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2024-10-22 8ac6c7a54ed1b98d142dce24b11c6de6a1e239a5 
 kernel/net/ipv6/ip6_fib.c
....@@ -1,14 +1,10 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  *	Linux INET6 implementation
34  *	Forwarding Information Database
45  *
56  *	Authors:
67  *	Pedro Roque		<roque@di.fc.ul.pt>
7
- *
8
- *	This program is free software; you can redistribute it and/or
9
- *      modify it under the terms of the GNU General Public License
10
- *      as published by the Free Software Foundation; either version
11
- *      2 of the License, or (at your option) any later version.
128  *
139  *	Changes:
1410  *	Yuji SEKIYA @USAGI:	Support default route on router node;
....@@ -29,6 +25,7 @@
2925 #include <linux/list.h>
3026 #include <linux/slab.h>
3127 
28
+#include <net/ip.h>
3229 #include <net/ipv6.h>
3330 #include <net/ndisc.h>
3431 #include <net/addrconf.h>
....@@ -46,6 +43,7 @@
4643 	int (*func)(struct fib6_info *, void *arg);
4744 	int sernum;
4845 	void *arg;
46
+	bool skip_notify;
4947 };
5048 
5149 #ifdef CONFIG_IPV6_SUBTREES
....@@ -145,24 +143,21 @@
145143 	       addr[fn_bit >> 5];
146144 }
147145 
148
-struct fib6_info *fib6_info_alloc(gfp_t gfp_flags)
146
+struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh)
149147 {
150148 	struct fib6_info *f6i;
149
+	size_t sz = sizeof(*f6i);
151150 
152
-	f6i = kzalloc(sizeof(*f6i), gfp_flags);
151
+	if (with_fib6_nh)
152
+		sz += sizeof(struct fib6_nh);
153
+
154
+	f6i = kzalloc(sz, gfp_flags);
153155 	if (!f6i)
154156 		return NULL;
155157 
156
-	f6i->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
157
-	if (!f6i->rt6i_pcpu) {
158
-		kfree(f6i);
159
-		return NULL;
160
-	}
161
-
158
+	/* fib6_siblings is a union with nh_list, so this initializes both */
162159 	INIT_LIST_HEAD(&f6i->fib6_siblings);
163
-	f6i->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
164
-
165
-	atomic_inc(&f6i->fib6_ref);
160
+	refcount_set(&f6i->fib6_ref, 1);
166161 
167162 	return f6i;
168163 }
....@@ -170,45 +165,15 @@
170165 void fib6_info_destroy_rcu(struct rcu_head *head)
171166 {
172167 	struct fib6_info *f6i = container_of(head, struct fib6_info, rcu);
173
-	struct rt6_exception_bucket *bucket;
174
-	struct dst_metrics *m;
175168 
176169 	WARN_ON(f6i->fib6_node);
177170 
178
-	bucket = rcu_dereference_protected(f6i->rt6i_exception_bucket, 1);
179
-	if (bucket) {
180
-		f6i->rt6i_exception_bucket = NULL;
181
-		kfree(bucket);
182
-	}
171
+	if (f6i->nh)
172
+		nexthop_put(f6i->nh);
173
+	else
174
+		fib6_nh_release(f6i->fib6_nh);
183175 
184
-	if (f6i->rt6i_pcpu) {
185
-		int cpu;
186
-
187
-		for_each_possible_cpu(cpu) {
188
-			struct rt6_info **ppcpu_rt;
189
-			struct rt6_info *pcpu_rt;
190
-
191
-			ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
192
-			pcpu_rt = *ppcpu_rt;
193
-			if (pcpu_rt) {
194
-				dst_dev_put(&pcpu_rt->dst);
195
-				dst_release(&pcpu_rt->dst);
196
-				*ppcpu_rt = NULL;
197
-			}
198
-		}
199
-
200
-		free_percpu(f6i->rt6i_pcpu);
201
-	}
202
-
203
-	lwtstate_put(f6i->fib6_nh.nh_lwtstate);
204
-
205
-	if (f6i->fib6_nh.nh_dev)
206
-		dev_put(f6i->fib6_nh.nh_dev);
207
-
208
-	m = f6i->fib6_metrics;
209
-	if (m != &dst_default_metrics && refcount_dec_and_test(&m->refcnt))
210
-		kfree(m);
211
-
176
+	ip_fib_metrics_put(f6i->fib6_metrics);
212177 	kfree(f6i);
213178 }
214179 EXPORT_SYMBOL_GPL(fib6_info_destroy_rcu);
....@@ -349,21 +314,24 @@
349314 {
350315 	struct rt6_info *rt;
351316 
352
-	rt = lookup(net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
317
+	rt = pol_lookup_func(lookup,
318
+			net, net->ipv6.fib6_main_tbl, fl6, skb, flags);
353319 	if (rt->dst.error == -EAGAIN) {
354
-		ip6_rt_put(rt);
320
+		ip6_rt_put_flags(rt, flags);
355321 		rt = net->ipv6.ip6_null_entry;
356
-		dst_hold(&rt->dst);
322
+		if (!(flags & RT6_LOOKUP_F_DST_NOREF))
323
