[PATCHv2 net-next 0/6] 6lowpan: uncompress of addresses fix

[PATCHv2 net-next 0/6] 6lowpan: uncompress of addresses fix

[Alexander Aring]

The current implementation to uncompress addresses in a 6lowpan header
is completely broken.

This patch series fixes the parsing of addresses in a 6lowpan header.
It contains a major rewrite of the uncompress address function to parse
the address in a correct way.

Changes since v2:
 - Add tags for net-next
 - Change commit msg in Patch 1/6 that this patch depends for the following
   patches

Alexander Aring (5):
  6lowpan: init ipv6hdr buffer to zero
  6lowpan: introduce lowpan_fetch_skb function
  6lowpan: add function to uncompress multicast addr
  6lowpan: lowpan_uncompress_addr with address_mode
  6lowpan: handle context based source address

David Hauweele (1):
  6lowpan: Fix fragmentation with link-local compressed addresses

 net/ieee802154/6lowpan.c | 284 +++++++++++++++++++++++++++++++----------------
 net/ieee802154/6lowpan.h |  20 +++-
 2 files changed, 203 insertions(+), 101 deletions(-)

-- 
1.8.3.3


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[PATCH 1/6] 6lowpan: init ipv6hdr buffer to zero

[Alexander Aring]

This patch simplify the handling to set fields inside of struct ipv6hdr
to zero. Instead of setting some memory regions with memset to zero we
initialize the whole ipv6hdr to zero.

This is a simplification for parsing the 6lowpan header for the upcomming
patches.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 3b9d5f2..92429db 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -223,10 +223,6 @@ lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,
 	if (prefcount > 0)
 		memcpy(ipaddr, prefix, prefcount);
 
-	if (prefcount + postcount < 16)
-		memset(&ipaddr->s6_addr[prefcount], 0,
-					16 - (prefcount + postcount));
-
 	if (postcount > 0) {
 		memcpy(&ipaddr->s6_addr[16 - postcount], skb->data, postcount);
 		skb_pull(skb, postcount);
@@ -723,7 +719,7 @@ frame_err:
 static int
 lowpan_process_data(struct sk_buff *skb)
 {
-	struct ipv6hdr hdr;
+	struct ipv6hdr hdr = {};
 	u8 tmp, iphc0, iphc1, num_context = 0;
 	u8 *_saddr, *_daddr;
 	int err;
@@ -868,8 +864,6 @@ lowpan_process_data(struct sk_buff *skb)
 
 		hdr.priority = ((tmp >> 2) & 0x0f);
 		hdr.flow_lbl[0] = ((tmp << 6) & 0xC0) | ((tmp >> 2) & 0x30);
-		hdr.flow_lbl[1] = 0;
-		hdr.flow_lbl[2] = 0;
 		break;
 	/*
 	 * Flow Label carried in-line
@@ -885,10 +879,6 @@ lowpan_process_data(struct sk_buff *skb)
 		break;
 	/* Traffic Class and Flow Label are elided */
 	case 3: /* 11b */
-		hdr.priority = 0;
-		hdr.flow_lbl[0] = 0;
-		hdr.flow_lbl[1] = 0;
-		hdr.flow_lbl[2] = 0;
 		break;
 	default:
 		break;
-- 
1.8.3.3


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Re: [PATCH 1/6] 6lowpan: init ipv6hdr buffer to zero

[Alexander Aring]

Hi,

I forgot a "net-next" in the subject, sry.
So this patch is for "net-next"

Regards
Alex

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[PATCH net-next 2/6] 6lowpan: Fix fragmentation with link-local compressed addresses

[Alexander Aring]

From: David Hauweele <david-1EggE+PRa6vk1uMJSBkQmQ@public.gmane.org>

When a new 6lowpan fragment is received, a skbuff is allocated for
the reassembled packet. However when a 6lowpan packet compresses
link-local addresses based on link-layer addresses, the processing
function relies on the skb mac control block to find the related
link-layer address.

This patch copies the control block from the first fragment into
the newly allocated skb to keep a trace of the link-layer addresses
in case of a link-local compressed address.

