#ifndef TUNNEL_H
#define TUNNEL_H 1
+#include <linux/version.h>
+
+#include "flow.h"
#include "openvswitch/tunnel.h"
#include "table.h"
#include "vport.h"
#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)
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 {
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 *);
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 */
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