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authorDavid Wragg <david@weave.works>2016-02-18 20:43:29 +0300
committerDavid S. Miller <davem@davemloft.net>2016-02-18 21:57:15 +0300
commitaeee0e66c6b46cee311be22cb82735763eceb7c3 (patch)
tree15c5724ed408fbc8fbd5e9d54af92eb48f49758b /drivers/net/geneve.c
parent7716682cc58e305e22207d5bb315f26af6b1e243 (diff)
downloadlinux-aeee0e66c6b46cee311be22cb82735763eceb7c3.tar.xz
geneve: Refine MTU limit
Calculate the maximum MTU taking into account the size of headers involved in GENEVE encapsulation, as for other tunnel types. Changes in v3: - Correct comment style Changes in v2: - Conform more closely to ip_tunnel_change_mtu - Exclude GENEVE options from max MTU calculation Signed-off-by: David Wragg <david@weave.works> Acked-by: Jesse Gross <jesse@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/geneve.c')
-rw-r--r--drivers/net/geneve.c27
1 files changed, 22 insertions, 5 deletions
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 028e3873c310..70975700f91d 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1039,17 +1039,34 @@ static netdev_tx_t geneve_xmit(struct sk_buff *skb, struct net_device *dev)
return geneve_xmit_skb(skb, dev, info);
}
-static int geneve_change_mtu(struct net_device *dev, int new_mtu)
+static int __geneve_change_mtu(struct net_device *dev, int new_mtu, bool strict)
{
- /* GENEVE overhead is not fixed, so we can't enforce a more
- * precise max MTU.
+ /* The max_mtu calculation does not take account of GENEVE
+ * options, to avoid excluding potentially valid
+ * configurations.
*/
- if (new_mtu < 68 || new_mtu > IP_MAX_MTU)
+ int max_mtu = IP_MAX_MTU - GENEVE_BASE_HLEN - sizeof(struct iphdr)
+ - dev->hard_header_len;
+
+ if (new_mtu < 68)
return -EINVAL;
+
+ if (new_mtu > max_mtu) {
+ if (strict)
+ return -EINVAL;
+
+ new_mtu = max_mtu;
+ }
+
dev->mtu = new_mtu;
return 0;
}
+static int geneve_change_mtu(struct net_device *dev, int new_mtu)
+{
+ return __geneve_change_mtu(dev, new_mtu, true);
+}
+
static int geneve_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
{
struct ip_tunnel_info *info = skb_tunnel_info(skb);
@@ -1459,7 +1476,7 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
/* openvswitch users expect packet sizes to be unrestricted,
* so set the largest MTU we can.
*/
- err = geneve_change_mtu(dev, IP_MAX_MTU);
+ err = __geneve_change_mtu(dev, IP_MAX_MTU, false);
if (err)
goto err;