1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  *   Robert Olsson <robert.olsson@its.uu.se> Uppsala Universitet
5  *     & Swedish University of Agricultural Sciences.
6  *
7  *   Jens Laas <jens.laas@data.slu.se> Swedish University of
8  *     Agricultural Sciences.
9  *
10  *   Hans Liss <hans.liss@its.uu.se>  Uppsala Universitet
11  *
12  * This work is based on the LPC-trie which is originally described in:
13  *
14  * An experimental study of compression methods for dynamic tries
15  * Stefan Nilsson and Matti Tikkanen. Algorithmica, 33(1):19-33, 2002.
16  * https://www.csc.kth.se/~snilsson/software/dyntrie2/
17  *
18  * IP-address lookup using LC-tries. Stefan Nilsson and Gunnar Karlsson
19  * IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999
20  *
21  * Code from fib_hash has been reused which includes the following header:
22  *
23  * INET		An implementation of the TCP/IP protocol suite for the LINUX
24  *		operating system.  INET is implemented using the  BSD Socket
25  *		interface as the means of communication with the user level.
26  *
27  *		IPv4 FIB: lookup engine and maintenance routines.
28  *
29  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
30  *
31  * Substantial contributions to this work comes from:
32  *
33  *		David S. Miller, <davem@davemloft.net>
34  *		Stephen Hemminger <shemminger@osdl.org>
35  *		Paul E. McKenney <paulmck@us.ibm.com>
36  *		Patrick McHardy <kaber@trash.net>
37  */
38 #include <linux/cache.h>
39 #include <linux/uaccess.h>
40 #include <linux/bitops.h>
41 #include <linux/types.h>
42 #include <linux/kernel.h>
43 #include <linux/mm.h>
44 #include <linux/string.h>
45 #include <linux/socket.h>
46 #include <linux/sockios.h>
47 #include <linux/errno.h>
48 #include <linux/in.h>
49 #include <linux/inet.h>
50 #include <linux/inetdevice.h>
51 #include <linux/netdevice.h>
52 #include <linux/if_arp.h>
53 #include <linux/proc_fs.h>
54 #include <linux/rcupdate.h>
55 #include <linux/skbuff.h>
56 #include <linux/netlink.h>
57 #include <linux/init.h>
58 #include <linux/list.h>
59 #include <linux/slab.h>
60 #include <linux/export.h>
61 #include <linux/vmalloc.h>
62 #include <linux/notifier.h>
63 #include <net/net_namespace.h>
64 #include <net/inet_dscp.h>
65 #include <net/ip.h>
66 #include <net/protocol.h>
67 #include <net/route.h>
68 #include <net/tcp.h>
69 #include <net/sock.h>
70 #include <net/ip_fib.h>
71 #include <net/fib_notifier.h>
72 #include <trace/events/fib.h>
73 #include "fib_lookup.h"
74 
call_fib_entry_notifier(struct notifier_block * nb,enum fib_event_type event_type,u32 dst,int dst_len,struct fib_alias * fa,struct netlink_ext_ack * extack)75 static int call_fib_entry_notifier(struct notifier_block *nb,
76 				   enum fib_event_type event_type, u32 dst,
77 				   int dst_len, struct fib_alias *fa,
78 				   struct netlink_ext_ack *extack)
79 {
80 	struct fib_entry_notifier_info info = {
81 		.info.extack = extack,
82 		.dst = dst,
83 		.dst_len = dst_len,
84 		.fi = fa->fa_info,
85 		.dscp = fa->fa_dscp,
86 		.type = fa->fa_type,
87 		.tb_id = fa->tb_id,
88 	};
89 	return call_fib4_notifier(nb, event_type, &info.info);
90 }
91 
call_fib_entry_notifiers(struct net * net,enum fib_event_type event_type,u32 dst,int dst_len,struct fib_alias * fa,struct netlink_ext_ack * extack)92 static int call_fib_entry_notifiers(struct net *net,
93 				    enum fib_event_type event_type, u32 dst,
94 				    int dst_len, struct fib_alias *fa,
95 				    struct netlink_ext_ack *extack)
96 {
97 	struct fib_entry_notifier_info info = {
98 		.info.extack = extack,
99 		.dst = dst,
100 		.dst_len = dst_len,
101 		.fi = fa->fa_info,
102 		.dscp = fa->fa_dscp,
103 		.type = fa->fa_type,
104 		.tb_id = fa->tb_id,
105 	};
106 	return call_fib4_notifiers(net, event_type, &info.info);
107 }
108 
109 #define MAX_STAT_DEPTH 32
110 
111 #define KEYLENGTH	(8*sizeof(t_key))
112 #define KEY_MAX		((t_key)~0)
113 
114 typedef unsigned int t_key;
115 
116 #define IS_TRIE(n)	((n)->pos >= KEYLENGTH)
117 #define IS_TNODE(n)	((n)->bits)
118 #define IS_LEAF(n)	(!(n)->bits)
119 
120 struct key_vector {
121 	t_key key;
122 	unsigned char pos;		/* 2log(KEYLENGTH) bits needed */
123 	unsigned char bits;		/* 2log(KEYLENGTH) bits needed */
124 	unsigned char slen;
125 	union {
126 		/* This list pointer if valid if (pos | bits) == 0 (LEAF) */
127 		struct hlist_head leaf;
128 		/* This array is valid if (pos | bits) > 0 (TNODE) */
129 		DECLARE_FLEX_ARRAY(struct key_vector __rcu *, tnode);
130 	};
131 };
132 
133 struct tnode {
134 	struct rcu_head rcu;
135 	t_key empty_children;		/* KEYLENGTH bits needed */
136 	t_key full_children;		/* KEYLENGTH bits needed */
137 	struct key_vector __rcu *parent;
138 	struct key_vector kv[1];
139 #define tn_bits kv[0].bits
140 };
141 
142 #define TNODE_SIZE(n)	offsetof(struct tnode, kv[0].tnode[n])
143 #define LEAF_SIZE	TNODE_SIZE(1)
144 
145 #ifdef CONFIG_IP_FIB_TRIE_STATS
146 struct trie_use_stats {
147 	unsigned int gets;
148 	unsigned int backtrack;
149 	unsigned int semantic_match_passed;
150 	unsigned int semantic_match_miss;
151 	unsigned int null_node_hit;
152 	unsigned int resize_node_skipped;
153 };
154 #endif
155 
156 struct trie_stat {
157 	unsigned int totdepth;
158 	unsigned int maxdepth;
159 	unsigned int tnodes;
160 	unsigned int leaves;
161 	unsigned int nullpointers;
162 	unsigned int prefixes;
163 	unsigned int nodesizes[MAX_STAT_DEPTH];
164 };
165 
166 struct trie {
167 	struct key_vector kv[1];
168 #ifdef CONFIG_IP_FIB_TRIE_STATS
169 	struct trie_use_stats __percpu *stats;
170 #endif
171 };
172 
173 static struct key_vector *resize(struct trie *t, struct key_vector *tn);
174 static unsigned int tnode_free_size;
175 
176 /*
177  * synchronize_rcu after call_rcu for outstanding dirty memory; it should be
178  * especially useful before resizing the root node with PREEMPT_NONE configs;
179  * the value was obtained experimentally, aiming to avoid visible slowdown.
180  */
181 unsigned int sysctl_fib_sync_mem = 512 * 1024;
182 unsigned int sysctl_fib_sync_mem_min = 64 * 1024;
183 unsigned int sysctl_fib_sync_mem_max = 64 * 1024 * 1024;
184 
185 static struct kmem_cache *fn_alias_kmem __ro_after_init;
186 static struct kmem_cache *trie_leaf_kmem __ro_after_init;
187 
tn_info(struct key_vector * kv)188 static inline struct tnode *tn_info(struct key_vector *kv)
189 {
190 	return container_of(kv, struct tnode, kv[0]);
191 }
192 
193 /* caller must hold RTNL */
194 #define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
195 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
196 
197 /* caller must hold RCU read lock or RTNL */
198 #define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
199 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
200 
201 /* wrapper for rcu_assign_pointer */
node_set_parent(struct key_vector * n,struct key_vector * tp)202 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
203 {
204 	if (n)
205 		rcu_assign_pointer(tn_info(n)->parent, tp);
206 }
207 
208 #define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(n)->parent, p)
209 
210 /* This provides us with the number of children in this node, in the case of a
211  * leaf this will return 0 meaning none of the children are accessible.
212  */
child_length(const struct key_vector * tn)213 static inline unsigned long child_length(const struct key_vector *tn)
214 {
215 	return (1ul << tn->bits) & ~(1ul);
216 }
217 
218 #define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
219 
get_index(t_key key,struct key_vector * kv)220 static inline unsigned long get_index(t_key key, struct key_vector *kv)
221 {
222 	unsigned long index = key ^ kv->key;
223 
224 	if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
225 		return 0;
226 
227 	return index >> kv->pos;
228 }
229 
230 /* To understand this stuff, an understanding of keys and all their bits is
231  * necessary. Every node in the trie has a key associated with it, but not
232  * all of the bits in that key are significant.
233  *
234  * Consider a node 'n' and its parent 'tp'.
235  *
236  * If n is a leaf, every bit in its key is significant. Its presence is
237  * necessitated by path compression, since during a tree traversal (when
238  * searching for a leaf - unless we are doing an insertion) we will completely
239  * ignore all skipped bits we encounter. Thus we need to verify, at the end of
240  * a potentially successful search, that we have indeed been walking the
241  * correct key path.
242  *
243  * Note that we can never "miss" the correct key in the tree if present by
244  * following the wrong path. Path compression ensures that segments of the key
245  * that are the same for all keys with a given prefix are skipped, but the
246  * skipped part *is* identical for each node in the subtrie below the skipped
247  * bit! trie_insert() in this implementation takes care of that.
248  *
249  * if n is an internal node - a 'tnode' here, the various parts of its key
250  * have many different meanings.
251  *
252  * Example:
253  * _________________________________________________________________
254  * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
255  * -----------------------------------------------------------------
256  *  31  30  29  28  27  26  25  24  23  22  21  20  19  18  17  16
257  *
258  * _________________________________________________________________
259  * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
260  * -----------------------------------------------------------------
261  *  15  14  13  12  11  10   9   8   7   6   5   4   3   2   1   0
262  *
263  * tp->pos = 22
264  * tp->bits = 3
265  * n->pos = 13
266  * n->bits = 4
267  *
268  * First, let's just ignore the bits that come before the parent tp, that is
269  * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
270  * point we do not use them for anything.
271  *
272  * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
273  * index into the parent's child array. That is, they will be used to find
274  * 'n' among tp's children.
275  *
276  * The bits from (n->pos + n->bits) to (tp->pos - 1) - "S" - are skipped bits
277  * for the node n.
278  *
279  * All the bits we have seen so far are significant to the node n. The rest
280  * of the bits are really not needed or indeed known in n->key.
281  *
282  * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
283  * n's child array, and will of course be different for each child.
284  *
285  * The rest of the bits, from 0 to (n->pos -1) - "u" - are completely unknown
286  * at this point.
