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Commit 33bd5ac5 authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

net/ipv6: Revert attempt to simplify route replace and append 



NetworkManager likes to manage linklocal prefix routes and does so with
the NLM_F_APPEND flag, breaking attempts to simplify the IPv6 route
code and by extension enable multipath routes with device only nexthops.

Revert f34436a4 and these followup patches:
6eba08c3 ("ipv6: Only emit append events for appended routes").
ce45bded ("mlxsw: spectrum_router: Align with new route replace logic")
53b562df ("mlxsw: spectrum_router: Allow appending to dev-only routes")

Update the fib_tests cases to reflect the old behavior.

Fixes: f34436a4 ("net/ipv6: Simplify route replace and appending into multipath route")
Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
parent d5a672ac

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

+24 −24
Original line number Diff line number Diff line
@@ -4756,6 +4756,12 @@ static void mlxsw_sp_rt6_destroy(struct mlxsw_sp_rt6 *mlxsw_sp_rt6) 
	kfree(mlxsw_sp_rt6);

}



static bool mlxsw_sp_fib6_rt_can_mp(const struct fib6_info *rt)

{

	/* RTF_CACHE routes are ignored */

	return (rt->fib6_flags & (RTF_GATEWAY | RTF_ADDRCONF)) == RTF_GATEWAY;

}



static struct fib6_info *

mlxsw_sp_fib6_entry_rt(const struct mlxsw_sp_fib6_entry *fib6_entry)

{
@@ -4765,11 +4771,11 @@ mlxsw_sp_fib6_entry_rt(const struct mlxsw_sp_fib6_entry *fib6_entry) 


static struct mlxsw_sp_fib6_entry *

mlxsw_sp_fib6_node_mp_entry_find(const struct mlxsw_sp_fib_node *fib_node,

				 const struct fib6_info *nrt, bool append)

				 const struct fib6_info *nrt, bool replace)

{

	struct mlxsw_sp_fib6_entry *fib6_entry;



	if (!append)

	if (!mlxsw_sp_fib6_rt_can_mp(nrt) || replace)

		return NULL;



	list_for_each_entry(fib6_entry, &fib_node->entry_list, common.list) {
@@ -4784,7 +4790,8 @@ mlxsw_sp_fib6_node_mp_entry_find(const struct mlxsw_sp_fib_node *fib_node, 
			break;

		if (rt->fib6_metric < nrt->fib6_metric)

			continue;

		if (rt->fib6_metric == nrt->fib6_metric)

		if (rt->fib6_metric == nrt->fib6_metric &&

		    mlxsw_sp_fib6_rt_can_mp(rt))

			return fib6_entry;

		if (rt->fib6_metric > nrt->fib6_metric)

			break;
@@ -5163,7 +5170,7 @@ static struct mlxsw_sp_fib6_entry * 
mlxsw_sp_fib6_node_entry_find(const struct mlxsw_sp_fib_node *fib_node,

			      const struct fib6_info *nrt, bool replace)

{

	struct mlxsw_sp_fib6_entry *fib6_entry;

	struct mlxsw_sp_fib6_entry *fib6_entry, *fallback = NULL;



	list_for_each_entry(fib6_entry, &fib_node->entry_list, common.list) {

		struct fib6_info *rt = mlxsw_sp_fib6_entry_rt(fib6_entry);
@@ -5172,13 +5179,18 @@ mlxsw_sp_fib6_node_entry_find(const struct mlxsw_sp_fib_node *fib_node, 
			continue;

		if (rt->fib6_table->tb6_id != nrt->fib6_table->tb6_id)

			break;

		if (replace && rt->fib6_metric == nrt->fib6_metric)

		if (replace && rt->fib6_metric == nrt->fib6_metric) {

			if (mlxsw_sp_fib6_rt_can_mp(rt) ==

			    mlxsw_sp_fib6_rt_can_mp(nrt))

				return fib6_entry;

			if (mlxsw_sp_fib6_rt_can_mp(nrt))

				fallback = fallback ?: fib6_entry;

		}

		if (rt->fib6_metric > nrt->fib6_metric)

			return fib6_entry;

			return fallback ?: fib6_entry;

	}



	return NULL;

	return fallback;

}



static int
@@ -5304,8 +5316,7 @@ static void mlxsw_sp_fib6_entry_replace(struct mlxsw_sp *mlxsw_sp, 
}



static int mlxsw_sp_router_fib6_add(struct mlxsw_sp *mlxsw_sp,

				    struct fib6_info *rt, bool replace,

				    bool append)

				    struct fib6_info *rt, bool replace)

{

	struct mlxsw_sp_fib6_entry *fib6_entry;

	struct mlxsw_sp_fib_node *fib_node;
@@ -5331,7 +5342,7 @@ static int mlxsw_sp_router_fib6_add(struct mlxsw_sp *mlxsw_sp, 
	/* Before creating a new entry, try to append route to an existing

	 * multipath entry.

