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authorAdam Tkac <vonsch@gmail.com>2009-11-22 02:43:55 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2009-11-22 02:43:55 (GMT)
commitb1585064fdac138b3bd14c2b64f64c67ec08b654 (patch)
treeb632b12a9aea4953751bb1569bf9290db42c5c4d
parentd095fd4d95fd6241847f01e4fd674bc177310c33 (diff)
downloadbusybox-b1585064fdac138b3bd14c2b64f64c67ec08b654.tar.gz
busybox-b1585064fdac138b3bd14c2b64f64c67ec08b654.tar.bz2
ntpd: new applet by Adam Tkac. +5k.
Signed-off-by: Adam Tkac <vonsch@gmail.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--include/applets.h1
-rw-r--r--include/usage.h11
-rw-r--r--networking/Config.in14
-rw-r--r--networking/Kbuild1
-rw-r--r--networking/ntpd.c999
5 files changed, 1026 insertions, 0 deletions
diff --git a/include/applets.h b/include/applets.h
index 15ccf9c..a2d1e95 100644
--- a/include/applets.h
+++ b/include/applets.h
@@ -285,6 +285,7 @@ IF_NICE(APPLET(nice, _BB_DIR_BIN, _BB_SUID_DROP))
IF_NMETER(APPLET(nmeter, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_NOHUP(APPLET(nohup, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_NSLOOKUP(APPLET(nslookup, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+IF_NTPD(APPLET(ntpd, _BB_DIR_USR_SBIN, _BB_SUID_DROP))
IF_OD(APPLET(od, _BB_DIR_USR_BIN, _BB_SUID_DROP))
IF_OPENVT(APPLET(openvt, _BB_DIR_USR_BIN, _BB_SUID_DROP))
//IF_PARSE(APPLET(parse, _BB_DIR_USR_BIN, _BB_SUID_DROP))
diff --git a/include/usage.h b/include/usage.h
index eae9650..3ccf160 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -3210,6 +3210,17 @@
"Name: debian\n" \
"Address: 127.0.0.1\n"
+#define ntpd_trivial_usage \
+ "[-dngl] [-p PEER]..."
+#define ntpd_full_usage "\n\n" \
+ "NTP client/server\n" \
+ "\nOptions:" \
+ "\n -d Verbose" \
+ "\n -n Do not daemonize" \
+ "\n -g Set system time even if offset is > 1000 sec" \
+ "\n -l Run as server on port 123" \
+ "\n -p PEER Obtain time from PEER (may be repeated)" \
+
#define od_trivial_usage \
"[-aBbcDdeFfHhIiLlOovXx] " IF_DESKTOP("[-t TYPE] ") "[FILE]"
#define od_full_usage "\n\n" \
diff --git a/networking/Config.in b/networking/Config.in
index 5f1b6f6..3d29622 100644
--- a/networking/Config.in
+++ b/networking/Config.in
@@ -661,6 +661,20 @@ config NSLOOKUP
help
nslookup is a tool to query Internet name servers.
+config NTPD
+ bool "ntpd"
+ default n
+ help
+ The NTP client/server daemon.
+
+config FEATURE_NTPD_SERVER
+ bool "Make ntpd usable as a NTP server"
+ default y
+ depends on NTPD
+ help
+ Make ntpd usable as a NTP server. If you disable this option
+ ntpd will be usable only as a NTP client.
+
config PING
bool "ping"
default n
diff --git a/networking/Kbuild b/networking/Kbuild
index 866d42f..b0765bc 100644
--- a/networking/Kbuild
+++ b/networking/Kbuild
@@ -27,6 +27,7 @@ lib-$(CONFIG_NAMEIF) += nameif.o
lib-$(CONFIG_NC) += nc.o
lib-$(CONFIG_NETSTAT) += netstat.o
lib-$(CONFIG_NSLOOKUP) += nslookup.o
+lib-$(CONFIG_NTPD) += ntpd.o
lib-$(CONFIG_PING) += ping.o
lib-$(CONFIG_PING6) += ping.o
lib-$(CONFIG_PSCAN) += pscan.o
diff --git a/networking/ntpd.c b/networking/ntpd.c
new file mode 100644
index 0000000..62a00a5
--- /dev/null
+++ b/networking/ntpd.c
@@ -0,0 +1,999 @@
+/*
+ * NTP client/server, based on OpenNTPD 3.9p1
+ *
+ * Author: Adam Tkac <vonsch@gmail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+
+#include "libbb.h"
+#include <netinet/ip.h> /* For IPTOS_LOWDELAY definition */
+
+#ifndef IP_PKTINFO
+# error "Sorry, your kernel has to support IP_PKTINFO"
+#endif
+
+#define INTERVAL_QUERY_NORMAL 30 /* sync to peers every n secs */
+#define INTERVAL_QUERY_PATHETIC 60
+#define INTERVAL_QUERY_AGRESSIVE 5
+
+#define TRUSTLEVEL_BADPEER 6
