ntp_proto.c revision 358659
1/* 2 * ntp_proto.c - NTP version 4 protocol machinery 3 * 4 * ATTENTION: Get approval from Harlan on all changes to this file! 5 * (Harlan will be discussing these changes with Dave Mills.) 6 * 7 */ 8#ifdef HAVE_CONFIG_H 9#include <config.h> 10#endif 11 12#include "ntpd.h" 13#include "ntp_stdlib.h" 14#include "ntp_unixtime.h" 15#include "ntp_control.h" 16#include "ntp_string.h" 17#include "ntp_leapsec.h" 18#include "ntp_psl.h" 19#include "refidsmear.h" 20#include "lib_strbuf.h" 21 22#include <stdio.h> 23#ifdef HAVE_LIBSCF_H 24#include <libscf.h> 25#endif 26#ifdef HAVE_UNISTD_H 27#include <unistd.h> 28#endif 29 30/* [Bug 3031] define automatic broadcastdelay cutoff preset */ 31#ifndef BDELAY_DEFAULT 32# define BDELAY_DEFAULT (-0.050) 33#endif 34 35#define SRVFUZ_SHIFT 6 /* 64 seconds */ 36#define SRVRSP_FUZZ(x) \ 37 do { \ 38 x.l_uf &= 0; \ 39 x.l_ui &= ~((1 << SRVFUZ_SHIFT) - 1U); \ 40 } while(0) 41 42/* 43 * This macro defines the authentication state. If x is 1 authentication 44 * is required; otherwise it is optional. 45 */ 46#define AUTH(x, y) ((x) ? (y) == AUTH_OK \ 47 : (y) == AUTH_OK || (y) == AUTH_NONE) 48 49typedef enum 50auth_state { 51 AUTH_UNKNOWN = -1, /* Unknown */ 52 AUTH_NONE, /* authentication not required */ 53 AUTH_OK, /* authentication OK */ 54 AUTH_ERROR, /* authentication error */ 55 AUTH_CRYPTO /* crypto_NAK */ 56} auth_code; 57 58/* 59 * Set up Kiss Code values 60 */ 61 62typedef enum 63kiss_codes { 64 NOKISS, /* No Kiss Code */ 65 RATEKISS, /* Rate limit Kiss Code */ 66 DENYKISS, /* Deny Kiss */ 67 RSTRKISS, /* Restricted Kiss */ 68 XKISS /* Experimental Kiss */ 69} kiss_code; 70 71typedef enum 72nak_error_codes { 73 NONAK, /* No NAK seen */ 74 INVALIDNAK, /* NAK cannot be used */ 75 VALIDNAK /* NAK is valid */ 76} nak_code; 77 78/* 79 * traffic shaping parameters 80 */ 81#define NTP_IBURST 6 /* packets in iburst */ 82#define RESP_DELAY 1 /* refclock burst delay (s) */ 83 84/* 85 * pool soliciting restriction duration (s) 86 */ 87#define POOL_SOLICIT_WINDOW 8 88 89/* 90 * flag bits propagated from pool to individual peers 91 */ 92#define POOL_FLAG_PMASK (FLAG_IBURST | FLAG_NOSELECT) 93 94/* 95 * peer_select groups statistics for a peer used by clock_select() and 96 * clock_cluster(). 97 */ 98typedef struct peer_select_tag { 99 struct peer * peer; 100 double synch; /* sync distance */ 101 double error; /* jitter */ 102 double seljit; /* selection jitter */ 103} peer_select; 104 105/* 106 * System variables are declared here. Unless specified otherwise, all 107 * times are in seconds. 108 */ 109u_char sys_leap; /* system leap indicator, use set_sys_leap() to change this */ 110u_char xmt_leap; /* leap indicator sent in client requests, set up by set_sys_leap() */ 111u_char sys_stratum; /* system stratum */ 112s_char sys_precision; /* local clock precision (log2 s) */ 113double sys_rootdelay; /* roundtrip delay to root (primary source) */ 114double sys_rootdisp; /* dispersion to root (primary source) */ 115double prev_rootdisp; /* previous root dispersion */ 116double p2_rootdisp; /* previous previous root dispersion */ 117u_int32 sys_refid; /* reference id (network byte order) */ 118l_fp sys_reftime; /* last update time */ 119l_fp prev_reftime; /* previous sys_reftime */ 120l_fp p2_reftime; /* previous previous sys_reftime */ 121u_long prev_time; /* "current_time" when saved prev_time */ 122u_long p2_time; /* previous prev_time */ 123struct peer *sys_peer; /* current peer */ 124 125#ifdef LEAP_SMEAR 126struct leap_smear_info leap_smear; 127#endif 128int leap_sec_in_progress; 129 130/* 131 * Rate controls. Leaky buckets are used to throttle the packet 132 * transmission rates in order to protect busy servers such as at NIST 133 * and USNO. There is a counter for each association and another for KoD 134 * packets. The association counter decrements each second, but not 135 * below zero. Each time a packet is sent the counter is incremented by 136 * a configurable value representing the average interval between 137 * packets. A packet is delayed as long as the counter is greater than 138 * zero. Note this does not affect the time value computations. 139 */ 140/* 141 * Nonspecified system state variables 142 */ 143int sys_bclient; /* broadcast client enable */ 144double sys_bdelay; /* broadcast client default delay */ 145int sys_authenticate; /* requre authentication for config */ 146l_fp sys_authdelay; /* authentication delay */ 147double sys_offset; /* current local clock offset */ 148double sys_mindisp = MINDISPERSE; /* minimum distance (s) */ 149double sys_maxdist = MAXDISTANCE; /* selection threshold */ 150double sys_jitter; /* system jitter */ 151u_long sys_epoch; /* last clock update time */ 152static double sys_clockhop; /* clockhop threshold */ 153static int leap_vote_ins; /* leap consensus for insert */ 154static int leap_vote_del; /* leap consensus for delete */ 155keyid_t sys_private; /* private value for session seed */ 156int sys_manycastserver; /* respond to manycast client pkts */ 157int ntp_mode7; /* respond to ntpdc (mode7) */ 158int peer_ntpdate; /* active peers in ntpdate mode */ 159int sys_survivors; /* truest of the truechimers */ 160char *sys_ident = NULL; /* identity scheme */ 161 162/* 163 * TOS and multicast mapping stuff 164 */ 165int sys_floor = 0; /* cluster stratum floor */ 166u_char sys_bcpollbstep = 0; /* Broadcast Poll backstep gate */ 167int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */ 168int sys_minsane = 1; /* minimum candidates */ 169int sys_minclock = NTP_MINCLOCK; /* minimum candidates */ 170int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */ 171int sys_cohort = 0; /* cohort switch */ 172int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */ 173int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */ 174int sys_beacon = BEACON; /* manycast beacon interval */ 175u_int sys_ttlmax; /* max ttl mapping vector index */ 176u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */ 177 178/* 179 * Statistics counters - first the good, then the bad 180 */ 181u_long sys_stattime; /* elapsed time */ 182u_long sys_received; /* packets received */ 183u_long sys_processed; /* packets for this host */ 184u_long sys_newversion; /* current version */ 185u_long sys_oldversion; /* old version */ 186u_long sys_restricted; /* access denied */ 187u_long sys_badlength; /* bad length or format */ 188u_long sys_badauth; /* bad authentication */ 189u_long sys_declined; /* declined */ 190u_long sys_limitrejected; /* rate exceeded */ 191u_long sys_kodsent; /* KoD sent */ 192 193/* 194 * Mechanism knobs: how soon do we peer_clear() or unpeer()? 195 * 196 * The default way is "on-receipt". If this was a packet from a 197 * well-behaved source, on-receipt will offer the fastest recovery. 198 * If this was from a DoS attack, the default way makes it easier 199 * for a bad-guy to DoS us. So look and see what bites you harder 200 * and choose according to your environment. 201 */ 202int peer_clear_digest_early = 1; /* bad digest (TEST5) and Autokey */ 203int unpeer_crypto_early = 1; /* bad crypto (TEST9) */ 204int unpeer_crypto_nak_early = 1; /* crypto_NAK (TEST5) */ 205int unpeer_digest_early = 1; /* bad digest (TEST5) */ 206 207int dynamic_interleave = DYNAMIC_INTERLEAVE; /* Bug 2978 mitigation */ 208 209int kiss_code_check(u_char hisleap, u_char hisstratum, u_char hismode, u_int32 refid); 210nak_code valid_NAK (struct peer *peer, struct recvbuf *rbufp, u_char hismode); 211static double root_distance (struct peer *); 212static void clock_combine (peer_select *, int, int); 213static void peer_xmit (struct peer *); 214static void fast_xmit (struct recvbuf *, int, keyid_t, int); 215static void pool_xmit (struct peer *); 216static void clock_update (struct peer *); 217static void measure_precision(void); 218static double measure_tick_fuzz(void); 219static int local_refid (struct peer *); 220static int peer_unfit (struct peer *); 221#ifdef AUTOKEY 222static int group_test (char *, char *); 223#endif /* AUTOKEY */ 224#ifdef WORKER 225void pool_name_resolved (int, int, void *, const char *, 226 const char *, const struct addrinfo *, 227 const struct addrinfo *); 228#endif /* WORKER */ 229 230const char * amtoa (int am); 231 232 233void 234set_sys_leap( 235 u_char new_sys_leap 236 ) 237{ 238 sys_leap = new_sys_leap; 239 xmt_leap = sys_leap; 240 241 /* 242 * Under certain conditions we send faked leap bits to clients, so 243 * eventually change xmt_leap below, but never change LEAP_NOTINSYNC. 244 */ 245 if (xmt_leap != LEAP_NOTINSYNC) { 246 if (leap_sec_in_progress) { 247 /* always send "not sync" */ 248 xmt_leap = LEAP_NOTINSYNC; 249 } 250#ifdef LEAP_SMEAR 251 else { 252 /* 253 * If leap smear is enabled in general we must 254 * never send a leap second warning to clients, 255 * so make sure we only send "in sync". 256 */ 257 if (leap_smear.enabled) 258 xmt_leap = LEAP_NOWARNING; 259 } 260#endif /* LEAP_SMEAR */ 261 } 262} 263 264 265/* 266 * Kiss Code check 267 */ 268int 269kiss_code_check( 270 u_char hisleap, 271 u_char hisstratum, 272 u_char hismode, 273 u_int32 refid 274 ) 275{ 276 277 if ( hismode == MODE_SERVER 278 && hisleap == LEAP_NOTINSYNC 279 && hisstratum == STRATUM_UNSPEC) { 280 if(memcmp(&refid,"RATE", 4) == 0) { 281 return (RATEKISS); 282 } else if(memcmp(&refid,"DENY", 4) == 0) { 283 return (DENYKISS); 284 } else if(memcmp(&refid,"RSTR", 4) == 0) { 285 return (RSTRKISS); 286 } else if(memcmp(&refid,"X", 1) == 0) { 287 return (XKISS); 288 } 289 } 290 return (NOKISS); 291} 292 293 294/* 295 * Check that NAK is valid 296 */ 297nak_code 298valid_NAK( 299 struct peer *peer, 300 struct recvbuf *rbufp, 301 u_char hismode 302 ) 303{ 304 int base_packet_length = MIN_V4_PKT_LEN; 305 int remainder_size; 306 struct pkt * rpkt; 307 int keyid; 308 l_fp p_org; /* origin timestamp */ 309 const l_fp * myorg; /* selected peer origin */ 310 311 /* 312 * Check to see if there is something beyond the basic packet 313 */ 314 if (rbufp->recv_length == base_packet_length) { 315 return NONAK; 316 } 317 318 remainder_size = rbufp->recv_length - base_packet_length; 319 /* 320 * Is this a potential NAK? 321 */ 322 if (remainder_size != 4) { 323 return NONAK; 324 } 325 326 /* 327 * Only server responses can contain NAK's 328 */ 329 330 if (hismode != MODE_SERVER && 331 hismode != MODE_ACTIVE && 332 hismode != MODE_PASSIVE 333 ) { 334 return INVALIDNAK; 335 } 336 337 /* 338 * Make sure that the extra field in the packet is all zeros 339 */ 340 rpkt = &rbufp->recv_pkt; 341 keyid = ntohl(((u_int32 *)rpkt)[base_packet_length / 4]); 342 if (keyid != 0) { 343 return INVALIDNAK; 344 } 345 346 /* 347 * During the first few packets of the autokey dance there will 348 * not (yet) be a keyid, but in this case FLAG_SKEY is set. 349 * So the NAK is invalid if either there's no peer, or 350 * if the keyid is 0 and FLAG_SKEY is not set. 351 */ 352 if (!peer || (!peer->keyid && !(peer->flags & FLAG_SKEY))) { 353 return INVALIDNAK; 354 } 355 356 /* 357 * The ORIGIN must match, or this cannot be a valid NAK, either. 358 */ 359 360 if (FLAG_LOOPNONCE & peer->flags) { 361 myorg = &peer->nonce; 362 } else { 363 if (peer->flip > 0) { 364 myorg = &peer->borg; 365 } else { 366 myorg = &peer->aorg; 367 } 368 } 369 370 NTOHL_FP(&rpkt->org, &p_org); 371 372 if (L_ISZERO(&p_org) || 373 L_ISZERO( myorg) || 374 !L_ISEQU(&p_org, myorg)) { 375 return INVALIDNAK; 376 } 377 378 /* If we ever passed all that checks, we should be safe. Well, 379 * as safe as we can ever be with an unauthenticated crypto-nak. 380 */ 381 return VALIDNAK; 382} 383 384 385/* 386 * transmit - transmit procedure called by poll timeout 387 */ 388void 389transmit( 390 struct peer *peer /* peer structure pointer */ 391 ) 392{ 393 u_char hpoll; 394 395 /* 396 * The polling state machine. There are two kinds of machines, 397 * those that never expect a reply (broadcast and manycast 398 * server modes) and those that do (all other modes). The dance 399 * is intricate... 400 */ 401 hpoll = peer->hpoll; 402 403 /* 404 * If we haven't received anything (even if unsync) since last 405 * send, reset ppoll. 406 */ 407 if (peer->outdate > peer->timelastrec && !peer->reach) 408 peer->ppoll = peer->maxpoll; 409 410 /* 411 * In broadcast mode the poll interval is never changed from 412 * minpoll. 413 */ 414 if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) { 415 peer->outdate = current_time; 416 poll_update(peer, hpoll, 0); 417 if (sys_leap != LEAP_NOTINSYNC) 418 peer_xmit(peer); 419 return; 420 } 421 422 /* 423 * In manycast mode we start with unity ttl. The ttl is 424 * increased by one for each poll until either sys_maxclock 425 * servers have been found or the maximum ttl is reached. When 426 * sys_maxclock servers are found we stop polling until one or 427 * more servers have timed out or until less than sys_minclock 428 * associations turn up. In this case additional better servers 429 * are dragged in and preempt the existing ones. Once every 430 * sys_beacon seconds we are to transmit unconditionally, but 431 * this code is not quite right -- peer->unreach counts polls 432 * and is being compared with sys_beacon, so the beacons happen 433 * every sys_beacon polls. 434 */ 435 if (peer->cast_flags & MDF_ACAST) { 436 peer->outdate = current_time; 437 poll_update(peer, hpoll, 0); 438 if (peer->unreach > sys_beacon) { 439 peer->unreach = 0; 440 peer->ttl = 0; 441 peer_xmit(peer); 442 } else if ( sys_survivors < sys_minclock 443 || peer_associations < sys_maxclock) { 444 if (peer->ttl < sys_ttlmax) 445 peer->ttl++; 446 peer_xmit(peer); 447 } 448 peer->unreach++; 449 return; 450 } 451 452 /* 453 * Pool associations transmit unicast solicitations when there 454 * are less than a hard limit of 2 * sys_maxclock associations, 455 * and either less than sys_minclock survivors or less than 456 * sys_maxclock associations. The hard limit prevents unbounded 457 * growth in associations if the system clock or network quality 458 * result in survivor count dipping below sys_minclock often. 459 * This was observed testing with pool, where sys_maxclock == 12 460 * resulted in 60 associations without the hard limit. A 461 * similar hard limit on manycastclient ephemeral associations 462 * may be appropriate. 463 */ 464 if (peer->cast_flags & MDF_POOL) { 465 peer->outdate = current_time; 466 poll_update(peer, hpoll, 0); 467 if ( (peer_associations <= 2 * sys_maxclock) 468 && ( peer_associations < sys_maxclock 469 || sys_survivors < sys_minclock)) 470 pool_xmit(peer); 471 return; 472 } 473 474 /* 475 * In unicast modes the dance is much more intricate. It is 476 * designed to back off whenever possible to minimize network 477 * traffic. 478 */ 479 if (peer->burst == 0) { 480 u_char oreach; 481 482 /* 483 * Update the reachability status. If not heard for 484 * three consecutive polls, stuff infinity in the clock 485 * filter. 486 */ 487 oreach = peer->reach; 488 peer->outdate = current_time; 489 peer->unreach++; 490 peer->reach <<= 1; 491 if (!peer->reach) { 492 493 /* 494 * Here the peer is unreachable. If it was 495 * previously reachable raise a trap. Send a 496 * burst if enabled. 497 */ 498 clock_filter(peer, 0., 0., MAXDISPERSE); 499 if (oreach) { 500 peer_unfit(peer); 501 report_event(PEVNT_UNREACH, peer, NULL); 502 } 503 if ( (peer->flags & FLAG_IBURST) 504 && peer->retry == 0) 505 peer->retry = NTP_RETRY; 506 } else { 507 508 /* 509 * Here the peer is reachable. Send a burst if 510 * enabled and the peer is fit. Reset unreach 511 * for persistent and ephemeral associations. 512 * Unreach is also reset for survivors in 513 * clock_select(). 514 */ 515 hpoll = sys_poll; 516 if (!(peer->flags & FLAG_PREEMPT)) 517 peer->unreach = 0; 518 if ( (peer->flags & FLAG_BURST) 519 && peer->retry == 0 520 && !peer_unfit(peer)) 521 peer->retry = NTP_RETRY; 522 } 523 524 /* 525 * Watch for timeout. If ephemeral, toss the rascal; 526 * otherwise, bump the poll interval. Note the 527 * poll_update() routine will clamp it to maxpoll. 528 * If preemptible and we have more peers than maxclock, 529 * and this peer has the minimum score of preemptibles, 530 * demobilize. 531 */ 532 if (peer->unreach >= NTP_UNREACH) { 533 hpoll++; 534 /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */ 535 if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) { 536 report_event(PEVNT_RESTART, peer, "timeout"); 537 peer_clear(peer, "TIME"); 538 unpeer(peer); 539 return; 540 } 541 if ( (peer->flags & FLAG_PREEMPT) 542 && (peer_associations > sys_maxclock) 543 && score_all(peer)) { 544 report_event(PEVNT_RESTART, peer, "timeout"); 545 peer_clear(peer, "TIME"); 546 unpeer(peer); 547 return; 548 } 549 } 550 } else { 551 peer->burst--; 552 if (peer->burst == 0) { 553 554 /* 555 * If ntpdate mode and the clock has not been 556 * set and all peers have completed the burst, 557 * we declare a successful failure. 558 */ 559 if (mode_ntpdate) { 560 peer_ntpdate--; 561 if (peer_ntpdate == 0) { 562 msyslog(LOG_NOTICE, 563 "ntpd: no servers found"); 564 if (!msyslog_term) 565 printf( 566 "ntpd: no servers found\n"); 567 exit (0); 568 } 569 } 570 } 571 } 572 if (peer->retry > 0) 573 peer->retry--; 574 575 /* 576 * Do not transmit if in broadcast client mode. 577 */ 578 poll_update(peer, hpoll, (peer->hmode == MODE_CLIENT)); 579 if (peer->hmode != MODE_BCLIENT) 580 peer_xmit(peer); 581 582 return; 583} 584 585 586const char * 587amtoa( 588 int am 589 ) 590{ 591 char *bp; 592 593 switch(am) { 594 case AM_ERR: return "AM_ERR"; 595 case AM_NOMATCH: return "AM_NOMATCH"; 596 case AM_PROCPKT: return "AM_PROCPKT"; 597 case AM_BCST: return "AM_BCST"; 598 case AM_FXMIT: return "AM_FXMIT"; 599 case AM_MANYCAST: return "AM_MANYCAST"; 600 case AM_NEWPASS: return "AM_NEWPASS"; 601 case AM_NEWBCL: return "AM_NEWBCL"; 602 case AM_POSSBCL: return "AM_POSSBCL"; 603 default: 604 LIB_GETBUF(bp); 605 snprintf(bp, LIB_BUFLENGTH, "AM_#%d", am); 606 return bp; 607 } 608} 609 610 611/* 612 * receive - receive procedure called for each packet received 613 */ 614void 615receive( 616 struct recvbuf *rbufp 617 ) 618{ 619 register struct peer *peer; /* peer structure pointer */ 620 register struct pkt *pkt; /* receive packet pointer */ 621 u_char hisversion; /* packet version */ 622 u_char hisleap; /* packet leap indicator */ 623 u_char hismode; /* packet mode */ 624 u_char hisstratum; /* packet stratum */ 625 r4addr r4a; /* address restrictions */ 626 u_short restrict_mask; /* restrict bits */ 627 const char *hm_str; /* hismode string */ 628 const char *am_str; /* association match string */ 629 int kissCode = NOKISS; /* Kiss Code */ 630 int has_mac; /* length of MAC field */ 631 int authlen; /* offset of MAC field */ 632 auth_code is_authentic = AUTH_UNKNOWN; /* Was AUTH_NONE */ 633 nak_code crypto_nak_test; /* result of crypto-NAK check */ 634 int retcode = AM_NOMATCH; /* match code */ 635 keyid_t skeyid = 0; /* key IDs */ 636 u_int32 opcode = 0; /* extension field opcode */ 637 sockaddr_u *dstadr_sin; /* active runway */ 638 struct peer *peer2; /* aux peer structure pointer */ 639 endpt *match_ep; /* newpeer() local address */ 640 l_fp p_org; /* origin timestamp */ 641 l_fp p_rec; /* receive timestamp */ 642 l_fp p_xmt; /* transmit timestamp */ 643#ifdef AUTOKEY 644 char hostname[NTP_MAXSTRLEN + 1]; 645 char *groupname = NULL; 646 struct autokey *ap; /* autokey structure pointer */ 647 int rval; /* cookie snatcher */ 648 keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */ 649#endif /* AUTOKEY */ 650#ifdef HAVE_NTP_SIGND 651 static unsigned char zero_key[16]; 652#endif /* HAVE_NTP_SIGND */ 653 654 /* 655 * Note that there are many places we do not call record_raw_stats(). 656 * 657 * We only want to call it *after* we've sent a response, or perhaps 658 * when we've decided to drop a packet. 659 */ 660 661 /* 662 * Monitor the packet and get restrictions. Note that the packet 663 * length for control and private mode packets must be checked 664 * by the service routines. Some restrictions have to be handled 665 * later in order to generate a kiss-o'-death packet. 666 */ 667 /* 668 * Bogus port check is before anything, since it probably 669 * reveals a clogging attack. Likewise the mimimum packet size 670 * of 2 bytes (for mode 6/7) must be checked first. 671 */ 672 sys_received++; 673 if (0 == SRCPORT(&rbufp->recv_srcadr) || rbufp->recv_length < 2) { 674 sys_badlength++; 675 return; /* bogus port / length */ 676 } 677 restrictions(&rbufp->recv_srcadr, &r4a); 678 restrict_mask = r4a.rflags; 679 680 pkt = &rbufp->recv_pkt; 681 hisversion = PKT_VERSION(pkt->li_vn_mode); 682 hismode = (int)PKT_MODE(pkt->li_vn_mode); 683 684 if (restrict_mask & RES_IGNORE) { 685 DPRINTF(2, ("receive: drop: RES_IGNORE\n")); 686 sys_restricted++; 687 return; /* ignore everything */ 688 } 689 if (hismode == MODE_PRIVATE) { 690 if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) { 691 DPRINTF(2, ("receive: drop: RES_NOQUERY\n")); 692 sys_restricted++; 693 return; /* no query private */ 694 } 695 process_private(rbufp, ((restrict_mask & 696 RES_NOMODIFY) == 0)); 697 return; 698 } 699 if (hismode == MODE_CONTROL) { 700 if (restrict_mask & RES_NOQUERY) { 701 DPRINTF(2, ("receive: drop: RES_NOQUERY\n")); 702 sys_restricted++; 703 return; /* no query control */ 704 } 705 process_control(rbufp, restrict_mask); 706 return; 707 } 708 if (restrict_mask & RES_DONTSERVE) { 709 DPRINTF(2, ("receive: drop: RES_DONTSERVE\n")); 710 sys_restricted++; 711 return; /* no time serve */ 712 } 713 714 715 /* If we arrive here, we should have a standard NTP packet. We 716 * check that the minimum size is available and fetch some more 717 * items from the packet once we can be sure they are indeed 718 * there. 719 */ 720 if (rbufp->recv_length < LEN_PKT_NOMAC) { 721 sys_badlength++; 722 return; /* bogus length */ 723 } 724 725 hisleap = PKT_LEAP(pkt->li_vn_mode); 726 hisstratum = PKT_TO_STRATUM(pkt->stratum); 727 INSIST(0 != hisstratum); /* paranoia check PKT_TO_STRATUM result */ 728 729 DPRINTF(1, ("receive: at %ld %s<-%s ippeerlimit %d mode %d iflags %s " 730 "restrict %s org %#010x.%08x xmt %#010x.%08x\n", 731 current_time, stoa(&rbufp->dstadr->sin), 732 stoa(&rbufp->recv_srcadr), r4a.ippeerlimit, hismode, 733 build_iflags(rbufp->dstadr->flags), 734 build_rflags(restrict_mask), 735 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 736 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 737 738 /* 739 * This is for testing. If restricted drop ten percent of 740 * surviving packets. 741 */ 742 if (restrict_mask & RES_FLAKE) { 743 if ((double)ntp_random() / 0x7fffffff < .1) { 744 DPRINTF(2, ("receive: drop: RES_FLAKE\n")); 745 sys_restricted++; 746 return; /* no flakeway */ 747 } 748 } 749 750 /* 751 ** Format Layer Checks 752 ** 753 ** Validate the packet format. The packet size, packet header, 754 ** and any extension field lengths are checked. We identify 755 ** the beginning of the MAC, to identify the upper limit of 756 ** of the hash computation. 757 ** 758 ** In case of a format layer check violation, the packet is 759 ** discarded with no further processing. 760 */ 761 762 /* 763 * Version check must be after the query packets, since they 764 * intentionally use an early version. 765 */ 766 if (hisversion == NTP_VERSION) { 767 sys_newversion++; /* new version */ 768 } else if ( !(restrict_mask & RES_VERSION) 769 && hisversion >= NTP_OLDVERSION) { 770 sys_oldversion++; /* previous version */ 771 } else { 772 DPRINTF(2, ("receive: drop: RES_VERSION\n")); 773 sys_badlength++; 774 return; /* old version */ 775 } 776 777 /* 778 * Figure out his mode and validate the packet. This has some 779 * legacy raunch that probably should be removed. In very early 780 * NTP versions mode 0 was equivalent to what later versions 781 * would interpret as client mode. 782 */ 783 if (hismode == MODE_UNSPEC) { 784 if (hisversion == NTP_OLDVERSION) { 785 hismode = MODE_CLIENT; 786 } else { 787 DPRINTF(2, ("receive: drop: MODE_UNSPEC\n")); 788 sys_badlength++; 789 return; /* invalid mode */ 790 } 791 } 792 793 /* 794 * Parse the extension field if present. We figure out whether 795 * an extension field is present by measuring the MAC size. If 796 * the number of words following the packet header is 0, no MAC 797 * is present and the packet is not authenticated. If 1, the 798 * packet is a crypto-NAK; if 3, the packet is authenticated 799 * with DES; if 5, the packet is authenticated with MD5; if 6, 800 * the packet is authenticated with SHA. If 2 or * 4, the packet 801 * is a runt and discarded forthwith. If greater than 6, an 802 * extension field is present, so we subtract the length of the 803 * field and go around again. 804 * 805 * Note the above description is lame. We should/could also check 806 * the two bytes that make up the EF type and subtype, and then 807 * check the two bytes that tell us the EF length. A legacy MAC 808 * has a 4 byte keyID, and for conforming symmetric keys its value 809 * must be <= 64k, meaning the top two bytes will always be zero. 810 * Since the EF Type of 0 is reserved/unused, there's no way a 811 * conforming legacy MAC could ever be misinterpreted as an EF. 812 * 813 * There is more, but this isn't the place to document it. 814 */ 815 816 authlen = LEN_PKT_NOMAC; 817 has_mac = rbufp->recv_length - authlen; 818 while (has_mac > 0) { 819 u_int32 len; 820#ifdef AUTOKEY 821 u_int32 hostlen; 822 struct exten *ep; 823#endif /*AUTOKEY */ 824 825 if (has_mac % 4 != 0 || has_mac < (int)MIN_MAC_LEN) { 826 DPRINTF(2, ("receive: drop: bad post-packet length\n")); 827 sys_badlength++; 828 return; /* bad length */ 829 } 830 /* 831 * This next test is clearly wrong - it needlessly 832 * prohibits short EFs (which don't yet exist) 833 */ 834 if (has_mac <= (int)MAX_MAC_LEN) { 835 skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]); 836 break; 837 838 } else { 839 opcode = ntohl(((u_int32 *)pkt)[authlen / 4]); 840 len = opcode & 0xffff; 841 if ( len % 4 != 0 842 || len < 4 843 || (int)len + authlen > rbufp->recv_length) { 844 DPRINTF(2, ("receive: drop: bad EF length\n")); 845 sys_badlength++; 846 return; /* bad length */ 847 } 848#ifdef AUTOKEY 849 /* 850 * Extract calling group name for later. If 851 * sys_groupname is non-NULL, there must be 852 * a group name provided to elicit a response. 853 */ 854 if ( (opcode & 0x3fff0000) == CRYPTO_ASSOC 855 && sys_groupname != NULL) { 856 ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4]; 857 hostlen = ntohl(ep->vallen); 858 if ( hostlen >= sizeof(hostname) 859 || hostlen > len - 860 offsetof(struct exten, pkt)) { 861 DPRINTF(2, ("receive: drop: bad autokey hostname length\n")); 862 sys_badlength++; 863 return; /* bad length */ 864 } 865 memcpy(hostname, &ep->pkt, hostlen); 866 hostname[hostlen] = '\0'; 867 groupname = strchr(hostname, '@'); 868 if (groupname == NULL) { 869 DPRINTF(2, ("receive: drop: empty autokey groupname\n")); 870 sys_declined++; 871 return; 872 } 873 groupname++; 874 } 875#endif /* AUTOKEY */ 876 authlen += len; 877 has_mac -= len; 878 } 879 } 880 881 /* 882 * If has_mac is < 0 we had a malformed packet. 883 */ 884 if (has_mac < 0) { 885 DPRINTF(2, ("receive: drop: post-packet under-read\n")); 886 sys_badlength++; 887 return; /* bad length */ 888 } 889 890 /* 891 ** Packet Data Verification Layer 892 ** 893 ** This layer verifies the packet data content. If 894 ** authentication is required, a MAC must be present. 895 ** If a MAC is present, it must validate. 896 ** Crypto-NAK? Look - a shiny thing! 897 ** 898 ** If authentication fails, we're done. 899 */ 900 901 /* 902 * If authentication is explicitly required, a MAC must be present. 903 */ 904 if (restrict_mask & RES_DONTTRUST && has_mac == 0) { 905 DPRINTF(2, ("receive: drop: RES_DONTTRUST\n")); 906 sys_restricted++; 907 return; /* access denied */ 908 } 909 910 /* 911 * Update the MRU list and finger the cloggers. It can be a 912 * little expensive, so turn it off for production use. 913 * RES_LIMITED and RES_KOD will be cleared in the returned 914 * restrict_mask unless one or both actions are warranted. 915 */ 916 restrict_mask = ntp_monitor(rbufp, restrict_mask); 917 if (restrict_mask & RES_LIMITED) { 918 sys_limitrejected++; 919 if ( !(restrict_mask & RES_KOD) 920 || MODE_BROADCAST == hismode 921 || MODE_SERVER == hismode) { 922 if (MODE_SERVER == hismode) { 923 DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n", 924 stoa(&rbufp->recv_srcadr))); 925 } else { 926 DPRINTF(2, ("receive: drop: RES_KOD\n")); 927 } 928 return; /* rate exceeded */ 929 } 930 if (hismode == MODE_CLIENT) { 931 fast_xmit(rbufp, MODE_SERVER, skeyid, 932 restrict_mask); 933 } else { 934 fast_xmit(rbufp, MODE_ACTIVE, skeyid, 935 restrict_mask); 936 } 937 return; /* rate exceeded */ 938 } 939 restrict_mask &= ~RES_KOD; 940 941 /* 942 * We have tossed out as many buggy packets as possible early in 943 * the game to reduce the exposure to a clogging attack. Now we 944 * have to burn some cycles to find the association and 945 * authenticate the packet if required. Note that we burn only 946 * digest cycles, again to reduce exposure. There may be no 947 * matching association and that's okay. 948 * 949 * More on the autokey mambo. Normally the local interface is 950 * found when the association was mobilized with respect to a 951 * designated remote address. We assume packets arriving from 952 * the remote address arrive via this interface and the local 953 * address used to construct the autokey is the unicast address 954 * of the interface. However, if the sender is a broadcaster, 955 * the interface broadcast address is used instead. 956 * Notwithstanding this technobabble, if the sender is a 957 * multicaster, the broadcast address is null, so we use the 958 * unicast address anyway. Don't ask. 959 */ 960 961 peer = findpeer(rbufp, hismode, &retcode); 962 dstadr_sin = &rbufp->dstadr->sin; 963 NTOHL_FP(&pkt->org, &p_org); 964 NTOHL_FP(&pkt->rec, &p_rec); 965 NTOHL_FP(&pkt->xmt, &p_xmt); 966 hm_str = modetoa(hismode); 967 am_str = amtoa(retcode); 968 969 /* 970 * Authentication is conditioned by three switches: 971 * 972 * NOPEER (RES_NOPEER) do not mobilize an association unless 973 * authenticated 974 * NOTRUST (RES_DONTTRUST) do not allow access unless 975 * authenticated (implies NOPEER) 976 * enable (sys_authenticate) master NOPEER switch, by default 977 * on 978 * 979 * The NOPEER and NOTRUST can be specified on a per-client basis 980 * using the restrict command. The enable switch if on implies 981 * NOPEER for all clients. There are four outcomes: 982 * 983 * NONE The packet has no MAC. 984 * OK the packet has a MAC and authentication succeeds 985 * ERROR the packet has a MAC and authentication fails 986 * CRYPTO crypto-NAK. The MAC has four octets only. 987 * 988 * Note: The AUTH(x, y) macro is used to filter outcomes. If x 989 * is zero, acceptable outcomes of y are NONE and OK. If x is 990 * one, the only acceptable outcome of y is OK. 991 */ 992 crypto_nak_test = valid_NAK(peer, rbufp, hismode); 993 994 /* 995 * Drop any invalid crypto-NAKs 996 */ 997 if (crypto_nak_test == INVALIDNAK) { 998 report_event(PEVNT_AUTH, peer, "Invalid_NAK"); 999 if (0 != peer) { 1000 peer->badNAK++; 1001 } 1002 msyslog(LOG_ERR, "Invalid-NAK error at %ld %s<-%s", 1003 current_time, stoa(dstadr_sin), stoa(&rbufp->recv_srcadr)); 1004 return; 1005 } 1006 1007 if (has_mac == 0) { 1008 restrict_mask &= ~RES_MSSNTP; 1009 is_authentic = AUTH_NONE; /* not required */ 1010 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x NOMAC\n", 1011 current_time, stoa(dstadr_sin), 1012 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 1013 authlen, 1014 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1015 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 1016 } else if (crypto_nak_test == VALIDNAK) { 1017 restrict_mask &= ~RES_MSSNTP; 1018 is_authentic = AUTH_CRYPTO; /* crypto-NAK */ 1019 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x CRYPTONAK\n", 1020 current_time, stoa(dstadr_sin), 1021 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 1022 skeyid, authlen + has_mac, is_authentic, 1023 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1024 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 1025 1026#ifdef HAVE_NTP_SIGND 1027 /* 1028 * If the signature is 20 bytes long, the last 16 of 1029 * which are zero, then this is a Microsoft client 1030 * wanting AD-style authentication of the server's 1031 * reply. 1032 * 1033 * This is described in Microsoft's WSPP docs, in MS-SNTP: 1034 * http://msdn.microsoft.com/en-us/library/cc212930.aspx 1035 */ 1036 } else if ( has_mac == MAX_MD5_LEN 1037 && (restrict_mask & RES_MSSNTP) 1038 && (retcode == AM_FXMIT || retcode == AM_NEWPASS) 1039 && (memcmp(zero_key, (char *)pkt + authlen + 4, 1040 MAX_MD5_LEN - 4) == 0)) { 1041 is_authentic = AUTH_NONE; 1042 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s len %d org %#010x.%08x xmt %#010x.%08x SIGND\n", 1043 current_time, stoa(dstadr_sin), 1044 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 1045 authlen, 1046 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1047 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 1048#endif /* HAVE_NTP_SIGND */ 1049 1050 } else { 1051 /* 1052 * has_mac is not 0 1053 * Not a VALID_NAK 1054 * Not an MS-SNTP SIGND packet 1055 * 1056 * So there is a MAC here. 1057 */ 1058 1059 restrict_mask &= ~RES_MSSNTP; 1060#ifdef AUTOKEY 1061 /* 1062 * For autokey modes, generate the session key 1063 * and install in the key cache. Use the socket 1064 * broadcast or unicast address as appropriate. 1065 */ 1066 if (crypto_flags && skeyid > NTP_MAXKEY) { 1067 1068 /* 1069 * More on the autokey dance (AKD). A cookie is 1070 * constructed from public and private values. 1071 * For broadcast packets, the cookie is public 1072 * (zero). For packets that match no 1073 * association, the cookie is hashed from the 1074 * addresses and private value. For server 1075 * packets, the cookie was previously obtained 1076 * from the server. For symmetric modes, the 1077 * cookie was previously constructed using an 1078 * agreement protocol; however, should PKI be 1079 * unavailable, we construct a fake agreement as 1080 * the EXOR of the peer and host cookies. 1081 * 1082 * hismode ephemeral persistent 1083 * ======================================= 1084 * active 0 cookie# 1085 * passive 0% cookie# 1086 * client sys cookie 0% 1087 * server 0% sys cookie 1088 * broadcast 0 0 1089 * 1090 * # if unsync, 0 1091 * % can't happen 1092 */ 1093 if (has_mac < (int)MAX_MD5_LEN) { 1094 DPRINTF(2, ("receive: drop: MD5 digest too short\n")); 1095 sys_badauth++; 1096 return; 1097 } 1098 if (hismode == MODE_BROADCAST) { 1099 1100 /* 1101 * For broadcaster, use the interface 1102 * broadcast address when available; 1103 * otherwise, use the unicast address 1104 * found when the association was 1105 * mobilized. However, if this is from 1106 * the wildcard interface, game over. 1107 */ 1108 if ( crypto_flags 1109 && rbufp->dstadr == 1110 ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) { 1111 DPRINTF(2, ("receive: drop: BCAST from wildcard\n")); 1112 sys_restricted++; 1113 return; /* no wildcard */ 1114 } 1115 pkeyid = 0; 1116 if (!SOCK_UNSPEC(&rbufp->dstadr->bcast)) 1117 dstadr_sin = 1118 &rbufp->dstadr->bcast; 1119 } else if (peer == NULL) { 1120 pkeyid = session_key( 1121 &rbufp->recv_srcadr, dstadr_sin, 0, 1122 sys_private, 0); 1123 } else { 1124 pkeyid = peer->pcookie; 1125 } 1126 1127 /* 1128 * The session key includes both the public 1129 * values and cookie. In case of an extension 1130 * field, the cookie used for authentication 1131 * purposes is zero. Note the hash is saved for 1132 * use later in the autokey mambo. 1133 */ 1134 if (authlen > (int)LEN_PKT_NOMAC && pkeyid != 0) { 1135 session_key(&rbufp->recv_srcadr, 1136 dstadr_sin, skeyid, 0, 2); 1137 tkeyid = session_key( 1138 &rbufp->recv_srcadr, dstadr_sin, 1139 skeyid, pkeyid, 0); 1140 } else { 1141 tkeyid = session_key( 1142 &rbufp->recv_srcadr, dstadr_sin, 1143 skeyid, pkeyid, 2); 1144 } 1145 1146 } 1147#endif /* AUTOKEY */ 1148 1149 /* 1150 * Compute the cryptosum. Note a clogging attack may 1151 * succeed in bloating the key cache. If an autokey, 1152 * purge it immediately, since we won't be needing it 1153 * again. If the packet is authentic, it can mobilize an 1154 * association. Note that there is no key zero. 1155 */ 1156 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen, 1157 has_mac)) 1158 is_authentic = AUTH_ERROR; 1159 else 1160 is_authentic = AUTH_OK; 1161#ifdef AUTOKEY 1162 if (crypto_flags && skeyid > NTP_MAXKEY) 1163 authtrust(skeyid, 0); 1164#endif /* AUTOKEY */ 1165 DPRINTF(1, ("receive: at %ld %s<-%s mode %d/%s:%s keyid %08x len %d auth %d org %#010x.%08x xmt %#010x.%08x MAC\n", 1166 current_time, stoa(dstadr_sin), 1167 stoa(&rbufp->recv_srcadr), hismode, hm_str, am_str, 1168 skeyid, authlen + has_mac, is_authentic, 1169 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 1170 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf))); 1171 } 1172 1173 1174 /* 1175 * Bug 3454: 1176 * 1177 * Now come at this from a different perspective: 1178 * - If we expect a MAC and it's not there, we drop it. 1179 * - If we expect one keyID and get another, we drop it. 1180 * - If we have a MAC ahd it hasn't been validated yet, try. 1181 * - if the provided MAC doesn't validate, we drop it. 1182 * 1183 * There might be more to this. 1184 */ 1185 if (0 != peer && 0 != peer->keyid) { 1186 /* Should we msyslog() any of these? */ 1187 1188 /* 1189 * This should catch: 1190 * - no keyID where one is expected, 1191 * - different keyID than what we expect. 1192 */ 1193 if (peer->keyid != skeyid) { 1194 DPRINTF(2, ("receive: drop: Wanted keyID %d, got %d from %s\n", 1195 peer->keyid, skeyid, 1196 stoa(&rbufp->recv_srcadr))); 1197 sys_restricted++; 1198 return; /* drop: access denied */ 1199 } 1200 1201 /* 1202 * if has_mac != 0 ... 1203 * - If it has not yet been validated, do so. 1204 * (under what circumstances might that happen?) 1205 * - if missing or bad MAC, log and drop. 1206 */ 1207 if (0 != has_mac) { 1208 if (is_authentic == AUTH_UNKNOWN) { 1209 /* How can this happen? */ 1210 DPRINTF(2, ("receive: 3454 check: AUTH_UNKNOWN from %s\n", 1211 stoa(&rbufp->recv_srcadr))); 1212 if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen, 1213 has_mac)) { 1214 /* MAC invalid or not found */ 1215 is_authentic = AUTH_ERROR; 1216 } else { 1217 is_authentic = AUTH_OK; 1218 } 1219 } 1220 if (is_authentic != AUTH_OK) { 1221 DPRINTF(2, ("receive: drop: missing or bad MAC from %s\n", 1222 stoa(&rbufp->recv_srcadr))); 1223 sys_restricted++; 1224 return; /* drop: access denied */ 1225 } 1226 } 1227 } 1228 /**/ 1229 1230 /* 1231 ** On-Wire Protocol Layer 1232 ** 1233 ** Verify protocol operations consistent with the on-wire protocol. 1234 ** The protocol discards bogus and duplicate packets as well as 1235 ** minimizes disruptions doe to protocol restarts and dropped 1236 ** packets. The operations are controlled by two timestamps: 1237 ** the transmit timestamp saved in the client state variables, 1238 ** and the origin timestamp in the server packet header. The 1239 ** comparison of these two timestamps is called the loopback test. 1240 ** The transmit timestamp functions as a nonce to verify that the 1241 ** response corresponds to the original request. The transmit 1242 ** timestamp also serves to discard replays of the most recent 1243 ** packet. Upon failure of either test, the packet is discarded 1244 ** with no further action. 1245 */ 1246 1247 /* 1248 * The association matching rules are implemented by a set of 1249 * routines and an association table. A packet matching an 1250 * association is processed by the peer process for that 1251 * association. If there are no errors, an ephemeral association 1252 * is mobilized: a broadcast packet mobilizes a broadcast client 1253 * aassociation; a manycast server packet mobilizes a manycast 1254 * client association; a symmetric active packet mobilizes a 1255 * symmetric passive association. 1256 */ 1257 DPRINTF(1, ("receive: MATCH_ASSOC dispatch: mode %d/%s:%s \n", 1258 hismode, hm_str, am_str)); 1259 switch (retcode) { 1260 1261 /* 1262 * This is a client mode packet not matching any association. If 1263 * an ordinary client, simply toss a server mode packet back 1264 * over the fence. If a manycast client, we have to work a 1265 * little harder. 1266 * 1267 * There are cases here where we do not call record_raw_stats(). 1268 */ 1269 case AM_FXMIT: 1270 1271 /* 1272 * If authentication OK, send a server reply; otherwise, 1273 * send a crypto-NAK. 1274 */ 1275 if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) { 1276 /* HMS: would be nice to log FAST_XMIT|BADAUTH|RESTRICTED */ 1277 record_raw_stats(&rbufp->recv_srcadr, 1278 &rbufp->dstadr->sin, 1279 &p_org, &p_rec, &p_xmt, &rbufp->recv_time, 1280 PKT_LEAP(pkt->li_vn_mode), 1281 PKT_VERSION(pkt->li_vn_mode), 1282 PKT_MODE(pkt->li_vn_mode), 1283 PKT_TO_STRATUM(pkt->stratum), 1284 pkt->ppoll, 1285 pkt->precision, 1286 FPTOD(NTOHS_FP(pkt->rootdelay)), 1287 FPTOD(NTOHS_FP(pkt->rootdisp)), 1288 pkt->refid, 1289 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten); 1290 1291 if (AUTH(restrict_mask & RES_DONTTRUST, 1292 is_authentic)) { 1293 /* Bug 3596: Do we want to fuzz the reftime? */ 1294 fast_xmit(rbufp, MODE_SERVER, skeyid, 1295 restrict_mask); 1296 } else if (is_authentic == AUTH_ERROR) { 1297 /* Bug 3596: Do we want to fuzz the reftime? */ 1298 fast_xmit(rbufp, MODE_SERVER, 0, 1299 restrict_mask); 1300 sys_badauth++; 1301 } else { 1302 DPRINTF(2, ("receive: AM_FXMIT drop: !mcast restricted\n")); 1303 sys_restricted++; 1304 } 1305 1306 return; /* hooray */ 1307 } 1308 1309 /* 1310 * This must be manycast. Do not respond if not 1311 * configured as a manycast server. 