On Sun, May 12, 2013 at 03:25:10PM +0800, Marek Lindner wrote:
On Tuesday, May 07, 2013 19:54:02 Antonio Quartulli wrote:
In the gateway code in case of VLAN tagged frame the ethhdr pointer is moved forward by 4 bytes so that the offset of h_proto in struct ethhdr matches the real h_vlan_encapsulated_proto address in the skb.
This trick is correct but the code is not easy to understand and may lead to bugs in case of re-use of ethhdr for other purposes.
Use a standalone protocol variable and assign it accordingly to the header type
How about adding the key word "refactoring" somewhere into the subject line or the commit message ?
oky
@@ -626,23 +626,29 @@ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) struct iphdr *iphdr; struct ipv6hdr *ipv6hdr; struct udphdr *udphdr;
uint16_t proto;
/* check for ethernet header */ if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) return false; ethhdr = (struct ethhdr *)skb->data;
proto = ntohs(ethhdr->h_proto); *header_len += ETH_HLEN;
/* check for initial vlan header */
- if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
- if (proto == ETH_P_8021Q) {
struct vlan_ethhdr *vhdr;While we are refactoring I suggest to not ntohs() the protocol every time but the protocol constants. The compiler will replace the constants with the appropriate number during the compilation, thus saving us from a runtime operation every time we check a packet.
oh right. I did not think about it. I guess I have to use __constant_htons instead of the plain hntons.
cheers,
-- Antonio Quartulli
..each of us alone is worth nothing.. Ernesto "Che" Guevara