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ntpd: use MSG_DONTWAIT; better readability

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function                                             old     new   delta
gettime_fp                                             -      39     +39
ntpd_main                                           3214    3199     -15
gettime                                               47       -     -47
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/1 up/down: 39/-62)            Total: -23 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-11-24 14:04:15 +01:00
parent ca6c7e42f9
commit 363e89b1ee
1 changed files with 113 additions and 106 deletions
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219
networking/ntpd.c
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@ -16,7 +16,7 @@
#define INTERVAL_QUERY_PATHETIC 60 #define INTERVAL_QUERY_PATHETIC 60
#define INTERVAL_QUERY_AGRESSIVE 5 #define INTERVAL_QUERY_AGRESSIVE 5
#define TRUSTLEVEL_BADPEER 6 #define TRUSTLEVEL_BADPEER 6 /* bad if *less than* TRUSTLEVEL_BADPEER */
#define TRUSTLEVEL_PATHETIC 2 #define TRUSTLEVEL_PATHETIC 2
#define TRUSTLEVEL_AGRESSIVE 8 #define TRUSTLEVEL_AGRESSIVE 8
#define TRUSTLEVEL_MAX 10 #define TRUSTLEVEL_MAX 10
@ -214,14 +214,13 @@ add_peers(const char *s)
} }
static double static double
gettime(void) gettime_fp(void)
{ {
struct timeval tv; struct timeval tv;
gettimeofday(&tv, NULL); /* never fails */ gettimeofday(&tv, NULL); /* never fails */
return (tv.tv_sec + JAN_1970 + 1.0e-6 * tv.tv_usec); return (tv.tv_sec + 1.0e-6 * tv.tv_usec + JAN_1970);
} }
static void static void
d_to_tv(double d, struct timeval *tv) d_to_tv(double d, struct timeval *tv)
{ {
@ -298,9 +297,9 @@ sendmsg_wrap(int fd,
errno = 0; errno = 0;
if (!from) { if (!from) {
ret = sendto(fd, msg, len, 0, to, addrlen); ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen);
} else { } else {
ret = send_to_from(fd, msg, len, 0, to, from, addrlen); ret = send_to_from(fd, msg, len, MSG_DONTWAIT, to, from, addrlen);
} }
if (ret != len) { if (ret != len) {
bb_perror_msg("send failed"); bb_perror_msg("send failed");
@ -310,7 +309,7 @@ sendmsg_wrap(int fd,
} }
static int static int
client_query(ntp_peer_t *p) send_query_to_peer(ntp_peer_t *p)
{ {
if (p->query.fd == -1) { if (p->query.fd == -1) {
p->query.fd = xsocket(p->lsa->u.sa.sa_family, SOCK_DGRAM, 0); p->query.fd = xsocket(p->lsa->u.sa.sa_family, SOCK_DGRAM, 0);
@ -336,7 +335,7 @@ client_query(ntp_peer_t *p)
p->query.msg.xmttime.int_partl = random(); p->query.msg.xmttime.int_partl = random();
p->query.msg.xmttime.fractionl = random(); p->query.msg.xmttime.fractionl = random();
p->query.xmttime = gettime(); p->query.xmttime = gettime_fp();
if (sendmsg_wrap(p->query.fd, /*from:*/ NULL, /*to:*/ &p->lsa->u.sa, /*addrlen:*/ p->lsa->len, if (sendmsg_wrap(p->query.fd, /*from:*/ NULL, /*to:*/ &p->lsa->u.sa, /*addrlen:*/ p->lsa->len,
&p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) { &p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) {
@ -377,6 +376,7 @@ adjtime_wrap(void)
{ {
ntp_peer_t *p; ntp_peer_t *p;
unsigned offset_cnt; unsigned offset_cnt;
unsigned middle;
int i = 0; int i = 0;
ntp_peer_t **peers; ntp_peer_t **peers;
double offset_median; double offset_median;
@ -394,7 +394,10 @@ adjtime_wrap(void)
offset_cnt++; offset_cnt++;
} }
peers = xzalloc(sizeof(ntp_peer_t *) * offset_cnt); if (offset_cnt == 0)
goto clear_good;
peers = xzalloc(sizeof(peers[0]) * offset_cnt);
for (item = G.ntp_peers; item != NULL; item = item->link) { for (item = G.ntp_peers; item != NULL; item = item->link) {
