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: Wed, 03 Jul 2013 09:23:03 -0400 Message-ID: <51D425B7.20204@gmail.com> References: <1372747174-23580-1-git-send-email-fan.du@windriver.com> <51D2E3C8.5050100@gmail.com> <51D389F9.4030804@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: nhorman@tuxdriver.com, nicolas.dichtel@6wind.com, davem@davemloft.net, netdev@vger.kernel.org To: Fan Du Return-path: Received: from mail-ye0-f174.google.com ([209.85.213.174]:42356 "EHLO mail-ye0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216Ab3GCNXH (ORCPT ); Wed, 3 Jul 2013 09:23:07 -0400 Received: by mail-ye0-f174.google.com with SMTP id m9so30724yen.19 for ; Wed, 03 Jul 2013 06:23:06 -0700 (PDT) In-Reply-To: <51D389F9.4030804@windriver.com> Sender: netdev-owner@vger.kernel.org List-ID: On 07/02/2013 10:18 PM, Fan Du wrote: > > > On 2013=E5=B9=B407=E6=9C=8802=E6=97=A5 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 ZER= O, >>> as a result ip6_dst_check always fail out. This behaviour makes >>> transport->dst useless, because every sctp_packet_transmit must loo= k >>> for valid dst(Is this what supposed to be?) >>> >>> One aggressive way is to call rt_genid_bump which invalid all dst t= o >>> 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] =3D 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 =3D NULL; >>> + >>> + if (t->dst) { >>> + struct rt6_info *rt =3D (struct rt6_info *)t->dst; >>> + u32 cookie =3D 0; >>> + >>> + if ((t->af_specific->sa_family =3D=3D AF_INET6) && rt->rt6i_node) >>> + cookie =3D rt->rt6i_node->fn_sernum; >>> + if (!dst_check(t->dst, cookie)) { >>> + dst_release(t->dst); >>> + t->dst =3D 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 tha= t, >> 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 =3D 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 =3D (struct rt6_info *)dst; > t->dst =3D dst; > + t->dst_cookie =3D rt->rt6i_node ? rt->rt6i_node->fn_s= ernum > : 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; >>> } >>> >>> >> >> >