	 */

	fib6_entry = mlxsw_sp_fib6_node_mp_entry_find(fib_node, rt, append);

	fib6_entry = mlxsw_sp_fib6_node_mp_entry_find(fib_node, rt, replace);

	if (fib6_entry) {

		err = mlxsw_sp_fib6_entry_nexthop_add(mlxsw_sp, fib6_entry, rt);

		if (err)
@@ -5339,14 +5350,6 @@ static int mlxsw_sp_router_fib6_add(struct mlxsw_sp *mlxsw_sp, 
		return 0;

	}



	/* We received an append event, yet did not find any route to

	 * append to.

	 */

	if (WARN_ON(append)) {

		err = -EINVAL;

		goto err_fib6_entry_append;

	}



	fib6_entry = mlxsw_sp_fib6_entry_create(mlxsw_sp, fib_node, rt);

	if (IS_ERR(fib6_entry)) {

		err = PTR_ERR(fib6_entry);
@@ -5364,7 +5367,6 @@ static int mlxsw_sp_router_fib6_add(struct mlxsw_sp *mlxsw_sp, 
err_fib6_node_entry_link:

	mlxsw_sp_fib6_entry_destroy(mlxsw_sp, fib6_entry);

err_fib6_entry_create:

err_fib6_entry_append:

err_fib6_entry_nexthop_add:

	mlxsw_sp_fib_node_put(mlxsw_sp, fib_node);

	return err;
@@ -5715,7 +5717,7 @@ static void mlxsw_sp_router_fib6_event_work(struct work_struct *work) 
	struct mlxsw_sp_fib_event_work *fib_work =

		container_of(work, struct mlxsw_sp_fib_event_work, work);

	struct mlxsw_sp *mlxsw_sp = fib_work->mlxsw_sp;

	bool replace, append;

	bool replace;

	int err;



	rtnl_lock();
@@ -5726,10 +5728,8 @@ static void mlxsw_sp_router_fib6_event_work(struct work_struct *work) 
	case FIB_EVENT_ENTRY_APPEND: /* fall through */

	case FIB_EVENT_ENTRY_ADD:

		replace = fib_work->event == FIB_EVENT_ENTRY_REPLACE;

		append = fib_work->event == FIB_EVENT_ENTRY_APPEND;

		err = mlxsw_sp_router_fib6_add(mlxsw_sp,

					       fib_work->fen6_info.rt, replace,

					       append);

					       fib_work->fen6_info.rt, replace);

		if (err)

			mlxsw_sp_router_fib_abort(mlxsw_sp);

		mlxsw_sp_rt6_release(fib_work->fen6_info.rt);

include/net/ip6_route.h

+6 −0
Original line number Diff line number Diff line
@@ -66,6 +66,12 @@ static inline bool rt6_need_strict(const struct in6_addr *daddr) 
		(IPV6_ADDR_MULTICAST | IPV6_ADDR_LINKLOCAL | IPV6_ADDR_LOOPBACK);

}



static inline bool rt6_qualify_for_ecmp(const struct fib6_info *f6i)

{

	return (f6i->fib6_flags & (RTF_GATEWAY|RTF_ADDRCONF|RTF_DYNAMIC)) ==

	       RTF_GATEWAY;

}



void ip6_route_input(struct sk_buff *skb);

struct dst_entry *ip6_route_input_lookup(struct net *net,

					 struct net_device *dev,

net/ipv6/ip6_fib.c

+86 −70
Original line number Diff line number Diff line
@@ -935,20 +935,19 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
{

	struct fib6_info *leaf = rcu_dereference_protected(fn->leaf,

				    lockdep_is_held(&rt->fib6_table->tb6_lock));

	enum fib_event_type event = FIB_EVENT_ENTRY_ADD;

	struct fib6_info *iter = NULL, *match = NULL;

	struct fib6_info *iter = NULL;

	struct fib6_info __rcu **ins;

	struct fib6_info __rcu **fallback_ins = NULL;

	int replace = (info->nlh &&

		       (info->nlh->nlmsg_flags & NLM_F_REPLACE));

	int append = (info->nlh &&

		       (info->nlh->nlmsg_flags & NLM_F_APPEND));

	int add = (!info->nlh ||

		   (info->nlh->nlmsg_flags & NLM_F_CREATE));

	int found = 0;