+#define TRUSTLEVEL_PATHETIC 2
+#define TRUSTLEVEL_AGRESSIVE 8
+#define TRUSTLEVEL_MAX 10
+
+#define QSCALE_OFF_MIN 0.05
+#define QSCALE_OFF_MAX 0.50
+
+#define QUERYTIME_MAX 15 /* single query might take n secs max */
+#define OFFSET_ARRAY_SIZE 8
+#define SETTIME_MIN_OFFSET 180 /* min offset for settime at start */
+#define SETTIME_TIMEOUT 15 /* max seconds to wait with -s */
+
+/* Style borrowed from NTP ref/tcpdump and updated for SNTPv4 (RFC2030). */
+
+/*
+ * RFC Section 3
+ *
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Integer Part |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Fraction Part |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * 0 1 2 3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Integer Part | Fraction Part |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+*/
+typedef struct {
+ uint32_t int_partl;
+ uint32_t fractionl;
+} l_fixedpt_t;
+
+typedef struct {
+ uint16_t int_parts;
+ uint16_t fractions;
+} s_fixedpt_t;
+
+#define NTP_DIGESTSIZE 16
+#define NTP_MSGSIZE_NOAUTH 48
+#define NTP_MSGSIZE (NTP_MSGSIZE_NOAUTH + 4 + NTP_DIGESTSIZE)
+
+typedef struct {
+ uint8_t status; /* status of local clock and leap info */
+ uint8_t stratum; /* Stratum level */
+ uint8_t ppoll; /* poll value */
+ int8_t precision;
+ s_fixedpt_t rootdelay;
+ s_fixedpt_t dispersion;
+ uint32_t refid;
+ l_fixedpt_t reftime;
+ l_fixedpt_t orgtime;
+ l_fixedpt_t rectime;
+ l_fixedpt_t xmttime;
+ uint32_t keyid;
+ uint8_t digest[NTP_DIGESTSIZE];
+} ntp_msg_t;
+
+typedef struct {
+ int fd;
+ ntp_msg_t msg;
+ double xmttime;
+} ntp_query_t;
+
+enum {
+ NTP_VERSION = 4,
+ NTP_MAXSTRATUM = 15,
+ /* Leap Second Codes (high order two bits) */
+ LI_NOWARNING = (0 << 6), /* no warning */
+ LI_PLUSSEC = (1 << 6), /* add a second (61 seconds) */
+ LI_MINUSSEC = (2 << 6), /* minus a second (59 seconds) */
+ LI_ALARM = (3 << 6), /* alarm condition */
+
+ /* Status Masks */
+ MODE_MASK = (7 << 0),
+ VERSION_MASK = (7 << 3),
+ LI_MASK = (3 << 6),
+
+ /* Mode values */
+ MODE_RES0 = 0, /* reserved */
+ MODE_SYM_ACT = 1, /* symmetric active */
+ MODE_SYM_PAS = 2, /* symmetric passive */
+ MODE_CLIENT = 3, /* client */
+ MODE_SERVER = 4, /* server */
+ MODE_BROADCAST = 5, /* broadcast */
+ MODE_RES1 = 6, /* reserved for NTP control message */
+ MODE_RES2 = 7 /* reserved for private use */
+};
+
+#define JAN_1970 2208988800UL /* 1970 - 1900 in seconds */
+
+enum client_state {
+ STATE_NONE,
+ STATE_QUERY_SENT,
+ STATE_REPLY_RECEIVED
+};
+
+typedef struct {
+ double rootdelay;
+ double rootdispersion;
+ double reftime;
+ uint32_t refid;
+ uint32_t refid4;
+ uint8_t synced;
+ uint8_t leap;
+ int8_t precision;
+ uint8_t poll;
+ uint8_t stratum;
+} ntp_status_t;
+
+typedef struct {
+ ntp_status_t status;
+ double offset;
+ double delay;
+ double error;
+ time_t rcvd;
+ uint8_t good;
+} ntp_offset_t;
+
+typedef struct {
+ len_and_sockaddr *lsa;
+ ntp_query_t query;
+ ntp_offset_t reply[OFFSET_ARRAY_SIZE];
+ ntp_offset_t update;
+ enum client_state state;
+ time_t next;
+ time_t deadline;
+ uint8_t shift;
+ uint8_t trustlevel;
+} ntp_peer_t;
+
+
+struct globals {
+ unsigned verbose;
+#if ENABLE_FEATURE_NTPD_SERVER
+ int listen_fd;
+#endif
+ llist_t *ntp_peers;
+ ntp_status_t status;
+ uint32_t scale;
+ uint8_t settime;
+ uint8_t firstadj;
+ smallint peer_cnt;
+
+};
+#define G (*ptr_to_globals)
+
+
+static const int const_IPTOS_LOWDELAY = IPTOS_LOWDELAY;
+
+
+static void
+set_next(ntp_peer_t *p, time_t t)
+{
+ p->next = time(NULL) + t;
+ p->deadline = 0;
+}
+
+static void
+add_peers(const char *s)
+{
+ ntp_peer_t *p;
+
+ p = xzalloc(sizeof(*p));
+//TODO: big ntpd uses all IPs, not just 1st, do we need to mimic that?
