- 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. */
- int hh_len; /* Hardware hdr length, cached from hh_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.
- */
- 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. */