net/flow_dissector: add packet hash dissection

Retreive a hash value from the SKB and store it
in the dissector key for future matching.

Signed-off-by: Ariel Levkovich <lariel@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6a82d4a..fa817a1 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1342,6 +1342,10 @@ skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
                             struct flow_dissector *flow_dissector,
                             void *target_container);
 
+void skb_flow_dissect_hash(const struct sk_buff *skb,
+                          struct flow_dissector *flow_dissector,
+                          void *target_container);
+
 static inline __u32 skb_get_hash(struct sk_buff *skb)
 {
        if (!skb->l4_hash && !skb->sw_hash)

diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 4b6e362..cc10b10 100644 (file)
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -243,6 +243,14 @@ struct flow_dissector_key_ct {
        u32     ct_labels[4];
 };
 
+/**
+ * struct flow_dissector_key_hash:
+ * @hash: hash value
+ */
+struct flow_dissector_key_hash {
+       u32 hash;
+};
+
 enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_CONTROL, /* struct flow_dissector_key_control */
        FLOW_DISSECTOR_KEY_BASIC, /* struct flow_dissector_key_basic */
@@ -271,6 +279,7 @@ enum flow_dissector_key_id {
        FLOW_DISSECTOR_KEY_ENC_OPTS, /* struct flow_dissector_key_enc_opts */
        FLOW_DISSECTOR_KEY_META, /* struct flow_dissector_key_meta */
        FLOW_DISSECTOR_KEY_CT, /* struct flow_dissector_key_ct */
+       FLOW_DISSECTOR_KEY_HASH, /* struct flow_dissector_key_hash */
 
        FLOW_DISSECTOR_KEY_MAX,
 };

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 142a882..29806eb 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -383,6 +383,23 @@ skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
 }
 EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
 
+void skb_flow_dissect_hash(const struct sk_buff *skb,
+                          struct flow_dissector *flow_dissector,
+                          void *target_container)
+{
+       struct flow_dissector_key_hash *key;
+
+       if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_HASH))
+               return;
+
+       key = skb_flow_dissector_target(flow_dissector,
+                                       FLOW_DISSECTOR_KEY_HASH,
+                                       target_container);
+
+       key->hash = skb_get_hash_raw(skb);
+}
+EXPORT_SYMBOL(skb_flow_dissect_hash);
+
 static enum flow_dissect_ret
 __skb_flow_dissect_mpls(const struct sk_buff *skb,
                        struct flow_dissector *flow_dissector,