+			dst_hold(&rt->dst);
357324 	}
358325 
359326 	return &rt->dst;
360327 }
361328 
362329 /* called with rcu lock held; no reference taken on fib6_info */
363
-struct fib6_info *fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
364
-			      int flags)
330
+int fib6_lookup(struct net *net, int oif, struct flowi6 *fl6,
331
+		struct fib6_result *res, int flags)
365332 {
366
-	return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6, flags);
333
+	return fib6_table_lookup(net, net->ipv6.fib6_main_tbl, oif, fl6,
334
+				 res, flags);
367335 }
368336 
369337 static void __net_init fib6_tables_init(struct net *net)
....@@ -390,21 +358,38 @@
390358 	return fib_seq;
391359 }
392360 
393
-static int call_fib6_entry_notifier(struct notifier_block *nb, struct net *net,
361
+static int call_fib6_entry_notifier(struct notifier_block *nb,
394362 				    enum fib_event_type event_type,
395
-				    struct fib6_info *rt)
363
+				    struct fib6_info *rt,
364
+				    struct netlink_ext_ack *extack)
396365 {
397366 	struct fib6_entry_notifier_info info = {
367
+		.info.extack = extack,
398368 		.rt = rt,
399369 	};
400370 
401
-	return call_fib6_notifier(nb, net, event_type, &info.info);
371
+	return call_fib6_notifier(nb, event_type, &info.info);
402372 }
403373 
404
-static int call_fib6_entry_notifiers(struct net *net,
405
-				     enum fib_event_type event_type,
406
-				     struct fib6_info *rt,
407
-				     struct netlink_ext_ack *extack)
374
+static int call_fib6_multipath_entry_notifier(struct notifier_block *nb,
375
+					      enum fib_event_type event_type,
376
+					      struct fib6_info *rt,
377
+					      unsigned int nsiblings,
378
+					      struct netlink_ext_ack *extack)
379
+{
380
+	struct fib6_entry_notifier_info info = {
381
+		.info.extack = extack,
382
+		.rt = rt,
383
+		.nsiblings = nsiblings,
384
+	};
385
+
386
+	return call_fib6_notifier(nb, event_type, &info.info);
387
+}
388
+
389
+int call_fib6_entry_notifiers(struct net *net,
390
+			      enum fib_event_type event_type,
391
+			      struct fib6_info *rt,
392
+			      struct netlink_ext_ack *extack)
408393 {
409394 	struct fib6_entry_notifier_info info = {
410395 		.info.extack = extack,
....@@ -415,43 +400,88 @@
415400 	return call_fib6_notifiers(net, event_type, &info.info);
416401 }
417402 
403
+int call_fib6_multipath_entry_notifiers(struct net *net,
404
+					enum fib_event_type event_type,
405
+					struct fib6_info *rt,
406
+					unsigned int nsiblings,
407
+					struct netlink_ext_ack *extack)
408
+{
409
+	struct fib6_entry_notifier_info info = {
410
+		.info.extack = extack,
411
+		.rt = rt,
412
+		.nsiblings = nsiblings,
413
+	};
414
+
415
+	rt->fib6_table->fib_seq++;
416
+	return call_fib6_notifiers(net, event_type, &info.info);
417
+}
418
+
419
+int call_fib6_entry_notifiers_replace(struct net *net, struct fib6_info *rt)
420
+{
421
+	struct fib6_entry_notifier_info info = {
422
+		.rt = rt,
423
+		.nsiblings = rt->fib6_nsiblings,
424
+	};
425
+
426
+	rt->fib6_table->fib_seq++;
427
+	return call_fib6_notifiers(net, FIB_EVENT_ENTRY_REPLACE, &info.info);
428
+}
429
+
418430 struct fib6_dump_arg {
419431 	struct net *net;
420432 	struct notifier_block *nb;
433
+	struct netlink_ext_ack *extack;
421434 };
422435 
423
-static void fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
436
+static int fib6_rt_dump(struct fib6_info *rt, struct fib6_dump_arg *arg)
424437 {
425
-	if (rt == arg->net->ipv6.fib6_null_entry)
426
-		return;
427
-	call_fib6_entry_notifier(arg->nb, arg->net, FIB_EVENT_ENTRY_ADD, rt);
438
+	enum fib_event_type fib_event = FIB_EVENT_ENTRY_REPLACE;
439
+	int err;
440
+
441
+	if (!rt || rt == arg->net->ipv6.fib6_null_entry)
442
+		return 0;
443
+
444
+	if (rt->fib6_nsiblings)
445
+		err = call_fib6_multipath_entry_notifier(arg->nb, fib_event,
446
+							 rt,
447
