batman-adv: send every DHCP packet as bat-unicast

In different situations it is possible that the DHCP server
or client uses broadcast Ethernet frames to send messages
to each other. The GW component in batman-adv takes care of
using bat-unicast packets to bring broadcast DHCP
Discover/Requests to the "best" server.

On the way back the DHCP server usually sends unicasts,
but upon client request it may decide to use broadcasts as
well.

This patch improves the GW component so that it now snoops
and sends as unicast all the DHCP packets, no matter if they
were generated by a DHCP server or client.

Signed-off-by: Antonio Quartulli <antonio@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>

1 files changed, 13 insertions, 3 deletions

diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index cea6578..30d12c4 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -319,13 +319,23 @@ out:
  */
 int batadv_send_skb_via_tt_generic(struct batadv_priv *bat_priv,
 				   struct sk_buff *skb, int packet_type,
-				   int packet_subtype, unsigned short vid)
+				   int packet_subtype, uint8_t *dst_hint,
+				   unsigned short vid)
 {
 	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
 	struct batadv_orig_node *orig_node;
+	uint8_t *src, *dst;
+
+	src = ethhdr->h_source;
+	dst = ethhdr->h_dest;
+
+	/* if we got an hint! let's send the packet to this client (if any) */
+	if (dst_hint) {
+		src = NULL;
+		dst = dst_hint;
+	}
+	orig_node = batadv_transtable_search(bat_priv, src, dst, vid);
 
-	orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
-					     ethhdr->h_dest, vid);
 	return batadv_send_skb_unicast(bat_priv, skb, packet_type,
 				       packet_subtype, orig_node, vid);
 }