From: annie li <annie.li@oracle•com>
To: Paul Durrant <Paul.Durrant@citrix•com>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
David Vrabel <david.vrabel@citrix•com>,
Wei Liu <wei.liu2@citrix•com>,
Ian Campbell <Ian.Campbell@citrix•com>,
"xen-devel@lists•xen.org" <xen-devel@lists•xen.org>
Subject: Re: [Xen-devel] [PATCH net v2] xen-netback: fix fragment detection in checksum setup
Date: Fri, 29 Nov 2013 17:57:03 +0800 [thread overview]
Message-ID: <529864EF.6090503@oracle.com> (raw)
In-Reply-To: <9AAE0902D5BC7E449B7C8E4E778ABCD0195CB0@AMSPEX01CL01.citrite.net>
On 2013/11/29 17:10, Paul Durrant wrote:
>> -----Original Message-----
>> From: annie li [mailto:annie.li@oracle•com]
>> Sent: 29 November 2013 05:36
>> To: Paul Durrant
>> Cc: xen-devel@lists•xen.org; netdev@vger•kernel.org; Wei Liu; Ian Campbell;
>> David Vrabel
>> Subject: Re: [PATCH net v2] xen-netback: fix fragment detection in checksum
>> setup
>>
>>
>> On 2013/11/28 21:23, Paul Durrant wrote:
>>> The code to detect fragments in checksum_setup() was missing for IPv4
>> and
>>> too eager for IPv6. (It transpires that Windows seems to send IPv6 packets
>>> with a fragment header even if they are not a fragment - i.e. offset is zero,
>>> and M bit is not set).
>>>
>>> Signed-off-by: Paul Durrant <paul.durrant@citrix•com>
>>> Cc: Wei Liu <wei.liu2@citrix•com>
>>> Cc: Ian Campbell <ian.campbell@citrix•com>
>>> Cc: David Vrabel <david.vrabel@citrix•com>
>>> ---
>>> v2
>>>
>>> - Added comments noting what fragment/offset masks mean
>>>
>>> drivers/net/xen-netback/netback.c | 33
>> ++++++++++++++++++++++++++++++---
>>> 1 file changed, 30 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-
>> netback/netback.c
>>> index 919b650..c7464d8 100644
>>> --- a/drivers/net/xen-netback/netback.c
>>> +++ b/drivers/net/xen-netback/netback.c
>>> @@ -1165,15 +1165,28 @@ static int checksum_setup_ip(struct xenvif *vif,
>> struct sk_buff *skb,
>>> struct iphdr *iph = (void *)skb->data;
>>> unsigned int header_size;
>>> unsigned int off;
>>> + bool fragment;
>>> int err = -EPROTO;
>>>
>>> + fragment = false;
>> Is it better to initialize fragment directly as following?
>> bool fragment = false;
>>
> I think that's a matter of personal taste. I tend to favour this style.
>
That is OK, I point this out because it is inconsistent with other
variable initialization in netback.c.
Thanks
Annie
>
>>> +
>>> off = sizeof(struct iphdr);
>>>
>>> header_size = skb->network_header + off + MAX_IPOPTLEN;
>>> maybe_pull_tail(skb, header_size);
>>>
>>> + /* 3fff -> fragment offset != 0 OR more fragments */
>>> + if (ntohs(iph->frag_off) & 0x3fff)
>>> + fragment = true;
>>> +
>>> off = iph->ihl * 4;
>>>
>>> + if (fragment) {
>>> + if (net_ratelimit())
>>> + netdev_err(vif->dev, "Packet is a fragment!\n");
>>> + goto out;
>>> + }
>>> +
>>> switch (iph->protocol) {
>>> case IPPROTO_TCP:
>>> if (!skb_partial_csum_set(skb, off,
>>> @@ -1237,6 +1250,7 @@ static int checksum_setup_ipv6(struct xenvif *vif,
>> struct sk_buff *skb,
>>> bool fragment;
>>> bool done;
>>>
>>> + fragment = false;
>>> done = false;
>> Same as above for "done" and "fragment"...
>>
>> Thanks
>> Annie
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists•xen.org
> http://lists.xen.org/xen-devel
prev parent reply other threads:[~2013-11-29 9:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-28 13:23 [PATCH net v2] xen-netback: fix fragment detection in checksum setup Paul Durrant
2013-11-28 17:29 ` Eric Dumazet
2013-11-29 10:32 ` Paul Durrant
2013-11-29 5:35 ` annie li
2013-11-29 9:10 ` Paul Durrant
2013-11-29 9:57 ` annie li [this message]
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