1312 */ 1313 if (!sys_manycastserver) { 1314 DPRINTF(2, ("receive: AM_FXMIT drop: Not manycastserver\n")); 1315 sys_restricted++; 1316 return; /* not enabled */ 1317 } 1318 1319#ifdef AUTOKEY 1320 /* 1321 * Do not respond if not the same group. 1322 */ 1323 if (group_test(groupname, NULL)) { 1324 DPRINTF(2, ("receive: AM_FXMIT drop: empty groupname\n")); 1325 sys_declined++; 1326 return; 1327 } 1328#endif /* AUTOKEY */ 1329 1330 /* 1331 * Do not respond if we are not synchronized or our 1332 * stratum is greater than the manycaster or the 1333 * manycaster has already synchronized to us. 1334 */ 1335 if ( sys_leap == LEAP_NOTINSYNC 1336 || sys_stratum >= hisstratum 1337 || (!sys_cohort && sys_stratum == hisstratum + 1) 1338 || rbufp->dstadr->addr_refid == pkt->refid) { 1339 DPRINTF(2, ("receive: AM_FXMIT drop: LEAP_NOTINSYNC || stratum || loop\n")); 1340 sys_declined++; 1341 return; /* no help */ 1342 } 1343 1344 /* 1345 * Respond only if authentication succeeds. Don't do a 1346 * crypto-NAK, as that would not be useful. 1347 */ 1348 if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) { 1349 record_raw_stats(&rbufp->recv_srcadr, 1350 &rbufp->dstadr->sin, 1351 &p_org, &p_rec, &p_xmt, &rbufp->recv_time, 1352 PKT_LEAP(pkt->li_vn_mode), 1353 PKT_VERSION(pkt->li_vn_mode), 1354 PKT_MODE(pkt->li_vn_mode), 1355 PKT_TO_STRATUM(pkt->stratum), 1356 pkt->ppoll, 1357 pkt->precision, 1358 FPTOD(NTOHS_FP(pkt->rootdelay)), 1359 FPTOD(NTOHS_FP(pkt->rootdisp)), 1360 pkt->refid, 1361 rbufp->recv_length - MIN_V4_PKT_LEN, (u_char *)&pkt->exten); 1362 1363 /* Bug 3596: Do we want to fuzz the reftime? */ 1364 fast_xmit(rbufp, MODE_SERVER, skeyid, 1365 restrict_mask); 1366 } 1367 return; /* hooray */ 1368 1369 /* 1370 * This is a server mode packet returned in response to a client 1371 * mode packet sent to a multicast group address (for 1372 * manycastclient) or to a unicast address (for pool). The 1373 * origin timestamp is a good nonce to reliably associate the 1374 * reply with what was sent. If there is no match, that's 1375 * curious and could be an intruder attempting to clog, so we 1376 * just ignore it. 1377 * 1378 * If the packet is authentic and the manycastclient or pool 1379 * association is found, we mobilize a client association and 1380 * copy pertinent variables from the manycastclient or pool 1381 * association to the new client association. If not, just 1382 * ignore the packet. 1383 * 1384 * There is an implosion hazard at the manycast client, since 1385 * the manycast servers send the server packet immediately. If 1386 * the guy is already here, don't fire up a duplicate. 1387 * 1388 * There are cases here where we do not call record_raw_stats(). 1389 */ 1390 case AM_MANYCAST: 1391 1392#ifdef AUTOKEY 1393 /* 1394 * Do not respond if not the same group. 1395 */ 1396 if (group_test(groupname, NULL)) { 1397 DPRINTF(2, ("receive: AM_MANYCAST drop: empty groupname\n")); 1398 sys_declined++; 1399 return; 1400 } 1401#endif /* AUTOKEY */ 1402 if ((peer2 = findmanycastpeer(rbufp)) == NULL) { 1403 DPRINTF(2, ("receive: AM_MANYCAST drop: No manycast peer\n")); 1404 sys_restricted++; 1405 return; /* not enabled */ 1406 } 1407 if (!AUTH( (!(peer2->cast_flags & MDF_POOL) 1408 && sys_authenticate) 1409 || (restrict_mask & (RES_NOPEER | 1410 RES_DONTTRUST)), is_authentic) 1411 /* MC: RES_NOEPEER? */ 1412 ) { 1413 DPRINTF(2, ("receive: AM_MANYCAST drop: bad auth || (NOPEER|DONTTRUST)\n")); 1414 sys_restricted++; 1415 return; /* access denied */ 1416 } 1417 1418 /* 1419 * Do not respond if unsynchronized or stratum is below 1420 * the floor or at or above the ceiling. 1421 */ 1422 if ( hisleap == LEAP_NOTINSYNC 1423 || hisstratum < sys_floor 1424 || hisstratum >= sys_ceiling) { 1425 DPRINTF(2, ("receive: AM_MANYCAST drop: unsync/stratum\n")); 1426 sys_declined++; 1427 return; /* no help */ 1428 } 1429 peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr, 1430 r4a.ippeerlimit, MODE_CLIENT, hisversion, 1431 peer2->minpoll, peer2->maxpoll, 1432 (FLAG_PREEMPT | (POOL_FLAG_PMASK & peer2->flags)), 1433 (MDF_UCAST | MDF_UCLNT), 0, skeyid, sys_ident); 1434 if (NULL == peer) { 1435 DPRINTF(2, ("receive: AM_MANYCAST drop: duplicate\n")); 1436 sys_declined++; 1437 return; /* ignore duplicate */ 1438 } 1439 1440 /* 1441 * After each ephemeral pool association is spun, 1442 * accelerate the next poll for the pool solicitor so 1443 * the pool will fill promptly. 1444 */ 1445 if (peer2->cast_flags & MDF_POOL) 1446 peer2->nextdate = current_time + 1; 1447 1448 /* 1449 * Further processing of the solicitation response would 1450 * simply detect its origin timestamp as bogus for the 1451 * brand-new association (it matches the prototype 1452 * association) and tinker with peer->nextdate delaying 1453 * first sync. 1454 */ 1455 return; /* solicitation response handled */ 1456 1457 /* 1458 * This is the first packet received from a broadcast server. If 1459 * the packet is authentic and we are enabled as broadcast 1460 * client, mobilize a broadcast client association. We don't 1461 * kiss any frogs here. 1462 * 1463 * There are cases here where we do not call record_raw_stats(). 1464 */ 1465 case AM_NEWBCL: 1466 1467#ifdef AUTOKEY 1468 /* 1469 * Do not respond if not the same group. 1470 */ 1471 if (group_test(groupname, sys_ident)) { 1472 DPRINTF(2, ("receive: AM_NEWBCL drop: groupname mismatch\n")); 1473 sys_declined++; 1474 return; 1475 } 1476#endif /* AUTOKEY */ 1477 if (sys_bclient == 0) { 1478 DPRINTF(2, ("receive: AM_NEWBCL drop: not a bclient\n")); 1479 sys_restricted++; 1480 return; /* not enabled */ 1481 } 1482 if (!AUTH(sys_authenticate | (restrict_mask & 1483 (RES_NOPEER | RES_DONTTRUST)), is_authentic) 1484 /* NEWBCL: RES_NOEPEER? */ 1485 ) { 1486 DPRINTF(2, ("receive: AM_NEWBCL drop: AUTH failed\n")); 1487 sys_restricted++; 1488 return; /* access denied */ 1489 } 1490 1491 /* 1492 * Do not respond if unsynchronized or stratum is below 1493 * the floor or at or above the ceiling. 1494 */ 1495 if ( hisleap == LEAP_NOTINSYNC 1496 || hisstratum < sys_floor 1497 || hisstratum >= sys_ceiling) { 1498 DPRINTF(2, ("receive: AM_NEWBCL drop: Unsync or bad stratum\n")); 1499 sys_declined++; 1500 return; /* no help */ 1501 } 1502 1503#ifdef AUTOKEY 1504 /* 1505 * Do not respond if Autokey and the opcode is not a 1506 * CRYPTO_ASSOC response with association ID. 1507 */ 1508 if ( crypto_flags && skeyid > NTP_MAXKEY 1509 && (opcode & 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) { 1510 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not CRYPTO_ASSOC\n")); 1511 sys_declined++; 1512 return; /* protocol error */ 1513 } 1514#endif /* AUTOKEY */ 1515 1516 /* 1517 * Broadcasts received via a multicast address may 1518 * arrive after a unicast volley has begun 1519 * with the same remote address. newpeer() will not 1520 * find duplicate associations on other local endpoints 1521 * if a non-NULL endpoint is supplied. multicastclient 1522 * ephemeral associations are unique across all local 1523 * endpoints. 1524 */ 1525 if (!(INT_MCASTOPEN & rbufp->dstadr->flags)) 1526 match_ep = rbufp->dstadr; 1527 else 1528 match_ep = NULL; 1529 1530 /* 1531 * Determine whether to execute the initial volley. 1532 */ 1533 if (sys_bdelay > 0.0) { 1534#ifdef AUTOKEY 1535 /* 1536 * If a two-way exchange is not possible, 1537 * neither is Autokey. 1538 */ 1539 if (crypto_flags && skeyid > NTP_MAXKEY) { 1540 sys_restricted++; 1541 DPRINTF(2, ("receive: AM_NEWBCL drop: Autokey but not 2-way\n")); 1542 return; /* no autokey */ 1543 } 1544#endif /* AUTOKEY */ 1545 1546 /* 1547 * Do not execute the volley. Start out in 1548 * broadcast client mode. 1549 */ 1550 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep, 1551 r4a.ippeerlimit, MODE_BCLIENT, hisversion, 1552 pkt->ppoll, pkt->ppoll, 1553 FLAG_PREEMPT, MDF_BCLNT, 0, skeyid, sys_ident); 1554 if (NULL == peer) { 1555 DPRINTF(2, ("receive: AM_NEWBCL drop: duplicate\n")); 1556 sys_restricted++; 1557 return; /* ignore duplicate */ 1558 1559 } else { 1560 peer->delay = sys_bdelay; 1561 peer->bxmt = p_xmt; 1562 } 1563 break; 1564 } 1565 1566 /* 1567 * Execute the initial volley in order to calibrate the 1568 * propagation delay and run the Autokey protocol. 1569 * 1570 * Note that the minpoll is taken from the broadcast 1571 * packet, normally 6 (64 s) and that the poll interval 1572 * is fixed at this value. 1573 */ 1574 peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep, 1575 r4a.ippeerlimit, MODE_CLIENT, hisversion, 1576 pkt->ppoll, pkt->ppoll, 1577 FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT, 1578 0, skeyid, sys_ident); 1579 if (NULL == peer) { 1580 DPRINTF(2, ("receive: AM_NEWBCL drop: empty newpeer() failed\n")); 1581 sys_restricted++; 1582 return; /* ignore duplicate */ 1583 } 1584 peer->bxmt = p_xmt; 1585#ifdef AUTOKEY 1586 if (skeyid > NTP_MAXKEY) 1587 crypto_recv(peer, rbufp); 1588#endif /* AUTOKEY */ 1589 1590 return; /* hooray */ 1591 1592 /* 1593 * This is the first packet received from a potential ephemeral 1594 * symmetric active peer. First, deal with broken Windows clients. 1595 * Then, if NOEPEER is enabled, drop it. If the packet meets our 1596 * authenticty requirements and is the first he sent, mobilize 1597 * a passive association. 1598 * Otherwise, kiss the frog. 1599 * 1600 * There are cases here where we do not call record_raw_stats(). 1601 */ 1602 case AM_NEWPASS: 1603 1604 DEBUG_REQUIRE(MODE_ACTIVE == hismode); 1605 1606#ifdef AUTOKEY 1607 /* 1608 * Do not respond if not the same group. 1609 */ 1610 if (group_test(groupname, sys_ident)) { 1611 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n")); 1612 sys_declined++; 1613 return; 1614 } 1615#endif /* AUTOKEY */ 1616 if (!AUTH(sys_authenticate | (restrict_mask & 1617 (RES_NOPEER | RES_DONTTRUST)), is_authentic) 1618 ) { 1619 /* 1620 * If authenticated but cannot mobilize an 1621 * association, send a symmetric passive 1622 * response without mobilizing an association. 1623 * This is for drat broken Windows clients. See 1624 * Microsoft KB 875424 for preferred workaround. 1625 */ 1626 if (AUTH(restrict_mask & RES_DONTTRUST, 1627 is_authentic)) { 1628 fast_xmit(rbufp, MODE_PASSIVE, skeyid, 1629 restrict_mask); 1630 return; /* hooray */ 1631 } 1632 /* HMS: Why is this next set of lines a feature? */ 1633 if (is_authentic == AUTH_ERROR) { 1634 fast_xmit(rbufp, MODE_PASSIVE, 0, 1635 restrict_mask); 1636 sys_restricted++; 1637 return; 1638 } 1639 1640 if (restrict_mask & RES_NOEPEER) { 1641 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n")); 1642 sys_declined++; 1643 return; 1644 } 1645 1646 /* [Bug 2941] 1647 * If we got here, the packet isn't part of an 1648 * existing association, either isn't correctly 1649 * authenticated or it is but we are refusing 1650 * ephemeral peer requests, and it didn't meet 1651 * either of the previous two special cases so we 1652 * should just drop it on the floor. For example, 1653 * crypto-NAKs (is_authentic == AUTH_CRYPTO) 1654 * will make it this far. This is just 1655 * debug-printed and not logged to avoid log 1656 * flooding. 1657 */ 1658 DPRINTF(2, ("receive: at %ld refusing to mobilize passive association" 1659 " with unknown peer %s mode %d/%s:%s keyid %08x len %d auth %d\n", 1660 current_time, stoa(&rbufp->recv_srcadr), 1661 hismode, hm_str, am_str, skeyid, 1662 (authlen + has_mac), is_authentic)); 1663 sys_declined++; 1664 return; 1665 } 1666 1667 if (restrict_mask & RES_NOEPEER) { 1668 DPRINTF(2, ("receive: AM_NEWPASS drop: NOEPEER\n")); 1669 sys_declined++; 1670 return; 1671 } 1672 1673 /* 1674 * Do not respond if synchronized and if stratum is 1675 * below the floor or at or above the ceiling. Note, 1676 * this allows an unsynchronized peer to synchronize to 1677 * us. It would be very strange if he did and then was 1678 * nipped, but that could only happen if we were 1679 * operating at the top end of the range. It also means 1680 * we will spin an ephemeral association in response to 1681 * MODE_ACTIVE KoDs, which will time out eventually. 1682 */ 1683 if ( hisleap != LEAP_NOTINSYNC 1684 && (hisstratum < sys_floor || hisstratum >= sys_ceiling)) { 1685 DPRINTF(2, ("receive: AM_NEWPASS drop: Autokey group mismatch\n")); 1686 sys_declined++; 1687 return; /* no help */ 1688 } 1689 1690 /* 1691 * The message is correctly authenticated and allowed. 1692 * Mobilize a symmetric passive association, if we won't 1693 * exceed the ippeerlimit. 1694 */ 1695 if ((peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr, 1696 r4a.ippeerlimit, MODE_PASSIVE, hisversion, 1697 pkt->ppoll, NTP_MAXDPOLL, 0, MDF_UCAST, 0, 1698 skeyid, sys_ident)) == NULL) { 1699 DPRINTF(2, ("receive: AM_NEWPASS drop: newpeer() failed\n")); 1700 sys_declined++; 1701 return; /* ignore duplicate */ 1702 } 1703 break; 1704 1705 1706 /* 1707 * Process regular packet. Nothing special. 1708 * 1709 * There are cases here where we do not call record_raw_stats(). 1710 */ 1711 case AM_PROCPKT: 1712 1713#ifdef AUTOKEY 1714 /* 1715 * Do not respond if not the same group. 1716 */ 1717 if (group_test(groupname, peer->ident)) { 1718 DPRINTF(2, ("receive: AM_PROCPKT drop: Autokey group mismatch\n")); 1719 sys_declined++; 1720 return; 1721 } 1722#endif /* AUTOKEY */ 1723 1724 if (MODE_BROADCAST == hismode) { 1725 int bail = 0; 1726 l_fp tdiff; 1727 u_long deadband; 1728 1729 DPRINTF(2, ("receive: PROCPKT/BROADCAST: prev pkt %ld seconds ago, ppoll: %d, %d secs\n", 1730 (current_time - peer->timelastrec), 1731 peer->ppoll, (1 << peer->ppoll) 1732 )); 1733 /* Things we can check: 1734 * 1735 * Did the poll interval change? 1736 * Is the poll interval in the packet in-range? 1737 * Did this packet arrive too soon? 1738 * Is the timestamp in this packet monotonic 1739 * with respect to the previous packet? 1740 */ 1741 1742 /* This is noteworthy, not error-worthy */ 1743 if (pkt->ppoll != peer->ppoll) { 1744 msyslog(LOG_INFO, "receive: broadcast poll from %s changed from %u to %u", 1745 stoa(&rbufp->recv_srcadr), 1746 peer->ppoll, pkt->ppoll); 1747 } 1748 1749 /* This is error-worthy */ 1750 if ( pkt->ppoll < peer->minpoll 1751 || pkt->ppoll > peer->maxpoll) { 1752 msyslog(LOG_INFO, "receive: broadcast poll of %u from %s is out-of-range (%d to %d)!", 1753 pkt->ppoll, stoa(&rbufp->recv_srcadr), 1754 peer->minpoll, peer->maxpoll); 1755 ++bail; 1756 } 1757 1758 /* too early? worth an error, too! 1759 * 1760 * [Bug 3113] Ensure that at least one poll 1761 * interval has elapsed since the last **clean** 1762 * packet was received. We limit the check to 1763 * **clean** packets to prevent replayed packets 1764 * and incorrectly authenticated packets, which 1765 * we'll discard, from being used to create a 1766 * denial of service condition. 1767 */ 1768 deadband = (1u << pkt->ppoll); 1769 if (FLAG_BC_VOL & peer->flags) 1770 deadband -= 3; /* allow greater fuzz after volley */ 1771 if ((current_time - peer->timereceived) < deadband) { 1772 msyslog(LOG_INFO, "receive: broadcast packet from %s arrived after %lu, not %lu seconds!", 1773 stoa(&rbufp->recv_srcadr), 1774 (current_time - peer->timereceived), 1775 deadband); 1776 ++bail; 1777 } 1778 1779 /* Alert if time from the server is non-monotonic. 1780 * 1781 * [Bug 3114] is about Broadcast mode replay DoS. 1782 * 1783 * Broadcast mode *assumes* a trusted network. 1784 * Even so, it's nice to be robust in the face 1785 * of attacks. 1786 * 1787 * If we get an authenticated broadcast packet 1788 * with an "earlier" timestamp, it means one of 1789 * two things: 1790 * 1791 * - the broadcast server had a backward step. 1792 * 1793 * - somebody is trying a replay attack. 1794 * 1795 * deadband: By default, we assume the broadcast 1796 * network is trustable, so we take our accepted 1797 * broadcast packets as we receive them. But 1798 * some folks might want to take additional poll 1799 * delays before believing a backward step. 1800 */ 1801 if (sys_bcpollbstep) { 1802 /* pkt->ppoll or peer->ppoll ? */ 1803 deadband = (1u << pkt->ppoll) 1804 * sys_bcpollbstep + 2; 1805 } else { 1806 deadband = 0; 1807 } 1808 1809 if (L_ISZERO(&peer->bxmt)) { 1810 tdiff.l_ui = tdiff.l_uf = 0; 1811 } else { 1812 tdiff = p_xmt; 1813 L_SUB(&tdiff, &peer->bxmt); 1814 } 1815 if ( tdiff.l_i < 0 1816 && (current_time - peer->timereceived) < deadband) 1817 { 1818 msyslog(LOG_INFO, "receive: broadcast packet from %s contains non-monotonic timestamp: %#010x.%08x -> %#010x.%08x", 1819 stoa(&rbufp->recv_srcadr), 1820 peer->bxmt.l_ui, peer->bxmt.l_uf, 1821 p_xmt.l_ui, p_xmt.l_uf 1822 ); 1823 ++bail; 1824 } 1825 1826 if (bail) { 1827 DPRINTF(2, ("receive: AM_PROCPKT drop: bail\n")); 1828 peer->timelastrec = current_time; 1829 sys_declined++; 1830 return; 1831 } 1832 } 1833 1834 break; 1835 1836 /* 1837 * A passive packet matches a passive association. This is 1838 * usually the result of reconfiguring a client on the fly. As 1839 * this association might be legitimate and this packet an 1840 * attempt to deny service, just ignore it. 1841 */ 1842 case AM_ERR: 1843 DPRINTF(2, ("receive: AM_ERR drop.\n")); 1844 sys_declined++; 1845 return; 1846 1847 /* 1848 * For everything else there is the bit bucket. 1849 */ 1850 default: 1851 DPRINTF(2, ("receive: default drop.\n")); 1852 sys_declined++; 1853 return; 1854 } 1855 1856#ifdef AUTOKEY 1857 /* 1858 * If the association is configured for Autokey, the packet must 1859 * have a public key ID; if not, the packet must have a 1860 * symmetric key ID. 1861 */ 1862 if ( is_authentic != AUTH_CRYPTO 1863 && ( ((peer->flags & FLAG_SKEY) && skeyid <= NTP_MAXKEY) 1864 || (!(peer->flags & FLAG_SKEY) && skeyid > NTP_MAXKEY))) { 1865 DPRINTF(2, ("receive: drop: Autokey but wrong/bad auth\n")); 1866 sys_badauth++; 1867 return; 1868 } 1869#endif /* AUTOKEY */ 1870 1871 peer->received++; 1872 peer->flash &= ~PKT_TEST_MASK; 1873 if (peer->flags & FLAG_XBOGUS) { 1874 peer->flags &= ~FLAG_XBOGUS; 1875 peer->flash |= TEST3; 1876 } 1877 1878 /* 1879 * Next comes a rigorous schedule of timestamp checking. If the 1880 * transmit timestamp is zero, the server has not initialized in 1881 * interleaved modes or is horribly broken. 1882 * 1883 * A KoD packet we pay attention to cannot have a 0 transmit 1884 * timestamp. 1885 */ 1886 1887 kissCode = kiss_code_check(hisleap, hisstratum, hismode, pkt->refid); 1888 1889 if (L_ISZERO(&p_xmt)) { 1890 peer->flash |= TEST3; /* unsynch */ 1891 if (kissCode != NOKISS) { /* KoD packet */ 1892 peer->bogusorg++; /* for TEST2 or TEST3 */ 1893 msyslog(LOG_INFO, 1894 "receive: Unexpected zero transmit timestamp in KoD from %s", 1895 ntoa(&peer->srcadr)); 1896 return; 1897 } 1898 1899 /* 1900 * If the transmit timestamp duplicates our previous one, the 1901 * packet is a replay. This prevents the bad guys from replaying 1902 * the most recent packet, authenticated or not. 1903 */ 1904 } else if ( ((FLAG_LOOPNONCE & peer->flags) && L_ISEQU(&peer->nonce, &p_xmt)) 1905 || (!(FLAG_LOOPNONCE & peer->flags) && L_ISEQU(&peer->xmt, &p_xmt)) 1906 ) { 1907 DPRINTF(2, ("receive: drop: Duplicate xmit\n")); 1908 peer->flash |= TEST1; /* duplicate */ 1909 peer->oldpkt++; 1910 return; 1911 1912 /* 1913 * If this is a broadcast mode packet, make sure hisstratum 1914 * is appropriate. Don't do anything else here - we wait to 1915 * see if this is an interleave broadcast packet until after 1916 * we've validated the MAC that SHOULD be provided. 1917 * 1918 * hisstratum cannot be 0 - see assertion above. 1919 * If hisstratum is 15, then we'll advertise as UNSPEC but 1920 * at least we'll be able to sync with the broadcast server. 1921 */ 1922 } else if (hismode == MODE_BROADCAST) { 1923 /* 0 is unexpected too, and impossible */ 1924 if (STRATUM_UNSPEC <= hisstratum) { 1925 /* Is this a ++sys_declined or ??? */ 1926 msyslog(LOG_INFO, 1927 "receive: Unexpected stratum (%d) in broadcast from %s", 1928 hisstratum, ntoa(&peer->srcadr)); 1929 return; 1930 } 1931 1932 /* 1933 * Basic KoD validation checking: 1934 * 1935 * KoD packets are a mixed-blessing. Forged KoD packets 1936 * are DoS attacks. There are rare situations where we might 1937 * get a valid KoD response, though. Since KoD packets are 1938 * a special case that complicate the checks we do next, we 1939 * handle the basic KoD checks here. 1940 * 1941 * Note that we expect the incoming KoD packet to have its 1942 * (nonzero) org, rec, and xmt timestamps set to the xmt timestamp 1943 * that we have previously sent out. Watch interleave mode. 1944 */ 1945 } else if (kissCode != NOKISS) { 1946 DEBUG_INSIST(!L_ISZERO(&p_xmt)); 1947 if ( L_ISZERO(&p_org) /* We checked p_xmt above */ 1948 || L_ISZERO(&p_rec)) { 1949 peer->bogusorg++; 1950 msyslog(LOG_INFO, 1951 "receive: KoD packet from %s has a zero org or rec timestamp. Ignoring.", 1952 ntoa(&peer->srcadr)); 1953 return; 1954 } 1955 1956 if ( !L_ISEQU(&p_xmt, &p_org) 1957 || !L_ISEQU(&p_xmt, &p_rec)) { 1958 peer->bogusorg++; 1959 msyslog(LOG_INFO, 1960 "receive: KoD packet from %s has inconsistent xmt/org/rec timestamps. Ignoring.", 1961 ntoa(&peer->srcadr)); 1962 return; 1963 } 1964 1965 /* Be conservative */ 1966 if (peer->flip == 0 && !L_ISEQU(&p_org, &peer->aorg)) { 1967 peer->bogusorg++; 1968 msyslog(LOG_INFO, 1969 "receive: flip 0 KoD origin timestamp %#010x.