+							 rt->fib6_nsiblings,
448
+							 arg->extack);
449
+	else
450
+		err = call_fib6_entry_notifier(arg->nb, fib_event, rt,
451
+					       arg->extack);
452
+
453
+	return err;
428454 }
429455 
430456 static int fib6_node_dump(struct fib6_walker *w)
431457 {
432
-	struct fib6_info *rt;
458
+	int err;
433459 
434
-	for_each_fib6_walker_rt(w)
435
-		fib6_rt_dump(rt, w->args);
460
+	err = fib6_rt_dump(w->leaf, w->args);
436461 	w->leaf = NULL;
437
-	return 0;
462
+	return err;
438463 }
439464 
440
-static void fib6_table_dump(struct net *net, struct fib6_table *tb,
441
-			    struct fib6_walker *w)
465
+static int fib6_table_dump(struct net *net, struct fib6_table *tb,
466
+			   struct fib6_walker *w)
442467 {
468
+	int err;
469
+
443470 	w->root = &tb->tb6_root;
444471 	spin_lock_bh(&tb->tb6_lock);
445
-	fib6_walk(net, w);
472
+	err = fib6_walk(net, w);
446473 	spin_unlock_bh(&tb->tb6_lock);
474
+	return err;
447475 }
448476 
449477 /* Called with rcu_read_lock() */
450
-int fib6_tables_dump(struct net *net, struct notifier_block *nb)
478
+int fib6_tables_dump(struct net *net, struct notifier_block *nb,
479
+		     struct netlink_ext_ack *extack)
451480 {
452481 	struct fib6_dump_arg arg;
453482 	struct fib6_walker *w;
454483 	unsigned int h;
484
+	int err = 0;
455485 
456486 	w = kzalloc(sizeof(*w), GFP_ATOMIC);
457487 	if (!w)
....@@ -460,19 +490,24 @@
460490 	w->func = fib6_node_dump;
461491 	arg.net = net;
462492 	arg.nb = nb;
493
+	arg.extack = extack;
463494 	w->args = &arg;
464495 
465496 	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
466497 		struct hlist_head *head = &net->ipv6.fib_table_hash[h];
467498 		struct fib6_table *tb;
468499 
469
-		hlist_for_each_entry_rcu(tb, head, tb6_hlist)
470
-			fib6_table_dump(net, tb, w);
500
+		hlist_for_each_entry_rcu(tb, head, tb6_hlist) {
501
+			err = fib6_table_dump(net, tb, w);
502
+			if (err < 0)
503
+				goto out;
504
+		}
471505 	}
472506 
507
+out:
473508 	kfree(w);
474509 
475
-	return 0;
510
+	return err;
476511 }
477512 
478513 static int fib6_dump_node(struct fib6_walker *w)
....@@ -481,12 +516,19 @@
481516 	struct fib6_info *rt;
482517 
483518 	for_each_fib6_walker_rt(w) {
484
-		res = rt6_dump_route(rt, w->args);
485
-		if (res < 0) {
519
+		res = rt6_dump_route(rt, w->args, w->skip_in_node);
520
+		if (res >= 0) {
486521 			/* Frame is full, suspend walking */
487522 			w->leaf = rt;
523
+
524
+			/* We'll restart from this node, so if some routes were
525
+			 * already dumped, skip them next time.
526
+			 */
527
+			w->skip_in_node += res;
528
+
488529 			return 1;
489530 		}
531
+		w->skip_in_node = 0;
490532 
491533 		/* Multipath routes are dumped in one route with the
492534 		 * RTA_MULTIPATH attribute. Jump 'rt' to point to the
....@@ -538,6 +580,7 @@
538580 	if (cb->args[4] == 0) {
539581 		w->count = 0;
540582 		w->skip = 0;
583
+		w->skip_in_node = 0;
541584 
542585 		spin_lock_bh(&table->tb6_lock);
543586 		res = fib6_walk(net, w);
....@@ -554,6 +597,7 @@
554597 			w->state = FWS_INIT;
555598 			w->node = w->root;
556599 			w->skip = w->count;
600
+			w->skip_in_node = 0;
557601 		} else
558602 			w->skip = 0;
559603 
....@@ -571,17 +615,29 @@
571615 
572616 static int inet6_dump_fib(struct sk_buff *skb, struct netlink_callback *cb)
573617 {
618
+	struct rt6_rtnl_dump_arg arg = { .filter.dump_exceptions = true,
619
+					 .filter.dump_routes = true };
620
+	const struct nlmsghdr *nlh = cb->nlh;
574621 	struct net *net = sock_net(skb->sk);
575622 	unsigned int h, s_h;
576623 	unsigned int e = 0, s_e;
577
-	struct rt6_rtnl_dump_arg arg;
578624 	struct fib6_walker *w;
579625 	struct fib6_table *tb;
580626 	struct hlist_head *head;
581627 	int res = 0;
582628 
583
-	s_h = cb->args[0];
584
-	s_e = cb->args[1];
629
+	if (cb->strict_check) {
630
+		int err;
631
+
632
+		err = ip_valid_fib_dump_req(net, nlh, &arg.filter, cb);