287  */
288 
289 static const int halve_threshold = 25;
290 static const int inflate_threshold = 50;
291 static const int halve_threshold_root = 15;
292 static const int inflate_threshold_root = 30;
293 
__alias_free_mem(struct rcu_head * head)294 static void __alias_free_mem(struct rcu_head *head)
295 {
296 	struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
297 	kmem_cache_free(fn_alias_kmem, fa);
298 }
299 
alias_free_mem_rcu(struct fib_alias * fa)300 static inline void alias_free_mem_rcu(struct fib_alias *fa)
301 {
302 	call_rcu(&fa->rcu, __alias_free_mem);
303 }
304 
305 #define TNODE_VMALLOC_MAX \
306 	ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
307 
__node_free_rcu(struct rcu_head * head)308 static void __node_free_rcu(struct rcu_head *head)
309 {
310 	struct tnode *n = container_of(head, struct tnode, rcu);
311 
312 	if (!n->tn_bits)
313 		kmem_cache_free(trie_leaf_kmem, n);
314 	else
315 		kvfree(n);
316 }
317 
318 #define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
319 
tnode_alloc(int bits)320 static struct tnode *tnode_alloc(int bits)
321 {
322 	size_t size;
323 
324 	/* verify bits is within bounds */
325 	if (bits > TNODE_VMALLOC_MAX)
326 		return NULL;
327 
328 	/* determine size and verify it is non-zero and didn't overflow */
329 	size = TNODE_SIZE(1ul << bits);
330 
331 	if (size <= PAGE_SIZE)
332 		return kzalloc(size, GFP_KERNEL);
333 	else
334 		return vzalloc(size);
335 }
336 
empty_child_inc(struct key_vector * n)337 static inline void empty_child_inc(struct key_vector *n)
338 {
339 	tn_info(n)->empty_children++;
340 
341 	if (!tn_info(n)->empty_children)
342 		tn_info(n)->full_children++;
343 }
344 
empty_child_dec(struct key_vector * n)345 static inline void empty_child_dec(struct key_vector *n)
346 {
347 	if (!tn_info(n)->empty_children)
348 		tn_info(n)->full_children--;
349 
350 	tn_info(n)->empty_children--;
351 }
352 
leaf_new(t_key key,struct fib_alias * fa)353 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
354 {
355 	struct key_vector *l;
356 	struct tnode *kv;
357 
358 	kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
359 	if (!kv)
360 		return NULL;
361 
362 	/* initialize key vector */
363 	l = kv->kv;
364 	l->key = key;
365 	l->pos = 0;
366 	l->bits = 0;
367 	l->slen = fa->fa_slen;
368 
369 	/* link leaf to fib alias */
370 	INIT_HLIST_HEAD(&l->leaf);
371 	hlist_add_head(&fa->fa_list, &l->leaf);
372 
373 	return l;
374 }
375 
tnode_new(t_key key,int pos,int bits)376 static struct key_vector *tnode_new(t_key key, int pos, int bits)
377 {
378 	unsigned int shift = pos + bits;
379 	struct key_vector *tn;
380 	struct tnode *tnode;
381 
382 	/* verify bits and pos their msb bits clear and values are valid */
383 	BUG_ON(!bits || (shift > KEYLENGTH));
384 
385 	tnode = tnode_alloc(bits);
386 	if (!tnode)
387 		return NULL;
388 
389 	pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
390 		 sizeof(struct key_vector *) << bits);
391 
392 	if (bits == KEYLENGTH)
393 		tnode->full_children = 1;
394 	else
395 		tnode->empty_children = 1ul << bits;
396 
397 	tn = tnode->kv;
398 	tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
399 	tn->pos = pos;
400 	tn->bits = bits;
401 	tn->slen = pos;
402 
403 	return tn;
404 }
405 
406 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
407  * and no bits are skipped. See discussion in dyntree paper p. 6
408  */
tnode_full(struct key_vector * tn,struct key_vector * n)409 static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
410 {
411 	return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
412 }
413 
414 /* Add a child at position i overwriting the old value.
415  * Update the value of full_children and empty_children.
416  */
put_child(struct key_vector * tn,unsigned long i,struct key_vector * n)417 static void put_child(struct key_vector *tn, unsigned long i,
418 		      struct key_vector *n)
419 {
420 	struct key_vector *chi = get_child(tn, i);
421 	int isfull, wasfull;
422 
423 	BUG_ON(i >= child_length(tn));
424 
425 	/* update emptyChildren, overflow into fullChildren */
426 	if (!n && chi)
427 		empty_child_inc(tn);
428 	if (n && !chi)
429 		empty_child_dec(tn);
430 
431 	/* update fullChildren */
432 	wasfull = tnode_full(tn, chi);
433 	isfull = tnode_full(tn, n);
434 
435 	if (wasfull && !isfull)
436 		tn_info(tn)->full_children--;
437 	else if (!wasfull && isfull)
438 		tn_info(tn)->full_children++;
439 
440 	if (n && (tn->slen < n->slen))
441 		tn->slen = n->slen;
442 
443 	rcu_assign_pointer(tn->tnode[i], n);
444 }
445 
update_children(struct key_vector * tn)446 static void update_children(struct key_vector *tn)
447 {
448 	unsigned long i;
449 
450 	/* update all of the child parent pointers */
451 	for (i = child_length(tn); i;) {
452 		struct key_vector *inode = get_child(tn, --i);
453 
454 		if (!inode)
455 			continue;
456 
457 		/* Either update the children of a tnode that
458 		 * already belongs to us or update the child
459 		 * to point to ourselves.
460 		 */
461 		if (node_parent(inode) == tn)
462 			update_children(inode);
463 		else
464 			node_set_parent(inode, tn);
465 	}
466 }
467 
put_child_root(struct key_vector * tp,t_key key,struct key_vector * n)468 static inline void put_child_root(struct key_vector *tp, t_key key,
469 				  struct key_vector *n)
470 {
471 	if (IS_TRIE(tp))
472 		rcu_assign_pointer(tp->tnode[0], n);
473 	else
474 		put_child(tp, get_index(key, tp), n);
475 }
476 
tnode_free_init(struct key_vector * tn)477 static inline void tnode_free_init(struct key_vector *tn)
478 {
479 	tn_info(tn)->rcu.next = NULL;
480 }
481 
tnode_free_append(struct key_vector * tn,struct key_vector * n)482 static inline void tnode_free_append(struct key_vector *tn,
483 				     struct key_vector *n)
484 {
485 	tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
486 	tn_info(tn)->rcu.next = &tn_info(n)->rcu;
487 }
488 
tnode_free(struct key_vector * tn)489 static void tnode_free(struct key_vector *tn)
490 {
491 	struct callback_head *head = &tn_info(tn)->rcu;
492 
493 	while (head) {
494 		head = head->next;
495 		tnode_free_size += TNODE_SIZE(1ul << tn->bits);
496 		node_free(tn);
497 
498 		tn = container_of(head, struct tnode, rcu)->kv;
499 	}
500 
501 	if (tnode_free_size >= READ_ONCE(sysctl_fib_sync_mem)) {
502 		tnode_free_size = 0;
503 		synchronize_rcu();
504 	}
505 }
506 
replace(struct trie * t,struct key_vector * oldtnode,struct key_vector * tn)507 static struct key_vector *replace(struct trie *t,
508 				  struct key_vector *oldtnode,
509 				  struct key_vector *tn)
510 {
511 	struct key_vector *tp = node_parent(oldtnode);
512 	unsigned long i;
513 
514 	/* setup the parent pointer out of and back into this node */
515 	NODE_INIT_PARENT(tn, tp);
516 	put_child_root(tp, tn->key, tn);
517 
518 	/* update all of the child parent pointers */
519 	update_children(tn);
520 
521 	/* all pointers should be clean so we are done */
522 	tnode_free(oldtnode);
523 
524 	/* resize children now that oldtnode is freed */
525 	for (i = child_length(tn); i;) {
526 		struct key_vector *inode = get_child(tn, --i);
527 
528 		/* resize child node */
529 		if (tnode_full(tn, inode))
530 			tn = resize(t, inode);
531 	}
532 
533 	return tp;
534 }
535 
inflate(struct trie * t,struct key_vector * oldtnode)536 static struct key_vector *inflate(struct trie *t,
537 				  struct key_vector *oldtnode)
538 {
539 	struct key_vector *tn;
540 	unsigned long i;
541 	t_key m;
542 
543 	pr_debug("In inflate\n");
544 
545 	tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
546 	if (!tn)
547 		goto notnode;
548 
549 	/* prepare oldtnode to be freed */
550 	tnode_free_init(oldtnode);
551 
552 	/* Assemble all of the pointers in our cluster, in this case that
553 	 * represents all of the pointers out of our allocated nodes that
554 	 * point to existing tnodes and the links between our allocated
555 	 * nodes.
556 	 */
557 	for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
558 		struct key_vector *inode = get_child(oldtnode, --i);
559 		struct key_vector *node0, *node1;
560 		unsigned long j, k;
561 
562 		/* An empty child */
563 		if (!inode)
564 			continue;
565 
566 		/* A leaf or an internal node with skipped bits */
567 		if (!tnode_full(oldtnode, inode)) {
568 			put_child(tn, get_index(inode->key, tn), inode);
569 			continue;
570 		}
571 
572 		/* drop the node in the old tnode free list */
573 		tnode_free_append(oldtnode, inode);
574 
575 		/* An internal node with two children */
576 		if (inode->bits == 1) {
577 			put_child(tn, 2 * i + 1, get_child(inode, 1));
578 			put_child(tn, 2 * i, get_child(inode, 0));
579 			continue;
580 		}
581 
582 		/* We will replace this node 'inode' with two new
583 		 * ones, 'node0' and 'node1', each with half of the
584 		 * original children. The two new nodes will have
585 		 * a position one bit further down the key and this
586 		 * means that the "significant" part of their keys
587 		 * (see the discussion near the top of this file)
588 		 * will differ by one bit, which will be "0" in
589 		 * node0's key and "1" in node1's key. Since we are
590 		 * moving the key position by one step, the bit that
591 		 * we are moving away from - the bit at position
592 		 * (tn->pos) - is the one that will differ between
593 		 * node0 and node1. So... we synthesize that bit in the
594 		 * two new keys.
595 		 */
596 		node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
597 		if (!node1)
598 			goto nomem;
599 		node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
600 
601 		tnode_free_append(tn, node1);
602 		if (!node0)
603 			goto nomem;
604 		tnode_free_append(tn, node0);
605 
606 		/* populate child pointers in new nodes */
607 		for (k = child_length(inode), j = k / 2; j;) {
608 			put_child(node1, --j, get_child(inode, --k));
609 			put_child(node0, j, get_child(inode, j));
610 			put_child(node1, --j, get_child(inode, --k));
611 			put_child(node0, j, get_child(inode, j));
612 		}
613 
614 		/* link new nodes to parent */
615 		NODE_INIT_PARENT(node1, tn);
616 		NODE_INIT_PARENT(node0, tn);
617 
618 		/* link parent to nodes */
619 		put_child(tn, 2 * i + 1, node1);
620 		put_child(tn, 2 * i, node0);
621 	}
622 
623 	/* setup the parent pointers into and out of this node */
624 	return replace(t, oldtnode, tn);
625 nomem:
626 	/* all pointers should be clean so we are done */
627 	tnode_free(tn);
628 notnode:
629 	return NULL;
630 }
631 
halve(struct trie * t,struct key_vector * oldtnode)632 static struct key_vector *halve(struct trie *t,
633 				struct key_vector *oldtnode)
634 {
635 	struct key_vector *tn;
636 	unsigned long i;
637 
638 	pr_debug("In halve\n");
639 
640 	tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
641 	if (!tn)
642 		goto notnode;
643 
644 	/* prepare oldtnode to be freed */
645 	tnode_free_init(oldtnode);
646 
647 	/* Assemble all of the pointers in our cluster, in this case that
648 	 * represents all of the pointers out of our allocated nodes that
649 	 * point to existing tnodes and the links between our allocated
650 	 * nodes.
