| Message ID | 1387286409-1783-1-git-send-email-dborkman@redhat.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Tue, 17 Dec 2013 14:20:09 +0100 Daniel Borkmann <dborkman@redhat.com> wrote: > +static int vxlan_change_mtu(struct net_device *dev, int new_mtu) > +{ > + struct net *net = current->nsproxy->net_ns; > + struct vxlan_dev *vxlan = netdev_priv(dev); > + struct vxlan_rdst *dst = &vxlan->default_dst; > + bool is_ipv6 = dst->remote_ip.sa.sa_family == AF_INET6; > + int hroom = is_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM; > + struct net_device *lowerdev; > + > + lowerdev = dev_get_by_index(net, dst->remote_ifindex); > + if (lowerdev == NULL) > + return eth_change_mtu(dev, new_mtu); > + > + if (new_mtu == lowerdev->mtu) > + new_mtu = lowerdev->mtu - hroom; > + if (new_mtu < 68 || new_mtu > lowerdev->mtu - hroom) { > + dev_put(lowerdev); > + return -EINVAL; > + } > + > + dev->mtu = new_mtu; > + > + dev_put(lowerdev); > + return 0; > +} > + The *net should just be devnet(dev). Don't need ref here, called under RTNL. You can't arbitrarly shrink user's requested mtu Minor nit picking: I don't like adding more local flag variables. To me it is clearer. The resulting function is: static int vxlan_change_mtu(struct net_device *dev, int new_mtu) { struct vxlan_dev *vxlan = netdev_priv(dev); int maxmtu; struct net_device *lowerdev; lowerdev = __dev_get_by_index(devnet(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) maxmtu = lowerdev->mtu - VXLAN6_HEADROOM; else maxmtu = lowerdev->mtu - VXLAN_HEADROOM; if (new_mtu < 68 || new_mtu > maxmtu) return -EINVAL; dev->mtu = new_mtu; return 0; } -- 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
On 12/17/2013 06:36 PM, Stephen Hemminger wrote: > On Tue, 17 Dec 2013 14:20:09 +0100 > Daniel Borkmann <dborkman@redhat.com> wrote: > >> +static int vxlan_change_mtu(struct net_device *dev, int new_mtu) >> +{ >> + struct net *net = current->nsproxy->net_ns; >> + struct vxlan_dev *vxlan = netdev_priv(dev); >> + struct vxlan_rdst *dst = &vxlan->default_dst; >> + bool is_ipv6 = dst->remote_ip.sa.sa_family == AF_INET6; >> + int hroom = is_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM; >> + struct net_device *lowerdev; >> + >> + lowerdev = dev_get_by_index(net, dst->remote_ifindex); >> + if (lowerdev == NULL) >> + return eth_change_mtu(dev, new_mtu); >> + >> + if (new_mtu == lowerdev->mtu) >> + new_mtu = lowerdev->mtu - hroom; >> + if (new_mtu < 68 || new_mtu > lowerdev->mtu - hroom) { >> + dev_put(lowerdev); >> + return -EINVAL; >> + } >> + >> + dev->mtu = new_mtu; >> + >> + dev_put(lowerdev); >> + return 0; >> +} >> + > > The *net should just be devnet(dev). > > Don't need ref here, called under RTNL. > > You can't arbitrarly shrink user's requested mtu > > Minor nit picking: I don't like adding more local flag variables. > To me it is clearer. Ok, will send a v2 with your feedback incorporated. Thanks a lot Stephen! > The resulting function is: > > > static int vxlan_change_mtu(struct net_device *dev, int new_mtu) > { > struct vxlan_dev *vxlan = netdev_priv(dev); > int maxmtu; > struct net_device *lowerdev; > > lowerdev = __dev_get_by_index(devnet(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) > maxmtu = lowerdev->mtu - VXLAN6_HEADROOM; > else > maxmtu = lowerdev->mtu - VXLAN_HEADROOM; > > if (new_mtu < 68 || new_mtu > maxmtu) > return -EINVAL; > > dev->mtu = new_mtu; > return 0; > } > > -- 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..b80c22b 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2014,6 +2014,32 @@ static void vxlan_set_multicast_list(struct net_device *dev) { } +static int vxlan_change_mtu(struct net_device *dev, int new_mtu) +{ + struct net *net = current->nsproxy->net_ns; + struct vxlan_dev *vxlan = netdev_priv(dev); + struct vxlan_rdst *dst = &vxlan->default_dst; + bool is_ipv6 = dst->remote_ip.sa.sa_family == AF_INET6; + int hroom = is_ipv6 ? VXLAN6_HEADROOM : VXLAN_HEADROOM; + struct net_device *lowerdev; + + lowerdev = dev_get_by_index(net, dst->remote_ifindex); + if (lowerdev == NULL) + return eth_change_mtu(dev, new_mtu); + + if (new_mtu == lowerdev->mtu) + new_mtu = lowerdev->mtu - hroom; + if (new_mtu < 68 || new_mtu > lowerdev->mtu - hroom) { + dev_put(lowerdev); + return -EINVAL; + } + + dev->mtu = new_mtu; + + dev_put(lowerdev); + return 0; +} + static const struct net_device_ops vxlan_netdev_ops = { .ndo_init = vxlan_init, .ndo_uninit = vxlan_uninit, @@ -2022,7 +2048,7 @@ 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> --- drivers/net/vxlan.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)