diff options
Diffstat (limited to 'ntpd/ntp_proto.c')
| -rw-r--r-- | ntpd/ntp_proto.c | 4168 |
1 files changed, 4168 insertions, 0 deletions
diff --git a/ntpd/ntp_proto.c b/ntpd/ntp_proto.c new file mode 100644 index 0000000..2f7543f --- /dev/null +++ b/ntpd/ntp_proto.c @@ -0,0 +1,4168 @@ +/* + * ntp_proto.c - NTP version 4 protocol machinery + * + * ATTENTION: Get approval from Dave Mills on all changes to this file! + * + */ +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "ntpd.h" +#include "ntp_stdlib.h" +#include "ntp_unixtime.h" +#include "ntp_control.h" +#include "ntp_string.h" +#include "ntp_leapsec.h" + +#include <stdio.h> +#ifdef HAVE_LIBSCF_H +#include <libscf.h> +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif + +/* + * This macro defines the authentication state. If x is 1 authentication + * is required; othewise it is optional. + */ +#define AUTH(x, y) ((x) ? (y) == AUTH_OK : (y) == AUTH_OK || \ + (y) == AUTH_NONE) + +#define AUTH_NONE 0 /* authentication not required */ +#define AUTH_OK 1 /* authentication OK */ +#define AUTH_ERROR 2 /* authentication error */ +#define AUTH_CRYPTO 3 /* crypto_NAK */ + +/* + * traffic shaping parameters + */ +#define NTP_IBURST 6 /* packets in iburst */ +#define RESP_DELAY 1 /* refclock burst delay (s) */ + +/* + * pool soliciting restriction duration (s) + */ +#define POOL_SOLICIT_WINDOW 8 + +/* + * peer_select groups statistics for a peer used by clock_select() and + * clock_cluster(). + */ +typedef struct peer_select_tag { + struct peer * peer; + double synch; /* sync distance */ + double error; /* jitter */ + double seljit; /* selection jitter */ +} peer_select; + +/* + * System variables are declared here. Unless specified otherwise, all + * times are in seconds. + */ +u_char sys_leap; /* system leap indicator */ +u_char sys_stratum; /* system stratum */ +s_char sys_precision; /* local clock precision (log2 s) */ +double sys_rootdelay; /* roundtrip delay to primary source */ +double sys_rootdisp; /* dispersion to primary source */ +u_int32 sys_refid; /* reference id (network byte order) */ +l_fp sys_reftime; /* last update time */ +struct peer *sys_peer; /* current peer */ + +/* + * Rate controls. Leaky buckets are used to throttle the packet + * transmission rates in order to protect busy servers such as at NIST + * and USNO. There is a counter for each association and another for KoD + * packets. The association counter decrements each second, but not + * below zero. Each time a packet is sent the counter is incremented by + * a configurable value representing the average interval between + * packets. A packet is delayed as long as the counter is greater than + * zero. Note this does not affect the time value computations. + */ +/* + * Nonspecified system state variables + */ +int sys_bclient; /* broadcast client enable */ +double sys_bdelay; /* broadcast client default delay */ +int sys_authenticate; /* requre authentication for config */ +l_fp sys_authdelay; /* authentication delay */ +double sys_offset; /* current local clock offset */ +double sys_mindisp = MINDISPERSE; /* minimum distance (s) */ +double sys_maxdist = MAXDISTANCE; /* selection threshold */ +double sys_jitter; /* system jitter */ +u_long sys_epoch; /* last clock update time */ +static double sys_clockhop; /* clockhop threshold */ +static int leap_vote_ins; /* leap consensus for insert */ +static int leap_vote_del; /* leap consensus for delete */ +keyid_t sys_private; /* private value for session seed */ +int sys_manycastserver; /* respond to manycast client pkts */ +int ntp_mode7; /* respond to ntpdc (mode7) */ +int peer_ntpdate; /* active peers in ntpdate mode */ +int sys_survivors; /* truest of the truechimers */ +char *sys_ident = NULL; /* identity scheme */ + +/* + * TOS and multicast mapping stuff + */ +int sys_floor = 0; /* cluster stratum floor */ +int sys_ceiling = STRATUM_UNSPEC - 1; /* cluster stratum ceiling */ +int sys_minsane = 1; /* minimum candidates */ +int sys_minclock = NTP_MINCLOCK; /* minimum candidates */ +int sys_maxclock = NTP_MAXCLOCK; /* maximum candidates */ +int sys_cohort = 0; /* cohort switch */ +int sys_orphan = STRATUM_UNSPEC + 1; /* orphan stratum */ +int sys_orphwait = NTP_ORPHWAIT; /* orphan wait */ +int sys_beacon = BEACON; /* manycast beacon interval */ +int sys_ttlmax; /* max ttl mapping vector index */ +u_char sys_ttl[MAX_TTL]; /* ttl mapping vector */ + +/* + * Statistics counters - first the good, then the bad + */ +u_long sys_stattime; /* elapsed time */ +u_long sys_received; /* packets received */ +u_long sys_processed; /* packets for this host */ +u_long sys_newversion; /* current version */ +u_long sys_oldversion; /* old version */ +u_long sys_restricted; /* access denied */ +u_long sys_badlength; /* bad length or format */ +u_long sys_badauth; /* bad authentication */ +u_long sys_declined; /* declined */ +u_long sys_limitrejected; /* rate exceeded */ +u_long sys_kodsent; /* KoD sent */ + +static double root_distance (struct peer *); +static void clock_combine (peer_select *, int, int); +static void peer_xmit (struct peer *); +static void fast_xmit (struct recvbuf *, int, keyid_t, int); +static void pool_xmit (struct peer *); +static void clock_update (struct peer *); +static void measure_precision(void); +static double measure_tick_fuzz(void); +static int local_refid (struct peer *); +static int peer_unfit (struct peer *); +#ifdef AUTOKEY +static int group_test (char *, char *); +#endif /* AUTOKEY */ +#ifdef WORKER +void pool_name_resolved (int, int, void *, const char *, + const char *, const struct addrinfo *, + const struct addrinfo *); +#endif /* WORKER */ + + +/* + * transmit - transmit procedure called by poll timeout + */ +void +transmit( + struct peer *peer /* peer structure pointer */ + ) +{ + u_char hpoll; + + /* + * The polling state machine. There are two kinds of machines, + * those that never expect a reply (broadcast and manycast + * server modes) and those that do (all other modes). The dance + * is intricate... + */ + hpoll = peer->hpoll; + + /* + * In broadcast mode the poll interval is never changed from + * minpoll. + */ + if (peer->cast_flags & (MDF_BCAST | MDF_MCAST)) { + peer->outdate = current_time; + if (sys_leap != LEAP_NOTINSYNC) + peer_xmit(peer); + poll_update(peer, hpoll); + return; + } + + /* + * In manycast mode we start with unity ttl. The ttl is + * increased by one for each poll until either sys_maxclock + * servers have been found or the maximum ttl is reached. When + * sys_maxclock servers are found we stop polling until one or + * more servers have timed out or until less than sys_minclock + * associations turn up. In this case additional better servers + * are dragged in and preempt the existing ones. Once every + * sys_beacon seconds we are to transmit unconditionally, but + * this code is not quite right -- peer->unreach counts polls + * and is being compared with sys_beacon, so the beacons happen + * every sys_beacon polls. + */ + if (peer->cast_flags & MDF_ACAST) { + peer->outdate = current_time; + if (peer->unreach > sys_beacon) { + peer->unreach = 0; + peer->ttl = 0; + peer_xmit(peer); + } else if (sys_survivors < sys_minclock || + peer_associations < sys_maxclock) { + if (peer->ttl < (u_int32)sys_ttlmax) + peer->ttl++; + peer_xmit(peer); + } + peer->unreach++; + poll_update(peer, hpoll); + return; + } + + /* + * Pool associations transmit unicast solicitations when there + * are less than a hard limit of 2 * sys_maxclock associations, + * and either less than sys_minclock survivors or less than + * sys_maxclock associations. The hard limit prevents unbounded + * growth in associations if the system clock or network quality + * result in survivor count dipping below sys_minclock often. + * This was observed testing with pool, where sys_maxclock == 12 + * resulted in 60 associations without the hard limit. A + * similar hard limit on manycastclient ephemeral associations + * may be appropriate. + */ + if (peer->cast_flags & MDF_POOL) { + peer->outdate = current_time; + if ((peer_associations <= 2 * sys_maxclock) && + (peer_associations < sys_maxclock || + sys_survivors < sys_minclock)) + pool_xmit(peer); + poll_update(peer, hpoll); + return; + } + + /* + * In unicast modes the dance is much more intricate. It is + * designed to back off whenever possible to minimize network + * traffic. + */ + if (peer->burst == 0) { + u_char oreach; + + /* + * Update the reachability status. If not heard for + * three consecutive polls, stuff infinity in the clock + * filter. + */ + oreach = peer->reach; + peer->outdate = current_time; + peer->unreach++; + peer->reach <<= 1; + if (!peer->reach) { + + /* + * Here the peer is unreachable. If it was + * previously reachable raise a trap. Send a + * burst if enabled. + */ + clock_filter(peer, 0., 0., MAXDISPERSE); + if (oreach) { + peer_unfit(peer); + report_event(PEVNT_UNREACH, peer, NULL); + } + if ((peer->flags & FLAG_IBURST) && + peer->retry == 0) + peer->retry = NTP_RETRY; + } else { + + /* + * Here the peer is reachable. Send a burst if + * enabled and the peer is fit. Reset unreach + * for persistent and ephemeral associations. + * Unreach is also reset for survivors in + * clock_select(). + */ + hpoll = sys_poll; + if (!(peer->flags & FLAG_PREEMPT)) + peer->unreach = 0; + if ((peer->flags & FLAG_BURST) && peer->retry == + 0 && !peer_unfit(peer)) + peer->retry = NTP_RETRY; + } + + /* + * Watch for timeout. If ephemeral, toss the rascal; + * otherwise, bump the poll interval. Note the + * poll_update() routine will clamp it to maxpoll. + * If preemptible and we have more peers than maxclock, + * and this peer has the minimum score of preemptibles, + * demobilize. + */ + if (peer->unreach >= NTP_UNREACH) { + hpoll++; + /* ephemeral: no FLAG_CONFIG nor FLAG_PREEMPT */ + if (!(peer->flags & (FLAG_CONFIG | FLAG_PREEMPT))) { + report_event(PEVNT_RESTART, peer, "timeout"); + peer_clear(peer, "TIME"); + unpeer(peer); + return; + } + if ((peer->flags & FLAG_PREEMPT) && + (peer_associations > sys_maxclock) && + score_all(peer)) { + report_event(PEVNT_RESTART, peer, "timeout"); + peer_clear(peer, "TIME"); + unpeer(peer); + return; + } + } + } else { + peer->burst--; + if (peer->burst == 0) { + + /* + * If ntpdate mode and the clock has not been + * set and all peers have completed the burst, + * we declare a successful failure. + */ + if (mode_ntpdate) { + peer_ntpdate--; + if (peer_ntpdate == 0) { + msyslog(LOG_NOTICE, + "ntpd: no servers found"); + if (!msyslog_term) + printf( + "ntpd: no servers found\n"); + exit (0); + } + } + } + } + if (peer->retry > 0) + peer->retry--; + + /* + * Do not transmit if in broadcast client mode. + */ + if (peer->hmode != MODE_BCLIENT) + peer_xmit(peer); + poll_update(peer, hpoll); +} + + +/* + * receive - receive procedure called for each packet received + */ +void +receive( + struct recvbuf *rbufp + ) +{ + register struct peer *peer; /* peer structure pointer */ + register struct pkt *pkt; /* receive packet pointer */ + u_char hisversion; /* packet version */ + u_char hisleap; /* packet leap indicator */ + u_char hismode; /* packet mode */ + u_char hisstratum; /* packet stratum */ + u_short restrict_mask; /* restrict bits */ + int has_mac; /* length of MAC field */ + int authlen; /* offset of MAC field */ + int is_authentic = 0; /* cryptosum ok */ + int retcode = AM_NOMATCH; /* match code */ + keyid_t skeyid = 0; /* key IDs */ + u_int32 opcode = 0; /* extension field opcode */ + sockaddr_u *dstadr_sin; /* active runway */ + struct peer *peer2; /* aux peer structure pointer */ + endpt * match_ep; /* newpeer() local address */ + l_fp p_org; /* origin timestamp */ + l_fp p_rec; /* receive timestamp */ + l_fp p_xmt; /* transmit timestamp */ +#ifdef AUTOKEY + char hostname[NTP_MAXSTRLEN + 1]; + char *groupname = NULL; + struct autokey *ap; /* autokey structure pointer */ + int rval; /* cookie snatcher */ + keyid_t pkeyid = 0, tkeyid = 0; /* key IDs */ +#endif /* AUTOKEY */ +#ifdef HAVE_NTP_SIGND + static unsigned char zero_key[16]; +#endif /* HAVE_NTP_SIGND */ + + /* + * Monitor the packet and get restrictions. Note that the packet + * length for control and private mode packets must be checked + * by the service routines. Some restrictions have to be handled + * later in order to generate a kiss-o'-death packet. + */ + /* + * Bogus port check is before anything, since it probably + * reveals a clogging attack. + */ + sys_received++; + if (0 == SRCPORT(&rbufp->recv_srcadr)) { + sys_badlength++; + return; /* bogus port */ + } + restrict_mask = restrictions(&rbufp->recv_srcadr); + DPRINTF(2, ("receive: at %ld %s<-%s flags %x restrict %03x\n", + current_time, stoa(&rbufp->dstadr->sin), + stoa(&rbufp->recv_srcadr), + rbufp->dstadr->flags, restrict_mask)); + pkt = &rbufp->recv_pkt; + hisversion = PKT_VERSION(pkt->li_vn_mode); + hisleap = PKT_LEAP(pkt->li_vn_mode); + hismode = (int)PKT_MODE(pkt->li_vn_mode); + hisstratum = PKT_TO_STRATUM(pkt->stratum); + if (restrict_mask & RES_IGNORE) { + sys_restricted++; + return; /* ignore everything */ + } + if (hismode == MODE_PRIVATE) { + if (!ntp_mode7 || (restrict_mask & RES_NOQUERY)) { + sys_restricted++; + return; /* no query private */ + } + process_private(rbufp, ((restrict_mask & + RES_NOMODIFY) == 0)); + return; + } + if (hismode == MODE_CONTROL) { + if (restrict_mask & RES_NOQUERY) { + sys_restricted++; + return; /* no query control */ + } + process_control(rbufp, restrict_mask); + return; + } + if (restrict_mask & RES_DONTSERVE) { + sys_restricted++; + return; /* no time serve */ + } + + /* + * This is for testing. If restricted drop ten percent of + * surviving packets. + */ + if (restrict_mask & RES_FLAKE) { + if ((double)ntp_random() / 0x7fffffff < .1) { + sys_restricted++; + return; /* no flakeway */ + } + } + + /* + * Version check must be after the query packets, since they + * intentionally use an early version. + */ + if (hisversion == NTP_VERSION) { + sys_newversion++; /* new version */ + } else if (!