Merge branch 'AF_PACKET-transport_offset-fix'

Maxim Mikityanskiy says:

====================
AF_PACKET transport_offset fix

This patch series contains the implementation of the RFC that was posted
on this mailing list previously:
https://www.spinics.net/lists/netdev/msg541709.html

It fixes having incorrect skb->transport_header values in cases when
dissect fails. Having correct values set by the kernel fixes mlx5
operation and allows to remove some unnecessary code flows in mlx5.

v2 changes:

- Rebase against the fresh net-next.
- Don't return bool from skb_probe_transport_header (and don't rename
  the function).
- WARN_ON_ONCE and error path in case of GSO without the L4 header.
====================

Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 13 insertions, 5 deletions

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 2c0af7b00715..e2f3b21cd72a 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -44,6 +44,7 @@ int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh,
 		     __be16 type);
 void eth_header_cache_update(struct hh_cache *hh, const struct net_device *dev,
 			     const unsigned char *haddr);
+__be16 eth_header_parse_protocol(const struct sk_buff *skb);
 int eth_prepare_mac_addr_change(struct net_device *dev, void *p);
 void eth_commit_mac_addr_change(struct net_device *dev, void *p);
 int eth_mac_addr(struct net_device *dev, void *p);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index aab4d9f6613d..6997f62cb6a0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -274,6 +274,7 @@ struct header_ops {
 				const struct net_device *dev,
 				const unsigned char *haddr);
 	bool	(*validate)(const char *ll_header, unsigned int len);
+	__be16	(*parse_protocol)(const struct sk_buff *skb);
 };
 
 /* These flag bits are private to the generic network queueing
@@ -2939,6 +2940,15 @@ static inline int dev_parse_header(const struct sk_buff *skb,
 	return dev->header_ops->parse(skb, haddr);
 }
 
+static inline __be16 dev_parse_header_protocol(const struct sk_buff *skb)
+{
+	const struct net_device *dev = skb->dev;
+
+	if (!dev->header_ops || !dev->header_ops->parse_protocol)
+		return 0;
+	return dev->header_ops->parse_protocol(skb);
+}
+
 /* ll_header must have at least hard_header_len allocated */
 static inline bool dev_validate_header(const struct net_device *dev,
 				       char *ll_header, int len)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 2069fb90a559..27beb549ffbe 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2429,8 +2429,7 @@ static inline void skb_pop_mac_header(struct sk_buff *skb)
 	skb->mac_header = skb->network_header;
 }
 
-static inline void skb_probe_transport_header(struct sk_buff *skb,
-					      const int offset_hint)
+static inline void skb_probe_transport_header(struct sk_buff *skb)
 {
 	struct flow_keys_basic keys;
 
@@ -2439,8 +2438,6 @@ static inline void skb_probe_transport_header(struct sk_buff *skb,
 
 	if (skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0))
 		skb_set_transport_header(skb, keys.control.thoff);
-	else if (offset_hint >= 0)
-		skb_set_transport_header(skb, offset_hint);
 }
 
 static inline void skb_mac_header_rebuild(struct sk_buff *skb)
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 71f2394abbf7..6728bf581e98 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -62,7 +62,7 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb,
 		 * probe and drop if does not match one of the above types.
 		 */
 		if (gso_type) {
-			skb_probe_transport_header(skb, -1);
+			skb_probe_transport_header(skb);
 			if (!skb_transport_header_was_set(skb))
 				return -EINVAL;
 		}