Increase the TCP timeout allowance from 1 second to 3

When starting a new TCP query, the initial SRTT estimate includes time for the kernel to resend SYN if necessary. At one second, the margin was not always sufficient; this commit increases it to three.
2021-10-13 22:34:19 -07:00
1 changed files with 2 additions and 2 deletions
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -1947,12 +1947,12 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
 	srtt = addrinfo->srtt;

 	/*
-	 * Allow an additional second for the kernel to resend the SYN
+	 * Allow an additional 3 seconds for the kernel to resend the SYN
 	 * (or SYN without ECN in the case of stupid firewalls blocking
 	 * ECN negotiation) over the current RTT estimate.
 	 */
 	if ((options & DNS_FETCHOPT_TCP) != 0) {
-		srtt += US_PER_SEC;
+		srtt += 3 * US_PER_SEC;
 	}

 	/*