(restrict_mask & RES_VERSION) && hisversion >= + NTP_OLDVERSION) { + sys_oldversion++; /* previous version */ + } else { + sys_badlength++; + return; /* old version */ + } + + /* + * Figure out his mode and validate the packet. This has some + * legacy raunch that probably should be removed. In very early + * NTP versions mode 0 was equivalent to what later versions + * would interpret as client mode. + */ + if (hismode == MODE_UNSPEC) { + if (hisversion == NTP_OLDVERSION) { + hismode = MODE_CLIENT; + } else { + sys_badlength++; + return; /* invalid mode */ + } + } + + /* + * Parse the extension field if present. We figure out whether + * an extension field is present by measuring the MAC size. If + * the number of words following the packet header is 0, no MAC + * is present and the packet is not authenticated. If 1, the + * packet is a crypto-NAK; if 3, the packet is authenticated + * with DES; if 5, the packet is authenticated with MD5; if 6, + * the packet is authenticated with SHA. If 2 or * 4, the packet + * is a runt and discarded forthwith. If greater than 6, an + * extension field is present, so we subtract the length of the + * field and go around again. + */ + authlen = LEN_PKT_NOMAC; + has_mac = rbufp->recv_length - authlen; + while (has_mac != 0) { + u_int32 len; +#ifdef AUTOKEY + u_int32 hostlen; + struct exten *ep; +#endif /*AUTOKEY */ + + if (has_mac % 4 != 0 || has_mac < MIN_MAC_LEN) { + sys_badlength++; + return; /* bad length */ + } + if (has_mac <= MAX_MAC_LEN) { + skeyid = ntohl(((u_int32 *)pkt)[authlen / 4]); + break; + + } else { + opcode = ntohl(((u_int32 *)pkt)[authlen / 4]); + len = opcode & 0xffff; + if (len % 4 != 0 || len < 4 || (int)len + + authlen > rbufp->recv_length) { + sys_badlength++; + return; /* bad length */ + } +#ifdef AUTOKEY + /* + * Extract calling group name for later. If + * sys_groupname is non-NULL, there must be + * a group name provided to elicit a response. + */ + if ((opcode & 0x3fff0000) == CRYPTO_ASSOC && + sys_groupname != NULL) { + ep = (struct exten *)&((u_int32 *)pkt)[authlen / 4]; + hostlen = ntohl(ep->vallen); + if (hostlen >= sizeof(hostname) || + hostlen > len - + offsetof(struct exten, pkt)) { + sys_badlength++; + return; /* bad length */ + } + memcpy(hostname, &ep->pkt, hostlen); + hostname[hostlen] = '\0'; + groupname = strchr(hostname, '@'); + if (groupname == NULL) { + sys_declined++; + return; + } + groupname++; + } +#endif /* AUTOKEY */ + authlen += len; + has_mac -= len; + } + } + + /* + * If authentication required, a MAC must be present. + */ + if (restrict_mask & RES_DONTTRUST && has_mac == 0) { + sys_restricted++; + return; /* access denied */ + } + + /* + * Update the MRU list and finger the cloggers. It can be a + * little expensive, so turn it off for production use. + * RES_LIMITED and RES_KOD will be cleared in the returned + * restrict_mask unless one or both actions are warranted. + */ + restrict_mask = ntp_monitor(rbufp, restrict_mask); + if (restrict_mask & RES_LIMITED) { + sys_limitrejected++; + if (!(restrict_mask & RES_KOD) || MODE_BROADCAST == + hismode || MODE_SERVER == hismode) { + if (MODE_SERVER == hismode) + DPRINTF(1, ("Possibly self-induced rate limiting of MODE_SERVER from %s\n", + stoa(&rbufp->recv_srcadr))); + return; /* rate exceeded */ + } + if (hismode == MODE_CLIENT) + fast_xmit(rbufp, MODE_SERVER, skeyid, + restrict_mask); + else + fast_xmit(rbufp, MODE_ACTIVE, skeyid, + restrict_mask); + return; /* rate exceeded */ + } + restrict_mask &= ~RES_KOD; + + /* + * We have tossed out as many buggy packets as possible early in + * the game to reduce the exposure to a clogging attack. Now we + * have to burn some cycles to find the association and + * authenticate the packet if required. Note that we burn only + * digest cycles, again to reduce exposure. There may be no + * matching association and that's okay. + * + * More on the autokey mambo. Normally the local interface is + * found when the association was mobilized with respect to a + * designated remote address. We assume packets arriving from + * the remote address arrive via this interface and the local + * address used to construct the autokey is the unicast address + * of the interface. However, if the sender is a broadcaster, + * the interface broadcast address is used instead. + * Notwithstanding this technobabble, if the sender is a + * multicaster, the broadcast address is null, so we use the + * unicast address anyway. Don't ask. + */ + peer = findpeer(rbufp, hismode, &retcode); + dstadr_sin = &rbufp->dstadr->sin; + NTOHL_FP(&pkt->org, &p_org); + NTOHL_FP(&pkt->rec, &p_rec); + NTOHL_FP(&pkt->xmt, &p_xmt); + + /* + * Authentication is conditioned by three switches: + * + * NOPEER (RES_NOPEER) do not mobilize an association unless + * authenticated + * NOTRUST (RES_DONTTRUST) do not allow access unless + * authenticated (implies NOPEER) + * enable (sys_authenticate) master NOPEER switch, by default + * on + * + * The NOPEER and NOTRUST can be specified on a per-client basis + * using the restrict command. The enable switch if on implies + * NOPEER for all clients. There are four outcomes: + * + * NONE The packet has no MAC. + * OK the packet has a MAC and authentication succeeds + * ERROR the packet has a MAC and authentication fails + * CRYPTO crypto-NAK. The MAC has four octets only. + * + * Note: The AUTH(x, y) macro is used to filter outcomes. If x + * is zero, acceptable outcomes of y are NONE and OK. If x is + * one, the only acceptable outcome of y is OK. + */ + + if (has_mac == 0) { + restrict_mask &= ~RES_MSSNTP; + is_authentic = AUTH_NONE; /* not required */ +#ifdef DEBUG + if (debug) + printf( + "receive: at %ld %s<-%s mode %d len %d\n", + current_time, stoa(dstadr_sin), + stoa(&rbufp->recv_srcadr), hismode, + authlen); +#endif + } else if (has_mac == 4) { + restrict_mask &= ~RES_MSSNTP; + is_authentic = AUTH_CRYPTO; /* crypto-NAK */ +#ifdef DEBUG + if (debug) + printf( + "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n", + current_time, stoa(dstadr_sin), + stoa(&rbufp->recv_srcadr), hismode, skeyid, + authlen + has_mac, is_authentic); +#endif + +#ifdef HAVE_NTP_SIGND + /* + * If the signature is 20 bytes long, the last 16 of + * which are zero, then this is a Microsoft client + * wanting AD-style authentication of the server's + * reply. + * + * This is described in Microsoft's WSPP docs, in MS-SNTP: + * http://msdn.microsoft.com/en-us/library/cc212930.aspx + */ + } else if (has_mac == MAX_MD5_LEN && (restrict_mask & RES_MSSNTP) && + (retcode == AM_FXMIT || retcode == AM_NEWPASS) && + (memcmp(zero_key, (char *)pkt + authlen + 4, MAX_MD5_LEN - 4) == + 0)) { + is_authentic = AUTH_NONE; +#endif /* HAVE_NTP_SIGND */ + + } else { + restrict_mask &= ~RES_MSSNTP; +#ifdef AUTOKEY + /* + * For autokey modes, generate the session key + * and install in the key cache. Use the socket + * broadcast or unicast address as appropriate. + */ + if (crypto_flags && skeyid > NTP_MAXKEY) { + + /* + * More on the autokey dance (AKD). A cookie is + * constructed from public and private values. + * For broadcast packets, the cookie is public + * (zero). For packets that match no + * association, the cookie is hashed from the + * addresses and private value. For server + * packets, the cookie was previously obtained + * from the server. For symmetric modes, the + * cookie was previously constructed using an + * agreement protocol; however, should PKI be + * unavailable, we construct a fake agreement as + * the EXOR of the peer and host cookies. + * + * hismode ephemeral persistent + * ======================================= + * active 0 cookie# + * passive 0% cookie# + * client sys cookie 0% + * server 0% sys cookie + * broadcast 0 0 + * + * # if unsync, 0 + * % can't happen + */ + if (has_mac < MAX_MD5_LEN) { + sys_badauth++; + return; + } + if (hismode == MODE_BROADCAST) { + + /* + * For broadcaster, use the interface + * broadcast address when available; + * otherwise, use the unicast address + * found when the association was + * mobilized. However, if this is from + * the wildcard interface, game over. + */ + if (crypto_flags && rbufp->dstadr == + ANY_INTERFACE_CHOOSE(&rbufp->recv_srcadr)) { + sys_restricted++; + return; /* no wildcard */ + } + pkeyid = 0; + if (!SOCK_UNSPEC(&rbufp->dstadr->bcast)) + dstadr_sin = + &rbufp->dstadr->bcast; + } else if (peer == NULL) { + pkeyid = session_key( + &rbufp->recv_srcadr, dstadr_sin, 0, + sys_private, 0); + } else { + pkeyid = peer->pcookie; + } + + /* + * The session key includes both the public + * values and cookie. In case of an extension + * field, the cookie used for authentication + * purposes is zero. Note the hash is saved for + * use later in the autokey mambo. + */ + if (authlen > LEN_PKT_NOMAC && pkeyid != 0) { + session_key(&rbufp->recv_srcadr, + dstadr_sin, skeyid, 0, 2); + tkeyid = session_key( + &rbufp->recv_srcadr, dstadr_sin, + skeyid, pkeyid, 0); + } else { + tkeyid = session_key( + &rbufp->recv_srcadr, dstadr_sin, + skeyid, pkeyid, 2); + } + + } +#endif /* AUTOKEY */ + + /* + * Compute the cryptosum. Note a clogging attack may + * succeed in bloating the key cache. If an autokey, + * purge it immediately, since we won't be needing it + * again. If the packet is authentic, it can mobilize an + * association. Note that there is no key zero. + */ + if (!authdecrypt(skeyid, (u_int32 *)pkt, authlen, + has_mac)) + is_authentic = AUTH_ERROR; + else + is_authentic = AUTH_OK; +#ifdef AUTOKEY + if (crypto_flags && skeyid > NTP_MAXKEY) + authtrust(skeyid, 0); +#endif /* AUTOKEY */ +#ifdef DEBUG + if (debug) + printf( + "receive: at %ld %s<-%s mode %d keyid %08x len %d auth %d\n", + current_time, stoa(dstadr_sin), + stoa(&rbufp->recv_srcadr), hismode, skeyid, + authlen + has_mac, is_authentic); +#endif + } + + /* + * The association matching rules are implemented by a set of + * routines and an association table. A packet matching an + * association is processed by the peer process for that + * association. If there are no errors, an ephemeral association + * is mobilized: a broadcast packet mobilizes a broadcast client + * aassociation; a manycast server packet mobilizes a manycast + * client association; a symmetric active packet mobilizes a + * symmetric passive association. + */ + switch (retcode) { + + /* + * This is a client mode packet not matching any association. If + * an ordinary client, simply toss a server mode packet back + * over the fence. If a manycast client, we have to work a + * little harder. + */ + case AM_FXMIT: + + /* + * If authentication OK, send a server reply; otherwise, + * send a crypto-NAK. + */ + if (!(rbufp->dstadr->flags & INT_MCASTOPEN)) { + if (AUTH(restrict_mask & RES_DONTTRUST, + is_authentic)) { + fast_xmit(rbufp, MODE_SERVER, skeyid, + restrict_mask); + } else if (is_authentic == AUTH_ERROR) { + fast_xmit(rbufp, MODE_SERVER, 0, + restrict_mask); + sys_badauth++; + } else { + sys_restricted++; + } + return; /* hooray */ + } + + /* + * This must be manycast. Do not respond if not + * configured as a manycast server. + */ + if (!sys_manycastserver) { + sys_restricted++; + return; /* not enabled */ + } + +#ifdef AUTOKEY + /* + * Do not respond if not the same group. + */ + if (group_test(groupname, NULL)) { + sys_declined++; + return; + } +#endif /* AUTOKEY */ + + /* + * Do not respond if we are not synchronized or our + * stratum is greater than the manycaster or the + * manycaster has already synchronized to us. + */ + if (sys_leap == LEAP_NOTINSYNC || sys_stratum >= + hisstratum || (!sys_cohort && sys_stratum == + hisstratum + 1) || rbufp->dstadr->addr_refid == + pkt->refid) { + sys_declined++; + return; /* no help */ + } + + /* + * Respond only if authentication succeeds. Don't do a + * crypto-NAK, as that would not be useful. + */ + if (AUTH(restrict_mask & RES_DONTTRUST, is_authentic)) + fast_xmit(rbufp, MODE_SERVER, skeyid, + restrict_mask); + return; /* hooray */ + + /* + * This is a server mode packet returned in response to a client + * mode packet sent to a multicast group address (for + * manycastclient) or to a unicast address (for pool). The + * origin timestamp is a good nonce to reliably associate the + * reply with what was sent. If there is no match, that's + * curious and could be an intruder attempting to clog, so we + * just ignore it. + * + * If the packet is authentic and the manycastclient or pool + * association is found, we mobilize a client association and + * copy pertinent variables from the manycastclient or pool + * association to the new client association. If not, just + * ignore the packet. + * + * There is an implosion hazard at the manycast client, since + * the manycast servers send the server packet immediately. If + * the guy is already here, don't fire up a duplicate. + */ + case AM_MANYCAST: + +#ifdef AUTOKEY + /* + * Do not respond if not the same group. + */ + if (group_test(groupname, NULL)) { + sys_declined++; + return; + } +#endif /* AUTOKEY */ + if ((peer2 = findmanycastpeer(rbufp)) == NULL) { + sys_restricted++; + return; /* not enabled */ + } + if (!AUTH((!(peer2->cast_flags & MDF_POOL) && + sys_authenticate) | (restrict_mask & (RES_NOPEER | + RES_DONTTRUST)), is_authentic)) { + sys_restricted++; + return; /* access denied */ + } + + /* + * Do not respond if unsynchronized or stratum is below + * the floor or at or above the ceiling. + */ + if (hisleap == LEAP_NOTINSYNC || hisstratum < + sys_floor || hisstratum >= sys_ceiling) { + sys_declined++; + return; /* no help */ + } + peer = newpeer(&rbufp->recv_srcadr, NULL, rbufp->dstadr, + MODE_CLIENT, hisversion, peer2->minpoll, + peer2->maxpoll, FLAG_PREEMPT | + (FLAG_IBURST & peer2->flags), MDF_UCAST | + MDF_UCLNT, 0, skeyid, sys_ident); + if (NULL == peer) { + sys_declined++; + return; /* ignore duplicate */ + } + + /* + * After each ephemeral pool association is spun, + * accelerate the next poll for the pool solicitor so + * the pool will fill promptly. + */ + if (peer2->cast_flags & MDF_POOL) + peer2->nextdate = current_time + 1; + + /* + * Further processing of the solicitation response would + * simply detect its origin timestamp as bogus for the + * brand-new association (it matches the prototype + * association) and tinker with peer->nextdate delaying + * first sync. + */ + return; /* solicitation response handled */ + + /* + * This is the first packet received from a broadcast server. If + * the packet is authentic and we are enabled as broadcast + * client, mobilize a broadcast client association. We don't + * kiss any frogs here. + */ + case AM_NEWBCL: + +#ifdef AUTOKEY + /* + * Do not respond if not the same group. + */ + if (group_test(groupname, sys_ident)) { + sys_declined++; + return; + } +#endif /* AUTOKEY */ + if (sys_bclient == 0) { + sys_restricted++; + return; /* not enabled */ + } + if (!AUTH(sys_authenticate | (restrict_mask & + (RES_NOPEER | RES_DONTTRUST)), is_authentic)) { + sys_restricted++; + return; /* access denied */ + } + + /* + * Do not respond if unsynchronized or stratum is below + * the floor or at or above the ceiling. + */ + if (hisleap == LEAP_NOTINSYNC || hisstratum < + sys_floor || hisstratum >= sys_ceiling) { + sys_declined++; + return; /* no help */ + } + +#ifdef AUTOKEY + /* + * Do not respond if Autokey and the opcode is not a + * CRYPTO_ASSOC response with association ID. + */ + if (crypto_flags && skeyid > NTP_MAXKEY && (opcode & + 0xffff0000) != (CRYPTO_ASSOC | CRYPTO_RESP)) { + sys_declined++; + return; /* protocol error */ + } +#endif /* AUTOKEY */ + + /* + * Broadcasts received via a multicast address may + * arrive after a unicast volley has begun + * with the same remote address. newpeer() will not + * find duplicate associations on other local endpoints + * if a non-NULL endpoint is supplied. multicastclient + * ephemeral associations are unique across all local + * endpoints. + */ + if (!