Repository : ssh://git@open-mesh.org/batman-adv
On branch : master
commit 9eff62fcef81f356c63b47fcbe16465a562da684 Author: Antonio Quartulli ordex@autistici.org Date: Sun May 12 21:51:15 2013 +0200
batman-adv: h_vlan_encapsulated_proto access refactoring
In case of a 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. While this trickery is correct it makes the code harder to understand and may lead to bugs in case of re-use of ethhdr for other purposes.
This patch introduces a proto variable to make things cleaner and easier to understand.
Signed-off-by: Antonio Quartulli ordex@autistici.org Signed-off-by: Marek Lindner lindner_marek@yahoo.de
9eff62fcef81f356c63b47fcbe16465a562da684 gateway_client.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/gateway_client.c b/gateway_client.c index 973f02d..3a27408 100644 --- a/gateway_client.c +++ b/gateway_client.c @@ -626,24 +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; + struct vlan_ethhdr *vhdr; + __be16 proto;
/* check for ethernet header */ if (!pskb_may_pull(skb, *header_len + ETH_HLEN)) return false; ethhdr = (struct ethhdr *)skb->data; + proto = ethhdr->h_proto; *header_len += ETH_HLEN;
/* check for initial vlan header */ - if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) { + if (proto == __constant_htons(ETH_P_8021Q)) { if (!pskb_may_pull(skb, *header_len + VLAN_HLEN)) return false; - ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN); + + vhdr = (struct vlan_ethhdr *)skb->data; + proto = vhdr->h_vlan_encapsulated_proto; *header_len += VLAN_HLEN; }
/* check for ip header */ - switch (ntohs(ethhdr->h_proto)) { - case ETH_P_IP: + switch (proto) { + case __constant_htons(ETH_P_IP): if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr))) return false; iphdr = (struct iphdr *)(skb->data + *header_len); @@ -654,7 +659,7 @@ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) return false;
break; - case ETH_P_IPV6: + case __constant_htons(ETH_P_IPV6): if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr))) return false; ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len); @@ -675,11 +680,11 @@ bool batadv_gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len) *header_len += sizeof(*udphdr);
/* check for bootp port */ - if ((ntohs(ethhdr->h_proto) == ETH_P_IP) && + if ((proto == __constant_htons(ETH_P_IP)) && (ntohs(udphdr->dest) != 67)) return false;
- if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) && + if ((proto == __constant_htons(ETH_P_IPV6)) && (ntohs(udphdr->dest) != 547)) return false;