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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: beb1afac51 ("net: ipv6: Add support to dump multipath routes
       via RTA_MULTIPATH attribute")
Reported-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
David Ahern 2017-03-06 15:57:31 -08:00 committed by David S. Miller
parent 713c43b315
commit 5be083cedc
1 changed files with 6 additions and 5 deletions
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11
net/ipv6/route.c
View File

@ -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;
}