Re: [PATCH net] r8152: drop the tx packet with invalid length

From: Eric Dumazet
Date: Fri Dec 19 2014 - 13:14:05 EST


On Fri, 2014-12-19 at 09:36 -0800, Eric Dumazet wrote:
> On Fri, 2014-12-19 at 06:42 +0000, Hayes Wang wrote:
>
> > Excuse me. I try to implement ndo_gso_check() with kernel 3.18.
> > However, I still get packets with gso and their skb lengths are more
> > than the acceptable one. Do I miss something?
> >
> > +static bool rtl8152_gso_check(struct sk_buff *skb, struct net_device *dev)
> > +{
> > + if ((skb->len + sizeof(struct tx_desc)) > agg_buf_sz)
> > + return false;
> > +
> > + return true;
> > +}
> >
> > @@ -5861,6 +5876,9 @@ static const struct net_device_ops rtl8152_netdev_ops = {
> > .ndo_set_mac_address = rtl8152_set_mac_address,
> > .ndo_change_mtu = rtl8152_change_mtu,
> > .ndo_validate_addr = eth_validate_addr,
> > + .ndo_gso_check = rtl8152_gso_check,
> > };
>
> You are right, it seems ndo_gso_check() is buggy at this moment.
>
> Presumably this method should alter %features so that we really segment
> the packets in software.
>
> features &= ~NETIF_F_GSO_MASK;

Could you try following patch ?

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 7df221788cd4..0346bcfe72a5 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -314,7 +314,7 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
*/
if (q->flags & IFF_VNET_HDR)
features |= vlan->tap_features;
- if (netif_needs_gso(dev, skb, features)) {
+ if (netif_needs_gso(dev, skb, &features)) {
struct sk_buff *segs = __skb_gso_segment(skb, features, false);

if (IS_ERR(segs))
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 22bcb4e12e2a..9cacabaea175 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -578,6 +578,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
unsigned long flags;
struct netfront_queue *queue = NULL;
unsigned int num_queues = dev->real_num_tx_queues;
+ netdev_features_t features;
u16 queue_index;

/* Drop the packet if no queues are set up */
@@ -611,9 +612,10 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)

spin_lock_irqsave(&queue->tx_lock, flags);

+ features = netif_skb_features(skb);
if (unlikely(!netif_carrier_ok(dev) ||
(slots > 1 && !xennet_can_sg(dev)) ||
- netif_needs_gso(dev, skb, netif_skb_features(skb)))) {
+ netif_needs_gso(dev, skb, &features))) {
spin_unlock_irqrestore(&queue->tx_lock, flags);
goto drop;
}
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c31f74d76ebd..fb1f8c900df9 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3608,13 +3608,19 @@ static inline bool skb_gso_ok(struct sk_buff *skb, netdev_features_t features)
}

static inline bool netif_needs_gso(struct net_device *dev, struct sk_buff *skb,
- netdev_features_t features)
+ netdev_features_t *features)
{
- return skb_is_gso(skb) && (!skb_gso_ok(skb, features) ||
- (dev->netdev_ops->ndo_gso_check &&
- !dev->netdev_ops->ndo_gso_check(skb, dev)) ||
- unlikely((skb->ip_summed != CHECKSUM_PARTIAL) &&
- (skb->ip_summed != CHECKSUM_UNNECESSARY)));
+ if (!skb_is_gso(skb))
+ return false;
+ if (!skb_gso_ok(skb, *features))
+ return true;
+ if (dev->netdev_ops->ndo_gso_check &&
+ !dev->netdev_ops->ndo_gso_check(skb, dev)) {
+ *features &= ~NETIF_F_GSO_MASK;
+ return true;
+ }
+ return skb->ip_summed != CHECKSUM_PARTIAL &&
+ skb->ip_summed != CHECKSUM_UNNECESSARY;
}

static inline void netif_set_gso_max_size(struct net_device *dev,
diff --git a/net/core/dev.c b/net/core/dev.c
index f411c28d0a66..b61c26b45bb7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2668,7 +2668,7 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device
if (skb->encapsulation)
features &= dev->hw_enc_features;

- if (netif_needs_gso(dev, skb, features)) {
+ if (netif_needs_gso(dev, skb, &features)) {
struct sk_buff *segs;

segs = skb_gso_segment(skb, features);


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