	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);

	u16 nlflags = NLM_F_EXCL;

	int err;



	if (append)

	if (info->nlh && (info->nlh->nlmsg_flags & NLM_F_APPEND))

		nlflags |= NLM_F_APPEND;



	ins = &fn->leaf;
@@ -970,9 +969,14 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 


			nlflags &= ~NLM_F_EXCL;

			if (replace) {

				if (rt_can_ecmp == rt6_qualify_for_ecmp(iter)) {

					found++;

					break;

				}

				if (rt_can_ecmp)

					fallback_ins = fallback_ins ?: ins;

				goto next_iter;

			}



			if (rt6_duplicate_nexthop(iter, rt)) {

				if (rt->fib6_nsiblings)
@@ -986,51 +990,71 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
				fib6_metric_set(iter, RTAX_MTU, rt->fib6_pmtu);

				return -EEXIST;

			}



			/* first route that matches */

			if (!match)

				match = iter;

			/* If we have the same destination and the same metric,

			 * but not the same gateway, then the route we try to

			 * add is sibling to this route, increment our counter

			 * of siblings, and later we will add our route to the

			 * list.

			 * Only static routes (which don't have flag

			 * RTF_EXPIRES) are used for ECMPv6.

			 *

			 * To avoid long list, we only had siblings if the

			 * route have a gateway.

			 */

			if (rt_can_ecmp &&

			    rt6_qualify_for_ecmp(iter))

				rt->fib6_nsiblings++;

		}



		if (iter->fib6_metric > rt->fib6_metric)

			break;



next_iter:

		ins = &iter->fib6_next;

	}



	if (fallback_ins && !found) {

		/* No ECMP-able route found, replace first non-ECMP one */

		ins = fallback_ins;

		iter = rcu_dereference_protected(*ins,

				    lockdep_is_held(&rt->fib6_table->tb6_lock));

		found++;

	}



	/* Reset round-robin state, if necessary */

	if (ins == &fn->leaf)

		fn->rr_ptr = NULL;



	/* Link this route to others same route. */

	if (append && match) {

	if (rt->fib6_nsiblings) {

		unsigned int fib6_nsiblings;

		struct fib6_info *sibling, *temp_sibling;



		if (rt->fib6_flags & RTF_REJECT) {

			NL_SET_ERR_MSG(extack,

				       "Can not append a REJECT route");

			return -EINVAL;

		} else if (match->fib6_flags & RTF_REJECT) {

			NL_SET_ERR_MSG(extack,

				       "Can not append to a REJECT route");

			return -EINVAL;

		/* Find the first route that have the same metric */

		sibling = leaf;

		while (sibling) {

			if (sibling->fib6_metric == rt->fib6_metric &&

			    rt6_qualify_for_ecmp(sibling)) {

				list_add_tail(&rt->fib6_siblings,

					      &sibling->fib6_siblings);

				break;

			}

			sibling = rcu_dereference_protected(sibling->fib6_next,

				    lockdep_is_held(&rt->fib6_table->tb6_lock));

		}

		event = FIB_EVENT_ENTRY_APPEND;

		rt->fib6_nsiblings = match->fib6_nsiblings;

		list_add_tail(&rt->fib6_siblings, &match->fib6_siblings);

		match->fib6_nsiblings++;



		/* For each sibling in the list, increment the counter of

		 * siblings. BUG() if counters does not match, list of siblings

		 * is broken!

		 */

		fib6_nsiblings = 0;

		list_for_each_entry_safe(sibling, temp_sibling,

					 &match->fib6_siblings, fib6_siblings) {

					 &rt->fib6_siblings, fib6_siblings) {

			sibling->fib6_nsiblings++;

			BUG_ON(sibling->fib6_nsiblings != match->fib6_nsiblings);

			BUG_ON(sibling->fib6_nsiblings != rt->fib6_nsiblings);

			fib6_nsiblings++;

		}



		rt6_multipath_rebalance(match);

		BUG_ON(fib6_nsiblings != rt->fib6_nsiblings);

		rt6_multipath_rebalance(temp_sibling);

