Commit f70ea018 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

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: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db316d57

include/linux/skbuff.h

+21 −0
Original line number Diff line number Diff line
@@ -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)

net/core/flow_dissector.c

+54 −4
Original line number Diff line number Diff line
@@ -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)

{

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