[PATCH net-next v2 0/6] 802154: some cleanups and fixes

[PATCH net-next v2 0/6] 802154: some cleanups and fixes

[Phoebe Buckheister]

This series adds some definitions for 802.15.4 header fields that were missing,
changes 6lowpan fragmentation to be aware of security headers and fixes
802.15.4 datagram socket sendmsg(), which was entirely incompliant to date.
Also a few minor changes to mac_cb handling, mark a single-use function static,
and correctly check for EMSGSIZE conditions during wpan_header_create.

Changes since v1:
  * rename mac_cb_alloc to mac_cb_init
  * catch all error cases of sendmsg() instead of only !conn && msg_name
  * redo 6lowpan fragmentation to not clone lower layer headers

---

Phoebe Buckheister (6):
      ieee802154: add definitions for link-layer security and header functions
      mac802154: account for all header parts during wpan header creationg
      ieee802154: change _cb handling slightly
      6lowpan: fix fragmentation
      ieee802154: fix dgram socket sendmsg()
      mac802154: make mac802154_wpan_open static


 include/net/ieee802154.h        |    9 ++
 include/net/ieee802154_netdev.h |   54 ++++++----
 net/ieee802154/6lowpan_rtnl.c   |  207 ++++++++++++++++++++-------------------
 net/ieee802154/dgram.c          |   38 ++++---
 net/ieee802154/header_ops.c     |   52 ++++++++--
 net/mac802154/rx.c              |    2 -
 net/mac802154/wpan.c            |   30 +++---
 7 files changed, 236 insertions(+), 156 deletions(-)



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[PATCH net-next 1/6] ieee802154: add definitions for link-layer security and header functions

[Phoebe Buckheister]

When dealing with 802.15.4, one often has to know the maximum payload
size for a given packet. This depends on many factors, one of which is
whether or not a security header is present in the frame. These
definitions and functions provide an easy way for any upper layer to
calculate the maximum payload size for a packet. The first obvious user
for this is 6lowpan, which duplicates this calculation and gets it
partially wrong because it ignores security headers.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
---
 include/net/ieee802154.h        |    9 +++++++
 include/net/ieee802154_netdev.h |   29 ++++++++++++++++++++++
 net/ieee802154/header_ops.c     |   52 +++++++++++++++++++++++++++++++++------
 3 files changed, 83 insertions(+), 7 deletions(-)

diff --git a/include/net/ieee802154.h b/include/net/ieee802154.h
index c7ae0ac..0aa7122 100644
--- a/include/net/ieee802154.h
+++ b/include/net/ieee802154.h
@@ -79,6 +79,15 @@
 #define IEEE802154_SCF_KEY_SHORT_INDEX		2
 #define IEEE802154_SCF_KEY_HW_INDEX		3
 
+#define IEEE802154_SCF_SECLEVEL_NONE		0
+#define IEEE802154_SCF_SECLEVEL_MIC32		1
+#define IEEE802154_SCF_SECLEVEL_MIC64		2
+#define IEEE802154_SCF_SECLEVEL_MIC128		3
+#define IEEE802154_SCF_SECLEVEL_ENC		4
+#define IEEE802154_SCF_SECLEVEL_ENC_MIC32	5
+#define IEEE802154_SCF_SECLEVEL_ENC_MIC64	6
+#define IEEE802154_SCF_SECLEVEL_ENC_MIC128	7
+
 /* MAC footer size */
 #define IEEE802154_MFR_SIZE	2 /* 2 octets */
 
diff --git a/include/net/ieee802154_netdev.h b/include/net/ieee802154_netdev.h
index 5a719ca..6e4d3e1 100644
--- a/include/net/ieee802154_netdev.h
+++ b/include/net/ieee802154_netdev.h
@@ -27,6 +27,7 @@
 #ifndef IEEE802154_NETDEVICE_H
 #define IEEE802154_NETDEVICE_H
 
+#include <net/ieee802154.h>
 #include <net/af_ieee802154.h>
 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
@@ -114,6 +115,34 @@ int ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr);
 int ieee802154_hdr_peek_addrs(const struct sk_buff *skb,
 			      struct ieee802154_hdr *hdr);
 
