Re: [B.A.T.M.A.N.] [PATCH 3/3] batman-adv: send DHCP requests directly to the chosen gw

[Andrew Lunn <andrew@lunn.ch>]

> +bool gw_is_target(struct sk_buff *skb)
> +{
> +	struct ethhdr *ethhdr;
> +	struct iphdr *iphdr;
> +	struct udphdr *udphdr;
> +
> +	if (atomic_read(&gw_mode) != GW_MODE_CLIENT)
> +		return false;
> +
> +	if (!curr_gateway)
> +		return false;
> +
> +	ethhdr = (struct ethhdr *)skb->data;
> +	if (ntohs(ethhdr->h_proto) != ETH_P_IP)
> +		return false;
> +
> +	iphdr = (struct iphdr *)(skb->data + ETH_HLEN);
> +
> +	if (iphdr->protocol != IPPROTO_UDP)
> +		return false;
> +
> +	udphdr = (struct udphdr *)(skb->data + ETH_HLEN + (iphdr->ihl * 4));
> +
> +	if (ntohs(udphdr->dest) != 67)
> +		return false;
> +
> +	return true;
> +}
> -	/* ethernet packet should be broadcasted */
> -	if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {
> +	if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest))
> +		bcast_dst = true;
> +
> +	if ((bcast_dst) && gw_is_target(skb))
> +		do_bcast = false;

Say the DHCP server is running in client mode. It has also been
requested to broadcast its replies, not unicast the replies.

http://blogs.technet.com/teamdhcp/archive/2009/02/12/dhcp-broadcast-flag-handling-in-windows-7.aspx

If i'm reading this code correctly, it will end up sending the DHCP
reply messages by unicast to the best gateway, not the DHCP client?

      Andrew