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

Hi,

On 02/15/2017 11:16 AM, Luiz Augusto von Dentz wrote:

Hi Alex,

On Wed, Feb 15, 2017 at 10:24 AM, Luiz Augusto von Dentz
[off-list ref] wrote:

quoted

Hi Alex,

On Wed, Feb 15, 2017 at 9:44 AM, Alexander Aring [off-list ref] wrote:

quoted

Hi,

On 02/09/2017 03:55 PM, Luiz Augusto von Dentz wrote:

quoted

From: Luiz Augusto von Dentz <redacted>

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 <redacted>
---
 net/6lowpan/iphc.c      | 17 +++++++++++++++--
 net/bluetooth/6lowpan.c | 43 ++++++++++---------------------------------
 2 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index fb5f6fa..ee88feb 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c

@@ -827,8 +827,21 @@ static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct net_device *dev,
              }
              break;
      default:
-             /* check for SAM/DAM = 11 */
-             memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
+             switch (dev->addr_len) {
+             case ETH_ALEN:
+                     memcpy(&tmp.s6_addr[8], lladdr, 3);
+                     tmp.s6_addr[11] = 0xFF;
+                     tmp.s6_addr[12] = 0xFE;
+                     memcpy(&tmp.s6_addr[13], lladdr + 3, 3);
+                     break;
+             case EUI64_ADDR_LEN:
+                     memcpy(&tmp.s6_addr[8], lladdr, EUI64_ADDR_LEN);
+                     break;
+             default:
+                     dam = LOWPAN_IPHC_DAM_11;
+                     goto out;
+             }
+
              /* second bit-flip (Universe/Local) is done according RFC2464 */
              tmp.s6_addr[8] ^= 0x02;

move this handling in per link-layer layer decision, see below.

quoted

              /* context information are always used */

PLEASE... and this is one of my rant!

PLEASE LOOK WHAT I HAVE DONE IN THIS FILE IN MY RFC PATCH SERIES YOU
NEED TO FIX MORE THAN JUST CONTEXT BASED COMPRESSION.

e.g. stateless un/compression

I haven't changed that and probably it needs a separate patch in that
case since Im only, and I really mean only, fixing the address length
and because your patches end up changing a lot more things it is
pretty hard to extract the exact parts that fixes this.

Btw I just checked your patch and there doesn't seem to have fix what
you saying, in fact it is exact the same code as above:

http://www.spinics.net/lists/linux-bluetooth/msg67937.html

Just to be sure we talking about the both thing:

For example:
  lowpan_iphc_uncompress_addr


You didn't changed that function which still use 8 byte lladdr and FF:FE
pattern. It will still be broken.

My idea: Make a callback with prefix and lladdr as parameter to generate
such address. Then on stateless you can call it with L2 saddr/daddr and
ff80::/64 prefix. For stateful the same but with prefix from context
table.

btw: I cc now linux-wpan.

- Alex