diff options
| author | karl beldan <karl.beldan@gmail.com> | 2015-01-28 10:58:11 +0100 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-04-14 17:33:59 +0800 |
| commit | bd3ccdba19b80e736b7844b6800fa9836fbca5af (patch) | |
| tree | 7e6bc3f5f8c579f099c204ee34d6c8ab4516dac5 | |
| parent | 574b59db6504ed3867c2f566f167f764e97ee402 (diff) | |
lib/checksum.c: fix carry in csum_tcpudp_nofold
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: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | lib/checksum.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/lib/checksum.c b/lib/checksum.c index 12dceb27ff20..edbf473595d3 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; @@ -193,8 +202,7 @@ __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 |