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2f59e1ebaa
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> Signed-off-by: David S. Miller <davem@davemloft.net>
61 lines
2 KiB
C
61 lines
2 KiB
C
#ifndef _NET_FLOW_KEYS_H
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#define _NET_FLOW_KEYS_H
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/* struct flow_keys:
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* @src: source ip address in case of IPv4
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* For IPv6 it contains 32bit hash of src address
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* @dst: destination ip address in case of IPv4
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* For IPv6 it contains 32bit hash of dst address
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* @ports: port numbers of Transport header
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* port16[0]: src port number
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* port16[1]: dst port number
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* @thoff: Transport header offset
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* @n_proto: Network header protocol (eg. IPv4/IPv6)
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* @ip_proto: Transport header protocol (eg. TCP/UDP)
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* All the members, except thoff, are in network byte order.
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*/
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struct flow_keys {
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/* (src,dst) must be grouped, in the same way than in IP header */
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__be32 src;
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__be32 dst;
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union {
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__be32 ports;
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__be16 port16[2];
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};
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u16 thoff;
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__be16 n_proto;
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u8 ip_proto;
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};
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bool __skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow,
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void *data, __be16 proto, int nhoff, int hlen);
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static inline bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
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{
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return __skb_flow_dissect(skb, flow, NULL, 0, 0, 0);
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}
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__be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
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void *data, int hlen_proto);
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static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto)
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{
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return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
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}
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u32 flow_hash_from_keys(struct flow_keys *keys);
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unsigned int flow_get_hlen(const unsigned char *data, unsigned int max_len,
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__be16 protocol);
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/* struct flow_keys_digest:
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*
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* This structure is used to hold a digest of the full flow keys. This is a
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* larger "hash" of a flow to allow definitively matching specific flows where
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* the 32 bit skb->hash is not large enough. The size is limited to 16 bytes so
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* that it can by used in CB of skb (see sch_choke for an example).
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*/
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#define FLOW_KEYS_DIGEST_LEN 16
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struct flow_keys_digest {
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u8 data[FLOW_KEYS_DIGEST_LEN];
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};
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void make_flow_keys_digest(struct flow_keys_digest *digest,
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const struct flow_keys *flow);
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#endif
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