%08x from %s does not match %#010x.%08x - ignoring.", 1970 p_org.l_ui, p_org.l_uf, 1971 ntoa(&peer->srcadr), 1972 peer->aorg.l_ui, peer->aorg.l_uf); 1973 return; 1974 } else if (peer->flip == 1 && !L_ISEQU(&p_org, &peer->borg)) { 1975 peer->bogusorg++; 1976 msyslog(LOG_INFO, 1977 "receive: flip 1 KoD origin timestamp %#010x.%08x from %s does not match interleave %#010x.%08x - ignoring.", 1978 p_org.l_ui, p_org.l_uf, 1979 ntoa(&peer->srcadr), 1980 peer->borg.l_ui, peer->borg.l_uf); 1981 return; 1982 } 1983 1984 /* 1985 * Basic mode checks: 1986 * 1987 * If there is no origin timestamp, it's either an initial packet 1988 * or we've already received a response to our query. Of course, 1989 * should 'aorg' be all-zero because this really was the original 1990 * transmit timestamp, we'll ignore this reply. There is a window 1991 * of one nanosecond once every 136 years' time where this is 1992 * possible. We currently ignore this situation, as a completely 1993 * zero timestamp is (quietly?) disallowed. 1994 * 1995 * Otherwise, check for bogus packet in basic mode. 1996 * If it is bogus, switch to interleaved mode and resynchronize, 1997 * but only after confirming the packet is not bogus in 1998 * symmetric interleaved mode. 1999 * 2000 * This could also mean somebody is forging packets claiming to 2001 * be from us, attempting to cause our server to KoD us. 2002 * 2003 * We have earlier asserted that hisstratum cannot be 0. 2004 * If hisstratum is STRATUM_UNSPEC, it means he's not sync'd. 2005 */ 2006 2007 /* XXX: FLAG_LOOPNONCE */ 2008 DEBUG_INSIST(0 == (FLAG_LOOPNONCE & peer->flags)); 2009 2010 } else if (peer->flip == 0) { 2011 if (0) { 2012 } else if (L_ISZERO(&p_org)) { 2013 const char *action; 2014 2015#ifdef BUG3361 2016 msyslog(LOG_INFO, 2017 "receive: BUG 3361: Clearing peer->aorg "); 2018 L_CLR(&peer->aorg); 2019 /* Clear peer->nonce, too? */ 2020#endif 2021 /**/ 2022 switch (hismode) { 2023 /* We allow 0org for: */ 2024 case UCHAR_MAX: 2025 action = "Allow"; 2026 break; 2027 /* We disallow 0org for: */ 2028 case MODE_UNSPEC: 2029 case MODE_ACTIVE: 2030 case MODE_PASSIVE: 2031 case MODE_CLIENT: 2032 case MODE_SERVER: 2033 case MODE_BROADCAST: 2034 action = "Drop"; 2035 peer->bogusorg++; 2036 peer->flash |= TEST2; /* bogus */ 2037 break; 2038 default: 2039 action = ""; /* for cranky compilers / MSVC */ 2040 INSIST(!"receive(): impossible hismode"); 2041 break; 2042 } 2043 /**/ 2044 msyslog(LOG_INFO, 2045 "receive: %s 0 origin timestamp from %s@%s xmt %#010x.%08x", 2046 action, hm_str, ntoa(&peer->srcadr), 2047 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)); 2048 } else if (!L_ISEQU(&p_org, &peer->aorg)) { 2049 /* are there cases here where we should bail? */ 2050 /* Should we set TEST2 if we decide to try xleave? */ 2051 peer->bogusorg++; 2052 peer->flash |= TEST2; /* bogus */ 2053 msyslog(LOG_INFO, 2054 "receive: Unexpected origin timestamp %#010x.%08x does not match aorg %#010x.%08x from %s@%s xmt %#010x.%08x", 2055 ntohl(pkt->org.l_ui), ntohl(pkt->org.l_uf), 2056 peer->aorg.l_ui, peer->aorg.l_uf, 2057 hm_str, ntoa(&peer->srcadr), 2058 ntohl(pkt->xmt.l_ui), ntohl(pkt->xmt.l_uf)); 2059 if ( !L_ISZERO(&peer->dst) 2060 && L_ISEQU(&p_org, &peer->dst)) { 2061 /* Might be the start of an interleave */ 2062 if (dynamic_interleave) { 2063 peer->flip = 1; 2064 report_event(PEVNT_XLEAVE, peer, NULL); 2065 } else { 2066 msyslog(LOG_INFO, 2067 "receive: Dynamic interleave from %s@%s denied", 2068 hm_str, ntoa(&peer->srcadr)); 2069 } 2070 } 2071 } else { 2072 L_CLR(&peer->aorg); 2073 /* XXX: FLAG_LOOPNONCE */ 2074 } 2075 2076 /* 2077 * Check for valid nonzero timestamp fields. 2078 */ 2079 } else if ( L_ISZERO(&p_org) 2080 || L_ISZERO(&p_rec) 2081 || L_ISZERO(&peer->dst)) { 2082 peer->flash |= TEST3; /* unsynch */ 2083 2084 /* 2085 * Check for bogus packet in interleaved symmetric mode. This 2086 * can happen if a packet is lost, duplicated or crossed. If 2087 * found, flip and resynchronize. 2088 */ 2089 } else if ( !L_ISZERO(&peer->dst) 2090 && !L_ISEQU(&p_org, &peer->dst)) { 2091 DPRINTF(2, ("receive: drop: Bogus packet in interleaved symmetric mode\n")); 2092 peer->bogusorg++; 2093 peer->flags |= FLAG_XBOGUS; 2094 peer->flash |= TEST2; /* bogus */ 2095#ifdef BUG3453 2096 return; /* Bogus packet, we are done */ 2097#endif 2098 } 2099 2100 /**/ 2101 2102 /* 2103 * If this is a crypto_NAK, the server cannot authenticate a 2104 * client packet. The server might have just changed keys. Clear 2105 * the association and restart the protocol. 2106 */ 2107 if (crypto_nak_test == VALIDNAK) { 2108 report_event(PEVNT_AUTH, peer, "crypto_NAK"); 2109 peer->flash |= TEST5; /* bad auth */ 2110 peer->badauth++; 2111 if (peer->flags & FLAG_PREEMPT) { 2112 if (unpeer_crypto_nak_early) { 2113 unpeer(peer); 2114 } 2115 DPRINTF(2, ("receive: drop: PREEMPT crypto_NAK\n")); 2116 return; 2117 } 2118#ifdef AUTOKEY 2119 if (peer->crypto) { 2120 peer_clear(peer, "AUTH"); 2121 } 2122#endif /* AUTOKEY */ 2123 DPRINTF(2, ("receive: drop: crypto_NAK\n")); 2124 return; 2125 2126 /* 2127 * If the digest fails or it's missing for authenticated 2128 * associations, the client cannot authenticate a server 2129 * reply to a client packet previously sent. The loopback check 2130 * is designed to avoid a bait-and-switch attack, which was 2131 * possible in past versions. If symmetric modes, return a 2132 * crypto-NAK. The peer should restart the protocol. 2133 */ 2134 } else if (!AUTH(peer->keyid || has_mac || 2135 (restrict_mask & RES_DONTTRUST), is_authentic)) { 2136 2137 if (peer->flash & PKT_TEST_MASK) { 2138 msyslog(LOG_INFO, 2139 "receive: Bad auth in packet with bad timestamps from %s denied - spoof?", 2140 ntoa(&peer->srcadr)); 2141 return; 2142 } 2143 2144 report_event(PEVNT_AUTH, peer, "digest"); 2145 peer->flash |= TEST5; /* bad auth */ 2146 peer->badauth++; 2147 if ( has_mac 2148 && ( hismode == MODE_ACTIVE 2149 || hismode == MODE_PASSIVE)) 2150 fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask); 2151 if (peer->flags & FLAG_PREEMPT) { 2152 if (unpeer_digest_early) { 2153 unpeer(peer); 2154 } 2155 } 2156#ifdef AUTOKEY 2157 else if (peer_clear_digest_early && peer->crypto) { 2158 peer_clear(peer, "AUTH"); 2159 } 2160#endif /* AUTOKEY */ 2161 DPRINTF(2, ("receive: drop: Bad or missing AUTH\n")); 2162 return; 2163 } 2164 2165 /* 2166 * For broadcast packets: 2167 * 2168 * HMS: This next line never made much sense to me, even 2169 * when it was up higher: 2170 * If an initial volley, bail out now and let the 2171 * client do its stuff. 2172 * 2173 * If the packet has not failed authentication, then 2174 * - if the origin timestamp is nonzero this is an 2175 * interleaved broadcast, so restart the protocol. 2176 * - else, this is not an interleaved broadcast packet. 2177 */ 2178 if (hismode == MODE_BROADCAST) { 2179 if ( is_authentic == AUTH_OK 2180 || is_authentic == AUTH_NONE) { 2181 if (!L_ISZERO(&p_org)) { 2182 if (!(peer->flags & FLAG_XB)) { 2183 msyslog(LOG_INFO, 2184 "receive: Broadcast server at %s is in interleave mode", 2185 ntoa(&peer->srcadr)); 2186 peer->flags |= FLAG_XB; 2187 peer->aorg = p_xmt; 2188 peer->borg = rbufp->recv_time; 2189 report_event(PEVNT_XLEAVE, peer, NULL); 2190 return; 2191 } 2192 } else if (peer->flags & FLAG_XB) { 2193 msyslog(LOG_INFO, 2194 "receive: Broadcast server at %s is no longer in interleave mode", 2195 ntoa(&peer->srcadr)); 2196 peer->flags &= ~FLAG_XB; 2197 } 2198 } else { 2199 msyslog(LOG_INFO, 2200 "receive: Bad broadcast auth (%d) from %s", 2201 is_authentic, ntoa(&peer->srcadr)); 2202 } 2203 2204 /* 2205 * Now that we know the packet is correctly authenticated, 2206 * update peer->bxmt. 2207 */ 2208 peer->bxmt = p_xmt; 2209 } 2210 2211 2212 /* 2213 ** Update the state variables. 2214 */ 2215 if (peer->flip == 0) { 2216 if (hismode != MODE_BROADCAST) 2217 peer->rec = p_xmt; 2218 peer->dst = rbufp->recv_time; 2219 } 2220 peer->xmt = p_xmt; 2221 2222 /* 2223 * Set the peer ppoll to the maximum of the packet ppoll and the 2224 * peer minpoll. If a kiss-o'-death, set the peer minpoll to 2225 * this maximum and advance the headway to give the sender some 2226 * headroom. Very intricate. 2227 */ 2228 2229 /* 2230 * Check for any kiss codes. Note this is only used when a server 2231 * responds to a packet request. 2232 */ 2233 2234 /* 2235 * Check to see if this is a RATE Kiss Code 2236 * Currently this kiss code will accept whatever poll 2237 * rate that the server sends 2238 */ 2239 peer->ppoll = max(peer->minpoll, pkt->ppoll); 2240 if (kissCode == RATEKISS) { 2241 peer->selbroken++; /* Increment the KoD count */ 2242 report_event(PEVNT_RATE, peer, NULL); 2243 if (pkt->ppoll > peer->minpoll) 2244 peer->minpoll = peer->ppoll; 2245 peer->burst = peer->retry = 0; 2246 peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll); 2247 poll_update(peer, pkt->ppoll, 0); 2248 return; /* kiss-o'-death */ 2249 } 2250 if (kissCode != NOKISS) { 2251 peer->selbroken++; /* Increment the KoD count */ 2252 return; /* Drop any other kiss code packets */ 2253 } 2254 2255 2256 /* 2257 * XXX 2258 */ 2259 2260 2261 /* 2262 * If: 2263 * - this is a *cast (uni-, broad-, or m-) server packet 2264 * - and it's symmetric-key authenticated 2265 * then see if the sender's IP is trusted for this keyid. 2266 * If it is, great - nothing special to do here. 2267 * Otherwise, we should report and bail. 2268 * 2269 * Autokey-authenticated packets are accepted. 2270 */ 2271 2272 switch (hismode) { 2273 case MODE_SERVER: /* server mode */ 2274 case MODE_BROADCAST: /* broadcast mode */ 2275 case MODE_ACTIVE: /* symmetric active mode */ 2276 case MODE_PASSIVE: /* symmetric passive mode */ 2277 if ( is_authentic == AUTH_OK 2278 && skeyid 2279 && skeyid <= NTP_MAXKEY 2280 && !authistrustedip(skeyid, &peer->srcadr)) { 2281 report_event(PEVNT_AUTH, peer, "authIP"); 2282 peer->badauth++; 2283 return; 2284 } 2285 break; 2286 2287 case MODE_CLIENT: /* client mode */ 2288#if 0 /* At this point, MODE_CONTROL is overloaded by MODE_BCLIENT */ 2289 case MODE_CONTROL: /* control mode */ 2290#endif 2291 case MODE_PRIVATE: /* private mode */ 2292 case MODE_BCLIENT: /* broadcast client mode */ 2293 break; 2294 2295 case MODE_UNSPEC: /* unspecified (old version) */ 2296 default: 2297 msyslog(LOG_INFO, 2298 "receive: Unexpected mode (%d) in packet from %s", 2299 hismode, ntoa(&peer->srcadr)); 2300 break; 2301 } 2302 2303 2304 /* 2305 * That was hard and I am sweaty, but the packet is squeaky 2306 * clean. Get on with real work. 2307 */ 2308 peer->timereceived = current_time; 2309 peer->timelastrec = current_time; 2310 if (is_authentic == AUTH_OK) 2311 peer->flags |= FLAG_AUTHENTIC; 2312 else 2313 peer->flags &= ~FLAG_AUTHENTIC; 2314 2315#ifdef AUTOKEY 2316 /* 2317 * More autokey dance. The rules of the cha-cha are as follows: 2318 * 2319 * 1. If there is no key or the key is not auto, do nothing. 2320 * 2321 * 2. If this packet is in response to the one just previously 2322 * sent or from a broadcast server, do the extension fields. 2323 * Otherwise, assume bogosity and bail out. 2324 * 2325 * 3. If an extension field contains a verified signature, it is 2326 * self-authenticated and we sit the dance. 2327 * 2328 * 4. If this is a server reply, check only to see that the 2329 * transmitted key ID matches the received key ID. 2330 * 2331 * 5. Check to see that one or more hashes of the current key ID 2332 * matches the previous key ID or ultimate original key ID 2333 * obtained from the broadcaster or symmetric peer. If no 2334 * match, sit the dance and call for new autokey values. 2335 * 2336 * In case of crypto error, fire the orchestra, stop dancing and 2337 * restart the protocol. 2338 */ 2339 if (peer->flags & FLAG_SKEY) { 2340 /* 2341 * Decrement remaining autokey hashes. This isn't 2342 * perfect if a packet is lost, but results in no harm. 2343 */ 2344 ap = (struct autokey *)peer->recval.ptr; 2345 if (ap != NULL) { 2346 if (ap->seq > 0) 2347 ap->seq--; 2348 } 2349 peer->flash |= TEST8; 2350 rval = crypto_recv(peer, rbufp); 2351 if (rval == XEVNT_OK) { 2352 peer->unreach = 0; 2353 } else { 2354 if (rval == XEVNT_ERR) { 2355 report_event(PEVNT_RESTART, peer, 2356 "crypto error"); 2357 peer_clear(peer, "CRYP"); 2358 peer->flash |= TEST9; /* bad crypt */ 2359 if (peer->flags & FLAG_PREEMPT) { 2360 if (unpeer_crypto_early) { 2361 unpeer(peer); 2362 } 2363 } 2364 } 2365 return; 2366 } 2367 2368 /* 2369 * If server mode, verify the receive key ID matches 2370 * the transmit key ID. 2371 */ 2372 if (hismode == MODE_SERVER) { 2373 if (skeyid == peer->keyid) 2374 peer->flash &= ~TEST8; 2375 2376 /* 2377 * If an extension field is present, verify only that it 2378 * has been correctly signed. We don't need a sequence 2379 * check here, but the sequence continues. 2380 */ 2381 } else if (!(peer->flash & TEST8)) { 2382 peer->pkeyid = skeyid; 2383 2384 /* 2385 * Now the fun part. Here, skeyid is the current ID in 2386 * the packet, pkeyid is the ID in the last packet and 2387 * tkeyid is the hash of skeyid. If the autokey values 2388 * have not been received, this is an automatic error. 2389 * If so, check that the tkeyid matches pkeyid. If not, 2390 * hash tkeyid and try again. If the number of hashes 2391 * exceeds the number remaining in the sequence, declare 2392 * a successful failure and refresh the autokey values. 2393 */ 2394 } else if (ap != NULL) { 2395 int i; 2396 2397 for (i = 0; ; i++) { 2398 if ( tkeyid == peer->pkeyid 2399 || tkeyid == ap->key) { 2400 peer->flash &= ~TEST8; 2401 peer->pkeyid = skeyid; 2402 ap->seq -= i; 2403 break; 2404 } 2405 if (i > ap->seq) { 2406 peer->crypto &= 2407 ~CRYPTO_FLAG_AUTO; 2408 break; 2409 } 2410 tkeyid = session_key( 2411 &rbufp->recv_srcadr, dstadr_sin, 2412 tkeyid, pkeyid, 0); 2413 } 2414 if (peer->flash & TEST8) 2415 report_event(PEVNT_AUTH, peer, "keylist"); 2416 } 2417 if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */ 2418 peer->flash |= TEST8; /* bad autokey */ 2419 2420 /* 2421 * The maximum lifetime of the protocol is about one 2422 * week before restarting the Autokey protocol to 2423 * refresh certificates and leapseconds values. 2424 */ 2425 if (current_time > peer->refresh) { 2426 report_event(PEVNT_RESTART, peer, 2427 "crypto refresh"); 2428 peer_clear(peer, "TIME"); 2429 return; 2430 } 2431 } 2432#endif /* AUTOKEY */ 2433 2434 /* 2435 * The dance is complete and the flash bits have been lit. Toss 2436 * the packet over the fence for processing, which may light up 2437 * more flashers. Leave if the packet is not good. 2438 */ 2439 process_packet(peer, pkt, rbufp->recv_length); 2440 if (peer->flash & PKT_TEST_MASK) 2441 return; 2442 2443 /* [bug 3592] Update poll. Ideally this should not happen in a 2444 * receive branch, but too much is going on here... at least we 2445 * do it only if the packet was good! 2446 */ 2447 poll_update(peer, peer->hpoll, (peer->hmode == MODE_CLIENT)); 2448 2449 /* 2450 * In interleaved mode update the state variables. Also adjust the 2451 * transmit phase to avoid crossover. 2452 */ 2453 if (peer->flip != 0) { 2454 peer->rec = p_rec; 2455 peer->dst = rbufp->recv_time; 2456 if (peer->nextdate - current_time < (1U << min(peer->ppoll, 2457 peer->hpoll)) / 2) 2458 peer->nextdate++; 2459 else 2460 peer->nextdate--; 2461 } 2462} 2463 2464 2465/* 2466 * process_packet - Packet Procedure, a la Section 3.4.4 of RFC-1305 2467 * Or almost, at least. If we're in here we have a reasonable 2468 * expectation that we will be having a long term 2469 * relationship with this host. 2470 */ 2471void 2472process_packet( 2473 register struct peer *peer, 2474 register struct pkt *pkt, 2475 u_int len 2476 ) 2477{ 2478 double t34, t21; 2479 double p_offset, p_del, p_disp; 2480 l_fp p_rec, p_xmt, p_org, p_reftime, ci; 2481 u_char pmode, pleap, pversion, pstratum; 2482 char statstr[NTP_MAXSTRLEN]; 2483#ifdef ASSYM 2484 int itemp; 2485 double etemp, ftemp, td; 2486#endif /* ASSYM */ 2487 2488#if 0 2489 sys_processed++; 2490 peer->processed++; 2491#endif 2492 p_del = FPTOD(NTOHS_FP(pkt->rootdelay)); 2493 p_offset = 0; 2494 p_disp = FPTOD(NTOHS_FP(pkt->rootdisp)); 2495 NTOHL_FP(&pkt->reftime, &p_reftime); 2496 NTOHL_FP(&pkt->org, &p_org); 2497 NTOHL_FP(&pkt->rec, &p_rec); 2498 NTOHL_FP(&pkt->xmt, &p_xmt); 2499 pmode = PKT_MODE(pkt->li_vn_mode); 2500 pleap = PKT_LEAP(pkt->li_vn_mode); 2501 pversion = PKT_VERSION(pkt->li_vn_mode); 2502 pstratum = PKT_TO_STRATUM(pkt->stratum); 2503 2504 /**/ 2505 2506 /**/ 2507 2508 /* 2509 * Verify the server is synchronized; that is, the leap bits, 2510 * stratum and root distance are valid. 2511 */ 2512 if ( pleap == LEAP_NOTINSYNC /* test 6 */ 2513 || pstratum < sys_floor || pstratum >= sys_ceiling) 2514 peer->flash |= TEST6; /* bad synch or strat */ 2515 if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */ 2516 peer->flash |= TEST7; /* bad header */ 2517 2518 /* 2519 * If any tests fail at this point, the packet is discarded. 2520 * Note that some flashers may have already been set in the 2521 * receive() routine. 2522 */ 2523 if (peer->flash & PKT_TEST_MASK) { 2524 peer->seldisptoolarge++; 2525 DPRINTF(1, ("packet: flash header %04x\n", 2526 peer->flash)); 2527 2528 /* ppoll updated? */ 2529 /* XXX: Fuzz the poll? */ 2530 poll_update(peer, peer->hpoll, (peer->hmode == MODE_CLIENT)); 2531 return; 2532 } 2533 2534 /**/ 2535 2536#if 1 2537 sys_processed++; 2538 peer->processed++; 2539#endif 2540 2541 /* 2542 * Capture the header values in the client/peer association.. 2543 */ 2544 record_raw_stats(&peer->srcadr, 2545 peer->dstadr ? &peer->dstadr->sin : NULL, 2546 &p_org, &p_rec, &p_xmt, &peer->dst, 2547 pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision, 2548 p_del, p_disp, pkt->refid, 2549 len - MIN_V4_PKT_LEN, (u_char *)&pkt->exten); 2550 peer->leap = pleap; 2551 peer->stratum = min(pstratum, STRATUM_UNSPEC); 2552 peer->pmode = pmode; 2553 peer->precision = pkt->precision; 2554 peer->rootdelay = p_del; 2555 peer->rootdisp = p_disp; 2556 peer->refid = pkt->refid; /* network byte order */ 2557 peer->reftime = p_reftime; 2558 2559 /* 2560 * First, if either burst mode is armed, enable the burst. 2561 * Compute the headway for the next packet and delay if 2562 * necessary to avoid exceeding the threshold. 2563 */ 2564 if (peer->retry > 0) { 2565 peer->retry = 0; 2566 if (peer->reach) 2567 peer->burst = min(1 << (peer->hpoll - 2568 peer->minpoll), NTP_SHIFT) - 1; 2569 else 2570 peer->burst = NTP_IBURST - 1; 2571 if (peer->burst > 0) 2572 peer->nextdate = current_time; 2573 } 2574 poll_update(peer, peer->hpoll, (peer->hmode == MODE_CLIENT)); 2575 2576 /**/ 2577 2578 /* 2579 * If the peer was previously unreachable, raise a trap. In any 2580 * case, mark it reachable. 2581 */ 2582 if (!peer->reach) { 2583 report_event(PEVNT_REACH, peer, NULL); 2584 peer->timereachable = current_time; 2585 } 2586 peer->reach |= 1; 2587 2588 /* 2589 * For a client/server association, calculate the clock offset, 2590 * roundtrip delay and dispersion. The equations are reordered 2591 * from the spec for more efficient use of temporaries. For a 2592 * broadcast association, offset the last measurement by the 2593 * computed delay during the client/server volley. Note the 2594 * computation of dispersion includes the system precision plus 2595 * that due to the frequency error since the origin time. 2596 * 2597 * It is very important to respect the hazards of overflow. The 2598 * only permitted operation on raw timestamps is subtraction, 2599 * where the result is a signed quantity spanning from 68 years 2600 * in the past to 68 years in the future. To avoid loss of 2601 * precision, these calculations are done using 64-bit integer 2602 * arithmetic. However, the offset and delay calculations are 2603 * sums and differences of these first-order differences, which 2604 * if done using 64-bit integer arithmetic, would be valid over 2605 * only half that span. Since the typical first-order 2606 * differences are usually very small, they are converted to 64- 2607 * bit doubles and all remaining calculations done in floating- 2608 * double arithmetic. This preserves the accuracy while 2609 * retaining the 68-year span. 2610 * 2611 * There are three interleaving schemes, basic, interleaved 2612 * symmetric and interleaved broadcast. The timestamps are 2613 * idioscyncratically different. See the onwire briefing/white 2614 * paper at www.eecis.udel.edu/~mills for details. 