+/* parses the full 802.15.4 header a given skb and stores them into hdr,
+ * performing pan id decompression and length checks to be suitable for use in
+ * header_ops.parse
+ */
+int ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr);
+
+int ieee802154_max_payload(const struct ieee802154_hdr *hdr);
+
+static inline int
+ieee802154_sechdr_authtag_len(const struct ieee802154_sechdr *sec)
+{
+	switch (sec->level) {
+	case IEEE802154_SCF_SECLEVEL_MIC32:
+	case IEEE802154_SCF_SECLEVEL_ENC_MIC32:
+		return 4;
+	case IEEE802154_SCF_SECLEVEL_MIC64:
+	case IEEE802154_SCF_SECLEVEL_ENC_MIC64:
+		return 8;
+	case IEEE802154_SCF_SECLEVEL_MIC128:
+	case IEEE802154_SCF_SECLEVEL_ENC_MIC128:
+		return 16;
+	case IEEE802154_SCF_SECLEVEL_NONE:
+	case IEEE802154_SCF_SECLEVEL_ENC:
+	default:
+		return 0;
+	}
+}
+
 static inline int ieee802154_hdr_length(struct sk_buff *skb)
 {
 	struct ieee802154_hdr hdr;
diff --git a/net/ieee802154/header_ops.c b/net/ieee802154/header_ops.c
index bed42a4..c09294e 100644
--- a/net/ieee802154/header_ops.c
+++ b/net/ieee802154/header_ops.c
@@ -195,15 +195,16 @@ ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr)
 	return pos;
 }
 
+static int ieee802154_sechdr_lengths[4] = {
+	[IEEE802154_SCF_KEY_IMPLICIT] = 5,
+	[IEEE802154_SCF_KEY_INDEX] = 6,
+	[IEEE802154_SCF_KEY_SHORT_INDEX] = 10,
+	[IEEE802154_SCF_KEY_HW_INDEX] = 14,
+};
+
 static int ieee802154_hdr_sechdr_len(u8 sc)
 {
-	switch (IEEE802154_SCF_KEY_ID_MODE(sc)) {
-	case IEEE802154_SCF_KEY_IMPLICIT: return 5;
-	case IEEE802154_SCF_KEY_INDEX: return 6;
-	case IEEE802154_SCF_KEY_SHORT_INDEX: return 10;
-	case IEEE802154_SCF_KEY_HW_INDEX: return 14;
-	default: return -EINVAL;
-	}
+	return ieee802154_sechdr_lengths[IEEE802154_SCF_KEY_ID_MODE(sc)];
 }
 
 static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr)
@@ -285,3 +286,40 @@ ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr)
 	return pos;
 }
 EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs);
+
+int
+ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr)
+{
+	const u8 *buf = skb_mac_header(skb);
+	int pos;
+
+	pos = ieee802154_hdr_peek_addrs(skb, hdr);
+	if (pos < 0)
+		return -EINVAL;
+
+	if (hdr->fc.security_enabled) {
+		u8 key_id_mode = IEEE802154_SCF_KEY_ID_MODE(*(buf + pos));
+		int want = pos + ieee802154_sechdr_lengths[key_id_mode];
+
+		if (buf + want > skb_tail_pointer(skb))
+			return -EINVAL;
+
+		pos += ieee802154_hdr_get_sechdr(buf + pos, &hdr->sec);
+	}
+
+	return pos;
+}
+EXPORT_SYMBOL_GPL(ieee802154_hdr_peek);
+
+int ieee802154_max_payload(const struct ieee802154_hdr *hdr)
+{
+	int hlen = ieee802154_hdr_minlen(hdr);
+
+	if (hdr->fc.security_enabled) {
+		hlen += ieee802154_sechdr_lengths[hdr->sec.key_id_mode] - 1;
+		hlen += ieee802154_sechdr_authtag_len(&hdr->sec);
+	}
+
+	return IEEE802154_MTU - hlen - IEEE802154_MFR_SIZE;
+}
+EXPORT_SYMBOL_GPL(ieee802154_max_payload);
-- 
1.7.9.5

[PATCH net-next 2/6] mac802154: account for all header parts during wpan header creationg

[Phoebe Buckheister]

The current WPAN header creation code checks for EMSGSIZE conditions,
but does not account for the MIC field that link layer security may add
at the end of the frame. Now that we can accurately calculate the
maximum payload size of packets, use that to check for EMSGSIZE
conditions.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister-mPn0NPGs4xGatNDF+KUbs4QuADTiUCJX@public.gmane.org>
---
 net/mac802154/wpan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index 1df7a6a..cb34064 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -231,7 +231,7 @@ static int mac802154_header_create(struct sk_buff *skb,
 	skb_reset_mac_header(skb);
 	skb->mac_len = hlen;
 
-	if (hlen + len + 2 > dev->mtu)
+	if (len > ieee802154_max_payload(&hdr))
 		return -EMSGSIZE;
 
 	return hlen;
-- 
1.7.9.5


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[PATCH net-next 4/6] 6lowpan: fix fragmentation

[Phoebe Buckheister]

Currently, 6lowpan creates one 802.15.4 MAC header for the original
packet the device was given by upper layers and reuses this header for
all fragments, if fragmentation is required. This also reuses frame
sequence numbers, which must not happen. 6lowpan also has issues with
fragmentation in the presence of security headers, since those may imply
the presence of trailing fields that are not accounted for by the
fragmentation code right now.

