[PATCH v2 bluetooth] Fix lowpan_rcv

[PATCH v2 bluetooth] Fix lowpan_rcv

[Martin Townsend]

This series aims to fix incorrect return values in lowpan_rcv
To achieve this it also refactors the receive path to
  1) free skb only from lowpan_rcv and not functions that it calls
  2) move skb delivery from IPHC

I have only compile tested the changes for bluetooth as I don't have any HW
available so would be grateful for any testing from the Bluetooth developers.
I have done some minimal testing for IEEE802.15.4

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
---

v1 -> v2:
* combined first two patches into one.
* split out renaming of process_data into a new patch
* re-use err in lowpan_process_data and remove err_ret local variable.
* removed third patch as applies to linux-wpan


Martin Townsend (1):
  6lowpan: fix incorrect return values in lowpan_rcv

 include/net/6lowpan.h         |  4 +--
 net/6lowpan/iphc.c            | 73 ++++++++++++++++++-------------------------
 net/bluetooth/6lowpan.c       | 26 +++++++++------
 net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
 4 files changed, 75 insertions(+), 72 deletions(-)

-- 
1.9.1

[PATCH v2 bluetooth] Fix lowpan_rcv

[Martin Townsend]

This series aims to fix incorrect return values in lowpan_rcv
To achieve this it also refactors the receive path to
  1) free skb only from lowpan_rcv and not functions that it calls
  2) move skb delivery from IPHC

I have only compile tested the changes for bluetooth as I don't have any HW
available so would be grateful for any testing from the Bluetooth developers.
I have done some minimal testing for IEEE802.15.4

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>

v1 -> v2:
* combined first two patches into one.
* split out renaming of process_data into a new patch
* re-use err in lowpan_process_data and remove err_ret local variable.
* removed third patch as applies to linux-wpan


*** BLURB HERE ***

Martin Townsend (1):
  6lowpan: fix incorrect return values in lowpan_rcv

 include/net/6lowpan.h         |  4 +--
 net/6lowpan/iphc.c            | 73 ++++++++++++++++++-------------------------
 net/bluetooth/6lowpan.c       | 26 +++++++++------
 net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
 4 files changed, 75 insertions(+), 72 deletions(-)

-- 
1.9.1

[PATCH v2 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Martin Townsend]

Currently there are a number of error paths in the lowpan_rcv function that
free the skb before returning, the patch simplifies the receive path by
ensuring that the skb is only freed from this function.

Passing the skb from 6lowpan up to the higher layers is not a
function of IPHC.  By moving it out of IPHC we also remove the
need to support error code returns with NET_RX codes.
It also makes the lowpan_rcv function more extendable as we
can support more compression schemes.

With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
---
 include/net/6lowpan.h         |  4 +--
 net/6lowpan/iphc.c            | 73 ++++++++++++++++++-------------------------
 net/bluetooth/6lowpan.c       | 26 +++++++++------
 net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
 4 files changed, 75 insertions(+), 72 deletions(-)

diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index d184df1..450eaaf 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
 
 typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
 
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
 		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
 		const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
-		u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
+		u8 iphc0, u8 iphc1);
 int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
 			unsigned short type, const void *_daddr,
 			const void *_saddr, unsigned int len);
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 142eef5..43ed1b4 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
 	return 0;
 }
 
-static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
-		       struct net_device *dev, skb_delivery_cb deliver_skb)
-{
-	struct sk_buff *new;
-	int stat;
-
-	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
-			      GFP_ATOMIC);
-	kfree_skb(skb);
-
-	if (!new)
-		return -ENOMEM;
-
-	skb_push(new, sizeof(struct ipv6hdr));
-	skb_reset_network_header(new);
-	skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
-
-	new->protocol = htons(ETH_P_IPV6);
-	new->pkt_type = PACKET_HOST;
-	new->dev = dev;
-
-	raw_dump_table(__func__, "raw skb data dump before receiving",
-		       new->data, new->len);
-
-	stat = deliver_skb(new, dev);
-
-	kfree_skb(new);
-
-	return stat;
-}
-
 /* Uncompress function for multicast destination address,
  * when M bit is set.
  */
@@ -332,14 +301,16 @@ err:
 /* TTL uncompression values */
 static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
 
-int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
 			const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
 			const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
-			u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
+			u8 iphc0, u8 iphc1)
 {
 	struct ipv6hdr hdr = {};
 	u8 tmp, num_context = 0;
 	int err;
+	int err_ret = -EINVAL;
+	struct sk_buff *skb = *skb_inout;
 
 	raw_dump_table(__func__, "raw skb data dump uncompressed",
 		       skb->data, skb->len);
@@ -460,7 +431,6 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
 	/* UDP data uncompression */
 	if (iphc0 & LOWPAN_IPHC_NH_C) {
 		struct udphdr uh;
-		struct sk_buff *new;
 
 		if (uncompress_udp_header(skb, &uh))
 			goto drop;
@@ -468,14 +438,15 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
 		/* replace the compressed UDP head by the uncompressed UDP
 		 * header
 		 */
-		new = skb_copy_expand(skb, sizeof(struct udphdr),
+		skb = skb_copy_expand(skb, sizeof(struct udphdr),
 				      skb_tailroom(skb), GFP_ATOMIC);
-		kfree_skb(skb);
-
-		if (!new)
-			return -ENOMEM;
+		if (!skb) {
+			err_ret = -ENOMEM;
+			goto drop;
+		}
 
