From 0ae8133586ad1c9be894411aaf8b17bb58c8efe5 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 2 Feb 2017 12:37:08 -0800 Subject: [PATCH] net: ipv6: Allow shorthand delete of all nexthops in multipath route IPv4 allows multipath routes to be deleted using just the prefix and length. For example: $ ip ro ls vrf red unreachable default metric 8192 1.1.1.0/24 nexthop via 10.100.1.254 dev eth1 weight 1 nexthop via 10.11.200.2 dev eth11.200 weight 1 10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3 10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3 $ ip ro del 1.1.1.0/24 vrf red $ ip ro ls vrf red unreachable default metric 8192 10.11.200.0/24 dev eth11.200 proto kernel scope link src 10.11.200.3 10.100.1.0/24 dev eth1 proto kernel scope link src 10.100.1.3 The same notation does not work with IPv6 because of how multipath routes are implemented for IPv6. For IPv6 only the first nexthop of a multipath route is deleted if the request contains only a prefix and length. This leads to unnecessary complexity in userspace dealing with IPv6 multipath routes. This patch allows all nexthops to be deleted without specifying each one in the delete request. Internally, this is done by walking the sibling list of the route matching the specifications given (prefix, length, metric, protocol, etc). $ ip -6 ro ls vrf red 2001:db8:1::/120 dev eth1 proto kernel metric 256 pref medium 2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium 2001:db8:200::/120 via 2001:db8:1::2 dev eth1 metric 1024 pref medium 2001:db8:200::/120 via 2001:db8:2::2 dev eth2 metric 1024 pref medium ... $ ip -6 ro del vrf red 2001:db8:200::/120 $ ip -6 ro ls vrf red 2001:db8:1::/120 dev eth1 proto kernel metric 256 pref medium 2001:db8:2::/120 dev eth2 proto kernel metric 256 pref medium ... Because IPv6 allows individual nexthops to be deleted without deleting the entire route, the ip6_route_multipath_del and non-multipath code path (ip6_route_del) have to be discriminated so that all nexthops are only deleted for the latter case. This is done by making the existing fc_type in fib6_config a u16 and then adding a new u16 field with fc_delete_all_nh as the first bit. Suggested-by: Dinesh Dutt Signed-off-by: David Ahern Signed-off-by: David S. Miller --- include/net/ip6_fib.h | 4 +++- net/ipv6/route.c | 38 ++++++++++++++++++++++++++++++++++++-- 2 files changed, 39 insertions(+), 3 deletions(-) diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index a74e2aa40ef4..c979c878df1c 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -37,7 +37,9 @@ struct fib6_config { int fc_ifindex; u32 fc_flags; u32 fc_protocol; - u32 fc_type; /* only 8 bits are used */ + u16 fc_type; /* only 8 bits are used */ + u16 fc_delete_all_nh : 1, + __unused : 15; struct in6_addr fc_dst; struct in6_addr fc_src; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 91eb3f7782dd..635b7fdef2eb 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2143,6 +2143,34 @@ int ip6_del_rt(struct rt6_info *rt) return __ip6_del_rt(rt, &info); } +static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) +{ + struct nl_info *info = &cfg->fc_nlinfo; + struct fib6_table *table; + int err; + + table = rt->rt6i_table; + write_lock_bh(&table->tb6_lock); + + if (rt->rt6i_nsiblings && cfg->fc_delete_all_nh) { + struct rt6_info *sibling, *next_sibling; + + list_for_each_entry_safe(sibling, next_sibling, + &rt->rt6i_siblings, + rt6i_siblings) { + err = fib6_del(sibling, info); + if (err) + goto out; + } + } + + err = fib6_del(rt, info); +out: + write_unlock_bh(&table->tb6_lock); + ip6_rt_put(rt); + return err; +} + static int ip6_route_del(struct fib6_config *cfg) { struct fib6_table *table; @@ -2179,7 +2207,11 @@ static int ip6_route_del(struct fib6_config *cfg) dst_hold(&rt->dst); read_unlock_bh(&table->tb6_lock); - return __ip6_del_rt(rt, &cfg->fc_nlinfo); + /* if gateway was specified only delete the one hop */ + if (cfg->fc_flags & RTF_GATEWAY) + return __ip6_del_rt(rt, &cfg->fc_nlinfo); + + return __ip6_del_rt_siblings(rt, cfg); } } read_unlock_bh(&table->tb6_lock); @@ -3142,8 +3174,10 @@ static int inet6_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh) if (cfg.fc_mp) return ip6_route_multipath_del(&cfg); - else + else { + cfg.fc_delete_all_nh = 1; return ip6_route_del(&cfg); + } } static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh) -- 2.20.1