From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: [PATCH v2 net-next] net: vxlan: use custom ndo_change_mtu handler Date: Tue, 17 Dec 2013 21:37:40 +0100 Message-ID: <1387312660-3467-1-git-send-email-dborkman@redhat.com> Cc: shahed.shaikh@qlogic.com, stephen@networkplumber.org, netdev@vger.kernel.org To: davem@davemloft.net Return-path: Received: from mx1.redhat.com ([209.132.183.28]:20913 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753754Ab3LQUhp (ORCPT ); Tue, 17 Dec 2013 15:37:45 -0500 Sender: netdev-owner@vger.kernel.org List-ID: When adding a new vxlan device to an "underlying carrier" (here: dst->remote_ifindex), the MTU size assigned to the vxlan device is the MTU at setup time of the carrier - needed headroom, when adding a vxlan device w/o explicit carrier, then it defaults to 1500. In case of an explicit carrier that supports jumbo frames, we currently cannot change vxlan MTU via ip(8) to > 1500 in post-setup time, as vxlan driver uses eth_change_mtu() as default method for manually setting MTU. Hence, use a custom implementation that only falls back to eth_change_mtu() in case we didn't use a dev parameter on device setup time, and otherwise allow a max MTU setting of the carrier incl. adjustment for headroom. Reported-by: Shahed Shaikh Signed-off-by: Daniel Borkmann --- v1->v2: - applied Stephen's feedback drivers/net/vxlan.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 58f6a0c..72466e9 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2014,6 +2014,30 @@ static void vxlan_set_multicast_list(struct net_device *dev) { } +static int vxlan_change_mtu(struct net_device *dev, int new_mtu) +{ + struct vxlan_dev *vxlan = netdev_priv(dev); + struct vxlan_rdst *dst = &vxlan->default_dst; + struct net_device *lowerdev; + int max_mtu; + + lowerdev = __dev_get_by_index(dev_net(dev), + vxlan->default_dst.remote_ifindex); + if (lowerdev == NULL) + return eth_change_mtu(dev, new_mtu); + + if (dst->remote_ip.sa.sa_family == AF_INET6) + max_mtu = lowerdev->mtu - VXLAN6_HEADROOM; + else + max_mtu = lowerdev->mtu - VXLAN_HEADROOM; + + if (new_mtu < 68 || new_mtu > max_mtu) + return -EINVAL; + + dev->mtu = new_mtu; + return 0; +} + static const struct net_device_ops vxlan_netdev_ops = { .ndo_init = vxlan_init, .ndo_uninit = vxlan_uninit, @@ -2022,7 +2046,7 @@ static const struct net_device_ops vxlan_netdev_ops = { .ndo_start_xmit = vxlan_xmit, .ndo_get_stats64 = ip_tunnel_get_stats64, .ndo_set_rx_mode = vxlan_set_multicast_list, - .ndo_change_mtu = eth_change_mtu, + .ndo_change_mtu = vxlan_change_mtu, .ndo_validate_addr = eth_validate_addr, .ndo_set_mac_address = eth_mac_addr, .ndo_fdb_add = vxlan_fdb_add, -- 1.8.3.1