2615 * 2616 * Interleaved symmetric mode 2617 * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt, 2618 * t4 = peer->dst 2619 */ 2620 if (peer->flip != 0) { 2621 ci = p_xmt; /* t3 - t4 */ 2622 L_SUB(&ci, &peer->dst); 2623 LFPTOD(&ci, t34); 2624 ci = p_rec; /* t2 - t1 */ 2625 if (peer->flip > 0) 2626 L_SUB(&ci, &peer->borg); 2627 else 2628 L_SUB(&ci, &peer->aorg); 2629 LFPTOD(&ci, t21); 2630 p_del = t21 - t34; 2631 p_offset = (t21 + t34) / 2.; 2632 if (p_del < 0 || p_del > 1.) { 2633 snprintf(statstr, sizeof(statstr), 2634 "t21 %.6f t34 %.6f", t21, t34); 2635 report_event(PEVNT_XERR, peer, statstr); 2636 return; 2637 } 2638 2639 /* 2640 * Broadcast modes 2641 */ 2642 } else if (peer->pmode == MODE_BROADCAST) { 2643 2644 /* 2645 * Interleaved broadcast mode. Use interleaved timestamps. 2646 * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg 2647 */ 2648 if (peer->flags & FLAG_XB) { 2649 ci = p_org; /* delay */ 2650 L_SUB(&ci, &peer->aorg); 2651 LFPTOD(&ci, t34); 2652 ci = p_org; /* t2 - t1 */ 2653 L_SUB(&ci, &peer->borg); 2654 LFPTOD(&ci, t21); 2655 peer->aorg = p_xmt; 2656 peer->borg = peer->dst; 2657 if (t34 < 0 || t34 > 1.) { 2658 /* drop all if in the initial volley */ 2659 if (FLAG_BC_VOL & peer->flags) 2660 goto bcc_init_volley_fail; 2661 snprintf(statstr, sizeof(statstr), 2662 "offset %.6f delay %.6f", t21, t34); 2663 report_event(PEVNT_XERR, peer, statstr); 2664 return; 2665 } 2666 p_offset = t21; 2667 peer->xleave = t34; 2668 2669 /* 2670 * Basic broadcast - use direct timestamps. 2671 * t3 = p_xmt, t4 = peer->dst 2672 */ 2673 } else { 2674 ci = p_xmt; /* t3 - t4 */ 2675 L_SUB(&ci, &peer->dst); 2676 LFPTOD(&ci, t34); 2677 p_offset = t34; 2678 } 2679 2680 /* 2681 * When calibration is complete and the clock is 2682 * synchronized, the bias is calculated as the difference 2683 * between the unicast timestamp and the broadcast 2684 * timestamp. This works for both basic and interleaved 2685 * modes. 2686 * [Bug 3031] Don't keep this peer when the delay 2687 * calculation gives reason to suspect clock steps. 2688 * This is assumed for delays > 50ms. 2689 */ 2690 if (FLAG_BC_VOL & peer->flags) { 2691 peer->flags &= ~FLAG_BC_VOL; 2692 peer->delay = fabs(peer->offset - p_offset) * 2; 2693 DPRINTF(2, ("broadcast volley: initial delay=%.6f\n", 2694 peer->delay)); 2695 if (peer->delay > fabs(sys_bdelay)) { 2696 bcc_init_volley_fail: 2697 DPRINTF(2, ("%s", "broadcast volley: initial delay exceeds limit\n")); 2698 unpeer(peer); 2699 return; 2700 } 2701 } 2702 peer->nextdate = current_time + (1u << peer->ppoll) - 2u; 2703 p_del = peer->delay; 2704 p_offset += p_del / 2; 2705 2706 2707 /* 2708 * Basic mode, otherwise known as the old fashioned way. 2709 * 2710 * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst 2711 */ 2712 } else { 2713 ci = p_xmt; /* t3 - t4 */ 2714 L_SUB(&ci, &peer->dst); 2715 LFPTOD(&ci, t34); 2716 ci = p_rec; /* t2 - t1 */ 2717 L_SUB(&ci, &p_org); 2718 LFPTOD(&ci, t21); 2719 p_del = fabs(t21 - t34); 2720 p_offset = (t21 + t34) / 2.; 2721 } 2722 p_del = max(p_del, LOGTOD(sys_precision)); 2723 p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) + 2724 clock_phi * p_del; 2725 2726#if ASSYM 2727 /* 2728 * This code calculates the outbound and inbound data rates by 2729 * measuring the differences between timestamps at different 2730 * packet lengths. This is helpful in cases of large asymmetric 2731 * delays commonly experienced on deep space communication 2732 * links. 2733 */ 2734 if (peer->t21_last > 0 && peer->t34_bytes > 0) { 2735 itemp = peer->t21_bytes - peer->t21_last; 2736 if (itemp > 25) { 2737 etemp = t21 - peer->t21; 2738 if (fabs(etemp) > 1e-6) { 2739 ftemp = itemp / etemp; 2740 if (ftemp > 1000.) 2741 peer->r21 = ftemp; 2742 } 2743 } 2744 itemp = len - peer->t34_bytes; 2745 if (itemp > 25) { 2746 etemp = -t34 - peer->t34; 2747 if (fabs(etemp) > 1e-6) { 2748 ftemp = itemp / etemp; 2749 if (ftemp > 1000.) 2750 peer->r34 = ftemp; 2751 } 2752 } 2753 } 2754 2755 /* 2756 * The following section compensates for different data rates on 2757 * the outbound (d21) and inbound (t34) directions. To do this, 2758 * it finds t such that r21 * t - r34 * (d - t) = 0, where d is 2759 * the roundtrip delay. Then it calculates the correction as a 2760 * fraction of d. 2761 */ 2762 peer->t21 = t21; 2763 peer->t21_last = peer->t21_bytes; 2764 peer->t34 = -t34; 2765 peer->t34_bytes = len; 2766 DPRINTF(2, ("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21, 2767 peer->t21_bytes, peer->t34, peer->t34_bytes)); 2768 if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) { 2769 if (peer->pmode != MODE_BROADCAST) 2770 td = (peer->r34 / (peer->r21 + peer->r34) - 2771 .5) * p_del; 2772 else 2773 td = 0; 2774 2775 /* 2776 * Unfortunately, in many cases the errors are 2777 * unacceptable, so for the present the rates are not 2778 * used. In future, we might find conditions where the 2779 * calculations are useful, so this should be considered 2780 * a work in progress. 2781 */ 2782 t21 -= td; 2783 t34 -= td; 2784 DPRINTF(2, ("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n", 2785 p_del, peer->r21 / 1e3, peer->r34 / 1e3, 2786 td)); 2787 } 2788#endif /* ASSYM */ 2789 2790 /* 2791 * That was awesome. Now hand off to the clock filter. 2792 */ 2793 clock_filter(peer, p_offset + peer->bias, p_del, p_disp); 2794 2795 /* 2796 * If we are in broadcast calibrate mode, return to broadcast 2797 * client mode when the client is fit and the autokey dance is 2798 * complete. 2799 */ 2800 if ( (FLAG_BC_VOL & peer->flags) 2801 && MODE_CLIENT == peer->hmode 2802 && !(TEST11 & peer_unfit(peer))) { /* distance exceeded */ 2803#ifdef AUTOKEY 2804 if (peer->flags & FLAG_SKEY) { 2805 if (!(~peer->crypto & CRYPTO_FLAG_ALL)) 2806 peer->hmode = MODE_BCLIENT; 2807 } else { 2808 peer->hmode = MODE_BCLIENT; 2809 } 2810#else /* !AUTOKEY follows */ 2811 peer->hmode = MODE_BCLIENT; 2812#endif /* !AUTOKEY */ 2813 } 2814} 2815 2816 2817/* 2818 * clock_update - Called at system process update intervals. 2819 */ 2820static void 2821clock_update( 2822 struct peer *peer /* peer structure pointer */ 2823 ) 2824{ 2825 double dtemp; 2826 l_fp now; 2827#ifdef HAVE_LIBSCF_H 2828 char *fmri; 2829#endif /* HAVE_LIBSCF_H */ 2830 2831 /* 2832 * Update the system state variables. We do this very carefully, 2833 * as the poll interval might need to be clamped differently. 2834 */ 2835 sys_peer = peer; 2836 sys_epoch = peer->epoch; 2837 if (sys_poll < peer->minpoll) 2838 sys_poll = peer->minpoll; 2839 if (sys_poll > peer->maxpoll) 2840 sys_poll = peer->maxpoll; 2841 poll_update(peer, sys_poll, 0); 2842 sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC); 2843 if ( peer->stratum == STRATUM_REFCLOCK 2844 || peer->stratum == STRATUM_UNSPEC) 2845 sys_refid = peer->refid; 2846 else 2847 sys_refid = addr2refid(&peer->srcadr); 2848 /* 2849 * Root Dispersion (E) is defined (in RFC 5905) as: 2850 * 2851 * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA| 2852 * 2853 * where: 2854 * p.epsilon_r is the PollProc's root dispersion 2855 * p.epsilon is the PollProc's dispersion 2856 * p.psi is the PollProc's jitter 2857 * THETA is the combined offset 2858 * 2859 * NB: Think Hard about where these numbers come from and 2860 * what they mean. When did peer->update happen? Has anything 2861 * interesting happened since then? What values are the most 2862 * defensible? Why? 2863 * 2864 * DLM thinks this equation is probably the best of all worse choices. 2865 */ 2866 dtemp = peer->rootdisp 2867 + peer->disp 2868 + sys_jitter 2869 + clock_phi * (current_time - peer->update) 2870 + fabs(sys_offset); 2871 2872 p2_rootdisp = prev_rootdisp; 2873 prev_rootdisp = sys_rootdisp; 2874 if (dtemp > sys_mindisp) 2875 sys_rootdisp = dtemp; 2876 else 2877 sys_rootdisp = sys_mindisp; 2878 2879 sys_rootdelay = peer->delay + peer->rootdelay; 2880 2881 p2_reftime = prev_reftime; 2882 p2_time = prev_time; 2883 2884 prev_reftime = sys_reftime; 2885 prev_time = current_time + 64 + (rand() & 0x3f); /* 64-127 s */ 2886 2887 sys_reftime = peer->dst; 2888 2889 DPRINTF(1, ("clock_update: at %lu sample %lu associd %d\n", 2890 current_time, peer->epoch, peer->associd)); 2891 2892 /* 2893 * Comes now the moment of truth. Crank the clock discipline and 2894 * see what comes out. 2895 */ 2896 switch (local_clock(peer, sys_offset)) { 2897 2898 /* 2899 * Clock exceeds panic threshold. Life as we know it ends. 2900 */ 2901 case -1: 2902#ifdef HAVE_LIBSCF_H 2903 /* 2904 * For Solaris enter the maintenance mode. 2905 */ 2906 if ((fmri = getenv("SMF_FMRI")) != NULL) { 2907 if (smf_maintain_instance(fmri, 0) < 0) { 2908 printf("smf_maintain_instance: %s\n", 2909 scf_strerror(scf_error())); 2910 exit(1); 2911 } 2912 /* 2913 * Sleep until SMF kills us. 2914 */ 2915 for (;;) 2916 pause(); 2917 } 2918#endif /* HAVE_LIBSCF_H */ 2919 exit (-1); 2920 /* not reached */ 2921 2922 /* 2923 * Clock was stepped. Flush all time values of all peers. 2924 */ 2925 case 2: 2926 clear_all(); 2927 set_sys_leap(LEAP_NOTINSYNC); 2928 sys_stratum = STRATUM_UNSPEC; 2929 memcpy(&sys_refid, "STEP", 4); 2930 sys_rootdelay = 0; 2931 p2_rootdisp = 0; 2932 prev_rootdisp = 0; 2933 sys_rootdisp = 0; 2934 L_CLR(&p2_reftime); /* Should we clear p2_reftime? */ 2935 L_CLR(&prev_reftime); /* Should we clear prev_reftime? */ 2936 L_CLR(&sys_reftime); 2937 sys_jitter = LOGTOD(sys_precision); 2938 leapsec_reset_frame(); 2939 break; 2940 2941 /* 2942 * Clock was slewed. Handle the leapsecond stuff. 2943 */ 2944 case 1: 2945 2946 /* 2947 * If this is the first time the clock is set, reset the 2948 * leap bits. If crypto, the timer will goose the setup 2949 * process. 2950 */ 2951 if (sys_leap == LEAP_NOTINSYNC) { 2952 set_sys_leap(LEAP_NOWARNING); 2953#ifdef AUTOKEY 2954 if (crypto_flags) 2955 crypto_update(); 2956#endif /* AUTOKEY */ 2957 /* 2958 * If our parent process is waiting for the 2959 * first clock sync, send them home satisfied. 2960 */ 2961#ifdef HAVE_WORKING_FORK 2962 if (daemon_pipe[1] != -1) { 2963 write(daemon_pipe[1], "S\n", 2); 2964 close(daemon_pipe[1]); 2965 daemon_pipe[1] = -1; 2966 DPRINTF(1, ("notified parent --wait-sync is done\n")); 2967 } 2968#endif /* HAVE_WORKING_FORK */ 2969 2970 } 2971 2972 /* 2973 * If there is no leap second pending and the number of 2974 * survivor leap bits is greater than half the number of 2975 * survivors, try to schedule a leap for the end of the 2976 * current month. (This only works if no leap second for 2977 * that range is in the table, so doing this more than 2978 * once is mostly harmless.) 2979 */ 2980 if (leapsec == LSPROX_NOWARN) { 2981 if ( leap_vote_ins > leap_vote_del 2982 && leap_vote_ins > sys_survivors / 2) { 2983 get_systime(&now); 2984 leapsec_add_dyn(TRUE, now.l_ui, NULL); 2985 } 2986 if ( leap_vote_del > leap_vote_ins 2987 && leap_vote_del > sys_survivors / 2) { 2988 get_systime(&now); 2989 leapsec_add_dyn(FALSE, now.l_ui, NULL); 2990 } 2991 } 2992 break; 2993 2994 /* 2995 * Popcorn spike or step threshold exceeded. Pretend it never 2996 * happened. 2997 */ 2998 default: 2999 break; 3000 } 3001} 3002 3003 3004/* 3005 * poll_update - update peer poll interval 3006 */ 3007void 3008poll_update( 3009 struct peer *peer, /* peer structure pointer */ 3010 u_char mpoll, 3011 u_char skewpoll 3012 ) 3013{ 3014 u_long next, utemp, limit; 3015 u_char hpoll; 3016 3017 /* 3018 * This routine figures out when the next poll should be sent. 3019 * That turns out to be wickedly complicated. One problem is 3020 * that sometimes the time for the next poll is in the past when 3021 * the poll interval is reduced. We watch out for races here 3022 * between the receive process and the poll process. 3023 * 3024 * Clamp the poll interval between minpoll and maxpoll. 3025 */ 3026 hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll); 3027 3028#ifdef AUTOKEY 3029 /* 3030 * If during the crypto protocol the poll interval has changed, 3031 * the lifetimes in the key list are probably bogus. Purge the 3032 * the key list and regenerate it later. 3033 */ 3034 if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll) 3035 key_expire(peer); 3036#endif /* AUTOKEY */ 3037 peer->hpoll = hpoll; 3038 3039 /* 3040 * There are three variables important for poll scheduling, the 3041 * current time (current_time), next scheduled time (nextdate) 3042 * and the earliest time (utemp). The earliest time is 2 s 3043 * seconds, but could be more due to rate management. When 3044 * sending in a burst, use the earliest time. When not in a 3045 * burst but with a reply pending, send at the earliest time 3046 * unless the next scheduled time has not advanced. This can 3047 * only happen if multiple replies are pending in the same 3048 * response interval. Otherwise, send at the later of the next 3049 * scheduled time and the earliest time. 3050 * 3051 * Now we figure out if there is an override. If a burst is in 3052 * progress and we get called from the receive process, just 3053 * slink away. If called from the poll process, delay 1 s for a 3054 * reference clock, otherwise 2 s. 3055 */ 3056 utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) * 3057 (1 << peer->minpoll), ntp_minpkt); 3058 3059 /*[Bug 3592] avoid unlimited postpone of next poll */ 3060 limit = (2u << hpoll); 3061 if (limit > 64) 3062 limit -= (limit >> 2); 3063 limit += peer->outdate; 3064 if (limit < current_time) 3065 limit = current_time; 3066 3067 if (peer->burst > 0) { 3068 if (peer->nextdate > current_time) 3069 return; 3070#ifdef REFCLOCK 3071 else if (peer->flags & FLAG_REFCLOCK) 3072 peer->nextdate = current_time + RESP_DELAY; 3073#endif /* REFCLOCK */ 3074 else 3075 peer->nextdate = utemp; 3076 3077#ifdef AUTOKEY 3078 /* 3079 * If a burst is not in progress and a crypto response message 3080 * is pending, delay 2 s, but only if this is a new interval. 3081 */ 3082 } else if (peer->cmmd != NULL) { 3083 if (peer->nextdate > current_time) { 3084 if (peer->nextdate + ntp_minpkt != utemp) 3085 peer->nextdate = utemp; 3086 } else { 3087 peer->nextdate = utemp; 3088 } 3089#endif /* AUTOKEY */ 3090 3091 /* 3092 * The ordinary case. If a retry, use minpoll; if unreachable, 3093 * use host poll; otherwise, use the minimum of host and peer 3094 * polls; In other words, oversampling is okay but 3095 * understampling is evil. Use the maximum of this value and the 3096 * headway. If the average headway is greater than the headway 3097 * threshold, increase the headway by the minimum interval. 3098 */ 3099 } else { 3100 if (peer->retry > 0) 3101 hpoll = peer->minpoll; 3102 else 3103 hpoll = min(peer->ppoll, peer->hpoll); 3104#ifdef REFCLOCK 3105 if (peer->flags & FLAG_REFCLOCK) 3106 next = 1 << hpoll; 3107 else 3108#endif /* REFCLOCK */ 3109 next = ((0x1000UL | (ntp_random() & 0x0ff)) << 3110 hpoll) >> 12; 3111 next += peer->outdate; 3112 /* XXX: bug3596: Deal with poll skew list? */ 3113 if (skewpoll) { 3114 psl_item psi; 3115 3116 if (0 == get_pollskew(hpoll, &psi)) { 3117 int sub = psi.sub; 3118 int qty = psi.qty; 3119 int msk = psi.msk; 3120 int val; 3121 3122 if ( 0 != sub 3123 || 0 != qty) { 3124 do { 3125 val = ntp_random() & msk; 3126 } while (val > qty); 3127 3128 next -= sub; 3129 next += val; 3130 } 3131 } else { 3132 /* get_pollskew() already logged this */ 3133 } 3134 } 3135 if (next > utemp) 3136 peer->nextdate = next; 3137 else 3138 peer->nextdate = utemp; 3139 if (peer->throttle > (1 << peer->minpoll)) 3140 peer->nextdate += ntp_minpkt; 3141 } 3142 3143 /*[Bug 3592] avoid unlimited postpone of next poll */ 3144 if (peer->nextdate > limit) { 3145 DPRINTF(1, ("poll_update: clamp reached; limit %lu next %lu\n", 3146 limit, peer->nextdate)); 3147 peer->nextdate = limit; 3148 } 3149 DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n", 3150 current_time, ntoa(&peer->srcadr), peer->hpoll, 3151 peer->burst, peer->retry, peer->throttle, 3152 utemp - current_time, peer->nextdate - 3153 current_time)); 3154} 3155 3156 3157/* 3158 * peer_clear - clear peer filter registers. See Section 3.4.8 of the 3159 * spec. 3160 */ 3161void 3162peer_clear( 3163 struct peer *peer, /* peer structure */ 3164 const char *ident /* tally lights */ 3165 ) 3166{ 3167 u_char u; 3168 l_fp bxmt = peer->bxmt; /* bcast clients retain this! */ 3169 3170#ifdef AUTOKEY 3171 /* 3172 * If cryptographic credentials have been acquired, toss them to 3173 * Valhalla. Note that autokeys are ephemeral, in that they are 3174 * tossed immediately upon use. Therefore, the keylist can be 3175 * purged anytime without needing to preserve random keys. Note 3176 * that, if the peer is purged, the cryptographic variables are 3177 * purged, too. This makes it much harder to sneak in some 3178 * unauthenticated data in the clock filter. 3179 */ 3180 key_expire(peer); 3181 if (peer->iffval != NULL) 3182 BN_free(peer->iffval); 3183 value_free(&peer->cookval); 3184 value_free(&peer->recval); 3185 value_free(&peer->encrypt); 3186 value_free(&peer->sndval); 3187 if (peer->cmmd != NULL) 3188 free(peer->cmmd); 3189 if (peer->subject != NULL) 3190 free(peer->subject); 3191 if (peer->issuer != NULL) 3192 free(peer->issuer); 3193#endif /* AUTOKEY */ 3194 3195 /* 3196 * Clear all values, including the optional crypto values above. 3197 */ 3198 memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer)); 3199 peer->ppoll = peer->maxpoll; 3200 peer->hpoll = peer->minpoll; 3201 peer->disp = MAXDISPERSE; 3202 peer->flash = peer_unfit(peer); 3203 peer->jitter = LOGTOD(sys_precision); 3204 3205 /* Don't throw away our broadcast replay protection */ 3206 if (peer->hmode == MODE_BCLIENT) 3207 peer->bxmt = bxmt; 3208 3209 /* 3210 * If interleave mode, initialize the alternate origin switch. 3211 */ 3212 if (peer->flags & FLAG_XLEAVE) 3213 peer->flip = 1; 3214 for (u = 0; u < NTP_SHIFT; u++) { 3215 peer->filter_order[u] = u; 3216 peer->filter_disp[u] = MAXDISPERSE; 3217 } 3218#ifdef REFCLOCK 3219 if (!(peer->flags & FLAG_REFCLOCK)) { 3220#endif 3221 peer->leap = LEAP_NOTINSYNC; 3222 peer->stratum = STRATUM_UNSPEC; 3223 memcpy(&peer->refid, ident, 4); 3224#ifdef REFCLOCK 3225 } else { 3226 /* Clear refclock sample filter */ 3227 peer->procptr->codeproc = 0; 3228 peer->procptr->coderecv = 0; 3229 } 3230#endif 3231 3232 /* 3233 * During initialization use the association count to spread out 3234 * the polls at one-second intervals. Passive associations' 3235 * first poll is delayed by the "discard minimum" to avoid rate 3236 * limiting. Other post-startup new or cleared associations 3237 * randomize the first poll over the minimum poll interval to 3238 * avoid implosion. 3239 */ 3240 peer->nextdate = peer->update = peer->outdate = current_time; 3241 if (initializing) { 3242 peer->nextdate += peer_associations; 3243 } else if (MODE_PASSIVE == peer->hmode) { 3244 peer->nextdate += ntp_minpkt; 3245 } else { 3246 peer->nextdate += ntp_random() % peer->minpoll; 3247 } 3248#ifdef AUTOKEY 3249 peer->refresh = current_time + (1 << NTP_REFRESH); 3250#endif /* AUTOKEY */ 3251 DPRINTF(1, ("peer_clear: at %ld next %ld associd %d refid %s\n", 3252 current_time, peer->nextdate, peer->associd, 3253 ident)); 3254} 3255 3256 3257/* 3258 * clock_filter - add incoming clock sample to filter register and run 3259 * the filter procedure to find the best sample. 3260 */ 3261void 3262clock_filter( 3263 struct peer *peer, /* peer structure pointer */ 3264 double sample_offset, /* clock offset */ 3265 double sample_delay, /* roundtrip delay */ 3266 double sample_disp /* dispersion */ 3267 ) 3268{ 3269 double dst[NTP_SHIFT]; /* distance vector */ 3270 int ord[NTP_SHIFT]; /* index vector */ 3271 int i, j, k, m; 3272 double dtemp, etemp; 3273 char tbuf[80]; 3274 3275 /* 3276 * A sample consists of the offset, delay, dispersion and epoch 3277 * of arrival. The offset and delay are determined by the on- 3278 * wire protocol. The dispersion grows from the last outbound 3279 * packet to the arrival of this one increased by the sum of the 3280 * peer precision and the system precision as required by the 3281 * error budget. First, shift the new arrival into the shift 3282 * register discarding the oldest one. 3283 */ 3284 j = peer->filter_nextpt; 3285 peer->filter_offset[j] = sample_offset; 3286 peer->filter_delay[j] = sample_delay; 3287 peer->filter_disp[j] = sample_disp; 3288 peer->filter_epoch[j] = current_time; 3289 j = (j + 1) % NTP_SHIFT; 3290 peer->filter_nextpt = j; 3291 3292 /* 3293 * Update dispersions since the last update and at the same 3294 * time initialize the distance and index lists. Since samples 3295 * become increasingly uncorrelated beyond the Allan intercept, 3296 * only under exceptional cases will an older sample be used. 3297 * Therefore, the distance list uses a compound metric. If the 3298 * dispersion is greater than the maximum dispersion, clamp the 3299 * distance at that value. If the time since the last update is 3300 * less than the Allan intercept use the delay; otherwise, use 3301 * the sum of the delay and dispersion. 