net: tunnel: make skb_vlan_inet_prepare() return drop reasons

commit 9990ddf upstream.

Make skb_vlan_inet_prepare return the skb drop reasons, which is just
what pskb_may_pull_reason() returns. Meanwhile, adjust all the call of
it.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: image-dragon

drivers/net/bareudp.c

@@ -317,7 +317,7 @@ static int bareudp_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be32 saddr;
 	int err;
 
-	if (!skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
+	if (skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
 		return -EINVAL;
 
 	if (!sock)
@@ -387,7 +387,7 @@ static int bareudp6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be16 sport;
 	int err;
 
-	if (!skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
+	if (skb_vlan_inet_prepare(skb, skb->protocol != htons(ETH_P_TEB)))
 		return -EINVAL;
 
 	if (!sock)

drivers/net/geneve.c

@@ -827,7 +827,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be16 sport;
 	int err;
 
-	if (!skb_vlan_inet_prepare(skb, inner_proto_inherit))
+	if (skb_vlan_inet_prepare(skb, inner_proto_inherit))
 		return -EINVAL;
 
 	if (!gs4)
@@ -937,7 +937,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
 	__be16 sport;
 	int err;
 
-	if (!skb_vlan_inet_prepare(skb, inner_proto_inherit))
+	if (skb_vlan_inet_prepare(skb, inner_proto_inherit))
 		return -EINVAL;
 
 	if (!gs6)

drivers/net/vxlan/vxlan_core.c

@@ -2381,7 +2381,7 @@ void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
 	__be32 vni = 0;
 
 	no_eth_encap = flags & VXLAN_F_GPE && skb->protocol != htons(ETH_P_TEB);
-	if (!skb_vlan_inet_prepare(skb, no_eth_encap))
+	if (skb_vlan_inet_prepare(skb, no_eth_encap))
 		goto drop;
 
 	old_iph = ip_hdr(skb);

include/net/ip_tunnels.h

@@ -467,11 +467,12 @@ static inline bool pskb_inet_may_pull(struct sk_buff *skb)
 
 /* Variant of pskb_inet_may_pull().
  */
-static inline bool skb_vlan_inet_prepare(struct sk_buff *skb,
-					 bool inner_proto_inherit)
+static inline enum skb_drop_reason
+skb_vlan_inet_prepare(struct sk_buff *skb, bool inner_proto_inherit)
 {
 	int nhlen = 0, maclen = inner_proto_inherit ? 0 : ETH_HLEN;
 	__be16 type = skb->protocol;
+	enum skb_drop_reason reason;
 
 	/* Essentially this is skb_protocol(skb, true)
 	 * And we get MAC len.
@@ -492,11 +493,13 @@ static inline bool skb_vlan_inet_prepare(struct sk_buff *skb,
 	/* For ETH_P_IPV6/ETH_P_IP we make sure to pull
 	 * a base network header in skb->head.
 	 */
-	if (!pskb_may_pull(skb, maclen + nhlen))
-		return false;
+	reason = pskb_may_pull_reason(skb, maclen + nhlen);
+	if (reason)
+		return reason;
 
 	skb_set_network_header(skb, maclen);
-	return true;
+
+	return SKB_NOT_DROPPED_YET;
 }
 
 static inline int ip_encap_hlen(struct ip_tunnel_encap *e)