(INT_MCASTOPEN & rbufp->dstadr->flags)) + match_ep = rbufp->dstadr; + else + match_ep = NULL; + + /* + * Determine whether to execute the initial volley. + */ + if (sys_bdelay != 0) { +#ifdef AUTOKEY + /* + * If a two-way exchange is not possible, + * neither is Autokey. + */ + if (crypto_flags && skeyid > NTP_MAXKEY) { + sys_restricted++; + return; /* no autokey */ + } +#endif /* AUTOKEY */ + + /* + * Do not execute the volley. Start out in + * broadcast client mode. + */ + peer = newpeer(&rbufp->recv_srcadr, NULL, + match_ep, MODE_BCLIENT, hisversion, + pkt->ppoll, pkt->ppoll, FLAG_PREEMPT, + MDF_BCLNT, 0, skeyid, sys_ident); + if (NULL == peer) { + sys_restricted++; + return; /* ignore duplicate */ + + } else { + peer->delay = sys_bdelay; + } + break; + } + + /* + * Execute the initial volley in order to calibrate the + * propagation delay and run the Autokey protocol. + * + * Note that the minpoll is taken from the broadcast + * packet, normally 6 (64 s) and that the poll interval + * is fixed at this value. + */ + peer = newpeer(&rbufp->recv_srcadr, NULL, match_ep, + MODE_CLIENT, hisversion, pkt->ppoll, pkt->ppoll, + FLAG_BC_VOL | FLAG_IBURST | FLAG_PREEMPT, MDF_BCLNT, + 0, skeyid, sys_ident); + if (NULL == peer) { + sys_restricted++; + return; /* ignore duplicate */ + } +#ifdef AUTOKEY + if (skeyid > NTP_MAXKEY) + crypto_recv(peer, rbufp); +#endif /* AUTOKEY */ + + return; /* hooray */ + + /* + * This is the first packet received from a symmetric active + * peer. If the packet is authentic and the first he sent, + * mobilize a passive association. If not, kiss the frog. + */ + case AM_NEWPASS: + +#ifdef AUTOKEY + /* + * Do not respond if not the same group. + */ + if (group_test(groupname, sys_ident)) { + sys_declined++; + return; + } +#endif /* AUTOKEY */ + if (!AUTH(sys_authenticate | (restrict_mask & + (RES_NOPEER | RES_DONTTRUST)), is_authentic)) { + + /* + * If authenticated but cannot mobilize an + * association, send a symmetric passive + * response without mobilizing an association. + * This is for drat broken Windows clients. See + * Microsoft KB 875424 for preferred workaround. + */ + if (AUTH(restrict_mask & RES_DONTTRUST, + is_authentic)) { + fast_xmit(rbufp, MODE_PASSIVE, skeyid, + restrict_mask); + return; /* hooray */ + } + if (is_authentic == AUTH_ERROR) { + fast_xmit(rbufp, MODE_ACTIVE, 0, + restrict_mask); + sys_restricted++; + } + } + + /* + * Do not respond if synchronized and if stratum is + * below the floor or at or above the ceiling. Note, + * this allows an unsynchronized peer to synchronize to + * us. It would be very strange if he did and then was + * nipped, but that could only happen if we were + * operating at the top end of the range. It also means + * we will spin an ephemeral association in response to + * MODE_ACTIVE KoDs, which will time out eventually. + */ + if (hisleap != LEAP_NOTINSYNC && (hisstratum < + sys_floor || hisstratum >= sys_ceiling)) { + sys_declined++; + return; /* no help */ + } + + /* + * The message is correctly authenticated and allowed. + * Mobilize a symmetric passive association. + */ + if ((peer = newpeer(&rbufp->recv_srcadr, NULL, + rbufp->dstadr, MODE_PASSIVE, hisversion, pkt->ppoll, + NTP_MAXDPOLL, 0, MDF_UCAST, 0, skeyid, + sys_ident)) == NULL) { + sys_declined++; + return; /* ignore duplicate */ + } + break; + + + /* + * Process regular packet. Nothing special. + */ + case AM_PROCPKT: + +#ifdef AUTOKEY + /* + * Do not respond if not the same group. + */ + if (group_test(groupname, peer->ident)) { + sys_declined++; + return; + } +#endif /* AUTOKEY */ + break; + + /* + * A passive packet matches a passive association. This is + * usually the result of reconfiguring a client on the fly. As + * this association might be legitimate and this packet an + * attempt to deny service, just ignore it. + */ + case AM_ERR: + sys_declined++; + return; + + /* + * For everything else there is the bit bucket. + */ + default: + sys_declined++; + return; + } + +#ifdef AUTOKEY + /* + * If the association is configured for Autokey, the packet must + * have a public key ID; if not, the packet must have a + * symmetric key ID. + */ + if (is_authentic != AUTH_CRYPTO && (((peer->flags & + FLAG_SKEY) && skeyid <= NTP_MAXKEY) || (!(peer->flags & + FLAG_SKEY) && skeyid > NTP_MAXKEY))) { + sys_badauth++; + return; + } +#endif /* AUTOKEY */ + peer->received++; + peer->flash &= ~PKT_TEST_MASK; + if (peer->flags & FLAG_XBOGUS) { + peer->flags &= ~FLAG_XBOGUS; + peer->flash |= TEST3; + } + + /* + * Next comes a rigorous schedule of timestamp checking. If the + * transmit timestamp is zero, the server has not initialized in + * interleaved modes or is horribly broken. + */ + if (L_ISZERO(&p_xmt)) { + peer->flash |= TEST3; /* unsynch */ + + /* + * If the transmit timestamp duplicates a previous one, the + * packet is a replay. This prevents the bad guys from replaying + * the most recent packet, authenticated or not. + */ + } else if (L_ISEQU(&peer->xmt, &p_xmt)) { + peer->flash |= TEST1; /* duplicate */ + peer->oldpkt++; + return; + + /* + * If this is a broadcast mode packet, skip further checking. If + * an initial volley, bail out now and let the client do its + * stuff. If the origin timestamp is nonzero, this is an + * interleaved broadcast. so restart the protocol. + */ + } else if (hismode == MODE_BROADCAST) { + if (!L_ISZERO(&p_org) && !(peer->flags & FLAG_XB)) { + peer->flags |= FLAG_XB; + peer->aorg = p_xmt; + peer->borg = rbufp->recv_time; + report_event(PEVNT_XLEAVE, peer, NULL); + return; + } + + /* + * Check for bogus packet in basic mode. If found, switch to + * interleaved mode and resynchronize, but only after confirming + * the packet is not bogus in symmetric interleaved mode. + */ + } else if (peer->flip == 0) { + if (!L_ISEQU(&p_org, &peer->aorg)) { + peer->bogusorg++; + peer->flash |= TEST2; /* bogus */ + if (!L_ISZERO(&peer->dst) && L_ISEQU(&p_org, + &peer->dst)) { + peer->flip = 1; + report_event(PEVNT_XLEAVE, peer, NULL); + } + } else { + L_CLR(&peer->aorg); + } + + /* + * Check for valid nonzero timestamp fields. + */ + } else if (L_ISZERO(&p_org) || L_ISZERO(&p_rec) || + L_ISZERO(&peer->dst)) { + peer->flash |= TEST3; /* unsynch */ + + /* + * Check for bogus packet in interleaved symmetric mode. This + * can happen if a packet is lost, duplicated or crossed. If + * found, flip and resynchronize. + */ + } else if (!L_ISZERO(&peer->dst) && !L_ISEQU(&p_org, + &peer->dst)) { + peer->bogusorg++; + peer->flags |= FLAG_XBOGUS; + peer->flash |= TEST2; /* bogus */ + } + + /* + * Update the state variables. + */ + if (peer->flip == 0) { + if (hismode != MODE_BROADCAST) + peer->rec = p_xmt; + peer->dst = rbufp->recv_time; + } + peer->xmt = p_xmt; + + /* + * If this is a crypto_NAK, the server cannot authenticate a + * client packet. The server might have just changed keys. Clear + * the association and restart the protocol. + */ + if (is_authentic == AUTH_CRYPTO) { + report_event(PEVNT_AUTH, peer, "crypto_NAK"); + peer->flash |= TEST5; /* bad auth */ + peer->badauth++; + if (peer->flags & FLAG_PREEMPT) { + unpeer(peer); + return; + } +#ifdef AUTOKEY + if (peer->crypto) + peer_clear(peer, "AUTH"); +#endif /* AUTOKEY */ + return; + + /* + * If the digest fails, the client cannot authenticate a server + * reply to a client packet previously sent. The loopback check + * is designed to avoid a bait-and-switch attack, which was + * possible in past versions. If symmetric modes, return a + * crypto-NAK. The peer should restart the protocol. + */ + } else if (!AUTH(has_mac || (restrict_mask & RES_DONTTRUST), + is_authentic)) { + report_event(PEVNT_AUTH, peer, "digest"); + peer->flash |= TEST5; /* bad auth */ + peer->badauth++; + if (hismode == MODE_ACTIVE || hismode == MODE_PASSIVE) + fast_xmit(rbufp, MODE_ACTIVE, 0, restrict_mask); + if (peer->flags & FLAG_PREEMPT) { + unpeer(peer); + return; + } +#ifdef AUTOKEY + if (peer->crypto) + peer_clear(peer, "AUTH"); +#endif /* AUTOKEY */ + return; + } + + /* + * Set the peer ppoll to the maximum of the packet ppoll and the + * peer minpoll. If a kiss-o'-death, set the peer minpoll to + * this maximum and advance the headway to give the sender some + * headroom. Very intricate. + */ + peer->ppoll = max(peer->minpoll, pkt->ppoll); + if (hismode == MODE_SERVER && hisleap == LEAP_NOTINSYNC && + hisstratum == STRATUM_UNSPEC && memcmp(&pkt->refid, + "RATE", 4) == 0) { + peer->selbroken++; + report_event(PEVNT_RATE, peer, NULL); + if (pkt->ppoll > peer->minpoll) + peer->minpoll = peer->ppoll; + peer->burst = peer->retry = 0; + peer->throttle = (NTP_SHIFT + 1) * (1 << peer->minpoll); + poll_update(peer, pkt->ppoll); + return; /* kiss-o'-death */ + } + + /* + * That was hard and I am sweaty, but the packet is squeaky + * clean. Get on with real work. + */ + peer->timereceived = current_time; + if (is_authentic == AUTH_OK) + peer->flags |= FLAG_AUTHENTIC; + else + peer->flags &= ~FLAG_AUTHENTIC; + +#ifdef AUTOKEY + /* + * More autokey dance. The rules of the cha-cha are as follows: + * + * 1. If there is no key or the key is not auto, do nothing. + * + * 2. If this packet is in response to the one just previously + * sent or from a broadcast server, do the extension fields. + * Otherwise, assume bogosity and bail out. + * + * 3. If an extension field contains a verified signature, it is + * self-authenticated and we sit the dance. + * + * 4. If this is a server reply, check only to see that the + * transmitted key ID matches the received key ID. + * + * 5. Check to see that one or more hashes of the current key ID + * matches the previous key ID or ultimate original key ID + * obtained from the broadcaster or symmetric peer. If no + * match, sit the dance and call for new autokey values. + * + * In case of crypto error, fire the orchestra, stop dancing and + * restart the protocol. + */ + if (peer->flags & FLAG_SKEY) { + /* + * Decrement remaining autokey hashes. This isn't + * perfect if a packet is lost, but results in no harm. + */ + ap = (struct autokey *)peer->recval.ptr; + if (ap != NULL) { + if (ap->seq > 0) + ap->seq--; + } + peer->flash |= TEST8; + rval = crypto_recv(peer, rbufp); + if (rval == XEVNT_OK) { + peer->unreach = 0; + } else { + if (rval == XEVNT_ERR) { + report_event(PEVNT_RESTART, peer, + "crypto error"); + peer_clear(peer, "CRYP"); + peer->flash |= TEST9; /* bad crypt */ + if (peer->flags & FLAG_PREEMPT) + unpeer(peer); + } + return; + } + + /* + * If server mode, verify the receive key ID matches + * the transmit key ID. + */ + if (hismode == MODE_SERVER) { + if (skeyid == peer->keyid) + peer->flash &= ~TEST8; + + /* + * If an extension field is present, verify only that it + * has been correctly signed. We don't need a sequence + * check here, but the sequence continues. + */ + } else if (!(peer->flash & TEST8)) { + peer->pkeyid = skeyid; + + /* + * Now the fun part. Here, skeyid is the current ID in + * the packet, pkeyid is the ID in the last packet and + * tkeyid is the hash of skeyid. If the autokey values + * have not been received, this is an automatic error. + * If so, check that the tkeyid matches pkeyid. If not, + * hash tkeyid and try again. If the number of hashes + * exceeds the number remaining in the sequence, declare + * a successful failure and refresh the autokey values. + */ + } else if (ap != NULL) { + int i; + + for (i = 0; ; i++) { + if (tkeyid == peer->pkeyid || + tkeyid == ap->key) { + peer->flash &= ~TEST8; + peer->pkeyid = skeyid; + ap->seq -= i; + break; + } + if (i > ap->seq) { + peer->crypto &= + ~CRYPTO_FLAG_AUTO; + break; + } + tkeyid = session_key( + &rbufp->recv_srcadr, dstadr_sin, + tkeyid, pkeyid, 0); + } + if (peer->flash & TEST8) + report_event(PEVNT_AUTH, peer, "keylist"); + } + if (!