From bec42ef393c0ad64e699a901ab0746d16bfde251 Mon Sep 17 00:00:00 2001 From: Alexey Izbyshev Date: Fri, 24 Feb 2023 23:48:55 +0300 Subject: dns: handle early eof in tcp fallback A zero returned from recvmsg is currently treated as if some data were received, so if a DNS server closes its TCP socket before sending the full answer, __res_msend_rc will spin until the timeout elapses because POLLIN event will be reported on each poll. Fix this by treating an early EOF as an error. --- src/network/res_msend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/network') diff --git a/src/network/res_msend.c b/src/network/res_msend.c index fef7e3a2..2643be22 100644 --- a/src/network/res_msend.c +++ b/src/network/res_msend.c @@ -287,7 +287,7 @@ int __res_msend_rc(int nqueries, const unsigned char *const *queries, }; step_mh(&mh, apos[i]); r = recvmsg(pfd[i].fd, &mh, 0); - if (r < 0) goto out; + if (r <= 0) goto out; apos[i] += r; if (apos[i] < 2) continue; int alen = alen_buf[i][0]*256 + alen_buf[i][1]; -- cgit v1.2.1