651 	 */
652 	for (i = child_length(oldtnode); i;) {
653 		struct key_vector *node1 = get_child(oldtnode, --i);
654 		struct key_vector *node0 = get_child(oldtnode, --i);
655 		struct key_vector *inode;
656 
657 		/* At least one of the children is empty */
658 		if (!node1 || !node0) {
659 			put_child(tn, i / 2, node1 ? : node0);
660 			continue;
661 		}
662 
663 		/* Two nonempty children */
664 		inode = tnode_new(node0->key, oldtnode->pos, 1);
665 		if (!inode)
666 			goto nomem;
667 		tnode_free_append(tn, inode);
668 
669 		/* initialize pointers out of node */
670 		put_child(inode, 1, node1);
671 		put_child(inode, 0, node0);
672 		NODE_INIT_PARENT(inode, tn);
673 
674 		/* link parent to node */
675 		put_child(tn, i / 2, inode);
676 	}
677 
678 	/* setup the parent pointers into and out of this node */
679 	return replace(t, oldtnode, tn);
680 nomem:
681 	/* all pointers should be clean so we are done */
682 	tnode_free(tn);
683 notnode:
684 	return NULL;
685 }
686 
collapse(struct trie * t,struct key_vector * oldtnode)687 static struct key_vector *collapse(struct trie *t,
688 				   struct key_vector *oldtnode)
689 {
690 	struct key_vector *n, *tp;
691 	unsigned long i;
692 
693 	/* scan the tnode looking for that one child that might still exist */
694 	for (n = NULL, i = child_length(oldtnode); !n && i;)
695 		n = get_child(oldtnode, --i);
696 
697 	/* compress one level */
698 	tp = node_parent(oldtnode);
699 	put_child_root(tp, oldtnode->key, n);
700 	node_set_parent(n, tp);
701 
702 	/* drop dead node */
703 	node_free(oldtnode);
704 
705 	return tp;
706 }
707 
update_suffix(struct key_vector * tn)708 static unsigned char update_suffix(struct key_vector *tn)
709 {
710 	unsigned char slen = tn->pos;
711 	unsigned long stride, i;
712 	unsigned char slen_max;
713 
714 	/* only vector 0 can have a suffix length greater than or equal to
715 	 * tn->pos + tn->bits, the second highest node will have a suffix
716 	 * length at most of tn->pos + tn->bits - 1
717 	 */
718 	slen_max = min_t(unsigned char, tn->pos + tn->bits - 1, tn->slen);
719 
720 	/* search though the list of children looking for nodes that might
721 	 * have a suffix greater than the one we currently have.  This is
722 	 * why we start with a stride of 2 since a stride of 1 would
723 	 * represent the nodes with suffix length equal to tn->pos
724 	 */
725 	for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
726 		struct key_vector *n = get_child(tn, i);
727 
728 		if (!n || (n->slen <= slen))
729 			continue;
730 
731 		/* update stride and slen based on new value */
732 		stride <<= (n->slen - slen);
733 		slen = n->slen;
734 		i &= ~(stride - 1);
735 
736 		/* stop searching if we have hit the maximum possible value */
737 		if (slen >= slen_max)
738 			break;
739 	}
740 
741 	tn->slen = slen;
742 
743 	return slen;
744 }
745 
746 /* From "Implementing a dynamic compressed trie" by Stefan Nilsson of
747  * the Helsinki University of Technology and Matti Tikkanen of Nokia
748  * Telecommunications, page 6:
749  * "A node is doubled if the ratio of non-empty children to all
750  * children in the *doubled* node is at least 'high'."
751  *
752  * 'high' in this instance is the variable 'inflate_threshold'. It
753  * is expressed as a percentage, so we multiply it with
754  * child_length() and instead of multiplying by 2 (since the
755  * child array will be doubled by inflate()) and multiplying
756  * the left-hand side by 100 (to handle the percentage thing) we
757  * multiply the left-hand side by 50.
758  *
759  * The left-hand side may look a bit weird: child_length(tn)
760  * - tn->empty_children is of course the number of non-null children
761  * in the current node. tn->full_children is the number of "full"
762  * children, that is non-null tnodes with a skip value of 0.
763  * All of those will be doubled in the resulting inflated tnode, so
764  * we just count them one extra time here.
765  *
766  * A clearer way to write this would be:
767  *
768  * to_be_doubled = tn->full_children;
769  * not_to_be_doubled = child_length(tn) - tn->empty_children -
770  *     tn->full_children;
771  *
772  * new_child_length = child_length(tn) * 2;
773  *
774  * new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
775  *      new_child_length;
776  * if (new_fill_factor >= inflate_threshold)
777  *
778  * ...and so on, tho it would mess up the while () loop.
779  *
780  * anyway,
781  * 100 * (not_to_be_doubled + 2*to_be_doubled) / new_child_length >=
782  *      inflate_threshold
783  *
784  * avoid a division:
785  * 100 * (not_to_be_doubled + 2*to_be_doubled) >=
786  *      inflate_threshold * new_child_length
787  *
788  * expand not_to_be_doubled and to_be_doubled, and shorten:
789  * 100 * (child_length(tn) - tn->empty_children +
790  *    tn->full_children) >= inflate_threshold * new_child_length
791  *
792  * expand new_child_length:
793  * 100 * (child_length(tn) - tn->empty_children +
794  *    tn->full_children) >=
795  *      inflate_threshold * child_length(tn) * 2
796  *
797  * shorten again:
798  * 50 * (tn->full_children + child_length(tn) -
799  *    tn->empty_children) >= inflate_threshold *
800  *    child_length(tn)
801  *
802  */
should_inflate(struct key_vector * tp,struct key_vector * tn)803 static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
804 {
805 	unsigned long used = child_length(tn);
806 	unsigned long threshold = used;
807 
808 	/* Keep root node larger */
809 	threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
810 	used -= tn_info(tn)->empty_children;
811 	used += tn_info(tn)->full_children;
812 
813 	/* if bits == KEYLENGTH then pos = 0, and will fail below */
814 
815 	return (used > 1) && tn->pos && ((50 * used) >= threshold);
816 }
817 
should_halve(struct key_vector * tp,struct key_vector * tn)818 static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
819 {
820 	unsigned long used = child_length(tn);
821 	unsigned long threshold = used;
822 
823 	/* Keep root node larger */
824 	threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
825 	used -= tn_info(tn)->empty_children;
826 
827 	/* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
828 
829 	return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
830 }
831 
should_collapse(struct key_vector * tn)832 static inline bool should_collapse(struct key_vector *tn)
833 {
834 	unsigned long used = child_length(tn);
835 
836 	used -= tn_info(tn)->empty_children;
837 
838 	/* account for bits == KEYLENGTH case */
839 	if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
840 		used -= KEY_MAX;
841 
842 	/* One child or none, time to drop us from the trie */
843 	return used < 2;
844 }
845 
846 #define MAX_WORK 10
resize(struct trie * t,struct key_vector * tn)847 static struct key_vector *resize(struct trie *t, struct key_vector *tn)
848 {
849 #ifdef CONFIG_IP_FIB_TRIE_STATS
850 	struct trie_use_stats __percpu *stats = t->stats;
851 #endif
852 	struct key_vector *tp = node_parent(tn);
853 	unsigned long cindex = get_index(tn->key, tp);
854 	int max_work = MAX_WORK;
855 
856 	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
857 		 tn, inflate_threshold, halve_threshold);
858 
859 	/* track the tnode via the pointer from the parent instead of
860 	 * doing it ourselves.  This way we can let RCU fully do its
861 	 * thing without us interfering
862 	 */
863 	BUG_ON(tn != get_child(tp, cindex));
864 
865 	/* Double as long as the resulting node has a number of
866 	 * nonempty nodes that are above the threshold.
867 	 */
868 	while (should_inflate(tp, tn) && max_work) {
869 		tp = inflate(t, tn);
870 		if (!tp) {
871 #ifdef CONFIG_IP_FIB_TRIE_STATS
872 			this_cpu_inc(stats->resize_node_skipped);
873 #endif
874 			break;
875 		}
876 
877 		max_work--;
878 		tn = get_child(tp, cindex);
879 	}
880 
881 	/* update parent in case inflate failed */
882 	tp = node_parent(tn);
883 
884 	/* Return if at least one inflate is run */
885 	if (max_work != MAX_WORK)
886 		return tp;
887 
888 	/* Halve as long as the number of empty children in this
889 	 * node is above threshold.
890 	 */
891 	while (should_halve(tp, tn) && max_work) {
892 		tp = halve(t, tn);
893 		if (!tp) {
894 #ifdef CONFIG_IP_FIB_TRIE_STATS
895 			this_cpu_inc(stats->resize_node_skipped);
896 #endif
897 			break;
898 		}
899 
900 		max_work--;
901 		tn = get_child(tp, cindex);
902 	}
903 
904 	/* Only one child remains */
905 	if (should_collapse(tn))
906 		return collapse(t, tn);
907 
908 	/* update parent in case halve failed */
909 	return node_parent(tn);
910 }
911 
node_pull_suffix(struct key_vector * tn,unsigned char slen)912 static void node_pull_suffix(struct key_vector *tn, unsigned char slen)
913 {
914 	unsigned char node_slen = tn->slen;
915 
916 	while ((node_slen > tn->pos) && (node_slen > slen)) {
917 		slen = update_suffix(tn);
918 		if (node_slen == slen)
919 			break;
920 
921 		tn = node_parent(tn);
922 		node_slen = tn->slen;
923 	}
924 }
925 
node_push_suffix(struct key_vector * tn,unsigned char slen)926 static void node_push_suffix(struct key_vector *tn, unsigned char slen)
927 {
928 	while (tn->slen < slen) {
929 		tn->slen = slen;
930 		tn = node_parent(tn);
931 	}
932 }
933 
934 /* rcu_read_lock needs to be hold by caller from readside */
fib_find_node(struct trie * t,struct key_vector ** tp,u32 key)935 static struct key_vector *fib_find_node(struct trie *t,
936 					struct key_vector **tp, u32 key)
937 {
938 	struct key_vector *pn, *n = t->kv;
939 	unsigned long index = 0;
940 
941 	do {
942 		pn = n;
943 		n = get_child_rcu(n, index);
944 
945 		if (!n)
946 			break;
947 
948 		index = get_cindex(key, n);
949 
950 		/* This bit of code is a bit tricky but it combines multiple
951 		 * checks into a single check.  The prefix consists of the
952 		 * prefix plus zeros for the bits in the cindex. The index
953 		 * is the difference between the key and this value.  From
954 		 * this we can actually derive several pieces of data.
955 		 *   if (index >= (1ul << bits))
956 		 *     we have a mismatch in skip bits and failed
957 		 *   else
958 		 *     we know the value is cindex
959 		 *
960 		 * This check is safe even if bits == KEYLENGTH due to the
961 		 * fact that we can only allocate a node with 32 bits if a
962 		 * long is greater than 32 bits.
963 		 */
964 		if (index >= (1ul << n->bits)) {
965 			n = NULL;
966 			break;
967 		}
968 
969 		/* keep searching until we find a perfect match leaf or NULL */
970 	} while (IS_TNODE(n));
971 
972 	*tp = pn;
973 
974 	return n;
975 }
976 
977 /* Return the first fib alias matching DSCP with
978  * priority less than or equal to PRIO.
979  * If 'find_first' is set, return the first matching
980  * fib alias, regardless of DSCP and priority.