Edit: small changes on comment issue

Signed-off-by: David Hauweele <david-1EggE+PRa6vk1uMJSBkQmQ@public.gmane.org>
Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 92429db..632b3fd 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -698,6 +698,12 @@ lowpan_alloc_new_frame(struct sk_buff *skb, u16 len, u16 tag)
 	skb_reserve(frame->skb, sizeof(struct ipv6hdr));
 	skb_put(frame->skb, frame->length);
 
+	/* copy the first control block to keep a
+	 * trace of the link-layer addresses in case
+	 * of a link-local compressed address
+	 */
+	memcpy(frame->skb->cb, skb->cb, sizeof(skb->cb));
+
 	init_timer(&frame->timer);
 	/* time out is the same as for ipv6 - 60 sec */
 	frame->timer.expires = jiffies + LOWPAN_FRAG_TIMEOUT;
-- 
1.8.3.3


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[PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Alexander Aring]

This patch adds a helper function to parse the ipv6 header to a
6lowpan header in stream.

This function checks first if we can pull data with a specific
length from a skb. If this seems to be okay, we copy skb data to
a destination pointer and run skb_pull.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 61f0ce9..e3348ec 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -233,4 +233,16 @@
 					dest = 16 bit inline */
 #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
 
+static inline bool lowpan_fetch_skb(struct sk_buff *skb,
+		void *data, const unsigned int len)
+{
+	if (unlikely(!pskb_may_pull(skb, len)))
+		return true;
+
+	skb_copy_from_linear_data(skb, data, len);
+	skb_pull(skb, len);
+
+	return false;
+}
+
 #endif /* __6LOWPAN_H__ */
-- 
1.8.3.3


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Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Hannes Frederic Sowa]

On Wed, Aug 14, 2013 at 01:01:45PM +0200, Alexander Aring wrote:
> This patch adds a helper function to parse the ipv6 header to a
> 6lowpan header in stream.
> 
> This function checks first if we can pull data with a specific
> length from a skb. If this seems to be okay, we copy skb data to
> a destination pointer and run skb_pull.
> 
> Signed-off-by: Alexander Aring <alex.aring@gmail.com>
> Reviewed-by: Werner Almesberger <werner@almesberger.net>
> ---
>  net/ieee802154/6lowpan.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
> index 61f0ce9..e3348ec 100644
> --- a/net/ieee802154/6lowpan.h
> +++ b/net/ieee802154/6lowpan.h
> @@ -233,4 +233,16 @@
>  					dest = 16 bit inline */
>  #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
>  
> +static inline bool lowpan_fetch_skb(struct sk_buff *skb,
> +		void *data, const unsigned int len)
> +{
> +	if (unlikely(!pskb_may_pull(skb, len)))
> +		return true;
> +
> +	skb_copy_from_linear_data(skb, data, len);
> +	skb_pull(skb, len);
> +
> +	return false;
> +}

Isn't the return value inverted here?

Greetings,

  Hannes

Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Alexander Smirnov]

On 08/14/2013 03:49 PM, Hannes Frederic Sowa wrote:
> On Wed, Aug 14, 2013 at 01:01:45PM +0200, Alexander Aring wrote:
>> This patch adds a helper function to parse the ipv6 header to a
>> 6lowpan header in stream.
>>
>> This function checks first if we can pull data with a specific
>> length from a skb. If this seems to be okay, we copy skb data to
>> a destination pointer and run skb_pull.
>>
>> Signed-off-by: Alexander Aring <alex.aring@gmail.com>
>> Reviewed-by: Werner Almesberger <werner@almesberger.net>
>> ---
>>   net/ieee802154/6lowpan.h | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
>> index 61f0ce9..e3348ec 100644
>> --- a/net/ieee802154/6lowpan.h
>> +++ b/net/ieee802154/6lowpan.h
>> @@ -233,4 +233,16 @@
>>   					dest = 16 bit inline */
>>   #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
>>
>> +static inline bool lowpan_fetch_skb(struct sk_buff *skb,
>> +		void *data, const unsigned int len)
>> +{
>> +	if (unlikely(!pskb_may_pull(skb, len)))
>> +		return true;
>> +
>> +	skb_copy_from_linear_data(skb, data, len);
>> +	skb_pull(skb, len);
>> +
>> +	return false;
>> +}
>
> Isn't the return value inverted here?

Nope, everything is right here, but I spent several minutes to get it...
Probably using of standard intergers will be better here: return -EINVAL 
and return 0;

>
> Greetings,
>
>    Hannes
>

Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Hannes Frederic Sowa]

