From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [PATCH net-next 2/3 v2] net: ipv4 sysctl option to ignore routes when nexthop link is down Date: Wed, 10 Jun 2015 09:17:19 -0700 Message-ID: <5578630F.9070602@redhat.com> References: <1433918841-15576-1-git-send-email-gospo@cumulusnetworks.com> <1433918841-15576-3-git-send-email-gospo@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit To: Andy Gospodarek , netdev@vger.kernel.org, davem@davemloft.net, ddutt@cumulusnetworks.com, sfeldma@gmail.com, alexander.duyck@gmail.com, hannes@stressinduktion.org, stephen@networkplumber.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:48080 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933591AbbFJQRV (ORCPT ); Wed, 10 Jun 2015 12:17:21 -0400 In-Reply-To: <1433918841-15576-3-git-send-email-gospo@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 06/09/2015 11:47 PM, Andy Gospodarek wrote: > This feature is only enabled with the new per-interface or ipv4 global > sysctls called 'ignore_routes_with_linkdown'. > > net.ipv4.conf.all.ignore_routes_with_linkdown = 0 > net.ipv4.conf.default.ignore_routes_with_linkdown = 0 > net.ipv4.conf.lo.ignore_routes_with_linkdown = 0 > ... > > When the above sysctls are set, will report to userspace that a route is > dead and will no longer resolve to this nexthop when performing a fib > lookup. This will signal to userspace that the route will not be > selected. The signalling of a RTNH_F_DEAD is only passed to userspace > if the sysctl is enabled and link is down. This was done as without it the > netlink listeners would have no idea whether or not a nexthop would be > selected. The kernel only sets RTNH_F_DEAD internally if the inteface has > IFF_UP cleared. > > With the new sysctl set, the following behavior can be observed > (interface p8p1 is link-down): > > # ip route show > default via 10.0.5.2 dev p9p1 > 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 > 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 > 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 dead linkdown > 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 dead linkdown > 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 > # ip route get 90.0.0.1 > 90.0.0.1 via 70.0.0.2 dev p7p1 src 70.0.0.1 > cache > # ip route get 80.0.0.1 > local 80.0.0.1 dev lo src 80.0.0.1 > cache > # ip route get 80.0.0.2 > 80.0.0.2 via 10.0.5.2 dev p9p1 src 10.0.5.15 > cache > > While the route does remain in the table (so it can be modified if > needed rather than being wiped away as it would be if IFF_UP was > cleared), the proper next-hop is chosen automatically when the link is > down. Now interface p8p1 is linked-up: > > # ip route show > default via 10.0.5.2 dev p9p1 > 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 > 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 > 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 > 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 > 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 > 192.168.56.0/24 dev p2p1 proto kernel scope link src 192.168.56.2 > # ip route get 90.0.0.1 > 90.0.0.1 via 80.0.0.2 dev p8p1 src 80.0.0.1 > cache > # ip route get 80.0.0.1 > local 80.0.0.1 dev lo src 80.0.0.1 > cache > # ip route get 80.0.0.2 > 80.0.0.2 dev p8p1 src 80.0.0.1 > cache > > and the output changes to what one would expect. > > If the sysctl is not set, the following output would be expected when > p8p1 is down: > > # ip route show > default via 10.0.5.2 dev p9p1 > 10.0.5.0/24 dev p9p1 proto kernel scope link src 10.0.5.15 > 70.0.0.0/24 dev p7p1 proto kernel scope link src 70.0.0.1 > 80.0.0.0/24 dev p8p1 proto kernel scope