From: Nicolas Dichtel Date: Tue, 8 Jun 2021 14:59:51 +0000 (+0200) Subject: vrf: fix maximum MTU X-Git-Tag: v5.15~952^2~72 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=9bb392f62447d73cc7dd7562413a2cd9104c82f8;p=mirror_ubuntu-kernels.git vrf: fix maximum MTU My initial goal was to fix the default MTU, which is set to 65536, ie above the maximum defined in the driver: 65535 (ETH_MAX_MTU). In fact, it's seems more consistent, wrt min_mtu, to set the max_mtu to IP6_MAX_MTU (65535 + sizeof(struct ipv6hdr)) and use it by default. Let's also, for consistency, set the mtu in vrf_setup(). This function calls ether_setup(), which set the mtu to 1500. Thus, the whole mtu config is done in the same function. Before the patch: $ ip link add blue type vrf table 1234 $ ip link list blue 9: blue: mtu 65536 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether fa:f5:27:70:24:2a brd ff:ff:ff:ff:ff:ff $ ip link set dev blue mtu 65535 $ ip link set dev blue mtu 65536 Error: mtu greater than device maximum. Fixes: 5055376a3b44 ("net: vrf: Fix ping failed when vrf mtu is set to 0") CC: Miaohe Lin Signed-off-by: Nicolas Dichtel Reviewed-by: David Ahern Signed-off-by: David S. Miller --- diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 503e2fd7ce51..28a6c4cfe9b8 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -1183,9 +1183,6 @@ static int vrf_dev_init(struct net_device *dev) dev->flags = IFF_MASTER | IFF_NOARP; - /* MTU is irrelevant for VRF device; set to 64k similar to lo */ - dev->mtu = 64 * 1024; - /* similarly, oper state is irrelevant; set to up to avoid confusion */ dev->operstate = IF_OPER_UP; netdev_lockdep_set_classes(dev); @@ -1685,7 +1682,8 @@ static void vrf_setup(struct net_device *dev) * which breaks networking. */ dev->min_mtu = IPV6_MIN_MTU; - dev->max_mtu = ETH_MAX_MTU; + dev->max_mtu = IP6_MAX_MTU; + dev->mtu = dev->max_mtu; } static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],