633
+		if (err < 0)
634
+			return err;
635
+	} else if (nlmsg_len(nlh) >= sizeof(struct rtmsg)) {
636
+		struct rtmsg *rtm = nlmsg_data(nlh);
637
+
638
+		if (rtm->rtm_flags & RTM_F_PREFIX)
639
+			arg.filter.flags = RTM_F_PREFIX;
640
+	}
585641 
586642 	w = (void *)cb->args[2];
587643 	if (!w) {
....@@ -607,6 +663,27 @@
607663 	arg.net = net;
608664 	w->args = &arg;
609665 
666
+	if (arg.filter.table_id) {
667
+		tb = fib6_get_table(net, arg.filter.table_id);
668
+		if (!tb) {
669
+			if (rtnl_msg_family(cb->nlh) != PF_INET6)
670
+				goto out;
671
+
672
+			NL_SET_ERR_MSG_MOD(cb->extack, "FIB table does not exist");
673
+			return -ENOENT;
674
+		}
675
+
676
+		if (!cb->args[0]) {
677
+			res = fib6_dump_table(tb, skb, cb);
678
+			if (!res)
679
+				cb->args[0] = 1;
680
+		}
681
+		goto out;
682
+	}
683
+
684
+	s_h = cb->args[0];
685
+	s_e = cb->args[1];
686
+
610687 	rcu_read_lock();
611688 	for (h = s_h; h < FIB6_TABLE_HASHSZ; h++, s_e = 0) {
612689 		e = 0;
....@@ -616,16 +693,16 @@
616693 				goto next;
617694 			res = fib6_dump_table(tb, skb, cb);
618695 			if (res != 0)
619
-				goto out;
696
+				goto out_unlock;
620697 next:
621698 			e++;
622699 		}
623700 	}
624
-out:
701
+out_unlock:
625702 	rcu_read_unlock();
626703 	cb->args[1] = e;
627704 	cb->args[0] = h;
628
-
705
+out:
629706 	res = res < 0 ? res : skb->len;
630707 	if (res <= 0)
631708 		fib6_dump_end(cb);
....@@ -820,8 +897,8 @@
820897 
821898 		RCU_INIT_POINTER(in->parent, pn);
822899 		in->leaf = fn->leaf;
823
-		atomic_inc(&rcu_dereference_protected(in->leaf,
824
-				lockdep_is_held(&table->tb6_lock))->fib6_ref);
900
+		fib6_info_hold(rcu_dereference_protected(in->leaf,
901
+				lockdep_is_held(&table->tb6_lock)));
825902 
826903 		/* update parent pointer */
827904 		if (dir)
....@@ -873,16 +950,14 @@
873950 	return ln;
874951 }
875952 
876
-static void fib6_drop_pcpu_from(struct fib6_info *f6i,
877
-				const struct fib6_table *table)
953
+static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
954
+				  const struct fib6_info *match,
955
+				  const struct fib6_table *table)
878956 {
879957 	int cpu;
880958 
881
-	/* Make sure rt6_make_pcpu_route() wont add other percpu routes
882
-	 * while we are cleaning them here.
883
-	 */
884
-	f6i->fib6_destroying = 1;
885
-	mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
959
+	if (!fib6_nh->rt6i_pcpu)
960
+		return;
886961 
887962 	/* release the reference to this fib entry from
888963 	 * all of its cached pcpu routes
....@@ -891,14 +966,58 @@
891966 		struct rt6_info **ppcpu_rt;
892967 		struct rt6_info *pcpu_rt;
893968 
894
-		ppcpu_rt = per_cpu_ptr(f6i->rt6i_pcpu, cpu);
969
+		ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
895970 		pcpu_rt = *ppcpu_rt;
896
-		if (pcpu_rt) {
971
+
972
+		/* only dropping the 'from' reference if the cached route
973
+		 * is using 'match'. The cached pcpu_rt->from only changes
974
+		 * from a fib6_info to NULL (ip6_dst_destroy); it can never
975
+		 * change from one fib6_info reference to another
976
+		 */
977
+		if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
897978 			struct fib6_info *from;
898979 
899980 			from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
900981 			fib6_info_release(from);
901982 		}
983
+	}
984
+}
985
+
986
+struct fib6_nh_pcpu_arg {
987
+	struct fib6_info	*from;
988
+	const struct fib6_table *table;
989
+};
990
+
991
+static int fib6_nh_drop_pcpu_from(struct fib6_nh *nh, void *_arg)
992
+{
993
+	struct fib6_nh_pcpu_arg *arg = _arg;
994
+
995
+	__fib6_drop_pcpu_from(nh, arg->from, arg->table);
996
+	return 0;
997
+}
998
+
999
+static void fib6_drop_pcpu_from(struct fib6_info *f6i,
1000
+				const struct fib6_table *table)
1001
+{
1002
+	/* Make sure rt6_make_pcpu_route() wont add other percpu routes
1003
+	 * while we are cleaning them here.
