Re: [libvirt] [PATCH] 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(a)redhat.com&gt; --- src/network/bridge_driver.c | 7 ++++++ .../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, 96 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 4bbc4f5a6d..81edf72493 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -1506,6 +1506,13 @@ 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) {