Re: [PATCH v5 5/6] 6lowpan: Use netdev addr_len to determine lladdr len

[Alexander Aring]

H

On 02/27/2017 08:13 AM, Alexander Aring wrote:
> Hi,
> 
> On 02/24/2017 01:14 PM, Luiz Augusto von Dentz wrote:
>> From: Luiz Augusto von Dentz 
>>
>> This allow technologies such as Bluetooth to use its native lladdr which
>> is eui48 instead of eui64 which was expected by functions like
>> lowpan_header_decompress and lowpan_header_compress.
>>
>> Signed-off-by: Luiz Augusto von Dentz 
>> Reviewed-by: Stefan Schmidt 
>> ---
>>  include/net/6lowpan.h   | 19 +++
>>  net/6lowpan/iphc.c  | 49 
>> ++---
>>  net/bluetooth/6lowpan.c | 42 ++
>>  3 files changed, 63 insertions(+), 47 deletions(-)
>>
>> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
>> index 5ab4c99..c5792cb 100644
>> --- a/include/net/6lowpan.h
>> +++ b/include/net/6lowpan.h
>> @@ -198,6 +198,25 @@ static inline void 
>> lowpan_iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
>>  ipaddr->s6_addr[8] ^= 0x02;
>>  }
>>  
>> +static inline void lowpan_iphc_uncompress_eui48_lladdr(struct in6_addr 
>> *ipaddr,
>> +   const void *lladdr)
>> +{
>> +/* fe:80:::XXff:feXX:
>> + *\_/
>> + *  hwaddr
>> + */
>> +ipaddr->s6_addr[0] = 0xFE;
>> +ipaddr->s6_addr[1] = 0x80;
>> +memcpy(>s6_addr[8], lladdr, 3);
>> +ipaddr->s6_addr[11] = 0xFF;
>> +ipaddr->s6_addr[12] = 0xFE;
>> +memcpy(>s6_addr[13], lladdr + 3, 3);
>> +/* second bit-flip (Universe/Local)
>> + * is done according RFC2464
>> + */
>> +ipaddr->s6_addr[8] ^= 0x02;
>> +}
>> +
> 
> same thing here. I think you don't need u/l bitflip here, you argumented
> already that IID is without it in another patch, or?
> 

ahhh, got it. You just moved the function into the header and patch 6/6
will remove the u/l handling. Sorry!

But then still patch 4/6 is wrong because it use u/l bitflip there.
(It's my patch yes :D, but I realized at first dev->addr_len should be 6
and not 8).

- Alex

Re: [PATCH v5 5/6] 6lowpan: Use netdev addr_len to determine lladdr len

[Alexander Aring]

Hi,

On 02/24/2017 01:14 PM, Luiz Augusto von Dentz wrote:
> From: Luiz Augusto von Dentz 
> 
> This allow technologies such as Bluetooth to use its native lladdr which
> is eui48 instead of eui64 which was expected by functions like
> lowpan_header_decompress and lowpan_header_compress.
> 
> Signed-off-by: Luiz Augusto von Dentz 
> Reviewed-by: Stefan Schmidt 
> ---
>  include/net/6lowpan.h   | 19 +++
>  net/6lowpan/iphc.c  | 49 
> ++---
>  net/bluetooth/6lowpan.c | 42 ++
>  3 files changed, 63 insertions(+), 47 deletions(-)
> 
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index 5ab4c99..c5792cb 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -198,6 +198,25 @@ static inline void 
> lowpan_iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
>   ipaddr->s6_addr[8] ^= 0x02;
>  }
>  
> +static inline void lowpan_iphc_uncompress_eui48_lladdr(struct in6_addr 
> *ipaddr,
> +const void *lladdr)
> +{
> + /* fe:80:::XXff:feXX:
> +  *\_/
> +  *  hwaddr
> +  */
> + ipaddr->s6_addr[0] = 0xFE;
> + ipaddr->s6_addr[1] = 0x80;
> + memcpy(>s6_addr[8], lladdr, 3);
> + ipaddr->s6_addr[11] = 0xFF;
> + ipaddr->s6_addr[12] = 0xFE;
> + memcpy(>s6_addr[13], lladdr + 3, 3);
> + /* second bit-flip (Universe/Local)
> +  * is done according RFC2464
> +  */
> + ipaddr->s6_addr[8] ^= 0x02;
> +}
> +

same thing here. I think you don't need u/l bitflip here, you argumented
already that IID is without it in another patch, or?

btw: making static inline function -> then remove link-local setting
here before. Then we can use this function for ipv6/sateful/stateless
IPHC compression/decompression to generate IID.
And better with a function before that evaluates lltype (or dev->addr_len,
see below why not).

another thing is:
__ipv6_addr_set_half(_addr32[0], htonl(0xFE80), 0);

should be used here, but this need to be cleanuped everywhere in 6lowpan
code. :-)

---

What I mean such function placed in 6lowpan header should only set the
IID according a ipaddr.
Such function can also be used then in IPv6 IID generation.