On Wed, Aug 14, 2013 at 03:55:21PM +0400, Alexander Smirnov wrote:
> On 08/14/2013 03:49 PM, Hannes Frederic Sowa wrote:
> >On Wed, Aug 14, 2013 at 01:01:45PM +0200, Alexander Aring wrote:
> >>This patch adds a helper function to parse the ipv6 header to a
> >>6lowpan header in stream.
> >>
> >>This function checks first if we can pull data with a specific
> >>length from a skb. If this seems to be okay, we copy skb data to
> >>a destination pointer and run skb_pull.
> >>
> >>Signed-off-by: Alexander Aring <alex.aring@gmail.com>
> >>Reviewed-by: Werner Almesberger <werner@almesberger.net>
> >>---
> >>  net/ieee802154/6lowpan.h | 12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >>
> >>diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
> >>index 61f0ce9..e3348ec 100644
> >>--- a/net/ieee802154/6lowpan.h
> >>+++ b/net/ieee802154/6lowpan.h
> >>@@ -233,4 +233,16 @@
> >>  					dest = 16 bit inline */
> >>  #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit 
> >>  inline */
> >>
> >>+static inline bool lowpan_fetch_skb(struct sk_buff *skb,
> >>+		void *data, const unsigned int len)
> >>+{
> >>+	if (unlikely(!pskb_may_pull(skb, len)))
> >>+		return true;
> >>+
> >>+	skb_copy_from_linear_data(skb, data, len);
> >>+	skb_pull(skb, len);
> >>+
> >>+	return false;
> >>+}
> >
> >Isn't the return value inverted here?
> 
> Nope, everything is right here, but I spent several minutes to get it...
> Probably using of standard intergers will be better here: return -EINVAL 
> and return 0;

Ah, yes, I saw it in your next patch. You could also use false for failure and
true for success. Either way, this seemd a bit unnatural for me.

Thanks,

  Hannes

Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Alexander Aring]

Hi Alex,

On Wed, Aug 14, 2013 at 03:55:21PM +0400, Alexander Smirnov wrote:
> On 08/14/2013 03:49 PM, Hannes Frederic Sowa wrote:
> >On Wed, Aug 14, 2013 at 01:01:45PM +0200, Alexander Aring wrote:
> >>This patch adds a helper function to parse the ipv6 header to a
> >>6lowpan header in stream.
> >>
> >>This function checks first if we can pull data with a specific
> >>length from a skb. If this seems to be okay, we copy skb data to
> >>a destination pointer and run skb_pull.
> >>
> >>Signed-off-by: Alexander Aring <alex.aring@gmail.com>
> >>Reviewed-by: Werner Almesberger <werner@almesberger.net>
> >>---
> >>  net/ieee802154/6lowpan.h | 12 ++++++++++++
> >>  1 file changed, 12 insertions(+)
> >>
> >>diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
> >>index 61f0ce9..e3348ec 100644
> >>--- a/net/ieee802154/6lowpan.h
> >>+++ b/net/ieee802154/6lowpan.h
> >>@@ -233,4 +233,16 @@
> >>  					dest = 16 bit inline */
> >>  #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
> >>
> >>+static inline bool lowpan_fetch_skb(struct sk_buff *skb,
> >>+		void *data, const unsigned int len)
> >>+{
> >>+	if (unlikely(!pskb_may_pull(skb, len)))
> >>+		return true;
> >>+
> >>+	skb_copy_from_linear_data(skb, data, len);
> >>+	skb_pull(skb, len);
> >>+
> >>+	return false;
> >>+}
> >
> >Isn't the return value inverted here?
> 
> Nope, everything is right here, but I spent several minutes to get it...
> Probably using of standard intergers will be better here: return
> -EINVAL and return 0;
> 

This was the old behaviour, we decide it to make it like this:

fail = ...
fail |= ....

if (fail)
	...

We discussed that already at the linux-zigbee-devel mailinglist.
I don't know what I should do now, on linux-zigbee-devel we decide it to
this way, now we decide it in a other way...

Regards
Alex

Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Hannes Frederic Sowa]

On Wed, Aug 14, 2013 at 02:45:47PM +0200, Alexander Aring wrote:
> This was the old behaviour, we decide it to make it like this:
> 
> fail = ...
> fail |= ....
> 
> if (fail)
> 	...
> 
> We discussed that already at the linux-zigbee-devel mailinglist.
> I don't know what I should do now, on linux-zigbee-devel we decide it to
> this way, now we decide it in a other way...

Oh, I didn't know. Please just take my mail as a suggestion. If there
already was a discussion and you had a consensus about that please just
ignore my mails. :)

Thanks,

  Hannes

Re: [PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Alexander Aring]

Hi Hannes,

On Wed, Aug 14, 2013 at 02:47:54PM +0200, Hannes Frederic Sowa wrote:
> On Wed, Aug 14, 2013 at 02:45:47PM +0200, Alexander Aring wrote:
> > This was the old behaviour, we decide it to make it like this:
> > 
> > fail = ...
> > fail |= ....
> > 
> > if (fail)
> > 	...
> > 
> > We discussed that already at the linux-zigbee-devel mailinglist.
> > I don't know what I should do now, on linux-zigbee-devel we decide it to
> > this way, now we decide it in a other way...
> 
> Oh, I didn't know. Please just take my mail as a suggestion. If there
> already was a discussion and you had a consensus about that please just
> ignore my mails. :)
>
This discussion was only with two persons.
So I am happy to hear some other opinions. :-)

Regards
Alex

[PATCH net-next 4/6] 6lowpan: add function to uncompress multicast addr

[Alexander Aring]

Add function to uncompress multicast address.
This function split the uncompress function for a multicast address
in a seperate function.