	}



	/*
@@ -1043,8 +1067,9 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
add:

		nlflags |= NLM_F_CREATE;



		err = call_fib6_entry_notifiers(info->nl_net, event, rt,

						extack);

		err = call_fib6_entry_notifiers(info->nl_net,

						FIB_EVENT_ENTRY_ADD,

						rt, extack);

		if (err)

			return err;
@@ -1062,7 +1087,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
		}



	} else {

		struct fib6_info *tmp;

		int nsiblings;



		if (!found) {

			if (add)
@@ -1077,57 +1102,48 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
		if (err)

			return err;



		/* if route being replaced has siblings, set tmp to

		 * last one, otherwise tmp is current route. this is

		 * used to set fib6_next for new route

		 */

		if (iter->fib6_nsiblings)

			tmp = list_last_entry(&iter->fib6_siblings,

					      struct fib6_info,

					      fib6_siblings);

		else

			tmp = iter;



		/* insert new route */

		atomic_inc(&rt->fib6_ref);

		rcu_assign_pointer(rt->fib6_node, fn);

		rt->fib6_next = tmp->fib6_next;

		rt->fib6_next = iter->fib6_next;

		rcu_assign_pointer(*ins, rt);



		if (!info->skip_notify)

			inet6_rt_notify(RTM_NEWROUTE, rt, info, NLM_F_REPLACE);

		if (!(fn->fn_flags & RTN_RTINFO)) {

			info->nl_net->ipv6.rt6_stats->fib_route_nodes++;

			fn->fn_flags |= RTN_RTINFO;

		}

		nsiblings = iter->fib6_nsiblings;

		iter->fib6_node = NULL;

		fib6_purge_rt(iter, fn, info->nl_net);

		if (rcu_access_pointer(fn->rr_ptr) == iter)

			fn->rr_ptr = NULL;

		fib6_info_release(iter);



		/* delete old route */

		rt = iter;



		if (rt->fib6_nsiblings) {

			struct fib6_info *tmp;



		if (nsiblings) {

			/* Replacing an ECMP route, remove all siblings */

			list_for_each_entry_safe(iter, tmp, &rt->fib6_siblings,

						 fib6_siblings) {

			ins = &rt->fib6_next;

			iter = rcu_dereference_protected(*ins,

				    lockdep_is_held(&rt->fib6_table->tb6_lock));

			while (iter) {

				if (iter->fib6_metric > rt->fib6_metric)

					break;

				if (rt6_qualify_for_ecmp(iter)) {

					*ins = iter->fib6_next;

					iter->fib6_node = NULL;

					fib6_purge_rt(iter, fn, info->nl_net);

					if (rcu_access_pointer(fn->rr_ptr) == iter)

						fn->rr_ptr = NULL;

					fib6_info_release(iter);



				rt->fib6_nsiblings--;

					nsiblings--;

					info->nl_net->ipv6.rt6_stats->fib_rt_entries--;

				} else {

					ins = &iter->fib6_next;

				}

				iter = rcu_dereference_protected(*ins,

					lockdep_is_held(&rt->fib6_table->tb6_lock));

			}

			WARN_ON(nsiblings != 0);

		}



		WARN_ON(rt->fib6_nsiblings != 0);



		rt->fib6_node = NULL;

		fib6_purge_rt(rt, fn, info->nl_net);

		if (rcu_access_pointer(fn->rr_ptr) == rt)

			fn->rr_ptr = NULL;

		fib6_info_release(rt);

	}



	return 0;

net/ipv6/route.c

+1 −2
Original line number Diff line number Diff line
@@ -3842,7 +3842,7 @@ static struct fib6_info *rt6_multipath_first_sibling(const struct fib6_info *rt) 
			lockdep_is_held(&rt->fib6_table->tb6_lock));

	while (iter) {

		if (iter->fib6_metric == rt->fib6_metric &&

		    iter->fib6_nsiblings)

		    rt6_qualify_for_ecmp(iter))

			return iter;

		iter = rcu_dereference_protected(iter->fib6_next,

				lockdep_is_held(&rt->fib6_table->tb6_lock));
@@ -4439,7 +4439,6 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, 
		 */

		cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL |

						     NLM_F_REPLACE);

		cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_APPEND;

		nhn++;

	}

tools/testing/selftests/net/fib_tests.sh

+0 −41
Original line number Diff line number Diff line
@@ -740,13 +740,6 @@ ipv6_rt_add() 
	run_cmd "$IP -6 ro add unreachable 2001:db8:104::/64"

	log_test $? 2 "Attempt to add duplicate route - reject route"



