| Message ID | 1387322468-17368-1-git-send-email-dborkman@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 18 Dec 2013 00:21:08 +0100 Daniel Borkmann <dborkman@redhat.com> wrote: > 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 <shahed.shaikh@qlogic.com> > Signed-off-by: Daniel Borkmann <dborkman@redhat.com> This code is good thanks. Acked-by: Stephen Hemminger <stephen@networkplumber.org> P.s: I wonder if notifier handler would be good to handle changes to underlying device MTU on the fly. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Daniel Borkmann <dborkman@redhat.com> Date: Wed, 18 Dec 2013 00:21:08 +0100 > 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 <shahed.shaikh@qlogic.com> > Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Applied, thanks Daniel. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Stephen Hemminger <stephen@networkplumber.org> Date: Tue, 17 Dec 2013 15:40:52 -0800 > P.s: I wonder if notifier handler would be good to handle changes > to underlying device MTU on the fly. I think it would be a good idea. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 58f6a0c..c379c24 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2014,6 +2014,29 @@ 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), 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 +2045,7 @@ 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,
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 <shahed.shaikh@qlogic.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> --- v1->v2: - applied Stephen's feedback v2->v3: - use dst directly in __dev_get_by_index() drivers/net/vxlan.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)