To uncompress a multicast address is different than a other
non-multicasts addresses according to rfc6282.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.c | 78 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 59 insertions(+), 19 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 632b3fd..0df8874 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -88,15 +88,6 @@ static const u8 lowpan_unc_llconf[] = {0x0f, 0x28, 0x22, 0x20};
  */
 static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};
 
-/*
- * Uncompression of ctx-base
- *   0 -> 0 bits from packet
- *   1 -> 2 bytes from prefix - bunch of zeroes 5 from packet
- *   2 -> 2 bytes from prefix - zeroes + 3 from packet
- *   3 -> 2 bytes from prefix - infer 1 bytes from lladdr
- */
-static const u8 lowpan_unc_mxconf[] = {0x0f, 0x25, 0x23, 0x21};
-
 /* Link local prefix */
 static const u8 lowpan_llprefix[] = {0xfe, 0x80};
 
@@ -240,6 +231,63 @@ lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,
 	return 0;
 }
 
+/* Uncompress function for multicast destination address,
+ * when M bit is set.
+ */
+static int
+lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
+		struct in6_addr *ipaddr,
+		const u8 dam)
+{
+	bool fail;
+
+	switch (dam) {
+	case LOWPAN_IPHC_DAM_00:
+		/* 00:  128 bits.  The full address
+		 * is carried in-line.
+		 */
+		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
+		break;
+	case LOWPAN_IPHC_DAM_01:
+		/* 01:  48 bits.  The address takes
+		 * the form ffXX::00XX:XXXX:XXXX.
+		 */
+		ipaddr->s6_addr[0] = 0xFF;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
+		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[11], 5);
+		break;
+	case LOWPAN_IPHC_DAM_10:
+		/* 10:  32 bits.  The address takes
+		 * the form ffXX::00XX:XXXX.
+		 */
+		ipaddr->s6_addr[0] = 0xFF;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 1);
+		fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[13], 3);
+		break;
+	case LOWPAN_IPHC_DAM_11:
+		/* 11:  8 bits.  The address takes
+		 * the form ff02::00XX.
+		 */
+		ipaddr->s6_addr[0] = 0xFF;
+		ipaddr->s6_addr[1] = 0x02;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[15], 1);
+		break;
+	default:
+		pr_debug("DAM value has a wrong value: 0x%x\n", dam);
+		return -EINVAL;
+	}
+
+	if (fail) {
+		pr_debug("Failed to fetch skb data\n");
+		return -EIO;
+	}
+
+	pr_debug("Reconstructed ipv6 multicast addr is:\n");
+	lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);
+
+	return 0;
+}
+
 static void
 lowpan_compress_udp_header(u8 **hc06_ptr, struct sk_buff *skb)
 {
@@ -927,16 +975,8 @@ lowpan_process_data(struct sk_buff *skb)
 			pr_debug("dest: context-based mcast compression\n");
 			/* TODO: implement this */
 		} else {
-			u8 prefix[] = {0xff, 0x02};
-
-			pr_debug("dest: non context-based mcast compression\n");
-			if (0 < tmp && tmp < 3) {
-				if (lowpan_fetch_skb_u8(skb, &prefix[1]))
-					goto drop;
-			}
-
-			err = lowpan_uncompress_addr(skb, &hdr.daddr, prefix,
-					lowpan_unc_mxconf[tmp], NULL);
+			err = lowpan_uncompress_multicast_daddr(
+					skb, &hdr.daddr, tmp);
 			if (err)
 				goto drop;
 		}
-- 
1.8.3.3


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[PATCH net-next 5/6] 6lowpan: lowpan_uncompress_addr with address_mode

[Alexander Aring]

This patch drop the pre and postcount calculation from the
lowpan_uncompress_addr function.