3302 */ 3303 dtemp = clock_phi * (current_time - peer->update); 3304 peer->update = current_time; 3305 for (i = NTP_SHIFT - 1; i >= 0; i--) { 3306 if (i != 0) 3307 peer->filter_disp[j] += dtemp; 3308 if (peer->filter_disp[j] >= MAXDISPERSE) { 3309 peer->filter_disp[j] = MAXDISPERSE; 3310 dst[i] = MAXDISPERSE; 3311 } else if (peer->update - peer->filter_epoch[j] > 3312 (u_long)ULOGTOD(allan_xpt)) { 3313 dst[i] = peer->filter_delay[j] + 3314 peer->filter_disp[j]; 3315 } else { 3316 dst[i] = peer->filter_delay[j]; 3317 } 3318 ord[i] = j; 3319 j = (j + 1) % NTP_SHIFT; 3320 } 3321 3322 /* 3323 * If the clock has stabilized, sort the samples by distance. 3324 */ 3325 if (freq_cnt == 0) { 3326 for (i = 1; i < NTP_SHIFT; i++) { 3327 for (j = 0; j < i; j++) { 3328 if (dst[j] > dst[i]) { 3329 k = ord[j]; 3330 ord[j] = ord[i]; 3331 ord[i] = k; 3332 etemp = dst[j]; 3333 dst[j] = dst[i]; 3334 dst[i] = etemp; 3335 } 3336 } 3337 } 3338 } 3339 3340 /* 3341 * Copy the index list to the association structure so ntpq 3342 * can see it later. Prune the distance list to leave only 3343 * samples less than the maximum dispersion, which disfavors 3344 * uncorrelated samples older than the Allan intercept. To 3345 * further improve the jitter estimate, of the remainder leave 3346 * only samples less than the maximum distance, but keep at 3347 * least two samples for jitter calculation. 3348 */ 3349 m = 0; 3350 for (i = 0; i < NTP_SHIFT; i++) { 3351 peer->filter_order[i] = (u_char) ord[i]; 3352 if ( dst[i] >= MAXDISPERSE 3353 || (m >= 2 && dst[i] >= sys_maxdist)) 3354 continue; 3355 m++; 3356 } 3357 3358 /* 3359 * Compute the dispersion and jitter. The dispersion is weighted 3360 * exponentially by NTP_FWEIGHT (0.5) so it is normalized close 3361 * to 1.0. The jitter is the RMS differences relative to the 3362 * lowest delay sample. 3363 */ 3364 peer->disp = peer->jitter = 0; 3365 k = ord[0]; 3366 for (i = NTP_SHIFT - 1; i >= 0; i--) { 3367 j = ord[i]; 3368 peer->disp = NTP_FWEIGHT * (peer->disp + 3369 peer->filter_disp[j]); 3370 if (i < m) 3371 peer->jitter += DIFF(peer->filter_offset[j], 3372 peer->filter_offset[k]); 3373 } 3374 3375 /* 3376 * If no acceptable samples remain in the shift register, 3377 * quietly tiptoe home leaving only the dispersion. Otherwise, 3378 * save the offset, delay and jitter. Note the jitter must not 3379 * be less than the precision. 3380 */ 3381 if (m == 0) { 3382 clock_select(); 3383 return; 3384 } 3385 etemp = fabs(peer->offset - peer->filter_offset[k]); 3386 peer->offset = peer->filter_offset[k]; 3387 peer->delay = peer->filter_delay[k]; 3388 if (m > 1) 3389 peer->jitter /= m - 1; 3390 peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision)); 3391 3392 /* 3393 * If the the new sample and the current sample are both valid 3394 * and the difference between their offsets exceeds CLOCK_SGATE 3395 * (3) times the jitter and the interval between them is less 3396 * than twice the host poll interval, consider the new sample 3397 * a popcorn spike and ignore it. 3398 */ 3399 if ( peer->disp < sys_maxdist 3400 && peer->filter_disp[k] < sys_maxdist 3401 && etemp > CLOCK_SGATE * peer->jitter 3402 && peer->filter_epoch[k] - peer->epoch 3403 < 2. * ULOGTOD(peer->hpoll)) { 3404 snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp); 3405 report_event(PEVNT_POPCORN, peer, tbuf); 3406 return; 3407 } 3408 3409 /* 3410 * A new minimum sample is useful only if it is later than the 3411 * last one used. In this design the maximum lifetime of any 3412 * sample is not greater than eight times the poll interval, so 3413 * the maximum interval between minimum samples is eight 3414 * packets. 3415 */ 3416 if (peer->filter_epoch[k] <= peer->epoch) { 3417 DPRINTF(2, ("clock_filter: old sample %lu\n", current_time - 3418 peer->filter_epoch[k])); 3419 return; 3420 } 3421 peer->epoch = peer->filter_epoch[k]; 3422 3423 /* 3424 * The mitigated sample statistics are saved for later 3425 * processing. If not synchronized or not in a burst, tickle the 3426 * clock select algorithm. 3427 */ 3428 record_peer_stats(&peer->srcadr, ctlpeerstatus(peer), 3429 peer->offset, peer->delay, peer->disp, peer->jitter); 3430 DPRINTF(1, ("clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n", 3431 m, peer->offset, peer->delay, peer->disp, 3432 peer->jitter)); 3433 if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC) 3434 clock_select(); 3435} 3436 3437 3438/* 3439 * clock_select - find the pick-of-the-litter clock 3440 * 3441 * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always 3442 * be enabled, even if declared falseticker, (2) only the prefer peer 3443 * can be selected as the system peer, (3) if the external source is 3444 * down, the system leap bits are set to 11 and the stratum set to 3445 * infinity. 3446 */ 3447void 3448clock_select(void) 3449{ 3450 struct peer *peer; 3451 int i, j, k, n; 3452 int nlist, nl2; 3453 int allow; 3454 int speer; 3455 double d, e, f, g; 3456 double high, low; 3457 double speermet; 3458 double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */ 3459 struct endpoint endp; 3460 struct peer *osys_peer; 3461 struct peer *sys_prefer = NULL; /* prefer peer */ 3462 struct peer *typesystem = NULL; 3463 struct peer *typeorphan = NULL; 3464#ifdef REFCLOCK 3465 struct peer *typeacts = NULL; 3466 struct peer *typelocal = NULL; 3467 struct peer *typepps = NULL; 3468#endif /* REFCLOCK */ 3469 static struct endpoint *endpoint = NULL; 3470 static int *indx = NULL; 3471 static peer_select *peers = NULL; 3472 static u_int endpoint_size = 0; 3473 static u_int peers_size = 0; 3474 static u_int indx_size = 0; 3475 size_t octets; 3476 3477 /* 3478 * Initialize and create endpoint, index and peer lists big 3479 * enough to handle all associations. 3480 */ 3481 osys_peer = sys_peer; 3482 sys_survivors = 0; 3483#ifdef LOCKCLOCK 3484 set_sys_leap(LEAP_NOTINSYNC); 3485 sys_stratum = STRATUM_UNSPEC; 3486 memcpy(&sys_refid, "DOWN", 4); 3487#endif /* LOCKCLOCK */ 3488 3489 /* 3490 * Allocate dynamic space depending on the number of 3491 * associations. 3492 */ 3493 nlist = 1; 3494 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3495 nlist++; 3496 endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint)); 3497 peers_size = ALIGNED_SIZE(nlist * sizeof(*peers)); 3498 indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx)); 3499 octets = endpoint_size + peers_size + indx_size; 3500 endpoint = erealloc(endpoint, octets); 3501 peers = INC_ALIGNED_PTR(endpoint, endpoint_size); 3502 indx = INC_ALIGNED_PTR(peers, peers_size); 3503 3504 /* 3505 * Initially, we populate the island with all the rifraff peers 3506 * that happen to be lying around. Those with seriously 3507 * defective clocks are immediately booted off the island. Then, 3508 * the falsetickers are culled and put to sea. The truechimers 3509 * remaining are subject to repeated rounds where the most 3510 * unpopular at each round is kicked off. When the population 3511 * has dwindled to sys_minclock, the survivors split a million 3512 * bucks and collectively crank the chimes. 3513 */ 3514 nlist = nl2 = 0; /* none yet */ 3515 for (peer = peer_list; peer != NULL; peer = peer->p_link) { 3516 peer->new_status = CTL_PST_SEL_REJECT; 3517 3518 /* 3519 * Leave the island immediately if the peer is 3520 * unfit to synchronize. 3521 */ 3522 if (peer_unfit(peer)) { 3523 continue; 3524 } 3525 3526 /* 3527 * If this peer is an orphan parent, elect the 3528 * one with the lowest metric defined as the 3529 * IPv4 address or the first 64 bits of the 3530 * hashed IPv6 address. To ensure convergence 3531 * on the same selected orphan, consider as 3532 * well that this system may have the lowest 3533 * metric and be the orphan parent. If this 3534 * system wins, sys_peer will be NULL to trigger 3535 * orphan mode in timer(). 3536 */ 3537 if (peer->stratum == sys_orphan) { 3538 u_int32 localmet; 3539 u_int32 peermet; 3540 3541 if (peer->dstadr != NULL) 3542 localmet = ntohl(peer->dstadr->addr_refid); 3543 else 3544 localmet = U_INT32_MAX; 3545 peermet = ntohl(addr2refid(&peer->srcadr)); 3546 if (peermet < localmet && peermet < orphmet) { 3547 typeorphan = peer; 3548 orphmet = peermet; 3549 } 3550 continue; 3551 } 3552 3553 /* 3554 * If this peer could have the orphan parent 3555 * as a synchronization ancestor, exclude it 3556 * from selection to avoid forming a 3557 * synchronization loop within the orphan mesh, 3558 * triggering stratum climb to infinity 3559 * instability. Peers at stratum higher than 3560 * the orphan stratum could have the orphan 3561 * parent in ancestry so are excluded. 3562 * See http://bugs.ntp.org/2050 3563 */ 3564 if (peer->stratum > sys_orphan) { 3565 continue; 3566 } 3567#ifdef REFCLOCK 3568 /* 3569 * The following are special cases. We deal 3570 * with them later. 3571 */ 3572 if (!(peer->flags & FLAG_PREFER)) { 3573 switch (peer->refclktype) { 3574 case REFCLK_LOCALCLOCK: 3575 if ( current_time > orphwait 3576 && typelocal == NULL) 3577 typelocal = peer; 3578 continue; 3579 3580 case REFCLK_ACTS: 3581 if ( current_time > orphwait 3582 && typeacts == NULL) 3583 typeacts = peer; 3584 continue; 3585 } 3586 } 3587#endif /* REFCLOCK */ 3588 3589 /* 3590 * If we get this far, the peer can stay on the 3591 * island, but does not yet have the immunity 3592 * idol. 3593 */ 3594 peer->new_status = CTL_PST_SEL_SANE; 3595 f = root_distance(peer); 3596 peers[nlist].peer = peer; 3597 peers[nlist].error = peer->jitter; 3598 peers[nlist].synch = f; 3599 nlist++; 3600 3601 /* 3602 * Insert each interval endpoint on the unsorted 3603 * endpoint[] list. 3604 */ 3605 e = peer->offset; 3606 endpoint[nl2].type = -1; /* lower end */ 3607 endpoint[nl2].val = e - f; 3608 nl2++; 3609 endpoint[nl2].type = 1; /* upper end */ 3610 endpoint[nl2].val = e + f; 3611 nl2++; 3612 } 3613 /* 3614 * Construct sorted indx[] of endpoint[] indexes ordered by 3615 * offset. 3616 */ 3617 for (i = 0; i < nl2; i++) 3618 indx[i] = i; 3619 for (i = 0; i < nl2; i++) { 3620 endp = endpoint[indx[i]]; 3621 e = endp.val; 3622 k = i; 3623 for (j = i + 1; j < nl2; j++) { 3624 endp = endpoint[indx[j]]; 3625 if (endp.val < e) { 3626 e = endp.val; 3627 k = j; 3628 } 3629 } 3630 if (k != i) { 3631 j = indx[k]; 3632 indx[k] = indx[i]; 3633 indx[i] = j; 3634 } 3635 } 3636 for (i = 0; i < nl2; i++) 3637 DPRINTF(3, ("select: endpoint %2d %.6f\n", 3638 endpoint[indx[i]].type, endpoint[indx[i]].val)); 3639 3640 /* 3641 * This is the actual algorithm that cleaves the truechimers 3642 * from the falsetickers. The original algorithm was described 3643 * in Keith Marzullo's dissertation, but has been modified for 3644 * better accuracy. 3645 * 3646 * Briefly put, we first assume there are no falsetickers, then 3647 * scan the candidate list first from the low end upwards and 3648 * then from the high end downwards. The scans stop when the 3649 * number of intersections equals the number of candidates less 3650 * the number of falsetickers. If this doesn't happen for a 3651 * given number of falsetickers, we bump the number of 3652 * falsetickers and try again. If the number of falsetickers 3653 * becomes equal to or greater than half the number of 3654 * candidates, the Albanians have won the Byzantine wars and 3655 * correct synchronization is not possible. 3656 * 3657 * Here, nlist is the number of candidates and allow is the 3658 * number of falsetickers. Upon exit, the truechimers are the 3659 * survivors with offsets not less than low and not greater than 3660 * high. There may be none of them. 3661 */ 3662 low = 1e9; 3663 high = -1e9; 3664 for (allow = 0; 2 * allow < nlist; allow++) { 3665 3666 /* 3667 * Bound the interval (low, high) as the smallest 3668 * interval containing points from the most sources. 3669 */ 3670 n = 0; 3671 for (i = 0; i < nl2; i++) { 3672 low = endpoint[indx[i]].val; 3673 n -= endpoint[indx[i]].type; 3674 if (n >= nlist - allow) 3675 break; 3676 } 3677 n = 0; 3678 for (j = nl2 - 1; j >= 0; j--) { 3679 high = endpoint[indx[j]].val; 3680 n += endpoint[indx[j]].type; 3681 if (n >= nlist - allow) 3682 break; 3683 } 3684 3685 /* 3686 * If an interval containing truechimers is found, stop. 3687 * If not, increase the number of falsetickers and go 3688 * around again. 3689 */ 3690 if (high > low) 3691 break; 3692 } 3693 3694 /* 3695 * Clustering algorithm. Whittle candidate list of falsetickers, 3696 * who leave the island immediately. The TRUE peer is always a 3697 * truechimer. We must leave at least one peer to collect the 3698 * million bucks. 3699 * 3700 * We assert the correct time is contained in the interval, but 3701 * the best offset estimate for the interval might not be 3702 * contained in the interval. For this purpose, a truechimer is 3703 * defined as the midpoint of an interval that overlaps the 3704 * intersection interval. 3705 */ 3706 j = 0; 3707 for (i = 0; i < nlist; i++) { 3708 double h; 3709 3710 peer = peers[i].peer; 3711 h = peers[i].synch; 3712 if (( high <= low 3713 || peer->offset + h < low 3714 || peer->offset - h > high 3715 ) && !(peer->flags & FLAG_TRUE)) 3716 continue; 3717 3718#ifdef REFCLOCK 3719 /* 3720 * Eligible PPS peers must survive the intersection 3721 * algorithm. Use the first one found, but don't 3722 * include any of them in the cluster population. 3723 */ 3724 if (peer->flags & FLAG_PPS) { 3725 if (typepps == NULL) 3726 typepps = peer; 3727 if (!(peer->flags & FLAG_TSTAMP_PPS)) 3728 continue; 3729 } 3730#endif /* REFCLOCK */ 3731 3732 if (j != i) 3733 peers[j] = peers[i]; 3734 j++; 3735 } 3736 nlist = j; 3737 3738 /* 3739 * If no survivors remain at this point, check if the modem 3740 * driver, local driver or orphan parent in that order. If so, 3741 * nominate the first one found as the only survivor. 3742 * Otherwise, give up and leave the island to the rats. 3743 */ 3744 if (nlist == 0) { 3745 peers[0].error = 0; 3746 peers[0].synch = sys_mindisp; 3747#ifdef REFCLOCK 3748 if (typeacts != NULL) { 3749 peers[0].peer = typeacts; 3750 nlist = 1; 3751 } else if (typelocal != NULL) { 3752 peers[0].peer = typelocal; 3753 nlist = 1; 3754 } else 3755#endif /* REFCLOCK */ 3756 if (typeorphan != NULL) { 3757 peers[0].peer = typeorphan; 3758 nlist = 1; 3759 } 3760 } 3761 3762 /* 3763 * Mark the candidates at this point as truechimers. 3764 */ 3765 for (i = 0; i < nlist; i++) { 3766 peers[i].peer->new_status = CTL_PST_SEL_SELCAND; 3767 DPRINTF(2, ("select: survivor %s %f\n", 3768 stoa(&peers[i].peer->srcadr), peers[i].synch)); 3769 } 3770 3771 /* 3772 * Now, vote outliers off the island by select jitter weighted 3773 * by root distance. Continue voting as long as there are more 3774 * than sys_minclock survivors and the select jitter of the peer 3775 * with the worst metric is greater than the minimum peer 3776 * jitter. Stop if we are about to discard a TRUE or PREFER 3777 * peer, who of course have the immunity idol. 3778 */ 3779 while (1) { 3780 d = 1e9; 3781 e = -1e9; 3782 g = 0; 3783 k = 0; 3784 for (i = 0; i < nlist; i++) { 3785 if (peers[i].error < d) 3786 d = peers[i].error; 3787 peers[i].seljit = 0; 3788 if (nlist > 1) { 3789 f = 0; 3790 for (j = 0; j < nlist; j++) 3791 f += DIFF(peers[j].peer->offset, 3792 peers[i].peer->offset); 3793 peers[i].seljit = SQRT(f / (nlist - 1)); 3794 } 3795 if (peers[i].seljit * peers[i].synch > e) { 3796 g = peers[i].seljit; 3797 e = peers[i].seljit * peers[i].synch; 3798 k = i; 3799 } 3800 } 3801 g = max(g, LOGTOD(sys_precision)); 3802 if ( nlist <= max(1, sys_minclock) 3803 || g <= d 3804 || ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags)) 3805 break; 3806 3807 DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n", 3808 ntoa(&peers[k].peer->srcadr), g, d)); 3809 if (nlist > sys_maxclock) 3810 peers[k].peer->new_status = CTL_PST_SEL_EXCESS; 3811 for (j = k + 1; j < nlist; j++) 3812 peers[j - 1] = peers[j]; 3813 nlist--; 3814 } 3815 3816 /* 3817 * What remains is a list usually not greater than sys_minclock 3818 * peers. Note that unsynchronized peers cannot survive this 3819 * far. Count and mark these survivors. 3820 * 3821 * While at it, count the number of leap warning bits found. 3822 * This will be used later to vote the system leap warning bit. 3823 * If a leap warning bit is found on a reference clock, the vote 3824 * is always won. 3825 * 3826 * Choose the system peer using a hybrid metric composed of the 3827 * selection jitter scaled by the root distance augmented by 3828 * stratum scaled by sys_mindisp (.001 by default). The goal of 3829 * the small stratum factor is to avoid clockhop between a 3830 * reference clock and a network peer which has a refclock and 3831 * is using an older ntpd, which does not floor sys_rootdisp at 3832 * sys_mindisp. 3833 * 3834 * In contrast, ntpd 4.2.6 and earlier used stratum primarily 3835 * in selecting the system peer, using a weight of 1 second of 3836 * additional root distance per stratum. This heavy bias is no 3837 * longer appropriate, as the scaled root distance provides a 3838 * more rational metric carrying the cumulative error budget. 3839 */ 3840 e = 1e9; 3841 speer = 0; 3842 leap_vote_ins = 0; 3843 leap_vote_del = 0; 3844 for (i = 0; i < nlist; i++) { 3845 peer = peers[i].peer; 3846 peer->unreach = 0; 3847 peer->new_status = CTL_PST_SEL_SYNCCAND; 3848 sys_survivors++; 3849 if (peer->leap == LEAP_ADDSECOND) { 3850 if (peer->flags & FLAG_REFCLOCK) 3851 leap_vote_ins = nlist; 3852 else if (leap_vote_ins < nlist) 3853 leap_vote_ins++; 3854 } 3855 if (peer->leap == LEAP_DELSECOND) { 3856 if (peer->flags & FLAG_REFCLOCK) 3857 leap_vote_del = nlist; 3858 else if (leap_vote_del < nlist) 3859 leap_vote_del++; 3860 } 3861 if (peer->flags & FLAG_PREFER) 3862 sys_prefer = peer; 3863 speermet = peers[i].seljit * peers[i].synch + 3864 peer->stratum * sys_mindisp; 3865 if (speermet < e) { 3866 e = speermet; 3867 speer = i; 3868 } 3869 } 3870 3871 /* 3872 * Unless there are at least sys_misane survivors, leave the 3873 * building dark. Otherwise, do a clockhop dance. Ordinarily, 3874 * use the selected survivor speer. However, if the current 3875 * system peer is not speer, stay with the current system peer 3876 * as long as it doesn't get too old or too ugly. 3877 */ 3878 if (nlist > 0 && nlist >= sys_minsane) { 3879 double x; 3880 3881 typesystem = peers[speer].peer; 3882 if (osys_peer == NULL || osys_peer == typesystem) { 3883 sys_clockhop = 0; 3884 } else if ((x = fabs(typesystem->offset - 3885 osys_peer->offset)) < sys_mindisp) { 3886 if (sys_clockhop == 0) 3887 sys_clockhop = sys_mindisp; 3888 else 3889 sys_clockhop *= .5; 3890 DPRINTF(1, ("select: clockhop %d %.6f %.6f\n", 3891 j, x, sys_clockhop)); 3892 if (fabs(x) < sys_clockhop) 3893 typesystem = osys_peer; 3894 else 3895 sys_clockhop = 0; 3896 } else { 3897 sys_clockhop = 0; 3898 } 3899 } 3900 3901 /* 3902 * Mitigation rules of the game. We have the pick of the 3903 * litter in typesystem if any survivors are left. If 3904 * there is a prefer peer, use its offset and jitter. 3905 * Otherwise, use the combined offset and jitter of all kitters. 3906 */ 3907 if (typesystem != NULL) { 3908 if (sys_prefer == NULL) { 3909 typesystem->new_status = CTL_PST_SEL_SYSPEER; 3910 clock_combine(peers, sys_survivors, speer); 3911 } else { 3912 typesystem = sys_prefer; 3913 sys_clockhop = 0; 3914 typesystem->new_status = CTL_PST_SEL_SYSPEER; 3915 sys_offset = typesystem->offset; 3916 sys_jitter = typesystem->jitter; 3917 } 3918 DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n", 3919 sys_offset, sys_jitter)); 3920 } 3921#ifdef REFCLOCK 3922 /* 3923 * If a PPS driver is lit and the combined offset is less than 3924 * 0.4 s, select the driver as the PPS peer and use its offset 3925 * and jitter. However, if this is the atom driver, use it only 3926 * if there is a prefer peer or there are no survivors and none 3927 * are required. 3928 */ 3929 if ( typepps != NULL 3930 && fabs(sys_offset) < 0.4 3931 && ( typepps->refclktype != REFCLK_ATOM_PPS 3932 || ( typepps->refclktype == REFCLK_ATOM_PPS 3933 && ( sys_prefer != NULL 3934 || (typesystem == NULL && sys_minsane == 0))))) { 3935 typesystem = typepps; 3936 sys_clockhop = 0; 3937 typesystem->new_status = CTL_PST_SEL_PPS; 3938 sys_offset = typesystem->offset; 3939 sys_jitter = typesystem->jitter; 3940 DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n", 3941 sys_offset, sys_jitter)); 3942 } 3943#endif /* REFCLOCK */ 3944 3945 /* 3946 * If there are no survivors at this point, there is no 3947 * system peer. If so and this is an old update, keep the 3948 * current statistics, but do not update the clock. 3949 */ 3950 if (typesystem == NULL) { 3951 if (osys_peer != NULL) { 3952 if (sys_orphwait > 0) 3953 orphwait = current_time + sys_orphwait; 3954 report_event(EVNT_NOPEER, NULL, NULL); 3955 } 3956 sys_peer = NULL; 3957 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3958 peer->status = peer->new_status; 3959 return; 3960 } 3961 3962 /* 3963 * Do not use old data, as this may mess up the clock discipline 3964 * stability. 