/*      $OpenBSD: ripd.c,v 1.44 2024/11/21 13:38:15 claudio Exp $ */

/*
 * Copyright (c) 2006 Michele Marchetto <mydecay@openbeer.it>
 * Copyright (c) 2005 Claudio Jeker <claudio@openbsd.org>
 * Copyright (c) 2004 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/wait.h>
#include <sys/sysctl.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 "rip.h"
#include "ripd.h"
#include "ripe.h"
#include "log.h"
#include "control.h"
#include "rde.h"

__dead void              usage(void);
void                     main_sig_handler(int, short, void *);
__dead void              ripd_shutdown(void);
void                     main_dispatch_ripe(int, short, void *);
void                     main_dispatch_rde(int, short, void *);

int                      pipe_parent2ripe[2];
int                      pipe_parent2rde[2];
int                      pipe_ripe2rde[2];

struct ripd_conf        *conf = NULL;
static struct imsgev    *iev_ripe;
static struct imsgev    *iev_rde;

pid_t                    ripe_pid = 0;
pid_t                    rde_pid = 0;

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

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

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:
                ripd_shutdown();
                /* NOTREACHED */
        case SIGHUP:
                /* reconfigure */
                /* ... */
                break;
        default:
                fatalx("unexpected signal");
                /* NOTREACHED */
        }
}

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

        conffile = CONF_FILE;
        log_procname = "parent";
        sockname = RIPD_SOCKET;

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

        while ((ch = getopt(argc, argv, "cdD:f:ns:v")) != -1) {
                switch (ch) {
                case 'c':
                        opts |= RIPD_OPT_FORCE_DEMOTE;
                        break;
                case 'd':
                        debug = 1;
                        break;
                case 'D':
                        if (cmdline_symset(optarg) < 0)
                                log_warnx("could not parse macro definition %s",
                                    optarg);
                        break;
                case 'f':
                        conffile = optarg;
                        break;
                case 'n':
                        opts |= RIPD_OPT_NOACTION;
                        break;
                case 's':
                        sockname = optarg;
                        break;
                case 'v':
                        if (opts & RIPD_OPT_VERBOSE)
                                opts |= RIPD_OPT_VERBOSE2;
                        opts |= RIPD_OPT_VERBOSE;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        }

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

        mib[0] = CTL_NET;
        mib[1] = PF_INET;
        mib[2] = IPPROTO_IP;
        mib[3] = IPCTL_FORWARDING;
        len = sizeof(ipforwarding);
        if (sysctl(mib, 4, &ipforwarding, &len, NULL, 0) == -1)
                err(1, "sysctl");

        if (!ipforwarding)
                log_warnx("WARNING: IP forwarding NOT enabled");

        /* fetch interfaces early */
        kif_init();

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

        if (conf->opts & RIPD_OPT_NOACTION) {
                if (conf->opts & RIPD_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 ripd user */
        if (getpwnam(RIPD_USER) == NULL)
                errx(1, "unknown user %s", RIPD_USER);

        log_init(debug);
        log_verbose(conf->opts & RIPD_OPT_VERBOSE);

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

        log_info("startup");

        if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK,
            PF_UNSPEC, pipe_parent2ripe) == -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_ripe2rde) == -1)
                fatal("socketpair");

        /* start children */
        rde_pid = rde(conf, pipe_parent2rde, pipe_ripe2rde, pipe_parent2ripe);
        ripe_pid = ripe(conf, pipe_parent2ripe, pipe_ripe2rde, pipe_parent2rde);

        /* no filesystem visibility */
        if (unveil("/", "") == -1)
                fatal("unveil /");
        if (unveil(NULL, NULL) == -1)
                fatal("unveil");

        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_parent2ripe[1]);
        close(pipe_parent2rde[1]);
        close(pipe_ripe2rde[0]);
        close(pipe_ripe2rde[1]);

        if ((iev_ripe = malloc(sizeof(struct imsgev))) == NULL ||
            (iev_rde = malloc(sizeof(struct imsgev))) == NULL)
                fatal(NULL);
        if (imsgbuf_init(&iev_ripe->ibuf, pipe_parent2ripe[0]) == -1)
                fatal(NULL);
        iev_ripe->handler = main_dispatch_ripe;
        if (imsgbuf_init(&iev_rde->ibuf, pipe_parent2rde[0]) == -1)
                fatal(NULL);
        iev_rde->handler = main_dispatch_rde;

        /* setup event handler */
        iev_ripe->events = EV_READ;
        event_set(&iev_ripe->ev, iev_ripe->ibuf.fd, iev_ripe->events,
            iev_ripe->handler, iev_ripe);
        event_add(&iev_ripe->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 (kr_init(!(conf->flags & RIPD_FLAG_NO_FIB_UPDATE),
            conf->rdomain, conf->fib_priority) == -1)
                fatalx("kr_init failed");

        event_dispatch();

