The limitation to only 1500 byte mtu's limits the utility of the veth
device for testing routing.
Signed-off-by: Eric Biederman <ebiederm@xxxxxxxxxxxxxxxxxx>
---
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
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