We use instead a switch case over address_mode value, it's easier
to understand what's going on there.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.c | 144 +++++++++++++++++++++++++----------------------
 net/ieee802154/6lowpan.h |   8 ++-
 2 files changed, 82 insertions(+), 70 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 0df8874..d299560 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -67,30 +67,6 @@ static const u8 lowpan_ttl_values[] = {0, 1, 64, 255};
 
 static LIST_HEAD(lowpan_devices);
 
-/*
- * Uncompression of linklocal:
- *   0 -> 16 bytes from packet
- *   1 -> 2  bytes from prefix - bunch of zeroes and 8 from packet
- *   2 -> 2  bytes from prefix - zeroes + 2 from packet
- *   3 -> 2  bytes from prefix - infer 8 bytes from lladdr
- *
- *  NOTE: => the uncompress function does change 0xf to 0x10
- *  NOTE: 0x00 => no-autoconfig => unspecified
- */
-static const u8 lowpan_unc_llconf[] = {0x0f, 0x28, 0x22, 0x20};
-
-/*
- * Uncompression of ctx-based:
- *   0 -> 0 bits  from packet [unspecified / reserved]
- *   1 -> 8 bytes from prefix - bunch of zeroes and 8 from packet
- *   2 -> 8 bytes from prefix - zeroes + 2 from packet
- *   3 -> 8 bytes from prefix - infer 8 bytes from lladdr
- */
-static const u8 lowpan_unc_ctxconf[] = {0x00, 0x88, 0x82, 0x80};
-
-/* Link local prefix */
-static const u8 lowpan_llprefix[] = {0xfe, 0x80};
-
 /* private device info */
 struct lowpan_dev_info {
 	struct net_device	*real_dev; /* real WPAN device ptr */
@@ -182,50 +158,86 @@ lowpan_compress_addr_64(u8 **hc06_ptr, u8 shift, const struct in6_addr *ipaddr,
 	return rol8(val, shift);
 }
 
-static void
-lowpan_uip_ds6_set_addr_iid(struct in6_addr *ipaddr, unsigned char *lladdr)
-{
-	memcpy(&ipaddr->s6_addr[8], lladdr, IEEE802154_ADDR_LEN);
-	/* second bit-flip (Universe/Local) is done according RFC2464 */
-	ipaddr->s6_addr[8] ^= 0x02;
-}
-
 /*
- * Uncompress addresses based on a prefix and a postfix with zeroes in
- * between. If the postfix is zero in length it will use the link address
- * to configure the IP address (autoconf style).
- * pref_post_count takes a byte where the first nibble specify prefix count
- * and the second postfix count (NOTE: 15/0xf => 16 bytes copy).
+ * Uncompress address function for source and
+ * destination address(non-multicast).
+ *
+ * address_mode is sam value or dam value.
  */
 static int
-lowpan_uncompress_addr(struct sk_buff *skb, struct in6_addr *ipaddr,
-	u8 const *prefix, u8 pref_post_count, unsigned char *lladdr)
+lowpan_uncompress_addr(struct sk_buff *skb,
+		struct in6_addr *ipaddr,
+		const u8 address_mode,
+		const struct ieee802154_addr *lladdr)
 {
-	u8 prefcount = pref_post_count >> 4;
-	u8 postcount = pref_post_count & 0x0f;
-
-	/* full nibble 15 => 16 */
-	prefcount = (prefcount == 15 ? 16 : prefcount);
-	postcount = (postcount == 15 ? 16 : postcount);
-
-	if (lladdr)
-		lowpan_raw_dump_inline(__func__, "linklocal address",
-						lladdr,	IEEE802154_ADDR_LEN);
-	if (prefcount > 0)
-		memcpy(ipaddr, prefix, prefcount);
-
-	if (postcount > 0) {
-		memcpy(&ipaddr->s6_addr[16 - postcount], skb->data, postcount);
-		skb_pull(skb, postcount);
-	} else if (prefcount > 0) {
-		if (lladdr == NULL)
+	bool fail;
+
+	switch (address_mode) {
+	case LOWPAN_IPHC_ADDR_00:
+		/* for global link addresses */
+		fail = lowpan_fetch_skb(skb, ipaddr->s6_addr, 16);
+		break;
+	case LOWPAN_IPHC_ADDR_01:
+		/* fe:80::XXXX:XXXX:XXXX:XXXX */
+		ipaddr->s6_addr[0] = 0xFE;
+		ipaddr->s6_addr[1] = 0x80;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
+		break;
+	case LOWPAN_IPHC_ADDR_02:
+		/* fe:80::ff:fe00:XXXX */
+		ipaddr->s6_addr[0] = 0xFE;
+		ipaddr->s6_addr[1] = 0x80;
+		ipaddr->s6_addr[11] = 0xFF;
+		ipaddr->s6_addr[12] = 0xFE;
+		fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
+		break;
+	case LOWPAN_IPHC_ADDR_03:
+		fail = false;
+		switch (lladdr->addr_type) {
+		case IEEE802154_ADDR_LONG:
+			/* fe:80::XXXX:XXXX:XXXX:XXXX
+			 *        \_________________/
+			 *              hwaddr
+			 */
+			ipaddr->s6_addr[0] = 0xFE;
+			ipaddr->s6_addr[1] = 0x80;
+			memcpy(&ipaddr->s6_addr[8], lladdr->hwaddr,
+					IEEE802154_ADDR_LEN);
+			/* second bit-flip (Universe/Local)
+			 * is done according RFC2464
+			 */
+			ipaddr->s6_addr[8] ^= 0x02;
+			break;
+		case IEEE802154_ADDR_SHORT:
+			/* fe:80::ff:fe00:XXXX
+			 *		  \__/
+			 *	       short_addr
+			 *
+			 * Universe/Local bit is zero.
+			 */
+			ipaddr->s6_addr[0] = 0xFE;
+			ipaddr->s6_addr[1] = 0x80;
+			ipaddr->s6_addr[11] = 0xFF;
+			ipaddr->s6_addr[12] = 0xFE;
+			memcpy(&ipaddr->s6_addr[14], &lladdr->short_addr,
+					UIP_802154_SHORTADDR_LEN);
+			break;
+		default:
+			pr_debug("Invalid addr_type set\n");
 			return -EINVAL;
+		}
+		break;
+	default:
+		pr_debug("Invalid address mode value: 0x%x\n", address_mode);
+		return -EINVAL;
+	}
 