Fix both of these issues by properly allocating fragment skbs with
headromm and tailroom as specified by the underlying device, create one
header for each skb instead of reusing the original header, let the
underlying device do the rest.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister-mPn0NPGs4xGatNDF+KUbs4QuADTiUCJX@public.gmane.org>
---
 net/ieee802154/6lowpan_rtnl.c |  198 ++++++++++++++++++++++-------------------
 1 file changed, 104 insertions(+), 94 deletions(-)

diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index d0191c5..1ae8a56 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -220,139 +220,149 @@ static int lowpan_set_address(struct net_device *dev, void *p)
 	return 0;
 }
 
-static int
-lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
-		     int mlen, int plen, int offset, int type)
+static struct sk_buff*
+lowpan_alloc_frag(struct sk_buff *skb, int size,
+		  const struct ieee802154_hdr *master_hdr)
 {
+	struct net_device *real_dev = lowpan_dev_info(skb->dev)->real_dev;
 	struct sk_buff *frag;
-	int hlen;
-
-	hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
-			LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;
-
-	raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
+	int rc;
+
+	frag = alloc_skb(real_dev->hard_header_len +
+			 real_dev->needed_tailroom + size,
+			 GFP_ATOMIC);
+
+	if (likely(frag)) {
+		frag->dev = real_dev;
+		frag->priority = skb->priority;
+		skb_reserve(frag, real_dev->hard_header_len);
+		skb_reset_network_header(frag);
+		*mac_cb(frag) = *mac_cb(skb);
+
+		rc = dev_hard_header(frag, real_dev, 0, &master_hdr->dest,
+				     &master_hdr->source, size);
+		if (rc < 0) {
+			kfree_skb(frag);
+			return ERR_PTR(-rc);
+		}
+	} else {
+		frag = ERR_PTR(ENOMEM);
+	}
 
-	frag = netdev_alloc_skb(skb->dev,
-				hlen + mlen + plen + IEEE802154_MFR_SIZE);
-	if (!frag)
-		return -ENOMEM;
+	return frag;
+}
 
-	frag->priority = skb->priority;
+static int
+lowpan_xmit_fragment(struct sk_buff *skb, const struct ieee802154_hdr *wpan_hdr,
+		     u8 *frag_hdr, int frag_hdrlen,
+		     int offset, int len)
+{
+	struct sk_buff *frag;
 
-	/* copy header, MFR and payload */
-	skb_put(frag, mlen);
-	skb_copy_to_linear_data(frag, skb_mac_header(skb), mlen);
+	raw_dump_inline(__func__, " fragment header", frag_hdr, frag_hdrlen);
 
-	skb_put(frag, hlen);
-	skb_copy_to_linear_data_offset(frag, mlen, head, hlen);
+	frag = lowpan_alloc_frag(skb, frag_hdrlen + len, wpan_hdr);
+	if (IS_ERR(frag))
+		return -PTR_ERR(frag);
 
-	skb_put(frag, plen);
-	skb_copy_to_linear_data_offset(frag, mlen + hlen,
-				       skb_network_header(skb) + offset, plen);
+	memcpy(skb_put(frag, frag_hdrlen), frag_hdr, frag_hdrlen);
+	memcpy(skb_put(frag, len), skb_network_header(skb) + offset, len);
 
-	raw_dump_table(__func__, " raw fragment dump", frag->data, frag->len);
+	raw_dump_table(__func__, " fragment dump", frag->data, frag->len);
 
 	return dev_queue_xmit(frag);
 }
 
 static int
-lowpan_skb_fragmentation(struct sk_buff *skb, struct net_device *dev)
+lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *dev,
+		       const struct ieee802154_hdr *wpan_hdr)
 {
-	int err;
-	u16 dgram_offset, dgram_size, payload_length, header_length,
-	    lowpan_size, frag_plen, offset;
-	__be16 tag;
-	u8 head[5];
-
-	header_length = skb->mac_len;
-	payload_length = skb->len - header_length;
-	tag = lowpan_dev_info(dev)->fragment_tag++;
-	lowpan_size = skb_network_header_len(skb);
+	u16 dgram_size, dgram_offset;
+	__be16 frag_tag;
+	u8 frag_hdr[5];
+	int frag_cap, frag_len, payload_cap, rc;
+	int skb_unprocessed, skb_offset;
+
 	dgram_size = lowpan_uncompress_size(skb, &dgram_offset) -
-		     header_length;
+		     skb->mac_len;
+	frag_tag = lowpan_dev_info(dev)->fragment_tag++;
 
