Message ID | 1430281661-2271966-7-git-send-email-tom@herbertland.com |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Tue, 2015-04-28 at 21:27 -0700, Tom Herbert wrote: > 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 <tom@herbertland.com> > --- > include/net/flow_keys.h | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h > index dc8fd81..f2610ad 100644 > --- a/include/net/flow_keys.h > +++ b/include/net/flow_keys.h > @@ -42,4 +42,23 @@ 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 used to hold a digest of the full flow keys. This is a larger > + * "hash" of a connection 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]; > +}; > + > +static inline void make_flow_keys_digest(struct flow_keys_digest *digest, > + struct flow_keys *flow) const struct flow_keys *flow > +{ Maybe document that src,dst,ports must be in first 16 bytes of flows_keys Some BUILD_BUG_ON() might do the trick > + memcpy(&digest->data, flow, FLOW_KEYS_DIGEST_LEN); > +} > + > #endif -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h index dc8fd81..f2610ad 100644 --- a/include/net/flow_keys.h +++ b/include/net/flow_keys.h @@ -42,4 +42,23 @@ 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 used to hold a digest of the full flow keys. This is a larger + * "hash" of a connection 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]; +}; + +static inline void make_flow_keys_digest(struct flow_keys_digest *digest, + struct flow_keys *flow) +{ + memcpy(&digest->data, flow, FLOW_KEYS_DIGEST_LEN); +} + #endif
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 <tom@herbertland.com> --- include/net/flow_keys.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)