From 35103d11173b8fea874183f8aa508ae71234d299 Mon Sep 17 00:00:00 2001 From: Andy Gospodarek Date: Thu, 13 Aug 2015 10:39:01 -0400 Subject: [PATCH] net: ipv6 sysctl option to ignore routes when nexthop link is down Like the ipv4 patch with a similar title, this adds a sysctl to allow the user to change routing behavior based on whether or not the interface associated with the nexthop was an up or down link. The default setting preserves the current behavior, but anyone that enables it will notice that nexthops on down interfaces will no longer be selected: net.ipv6.conf.all.ignore_routes_with_linkdown = 0 net.ipv6.conf.default.ignore_routes_with_linkdown = 0 net.ipv6.conf.lo.ignore_routes_with_linkdown = 0 ... When the above sysctls are set, not only will link status be reported to userspace, but an indication that a nexthop is dead and will not be used is also reported. 1000::/8 via 7000::2 dev p7p1 metric 1024 dead linkdown pref medium 1000::/8 via 8000::2 dev p8p1 metric 1024 pref medium 7000::/8 dev p7p1 proto kernel metric 256 dead linkdown pref medium 8000::/8 dev p8p1 proto kernel metric 256 pref medium 9000::/8 via 8000::2 dev p8p1 metric 2048 pref medium 9000::/8 via 7000::2 dev p7p1 metric 1024 dead linkdown pref medium fe80::/64 dev p7p1 proto kernel metric 256 dead linkdown pref medium fe80::/64 dev p8p1 proto kernel metric 256 pref medium This also adds devconf support and notification when sysctl values change. v2: drop use of rt6i_nhflags since it is not needed right now Signed-off-by: Andy Gospodarek Signed-off-by: Dinesh Dutt Signed-off-by: David S. Miller --- include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + net/ipv6/addrconf.c | 105 +++++++++++++++++++++++++++++++++++++- net/ipv6/route.c | 11 +++- 4 files changed, 116 insertions(+), 2 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index cb9dcad72372..f1f32af6d9b9 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -31,6 +31,7 @@ struct ipv6_devconf { __s32 accept_ra_defrtr; __s32 accept_ra_min_hop_limit; __s32 accept_ra_pinfo; + __s32 ignore_routes_with_linkdown; #ifdef CONFIG_IPV6_ROUTER_PREF __s32 accept_ra_rtr_pref; __s32 rtr_probe_interval; diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index 80f3b74446a1..38b4fef20219 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -173,6 +173,7 @@ enum { DEVCONF_STABLE_SECRET, DEVCONF_USE_OIF_ADDRS_ONLY, DEVCONF_ACCEPT_RA_MIN_HOP_LIMIT, + DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN, DEVCONF_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 53e3a9d756b0..5dfbac72f1ab 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -214,6 +214,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .initialized = false, }, .use_oif_addrs_only = 0, + .ignore_routes_with_linkdown = 0, }; static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { @@ -257,6 +258,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .initialized = false, }, .use_oif_addrs_only = 0, + .ignore_routes_with_linkdown = 0, }; /* Check if a valid qdisc is available */ @@ -472,6 +474,9 @@ static int inet6_netconf_msgsize_devconf(int type) if (type == -1 || type == NETCONFA_PROXY_NEIGH) size += nla_total_size(4); + if (type == -1 || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) + size += nla_total_size(4); + return size; } @@ -508,6 +513,11 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, nla_put_s32(skb, NETCONFA_PROXY_NEIGH, devconf->proxy_ndp) < 0) goto nla_put_failure; + if ((type == -1 || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) && + nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, + devconf->ignore_routes_with_linkdown) < 0) + goto nla_put_failure; + nlmsg_end(skb, nlh); return 0; @@ -544,6 +554,7 @@ static const struct nla_policy devconf_ipv6_policy[NETCONFA_MAX+1] = { [NETCONFA_IFINDEX] = { .len = sizeof(int) }, [NETCONFA_FORWARDING] = { .len = sizeof(int) }, [NETCONFA_PROXY_NEIGH] = { .len = sizeof(int) }, + [NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN] = { .len = sizeof(int) }, }; static int inet6_netconf_get_devconf(struct sk_buff *in_skb, @@ -766,6 +777,63 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int newf) rt6_purge_dflt_routers(net); return 1; } + +static void addrconf_linkdown_change(struct net *net, __s32 newf) +{ + struct net_device *dev; + struct inet6_dev *idev; + + for_each_netdev(net, dev) { + idev = __in6_dev_get(dev); + if (idev) { + int changed = (!idev->cnf.ignore_routes_with_linkdown) ^ (!newf); + + idev->cnf.ignore_routes_with_linkdown = newf; + if (changed) + inet6_netconf_notify_devconf(dev_net(dev), + NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, + dev->ifindex, + &idev->cnf); + } + } +} + +static int addrconf_fixup_linkdown(struct ctl_table *table, int *p, int newf) +{ + struct net *net; + int old; + + if (!rtnl_trylock()) + return restart_syscall(); + + net = (struct net *)table->extra2; + old = *p; + *p = newf; + + if (p == &net->ipv6.devconf_dflt->ignore_routes_with_linkdown) { + if ((!newf) ^ (!old)) + inet6_netconf_notify_devconf(net, + NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, + NETCONFA_IFINDEX_DEFAULT, + net->ipv6.devconf_dflt); + rtnl_unlock(); + return 0; + } + + if (p == &net->ipv6.devconf_all->ignore_routes_with_linkdown) { + net->ipv6.devconf_dflt->ignore_routes_with_linkdown = newf; + addrconf_linkdown_change(net, newf); + if ((!newf) ^ (!old)) + inet6_netconf_notify_devconf(net, + NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, + NETCONFA_IFINDEX_ALL, + net->ipv6.devconf_all); + } + rtnl_unlock(); + + return 1; +} + #endif /* Nobody refers to this ifaddr, destroy it */ @@ -4616,6 +4684,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc; array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local; array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu; + array[DEVCONF_IGNORE_ROUTES_WITH_LINKDOWN] = cnf->ignore_routes_with_linkdown; /* we omit DEVCONF_STABLE_SECRET for now */ array[DEVCONF_USE_OIF_ADDRS_ONLY] = cnf->use_oif_addrs_only; } @@ -5338,6 +5407,34 @@ out: return err; } +static +int addrconf_sysctl_ignore_routes_with_linkdown(struct ctl_table *ctl, + int write, + void __user *buffer, + size_t *lenp, + loff_t *ppos) +{ + int *valp = ctl->data; + int val = *valp; + loff_t pos = *ppos; + struct ctl_table lctl; + int ret; + + /* ctl->data points to idev->cnf.ignore_routes_when_linkdown + * we should not modify it until we get the rtnl lock. + */ + lctl = *ctl; + lctl.data = &val; + + ret = proc_dointvec(&lctl, write, buffer, lenp, ppos); + + if (write) + ret = addrconf_fixup_linkdown(ctl, valp, val); + if (ret) + *ppos = pos; + return ret; +} + static struct addrconf_sysctl_table { struct ctl_table_header *sysctl_header; @@ -5629,7 +5726,13 @@ static struct addrconf_sysctl_table .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec, - + }, + { + .procname = "ignore_routes_with_linkdown", + .data = &ipv6_devconf.ignore_routes_with_linkdown, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = addrconf_sysctl_ignore_routes_with_linkdown, }, { /* sentinel */ diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 370f72785385..1c0217e61357 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -665,6 +665,12 @@ static struct rt6_info *find_match(struct rt6_info *rt, int oif, int strict, { int m; bool match_do_rr = false; + struct inet6_dev *idev = rt->rt6i_idev; + struct net_device *dev = rt->dst.dev; + + if (dev && !netif_carrier_ok(dev) && + idev->cnf.ignore_routes_with_linkdown) + goto out; if (rt6_check_expired(rt)) goto out; @@ -2887,8 +2893,11 @@ static int rt6_fill_node(struct net *net, else rtm->rtm_type = RTN_UNICAST; rtm->rtm_flags = 0; - if (!netif_carrier_ok(rt->dst.dev)) + if (!netif_carrier_ok(rt->dst.dev)) { rtm->rtm_flags |= RTNH_F_LINKDOWN; + if (rt->rt6i_idev->cnf.ignore_routes_with_linkdown) + rtm->rtm_flags |= RTNH_F_DEAD; + } rtm->rtm_scope = RT_SCOPE_UNIVERSE; rtm->rtm_protocol = rt->rt6i_protocol; if (rt->rt6i_flags & RTF_DYNAMIC) -- 2.30.2