-	/* first fragment header */
-	head[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x7);
-	head[1] = dgram_size & 0xff;
-	memcpy(head + 2, &tag, sizeof(tag));
+	frag_hdr[0] = LOWPAN_DISPATCH_FRAG1 | ((dgram_size >> 8) & 0x07);
+	frag_hdr[1] = dgram_size & 0xff;
+	memcpy(frag_hdr + 2, &frag_tag, sizeof(frag_tag));
 
-	/* calc the nearest payload length(divided to 8) for first fragment
-	 * which fits into a IEEE802154_MTU
-	 */
-	frag_plen = round_down(IEEE802154_MTU - header_length -
-			       LOWPAN_FRAG1_HEAD_SIZE - lowpan_size -
-			       IEEE802154_MFR_SIZE, 8);
-
-	err = lowpan_fragment_xmit(skb, head, header_length,
-				   frag_plen + lowpan_size, 0,
-				   LOWPAN_DISPATCH_FRAG1);
-	if (err) {
-		pr_debug("%s unable to send FRAG1 packet (tag: %d)",
-			 __func__, tag);
-		goto exit;
-	}
+	payload_cap = ieee802154_max_payload(wpan_hdr);
 
-	offset = lowpan_size + frag_plen;
-	dgram_offset += frag_plen;
+	frag_len = round_down(payload_cap - LOWPAN_FRAG1_HEAD_SIZE -
+			      skb_network_header_len(skb), 8);
 
-	/* next fragment header */
-	head[0] &= ~LOWPAN_DISPATCH_FRAG1;
-	head[0] |= LOWPAN_DISPATCH_FRAGN;
+	skb_offset = skb_network_header_len(skb);
+	skb_unprocessed = skb->len - skb->mac_len - skb_offset;
 
-	frag_plen = round_down(IEEE802154_MTU - header_length -
-			       LOWPAN_FRAGN_HEAD_SIZE - IEEE802154_MFR_SIZE, 8);
+	rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
+				  LOWPAN_FRAG1_HEAD_SIZE, 0,
+				  frag_len + skb_network_header_len(skb));
+	if (rc) {
+		pr_debug("%s unable to send FRAG1 packet (tag: %d)",
+			 __func__, frag_tag);
+		goto err;
+	}
 
-	while (payload_length - offset > 0) {
-		int len = frag_plen;
+	frag_hdr[0] &= ~LOWPAN_DISPATCH_FRAG1;
+	frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
+	frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
 
-		head[4] = dgram_offset >> 3;
+	while (skb_unprocessed >= frag_cap) {
+		dgram_offset += frag_len;
+		skb_offset += frag_len;
+		skb_unprocessed -= frag_len;
+		frag_len = min(frag_cap, skb_unprocessed);
 
-		if (payload_length - offset < len)
-			len = payload_length - offset;
+		frag_hdr[4] = dgram_offset >> 3;
 
-		err = lowpan_fragment_xmit(skb, head, header_length, len,
-					   offset, LOWPAN_DISPATCH_FRAGN);
-		if (err) {
+		rc = lowpan_xmit_fragment(skb, wpan_hdr, frag_hdr,
+					  LOWPAN_FRAGN_HEAD_SIZE, skb_offset,
+					  frag_len);
+		if (rc) {
 			pr_debug("%s unable to send a FRAGN packet. (tag: %d, offset: %d)\n",
-				 __func__, tag, offset);
-			goto exit;
+				 __func__, frag_tag, skb_offset);
+			goto err;
 		}
-
-		offset += len;
-		dgram_offset += len;
 	}
 
-exit:
-	return err;
+	consume_skb(skb);
+	return NET_XMIT_SUCCESS;
+
+err:
+	kfree_skb(skb);
+	return rc;
 }
 
 static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
 {
-	int err = -1;
+	struct ieee802154_hdr wpan_hdr;
+	int max_single;
 
 	pr_debug("package xmit\n");
 
-	skb->dev = lowpan_dev_info(dev)->real_dev;
-	if (skb->dev == NULL) {
-		pr_debug("ERROR: no real wpan device found\n");
-		goto error;
+	if (ieee802154_hdr_peek(skb, &wpan_hdr) < 0) {
+		kfree_skb(skb);
+		return NET_XMIT_DROP;
 	}
 
-	/* Send directly if less than the MTU minus the 2 checksum bytes. */
-	if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
-		err = dev_queue_xmit(skb);
-		goto out;
-	}
+	max_single = ieee802154_max_payload(&wpan_hdr);
 
