This patch reworks the receive handling of bluetooth 6lowpan. I
introduce the same mechanism like we do in 802.15.4 6LoWPAN. Small
change is that I changed RX_QUEUED to RX_QUEUE, because it's not queued,
returning RX_QUEUE means the skb will be queued.
About the TODOs:
I added several TODOs which I am not sure how to handle it right now.
E.g. "skb->dev = dev", if this is really necessary, the current
implementation does it in IPHC and not in IPv6 dispatch value.
About memory management here:
This is currently wrong somehow, you can see that at the first call of
"skb_share_check", if this fails then the skb will be freed by
kfree_skb. But the previous error checks doesn't kfree_skb the skb. This
is a different handling for the same thing.
Jukka, please look how the ".recv" callback of "l2cap_ops" is working.
Who will free the skb? The ".recv" callback of "l2cap_ops" if returning
errno, or the callback itself need to do that. If it's when returning
errno, then you can't use skb_share_check/skb_unshare here.
I assume the callback itself need to do that.
Cc: Jukka Rissanen <jukka.rissanen@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Aring <alex.aring@xxxxxxxxx>
---
net/bluetooth/6lowpan.c | 157 +++++++++++++++++++++++++++++-------------------
1 file changed, 95 insertions(+), 62 deletions(-)
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index d936e7d..72ccbbf 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -29,6 +29,11 @@
#define VERSION "0.1"
+typedef unsigned __bitwise__ lowpan_rx_result;
+#define RX_CONTINUE ((__force lowpan_rx_result) 0u)
+#define RX_DROP_UNUSABLE ((__force lowpan_rx_result) 1u)
+#define RX_QUEUE ((__force lowpan_rx_result) 3u)
+
static struct dentry *lowpan_enable_debugfs;
static struct dentry *lowpan_control_debugfs;
@@ -257,13 +262,38 @@ static struct lowpan_dev *lookup_dev(struct l2cap_conn *conn)
static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
{
- struct sk_buff *skb_cp;
+ skb->protocol = htons(ETH_P_IPV6);
+ skb->pkt_type = PACKET_HOST;
+
+ dev->stats.rx_bytes += skb->len;
+ dev->stats.rx_packets++;
+
+ return netif_rx(skb);
+}
- skb_cp = skb_copy(skb, GFP_ATOMIC);
- if (!skb_cp)
+static int lowpan_rx_handlers_result(struct sk_buff *skb,
+ struct net_device *dev,
+ lowpan_rx_result res)
+{
+ switch (res) {
+ case RX_CONTINUE:
+ /* nobody cared about this packet */
+ net_warn_ratelimited("%s: received unknown dispatch\n",
+ __func__);
+
+ /* fall-through */
+ case RX_DROP_UNUSABLE:
+ kfree_skb(skb);
return NET_RX_DROP;
+ case RX_QUEUE:
+ return give_skb_to_upper(skb, dev);
+ default:
+ /* should never occur */
+ WARN_ON_ONCE(1);
+ break;
+ }
- return netif_rx(skb_cp);
+ return NET_RX_DROP;
}
static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
@@ -287,82 +317,85 @@ static int iphc_decompress(struct sk_buff *skb, struct net_device *netdev,
return lowpan_header_decompress(skb, netdev, daddr, saddr);
}
-static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
- struct l2cap_chan *chan)
+static lowpan_rx_result lowpan_rx_h_iphc(struct sk_buff *skb,
+ struct net_device *dev,
+ struct l2cap_chan *chan)
{
- struct sk_buff *local_skb;
int ret;
- if (!netif_running(dev))
- goto drop;
-
- if (dev->type != ARPHRD_6LOWPAN || !skb->len)
- goto drop;
-
- skb_reset_network_header(skb);
+ if (!lowpan_is_iphc(*skb_network_header(skb)))
+ return RX_CONTINUE;
- skb = skb_share_check(skb, GFP_ATOMIC);
- if (!skb)
- goto drop;
-
- /* check that it's our buffer */
- if (lowpan_is_ipv6(*skb_network_header(skb))) {
- /* Copy the packet so that the IPv6 header is
- * properly aligned.
