diff options
| -rw-r--r-- | networking/ntpd.c | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/networking/ntpd.c b/networking/ntpd.c index 8f792d16d..e0c9810a1 100644 --- a/networking/ntpd.c +++ b/networking/ntpd.c @@ -155,7 +155,8 @@ #define RETRY_INTERVAL 32 /* on send/recv error, retry in N secs (need to be power of 2) */ #define NOREPLY_INTERVAL 512 /* sent, but got no reply: cap next query by this many seconds */ #define RESPONSE_INTERVAL 16 /* wait for reply up to N secs */ -#define HOSTNAME_INTERVAL 5 /* hostname lookup failed. Wait N secs for next try */ +#define HOSTNAME_INTERVAL 4 /* hostname lookup failed. Wait N * peer->dns_errors secs for next try */ +#define DNS_ERRORS_CAP 0x3f /* peer->dns_errors is in [0..63] */ /* Step threshold (sec). std ntpd uses 0.128. */ @@ -301,6 +302,7 @@ typedef struct { uint8_t lastpkt_status; uint8_t lastpkt_stratum; uint8_t reachable_bits; + uint8_t dns_errors; /* when to send new query (if p_fd == -1) * or when receive times out (if p_fd >= 0): */ double next_action_time; @@ -802,10 +804,9 @@ resolve_peer_hostname(peer_t *p) p->p_dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa); VERB1 if (strcmp(p->p_hostname, p->p_dotted) != 0) bb_error_msg("'%s' is %s", p->p_hostname, p->p_dotted); - } else { - /* error message is emitted by host2sockaddr() */ - set_next(p, HOSTNAME_INTERVAL); + p->dns_errors = 0; } + p->dns_errors = ((p->dns_errors << 1) | 1) & DNS_ERRORS_CAP; return lsa; } @@ -2358,14 +2359,6 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv) int nfds, timeout; double nextaction; - /* Resolve peer names to IPs, if not resolved yet */ - for (item = G.ntp_peers; item != NULL; item = item->link) { - peer_t *p = (peer_t *) item->data; - - if (p->next_action_time <= G.cur_time && !p->p_lsa) - resolve_peer_hostname(p); - } - /* Nothing between here and poll() blocks for any significant time */ nextaction = G.cur_time + 3600; @@ -2447,13 +2440,38 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv) did_poll: gettime1900d(); /* sets G.cur_time */ if (nfds <= 0) { - if (!bb_got_signal /* poll wasn't interrupted by a signal */ - && G.cur_time - G.last_script_run > 11*60 - ) { + double ct; + + if (bb_got_signal) + break; /* poll was interrupted by a signal */ + + if (G.cur_time - G.last_script_run > 11*60) { /* Useful for updating battery-backed RTC and such */ run_script("periodic", G.last_update_offset); gettime1900d(); /* sets G.cur_time */ } + + /* Resolve peer names to IPs, if not resolved yet. + * We do it only when poll timed out: + * this way, we almost never overlap DNS resolution with + * "request-reply" packet round trip. + */ + ct = G.cur_time; + for (item = G.ntp_peers; item != NULL; item = item->link) { + peer_t *p = (peer_t *) item->data; + if (p->next_action_time <= ct && !p->p_lsa) { + /* This can take up to ~10 sec per each DNS query */ + resolve_peer_hostname(p); + } + } + gettime1900d(); /* sets G.cur_time (needed for set_next()) */ + /* Set next time for those which are still not resolved */ + for (item = G.ntp_peers; item != NULL; item = item->link) { + peer_t *p = (peer_t *) item->data; + if (p->next_action_time <= ct && !p->p_lsa) { + set_next(p, HOSTNAME_INTERVAL * p->dns_errors); + } + } goto check_unsync; } |