From 50fb799289501c2eab9f43fc9af513027e1e994f Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 1 May 2015 11:30:12 -0700 Subject: 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 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 66e374d62f64..acb83e249e3f 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; -- cgit v1.2.3 From 2f59e1ebaa7f762c8825871b5486b5f5b4fa952f Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Fri, 1 May 2015 11:30:17 -0700 Subject: net: Add flow_keys digest Some users of flow keys (well just sch_choke now) need to pass flow_keys in skbuff cb, and use them for exact comparisons of flows so that skb->hash is not sufficient. In order to increase size of the flow_keys structure, we introduce another structure for the purpose of passing flow keys in skbuff cb. We limit this structure to sixteen bytes, and we will technically treat this as a digest of flow_keys struct hence its name flow_keys_digest. In the first incaranation we just copy the flow_keys structure up to 16 bytes-- this is the same information previously passed in the cb. In the future, we'll adapt this for larger flow_keys and could use something like SHA-1 over the whole flow_keys to improve the quality of the digest. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- include/net/flow_keys.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include') diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h index dc8fd81412bf..6d6ef626811a 100644 --- a/include/net/flow_keys.h +++ b/include/net/flow_keys.h @@ -42,4 +42,20 @@ static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 u32 flow_hash_from_keys(struct flow_keys *keys); unsigned int flow_get_hlen(const unsigned char *data, unsigned int max_len, __be16 protocol); + +/* struct flow_keys_digest: + * + * This structure is used to hold a digest of the full flow keys. This is a + * larger "hash" of a flow to allow definitively matching specific flows where + * the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so + * that it can by used in CB of skb (see sch_choke for an example). + */ +#define FLOW_KEYS_DIGEST_LEN 16 +struct flow_keys_digest { + u8 data[FLOW_KEYS_DIGEST_LEN]; +}; + +void make_flow_keys_digest(struct flow_keys_digest *digest, + const struct flow_keys *flow); + #endif -- cgit v1.2.3