Re: [PATCH] nfnetlink_queue: Use hash to speed up finding entries in nfqueue

[Patrick McHardy <kaber@trash.net>]

Changli Gao wrote:
> Use hash to speed up finding entries in nfqueue.
> 
> If user implements QoS in userland, packet verdict won't be received in order. At this moment, a hash table is faster than a double linked list when finding the corresponding entries in nfqueue.
> 
> This patch also fixes a potential bug, which will allows more than one entries with the same id are in the same nfqueue in the extreme.

Instead of a double ID in a purely hypothetical case, we'd now
get an endless loop. This part doesn't make much sense to me,
please remove it from the patch.

> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index 7a9dec9..38c7af1 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -37,6 +37,9 @@
>  #endif
>  
>  #define NFQNL_QMAX_DEFAULT 1024
> +#define NFQNL_QHT_BITS 8
> +#define NFQNL_QHT_SIZE (1 << NFQNL_QHT_BITS)
> +#define NFQNL_QHT_MASK (NFQNL_QHT_SIZE - 1)

Have you considered making the size configurable by passing a new
attribute in the NFQNL_CFG_CMD_BIND cmd message?