-		skb = new;
+		kfree_skb(*skb_inout);
+		*skb_inout = skb;
 
 		skb_push(skb, sizeof(struct udphdr));
 		skb_reset_transport_header(skb);
@@ -499,11 +470,27 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
 
 	raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
 
-	return skb_deliver(skb, &hdr, dev, deliver_skb);
+	/* Setup skb with new uncompressed IPv6 header. */
+	skb = skb_copy_expand(skb, sizeof(hdr), skb_tailroom(skb),
+			      GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	kfree_skb(*skb_inout);
+	*skb_inout = skb;
+
+	skb_push(skb, sizeof(hdr));
+	skb_reset_network_header(skb);
+	skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
+	skb->dev = dev;
+
+	raw_dump_table(__func__, "raw skb data dump before receiving",
+		       skb->data, skb->len);
+
+	return 0;
 
 drop:
-	kfree_skb(skb);
-	return -EINVAL;
+	return err_ret;
 }
 EXPORT_SYMBOL_GPL(lowpan_process_data);
 
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index 206b65c..a4e340e 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -215,7 +215,7 @@ static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
 	return ret;
 }
 
-static int process_data(struct sk_buff *skb, struct net_device *netdev,
+static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
 			struct l2cap_chan *chan)
 {
 	const u8 *saddr, *daddr;
@@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
 	struct lowpan_dev *dev;
 	struct lowpan_peer *peer;
 	unsigned long flags;
+	struct sk_buff *skb = *skb_inout;
 
 	dev = lowpan_dev(netdev);
 
@@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
 	if (lowpan_fetch_skb_u8(skb, &iphc1))
 		goto drop;
 
-	return lowpan_process_data(skb, netdev,
+	return lowpan_process_data(skb_inout, netdev,
 				   saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
 				   daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
-				   iphc0, iphc1, give_skb_to_upper);
+				   iphc0, iphc1);
 
 drop:
-	kfree_skb(skb);
 	return -EINVAL;
 }
 
@@ -280,9 +280,6 @@ 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) {
 			kfree_skb(local_skb);
 			goto drop;
@@ -300,9 +297,20 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
 			if (!local_skb)
 				goto drop;
 
-			ret = process_data(local_skb, dev, chan);
-			if (ret != NET_RX_SUCCESS)
+			ret = process_data(&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;
+
+			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++;
diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 6591d27..d5bdeba 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -167,11 +167,13 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
 	return stat;
 }
 
-static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
+static int process_data(struct sk_buff **skb_inout,
+			const struct ieee802154_hdr *hdr)
 {
 	u8 iphc0, iphc1;
 	struct ieee802154_addr_sa sa, da;
 	void *sap, *dap;
+	struct sk_buff *skb = *skb_inout;
 
 	raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
 	/* at least two bytes will be used for the encoding */
@@ -197,13 +199,11 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
 	else
 		dap = &da.hwaddr;
 
-	return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
+	return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
 				   IEEE802154_ADDR_LEN, dap, da.addr_type,
-				   IEEE802154_ADDR_LEN, iphc0, iphc1,
-				   lowpan_give_skb_to_devices);
+				   IEEE802154_ADDR_LEN, iphc0, iphc1);
 
 drop:
-	kfree_skb(skb);
 	return -EINVAL;
 }
 
@@ -478,36 +478,35 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
 
 	/* check that it's our buffer */
 	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
-		skb->protocol = htons(ETH_P_IPV6);
-		skb->pkt_type = PACKET_HOST;
-
 		/* Pull off the 1-byte of 6lowpan header. */
 		skb_pull(skb, 1);
 
-		ret = lowpan_give_skb_to_devices(skb, NULL);
-		if (ret == NET_RX_DROP)
-			goto drop;
+		ret = NET_RX_SUCCESS;
 	} else {
 		switch (skb->data[0] & 0xe0) {
 		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
-			ret = process_data(skb, &hdr);
-			if (ret == NET_RX_DROP)
+			ret = process_data(&skb, &hdr);
+			if (ret < 0)
 				goto drop;
 			break;
 		case LOWPAN_DISPATCH_FRAG1:	/* first fragment header */
 			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
 			if (ret == 1) {
-				ret = process_data(skb, &hdr);
-				if (ret == NET_RX_DROP)
+				ret = process_data(&skb, &hdr);
+				if (ret < 0)
 					goto drop;
+			} else {
+				return NET_RX_SUCCESS;
 			}
 			break;
 		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
 			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
 			if (ret == 1) {
-				ret = process_data(skb, &hdr);
-				if (ret == NET_RX_DROP)
+				ret = process_data(&skb, &hdr);
+				if (ret < 0)
 					goto drop;
+			} else {
+				return NET_RX_SUCCESS;
 			}
 			break;
 		default:
@@ -515,7 +514,16 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
 		}
 	}
 
