diff options
| -rw-r--r-- | ares/ares_getsock.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/ares/ares_getsock.c b/ares/ares_getsock.c index 99419aee2..38b8fefac 100644 --- a/ares/ares_getsock.c +++ b/ares/ares_getsock.c @@ -34,16 +34,18 @@ int ares_getsock(ares_channel channel, ares_socket_t *socks = (ares_socket_t *)s; - /* No queries, no file descriptors. */ - if (ares__is_list_empty(&(channel->all_queries))) - return 0; + /* Are there any active queries? */ + int active_queries = !ares__is_list_empty(&(channel->all_queries)); for (i = 0; (i < channel->nservers) && (sockindex < ARES_GETSOCK_MAXNUM); i++) { server = &channel->servers[i]; - if (server->udp_socket != ARES_SOCKET_BAD) + /* We only need to register interest in UDP sockets if we have + * outstanding queries. + */ + if (active_queries && server->udp_socket != ARES_SOCKET_BAD) { if(sockindex >= numsocks) break; @@ -51,6 +53,10 @@ int ares_getsock(ares_channel channel, bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex); sockindex++; } + /* We always register for TCP events, because we want to know + * when the other side closes the connection, so we don't waste + * time trying to use a broken connection. + */ if (server->tcp_socket != ARES_SOCKET_BAD) { if(sockindex >= numsocks) @@ -58,7 +64,7 @@ int ares_getsock(ares_channel channel, socks[sockindex] = server->tcp_socket; bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex); - if (server->qhead) + if (server->qhead && active_queries) /* then the tcp socket is also writable! */ bitmap |= ARES_GETSOCK_WRITABLE(setbits, sockindex); |