- */
- local_skb = skb_copy_expand(skb, NET_SKB_PAD - 1,
- skb_tailroom(skb), GFP_ATOMIC);
- if (!local_skb)
- goto drop;
+ ret = iphc_decompress(skb, dev, chan);
+ if (ret < 0)
+ return RX_DROP_UNUSABLE;
- local_skb->protocol = htons(ETH_P_IPV6);
- local_skb->pkt_type = PACKET_HOST;
+ return RX_QUEUE;
+}
- skb_set_transport_header(local_skb, sizeof(struct ipv6hdr));
+static lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb,
+ struct net_device *dev,
+ struct l2cap_chan *chan)
+{
+ if (!lowpan_is_ipv6(*skb_network_header(skb)))
+ return RX_CONTINUE;
- if (give_skb_to_upper(local_skb, dev) != NET_RX_SUCCESS) {
- kfree_skb(local_skb);
- goto drop;
- }
+ /* Pull off the 1-byte of 6lowpan header. */
+ skb_pull(skb, 1);
+ return RX_QUEUE;
+}
- dev->stats.rx_bytes += skb->len;
- dev->stats.rx_packets++;
+static int lowpan_invoke_rx_handlers(struct sk_buff *skb,
+ struct net_device *dev,
+ struct l2cap_chan *chan)
+{
+ lowpan_rx_result res;
- consume_skb(local_skb);
- consume_skb(skb);
- } else if (lowpan_is_iphc(*skb_network_header(skb))) {
- local_skb = skb_clone(skb, GFP_ATOMIC);
- if (!local_skb)
- goto drop;
+#define CALL_RXH(rxh) \
+ do { \
+ res = rxh(skb, dev, chan); \
+ if (res != RX_CONTINUE) \
+ goto rxh_next; \
+ } while (0)
- ret = iphc_decompress(local_skb, dev, chan);
- if (ret < 0) {
- kfree_skb(local_skb);
- goto drop;
- }
+ /* likely at first */
+ CALL_RXH(lowpan_rx_h_iphc);
+ CALL_RXH(lowpan_rx_h_ipv6);
- local_skb->protocol = htons(ETH_P_IPV6);
- local_skb->pkt_type = PACKET_HOST;
- local_skb->dev = dev;
+rxh_next:
+ return lowpan_rx_handlers_result(skb, dev, res);
+}
- if (give_skb_to_upper(local_skb, dev)
- != NET_RX_SUCCESS) {
- kfree_skb(local_skb);
- goto drop;
- }
+static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
+ struct l2cap_chan *chan)
+{
+ /* TODO check for reserved, nalp dispatch here? */
+ if (!netif_running(dev) ||
+ dev->type != ARPHRD_6LOWPAN || !skb->len)
+ goto drop;
- dev->stats.rx_bytes += skb->len;
- dev->stats.rx_packets++;
+ /* we will manipulate the skb struct */
+ skb = skb_share_check(skb, GFP_ATOMIC);
+ if (!skb)
+ goto out;
- consume_skb(local_skb);
- consume_skb(skb);
- } else {
- goto drop;
+ /* TODO is this done by bluetooth callback, before? */
+ skb_reset_network_header(skb);
+ /* TODO really necessary? Previous did that in one branch only */
+ skb->dev = dev;
+
+ /* iphc will manipulate the skb buffer, unshare it */
+ if (lowpan_is_iphc(*skb_network_header(skb))) {
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (!skb)
+ goto out;
}
- return NET_RX_SUCCESS;
+ return lowpan_invoke_rx_handlers(skb, dev, chan);
drop:
+ kfree_skb(skb);
+out:
dev->stats.rx_dropped++;
return NET_RX_DROP;
}
--
2.6.1
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