-	return NET_RX_SUCCESS;
+	/* Pass IPv6 packet up to next layer */
+	skb->protocol = htons(ETH_P_IPV6);
+	skb->pkt_type = PACKET_HOST;
+	ret = lowpan_give_skb_to_devices(skb, NULL);
+	if (ret < 0)
+		goto drop_skb;
+
+	kfree_skb(skb);
+	return ret;
+
 drop_skb:
 	kfree_skb(skb);
 drop:
-- 
1.9.1

Re: [PATCH v2 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Alexander Aring]

Hi Martin,

something is wrong with you mail client. I received the cover letter
twice one has some wrong reply-to id. Please check this.

Do you use git send-email? How, maybe we can help you there.

On Fri, Sep 12, 2014 at 10:34:40AM +0100, Martin Townsend wrote:
> Currently there are a number of error paths in the lowpan_rcv function that
> free the skb before returning, the patch simplifies the receive path by
> ensuring that the skb is only freed from this function.
> 
> Passing the skb from 6lowpan up to the higher layers is not a
> function of IPHC.  By moving it out of IPHC we also remove the
> need to support error code returns with NET_RX codes.
> It also makes the lowpan_rcv function more extendable as we
> can support more compression schemes.
> 
> With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
> 
> Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
> ---
>  include/net/6lowpan.h         |  4 +--
>  net/6lowpan/iphc.c            | 73 ++++++++++++++++++-------------------------
>  net/bluetooth/6lowpan.c       | 26 +++++++++------
>  net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
>  4 files changed, 75 insertions(+), 72 deletions(-)
> 
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index d184df1..450eaaf 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
>  
>  typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
>  
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>  		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
>  		const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> -		u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
> +		u8 iphc0, u8 iphc1);

check checkpatch here.

CHECK: Alignment should match open parenthesis
#37: FILE: include/net/6lowpan.h:378:
+int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
 		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,

>  int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
>  			unsigned short type, const void *_daddr,
>  			const void *_saddr, unsigned int len);
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 142eef5..43ed1b4 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
>  	return 0;
>  }
>  
> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
> -		       struct net_device *dev, skb_delivery_cb deliver_skb)
> -{
> -	struct sk_buff *new;
> -	int stat;
> -
> -	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
> -			      GFP_ATOMIC);
> -	kfree_skb(skb);
> -
> -	if (!new)
> -		return -ENOMEM;
> -
> -	skb_push(new, sizeof(struct ipv6hdr));
> -	skb_reset_network_header(new);
> -	skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
> -
> -	new->protocol = htons(ETH_P_IPV6);
> -	new->pkt_type = PACKET_HOST;
> -	new->dev = dev;
> -
> -	raw_dump_table(__func__, "raw skb data dump before receiving",
> -		       new->data, new->len);
> -
> -	stat = deliver_skb(new, dev);
> -
> -	kfree_skb(new);
> -
> -	return stat;
> -}
> -
>  /* Uncompress function for multicast destination address,
>   * when M bit is set.
>   */
> @@ -332,14 +301,16 @@ err:
>  /* TTL uncompression values */
>  static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
>  
> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>  			const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
>  			const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
> -			u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
> +			u8 iphc0, u8 iphc1)
>  {
>  	struct ipv6hdr hdr = {};
>  	u8 tmp, num_context = 0;
>  	int err;
> +	int err_ret = -EINVAL;

use err here, I saw this in your cover-letter as change but it's not
really changed.