-		/* no IID based configuration if no prefix and no data */
-		lowpan_uip_ds6_set_addr_iid(ipaddr, lladdr);
+	if (fail) {
+		pr_debug("Failed to fetch skb data\n");
+		return -EIO;
 	}
 
-	pr_debug("uncompressing %d + %d => ", prefcount, postcount);
+	pr_debug("Reconstructed ipv6 addr is:\n");
 	lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);
 
 	return 0;
@@ -775,7 +787,7 @@ lowpan_process_data(struct sk_buff *skb)
 {
 	struct ipv6hdr hdr = {};
 	u8 tmp, iphc0, iphc1, num_context = 0;
-	u8 *_saddr, *_daddr;
+	const struct ieee802154_addr *_saddr, *_daddr;
 	int err;
 
 	lowpan_raw_dump_table(__func__, "raw skb data dump", skb->data,
@@ -878,8 +890,8 @@ lowpan_process_data(struct sk_buff *skb)
 	if (lowpan_fetch_skb_u8(skb, &iphc1))
 		goto drop;
 
-	_saddr = mac_cb(skb)->sa.hwaddr;
-	_daddr = mac_cb(skb)->da.hwaddr;
+	_saddr = &mac_cb(skb)->sa;
+	_daddr = &mac_cb(skb)->da;
 
 	pr_debug("iphc0 = %02x, iphc1 = %02x\n", iphc0, iphc1);
 
@@ -961,8 +973,7 @@ lowpan_process_data(struct sk_buff *skb)
 
 	/* Source address uncompression */
 	pr_debug("source address stateless compression\n");
-	err = lowpan_uncompress_addr(skb, &hdr.saddr, lowpan_llprefix,
-				lowpan_unc_llconf[tmp], skb->data);
+	err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
 	if (err)
 		goto drop;
 
@@ -982,8 +993,7 @@ lowpan_process_data(struct sk_buff *skb)
 		}
 	} else {
 		pr_debug("dest: stateless compression\n");
-		err = lowpan_uncompress_addr(skb, &hdr.daddr, lowpan_llprefix,
-				lowpan_unc_llconf[tmp], skb->data);
+		err = lowpan_uncompress_addr(skb, &hdr.daddr, tmp, _daddr);
 		if (err)
 			goto drop;
 	}
diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index e3348ec..6596644 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -196,10 +196,12 @@
 /* Values of fields within the IPHC encoding second byte */
 #define LOWPAN_IPHC_CID		0x80
 
+#define LOWPAN_IPHC_ADDR_00	0x00
+#define LOWPAN_IPHC_ADDR_01	0x01
+#define LOWPAN_IPHC_ADDR_02	0x02
+#define LOWPAN_IPHC_ADDR_03	0x03
+
 #define LOWPAN_IPHC_SAC		0x40
-#define LOWPAN_IPHC_SAM_00	0x00
-#define LOWPAN_IPHC_SAM_01	0x10
-#define LOWPAN_IPHC_SAM_10	0x20
 #define LOWPAN_IPHC_SAM		0x30
 
