Commit 1188f054 authored by Jukka Rissanen's avatar Jukka Rissanen Committed by David S. Miller

6lowpan: Uncompression of traffic class field was incorrect

If priority/traffic class field in IPv6 header is set (seen when
using ssh), the uncompression sets the TC and Flow fields incorrectly.

Example:

This is IPv6 header of a sent packet. Note the priority/TC (=1) in
the first byte.

00000000: 61 00 00 00 00 2c 06 40 fe 80 00 00 00 00 00 00
00000010: 02 02 72 ff fe c6 42 10 fe 80 00 00 00 00 00 00
00000020: 02 1e ab ff fe 4c 52 57

This gets compressed like this in the sending side

00000000: 72 31 04 06 02 1e ab ff fe 4c 52 57 ec c2 00 16
00000010: aa 2d fe 92 86 4e be c6 ....

In the receiving end, the packet gets uncompressed to this
IPv6 header

00000000: 60 06 06 02 00 2a 1e 40 fe 80 00 00 00 00 00 00
00000010: 02 02 72 ff fe c6 42 10 fe 80 00 00 00 00 00 00
00000020: ab ff fe 4c 52 57 ec c2

First four bytes are set incorrectly and we have also lost
two bytes from destination address.

The fix is to switch the case values in switch statement
when checking the TC field.
Signed-off-by: default avatarJukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3db0a197
...@@ -956,7 +956,7 @@ lowpan_process_data(struct sk_buff *skb) ...@@ -956,7 +956,7 @@ lowpan_process_data(struct sk_buff *skb)
* Traffic class carried in-line * Traffic class carried in-line
* ECN + DSCP (1 byte), Flow Label is elided * ECN + DSCP (1 byte), Flow Label is elided
*/ */
case 1: /* 10b */ case 2: /* 10b */
if (lowpan_fetch_skb_u8(skb, &tmp)) if (lowpan_fetch_skb_u8(skb, &tmp))
goto drop; goto drop;
...@@ -967,7 +967,7 @@ lowpan_process_data(struct sk_buff *skb) ...@@ -967,7 +967,7 @@ lowpan_process_data(struct sk_buff *skb)
* Flow Label carried in-line * Flow Label carried in-line
* ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided * ECN + 2-bit Pad + Flow Label (3 bytes), DSCP is elided
*/ */
case 2: /* 01b */ case 1: /* 01b */
if (lowpan_fetch_skb_u8(skb, &tmp)) if (lowpan_fetch_skb_u8(skb, &tmp))
goto drop; goto drop;
......
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