[PATCH] [NET] Fix ECN Encapsulation

[YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@xxxxxxxxxxxxxx>]

Hello.

Please pull the following changeset from
   <bk://bk.skbuff.net:20609/linux-2.6-tunnel/>.

Thank you.

HEADLINE
--------
ChangeSet@xxxxxx, 2004-10-06 11:28:16+09:00, yoshfuji@xxxxxxxxxxxxxx
 [NET] ECN: Fix bug in tunnel ECN handling by recent changes.


DIFFSTAT
--------
 include/net/inet_ecn.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletion(-)


CHANGESET
---------
ChangeSet@xxxxxx, 2004-10-06 11:28:16+09:00, yoshfuji@xxxxxxxxxxxxxx
 [NET] ECN: Fix bug in tunnel ECN handling by recent changes.
 
 We broke ECN encapsulation in tunnels recently.
 Without this patch, even though encapusulated (inner) packet is 
 "not-ECN", encapusulating (outer) packet is sent with "ECT(0)" set.
 This is wrong and should be "not-ECN."
 This patch fixes up.
 
 From RFC3168:
    The full-functionality option for ECN encapsulation is to copy the
    ECN codepoint of the inside header to the outside header on
    encapsulation if the inside header is not-ECT or ECT, and to set the
    ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
    the inside header is CE.
 
 Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>

diff -Nru a/include/net/inet_ecn.h b/include/net/inet_ecn.h
--- a/include/net/inet_ecn.h    2004-10-06 11:30:10 +09:00
+++ b/include/net/inet_ecn.h    2004-10-06 11:30:10 +09:00
@@ -30,7 +30,8 @@
 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
 {
        outer &= ~INET_ECN_MASK;
-       outer |= (inner & INET_ECN_MASK) ?: INET_ECN_ECT_0;
+       outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
+                                         INET_ECN_ECT_0;
        return outer;
 }
 

-- 
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@xxxxxxxxxxxxxx>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF  80D8 4807 F894 E062 0EEA