-	pr_debug("frame is too big, fragmentation is needed\n");
-	err = lowpan_skb_fragmentation(skb, dev);
-error:
-	dev_kfree_skb(skb);
-out:
-	if (err)
-		pr_debug("ERROR: xmit failed\n");
+	if (skb_tail_pointer(skb) - skb_network_header(skb) <= max_single) {
+		skb->dev = lowpan_dev_info(dev)->real_dev;
+		return dev_queue_xmit(skb);
+	} else {
+		netdev_tx_t rc;
+
+		pr_debug("frame is too big, fragmentation is needed\n");
+		rc = lowpan_xmit_fragmented(skb, dev, &wpan_hdr);
 
-	return (err < 0) ? NET_XMIT_DROP : err;
+		return rc < 0 ? NET_XMIT_DROP : rc;
+	}
 }
 
 static struct wpan_phy *lowpan_get_phy(const struct net_device *dev)
-- 
1.7.9.5


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Re: [Linux-zigbee-devel] [PATCH net-next 4/6] 6lowpan: fix fragmentation

[Alexander Aring]

Hi Phoebe,

that's a nice solution for the DSN increment on fragmentation. This
stands long time on my ToDo list and you did a very nice solution.

Thanks. :-)

On Wed, May 14, 2014 at 05:43:09PM +0200, Phoebe Buckheister wrote:
> Currently, 6lowpan creates one 802.15.4 MAC header for the original
> packet the device was given by upper layers and reuses this header for
> all fragments, if fragmentation is required. This also reuses frame
> sequence numbers, which must not happen. 6lowpan also has issues with
> fragmentation in the presence of security headers, since those may imply
> the presence of trailing fields that are not accounted for by the
> fragmentation code right now.
> 
> Fix both of these issues by properly allocating fragment skbs with
> headromm and tailroom as specified by the underlying device, create one
> header for each skb instead of reusing the original header, let the
> underlying device do the rest.
> 
> Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
> ---
>  net/ieee802154/6lowpan_rtnl.c |  198 ++++++++++++++++++++++-------------------
>  1 file changed, 104 insertions(+), 94 deletions(-)
> 
> diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
> index d0191c5..1ae8a56 100644
> --- a/net/ieee802154/6lowpan_rtnl.c
> +++ b/net/ieee802154/6lowpan_rtnl.c
> @@ -220,139 +220,149 @@ static int lowpan_set_address(struct net_device *dev, void *p)
>  	return 0;
>  }
>  
> -static int
> -lowpan_fragment_xmit(struct sk_buff *skb, u8 *head,
> -		     int mlen, int plen, int offset, int type)
> +static struct sk_buff*
> +lowpan_alloc_frag(struct sk_buff *skb, int size,
> +		  const struct ieee802154_hdr *master_hdr)
>  {
> +	struct net_device *real_dev = lowpan_dev_info(skb->dev)->real_dev;
>  	struct sk_buff *frag;
> -	int hlen;
> -
> -	hlen = (type == LOWPAN_DISPATCH_FRAG1) ?
> -			LOWPAN_FRAG1_HEAD_SIZE : LOWPAN_FRAGN_HEAD_SIZE;
> -
> -	raw_dump_inline(__func__, "6lowpan fragment header", head, hlen);
> +	int rc;
> +
> +	frag = alloc_skb(real_dev->hard_header_len +
> +			 real_dev->needed_tailroom + size,
> +			 GFP_ATOMIC);

Why not keep netdev_alloc_skb for the real_dev?

But then we need to use dev_kfree_skb.

- Alex

Re: [Linux-zigbee-devel] [PATCH net-next 4/6] 6lowpan: fix fragmentation

[Phoebe Buckheister]

On Wed, 14 May 2014 17:56:57 +0200
Alexander Aring <alex.aring@gmail.com> wrote:

> > +
> > +	frag = alloc_skb(real_dev->hard_header_len +
> > +			 real_dev->needed_tailroom + size,
> > +			 GFP_ATOMIC);
> 
> Why not keep netdev_alloc_skb for the real_dev?
> 
> But then we need to use dev_kfree_skb.

Because netdev_alloc_skb allocates "for RX", which uses different
allocation flags internally and might do the wrong thing when memory
is tight.

Also, all skb free funtions are essentially the same, where
dev_kfree_skb == kfree_skb by a macro definition, and what remains
differs pretty much only in how it shows up in traces. They all call
__kfree_skb internally.

