bluetooth: 6lowpan: use lowpan dispatch helpers

This patch adds a check if the dataroom of skb contains a dispatch value
by checking if skb->len != 0. This patch also change the dispatch
evaluation by the recently introduced helpers for checking the common
6LoWPAN dispatch values for IPv6 and IPHC header.

There was also a forgotten else branch which should drop the packet if
no matching dispatch is available.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Acked-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 27 insertions, 30 deletions

diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index db73b8a1433f..665bf38bd03b 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -314,15 +314,17 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
         if (!netif_running(dev))
                 goto drop;
 
-        if (dev->type != ARPHRD_6LOWPAN)
+        if (dev->type != ARPHRD_6LOWPAN || !skb->len)
                 goto drop;
 
+        skb_reset_network_header(skb);
+
         skb = skb_share_check(skb, GFP_ATOMIC);
         if (!skb)
                 goto drop;
 
         /* check that it's our buffer */
-        if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
+        if (lowpan_is_ipv6(*skb_network_header(skb))) {
                 /* Copy the packet so that the IPv6 header is
                  * properly aligned.
                  */
@@ -334,7 +336,6 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
                 local_skb->protocol = htons(ETH_P_IPV6);
                 local_skb->pkt_type = PACKET_HOST;
 
-                skb_reset_network_header(local_skb);
                 skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
 
                 if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
@@ -347,38 +348,34 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 
                 consume_skb(local_skb);
                 consume_skb(skb);
-        } else {
-                switch (skb->data[0] & 0xe0) {
-                case LOWPAN_DISPATCH_IPHC:      /* ipv6 datagram */
-                        local_skb = skb_clone(skb, GFP_ATOMIC);
-                        if (!local_skb)
-                                goto drop;
+        } else if (lowpan_is_iphc(*skb_network_header(skb))) {
+                local_skb = skb_clone(skb, GFP_ATOMIC);
+                if (!local_skb)
+                        goto drop;
 
-                        ret = iphc_decompress(local_skb, dev, chan);
-                        if (ret < 0) {
-                                kfree_skb(local_skb);
-                                goto drop;
-                        }
+                ret = iphc_decompress(local_skb, dev, chan);
+                if (ret < 0) {
+                        kfree_skb(local_skb);
+                        goto drop;
+                }
 
-                        local_skb->protocol = htons(ETH_P_IPV6);
-                        local_skb->pkt_type = PACKET_HOST;
-                        local_skb->dev = dev;
+                local_skb->protocol = htons(ETH_P_IPV6);
+                local_skb->pkt_type = PACKET_HOST;
+                local_skb->dev = dev;
 
-                        if (give_skb_to_upper(local_skb, dev)
-                                        != NET_RX_SUCCESS) {
-                                kfree_skb(local_skb);
-                                goto drop;
-                        }
+                if (give_skb_to_upper(local_skb, dev)
+                                != NET_RX_SUCCESS) {
+                        kfree_skb(local_skb);
+                        goto drop;
+                }
 
-                        dev->stats.rx_bytes += skb->len;
-                        dev->stats.rx_packets++;
+                dev->stats.rx_bytes += skb->len;
+                dev->stats.rx_packets++;
 
-                        consume_skb(local_skb);
-                        consume_skb(skb);
-                        break;
-                default:
-                        break;
-                }
+                consume_skb(local_skb);
+                consume_skb(skb);
+        } else {
+                goto drop;
         }
 
         return NET_RX_SUCCESS;