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

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() :)