From 50fb799289501c2eab9f43fc9af513027e1e994f Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 1 May 2015 11:30:12 -0700 Subject: [PATCH] net: Add skb_get_hash_perturb This calls flow_disect and __skb_get_hash to procure a hash for a packet. Input includes a key to initialize jhash. This function does not set skb->hash. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ net/core/flow_dissector.c | 38 ++++++++++++++++++++++++++++++-------- 2 files changed, 32 insertions(+), 8 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 66e374d..acb83e2 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -927,6 +927,8 @@ static inline __u32 skb_get_hash(struct sk_buff *skb) 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) { return skb->hash; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 2c35c02..b1df995 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -267,13 +267,12 @@ static __always_inline void __flow_hash_secret_init(void) net_get_random_once(&hashrnd, sizeof(hashrnd)); } -static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c) +static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c, u32 keyval) { - __flow_hash_secret_init(); - return jhash_3words(a, b, c, hashrnd); + return jhash_3words(a, b, c, keyval); } -static inline u32 __flow_hash_from_keys(struct flow_keys *keys) +static inline u32 __flow_hash_from_keys(struct flow_keys *keys, u32 keyval) { u32 hash; @@ -287,7 +286,8 @@ static inline u32 __flow_hash_from_keys(struct flow_keys *keys) hash = __flow_hash_3words((__force u32)keys->dst, (__force u32)keys->src, - (__force u32)keys->ports); + (__force u32)keys->ports, + keyval); if (!hash) hash = 1; @@ -296,10 +296,20 @@ static inline u32 __flow_hash_from_keys(struct flow_keys *keys) u32 flow_hash_from_keys(struct flow_keys *keys) { - return __flow_hash_from_keys(keys); + __flow_hash_secret_init(); + return __flow_hash_from_keys(keys, hashrnd); } EXPORT_SYMBOL(flow_hash_from_keys); +static inline u32 ___skb_get_hash(const struct sk_buff *skb, + struct flow_keys *keys, u32 keyval) +{ + if (!skb_flow_dissect(skb, keys)) + return 0; + + return __flow_hash_from_keys(keys, keyval); +} + /* * __skb_get_hash: calculate a flow hash based on src/dst addresses * and src/dst port numbers. Sets hash in skb to non-zero hash value @@ -309,8 +319,12 @@ EXPORT_SYMBOL(flow_hash_from_keys); void __skb_get_hash(struct sk_buff *skb) { struct flow_keys keys; + u32 hash; - if (!skb_flow_dissect(skb, &keys)) + __flow_hash_secret_init(); + + hash = ___skb_get_hash(skb, &keys, hashrnd); + if (!hash) return; if (keys.ports) @@ -318,10 +332,18 @@ void __skb_get_hash(struct sk_buff *skb) skb->sw_hash = 1; - skb->hash = __flow_hash_from_keys(&keys); + skb->hash = hash; } EXPORT_SYMBOL(__skb_get_hash); +__u32 skb_get_hash_perturb(const struct sk_buff *skb, u32 perturb) +{ + struct flow_keys keys; + + return ___skb_get_hash(skb, &keys, perturb); +} +EXPORT_SYMBOL(skb_get_hash_perturb); + /* * Returns a Tx hash based on the given packet descriptor a Tx queues' number * to be used as a distribution range. -- 2.7.4