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ipv6: honor RT6_LOOKUP_F_DST_NOREF in rule lookup logic

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This patch specifically converts the rule lookup logic to honor this
flag and not release refcnt when traversing each rule and calling
lookup() on each routing table.
Similar to previous patch, we also need some special handling of dst
entries in uncached list because there is always 1 refcnt taken for them
even if RT6_LOOKUP_F_DST_NOREF flag is set.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wei Wang 2019-06-20 17:36:39 -07:00 committed by David S. Miller
parent 74109218b0
commit d64a1f574a
3 changed files with 20 additions and 7 deletions
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10
include/net/ip6_route.h
View File

@ -94,6 +94,16 @@ static inline struct dst_entry *ip6_route_output(struct net *net,
return ip6_route_output_flags(net, sk, fl6, 0);
}
/* Only conditionally release dst if flags indicates
* !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list.
*/
static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags)
{
if (!(flags & RT6_LOOKUP_F_DST_NOREF) ||
!list_empty(&rt->rt6i_uncached))
ip6_rt_put(rt);
}
struct dst_entry *ip6_route_lookup(struct net *net, struct flowi6 *fl6,
const struct sk_buff *skb, int flags);
struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,

12
net/ipv6/fib6_rules.c
View File

@ -113,14 +113,15 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
rt = lookup(net, net->ipv6.fib6_local_tbl, fl6, skb, flags);
if (rt != net->ipv6.ip6_null_entry && rt->dst.error != -EAGAIN)
return &rt->dst;
ip6_rt_put(rt);
ip6_rt_put_flags(rt, flags);
rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
if (rt->dst.error != -EAGAIN)
return &rt->dst;
ip6_rt_put(rt);
ip6_rt_put_flags(rt, flags);
}
dst_hold(&net->ipv6.ip6_null_entry->dst);
if (!(flags & RT6_LOOKUP_F_DST_NOREF))
dst_hold(&net->ipv6.ip6_null_entry->dst);
return &net->ipv6.ip6_null_entry->dst;
}
@ -237,13 +238,14 @@ static int __fib6_rule_action(struct fib_rule *rule, struct flowi *flp,
goto out;
}
again:
ip6_rt_put(rt);
ip6_rt_put_flags(rt, flags);
err = -EAGAIN;
rt = NULL;
goto out;
discard_pkt:
dst_hold(&rt->dst);
if (!(flags & RT6_LOOKUP_F_DST_NOREF))
dst_hold(&rt->dst);
out:
res->rt6 = rt;
return err;

5
net/ipv6/ip6_fib.c
View File

@ -316,9 +316,10 @@ struct dst_entry *fib6_rule_lookup(struct net *net, struct flowi6 *fl6,
rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
if (rt->dst.error == -EAGAIN) {
ip6_rt_put(rt);
ip6_rt_put_flags(rt, flags);
rt = net->ipv6.ip6_null_entry;
dst_hold(&rt->dst);
if (!(flags | RT6_LOOKUP_F_DST_NOREF))
dst_hold(&rt->dst);
}
return &rt->dst;