3965 */ 3966 if (typesystem->epoch <= sys_epoch) 3967 return; 3968 3969 /* 3970 * We have found the alpha male. Wind the clock. 3971 */ 3972 if (osys_peer != typesystem) 3973 report_event(PEVNT_NEWPEER, typesystem, NULL); 3974 for (peer = peer_list; peer != NULL; peer = peer->p_link) 3975 peer->status = peer->new_status; 3976 clock_update(typesystem); 3977} 3978 3979 3980static void 3981clock_combine( 3982 peer_select * peers, /* survivor list */ 3983 int npeers, /* number of survivors */ 3984 int syspeer /* index of sys.peer */ 3985 ) 3986{ 3987 int i; 3988 double x, y, z, w; 3989 3990 y = z = w = 0; 3991 for (i = 0; i < npeers; i++) { 3992 x = 1. / peers[i].synch; 3993 y += x; 3994 z += x * peers[i].peer->offset; 3995 w += x * DIFF(peers[i].peer->offset, 3996 peers[syspeer].peer->offset); 3997 } 3998 sys_offset = z / y; 3999 sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit)); 4000} 4001 4002 4003/* 4004 * root_distance - compute synchronization distance from peer to root 4005 */ 4006static double 4007root_distance( 4008 struct peer *peer /* peer structure pointer */ 4009 ) 4010{ 4011 double dtemp; 4012 4013 /* 4014 * Root Distance (LAMBDA) is defined as: 4015 * (delta + DELTA)/2 + epsilon + EPSILON + D 4016 * 4017 * where: 4018 * delta is the round-trip delay 4019 * DELTA is the root delay 4020 * epsilon is the peer dispersion 4021 * + (15 usec each second) 4022 * EPSILON is the root dispersion 4023 * D is sys_jitter 4024 * 4025 * NB: Think hard about why we are using these values, and what 4026 * the alternatives are, and the various pros/cons. 4027 * 4028 * DLM thinks these are probably the best choices from any of the 4029 * other worse choices. 4030 */ 4031 dtemp = (peer->delay + peer->rootdelay) / 2 4032 + peer->disp 4033 + clock_phi * (current_time - peer->update) 4034 + peer->rootdisp 4035 + peer->jitter; 4036 /* 4037 * Careful squeak here. The value returned must be greater than 4038 * the minimum root dispersion in order to avoid clockhop with 4039 * highly precise reference clocks. Note that the root distance 4040 * cannot exceed the sys_maxdist, as this is the cutoff by the 4041 * selection algorithm. 4042 */ 4043 if (dtemp < sys_mindisp) 4044 dtemp = sys_mindisp; 4045 return (dtemp); 4046} 4047 4048 4049/* 4050 * peer_xmit - send packet for persistent association. 4051 */ 4052static void 4053peer_xmit( 4054 struct peer *peer /* peer structure pointer */ 4055 ) 4056{ 4057 struct pkt xpkt; /* transmit packet */ 4058 size_t sendlen, authlen; 4059 keyid_t xkeyid = 0; /* transmit key ID */ 4060 l_fp xmt_tx, xmt_ty; 4061 4062 if (!peer->dstadr) /* drop peers without interface */ 4063 return; 4064 4065 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version, 4066 peer->hmode); 4067 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 4068 xpkt.ppoll = peer->hpoll; 4069 xpkt.precision = sys_precision; 4070 xpkt.refid = sys_refid; 4071 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 4072 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); 4073 /* Use sys_reftime for peer exchanges */ 4074 HTONL_FP(&sys_reftime, &xpkt.reftime); 4075 HTONL_FP(&peer->rec, &xpkt.org); 4076 HTONL_FP(&peer->dst, &xpkt.rec); 4077 4078 /* 4079 * If the received packet contains a MAC, the transmitted packet 4080 * is authenticated and contains a MAC. If not, the transmitted 4081 * packet is not authenticated. 4082 * 4083 * It is most important when autokey is in use that the local 4084 * interface IP address be known before the first packet is 4085 * sent. Otherwise, it is not possible to compute a correct MAC 4086 * the recipient will accept. Thus, the I/O semantics have to do 4087 * a little more work. In particular, the wildcard interface 4088 * might not be usable. 4089 */ 4090 sendlen = LEN_PKT_NOMAC; 4091 if ( 4092#ifdef AUTOKEY 4093 !(peer->flags & FLAG_SKEY) && 4094#endif /* !AUTOKEY */ 4095 peer->keyid == 0) { 4096 4097 /* 4098 * Transmit a-priori timestamps 4099 */ 4100 get_systime(&xmt_tx); 4101 if (peer->flip == 0) { /* basic mode */ 4102 peer->aorg = xmt_tx; 4103 HTONL_FP(&xmt_tx, &xpkt.xmt); 4104 } else { /* interleaved modes */ 4105 if (peer->hmode == MODE_BROADCAST) { /* bcst */ 4106 HTONL_FP(&xmt_tx, &xpkt.xmt); 4107 if (peer->flip > 0) 4108 HTONL_FP(&peer->borg, 4109 &xpkt.org); 4110 else 4111 HTONL_FP(&peer->aorg, 4112 &xpkt.org); 4113 } else { /* symmetric */ 4114 if (peer->flip > 0) 4115 HTONL_FP(&peer->borg, 4116 &xpkt.xmt); 4117 else 4118 HTONL_FP(&peer->aorg, 4119 &xpkt.xmt); 4120 } 4121 } 4122 peer->t21_bytes = sendlen; 4123 sendpkt(&peer->srcadr, peer->dstadr, 4124 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl], 4125 &xpkt, sendlen); 4126 peer->sent++; 4127 peer->throttle += (1 << peer->minpoll) - 2; 4128 4129 /* 4130 * Capture a-posteriori timestamps 4131 */ 4132 get_systime(&xmt_ty); 4133 if (peer->flip != 0) { /* interleaved modes */ 4134 if (peer->flip > 0) 4135 peer->aorg = xmt_ty; 4136 else 4137 peer->borg = xmt_ty; 4138 peer->flip = -peer->flip; 4139 } 4140 L_SUB(&xmt_ty, &xmt_tx); 4141 LFPTOD(&xmt_ty, peer->xleave); 4142 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d len %zu xmt %#010x.%08x\n", 4143 current_time, 4144 peer->dstadr ? stoa(&peer->dstadr->sin) : "-", 4145 stoa(&peer->srcadr), peer->hmode, sendlen, 4146 xmt_tx.l_ui, xmt_tx.l_uf)); 4147 return; 4148 } 4149 4150 /* 4151 * Authentication is enabled, so the transmitted packet must be 4152 * authenticated. If autokey is enabled, fuss with the various 4153 * modes; otherwise, symmetric key cryptography is used. 4154 */ 4155#ifdef AUTOKEY 4156 if (peer->flags & FLAG_SKEY) { 4157 struct exten *exten; /* extension field */ 4158 4159 /* 4160 * The Public Key Dance (PKD): Cryptographic credentials 4161 * are contained in extension fields, each including a 4162 * 4-octet length/code word followed by a 4-octet 4163 * association ID and optional additional data. Optional 4164 * data includes a 4-octet data length field followed by 4165 * the data itself. Request messages are sent from a 4166 * configured association; response messages can be sent 4167 * from a configured association or can take the fast 4168 * path without ever matching an association. Response 4169 * messages have the same code as the request, but have 4170 * a response bit and possibly an error bit set. In this 4171 * implementation, a message may contain no more than 4172 * one command and one or more responses. 4173 * 4174 * Cryptographic session keys include both a public and 4175 * a private componet. Request and response messages 4176 * using extension fields are always sent with the 4177 * private component set to zero. Packets without 4178 * extension fields indlude the private component when 4179 * the session key is generated. 4180 */ 4181 while (1) { 4182 4183 /* 4184 * Allocate and initialize a keylist if not 4185 * already done. Then, use the list in inverse 4186 * order, discarding keys once used. Keep the 4187 * latest key around until the next one, so 4188 * clients can use client/server packets to 4189 * compute propagation delay. 4190 * 4191 * Note that once a key is used from the list, 4192 * it is retained in the key cache until the 4193 * next key is used. This is to allow a client 4194 * to retrieve the encrypted session key 4195 * identifier to verify authenticity. 4196 * 4197 * If for some reason a key is no longer in the 4198 * key cache, a birthday has happened or the key 4199 * has expired, so the pseudo-random sequence is 4200 * broken. In that case, purge the keylist and 4201 * regenerate it. 4202 */ 4203 if (peer->keynumber == 0) 4204 make_keylist(peer, peer->dstadr); 4205 else 4206 peer->keynumber--; 4207 xkeyid = peer->keylist[peer->keynumber]; 4208 if (authistrusted(xkeyid)) 4209 break; 4210 else 4211 key_expire(peer); 4212 } 4213 peer->keyid = xkeyid; 4214 exten = NULL; 4215 switch (peer->hmode) { 4216 4217 /* 4218 * In broadcast server mode the autokey values are 4219 * required by the broadcast clients. Push them when a 4220 * new keylist is generated; otherwise, push the 4221 * association message so the client can request them at 4222 * other times. 4223 */ 4224 case MODE_BROADCAST: 4225 if (peer->flags & FLAG_ASSOC) 4226 exten = crypto_args(peer, CRYPTO_AUTO | 4227 CRYPTO_RESP, peer->associd, NULL); 4228 else 4229 exten = crypto_args(peer, CRYPTO_ASSOC | 4230 CRYPTO_RESP, peer->associd, NULL); 4231 break; 4232 4233 /* 4234 * In symmetric modes the parameter, certificate, 4235 * identity, cookie and autokey exchanges are 4236 * required. The leapsecond exchange is optional. But, a 4237 * peer will not believe the other peer until the other 4238 * peer has synchronized, so the certificate exchange 4239 * might loop until then. If a peer finds a broken 4240 * autokey sequence, it uses the autokey exchange to 4241 * retrieve the autokey values. In any case, if a new 4242 * keylist is generated, the autokey values are pushed. 4243 */ 4244 case MODE_ACTIVE: 4245 case MODE_PASSIVE: 4246 4247 /* 4248 * Parameter, certificate and identity. 4249 */ 4250 if (!peer->crypto) 4251 exten = crypto_args(peer, CRYPTO_ASSOC, 4252 peer->associd, hostval.ptr); 4253 else if (!(peer->crypto & CRYPTO_FLAG_CERT)) 4254 exten = crypto_args(peer, CRYPTO_CERT, 4255 peer->associd, peer->issuer); 4256 else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) 4257 exten = crypto_args(peer, 4258 crypto_ident(peer), peer->associd, 4259 NULL); 4260 4261 /* 4262 * Cookie and autokey. We request the cookie 4263 * only when the this peer and the other peer 4264 * are synchronized. But, this peer needs the 4265 * autokey values when the cookie is zero. Any 4266 * time we regenerate the key list, we offer the 4267 * autokey values without being asked. If for 4268 * some reason either peer finds a broken 4269 * autokey sequence, the autokey exchange is 4270 * used to retrieve the autokey values. 4271 */ 4272 else if ( sys_leap != LEAP_NOTINSYNC 4273 && peer->leap != LEAP_NOTINSYNC 4274 && !(peer->crypto & CRYPTO_FLAG_COOK)) 4275 exten = crypto_args(peer, CRYPTO_COOK, 4276 peer->associd, NULL); 4277 else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) 4278 exten = crypto_args(peer, CRYPTO_AUTO, 4279 peer->associd, NULL); 4280 else if ( peer->flags & FLAG_ASSOC 4281 && peer->crypto & CRYPTO_FLAG_SIGN) 4282 exten = crypto_args(peer, CRYPTO_AUTO | 4283 CRYPTO_RESP, peer->assoc, NULL); 4284 4285 /* 4286 * Wait for clock sync, then sign the 4287 * certificate and retrieve the leapsecond 4288 * values. 4289 */ 4290 else if (sys_leap == LEAP_NOTINSYNC) 4291 break; 4292 4293 else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) 4294 exten = crypto_args(peer, CRYPTO_SIGN, 4295 peer->associd, hostval.ptr); 4296 else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) 4297 exten = crypto_args(peer, CRYPTO_LEAP, 4298 peer->associd, NULL); 4299 break; 4300 4301 /* 4302 * In client mode the parameter, certificate, identity, 4303 * cookie and sign exchanges are required. The 4304 * leapsecond exchange is optional. If broadcast client 4305 * mode the same exchanges are required, except that the 4306 * autokey exchange is substitutes for the cookie 4307 * exchange, since the cookie is always zero. If the 4308 * broadcast client finds a broken autokey sequence, it 4309 * uses the autokey exchange to retrieve the autokey 4310 * values. 4311 */ 4312 case MODE_CLIENT: 4313 4314 /* 4315 * Parameter, certificate and identity. 4316 */ 4317 if (!peer->crypto) 4318 exten = crypto_args(peer, CRYPTO_ASSOC, 4319 peer->associd, hostval.ptr); 4320 else if (!(peer->crypto & CRYPTO_FLAG_CERT)) 4321 exten = crypto_args(peer, CRYPTO_CERT, 4322 peer->associd, peer->issuer); 4323 else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) 4324 exten = crypto_args(peer, 4325 crypto_ident(peer), peer->associd, 4326 NULL); 4327 4328 /* 4329 * Cookie and autokey. These are requests, but 4330 * we use the peer association ID with autokey 4331 * rather than our own. 4332 */ 4333 else if (!(peer->crypto & CRYPTO_FLAG_COOK)) 4334 exten = crypto_args(peer, CRYPTO_COOK, 4335 peer->associd, NULL); 4336 else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) 4337 exten = crypto_args(peer, CRYPTO_AUTO, 4338 peer->assoc, NULL); 4339 4340 /* 4341 * Wait for clock sync, then sign the 4342 * certificate and retrieve the leapsecond 4343 * values. 4344 */ 4345 else if (sys_leap == LEAP_NOTINSYNC) 4346 break; 4347 4348 else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) 4349 exten = crypto_args(peer, CRYPTO_SIGN, 4350 peer->associd, hostval.ptr); 4351 else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) 4352 exten = crypto_args(peer, CRYPTO_LEAP, 4353 peer->associd, NULL); 4354 break; 4355 } 4356 4357 /* 4358 * Add a queued extension field if present. This is 4359 * always a request message, so the reply ID is already 4360 * in the message. If an error occurs, the error bit is 4361 * lit in the response. 4362 */ 4363 if (peer->cmmd != NULL) { 4364 u_int32 temp32; 4365 4366 temp32 = CRYPTO_RESP; 4367 peer->cmmd->opcode |= htonl(temp32); 4368 sendlen += crypto_xmit(peer, &xpkt, NULL, 4369 sendlen, peer->cmmd, 0); 4370 free(peer->cmmd); 4371 peer->cmmd = NULL; 4372 } 4373 4374 /* 4375 * Add an extension field created above. All but the 4376 * autokey response message are request messages. 4377 */ 4378 if (exten != NULL) { 4379 if (exten->opcode != 0) 4380 sendlen += crypto_xmit(peer, &xpkt, 4381 NULL, sendlen, exten, 0); 4382 free(exten); 4383 } 4384 4385 /* 4386 * Calculate the next session key. Since extension 4387 * fields are present, the cookie value is zero. 4388 */ 4389 if (sendlen > (int)LEN_PKT_NOMAC) { 4390 session_key(&peer->dstadr->sin, &peer->srcadr, 4391 xkeyid, 0, 2); 4392 } 4393 } 4394#endif /* AUTOKEY */ 4395 4396 /* 4397 * Transmit a-priori timestamps 4398 */ 4399 get_systime(&xmt_tx); 4400 if (peer->flip == 0) { /* basic mode */ 4401 peer->aorg = xmt_tx; 4402 HTONL_FP(&xmt_tx, &xpkt.xmt); 4403 } else { /* interleaved modes */ 4404 if (peer->hmode == MODE_BROADCAST) { /* bcst */ 4405 HTONL_FP(&xmt_tx, &xpkt.xmt); 4406 if (peer->flip > 0) 4407 HTONL_FP(&peer->borg, &xpkt.org); 4408 else 4409 HTONL_FP(&peer->aorg, &xpkt.org); 4410 } else { /* symmetric */ 4411 if (peer->flip > 0) 4412 HTONL_FP(&peer->borg, &xpkt.xmt); 4413 else 4414 HTONL_FP(&peer->aorg, &xpkt.xmt); 4415 } 4416 } 4417 xkeyid = peer->keyid; 4418 authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); 4419 if (authlen == 0) { 4420 report_event(PEVNT_AUTH, peer, "no key"); 4421 peer->flash |= TEST5; /* auth error */ 4422 peer->badauth++; 4423 return; 4424 } 4425 sendlen += authlen; 4426#ifdef AUTOKEY 4427 if (xkeyid > NTP_MAXKEY) 4428 authtrust(xkeyid, 0); 4429#endif /* AUTOKEY */ 4430 if (sendlen > sizeof(xpkt)) { 4431 msyslog(LOG_ERR, "peer_xmit: buffer overflow %zu", sendlen); 4432 exit (-1); 4433 } 4434 peer->t21_bytes = sendlen; 4435 sendpkt(&peer->srcadr, peer->dstadr, 4436 sys_ttl[(peer->ttl >= sys_ttlmax) ? sys_ttlmax : peer->ttl], 4437 &xpkt, sendlen); 4438 peer->sent++; 4439 peer->throttle += (1 << peer->minpoll) - 2; 4440 4441 /* 4442 * Capture a-posteriori timestamps 4443 */ 4444 get_systime(&xmt_ty); 4445 if (peer->flip != 0) { /* interleaved modes */ 4446 if (peer->flip > 0) 4447 peer->aorg = xmt_ty; 4448 else 4449 peer->borg = xmt_ty; 4450 peer->flip = -peer->flip; 4451 } 4452 L_SUB(&xmt_ty, &xmt_tx); 4453 LFPTOD(&xmt_ty, peer->xleave); 4454#ifdef AUTOKEY 4455 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu index %d\n", 4456 current_time, latoa(peer->dstadr), 4457 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen, 4458 peer->keynumber)); 4459#else /* !AUTOKEY follows */ 4460 DPRINTF(1, ("peer_xmit: at %ld %s->%s mode %d keyid %08x len %zu\n", 4461 current_time, peer->dstadr ? 4462 ntoa(&peer->dstadr->sin) : "-", 4463 ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen)); 4464#endif /* !AUTOKEY */ 4465 4466 return; 4467} 4468 4469 4470#ifdef LEAP_SMEAR 4471 4472static void 4473leap_smear_add_offs( 4474 l_fp *t, 4475 l_fp *t_recv 4476 ) 4477{ 4478 4479 L_ADD(t, &leap_smear.offset); 4480 4481 /* 4482 ** XXX: Should the smear be added to the root dispersion? 4483 */ 4484 4485 return; 4486} 4487 4488#endif /* LEAP_SMEAR */ 4489 4490 4491/* 4492 * fast_xmit - Send packet for nonpersistent association. Note that 4493 * neither the source or destination can be a broadcast address. 4494 */ 4495static void 4496fast_xmit( 4497 struct recvbuf *rbufp, /* receive packet pointer */ 4498 int xmode, /* receive mode */ /* XXX: HMS: really? */ 4499 keyid_t xkeyid, /* transmit key ID */ 4500 int flags /* restrict mask */ 4501 ) 4502{ 4503 struct pkt xpkt; /* transmit packet structure */ 4504 struct pkt *rpkt; /* receive packet structure */ 4505 l_fp xmt_tx, xmt_ty; 4506 size_t sendlen; 4507#ifdef AUTOKEY 4508 u_int32 temp32; 4509#endif 4510 4511 /* 4512 * Initialize transmit packet header fields from the receive 4513 * buffer provided. We leave the fields intact as received, but 4514 * set the peer poll at the maximum of the receive peer poll and 4515 * the system minimum poll (ntp_minpoll). This is for KoD rate 4516 * control and not strictly specification compliant, but doesn't 4517 * break anything. 4518 * 4519 * If the gazinta was from a multicast address, the gazoutta 4520 * must go out another way. 4521 */ 4522 rpkt = &rbufp->recv_pkt; 4523 if (rbufp->dstadr->flags & INT_MCASTOPEN) 4524 rbufp->dstadr = findinterface(&rbufp->recv_srcadr); 4525 4526 /* 4527 * If this is a kiss-o'-death (KoD) packet, show leap 4528 * unsynchronized, stratum zero, reference ID the four-character 4529 * kiss code and (???) system root delay. Note we don't reveal 4530 * the local time, so these packets can't be used for 4531 * synchronization. 4532 */ 4533 if (flags & RES_KOD) { 4534 sys_kodsent++; 4535 xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC, 4536 PKT_VERSION(rpkt->li_vn_mode), xmode); 4537 xpkt.stratum = STRATUM_PKT_UNSPEC; 4538 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); 4539 xpkt.precision = rpkt->precision; 4540 memcpy(&xpkt.refid, "RATE", 4); 4541 xpkt.rootdelay = rpkt->rootdelay; 4542 xpkt.rootdisp = rpkt->rootdisp; 4543 xpkt.reftime = rpkt->reftime; 4544 xpkt.org = rpkt->xmt; 4545 xpkt.rec = rpkt->xmt; 4546 xpkt.xmt = rpkt->xmt; 4547 4548 /* 4549 * This is a normal packet. Use the system variables. 4550 */ 4551 } else { 4552 double this_rootdisp; 4553 l_fp this_ref_time; 4554 4555#ifdef LEAP_SMEAR 4556 /* 4557 * Make copies of the variables which can be affected by smearing. 4558 */ 4559 l_fp this_recv_time; 4560#endif 4561 4562 /* 4563 * If we are inside the leap smear interval we add 4564 * the current smear offset to: 4565 * - the packet receive time, 4566 * - the packet transmit time, 4567 * - and eventually to the reftime to make sure the 4568 * reftime isn't later than the transmit/receive times. 4569 */ 4570 xpkt.li_vn_mode = PKT_LI_VN_MODE(xmt_leap, 4571 PKT_VERSION(rpkt->li_vn_mode), xmode); 4572 4573 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 4574 xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); 4575 xpkt.precision = sys_precision; 4576 xpkt.refid = sys_refid; 4577 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 4578 4579 /* 4580 ** Server Response Fuzzing 4581 ** 4582 ** Which values do we want to use for reftime and rootdisp? 4583 */ 4584 4585 if ( MODE_SERVER == xmode 4586 && RES_SRVRSPFUZ & flags) { 4587 if (current_time < p2_time) { 4588 this_ref_time = p2_reftime; 4589 this_rootdisp = p2_rootdisp; 4590 } else if (current_time < prev_time) { 4591 this_ref_time = prev_reftime; 4592 this_rootdisp = prev_rootdisp; 4593 } else { 4594 this_ref_time = sys_reftime; 4595 this_rootdisp = sys_rootdisp; 4596 } 4597 4598 SRVRSP_FUZZ(this_ref_time); 4599 } else { 4600 this_ref_time = sys_reftime; 4601 this_rootdisp = sys_rootdisp; 4602 } 4603 4604 /* 4605 ** ROOT DISPERSION 4606 */ 4607 4608 xpkt.rootdisp = HTONS_FP(DTOUFP(this_rootdisp)); 4609 4610 /* 4611 ** REFTIME 4612 */ 4613 4614#ifdef LEAP_SMEAR 4615 if (leap_smear.in_progress) { 4616 /* adjust the reftime by the same amount as the 4617 * leap smear, as we don't want to risk the 4618 * reftime being later than the transmit time. 4619 */ 4620 leap_smear_add_offs(&this_ref_time, NULL); 4621 } 4622#endif 4623 4624 HTONL_FP(&this_ref_time, &xpkt.reftime); 4625 4626 /* 4627 ** REFID 4628 */ 4629 4630#ifdef LEAP_SMEAR 4631 if (leap_smear.in_progress) { 4632 xpkt.refid = convertLFPToRefID(leap_smear.offset); 4633 DPRINTF(2, ("fast_xmit: leap_smear.in_progress: refid %8x, smear %s\n", 4634 ntohl(xpkt.refid), 4635 lfptoa(&leap_smear.offset, 8) 4636 )); 4637 } 4638#endif 4639 4640 /* 4641 ** ORIGIN 4642 */ 4643 4644 xpkt.org = rpkt->xmt; 4645 4646 /* 4647 ** RECEIVE 4648 */ 4649#ifdef LEAP_SMEAR 4650 this_recv_time = rbufp->recv_time; 4651 if (leap_smear.in_progress) 4652 leap_smear_add_offs(&this_recv_time, NULL); 4653 HTONL_FP(&this_recv_time, &xpkt.rec); 4654#else 4655 HTONL_FP(&rbufp->recv_time, &xpkt.rec); 4656#endif 4657 4658 /* 4659 ** TRANSMIT 4660 */ 4661 4662 get_systime(&xmt_tx); 4663#ifdef LEAP_SMEAR 4664 if (leap_smear.in_progress) 4665 leap_smear_add_offs(&xmt_tx, &this_recv_time); 4666#endif 4667 HTONL_FP(&xmt_tx, &xpkt.xmt); 4668 } 4669 4670#ifdef HAVE_NTP_SIGND 4671 if (flags & RES_MSSNTP) { 4672 send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt); 4673 return; 4674 } 4675#endif /* HAVE_NTP_SIGND */ 4676 4677 /* 4678 * If the received packet contains a MAC, the transmitted packet 4679 * is authenticated and contains a MAC. If not, the transmitted 4680 * packet is not authenticated. 