And DON'T make such handling depending on address size, this is in my
opinion wrong. Because the link-layer 6lowpan adaption RFC describes how
to generate the IID and not depending on a address size.
Means another link-layer e.g. has eui48 but will set a u/l bitflip here.
You should use the lltype of 6lowpan netdev private area for that.

This means also the name "eui48" in the function is also semantic wrong,
at my point of view.
(Okay, I don't care about function names right now).

Anyway, I agree that doesn't matter currently because we have only two
adaptions right now.
... and yes, I know (already more about ~one year) BTLE 6LoWPAN is
broken (races/rfc stuff) and I am happy that somebody fix that now.
So I would also ack patches which makes it depending on dev->addr_len.
Otherwise broken things will never be fixed...

- Alex

[PATCH v5 5/6] 6lowpan: Use netdev addr_len to determine lladdr len

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz 

This allow technologies such as Bluetooth to use its native lladdr which
is eui48 instead of eui64 which was expected by functions like
lowpan_header_decompress and lowpan_header_compress.

Signed-off-by: Luiz Augusto von Dentz 
Reviewed-by: Stefan Schmidt 
---
 include/net/6lowpan.h   | 19 +++
 net/6lowpan/iphc.c  | 49 ++---
 net/bluetooth/6lowpan.c | 42 ++
 3 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index 5ab4c99..c5792cb 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -198,6 +198,25 @@ static inline void 
lowpan_iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
ipaddr->s6_addr[8] ^= 0x02;
 }
 
+static inline void lowpan_iphc_uncompress_eui48_lladdr(struct in6_addr *ipaddr,
+  const void *lladdr)
+{
+   /* fe:80:::XXff:feXX:
+*\_/
+*  hwaddr
+*/
+   ipaddr->s6_addr[0] = 0xFE;
+   ipaddr->s6_addr[1] = 0x80;
+   memcpy(>s6_addr[8], lladdr, 3);
+   ipaddr->s6_addr[11] = 0xFF;
+   ipaddr->s6_addr[12] = 0xFE;
+   memcpy(>s6_addr[13], lladdr + 3, 3);
+   /* second bit-flip (Universe/Local)
+* is done according RFC2464
+*/
+   ipaddr->s6_addr[8] ^= 0x02;
+}
+
 #ifdef DEBUG
 /* print data in line */
 static inline void raw_dump_inline(const char *caller, char *msg,
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index fb5f6fa..6b1042e 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -278,6 +278,23 @@ lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device 
*dev,
return ret;
 }
 
+static void lowpan_iphc_uncompress_lladdr(const struct net_device *dev,
+ struct in6_addr *ipaddr,
+ const void *lladdr)
+{
+   switch (dev->addr_len) {
+   case ETH_ALEN:
+   lowpan_iphc_uncompress_eui48_lladdr(ipaddr, lladdr);
+   break;
+   case EUI64_ADDR_LEN:
+   lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
+   break;
+   default:
+   WARN_ON_ONCE(1);
+   break;
+   }
+}
+
 /* Uncompress address function for source and
  * destination address(non-multicast).
  *
@@ -320,7 +337,7 @@ static int lowpan_iphc_uncompress_addr(struct sk_buff *skb,
lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
break;
default:
-   lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
+   lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
break;
}
break;
@@ -381,7 +398,7 @@ static int lowpan_iphc_uncompress_ctx_addr(struct sk_buff 
*skb,
lowpan_iphc_uncompress_802154_lladdr(ipaddr, lladdr);
break;
default:
-   lowpan_iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
+   lowpan_iphc_uncompress_lladdr(dev, ipaddr, lladdr);
break;
}
ipv6_addr_prefix_copy(ipaddr, >pfx, ctx->plen);
@@ -810,6 +827,21 @@ lowpan_iphc_compress_ctx_802154_lladdr(const struct 
in6_addr *ipaddr,
return lladdr_compress;
 }
 
+static bool lowpan_iphc_addr_equal(const struct net_device *dev,
+  const struct lowpan_iphc_ctx *ctx,
+  const struct in6_addr *ipaddr,
+  const void *lladdr)
+{
+   struct in6_addr tmp = {};
+
+   lowpan_iphc_uncompress_lladdr(dev, , lladdr);
+
+   if (ctx)
+   ipv6_addr_prefix_copy(, >pfx, ctx->plen);
+
+   return ipv6_addr_equal(, ipaddr);
+}
+
 static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
   const struct in6_addr *ipaddr,
   const struct lowpan_iphc_ctx *ctx,
@@ -827,13 +859,7 @@ static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const 
struct net_device *dev,
}
break;
default:
-   /* check for SAM/DAM = 11 */
-   memcpy(_addr[8], lladdr, EUI64_ADDR_LEN);
-   /* second bit-flip (Universe/Local) is done according RFC2464 */
-   tmp.s6_addr[8] ^= 0x02;
-   /* context information are always used */
-   ipv6_addr_prefix_copy(, >pfx, ctx->plen);
-   if (ipv6_addr_equal(, ipaddr)) {
+   if (lowpan_iphc_addr_equal(dev, ctx, ipaddr, lladdr)) {
dam = LOWPAN_IPHC_DAM_11;
goto