> +	struct sk_buff *skb = *skb_inout;
>  
>  	raw_dump_table(__func__, "raw skb data dump uncompressed",
>  		       skb->data, skb->len);
> @@ -460,7 +431,6 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>  	/* UDP data uncompression */
>  	if (iphc0 & LOWPAN_IPHC_NH_C) {
>  		struct udphdr uh;
> -		struct sk_buff *new;
>  
>  		if (uncompress_udp_header(skb, &uh))
>  			goto drop;
> @@ -468,14 +438,15 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>  		/* replace the compressed UDP head by the uncompressed UDP
>  		 * header
>  		 */
> -		new = skb_copy_expand(skb, sizeof(struct udphdr),
> +		skb = skb_copy_expand(skb, sizeof(struct udphdr),
>  				      skb_tailroom(skb), GFP_ATOMIC);
> -		kfree_skb(skb);
> -
> -		if (!new)
> -			return -ENOMEM;
> +		if (!skb) {
> +			err_ret = -ENOMEM;
> +			goto drop;
> +		}
>  
> -		skb = new;
> +		kfree_skb(*skb_inout);
> +		*skb_inout = skb;
>  
>  		skb_push(skb, sizeof(struct udphdr));
>  		skb_reset_transport_header(skb);
> @@ -499,11 +470,27 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>  
>  	raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
>  
> -	return skb_deliver(skb, &hdr, dev, deliver_skb);
> +	/* Setup skb with new uncompressed IPv6 header. */
> +	skb = skb_copy_expand(skb, sizeof(hdr), skb_tailroom(skb),
> +			      GFP_ATOMIC);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	kfree_skb(*skb_inout);
> +	*skb_inout = skb;
> +
> +	skb_push(skb, sizeof(hdr));
> +	skb_reset_network_header(skb);
> +	skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
> +	skb->dev = dev;
> +
> +	raw_dump_table(__func__, "raw skb data dump before receiving",
> +		       skb->data, skb->len);
> +
> +	return 0;
>  
>  drop:
> -	kfree_skb(skb);
> -	return -EINVAL;
> +	return err_ret;
>  }
>  EXPORT_SYMBOL_GPL(lowpan_process_data);
>  
> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
> index 206b65c..a4e340e 100644
> --- a/net/bluetooth/6lowpan.c
> +++ b/net/bluetooth/6lowpan.c
> @@ -215,7 +215,7 @@ static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
>  	return ret;
>  }
>  
> -static int process_data(struct sk_buff *skb, struct net_device *netdev,
> +static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
>  			struct l2cap_chan *chan)
>  {
>  	const u8 *saddr, *daddr;
> @@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
>  	struct lowpan_dev *dev;
>  	struct lowpan_peer *peer;
>  	unsigned long flags;
> +	struct sk_buff *skb = *skb_inout;
>  
>  	dev = lowpan_dev(netdev);
>  
> @@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
>  	if (lowpan_fetch_skb_u8(skb, &iphc1))
>  		goto drop;
>  
> -	return lowpan_process_data(skb, netdev,
> +	return lowpan_process_data(skb_inout, netdev,
>  				   saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
>  				   daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
> -				   iphc0, iphc1, give_skb_to_upper);
> +				   iphc0, iphc1);
>  
>  drop:
> -	kfree_skb(skb);
>  	return -EINVAL;
>  }
>  
> @@ -280,9 +280,6 @@ 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) {
>  			kfree_skb(local_skb);
>  			goto drop;
> @@ -300,9 +297,20 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
>  			if (!local_skb)
>  				goto drop;
>  
> -			ret = process_data(local_skb, dev, chan);
> -			if (ret != NET_RX_SUCCESS)
> +			ret = process_data(&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;
> +
> +			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++;
> diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
> index 6591d27..d5bdeba 100644
> --- a/net/ieee802154/6lowpan_rtnl.c
> +++ b/net/ieee802154/6lowpan_rtnl.c
> @@ -167,11 +167,13 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
>  	return stat;
>  }
>  
> -static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
> +static int process_data(struct sk_buff **skb_inout,
> +			const struct ieee802154_hdr *hdr)
>  {
>  	u8 iphc0, iphc1;
>  	struct ieee802154_addr_sa sa, da;
>  	void *sap, *dap;
> +	struct sk_buff *skb = *skb_inout;
>  
>  	raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
>  	/* at least two bytes will be used for the encoding */
> @@ -197,13 +199,11 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
>  	else
>  		dap = &da.hwaddr;
>  
> -	return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
> +	return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
>  				   IEEE802154_ADDR_LEN, dap, da.addr_type,
> -				   IEEE802154_ADDR_LEN, iphc0, iphc1,
> -				   lowpan_give_skb_to_devices);
> +				   IEEE802154_ADDR_LEN, iphc0, iphc1);
>  
>  drop:
> -	kfree_skb(skb);
>  	return -EINVAL;
>  }
>  
> @@ -478,36 +478,35 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>  
>  	/* check that it's our buffer */
>  	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
> -		skb->protocol = htons(ETH_P_IPV6);
> -		skb->pkt_type = PACKET_HOST;
> -
>  		/* Pull off the 1-byte of 6lowpan header. */
>  		skb_pull(skb, 1);
>  
> -		ret = lowpan_give_skb_to_devices(skb, NULL);
> -		if (ret == NET_RX_DROP)
> -			goto drop;
> +		ret = NET_RX_SUCCESS;
>  	} else {
>  		switch (skb->data[0] & 0xe0) {
>  		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
> -			ret = process_data(skb, &hdr);
> -			if (ret == NET_RX_DROP)
> +			ret = process_data(&skb, &hdr);
> +			if (ret < 0)
>  				goto drop;
>  			break;
>  		case LOWPAN_DISPATCH_FRAG1:	/* first fragment header */
>  			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);

can also return "-1" for error but in this case the skb is already freed.
so some else if with NET_RX_DROP. I know it was not handled before but we
should handle this right now, when we care about the error handling.