 #define LOWPAN_IPHC_SAM_BIT	4
-- 
1.8.3.3


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[PATCH net-next 6/6] 6lowpan: handle context based source address

[Alexander Aring]

Handle context based address when a unspecific address is specified.
For other context based address we print a warning and drop the packet
currently because we don't support it right now.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.c | 48 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index d299560..90eddce 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -243,6 +243,39 @@ lowpan_uncompress_addr(struct sk_buff *skb,
 	return 0;
 }
 
+/* Uncompress address function for source context
+ * based address(non-multicast).
+ */
+static int
+lowpan_uncompress_context_based_src_addr(struct sk_buff *skb,
+		struct in6_addr *ipaddr,
+		const u8 sam)
+{
+	switch (sam) {
+	case LOWPAN_IPHC_ADDR_00:
+		/* unspec address ::
+		 * Do nothing, address is already ::
+		 */
+		break;
+	case LOWPAN_IPHC_ADDR_01:
+		/* TODO */
+	case LOWPAN_IPHC_ADDR_02:
+		/* TODO */
+	case LOWPAN_IPHC_ADDR_03:
+		/* TODO */
+		netdev_warn(skb->dev, "SAM value 0x%x not supported\n", sam);
+		return -EINVAL;
+	default:
+		pr_debug("Invalid sam value: 0x%x\n", sam);
+		return -EINVAL;
+	}
+
+	pr_debug("Reconstructed context based ipv6 src addr is:\n");
+	lowpan_raw_dump_inline(NULL, NULL, ipaddr->s6_addr, 16);
+
+	return 0;
+}
+
 /* Uncompress function for multicast destination address,
  * when M bit is set.
  */
@@ -971,9 +1004,18 @@ lowpan_process_data(struct sk_buff *skb)
 	/* Extract SAM to the tmp variable */
 	tmp = ((iphc1 & LOWPAN_IPHC_SAM) >> LOWPAN_IPHC_SAM_BIT) & 0x03;
 
-	/* Source address uncompression */
-	pr_debug("source address stateless compression\n");
-	err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
+	if (iphc1 & LOWPAN_IPHC_SAC) {
+		/* Source address context based uncompression */
+		pr_debug("SAC bit is set. Handle context based source address.\n");
+		err = lowpan_uncompress_context_based_src_addr(
+				skb, &hdr.saddr, tmp);
+	} else {
+		/* Source address uncompression */
+		pr_debug("source address stateless compression\n");
+		err = lowpan_uncompress_addr(skb, &hdr.saddr, tmp, _saddr);
+	}
+
+	/* Check on error of previous branch */
 	if (err)
 		goto drop;
 
-- 
1.8.3.3


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Re: [PATCHv2 net-next 0/6] 6lowpan: uncompress of addresses fix

[Alexander Smirnov]

On 08/14/2013 03:01 PM, Alexander Aring wrote:
> The current implementation to uncompress addresses in a 6lowpan header
> is completely broken.
>
> This patch series fixes the parsing of addresses in a 6lowpan header.
> It contains a major rewrite of the uncompress address function to parse
> the address in a correct way.
>

Could you please describe in a few words how have you tested the changes?

Small cosmetic hint: lowpan_raw_dump_inline() already has an argument to 
print debug message, so there is no need to add extra pr_debug calls 
before it to print static text.

Alex

> Changes since v2:
>   - Add tags for net-next
>   - Change commit msg in Patch 1/6 that this patch depends for the following
>     patches
>
> Alexander Aring (5):
>    6lowpan: init ipv6hdr buffer to zero
>    6lowpan: introduce lowpan_fetch_skb function
>    6lowpan: add function to uncompress multicast addr
>    6lowpan: lowpan_uncompress_addr with address_mode
>    6lowpan: handle context based source address
>
> David Hauweele (1):
>    6lowpan: Fix fragmentation with link-local compressed addresses
>
>   net/ieee802154/6lowpan.c | 284 +++++++++++++++++++++++++++++++----------------
>   net/ieee802154/6lowpan.h |  20 +++-
>   2 files changed, 203 insertions(+), 101 deletions(-)
>

Re: [PATCHv2 net-next 0/6] 6lowpan: uncompress of addresses fix

[Alexander Aring]

Hi Alex,

On Wed, Aug 14, 2013 at 03:23:48PM +0400, Alexander Smirnov wrote:
> On 08/14/2013 03:01 PM, Alexander Aring wrote:
> >The current implementation to uncompress addresses in a 6lowpan header
> >is completely broken.
> >
> >This patch series fixes the parsing of addresses in a 6lowpan header.
> >It contains a major rewrite of the uncompress address function to parse
> >the address in a correct way.
> >
> 
> Could you please describe in a few words how have you tested the changes?
> 

I test this with a ravenusbstick and the jackdaw firmware.
This is a usb stick with a contiki stack which offers a ipv6 interface
under linux. It still uses the 6LoWPAN contiki stack.