+ p->lsa = xhost2sockaddr(s, 123);
+ p->query.fd = -1;
+ p->query.msg.status = MODE_CLIENT | (NTP_VERSION << 3);
+ if (STATE_NONE != 0)
+ p->state = STATE_NONE;
+ p->trustlevel = TRUSTLEVEL_PATHETIC;
+ p->query.fd = -1;
+ set_next(p, 0);
+
+ llist_add_to(&G.ntp_peers, p);
+ G.peer_cnt++;
+}
+
+static double
+gettime(void)
+{
+ struct timeval tv;
+
+ gettimeofday(&tv, NULL); /* never fails */
+ return (tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec);
+}
+
+
+static void
+d_to_tv(double d, struct timeval *tv)
+{
+ tv->tv_sec = (long)d;
+ tv->tv_usec = (d - tv->tv_sec) * 1000000;
+}
+
+static double
+lfp_to_d(l_fixedpt_t lfp)
+{
+ double ret;
+
+ lfp.int_partl = ntohl(lfp.int_partl);
+ lfp.fractionl = ntohl(lfp.fractionl);
+ ret = (double)(lfp.int_partl) + ((double)lfp.fractionl / UINT_MAX);
+ return ret;
+}
+
+#if ENABLE_FEATURE_NTPD_SERVER
+static l_fixedpt_t
+d_to_lfp(double d)
+{
+ l_fixedpt_t lfp;
+
+ lfp.int_partl = htonl((uint32_t)d);
+ lfp.fractionl = htonl((uint32_t)((d - (u_int32_t)d) * UINT_MAX));
+ return lfp;
+}
+#endif
+
+static double
+sfp_to_d(s_fixedpt_t sfp)
+{
+ double ret;
+
+ sfp.int_parts = ntohs(sfp.int_parts);
+ sfp.fractions = ntohs(sfp.fractions);
+ ret = (double)(sfp.int_parts) + ((double)sfp.fractions / USHRT_MAX);
+ return ret;
+}
+
+#if ENABLE_FEATURE_NTPD_SERVER
+static s_fixedpt_t
+d_to_sfp(double d)
+{
+ s_fixedpt_t sfp;
+
+ sfp.int_parts = htons((uint16_t)d);
+ sfp.fractions = htons((uint16_t)((d - (u_int16_t)d) * USHRT_MAX));
+ return sfp;
+}
+#endif
+
+static void
+set_deadline(ntp_peer_t *p, time_t t)
+{
+ p->deadline = time(NULL) + t;
+ p->next = 0;
+}
+
+static time_t
+error_interval(void)
+{
+ time_t interval, r;
+
+ interval = INTERVAL_QUERY_PATHETIC * QSCALE_OFF_MAX / QSCALE_OFF_MIN;
+ r = random() % (interval / 10);
+ return (interval + r);
+}
+
+static int
+sendmsg_wrap(int fd,
+ const struct sockaddr *from, const struct sockaddr *to, socklen_t addrlen,
+ ntp_msg_t *msg, ssize_t len)
+{
+ ssize_t ret;
+
+ errno = 0;
+ if (!from) {
+ ret = sendto(fd, msg, len, 0, to, addrlen);
+ } else {
+ ret = send_to_from(fd, msg, len, 0, to, from, addrlen);
+ }
+ if (ret != len) {
+ bb_perror_msg("send failed");
+ return -1;
+ }
+ return 0;
+}
+
+static int
+client_query(ntp_peer_t *p)
+{
+ if (p->query.fd == -1) {
+ p->query.fd = xsocket(p->lsa->u.sa.sa_family, SOCK_DGRAM, 0);
+#if ENABLE_FEATURE_IPV6
+ if (p->lsa->u.sa.sa_family == AF_INET)
+#endif
+ setsockopt(p->query.fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
+ }
+
+ /*
+ * Send out a random 64-bit number as our transmit time. The NTP
+ * server will copy said number into the originate field on the
+ * response that it sends us. This is totally legal per the SNTP spec.
+ *
+ * The impact of this is two fold: we no longer send out the current
+ * system time for the world to see (which may aid an attacker), and
+ * it gives us a (not very secure) way of knowing that we're not
+ * getting spoofed by an attacker that can't capture our traffic
+ * but can spoof packets from the NTP server we're communicating with.
