Subject: Re: [PATCH][CIPSO]: Relax too much careful cipso hash function.

From: Paul Moore <[email-masked]>
Date: Tue, 13 May 2008 14:34:44 -0400

On Tuesday 13 May 2008 9:11:25 am Pavel Emelyanov wrote:
> The cipso_v4_cache is allocated to contain CIPSO_V4_CACHE_BUCKETS
> buckets. The CIPSO_V4_CACHE_BUCKETS = 1 << CIPSO_V4_CACHE_BUCKETBITS,
> where CIPSO_V4_CACHE_BUCKETBITS = 7.
>
> The bucket-selection function for this hash is calculated like this:
>
>   bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
>                                      ^^^
>
> i.e. picking only 4 buckets of possible 128 :)
>
> Signed-off-by: Pavel Emelyanov <[email-masked]>

Thanks Pavel, braino on my part.

Acked-by: Paul Moore <[email-masked]>

> ---
>  net/ipv4/cipso_ipv4.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 05afb57..2c0e457 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -338,7 +338,7 @@ static int cipso_v4_cache_check(const unsigned
> char *key, return -ENOENT;
>
>  	hash = cipso_v4_map_cache_hash(key, key_len);
> -	bkt = hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
> +	bkt = hash & (CIPSO_V4_CACHE_BUCKETS - 1);
>  	spin_lock_bh(&cipso_v4_cache[bkt].lock);
>  	list_for_each_entry(entry, &cipso_v4_cache[bkt].list, list) {
>  		if (entry->hash == hash &&
> @@ -417,7 +417,7 @@ int cipso_v4_cache_add(const struct sk_buff *skb,
>  	atomic_inc(&secattr->cache->refcount);
>  	entry->lsm_data = secattr->cache;
>
> -	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETBITS - 1);
> +	bkt = entry->hash & (CIPSO_V4_CACHE_BUCKETS - 1);
>  	spin_lock_bh(&cipso_v4_cache[bkt].lock);
>  	if (cipso_v4_cache[bkt].size < cipso_v4_cache_bucketsize) {
>  		list_add(&entry->list, &cipso_v4_cache[bkt].list);

-- 
paul moore
linux @ hp