981  */
fib_find_alias(struct hlist_head * fah,u8 slen,dscp_t dscp,u32 prio,u32 tb_id,bool find_first)982 static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
983 					dscp_t dscp, u32 prio, u32 tb_id,
984 					bool find_first)
985 {
986 	struct fib_alias *fa;
987 
988 	if (!fah)
989 		return NULL;
990 
991 	hlist_for_each_entry(fa, fah, fa_list) {
992 		/* Avoid Sparse warning when using dscp_t in inequalities */
993 		u8 __fa_dscp = inet_dscp_to_dsfield(fa->fa_dscp);
994 		u8 __dscp = inet_dscp_to_dsfield(dscp);
995 
996 		if (fa->fa_slen < slen)
997 			continue;
998 		if (fa->fa_slen != slen)
999 			break;
1000 		if (fa->tb_id > tb_id)
1001 			continue;
1002 		if (fa->tb_id != tb_id)
1003 			break;
1004 		if (find_first)
1005 			return fa;
1006 		if (__fa_dscp > __dscp)
1007 			continue;
1008 		if (fa->fa_info->fib_priority >= prio || __fa_dscp < __dscp)
1009 			return fa;
1010 	}
1011 
1012 	return NULL;
1013 }
1014 
1015 static struct fib_alias *
fib_find_matching_alias(struct net * net,const struct fib_rt_info * fri)1016 fib_find_matching_alias(struct net *net, const struct fib_rt_info *fri)
1017 {
1018 	u8 slen = KEYLENGTH - fri->dst_len;
1019 	struct key_vector *l, *tp;
1020 	struct fib_table *tb;
1021 	struct fib_alias *fa;
1022 	struct trie *t;
1023 
1024 	tb = fib_get_table(net, fri->tb_id);
1025 	if (!tb)
1026 		return NULL;
1027 
1028 	t = (struct trie *)tb->tb_data;
1029 	l = fib_find_node(t, &tp, be32_to_cpu(fri->dst));
1030 	if (!l)
1031 		return NULL;
1032 
1033 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
1034 		if (fa->fa_slen == slen && fa->tb_id == fri->tb_id &&
1035 		    fa->fa_dscp == fri->dscp && fa->fa_info == fri->fi &&
1036 		    fa->fa_type == fri->type)
1037 			return fa;
1038 	}
1039 
1040 	return NULL;
1041 }
1042 
fib_alias_hw_flags_set(struct net * net,const struct fib_rt_info * fri)1043 void fib_alias_hw_flags_set(struct net *net, const struct fib_rt_info *fri)
1044 {
1045 	u8 fib_notify_on_flag_change;
1046 	struct fib_alias *fa_match;
1047 	struct sk_buff *skb;
1048 	int err;
1049 
1050 	rcu_read_lock();
1051 
1052 	fa_match = fib_find_matching_alias(net, fri);
1053 	if (!fa_match)
1054 		goto out;
1055 
1056 	/* These are paired with the WRITE_ONCE() happening in this function.
1057 	 * The reason is that we are only protected by RCU at this point.
1058 	 */
1059 	if (READ_ONCE(fa_match->offload) == fri->offload &&
1060 	    READ_ONCE(fa_match->trap) == fri->trap &&
1061 	    READ_ONCE(fa_match->offload_failed) == fri->offload_failed)
1062 		goto out;
1063 
1064 	WRITE_ONCE(fa_match->offload, fri->offload);
1065 	WRITE_ONCE(fa_match->trap, fri->trap);
1066 
1067 	fib_notify_on_flag_change = READ_ONCE(net->ipv4.sysctl_fib_notify_on_flag_change);
1068 
1069 	/* 2 means send notifications only if offload_failed was changed. */
1070 	if (fib_notify_on_flag_change == 2 &&
1071 	    READ_ONCE(fa_match->offload_failed) == fri->offload_failed)
1072 		goto out;
1073 
1074 	WRITE_ONCE(fa_match->offload_failed, fri->offload_failed);
1075 
1076 	if (!fib_notify_on_flag_change)
1077 		goto out;
1078 
1079 	skb = nlmsg_new(fib_nlmsg_size(fa_match->fa_info), GFP_ATOMIC);
1080 	if (!skb) {
1081 		err = -ENOBUFS;
1082 		goto errout;
1083 	}
1084 
1085 	err = fib_dump_info(skb, 0, 0, RTM_NEWROUTE, fri, 0);
1086 	if (err < 0) {
1087 		/* -EMSGSIZE implies BUG in fib_nlmsg_size() */
1088 		WARN_ON(err == -EMSGSIZE);
1089 		kfree_skb(skb);
1090 		goto errout;
1091 	}
1092 
1093 	rtnl_notify(skb, net, 0, RTNLGRP_IPV4_ROUTE, NULL, GFP_ATOMIC);
1094 	goto out;
1095 
1096 errout:
1097 	rtnl_set_sk_err(net, RTNLGRP_IPV4_ROUTE, err);
1098 out:
1099 	rcu_read_unlock();
1100 }
1101 EXPORT_SYMBOL_GPL(fib_alias_hw_flags_set);
1102 
trie_rebalance(struct trie * t,struct key_vector * tn)1103 static void trie_rebalance(struct trie *t, struct key_vector *tn)
1104 {
1105 	while (!IS_TRIE(tn))
1106 		tn = resize(t, tn);
1107 }
1108 
fib_insert_node(struct trie * t,struct key_vector * tp,struct fib_alias * new,t_key key)1109 static int fib_insert_node(struct trie *t, struct key_vector *tp,
1110 			   struct fib_alias *new, t_key key)
1111 {
1112 	struct key_vector *n, *l;
1113 
1114 	l = leaf_new(key, new);
1115 	if (!l)
1116 		goto noleaf;
1117 
1118 	/* retrieve child from parent node */
1119 	n = get_child(tp, get_index(key, tp));
1120 
1121 	/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
1122 	 *
1123 	 *  Add a new tnode here
1124 	 *  first tnode need some special handling
1125 	 *  leaves us in position for handling as case 3
1126 	 */
1127 	if (n) {
1128 		struct key_vector *tn;
1129 
1130 		tn = tnode_new(key, __fls(key ^ n->key), 1);
1131 		if (!tn)
1132 			goto notnode;
1133 
1134 		/* initialize routes out of node */
1135 		NODE_INIT_PARENT(tn, tp);
1136 		put_child(tn, get_index(key, tn) ^ 1, n);
1137 
1138 		/* start adding routes into the node */
1139 		put_child_root(tp, key, tn);
1140 		node_set_parent(n, tn);
1141 
1142 		/* parent now has a NULL spot where the leaf can go */
1143 		tp = tn;
1144 	}
1145 
1146 	/* Case 3: n is NULL, and will just insert a new leaf */
1147 	node_push_suffix(tp, new->fa_slen);
1148 	NODE_INIT_PARENT(l, tp);
1149 	put_child_root(tp, key, l);
1150 	trie_rebalance(t, tp);
1151 
1152 	return 0;
1153 notnode:
1154 	node_free(l);
1155 noleaf:
1156 	return -ENOMEM;
1157 }
1158 
fib_insert_alias(struct trie * t,struct key_vector * tp,struct key_vector * l,struct fib_alias * new,struct fib_alias * fa,t_key key)1159 static int fib_insert_alias(struct trie *t, struct key_vector *tp,
1160 			    struct key_vector *l, struct fib_alias *new,
1161 			    struct fib_alias *fa, t_key key)
1162 {
1163 	if (!l)
1164 		return fib_insert_node(t, tp, new, key);
1165 
1166 	if (fa) {
1167 		hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
1168 	} else {
1169 		struct fib_alias *last;
1170 
1171 		hlist_for_each_entry(last, &l->leaf, fa_list) {
1172 			if (new->fa_slen < last->fa_slen)
1173 				break;
1174 			if ((new->fa_slen == last->fa_slen) &&
1175 			    (new->tb_id > last->tb_id))
1176 				break;
1177 			fa = last;
1178 		}
1179 
1180 		if (fa)
1181 			hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
1182 		else
1183 			hlist_add_head_rcu(&new->fa_list, &l->leaf);
1184 	}
1185 
1186 	/* if we added to the tail node then we need to update slen */
1187 	if (l->slen < new->fa_slen) {
1188 		l->slen = new->fa_slen;
1189 		node_push_suffix(tp, new->fa_slen);
1190 	}
1191 
1192 	return 0;
1193 }
1194 
fib_valid_key_len(u32 key,u8 plen,struct netlink_ext_ack * extack)1195 static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
1196 {
1197 	if (plen > KEYLENGTH) {
1198 		NL_SET_ERR_MSG(extack, "Invalid prefix length");
1199 		return false;
1200 	}
1201 
1202 	if ((plen < KEYLENGTH) && (key << plen)) {
1203 		NL_SET_ERR_MSG(extack,
1204 			       "Invalid prefix for given prefix length");
1205 		return false;
1206 	}
1207 
1208 	return true;
1209 }
1210 
1211 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1212 			     struct key_vector *l, struct fib_alias *old);
1213 
1214 /* Caller must hold RTNL. */
fib_table_insert(struct net * net,struct fib_table * tb,struct fib_config * cfg,struct netlink_ext_ack * extack)1215 int fib_table_insert(struct net *net, struct fib_table *tb,
1216 		     struct fib_config *cfg, struct netlink_ext_ack *extack)
1217 {
1218 	struct trie *t = (struct trie *)tb->tb_data;
1219 	struct fib_alias *fa, *new_fa;
1220 	struct key_vector *l, *tp;
1221 	u16 nlflags = NLM_F_EXCL;
1222 	struct fib_info *fi;
1223 	u8 plen = cfg->fc_dst_len;
1224 	u8 slen = KEYLENGTH - plen;
1225 	dscp_t dscp;
1226 	u32 key;
1227 	int err;
1228 
1229 	key = ntohl(cfg->fc_dst);
1230 
1231 	if (!fib_valid_key_len(key, plen, extack))
1232 		return -EINVAL;
1233 
1234 	pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
1235 
1236 	fi = fib_create_info(cfg, extack);
1237 	if (IS_ERR(fi)) {
1238 		err = PTR_ERR(fi);
1239 		goto err;
1240 	}
1241 
1242 	dscp = cfg->fc_dscp;
1243 	l = fib_find_node(t, &tp, key);
1244 	fa = l ? fib_find_alias(&l->leaf, slen, dscp, fi->fib_priority,
1245 				tb->tb_id, false) : NULL;
1246 
1247 	/* Now fa, if non-NULL, points to the first fib alias
1248 	 * with the same keys [prefix,dscp,priority], if such key already
1249 	 * exists or to the node before which we will insert new one.
1250 	 *
1251 	 * If fa is NULL, we will need to allocate a new one and
1252 	 * insert to the tail of the section matching the suffix length
1253 	 * of the new alias.
1254 	 */
1255 
1256 	if (fa && fa->fa_dscp == dscp &&
1257 	    fa->fa_info->fib_priority == fi->fib_priority) {
1258 		struct fib_alias *fa_first, *fa_match;
1259 
1260 		err = -EEXIST;
1261 		if (cfg->fc_nlflags & NLM_F_EXCL)
1262 			goto out;
1263 
1264 		nlflags &= ~NLM_F_EXCL;
1265 
1266 		/* We have 2 goals:
1267 		 * 1. Find exact match for type, scope, fib_info to avoid
1268 		 * duplicate routes
1269 		 * 2. Find next 'fa' (or head), NLM_F_APPEND inserts before it
1270 		 */
1271 		fa_match = NULL;
1272 		fa_first = fa;
1273 		hlist_for_each_entry_from(fa, fa_list) {
1274 			if ((fa->fa_slen != slen) ||
1275 			    (fa->tb_id != tb->tb_id) ||
1276 			    (fa->fa_dscp != dscp))
1277 				break;
1278 			if (fa->fa_info->fib_priority != fi->fib_priority)
1279 				break;
1280 			if (fa->fa_type == cfg->fc_type &&
1281 			    fa->fa_info == fi) {
1282 				fa_match = fa;
1283 				break;
1284 			}
1285 		}
1286 
1287 		if (cfg->fc_nlflags & NLM_F_REPLACE) {
1288 			struct fib_info *fi_drop;
1289 			u8 state;
1290 
1291 			nlflags |= NLM_F_REPLACE;
1292 			fa = fa_first;
1293 			if (fa_match) {
1294 				if (fa == fa_match)
1295 					err = 0;
1296 				goto out;
1297 			}
1298 			err = -ENOBUFS;
1299 			new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1300 			if (!new_fa)
1301 				goto out;
1302 
1303 			fi_drop = fa->fa_info;
1304 			new_fa->fa_dscp = fa->fa_dscp;
1305 			new_fa->fa_info = fi;
1306 			new_fa->fa_type = cfg->fc_type;
1307 			state = fa->fa_state;
1308 			new_fa->fa_state = state & ~FA_S_ACCESSED;
1309 			new_fa->fa_slen = fa->fa_slen;
1310 			new_fa->tb_id = tb->tb_id;
1311 			new_fa->fa_default = -1;
1312 			new_fa->offload = 0;
1313 			new_fa->trap = 0;
1314 			new_fa->offload_failed = 0;
1315 
1316 			hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
1317 
1318 			if (fib_find_alias(&l->leaf, fa->fa_slen, 0, 0,
1319 					   tb->tb_id, true) == new_fa) {
1320 				enum fib_event_type fib_event;
1321 
1322 				fib_event = FIB_EVENT_ENTRY_REPLACE;
1323 				err = call_fib_entry_notifiers(net, fib_event,
1324 							       key, plen,
1325 							       new_fa, extack);
1326 				if (err) {
1327 					hlist_replace_rcu(&new_fa->fa_list,
1328 							  &fa->fa_list);
1329 					goto out_free_new_fa;
1330 				}
1331 			}
1332 
1333 			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
1334 				  tb->tb_id, &cfg->fc_nlinfo, nlflags);
1335 
1336 			alias_free_mem_rcu(fa);
1337 
1338 			fib_release_info(fi_drop);
1339 			if (state & FA_S_ACCESSED)
1340 				rt_cache_flush(cfg->fc_nlinfo.nl_net);
1341 
1342 			goto succeeded;
1343 		}
1344 		/* Error if we find a perfect match which
1345 		 * uses the same scope, type, and nexthop
1346 		 * information.