+ *
+ * Save the real transmit timestamp locally.
+ */
+
+ p->query.msg.xmttime.int_partl = random();
+ p->query.msg.xmttime.fractionl = random();
+ p->query.xmttime = gettime();
+
+ if (sendmsg_wrap(p->query.fd, /*from:*/ NULL, /*to:*/ &p->lsa->u.sa, /*addrlen:*/ p->lsa->len,
+ &p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) {
+ set_next(p, INTERVAL_QUERY_PATHETIC);
+ return -1;
+ }
+
+ p->state = STATE_QUERY_SENT;
+ set_deadline(p, QUERYTIME_MAX);
+
+ return 0;
+}
+
+static int
+offset_compare(const void *aa, const void *bb)
+{
+ const ntp_peer_t * const *a;
+ const ntp_peer_t * const *b;
+
+ a = aa;
+ b = bb;
+
+ if ((*a)->update.offset < (*b)->update.offset)
+ return -1;
+ return ((*a)->update.offset > (*b)->update.offset);
+}
+
+static uint32_t
+updated_scale(double offset)
+{
+ if (offset < 0)
+ offset = -offset;
+
+ if (offset > QSCALE_OFF_MAX)
+ return 1;
+ if (offset < QSCALE_OFF_MIN)
+ return QSCALE_OFF_MAX / QSCALE_OFF_MIN;
+ return QSCALE_OFF_MAX / offset;
+}
+
+static void
+adjtime_wrap(void)
+{
+ ntp_peer_t *p;
+ unsigned offset_cnt;
+ int i = 0;
+ ntp_peer_t **peers;
+ double offset_median;
+ llist_t *item;
+ len_and_sockaddr *lsa;
+ struct timeval tv, olddelta;
+
+ offset_cnt = 0;
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ p = (ntp_peer_t *) item->data;
+ if (p->trustlevel < TRUSTLEVEL_BADPEER)
+ continue;
+ if (!p->update.good)
+ return;
+ offset_cnt++;
+ }
+
+ peers = xzalloc(sizeof(ntp_peer_t *) * offset_cnt);
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ p = (ntp_peer_t *) item->data;
+ if (p->trustlevel < TRUSTLEVEL_BADPEER)
+ continue;
+ peers[i++] = p;
+ }
+
+ qsort(peers, offset_cnt, sizeof(ntp_peer_t *), offset_compare);
+
+ if (offset_cnt != 0) {
+ if ((offset_cnt & 1) == 0) {
+//TODO: try offset_cnt /= 2...
+ offset_median =
+ (peers[offset_cnt / 2 - 1]->update.offset +
+ peers[offset_cnt / 2]->update.offset) / 2;
+ G.status.rootdelay =
+ (peers[offset_cnt / 2 - 1]->update.delay +
+ peers[offset_cnt / 2]->update.delay) / 2;
+ G.status.stratum = MAX(
+ peers[offset_cnt / 2 - 1]->update.status.stratum,
+ peers[offset_cnt / 2]->update.status.stratum);
+ } else {
+ offset_median = peers[offset_cnt / 2]->update.offset;
+ G.status.rootdelay = peers[offset_cnt / 2]->update.delay;
+ G.status.stratum = peers[offset_cnt / 2]->update.status.stratum;
+ }
+ G.status.leap = peers[offset_cnt / 2]->update.status.leap;
+
+ bb_info_msg("adjusting local clock by %fs", offset_median);
+
+ d_to_tv(offset_median, &tv);
+ if (adjtime(&tv, &olddelta) == -1)
+ bb_error_msg("adjtime failed");
+ else if (!G.firstadj
+ && olddelta.tv_sec == 0
+ && olddelta.tv_usec == 0
+ && !G.status.synced
+ ) {
+ bb_info_msg("clock synced");
+ G.status.synced = 1;
+ } else if (G.status.synced) {
+ bb_info_msg("clock unsynced");
+ G.status.synced = 0;
+ }
+
+ G.firstadj = 0;
+ G.status.reftime = gettime();
+ G.status.stratum++; /* one more than selected peer */
+ G.scale = updated_scale(offset_median);
+
+ G.status.refid4 = peers[offset_cnt / 2]->update.status.refid4;
+
+ lsa = peers[offset_cnt / 2]->lsa;
+ G.status.refid =
+#if ENABLE_FEATURE_IPV6
+ lsa->u.sa.sa_family != AF_INET ?
