contrib/ntpd/ntp.c

   1 /*      $OpenBSD: src/usr.sbin/ntpd/ntp.c,v 1.44 2004/12/13 12:39:15 dtucker Exp $ */
   2
   3 /*
   4  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
   5  * Copyright (c) 2004 Alexander Guy <alexander.guy@andern.org>
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
  16  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  17  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include <sys/param.h>
  21 #include <sys/time.h>
  22 #include <sys/stat.h>
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <paths.h>
  26 #include <poll.h>
  27 #include <pwd.h>
  28 #include <signal.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <time.h>
  32 #include <unistd.h>
  33
  34 #include "ntpd.h"
  35 #include "ntp.h"
  36
  37 #define PFD_PIPE_MAIN   0
  38 #define PFD_MAX         1
  39
  40 volatile sig_atomic_t    ntp_quit = 0;
  41 struct imsgbuf          *ibuf_main;
  42 struct ntpd_conf        *conf;
  43 u_int                    peer_cnt;
  44
  45 void    ntp_sighdlr(int);
  46 int     ntp_dispatch_imsg(void);
  47 void    peer_add(struct ntp_peer *);
  48 void    peer_remove(struct ntp_peer *);
  49 int     offset_compare(const void *, const void *);
  50
  51 void
  52 ntp_sighdlr(int sig)
  53 {
  54         switch (sig) {
  55         case SIGINT:
  56         case SIGTERM:
  57                 ntp_quit = 1;
  58                 break;
  59         }
  60 }
  61
  62 pid_t
  63 ntp_main(int pipe_prnt[2], struct ntpd_conf *nconf)
  64 {
  65         int                      a, b, nfds, i, j, idx_peers, timeout, nullfd;
  66         u_int                    pfd_elms = 0, idx2peer_elms = 0;
  67         u_int                    listener_cnt, new_cnt;
  68         pid_t                    pid;
  69         struct pollfd           *pfd = NULL;
  70         struct passwd           *pw;
  71         struct servent          *se;
  72         struct listen_addr      *la;
  73         struct ntp_peer         *p;
  74         struct ntp_peer         **idx2peer = NULL;
  75         struct timespec          tp;
  76         struct stat              stb;
  77         time_t                   nextaction;
  78         void                    *newp;
  79
  80         switch (pid = fork()) {
  81         case -1:
  82                 fatal("cannot fork");
  83         case 0:
  84                 break;
  85         default:
  86                 return (pid);
  87         }
  88
  89         if ((se = getservbyname("ntp", "udp")) == NULL)
  90                 fatal("getservbyname");
  91
  92         if ((pw = getpwnam(NTPD_USER)) == NULL)
  93                 fatal(NULL);
  94
  95         if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
  96                 fatal(NULL);
  97
  98         if (stat(pw->pw_dir, &stb) == -1)
  99                 fatal("stat");
 100         if (stb.st_uid != 0 || (stb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
 101                 fatal("bad privsep dir permissions");
 102         if (chroot(pw->pw_dir) == -1)
 103                 fatal("chroot");
 104         if (chdir("/") == -1)
 105                 fatal("chdir(\"/\")");
 106
 107         if (!nconf->debug) {
 108                 dup2(nullfd, STDIN_FILENO);
 109                 dup2(nullfd, STDOUT_FILENO);
 110                 dup2(nullfd, STDERR_FILENO);
 111         }
 112         close(nullfd);
 113
 114         setproctitle("ntp engine");
 115
 116         conf = nconf;
 117         setup_listeners(se, conf, &listener_cnt);
 118
 119         if (setgroups(1, &pw->pw_gid) ||
 120             setegid(pw->pw_gid) || setgid(pw->pw_gid) ||
 121             seteuid(pw->pw_uid) || setuid(pw->pw_uid))
 122                 fatal("can't drop privileges");
 123
 124         endpwent();
 125         endservent();
 126
 127         signal(SIGTERM, ntp_sighdlr);
 128         signal(SIGINT, ntp_sighdlr);
 129         signal(SIGPIPE, SIG_IGN);
 130         signal(SIGHUP, SIG_IGN);
 131
 132         close(pipe_prnt[0]);
 133         if ((ibuf_main = malloc(sizeof(struct imsgbuf))) == NULL)
 134                 fatal(NULL);
 135         imsg_init(ibuf_main, pipe_prnt[1]);
 136
 137         TAILQ_FOREACH(p, &conf->ntp_peers, entry)
 138                 client_peer_init(p);
 139
 140         bzero(&conf->status, sizeof(conf->status));
 141         conf->status.leap = LI_ALARM;
 142         clock_getres(CLOCK_REALTIME, &tp);