1347 		 */
1348 		if (fa_match)
1349 			goto out;
1350 
1351 		if (cfg->fc_nlflags & NLM_F_APPEND)
1352 			nlflags |= NLM_F_APPEND;
1353 		else
1354 			fa = fa_first;
1355 	}
1356 	err = -ENOENT;
1357 	if (!(cfg->fc_nlflags & NLM_F_CREATE))
1358 		goto out;
1359 
1360 	nlflags |= NLM_F_CREATE;
1361 	err = -ENOBUFS;
1362 	new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1363 	if (!new_fa)
1364 		goto out;
1365 
1366 	new_fa->fa_info = fi;
1367 	new_fa->fa_dscp = dscp;
1368 	new_fa->fa_type = cfg->fc_type;
1369 	new_fa->fa_state = 0;
1370 	new_fa->fa_slen = slen;
1371 	new_fa->tb_id = tb->tb_id;
1372 	new_fa->fa_default = -1;
1373 	new_fa->offload = 0;
1374 	new_fa->trap = 0;
1375 	new_fa->offload_failed = 0;
1376 
1377 	/* Insert new entry to the list. */
1378 	err = fib_insert_alias(t, tp, l, new_fa, fa, key);
1379 	if (err)
1380 		goto out_free_new_fa;
1381 
1382 	/* The alias was already inserted, so the node must exist. */
1383 	l = l ? l : fib_find_node(t, &tp, key);
1384 	if (WARN_ON_ONCE(!l)) {
1385 		err = -ENOENT;
1386 		goto out_free_new_fa;
1387 	}
1388 
1389 	if (fib_find_alias(&l->leaf, new_fa->fa_slen, 0, 0, tb->tb_id, true) ==
1390 	    new_fa) {
1391 		enum fib_event_type fib_event;
1392 
1393 		fib_event = FIB_EVENT_ENTRY_REPLACE;
1394 		err = call_fib_entry_notifiers(net, fib_event, key, plen,
1395 					       new_fa, extack);
1396 		if (err)
1397 			goto out_remove_new_fa;
1398 	}
1399 
1400 	if (!plen)
1401 		tb->tb_num_default++;
1402 
1403 	rt_cache_flush(cfg->fc_nlinfo.nl_net);
1404 	rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
1405 		  &cfg->fc_nlinfo, nlflags);
1406 succeeded:
1407 	return 0;
1408 
1409 out_remove_new_fa:
1410 	fib_remove_alias(t, tp, l, new_fa);
1411 out_free_new_fa:
1412 	kmem_cache_free(fn_alias_kmem, new_fa);
1413 out:
1414 	fib_release_info(fi);
1415 err:
1416 	return err;
1417 }
1418 
prefix_mismatch(t_key key,struct key_vector * n)1419 static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
1420 {
1421 	t_key prefix = n->key;
1422 
1423 	return (key ^ prefix) & (prefix | -prefix);
1424 }
1425 
fib_lookup_good_nhc(const struct fib_nh_common * nhc,int fib_flags,const struct flowi4 * flp)1426 bool fib_lookup_good_nhc(const struct fib_nh_common *nhc, int fib_flags,
1427 			 const struct flowi4 *flp)
1428 {
1429 	if (nhc->nhc_flags & RTNH_F_DEAD)
1430 		return false;
1431 
1432 	if (ip_ignore_linkdown(nhc->nhc_dev) &&
1433 	    nhc->nhc_flags & RTNH_F_LINKDOWN &&
1434 	    !(fib_flags & FIB_LOOKUP_IGNORE_LINKSTATE))
1435 		return false;
1436 
1437 	if (flp->flowi4_oif && flp->flowi4_oif != nhc->nhc_oif)
1438 		return false;
1439 
1440 	return true;
1441 }
1442 
1443 /* should be called with rcu_read_lock */
fib_table_lookup(struct fib_table * tb,const struct flowi4 * flp,struct fib_result * res,int fib_flags)1444 int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
1445 		     struct fib_result *res, int fib_flags)
1446 {
1447 	struct trie *t = (struct trie *) tb->tb_data;
1448 #ifdef CONFIG_IP_FIB_TRIE_STATS
1449 	struct trie_use_stats __percpu *stats = t->stats;
1450 #endif
1451 	const t_key key = ntohl(flp->daddr);
1452 	struct key_vector *n, *pn;
1453 	struct fib_alias *fa;
1454 	unsigned long index;
1455 	t_key cindex;
1456 
1457 	pn = t->kv;
1458 	cindex = 0;
1459 
1460 	n = get_child_rcu(pn, cindex);
1461 	if (!n) {
1462 		trace_fib_table_lookup(tb->tb_id, flp, NULL, -EAGAIN);
1463 		return -EAGAIN;
1464 	}
1465 
1466 #ifdef CONFIG_IP_FIB_TRIE_STATS
1467 	this_cpu_inc(stats->gets);
1468 #endif
1469 
1470 	/* Step 1: Travel to the longest prefix match in the trie */
1471 	for (;;) {
1472 		index = get_cindex(key, n);
1473 
1474 		/* This bit of code is a bit tricky but it combines multiple
1475 		 * checks into a single check.  The prefix consists of the
1476 		 * prefix plus zeros for the "bits" in the prefix. The index
1477 		 * is the difference between the key and this value.  From
1478 		 * this we can actually derive several pieces of data.
1479 		 *   if (index >= (1ul << bits))
1480 		 *     we have a mismatch in skip bits and failed
1481 		 *   else
1482 		 *     we know the value is cindex
1483 		 *
1484 		 * This check is safe even if bits == KEYLENGTH due to the
1485 		 * fact that we can only allocate a node with 32 bits if a
1486 		 * long is greater than 32 bits.
1487 		 */
1488 		if (index >= (1ul << n->bits))
1489 			break;
1490 
1491 		/* we have found a leaf. Prefixes have already been compared */
1492 		if (IS_LEAF(n))
1493 			goto found;
1494 
1495 		/* only record pn and cindex if we are going to be chopping
1496 		 * bits later.  Otherwise we are just wasting cycles.
1497 		 */
1498 		if (n->slen > n->pos) {
1499 			pn = n;
1500 			cindex = index;
1501 		}
1502 
1503 		n = get_child_rcu(n, index);
1504 		if (unlikely(!n))
1505 			goto backtrace;
1506 	}
1507 
1508 	/* Step 2: Sort out leaves and begin backtracing for longest prefix */
1509 	for (;;) {
1510 		/* record the pointer where our next node pointer is stored */
1511 		struct key_vector __rcu **cptr = n->tnode;
1512 
1513 		/* This test verifies that none of the bits that differ
1514 		 * between the key and the prefix exist in the region of
1515 		 * the lsb and higher in the prefix.
1516 		 */
1517 		if (unlikely(prefix_mismatch(key, n)) || (n->slen == n->pos))
1518 			goto backtrace;
1519 
1520 		/* exit out and process leaf */
1521 		if (unlikely(IS_LEAF(n)))
1522 			break;
1523 
1524 		/* Don't bother recording parent info.  Since we are in
1525 		 * prefix match mode we will have to come back to wherever
1526 		 * we started this traversal anyway
1527 		 */
1528 
1529 		while ((n = rcu_dereference(*cptr)) == NULL) {
1530 backtrace:
1531 #ifdef CONFIG_IP_FIB_TRIE_STATS
1532 			if (!n)
1533 				this_cpu_inc(stats->null_node_hit);
1534 #endif
1535 			/* If we are at cindex 0 there are no more bits for
1536 			 * us to strip at this level so we must ascend back
1537 			 * up one level to see if there are any more bits to
1538 			 * be stripped there.
1539 			 */
1540 			while (!cindex) {
1541 				t_key pkey = pn->key;
1542 
1543 				/* If we don't have a parent then there is
1544 				 * nothing for us to do as we do not have any
1545 				 * further nodes to parse.
