[PATCH net-next v2 17/21] net/ipv6: Cleanup exception and cache route handling
From: David Ahern <hidden>
Date: 2018-04-18 00:34:01
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
IPv6 FIB will only contain FIB entries with exception routes added to the FIB entry. Once this transformation is complete, FIB lookups will return a fib6_info with the lookup functions still returning a dst based rt6_info. The current code uses rt6_info for both paths and overloads the rt6_info variable usually called 'rt'. This patch introduces a new 'f6i' variable name for the result of the FIB lookup and keeps 'rt' as the dst based return variable. 'f6i' becomes a fib6_info in a later patch which is why it is introduced as f6i now; avoids the additional churn in the later patch. In addition, remove RTF_CACHE and dst checks from fib6 add and delete since they can not happen now and will never happen after the data type flip. Signed-off-by: David Ahern <redacted> --- include/net/ip6_route.h | 1 - net/ipv6/ip6_fib.c | 16 +----- net/ipv6/route.c | 142 +++++++++++++++++++++++++++--------------------- 3 files changed, 81 insertions(+), 78 deletions(-)
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index ff70266e30d7..686cdc7f356a 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h@@ -106,7 +106,6 @@ int ip6_ins_rt(struct net *net, struct rt6_info *rt); int ip6_del_rt(struct net *net, struct rt6_info *rt); void rt6_flush_exceptions(struct rt6_info *rt); -int rt6_remove_exception_rt(struct rt6_info *rt); void rt6_age_exceptions(struct rt6_info *rt, struct fib6_gc_args *gc_args, unsigned long now);
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 280b69497ad0..53df4a98a7f7 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c@@ -1074,7 +1074,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, static void fib6_start_gc(struct net *net, struct rt6_info *rt) { if (!timer_pending(&net->ipv6.ip6_fib_timer) && - (rt->rt6i_flags & (RTF_EXPIRES | RTF_CACHE))) + (rt->rt6i_flags & RTF_EXPIRES)) mod_timer(&net->ipv6.ip6_fib_timer, jiffies + net->ipv6.sysctl.ip6_rt_gc_interval); }
@@ -1125,8 +1125,6 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, if (WARN_ON_ONCE(!atomic_read(&rt->dst.__refcnt))) return -EINVAL; - if (WARN_ON_ONCE(rt->rt6i_flags & RTF_CACHE)) - return -EINVAL; if (info->nlh) { if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
@@ -1650,8 +1648,6 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, RT6_TRACE("fib6_del_route\n"); - WARN_ON_ONCE(rt->rt6i_flags & RTF_CACHE); - /* Unlink it */ *rtp = rt->rt6_next; rt->rt6i_node = NULL;
@@ -1720,21 +1716,11 @@ int fib6_del(struct rt6_info *rt, struct nl_info *info) struct rt6_info __rcu **rtp; struct rt6_info __rcu **rtp_next; -#if RT6_DEBUG >= 2 - if (rt->dst.obsolete > 0) { - WARN_ON(fn); - return -ENOENT; - } -#endif if (!fn || rt == net->ipv6.fib6_null_entry) return -ENOENT; WARN_ON(!(fn->fn_flags & RTN_RTINFO)); - /* remove cached dst from exception table */ - if (rt->rt6i_flags & RTF_CACHE) - return rt6_remove_exception_rt(rt); - /* * Walk the leaf entries looking for ourself */
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 56a854b426a6..ad9eaecf539c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c@@ -1013,8 +1013,8 @@ static void rt6_set_from(struct rt6_info *rt, struct rt6_info *from) BUG_ON(from->from); rt->rt6i_flags &= ~RTF_EXPIRES; - dst_hold(&from->dst); - rt->from = from; + if (dst_hold_safe(&from->dst)) + rt->from = from; dst_init_metrics(&rt->dst, from->fib6_metrics->metrics, true); if (from->fib6_metrics != &dst_default_metrics) { rt->dst._metrics |= DST_METRICS_REFCOUNTED;
@@ -1097,8 +1097,9 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net, const struct sk_buff *skb, int flags) { - struct rt6_info *rt, *rt_cache; + struct rt6_info *f6i; struct fib6_node *fn; + struct rt6_info *rt; if (fl6->flowi6_flags & FLOWI_FLAG_SKIP_NH_OIF) flags &= ~RT6_LOOKUP_F_IFACE;