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

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

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

        while ((i = LIST_FIRST(&conf->iface_list)) != NULL) {
                LIST_REMOVE(i, entry);
                if_del(i);
        }

        kr_shutdown();

        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" :
                            "rip engine", WTERMSIG(status));
        } while (pid != -1 || (pid == -1 && errno == EINTR));

        free(iev_ripe);
        free(iev_rde);
        free(conf);

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

/* imsg handling */
void
main_dispatch_ripe(int fd, short event, void *bula)
{
        struct imsgev           *iev = bula;
        struct imsgbuf          *ibuf = &iev->ibuf;
        struct imsg              imsg;
        struct demote_msg        dmsg;
        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:
                        /* XXX reconfig */
                        break;
                case IMSG_CTL_FIB_COUPLE:
                        kr_fib_couple();
                        break;
                case IMSG_CTL_FIB_DECOUPLE:
                        kr_fib_decouple();
                        break;
                case IMSG_CTL_KROUTE:
                case IMSG_CTL_KROUTE_ADDR:
                        kr_show_route(&imsg);
                        break;
                case IMSG_CTL_IFINFO:
                        if (imsg.hdr.len == IMSG_HEADER_SIZE)
                                kr_ifinfo(NULL, imsg.hdr.pid);
                        else if (imsg.hdr.len == IMSG_HEADER_SIZE + IFNAMSIZ)
                                kr_ifinfo(imsg.data, imsg.hdr.pid);
                        else
                                log_warnx("IFINFO request with wrong len");
                        break;
                case IMSG_DEMOTE:
                        if (imsg.hdr.len - IMSG_HEADER_SIZE != sizeof(dmsg))
                                fatalx("invalid size of OE request");
                        memcpy(&dmsg, imsg.data, sizeof(dmsg));
                        carp_demote_set(dmsg.demote_group, dmsg.level);
                        break;
                case IMSG_CTL_LOG_VERBOSE:
                        /* already checked by ripe */
                        memcpy(&verbose, imsg.data, sizeof(verbose));
                        log_verbose(verbose);
                        break;
                default:
                        log_debug("main_dispatch_ripe: 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 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_KROUTE_CHANGE:
                        if (kr_change(imsg.data))
                                log_warn("main_dispatch_rde: error changing "
                                    "route");
                        break;
                case IMSG_KROUTE_DELETE:
                        if (kr_delete(imsg.data))
                                log_warn("main_dispatch_rde: error deleting "
                                    "route");
                        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_ripe(int type, pid_t pid, void *data, u_int16_t datalen)
{
        imsg_compose_event(iev_ripe, 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);
}

int
rip_redistribute(struct kroute *kr)
{
        struct redistribute     *r;
        u_int8_t                 is_default = 0;

        if (kr->flags & F_RIPD_INSERTED)
                return (1);

        /* only allow 0.0.0.0/0 via REDIST_DEFAULT */
        if (kr->prefix.s_addr == INADDR_ANY && kr->netmask.s_addr == INADDR_ANY)
                is_default = 1;

        SIMPLEQ_FOREACH(r, &conf->redist_list, entry) {
                switch (r->type & ~REDIST_NO) {
                case REDIST_LABEL:
                        if (kr->rtlabel == r->label)
                                return (r->type & REDIST_NO ? 0 : 1);
                        break;
                case REDIST_STATIC:
                        /*
                         * Dynamic routes are not redistributable. Placed here
                         * so that link local addresses can be redistributed
                         * via a rtlabel.
                         */
                        if (is_default)
                                continue;
                        if (kr->flags & F_DYNAMIC)
                                continue;
                        if (kr->flags & F_STATIC)
                                return (r->type & REDIST_NO ? 0 : 1);
                        break;
                case REDIST_CONNECTED:
                        if (is_default)
                                continue;
                        if (kr->flags & F_DYNAMIC)
                                continue;
                        if (kr->flags & F_CONNECTED)
                                return (r->type & REDIST_NO ? 0 : 1);
                        break;
                case REDIST_ADDR:
                        if (kr->flags & F_DYNAMIC)
                                continue;

                        if (r->addr.s_addr == INADDR_ANY &&
                            r->mask.s_addr == INADDR_ANY) {
                                if (is_default)
                                        return (r->type & REDIST_NO? 0 : 1);
                                else
                                        return (0);
                        }

                        if ((kr->prefix.s_addr & r->mask.s_addr) ==
                            (r->addr.s_addr & r->mask.s_addr) &&
                            (kr->netmask.s_addr & r->mask.s_addr) ==
                            r->mask.s_addr)
                                return (r->type & REDIST_NO? 0 : 1);
                        break;
                case REDIST_DEFAULT:
                        if (is_default)
                                return (r->type & REDIST_NO? 0 : 1);
                        break;
                }
        }

        return (0);
}

void
imsg_event_add(struct imsgev *iev)
{
        if (iev->handler == NULL) {
                imsgbuf_flush(&iev->ibuf);
                return;
        }

        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);
}