1004
+	 */
1005
+	f6i->fib6_destroying = 1;
1006
+	mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
1007
+
1008
+	if (f6i->nh) {
1009
+		struct fib6_nh_pcpu_arg arg = {
1010
+			.from = f6i,
1011
+			.table = table
1012
+		};
1013
+
1014
+		nexthop_for_each_fib6_nh(f6i->nh, fib6_nh_drop_pcpu_from,
1015
+					 &arg);
1016
+	} else {
1017
+		struct fib6_nh *fib6_nh;
1018
+
1019
+		fib6_nh = f6i->fib6_nh;
1020
+		__fib6_drop_pcpu_from(fib6_nh, f6i, table);
9021021 	}
9031022 }
9041023 
....@@ -909,10 +1028,12 @@
9091028 
9101029 	/* Flush all cached dst in exception table */
9111030 	rt6_flush_exceptions(rt);
912
-	if (rt->rt6i_pcpu)
913
-		fib6_drop_pcpu_from(rt, table);
1031
+	fib6_drop_pcpu_from(rt, table);
9141032 
915
-	if (atomic_read(&rt->fib6_ref) != 1) {
1033
+	if (rt->nh && !list_empty(&rt->nh_list))
1034
+		list_del_init(&rt->nh_list);
1035
+
1036
+	if (refcount_read(&rt->fib6_ref) != 1) {
9161037 		/* This route is used as dummy address holder in some split
9171038 		 * nodes. It is not leaked, but it still holds other resources,
9181039 		 * which must be released in time. So, scan ascendant nodes
....@@ -925,7 +1046,7 @@
9251046 			struct fib6_info *new_leaf;
9261047 			if (!(fn->fn_flags & RTN_RTINFO) && leaf == rt) {
9271048 				new_leaf = fib6_find_prefix(net, table, fn);
928
-				atomic_inc(&new_leaf->fib6_ref);
1049
+				fib6_info_hold(new_leaf);
9291050 
9301051 				rcu_assign_pointer(fn->leaf, new_leaf);
9311052 				fib6_info_release(rt);
....@@ -955,6 +1076,7 @@
9551076 		   (info->nlh->nlmsg_flags & NLM_F_CREATE));
9561077 	int found = 0;
9571078 	bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
1079
+	bool notify_sibling_rt = false;
9581080 	u16 nlflags = NLM_F_EXCL;
9591081 	int err;
9601082 
....@@ -1047,6 +1169,7 @@
10471169 
10481170 		/* Find the first route that have the same metric */
10491171 		sibling = leaf;
1172
+		notify_sibling_rt = true;
10501173 		while (sibling) {
10511174 			if (sibling->fib6_metric == rt->fib6_metric &&
10521175 			    rt6_qualify_for_ecmp(sibling)) {
....@@ -1056,6 +1179,7 @@
10561179 			}
10571180 			sibling = rcu_dereference_protected(sibling->fib6_next,
10581181 				    lockdep_is_held(&rt->fib6_table->tb6_lock));
1182
+			notify_sibling_rt = false;
10591183 		}
10601184 		/* For each sibling in the list, increment the counter of
10611185 		 * siblings. BUG() if counters does not match, list of siblings
....@@ -1082,30 +1206,43 @@
10821206 add:
10831207 		nlflags |= NLM_F_CREATE;
10841208 
1085
-		err = call_fib6_entry_notifiers(info->nl_net,
1086
-						FIB_EVENT_ENTRY_ADD,
1087
-						rt, extack);
1088
-		if (err) {
1089
-			struct fib6_info *sibling, *next_sibling;
1209
+		/* The route should only be notified if it is the first
1210
+		 * route in the node or if it is added as a sibling
1211
+		 * route to the first route in the node.
1212
+		 */
1213
+		if (!info->skip_notify_kernel &&
1214
+		    (notify_sibling_rt || ins == &fn->leaf)) {
1215
+			enum fib_event_type fib_event;
10901216 
1091
-			/* If the route has siblings, then it first
1092
-			 * needs to be unlinked from them.
1093
-			 */
1094
-			if (!rt->fib6_nsiblings)
1217
+			if (notify_sibling_rt)
1218
+				fib_event = FIB_EVENT_ENTRY_APPEND;
1219
+			else
1220
+				fib_event = FIB_EVENT_ENTRY_REPLACE;
1221
+			err = call_fib6_entry_notifiers(info->nl_net,
1222
+							fib_event, rt,
1223
+							extack);
1224
+			if (err) {
1225
+				struct fib6_info *sibling, *next_sibling;
1226
+
1227
+				/* If the route has siblings, then it first
1228
+				 * needs to be unlinked from them.
1229
+				 */
1230
+				if (!rt->fib6_nsiblings)
1231
+					return err;
1232
+
1233
+				list_for_each_entry_safe(sibling, next_sibling,
1234
+							 &rt->fib6_siblings,
1235
+							 fib6_siblings)
1236
+					sibling->fib6_nsiblings--;
1237
+				rt->fib6_nsiblings = 0;
1238
+				list_del_init(&rt->fib6_siblings);
1239
+				rt6_multipath_rebalance(next_sibling);
10951240 				return err;
1096
-
1097
-			list_for_each_entry_safe(sibling, next_sibling,
1098
-						 &rt->fib6_siblings,
1099
-						 fib6_siblings)
1100
-				sibling->fib6_nsiblings--;
1101
-			rt->fib6_nsiblings = 0;
1102
-			list_del_init(&rt->fib6_siblings);
1103
-			rt6_multipath_rebalance(next_sibling);
1104
-			return err;
1241
+			}
11051242 		}
11061243 
11071244 		rcu_assign_pointer(rt->fib6_next, iter);
1108
-		atomic_inc(&rt->fib6_ref);
1245
+		fib6_info_hold(rt);
11091246 		rcu_assign_pointer(rt->fib6_node, fn);
11101247 		rcu_assign_pointer(*ins, rt);
11111248 		if (!info->skip_notify)
....@@ -1127,13 +1264,15 @@
11271264 			return -ENOENT;
11281265 		}
11291266 
1130
-		err = call_fib6_entry_notifiers(info->nl_net,
1131
-						FIB_EVENT_ENTRY_REPLACE,
1132
-						rt, extack);
1133
-		if (err)
1134
-			return err;
1267
+		if (!info->skip_notify_kernel && ins == &fn->leaf) {
1268
+			err = call_fib6_entry_notifiers(info->nl_net,
1269
+							FIB_EVENT_ENTRY_REPLACE,
1270
+							rt, extack);
1271
+			if (err)
1272
+				return err;
1273
+		}
11351274 
1136
-		atomic_inc(&rt->fib6_ref);
1275
+		fib6_info_hold(rt);
11371276 		rcu_assign_pointer(rt->fib6_node, fn);
11381277 		rt->fib6_next = iter->fib6_next;
11391278 		rcu_assign_pointer(*ins, rt);
....@@ -1215,6 +1354,14 @@
12151354 	__fib6_update_sernum_upto_root(rt, fib6_new_sernum(net));
12161355 }
12171356 
1357
+/* allow ipv4 to update sernum via ipv6_stub */
1358
+void fib6_update_sernum_stub(struct net *net, struct fib6_info *f6i)
1359
+{
1360
+	spin_lock_bh(&f6i->fib6_table->tb6_lock);
1361
+	fib6_update_sernum_upto_root(net, f6i);
1362
+	spin_unlock_bh(&f6i->fib6_table->tb6_lock);
1363
+}
1364
+
12181365 /*
12191366  *	Add routing information to the routing tree.