@@ -1106,36 +1107,36 @@ static struct rt6_info *ip6_pol_route_lookup(struct net *net, rcu_read_lock(); fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr); restart: - rt = rcu_dereference(fn->leaf); - if (!rt) { - rt = net->ipv6.fib6_null_entry; + f6i = rcu_dereference(fn->leaf); + if (!f6i) { + f6i = net->ipv6.fib6_null_entry; } else { - rt = rt6_device_match(net, rt, &fl6->saddr, + f6i = rt6_device_match(net, f6i, &fl6->saddr, fl6->flowi6_oif, flags); - if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0) - rt = rt6_multipath_select(net, rt, fl6, fl6->flowi6_oif, - skb, flags); + if (f6i->rt6i_nsiblings && fl6->flowi6_oif == 0) + f6i = rt6_multipath_select(net, f6i, fl6, + fl6->flowi6_oif, skb, flags); } - if (rt == net->ipv6.fib6_null_entry) { + if (f6i == net->ipv6.fib6_null_entry) { fn = fib6_backtrack(fn, &fl6->saddr); if (fn) goto restart; } + /* Search through exception table */ - rt_cache = rt6_find_cached_rt(rt, &fl6->daddr, &fl6->saddr); - if (rt_cache) { - rt = rt_cache; + rt = rt6_find_cached_rt(f6i, &fl6->daddr, &fl6->saddr); + if (rt) { if (ip6_hold_safe(net, &rt, true)) dst_use_noref(&rt->dst, jiffies); - } else if (dst_hold_safe(&rt->dst)) { - struct rt6_info *nrt; - - nrt = ip6_create_rt_rcu(rt); - dst_release(&rt->dst); - rt = nrt; - } else { + } else if (f6i == net->ipv6.fib6_null_entry) { rt = net->ipv6.ip6_null_entry; dst_hold(&rt->dst); + } else { + rt = ip6_create_rt_rcu(f6i); + if (!rt) { + rt = net->ipv6.ip6_null_entry; + dst_hold(&rt->dst); + } } rcu_read_unlock();
@@ -1218,9 +1219,6 @@ static struct rt6_info *ip6_rt_cache_alloc(struct rt6_info *ort, * Clone the route. */ - if (ort->rt6i_flags & (RTF_CACHE | RTF_PCPU)) - ort = ort->from; - rcu_read_lock(); dev = ip6_rt_get_dev_rcu(ort); rt = __ip6_dst_alloc(dev_net(dev), dev, 0);
@@ -1446,11 +1444,6 @@ static int rt6_insert_exception(struct rt6_info *nrt, struct rt6_exception *rt6_ex; int err = 0; - /* ort can't be a cache or pcpu route */ - if (ort->rt6i_flags & (RTF_CACHE | RTF_PCPU)) - ort = ort->from; - WARN_ON_ONCE(ort->rt6i_flags & (RTF_CACHE | RTF_PCPU)); - spin_lock_bh(&rt6_exception_lock); if (ort->exception_bucket_flushed) {
@@ -1589,7 +1582,7 @@ static struct rt6_info *rt6_find_cached_rt(struct rt6_info *rt, } /* Remove the passed in cached rt from the hash table that contains it */ -int rt6_remove_exception_rt(struct rt6_info *rt) +static int rt6_remove_exception_rt(struct rt6_info *rt) { struct rt6_exception_bucket *bucket; struct rt6_info *from = rt->from;
@@ -1854,7 +1847,8 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, const struct sk_buff *skb, int flags) { struct fib6_node *fn, *saved_fn; - struct rt6_info *rt, *rt_cache; + struct rt6_info *f6i; + struct rt6_info *rt; int strict = 0; strict |= flags & RT6_LOOKUP_F_IFACE;
@@ -1871,10 +1865,10 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, oif = 0; redo_rt6_select: - rt = rt6_select(net, fn, oif, strict); - if (rt->rt6i_nsiblings) - rt = rt6_multipath_select(net, rt, fl6, oif, skb, strict); - if (rt == net->ipv6.fib6_null_entry) { + f6i = rt6_select(net, fn, oif, strict); + if (f6i->rt6i_nsiblings) + f6i = rt6_multipath_select(net, f6i, fl6, oif, skb, strict); + if (f6i == net->ipv6.fib6_null_entry) { fn = fib6_backtrack(fn, &fl6->saddr); if (fn) goto redo_rt6_select;
@@ -1886,18 +1880,17 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, } } - /*Search through exception table */ - rt_cache = rt6_find_cached_rt(rt, &fl6->daddr, &fl6->saddr); - if (rt_cache) - rt = rt_cache; - - if (rt == net->ipv6.fib6_null_entry) { + if (f6i == net->ipv6.fib6_null_entry) { rt = net->ipv6.ip6_null_entry; rcu_read_unlock(); dst_hold(&rt->dst); trace_fib6_table_lookup(net, rt, table, fl6); return rt; - } else if (rt->rt6i_flags & RTF_CACHE) { + } + + /*Search through exception table */ + rt = rt6_find_cached_rt(f6i, &fl6->daddr, &fl6->saddr); + if (rt) { if (ip6_hold_safe(net, &rt, true)) dst_use_noref(&rt->dst, jiffies);