link src 80.0.0.1 linkdown > 90.0.0.0/24 via 80.0.0.2 dev p8p1 metric 1 linkdown > 90.0.0.0/24 via 70.0.0.2 dev p7p1 metric 2 > > Since the dead flag does not appear, there should be no expectation that > the kernel would skip using this route due to link being down. > > v2: Split kernel changes into 2 patches, this actually makes a > behavioral change if the sysctl is set. Also took suggestion from Alex > to simplify code by only checking sysctl during fib lookup and > suggestion from Scott to add a per-interface sysctl. > > Signed-off-by: Andy Gospodarek > Signed-off-by: Dinesh Dutt > --- > include/linux/inetdevice.h | 3 +++ > include/net/fib_rules.h | 3 ++- > include/net/ip_fib.h | 17 ++++++++++------- > include/uapi/linux/ip.h | 1 + > include/uapi/linux/sysctl.h | 1 + > kernel/sysctl_binary.c | 1 + > net/ipv4/devinet.c | 2 ++ > net/ipv4/fib_frontend.c | 6 +++--- > net/ipv4/fib_rules.c | 5 +++-- > net/ipv4/fib_semantics.c | 28 ++++++++++++++++++++++------ > net/ipv4/fib_trie.c | 7 +++++++ > net/ipv4/netfilter/ipt_rpfilter.c | 2 +- > net/ipv4/route.c | 10 +++++----- > 13 files changed, 61 insertions(+), 25 deletions(-) > > diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h > index 0a21fbe..a4328ce 100644 > --- a/include/linux/inetdevice.h > +++ b/include/linux/inetdevice.h > @@ -120,6 +120,9 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev) > || (!IN_DEV_FORWARD(in_dev) && \ > IN_DEV_ORCONF((in_dev), ACCEPT_REDIRECTS))) > > +#define IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) \ > + IN_DEV_CONF_GET((in_dev), IGNORE_ROUTES_WITH_LINKDOWN) > + > #define IN_DEV_ARPFILTER(in_dev) IN_DEV_ORCONF((in_dev), ARPFILTER) > #define IN_DEV_ARP_ACCEPT(in_dev) IN_DEV_ORCONF((in_dev), ARP_ACCEPT) > #define IN_DEV_ARP_ANNOUNCE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_ANNOUNCE) > diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h > index 6d67383..903a55e 100644 > --- a/include/net/fib_rules.h > +++ b/include/net/fib_rules.h > @@ -36,7 +36,8 @@ struct fib_lookup_arg { > void *result; > struct fib_rule *rule; > int flags; > -#define FIB_LOOKUP_NOREF 1 > +#define FIB_LOOKUP_NOREF 1 > +#define FIB_LOOKUP_IGNORE_LINKSTATE 2 > }; > > struct fib_rules_ops { > diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h > index d1de1b7..854d790 100644 > --- a/include/net/ip_fib.h > +++ b/include/net/ip_fib.h > @@ -226,7 +226,7 @@ static inline struct fib_table *fib_new_table(struct net *net, u32 id) > } > > static inline int fib_lookup(struct net *net, const struct flowi4 *flp, > - struct fib_result *res) > + struct fib_result *res, unsigned int flags) > { > struct fib_table *tb; > int err = -ENETUNREACH; > @@ -234,7 +234,7 @@ static inline int fib_lookup(struct net *net, const struct flowi4 *flp, > rcu_read_lock(); > > tb = fib_get_table(net, RT_TABLE_MAIN); > - if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF)) > + if (tb && !fib_table_lookup(tb, flp, res, flags | FIB_LOOKUP_NOREF)) > err = 0; > > rcu_read_unlock(); > @@ -249,16 +249,17 @@ void __net_exit fib4_rules_exit(struct net *net); > struct fib_table *fib_new_table(struct net *net, u32 id); > struct fib_table *fib_get_table(struct net *net, u32 id); > > -int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res); > +int __fib_lookup(struct net *net, struct flowi4 *flp, > + struct fib_result *res, unsigned int flags); > > static inline int fib_lookup(struct net *net, struct flowi4 *flp, > - struct fib_result *res) > + struct fib_result *res, unsigned int flags) > { > struct fib_table *tb; > int err; > > if (net->ipv4.fib_has_custom_rules) > - return __fib_lookup(net, flp, res); > + return __fib_lookup(net, flp, res, flags | FIB_LOOKUP_NOREF); > > rcu_read_lock(); > > @@ -266,11 +267,13 @@ static inline int fib_lookup(struct net *net, struct flowi4 *flp, > > for (err = 0; !err; err = -ENETUNREACH) { > tb = rcu_dereference_rtnl(net->ipv4.fib_main); > - if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF)) > + if (tb && !fib_table_lookup(tb, flp, res, > + flags | FIB_LOOKUP_NOREF)) > break; > > tb = rcu_dereference_rtnl(net->ipv4.fib_default); > - if (tb && !fib_table_lookup(tb, flp, res, FIB_LOOKUP_NOREF)) > + if (tb && !fib_table_lookup(tb, flp, res, > + flags | FIB_LOOKUP_NOREF)) > break; > } > Instead of 3 lines w/ flags | FIB_LOOKUP_NOREF you could probably just do a flags |= FIB_LOOKUP_NOREF once and save yourself some trouble. > diff --git a/include/uapi/linux/ip.h b/include/uapi/linux/ip.h > index 4119594..08f894d 100644 > --- a/include/uapi/linux/ip.h > +++ b/include/uapi/linux/ip.h > @@ -164,6 +164,7 @@ enum > IPV4_DEVCONF_ROUTE_LOCALNET, > IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL, > IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL, > + IPV4_DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN, > __IPV4_DEVCONF_MAX > }; > > diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h > index 0956373..62fda94 100644 > --- a/include/uapi/linux/sysctl.h > +++ b/include/uapi/linux/sysctl.h > @@ -482,6 +482,7 @@ enum > NET_IPV4_CONF_PROMOTE_SECONDARIES=20, > NET_IPV4_CONF_ARP_ACCEPT=21, > NET_IPV4_CONF_ARP_NOTIFY=22, > + NET_IPV4_CONF_IGNORE_ROUTES_WITH_LINKDOWN=23, > }; > > /* /proc/sys/net/ipv4/netfilter */ > diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c > index 7e7746a..c9d0a0e 100644 > --- a/kernel/sysctl_binary.c > +++ b/kernel/sysctl_binary.c > @@ -253,6 +253,7 @@ static const struct bin_table bin_net_ipv4_conf_vars_table[] = { > { CTL_INT, NET_IPV4_CONF_NOPOLICY, "disable_policy" }, > { CTL_INT, NET_IPV4_CONF_FORCE_IGMP_VERSION, "force_igmp_version" }, > { CTL_INT, NET_IPV4_CONF_PROMOTE_SECONDARIES, "promote_secondaries" }, > + { CTL_INT, NET_IPV4_CONF_IGNORE_ROUTES_WITH_LINKDOWN, "ignore_routes_with_linkdown" }, > {} > }; > > diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c > index 419d23c..7498716 100644 > --- a/net/ipv4/devinet.c > +++ b/net/ipv4/devinet.c > @@ -2169,6 +2169,8 @@ static struct devinet_sysctl_table { > "igmpv2_unsolicited_report_interval"), > DEVINET_SYSCTL_RW_ENTRY(IGMPV3_UNSOLICITED_REPORT_INTERVAL, > "igmpv3_unsolicited_report_interval"), > + DEVINET_SYSCTL_RW_ENTRY(IGNORE_ROUTES_WITH_LINKDOWN, > + "ignore_routes_with_linkdown"), > > DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"), > DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"), > diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c > index 1e4c646..ead31c6 100644 > --- a/net/ipv4/fib_frontend.c > +++ b/net/ipv4/fib_frontend.c > @@ -280,7 +280,7 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb) > fl4.flowi4_tos = RT_TOS(ip_hdr(skb)->tos); > fl4.flowi4_scope = scope; > fl4.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0; > - if (!fib_lookup(net, &fl4, &res)) > + if (!fib_lookup(net, &fl4, &res, 0)) > return FIB_RES_PREFSRC(net, res); > } else { > scope = RT_SCOPE_LINK; > @@ -319,7 +319,7 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, > fl4.flowi4_mark = IN_DEV_SRC_VMARK(idev) ? skb->mark : 0; > > net = dev_net(dev); > - if (fib_lookup(net, &fl4, &res)) > + if (fib_lookup(net, &fl4, &res, 0)) > goto last_resort; > if (res.type != RTN_UNICAST && > (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev))) > @@ -354,7 +354,7 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, > fl4.flowi4_oif = dev->ifindex; > > ret = 0; > - if (fib_lookup(net, &fl4, &res) == 0) { > + if (fib_lookup(net, &fl4, &res, 0) == 0) { > if (res.type == RTN_UNICAST) > ret = FIB_RES_NH(res).nh_scope >= RT_SCOPE_HOST; > } The code for validating a source could probably ignore the LINKDOWN message. Otherwise we run the risk of a link flapping and confusing the source since the link is down but any Rx packets in the rings are being flushed. > diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c > index 5615198..18123d5 100644 > --- a/net/ipv4/fib_rules.c > +++ b/net/ipv4/fib_rules.c > @@ -47,11 +47,12 @@ struct fib4_rule { > #endif > }; > > -int __fib_lookup(struct net *net, struct flowi4 *flp, struct fib_result *res) > +int __fib_lookup(struct net *net, struct flowi4 *flp, > + struct fib_result *res, unsigned int flags) > { > struct fib_lookup_arg arg = { > .result = res, > - .flags = FIB_LOOKUP_NOREF, > + .flags = flags, > }; > int err; > > diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c > index 776e029..4dd709f 100644 > --- a/net/ipv4/fib_semantics.c > +++ b/net/ipv4/fib_semantics.c > @@ -623,7 +623,8 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi, > /* It is not necessary, but requires a bit of thinking */ > if (fl4.flowi4_scope < RT_SCOPE_LINK) > fl4.flowi4_scope = RT_SCOPE_LINK; > - err = fib_lookup(net, &fl4, &res); > + err = fib_lookup(net, &fl4, &res, > + FIB_LOOKUP_IGNORE_LINKSTATE); > if (err) { > rcu_read_unlock(); > return err; > @@ -1035,12 +1036,16 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, > nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc)) > goto nla_put_failure; > if (fi->fib_nhs == 1) { > + struct in_device *in_dev = __in_dev_get_rcu(fi->fib_nh->nh_dev); > if (fi->fib_nh->nh_gw && > nla_put_in_addr(skb, RTA_GATEWAY, fi->fib_nh->nh_gw)) > goto nla_put_failure; > if (fi->fib_nh->nh_oif && > nla_put_u32(skb, RTA_OIF, fi->fib_nh->nh_oif)) > goto nla_put_failure; > + if (in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && > + fi->fib_nh->nh_flags & RTNH_F_LINKDOWN) > + rtm->rtm_flags |= RTNH_F_DEAD; > #ifdef CONFIG_IP_ROUTE_CLASSID > if (fi->fib_nh[0].nh_tclassid && > nla_put_u32(skb, RTA_FLOW, fi->fib_nh[0].nh_tclassid)) > @@ -1057,11 +1062,16 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event, > goto nla_put_failure; > > for_nexthops(fi) { > + struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev); > rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh)); > if (!rtnh) > goto nla_put_failure; > > - rtnh->rtnh_flags = nh->nh_flags & 0xFF; > + if (in_dev && IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && > + nh->nh_flags & RTNH_F_LINKDOWN) > + rtnh->rtnh_flags = (nh->nh_flags | RTNH_F_DEAD) & 0xFF; > + else > + rtnh->rtnh_flags = nh->nh_flags & 0xFF; > rtnh->rtnh_hops = nh->nh_weight - 1; > rtnh->rtnh_ifindex = nh->nh_oif; > Why not just split this if into two seperate statments? One taking care of the first setting of rtnh_flags and then a second one ORing in the RTNH_F_DEAD. > @@ -1306,16 +1316,22 @@ int fib_sync_up(struct net_device *dev, unsigned int nh_flags) > void fib_select_multipath(struct fib_result *res) > { > struct fib_info *fi = res->fi; > + struct in_device *in_dev; > int w; > > spin_lock_bh(&fib_multipath_lock); > if (fi->fib_power <= 0) { > int power = 0; > change_nexthops(fi) { > - if (!