network: set mtu as a DHCP option when specified

This adds an additional directive to the dnsmasq configuration file that
notifies clients via dhcp about the link's MTU. Guests can then choose
adjust their link accordingly.

Signed-off-by: Casey Callendrello <cdc@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>

diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 20a0f65e65cc85c252fcb01fb4e2410291d27dab..a9674ef6c2c640a5c689118b546fca4747debf04 100644 (file)
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1410,6 +1410,10 @@ networkDnsmasqConfContents(virNetworkObjPtr obj,
                           dctx->addnhostsfile->path);
     }
 
+    /* Configure DHCP to tell clients about the MTU. */
+    if (def->mtu > 0)
+        virBufferAsprintf(&configbuf, "dhcp-option=option:mtu,%d\n", def->mtu);
+
     /* Are we doing RA instead of radvd? */
     if (DNSMASQ_RA_SUPPORT(caps)) {
         if (ipv6def) {

diff --git a/tests/networkxml2confdata/nat-network-mtu.conf b/tests/networkxml2confdata/nat-network-mtu.conf
new file mode 100644 (file)
index 0000000..91b574b
--- /dev/null
+++ b/tests/networkxml2confdata/nat-network-mtu.conf
@@ -0,0 +1,19 @@
+##WARNING:  THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
+##OVERWRITTEN AND LOST.  Changes to this configuration should be made using:
+##    virsh net-edit default
+## or other application using the libvirt API.
+##
+## dnsmasq conf file created by libvirt
+strict-order
+except-interface=lo
+bind-dynamic
+interface=virbr0
+dhcp-range=192.168.122.2,192.168.122.254
+dhcp-no-override
+dhcp-authoritative
+dhcp-lease-max=253
+dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile
+addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts
+dhcp-option=option:mtu,7000
+dhcp-range=2001:db8:ac10:fe01::1,ra-only
+dhcp-range=2001:db8:ac10:fd01::1,ra-only

diff --git a/tests/networkxml2confdata/nat-network-mtu.xml b/tests/networkxml2confdata/nat-network-mtu.xml
new file mode 100644 (file)
index 0000000..87b214e
--- /dev/null
+++ b/tests/networkxml2confdata/nat-network-mtu.xml
@@ -0,0 +1,22 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <forward dev='eth1' mode='nat'/>
+  <bridge name='virbr0' stp='on' delay='0'/>
+  <mtu size='7000'/>
+  <ip address='192.168.122.1' netmask='255.255.255.0'>
+    <dhcp>
+      <range start='192.168.122.2' end='192.168.122.254'/>
+      <host mac='00:16:3e:77:e2:ed' name='a.example.com' ip='192.168.122.10'/>
+      <host mac='00:16:3e:3e:a9:1a' name='b.example.com' ip='192.168.122.11'/>
+    </dhcp>
+  </ip>
+  <ip family='ipv4' address='192.168.123.1' netmask='255.255.255.0'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fe01::1' prefix='64'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
+  </ip>
+  <ip family='ipv4' address='10.24.10.1'>
+  </ip>
+</network>

diff --git a/tests/networkxml2conftest.c b/tests/networkxml2conftest.c
index c362149c296bedc6af0da6719fbd10958d41b56c..bf9675838d792f32eceb3876a15a200d8220d567 100644 (file)
--- a/tests/networkxml2conftest.c
+++ b/tests/networkxml2conftest.c
@@ -136,6 +136,7 @@ mymain(void)
     DO_TEST("nat-network-dns-forwarders", full);
     DO_TEST("nat-network-dns-forwarder-no-resolv", full);
     DO_TEST("nat-network-dns-local-domain", full);
+    DO_TEST("nat-network-mtu", dhcpv6);
     DO_TEST("dhcp6-network", dhcpv6);
     DO_TEST("dhcp6-nat-network", dhcpv6);
     DO_TEST("dhcp6host-routed-network", dhcpv6);

diff --git a/tests/networkxml2xmlin/nat-network-mtu.xml b/tests/networkxml2xmlin/nat-network-mtu.xml
new file mode 100644 (file)
index 0000000..07d0d9f
--- /dev/null
+++ b/tests/networkxml2xmlin/nat-network-mtu.xml
@@ -0,0 +1,22 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <bridge name="virbr0"/>
+  <mtu size='7000'/>
+  <forward mode="nat" dev="eth1"/>
+  <ip address="192.168.122.1" netmask="255.255.255.0">
+    <dhcp>
+      <range start="192.168.122.2" end="192.168.122.254"/>
+      <host mac="00:16:3e:77:e2:ed" name="a.example.com" ip="192.168.122.10"/>
+      <host mac="00:16:3e:3e:a9:1a" name="b.example.com" ip="192.168.122.11"/>
+    </dhcp>
+  </ip>
+  <ip family="ipv4" address="192.168.123.1" netmask="255.255.255.0">
+  </ip>
+  <ip family="ipv6" address="2001:db8:ac10:fe01::1" prefix="64">
+  </ip>
+  <ip family="ipv6" address="2001:db8:ac10:fd01::1" prefix="64">
+  </ip>
+  <ip family="ipv4" address="10.24.10.1">
+  </ip>
+</network>

diff --git a/tests/networkxml2xmlout/nat-network-mtu.xml b/tests/networkxml2xmlout/nat-network-mtu.xml
new file mode 100644 (file)
index 0000000..715bc1b
--- /dev/null
+++ b/tests/networkxml2xmlout/nat-network-mtu.xml
@@ -0,0 +1,24 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <forward dev='eth1' mode='nat'>
+    <interface dev='eth1'/>
+  </forward>
+  <bridge name='virbr0' stp='on' delay='0'/>
+  <mtu size='7000'/>
+  <ip address='192.168.122.1' netmask='255.255.255.0'>
+    <dhcp>
+      <range start='192.168.122.2' end='192.168.122.254'/>
+      <host mac='00:16:3e:77:e2:ed' name='a.example.com' ip='192.168.122.10'/>
+      <host mac='00:16:3e:3e:a9:1a' name='b.example.com' ip='192.168.122.11'/>
+    </dhcp>
+  </ip>
+  <ip family='ipv4' address='192.168.123.1' netmask='255.255.255.0'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fe01::1' prefix='64'>
+  </ip>
+  <ip family='ipv6' address='2001:db8:ac10:fd01::1' prefix='64'>
+  </ip>
+  <ip family='ipv4' address='10.24.10.1'>
+  </ip>
+</network>

diff --git a/tests/networkxml2xmltest.c b/tests/networkxml2xmltest.c
index 4e4c7d20a67b17c1b4a69bc3fe034e70740a3f5c..b19a365ff48e50bb2fdf15901dfa65b9342366f7 100644 (file)
--- a/tests/networkxml2xmltest.c
+++ b/tests/networkxml2xmltest.c
@@ -141,6 +141,7 @@ mymain(void)
     DO_TEST("nat-network-dns-forwarder-no-resolv");
     DO_TEST("nat-network-forward-nat-address");
     DO_TEST("nat-network-forward-nat-no-address");
+    DO_TEST("nat-network-mtu");
     DO_TEST("8021Qbh-net");
     DO_TEST("direct-net");
     DO_TEST("host-bridge-net");