>  			if (ret == 1) {
> -				ret = process_data(skb, &hdr);
> -				if (ret == NET_RX_DROP)
> +				ret = process_data(&skb, &hdr);
> +				if (ret < 0)
>  					goto drop;
this function returning an errno, you can't return the errno here. goto
drop returns the ret variable. Maybe just make a return NET_RX_DROP at
drop. We should never return a different variable.

Also this need to be drop_skb at several places in this code, we don't
have a kfree_skb at process_data anymore. This leaks memory.

> +			} else {
> +				return NET_RX_SUCCESS;
>  			}
>  			break;
>  		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
>  			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);

same here.
>  			if (ret == 1) {
> -				ret = process_data(skb, &hdr);
> -				if (ret == NET_RX_DROP)
> +				ret = process_data(&skb, &hdr);
> +				if (ret < 0)
>  					goto drop;

same here.

> +			} else {
> +				return NET_RX_SUCCESS;
>  			}
>  			break;
>  		default:
> @@ -515,7 +514,16 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>  		}
>  	}
>  
> -	return NET_RX_SUCCESS;
> +	/* Pass IPv6 packet up to next layer */
> +	skb->protocol = htons(ETH_P_IPV6);
> +	skb->pkt_type = PACKET_HOST;
> +	ret = lowpan_give_skb_to_devices(skb, NULL);

grml, see possible merge conflicts here. In next should be no dev
parameter anymore. Nevertheless should easy to fix it.

> +	if (ret < 0)
> +		goto drop_skb;
> +

Also here that's too broken here. In lowpan_give_skb_to_devices we have
mixed errno and  NET_RX_SUCCESS for the return variable, we need to
clean this up. Maybe just return the NET_RX_SUCCESS|NET_RX_DROP return
value from netif_rx call.

> +	kfree_skb(skb);

consume_skb here.

Simple on error kfree_skb, not a error consume_skb or dev_kfree_skb. I
prefer consume_skb.

- Alex

Re: [PATCH v2 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Alexander Aring]

On Mon, Sep 15, 2014 at 12:13:31PM +0200, Alexander Aring wrote:
...
> 
> >  			if (ret == 1) {
> > -				ret = process_data(skb, &hdr);
> > -				if (ret == NET_RX_DROP)
> > +				ret = process_data(&skb, &hdr);
> > +				if (ret < 0)
> >  					goto drop;
> this function returning an errno, you can't return the errno here. goto
> drop returns the ret variable. Maybe just make a return NET_RX_DROP at
> drop. We should never return a different variable.
Oops, I looked at the wong please I mean before drop, when all things
are fine.

> 
> Also this need to be drop_skb at several places in this code, we don't
> have a kfree_skb at process_data anymore. This leaks memory.
> 
> > +			} else {
> > +				return NET_RX_SUCCESS;
> >  			}
> >  			break;
> >  		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
> >  			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
> 
> same here.
> >  			if (ret == 1) {
> > -				ret = process_data(skb, &hdr);
> > -				if (ret == NET_RX_DROP)
> > +				ret = process_data(&skb, &hdr);
> > +				if (ret < 0)
> >  					goto drop;
> 
> same here.
> 
> > +			} else {
> > +				return NET_RX_SUCCESS;
> >  			}
> >  			break;
> >  		default:
> > @@ -515,7 +514,16 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
> >  		}
> >  	}
> >  

If all things are fine, there is somewhere a return ret;

We should change it to return NET_RX_SUCCESS.

- Alex

Re: [PATCH v2 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Martin Townsend]

Hi Alex,

Thanks for the review, I have one question below, when answered I'll respin a v3 patch.