(peer->crypto & CRYPTO_FLAG_PROV)) /* test 9 */ + peer->flash |= TEST8; /* bad autokey */ + + /* + * The maximum lifetime of the protocol is about one + * week before restarting the Autokey protocol to + * refresh certificates and leapseconds values. + */ + if (current_time > peer->refresh) { + report_event(PEVNT_RESTART, peer, + "crypto refresh"); + peer_clear(peer, "TIME"); + return; + } + } +#endif /* AUTOKEY */ + + /* + * The dance is complete and the flash bits have been lit. Toss + * the packet over the fence for processing, which may light up + * more flashers. + */ + process_packet(peer, pkt, rbufp->recv_length); + + /* + * In interleaved mode update the state variables. Also adjust the + * transmit phase to avoid crossover. + */ + if (peer->flip != 0) { + peer->rec = p_rec; + peer->dst = rbufp->recv_time; + if (peer->nextdate - current_time < (1U << min(peer->ppoll, + peer->hpoll)) / 2) + peer->nextdate++; + else + peer->nextdate--; + } +} + + +/* + * process_packet - Packet Procedure, a la Section 3.4.4 of the + * specification. Or almost, at least. If we're in here we have a + * reasonable expectation that we will be having a long term + * relationship with this host. + */ +void +process_packet( + register struct peer *peer, + register struct pkt *pkt, + u_int len + ) +{ + double t34, t21; + double p_offset, p_del, p_disp; + l_fp p_rec, p_xmt, p_org, p_reftime, ci; + u_char pmode, pleap, pversion, pstratum; + char statstr[NTP_MAXSTRLEN]; +#ifdef ASSYM + int itemp; + double etemp, ftemp, td; +#endif /* ASSYM */ + + sys_processed++; + peer->processed++; + p_del = FPTOD(NTOHS_FP(pkt->rootdelay)); + p_offset = 0; + p_disp = FPTOD(NTOHS_FP(pkt->rootdisp)); + NTOHL_FP(&pkt->reftime, &p_reftime); + NTOHL_FP(&pkt->org, &p_org); + NTOHL_FP(&pkt->rec, &p_rec); + NTOHL_FP(&pkt->xmt, &p_xmt); + pmode = PKT_MODE(pkt->li_vn_mode); + pleap = PKT_LEAP(pkt->li_vn_mode); + pversion = PKT_VERSION(pkt->li_vn_mode); + pstratum = PKT_TO_STRATUM(pkt->stratum); + + /* + * Capture the header values in the client/peer association.. + */ + record_raw_stats(&peer->srcadr, peer->dstadr ? + &peer->dstadr->sin : NULL, + &p_org, &p_rec, &p_xmt, &peer->dst, + pleap, pversion, pmode, pstratum, pkt->ppoll, pkt->precision, + p_del, p_disp, pkt->refid); + peer->leap = pleap; + peer->stratum = min(pstratum, STRATUM_UNSPEC); + peer->pmode = pmode; + peer->precision = pkt->precision; + peer->rootdelay = p_del; + peer->rootdisp = p_disp; + peer->refid = pkt->refid; /* network byte order */ + peer->reftime = p_reftime; + + /* + * First, if either burst mode is armed, enable the burst. + * Compute the headway for the next packet and delay if + * necessary to avoid exceeding the threshold. + */ + if (peer->retry > 0) { + peer->retry = 0; + if (peer->reach) + peer->burst = min(1 << (peer->hpoll - + peer->minpoll), NTP_SHIFT) - 1; + else + peer->burst = NTP_IBURST - 1; + if (peer->burst > 0) + peer->nextdate = current_time; + } + poll_update(peer, peer->hpoll); + + /* + * Verify the server is synchronized; that is, the leap bits, + * stratum and root distance are valid. + */ + if (pleap == LEAP_NOTINSYNC || /* test 6 */ + pstratum < sys_floor || pstratum >= sys_ceiling) + peer->flash |= TEST6; /* bad synch or strat */ + if (p_del / 2 + p_disp >= MAXDISPERSE) /* test 7 */ + peer->flash |= TEST7; /* bad header */ + + /* + * If any tests fail at this point, the packet is discarded. + * Note that some flashers may have already been set in the + * receive() routine. + */ + if (peer->flash & PKT_TEST_MASK) { + peer->seldisptoolarge++; +#ifdef DEBUG + if (debug) + printf("packet: flash header %04x\n", + peer->flash); +#endif + return; + } + + /* + * If the peer was previously unreachable, raise a trap. In any + * case, mark it reachable. + */ + if (!peer->reach) { + report_event(PEVNT_REACH, peer, NULL); + peer->timereachable = current_time; + } + peer->reach |= 1; + + /* + * For a client/server association, calculate the clock offset, + * roundtrip delay and dispersion. The equations are reordered + * from the spec for more efficient use of temporaries. For a + * broadcast association, offset the last measurement by the + * computed delay during the client/server volley. Note the + * computation of dispersion includes the system precision plus + * that due to the frequency error since the origin time. + * + * It is very important to respect the hazards of overflow. The + * only permitted operation on raw timestamps is subtraction, + * where the result is a signed quantity spanning from 68 years + * in the past to 68 years in the future. To avoid loss of + * precision, these calculations are done using 64-bit integer + * arithmetic. However, the offset and delay calculations are + * sums and differences of these first-order differences, which + * if done using 64-bit integer arithmetic, would be valid over + * only half that span. Since the typical first-order + * differences are usually very small, they are converted to 64- + * bit doubles and all remaining calculations done in floating- + * double arithmetic. This preserves the accuracy while + * retaining the 68-year span. + * + * There are three interleaving schemes, basic, interleaved + * symmetric and interleaved broadcast. The timestamps are + * idioscyncratically different. See the onwire briefing/white + * paper at www.eecis.udel.edu/~mills for details. + * + * Interleaved symmetric mode + * t1 = peer->aorg/borg, t2 = peer->rec, t3 = p_xmt, + * t4 = peer->dst + */ + if (peer->flip != 0) { + ci = p_xmt; /* t3 - t4 */ + L_SUB(&ci, &peer->dst); + LFPTOD(&ci, t34); + ci = p_rec; /* t2 - t1 */ + if (peer->flip > 0) + L_SUB(&ci, &peer->borg); + else + L_SUB(&ci, &peer->aorg); + LFPTOD(&ci, t21); + p_del = t21 - t34; + p_offset = (t21 + t34) / 2.; + if (p_del < 0 || p_del > 1.) { + snprintf(statstr, sizeof(statstr), + "t21 %.6f t34 %.6f", t21, t34); + report_event(PEVNT_XERR, peer, statstr); + return; + } + + /* + * Broadcast modes + */ + } else if (peer->pmode == MODE_BROADCAST) { + + /* + * Interleaved broadcast mode. Use interleaved timestamps. + * t1 = peer->borg, t2 = p_org, t3 = p_org, t4 = aorg + */ + if (peer->flags & FLAG_XB) { + ci = p_org; /* delay */ + L_SUB(&ci, &peer->aorg); + LFPTOD(&ci, t34); + ci = p_org; /* t2 - t1 */ + L_SUB(&ci, &peer->borg); + LFPTOD(&ci, t21); + peer->aorg = p_xmt; + peer->borg = peer->dst; + if (t34 < 0 || t34 > 1.) { + snprintf(statstr, sizeof(statstr), + "offset %.6f delay %.6f", t21, t34); + report_event(PEVNT_XERR, peer, statstr); + return; + } + p_offset = t21; + peer->xleave = t34; + + /* + * Basic broadcast - use direct timestamps. + * t3 = p_xmt, t4 = peer->dst + */ + } else { + ci = p_xmt; /* t3 - t4 */ + L_SUB(&ci, &peer->dst); + LFPTOD(&ci, t34); + p_offset = t34; + } + + /* + * When calibration is complete and the clock is + * synchronized, the bias is calculated as the difference + * between the unicast timestamp and the broadcast + * timestamp. This works for both basic and interleaved + * modes. + */ + if (FLAG_BC_VOL & peer->flags) { + peer->flags &= ~FLAG_BC_VOL; + peer->delay = fabs(peer->offset - p_offset) * 2; + } + p_del = peer->delay; + p_offset += p_del / 2; + + + /* + * Basic mode, otherwise known as the old fashioned way. + * + * t1 = p_org, t2 = p_rec, t3 = p_xmt, t4 = peer->dst + */ + } else { + ci = p_xmt; /* t3 - t4 */ + L_SUB(&ci, &peer->dst); + LFPTOD(&ci, t34); + ci = p_rec; /* t2 - t1 */ + L_SUB(&ci, &p_org); + LFPTOD(&ci, t21); + p_del = fabs(t21 - t34); + p_offset = (t21 + t34) / 2.; + } + p_del = max(p_del, LOGTOD(sys_precision)); + p_disp = LOGTOD(sys_precision) + LOGTOD(peer->precision) + + clock_phi * p_del; + +#if ASSYM + /* + * This code calculates the outbound and inbound data rates by + * measuring the differences between timestamps at different + * packet lengths. This is helpful in cases of large asymmetric + * delays commonly experienced on deep space communication + * links. + */ + if (peer->t21_last > 0 && peer->t34_bytes > 0) { + itemp = peer->t21_bytes - peer->t21_last; + if (itemp > 25) { + etemp = t21 - peer->t21; + if (fabs(etemp) > 1e-6) { + ftemp = itemp / etemp; + if (ftemp > 1000.) + peer->r21 = ftemp; + } + } + itemp = len - peer->t34_bytes; + if (itemp > 25) { + etemp = -t34 - peer->t34; + if (fabs(etemp) > 1e-6) { + ftemp = itemp / etemp; + if (ftemp > 1000.) + peer->r34 = ftemp; + } + } + } + + /* + * The following section compensates for different data rates on + * the outbound (d21) and inbound (t34) directions. To do this, + * it finds t such that r21 * t - r34 * (d - t) = 0, where d is + * the roundtrip delay. Then it calculates the correction as a + * fraction of d. + */ + peer->t21 = t21; + peer->t21_last = peer->t21_bytes; + peer->t34 = -t34; + peer->t34_bytes = len; +#ifdef DEBUG + if (debug > 1) + printf("packet: t21 %.9lf %d t34 %.9lf %d\n", peer->t21, + peer->t21_bytes, peer->t34, peer->t34_bytes); +#endif + if (peer->r21 > 0 && peer->r34 > 0 && p_del > 0) { + if (peer->pmode != MODE_BROADCAST) + td = (peer->r34 / (peer->r21 + peer->r34) - + .5) * p_del; + else + td = 0; + + /* + * Unfortunately, in many cases the errors are + * unacceptable, so for the present the rates are not + * used. In future, we might find conditions where the + * calculations are useful, so this should be considered + * a work in progress. + */ + t21 -= td; + t34 -= td; +#ifdef DEBUG + if (debug > 1) + printf("packet: del %.6lf r21 %.1lf r34 %.1lf %.6lf\n", + p_del, peer->r21 / 1e3, peer->r34 / 1e3, + td); +#endif + } +#endif /* ASSYM */ + + /* + * That was awesome. Now hand off to the clock filter. + */ + clock_filter(peer, p_offset + peer->bias, p_del, p_disp); + + /* + * If we are in broadcast calibrate mode, return to broadcast + * client mode when the client is fit and the autokey dance is + * complete. + */ + if ((FLAG_BC_VOL & peer->flags) && MODE_CLIENT == peer->hmode && + !(TEST11 & peer_unfit(peer))) { /* distance exceeded */ +#ifdef AUTOKEY + if (peer->flags & FLAG_SKEY) { + if (!(~peer->crypto & CRYPTO_FLAG_ALL)) + peer->hmode = MODE_BCLIENT; + } else { + peer->hmode = MODE_BCLIENT; + } +#else /* !AUTOKEY follows */ + peer->hmode = MODE_BCLIENT; +#endif /* !AUTOKEY */ + } +} + + +/* + * clock_update - Called at system process update intervals. + */ +static void +clock_update( + struct peer *peer /* peer structure pointer */ + ) +{ + double dtemp; + l_fp now; +#ifdef HAVE_LIBSCF_H + char *fmri; +#endif /* HAVE_LIBSCF_H */ + + /* + * Update the system state variables. We do this very carefully, + * as the poll interval might need to be clamped differently. + */ + sys_peer = peer; + sys_epoch = peer->epoch; + if (sys_poll < peer->minpoll) + sys_poll = peer->minpoll; + if (sys_poll > peer->maxpoll) + sys_poll = peer->maxpoll; + poll_update(peer, sys_poll); + sys_stratum = min(peer->stratum + 1, STRATUM_UNSPEC); + if (peer->stratum == STRATUM_REFCLOCK || + peer->stratum == STRATUM_UNSPEC) + sys_refid = peer->refid; + else + sys_refid = addr2refid(&peer->srcadr); + /* + * Root Dispersion (E) is defined (in RFC 5905) as: + * + * E = p.epsilon_r + p.epsilon + p.psi + PHI*(s.t - p.t) + |THETA| + * + * where: + * p.epsilon_r is the PollProc's root dispersion + * p.epsilon is the PollProc's dispersion + * p.psi is the PollProc's jitter + * THETA is the combined offset + * + * NB: Think Hard about where these numbers come from and + * what they mean. When did peer->update happen? Has anything + * interesting happened since then? What values are the most + * defensible? Why? + * + * DLM thinks this equation is probably the best of all worse choices. + */ + dtemp = peer->rootdisp + + peer->disp + + sys_jitter + + clock_phi * (current_time - peer->update) + + fabs(sys_offset); + + if (dtemp > sys_mindisp) + sys_rootdisp = dtemp; + else + sys_rootdisp = sys_mindisp; + sys_rootdelay = peer->delay + peer->rootdelay; + sys_reftime = peer->dst; + +#ifdef DEBUG + if (debug) + printf( + "clock_update: at %lu sample %lu associd %d\n", + current_time, peer->epoch, peer->associd); +#endif + + /* + * Comes now the moment of truth. Crank the clock discipline and + * see what comes out. + */ + switch (local_clock(peer, sys_offset)) { + + /* + * Clock exceeds panic threshold. Life as we know it ends. + */ + case -1: +#ifdef HAVE_LIBSCF_H + /* + * For Solaris enter the maintenance mode. + */ + if ((fmri = getenv("SMF_FMRI")) != NULL) { + if (smf_maintain_instance(fmri, 0) < 0) { + printf("smf_maintain_instance: %s\n", + scf_strerror(scf_error())); + exit(1); + } + /* + * Sleep until SMF kills us. + */ + for (;;) + pause(); + } +#endif /* HAVE_LIBSCF_H */ + exit (-1); + /* not reached */ + + /* + * Clock was stepped. Flush all time values of all peers. + */ + case 2: + clear_all(); + sys_leap = LEAP_NOTINSYNC; + sys_stratum = STRATUM_UNSPEC; + memcpy(&sys_refid, "STEP", 4); + sys_rootdelay = 0; + sys_rootdisp = 0; + L_CLR(&sys_reftime); + sys_jitter = LOGTOD(sys_precision); + leapsec_reset_frame(); + break; + + /* + * Clock was slewed. Handle the leapsecond stuff. + */ + case 1: + + /* + * If this is the first time the clock is set, reset the + * leap bits. If crypto, the timer will goose the setup + * process. + */ + if (sys_leap == LEAP_NOTINSYNC) { + sys_leap = LEAP_NOWARNING; +#ifdef AUTOKEY + if (crypto_flags) + crypto_update(); +#endif /* AUTOKEY */ + /* + * If our parent process is waiting for the + * first clock sync, send them home satisfied. + */ +#ifdef HAVE_WORKING_FORK + if (waitsync_fd_to_close != -1) { + close(waitsync_fd_to_close); + waitsync_fd_to_close = -1; + DPRINTF(1, ("notified parent --wait-sync is done\n")); + } +#endif /* HAVE_WORKING_FORK */ + + } + + /* + * If there is no leap second pending and the number of + * survivor leap bits is greater than half the number of + * survivors, try to schedule a leap for the end of the + * current month. (This only works if no leap second for + * that range is in the table, so doing this more than + * once is mostly harmless.) + */ + if (leapsec == LSPROX_NOWARN) { + if (leap_vote_ins > leap_vote_del + && leap_vote_ins > sys_survivors / 2) { + get_systime(&now); + leapsec_add_dyn(TRUE, now.l_ui, NULL); + } + if (leap_vote_del > leap_vote_ins + && leap_vote_del > sys_survivors / 2) { + get_systime(&now); + leapsec_add_dyn(FALSE, now.l_ui, NULL); + } + } + break; + + /* + * Popcorn spike or step threshold exceeded. Pretend it never + * happened. + */ + default: + break; + } +} + + +/* + * poll_update - update peer poll interval + */ +void +poll_update( + struct peer *peer, /* peer structure pointer */ + u_char mpoll + ) +{ + u_long next, utemp; + u_char hpoll; + + /* + * This routine figures out when the next poll should be sent. + * That turns out to be wickedly complicated. One problem is + * that sometimes the time for the next poll is in the past when + * the poll interval is reduced. We watch out for races here + * between the receive process and the poll process. + * + * Clamp the poll interval between minpoll and maxpoll. + */ + hpoll = max(min(peer->maxpoll, mpoll), peer->minpoll); + +#ifdef AUTOKEY + /* + * If during the crypto protocol the poll interval has changed, + * the lifetimes in the key list are probably bogus. Purge the + * the key list and regenerate it later. + */ + if ((peer->flags & FLAG_SKEY) && hpoll != peer->hpoll) + key_expire(peer); +#endif /* AUTOKEY */ + peer->hpoll = hpoll; + + /* + * There are three variables important for poll scheduling, the + * current time (current_time), next scheduled time (nextdate) + * and the earliest time (utemp). The earliest time is 2 s + * seconds, but could be more due to rate management. When + * sending in a burst, use the earliest time. When not in a + * burst but with a reply pending, send at the earliest time + * unless the next scheduled time has not advanced. This can + * only happen if multiple replies are pending in the same + * response interval. Otherwise, send at the later of the next + * scheduled time and the earliest time. + * + * Now we figure out if there is an override. If a burst is in + * progress and we get called from the receive process, just + * slink away. If called from the poll process, delay 1 s for a + * reference clock, otherwise 2 s. + */ + utemp = current_time + max(peer->throttle - (NTP_SHIFT - 1) * + (1 << peer->minpoll), ntp_minpkt); + if (peer->burst > 0) { + if (peer->nextdate > current_time) + return; +#ifdef REFCLOCK + else if (peer->flags & FLAG_REFCLOCK) + peer->nextdate = current_time + RESP_DELAY; +#endif /* REFCLOCK */ + else + peer->nextdate = utemp; + +#ifdef AUTOKEY + /* + * If a burst is not in progress and a crypto response message + * is pending, delay 2 s, but only if this is a new interval. + */ + } else if (peer->cmmd != NULL) { + if (peer->nextdate > current_time) { + if (peer->nextdate + ntp_minpkt != utemp) + peer->nextdate = utemp; + } else { + peer->nextdate = utemp; + } +#endif /* AUTOKEY */ + + /* + * The ordinary case. If a retry, use minpoll; if unreachable, + * use host poll; otherwise, use the minimum of host and peer + * polls; In other words, oversampling is okay but + * understampling is evil. Use the maximum of this value and the + * headway. If the average headway is greater than the headway + * threshold, increase the headway by the minimum interval. + */ + } else { + if (peer->retry > 0) + hpoll = peer->minpoll; + else if (!