[PATCH 1/2] veth: Fix carrier detect

[PATCH 1/2] veth: Fix carrier detect

[Eric W. Biederman]

The current implementation of carrier detect in veth is broken.
It reports the link is down until both sides of the veth pair
are administatively up and then forever after it reports link up.

So fix veth so that it only reports link up when both interfaces
of the pair are administratively up.

Signed-off-by: Eric Biederman <ebiederm@aristanetworks.com>
---
 drivers/net/veth.c |   51 +++++++++++----------------------------------------
 1 files changed, 11 insertions(+), 40 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 108bbbe..124fe75 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -239,6 +239,16 @@ static int veth_open(struct net_device *dev)
 	return 0;
 }
 
+static int veth_close(struct net_device *dev)
+{
+	struct veth_priv *priv = netdev_priv(dev);
+
+	netif_carrier_off(dev);
+	netif_carrier_off(priv->peer);
+
+	return 0;
+}
+
 static int veth_dev_init(struct net_device *dev)
 {
 	struct veth_net_stats *stats;
@@ -265,6 +275,7 @@ static void veth_dev_free(struct net_device *dev)
 static const struct net_device_ops veth_netdev_ops = {
 	.ndo_init            = veth_dev_init,
 	.ndo_open            = veth_open,
+	.ndo_stop            = veth_close,
 	.ndo_start_xmit      = veth_xmit,
 	.ndo_get_stats       = veth_get_stats,
 	.ndo_set_mac_address = eth_mac_addr,
@@ -280,44 +291,6 @@ static void veth_setup(struct net_device *dev)
 	dev->destructor = veth_dev_free;
 }
 
-static void veth_change_state(struct net_device *dev)
-{
-	struct net_device *peer;
-	struct veth_priv *priv;
-
-	priv = netdev_priv(dev);
-	peer = priv->peer;
-
-	if (netif_carrier_ok(peer)) {
-		if (!netif_carrier_ok(dev))
-			netif_carrier_on(dev);
-	} else {
-		if (netif_carrier_ok(dev))
-			netif_carrier_off(dev);
-	}
-}
-
-static int veth_device_event(struct notifier_block *unused,
-			     unsigned long event, void *ptr)
-{
-	struct net_device *dev = ptr;
-
-	if (dev->netdev_ops->ndo_open != veth_open)
-		goto out;
-
-	switch (event) {
-	case NETDEV_CHANGE:
-		veth_change_state(dev);
-		break;
-	}
-out:
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block veth_notifier_block __read_mostly = {
-	.notifier_call	= veth_device_event,
-};
-
 /*
  * netlink interface
  */
@@ -468,14 +441,12 @@ static struct rtnl_link_ops veth_link_ops = {
 
 static __init int veth_init(void)
 {
-	register_netdevice_notifier(&veth_notifier_block);
 	return rtnl_link_register(&veth_link_ops);
 }
 
 static __exit void veth_exit(void)
 {
 	rtnl_link_unregister(&veth_link_ops);
-	unregister_netdevice_notifier(&veth_notifier_block);
 }
 
 module_init(veth_init);
-- 
1.6.1.2.350.g88cc

[PATCH 2/2] veth: Configurable nterface MTU

[Eric W. Biederman]

The limitation to only 1500 byte mtu's limits the utility of the veth
device for testing routing.

Signed-off-by: Eric Biederman <ebiederm@aristanetworks.com>
---
 drivers/net/veth.c |   24 +++++++++++++++++++++++-
 1 files changed, 23 insertions(+), 1 deletions(-)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 124fe75..88778bb 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -19,6 +19,10 @@
 #define DRV_NAME	"veth"
 #define DRV_VERSION	"1.0"
 
+#define MIN_MTU 68		/* Min L3 MTU */
+#define MAX_MTU 65535		/* Max L3 MTU (arbitrary) */
+#define MTU_PAD (ETH_HLEN + 4)  /* Max difference between L2 and L3 size MTU */
+
 struct veth_net_stats {
 	unsigned long	rx_packets;
 	unsigned long	tx_packets;
@@ -159,7 +163,7 @@ static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
 	cpu = smp_processor_id();
 	stats = per_cpu_ptr(priv->stats, cpu);
 
-	if (!(rcv->flags & IFF_UP))
+	if (!(rcv->flags & IFF_UP) || (skb->len > (rcv->mtu + MTU_PAD)))
 		goto outf;
 
 	skb->pkt_type = PACKET_HOST;
@@ -249,6 +253,19 @@ static int veth_close(struct net_device *dev)
 	return 0;
 }
 