 143         b = 1000000000 / tp.tv_nsec;    /* convert to Hz */
 144         for (a = 0; b > 1; a--, b >>= 1);
 145         conf->status.precision = a;
 146
 147
 148         log_info("ntp engine ready");
 149
 150         peer_cnt = 0;
 151         TAILQ_FOREACH(p, &conf->ntp_peers, entry)
 152                 peer_cnt++;
 153
 154         while (ntp_quit == 0) {
 155                 if (peer_cnt > idx2peer_elms) {
 156                         if ((newp = realloc(idx2peer, sizeof(void *) *
 157                             peer_cnt)) == NULL) {
 158                                 /* panic for now */
 159                                 log_warn("could not resize idx2peer from %u -> "
 160                                     "%u entries", idx2peer_elms, peer_cnt);
 161                                 fatalx("exiting");
 162                         }
 163                         idx2peer = newp;
 164                         idx2peer_elms = peer_cnt;
 165                 }
 166
 167                 new_cnt = PFD_MAX + peer_cnt + listener_cnt;
 168                 if (new_cnt > pfd_elms) {
 169                         if ((newp = realloc(pfd, sizeof(struct pollfd) *
 170                             new_cnt)) == NULL) {
 171                                 /* panic for now */
 172                                 log_warn("could not resize pfd from %u -> "
 173                                     "%u entries", pfd_elms, new_cnt);
 174                                 fatalx("exiting");
 175                         }
 176                         pfd = newp;
 177                         pfd_elms = new_cnt;
 178                 }
 179
 180                 bzero(pfd, sizeof(struct pollfd) * pfd_elms);
 181                 bzero(idx2peer, sizeof(void *) * idx2peer_elms);
 182                 nextaction = time(NULL) + 3600;
 183                 pfd[PFD_PIPE_MAIN].fd = ibuf_main->fd;
 184                 pfd[PFD_PIPE_MAIN].events = POLLIN;
 185
 186                 i = 1;
 187                 TAILQ_FOREACH(la, &conf->listen_addrs, entry) {
 188                         pfd[i].fd = la->fd;
 189                         pfd[i].events = POLLIN;
 190                         i++;
 191                 }
 192
 193                 idx_peers = i;
 194                 TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
 195                         if (p->next > 0 && p->next < nextaction)
 196                                 nextaction = p->next;
 197                         if (p->next > 0 && p->next <= time(NULL))
 198                                 client_query(p);
 199
 200                         if (p->deadline > 0 && p->deadline < nextaction)
 201                                 nextaction = p->deadline;
 202                         if (p->deadline > 0 && p->deadline <= time(NULL)) {
 203                                 log_debug("no reply from %s received in time",
 204                                     log_sockaddr(
 205                                     (struct sockaddr *)&p->addr->ss));
 206                                 if (p->trustlevel >= TRUSTLEVEL_BADPEER &&
 207                                     (p->trustlevel /= 2) < TRUSTLEVEL_BADPEER)
 208                                         log_info("peer %s now invalid",
 209                                             log_sockaddr(
 210                                             (struct sockaddr *)&p->addr->ss));
 211                                 client_nextaddr(p);
 212                                 client_query(p);
 213                         }
 214
 215                         if (p->state == STATE_QUERY_SENT) {
 216                                 pfd[i].fd = p->query->fd;
 217                                 pfd[i].events = POLLIN;
 218                                 idx2peer[i - idx_peers] = p;
 219                                 i++;
 220                         }
 221                 }
 222
 223                 if (ibuf_main->w.queued > 0)
 224                         pfd[PFD_PIPE_MAIN].events |= POLLOUT;
 225
 226                 timeout = nextaction - time(NULL);
 227                 if (timeout < 0)
 228                         timeout = 0;
 229
 230                 if ((nfds = poll(pfd, i, timeout * 1000)) == -1)
 231                         if (errno != EINTR) {
 232                                 log_warn("poll error");
 233                                 ntp_quit = 1;
 234                         }
 235