1546 				 */
1547 				if (IS_TRIE(pn)) {
1548 					trace_fib_table_lookup(tb->tb_id, flp,
1549 							       NULL, -EAGAIN);
1550 					return -EAGAIN;
1551 				}
1552 #ifdef CONFIG_IP_FIB_TRIE_STATS
1553 				this_cpu_inc(stats->backtrack);
1554 #endif
1555 				/* Get Child's index */
1556 				pn = node_parent_rcu(pn);
1557 				cindex = get_index(pkey, pn);
1558 			}
1559 
1560 			/* strip the least significant bit from the cindex */
1561 			cindex &= cindex - 1;
1562 
1563 			/* grab pointer for next child node */
1564 			cptr = &pn->tnode[cindex];
1565 		}
1566 	}
1567 
1568 found:
1569 	/* this line carries forward the xor from earlier in the function */
1570 	index = key ^ n->key;
1571 
1572 	/* Step 3: Process the leaf, if that fails fall back to backtracing */
1573 	hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
1574 		struct fib_info *fi = fa->fa_info;
1575 		struct fib_nh_common *nhc;
1576 		int nhsel, err;
1577 
1578 		if ((BITS_PER_LONG > KEYLENGTH) || (fa->fa_slen < KEYLENGTH)) {
1579 			if (index >= (1ul << fa->fa_slen))
1580 				continue;
1581 		}
1582 		if (fa->fa_dscp &&
1583 		    inet_dscp_to_dsfield(fa->fa_dscp) != flp->flowi4_tos)
1584 			continue;
1585 		if (fi->fib_dead)
1586 			continue;
1587 		if (fa->fa_info->fib_scope < flp->flowi4_scope)
1588 			continue;
1589 		fib_alias_accessed(fa);
1590 		err = fib_props[fa->fa_type].error;
1591 		if (unlikely(err < 0)) {
1592 out_reject:
1593 #ifdef CONFIG_IP_FIB_TRIE_STATS
1594 			this_cpu_inc(stats->semantic_match_passed);
1595 #endif
1596 			trace_fib_table_lookup(tb->tb_id, flp, NULL, err);
1597 			return err;
1598 		}
1599 		if (fi->fib_flags & RTNH_F_DEAD)
1600 			continue;
1601 
1602 		if (unlikely(fi->nh)) {
1603 			if (nexthop_is_blackhole(fi->nh)) {
1604 				err = fib_props[RTN_BLACKHOLE].error;
1605 				goto out_reject;
1606 			}
1607 
1608 			nhc = nexthop_get_nhc_lookup(fi->nh, fib_flags, flp,
1609 						     &nhsel);
1610 			if (nhc)
1611 				goto set_result;
1612 			goto miss;
1613 		}
1614 
1615 		for (nhsel = 0; nhsel < fib_info_num_path(fi); nhsel++) {
1616 			nhc = fib_info_nhc(fi, nhsel);
1617 
1618 			if (!fib_lookup_good_nhc(nhc, fib_flags, flp))
1619 				continue;
1620 set_result:
1621 			if (!(fib_flags & FIB_LOOKUP_NOREF))
1622 				refcount_inc(&fi->fib_clntref);
1623 
1624 			res->prefix = htonl(n->key);
1625 			res->prefixlen = KEYLENGTH - fa->fa_slen;
1626 			res->nh_sel = nhsel;
1627 			res->nhc = nhc;
1628 			res->type = fa->fa_type;
1629 			res->scope = fi->fib_scope;
1630 			res->fi = fi;
1631 			res->table = tb;
1632 			res->fa_head = &n->leaf;
1633 #ifdef CONFIG_IP_FIB_TRIE_STATS
1634 			this_cpu_inc(stats->semantic_match_passed);
1635 #endif
1636 			trace_fib_table_lookup(tb->tb_id, flp, nhc, err);
1637 
1638 			return err;
1639 		}
1640 	}
1641 miss:
1642 #ifdef CONFIG_IP_FIB_TRIE_STATS
1643 	this_cpu_inc(stats->semantic_match_miss);
1644 #endif
1645 	goto backtrace;
1646 }
1647 EXPORT_SYMBOL_GPL(fib_table_lookup);
1648 
fib_remove_alias(struct trie * t,struct key_vector * tp,struct key_vector * l,struct fib_alias * old)1649 static void fib_remove_alias(struct trie *t, struct key_vector *tp,
1650 			     struct key_vector *l, struct fib_alias *old)
1651 {
1652 	/* record the location of the previous list_info entry */
1653 	struct hlist_node **pprev = old->fa_list.pprev;
1654 	struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
1655 
1656 	/* remove the fib_alias from the list */
1657 	hlist_del_rcu(&old->fa_list);
1658 
1659 	/* if we emptied the list this leaf will be freed and we can sort
1660 	 * out parent suffix lengths as a part of trie_rebalance
1661 	 */
1662 	if (hlist_empty(&l->leaf)) {
1663 		if (tp->slen == l->slen)
1664 			node_pull_suffix(tp, tp->pos);
1665 		put_child_root(tp, l->key, NULL);
1666 		node_free(l);
1667 		trie_rebalance(t, tp);
1668 		return;
1669 	}
1670 
1671 	/* only access fa if it is pointing at the last valid hlist_node */
1672 	if (*pprev)
1673 		return;
1674 
1675 	/* update the trie with the latest suffix length */
1676 	l->slen = fa->fa_slen;
1677 	node_pull_suffix(tp, fa->fa_slen);
1678 }
1679 
fib_notify_alias_delete(struct net * net,u32 key,struct hlist_head * fah,struct fib_alias * fa_to_delete,struct netlink_ext_ack * extack)1680 static void fib_notify_alias_delete(struct net *net, u32 key,
1681 				    struct hlist_head *fah,
1682 				    struct fib_alias *fa_to_delete,
1683 				    struct netlink_ext_ack *extack)
1684 {
1685 	struct fib_alias *fa_next, *fa_to_notify;
1686 	u32 tb_id = fa_to_delete->tb_id;
1687 	u8 slen = fa_to_delete->fa_slen;
1688 	enum fib_event_type fib_event;
1689 
1690 	/* Do not notify if we do not care about the route. */
1691 	if (fib_find_alias(fah, slen, 0, 0, tb_id, true) != fa_to_delete)
1692 		return;
1693 
1694 	/* Determine if the route should be replaced by the next route in the
1695 	 * list.
1696 	 */
1697 	fa_next = hlist_entry_safe(fa_to_delete->fa_list.next,
1698 				   struct fib_alias, fa_list);
1699 	if (fa_next && fa_next->fa_slen == slen && fa_next->tb_id == tb_id) {
1700 		fib_event = FIB_EVENT_ENTRY_REPLACE;
1701 		fa_to_notify = fa_next;
1702 	} else {
1703 		fib_event = FIB_EVENT_ENTRY_DEL;
1704 		fa_to_notify = fa_to_delete;
1705 	}
1706 	call_fib_entry_notifiers(net, fib_event, key, KEYLENGTH - slen,
1707 				 fa_to_notify, extack);
1708 }
1709 
1710 /* Caller must hold RTNL. */
fib_table_delete(struct net * net,struct fib_table * tb,struct fib_config * cfg,struct netlink_ext_ack * extack)1711 int fib_table_delete(struct net *net, struct fib_table *tb,
1712 		     struct fib_config *cfg, struct netlink_ext_ack *extack)
1713 {
1714 	struct trie *t = (struct trie *) tb->tb_data;
1715 	struct fib_alias *fa, *fa_to_delete;
1716 	struct key_vector *l, *tp;
1717 	u8 plen = cfg->fc_dst_len;
1718 	u8 slen = KEYLENGTH - plen;
1719 	dscp_t dscp;
1720 	u32 key;
1721 
1722 	key = ntohl(cfg->fc_dst);
1723 
1724 	if (!fib_valid_key_len(key, plen, extack))
1725 		return -EINVAL;
1726 
1727 	l = fib_find_node(t, &tp, key);
1728 	if (!l)
1729 		return -ESRCH;
1730 
1731 	dscp = cfg->fc_dscp;
1732 	fa = fib_find_alias(&l->leaf, slen, dscp, 0, tb->tb_id, false);
1733 	if (!fa)
1734 		return -ESRCH;
1735 
1736 	pr_debug("Deleting %08x/%d dsfield=0x%02x t=%p\n", key, plen,
1737 		 inet_dscp_to_dsfield(dscp), t);
1738 
1739 	fa_to_delete = NULL;
1740 	hlist_for_each_entry_from(fa, fa_list) {
1741 		struct fib_info *fi = fa->fa_info;
1742 
1743 		if ((fa->fa_slen != slen) ||
1744 		    (fa->tb_id != tb->tb_id) ||
1745 		    (fa->fa_dscp != dscp))
1746 			break;
1747 
1748 		if ((!cfg->fc_type || fa->fa_type == cfg->fc_type) &&
1749 		    (cfg->fc_scope == RT_SCOPE_NOWHERE ||
1750 		     fa->fa_info->fib_scope == cfg->fc_scope) &&
1751 		    (!cfg->fc_prefsrc ||
1752 		     fi->fib_prefsrc == cfg->fc_prefsrc) &&
1753 		    (!cfg->fc_protocol ||
1754 		     fi->fib_protocol == cfg->fc_protocol) &&
1755 		    fib_nh_match(net, cfg, fi, extack) == 0 &&
1756 		    fib_metrics_match(cfg, fi)) {
1757 			fa_to_delete = fa;
1758 			break;
1759 		}
1760 	}
1761 
1762 	if (!fa_to_delete)
1763 		return -ESRCH;
1764 
1765 	fib_notify_alias_delete(net, key, &l->leaf, fa_to_delete, extack);
1766 	rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
1767 		  &cfg->fc_nlinfo, 0);
1768 
1769 	if (!plen)
1770 		tb->tb_num_default--;
1771 
1772 	fib_remove_alias(t, tp, l, fa_to_delete);
1773 
1774 	if (fa_to_delete->fa_state & FA_S_ACCESSED)
1775 		rt_cache_flush(cfg->fc_nlinfo.nl_net);
1776 
1777 	fib_release_info(fa_to_delete->fa_info);
1778 	alias_free_mem_rcu(fa_to_delete);
1779 	return 0;
1780 }
1781 
1782 /* Scan for the next leaf starting at the provided key value */
leaf_walk_rcu(struct key_vector ** tn,t_key key)1783 static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
1784 {
1785 	struct key_vector *pn, *n = *tn;
1786 	unsigned long cindex;
1787 
1788 	/* this loop is meant to try and find the key in the trie */
1789 	do {
1790 		/* record parent and next child index */
1791 		pn = n;
1792 		cindex = (key > pn->key) ? get_index(key, pn) : 0;
1793 
1794 		if (cindex >> pn->bits)
1795 			break;
1796 
1797 		/* descend into the next child */
1798 		n = get_child_rcu(pn, cindex++);
1799 		if (!n)
1800 			break;
1801 
1802 		/* guarantee forward progress on the keys */
1803 		if (IS_LEAF(n) && (n->key >= key))
1804 			goto found;
1805 	} while (IS_TNODE(n));
1806 
1807 	/* this loop will search for the next leaf with a greater key */
1808 	while (!IS_TRIE(pn)) {
1809 		/* if we exhausted the parent node we will need to climb */
1810 		if (cindex >= (1ul << pn->bits)) {
1811 			t_key pkey = pn->key;
1812 
1813 			pn = node_parent_rcu(pn);
1814 			cindex = get_index(pkey, pn) + 1;
1815 			continue;
1816 		}
1817 
1818 		/* grab the next available node */
1819 		n = get_child_rcu(pn, cindex++);
1820 		if (!n)
1821 			continue;
1822 
1823 		/* no need to compare keys since we bumped the index */
1824 		if (IS_LEAF(n))
1825 			goto found;
1826 
1827 		/* Rescan start scanning in new node */
1828 		pn = n;
1829 		cindex = 0;
1830 	}
1831 
1832 	*tn = pn;
1833 	return NULL; /* Root of trie */
1834 found:
1835 	/* if we are at the limit for keys just return NULL for the tnode */
1836 	*tn = pn;
1837 	return n;