@@ -1905,7 +1898,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, trace_fib6_table_lookup(net, rt, table, fl6); return rt; } else if (unlikely((fl6->flowi6_flags & FLOWI_FLAG_KNOWN_NH) && - !(rt->rt6i_flags & RTF_GATEWAY))) { + !(f6i->rt6i_flags & RTF_GATEWAY))) { /* Create a RTF_CACHE clone which will not be * owned by the fib6 tree. It is for the special case where * the daddr in the skb during the neighbor look-up is different
@@ -1914,16 +1907,16 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, struct rt6_info *uncached_rt; - if (ip6_hold_safe(net, &rt, true)) { - dst_use_noref(&rt->dst, jiffies); + if (ip6_hold_safe(net, &f6i, true)) { + dst_use_noref(&f6i->dst, jiffies); } else { rcu_read_unlock(); - uncached_rt = rt; + uncached_rt = f6i; goto uncached_rt_out; } rcu_read_unlock(); - uncached_rt = ip6_rt_cache_alloc(rt, &fl6->daddr, NULL); + uncached_rt = ip6_rt_cache_alloc(f6i, &fl6->daddr, NULL); dst_release(&rt->dst); if (uncached_rt) {
@@ -1946,18 +1939,18 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table, struct rt6_info *pcpu_rt; - dst_use_noref(&rt->dst, jiffies); + dst_use_noref(&f6i->dst, jiffies); local_bh_disable(); - pcpu_rt = rt6_get_pcpu_route(rt); + pcpu_rt = rt6_get_pcpu_route(f6i); if (!pcpu_rt) { /* atomic_inc_not_zero() is needed when using rcu */ - if (atomic_inc_not_zero(&rt->rt6i_ref)) { + if (atomic_inc_not_zero(&f6i->rt6i_ref)) { /* No dst_hold() on rt is needed because grabbing * rt->rt6i_ref makes sure rt can't be released. */ - pcpu_rt = rt6_make_pcpu_route(net, rt); - rt6_release(rt); + pcpu_rt = rt6_make_pcpu_route(net, f6i); + rt6_release(f6i); } else { /* rt is already removed from tree */ pcpu_rt = net->ipv6.ip6_null_entry;
@@ -2419,7 +2412,8 @@ static struct rt6_info *__ip6_route_redirect(struct net *net, int flags) { struct ip6rd_flowi *rdfl = (struct ip6rd_flowi *)fl6; - struct rt6_info *rt, *rt_cache; + struct rt6_info *ret = NULL, *rt_cache; + struct rt6_info *rt; struct fib6_node *fn; /* Get the "current" route for this destination and
@@ -2458,7 +2452,7 @@ static struct rt6_info *__ip6_route_redirect(struct net *net, if (rt_cache && ipv6_addr_equal(&rdfl->gateway, &rt_cache->rt6i_gateway)) { - rt = rt_cache; + ret = rt_cache; break; } continue;
@@ -2469,7 +2463,7 @@ static struct rt6_info *__ip6_route_redirect(struct net *net, if (!rt) rt = net->ipv6.fib6_null_entry; else if (rt->rt6i_flags & RTF_REJECT) { - rt = net->ipv6.ip6_null_entry; + ret = net->ipv6.ip6_null_entry; goto out; }
@@ -2480,12 +2474,15 @@ static struct rt6_info *__ip6_route_redirect(struct net *net, } out: - ip6_hold_safe(net, &rt, true); + if (ret) + dst_hold(&ret->dst); + else + ret = ip6_create_rt_rcu(rt); rcu_read_unlock(); - trace_fib6_table_lookup(net, rt, table, fl6); - return rt; + trace_fib6_table_lookup(net, ret, table, fl6); + return ret; }; static struct dst_entry *ip6_route_redirect(struct net *net,
@@ -3182,6 +3179,22 @@ static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) return err; } +static int ip6_del_cached_rt(struct rt6_info *rt, struct fib6_config *cfg) +{ + int rc = -ESRCH; + + if (cfg->fc_ifindex && rt->dst.dev->ifindex != cfg->fc_ifindex) + goto out; + + if (cfg->fc_flags & RTF_GATEWAY && + !ipv6_addr_equal(&cfg->fc_gateway, &rt->rt6i_gateway)) + goto out; + if (dst_hold_safe(&rt->dst)) + rc = rt6_remove_exception_rt(rt); +out: + return rc; +} + static int ip6_route_del(struct fib6_config *cfg, struct netlink_ext_ack *extack) {
@@ -3206,11 +3219,16 @@ static int ip6_route_del(struct fib6_config *cfg, if (fn) { for_each_fib6_node_rt_rcu(fn) { if (cfg->fc_flags & RTF_CACHE) { + int rc; + rt_cache = rt6_find_cached_rt(rt, &cfg->fc_dst, &cfg->fc_src); - if (!rt_cache) - continue; - rt = rt_cache; + if (rt_cache) { + rc = ip6_del_cached_rt(rt_cache, cfg); + if (rc != -ESRCH) + return rc; + } + continue; } if (cfg->fc_ifindex && (!rt->fib6_nh.nh_dev ||
@@ -3327,7 +3345,7 @@ static void rt6_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_bu NEIGH_UPDATE_F_ISROUTER)), NDISC_REDIRECT, &ndopts); - nrt = ip6_rt_cache_alloc(rt, &msg->dest, NULL); + nrt = ip6_rt_cache_alloc(rt->from, &msg->dest, NULL); if (!nrt) goto out;
--
2.11.0