 236                 if (nfds > 0 && (pfd[PFD_PIPE_MAIN].revents & POLLOUT))
 237                         if (msgbuf_write(&ibuf_main->w) < 0) {
 238                                 log_warn("pipe write error (to parent)");
 239                                 ntp_quit = 1;
 240                         }
 241
 242                 if (nfds > 0 && pfd[PFD_PIPE_MAIN].revents & (POLLIN|POLLERR)) {
 243                         nfds--;
 244                         if (ntp_dispatch_imsg() == -1)
 245                                 ntp_quit = 1;
 246                 }
 247
 248                 for (j = 1; nfds > 0 && j < idx_peers; j++)
 249                         if (pfd[j].revents & (POLLIN|POLLERR)) {
 250                                 nfds--;
 251                                 if (server_dispatch(pfd[j].fd, conf) == -1)
 252                                         ntp_quit = 1;
 253                         }
 254
 255                 for (; nfds > 0 && j < i; j++)
 256                         if (pfd[j].revents & (POLLIN|POLLERR)) {
 257                                 nfds--;
 258                                 if (client_dispatch(idx2peer[j - idx_peers],
 259                                     conf->settime) == -1)
 260                                         ntp_quit = 1;
 261                         }
 262         }
 263
 264         msgbuf_write(&ibuf_main->w);
 265         msgbuf_clear(&ibuf_main->w);
 266         free(ibuf_main);
 267
 268         log_info("ntp engine exiting");
 269         _exit(0);
 270 }
 271
 272 int
 273 ntp_dispatch_imsg(void)
 274 {
 275         struct imsg              imsg;
 276         int                      n;
 277         struct ntp_peer         *peer, *npeer;
 278         u_int16_t                dlen;
 279         u_char                  *p;
 280         struct ntp_addr         *h;
 281
 282         if ((n = imsg_read(ibuf_main)) == -1)
 283                 return (-1);
 284
 285         if (n == 0) {   /* connection closed */
 286                 log_warnx("ntp_dispatch_imsg in ntp engine: pipe closed");
 287                 return (-1);
 288         }
 289
 290         for (;;) {
 291                 if ((n = imsg_get(ibuf_main, &imsg)) == -1)
 292                         return (-1);
 293
 294                 if (n == 0)
 295                         break;
 296
 297                 switch (imsg.hdr.type) {
 298                 case IMSG_HOST_DNS:
 299                         TAILQ_FOREACH(peer, &conf->ntp_peers, entry)
 300                                 if (peer->id == imsg.hdr.peerid)
 301                                         break;
 302                         if (peer == NULL) {
 303                                 log_warnx("IMSG_HOST_DNS with invalid peerID");
 304                                 break;
 305                         }
 306                         if (peer->addr != NULL) {
 307                                 log_warnx("IMSG_HOST_DNS but addr != NULL!");
 308                                 break;
 309                         }
 310                         dlen = imsg.hdr.len - IMSG_HEADER_SIZE;
 311                         p = (u_char *)imsg.data;
 312                         while (dlen >= sizeof(struct sockaddr_storage)) {
 313                                 if ((h = calloc(1, sizeof(struct ntp_addr))) ==
 314                                     NULL)
 315                                         fatal(NULL);
 316                                 memcpy(&h->ss, p, sizeof(h->ss));
 317                                 p += sizeof(h->ss);
 318                                 dlen -= sizeof(h->ss);
 319                                 if (peer->addr_head.pool) {
 320                                         npeer = new_peer();
 321                                         h->next = NULL;
 322                                         npeer->addr = h;
 323                                         npeer->addr_head.a = h;
 324                                         client_peer_init(npeer);
 325                                         peer_add(npeer);
 326                                 } else {
 327                                         h->next = peer->addr;
 328                                         peer->addr = h;
 329                                         peer->addr_head.a = peer->addr;
 330                                 }
 331                         }
 332                         if (dlen != 0)