+ G.status.refid4 :
+#endif
+ lsa->u.sin.sin_addr.s_addr;
+ }
+
+ free(peers);
+
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ p = (ntp_peer_t *) item->data;
+ p->update.good = 0;
+ }
+}
+
+static void
+settime(double offset)
+{
+ ntp_peer_t *p;
+ llist_t *item;
+ struct timeval tv, curtime;
+ char buf[80];
+ time_t tval;
+
+#if 0
+ if (!G.settime)
+ return;
+#endif
+
+ /* if the offset is small, don't call settimeofday */
+ if (offset < SETTIME_MIN_OFFSET && offset > -SETTIME_MIN_OFFSET)
+ return;
+
+ gettimeofday(&curtime, NULL); /* never fails */
+
+ d_to_tv(offset, &tv);
+ curtime.tv_usec += tv.tv_usec + 1000000;
+ curtime.tv_sec += tv.tv_sec - 1 + (curtime.tv_usec / 1000000);
+ curtime.tv_usec %= 1000000;
+
+ if (settimeofday(&curtime, NULL) == -1) {
+ bb_error_msg("settimeofday");
+ return;
+ }
+
+ G.settime = 0;
+
+ tval = curtime.tv_sec;
+ strftime(buf, sizeof(buf), "%a %b %e %H:%M:%S %Z %Y", localtime(&tval));
+
+ /* Do we want to print message below to system log when daemonized? */
+ bb_info_msg("set local clock to %s (offset %fs)", buf, offset);
+
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ p = (ntp_peer_t *) item->data;
+ if (p->next)
+ p->next -= offset;
+ if (p->deadline)
+ p->deadline -= offset;
+ }
+}
+
+static void
+client_update(ntp_peer_t *p)
+{
+ int i, best = 0, good = 0;
+
+ /*
+ * clock filter
+ * find the offset which arrived with the lowest delay
+ * use that as the peer update
+ * invalidate it and all older ones
+ */
+
+ for (i = 0; good == 0 && i < OFFSET_ARRAY_SIZE; i++) {
+ if (p->reply[i].good) {
+ good++;
+ best = i;
+ }
+ }
+
+ for (; i < OFFSET_ARRAY_SIZE; i++) {
+ if (p->reply[i].good) {
+ good++;
+ if (p->reply[i].delay < p->reply[best].delay)
+ best = i;
+ }
+ }
+
+ if (good < 8)
+ return;
+
+ memcpy(&p->update, &p->reply[best], sizeof(p->update));
+ adjtime_wrap();
+
+ for (i = 0; i < OFFSET_ARRAY_SIZE; i++)
+ if (p->reply[i].rcvd <= p->reply[best].rcvd)
+ p->reply[i].good = 0;
+}
+
+static time_t
+scale_interval(time_t requested)
+{
+ time_t interval, r;
+
+ interval = requested * G.scale;
+ r = random() % MAX(5, interval / 10);
+ return (interval + r);
+}
+
+static void
+client_dispatch(ntp_peer_t *p)
+{
+ char *addr;
+ ssize_t size;
+ ntp_msg_t msg;
+ double T1, T2, T3, T4;
+ time_t interval;
+ ntp_offset_t *offset;
+
+ addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
+
+ size = recvfrom(p->query.fd, &msg, sizeof(msg), 0, NULL, NULL);
+ if (size == -1) {
+ bb_perror_msg("recvfrom(%s) error", addr);
+ if (errno == EHOSTUNREACH || errno == EHOSTDOWN
+ || errno == ENETUNREACH || errno == ENETDOWN
+ || errno == ECONNREFUSED || errno == EADDRNOTAVAIL
+ ) {
+//TODO: always do this?
+ set_next(p, error_interval());
+ goto bail;
+ }
+ xfunc_die();
+ }
+
+ T4 = gettime();
+
+ if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
+ bb_error_msg("malformed packet received from %s", addr);
+ goto bail;
+ }
+
+ if (msg.orgtime.int_partl != p->query.msg.xmttime.int_partl
+ || msg.orgtime.fractionl != p->query.msg.xmttime.fractionl
+ ) {
+ goto bail;
+ }
+
+ if ((msg.status & LI_ALARM) == LI_ALARM
+ || msg.stratum == 0
+ || msg.stratum > NTP_MAXSTRATUM
+ ) {
+ interval = error_interval();
+ bb_info_msg("reply from %s: not synced, next query %ds", addr, (int) interval);
+ goto bail;
+ }
+
+ /*
+ * From RFC 2030 (with a correction to the delay math):
+ *
+ * Timestamp Name ID When Generated
+ * ------------------------------------------------------------
+ * Originate Timestamp T1 time request sent by client
+ * Receive Timestamp T2 time request received by server
+ * Transmit Timestamp T3 time reply sent by server
+ * Destination Timestamp T4 time reply received by client
+ *
+ * The roundtrip delay d and local clock offset t are defined as
+ *
+ * d = (T4 - T1) - (T3 - T2) t = ((T2 - T1) + (T3 - T4)) / 2.
