Re: [B.A.T.M.A.N.] [RFC] batman-adv: Add function to calculate crc32c for the skb payload

["Martin Hundebøll" <martin@hundeboll.net>]

On 2012-10-17 17:59, Sven Eckelmann wrote:
> +__be32 batadv_crc32(const struct sk_buff *skb, u8 *payload_ptr)
> +{
> +	u32 crc = 0;
> +	struct sk_buff *iter;
> +	size_t skip_len, read_len;
> +	const skb_frag_t *f;
> +	int i;
> +
> +	skip_len = payload_ptr - skb->data;
> +	read_len = skb_headlen(skb) - skip_len;
> +	if (read_len)
> +		crc = crc32c(crc, payload_ptr, read_len);
> +
> +	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
> +		f = &skb_shinfo(skb)->frags[i];
> +		crc = crc32c(crc, skb_frag_address(f), skb_frag_size(f));
> +	}
> +
> +	skb_walk_frags(skb, iter)
> +		crc = crc32c(crc, iter->data, skb_headlen(iter));
> +
> +	return htonl(crc);
> +}

I tested the crc'ing of non-linear skb buffers and can confirm that it 
works as expected, so:

Tested-by: Martin Hundebøll <martin@hundeboll.net>

... at least for batadv_crc32() :)

-- 
Kind Regards
Martin Hundebøll
Frederiks Allé 99, 1.th
8000 Aarhus C
Denmark

+45 61 65 54 61
martin@hundeboll.net