From 682be115057f0dffbdd73dac93cb9dc676e279c0 Mon Sep 17 00:00:00 2001 From: Casey Callendrello Date: Tue, 11 Dec 2018 17:05:43 +0100 Subject: [PATCH] network: set mtu as a DHCP option when specified MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Ján Tomko Signed-off-by: Ján Tomko --- src/network/bridge_driver.c | 4 ++++ .../networkxml2confdata/nat-network-mtu.conf | 19 +++++++++++++++ tests/networkxml2confdata/nat-network-mtu.xml | 22 +++++++++++++++++ tests/networkxml2conftest.c | 1 + tests/networkxml2xmlin/nat-network-mtu.xml | 22 +++++++++++++++++ tests/networkxml2xmlout/nat-network-mtu.xml | 24 +++++++++++++++++++ tests/networkxml2xmltest.c | 1 + 7 files changed, 93 insertions(+) create mode 100644 tests/networkxml2confdata/nat-network-mtu.conf create mode 100644 tests/networkxml2confdata/nat-network-mtu.xml create mode 100644 tests/networkxml2xmlin/nat-network-mtu.xml create mode 100644 tests/networkxml2xmlout/nat-network-mtu.xml diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 20a0f65e65..a9674ef6c2 100644 --- 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 index 0000000000..91b574b964 --- /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 index 0000000000..87b214e95c --- /dev/null +++ b/tests/networkxml2confdata/nat-network-mtu.xml @@ -0,0 +1,22 @@ + + default + 81ff0d90-c91e-6742-64da-4a736edb9a9b + + + + + + + + + + + + + + + + + + + diff --git a/tests/networkxml2conftest.c b/tests/networkxml2conftest.c index c362149c29..bf9675838d 100644 --- 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 index 0000000000..07d0d9f22d --- /dev/null +++ b/tests/networkxml2xmlin/nat-network-mtu.xml @@ -0,0 +1,22 @@ + + default + 81ff0d90-c91e-6742-64da-4a736edb9a9b + + + + + + + + + + + + + + + + + + + diff --git a/tests/networkxml2xmlout/nat-network-mtu.xml b/tests/networkxml2xmlout/nat-network-mtu.xml new file mode 100644 index 0000000000..715bc1b505 --- /dev/null +++ b/tests/networkxml2xmlout/nat-network-mtu.xml @@ -0,0 +1,24 @@ + + default + 81ff0d90-c91e-6742-64da-4a736edb9a9b + + + + + + + + + + + + + + + + + + + + + diff --git a/tests/networkxml2xmltest.c b/tests/networkxml2xmltest.c index 4e4c7d20a6..b19a365ff4 100644 --- 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");