[libvirt] [PATCH] network: don't use dhcp-authoritative on static networks

[Martin Wilck]

"Static" DHCP networks are those where no dynamic DHCP range is
defined, only a list of host entries is used to serve permanent
IP addresses. On such networks, we don't want dnsmasq to reply
to other requests than those statically defined. But
"dhcp-authoritative" will cause dnsmasq to do just that.
Therefore we can't use "dhcp-authoritative" for static networks.

Fixes: 4ac20b3ae "network: add dnsmasq option 'dhcp-authoritative'"
Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 src/network/bridge_driver.c                             | 9 ++++++++-
 tests/networkxml2confdata/dhcp6host-routed-network.conf | 1 -
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index ae1589d8c..17c6f3a0f 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1355,7 +1355,14 @@ networkDnsmasqConfContents(virNetworkObjPtr network,
         if (VIR_SOCKET_ADDR_IS_FAMILY(&ipdef->address, AF_INET)) {
             if (ipdef->nranges || ipdef->nhosts) {
                 virBufferAddLit(&configbuf, "dhcp-no-override\n");
-                virBufferAddLit(&configbuf, "dhcp-authoritative\n");
+		/*
+                 * Use "dhcp-authoritative" only for dynamic DHCP.
+                 * In a static-only network, it would cause dnsmasq
+                 * to reply to requests from other hosts than those
+                 * statically defined.
+                 */
+		if (ipdef->nranges || !ipdef->nhosts)
+                    virBufferAddLit(&configbuf, "dhcp-authoritative\n");
             }
 
             if (ipdef->tftproot) {
diff --git a/tests/networkxml2confdata/dhcp6host-routed-network.conf b/tests/networkxml2confdata/dhcp6host-routed-network.conf
index 87a149880..5728ee430 100644
--- a/tests/networkxml2confdata/dhcp6host-routed-network.conf
+++ b/tests/networkxml2confdata/dhcp6host-routed-network.conf
@@ -10,7 +10,6 @@ bind-dynamic
 interface=virbr1
 dhcp-range=192.168.122.1,static
 dhcp-no-override
-dhcp-authoritative
 dhcp-range=2001:db8:ac10:fd01::1,static,64
 dhcp-hostsfile=/var/lib/libvirt/dnsmasq/local.hostsfile
 addn-hosts=/var/lib/libvirt/dnsmasq/local.addnhosts
-- 
2.11.0