 333                                 fatal("IMSG_HOST_DNS: dlen != 0");
 334                         if (peer->addr_head.pool)
 335                                 peer_remove(peer);
 336                         else
 337                                 client_addr_init(peer);
 338                         break;
 339                 default:
 340                         break;
 341                 }
 342                 imsg_free(&imsg);
 343         }
 344         return (0);
 345 }
 346
 347 void
 348 peer_add(struct ntp_peer *p)
 349 {
 350         TAILQ_INSERT_TAIL(&conf->ntp_peers, p, entry);
 351         peer_cnt++;
 352 }
 353
 354 void
 355 peer_remove(struct ntp_peer *p)
 356 {
 357         TAILQ_REMOVE(&conf->ntp_peers, p, entry);
 358         free(p);
 359         peer_cnt--;
 360 }
 361
 362 void
 363 priv_adjtime(void)
 364 {
 365         struct ntp_peer  *p;
 366         int               offset_cnt = 0, i = 0;
 367         struct ntp_peer **peers;
 368         double            offset_median;
 369
 370         TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
 371                 if (p->trustlevel < TRUSTLEVEL_BADPEER)
 372                         continue;
 373                 if (!p->update.good)
 374                         return;
 375                 offset_cnt++;
 376         }
 377
 378         if ((peers = calloc(offset_cnt, sizeof(struct ntp_peer *))) == NULL)
 379                 fatal("calloc ntp_adjtime");
 380
 381         TAILQ_FOREACH(p, &conf->ntp_peers, entry) {
 382                 if (p->trustlevel < TRUSTLEVEL_BADPEER)
 383                         continue;
 384                 peers[i++] = p;
 385         }
 386
 387         qsort(peers, offset_cnt, sizeof(struct ntp_peer *), offset_compare);
 388
 389         if (offset_cnt > 0) {
 390                 if (offset_cnt > 1 && offset_cnt % 2 == 0) {
 391                         offset_median =
 392                             (peers[offset_cnt / 2 - 1]->update.offset +
 393                             peers[offset_cnt / 2]->update.offset) / 2;
 394                         conf->status.rootdelay =
 395                             (peers[offset_cnt / 2 - 1]->update.delay +
 396                             peers[offset_cnt / 2]->update.delay) / 2;
 397                         conf->status.stratum = MAX(
 398                             peers[offset_cnt / 2 - 1]->update.status.stratum,
 399                             peers[offset_cnt / 2]->update.status.stratum);
 400                 } else {
 401                         offset_median = peers[offset_cnt / 2]->update.offset;
 402                         conf->status.rootdelay =
 403                             peers[offset_cnt / 2]->update.delay;
 404                         conf->status.stratum =
 405                             peers[offset_cnt / 2]->update.status.stratum;
 406                 }
 407
 408                 imsg_compose(ibuf_main, IMSG_ADJTIME, 0, 0,
 409                     &offset_median, sizeof(offset_median));
 410
 411                 conf->status.reftime = gettime();
 412                 conf->status.leap = LI_NOWARNING;
 413                 conf->status.stratum++; /* one more than selected peer */
 414
 415                 if (peers[offset_cnt / 2]->addr->ss.ss_family == AF_INET)
 416                         conf->status.refid = ((struct sockaddr_in *)
 417                             &peers[offset_cnt / 2]->addr->ss)->sin_addr.s_addr;
 418         }
 419
 420         free(peers);
 421
 422         TAILQ_FOREACH(p, &conf->ntp_peers, entry)
 423                 p->update.good = 0;
 424 }
 425
 426 int
 427 offset_compare(const void *aa, const void *bb)
 428 {
 429         const struct ntp_peer * const *a;
 430         const struct ntp_peer * const *b;
 431
 432         a = aa;
 433         b = bb;
 434
 435         if ((*a)->update.offset < (*b)->update.offset)
 436                 return (-1);
 437         else if ((*a)->update.offset > (*b)->update.offset)
 438                 return (1);
 439         else
 440                 return (0);
 441 }
 442
 443 void
 444 priv_settime(double offset)
 445 {
 446         imsg_compose(ibuf_main, IMSG_SETTIME, 0, 0, &offset, sizeof(offset));
 447         conf->settime = 0;
 448 }
 449
 450 void
 451 priv_host_dns(char *name, u_int32_t peerid)
 452 {
 453         u_int16_t       dlen;
 454
 455         dlen = strlen(name) + 1;
 456         imsg_compose(ibuf_main, IMSG_HOST_DNS, peerid, 0, name, dlen);
 457 }