On 15/09/14 11:13, Alexander Aring wrote:
> Hi Martin,
>
> something is wrong with you mail client. I received the cover letter
> twice one has some wrong reply-to id. Please check this.
I did use git send-email, but my editor left a 0000-cover-letter.patch~   :(
I'll remove these in future.
>
> Do you use git send-email? How, maybe we can help you there.
>
> On Fri, Sep 12, 2014 at 10:34:40AM +0100, Martin Townsend wrote:
>> Currently there are a number of error paths in the lowpan_rcv function that
>> free the skb before returning, the patch simplifies the receive path by
>> ensuring that the skb is only freed from this function.
>>
>> Passing the skb from 6lowpan up to the higher layers is not a
>> function of IPHC.  By moving it out of IPHC we also remove the
>> need to support error code returns with NET_RX codes.
>> It also makes the lowpan_rcv function more extendable as we
>> can support more compression schemes.
>>
>> With the above 2 lowpan_rcv is refacored so eliminate incorrect return values.
>>
>> Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
>> ---
>>  include/net/6lowpan.h         |  4 +--
>>  net/6lowpan/iphc.c            | 73 ++++++++++++++++++-------------------------
>>  net/bluetooth/6lowpan.c       | 26 +++++++++------
>>  net/ieee802154/6lowpan_rtnl.c | 44 +++++++++++++++-----------
>>  4 files changed, 75 insertions(+), 72 deletions(-)
>>
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index d184df1..450eaaf 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -374,10 +374,10 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
>>  
>>  typedef int (*skb_delivery_cb)(struct sk_buff *skb, struct net_device *dev);
>>  
>> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>>  		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
>>  		const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
>> -		u8 iphc0, u8 iphc1, skb_delivery_cb skb_deliver);
>> +		u8 iphc0, u8 iphc1);
> check checkpatch here.
>
> CHECK: Alignment should match open parenthesis
> #37: FILE: include/net/6lowpan.h:378:
> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>  		const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
This hasn't been introduced by me I've just removed skb_deliver.
>>  int lowpan_header_compress(struct sk_buff *skb, struct net_device *dev,
>>  			unsigned short type, const void *_daddr,
>>  			const void *_saddr, unsigned int len);
>> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
>> index 142eef5..43ed1b4 100644
>> --- a/net/6lowpan/iphc.c
>> +++ b/net/6lowpan/iphc.c
>> @@ -171,37 +171,6 @@ static int uncompress_context_based_src_addr(struct sk_buff *skb,
>>  	return 0;
>>  }
>>  
>> -static int skb_deliver(struct sk_buff *skb, struct ipv6hdr *hdr,
>> -		       struct net_device *dev, skb_delivery_cb deliver_skb)
>> -{
>> -	struct sk_buff *new;
>> -	int stat;
>> -
>> -	new = skb_copy_expand(skb, sizeof(struct ipv6hdr), skb_tailroom(skb),
>> -			      GFP_ATOMIC);
>> -	kfree_skb(skb);
>> -
>> -	if (!new)
>> -		return -ENOMEM;
>> -
>> -	skb_push(new, sizeof(struct ipv6hdr));
>> -	skb_reset_network_header(new);
>> -	skb_copy_to_linear_data(new, hdr, sizeof(struct ipv6hdr));
>> -
>> -	new->protocol = htons(ETH_P_IPV6);
>> -	new->pkt_type = PACKET_HOST;
>> -	new->dev = dev;
>> -
>> -	raw_dump_table(__func__, "raw skb data dump before receiving",
>> -		       new->data, new->len);
>> -
>> -	stat = deliver_skb(new, dev);
>> -
>> -	kfree_skb(new);
>> -
>> -	return stat;
>> -}
>> -
>>  /* Uncompress function for multicast destination address,
>>   * when M bit is set.
>>   */
>> @@ -332,14 +301,16 @@ err:
>>  /* TTL uncompression values */
>>  static const u8 lowpan_ttl_values[] = { 0, 1, 64, 255 };
>>  
>> -int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>> +int lowpan_process_data(struct sk_buff **skb_inout, struct net_device *dev,
>>  			const u8 *saddr, const u8 saddr_type, const u8 saddr_len,
>>  			const u8 *daddr, const u8 daddr_type, const u8 daddr_len,
>> -			u8 iphc0, u8 iphc1, skb_delivery_cb deliver_skb)
>> +			u8 iphc0, u8 iphc1)
>>  {
>>  	struct ipv6hdr hdr = {};
>>  	u8 tmp, num_context = 0;
>>  	int err;
>> +	int err_ret = -EINVAL;
> use err here, I saw this in your cover-letter as change but it's not
> really changed.
oops, don't know what happened here I did change it.
>
>> +	struct sk_buff *skb = *skb_inout;
>>  
>>  	raw_dump_table(__func__, "raw skb data dump uncompressed",
>>  		       skb->data, skb->len);
>> @@ -460,7 +431,6 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>>  	/* UDP data uncompression */
>>  	if (iphc0 & LOWPAN_IPHC_NH_C) {
>>  		struct udphdr uh;
>> -		struct sk_buff *new;
>>  
>>  		if (uncompress_udp_header(skb, &uh))
>>  			goto drop;
>> @@ -468,14 +438,15 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>>  		/* replace the compressed UDP head by the uncompressed UDP
>>  		 * header
>>  		 */
>> -		new = skb_copy_expand(skb, sizeof(struct udphdr),
>> +		skb = skb_copy_expand(skb, sizeof(struct udphdr),
>>  				      skb_tailroom(skb), GFP_ATOMIC);
>> -		kfree_skb(skb);
>> -
>> -		if (!new)
>> -			return -ENOMEM;
>> +		if (!skb) {
>> +			err_ret = -ENOMEM;
>> +			goto drop;
>> +		}
>>  
>> -		skb = new;
>> +		kfree_skb(*skb_inout);
>> +		*skb_inout = skb;
>>  
>>  		skb_push(skb, sizeof(struct udphdr));
>>  		skb_reset_transport_header(skb);
>> @@ -499,11 +470,27 @@ int lowpan_process_data(struct sk_buff *skb, struct net_device *dev,
>>  