+ */
+
+ T1 = p->query.xmttime;
+ T2 = lfp_to_d(msg.rectime);
+ T3 = lfp_to_d(msg.xmttime);
+
+ offset = &p->reply[p->shift];
+
+ offset->offset = ((T2 - T1) + (T3 - T4)) / 2;
+ offset->delay = (T4 - T1) - (T3 - T2);
+ if (offset->delay < 0) {
+ interval = error_interval();
+ set_next(p, interval);
+ bb_info_msg("reply from %s: negative delay %f", addr, p->reply[p->shift].delay);
+ goto bail;
+ }
+ offset->error = (T2 - T1) - (T3 - T4);
+ offset->rcvd = time(NULL);
+ offset->good = 1;
+
+ offset->status.leap = (msg.status & LI_MASK);
+ offset->status.precision = msg.precision;
+ offset->status.rootdelay = sfp_to_d(msg.rootdelay);
+ offset->status.rootdispersion = sfp_to_d(msg.dispersion);
+ offset->status.refid = ntohl(msg.refid);
+ offset->status.refid4 = msg.xmttime.fractionl;
+ offset->status.reftime = lfp_to_d(msg.reftime);
+ offset->status.poll = msg.ppoll;
+ offset->status.stratum = msg.stratum;
+
+ if (p->trustlevel < TRUSTLEVEL_PATHETIC)
+ interval = scale_interval(INTERVAL_QUERY_PATHETIC);
+ else if (p->trustlevel < TRUSTLEVEL_AGRESSIVE)
+ interval = scale_interval(INTERVAL_QUERY_AGRESSIVE);
+ else
+ interval = scale_interval(INTERVAL_QUERY_NORMAL);
+
+ set_next(p, interval);
+ p->state = STATE_REPLY_RECEIVED;
+
+ /* every received reply which we do not discard increases trust */
+ if (p->trustlevel < TRUSTLEVEL_MAX) {
+ if (p->trustlevel < TRUSTLEVEL_BADPEER
+ && p->trustlevel + 1 >= TRUSTLEVEL_BADPEER
+ ) {
+ bb_info_msg("peer %s now valid", addr);
+ }
+ p->trustlevel++;
+ }
+
+ bb_info_msg("reply from %s: offset %f delay %f, next query %ds", addr,
+ offset->offset, offset->delay, (int) interval);
+
+ client_update(p);
+ if (!G.settime)
+ settime(offset->offset);
+
+ if (++p->shift >= OFFSET_ARRAY_SIZE)
+ p->shift = 0;
+
+ bail:
+ free(addr);
+}
+
+#if ENABLE_FEATURE_NTPD_SERVER
+static void
+server_dispatch(int fd)
+{
+ ssize_t size;
+ uint8_t version;
+ double rectime;
+ len_and_sockaddr *to;
+ struct sockaddr *from;
+ ntp_msg_t query, reply;
+
+ to = get_sock_lsa(G.listen_fd);
+ from = xzalloc(to->len);
+
+ size = recv_from_to(fd, &query, sizeof(query), 0, from, &to->u.sa, to->len);
+ if (size == -1)
+ bb_error_msg_and_die("recv_from_to");
+ if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
+ char *addr = xmalloc_sockaddr2dotted_noport(from);
+ bb_error_msg("malformed packet received from %s", addr);
+ free(addr);
+ goto bail;
+ }
+
+ rectime = gettime();
+ version = (query.status & VERSION_MASK) >> 3;
+
+ memset(&reply, 0, sizeof(reply));
+ reply.status = G.status.synced ? G.status.leap : LI_ALARM;
+ reply.status |= (query.status & VERSION_MASK);
+ reply.status |= ((query.status & MODE_MASK) == MODE_CLIENT) ?
+ MODE_SERVER : MODE_SYM_PAS;
+ reply.stratum = G.status.stratum;
+ reply.ppoll = query.ppoll;
+ reply.precision = G.status.precision;
+ reply.rectime = d_to_lfp(rectime);
+ reply.reftime = d_to_lfp(G.status.reftime);
+ reply.xmttime = d_to_lfp(gettime());
+ reply.orgtime = query.xmttime;
+ reply.rootdelay = d_to_sfp(G.status.rootdelay);
+ reply.refid = (version > 3) ? G.status.refid4 : G.status.refid;
+
+ /* We reply from the address packet was sent to,
+ * this makes to/from look swapped here: */
+ sendmsg_wrap(fd, /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
+ &reply, size);
+
+ bail:
+ free(to);
+ free(from);
+}
+#endif
+
+/* Upstream ntpd's options:
+ *
+ * -4 Force DNS resolution of host names to the IPv4 namespace.
+ * -6 Force DNS resolution of host names to the IPv6 namespace.
+ * -a Require cryptographic authentication for broadcast client,
+ * multicast client and symmetric passive associations.
+ * This is the default.
+ * -A Do not require cryptographic authentication for broadcast client,
+ * multicast client and symmetric passive associations.