> 
> - Alex

[PATCH net-next 3/6] ieee802154: change _cb handling slightly

[Phoebe Buckheister]

The current mac_cb handling of ieee802154 is rather awkward and limited.
Decompose the single flags field into multiple fields with the meanings
of each subfield of the flags field to make future extensions (for
example, link-layer security) easier. Also don't set the frame sequence
number in upper layers, since that's a thing the MAC is supposed to set
on frame transmit - we set it on header creation, but assuming that
upper layers do not blindly duplicate our headers, this is fine.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
---
 include/net/ieee802154_netdev.h |   25 +++++++------------------
 net/ieee802154/6lowpan_rtnl.c   |    9 ++++-----
 net/ieee802154/dgram.c          |   10 ++++------
 net/mac802154/rx.c              |    2 --
 net/mac802154/wpan.c            |   26 +++++++++++++-------------
 5 files changed, 28 insertions(+), 44 deletions(-)

diff --git a/include/net/ieee802154_netdev.h b/include/net/ieee802154_netdev.h
index 6e4d3e1..bc9a747 100644
--- a/include/net/ieee802154_netdev.h
+++ b/include/net/ieee802154_netdev.h
@@ -222,8 +222,9 @@ static inline void ieee802154_addr_to_sa(struct ieee802154_addr_sa *sa,
  */
 struct ieee802154_mac_cb {
 	u8 lqi;
-	u8 flags;
-	u8 seq;
+	u8 type;
+	bool ackreq;
+	bool secen;
 	struct ieee802154_addr source;
 	struct ieee802154_addr dest;
 };
@@ -233,24 +234,12 @@ static inline struct ieee802154_mac_cb *mac_cb(struct sk_buff *skb)
 	return (struct ieee802154_mac_cb *)skb->cb;
 }
 
-#define MAC_CB_FLAG_TYPEMASK		((1 << 3) - 1)
-
-#define MAC_CB_FLAG_ACKREQ		(1 << 3)
-#define MAC_CB_FLAG_SECEN		(1 << 4)
-
-static inline bool mac_cb_is_ackreq(struct sk_buff *skb)
-{
-	return mac_cb(skb)->flags & MAC_CB_FLAG_ACKREQ;
-}
-
-static inline bool mac_cb_is_secen(struct sk_buff *skb)
+static inline struct ieee802154_mac_cb *mac_cb_init(struct sk_buff *skb)
 {
-	return mac_cb(skb)->flags & MAC_CB_FLAG_SECEN;
-}
+	BUILD_BUG_ON(sizeof(struct ieee802154_mac_cb) > sizeof(skb->cb));
 
-static inline int mac_cb_type(struct sk_buff *skb)
-{
-	return mac_cb(skb)->flags & MAC_CB_FLAG_TYPEMASK;
+	memset(skb->cb, 0, sizeof(struct ieee802154_mac_cb));
+	return mac_cb(skb);
 }
 
 #define IEEE802154_MAC_SCAN_ED		0
diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 0f5a69e..d0191c5 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c
@@ -92,6 +92,7 @@ static int lowpan_header_create(struct sk_buff *skb,
 	const u8 *saddr = _saddr;
 	const u8 *daddr = _daddr;
 	struct ieee802154_addr sa, da;
+	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 
 	/* TODO:
 	 * if this package isn't ipv6 one, where should it be routed?
@@ -115,8 +116,7 @@ static int lowpan_header_create(struct sk_buff *skb,
 	 * from MAC subif of the 'dev' and 'real_dev' network devices, but
 	 * this isn't implemented in mainline yet, so currently we assign 0xff
 	 */
-	mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
-	mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
+	cb->type = IEEE802154_FC_TYPE_DATA;
 
 	/* prepare wpan address data */
 	sa.mode = IEEE802154_ADDR_LONG;
@@ -135,11 +135,10 @@ static int lowpan_header_create(struct sk_buff *skb,
 	} else {
 		da.mode = IEEE802154_ADDR_LONG;
 		da.extended_addr = ieee802154_devaddr_from_raw(daddr);
-
-		/* request acknowledgment */
-		mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
 	}
 
+	cb->ackreq = !lowpan_is_addr_broadcast(daddr);
+
 	return dev_hard_header(skb, lowpan_dev_info(dev)->real_dev,
 			type, (void *)&da, (void *)&sa, 0);
 }
diff --git a/net/ieee802154/dgram.c b/net/ieee802154/dgram.c
index 786437b..d95e2e1b 100644
--- a/net/ieee802154/dgram.c
+++ b/net/ieee802154/dgram.c
@@ -209,6 +209,7 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 	struct net_device *dev;
 	unsigned int mtu;
 	struct sk_buff *skb;
+	struct ieee802154_mac_cb *cb;
 	struct dgram_sock *ro = dgram_sk(sk);
 	int hlen, tlen;
 	int err;
@@ -249,18 +250,15 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 
 	skb_reset_network_header(skb);
 
-	mac_cb(skb)->flags = IEEE802154_FC_TYPE_DATA;
-	if (ro->want_ack)
-		mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
+	cb = mac_cb_init(skb);
+	cb->type = IEEE802154_FC_TYPE_DATA;
+	cb->ackreq = ro->want_ack;
 
-	mac_cb(skb)->seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
 	err = dev_hard_header(skb, dev, ETH_P_IEEE802154, &ro->dst_addr,
 			ro->bound ? &ro->src_addr : NULL, size);
 	if (err < 0)
 		goto out_skb;
 
