d531f93f6
Denys Vlasenko
2014-04-19
Subject
ntpd: truly ignore high delay packet
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networking/ntpd.c+20 -15
| @@ -252,6 +252,9 @@ typedef struct { | |
| * or when receive times out (if p_fd >= 0): */ | |
| double next_action_time; | |
| double p_xmttime; | |
| + | double p_raw_delay; |
| + | /* p_raw_delay is set even by "high delay" packets */ |
| + | /* lastpkt_delay isn't */ |
| double lastpkt_recv_time; | |
| double lastpkt_delay; | |
| double lastpkt_rootdelay; | |
| @@ -1685,7 +1688,8 @@ recv_and_process_peer_pkt(peer_t *p) | |
| ssize_t size; | |
| msg_t msg; | |
| double T1, T2, T3, T4; | |
| - | double dv, offset; |
| + | double offset; |
| + | double prev_delay, delay; |
| unsigned interval; | |
| datapoint_t *datapoint; | |
| peer_t *q; | |
| @@ -1745,12 +1749,6 @@ recv_and_process_peer_pkt(peer_t *p) | |
| // if (msg.m_rootdelay / 2 + msg.m_rootdisp >= MAXDISP || p->lastpkt_reftime > msg.m_xmt) | |
| // return; /* invalid header values */ | |
| - | p->lastpkt_status = msg.m_status; |
| - | p->lastpkt_stratum = msg.m_stratum; |
| - | p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay); |
| - | p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp); |
| - | p->lastpkt_refid = msg.m_refid; |
| - | |
| /* | |
| * From RFC 2030 (with a correction to the delay math): | |
| * | |
| @@ -1770,28 +1768,35 @@ recv_and_process_peer_pkt(peer_t *p) | |
| T3 = lfp_to_d(msg.m_xmttime); | |
| T4 = G.cur_time; | |
| - | p->lastpkt_recv_time = T4; |
| - | VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time); |
| - | |
| /* The delay calculation is a special case. In cases where the | |
| * server and client clocks are running at different rates and | |
| * with very fast networks, the delay can appear negative. In | |
| * order to avoid violating the Principle of Least Astonishment, | |
| * the delay is clamped not less than the system precision. | |
| */ | |
| - | dv = p->lastpkt_delay; |
| - | p->lastpkt_delay = (T4 - T1) - (T3 - T2); |
| - | if (p->lastpkt_delay < G_precision_sec) |
| - | p->lastpkt_delay = G_precision_sec; |
| + | delay = (T4 - T1) - (T3 - T2); |
| + | if (delay < G_precision_sec) |
| + | delay = G_precision_sec; |
| /* | |
| * If this packet's delay is much bigger than the last one, | |
| * it's better to just ignore it than use its much less precise value. | |
| */ | |
| - | if (p->reachable_bits && p->lastpkt_delay > dv * BAD_DELAY_GROWTH) { |
| + | prev_delay = p->p_raw_delay; |
| + | p->p_raw_delay = delay; |
| + | if (p->reachable_bits && delay > prev_delay * BAD_DELAY_GROWTH) { |
| bb_error_msg("reply from %s: delay %f is too high, ignoring", p->p_dotted, p->lastpkt_delay); | |
| goto pick_normal_interval; | |
| } | |
| + | p->lastpkt_delay = delay; |
| + | p->lastpkt_recv_time = T4; |
| + | VERB6 bb_error_msg("%s->lastpkt_recv_time=%f", p->p_dotted, p->lastpkt_recv_time); |
| + | p->lastpkt_status = msg.m_status; |
| + | p->lastpkt_stratum = msg.m_stratum; |
| + | p->lastpkt_rootdelay = sfp_to_d(msg.m_rootdelay); |
| + | p->lastpkt_rootdisp = sfp_to_d(msg.m_rootdisp); |
| + | p->lastpkt_refid = msg.m_refid; |
| + | |
| p->datapoint_idx = p->reachable_bits ? (p->datapoint_idx + 1) % NUM_DATAPOINTS : 0; | |
| datapoint = &p->filter_datapoint[p->datapoint_idx]; | |
| datapoint->d_recv_time = T4; | |