+ * This is almost never a good idea.
+ * -b Enable the client to synchronize to broadcast servers.
+ * -c conffile
+ * Specify the name and path of the configuration file,
+ * default /etc/ntp.conf
+ * -d Specify debugging mode. This option may occur more than once,
+ * with each occurrence indicating greater detail of display.
+ * -D level
+ * Specify debugging level directly.
+ * -f driftfile
+ * Specify the name and path of the frequency file.
+ * This is the same operation as the "driftfile FILE"
+ * configuration command.
+ * -g Normally, ntpd exits with a message to the system log
+ * if the offset exceeds the panic threshold, which is 1000 s
+ * by default. This option allows the time to be set to any value
+ * without restriction; however, this can happen only once.
+ * If the threshold is exceeded after that, ntpd will exit
+ * with a message to the system log. This option can be used
+ * with the -q and -x options. See the tinker command for other options.
+ * -i jaildir
+ * Chroot the server to the directory jaildir. This option also implies
+ * that the server attempts to drop root privileges at startup
+ * (otherwise, chroot gives very little additional security).
+ * You may need to also specify a -u option.
+ * -k keyfile
+ * Specify the name and path of the symmetric key file,
+ * default /etc/ntp/keys. This is the same operation
+ * as the "keys FILE" configuration command.
+ * -l logfile
+ * Specify the name and path of the log file. The default
+ * is the system log file. This is the same operation as
+ * the "logfile FILE" configuration command.
+ * -L Do not listen to virtual IPs. The default is to listen.
+ * -n Don't fork.
+ * -N To the extent permitted by the operating system,
+ * run the ntpd at the highest priority.
+ * -p pidfile
+ * Specify the name and path of the file used to record the ntpd
+ * process ID. This is the same operation as the "pidfile FILE"
+ * configuration command.
+ * -P priority
+ * To the extent permitted by the operating system,
+ * run the ntpd at the specified priority.
+ * -q Exit the ntpd just after the first time the clock is set.
+ * This behavior mimics that of the ntpdate program, which is
+ * to be retired. The -g and -x options can be used with this option.
+ * Note: The kernel time discipline is disabled with this option.
+ * -r broadcastdelay
+ * Specify the default propagation delay from the broadcast/multicast
+ * server to this client. This is necessary only if the delay
+ * cannot be computed automatically by the protocol.
+ * -s statsdir
+ * Specify the directory path for files created by the statistics
+ * facility. This is the same operation as the "statsdir DIR"
+ * configuration command.
+ * -t key
+ * Add a key number to the trusted key list. This option can occur
+ * more than once.
+ * -u user[:group]
+ * Specify a user, and optionally a group, to switch to.
+ * -v variable
+ * -V variable
+ * Add a system variable listed by default.
+ * -x Normally, the time is slewed if the offset is less than the step
+ * threshold, which is 128 ms by default, and stepped if above
+ * the threshold. This option sets the threshold to 600 s, which is
+ * well within the accuracy window to set the clock manually.
+ * Note: since the slew rate of typical Unix kernels is limited
+ * to 0.5 ms/s, each second of adjustment requires an amortization
+ * interval of 2000 s. Thus, an adjustment as much as 600 s
+ * will take almost 14 days to complete. This option can be used
+ * with the -g and -q options. See the tinker command for other options.
+ * Note: The kernel time discipline is disabled with this option.
+ */
+
+enum {
+ OPT_n = (1 << 0),
+ OPT_g = (1 << 1),
+ OPT_p = (1 << 2),
+ OPT_l = (1 << 3),
+};
+
+/* By doing init in a separate function we decrease stack usage
+ * in main loop.