12201367  *	<destination addr>/<source addr>
....@@ -1230,7 +1377,6 @@
12301377 	int err = -ENOMEM;
12311378 	int allow_create = 1;
12321379 	int replace_required = 0;
1233
-	int sernum = fib6_new_sernum(info->nl_net);
12341380 
12351381 	if (info->nlh) {
12361382 		if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))
....@@ -1275,7 +1421,7 @@
12751421 			if (!sfn)
12761422 				goto failure;
12771423 
1278
-			atomic_inc(&info->nl_net->ipv6.fib6_null_entry->fib6_ref);
1424
+			fib6_info_hold(info->nl_net->ipv6.fib6_null_entry);
12791425 			rcu_assign_pointer(sfn->leaf,
12801426 					   info->nl_net->ipv6.fib6_null_entry);
12811427 			sfn->fn_flags = RTN_ROOT;
....@@ -1318,7 +1464,7 @@
13181464 				rcu_assign_pointer(fn->leaf,
13191465 					    info->nl_net->ipv6.fib6_null_entry);
13201466 			} else {
1321
-				atomic_inc(&rt->fib6_ref);
1467
+				fib6_info_hold(rt);
13221468 				rcu_assign_pointer(fn->leaf, rt);
13231469 			}
13241470 		}
....@@ -1328,7 +1474,9 @@
13281474 
13291475 	err = fib6_add_rt2node(fn, rt, info, extack);
13301476 	if (!err) {
1331
-		__fib6_update_sernum_upto_root(rt, sernum);
1477
+		if (rt->nh)
1478
+			list_add(&rt->nh_list, &rt->nh->f6i_list);
1479
+		__fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));
13321480 		fib6_start_gc(info->nl_net, rt);
13331481 	}
13341482 
....@@ -1364,6 +1512,8 @@
13641512 		}
13651513 #endif
13661514 		goto failure;
1515
+	} else if (fib6_requires_src(rt)) {
1516
+		fib6_routes_require_src_inc(info->nl_net);
13671517 	}
13681518 	return err;
13691519 
....@@ -1664,10 +1814,14 @@
16641814 
16651815 		children = 0;
16661816 		child = NULL;
1667
-		if (fn_r)
1668
-			child = fn_r, children |= 1;
1669
-		if (fn_l)
1670
-			child = fn_l, children |= 2;
1817
+		if (fn_r) {
1818
+			child = fn_r;
1819
+			children |= 1;
1820
+		}
1821
+		if (fn_l) {
1822
+			child = fn_l;
1823
+			children |= 2;
1824
+		}
16711825 
16721826 		if (children == 3 || FIB6_SUBTREE(fn)
16731827 #ifdef CONFIG_IPV6_SUBTREES
....@@ -1746,12 +1900,28 @@
17461900 static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
17471901 			   struct fib6_info __rcu **rtp, struct nl_info *info)
17481902 {
1903
+	struct fib6_info *leaf, *replace_rt = NULL;
17491904 	struct fib6_walker *w;
17501905 	struct fib6_info *rt = rcu_dereference_protected(*rtp,
17511906 				    lockdep_is_held(&table->tb6_lock));
17521907 	struct net *net = info->nl_net;
1908
+	bool notify_del = false;
17531909 
17541910 	RT6_TRACE("fib6_del_route\n");
1911
+
1912
+	/* If the deleted route is the first in the node and it is not part of
1913
+	 * a multipath route, then we need to replace it with the next route
1914
+	 * in the node, if exists.
1915
+	 */
1916
+	leaf = rcu_dereference_protected(fn->leaf,
1917
+					 lockdep_is_held(&table->tb6_lock));
1918
+	if (leaf == rt && !rt->fib6_nsiblings) {
1919
+		if (rcu_access_pointer(rt->fib6_next))
1920
+			replace_rt = rcu_dereference_protected(rt->fib6_next,
1921
+					    lockdep_is_held(&table->tb6_lock));
1922
+		else
1923
+			notify_del = true;
1924
+	}
17551925 
17561926 	/* Unlink it */
17571927 	*rtp = rt->fib6_next;
....@@ -1767,6 +1937,14 @@
17671937 	if (rt->fib6_nsiblings) {
17681938 		struct fib6_info *sibling, *next_sibling;
17691939 
1940
+		/* The route is deleted from a multipath route. If this
1941
+		 * multipath route is the first route in the node, then we need
1942
+		 * to emit a delete notification. Otherwise, we need to skip
1943
+		 * the notification.