(peer->reach)) + hpoll = peer->hpoll; + else + hpoll = min(peer->ppoll, peer->hpoll); +#ifdef REFCLOCK + if (peer->flags & FLAG_REFCLOCK) + next = 1 << hpoll; + else +#endif /* REFCLOCK */ + next = ((0x1000UL | (ntp_random() & 0x0ff)) << + hpoll) >> 12; + next += peer->outdate; + if (next > utemp) + peer->nextdate = next; + else + peer->nextdate = utemp; + if (peer->throttle > (1 << peer->minpoll)) + peer->nextdate += ntp_minpkt; + } + DPRINTF(2, ("poll_update: at %lu %s poll %d burst %d retry %d head %d early %lu next %lu\n", + current_time, ntoa(&peer->srcadr), peer->hpoll, + peer->burst, peer->retry, peer->throttle, + utemp - current_time, peer->nextdate - + current_time)); +} + + +/* + * peer_clear - clear peer filter registers. See Section 3.4.8 of the + * spec. + */ +void +peer_clear( + struct peer *peer, /* peer structure */ + char *ident /* tally lights */ + ) +{ + u_char u; + +#ifdef AUTOKEY + /* + * If cryptographic credentials have been acquired, toss them to + * Valhalla. Note that autokeys are ephemeral, in that they are + * tossed immediately upon use. Therefore, the keylist can be + * purged anytime without needing to preserve random keys. Note + * that, if the peer is purged, the cryptographic variables are + * purged, too. This makes it much harder to sneak in some + * unauthenticated data in the clock filter. + */ + key_expire(peer); + if (peer->iffval != NULL) + BN_free(peer->iffval); + value_free(&peer->cookval); + value_free(&peer->recval); + value_free(&peer->encrypt); + value_free(&peer->sndval); + if (peer->cmmd != NULL) + free(peer->cmmd); + if (peer->subject != NULL) + free(peer->subject); + if (peer->issuer != NULL) + free(peer->issuer); +#endif /* AUTOKEY */ + + /* + * Clear all values, including the optional crypto values above. + */ + memset(CLEAR_TO_ZERO(peer), 0, LEN_CLEAR_TO_ZERO(peer)); + peer->ppoll = peer->maxpoll; + peer->hpoll = peer->minpoll; + peer->disp = MAXDISPERSE; + peer->flash = peer_unfit(peer); + peer->jitter = LOGTOD(sys_precision); + + /* + * If interleave mode, initialize the alternate origin switch. + */ + if (peer->flags & FLAG_XLEAVE) + peer->flip = 1; + for (u = 0; u < NTP_SHIFT; u++) { + peer->filter_order[u] = u; + peer->filter_disp[u] = MAXDISPERSE; + } +#ifdef REFCLOCK + if (!(peer->flags & FLAG_REFCLOCK)) { +#endif + peer->leap = LEAP_NOTINSYNC; + peer->stratum = STRATUM_UNSPEC; + memcpy(&peer->refid, ident, 4); +#ifdef REFCLOCK + } +#endif + + /* + * During initialization use the association count to spread out + * the polls at one-second intervals. Passive associations' + * first poll is delayed by the "discard minimum" to avoid rate + * limiting. Other post-startup new or cleared associations + * randomize the first poll over the minimum poll interval to + * avoid implosion. + */ + peer->nextdate = peer->update = peer->outdate = current_time; + if (initializing) { + peer->nextdate += peer_associations; + } else if (MODE_PASSIVE == peer->hmode) { + peer->nextdate += ntp_minpkt; + } else { + peer->nextdate += ntp_random() % peer->minpoll; + } +#ifdef AUTOKEY + peer->refresh = current_time + (1 << NTP_REFRESH); +#endif /* AUTOKEY */ +#ifdef DEBUG + if (debug) + printf( + "peer_clear: at %ld next %ld associd %d refid %s\n", + current_time, peer->nextdate, peer->associd, + ident); +#endif +} + + +/* + * clock_filter - add incoming clock sample to filter register and run + * the filter procedure to find the best sample. + */ +void +clock_filter( + struct peer *peer, /* peer structure pointer */ + double sample_offset, /* clock offset */ + double sample_delay, /* roundtrip delay */ + double sample_disp /* dispersion */ + ) +{ + double dst[NTP_SHIFT]; /* distance vector */ + int ord[NTP_SHIFT]; /* index vector */ + int i, j, k, m; + double dtemp, etemp; + char tbuf[80]; + + /* + * A sample consists of the offset, delay, dispersion and epoch + * of arrival. The offset and delay are determined by the on- + * wire protocol. The dispersion grows from the last outbound + * packet to the arrival of this one increased by the sum of the + * peer precision and the system precision as required by the + * error budget. First, shift the new arrival into the shift + * register discarding the oldest one. + */ + j = peer->filter_nextpt; + peer->filter_offset[j] = sample_offset; + peer->filter_delay[j] = sample_delay; + peer->filter_disp[j] = sample_disp; + peer->filter_epoch[j] = current_time; + j = (j + 1) % NTP_SHIFT; + peer->filter_nextpt = j; + + /* + * Update dispersions since the last update and at the same + * time initialize the distance and index lists. Since samples + * become increasingly uncorrelated beyond the Allan intercept, + * only under exceptional cases will an older sample be used. + * Therefore, the distance list uses a compound metric. If the + * dispersion is greater than the maximum dispersion, clamp the + * distance at that value. If the time since the last update is + * less than the Allan intercept use the delay; otherwise, use + * the sum of the delay and dispersion. + */ + dtemp = clock_phi * (current_time - peer->update); + peer->update = current_time; + for (i = NTP_SHIFT - 1; i >= 0; i--) { + if (i != 0) + peer->filter_disp[j] += dtemp; + if (peer->filter_disp[j] >= MAXDISPERSE) { + peer->filter_disp[j] = MAXDISPERSE; + dst[i] = MAXDISPERSE; + } else if (peer->update - peer->filter_epoch[j] > + (u_long)ULOGTOD(allan_xpt)) { + dst[i] = peer->filter_delay[j] + + peer->filter_disp[j]; + } else { + dst[i] = peer->filter_delay[j]; + } + ord[i] = j; + j = (j + 1) % NTP_SHIFT; + } + + /* + * If the clock has stabilized, sort the samples by distance. + */ + if (freq_cnt == 0) { + for (i = 1; i < NTP_SHIFT; i++) { + for (j = 0; j < i; j++) { + if (dst[j] > dst[i]) { + k = ord[j]; + ord[j] = ord[i]; + ord[i] = k; + etemp = dst[j]; + dst[j] = dst[i]; + dst[i] = etemp; + } + } + } + } + + /* + * Copy the index list to the association structure so ntpq + * can see it later. Prune the distance list to leave only + * samples less than the maximum dispersion, which disfavors + * uncorrelated samples older than the Allan intercept. To + * further improve the jitter estimate, of the remainder leave + * only samples less than the maximum distance, but keep at + * least two samples for jitter calculation. + */ + m = 0; + for (i = 0; i < NTP_SHIFT; i++) { + peer->filter_order[i] = (u_char) ord[i]; + if (dst[i] >= MAXDISPERSE || (m >= 2 && dst[i] >= + sys_maxdist)) + continue; + m++; + } + + /* + * Compute the dispersion and jitter. The dispersion is weighted + * exponentially by NTP_FWEIGHT (0.5) so it is normalized close + * to 1.0. The jitter is the RMS differences relative to the + * lowest delay sample. + */ + peer->disp = peer->jitter = 0; + k = ord[0]; + for (i = NTP_SHIFT - 1; i >= 0; i--) { + j = ord[i]; + peer->disp = NTP_FWEIGHT * (peer->disp + + peer->filter_disp[j]); + if (i < m) + peer->jitter += DIFF(peer->filter_offset[j], + peer->filter_offset[k]); + } + + /* + * If no acceptable samples remain in the shift register, + * quietly tiptoe home leaving only the dispersion. Otherwise, + * save the offset, delay and jitter. Note the jitter must not + * be less than the precision. + */ + if (m == 0) { + clock_select(); + return; + } + etemp = fabs(peer->offset - peer->filter_offset[k]); + peer->offset = peer->filter_offset[k]; + peer->delay = peer->filter_delay[k]; + if (m > 1) + peer->jitter /= m - 1; + peer->jitter = max(SQRT(peer->jitter), LOGTOD(sys_precision)); + + /* + * If the the new sample and the current sample are both valid + * and the difference between their offsets exceeds CLOCK_SGATE + * (3) times the jitter and the interval between them is less + * than twice the host poll interval, consider the new sample + * a popcorn spike and ignore it. + */ + if (peer->disp < sys_maxdist && peer->filter_disp[k] < + sys_maxdist && etemp > CLOCK_SGATE * peer->jitter && + peer->filter_epoch[k] - peer->epoch < 2. * + ULOGTOD(peer->hpoll)) { + snprintf(tbuf, sizeof(tbuf), "%.6f s", etemp); + report_event(PEVNT_POPCORN, peer, tbuf); + return; + } + + /* + * A new minimum sample is useful only if it is later than the + * last one used. In this design the maximum lifetime of any + * sample is not greater than eight times the poll interval, so + * the maximum interval between minimum samples is eight + * packets. + */ + if (peer->filter_epoch[k] <= peer->epoch) { +#if DEBUG + if (debug > 1) + printf("clock_filter: old sample %lu\n", current_time - + peer->filter_epoch[k]); +#endif + return; + } + peer->epoch = peer->filter_epoch[k]; + + /* + * The mitigated sample statistics are saved for later + * processing. If not synchronized or not in a burst, tickle the + * clock select algorithm. + */ + record_peer_stats(&peer->srcadr, ctlpeerstatus(peer), + peer->offset, peer->delay, peer->disp, peer->jitter); +#ifdef DEBUG + if (debug) + printf( + "clock_filter: n %d off %.6f del %.6f dsp %.6f jit %.6f\n", + m, peer->offset, peer->delay, peer->disp, + peer->jitter); +#endif + if (peer->burst == 0 || sys_leap == LEAP_NOTINSYNC) + clock_select(); +} + + +/* + * clock_select - find the pick-of-the-litter clock + * + * LOCKCLOCK: (1) If the local clock is the prefer peer, it will always + * be enabled, even if declared falseticker, (2) only the prefer peer + * can be selected as the system peer, (3) if the external source is + * down, the system leap bits are set to 11 and the stratum set to + * infinity. + */ +void +clock_select(void) +{ + struct peer *peer; + int i, j, k, n; + int nlist, nl2; + int allow, osurv; + int speer; + double d, e, f, g; + double high, low; + double speermet; + double orphmet = 2.0 * U_INT32_MAX; /* 2x is greater than */ + struct endpoint endp; + struct peer *osys_peer; + struct peer *sys_prefer = NULL; /* prefer peer */ + struct peer *typesystem = NULL; + struct peer *typeorphan = NULL; +#ifdef REFCLOCK + struct peer *typeacts = NULL; + struct peer *typelocal = NULL; + struct peer *typepps = NULL; +#endif /* REFCLOCK */ + static struct endpoint *endpoint = NULL; + static int *indx = NULL; + static peer_select *peers = NULL; + static u_int endpoint_size = 0; + static u_int peers_size = 0; + static u_int indx_size = 0; + size_t octets; + + /* + * Initialize and create endpoint, index and peer lists big + * enough to handle all associations. + */ + osys_peer = sys_peer; + osurv = sys_survivors; + sys_survivors = 0; +#ifdef LOCKCLOCK + sys_leap = LEAP_NOTINSYNC; + sys_stratum = STRATUM_UNSPEC; + memcpy(&sys_refid, "DOWN", 4); +#endif /* LOCKCLOCK */ + + /* + * Allocate dynamic space depending on the number of + * associations. + */ + nlist = 1; + for (peer = peer_list; peer != NULL; peer = peer->p_link) + nlist++; + endpoint_size = ALIGNED_SIZE(nlist * 2 * sizeof(*endpoint)); + peers_size = ALIGNED_SIZE(nlist * sizeof(*peers)); + indx_size = ALIGNED_SIZE(nlist * 2 * sizeof(*indx)); + octets = endpoint_size + peers_size + indx_size; + endpoint = erealloc(endpoint, octets); + peers = INC_ALIGNED_PTR(endpoint, endpoint_size); + indx = INC_ALIGNED_PTR(peers, peers_size); + + /* + * Initially, we populate the island with all the rifraff peers + * that happen to be lying around. Those with seriously + * defective clocks are immediately booted off the island. Then, + * the falsetickers are culled and put to sea. The truechimers + * remaining are subject to repeated rounds where the most + * unpopular at each round is kicked off. When the population + * has dwindled to sys_minclock, the survivors split a million + * bucks and collectively crank the chimes. + */ + nlist = nl2 = 0; /* none yet */ + for (peer = peer_list; peer != NULL; peer = peer->p_link) { + peer->new_status = CTL_PST_SEL_REJECT; + + /* + * Leave the island immediately if the peer is + * unfit to synchronize. + */ + if (peer_unfit(peer)) + continue; + + /* + * If this peer is an orphan parent, elect the + * one with the lowest metric defined as the + * IPv4 address or the first 64 bits of the + * hashed IPv6 address. To ensure convergence + * on the same selected orphan, consider as + * well that this system may have the lowest + * metric and be the orphan parent. If this + * system wins, sys_peer will be NULL to trigger + * orphan mode in timer(). + */ + if (peer->stratum == sys_orphan) { + u_int32 localmet; + u_int32 peermet; + + if (peer->dstadr != NULL) + localmet = ntohl(peer->dstadr->addr_refid); + else + localmet = U_INT32_MAX; + peermet = ntohl(addr2refid(&peer->srcadr)); + if (peermet < localmet && peermet < orphmet) { + typeorphan = peer; + orphmet = peermet; + } + continue; + } + + /* + * If this peer could have the orphan parent + * as a synchronization ancestor, exclude it + * from selection to avoid forming a + * synchronization loop within the orphan mesh, + * triggering stratum climb to infinity + * instability. Peers at stratum higher than + * the orphan stratum could have the orphan + * parent in ancestry so are excluded. + * See http://bugs.ntp.org/2050 + */ + if (peer->stratum > sys_orphan) + continue; +#ifdef REFCLOCK + /* + * The following are special cases. We deal + * with them later. + */ + if (!