From: Tom Herbert <therbert@google.com>
To: Wei Yongjun <yjwei@cn.fujitsu.com>
Cc: David Miller <davem@davemloft.net>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next] net: fix skb_add_data_nocache() to calc csum correctly
Date: Wed, 6 Apr 2011 21:50:55 -0700 [thread overview]
Message-ID: <BANLkTikspQHnjagFme0S3GdPUo-zw48zBw@mail.gmail.com> (raw)
In-Reply-To: <4D9D402C.60107@cn.fujitsu.com>
Nice catch.
Acked-by: Tom Herbert <therbert@google.com>
On Wed, Apr 6, 2011 at 9:40 PM, Wei Yongjun <yjwei@cn.fujitsu.com> wrote:
> commit c6e1a0d12ca7b4f22c58e55a16beacfb7d3d8462 broken the calc
> (net: Allow no-cache copy from user on transmit)
> of checksum, which may cause some tcp packets be dropped because
> incorrect checksum. ssh does not work under today's net-next-2.6
> tree.
>
> Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
> ---
> include/net/sock.h | 15 ++++++++-------
> 1 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 43bd515..9cbf23c 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -1392,14 +1392,14 @@ static inline void sk_nocaps_add(struct sock *sk, int flags)
>
> static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
> char __user *from, char *to,
> - int copy)
> + int copy, int offset)
> {
> if (skb->ip_summed == CHECKSUM_NONE) {
> int err = 0;
> __wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
> if (err)
> return err;
> - skb->csum = csum_block_add(skb->csum, csum, skb->len);
> + skb->csum = csum_block_add(skb->csum, csum, offset);
> } else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
> if (!access_ok(VERIFY_READ, from, copy) ||
> __copy_from_user_nocache(to, from, copy))
> @@ -1413,11 +1413,12 @@ static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
> static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
> char __user *from, int copy)
> {
> - int err;
> + int err, offset = skb->len;
>
> - err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy), copy);
> + err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
> + copy, offset);
> if (err)
> - __skb_trim(skb, skb->len);
> + __skb_trim(skb, offset);
>
> return err;
> }
> @@ -1429,8 +1430,8 @@ static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
> {
> int err;
>
> - err = skb_do_copy_data_nocache(sk, skb, from,
> - page_address(page) + off, copy);
> + err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
> + copy, skb->len);
> if (err)
> return err;
>
> --
> 1.6.5.2
>
>
>
next prev parent reply other threads:[~2011-04-07 4:51 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-07 4:40 [PATCH net-next] net: fix skb_add_data_nocache() to calc csum correctly Wei Yongjun
2011-04-07 4:50 ` Tom Herbert [this message]
2011-04-07 6:05 ` David Miller
-- strict thread matches above, loose matches on Subject: below --
2011-04-07 12:05 Sedat Dilek
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