From adc88ca203bbb602cc9a1726669526fa7b3723ef Mon Sep 17 00:00:00 2001 From: Jason Glasgow Date: Wed, 30 Nov 2011 15:23:44 -0500 Subject: [PATCH] multi: handle timeouts on DNS servers by checking for new sockets If the first name server is not available, the multi interface does not invoke the socket_cb when the DNS request to the first name server timesout. Ensure that the list of sockets are always updated after calling Curl_resolver_is_resolved. This bug can be reproduced if Curl is complied with --enable_ares and your code uses the multi socket interfaces and the CURLMOPT_SOCKETFUNCTION option. To test try: iptables -I INPUT \ -s $(sed -n -e '/name/{s/.* //p;q}' /etc/resolv.conf)/32 \ -j REJECT and then run a program which uses the multi-interface. --- lib/asyn-ares.c | 9 +++++---- lib/multi.c | 13 ++++++++----- 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/lib/asyn-ares.c b/lib/asyn-ares.c index 7c2c372..0b45484 100644 --- a/lib/asyn-ares.c +++ b/lib/asyn-ares.c @@ -227,18 +227,19 @@ int Curl_resolver_getsock(struct connectdata *conn, struct timeval maxtime; struct timeval timebuf; struct timeval *timeout; + long milli; int max = ares_getsock((ares_channel)conn->data->state.resolver, (ares_socket_t *)socks, numsocks); - maxtime.tv_sec = CURL_TIMEOUT_RESOLVE; maxtime.tv_usec = 0; timeout = ares_timeout((ares_channel)conn->data->state.resolver, &maxtime, &timebuf); - - Curl_expire(conn->data, - (timeout->tv_sec * 1000) + (timeout->tv_usec/1000)); + milli = (timeout->tv_sec * 1000) + (timeout->tv_usec/1000); + if(milli == 0) + milli += 10; + Curl_expire(conn->data, milli); return max; } diff --git a/lib/multi.c b/lib/multi.c index ae70851..3059e49 100644 --- a/lib/multi.c +++ b/lib/multi.c @@ -1085,12 +1085,15 @@ static CURLMcode multi_runsingle(struct Curl_multi *multi, /* check if we have the name resolved by now */ easy->result = Curl_resolver_is_resolved(easy->easy_conn, &dns); - if(dns) { - /* Update sockets here. Mainly because the socket(s) may have been - closed and the application thus needs to be told, even if it is - likely that the same socket(s) will again be used further down. */ - singlesocket(multi, easy); + /* Update sockets here, because the socket(s) may have been + closed and the application thus needs to be told, even if it + is likely that the same socket(s) will again be used further + down. If the name has not yet been resolved, it is likely + that new sockets have been opened in an attempt to contact + another resolver. */ + singlesocket(multi, easy); + if(dns) { /* Perform the next step in the connection phase, and then move on to the WAITCONNECT state */ easy->result = Curl_async_resolved(easy->easy_conn, -- 2.7.4