Reserve extra 4 bytes on real_dev in addition to the length notified
from upper device.
In 802.1ad mode, set enc_hdr_len to 4 bytes by default, since it is
likely to send already tagged frame.
Signed-off-by: Toshiaki Makita <makita.toshi...@lab.ntt.co.jp>
---
net/8021q/vlan.c | 16 ++++++++++++++--
net/8021q/vlan_dev.c | 48 +++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 57 insertions(+), 7 deletions(-)
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index d2cd9de..bbafc5c 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -355,6 +355,7 @@ static int vlan_device_event(struct notifier_block *unused,
unsigned long event,
struct net_device *vlandev;
struct vlan_dev_priv *vlan;
bool last = false;
+ int dev_max_frame;
LIST_HEAD(list);
if (is_vlan_dev(dev)) {
@@ -399,11 +400,22 @@ static int vlan_device_event(struct notifier_block
*unused, unsigned long event,
break;
case NETDEV_CHANGEMTU:
+ dev_max_frame = dev->mtu + dev->enc_hdr_len;
vlan_group_for_each_dev(grp, i, vlandev) {
- if (vlandev->mtu <= dev->mtu)
+ int enc_hdr_len = vlandev->enc_hdr_len + VLAN_HLEN;
+
+ if (vlandev->mtu <= dev->mtu &&
+ vlandev->mtu + enc_hdr_len <= dev_max_frame)
continue;
- dev_set_mtu(vlandev, dev->mtu);
+ if (vlandev->mtu > dev->mtu) {
+ dev_set_mtu(vlandev, dev->mtu);
+ } else {
+ int mtu_room = dev->mtu - vlandev->mtu;
+
+ dev_set_enc_hdr_len(dev,
+ enc_hdr_len - mtu_room);
+ }
}
break;
diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index fded865..ac377cf 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -143,17 +143,35 @@ static netdev_tx_t vlan_dev_hard_start_xmit(struct
sk_buff *skb,
return ret;
}
+static int vlan_dev_enc_hdr_len(struct net_device *dev, int new_len)
+{
+ struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+ int mtu_room = real_dev->mtu - dev->mtu;
+
+ new_len += VLAN_HLEN;
+ if (new_len > mtu_room)
+ return dev_set_enc_hdr_len(real_dev, new_len - mtu_room);
+
+ return 0;
+}
+
static int vlan_dev_change_mtu(struct net_device *dev, int new_mtu)
{
- /* TODO: gotta make sure the underlying layer can handle it,
- * maybe an IFF_VLAN_CAPABLE flag for devices?
- */
- if (vlan_dev_priv(dev)->real_dev->mtu < new_mtu)
+ struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+ int orig_mtu;
+ int err;
+
+ if (real_dev->mtu < new_mtu)
return -ERANGE;
+ orig_mtu = dev->mtu;
dev->mtu = new_mtu;
- return 0;
+ err = vlan_dev_enc_hdr_len(dev, dev->enc_hdr_len);
+ if (err)
+ dev->mtu = orig_mtu;
+
+ return err;
}
void vlan_dev_set_ingress_priority(const struct net_device *dev,
@@ -532,6 +550,8 @@ static const struct net_device_ops vlan_netdev_ops;
static int vlan_dev_init(struct net_device *dev)
{
struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+ int enc_hdr_len;
+ int err;
netif_carrier_off(dev);
@@ -583,6 +603,23 @@ static int vlan_dev_init(struct net_device *dev)
vlan_dev_set_lockdep_class(dev, vlan_dev_get_lock_subclass(dev));
+ if (vlan_dev_priv(dev)->vlan_proto == htons(ETH_P_8021AD))
+ dev->enc_hdr_len = VLAN_HLEN;
+
+ enc_hdr_len = dev->enc_hdr_len + VLAN_HLEN;
+ err = dev_set_enc_hdr_len(real_dev, enc_hdr_len);
+ if (err) {
+ int new_mtu = real_dev->mtu + real_dev->enc_hdr_len -
+ enc_hdr_len;
+
+ if (new_mtu < 0)
+ return -ENOSPC;
+
+ netdev_warn(dev, "Failed to expand encap header room to %d on
real device. Decrease MTU to %d on vlan device.\n",
+ enc_hdr_len, new_mtu);
+ dev->mtu = new_mtu;
+ }
+
vlan_dev_priv(dev)->vlan_pcpu_stats = netdev_alloc_pcpu_stats(struct
vlan_pcpu_stats);
if (!vlan_dev_priv(dev)->vlan_pcpu_stats)
return -ENOMEM;
@@ -776,6 +813,7 @@ static const struct net_device_ops vlan_netdev_ops = {
.ndo_fix_features = vlan_dev_fix_features,
.ndo_get_lock_subclass = vlan_dev_get_lock_subclass,
.ndo_get_iflink = vlan_dev_get_iflink,
+ .ndo_enc_hdr_len = vlan_dev_enc_hdr_len,
};
static void vlan_dev_free(struct net_device *dev)
--
1.8.1.2
--
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