+static int is_valid_veth_mtu(int new_mtu)
+{
+	return (new_mtu >= MIN_MTU && new_mtu <= MAX_MTU);
+}
+
+static int veth_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (is_valid_veth_mtu(new_mtu))
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
 static int veth_dev_init(struct net_device *dev)
 {
 	struct veth_net_stats *stats;
@@ -277,6 +294,7 @@ static const struct net_device_ops veth_netdev_ops = {
 	.ndo_open            = veth_open,
 	.ndo_stop            = veth_close,
 	.ndo_start_xmit      = veth_xmit,
+	.ndo_change_mtu      = veth_change_mtu,
 	.ndo_get_stats       = veth_get_stats,
 	.ndo_set_mac_address = eth_mac_addr,
 };
@@ -303,6 +321,10 @@ static int veth_validate(struct nlattr *tb[], struct nlattr *data[])
 		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
 			return -EADDRNOTAVAIL;
 	}
+	if (tb[IFLA_MTU]) {
+		if (is_valid_veth_mtu(nla_get_u32(tb[IFLA_MTU])))
+			return -EINVAL;
+	}
 	return 0;
 }
 
-- 
1.6.1.2.350.g88cc

Re: [PATCH 2/2] veth: Configurable nterface MTU

[David Miller]

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Wed, 25 Feb 2009 21:49:04 -0800

> @@ -249,6 +253,19 @@ static int veth_close(struct net_device *dev)
>  	return 0;
>  }
>  
> +static int is_valid_veth_mtu(int new_mtu)
> +{
> +	return (new_mtu >= MIN_MTU && new_mtu <= MAX_MTU);
> +}
> +
> +static int veth_change_mtu(struct net_device *dev, int new_mtu)
> +{
> +	if (is_valid_veth_mtu(new_mtu))
> +		return -EINVAL;
> +	dev->mtu = new_mtu;
> +	return 0;
> +}
> +

This validity test seems to be reversed?

Re: [PATCH 2/2] veth: Configurable nterface MTU

[Eric W. Biederman]

David Miller <davem@davemloft.net> writes:

> From: ebiederm@xmission.com (Eric W. Biederman)
> Date: Wed, 25 Feb 2009 21:49:04 -0800
>
>> @@ -249,6 +253,19 @@ static int veth_close(struct net_device *dev)
>>  	return 0;
>>  }
>>  
>> +static int is_valid_veth_mtu(int new_mtu)
>> +{
>> +	return (new_mtu >= MIN_MTU && new_mtu <= MAX_MTU);
>> +}
>> +
>> +static int veth_change_mtu(struct net_device *dev, int new_mtu)
>> +{
>> +	if (is_valid_veth_mtu(new_mtu))
>> +		return -EINVAL;
>> +	dev->mtu = new_mtu;
>> +	return 0;
>> +}
>> +
>
> This validity test seems to be reversed?

Crap.  You are correct. I will respin.

Eric

Re: [PATCH 2/2] veth: Configurable nterface MTU

[David Miller]

From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
Date: Fri, 27 Feb 2009 04:41:48 -0800

> David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> writes:
> 
> > From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)
> > Date: Wed, 25 Feb 2009 21:49:04 -0800
> >
> >> @@ -249,6 +253,19 @@ static int veth_close(struct net_device *dev)
> >>  	return 0;
> >>  }
> >>  
> >> +static int is_valid_veth_mtu(int new_mtu)
> >> +{
> >> +	return (new_mtu >= MIN_MTU && new_mtu <= MAX_MTU);
> >> +}
> >> +
> >> +static int veth_change_mtu(struct net_device *dev, int new_mtu)
> >> +{
> >> +	if (is_valid_veth_mtu(new_mtu))
> >> +		return -EINVAL;
> >> +	dev->mtu = new_mtu;
> >> +	return 0;
> >> +}
> >> +
> >
> > This validity test seems to be reversed?
> 
> Crap.  You are correct. I will respin.

Please test your patches.

This one obviously didn't get even one single "ifconfig x mtu y" type
test.  It would have failed on any in-range value.

Re: [PATCH 1/2] veth: Fix carrier detect

[David Miller]

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Wed, 25 Feb 2009 21:47:29 -0800

> 
> The current implementation of carrier detect in veth is broken.
> It reports the link is down until both sides of the veth pair
> are administatively up and then forever after it reports link up.
> 
> So fix veth so that it only reports link up when both interfaces
> of the pair are administratively up.
> 
> Signed-off-by: Eric Biederman <ebiederm@aristanetworks.com>

Applied.