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From 838188511cb2085d8980956b270cc68ed9911102 Mon Sep 17 00:00:00 2001
From: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
Date: Thu, 4 Aug 2016 12:26:56 +0200
Subject: [PATCH 11/12] ntpd: postpone hostname resolution if fails on startup
Signed-off-by: Kaarle Ritvanen <kaarle.ritvanen@datakunkku.fi>
---
networking/ntpd.c | 130 +++++++++++++++++++++++++++---------------------------
1 file changed, 64 insertions(+), 66 deletions(-)
diff --git a/networking/ntpd.c b/networking/ntpd.c
index b7fa5dce9..c6d07adac 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -155,6 +155,7 @@
#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 4 /* hostname lookup failed. Wait N secs for next try */
/* Step threshold (sec). std ntpd uses 0.128.
*/
@@ -293,6 +294,7 @@ typedef struct {
typedef struct {
len_and_sockaddr *p_lsa;
+ char *p_hostname;
char *p_dotted;
int p_fd;
int datapoint_idx;
@@ -318,7 +320,6 @@ typedef struct {
datapoint_t filter_datapoint[NUM_DATAPOINTS];
/* last sent packet: */
msg_t p_xmt_msg;
- char p_hostname[1];
} peer_t;
@@ -791,27 +792,17 @@ reset_peer_stats(peer_t *p, double offset)
}
static void
-resolve_peer_hostname(peer_t *p, int loop_on_fail)
-{
- len_and_sockaddr *lsa;
-
- again:
- lsa = host2sockaddr(p->p_hostname, 123);
- if (!lsa) {
- /* error message already emitted by host2sockaddr() */
- if (!loop_on_fail)
- return;
-//FIXME: do this to avoid infinite looping on typo in a hostname?
-//well... in which case, what is a good value for loop_on_fail?
- //if (--loop_on_fail == 0)
- // xfunc_die();
- sleep(5);
- goto again;
+resolve_peer_hostname(peer_t *p) {
+ len_and_sockaddr *lsa = host2sockaddr(p->p_hostname, 123);
+ if (lsa) {
+ if (p->p_lsa) {
+ free(p->p_lsa);
+ free(p->p_dotted);
+ }
+ p->p_lsa = lsa;
+ p->p_dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
}
- free(p->p_lsa);
- free(p->p_dotted);
- p->p_lsa = lsa;
- p->p_dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
+ set_next(p, lsa ? 0 : HOSTNAME_INTERVAL);
}
static void
@@ -820,28 +811,29 @@ add_peers(const char *s)
llist_t *item;
peer_t *p;
- p = xzalloc(sizeof(*p) + strlen(s));
- strcpy(p->p_hostname, s);
- resolve_peer_hostname(p, /*loop_on_fail=*/ 1);
+ p = xzalloc(sizeof(*p));
+ p->p_hostname = xstrdup(s);
+ resolve_peer_hostname(p);
/* Names like N.<country2chars>.pool.ntp.org are randomly resolved
* to a pool of machines. Sometimes different N's resolve to the same IP.
* It is not useful to have two peers with same IP. We skip duplicates.
*/
- for (item = G.ntp_peers; item != NULL; item = item->link) {
- peer_t *pp = (peer_t *) item->data;
- if (strcmp(p->p_dotted, pp->p_dotted) == 0) {
- bb_error_msg("duplicate peer %s (%s)", s, p->p_dotted);
- free(p->p_lsa);
- free(p->p_dotted);
- free(p);
- return;
+ if (p->p_lsa)
+ for (item = G.ntp_peers; item != NULL; item = item->link) {
+ peer_t *pp = (peer_t *) item->data;
+ if (pp->p_lsa && strcmp(p->p_dotted, pp->p_dotted) == 0) {
+ bb_error_msg("duplicate peer %s (%s)", s, p->p_dotted);
+ free(p->p_hostname);
+ free(p->p_lsa);
+ free(p->p_dotted);
+ free(p);
+ return;
+ }
}
- }
p->p_fd = -1;
p->p_xmt_msg.m_status = MODE_CLIENT | (NTP_VERSION << 3);
- p->next_action_time = G.cur_time; /* = set_next(p, 0); */
reset_peer_stats(p, STEP_THRESHOLD);
llist_add_to(&G.ntp_peers, p);
@@ -2378,44 +2370,50 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
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) {
- if (p->p_fd == -1) {
- /* Time to send new req */
- if (--cnt == 0) {
- VERB4 bb_error_msg("disabling burst mode");
- G.polladj_count = 0;
- G.poll_exp = MINPOLL;
+ if (p->p_lsa) {
+
+ if (p->next_action_time <= G.cur_time) {
+ if (p->p_fd == -1) {
+ /* Time to send new req */
+ if (--cnt == 0) {
+ VERB4 bb_error_msg("disabling burst mode");
+ G.polladj_count = 0;
+ G.poll_exp = MINPOLL;
+ }
+ send_query_to_peer(p);
+ } else {
+ /* Timed out waiting for reply */
+ close(p->p_fd);
+ p->p_fd = -1;
+ /* If poll interval is small, increase it */
+ if (G.poll_exp < BIGPOLL)
+ adjust_poll(MINPOLL);
+ timeout = poll_interval(NOREPLY_INTERVAL);
+ bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
+ p->p_dotted, p->reachable_bits, timeout);
+
+ /* What if don't see it because it changed its IP? */
+ if (p->reachable_bits == 0)
+ resolve_peer_hostname(p);
+
+ set_next(p, timeout);
}
- send_query_to_peer(p);
- } else {
- /* Timed out waiting for reply */
- close(p->p_fd);
- p->p_fd = -1;
- /* If poll interval is small, increase it */
- if (G.poll_exp < BIGPOLL)
- adjust_poll(MINPOLL);
- timeout = poll_interval(NOREPLY_INTERVAL);
- bb_error_msg("timed out waiting for %s, reach 0x%02x, next query in %us",
- p->p_dotted, p->reachable_bits, timeout);
-
- /* What if don't see it because it changed its IP? */
- if (p->reachable_bits == 0)
- resolve_peer_hostname(p, /*loop_on_fail=*/ 0);
-
- set_next(p, timeout);
}
- }
+
+ if (p->p_fd >= 0) {
+ /* Wait for reply from this peer */
+ pfd[i].fd = p->p_fd;
+ pfd[i].events = POLLIN;
+ idx2peer[i] = p;
+ i++;
+ }
+
+ } else
+ resolve_peer_hostname(p);
if (p->next_action_time < nextaction)
nextaction = p->next_action_time;
- if (p->p_fd >= 0) {
- /* Wait for reply from this peer */
- pfd[i].fd = p->p_fd;
- pfd[i].events = POLLIN;
- idx2peer[i] = p;
- i++;
- }
}
timeout = nextaction - G.cur_time;
--
2.11.0
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