From: Denys Vlasenko Date: Tue, 24 Nov 2009 13:04:15 +0000 (+0100) Subject: ntpd: use MSG_DONTWAIT; better readability X-Git-Tag: 1_16_0~204 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=363e89b1ee7a70e1328370e7c0db2852d06c15bf;p=oweals%2Fbusybox.git ntpd: use MSG_DONTWAIT; better readability 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 --- diff --git a/networking/ntpd.c b/networking/ntpd.c index 4e661ce98..fb82fd309 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -16,7 +16,7 @@ #define INTERVAL_QUERY_PATHETIC 60 #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_AGRESSIVE 8 #define TRUSTLEVEL_MAX 10 @@ -214,14 +214,13 @@ add_peers(const char *s) } static double -gettime(void) +gettime_fp(void) { struct timeval tv; 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 d_to_tv(double d, struct timeval *tv) { @@ -298,9 +297,9 @@ sendmsg_wrap(int fd, errno = 0; if (!from) { - ret = sendto(fd, msg, len, 0, to, addrlen); + ret = sendto(fd, msg, len, MSG_DONTWAIT, to, addrlen); } 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) { bb_perror_msg("send failed"); @@ -310,7 +309,7 @@ sendmsg_wrap(int fd, } static int -client_query(ntp_peer_t *p) +send_query_to_peer(ntp_peer_t *p) { if (p->query.fd == -1) { 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.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, &p->query.msg, NTP_MSGSIZE_NOAUTH) == -1) { @@ -377,6 +376,7 @@ adjtime_wrap(void) { ntp_peer_t *p; unsigned offset_cnt; + unsigned middle; int i = 0; ntp_peer_t **peers; double offset_median; @@ -394,7 +394,10 @@ adjtime_wrap(void) 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) { p = (ntp_peer_t *) item->data; if (p->trustlevel < TRUSTLEVEL_BADPEER) @@ -402,62 +405,55 @@ adjtime_wrap(void) 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; + qsort(peers, offset_cnt, sizeof(peers[0]), offset_compare); - bb_info_msg("adjusting local clock by %fs", offset_median); + middle = offset_cnt / 2; + if ((offset_cnt & 1) == 0) { + offset_median = (peers[middle-1]->update.offset + peers[middle]->update.offset) / 2; + G.status.rootdelay = (peers[middle-1]->update.delay + peers[middle]->update.delay) / 2; + G.status.stratum = MAX(peers[middle-1]->update.status.stratum, peers[middle]->update.status.stratum); + } else { + offset_median = peers[middle]->update.offset; + G.status.rootdelay = peers[middle]->update.delay; + G.status.stratum = peers[middle]->update.status.stratum; + } + G.status.leap = peers[middle]->update.status.leap; - 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; - } + bb_info_msg("adjusting local clock by %fs", offset_median); - G.firstadj = 0; - G.status.reftime = gettime(); - G.status.stratum++; /* one more than selected peer */ - G.scale = updated_scale(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[offset_cnt / 2]->update.status.refid4; + G.status.refid4 = peers[middle]->update.status.refid4; - lsa = peers[offset_cnt / 2]->lsa; - G.status.refid = + lsa = peers[middle]->lsa; + G.status.refid = #if ENABLE_FEATURE_IPV6 - lsa->u.sa.sa_family != AF_INET ? - G.status.refid4 : + lsa->u.sa.sa_family != AF_INET ? + G.status.refid4 : #endif - lsa->u.sin.sin_addr.s_addr; - } + lsa->u.sin.sin_addr.s_addr; free(peers); + clear_good: for (item = G.ntp_peers; item != NULL; item = item->link) { p = (ntp_peer_t *) item->data; p->update.good = 0; @@ -514,7 +510,7 @@ settime(double offset) } static void -client_update(ntp_peer_t *p) +update_peer_data(ntp_peer_t *p) { int i, best = 0, good = 0; @@ -561,7 +557,7 @@ scale_interval(time_t requested) } static void -client_dispatch(ntp_peer_t *p) +recv_and_process_peer_pkt(ntp_peer_t *p) { char *addr; ssize_t size; @@ -572,13 +568,13 @@ client_dispatch(ntp_peer_t *p) addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa); -//TODO: use MSG_DONTWAIT flag? - size = recv(p->query.fd, &msg, sizeof(msg), 0); + size = recv(p->query.fd, &msg, sizeof(msg), MSG_DONTWAIT); if (size == -1) { bb_perror_msg("recv(%s) error", addr); if (errno == EHOSTUNREACH || errno == EHOSTDOWN || errno == ENETUNREACH || errno == ENETDOWN || errno == ECONNREFUSED || errno == EADDRNOTAVAIL + || errno == EAGAIN ) { //TODO: always do this? set_next(p, error_interval()); @@ -587,7 +583,7 @@ client_dispatch(ntp_peer_t *p) xfunc_die(); } - T4 = gettime(); + T4 = gettime_fp(); if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) { bb_error_msg("malformed