1944
+		 */
1945
+		if (rt->fib6_metric == leaf->fib6_metric &&
1946
+		    rt6_qualify_for_ecmp(leaf))
1947
+			notify_del = true;
17701948 		list_for_each_entry_safe(sibling, next_sibling,
17711949 					 &rt->fib6_siblings, fib6_siblings)
17721950 			sibling->fib6_nsiblings--;
....@@ -1802,9 +1980,16 @@
18021980 
18031981 	fib6_purge_rt(rt, fn, net);
18041982 
1805
-	call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, rt, NULL);
1983
+	if (!info->skip_notify_kernel) {
1984
+		if (notify_del)
1985
+			call_fib6_entry_notifiers(net, FIB_EVENT_ENTRY_DEL,
1986
+						  rt, NULL);
1987
+		else if (replace_rt)
1988
+			call_fib6_entry_notifiers_replace(net, replace_rt);
1989
+	}
18061990 	if (!info->skip_notify)
18071991 		inet6_rt_notify(RTM_DELROUTE, rt, info, 0);
1992
+
18081993 	fib6_info_release(rt);
18091994 }
18101995 
....@@ -1836,6 +2021,8 @@
18362021 		struct fib6_info *cur = rcu_dereference_protected(*rtp,
18372022 					lockdep_is_held(&table->tb6_lock));
18382023 		if (rt == cur) {
2024
+			if (fib6_requires_src(cur))
2025
+				fib6_routes_require_src_dec(info->nl_net);
18392026 			fib6_del_route(table, fn, rtp, info);
18402027 			return 0;
18412028 		}
....@@ -1890,8 +2077,8 @@
18902077 				continue;
18912078 			}
18922079 			w->state = FWS_L;
2080
+			fallthrough;
18932081 #endif
1894
-			/* fall through */
18952082 		case FWS_L:
18962083 			left = rcu_dereference_protected(fn->left, 1);
18972084 			if (left) {
....@@ -1900,7 +2087,7 @@
19002087 				continue;
19012088 			}
19022089 			w->state = FWS_R;
1903
-			/* fall through */
2090
+			fallthrough;
19042091 		case FWS_R:
19052092 			right = rcu_dereference_protected(fn->right, 1);
19062093 			if (right) {
....@@ -1910,7 +2097,7 @@
19102097 			}
19112098 			w->state = FWS_C;
19122099 			w->leaf = rcu_dereference_protected(fn->leaf, 1);
1913
-			/* fall through */
2100
+			fallthrough;
19142101 		case FWS_C:
19152102 			if (w->leaf && fn->fn_flags & RTN_RTINFO) {
19162103 				int err;
....@@ -1929,7 +2116,7 @@
19292116 			}
19302117 skip:
19312118 			w->state = FWS_U;
1932
-			/* fall through */
2119
+			fallthrough;
19332120 		case FWS_U:
19342121 			if (fn == w->root)
19352122 				return 0;
....@@ -1981,6 +2168,7 @@
19812168 	struct fib6_cleaner *c = container_of(w, struct fib6_cleaner, w);
19822169 	struct nl_info info = {
19832170 		.nl_net = c->net,
2171
+		.skip_notify = c->skip_notify,
19842172 	};
19852173 
19862174 	if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
....@@ -2032,7 +2220,7 @@
20322220 
20332221 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
20342222 			    int (*func)(struct fib6_info *, void *arg),
2035
-			    int sernum, void *arg)
2223
+			    int sernum, void *arg, bool skip_notify)
20362224 {
20372225 	struct fib6_cleaner c;
20382226 
....@@ -2040,17 +2228,19 @@
20402228 	c.w.func = fib6_clean_node;
20412229 	c.w.count = 0;
20422230 	c.w.skip = 0;
2231
+	c.w.skip_in_node = 0;
20432232 	c.func = func;
20442233 	c.sernum = sernum;
20452234 	c.arg = arg;
20462235 	c.net = net;
2236
+	c.skip_notify = skip_notify;
20472237 
20482238 	fib6_walk(net, &c.w);
20492239 }
20502240 
20512241 static void __fib6_clean_all(struct net *net,
20522242 			     int (*func)(struct fib6_info *, void *),
2053
-			     int sernum, void *arg)
2243
+			     int sernum, void *arg, bool skip_notify)
20542244 {
20552245 	struct fib6_table *table;
20562246 	struct hlist_head *head;
....@@ -2062,7 +2252,7 @@
20622252 		hlist_for_each_entry_rcu(table, head, tb6_hlist) {
20632253 			spin_lock_bh(&table->tb6_lock);
20642254 			fib6_clean_tree(net, &table->tb6_root,
2065
-					func, sernum, arg);
2255
+					func, sernum, arg, skip_notify);
20662256 			spin_unlock_bh(&table->tb6_lock);
20672257 		}
20682258 	}
....@@ -2072,14 +2262,21 @@
20722262 void fib6_clean_all(struct net *net, int (*func)(struct fib6_info *, void *),
20732263 		    void *arg)
20742264 {
2075
-	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
2265
+	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, false);
2266
