Fix bug which caused dnsmasq to become unresponsive when an interface goes.
diff --git a/CHANGELOG b/CHANGELOG
index 00f0480..35093ad 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -33,6 +33,10 @@
Fix bug when resulted in NXDOMAIN answers instead of NODATA in
some circumstances.
+
+ Fix bug which caused dnsmasq to become unresponsive if it
+ failed to send packets due to a network interface disappearing.
+ Thanks to Niels Peen for spotting this.
version 2.71
diff --git a/src/util.c b/src/util.c
index df751c7..a729f33 100644
--- a/src/util.c
+++ b/src/util.c
@@ -570,18 +570,28 @@
int retry_send(void)
{
- struct timespec waiter;
+ /* Linux kernels can return EAGAIN in perpetuity when calling
+ sendmsg() and the relevant interface has gone. Here we loop
+ retrying in EAGAIN for 1 second max, to avoid this hanging
+ dnsmasq. */
+
+ static int retries = 0;
+ struct timespec waiter;
+
if (errno == EAGAIN || errno == EWOULDBLOCK)
{
waiter.tv_sec = 0;
waiter.tv_nsec = 10000;
nanosleep(&waiter, NULL);
- return 1;
+ if (retries++ < 1000)
+ return 1;
}
+
+ retries = 0;
if (errno == EINTR)
return 1;
-
+
return 0;
}