-	skb_reset_mac_header(skb);
-
 	err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
 	if (err < 0)
 		goto out_skb;
diff --git a/net/mac802154/rx.c b/net/mac802154/rx.c
index 03855b0..0597b96 100644
--- a/net/mac802154/rx.c
+++ b/net/mac802154/rx.c
@@ -59,8 +59,6 @@ mac802154_subif_rx(struct ieee802154_dev *hw, struct sk_buff *skb, u8 lqi)
 	skb->protocol = htons(ETH_P_IEEE802154);
 	skb_reset_mac_header(skb);
 
-	BUILD_BUG_ON(sizeof(struct ieee802154_mac_cb) > sizeof(skb->cb));
-
 	if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
 		u16 crc;
 
diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index cb34064..bb49e88 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -192,15 +192,17 @@ static int mac802154_header_create(struct sk_buff *skb,
 {
 	struct ieee802154_hdr hdr;
 	struct mac802154_sub_if_data *priv = netdev_priv(dev);
+	struct ieee802154_mac_cb *cb = mac_cb(skb);
 	int hlen;
 
 	if (!daddr)
 		return -EINVAL;
 
 	memset(&hdr.fc, 0, sizeof(hdr.fc));
-	hdr.fc.type = mac_cb_type(skb);
-	hdr.fc.security_enabled = mac_cb_is_secen(skb);
-	hdr.fc.ack_request = mac_cb_is_ackreq(skb);
+	hdr.fc.type = cb->type;
+	hdr.fc.security_enabled = cb->secen;
+	hdr.fc.ack_request = cb->ackreq;
+	hdr.seq = ieee802154_mlme_ops(dev)->get_dsn(dev);
 
 	if (!saddr) {
 		spin_lock_bh(&priv->mib_lock);
@@ -391,12 +393,12 @@ mac802154_subif_frame(struct mac802154_sub_if_data *sdata, struct sk_buff *skb)
 	sdata->dev->stats.rx_packets++;
 	sdata->dev->stats.rx_bytes += skb->len;
 
-	switch (mac_cb_type(skb)) {
+	switch (mac_cb(skb)->type) {
 	case IEEE802154_FC_TYPE_DATA:
 		return mac802154_process_data(sdata->dev, skb);
 	default:
 		pr_warn("ieee802154: bad frame received (type = %d)\n",
-			mac_cb_type(skb));
+			mac_cb(skb)->type);
 		kfree_skb(skb);
 		return NET_RX_DROP;
 	}
@@ -423,6 +425,7 @@ static int mac802154_parse_frame_start(struct sk_buff *skb)
 {
 	int hlen;
 	struct ieee802154_hdr hdr;
+	struct ieee802154_mac_cb *cb = mac_cb_init(skb);
 
 	hlen = ieee802154_hdr_pull(skb, &hdr);
 	if (hlen < 0)
@@ -433,18 +436,15 @@ static int mac802154_parse_frame_start(struct sk_buff *skb)
 	pr_debug("fc: %04x dsn: %02x\n", le16_to_cpup((__le16 *)&hdr.fc),
 		 hdr.seq);
 
-	mac_cb(skb)->flags = hdr.fc.type;
-
-	if (hdr.fc.ack_request)
-		mac_cb(skb)->flags |= MAC_CB_FLAG_ACKREQ;
-	if (hdr.fc.security_enabled)
-		mac_cb(skb)->flags |= MAC_CB_FLAG_SECEN;
+	cb->type = hdr.fc.type;
+	cb->ackreq = hdr.fc.ack_request;
+	cb->secen = hdr.fc.security_enabled;
 
 	mac802154_print_addr("destination", &hdr.dest);
 	mac802154_print_addr("source", &hdr.source);
 
-	mac_cb(skb)->source = hdr.source;
-	mac_cb(skb)->dest = hdr.dest;
+	cb->source = hdr.source;
+	cb->dest = hdr.dest;
 
 	if (hdr.fc.security_enabled) {
 		u64 key;
-- 
1.7.9.5

[PATCH net-next 5/6] ieee802154: fix dgram socket sendmsg()

[Phoebe Buckheister]

802.15.4 datagram sockets do not currently have a compliant sendmsg().
The destination address supplied is always ignored, and in unconnected
mode, packets are broadcast instead of dropped with -EDESTADDRREQ. This
patch fixes 802.15.4 dgram sockets to be compliant, i.e.