(peer->flags & FLAG_PREFER)) { + switch (peer->refclktype) { + case REFCLK_LOCALCLOCK: + if (current_time > orphwait && + typelocal == NULL) + typelocal = peer; + continue; + + case REFCLK_ACTS: + if (current_time > orphwait && + typeacts == NULL) + typeacts = peer; + continue; + } + } +#endif /* REFCLOCK */ + + /* + * If we get this far, the peer can stay on the + * island, but does not yet have the immunity + * idol. + */ + peer->new_status = CTL_PST_SEL_SANE; + f = root_distance(peer); + peers[nlist].peer = peer; + peers[nlist].error = peer->jitter; + peers[nlist].synch = f; + nlist++; + + /* + * Insert each interval endpoint on the unsorted + * endpoint[] list. + */ + e = peer->offset; + endpoint[nl2].type = -1; /* lower end */ + endpoint[nl2].val = e - f; + nl2++; + endpoint[nl2].type = 1; /* upper end */ + endpoint[nl2].val = e + f; + nl2++; + } + /* + * Construct sorted indx[] of endpoint[] indexes ordered by + * offset. + */ + for (i = 0; i < nl2; i++) + indx[i] = i; + for (i = 0; i < nl2; i++) { + endp = endpoint[indx[i]]; + e = endp.val; + k = i; + for (j = i + 1; j < nl2; j++) { + endp = endpoint[indx[j]]; + if (endp.val < e) { + e = endp.val; + k = j; + } + } + if (k != i) { + j = indx[k]; + indx[k] = indx[i]; + indx[i] = j; + } + } + for (i = 0; i < nl2; i++) + DPRINTF(3, ("select: endpoint %2d %.6f\n", + endpoint[indx[i]].type, endpoint[indx[i]].val)); + + /* + * This is the actual algorithm that cleaves the truechimers + * from the falsetickers. The original algorithm was described + * in Keith Marzullo's dissertation, but has been modified for + * better accuracy. + * + * Briefly put, we first assume there are no falsetickers, then + * scan the candidate list first from the low end upwards and + * then from the high end downwards. The scans stop when the + * number of intersections equals the number of candidates less + * the number of falsetickers. If this doesn't happen for a + * given number of falsetickers, we bump the number of + * falsetickers and try again. If the number of falsetickers + * becomes equal to or greater than half the number of + * candidates, the Albanians have won the Byzantine wars and + * correct synchronization is not possible. + * + * Here, nlist is the number of candidates and allow is the + * number of falsetickers. Upon exit, the truechimers are the + * survivors with offsets not less than low and not greater than + * high. There may be none of them. + */ + low = 1e9; + high = -1e9; + for (allow = 0; 2 * allow < nlist; allow++) { + + /* + * Bound the interval (low, high) as the smallest + * interval containing points from the most sources. + */ + n = 0; + for (i = 0; i < nl2; i++) { + low = endpoint[indx[i]].val; + n -= endpoint[indx[i]].type; + if (n >= nlist - allow) + break; + } + n = 0; + for (j = nl2 - 1; j >= 0; j--) { + high = endpoint[indx[j]].val; + n += endpoint[indx[j]].type; + if (n >= nlist - allow) + break; + } + + /* + * If an interval containing truechimers is found, stop. + * If not, increase the number of falsetickers and go + * around again. + */ + if (high > low) + break; + } + + /* + * Clustering algorithm. Whittle candidate list of falsetickers, + * who leave the island immediately. The TRUE peer is always a + * truechimer. We must leave at least one peer to collect the + * million bucks. + * + * We assert the correct time is contained in the interval, but + * the best offset estimate for the interval might not be + * contained in the interval. For this purpose, a truechimer is + * defined as the midpoint of an interval that overlaps the + * intersection interval. + */ + j = 0; + for (i = 0; i < nlist; i++) { + double h; + + peer = peers[i].peer; + h = peers[i].synch; + if ((high <= low || peer->offset + h < low || + peer->offset - h > high) && !(peer->flags & FLAG_TRUE)) + continue; + +#ifdef REFCLOCK + /* + * Eligible PPS peers must survive the intersection + * algorithm. Use the first one found, but don't + * include any of them in the cluster population. + */ + if (peer->flags & FLAG_PPS) { + if (typepps == NULL) + typepps = peer; + continue; + } +#endif /* REFCLOCK */ + + if (j != i) + peers[j] = peers[i]; + j++; + } + nlist = j; + + /* + * If no survivors remain at this point, check if the modem + * driver, local driver or orphan parent in that order. If so, + * nominate the first one found as the only survivor. + * Otherwise, give up and leave the island to the rats. + */ + if (nlist == 0) { + peers[0].error = 0; + peers[0].synch = sys_mindisp; +#ifdef REFCLOCK + if (typeacts != NULL) { + peers[0].peer = typeacts; + nlist = 1; + } else if (typelocal != NULL) { + peers[0].peer = typelocal; + nlist = 1; + } else +#endif /* REFCLOCK */ + if (typeorphan != NULL) { + peers[0].peer = typeorphan; + nlist = 1; + } + } + + /* + * Mark the candidates at this point as truechimers. + */ + for (i = 0; i < nlist; i++) { + peers[i].peer->new_status = CTL_PST_SEL_SELCAND; + DPRINTF(2, ("select: survivor %s %f\n", + stoa(&peers[i].peer->srcadr), peers[i].synch)); + } + + /* + * Now, vote outlyers off the island by select jitter weighted + * by root distance. Continue voting as long as there are more + * than sys_minclock survivors and the select jitter of the peer + * with the worst metric is greater than the minimum peer + * jitter. Stop if we are about to discard a TRUE or PREFER + * peer, who of course have the immunity idol. + */ + while (1) { + d = 1e9; + e = -1e9; + g = 0; + k = 0; + for (i = 0; i < nlist; i++) { + if (peers[i].error < d) + d = peers[i].error; + peers[i].seljit = 0; + if (nlist > 1) { + f = 0; + for (j = 0; j < nlist; j++) + f += DIFF(peers[j].peer->offset, + peers[i].peer->offset); + peers[i].seljit = SQRT(f / (nlist - 1)); + } + if (peers[i].seljit * peers[i].synch > e) { + g = peers[i].seljit; + e = peers[i].seljit * peers[i].synch; + k = i; + } + } + g = max(g, LOGTOD(sys_precision)); + if (nlist <= max(1, sys_minclock) || g <= d || + ((FLAG_TRUE | FLAG_PREFER) & peers[k].peer->flags)) + break; + + DPRINTF(3, ("select: drop %s seljit %.6f jit %.6f\n", + ntoa(&peers[k].peer->srcadr), g, d)); + if (nlist > sys_maxclock) + peers[k].peer->new_status = CTL_PST_SEL_EXCESS; + for (j = k + 1; j < nlist; j++) + peers[j - 1] = peers[j]; + nlist--; + } + + /* + * What remains is a list usually not greater than sys_minclock + * peers. Note that unsynchronized peers cannot survive this + * far. Count and mark these survivors. + * + * While at it, count the number of leap warning bits found. + * This will be used later to vote the system leap warning bit. + * If a leap warning bit is found on a reference clock, the vote + * is always won. + * + * Choose the system peer using a hybrid metric composed of the + * selection jitter scaled by the root distance augmented by + * stratum scaled by sys_mindisp (.001 by default). The goal of + * the small stratum factor is to avoid clockhop between a + * reference clock and a network peer which has a refclock and + * is using an older ntpd, which does not floor sys_rootdisp at + * sys_mindisp. + * + * In contrast, ntpd 4.2.6 and earlier used stratum primarily + * in selecting the system peer, using a weight of 1 second of + * additional root distance per stratum. This heavy bias is no + * longer appropriate, as the scaled root distance provides a + * more rational metric carrying the cumulative error budget. + */ + e = 1e9; + speer = 0; + leap_vote_ins = 0; + leap_vote_del = 0; + for (i = 0; i < nlist; i++) { + peer = peers[i].peer; + peer->unreach = 0; + peer->new_status = CTL_PST_SEL_SYNCCAND; + sys_survivors++; + if (peer->leap == LEAP_ADDSECOND) { + if (peer->flags & FLAG_REFCLOCK) + leap_vote_ins = nlist; + else if (leap_vote_ins < nlist) + leap_vote_ins++; + } + if (peer->leap == LEAP_DELSECOND) { + if (peer->flags & FLAG_REFCLOCK) + leap_vote_del = nlist; + else if (leap_vote_del < nlist) + leap_vote_del++; + } + if (peer->flags & FLAG_PREFER) + sys_prefer = peer; + speermet = peers[i].seljit * peers[i].synch + + peer->stratum * sys_mindisp; + if (speermet < e) { + e = speermet; + speer = i; + } + } + + /* + * Unless there are at least sys_misane survivors, leave the + * building dark. Otherwise, do a clockhop dance. Ordinarily, + * use the selected survivor speer. However, if the current + * system peer is not speer, stay with the current system peer + * as long as it doesn't get too old or too ugly. + */ + if (nlist > 0 && nlist >= sys_minsane) { + double x; + + typesystem = peers[speer].peer; + if (osys_peer == NULL || osys_peer == typesystem) { + sys_clockhop = 0; + } else if ((x = fabs(typesystem->offset - + osys_peer->offset)) < sys_mindisp) { + if (sys_clockhop == 0) + sys_clockhop = sys_mindisp; + else + sys_clockhop *= .5; + DPRINTF(1, ("select: clockhop %d %.6f %.6f\n", + j, x, sys_clockhop)); + if (fabs(x) < sys_clockhop) + typesystem = osys_peer; + else + sys_clockhop = 0; + } else { + sys_clockhop = 0; + } + } + + /* + * Mitigation rules of the game. We have the pick of the + * litter in typesystem if any survivors are left. If + * there is a prefer peer, use its offset and jitter. + * Otherwise, use the combined offset and jitter of all kitters. + */ + if (typesystem != NULL) { + if (sys_prefer == NULL) { + typesystem->new_status = CTL_PST_SEL_SYSPEER; + clock_combine(peers, sys_survivors, speer); + } else { + typesystem = sys_prefer; + sys_clockhop = 0; + typesystem->new_status = CTL_PST_SEL_SYSPEER; + sys_offset = typesystem->offset; + sys_jitter = typesystem->jitter; + } + DPRINTF(1, ("select: combine offset %.9f jitter %.9f\n", + sys_offset, sys_jitter)); + } +#ifdef REFCLOCK + /* + * If a PPS driver is lit and the combined offset is less than + * 0.4 s, select the driver as the PPS peer and use its offset + * and jitter. However, if this is the atom driver, use it only + * if there is a prefer peer or there are no survivors and none + * are required. + */ + if (typepps != NULL && fabs(sys_offset) < 0.4 && + (typepps->refclktype != REFCLK_ATOM_PPS || + (typepps->refclktype == REFCLK_ATOM_PPS && (sys_prefer != + NULL || (typesystem == NULL && sys_minsane == 0))))) { + typesystem = typepps; + sys_clockhop = 0; + typesystem->new_status = CTL_PST_SEL_PPS; + sys_offset = typesystem->offset; + sys_jitter = typesystem->jitter; + DPRINTF(1, ("select: pps offset %.9f jitter %.9f\n", + sys_offset, sys_jitter)); + } +#endif /* REFCLOCK */ + + /* + * If there are no survivors at this point, there is no + * system peer. If so and this is an old update, keep the + * current statistics, but do not update the clock. + */ + if (typesystem == NULL) { + if (osys_peer != NULL) { + if (sys_orphwait > 0) + orphwait = current_time + sys_orphwait; + report_event(EVNT_NOPEER, NULL, NULL); + } + sys_peer = NULL; + for (peer = peer_list; peer != NULL; peer = peer->p_link) + peer->status = peer->new_status; + return; + } + + /* + * Do not use old data, as this may mess up the clock discipline + * stability. + */ + if (typesystem->epoch <= sys_epoch) + return; + + /* + * We have found the alpha male. Wind the clock. + */ + if (osys_peer != typesystem) + report_event(PEVNT_NEWPEER, typesystem, NULL); + for (peer = peer_list; peer != NULL; peer = peer->p_link) + peer->status = peer->new_status; + clock_update(typesystem); +} + + +static void +clock_combine( + peer_select * peers, /* survivor list */ + int npeers, /* number of survivors */ + int syspeer /* index of sys.peer */ + ) +{ + int i; + double x, y, z, w; + + y = z = w = 0; + for (i = 0; i < npeers; i++) { + x = 1. / peers[i].synch; + y += x; + z += x * peers[i].peer->offset; + w += x * DIFF(peers[i].peer->offset, + peers[syspeer].peer->offset); + } + sys_offset = z / y; + sys_jitter = SQRT(w / y + SQUARE(peers[syspeer].seljit)); +} + + +/* + * root_distance - compute synchronization distance from peer to root + */ +static double +root_distance( + struct peer *peer /* peer structure pointer */ + ) +{ + double dtemp; + + /* + * Root Distance (LAMBDA) is defined as: + * (delta + DELTA)/2 + epsilon + EPSILON + phi + * + * where: + * delta is the round-trip delay + * DELTA is the root delay + * epsilon is the remote server precision + local precision + * + (15 usec each second) + * EPSILON is the root dispersion + * phi is the peer jitter statistic + * + * NB: Think hard about why we are using these values, and what + * the alternatives are, and the various pros/cons. + * + * DLM thinks these are probably the best choices from any of the + * other worse choices. + */ + dtemp = (peer->delay + peer->rootdelay) / 2 + + LOGTOD(peer->precision) + + LOGTOD(sys_precision) + + clock_phi * (current_time - peer->update) + + peer->rootdisp + + peer->jitter; + /* + * Careful squeak here. The value returned must be greater than + * the minimum root dispersion in order to avoid clockhop with + * highly precise reference clocks. Note that the root distance + * cannot exceed the sys_maxdist, as this is the cutoff by the + * selection algorithm. + */ + if (dtemp < sys_mindisp) + dtemp = sys_mindisp; + return (dtemp); +} + + +/* + * peer_xmit - send packet for persistent association. + */ +static void +peer_xmit( + struct peer *peer /* peer structure pointer */ + ) +{ + struct pkt xpkt; /* transmit packet */ + int sendlen, authlen; + keyid_t xkeyid = 0; /* transmit key ID */ + l_fp xmt_tx, xmt_ty; + + if (!peer->dstadr) /* drop peers without interface */ + return; + + xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, peer->version, + peer->hmode); + xpkt.stratum = STRATUM_TO_PKT(sys_stratum); + xpkt.ppoll = peer->hpoll; + xpkt.precision = sys_precision; + xpkt.refid = sys_refid; + xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); + xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); + HTONL_FP(&sys_reftime, &xpkt.reftime); + HTONL_FP(&peer->rec, &xpkt.org); + HTONL_FP(&peer->dst, &xpkt.rec); + + /* + * If the received packet contains a MAC, the transmitted packet + * is authenticated and contains a MAC. If not, the transmitted + * packet is not authenticated. + * + * It is most important when autokey is in use that the local + * interface IP address be known before the first packet is + * sent. Otherwise, it is not possible to compute a correct MAC + * the recipient will accept. Thus, the I/O semantics have to do + * a little more work. In particular, the wildcard interface + * might not be usable. + */ + sendlen = LEN_PKT_NOMAC; +#ifdef AUTOKEY + if (!