1838 }
1839 
fib_trie_free(struct fib_table * tb)1840 static void fib_trie_free(struct fib_table *tb)
1841 {
1842 	struct trie *t = (struct trie *)tb->tb_data;
1843 	struct key_vector *pn = t->kv;
1844 	unsigned long cindex = 1;
1845 	struct hlist_node *tmp;
1846 	struct fib_alias *fa;
1847 
1848 	/* walk trie in reverse order and free everything */
1849 	for (;;) {
1850 		struct key_vector *n;
1851 
1852 		if (!(cindex--)) {
1853 			t_key pkey = pn->key;
1854 
1855 			if (IS_TRIE(pn))
1856 				break;
1857 
1858 			n = pn;
1859 			pn = node_parent(pn);
1860 
1861 			/* drop emptied tnode */
1862 			put_child_root(pn, n->key, NULL);
1863 			node_free(n);
1864 
1865 			cindex = get_index(pkey, pn);
1866 
1867 			continue;
1868 		}
1869 
1870 		/* grab the next available node */
1871 		n = get_child(pn, cindex);
1872 		if (!n)
1873 			continue;
1874 
1875 		if (IS_TNODE(n)) {
1876 			/* record pn and cindex for leaf walking */
1877 			pn = n;
1878 			cindex = 1ul << n->bits;
1879 
1880 			continue;
1881 		}
1882 
1883 		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
1884 			hlist_del_rcu(&fa->fa_list);
1885 			alias_free_mem_rcu(fa);
1886 		}
1887 
1888 		put_child_root(pn, n->key, NULL);
1889 		node_free(n);
1890 	}
1891 
1892 #ifdef CONFIG_IP_FIB_TRIE_STATS
1893 	free_percpu(t->stats);
1894 #endif
1895 	kfree(tb);
1896 }
1897 
fib_trie_unmerge(struct fib_table * oldtb)1898 struct fib_table *fib_trie_unmerge(struct fib_table *oldtb)
1899 {
1900 	struct trie *ot = (struct trie *)oldtb->tb_data;
1901 	struct key_vector *l, *tp = ot->kv;
1902 	struct fib_table *local_tb;
1903 	struct fib_alias *fa;
1904 	struct trie *lt;
1905 	t_key key = 0;
1906 
1907 	if (oldtb->tb_data == oldtb->__data)
1908 		return oldtb;
1909 
1910 	local_tb = fib_trie_table(RT_TABLE_LOCAL, NULL);
1911 	if (!local_tb)
1912 		return NULL;
1913 
1914 	lt = (struct trie *)local_tb->tb_data;
1915 
1916 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
1917 		struct key_vector *local_l = NULL, *local_tp;
1918 
1919 		hlist_for_each_entry(fa, &l->leaf, fa_list) {
1920 			struct fib_alias *new_fa;
1921 
1922 			if (local_tb->tb_id != fa->tb_id)
1923 				continue;
1924 
1925 			/* clone fa for new local table */
1926 			new_fa = kmem_cache_alloc(fn_alias_kmem, GFP_KERNEL);
1927 			if (!new_fa)
1928 				goto out;
1929 
1930 			memcpy(new_fa, fa, sizeof(*fa));
1931 
1932 			/* insert clone into table */
1933 			if (!local_l)
1934 				local_l = fib_find_node(lt, &local_tp, l->key);
1935 
1936 			if (fib_insert_alias(lt, local_tp, local_l, new_fa,
1937 					     NULL, l->key)) {
1938 				kmem_cache_free(fn_alias_kmem, new_fa);
1939 				goto out;
1940 			}
1941 		}
1942 
1943 		/* stop loop if key wrapped back to 0 */
1944 		key = l->key + 1;
1945 		if (key < l->key)
1946 			break;
1947 	}
1948 
1949 	return local_tb;
1950 out:
1951 	fib_trie_free(local_tb);
1952 
1953 	return NULL;
1954 }
1955 
1956 /* Caller must hold RTNL */
fib_table_flush_external(struct fib_table * tb)1957 void fib_table_flush_external(struct fib_table *tb)
1958 {
1959 	struct trie *t = (struct trie *)tb->tb_data;
1960 	struct key_vector *pn = t->kv;
1961 	unsigned long cindex = 1;
1962 	struct hlist_node *tmp;
1963 	struct fib_alias *fa;
1964 
1965 	/* walk trie in reverse order */
1966 	for (;;) {
1967 		unsigned char slen = 0;
1968 		struct key_vector *n;
1969 
1970 		if (!(cindex--)) {
1971 			t_key pkey = pn->key;
1972 
1973 			/* cannot resize the trie vector */
1974 			if (IS_TRIE(pn))
1975 				break;
1976 
1977 			/* update the suffix to address pulled leaves */
1978 			if (pn->slen > pn->pos)
1979 				update_suffix(pn);
1980 
1981 			/* resize completed node */
1982 			pn = resize(t, pn);
1983 			cindex = get_index(pkey, pn);
1984 
1985 			continue;
1986 		}
1987 
1988 		/* grab the next available node */
1989 		n = get_child(pn, cindex);
1990 		if (!n)
1991 			continue;
1992 
1993 		if (IS_TNODE(n)) {
1994 			/* record pn and cindex for leaf walking */
1995 			pn = n;
1996 			cindex = 1ul << n->bits;
1997 
1998 			continue;
1999 		}
2000 
2001 		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
2002 			/* if alias was cloned to local then we just
2003 			 * need to remove the local copy from main
2004 			 */
2005 			if (tb->tb_id != fa->tb_id) {
2006 				hlist_del_rcu(&fa->fa_list);
2007 				alias_free_mem_rcu(fa);
2008 				continue;
2009 			}
2010 
2011 			/* record local slen */
2012 			slen = fa->fa_slen;
2013 		}
2014 
2015 		/* update leaf slen */
2016 		n->slen = slen;
2017 
2018 		if (hlist_empty(&n->leaf)) {
2019 			put_child_root(pn, n->key, NULL);
2020 			node_free(n);
2021 		}
2022 	}
2023 }
2024 
2025 /* Caller must hold RTNL. */
fib_table_flush(struct net * net,struct fib_table * tb,bool flush_all)2026 int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
2027 {
2028 	struct trie *t = (struct trie *)tb->tb_data;
2029 	struct key_vector *pn = t->kv;
2030 	unsigned long cindex = 1;
2031 	struct hlist_node *tmp;
2032 	struct fib_alias *fa;
2033 	int found = 0;
2034 
2035 	/* walk trie in reverse order */
2036 	for (;;) {
2037 		unsigned char slen = 0;
2038 		struct key_vector *n;
2039 
2040 		if (!(cindex--)) {
2041 			t_key pkey = pn->key;
2042 
2043 			/* cannot resize the trie vector */
2044 			if (IS_TRIE(pn))
2045 				break;
2046 
2047 			/* update the suffix to address pulled leaves */
2048 			if (pn->slen > pn->pos)
2049 				update_suffix(pn);
2050 
2051 			/* resize completed node */
2052 			pn = resize(t, pn);
2053 			cindex = get_index(pkey, pn);
2054 
2055 			continue;
2056 		}
2057 
2058 		/* grab the next available node */
2059 		n = get_child(pn, cindex);
2060 		if (!n)
2061 			continue;
2062 
2063 		if (IS_TNODE(n)) {
2064 			/* record pn and cindex for leaf walking */
2065 			pn = n;
2066 			cindex = 1ul << n->bits;
2067 
2068 			continue;
2069 		}
2070 
2071 		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
2072 			struct fib_info *fi = fa->fa_info;
2073 
2074 			if (!fi || tb->tb_id != fa->tb_id ||
2075 			    (!(fi->fib_flags & RTNH_F_DEAD) &&
2076 			     !fib_props[fa->fa_type].error)) {
2077 				slen = fa->fa_slen;
2078 				continue;
2079 			}
2080 
2081 			/* Do not flush error routes if network namespace is
2082 			 * not being dismantled
2083 			 */
2084 			if (!flush_all && fib_props[fa->fa_type].error) {
2085 				slen = fa->fa_slen;
2086 				continue;
2087 			}
2088 
2089 			fib_notify_alias_delete(net, n->key, &n->leaf, fa,
2090 						NULL);
2091 			hlist_del_rcu(&fa->fa_list);
2092 			fib_release_info(fa->fa_info);
2093 			alias_free_mem_rcu(fa);
2094 			found++;
2095 		}
2096 
2097 		/* update leaf slen */
2098 		n->slen = slen;
2099 
2100 		if (hlist_empty(&n->leaf)) {
2101 			put_child_root(pn, n->key, NULL);
2102 			node_free(n);
2103 		}
2104 	}
2105 
2106 	pr_debug("trie_flush found=%d\n", found);
2107 	return found;
2108 }
2109 
2110 /* derived from fib_trie_free */
__fib_info_notify_update(struct net * net,struct fib_table * tb,struct nl_info * info)2111 static void __fib_info_notify_update(struct net *net, struct fib_table *tb,
2112 				     struct nl_info *info)
2113 {
2114 	struct trie *t = (struct trie *)tb->tb_data;
2115 	struct key_vector *pn = t->kv;
2116 	unsigned long cindex = 1;
2117 	struct fib_alias *fa;
2118 
2119 	for (;;) {
2120 		struct key_vector *n;
2121 
2122 		if (!(cindex--)) {
2123 			t_key pkey = pn->key;
2124 
2125 			if (IS_TRIE(pn))
2126 				break;
2127 
2128 			pn = node_parent(pn);
2129 			cindex = get_index(pkey, pn);
2130 			continue;
2131 		}
2132 
2133 		/* grab the next available node */
2134 		n = get_child(pn, cindex);
2135 		if (!n)
2136 			continue;
2137 
2138 		if (IS_TNODE(n)) {
2139 			/* record pn and cindex for leaf walking */
2140 			pn = n;
2141 			cindex = 1ul << n->bits;
2142 
2143 			continue;
2144 		}
2145 
2146 		hlist_for_each_entry(fa, &n->leaf, fa_list) {
2147 			struct fib_info *fi = fa->fa_info;
2148 
2149 			if (!fi || !fi->nh_updated || fa->tb_id != tb->tb_id)
2150 				continue;
2151 
2152 			rtmsg_fib(RTM_NEWROUTE, htonl(n->key), fa,
2153 				  KEYLENGTH - fa->fa_slen, tb->tb_id,
2154 				  info, NLM_F_REPLACE);
2155 		}
2156 	}
2157 }
2158 
fib_info_notify_update(struct net * net,struct nl_info * info)2159 void fib_info_notify_update(struct net *net, struct nl_info *info)
2160 {
2161 	unsigned int h;
2162 
2163 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2164 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2165 		struct fib_table *tb;
2166 
2167 		hlist_for_each_entry_rcu(tb, head, tb_hlist,
2168 					 lockdep_rtnl_is_held())
2169 			__fib_info_notify_update(net, tb, info);
2170 	}
2171 }
2172 
fib_leaf_notify(struct key_vector * l,struct fib_table * tb,struct notifier_block * nb,struct netlink_ext_ack * extack)2173 static int fib_leaf_notify(struct key_vector *l, struct fib_table *tb,
2174 			   struct notifier_block *nb,
2175 			   struct netlink_ext_ack *extack)
2176 {
2177 	struct fib_alias *fa;
2178 	int last_slen = -1;
2179 	int err;
2180 
2181 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2182 		struct fib_info *fi = fa->fa_info;
2183 
2184 		if (!fi)
2185 			continue;
2186 
2187 		/* local and main table can share the same trie,
2188 		 * so don't notify twice for the same entry.
