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: Tue, 02 Jul 2013 10:29:28 -0400 [thread overview]
Message-ID: <51D2E3C8.5050100@gmail.com> (raw)
In-Reply-To: <1372747174-23580-1-git-send-email-fan.du@windriver.com>
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).
-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:[~2013-07-02 14:29 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 [this message]
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
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
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