Merge branch 'vxlan-skb-drop-reasons'

Menglong Dong says:

====================
net: vxlan: add skb drop reasons support

In this series, we add skb drop reasons support to VXLAN, and following
new skb drop reasons are introduced:

  SKB_DROP_REASON_VXLAN_INVALID_HDR
  SKB_DROP_REASON_VXLAN_VNI_NOT_FOUND
  SKB_DROP_REASON_VXLAN_ENTRY_EXISTS
  SKB_DROP_REASON_VXLAN_NO_REMOTE
  SKB_DROP_REASON_MAC_INVALID_SOURCE
  SKB_DROP_REASON_IP_TUNNEL_ECN
  SKB_DROP_REASON_TUNNEL_TXINFO
  SKB_DROP_REASON_LOCAL_MAC

We add some helper functions in this series, who will capture the drop
reasons from pskb_may_pull_reason and return them:

  pskb_network_may_pull_reason()
  pskb_inet_may_pull_reason()

And we also make the following functions return skb drop reasons:

  skb_vlan_inet_prepare()
  vxlan_remcsum()
  vxlan_snoop()
  vxlan_set_mac()

Changes since v6:
- fix some typos in the document for SKB_DROP_REASON_TUNNEL_TXINFO

Changes since v5:
- fix some typos in the document for SKB_DROP_REASON_TUNNEL_TXINFO

Changes since v4:
- make skb_vlan_inet_prepare() return drop reasons, instead of introduce
  a wrapper for it in the 3rd patch.
- modify the document for SKB_DROP_REASON_LOCAL_MAC and
  SKB_DROP_REASON_TUNNEL_TXINFO.

Changes since v3:
- rename SKB_DROP_REASON_VXLAN_INVALID_SMAC to
  SKB_DROP_REASON_MAC_INVALID_SOURCE in the 6th patch

Changes since v2:
- move all the drop reasons of VXLAN to the "core", instead of introducing
  the VXLAN drop reason subsystem
- add the 6th patch, which capture the drop reasons from vxlan_snoop()
- move the commits for vxlan_remcsum() and vxlan_set_mac() after
  vxlan_rcv() to update the call of them accordingly
- fix some format problems

Changes since v1:
- document all the drop reasons that we introduce
- rename the drop reasons to make them more descriptive, as Ido advised
- remove the 2nd patch, which introduce the SKB_DR_RESET
- add the 4th patch, which adds skb_vlan_inet_prepare_reason() helper
- introduce the 6th patch, which make vxlan_set_mac return drop reasons
- introduce the 10th patch, which uses VXLAN_DROP_NO_REMOTE as the drop
  reasons, as Ido advised
====================

Signed-off-by: David S. Miller <[email protected]>

3 files changed, 63 insertions, 8 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 39f1d16f3628..48f1e0fa2a13 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3130,9 +3130,15 @@ static inline int skb_inner_network_offset(const struct sk_buff *skb)
 	return skb_inner_network_header(skb) - skb->data;
 }
 
+static inline enum skb_drop_reason
+pskb_network_may_pull_reason(struct sk_buff *skb, unsigned int len)
+{
+	return pskb_may_pull_reason(skb, skb_network_offset(skb) + len);
+}
+
 static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
 {
-	return pskb_may_pull(skb, skb_network_offset(skb) + len);
+	return pskb_network_may_pull_reason(skb, len) == SKB_NOT_DROPPED_YET;
 }
 
 /*
diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 4748680e8c88..d59bb96c5a02 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -92,6 +92,14 @@
 	FN(PACKET_SOCK_ERROR)		\
 	FN(TC_CHAIN_NOTFOUND)		\
 	FN(TC_RECLASSIFY_LOOP)		\
+	FN(VXLAN_INVALID_HDR)		\
+	FN(VXLAN_VNI_NOT_FOUND)		\
+	FN(MAC_INVALID_SOURCE)		\
+	FN(VXLAN_ENTRY_EXISTS)		\
+	FN(VXLAN_NO_REMOTE)		\
+	FN(IP_TUNNEL_ECN)		\
+	FN(TUNNEL_TXINFO)		\
+	FN(LOCAL_MAC)			\
 	FNe(MAX)
 
 /**
@@ -419,6 +427,38 @@ enum skb_drop_reason {
 	 */
 	SKB_DROP_REASON_TC_RECLASSIFY_LOOP,
 	/**
+	 * @SKB_DROP_REASON_VXLAN_INVALID_HDR: VXLAN header is invalid. E.g.:
+	 * 1) reserved fields are not zero
+	 * 2) "I" flag is not set
+	 */
+	SKB_DROP_REASON_VXLAN_INVALID_HDR,
+	/** @SKB_DROP_REASON_VXLAN_VNI_NOT_FOUND: no VXLAN device found for VNI */
+	SKB_DROP_REASON_VXLAN_VNI_NOT_FOUND,
+	/** @SKB_DROP_REASON_MAC_INVALID_SOURCE: source mac is invalid */
+	SKB_DROP_REASON_MAC_INVALID_SOURCE,
+	/**
+	 * @SKB_DROP_REASON_VXLAN_ENTRY_EXISTS: trying to migrate a static
+	 * entry or an entry pointing to a nexthop.
+	 */
+	SKB_DROP_REASON_VXLAN_ENTRY_EXISTS,
+	/** @SKB_DROP_REASON_VXLAN_NO_REMOTE: no remote found for xmit */
+	SKB_DROP_REASON_VXLAN_NO_REMOTE,
+	/**
+	 * @SKB_DROP_REASON_IP_TUNNEL_ECN: skb is dropped according to
+	 * RFC 6040 4.2, see __INET_ECN_decapsulate() for detail.
+	 */
+	SKB_DROP_REASON_IP_TUNNEL_ECN,
+	/**
+	 * @SKB_DROP_REASON_TUNNEL_TXINFO: packet without necessary metadata
+	 * reached a device which is in "external" mode.
+	 */
+	SKB_DROP_REASON_TUNNEL_TXINFO,
+	/**
+	 * @SKB_DROP_REASON_LOCAL_MAC: the source MAC address is equal to
+	 * the MAC address of the local netdev.
+	 */
+	SKB_DROP_REASON_LOCAL_MAC,
+	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
 	 * shouldn't be used as a real 'reason' - only for tracing code gen
 	 */
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 6194fbb564c6..4e4f9e24c9c1 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -439,7 +439,8 @@ int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *op,
 int ip_tunnel_encap_setup(struct ip_tunnel *t,
 			  struct ip_tunnel_encap *ipencap);
 
-static inline bool pskb_inet_may_pull(struct sk_buff *skb)
+static inline enum skb_drop_reason
+pskb_inet_may_pull_reason(struct sk_buff *skb)
 {
 	int nhlen;
 
@@ -456,16 +457,22 @@ static inline bool pskb_inet_may_pull(struct sk_buff *skb)
 		nhlen = 0;
 	}
 
-	return pskb_network_may_pull(skb, nhlen);
+	return pskb_network_may_pull_reason(skb, nhlen);
+}
+
+static inline bool pskb_inet_may_pull(struct sk_buff *skb)
+{
+	return pskb_inet_may_pull_reason(skb) == SKB_NOT_DROPPED_YET;
 }
 
 /* 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.
@@ -486,11 +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)