From d64a1f574a2957b4bcb06452d36cc1c6bf16e9fc Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Thu, 20 Jun 2019 17:36:39 -0700 Subject: [PATCH] ipv6: honor RT6_LOOKUP_F_DST_NOREF in rule lookup logic 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 Signed-off-by: David S. Miller --- include/net/ip6_route.h | 10 ++++++++++ net/ipv6/fib6_rules.c | 12 +++++++----- net/ipv6/ip6_fib.c | 5 +++-- 3 files changed, 20 insertions(+), 7 deletions(-) diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 82bced2fc1e3..0709835c01ad 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -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, diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c index bcfae13409b5..d22b6c140f23 100644 --- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -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; diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 1d16a01eccf5..5b1c9b5b9247 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -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;