4681 */ 4682 sendlen = LEN_PKT_NOMAC; 4683 if (rbufp->recv_length == sendlen) { 4684 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, 4685 sendlen); 4686 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d len %lu\n", 4687 current_time, stoa(&rbufp->dstadr->sin), 4688 stoa(&rbufp->recv_srcadr), xmode, 4689 (u_long)sendlen)); 4690 return; 4691 } 4692 4693 /* 4694 * The received packet contains a MAC, so the transmitted packet 4695 * must be authenticated. For symmetric key cryptography, use 4696 * the predefined and trusted symmetric keys to generate the 4697 * cryptosum. For autokey cryptography, use the server private 4698 * value to generate the cookie, which is unique for every 4699 * source-destination-key ID combination. 4700 */ 4701#ifdef AUTOKEY 4702 if (xkeyid > NTP_MAXKEY) { 4703 keyid_t cookie; 4704 4705 /* 4706 * The only way to get here is a reply to a legitimate 4707 * client request message, so the mode must be 4708 * MODE_SERVER. If an extension field is present, there 4709 * can be only one and that must be a command. Do what 4710 * needs, but with private value of zero so the poor 4711 * jerk can decode it. If no extension field is present, 4712 * use the cookie to generate the session key. 4713 */ 4714 cookie = session_key(&rbufp->recv_srcadr, 4715 &rbufp->dstadr->sin, 0, sys_private, 0); 4716 if ((size_t)rbufp->recv_length > sendlen + MAX_MAC_LEN) { 4717 session_key(&rbufp->dstadr->sin, 4718 &rbufp->recv_srcadr, xkeyid, 0, 2); 4719 temp32 = CRYPTO_RESP; 4720 rpkt->exten[0] |= htonl(temp32); 4721 sendlen += crypto_xmit(NULL, &xpkt, rbufp, 4722 sendlen, (struct exten *)rpkt->exten, 4723 cookie); 4724 } else { 4725 session_key(&rbufp->dstadr->sin, 4726 &rbufp->recv_srcadr, xkeyid, cookie, 2); 4727 } 4728 } 4729#endif /* AUTOKEY */ 4730 get_systime(&xmt_tx); 4731 sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); 4732#ifdef AUTOKEY 4733 if (xkeyid > NTP_MAXKEY) 4734 authtrust(xkeyid, 0); 4735#endif /* AUTOKEY */ 4736 sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen); 4737 get_systime(&xmt_ty); 4738 L_SUB(&xmt_ty, &xmt_tx); 4739 sys_authdelay = xmt_ty; 4740 DPRINTF(1, ("fast_xmit: at %ld %s->%s mode %d keyid %08x len %lu\n", 4741 current_time, ntoa(&rbufp->dstadr->sin), 4742 ntoa(&rbufp->recv_srcadr), xmode, xkeyid, 4743 (u_long)sendlen)); 4744} 4745 4746 4747/* 4748 * pool_xmit - resolve hostname or send unicast solicitation for pool. 4749 */ 4750static void 4751pool_xmit( 4752 struct peer *pool /* pool solicitor association */ 4753 ) 4754{ 4755#ifdef WORKER 4756 struct pkt xpkt; /* transmit packet structure */ 4757 struct addrinfo hints; 4758 int rc; 4759 struct interface * lcladr; 4760 sockaddr_u * rmtadr; 4761 r4addr r4a; 4762 u_short restrict_mask; 4763 struct peer * p; 4764 l_fp xmt_tx; 4765 4766 DEBUG_REQUIRE(pool); 4767 if (NULL == pool->ai) { 4768 if (pool->addrs != NULL) { 4769 /* free() is used with copy_addrinfo_list() */ 4770 free(pool->addrs); 4771 pool->addrs = NULL; 4772 } 4773 ZERO(hints); 4774 hints.ai_family = AF(&pool->srcadr); 4775 hints.ai_socktype = SOCK_DGRAM; 4776 hints.ai_protocol = IPPROTO_UDP; 4777 /* ignore getaddrinfo_sometime() errors, we will retry */ 4778 rc = getaddrinfo_sometime( 4779 pool->hostname, 4780 "ntp", 4781 &hints, 4782 0, /* no retry */ 4783 &pool_name_resolved, 4784 (void *)(intptr_t)pool->associd); 4785 if (!rc) 4786 DPRINTF(1, ("pool DNS lookup %s started\n", 4787 pool->hostname)); 4788 else 4789 msyslog(LOG_ERR, 4790 "unable to start pool DNS %s: %m", 4791 pool->hostname); 4792 return; 4793 } 4794 4795 do { 4796 /* copy_addrinfo_list ai_addr points to a sockaddr_u */ 4797 rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr; 4798 pool->ai = pool->ai->ai_next; 4799 p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0, NULL); 4800 } while (p != NULL && pool->ai != NULL); 4801 if (p != NULL) 4802 return; /* out of addresses, re-query DNS next poll */ 4803 restrictions(rmtadr, &r4a); 4804 restrict_mask = r4a.rflags; 4805 if (RES_FLAGS & restrict_mask) 4806 restrict_source(rmtadr, 0, 4807 current_time + POOL_SOLICIT_WINDOW + 1); 4808 lcladr = findinterface(rmtadr); 4809 memset(&xpkt, 0, sizeof(xpkt)); 4810 xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version, 4811 MODE_CLIENT); 4812 xpkt.stratum = STRATUM_TO_PKT(sys_stratum); 4813 xpkt.ppoll = pool->hpoll; 4814 xpkt.precision = sys_precision; 4815 xpkt.refid = sys_refid; 4816 xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); 4817 xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); 4818 /* Bug 3596: What are the pros/cons of using sys_reftime here? */ 4819 HTONL_FP(&sys_reftime, &xpkt.reftime); 4820 4821 /* HMS: the following is better done after the ntp_random() calls */ 4822 get_systime(&xmt_tx); 4823 pool->aorg = xmt_tx; 4824 4825 if (FLAG_LOOPNONCE & pool->flags) { 4826 l_fp nonce; 4827 4828 do { 4829 nonce.l_ui = ntp_random(); 4830 } while (0 == nonce.l_ui); 4831 do { 4832 nonce.l_uf = ntp_random(); 4833 } while (0 == nonce.l_uf); 4834 pool->nonce = nonce; 4835 HTONL_FP(&nonce, &xpkt.xmt); 4836 } else { 4837 L_CLR(&pool->nonce); 4838 HTONL_FP(&xmt_tx, &xpkt.xmt); 4839 } 4840 sendpkt(rmtadr, lcladr, 4841 sys_ttl[(pool->ttl >= sys_ttlmax) ? sys_ttlmax : pool->ttl], 4842 &xpkt, LEN_PKT_NOMAC); 4843 pool->sent++; 4844 pool->throttle += (1 << pool->minpoll) - 2; 4845 DPRINTF(1, ("pool_xmit: at %ld %s->%s pool\n", 4846 current_time, latoa(lcladr), stoa(rmtadr))); 4847 msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr)); 4848#endif /* WORKER */ 4849} 4850 4851 4852#ifdef AUTOKEY 4853 /* 4854 * group_test - test if this is the same group 4855 * 4856 * host assoc return action 4857 * none none 0 mobilize * 4858 * none group 0 mobilize * 4859 * group none 0 mobilize * 4860 * group group 1 mobilize 4861 * group different 1 ignore 4862 * * ignore if notrust 4863 */ 4864int 4865group_test( 4866 char *grp, 4867 char *ident 4868 ) 4869{ 4870 if (grp == NULL) 4871 return (0); 4872 4873 if (strcmp(grp, sys_groupname) == 0) 4874 return (0); 4875 4876 if (ident == NULL) 4877 return (1); 4878 4879 if (strcmp(grp, ident) == 0) 4880 return (0); 4881 4882 return (1); 4883} 4884#endif /* AUTOKEY */ 4885 4886 4887#ifdef WORKER 4888void 4889pool_name_resolved( 4890 int rescode, 4891 int gai_errno, 4892 void * context, 4893 const char * name, 4894 const char * service, 4895 const struct addrinfo * hints, 4896 const struct addrinfo * res 4897 ) 4898{ 4899 struct peer * pool; /* pool solicitor association */ 4900 associd_t assoc; 4901 4902 if (rescode) { 4903 msyslog(LOG_ERR, 4904 "error resolving pool %s: %s (%d)", 4905 name, gai_strerror(rescode), rescode); 4906 return; 4907 } 4908 4909 assoc = (associd_t)(intptr_t)context; 4910 pool = findpeerbyassoc(assoc); 4911 if (NULL == pool) { 4912 msyslog(LOG_ERR, 4913 "Could not find assoc %u for pool DNS %s", 4914 assoc, name); 4915 return; 4916 } 4917 DPRINTF(1, ("pool DNS %s completed\n", name)); 4918 pool->addrs = copy_addrinfo_list(res); 4919 pool->ai = pool->addrs; 4920 pool_xmit(pool); 4921 4922} 4923#endif /* WORKER */ 4924 4925 4926#ifdef AUTOKEY 4927/* 4928 * key_expire - purge the key list 4929 */ 4930void 4931key_expire( 4932 struct peer *peer /* peer structure pointer */ 4933 ) 4934{ 4935 int i; 4936 4937 if (peer->keylist != NULL) { 4938 for (i = 0; i <= peer->keynumber; i++) 4939 authtrust(peer->keylist[i], 0); 4940 free(peer->keylist); 4941 peer->keylist = NULL; 4942 } 4943 value_free(&peer->sndval); 4944 peer->keynumber = 0; 4945 peer->flags &= ~FLAG_ASSOC; 4946 DPRINTF(1, ("key_expire: at %lu associd %d\n", current_time, 4947 peer->associd)); 4948} 4949#endif /* AUTOKEY */ 4950 4951 4952/* 4953 * local_refid(peer) - check peer refid to avoid selecting peers 4954 * currently synced to this ntpd. 4955 */ 4956static int 4957local_refid( 4958 struct peer * p 4959 ) 4960{ 4961 endpt * unicast_ep; 4962 4963 if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags)) 4964 unicast_ep = p->dstadr; 4965 else 4966 unicast_ep = findinterface(&p->srcadr); 4967 4968 if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid) 4969 return TRUE; 4970 else 4971 return FALSE; 4972} 4973 4974 4975/* 4976 * Determine if the peer is unfit for synchronization 4977 * 4978 * A peer is unfit for synchronization if 4979 * > TEST10 bad leap or stratum below floor or at or above ceiling 4980 * > TEST11 root distance exceeded for remote peer 4981 * > TEST12 a direct or indirect synchronization loop would form 4982 * > TEST13 unreachable or noselect 4983 */ 4984int /* FALSE if fit, TRUE if unfit */ 4985peer_unfit( 4986 struct peer *peer /* peer structure pointer */ 4987 ) 4988{ 4989 int rval = 0; 4990 4991 /* 4992 * A stratum error occurs if (1) the server has never been 4993 * synchronized, (2) the server stratum is below the floor or 4994 * greater than or equal to the ceiling. 4995 */ 4996 if ( peer->leap == LEAP_NOTINSYNC 4997 || peer->stratum < sys_floor 4998 || peer->stratum >= sys_ceiling) { 4999 rval |= TEST10; /* bad synch or stratum */ 5000 } 5001 5002 /* 5003 * A distance error for a remote peer occurs if the root 5004 * distance is greater than or equal to the distance threshold 5005 * plus the increment due to one host poll interval. 5006 */ 5007 if ( !(peer->flags & FLAG_REFCLOCK) 5008 && root_distance(peer) >= sys_maxdist 5009 + clock_phi * ULOGTOD(peer->hpoll)) { 5010 rval |= TEST11; /* distance exceeded */ 5011 } 5012 5013 /* 5014 * A loop error occurs if the remote peer is synchronized to the 5015 * local peer or if the remote peer is synchronized to the same 5016 * server as the local peer but only if the remote peer is 5017 * neither a reference clock nor an orphan. 5018 */ 5019 if (peer->stratum > 1 && local_refid(peer)) { 5020 rval |= TEST12; /* synchronization loop */ 5021 } 5022 5023 /* 5024 * An unreachable error occurs if the server is unreachable or 5025 * the noselect bit is set. 5026 */ 5027 if (!peer->reach || (peer->flags & FLAG_NOSELECT)) { 5028 rval |= TEST13; /* unreachable */ 5029 } 5030 5031 peer->flash &= ~PEER_TEST_MASK; 5032 peer->flash |= rval; 5033 return (rval); 5034} 5035 5036 5037/* 5038 * Find the precision of this particular machine 5039 */ 5040#define MINSTEP 20e-9 /* minimum clock increment (s) */ 5041#define MAXSTEP 1 /* maximum clock increment (s) */ 5042#define MINCHANGES 12 /* minimum number of step samples */ 5043#define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */ 5044 5045/* 5046 * This routine measures the system precision defined as the minimum of 5047 * a sequence of differences between successive readings of the system 5048 * clock. However, if a difference is less than MINSTEP, the clock has 5049 * been read more than once during a clock tick and the difference is 5050 * ignored. We set MINSTEP greater than zero in case something happens 5051 * like a cache miss, and to tolerate underlying system clocks which 5052 * ensure each reading is strictly greater than prior readings while 5053 * using an underlying stepping (not interpolated) clock. 5054 * 5055 * sys_tick and sys_precision represent the time to read the clock for 5056 * systems with high-precision clocks, and the tick interval or step 5057 * size for lower-precision stepping clocks. 5058 * 5059 * This routine also measures the time to read the clock on stepping 5060 * system clocks by counting the number of readings between changes of 5061 * the underlying clock. With either type of clock, the minimum time 5062 * to read the clock is saved as sys_fuzz, and used to ensure the 5063 * get_systime() readings always increase and are fuzzed below sys_fuzz. 5064 */ 5065void 5066measure_precision(void) 5067{ 5068 /* 5069 * With sys_fuzz set to zero, get_systime() fuzzing of low bits 5070 * is effectively disabled. trunc_os_clock is FALSE to disable 5071 * get_ostime() simulation of a low-precision system clock. 5072 */ 5073 set_sys_fuzz(0.); 5074 trunc_os_clock = FALSE; 5075 measured_tick = measure_tick_fuzz(); 5076 set_sys_tick_precision(measured_tick); 5077 msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)", 5078 sys_tick * 1e6, sys_precision); 5079 if (sys_fuzz < sys_tick) { 5080 msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec", 5081 sys_fuzz * 1e6); 5082 } 5083} 5084 5085 5086/* 5087 * measure_tick_fuzz() 5088 * 5089 * measures the minimum time to read the clock (stored in sys_fuzz) 5090 * and returns the tick, the larger of the minimum increment observed 5091 * between successive clock readings and the time to read the clock. 5092 */ 5093double 5094measure_tick_fuzz(void) 5095{ 5096 l_fp minstep; /* MINSTEP as l_fp */ 5097 l_fp val; /* current seconds fraction */ 5098 l_fp last; /* last seconds fraction */ 5099 l_fp ldiff; /* val - last */ 5100 double tick; /* computed tick value */ 5101 double diff; 5102 long repeats; 5103 long max_repeats; 5104 int changes; 5105 int i; /* log2 precision */ 5106 5107 tick = MAXSTEP; 5108 max_repeats = 0; 5109 repeats = 0; 5110 changes = 0; 5111 DTOLFP(MINSTEP, &minstep); 5112 get_systime(&last); 5113 for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) { 5114 get_systime(&val); 5115 ldiff = val; 5116 L_SUB(&ldiff, &last); 5117 last = val; 5118 if (L_ISGT(&ldiff, &minstep)) { 5119 max_repeats = max(repeats, max_repeats); 5120 repeats = 0; 5121 changes++; 5122 LFPTOD(&ldiff, diff); 5123 tick = min(diff, tick); 5124 } else { 5125 repeats++; 5126 } 5127 } 5128 if (changes < MINCHANGES) { 5129 msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)"); 5130 exit(1); 5131 } 5132 5133 if (0 == max_repeats) { 5134 set_sys_fuzz(tick); 5135 } else { 5136 set_sys_fuzz(tick / max_repeats); 5137 } 5138 5139 return tick; 5140} 5141 5142 5143void 5144set_sys_tick_precision( 5145 double tick 5146 ) 5147{ 5148 int i; 5149 5150 if (tick > 1.) { 5151 msyslog(LOG_ERR, 5152 "unsupported tick %.3f > 1s ignored", tick); 5153 return; 5154 } 5155 if (tick < measured_tick) { 5156 msyslog(LOG_ERR, 5157 "proto: tick %.3f less than measured tick %.3f, ignored", 5158 tick, measured_tick); 5159 return; 5160 } else if (tick > measured_tick) { 5161 trunc_os_clock = TRUE; 5162 msyslog(LOG_NOTICE, 5163 "proto: truncating system clock to multiples of %.9f", 5164 tick); 5165 } 5166 sys_tick = tick; 5167 5168 /* 5169 * Find the nearest power of two. 5170 */ 5171 for (i = 0; tick <= 1; i--) 5172 tick *= 2; 5173 if (tick - 1 > 1 - tick / 2) 5174 i++; 5175 5176 sys_precision = (s_char)i; 5177} 5178 5179 5180/* 5181 * init_proto - initialize the protocol module's data 5182 */ 5183void 5184init_proto(void) 5185{ 5186 l_fp dummy; 5187 int i; 5188 5189 /* 5190 * Fill in the sys_* stuff. Default is don't listen to 5191 * broadcasting, require authentication. 5192 */ 5193 set_sys_leap(LEAP_NOTINSYNC); 5194 sys_stratum = STRATUM_UNSPEC; 5195 memcpy(&sys_refid, "INIT", 4); 5196 sys_peer = NULL; 5197 sys_rootdelay = 0; 5198 sys_rootdisp = 0; 5199 L_CLR(&sys_reftime); 5200 sys_jitter = 0; 5201 measure_precision(); 5202 get_systime(&dummy); 5203 sys_survivors = 0; 5204 sys_manycastserver = 0; 5205 sys_bclient = 0; 5206 sys_bdelay = BDELAY_DEFAULT; /*[Bug 3031] delay cutoff */ 5207 sys_authenticate = 1; 5208 sys_stattime = current_time; 5209 orphwait = current_time + sys_orphwait; 5210 proto_clr_stats(); 5211 for (i = 0; i < MAX_TTL; ++i) 5212 sys_ttl[i] = (u_char)((i * 256) / MAX_TTL); 5213 sys_ttlmax = (MAX_TTL - 1); 5214 hardpps_enable = 0; 5215 stats_control = 1; 5216} 5217 5218 5219/* 5220 * proto_config - configure the protocol module 5221 */ 5222void 5223proto_config( 5224 int item, 5225 u_long value, 5226 double dvalue, 5227 sockaddr_u *svalue 5228 ) 5229{ 5230 /* 5231 * Figure out what he wants to change, then do it 5232 */ 5233 DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n", 5234 item, value, dvalue)); 5235 5236 switch (item) { 5237 5238 /* 5239 * enable and disable commands - arguments are Boolean. 5240 */ 5241 case PROTO_AUTHENTICATE: /* authentication (auth) */ 5242 sys_authenticate = value; 5243 break; 5244 5245 case PROTO_BROADCLIENT: /* broadcast client (bclient) */ 5246 sys_bclient = (int)value; 5247 if (sys_bclient == 0) 5248 io_unsetbclient(); 5249 else 5250 io_setbclient(); 5251 break; 5252 5253#ifdef REFCLOCK 5254 case PROTO_CAL: /* refclock calibrate (calibrate) */ 5255 cal_enable = value; 5256 break; 5257#endif /* REFCLOCK */ 5258 5259 case PROTO_KERNEL: /* kernel discipline (kernel) */ 5260 select_loop(value); 5261 break; 5262 5263 case PROTO_MONITOR: /* monitoring (monitor) */ 5264 if (value) 5265 mon_start(MON_ON); 5266 else { 5267 mon_stop(MON_ON); 5268 if (mon_enabled) 5269 msyslog(LOG_WARNING, 5270 "restrict: 'monitor' cannot be disabled while 'limited' is enabled"); 5271 } 5272 break; 5273 5274 case PROTO_NTP: /* NTP discipline (ntp) */ 5275 ntp_enable = value; 5276 break; 5277 5278 case PROTO_MODE7: /* mode7 management (ntpdc) */ 5279 ntp_mode7 = value; 5280 break; 5281 5282 case PROTO_PPS: /* PPS discipline (pps) */ 5283 hardpps_enable = value; 5284 break; 5285 5286 case PROTO_FILEGEN: /* statistics (stats) */ 5287 stats_control = value; 5288 break; 5289 5290 /* 5291 * tos command - arguments are double, sometimes cast to int 5292 */ 5293 5294 case PROTO_BCPOLLBSTEP: /* Broadcast Poll Backstep gate (bcpollbstep) */ 5295 sys_bcpollbstep = (u_char)dvalue; 5296 break; 5297 5298 case PROTO_BEACON: /* manycast beacon (beacon) */ 5299 sys_beacon = (int)dvalue; 5300 break; 5301 5302 case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */ 5303 sys_bdelay = (dvalue ? dvalue : BDELAY_DEFAULT); 5304 break; 5305 5306 case PROTO_CEILING: /* stratum ceiling (ceiling) */ 5307 sys_ceiling = (int)dvalue; 5308 break; 5309 5310 case PROTO_COHORT: /* cohort switch (cohort) */ 5311 sys_cohort = (int)dvalue; 5312 break; 5313 5314 case PROTO_FLOOR: /* stratum floor (floor) */ 5315 sys_floor = (int)dvalue; 5316 break; 5317 5318 case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */ 5319 sys_maxclock = (int)dvalue; 5320 break; 5321 5322 case PROTO_MAXDIST: /* select threshold (maxdist) */ 5323 sys_maxdist = dvalue; 5324 break; 5325 5326 case PROTO_CALLDELAY: /* modem call delay (mdelay) */ 5327 break; /* NOT USED */ 5328 5329 case PROTO_MINCLOCK: /* minimum candidates (minclock) */ 5330 sys_minclock = (int)dvalue; 5331 break; 5332 5333 case PROTO_MINDISP: /* minimum distance (mindist) */ 5334 sys_mindisp = dvalue; 5335 break; 5336 5337 case PROTO_MINSANE: /* minimum survivors (minsane) */ 5338 sys_minsane = (int)dvalue; 5339 break; 5340 5341 case PROTO_ORPHAN: /* orphan stratum (orphan) */ 5342 sys_orphan = (int)dvalue; 5343 break; 5344 5345 case PROTO_ORPHWAIT: /* orphan wait (orphwait) */ 5346 orphwait -= sys_orphwait; 5347 sys_orphwait = (int)dvalue; 5348 orphwait += sys_orphwait; 5349 break; 5350 5351 /* 5352 * Miscellaneous commands 5353 */ 5354 case PROTO_MULTICAST_ADD: /* add group address */ 5355 if (svalue != NULL) 5356 io_multicast_add(svalue); 5357 sys_bclient = 1; 5358 break; 5359 5360 case PROTO_MULTICAST_DEL: /* delete group address */ 5361 if (svalue != NULL) 5362 io_multicast_del(svalue); 5363 break; 5364 5365 /* 5366 * Peer_clear Early policy choices 5367 */ 5368 5369 case PROTO_PCEDIGEST: /* Digest */ 5370 peer_clear_digest_early = value; 5371 break; 5372 5373 /* 5374 * Unpeer Early policy choices 5375 */ 5376 5377 case PROTO_UECRYPTO: /* Crypto */ 5378 unpeer_crypto_early = value; 5379 break; 5380 5381 case PROTO_UECRYPTONAK: /* Crypto_NAK */ 5382 unpeer_crypto_nak_early = value; 5383 break; 5384 5385 case PROTO_UEDIGEST: /* Digest */ 5386 unpeer_digest_early = value; 5387 break; 5388 5389 default: 5390 msyslog(LOG_NOTICE, 5391 "proto: unsupported option %d", item); 5392 } 5393} 5394 5395 5396/* 5397 * proto_clr_stats - clear protocol stat counters 5398 */ 5399void 5400proto_clr_stats(void) 5401{ 5402 sys_stattime = current_time; 5403 sys_received = 0; 5404 sys_processed = 0; 5405 sys_newversion = 0; 5406 sys_oldversion = 0; 5407 sys_declined = 0; 5408 sys_restricted = 0; 5409 sys_badlength = 0; 5410 sys_badauth = 0; 5411 sys_limitrejected = 0; 5412 sys_kodsent = 0; 5413 sys_lamport = 0; 5414 sys_tsrounding = 0; 5415} 5416