ntpd: if peer does not reply anymore, try re-resolving its hostname

function                                             old     new   delta
ntpd_main                                           1053    1130     +77
add_peers                                            166     195     +29

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/networking/ntpd.c b/networking/ntpd.c
index 517806e75..410318979 100644
--- a/networking/ntpd.c
+++ b/networking/ntpd.c
@@ -267,6 +267,7 @@ typedef struct {
 
 typedef struct {
         len_and_sockaddr *p_lsa;
+        char             *p_hostname;
         char             *p_dotted;
         int              p_fd;
         int              datapoint_idx;
@@ -781,11 +782,14 @@ add_peers(const char *s)
                 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;
                 }
         }
 
+        p->p_hostname = xstrdup(s);
         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); */
@@ -2332,6 +2336,21 @@ int ntpd_main(int argc UNUSED_PARAM, char **argv)
                                         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) {
+                                                len_and_sockaddr *lsa = host2sockaddr(p->p_hostname, 123);
+                                                if (lsa) {
+                                                        char *dotted = xmalloc_sockaddr2dotted_noport(&lsa->u.sa);
+                                                        //if (strcmp(dotted, p->p_dotted) != 0)
+                                                        //      bb_error_msg("peer IP changed");
+                                                        free(p->p_lsa);
+                                                        free(p->p_dotted);
+                                                        p->p_lsa = lsa;
+                                                        p->p_dotted = dotted;
+                                                }
+                                        }
+
                                         set_next(p, timeout);
                                 }
                         }