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Commit aa1c366e authored by dpward's avatar dpward Committed by David S. Miller
Browse files

net: Handle different key sizes between address families in flow cache 



With the conversion of struct flowi to a union of AF-specific structs, some
operations on the flow cache need to account for the exact size of the key.

Signed-off-by: default avatarDavid Ward <david.ward@ll.mit.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 728871bc

include/net/flow.h

+19 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#ifndef _NET_FLOW_H

#define _NET_FLOW_H



#include <linux/socket.h>

#include <linux/in6.h>

#include <linux/atomic.h>
@@ -161,6 +162,24 @@ static inline struct flowi *flowidn_to_flowi(struct flowidn *fldn) 
	return container_of(fldn, struct flowi, u.dn);

}



typedef unsigned long flow_compare_t;



static inline size_t flow_key_size(u16 family)

{

	switch (family) {

	case AF_INET:

		BUILD_BUG_ON(sizeof(struct flowi4) % sizeof(flow_compare_t));

		return sizeof(struct flowi4) / sizeof(flow_compare_t);

	case AF_INET6:

		BUILD_BUG_ON(sizeof(struct flowi6) % sizeof(flow_compare_t));

		return sizeof(struct flowi6) / sizeof(flow_compare_t);

	case AF_DECnet:

		BUILD_BUG_ON(sizeof(struct flowidn) % sizeof(flow_compare_t));

		return sizeof(struct flowidn) / sizeof(flow_compare_t);

	}

	return 0;

}



#define FLOW_DIR_IN	0

#define FLOW_DIR_OUT	1

#define FLOW_DIR_FWD	2

net/core/flow.c

+17 −14
Original line number Diff line number Diff line
@@ -173,29 +173,26 @@ static void flow_new_hash_rnd(struct flow_cache *fc, 


static u32 flow_hash_code(struct flow_cache *fc,

			  struct flow_cache_percpu *fcp,

			  const struct flowi *key)

			  const struct flowi *key,

			  size_t keysize)

{

	const u32 *k = (const u32 *) key;

	const u32 length = keysize * sizeof(flow_compare_t) / sizeof(u32);



	return jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)

	return jhash2(k, length, fcp->hash_rnd)

		& (flow_cache_hash_size(fc) - 1);

}



typedef unsigned long flow_compare_t;



/* I hear what you're saying, use memcmp.  But memcmp cannot make

 * important assumptions that we can here, such as alignment and

 * constant size.

 * important assumptions that we can here, such as alignment.

 */

static int flow_key_compare(const struct flowi *key1, const struct flowi *key2)

static int flow_key_compare(const struct flowi *key1, const struct flowi *key2,

			    size_t keysize)

{

	const flow_compare_t *k1, *k1_lim, *k2;

	const int n_elem = sizeof(struct flowi) / sizeof(flow_compare_t);



	BUILD_BUG_ON(sizeof(struct flowi) % sizeof(flow_compare_t));



	k1 = (const flow_compare_t *) key1;

	k1_lim = k1 + n_elem;

	k1_lim = k1 + keysize;



	k2 = (const flow_compare_t *) key2;
@@ -216,6 +213,7 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir, 
	struct flow_cache_entry *fle, *tfle;

	struct hlist_node *entry;

	struct flow_cache_object *flo;

	size_t keysize;

	unsigned int hash;



	local_bh_disable();
@@ -223,6 +221,11 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir, 


	fle = NULL;

	flo = NULL;



	keysize = flow_key_size(family);

	if (!keysize)

		goto nocache;



	/* Packet really early in init?  Making flow_cache_init a

	 * pre-smp initcall would solve this.  --RR */

	if (!fcp->hash_table)
@@ -231,12 +234,12 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir, 
	if (fcp->hash_rnd_recalc)

		flow_new_hash_rnd(fc, fcp);



	hash = flow_hash_code(fc, fcp, key);

	hash = flow_hash_code(fc, fcp, key, keysize);

	hlist_for_each_entry(tfle, entry, &fcp->hash_table[hash], u.hlist) {

		if (tfle->net == net &&

		    tfle->family == family &&

		    tfle->dir == dir &&

		    flow_key_compare(key, &tfle->key) == 0) {

		    flow_key_compare(key, &tfle->key, keysize) == 0) {

			fle = tfle;

			break;

		}
@@ -251,7 +254,7 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir, 
			fle->net = net;

			fle->family = family;

			fle->dir = dir;

			memcpy(&fle->key, key, sizeof(*key));

			memcpy(&fle->key, key, keysize * sizeof(flow_compare_t));

			fle->object = NULL;

			hlist_add_head(&fle->u.hlist, &fcp->hash_table[hash]);

			fcp->hash_count++;