From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [RFC PATCH] sctp: Don't lookup dst if transport dst is still valid Date: Tue, 02 Jul 2013 10:29:28 -0400 Message-ID: <51D2E3C8.5050100@gmail.com> References: <1372747174-23580-1-git-send-email-fan.du@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: nhorman@tuxdriver.com, nicolas.dichtel@6wind.com, davem@davemloft.net, netdev@vger.kernel.org To: Fan Du Return-path: Received: from mail-yh0-f44.google.com ([209.85.213.44]:59913 "EHLO mail-yh0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751503Ab3GBO3b (ORCPT ); Tue, 2 Jul 2013 10:29:31 -0400 Received: by mail-yh0-f44.google.com with SMTP id t59so3160660yho.31 for ; Tue, 02 Jul 2013 07:29:31 -0700 (PDT) In-Reply-To: <1372747174-23580-1-git-send-email-fan.du@windriver.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 > --- > 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; > } > >