Commit 23fb93a4 authored by David Ahern's avatar David Ahern Committed by David S. Miller
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net/ipv6: Cleanup exception and cache route handling 



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: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent acb54e3c

include/net/ip6_route.h

+0 −1
Original line number Diff line number Diff line
@@ -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);

net/ipv6/ip6_fib.c

+1 −15
Original line number Diff line number Diff line
@@ -1074,7 +1074,7 @@ add: 
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

	 */

net/ipv6/route.c

+80 −62
Original line number Diff line number Diff line
@@ -1013,7 +1013,7 @@ 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);

	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) {
@@ -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;
@@ -1106,37 +1107,37 @@ 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 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 @@ redo_rt6_select: 
		}

	}



	/*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 @@ redo_rt6_select: 
		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 @@ redo_rt6_select: 


		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 @@ uncached_rt_out: 


		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 @@ restart: 
			if (rt_cache &&

			    ipv6_addr_equal(&rdfl->gateway,

					    &rt_cache->rt6i_gateway)) {

				rt = rt_cache;

				ret = rt_cache;

				break;

			}

			continue;
@@ -2469,7 +2463,7 @@ restart: 
	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 @@ restart: 
	}



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 @@ out_put: 
	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)

				if (rt_cache) {

					rc = ip6_del_cached_rt(rt_cache, cfg);

					if (rc != -ESRCH)

						return rc;

				}

				continue;

				rt = rt_cache;

			}

			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;

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