From: Vlad Yasevich <vyasevich@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>, Wolfgang Walter <linux@stwm.de>
Cc: netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net] Revert "ipv6: Allow for partial checksums on non-ufo packets"
Date: Tue, 12 May 2015 14:05:40 -0400 [thread overview]
Message-ID: <555240F4.4070406@gmail.com> (raw)
In-Reply-To: <1431123765.22756.51.camel@edumazet-glaptop2.roam.corp.google.com>
On 05/08/2015 06:22 PM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Wolfgang Walter reported crashes using traceroute6, root caused to this
> commit.
>
> UDP packets can be sent from RAW sockets.
>
> Note that the faulty commit addressed a non problem, as normal
> UDP v6 packets use udp_v6_send_skb() which correctly setup
> CHECKSUM_PARTIAL properly if device has the correct feature.
Actually, they didn't. udp_v6_send_skb() uses ip_summed from
the skb, which is populated by __ip6_append_data. That in turn
always set it CHECKSUM_NONE.
The code in question looks identically to that of __ip_append_data().
The problem is similar in both places.
-vlad
>
> It seems not worth trying to 'fix' the raw path.
>
> Fixes: 32dce968dd98 ("ipv6: Allow for partial checksums on non-ufo packets")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Wolfgang Walter <linux@stwm.de>
> Cc: Vlad Yasevich <vyasevich@gmail.com>
> ---
> net/ipv6/ip6_output.c | 11 +----------
> 1 file changed, 1 insertion(+), 10 deletions(-)
>
> diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
> index 7fde1f265c90..1fe5c687328e 100644
> --- a/net/ipv6/ip6_output.c
> +++ b/net/ipv6/ip6_output.c
> @@ -1218,7 +1218,6 @@ static int __ip6_append_data(struct sock *sk,
> u32 tskey = 0;
> struct rt6_info *rt = (struct rt6_info *)cork->dst;
> struct ipv6_txoptions *opt = v6_cork->opt;
> - int csummode = CHECKSUM_NONE;
>
> skb = skb_peek_tail(queue);
> if (!skb) {
> @@ -1275,14 +1274,6 @@ emsgsize:
> tskey = sk->sk_tskey++;
> }
>
> - /* If this is the first and only packet and device
> - * supports checksum offloading, let's use it.
> - */
> - if (!skb && sk->sk_protocol == IPPROTO_UDP &&
> - length + fragheaderlen < mtu &&
> - rt->dst.dev->features & NETIF_F_V6_CSUM &&
> - !exthdrlen)
> - csummode = CHECKSUM_PARTIAL;
> /*
> * Let's try using as much space as possible.
> * Use MTU if total length of the message fits into the MTU.
> @@ -1396,7 +1387,7 @@ alloc_new_skb:
> * Fill in the control structures
> */
> skb->protocol = htons(ETH_P_IPV6);
> - skb->ip_summed = csummode;
> + skb->ip_summed = CHECKSUM_NONE;
> skb->csum = 0;
> /* reserve for fragmentation and ipsec header */
> skb_reserve(skb, hh_len + sizeof(struct frag_hdr) +
>
>
next prev parent reply other threads:[~2015-05-12 18:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1770409.aMESoOv08f@h2o.as.studentenwerk.mhn.de>
[not found] ` <1958390.Ugr57PpLDS@h2o.as.studentenwerk.mhn.de>
2015-05-06 18:15 ` kernel >= 4.0: crashes when using traceroute6 with isatap Cong Wang
2015-05-06 19:10 ` Eric Dumazet
2015-05-06 22:04 ` Wolfgang Walter
2015-05-06 22:42 ` Eric Dumazet
2015-05-07 0:04 ` Wolfgang Walter
2015-05-12 16:34 ` Vlad Yasevich
2015-05-06 22:11 ` Wolfgang Walter
2015-05-12 20:18 ` Vlad Yasevich
2015-05-12 20:36 ` Eric Dumazet
2015-05-12 20:46 ` Vlad Yasevich
2015-05-14 0:32 ` Wolfgang Walter
[not found] ` <1431002384.22756.0.camel@edumazet-glaptop2.roam.corp.google.com>
[not found] ` <12346713.ZyFExCo3ux@h2o.as.studentenwerk.mhn.de>
[not found] ` <2088438.42IY8hjjd5@h2o.as.studentenwerk.mhn.de>
[not found] ` <1431122268.22756.41.camel@edumazet-glaptop2.roam.corp.google.com>
2015-05-08 22:22 ` [PATCH net] Revert "ipv6: Allow for partial checksums on non-ufo packets" Eric Dumazet
2015-05-10 23:53 ` David Miller
2015-05-12 18:05 ` Vlad Yasevich [this message]
2015-05-12 19:07 ` Eric Dumazet
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