(nexthop_nh->nh_flags & RTNH_F_DEAD)) { > - power += nexthop_nh->nh_weight; > - nexthop_nh->nh_power = nexthop_nh->nh_weight; > - } > + in_dev = __in_dev_get_rcu(nexthop_nh->nh_dev); > + if (nexthop_nh->nh_flags & RTNH_F_DEAD) > + continue; > + if (in_dev && > + IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && > + nexthop_nh->nh_flags & RTNH_F_LINKDOWN) > + continue; > + power += nexthop_nh->nh_weight; > + nexthop_nh->nh_power = nexthop_nh->nh_weight; > } endfor_nexthops(fi); > fi->fib_power = power; > if (power <= 0) { > diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c > index 3c699c4..f75ca20 100644 > --- a/net/ipv4/fib_trie.c > +++ b/net/ipv4/fib_trie.c > @@ -1407,11 +1407,18 @@ found: > } > if (fi->fib_flags & RTNH_F_DEAD) > continue; > + > for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) { > const struct fib_nh *nh = &fi->fib_nh[nhsel]; > + struct in_device *in_dev = __in_dev_get_rcu(nh->nh_dev); > > if (nh->nh_flags & RTNH_F_DEAD) > continue; > + if (in_dev && > + IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) && > + nh->nh_flags & RTNH_F_LINKDOWN && > + !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE)) > + continue; > if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif) > continue; > The order of checks should be: 1. (nh->nh_flags & RTNH_F_LINKDOWN) 2. !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE) 3. in_dev 4. IGNORE_ROUTES_WITH_LINKDOWN That way we don't waste time checking the in_dev if the link isn't reported as being down. Also I would probably move the whole block inside an if statement based off of the first 2 checks since nothing else is making use of in_dev. > diff --git a/net/ipv4/netfilter/ipt_rpfilter.c b/net/ipv4/netfilter/ipt_rpfilter.c > index 4bfaedf..250c633 100644 > --- a/net/ipv4/netfilter/ipt_rpfilter.c > +++ b/net/ipv4/netfilter/ipt_rpfilter.c > @@ -40,7 +40,7 @@ static bool rpfilter_lookup_reverse(struct flowi4 *fl4, > struct net *net = dev_net(dev); > int ret __maybe_unused; > > - if (fib_lookup(net, fl4, &res)) > + if (fib_lookup(net, fl4, &res, 0)) > return false; > > if (res.type != RTN_UNICAST) { Any rpfilter stuff can probably ignore the linkdown check since it is possible that a driver could be flushing data just after a link went down. > diff --git a/net/ipv4/route.c b/net/ipv4/route.c > index f605598..d0362a2 100644 > --- a/net/ipv4/route.c > +++ b/net/ipv4/route.c > @@ -747,7 +747,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow > if (!(n->nud_state & NUD_VALID)) { > neigh_event_send(n, NULL); > } else { > - if (fib_lookup(net, fl4, &res) == 0) { > + if (fib_lookup(net, fl4, &res, 0) == 0) { > struct fib_nh *nh = &FIB_RES_NH(res); > > update_or_create_fnhe(nh, fl4->daddr, new_gw, > @@ -975,7 +975,7 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) > return; > > rcu_read_lock(); > - if (fib_lookup(dev_net(dst->dev), fl4, &res) == 0) { > + if (fib_lookup(dev_net(dst->dev), fl4, &res, 0) == 0) { > struct fib_nh *nh = &FIB_RES_NH(res); > > update_or_create_fnhe(nh, fl4->daddr, 0, mtu, > @@ -1186,7 +1186,7 @@ void ip_rt_get_source(u8 *addr, struct sk_buff *skb, struct rtable *rt) > fl4.flowi4_mark = skb->mark; > > rcu_read_lock(); > - if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res) == 0) > + if (fib_lookup(dev_net(rt->dst.dev), &fl4, &res, 0) == 0) > src = FIB_RES_PREFSRC(dev_net(rt->dst.dev), res); > else > src = inet_select_addr(rt->dst.dev, > @@ -1716,7 +1716,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, > fl4.flowi4_scope = RT_SCOPE_UNIVERSE; > fl4.daddr = daddr; > fl4.saddr = saddr; > - err = fib_lookup(net, &fl4, &res); > + err = fib_lookup(net, &fl4, &res, 0); > if (err != 0) { > if (!IN_DEV_FORWARD(in_dev)) > err = -EHOSTUNREACH; > @@ -2123,7 +2123,7 @@ struct rtable *__ip_route_output_key(struct net *net, struct flowi4 *fl4) > goto make_route; > } > > - if (fib_lookup(net, fl4, &res)) { > + if (fib_lookup(net, fl4, &res, 0)) { > res.fi = NULL; > res.table = NULL; > if (fl4->flowi4_oif) { >