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-rw-r--r--net/core/flow_dissector.c48
1 files changed, 48 insertions, 0 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index d885e282908e..6883e22b8fc4 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -1,3 +1,4 @@
+#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/export.h>
#include <linux/ip.h>
@@ -15,6 +16,53 @@
#include <net/flow_dissector.h>
#include <scsi/fc/fc_fcoe.h>
+static bool skb_flow_dissector_uses_key(struct flow_dissector *flow_dissector,
+ enum flow_dissector_key_id key_id)
+{
+ return flow_dissector->used_keys & (1 << key_id);
+}
+
+static void skb_flow_dissector_set_key(struct flow_dissector *flow_dissector,
+ enum flow_dissector_key_id key_id)
+{
+ flow_dissector->used_keys |= (1 << key_id);
+}
+
+static void *skb_flow_dissector_target(struct flow_dissector *flow_dissector,
+ enum flow_dissector_key_id key_id,
+ void *target_container)
+{
+ return ((char *) target_container) + flow_dissector->offset[key_id];
+}
+
+void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
+ const struct flow_dissector_key *key,
+ unsigned int key_count)
+{
+ unsigned int i;
+
+ memset(flow_dissector, 0, sizeof(*flow_dissector));
+
+ for (i = 0; i < key_count; i++, key++) {
+ /* User should make sure that every key target offset is withing
+ * boundaries of unsigned short.
+ */
+ BUG_ON(key->offset > USHRT_MAX);
+ BUG_ON(skb_flow_dissector_uses_key(flow_dissector,
+ key->key_id));
+
+ skb_flow_dissector_set_key(flow_dissector, key->key_id);
+ flow_dissector->offset[key->key_id] = key->offset;
+ }
+
+ /* Ensure that the dissector always includes basic key. That way
+ * we are able to avoid handling lack of it in fast path.
+ */
+ BUG_ON(!skb_flow_dissector_uses_key(flow_dissector,
+ FLOW_DISSECTOR_KEY_BASIC));
+}
+EXPORT_SYMBOL(skb_flow_dissector_init);
+
/* copy saddr & daddr, possibly using 64bit load/store
* Equivalent to : flow->src = iph->saddr;
* flow->dst = iph->daddr;