packet received from %s", addr); @@ -639,6 +635,7 @@ client_dispatch(ntp_peer_t *p) goto bail; } offset->error = (T2 - T1) - (T3 - T4); +// Can we use (T4 - JAN_1970) instead of time(NULL)? offset->rcvd = time(NULL); offset->good = 1; @@ -664,21 +661,19 @@ client_dispatch(ntp_peer_t *p) /* 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++; + 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, offset->offset, offset->delay, (int) interval); - client_update(p); + update_peer_data(p); settime(offset->offset); - if (++p->shift >= OFFSET_ARRAY_SIZE) + p->shift++; + if (p->shift >= OFFSET_ARRAY_SIZE) p->shift = 0; bail: @@ -687,7 +682,7 @@ client_dispatch(ntp_peer_t *p) #if ENABLE_FEATURE_NTPD_SERVER static void -server_dispatch(int fd) +recv_and_process_client_pkt(void /*int fd*/) { ssize_t size; uint8_t version; @@ -702,12 +697,14 @@ server_dispatch(int fd) to = get_sock_lsa(G.listen_fd); from = xzalloc(to->len); -//TODO: use MGS_DONTWAIT flag? - size = recv_from_to(fd, &msg, sizeof(msg), 0, from, &to->u.sa, to->len); + size = recv_from_to(G.listen_fd, &msg, sizeof(msg), MSG_DONTWAIT, from, &to->u.sa, to->len); if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) { char *addr; - if (size < 0) - bb_error_msg_and_die("recv_from_to"); + if (size < 0) { + if (errno == EAGAIN) + goto bail; + bb_perror_msg_and_die("recv_from_to"); + } addr = xmalloc_sockaddr2dotted_noport(from); bb_error_msg("malformed packet received from %s", addr); free(addr); @@ -727,18 +724,18 @@ server_dispatch(int fd) msg.stratum = G.status.stratum; msg.ppoll = query_ppoll; msg.precision = G.status.precision; - rectime = gettime(); + rectime = gettime_fp(); msg.xmttime = msg.rectime = d_to_lfp(rectime); 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.rootdelay = d_to_sfp(G.status.rootdelay); version = (query_status & VERSION_MASK); /* ... >> VERSION_SHIFT - done below instead */ 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: */ - sendmsg_wrap(fd, + sendmsg_wrap(G.listen_fd, /*from:*/ &to->u.sa, /*to:*/ from, /*addrlen:*/ to->len, &msg, size); @@ -910,20 +907,23 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv) ntp_init(argv); { - unsigned new_cnt = g.peer_cnt; - idx2peer = xzalloc(sizeof(void *) * new_cnt); + unsigned cnt = g.peer_cnt; /* 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) { llist_t *item; - unsigned i, j, first_peer_idx; + unsigned i, j; unsigned sent_cnt, trial_cnt; 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; #if ENABLE_FEATURE_NTPD_SERVER @@ -933,22 +933,19 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv) i++; } #endif - first_peer_idx = i; + /* Pass over peer list, send requests, time out on receives */ 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)) { + if (p->next != 0 && p->next <= cur_time) { + /* Time to send new req */ trial_cnt++; - if (client_query(p) == 0) + if (send_query_to_peer(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)) { + if (p->deadline != 0 && p->deadline <= cur_time) { + /* Timed out waiting for reply */ char *addr = xmalloc_sockaddr2dotted_noport(&p->lsa->u.sa); timeout = error_interval(); @@ -964,39 +961,49 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv) 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) { + /* Wait for reply from this peer */ pfd[i].fd = p->query.fd; pfd[i].events = POLLIN; - idx2peer[i - first_peer_idx] = p; + idx2peer[i] = p; i++; } } 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) timeout = 0; + /* Here we may block */ if (g.verbose) bb_error_msg("entering poll %u secs", timeout); nfds = poll(pfd, i, timeout * 1000); + if (nfds <= 0) + continue; + /* Process any received packets */ j = 0; #if ENABLE_FEATURE_NTPD_SERVER -//TODO: simplify. There is only one server fd! - for (; nfds > 0 && j < first_peer_idx; j++) { - if (pfd[j].revents & (POLLIN|POLLERR)) { + if (g.listen_fd != -1) { + if (pfd[0].revents /* & (POLLIN|POLLERR)*/) { nfds--; - server_dispatch(pfd[j].fd); + recv_and_process_client_pkt(/*g.listen_fd*/); } + j = 1; } #endif - for (; nfds > 0 && j < i; j++) { - if (pfd[j].revents & (POLLIN|POLLERR)) { + for (; nfds != 0 && j < i; j++) { + if (pfd[j].revents /* & (POLLIN|POLLERR)*/) { nfds--; - client_dispatch(idx2peer[j - first_peer_idx]); + recv_and_process_peer_pkt(idx2peer[j]); } } } /* while (!bb_got_signal) */