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veth: Allow setting the L3 MTU 

The limitation to only 1500 byte mtu's limits the utility of the veth
device for testing routing.  So implement implement a configurable
MTU.

For consistency I drop packets on the receive side when they are
larger than the MTU.  I count those drops.  And I allow
a little padding for vlan headers.

I also test the mtu when a new device is created with netlink
because that path currently bypasses the current mtu setting
code.

Signed-off-by: Eric Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Biederman 2009-03-03 23:36:04 -08:00 committed by David S. Miller
parent abb79972b4
commit 38d408152a
1 changed files with 39 additions and 6 deletions
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45
drivers/net/veth.c
View File

@ -19,12 +19,17 @@
#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;
unsigned long rx_bytes;
unsigned long tx_bytes;
unsigned long tx_dropped;
unsigned long rx_dropped;
};
struct veth_priv {
@ -147,7 +152,7 @@ static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct net_device *rcv = NULL;
struct veth_priv *priv, *rcv_priv;
struct veth_net_stats *stats;
struct veth_net_stats *stats, *rcv_stats;
int length, cpu;
skb_orphan(skb);
@ -158,9 +163,13 @@ static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
cpu = smp_processor_id();
stats = per_cpu_ptr(priv->stats, cpu);
rcv_stats = per_cpu_ptr(rcv_priv->stats, cpu);
if (!(rcv->flags & IFF_UP))
goto outf;
goto tx_drop;
if (skb->len > (rcv->mtu + MTU_PAD))
goto rx_drop;
skb->pkt_type = PACKET_HOST;
skb->protocol = eth_type_trans(skb, rcv);
@ -178,17 +187,21 @@ static int veth_xmit(struct sk_buff *skb, struct net_device *dev)
stats->tx_bytes += length;
stats->tx_packets++;
stats = per_cpu_ptr(rcv_priv->stats, cpu);
stats->rx_bytes += length;
stats->rx_packets++;
rcv_stats->rx_bytes += length;
rcv_stats->rx_packets++;
netif_rx(skb);
return 0;
outf:
tx_drop:
kfree_skb(skb);
stats->tx_dropped++;
return 0;
rx_drop:
kfree_skb(skb);
rcv_stats->rx_dropped++;
return 0;
}
/*
@ -210,6 +223,7 @@ static struct net_device_stats *veth_get_stats(struct net_device *dev)
dev_stats->rx_bytes = 0;
dev_stats->tx_bytes = 0;
dev_stats->tx_dropped = 0;
dev_stats->rx_dropped = 0;
for_each_online_cpu(cpu) {
stats = per_cpu_ptr(priv->stats, cpu);
@ -219,6 +233,7 @@ static struct net_device_stats *veth_get_stats(struct net_device *dev)
dev_stats->rx_bytes += stats->rx_bytes;
dev_stats->tx_bytes += stats->tx_bytes;
dev_stats->tx_dropped += stats->tx_dropped;
dev_stats->rx_dropped += stats->rx_dropped;
}
return dev_stats;
@ -249,6 +264,19 @@ 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 +305,7 @@ 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 +332,10 @@ 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;
}