From: Vlad Yasevich <vyasevich@gmail•com>
To: Fan Du <fan.du@windriver•com>
Cc: nhorman@tuxdriver•com, nicolas.dichtel@6wind•com,
davem@davemloft•net, netdev@vger•kernel.org
Subject: Re: [RFC PATCH] sctp: Don't lookup dst if transport dst is still valid
Date: Wed, 03 Jul 2013 09:23:03 -0400 [thread overview]
Message-ID: <51D425B7.20204@gmail.com> (raw)
In-Reply-To: <51D389F9.4030804@windriver.com>
On 07/02/2013 10:18 PM, Fan Du wrote:
>
>
> On 2013年07月02日 22:29, Vlad Yasevich wrote:
>> On 07/02/2013 02:39 AM, Fan Du wrote:
>>> When sctp sits on IPv6, sctp_transport_dst_check pass cookie as ZERO,
>>> as a result ip6_dst_check always fail out. This behaviour makes
>>> transport->dst useless, because every sctp_packet_transmit must look
>>> for valid dst(Is this what supposed to be?)
>>>
>>> One aggressive way is to call rt_genid_bump which invalid all dst to
>>> make new dst for transport, apparently it also hurts others.
>>> I'm sure this may not be the best for all, so any commnets?
>>>
>>> Signed-off-by: Fan Du <fan.du@windriver•com>
>>> ---
>>> include/net/sctp/sctp.h | 18 ++++++++++++------
>>> net/sctp/ipv6.c | 2 ++
>>> 2 files changed, 14 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
>>> index cd89510..f05af01 100644
>>> --- a/include/net/sctp/sctp.h
>>> +++ b/include/net/sctp/sctp.h
>>> @@ -719,14 +719,20 @@ static inline void sctp_v4_map_v6(union
>>> sctp_addr *addr)
>>> addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
>>> }
>>>
>>> -/* The cookie is always 0 since this is how it's used in the
>>> - * pmtu code.
>>> - */
>>> +/* Set cookie with the right one for IPv6 and zero for others */
>>> static inline struct dst_entry *sctp_transport_dst_check(struct
>>> sctp_transport *t)
>>> {
>>> - if (t->dst && !dst_check(t->dst, 0)) {
>>> - dst_release(t->dst);
>>> - t->dst = NULL;
>>> +
>>> + if (t->dst) {
>>> + struct rt6_info *rt = (struct rt6_info *)t->dst;
>>> + u32 cookie = 0;
>>> +
>>> + if ((t->af_specific->sa_family == AF_INET6) && rt->rt6i_node)
>>> + cookie = rt->rt6i_node->fn_sernum;
>>> + if (!dst_check(t->dst, cookie)) {
>>> + dst_release(t->dst);
>>> + t->dst = NULL;
>>> + }
>>> }
>>
>> I think it would be better if we stored the dst_cookie in the
>> transport structure and initialized it at lookup time. If you do that,
>> then if the route table changes, we'd correctly detect it without
>> artificially bumping rt_genid (and hurting ipv4).
>
> Hi Vlad/Neil
>
> Is this what you mean?
Yes, exactly.
-vlad
>
> diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h
> index cd89510..0a646a5 100644
> --- a/include/net/sctp/sctp.h
> +++ b/include/net/sctp/sctp.h
> @@ -724,7 +724,7 @@ static inline void sctp_v4_map_v6(union sctp_addr
> *addr)
> */
> static inline struct dst_entry *sctp_transport_dst_check(struct
> sctp_transport *t)
> {
> - if (t->dst && !dst_check(t->dst, 0)) {
> + if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
> dst_release(t->dst);
> t->dst = NULL;
> }
> diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
> index 1bd4c41..cafdd19 100644
> --- a/include/net/sctp/structs.h
> +++ b/include/net/sctp/structs.h
> @@ -946,6 +946,8 @@ struct sctp_transport {
> __u64 hb_nonce;
>
> struct rcu_head rcu;
> +
> + u32 dst_cookie;
> };
>
> struct sctp_transport *sctp_transport_new(struct net *, const union
> sctp_addr *,
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index 8ee553b..82a420f 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -350,6 +350,7 @@ out:
> struct rt6_info *rt;
> rt = (struct rt6_info *)dst;
> t->dst = dst;
> + t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum
> : 0;
> SCTP_DEBUG_PRINTK("rt6_dst:%pI6 rt6_src:%pI6\n",
> &rt->rt6i_dst.addr, &fl6->saddr);
> } else {
>
>
>
>
>
>> -vlad
>>
>>>
>>> return t->dst;
>>> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
>>> index 8ee553b..cfae77e 100644
>>> --- a/net/sctp/ipv6.c
>>> +++ b/net/sctp/ipv6.c
>>> @@ -137,6 +137,8 @@ static int sctp_inet6addr_event(struct
>>> notifier_block *this, unsigned long ev,
>>> break;
>>> }
>>>
>>> + /* invalid all transport dst forcing to look up new dst */
>>> + rt_genid_bump(net);
>>> return NOTIFY_DONE;
>>> }
>>>
>>>
>>
>>
>
next prev parent reply other threads:[~2013-07-03 13:23 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-02 6:39 [RFC PATCH] sctp: Don't lookup dst if transport dst is still valid Fan Du
2013-07-02 14:29 ` Vlad Yasevich
2013-07-02 15:55 ` Neil Horman
2013-07-03 2:39 ` Fan Du
2013-07-03 13:48 ` Vlad Yasevich
2013-07-02 19:47 ` David Miller
2013-07-03 2:18 ` Fan Du
2013-07-03 13:23 ` Vlad Yasevich [this message]
2013-07-03 14:11 ` Vlad Yasevich
2013-07-04 2:33 ` Fan Du
2013-07-05 13:03 ` Neil Horman
2013-07-09 7:11 ` Fan Du
2013-07-09 11:38 ` Neil Horman
2013-07-05 14:09 ` Vlad Yasevich
2013-07-09 15:11 ` Vlad Yasevich
2013-07-10 5:26 ` Fan Du
2013-07-12 11:19 ` Neil Horman
2013-07-16 9:13 ` Fan Du
2013-07-13 12:21 ` Vlad Yasevich
2013-07-17 7:04 ` Fan Du
2013-07-12 3:15 ` Fan Du
2013-07-12 22:58 ` David Miller
2013-07-13 12:18 ` Vlad Yasevich
2013-07-16 9:58 ` Fan Du
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=51D425B7.20204@gmail.com \
--to=vyasevich@gmail$(echo .)com \
--cc=davem@davemloft$(echo .)net \
--cc=fan.du@windriver$(echo .)com \
--cc=netdev@vger$(echo .)kernel.org \
--cc=nhorman@tuxdriver$(echo .)com \
--cc=nicolas.dichtel@6wind$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox