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net: Add functions to get skb->hash based on flow structures

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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: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2015-07-31 16:52:10 -07:00 committed by David S. Miller
parent db316d57b6
commit f70ea018da
2 changed files with 75 additions and 4 deletions
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21
include/linux/skbuff.h
View file

@ -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)

58
net/core/flow_dissector.c
View file

@ -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)
{