
                        imsg_compose_event(&c->iev, IMSG_CTL_SHOW_IFACE,
                            0, 0, -1, ictl, sizeof(struct ctl_iface));
                }
}

void
dvmrpe_iface_igmp_ctl(struct ctl_conn *c, unsigned int idx)
{
        struct iface            *iface;
        struct ctl_iface        *ictl;

        LIST_FOREACH(iface, &deconf->iface_list, entry)
                if (idx == 0 || idx == iface->ifindex) {
                        ictl = if_to_ctl(iface);
                        imsg_compose_event(&c->iev, IMSG_CTL_SHOW_IFACE,
                            0, 0, -1, ictl, sizeof(struct ctl_iface));
                        group_list_dump(iface, c);

                }
}

void
dvmrpe_nbr_ctl(struct ctl_conn *c)
{
        struct iface    *iface;
        struct nbr      *nbr;
        struct ctl_nbr  *nctl;

        LIST_FOREACH(iface, &deconf->iface_list, entry)
                LIST_FOREACH(nbr, &iface->nbr_list, entry) {
                        nctl = nbr_to_ctl(nbr);
                        imsg_compose_event(&c->iev, IMSG_CTL_SHOW_NBR,
                            0, 0, -1, nctl, sizeof(struct ctl_nbr));
                }

        imsg_compose_event(&c->iev, IMSG_CTL_END, 0, 0, -1, NULL, 0);
}