diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index 7375a165fd98da708084892e7edc8cca5d169199..82bced2fc1e3103c0a429ed6f6620168665c36a1 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -36,6 +36,7 @@ struct route_info { #define RT6_LOOKUP_F_SRCPREF_PUBLIC 0x00000010 #define RT6_LOOKUP_F_SRCPREF_COA 0x00000020 #define RT6_LOOKUP_F_IGNORE_LINKSTATE 0x00000040 +#define RT6_LOOKUP_F_DST_NOREF 0x00000080 /* We do not (yet ?) support IPv6 jumbograms (RFC 2675) * Unlike IPv4, hdr->seg_len doesn't include the IPv6 header diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 4c5142a30808a298b2e7479123143940a7665f6b..5469e0a9c81018106b0d3f91a2b8b1564cd48c7f 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -1391,9 +1391,6 @@ static struct rt6_info *rt6_get_pcpu_route(const struct fib6_result *res) pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu); - if (pcpu_rt) - ip6_hold_safe(NULL, &pcpu_rt); - return pcpu_rt; } @@ -1403,12 +1400,9 @@ static struct rt6_info *rt6_make_pcpu_route(struct net *net, struct rt6_info *pcpu_rt, *prev, **p; pcpu_rt = ip6_rt_pcpu_alloc(res); - if (!pcpu_rt) { - dst_hold(&net->ipv6.ip6_null_entry->dst); - return net->ipv6.ip6_null_entry; - } + if (!pcpu_rt) + return NULL; - dst_hold(&pcpu_rt->dst); p = this_cpu_ptr(res->nh->rt6i_pcpu); prev = cmpxchg(p, NULL, pcpu_rt); BUG_ON(prev); @@ -2189,9 +2183,12 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, const struct sk_buff *skb, int flags) { struct fib6_result res = {}; - struct rt6_info *rt; + struct rt6_info *rt = NULL; int strict = 0; + WARN_ON_ONCE((flags & RT6_LOOKUP_F_DST_NOREF) && + !rcu_read_lock_held()); + strict |= flags & RT6_LOOKUP_F_IFACE; strict |= flags & RT6_LOOKUP_F_IGNORE_LINKSTATE; if (net->ipv6.devconf_all->forwarding == 0) @@ -2200,23 +2197,15 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, rcu_read_lock(); fib6_table_lookup(net, table, oif, fl6, &res, strict); - if (res.f6i == net->ipv6.fib6_null_entry) { - rt = net->ipv6.ip6_null_entry; - rcu_read_unlock(); - dst_hold(&rt->dst); - return rt; - } + if (res.f6i == net->ipv6.fib6_null_entry) + goto out; fib6_select_path(net, &res, fl6, oif, false, skb, strict); /*Search through exception table */ rt = rt6_find_cached_rt(&res, &fl6->daddr, &fl6->saddr); if (rt) { - if (ip6_hold_safe(net, &rt)) - dst_use_noref(&rt->dst, jiffies); - - rcu_read_unlock(); - return rt; + goto out; } else if (unlikely((fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH) && !res.nh->fib_nh_gw_family)) { /* Create a RTF_CACHE clone which will not be @@ -2224,40 +2213,38 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, * the daddr in the skb during the neighbor look-up is different * from the fl6->daddr used to look-up route here. */ - struct rt6_info *uncached_rt; + rt = ip6_rt_cache_alloc(&res, &fl6->daddr, NULL); - uncached_rt = ip6_rt_cache_alloc(&res, &fl6->daddr, NULL); - - rcu_read_unlock(); - - if (uncached_rt) { - /* Uncached_rt's refcnt is taken during ip6_rt_cache_alloc() - * No need for another dst_hold() + if (rt) { + /* 1 refcnt is taken during ip6_rt_cache_alloc(). + * As rt6_uncached_list_add() does not consume refcnt, + * this refcnt is always returned to the caller even + * if caller sets RT6_LOOKUP_F_DST_NOREF flag. */ - rt6_uncached_list_add(uncached_rt); + rt6_uncached_list_add(rt); atomic_inc(&net->ipv6.rt6_stats->fib_rt_uncache); - } else { - uncached_rt = net->ipv6.ip6_null_entry; - dst_hold(&uncached_rt->dst); - } + rcu_read_unlock(); - return uncached_rt; + return rt; + } } else { /* Get a percpu copy */ - - struct rt6_info *pcpu_rt; - local_bh_disable(); - pcpu_rt = rt6_get_pcpu_route(&res); + rt = rt6_get_pcpu_route(&res); - if (!pcpu_rt) - pcpu_rt = rt6_make_pcpu_route(net, &res); + if (!rt) + rt = rt6_make_pcpu_route(net, &res); local_bh_enable(); - rcu_read_unlock(); - - return pcpu_rt; } +out: + if (!rt) + rt = net->ipv6.ip6_null_entry; + if (!(flags & RT6_LOOKUP_F_DST_NOREF)) + ip6_hold_safe(net, &rt); + rcu_read_unlock(); + + return rt; } EXPORT_SYMBOL_GPL(ip6_pol_route);