+ */
+static NOINLINE void ntp_init(char **argv)
+{
+ unsigned opts;
+ llist_t *peers;
+
+ tzset();
+
+ if (getuid())
+ bb_error_msg_and_die("need root privileges");
+
+ peers = NULL;
+ opt_complementary = "dd:p::"; /* d: counter, p: list */
+ opts = getopt32(argv,
+ "ng" /* compat */
+ "p:"IF_FEATURE_NTPD_SERVER("l") /* NOT compat */
+ "d" /* compat */
+ "46aAbLNx", /* compat, ignored */
+ &peers, &G.verbose);
+#if ENABLE_FEATURE_NTPD_SERVER
+ G.listen_fd = -1;
+ if (opts & OPT_l) {
+ G.listen_fd = create_and_bind_dgram_or_die(NULL, 123);
+ socket_want_pktinfo(G.listen_fd);
+ setsockopt(G.listen_fd, IPPROTO_IP, IP_TOS, &const_IPTOS_LOWDELAY, sizeof(const_IPTOS_LOWDELAY));
+ }
+#endif
+ if (opts & OPT_g)
+ G.settime = 1;
+ while (peers)
+ add_peers(llist_pop(&peers));
+ if (!(opts & OPT_n)) {
+ logmode = LOGMODE_NONE;
+ bb_daemonize(DAEMON_DEVNULL_STDIO);
+ }
+
+ /* Set some globals */
+ {
+ int prec = 0;
+ int b;
+#if 0
+ struct timespec tp;
+ /* We can use sys_clock_getres but assuming 10ms tick should be fine */
+ clock_getres(CLOCK_REALTIME, &tp);
+ tp.tv_sec = 0;
+ tp.tv_nsec = 10000000;
+ b = 1000000000 / tp.tv_nsec; /* convert to Hz */
+#else
+ b = 100; /* b = 1000000000/10000000 = 100 */
+#endif
+ while (b > 1)
+ prec--, b >>= 1;
+ G.status.precision = prec;
+ }
+ G.scale = 1;
+ G.firstadj = 1;
+
+ bb_signals((1 << SIGTERM) | (1 << SIGINT), record_signo);
+ bb_signals((1 << SIGPIPE) | (1 << SIGHUP), SIG_IGN);
+}
+
+int ntpd_main(int argc UNUSED_PARAM, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ntpd_main(int argc UNUSED_PARAM, char **argv)
+{
+ struct globals g;
+ unsigned new_cnt;
+ struct pollfd *pfd;
+ ntp_peer_t **idx2peer;
+
+ memset(&g, 0, sizeof(g));
+ SET_PTR_TO_GLOBALS(&g);
+
+ ntp_init(argv);
+
+ new_cnt = g.peer_cnt;
+ idx2peer = xzalloc(sizeof(void *) * new_cnt);
+#if ENABLE_FEATURE_NTPD_SERVER
+ if (g.listen_fd != -1)
+ new_cnt++;
+#endif
+ pfd = xzalloc(sizeof(pfd[0]) * new_cnt);
+
+ while (!bb_got_signal) {
+ llist_t *item;
+ unsigned i, j, idx_peers;
+ unsigned sent_cnt, trial_cnt;
+ int nfds, timeout;
+ time_t nextaction;
+
+ nextaction = time(NULL) + 3600;
+
+ i = 0;
+#if ENABLE_FEATURE_NTPD_SERVER
+ if (g.listen_fd != -1) {
+ pfd[0].fd = g.listen_fd;
+ pfd[0].events = POLLIN;
+ i++;
+ }
+#endif
+ idx_peers = i;
+ sent_cnt = trial_cnt = 0;
+ for (item = g.ntp_peers; item != NULL; item = item->link) {
+ ntp_peer_t *p = (ntp_peer_t *) item->data;
+
+ if (p->next > 0 && p->next <= time(NULL)) {
+ trial_cnt++;
+ if (client_query(p) == 0)
+ sent_cnt++;
+ }
+ if (p->next > 0 && p->next < nextaction)
+ nextaction = p->next;
+ if (p->deadline > 0 && p->deadline < nextaction)
+ nextaction = p->deadline;
+
+ if (p->deadline > 0 && p->deadline <= time(NULL)) {
+ char *addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
+
+ timeout = error_interval();
+ bb_info_msg("no reply from %s received in time, "
+ "next query %ds", addr, timeout);
+ if (p->trustlevel >= TRUSTLEVEL_BADPEER) {
+ p->trustlevel /= 2;
+ if (p->trustlevel < TRUSTLEVEL_BADPEER)
+ bb_info_msg("peer %s now invalid", addr);
+ }
+ free(addr);
+
+ set_next(p, timeout);
+ }
+
+ if (p->state == STATE_QUERY_SENT) {
+ pfd[i].fd = p->query.fd;
+ pfd[i].events = POLLIN;
+ idx2peer[i - idx_peers] = p;
+ i++;
+ }
+ }
+
+ if (g.settime
+ && ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0)
+ ) {
+ settime(0); /* no good peers, don't wait */
+ }
+
+ timeout = nextaction - time(NULL);
+ if (timeout < 0)
+ timeout = 0;
+
+ if (g.verbose)
+ bb_error_msg("entering poll %u secs", timeout);
+ nfds = poll(pfd, i, timeout * 1000);
+
+ j = 0;
+#if ENABLE_FEATURE_NTPD_SERVER
+ for (; nfds > 0 && j < idx_peers; j++) {
+ if (pfd[j].revents & (POLLIN|POLLERR)) {
+ nfds--;
+ server_dispatch(pfd[j].fd);
+ }
+ }
+#endif
+ for (; nfds > 0 && j < i; j++) {
+ if (pfd[j].revents & (POLLIN|POLLERR)) {
+ nfds--;
+ client_dispatch(idx2peer[j - idx_peers]);
+ }
+ }
+ } /* while (!bb_got_signal) */
+
+ kill_myself_with_sig(bb_got_signal);
+}