(peer->flags & FLAG_SKEY) && peer->keyid == 0) { +#else /* !AUTOKEY follows */ + if (peer->keyid == 0) { +#endif /* !AUTOKEY */ + + /* + * Transmit a-priori timestamps + */ + get_systime(&xmt_tx); + if (peer->flip == 0) { /* basic mode */ + peer->aorg = xmt_tx; + HTONL_FP(&xmt_tx, &xpkt.xmt); + } else { /* interleaved modes */ + if (peer->hmode == MODE_BROADCAST) { /* bcst */ + HTONL_FP(&xmt_tx, &xpkt.xmt); + if (peer->flip > 0) + HTONL_FP(&peer->borg, + &xpkt.org); + else + HTONL_FP(&peer->aorg, + &xpkt.org); + } else { /* symmetric */ + if (peer->flip > 0) + HTONL_FP(&peer->borg, + &xpkt.xmt); + else + HTONL_FP(&peer->aorg, + &xpkt.xmt); + } + } + peer->t21_bytes = sendlen; + sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], + &xpkt, sendlen); + peer->sent++; + peer->throttle += (1 << peer->minpoll) - 2; + + /* + * Capture a-posteriori timestamps + */ + get_systime(&xmt_ty); + if (peer->flip != 0) { /* interleaved modes */ + if (peer->flip > 0) + peer->aorg = xmt_ty; + else + peer->borg = xmt_ty; + peer->flip = -peer->flip; + } + L_SUB(&xmt_ty, &xmt_tx); + LFPTOD(&xmt_ty, peer->xleave); +#ifdef DEBUG + if (debug) + printf("transmit: at %ld %s->%s mode %d len %d\n", + current_time, peer->dstadr ? + stoa(&peer->dstadr->sin) : "-", + stoa(&peer->srcadr), peer->hmode, sendlen); +#endif + return; + } + + /* + * Authentication is enabled, so the transmitted packet must be + * authenticated. If autokey is enabled, fuss with the various + * modes; otherwise, symmetric key cryptography is used. + */ +#ifdef AUTOKEY + if (peer->flags & FLAG_SKEY) { + struct exten *exten; /* extension field */ + + /* + * The Public Key Dance (PKD): Cryptographic credentials + * are contained in extension fields, each including a + * 4-octet length/code word followed by a 4-octet + * association ID and optional additional data. Optional + * data includes a 4-octet data length field followed by + * the data itself. Request messages are sent from a + * configured association; response messages can be sent + * from a configured association or can take the fast + * path without ever matching an association. Response + * messages have the same code as the request, but have + * a response bit and possibly an error bit set. In this + * implementation, a message may contain no more than + * one command and one or more responses. + * + * Cryptographic session keys include both a public and + * a private componet. Request and response messages + * using extension fields are always sent with the + * private component set to zero. Packets without + * extension fields indlude the private component when + * the session key is generated. + */ + while (1) { + + /* + * Allocate and initialize a keylist if not + * already done. Then, use the list in inverse + * order, discarding keys once used. Keep the + * latest key around until the next one, so + * clients can use client/server packets to + * compute propagation delay. + * + * Note that once a key is used from the list, + * it is retained in the key cache until the + * next key is used. This is to allow a client + * to retrieve the encrypted session key + * identifier to verify authenticity. + * + * If for some reason a key is no longer in the + * key cache, a birthday has happened or the key + * has expired, so the pseudo-random sequence is + * broken. In that case, purge the keylist and + * regenerate it. + */ + if (peer->keynumber == 0) + make_keylist(peer, peer->dstadr); + else + peer->keynumber--; + xkeyid = peer->keylist[peer->keynumber]; + if (authistrusted(xkeyid)) + break; + else + key_expire(peer); + } + peer->keyid = xkeyid; + exten = NULL; + switch (peer->hmode) { + + /* + * In broadcast server mode the autokey values are + * required by the broadcast clients. Push them when a + * new keylist is generated; otherwise, push the + * association message so the client can request them at + * other times. + */ + case MODE_BROADCAST: + if (peer->flags & FLAG_ASSOC) + exten = crypto_args(peer, CRYPTO_AUTO | + CRYPTO_RESP, peer->associd, NULL); + else + exten = crypto_args(peer, CRYPTO_ASSOC | + CRYPTO_RESP, peer->associd, NULL); + break; + + /* + * In symmetric modes the parameter, certificate, + * identity, cookie and autokey exchanges are + * required. The leapsecond exchange is optional. But, a + * peer will not believe the other peer until the other + * peer has synchronized, so the certificate exchange + * might loop until then. If a peer finds a broken + * autokey sequence, it uses the autokey exchange to + * retrieve the autokey values. In any case, if a new + * keylist is generated, the autokey values are pushed. + */ + case MODE_ACTIVE: + case MODE_PASSIVE: + + /* + * Parameter, certificate and identity. + */ + if (!peer->crypto) + exten = crypto_args(peer, CRYPTO_ASSOC, + peer->associd, hostval.ptr); + else if (!(peer->crypto & CRYPTO_FLAG_CERT)) + exten = crypto_args(peer, CRYPTO_CERT, + peer->associd, peer->issuer); + else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) + exten = crypto_args(peer, + crypto_ident(peer), peer->associd, + NULL); + + /* + * Cookie and autokey. We request the cookie + * only when the this peer and the other peer + * are synchronized. But, this peer needs the + * autokey values when the cookie is zero. Any + * time we regenerate the key list, we offer the + * autokey values without being asked. If for + * some reason either peer finds a broken + * autokey sequence, the autokey exchange is + * used to retrieve the autokey values. + */ + else if (sys_leap != LEAP_NOTINSYNC && + peer->leap != LEAP_NOTINSYNC && + !(peer->crypto & CRYPTO_FLAG_COOK)) + exten = crypto_args(peer, CRYPTO_COOK, + peer->associd, NULL); + else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) + exten = crypto_args(peer, CRYPTO_AUTO, + peer->associd, NULL); + else if (peer->flags & FLAG_ASSOC && + peer->crypto & CRYPTO_FLAG_SIGN) + exten = crypto_args(peer, CRYPTO_AUTO | + CRYPTO_RESP, peer->assoc, NULL); + + /* + * Wait for clock sync, then sign the + * certificate and retrieve the leapsecond + * values. + */ + else if (sys_leap == LEAP_NOTINSYNC) + break; + + else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) + exten = crypto_args(peer, CRYPTO_SIGN, + peer->associd, hostval.ptr); + else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) + exten = crypto_args(peer, CRYPTO_LEAP, + peer->associd, NULL); + break; + + /* + * In client mode the parameter, certificate, identity, + * cookie and sign exchanges are required. The + * leapsecond exchange is optional. If broadcast client + * mode the same exchanges are required, except that the + * autokey exchange is substitutes for the cookie + * exchange, since the cookie is always zero. If the + * broadcast client finds a broken autokey sequence, it + * uses the autokey exchange to retrieve the autokey + * values. + */ + case MODE_CLIENT: + + /* + * Parameter, certificate and identity. + */ + if (!peer->crypto) + exten = crypto_args(peer, CRYPTO_ASSOC, + peer->associd, hostval.ptr); + else if (!(peer->crypto & CRYPTO_FLAG_CERT)) + exten = crypto_args(peer, CRYPTO_CERT, + peer->associd, peer->issuer); + else if (!(peer->crypto & CRYPTO_FLAG_VRFY)) + exten = crypto_args(peer, + crypto_ident(peer), peer->associd, + NULL); + + /* + * Cookie and autokey. These are requests, but + * we use the peer association ID with autokey + * rather than our own. + */ + else if (!(peer->crypto & CRYPTO_FLAG_COOK)) + exten = crypto_args(peer, CRYPTO_COOK, + peer->associd, NULL); + else if (!(peer->crypto & CRYPTO_FLAG_AUTO)) + exten = crypto_args(peer, CRYPTO_AUTO, + peer->assoc, NULL); + + /* + * Wait for clock sync, then sign the + * certificate and retrieve the leapsecond + * values. + */ + else if (sys_leap == LEAP_NOTINSYNC) + break; + + else if (!(peer->crypto & CRYPTO_FLAG_SIGN)) + exten = crypto_args(peer, CRYPTO_SIGN, + peer->associd, hostval.ptr); + else if (!(peer->crypto & CRYPTO_FLAG_LEAP)) + exten = crypto_args(peer, CRYPTO_LEAP, + peer->associd, NULL); + break; + } + + /* + * Add a queued extension field if present. This is + * always a request message, so the reply ID is already + * in the message. If an error occurs, the error bit is + * lit in the response. + */ + if (peer->cmmd != NULL) { + u_int32 temp32; + + temp32 = CRYPTO_RESP; + peer->cmmd->opcode |= htonl(temp32); + sendlen += crypto_xmit(peer, &xpkt, NULL, + sendlen, peer->cmmd, 0); + free(peer->cmmd); + peer->cmmd = NULL; + } + + /* + * Add an extension field created above. All but the + * autokey response message are request messages. + */ + if (exten != NULL) { + if (exten->opcode != 0) + sendlen += crypto_xmit(peer, &xpkt, + NULL, sendlen, exten, 0); + free(exten); + } + + /* + * Calculate the next session key. Since extension + * fields are present, the cookie value is zero. + */ + if (sendlen > LEN_PKT_NOMAC) { + session_key(&peer->dstadr->sin, &peer->srcadr, + xkeyid, 0, 2); + } + } +#endif /* AUTOKEY */ + + /* + * Transmit a-priori timestamps + */ + get_systime(&xmt_tx); + if (peer->flip == 0) { /* basic mode */ + peer->aorg = xmt_tx; + HTONL_FP(&xmt_tx, &xpkt.xmt); + } else { /* interleaved modes */ + if (peer->hmode == MODE_BROADCAST) { /* bcst */ + HTONL_FP(&xmt_tx, &xpkt.xmt); + if (peer->flip > 0) + HTONL_FP(&peer->borg, &xpkt.org); + else + HTONL_FP(&peer->aorg, &xpkt.org); + } else { /* symmetric */ + if (peer->flip > 0) + HTONL_FP(&peer->borg, &xpkt.xmt); + else + HTONL_FP(&peer->aorg, &xpkt.xmt); + } + } + xkeyid = peer->keyid; + authlen = authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); + if (authlen == 0) { + report_event(PEVNT_AUTH, peer, "no key"); + peer->flash |= TEST5; /* auth error */ + peer->badauth++; + return; + } + sendlen += authlen; +#ifdef AUTOKEY + if (xkeyid > NTP_MAXKEY) + authtrust(xkeyid, 0); +#endif /* AUTOKEY */ + if (sendlen > sizeof(xpkt)) { + msyslog(LOG_ERR, "proto: buffer overflow %u", sendlen); + exit (-1); + } + peer->t21_bytes = sendlen; + sendpkt(&peer->srcadr, peer->dstadr, sys_ttl[peer->ttl], &xpkt, + sendlen); + peer->sent++; + peer->throttle += (1 << peer->minpoll) - 2; + + /* + * Capture a-posteriori timestamps + */ + get_systime(&xmt_ty); + if (peer->flip != 0) { /* interleaved modes */ + if (peer->flip > 0) + peer->aorg = xmt_ty; + else + peer->borg = xmt_ty; + peer->flip = -peer->flip; + } + L_SUB(&xmt_ty, &xmt_tx); + LFPTOD(&xmt_ty, peer->xleave); +#ifdef AUTOKEY +#ifdef DEBUG + if (debug) + printf("transmit: at %ld %s->%s mode %d keyid %08x len %d index %d\n", + current_time, latoa(peer->dstadr), + ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen, + peer->keynumber); +#endif +#else /* !AUTOKEY follows */ +#ifdef DEBUG + if (debug) + printf("transmit: at %ld %s->%s mode %d keyid %08x len %d\n", + current_time, peer->dstadr ? + ntoa(&peer->dstadr->sin) : "-", + ntoa(&peer->srcadr), peer->hmode, xkeyid, sendlen); +#endif +#endif /* !AUTOKEY */ +} + + +/* + * fast_xmit - Send packet for nonpersistent association. Note that + * neither the source or destination can be a broadcast address. + */ +static void +fast_xmit( + struct recvbuf *rbufp, /* receive packet pointer */ + int xmode, /* receive mode */ + keyid_t xkeyid, /* transmit key ID */ + int flags /* restrict mask */ + ) +{ + struct pkt xpkt; /* transmit packet structure */ + struct pkt *rpkt; /* receive packet structure */ + l_fp xmt_tx, xmt_ty; + int sendlen; +#ifdef AUTOKEY + u_int32 temp32; +#endif + + /* + * Initialize transmit packet header fields from the receive + * buffer provided. We leave the fields intact as received, but + * set the peer poll at the maximum of the receive peer poll and + * the system minimum poll (ntp_minpoll). This is for KoD rate + * control and not strictly specification compliant, but doesn't + * break anything. + * + * If the gazinta was from a multicast address, the gazoutta + * must go out another way. + */ + rpkt = &rbufp->recv_pkt; + if (rbufp->dstadr->flags & INT_MCASTOPEN) + rbufp->dstadr = findinterface(&rbufp->recv_srcadr); + + /* + * If this is a kiss-o'-death (KoD) packet, show leap + * unsynchronized, stratum zero, reference ID the four-character + * kiss code and system root delay. Note we don't reveal the + * local time, so these packets can't be used for + * synchronization. + */ + if (flags & RES_KOD) { + sys_kodsent++; + xpkt.li_vn_mode = PKT_LI_VN_MODE(LEAP_NOTINSYNC, + PKT_VERSION(rpkt->li_vn_mode), xmode); + xpkt.stratum = STRATUM_PKT_UNSPEC; + xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); + xpkt.precision = rpkt->precision; + memcpy(&xpkt.refid, "RATE", 4); + xpkt.rootdelay = rpkt->rootdelay; + xpkt.rootdisp = rpkt->rootdisp; + xpkt.reftime = rpkt->reftime; + xpkt.org = rpkt->xmt; + xpkt.rec = rpkt->xmt; + xpkt.xmt = rpkt->xmt; + + /* + * This is a normal packet. Use the system variables. + */ + } else { + xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, + PKT_VERSION(rpkt->li_vn_mode), xmode); + xpkt.stratum = STRATUM_TO_PKT(sys_stratum); + xpkt.ppoll = max(rpkt->ppoll, ntp_minpoll); + xpkt.precision = sys_precision; + xpkt.refid = sys_refid; + xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); + xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); + HTONL_FP(&sys_reftime, &xpkt.reftime); + xpkt.org = rpkt->xmt; + HTONL_FP(&rbufp->recv_time, &xpkt.rec); + get_systime(&xmt_tx); + HTONL_FP(&xmt_tx, &xpkt.xmt); + } + +#ifdef HAVE_NTP_SIGND + if (flags & RES_MSSNTP) { + send_via_ntp_signd(rbufp, xmode, xkeyid, flags, &xpkt); + return; + } +#endif /* HAVE_NTP_SIGND */ + + /* + * If the received packet contains a MAC, the transmitted packet + * is authenticated and contains a MAC. If not, the transmitted + * packet is not authenticated. + */ + sendlen = LEN_PKT_NOMAC; + if (rbufp->recv_length == sendlen) { + sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, + sendlen); +#ifdef DEBUG + if (debug) + printf( + "transmit: at %ld %s->%s mode %d len %d\n", + current_time, stoa(&rbufp->dstadr->sin), + stoa(&rbufp->recv_srcadr), xmode, sendlen); +#endif + return; + } + + /* + * The received packet contains a MAC, so the transmitted packet + * must be authenticated. For symmetric key cryptography, use + * the predefined and trusted symmetric keys to generate the + * cryptosum. For autokey cryptography, use the server private + * value to generate the cookie, which is unique for every + * source-destination-key ID combination. + */ +#ifdef AUTOKEY + if (xkeyid > NTP_MAXKEY) { + keyid_t cookie; + + /* + * The only way to get here is a reply to a legitimate + * client request message, so the mode must be + * MODE_SERVER. If an extension field is present, there + * can be only one and that must be a command. Do what + * needs, but with private value of zero so the poor + * jerk can decode it. If no extension field is present, + * use the cookie to generate the session key. + */ + cookie = session_key(&rbufp->recv_srcadr, + &rbufp->dstadr->sin, 0, sys_private, 0); + if (rbufp->recv_length > sendlen + (int)MAX_MAC_LEN) { + session_key(&rbufp->dstadr->sin, + &rbufp->recv_srcadr, xkeyid, 0, 2); + temp32 = CRYPTO_RESP; + rpkt->exten[0] |= htonl(temp32); + sendlen += crypto_xmit(NULL, &xpkt, rbufp, + sendlen, (struct exten *)rpkt->exten, + cookie); + } else { + session_key(&rbufp->dstadr->sin, + &rbufp->recv_srcadr, xkeyid, cookie, 2); + } + } +#endif /* AUTOKEY */ + get_systime(&xmt_tx); + sendlen += authencrypt(xkeyid, (u_int32 *)&xpkt, sendlen); +#ifdef AUTOKEY + if (xkeyid > NTP_MAXKEY) + authtrust(xkeyid, 0); +#endif /* AUTOKEY */ + sendpkt(&rbufp->recv_srcadr, rbufp->dstadr, 0, &xpkt, sendlen); + get_systime(&xmt_ty); + L_SUB(&xmt_ty, &xmt_tx); + sys_authdelay = xmt_ty; +#ifdef DEBUG + if (debug) + printf( + "transmit: at %ld %s->%s mode %d keyid %08x len %d\n", + current_time, ntoa(&rbufp->dstadr->sin), + ntoa(&rbufp->recv_srcadr), xmode, xkeyid, sendlen); +#endif +} + + +/* + * pool_xmit - resolve hostname or send unicast solicitation for pool. + */ +static void +pool_xmit( + struct peer *pool /* pool solicitor association */ + ) +{ +#ifdef WORKER + struct pkt xpkt; /* transmit packet structure */ + struct addrinfo hints; + int rc; + struct interface * lcladr; + sockaddr_u * rmtadr; + int restrict_mask; + struct peer * p; + l_fp xmt_tx; + + if (NULL == pool->ai) { + if (pool->addrs != NULL) { + /* free() is used with copy_addrinfo_list() */ + free(pool->addrs); + pool->addrs = NULL; + } + ZERO(hints); + hints.ai_family = AF(&pool->srcadr); + hints.ai_socktype = SOCK_DGRAM; + hints.ai_protocol = IPPROTO_UDP; + /* ignore getaddrinfo_sometime() errors, we will retry */ + rc = getaddrinfo_sometime( + pool->hostname, + "ntp", + &hints, + 0, /* no retry */ + &pool_name_resolved, + (void *)(u_int)pool->associd); + if (!rc) + DPRINTF(1, ("pool DNS lookup %s started\n", + pool->hostname)); + else + msyslog(LOG_ERR, + "unable to start pool DNS %s %m", + pool->hostname); + return; + } + + do { + /* copy_addrinfo_list ai_addr points to a sockaddr_u */ + rmtadr = (sockaddr_u *)(void *)pool->ai->ai_addr; + pool->ai = pool->ai->ai_next; + p = findexistingpeer(rmtadr, NULL, NULL, MODE_CLIENT, 0); + } while (p != NULL && pool->ai != NULL); + if (p != NULL) + return; /* out of addresses, re-query DNS next poll */ + restrict_mask = restrictions(rmtadr); + if (RES_FLAGS & restrict_mask) + restrict_source(rmtadr, 0, + current_time + POOL_SOLICIT_WINDOW + 1); + lcladr = findinterface(rmtadr); + memset(&xpkt, 0, sizeof(xpkt)); + xpkt.li_vn_mode = PKT_LI_VN_MODE(sys_leap, pool->version, + MODE_CLIENT); + xpkt.stratum = STRATUM_TO_PKT(sys_stratum); + xpkt.ppoll = pool->hpoll; + xpkt.precision = sys_precision; + xpkt.refid = sys_refid; + xpkt.rootdelay = HTONS_FP(DTOFP(sys_rootdelay)); + xpkt.rootdisp = HTONS_FP(DTOUFP(sys_rootdisp)); + HTONL_FP(&sys_reftime, &xpkt.reftime); + get_systime(&xmt_tx); + pool->aorg = xmt_tx; + HTONL_FP(&xmt_tx, &xpkt.xmt); + sendpkt(rmtadr, lcladr, sys_ttl[pool->ttl], &xpkt, + LEN_PKT_NOMAC); + pool->sent++; + pool->throttle += (1 << pool->minpoll) - 2; +#ifdef DEBUG + if (debug) + printf("transmit: at %ld %s->%s pool\n", + current_time, latoa(lcladr), stoa(rmtadr)); +#endif + msyslog(LOG_INFO, "Soliciting pool server %s", stoa(rmtadr)); +#endif /* WORKER */ +} + + +#ifdef AUTOKEY + /* + * group_test - test if this is the same group + * + * host assoc return action + * none none 0 mobilize * + * none group 0 mobilize * + * group none 0 mobilize * + * group group 1 mobilize + * group different 1 ignore + * * ignore if notrust + */ +int group_test( + char *grp, + char *ident + ) +{ + if (grp == NULL) + return (0); + + if (strcmp(grp, sys_groupname) == 0) + return (0); + + if (ident == NULL) + return (1); + + if (strcmp(grp, ident) == 0) + return (0); + + return (1); +} +#endif /* AUTOKEY */ + +#ifdef WORKER +void +pool_name_resolved( + int rescode, + int gai_errno, + void * context, + const char * name, + const char * service, + const struct addrinfo * hints, + const struct addrinfo * res + ) +{ + struct peer * pool; /* pool solicitor association */ + associd_t assoc; + + if (rescode) { + msyslog(LOG_ERR, + "error resolving pool %s: %s (%d)", + name, gai_strerror(rescode), rescode); + return; + } + + assoc = (associd_t)(u_int)context; + pool = findpeerbyassoc(assoc); + if (NULL == pool) { + msyslog(LOG_ERR, + "Could not find assoc %u for pool DNS %s", + assoc, name); + return; + } + DPRINTF(1, ("pool DNS %s completed\n", name)); + pool->addrs = copy_addrinfo_list(res); + pool->ai = pool->addrs; + pool_xmit(pool); + +} +#endif /* WORKER */ + + +#ifdef AUTOKEY +/* + * key_expire - purge the key list + */ +void +key_expire( + struct peer *peer /* peer structure pointer */ + ) +{ + int i; + + if (peer->keylist != NULL) { + for (i = 0; i <= peer->keynumber; i++) + authtrust(peer->keylist[i], 0); + free(peer->keylist); + peer->keylist = NULL; + } + value_free(&peer->sndval); + peer->keynumber = 0; + peer->flags &= ~FLAG_ASSOC; +#ifdef DEBUG + if (debug) + printf("key_expire: at %lu associd %d\n", current_time, + peer->associd); +#endif +} +#endif /* AUTOKEY */ + + +/* + * local_refid(peer) - check peer refid to avoid selecting peers + * currently synced to this ntpd. + */ +static int +local_refid( + struct peer * p + ) +{ + endpt * unicast_ep; + + if (p->dstadr != NULL && !(INT_MCASTIF & p->dstadr->flags)) + unicast_ep = p->dstadr; + else + unicast_ep = findinterface(&p->srcadr); + + if (unicast_ep != NULL && p->refid == unicast_ep->addr_refid) + return TRUE; + else + return FALSE; +} + + +/* + * Determine if the peer is unfit for synchronization + * + * A peer is unfit for synchronization if + * > TEST10 bad leap or stratum below floor or at or above ceiling + * > TEST11 root distance exceeded for remote peer + * > TEST12 a direct or indirect synchronization loop would form + * > TEST13 unreachable or noselect + */ +int /* FALSE if fit, TRUE if unfit */ +peer_unfit( + struct peer *peer /* peer structure pointer */ + ) +{ + int rval = 0; + + /* + * A stratum error occurs if (1) the server has never been + * synchronized, (2) the server stratum is below the floor or + * greater than or equal to the ceiling. + */ + if (peer->leap == LEAP_NOTINSYNC || peer->stratum < sys_floor || + peer->stratum >= sys_ceiling) + rval |= TEST10; /* bad synch or stratum */ + + /* + * A distance error for a remote peer occurs if the root + * distance is greater than or equal to the distance threshold + * plus the increment due to one host poll interval. + */ + if (!(peer->flags & FLAG_REFCLOCK) && root_distance(peer) >= + sys_maxdist + clock_phi * ULOGTOD(peer->hpoll)) + rval |= TEST11; /* distance exceeded */ + + /* + * A loop error occurs if the remote peer is synchronized to the + * local peer or if the remote peer is synchronized to the same + * server as the local peer but only if the remote peer is + * neither a reference clock nor an orphan. + */ + if (peer->stratum > 1 && local_refid(peer)) + rval |= TEST12; /* synchronization loop */ + + /* + * An unreachable error occurs if the server is unreachable or + * the noselect bit is set. + */ + if (!peer->reach || (peer->flags & FLAG_NOSELECT)) + rval |= TEST13; /* unreachable */ + + peer->flash &= ~PEER_TEST_MASK; + peer->flash |= rval; + return (rval); +} + + +/* + * Find the precision of this particular machine + */ +#define MINSTEP 20e-9 /* minimum clock increment (s) */ +#define MAXSTEP 1 /* maximum clock increment (s) */ +#define MINCHANGES 12 /* minimum number of step samples */ +#define MAXLOOPS ((int)(1. / MINSTEP)) /* avoid infinite loop */ + +/* + * This routine measures the system precision defined as the minimum of + * a sequence of differences between successive readings of the system + * clock. However, if a difference is less than MINSTEP, the clock has + * been read more than once during a clock tick and the difference is + * ignored. We set MINSTEP greater than zero in case something happens + * like a cache miss, and to tolerate underlying system clocks which + * ensure each reading is strictly greater than prior readings while + * using an underlying stepping (not interpolated) clock. + * + * sys_tick and sys_precision represent the time to read the clock for + * systems with high-precision clocks, and the tick interval or step + * size for lower-precision stepping clocks. + * + * This routine also measures the time to read the clock on stepping + * system clocks by counting the number of readings between changes of + * the underlying clock. With either type of clock, the minimum time + * to read the clock is saved as sys_fuzz, and used to ensure the + * get_systime() readings always increase and are fuzzed below sys_fuzz. + */ +void +measure_precision(void) +{ + /* + * With sys_fuzz set to zero, get_systime() fuzzing of low bits + * is effectively disabled. trunc_os_clock is FALSE to disable + * get_ostime() simulation of a low-precision system clock. + */ + set_sys_fuzz(0.); + trunc_os_clock = FALSE; + measured_tick = measure_tick_fuzz(); + set_sys_tick_precision(measured_tick); + msyslog(LOG_INFO, "proto: precision = %.3f usec (%d)", + sys_tick * 1e6, sys_precision); + if (sys_fuzz < sys_tick) { + msyslog(LOG_NOTICE, "proto: fuzz beneath %.3f usec", + sys_fuzz * 1e6); + } +} + + +/* + * measure_tick_fuzz() + * + * measures the minimum time to read the clock (stored in sys_fuzz) + * and returns the tick, the larger of the minimum increment observed + * between successive clock readings and the time to read the clock. + */ +double +measure_tick_fuzz(void) +{ + l_fp minstep; /* MINSTEP as l_fp */ + l_fp val; /* current seconds fraction */ + l_fp last; /* last seconds fraction */ + l_fp ldiff; /* val - last */ + double tick; /* computed tick value */ + double diff; + long repeats; + long max_repeats; + int changes; + int i; /* log2 precision */ + + tick = MAXSTEP; + max_repeats = 0; + repeats = 0; + changes = 0; + DTOLFP(MINSTEP, &minstep); + get_systime(&last); + for (i = 0; i < MAXLOOPS && changes < MINCHANGES; i++) { + get_systime(&val); + ldiff = val; + L_SUB(&ldiff, &last); + last = val; + if (L_ISGT(&ldiff, &minstep)) { + max_repeats = max(repeats, max_repeats); + repeats = 0; + changes++; + LFPTOD(&ldiff, diff); + tick = min(diff, tick); + } else { + repeats++; + } + } + if (changes < MINCHANGES) { + msyslog(LOG_ERR, "Fatal error: precision could not be measured (MINSTEP too large?)"); + exit(1); + } + + if (0 == max_repeats) { + set_sys_fuzz(tick); + } else { + set_sys_fuzz(tick / max_repeats); + } + + return tick; +} + + +void +set_sys_tick_precision( + double tick + ) +{ + int i; + + if (tick > 1.) { + msyslog(LOG_ERR, + "unsupported tick %.3f > 1s ignored", tick); + return; + } + if (tick < measured_tick) { + msyslog(LOG_ERR, + "proto: tick %.3f less than measured tick %.3f, ignored", + tick, measured_tick); + return; + } else if (tick > measured_tick) { + trunc_os_clock = TRUE; + msyslog(LOG_NOTICE, + "proto: truncating system clock to multiples of %.9f", + tick); + } + sys_tick = tick; + + /* + * Find the nearest power of two. + */ + for (i = 0; tick <= 1; i--) + tick *= 2; + if (tick - 1 > 1 - tick / 2) + i++; + + sys_precision = (s_char)i; +} + + +/* + * init_proto - initialize the protocol module's data + */ +void +init_proto(void) +{ + l_fp dummy; + int i; + + /* + * Fill in the sys_* stuff. Default is don't listen to + * broadcasting, require authentication. + */ + sys_leap = LEAP_NOTINSYNC; + sys_stratum = STRATUM_UNSPEC; + memcpy(&sys_refid, "INIT", 4); + sys_peer = NULL; + sys_rootdelay = 0; + sys_rootdisp = 0; + L_CLR(&sys_reftime); + sys_jitter = 0; + measure_precision(); + get_systime(&dummy); + sys_survivors = 0; + sys_manycastserver = 0; + sys_bclient = 0; + sys_bdelay = 0; + sys_authenticate = 1; + sys_stattime = current_time; + orphwait = current_time + sys_orphwait; + proto_clr_stats(); + for (i = 0; i < MAX_TTL; i++) { + sys_ttl[i] = (u_char)((i * 256) / MAX_TTL); + sys_ttlmax = i; + } + hardpps_enable = 0; + stats_control = 1; +} + + +/* + * proto_config - configure the protocol module + */ +void +proto_config( + int item, + u_long value, + double dvalue, + sockaddr_u *svalue + ) +{ + /* + * Figure out what he wants to change, then do it + */ + DPRINTF(2, ("proto_config: code %d value %lu dvalue %lf\n", + item, value, dvalue)); + + switch (item) { + + /* + * enable and disable commands - arguments are Boolean. + */ + case PROTO_AUTHENTICATE: /* authentication (auth) */ + sys_authenticate = value; + break; + + case PROTO_BROADCLIENT: /* broadcast client (bclient) */ + sys_bclient = (int)value; + if (sys_bclient == 0) + io_unsetbclient(); + else + io_setbclient(); + break; + +#ifdef REFCLOCK + case PROTO_CAL: /* refclock calibrate (calibrate) */ + cal_enable = value; + break; +#endif /* REFCLOCK */ + + case PROTO_KERNEL: /* kernel discipline (kernel) */ + select_loop(value); + break; + + case PROTO_MONITOR: /* monitoring (monitor) */ + if (value) + mon_start(MON_ON); + else + mon_stop(MON_ON); + break; + + case PROTO_NTP: /* NTP discipline (ntp) */ + ntp_enable = value; + break; + + case PROTO_MODE7: /* mode7 management (ntpdc) */ + ntp_mode7 = value; + break; + + case PROTO_PPS: /* PPS discipline (pps) */ + hardpps_enable = value; + break; + + case PROTO_FILEGEN: /* statistics (stats) */ + stats_control = value; + break; + + /* + * tos command - arguments are double, sometimes cast to int + */ + case PROTO_BEACON: /* manycast beacon (beacon) */ + sys_beacon = (int)dvalue; + break; + + case PROTO_BROADDELAY: /* default broadcast delay (bdelay) */ + sys_bdelay = dvalue; + break; + + case PROTO_CEILING: /* stratum ceiling (ceiling) */ + sys_ceiling = (int)dvalue; + break; + + case PROTO_COHORT: /* cohort switch (cohort) */ + sys_cohort = (int)dvalue; + break; + + case PROTO_FLOOR: /* stratum floor (floor) */ + sys_floor = (int)dvalue; + break; + + case PROTO_MAXCLOCK: /* maximum candidates (maxclock) */ + sys_maxclock = (int)dvalue; + break; + + case PROTO_MAXDIST: /* select threshold (maxdist) */ + sys_maxdist = dvalue; + break; + + case PROTO_CALLDELAY: /* modem call delay (mdelay) */ + break; /* NOT USED */ + + case PROTO_MINCLOCK: /* minimum candidates (minclock) */ + sys_minclock = (int)dvalue; + break; + + case PROTO_MINDISP: /* minimum distance (mindist) */ + sys_mindisp = dvalue; + break; + + case PROTO_MINSANE: /* minimum survivors (minsane) */ + sys_minsane = (int)dvalue; + break; + + case PROTO_ORPHAN: /* orphan stratum (orphan) */ + sys_orphan = (int)dvalue; + break; + + case PROTO_ORPHWAIT: /* orphan wait (orphwait) */ + orphwait -= sys_orphwait; + sys_orphwait = (int)dvalue; + orphwait += sys_orphwait; + break; + + /* + * Miscellaneous commands + */ + case PROTO_MULTICAST_ADD: /* add group address */ + if (svalue != NULL) + io_multicast_add(svalue); + sys_bclient = 1; + break; + + case PROTO_MULTICAST_DEL: /* delete group address */ + if (svalue != NULL) + io_multicast_del(svalue); + break; + + default: + msyslog(LOG_NOTICE, + "proto: unsupported option %d", item); + } +} + + +/* + * proto_clr_stats - clear protocol stat counters + */ +void +proto_clr_stats(void) +{ + sys_stattime = current_time; + sys_received = 0; + sys_processed = 0; + sys_newversion = 0; + sys_oldversion = 0; + sys_declined = 0; + sys_restricted = 0; + sys_badlength = 0; + sys_badauth = 0; + sys_limitrejected = 0; + sys_kodsent = 0; +} |