From 5be083cedc087b2d457ef2e9c2d5698c94d3d5e4 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 6 Mar 2017 15:57:31 -0800 Subject: [PATCH] net: ipv6: Remove redundant RTA_OIF in multipath routes Dinesh reported that RTA_MULTIPATH nexthops are 8-bytes larger with IPv6 than IPv4. The recent refactoring for multipath support in netlink messages does discriminate between non-multipath which needs the OIF and multipath which adds a rtnexthop struct for each hop making the RTA_OIF attribute redundant. Resolve by adding a flag to the info function to skip the oif for multipath. Fixes: beb1afac518d ("net: ipv6: Add support to dump multipath routes via RTA_MULTIPATH attribute") Reported-by: Dinesh Dutt Signed-off-by: David Ahern Signed-off-by: David S. Miller --- net/ipv6/route.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 229bfcc451ef..35c58b669ebd 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -3299,7 +3299,6 @@ static size_t rt6_nlmsg_size(struct rt6_info *rt) nexthop_len = nla_total_size(0) /* RTA_MULTIPATH */ + NLA_ALIGN(sizeof(struct rtnexthop)) + nla_total_size(16) /* RTA_GATEWAY */ - + nla_total_size(4) /* RTA_OIF */ + lwtunnel_get_encap_size(rt->dst.lwtstate); nexthop_len *= rt->rt6i_nsiblings; @@ -3323,7 +3322,7 @@ static size_t rt6_nlmsg_size(struct rt6_info *rt) } static int rt6_nexthop_info(struct sk_buff *skb, struct rt6_info *rt, - unsigned int *flags) + unsigned int *flags, bool skip_oif) { if (!netif_running(rt->dst.dev) || !netif_carrier_ok(rt->dst.dev)) { *flags |= RTNH_F_LINKDOWN; @@ -3336,7 +3335,8 @@ static int rt6_nexthop_info(struct sk_buff *skb, struct rt6_info *rt, goto nla_put_failure; } - if (rt->dst.dev && + /* not needed for multipath encoding b/c it has a rtnexthop struct */ + if (!skip_oif && rt->dst.dev && nla_put_u32(skb, RTA_OIF, rt->dst.dev->ifindex)) goto nla_put_failure; @@ -3350,6 +3350,7 @@ nla_put_failure: return -EMSGSIZE; } +/* add multipath next hop */ static int rt6_add_nexthop(struct sk_buff *skb, struct rt6_info *rt) { struct rtnexthop *rtnh; @@ -3362,7 +3363,7 @@ static int rt6_add_nexthop(struct sk_buff *skb, struct rt6_info *rt) rtnh->rtnh_hops = 0; rtnh->rtnh_ifindex = rt->dst.dev ? rt->dst.dev->ifindex : 0; - if (rt6_nexthop_info(skb, rt, &flags) < 0) + if (rt6_nexthop_info(skb, rt, &flags, true) < 0) goto nla_put_failure; rtnh->rtnh_flags = flags; @@ -3515,7 +3516,7 @@ static int rt6_fill_node(struct net *net, nla_nest_end(skb, mp); } else { - if (rt6_nexthop_info(skb, rt, &rtm->rtm_flags) < 0) + if (rt6_nexthop_info(skb, rt, &rtm->rtm_flags, false) < 0) goto nla_put_failure; }