net: Add functions to get skb->hash based on flow structures

Add skb_get_hash_flowi6 and skb_get_hash_flowi4 which derive an sk_buff
hash from flowi6 and flowi4 structures respectively. These functions
can be called when creating a packet in the output path where the new
sk_buff does not yet contain a fully formed packet that is parsable by
flow dissector.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 648a2c2419930dd8f5784d58cad738774fcd927b..b7c1286e247d9c50951ad8d9d1256ccc9d691481 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -37,6 +37,7 @@
 #include <net/flow_dissector.h>
 #include <linux/splice.h>
 #include <linux/in6.h>
+#include <net/flow.h>
 
 /* A. Checksumming of received packets by device.
  *
@@ -945,6 +946,26 @@ static inline __u32 skb_get_hash(struct sk_buff *skb)
        return skb->hash;
 }
 
+__u32 __skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6);
+
+static inline __u32 skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6)
+{
+       if (!skb->l4_hash && !skb->sw_hash)
+               __skb_get_hash_flowi6(skb, fl6);
+
+       return skb->hash;
+}
+
+__u32 __skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl);
+
+static inline __u32 skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl4)
+{
+       if (!skb->l4_hash && !skb->sw_hash)
+               __skb_get_hash_flowi4(skb, fl4);
+
+       return skb->hash;
+}
+
 __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb);
 
 static inline __u32 skb_get_hash_raw(const struct sk_buff *skb)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 2a834c6179b9973e45274d793e7d744939e5f49e..11e6540fa386918fe207b2e72e45b60d35ddb963 100644 (file)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -590,6 +590,15 @@ void make_flow_keys_digest(struct flow_keys_digest *digest,
 }
 EXPORT_SYMBOL(make_flow_keys_digest);
 
+static inline void __skb_set_sw_hash(struct sk_buff *skb, u32 hash,
+                                    struct flow_keys *keys)
+{
+       if (keys->ports.ports)
+               skb->l4_hash = 1;
+       skb->sw_hash = 1;
+       skb->hash = hash;
+}
+
 /**
  * __skb_get_hash: calculate a flow hash
  * @skb: sk_buff to calculate flow hash from
@@ -609,10 +618,8 @@ void __skb_get_hash(struct sk_buff *skb)
        hash = ___skb_get_hash(skb, &keys, hashrnd);
        if (!hash)
                return;
-       if (keys.ports.ports)
-               skb->l4_hash = 1;
-       skb->sw_hash = 1;
-       skb->hash = hash;
+
+       __skb_set_sw_hash(skb, hash, &keys);
 }
 EXPORT_SYMBOL(__skb_get_hash);
 
@@ -624,6 +631,49 @@ __u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb)
 }
 EXPORT_SYMBOL(skb_get_hash_perturb);
 
+__u32 __skb_get_hash_flowi6(struct sk_buff *skb, struct flowi6 *fl6)
+{
+       struct flow_keys keys;
+
+       memset(&keys, 0, sizeof(keys));
+
+       memcpy(&keys.addrs.v6addrs.src, &fl6->saddr,
+              sizeof(keys.addrs.v6addrs.src));
+       memcpy(&keys.addrs.v6addrs.dst, &fl6->daddr,
+              sizeof(keys.addrs.v6addrs.dst));
+       keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
+       keys.ports.src = fl6->fl6_sport;
+       keys.ports.dst = fl6->fl6_dport;
+       keys.keyid.keyid = fl6->fl6_gre_key;
+       keys.tags.flow_label = (__force u32)fl6->flowlabel;
+       keys.basic.ip_proto = fl6->flowi6_proto;
+
+       __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), &keys);
+
+       return skb->hash;
+}
+EXPORT_SYMBOL(__skb_get_hash_flowi6);
+
+__u32 __skb_get_hash_flowi4(struct sk_buff *skb, struct flowi4 *fl4)
+{
+       struct flow_keys keys;
+
+       memset(&keys, 0, sizeof(keys));
+
+       keys.addrs.v4addrs.src = fl4->saddr;
+       keys.addrs.v4addrs.dst = fl4->daddr;
+       keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+       keys.ports.src = fl4->fl4_sport;
+       keys.ports.dst = fl4->fl4_dport;
+       keys.keyid.keyid = fl4->fl4_gre_key;
+       keys.basic.ip_proto = fl4->flowi4_proto;
+
+       __skb_set_sw_hash(skb, flow_hash_from_keys(&keys), &keys);
+
+       return skb->hash;
+}
+EXPORT_SYMBOL(__skb_get_hash_flowi4);
+
 u32 __skb_get_poff(const struct sk_buff *skb, void *data,
                   const struct flow_keys *keys, int hlen)
 {