 !conn && !msg_name => -EDESTADDRREQ
 !conn &&  msg_name => send to msg_name
  conn && !msg_name => send to connected
  conn &&  msg_name => -EISCONN

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
---
 net/ieee802154/dgram.c |   28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/net/ieee802154/dgram.c b/net/ieee802154/dgram.c
index d95e2e1b..76c7725 100644
--- a/net/ieee802154/dgram.c
+++ b/net/ieee802154/dgram.c
@@ -45,6 +45,7 @@ struct dgram_sock {
 	struct ieee802154_addr dst_addr;
 
 	unsigned int bound:1;
+	unsigned int connected:1;
 	unsigned int want_ack:1;
 };
 
@@ -73,10 +74,7 @@ static int dgram_init(struct sock *sk)
 {
 	struct dgram_sock *ro = dgram_sk(sk);
 
-	ro->dst_addr.mode = IEEE802154_ADDR_LONG;
-	ro->dst_addr.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
 	ro->want_ack = 1;
-	memset(&ro->dst_addr.extended_addr, 0xff, IEEE802154_ADDR_LEN);
 	return 0;
 }
 
@@ -183,6 +181,7 @@ static int dgram_connect(struct sock *sk, struct sockaddr *uaddr,
 	}
 
 	ieee802154_addr_from_sa(&ro->dst_addr, &addr->addr);
+	ro->connected = 1;
 
 out:
 	release_sock(sk);
@@ -194,10 +193,7 @@ static int dgram_disconnect(struct sock *sk, int flags)
 	struct dgram_sock *ro = dgram_sk(sk);
 
 	lock_sock(sk);
-
-	ro->dst_addr.mode = IEEE802154_ADDR_LONG;
-	memset(&ro->dst_addr.extended_addr, 0xff, IEEE802154_ADDR_LEN);
-
+	ro->connected = 0;
 	release_sock(sk);
 
 	return 0;
@@ -211,6 +207,7 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 	struct sk_buff *skb;
 	struct ieee802154_mac_cb *cb;
 	struct dgram_sock *ro = dgram_sk(sk);
+	struct ieee802154_addr dst_addr;
 	int hlen, tlen;
 	int err;
 
@@ -219,6 +216,11 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 		return -EOPNOTSUPP;
 	}
 
+	if (!ro->connected && !msg->msg_name)
+		return -EDESTADDRREQ;
+	else if (ro->connected && msg->msg_name)
+		return -EISCONN;
+
 	if (!ro->bound)
 		dev = dev_getfirstbyhwtype(sock_net(sk), ARPHRD_IEEE802154);
 	else
@@ -254,8 +256,16 @@ static int dgram_sendmsg(struct kiocb *iocb, struct sock *sk,
 	cb->type = IEEE802154_FC_TYPE_DATA;
 	cb->ackreq = ro->want_ack;
 
-	err = dev_hard_header(skb, dev, ETH_P_IEEE802154, &ro->dst_addr,
-			ro->bound ? &ro->src_addr : NULL, size);
+	if (msg->msg_name) {
+		DECLARE_SOCKADDR(struct sockaddr_ieee802154*, daddr, msg->msg_name);
+
+		ieee802154_addr_from_sa(&dst_addr, &daddr->addr);
+	} else {
+		dst_addr = ro->dst_addr;
+	}
+
+	err = dev_hard_header(skb, dev, ETH_P_IEEE802154, &dst_addr,
+			      ro->bound ? &ro->src_addr : NULL, size);
 	if (err < 0)
 		goto out_skb;
 
-- 
1.7.9.5

[PATCH net-next 6/6] mac802154: make mac802154_wpan_open static

[Phoebe Buckheister]

This function is only used within the same translation unit, so mark it
static.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
---
 net/mac802154/wpan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index bb49e88..ed10577 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -124,7 +124,7 @@ void mac802154_get_mac_params(struct net_device *dev,
 	mutex_unlock(&priv->hw->slaves_mtx);
 }
 
-int mac802154_wpan_open(struct net_device *dev)
+static int mac802154_wpan_open(struct net_device *dev)
 {
 	int rc;
 	struct mac802154_sub_if_data *priv = netdev_priv(dev);
-- 
1.7.9.5

Re: [PATCH net-next v2 0/6] 802154: some cleanups and fixes

[David Miller]

From: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Date: Wed, 14 May 2014 17:43:05 +0200

> This series adds some definitions for 802.15.4 header fields that were missing,
> changes 6lowpan fragmentation to be aware of security headers and fixes
> 802.15.4 datagram socket sendmsg(), which was entirely incompliant to date.
> Also a few minor changes to mac_cb handling, mark a single-use function static,
> and correctly check for EMSGSIZE conditions during wpan_header_create.
> 
> Changes since v1:
>   * rename mac_cb_alloc to mac_cb_init
>   * catch all error cases of sendmsg() instead of only !conn && msg_name
>   * redo 6lowpan fragmentation to not clone lower layer headers

Series applied to net-next, thank you.