From 4125a6b6306d8d12f1e22239465bce916e168d73 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 11 Jun 2012 11:41:46 +0200 Subject: [PATCH] ntpd: on time step, kill all outstanding replies from other peers Signed-off-by: Denys Vlasenko --- networking/ntpd.c | 50 ++++++++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 20 deletions(-) diff --git a/networking/ntpd.c b/networking/ntpd.c index 603801ec6..72e9d0be2 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -220,14 +220,14 @@ typedef struct { typedef struct { len_and_sockaddr *p_lsa; char *p_dotted; - /* when to send new query (if p_fd == -1) - * or when receive times out (if p_fd >= 0): */ int p_fd; int datapoint_idx; uint32_t lastpkt_refid; uint8_t lastpkt_status; uint8_t lastpkt_stratum; uint8_t reachable_bits; + /* when to send new query (if p_fd == -1) + * or when receive times out (if p_fd >= 0): */ double next_action_time; double p_xmttime; double lastpkt_recv_time; @@ -895,6 +895,11 @@ step_time(double offset) /* Correct various fields which contain time-relative values: */ + /* Globals: */ + G.cur_time += offset; + G.last_update_recv_time += offset; + G.last_script_run += offset; + /* p->lastpkt_recv_time, p->next_action_time and such: */ for (item = G.ntp_peers; item != NULL; item = item->link) { peer_t *pp = (peer_t *) item->data; @@ -902,11 +907,16 @@ step_time(double offset) //bb_error_msg("offset:%+f pp->next_action_time:%f -> %f", // offset, pp->next_action_time, pp->next_action_time + offset); pp->next_action_time += offset; + if (pp->p_fd >= 0) { + /* We wait for reply from this peer too. + * But due to step we are doing, reply's data is no longer + * useful (in fact, it'll be bogus). Stop waiting for it. + */ + close(pp->p_fd); + pp->p_fd = -1; + set_next(pp, RETRY_INTERVAL); + } } - /* Globals: */ - G.cur_time += offset; - G.last_update_recv_time += offset; - G.last_script_run += offset; } @@ -1623,22 +1633,30 @@ recv_and_process_peer_pkt(peer_t *p) ) { //TODO: always do this? interval = retry_interval(); - goto set_next_and_close_sock; + goto set_next_and_ret; } xfunc_die(); } if (size != NTP_MSGSIZE_NOAUTH && size != NTP_MSGSIZE) { bb_error_msg("malformed packet received from %s", p->p_dotted); - goto bail; + return; } if (msg.m_orgtime.int_partl != p->p_xmt_msg.m_xmttime.int_partl || msg.m_orgtime.fractionl != p->p_xmt_msg.m_xmttime.fractionl ) { - goto bail; + /* Somebody else's packet */ + return; } + /* We do not expect any more packets from this peer for now. + * Closing the socket informs kernel about it. + * We open a new socket when we send a new query. + */ + close(p->p_fd); + p->p_fd = -1; + if ((msg.m_status & LI_ALARM) == LI_ALARM || msg.m_stratum == 0 || msg.m_stratum > NTP_MAXSTRATUM @@ -1647,8 +1665,8 @@ recv_and_process_peer_pkt(peer_t *p) // "DENY", "RSTR" - peer does not like us at all // "RATE" - peer is overloaded, reduce polling freq interval = poll_interval(0); - bb_error_msg("reply from %s: not synced, next query in %us", p->p_dotted, interval); - goto set_next_and_close_sock; + bb_error_msg("reply from %s: peer is unsynced, next query in %us", p->p_dotted, interval); + goto set_next_and_ret; } // /* Verify valid root distance */ @@ -1794,16 +1812,8 @@ recv_and_process_peer_pkt(peer_t *p) /* Decide when to send new query for this peer */ interval = poll_interval(0); - set_next_and_close_sock: + set_next_and_ret: set_next(p, interval); - /* We do not expect any more packets from this peer for now. - * Closing the socket informs kernel about it. - * We open a new socket when we send a new query. - */ - close(p->p_fd); - p->p_fd = -1; - bail: - return; } #if ENABLE_FEATURE_NTPD_SERVER -- 2.25.1