On the other side I have a beaglebone device with the current net-next
6LoWPAN stack.

I add several addresses to this linux device to catch all cases (except
short address) in the uncompression function.
With a ping6 $ADDRESS and wireshark on the usb stick I see the
outcomming 6lowpan packets. If I get a correct reply with the used
address it seems that the uncompression works.

I am thinking to implement some test cases to test all uncompression of
all address-cases. This patch series was tested manually.



A wireshark on the beaglebone doesn't work at the moment. I get a
nullpointer dereference in the 6LoWPAN stack. I suppose this is why the
6LoWPAN Stack copies sk_buffs and free the old one. This is a wrong
behaviour because the caller of a function has the old sk_buff which is
freed.

I need some time to drop the skb_clone functions.... and then I will
check wireshark.

If wireshark works I don't see the 6LoWPAN Header anyway, but I can see
if the ipv6 header is reconstructed correctly.

> Small cosmetic hint: lowpan_raw_dump_inline() already has an
> argument to print debug message, so there is no need to add extra
> pr_debug calls before it to print static text.
> 
ok, I will change it.

Regards
Alex

[PATCHv3 net-next 0/6] 6lowpan: address uncompression fixes

[Alexander Aring]

The current implementation to uncompress addresses in a 6lowpan header
is completely broken.

This patch series fixes the parsing of addresses in a 6lowpan header.
It contains a major rewrite of the uncompress address function to parse
the address in a correct way.

Tested with the ravenusbstick(contiki 6LoWPAN stack) and beaglebone
(linux 6LoWPAN Stack) on the other side. The linux side contains all
possible addresses for the uncompression cases. Then I type a ping6 for
each case and lookup in wireshark and dmesg the correct reconstruction.

Please apply this patch series on net-next in order 1/7 to 7/7.

Changes since v3:
 - Fix byte ordering problem in uncompression of short-address.
   Thanks for this hint.
 - drop pr_debug before lowpan_raw_dump_inline

Changes since v2:
 - Add tags for net-next
 - Change commit msg in Patch 1/6 that this patch depends for the following
   patches

Alexander Aring (5):
  6lowpan: init ipv6hdr buffer to zero
  6lowpan: introduce lowpan_fetch_skb function
  6lowpan: add function to uncompress multicast addr
  6lowpan: lowpan_uncompress_addr with address_mode
  6lowpan: handle context based source address

David Hauweele (1):
  6lowpan: Fix fragmentation with link-local compressed addresses

 net/ieee802154/6lowpan.c | 286 +++++++++++++++++++++++++++++++----------------
 net/ieee802154/6lowpan.h |  20 +++-
 2 files changed, 204 insertions(+), 102 deletions(-)

-- 
1.8.3.3


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[PATCH net-next 3/6] 6lowpan: introduce lowpan_fetch_skb function

[Alexander Aring]

This patch adds a helper function to parse the ipv6 header to a
6lowpan header in stream.

This function checks first if we can pull data with a specific
length from a skb. If this seems to be okay, we copy skb data to
a destination pointer and run skb_pull.

Signed-off-by: Alexander Aring <alex.aring-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Reviewed-by: Werner Almesberger <werner-SEdMjqphH88wryQfseakQg@public.gmane.org>
---
 net/ieee802154/6lowpan.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/ieee802154/6lowpan.h b/net/ieee802154/6lowpan.h
index 4b8f917..a636545 100644
--- a/net/ieee802154/6lowpan.h
+++ b/net/ieee802154/6lowpan.h
@@ -230,4 +230,16 @@
 					dest = 16 bit inline */
 #define LOWPAN_NHC_UDP_CS_P_11	0xF3 /* source & dest = 0xF0B + 4bit inline */
 
+static inline bool lowpan_fetch_skb(struct sk_buff *skb,
+		void *data, const unsigned int len)
+{
+	if (unlikely(!pskb_may_pull(skb, len)))
+		return true;
+
+	skb_copy_from_linear_data(skb, data, len);
+	skb_pull(skb, len);
+
+	return false;
+}
+
 #endif /* __6LOWPAN_H__ */
-- 
1.8.3.3


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