netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 3.13.y-ckt 67/80] lib/checksum.c: fix carry in csum_tcpudp_nofold
       [not found] <1426804568-2907-1-git-send-email-kamal@canonical.com>
@ 2015-03-19 22:35 ` Kamal Mostafa
  0 siblings, 0 replies; only message in thread
From: Kamal Mostafa @ 2015-03-19 22:35 UTC (permalink / raw)
  To: linux-kernel, stable, kernel-team
  Cc: Karl Beldan, Al Viro, Eric Dumazet, Arnd Bergmann, Mike Frysinger,
	netdev, Eric Dumazet, David S. Miller, Kamal Mostafa

3.13.11-ckt17 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: karl beldan <karl.beldan@gmail.com>

commit 150ae0e94634714b23919f0c333fee28a5b199d5 upstream.

The carry from the 64->32bits folding was dropped, e.g with:
saddr=0xFFFFFFFF daddr=0xFF0000FF len=0xFFFF proto=0 sum=1,
csum_tcpudp_nofold returned 0 instead of 1.

Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 lib/checksum.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/checksum.c b/lib/checksum.c
index 129775e..fcf3894 100644
--- a/lib/checksum.c
+++ b/lib/checksum.c
@@ -47,6 +47,15 @@ static inline unsigned short from32to16(unsigned int x)
 	return x;
 }
 
+static inline u32 from64to32(u64 x)
+{
+	/* add up 32-bit and 32-bit for 32+c bit */
+	x = (x & 0xffffffff) + (x >> 32);
+	/* add up carry.. */
+	x = (x & 0xffffffff) + (x >> 32);
+	return (u32)x;
+}
+
 static unsigned int do_csum(const unsigned char *buff, int len)
 {
 	int odd;
@@ -195,8 +204,7 @@ __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
 #else
 	s += (proto + len) << 8;
 #endif
-	s += (s >> 32);
-	return (__force __wsum)s;
+	return (__force __wsum)from64to32(s);
 }
 EXPORT_SYMBOL(csum_tcpudp_nofold);
 #endif
-- 
1.9.1

^ permalink raw reply related	[flat|nested] only message in thread

only message in thread, other threads:[~2015-03-19 22:35 UTC | newest]

Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
     [not found] <1426804568-2907-1-git-send-email-kamal@canonical.com>
2015-03-19 22:35 ` [PATCH 3.13.y-ckt 67/80] lib/checksum.c: fix carry in csum_tcpudp_nofold Kamal Mostafa

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).