>>  	raw_dump_table(__func__, "raw header dump", (u8 *)&hdr, sizeof(hdr));
>>  
>> -	return skb_deliver(skb, &hdr, dev, deliver_skb);
>> +	/* Setup skb with new uncompressed IPv6 header. */
>> +	skb = skb_copy_expand(skb, sizeof(hdr), skb_tailroom(skb),
>> +			      GFP_ATOMIC);
>> +	if (!skb)
>> +		return -ENOMEM;
>> +
>> +	kfree_skb(*skb_inout);
>> +	*skb_inout = skb;
>> +
>> +	skb_push(skb, sizeof(hdr));
>> +	skb_reset_network_header(skb);
>> +	skb_copy_to_linear_data(skb, &hdr, sizeof(hdr));
>> +	skb->dev = dev;
>> +
>> +	raw_dump_table(__func__, "raw skb data dump before receiving",
>> +		       skb->data, skb->len);
>> +
>> +	return 0;
>>  
>>  drop:
>> -	kfree_skb(skb);
>> -	return -EINVAL;
>> +	return err_ret;
>>  }
>>  EXPORT_SYMBOL_GPL(lowpan_process_data);
>>  
>> diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
>> index 206b65c..a4e340e 100644
>> --- a/net/bluetooth/6lowpan.c
>> +++ b/net/bluetooth/6lowpan.c
>> @@ -215,7 +215,7 @@ static int give_skb_to_upper(struct sk_buff *skb, struct net_device *dev)
>>  	return ret;
>>  }
>>  
>> -static int process_data(struct sk_buff *skb, struct net_device *netdev,
>> +static int process_data(struct sk_buff **skb_inout, struct net_device *netdev,
>>  			struct l2cap_chan *chan)
>>  {
>>  	const u8 *saddr, *daddr;
>> @@ -223,6 +223,7 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
>>  	struct lowpan_dev *dev;
>>  	struct lowpan_peer *peer;
>>  	unsigned long flags;
>> +	struct sk_buff *skb = *skb_inout;
>>  
>>  	dev = lowpan_dev(netdev);
>>  
>> @@ -245,13 +246,12 @@ static int process_data(struct sk_buff *skb, struct net_device *netdev,
>>  	if (lowpan_fetch_skb_u8(skb, &iphc1))
>>  		goto drop;
>>  
>> -	return lowpan_process_data(skb, netdev,
>> +	return lowpan_process_data(skb_inout, netdev,
>>  				   saddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
>>  				   daddr, IEEE802154_ADDR_LONG, EUI64_ADDR_LEN,
>> -				   iphc0, iphc1, give_skb_to_upper);
>> +				   iphc0, iphc1);
>>  
>>  drop:
>> -	kfree_skb(skb);
>>  	return -EINVAL;
>>  }
>>  
>> @@ -280,9 +280,6 @@ 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) {
>>  			kfree_skb(local_skb);
>>  			goto drop;
>> @@ -300,9 +297,20 @@ static int recv_pkt(struct sk_buff *skb, struct net_device *dev,
>>  			if (!local_skb)
>>  				goto drop;
>>  
>> -			ret = process_data(local_skb, dev, chan);
>> -			if (ret != NET_RX_SUCCESS)
>> +			ret = process_data(&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;
>> +
>> +			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++;
>> diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
>> index 6591d27..d5bdeba 100644
>> --- a/net/ieee802154/6lowpan_rtnl.c
>> +++ b/net/ieee802154/6lowpan_rtnl.c
>> @@ -167,11 +167,13 @@ static int lowpan_give_skb_to_devices(struct sk_buff *skb,
>>  	return stat;
>>  }
>>  
>> -static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
>> +static int process_data(struct sk_buff **skb_inout,
>> +			const struct ieee802154_hdr *hdr)
>>  {
>>  	u8 iphc0, iphc1;
>>  	struct ieee802154_addr_sa sa, da;
>>  	void *sap, *dap;
>> +	struct sk_buff *skb = *skb_inout;
>>  
>>  	raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
>>  	/* at least two bytes will be used for the encoding */
>> @@ -197,13 +199,11 @@ static int process_data(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
>>  	else
>>  		dap = &da.hwaddr;
>>  
>> -	return lowpan_process_data(skb, skb->dev, sap, sa.addr_type,
>> +	return lowpan_process_data(skb_inout, skb->dev, sap, sa.addr_type,
>>  				   IEEE802154_ADDR_LEN, dap, da.addr_type,
>> -				   IEEE802154_ADDR_LEN, iphc0, iphc1,
>> -				   lowpan_give_skb_to_devices);
>> +				   IEEE802154_ADDR_LEN, iphc0, iphc1);
>>  
>>  drop:
>> -	kfree_skb(skb);
>>  	return -EINVAL;
>>  }
>>  
>> @@ -478,36 +478,35 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>>  
>>  	/* check that it's our buffer */
>>  	if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
>> -		skb->protocol = htons(ETH_P_IPV6);
>> -		skb->pkt_type = PACKET_HOST;
>> -
>>  		/* Pull off the 1-byte of 6lowpan header. */
>>  		skb_pull(skb, 1);
>>  
>> -		ret = lowpan_give_skb_to_devices(skb, NULL);
>> -		if (ret == NET_RX_DROP)
>> -			goto drop;
>> +		ret = NET_RX_SUCCESS;
>>  	} else {
>>  		switch (skb->data[0] & 0xe0) {
>>  		case LOWPAN_DISPATCH_IPHC:	/* ipv6 datagram */
>> -			ret = process_data(skb, &hdr);
>> -			if (ret == NET_RX_DROP)
>> +			ret = process_data(&skb, &hdr);
>> +			if (ret < 0)
>>  				goto drop;
>>  			break;
>>  		case LOWPAN_DISPATCH_FRAG1:	/* first fragment header */
>>  			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
> can also return "-1" for error but in this case the skb is already freed.
> so some else if with NET_RX_DROP. I know it was not handled before but we
> should handle this right now, when we care about the error handling.
Agreed, will add.
>
>>  			if (ret == 1) {
>> -				ret = process_data(skb, &hdr);
>> -				if (ret == NET_RX_DROP)
>> +				ret = process_data(&skb, &hdr);
>> +				if (ret < 0)
>>  					goto drop;
> this function returning an errno, you can't return the errno here. goto
> drop returns the ret variable. Maybe just make a return NET_RX_DROP at
> drop. We should never return a different variable.
It won't, the drop label will return NET_RX_DROP. 
>
> Also this need to be drop_skb at several places in this code, we don't
> have a kfree_skb at process_data anymore. This leaks memory.
Yep, I think these have been lost in my merge to bluetooth tree :(