p = (ntp_peer_t *) item->data; p = (ntp_peer_t *) item->data;
if (p->trustlevel < TRUSTLEVEL_BADPEER) if (p->trustlevel < TRUSTLEVEL_BADPEER)
@ -402,62 +405,55 @@ adjtime_wrap(void)
peers[i++] = p; peers[i++] = p;
} }
qsort(peers, offset_cnt, sizeof(ntp_peer_t *), offset_compare); qsort(peers, offset_cnt, sizeof(peers[0]), offset_compare);
if (offset_cnt != 0) { middle = offset_cnt / 2;
if ((offset_cnt & 1) == 0) { if ((offset_cnt & 1) == 0) {
//TODO: try offset_cnt /= 2... offset_median = (peers[middle-1]->update.offset + peers[middle]->update.offset) / 2;
offset_median = G.status.rootdelay = (peers[middle-1]->update.delay + peers[middle]->update.delay) / 2;
(peers[offset_cnt / 2 - 1]->update.offset + G.status.stratum = MAX(peers[middle-1]->update.status.stratum, peers[middle]->update.status.stratum);
peers[offset_cnt / 2]->update.offset) / 2; } else {
G.status.rootdelay = offset_median = peers[middle]->update.offset;
(peers[offset_cnt / 2 - 1]->update.delay + G.status.rootdelay = peers[middle]->update.delay;
peers[offset_cnt / 2]->update.delay) / 2; G.status.stratum = peers[middle]->update.status.stratum;
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;
} }
G.status.leap = peers[middle]->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_fp();
G.status.stratum++; /* one more than selected peer */
G.scale = updated_scale(offset_median);
G.status.refid4 = peers[middle]->update.status.refid4;
lsa = peers[middle]->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); free(peers);
clear_good:
for (item = G.ntp_peers; item != NULL; item = item->link) { for (item = G.ntp_peers; item != NULL; item = item->link) {
p = (ntp_peer_t *) item->data; p = (ntp_peer_t *) item->data;
p->update.good = 0; p->update.good = 0;
@ -514,7 +510,7 @@ settime(double offset)
} }
static void static void
client_update(ntp_peer_t *p) update_peer_data(ntp_peer_t *p)
{ {
int i, best = 0, good = 0; int i, best = 0, good = 0;
@ -561,7 +557,7 @@ scale_interval(time_t requested)
} }
static void static void
client_dispatch(ntp_peer_t *p) recv_and_process_peer_pkt(ntp_peer_t *p)
{ {
char *addr; char *addr;
ssize_t size; ssize_t size;
@ -572,13 +568,13 @@ client_dispatch(ntp_peer_t *p)
addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa); addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
//TODO: use MSG_DONTWAIT flag? size = recv(p->query.fd, &msg, sizeof(msg), MSG_DONTWAIT);
size = recv(p->query.fd, &msg, sizeof(msg), 0);
if (size == -1) { if (size == -1) {
bb_perror_msg("recv(%s) error", addr); bb_perror_msg("recv(%s) error", addr);
if (errno == EHOSTUNREACH || errno == EHOSTDOWN if (errno == EHOSTUNREACH || errno == EHOSTDOWN
|| errno == ENETUNREACH || errno == ENETDOWN || errno == ENETUNREACH || errno == ENETDOWN
|| errno == ECONNREFUSED || errno == EADDRNOTAVAIL || errno == ECONNREFUSED || errno == EADDRNOTAVAIL
|| errno == EAGAIN
) { ) {
//TODO: always do this? //TODO: always do this?
set_next(p, error_interval()); set_next(p, error_interval());
@ -587,7 +583,7 @@ client_dispatch(ntp_peer_t *p)
xfunc_die(); xfunc_die();
} }
T4 = gettime(); T4 = gettime_fp();
if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) { if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
bb_error_msg("malformed packet received from %s", addr); bb_error_msg("malformed packet received from %s", addr);
@ -639,6 +635,7 @@ client_dispatch(ntp_peer_t *p)
goto bail; goto bail;
} }
offset->error = (T2 - T1) - (T3 - T4); offset->error = (T2 - T1) - (T3 - T4);
// Can we use (T4 - JAN_1970) instead of time(NULL)?