+}
2267
+
2268
+void fib6_clean_all_skip_notify(struct net *net,
2269
+				int (*func)(struct fib6_info *, void *),
2270
+				void *arg)
2271
+{
2272
+	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg, true);
20762273 }
20772274 
20782275 static void fib6_flush_trees(struct net *net)
20792276 {
20802277 	int new_sernum = fib6_new_sernum(net);
20812278 
2082
-	__fib6_clean_all(net, NULL, new_sernum, NULL);
2279
+	__fib6_clean_all(net, NULL, new_sernum, NULL, false);
20832280 }
20842281 
20852282 /*
....@@ -2279,11 +2476,16 @@
22792476 }
22802477 
22812478 #ifdef CONFIG_PROC_FS
2282
-static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2479
+static int ipv6_route_native_seq_show(struct seq_file *seq, void *v)
22832480 {
22842481 	struct fib6_info *rt = v;
22852482 	struct ipv6_route_iter *iter = seq->private;
2483
+	struct fib6_nh *fib6_nh = rt->fib6_nh;
2484
+	unsigned int flags = rt->fib6_flags;
22862485 	const struct net_device *dev;
2486
+
2487
+	if (rt->nh)
2488
+		fib6_nh = nexthop_fib6_nh_bh(rt->nh);
22872489 
22882490 	seq_printf(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen);
22892491 
....@@ -2292,15 +2494,17 @@
22922494 #else
22932495 	seq_puts(seq, "00000000000000000000000000000000 00 ");
22942496 #endif
2295
-	if (rt->fib6_flags & RTF_GATEWAY)
2296
-		seq_printf(seq, "%pi6", &rt->fib6_nh.nh_gw);
2297
-	else
2497
+	if (fib6_nh->fib_nh_gw_family) {
2498
+		flags |= RTF_GATEWAY;
2499
+		seq_printf(seq, "%pi6", &fib6_nh->fib_nh_gw6);
2500
+	} else {
22982501 		seq_puts(seq, "00000000000000000000000000000000");
2502
+	}
22992503 
2300
-	dev = rt->fib6_nh.nh_dev;
2504
+	dev = fib6_nh->fib_nh_dev;
23012505 	seq_printf(seq, " %08x %08x %08x %08x %8s\n",
2302
-		   rt->fib6_metric, atomic_read(&rt->fib6_ref), 0,
2303
-		   rt->fib6_flags, dev ? dev->name : "");
2506
+		   rt->fib6_metric, refcount_read(&rt->fib6_ref), 0,
2507
+		   flags, dev ? dev->name : "");
23042508 	iter->w.leaf = NULL;
23052509 	return 0;
23062510 }
....@@ -2434,7 +2638,7 @@
24342638 	return w->node && !(w->state == FWS_U && w->node == w->root);
24352639 }
24362640 
2437
-static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2641
+static void ipv6_route_native_seq_stop(struct seq_file *seq, void *v)
24382642 	__releases(RCU_BH)
24392643 {
24402644 	struct net *net = seq_file_net(seq);
....@@ -2446,6 +2650,62 @@
24462650 	rcu_read_unlock_bh();
24472651 }
24482652 
2653
+#if IS_BUILTIN(CONFIG_IPV6) && defined(CONFIG_BPF_SYSCALL)
2654
+static int ipv6_route_prog_seq_show(struct bpf_prog *prog,
2655
+				    struct bpf_iter_meta *meta,
2656
+				    void *v)
2657
+{
2658
+	struct bpf_iter__ipv6_route ctx;
2659
+
2660
+	ctx.meta = meta;
2661
+	ctx.rt = v;
2662
+	return bpf_iter_run_prog(prog, &ctx);
2663
+}
2664
+
2665
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2666
+{
2667
+	struct ipv6_route_iter *iter = seq->private;
2668
+	struct bpf_iter_meta meta;
2669
+	struct bpf_prog *prog;
2670
+	int ret;
2671
+
2672
+	meta.seq = seq;
2673
+	prog = bpf_iter_get_info(&meta, false);
2674
+	if (!prog)
2675
+		return ipv6_route_native_seq_show(seq, v);
2676
+
2677
+	ret = ipv6_route_prog_seq_show(prog, &meta, v);
2678
+	iter->w.leaf = NULL;
2679
+
2680
+	return ret;
2681
+}
2682
+
2683
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2684
+{
2685
+	struct bpf_iter_meta meta;
2686
+	struct bpf_prog *prog;
2687
+
2688
+	if (!v) {
2689
+		meta.seq = seq;
2690
+		prog = bpf_iter_get_info(&meta, true);
2691
+		if (prog)
2692
+			(void)ipv6_route_prog_seq_show(prog, &meta, v);
2693
+	}
2694
+
2695
+	ipv6_route_native_seq_stop(seq, v);
2696
+}
2697
+#else
2698
+static int ipv6_route_seq_show(struct seq_file *seq, void *v)
2699
+{
2700
+	return ipv6_route_native_seq_show(seq, v);
2701
+}
2702
+
2703
+static void ipv6_route_seq_stop(struct seq_file *seq, void *v)
2704
+{
2705
+	ipv6_route_native_seq_stop(seq, v);
2706
+}
2707
+#endif
2708
+
24492709 const struct seq_operations ipv6_route_seq_ops = {
24502710 	.start	= ipv6_route_seq_start,
24512711 	.next	= ipv6_route_seq_next,