1 files changed, 127 insertions, 26 deletions

diff --git a/datapath/tunnel.h b/datapath/tunnel.h
index 37874c57c..8ffb7bf54 100644
--- a/datapath/tunnel.h
+++ b/datapath/tunnel.h
@@ -9,6 +9,9 @@
 #ifndef TUNNEL_H
 #define TUNNEL_H 1
 
+#include <linux/version.h>
+
+#include "flow.h"
 #include "openvswitch/tunnel.h"
 #include "table.h"
 #include "vport.h"
@@ -20,14 +23,15 @@
 #define IP_MIN_MTU 68
 
 /*
- * One of these goes in your struct tnl_ops and in tnl_find_port().
+ * One of these goes in struct tnl_ops and in tnl_find_port().
  * These values are in the same namespace as other TNL_T_* values, so
- * you have only the first 10 bits to define protocol identifiers.
+ * only the least significant 10 bits are available to define protocol
+ * identifiers.
  */
 #define TNL_T_PROTO_GRE		0
 #define TNL_T_PROTO_CAPWAP	1
 
-/* You only need these flags when you are calling tnl_find_port(). */
+/* These flags are only needed when calling tnl_find_port(). */
 #define TNL_T_KEY_EXACT		(1 << 10)
 #define TNL_T_KEY_MATCH		(1 << 11)
 #define TNL_T_KEY_EITHER	(TNL_T_KEY_EXACT | TNL_T_KEY_MATCH)
@@ -35,39 +39,119 @@
 struct tnl_mutable_config {
 	struct rcu_head rcu;
 
-	unsigned char eth_addr[ETH_ALEN];
-	unsigned int mtu;
-	struct tnl_port_config port_config;
+	unsigned seq;		/* Sequence number to identify this config. */
 
-	/* Set of TNL_T_* flags that define the category for lookup. */
-	u32 tunnel_type;
+	u32 tunnel_type;	/* Set of TNL_T_* flags that define lookup. */
+	unsigned tunnel_hlen; 	/* Tunnel header length. */
+
+	unsigned char eth_addr[ETH_ALEN];
+	unsigned mtu;
 
-	int tunnel_hlen; /* Tunnel header length. */
+	struct tnl_port_config port_config;
 };
 
 struct tnl_ops {
-	/* Put your TNL_T_PROTO_* type in here. */
-	u32 tunnel_type;
-	u8 ipproto;
+	u32 tunnel_type;	/* Put the TNL_T_PROTO_* type in here. */
+	u8 ipproto;		/* The IP protocol for the tunnel. */
 
 	/*
-	 * Returns the length of the tunnel header you will add in
+	 * Returns the length of the tunnel header that will be added in
 	 * build_header() (i.e. excludes the IP header).  Returns a negative
 	 * error code if the configuration is invalid.
 	 */
 	int (*hdr_len)(const struct tnl_port_config *);
 
 	/*
-	 * Returns a linked list of SKBs with tunnel headers (multiple
-	 * packets may be generated in the event of fragmentation).  Space
-	 * will have already been allocated at the start of the packet equal
-	 * to sizeof(struct iphdr) + value returned by hdr_len().  The IP
-	 * header will have already been constructed.
+	 * Builds the static portion of the tunnel header, which is stored in
+	 * the header cache.  In general the performance of this function is
+	 * not too important as we try to only call it when building the cache
+	 * so it is preferable to shift as much work as possible here.  However,
+	 * in some circumstances caching is disabled and this function will be
+	 * called for every packet, so try not to make it too slow.
+	 */
+	void (*build_header)(const struct vport *,
+			     const struct tnl_mutable_config *, void *header);
+
+	/*
+	 * Updates the cached header of a packet to match the actual packet
+	 * data.  Typical things that might need to be updated are length,
+	 * checksum, etc.  The IP header will have already been updated and this
+	 * is the final step before transmission.  Returns a linked list of
+	 * completed SKBs (multiple packets may be generated in the event
+	 * of fragmentation).
+	 */
+	struct sk_buff *(*update_header)(const struct vport *,
+					 const struct tnl_mutable_config *,
+					 struct dst_entry *, struct sk_buff *);
+};
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
+/*
+ * On these kernels we have a fast mechanism to tell if the ARP cache for a
+ * particular destination has changed.
+ */
+#define HAVE_HH_SEQ
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,27)
+/*
+ * On these kernels we have a fast mechanism to tell if the routing table
+ * has changed.
+ */
+#define HAVE_RT_GENID
+#endif
+#if !defined(HAVE_HH_SEQ) || !defined(HAVE_RT_GENID)
+/* If we can't detect all system changes directly we need to use a timeout. */
+#define NEED_CACHE_TIMEOUT
+#endif
+struct tnl_cache {
+	struct rcu_head rcu;
+
+	int len;		/* Length of data to be memcpy'd from cache. */
+
+	/* Sequence number of mutable->seq from which this cache was generated. */
+	unsigned mutable_seq;
+
+#ifdef HAVE_HH_SEQ
+	/*
+	 * The sequence number from the seqlock protecting the hardware header
+	 * cache (in the ARP cache).  Since every write increments the counter
+	 * this gives us an easy way to tell if it has changed.
+	 */
+	unsigned hh_seq;
+#endif
+
+#ifdef NEED_CACHE_TIMEOUT
+	/*
+	 * If we don't have direct mechanisms to detect all important changes in
+	 * the system fall back to an expiration time.  This expiration time
+	 * can be relatively short since at high rates there will be millions of
+	 * packets per second, so we'll still get plenty of benefit from the
+	 * cache.  Note that if something changes we may blackhole packets
+	 * until the expiration time (depending on what changed and the kernel
+	 * version we may be able to detect the change sooner).  Expiration is
+	 * expressed as a time in jiffies.
 	 */
-	struct sk_buff *(*build_header)(struct sk_buff *,
-					const struct vport *,
-					const struct tnl_mutable_config *,
-					struct dst_entry *);
+	unsigned long expiration;
+#endif
+
+	/*
+	 * The routing table entry that is the result of looking up the tunnel
+	 * endpoints.  It also contains a sequence number (called a generation
+	 * ID) that can be compared to a global sequence to tell if the routing
+	 * table has changed (and therefore there is a potential that this
+	 * cached route has been invalidated).
+	 */
+	struct rtable *rt;
+
+	/*
+	 * If the output device for tunnel traffic is an OVS internal device,
+	 * the flow of that datapath.  Since all tunnel traffic will have the
+	 * same headers this allows us to cache the flow lookup.  NULL if the
+	 * output device is not OVS or if there is no flow installed.
+	 */
+	struct sw_flow *flow;
+
+	/* The cached header follows after padding for alignment. */
 };
 
 struct tnl_vport {
@@ -77,14 +161,29 @@ struct tnl_vport {
 	char name[IFNAMSIZ];
 	const struct tnl_ops *tnl_ops;
 
-	/* Protected by RCU. */
-	struct tnl_mutable_config *mutable;
+	struct tnl_mutable_config *mutable;	/* Protected by RCU. */
 
+	/*
+	 * ID of last fragment sent (for tunnel protocols with direct support
+	 * fragmentation).  If the protocol relies on IP fragmentation then
+	 * this is not needed.
+	 */
 	atomic_t frag_id;
+
+	spinlock_t cache_lock;
+	struct tnl_cache *cache;		/* Protected by RCU/cache_lock. */
+
+#ifdef NEED_CACHE_TIMEOUT
+	/*
+	 * If we must rely on expiration time to invalidate the cache, this is
+	 * the interval.  It is randomized within a range (defined by
+	 * MAX_CACHE_EXP in tunnel.c) to avoid synchronized expirations caused
+	 * by creation of a large number of tunnels at a one time.
+	 */
+	unsigned long cache_exp_interval;
+#endif
 };
 
-int tnl_init(void);
-void tnl_exit(void);
 struct vport *tnl_create(const char *name, const void __user *config,
 			 const struct vport_ops *,
 			 const struct tnl_ops *);
@@ -104,10 +203,12 @@ struct vport *tnl_find_port(__be32 saddr, __be32 daddr, __be32 key,
 bool tnl_frag_needed(struct vport *vport,
 		     const struct tnl_mutable_config *mutable,
 		     struct sk_buff *skb, unsigned int mtu, __be32 flow_key);
+void tnl_free_linked_skbs(struct sk_buff *skb);
 
 static inline struct tnl_vport *tnl_vport_priv(const struct vport *vport)
 {
 	return vport_priv(vport);
 }
 
+
 #endif /* tunnel.h */