offset->rcvd = time(NULL); offset->rcvd = time(NULL);
offset->good = 1; offset->good = 1;
@ -664,21 +661,19 @@ client_dispatch(ntp_peer_t *p)
/* every received reply which we do not discard increases trust */ /* every received reply which we do not discard increases trust */
if (p->trustlevel < TRUSTLEVEL_MAX) { 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++; p->trustlevel++;
if (p->trustlevel == TRUSTLEVEL_BADPEER)
bb_info_msg("peer %s now valid", addr);
} }
bb_info_msg("reply from %s: offset %f delay %f, next query %ds", addr, bb_info_msg("reply from %s: offset %f delay %f, next query %ds", addr,
offset->offset, offset->delay, (int) interval); offset->offset, offset->delay, (int) interval);
client_update(p); update_peer_data(p);
settime(offset->offset); settime(offset->offset);
if (++p->shift >= OFFSET_ARRAY_SIZE) p->shift++;
if (p->shift >= OFFSET_ARRAY_SIZE)
p->shift = 0; p->shift = 0;
bail: bail:
@ -687,7 +682,7 @@ client_dispatch(ntp_peer_t *p)
#if ENABLE_FEATURE_NTPD_SERVER #if ENABLE_FEATURE_NTPD_SERVER
static void static void
server_dispatch(int fd) recv_and_process_client_pkt(void /*int fd*/)
{ {
ssize_t size; ssize_t size;
uint8_t version; uint8_t version;
@ -702,12 +697,14 @@ server_dispatch(int fd)
to = get_sock_lsa(G.listen_fd); to = get_sock_lsa(G.listen_fd);
from = xzalloc(to->len); from = xzalloc(to->len);
//TODO: use MGS_DONTWAIT flag? size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len);
size = recv_from_to(fd, &msg, sizeof(msg), 0, from, &to->u.sa, to->len);
if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) { if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) {
char *addr; char *addr;
if (size < 0) if (size < 0) {
bb_error_msg_and_die("recv_from_to"); if (errno == EAGAIN)
goto bail;
bb_perror_msg_and_die("recv_from_to");
}
addr = xmalloc_sockaddr2dotted_noport(from); addr = xmalloc_sockaddr2dotted_noport(from);
bb_error_msg("malformed packet received from %s", addr); bb_error_msg("malformed packet received from %s", addr);
free(addr); free(addr);
@ -727,18 +724,18 @@ server_dispatch(int fd)
msg.stratum = G.status.stratum; msg.stratum = G.status.stratum;
msg.ppoll = query_ppoll; msg.ppoll = query_ppoll;
msg.precision = G.status.precision; msg.precision = G.status.precision;
rectime = gettime(); rectime = gettime_fp();
msg.xmttime = msg.rectime = d_to_lfp(rectime); msg.xmttime = msg.rectime = d_to_lfp(rectime);
msg.reftime = d_to_lfp(G.status.reftime); msg.reftime = d_to_lfp(G.status.reftime);
//msg.xmttime = d_to_lfp(gettime()); // = msg.rectime //msg.xmttime = d_to_lfp(gettime_fp()); // = msg.rectime
msg.orgtime = query_xmttime; msg.orgtime = query_xmttime;
msg.rootdelay = d_to_sfp(G.status.rootdelay); msg.rootdelay = d_to_sfp(G.status.rootdelay);
version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */ version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */
msg.refid = (version > (3 << VERSION_SHIFT)) ? G.status.refid4 : G.status.refid; msg.refid = (version > (3 << VERSION_SHIFT)) ? G.status.refid4 : G.status.refid;
/* We reply from the address packet was sent to, /* We reply from the local address packet was sent to,
* this makes to/from look swapped here: */ * this makes to/from look swapped here: */
sendmsg_wrap(fd, sendmsg_wrap(G.listen_fd,
/*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len, /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len,
&msg, size); &msg, size);
@ -910,20 +907,23 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
ntp_init(argv); ntp_init(argv);
{ {
unsigned new_cnt = g.peer_cnt; unsigned cnt = g.peer_cnt;
idx2peer = xzalloc(sizeof(void *) * new_cnt);
/* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */ /* if ENABLE_FEATURE_NTPD_SERVER, + 1 for listen_fd: */
pfd = xzalloc(sizeof(pfd[0]) * (new_cnt + ENABLE_FEATURE_NTPD_SERVER)); idx2peer = xzalloc(sizeof(void *) * (cnt + ENABLE_FEATURE_NTPD_SERVER));
pfd = xzalloc(sizeof(pfd[0]) * (cnt + ENABLE_FEATURE_NTPD_SERVER));
} }
while (!bb_got_signal) { while (!bb_got_signal) {
llist_t *item; llist_t *item;
unsigned i, j, first_peer_idx; unsigned i, j;
unsigned sent_cnt, trial_cnt; unsigned sent_cnt, trial_cnt;
int nfds, timeout; int nfds, timeout;
time_t nextaction; time_t cur_time, nextaction;
nextaction = time(NULL) + 3600; /* Nothing between here and poll() blocks for any significant time */
cur_time = time(NULL);
nextaction = cur_time + 3600;
i = 0; i = 0;
#if ENABLE_FEATURE_NTPD_SERVER #if ENABLE_FEATURE_NTPD_SERVER
@ -933,22 +933,19 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
i++; i++;
} }
#endif #endif
first_peer_idx = i; /* Pass over peer list, send requests, time out on receives */
sent_cnt = trial_cnt = 0; sent_cnt = trial_cnt = 0;
for (item = g.ntp_peers; item != NULL; item = item->link) { for (item = g.ntp_peers; item != NULL; item = item->link) {
ntp_peer_t *p = (ntp_peer_t *) item->data; ntp_peer_t *p = (ntp_peer_t *) item->data;
if (p->next > 0 && p->next <= time(NULL)) { if (p->next != 0 && p->next <= cur_time) {
/* Time to send new req */
trial_cnt++; trial_cnt++;
if (client_query(p) == 0) if (send_query_to_peer(p) == 0)
sent_cnt++; sent_cnt++;
} }
if (p->next > 0 && p->next < nextaction) if (p->deadline != 0 && p->deadline <= cur_time) {
nextaction = p->next; /* Timed out waiting for reply */
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); char *addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa);
timeout = error_interval(); timeout = error_interval();
@ -964,39 +961,49 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
set_next(p, timeout); set_next(p, timeout);
} }
if (p->next != 0 && p->next < nextaction)
nextaction = p->next;
if (p->deadline != 0 && p->deadline < nextaction)
nextaction = p->deadline;
if (p->state == STATE_QUERY_SENT) { if (p->state == STATE_QUERY_SENT) {
/* Wait for reply from this peer */
pfd[i].fd = p->query.fd; pfd[i].fd = p->query.fd;
pfd[i].events = POLLIN; pfd[i].events = POLLIN;
idx2peer[i - first_peer_idx] = p; idx2peer[i] = p;
i++; i++;
} }
} }
if ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0) if ((trial_cnt > 0 && sent_cnt == 0) || g.peer_cnt == 0)
settime(0); /* no good peers, don't wait */ settime(0); /* no good peers, don't wait */
timeout = nextaction - time(NULL); timeout = nextaction - cur_time;
if (timeout < 0) if (timeout < 0)
timeout = 0; timeout = 0;
/* Here we may block */
if (g.verbose) if (g.verbose)
bb_error_msg("entering poll %u secs", timeout); bb_error_msg("entering poll %u secs", timeout);
nfds = poll(pfd, i, timeout * 1000); nfds = poll(pfd, i, timeout * 1000);
if (nfds <= 0)
continue;
/* Process any received packets */
j = 0; j = 0;
#if ENABLE_FEATURE_NTPD_SERVER #if ENABLE_FEATURE_NTPD_SERVER
//TODO: simplify. There is only one server fd! if (g.listen_fd != -1) {
for (; nfds > 0 && j < first_peer_idx; j++) { if (pfd[0].revents /* & (POLLIN|POLLERR)*/) {
if (pfd[j].revents & (POLLIN|POLLERR)) {
nfds--; nfds--;
server_dispatch(pfd[j].fd); recv_and_process_client_pkt(/*g.listen_fd*/);
} }
j = 1;
} }
#endif #endif
for (; nfds > 0 && j < i; j++) { for (; nfds != 0 && j < i; j++) {
if (pfd[j].revents & (POLLIN|POLLERR)) { if (pfd[j].revents /* & (POLLIN|POLLERR)*/) {
nfds--; nfds--;
client_dispatch(idx2peer[j - first_peer_idx]); recv_and_process_peer_pkt(idx2peer[j]);
} }
} }
} /* while (!bb_got_signal) */ } /* while (!bb_got_signal) */