	# iproute2 prepend only sets NLM_F_CREATE

	# - adds a new route; does NOT convert existing route to ECMP

	add_route6 "2001:db8:104::/64" "via 2001:db8:101::2"

	run_cmd "$IP -6 ro prepend 2001:db8:104::/64 via 2001:db8:103::2"

	check_route6 "2001:db8:104::/64 via 2001:db8:101::2 dev veth1 metric 1024 2001:db8:104::/64 via 2001:db8:103::2 dev veth3 metric 1024"

	log_test $? 0 "Add new route for existing prefix (w/o NLM_F_EXCL)"



	# route append with same prefix adds a new route

	# - iproute2 sets NLM_F_CREATE | NLM_F_APPEND

	add_route6 "2001:db8:104::/64" "via 2001:db8:101::2"
@@ -754,27 +747,6 @@ ipv6_rt_add() 
	check_route6 "2001:db8:104::/64 metric 1024 nexthop via 2001:db8:101::2 dev veth1 weight 1 nexthop via 2001:db8:103::2 dev veth3 weight 1"

	log_test $? 0 "Append nexthop to existing route - gw"



	add_route6 "2001:db8:104::/64" "via 2001:db8:101::2"

	run_cmd "$IP -6 ro append 2001:db8:104::/64 dev veth3"

	check_route6 "2001:db8:104::/64 metric 1024 nexthop via 2001:db8:101::2 dev veth1 weight 1 nexthop dev veth3 weight 1"

	log_test $? 0 "Append nexthop to existing route - dev only"



	# multipath route can not have a nexthop that is a reject route

	add_route6 "2001:db8:104::/64" "via 2001:db8:101::2"

	run_cmd "$IP -6 ro append unreachable 2001:db8:104::/64"

	log_test $? 2 "Append nexthop to existing route - reject route"



	# reject route can not be converted to multipath route

	run_cmd "$IP -6 ro flush 2001:db8:104::/64"

	run_cmd "$IP -6 ro add unreachable 2001:db8:104::/64"

	run_cmd "$IP -6 ro append 2001:db8:104::/64 via 2001:db8:103::2"

	log_test $? 2 "Append nexthop to existing reject route - gw"



	run_cmd "$IP -6 ro flush 2001:db8:104::/64"

	run_cmd "$IP -6 ro add unreachable 2001:db8:104::/64"

	run_cmd "$IP -6 ro append 2001:db8:104::/64 dev veth3"

	log_test $? 2 "Append nexthop to existing reject route - dev only"



	# insert mpath directly

	add_route6 "2001:db8:104::/64" "nexthop via 2001:db8:101::2 nexthop via 2001:db8:103::2"

	check_route6  "2001:db8:104::/64 metric 1024 nexthop via 2001:db8:101::2 dev veth1 weight 1 nexthop via 2001:db8:103::2 dev veth3 weight 1"
@@ -819,13 +791,6 @@ ipv6_rt_replace_single() 
	check_route6 "2001:db8:104::/64 metric 1024 nexthop via 2001:db8:101::3 dev veth1 weight 1 nexthop via 2001:db8:103::2 dev veth3 weight 1"

	log_test $? 0 "Single path with multipath"



	# single path with reject

	#

	add_initial_route6 "nexthop via 2001:db8:101::2"

	run_cmd "$IP -6 ro replace unreachable 2001:db8:104::/64"

	check_route6 "unreachable 2001:db8:104::/64 dev lo metric 1024"

	log_test $? 0 "Single path with reject route"



	# single path with single path using MULTIPATH attribute

	#

	add_initial_route6 "via 2001:db8:101::2"
@@ -873,12 +838,6 @@ ipv6_rt_replace_mpath() 
	check_route6 "2001:db8:104::/64 via 2001:db8:101::3 dev veth1 metric 1024"

	log_test $? 0 "Multipath with single path via multipath attribute"



	# multipath with reject

	add_initial_route6 "nexthop via 2001:db8:101::2 nexthop via 2001:db8:103::2"

	run_cmd "$IP -6 ro replace unreachable 2001:db8:104::/64"

	check_route6 "unreachable 2001:db8:104::/64 dev lo metric 1024"

	log_test $? 0 "Multipath with reject route"



	# route replace fails - invalid nexthop 1

	add_initial_route6 "nexthop via 2001:db8:101::2 nexthop via 2001:db8:103::2"

	run_cmd "$IP -6 ro replace 2001:db8:104::/64 nexthop via 2001:db8:111::3 nexthop via 2001:db8:103::3"