>
>> +			} else {
>> +				return NET_RX_SUCCESS;
>>  			}
>>  			break;
>>  		case LOWPAN_DISPATCH_FRAGN:	/* next fragments headers */
>>  			ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
> same here.
>>  			if (ret == 1) {
>> -				ret = process_data(skb, &hdr);
>> -				if (ret == NET_RX_DROP)
>> +				ret = process_data(&skb, &hdr);
>> +				if (ret < 0)
>>  					goto drop;
> same here.
>
>> +			} else {
>> +				return NET_RX_SUCCESS;
>>  			}
>>  			break;
>>  		default:
>> @@ -515,7 +514,16 @@ static int lowpan_rcv(struct sk_buff *skb, struct net_device *dev,
>>  		}
>>  	}
>>  
>> -	return NET_RX_SUCCESS;
>> +	/* Pass IPv6 packet up to next layer */
>> +	skb->protocol = htons(ETH_P_IPV6);
>> +	skb->pkt_type = PACKET_HOST;
>> +	ret = lowpan_give_skb_to_devices(skb, NULL);
> grml, see possible merge conflicts here. In next should be no dev
> parameter anymore. Nevertheless should easy to fix it.
>
>> +	if (ret < 0)
>> +		goto drop_skb;
>> +
> Also here that's too broken here. In lowpan_give_skb_to_devices we have
> mixed errno and  NET_RX_SUCCESS for the return variable, we need to
> clean this up. Maybe just return the NET_RX_SUCCESS|NET_RX_DROP return
> value from netif_rx call.
ok, shall i just do a
return lowpan_give_skb_to_devices(skb);

and then add the code from freeing or consuming the skb in lowpan_give_skb_to_devices?

>> +	kfree_skb(skb);
> consume_skb here.
ok
>
> Simple on error kfree_skb, not a error consume_skb or dev_kfree_skb. I
> prefer consume_skb.
>
> - Alex
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- Martin.

Re: [PATCH v2 bluetooth] 6lowpan: fix incorrect return values in lowpan_rcv

[Alexander Aring]

On Mon, Sep 15, 2014 at 12:08:35PM +0100, Martin Townsend wrote:
> Hi Alex,
> 
...
> > Also here that's too broken here. In lowpan_give_skb_to_devices we have
> > mixed errno and  NET_RX_SUCCESS for the return variable, we need to
> > clean this up. Maybe just return the NET_RX_SUCCESS|NET_RX_DROP return
> > value from netif_rx call.
> ok, shall i just do a
> return lowpan_give_skb_to_devices(skb);
> 
> and then add the code from freeing or consuming the skb in lowpan_give_skb_to_devices?
> 

yes, great idea.

- Alex