2189 		 */
2190 		if (tb->tb_id != fa->tb_id)
2191 			continue;
2192 
2193 		if (fa->fa_slen == last_slen)
2194 			continue;
2195 
2196 		last_slen = fa->fa_slen;
2197 		err = call_fib_entry_notifier(nb, FIB_EVENT_ENTRY_REPLACE,
2198 					      l->key, KEYLENGTH - fa->fa_slen,
2199 					      fa, extack);
2200 		if (err)
2201 			return err;
2202 	}
2203 	return 0;
2204 }
2205 
fib_table_notify(struct fib_table * tb,struct notifier_block * nb,struct netlink_ext_ack * extack)2206 static int fib_table_notify(struct fib_table *tb, struct notifier_block *nb,
2207 			    struct netlink_ext_ack *extack)
2208 {
2209 	struct trie *t = (struct trie *)tb->tb_data;
2210 	struct key_vector *l, *tp = t->kv;
2211 	t_key key = 0;
2212 	int err;
2213 
2214 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2215 		err = fib_leaf_notify(l, tb, nb, extack);
2216 		if (err)
2217 			return err;
2218 
2219 		key = l->key + 1;
2220 		/* stop in case of wrap around */
2221 		if (key < l->key)
2222 			break;
2223 	}
2224 	return 0;
2225 }
2226 
fib_notify(struct net * net,struct notifier_block * nb,struct netlink_ext_ack * extack)2227 int fib_notify(struct net *net, struct notifier_block *nb,
2228 	       struct netlink_ext_ack *extack)
2229 {
2230 	unsigned int h;
2231 	int err;
2232 
2233 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2234 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2235 		struct fib_table *tb;
2236 
2237 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2238 			err = fib_table_notify(tb, nb, extack);
2239 			if (err)
2240 				return err;
2241 		}
2242 	}
2243 	return 0;
2244 }
2245 
__trie_free_rcu(struct rcu_head * head)2246 static void __trie_free_rcu(struct rcu_head *head)
2247 {
2248 	struct fib_table *tb = container_of(head, struct fib_table, rcu);
2249 #ifdef CONFIG_IP_FIB_TRIE_STATS
2250 	struct trie *t = (struct trie *)tb->tb_data;
2251 
2252 	if (tb->tb_data == tb->__data)
2253 		free_percpu(t->stats);
2254 #endif /* CONFIG_IP_FIB_TRIE_STATS */
2255 	kfree(tb);
2256 }
2257 
fib_free_table(struct fib_table * tb)2258 void fib_free_table(struct fib_table *tb)
2259 {
2260 	call_rcu(&tb->rcu, __trie_free_rcu);
2261 }
2262 
fn_trie_dump_leaf(struct key_vector * l,struct fib_table * tb,struct sk_buff * skb,struct netlink_callback * cb,struct fib_dump_filter * filter)2263 static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
2264 			     struct sk_buff *skb, struct netlink_callback *cb,
2265 			     struct fib_dump_filter *filter)
2266 {
2267 	unsigned int flags = NLM_F_MULTI;
2268 	__be32 xkey = htonl(l->key);
2269 	int i, s_i, i_fa, s_fa, err;
2270 	struct fib_alias *fa;
2271 
2272 	if (filter->filter_set ||
2273 	    !filter->dump_exceptions || !filter->dump_routes)
2274 		flags |= NLM_F_DUMP_FILTERED;
2275 
2276 	s_i = cb->args[4];
2277 	s_fa = cb->args[5];
2278 	i = 0;
2279 
2280 	/* rcu_read_lock is hold by caller */
2281 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2282 		struct fib_info *fi = fa->fa_info;
2283 
2284 		if (i < s_i)
2285 			goto next;
2286 
2287 		i_fa = 0;
2288 
2289 		if (tb->tb_id != fa->tb_id)
2290 			goto next;
2291 
2292 		if (filter->filter_set) {
2293 			if (filter->rt_type && fa->fa_type != filter->rt_type)
2294 				goto next;
2295 
2296 			if ((filter->protocol &&
2297 			     fi->fib_protocol != filter->protocol))
2298 				goto next;
2299 
2300 			if (filter->dev &&
2301 			    !fib_info_nh_uses_dev(fi, filter->dev))
2302 				goto next;
2303 		}
2304 
2305 		if (filter->dump_routes) {
2306 			if (!s_fa) {
2307 				struct fib_rt_info fri;
2308 
2309 				fri.fi = fi;
2310 				fri.tb_id = tb->tb_id;
2311 				fri.dst = xkey;
2312 				fri.dst_len = KEYLENGTH - fa->fa_slen;
2313 				fri.dscp = fa->fa_dscp;
2314 				fri.type = fa->fa_type;
2315 				fri.offload = READ_ONCE(fa->offload);
2316 				fri.trap = READ_ONCE(fa->trap);
2317 				fri.offload_failed = READ_ONCE(fa->offload_failed);
2318 				err = fib_dump_info(skb,
2319 						    NETLINK_CB(cb->skb).portid,
2320 						    cb->nlh->nlmsg_seq,
2321 						    RTM_NEWROUTE, &fri, flags);
2322 				if (err < 0)
2323 					goto stop;
2324 			}
2325 
2326 			i_fa++;
2327 		}
2328 
2329 		if (filter->dump_exceptions) {
2330 			err = fib_dump_info_fnhe(skb, cb, tb->tb_id, fi,
2331 						 &i_fa, s_fa, flags);
2332 			if (err < 0)
2333 				goto stop;
2334 		}
2335 
2336 next:
2337 		i++;
2338 	}
2339 
2340 	cb->args[4] = i;
2341 	return skb->len;
2342 
2343 stop:
2344 	cb->args[4] = i;
2345 	cb->args[5] = i_fa;
2346 	return err;
2347 }
2348 
2349 /* rcu_read_lock needs to be hold by caller from readside */
fib_table_dump(struct fib_table * tb,struct sk_buff * skb,struct netlink_callback * cb,struct fib_dump_filter * filter)2350 int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
2351 		   struct netlink_callback *cb, struct fib_dump_filter *filter)
2352 {
2353 	struct trie *t = (struct trie *)tb->tb_data;
2354 	struct key_vector *l, *tp = t->kv;
2355 	/* Dump starting at last key.
2356 	 * Note: 0.0.0.0/0 (ie default) is first key.
2357 	 */
2358 	int count = cb->args[2];
2359 	t_key key = cb->args[3];
2360 
2361 	/* First time here, count and key are both always 0. Count > 0
2362 	 * and key == 0 means the dump has wrapped around and we are done.
2363 	 */
2364 	if (count && !key)
2365 		return skb->len;
2366 
2367 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
2368 		int err;
2369 
2370 		err = fn_trie_dump_leaf(l, tb, skb, cb, filter);
2371 		if (err < 0) {
2372 			cb->args[3] = key;
2373 			cb->args[2] = count;
2374 			return err;
2375 		}
2376 
2377 		++count;
2378 		key = l->key + 1;
2379 
2380 		memset(&cb->args[4], 0,
2381 		       sizeof(cb->args) - 4*sizeof(cb->args[0]));
2382 
2383 		/* stop loop if key wrapped back to 0 */
2384 		if (key < l->key)
2385 			break;
2386 	}
2387 
2388 	cb->args[3] = key;
2389 	cb->args[2] = count;
2390 
2391 	return skb->len;
2392 }
2393 
fib_trie_init(void)2394 void __init fib_trie_init(void)
2395 {
2396 	fn_alias_kmem = kmem_cache_create("ip_fib_alias",
2397 					  sizeof(struct fib_alias),
2398 					  0, SLAB_PANIC | SLAB_ACCOUNT, NULL);
2399 
2400 	trie_leaf_kmem = kmem_cache_create("ip_fib_trie",
2401 					   LEAF_SIZE,
2402 					   0, SLAB_PANIC | SLAB_ACCOUNT, NULL);
2403 }
2404 
fib_trie_table(u32 id,struct fib_table * alias)2405 struct fib_table *fib_trie_table(u32 id, struct fib_table *alias)
2406 {
2407 	struct fib_table *tb;
2408 	struct trie *t;
2409 	size_t sz = sizeof(*tb);
2410 
2411 	if (!alias)
2412 		sz += sizeof(struct trie);
2413 
2414 	tb = kzalloc(sz, GFP_KERNEL);
2415 	if (!tb)
2416 		return NULL;
2417 
2418 	tb->tb_id = id;
2419 	tb->tb_num_default = 0;
2420 	tb->tb_data = (alias ? alias->__data : tb->__data);
2421 
2422 	if (alias)
2423 		return tb;
2424 
2425 	t = (struct trie *) tb->tb_data;
2426 	t->kv[0].pos = KEYLENGTH;
2427 	t->kv[0].slen = KEYLENGTH;
2428 #ifdef CONFIG_IP_FIB_TRIE_STATS
2429 	t->stats = alloc_percpu(struct trie_use_stats);
2430 	if (!t->stats) {
2431 		kfree(tb);
2432 		tb = NULL;
2433 	}
2434 #endif
2435 
2436 	return tb;
2437 }
2438 
2439 #ifdef CONFIG_PROC_FS
2440 /* Depth first Trie walk iterator */
2441 struct fib_trie_iter {
2442 	struct seq_net_private p;
2443 	struct fib_table *tb;
2444 	struct key_vector *tnode;
2445 	unsigned int index;
2446 	unsigned int depth;
2447 };
2448 
fib_trie_get_next(struct fib_trie_iter * iter)2449 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
2450 {
2451 	unsigned long cindex = iter->index;
2452 	struct key_vector *pn = iter->tnode;
2453 	t_key pkey;
2454 
2455 	pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
2456 		 iter->tnode, iter->index, iter->depth);
2457 
2458 	while (!IS_TRIE(pn)) {
2459 		while (cindex < child_length(pn)) {
2460 			struct key_vector *n = get_child_rcu(pn, cindex++);
2461 
2462 			if (!n)
2463 				continue;
2464 
2465 			if (IS_LEAF(n)) {
2466 				iter->tnode = pn;
2467 				iter->index = cindex;
2468 			} else {
2469 				/* push down one level */
2470 				iter->tnode = n;
2471 				iter->index = 0;
2472 				++iter->depth;
2473 			}
2474 
2475 			return n;
2476 		}
2477 
2478 		/* Current node exhausted, pop back up */
2479 		pkey = pn->key;
2480 		pn = node_parent_rcu(pn);
2481 		cindex = get_index(pkey, pn) + 1;
2482 		--iter->depth;
2483 	}
2484 
2485 	/* record root node so further searches know we are done */
2486 	iter->tnode = pn;
2487 	iter->index = 0;
2488 
2489 	return NULL;
2490 }
2491 
fib_trie_get_first(struct fib_trie_iter * iter,struct trie * t)2492 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
2493 					     struct trie *t)
2494 {
2495 	struct key_vector *n, *pn;
2496 
2497 	if (!t)
2498 		return NULL;
2499 
2500 	pn = t->kv;
2501 	n = rcu_dereference(pn->tnode[0]);
2502 	if (!n)
2503 		return NULL;
2504 
2505 	if (IS_TNODE(n)) {
2506 		iter->tnode = n;
2507 		iter->index = 0;
2508 		iter->depth = 1;
2509 	} else {
2510 		iter->tnode = pn;
2511 		iter->index = 0;
2512 		iter->depth = 0;
2513 	}
2514 
2515 	return n;
2516 }
2517 
trie_collect_stats(struct trie * t,struct trie_stat * s)2518 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
2519 {
2520 	struct key_vector *n;
2521 	struct fib_trie_iter iter;
2522 
2523 	memset(s, 0, sizeof(*s));
2524 
2525 	rcu_read_lock();
2526 	for (n = fib_trie_get_first(&iter, t); n; n = fib_trie_get_next(&iter)) {
2527 		if (IS_LEAF(n)) {
2528 			struct fib_alias *fa;
2529 
2530 			s->leaves++;
2531 			s->totdepth += iter.depth;
2532 			if (iter.depth > s->maxdepth)
2533 				s->maxdepth = iter.depth;
2534 
2535 			hlist_for_each_entry_rcu(fa, &n->leaf, fa_list)
2536 				++s->prefixes;
2537 		} else {
2538 			s->tnodes++;
2539 			if (n->bits < MAX_STAT_DEPTH)
2540 				s->nodesizes[n->bits]++;
2541 			s->nullpointers += tn_info(n)->empty_children;
2542 		}
2543 	}
2544 	rcu_read_unlock();
2545 }
2546 
2547 /*
2548  *	This outputs /proc/net/fib_triestats
2549  */
trie_show_stats(struct seq_file * seq,struct trie_stat * stat)2550 static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
2551 {
2552 	unsigned int i, max, pointers, bytes, avdepth;
2553 
2554 	if (stat->leaves)
2555 		avdepth = stat->totdepth*100 / stat->leaves;
2556 	else
2557 		avdepth = 0;
2558 
2559 	seq_printf(seq, "\tAver depth:     %u.%02d\n",
2560 		   avdepth / 100, avdepth % 100);
2561 	seq_printf(seq, "\tMax depth:      %u\n", stat->maxdepth);
2562 
2563 	seq_printf(seq, "\tLeaves:         %u\n", stat->leaves);
2564 	bytes = LEAF_SIZE * stat->leaves;
2565 
2566 	seq_printf(seq, "\tPrefixes:       %u\n", stat->prefixes);
2567 	bytes += sizeof(struct fib_alias) * stat->prefixes;
2568 
2569 	seq_printf(seq, "\tInternal nodes: %u\n\t", stat->tnodes);
2570 	bytes += TNODE_SIZE(0) * stat->tnodes;
2571 
2572 	max = MAX_STAT_DEPTH;
2573 	while (max > 0 && stat->nodesizes[max-1] == 0)
2574 		max--;
2575 
2576 	pointers = 0;
2577 	for (i = 1; i < max; i++)
2578 		if (stat->nodesizes[i] != 0) {
2579 			seq_printf(seq, "  %u: %u",  i, stat->nodesizes[i]);
2580 			pointers += (1<<i) * stat->nodesizes[i];
2581 		}
2582 	seq_putc(seq, '\n');
2583 	seq_printf(seq, "\tPointers: %u\n", pointers);
2584 
2585 	bytes += sizeof(struct key_vector *) * pointers;
2586 	seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
2587 	seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
2588 }
2589 
2590 #ifdef CONFIG_IP_FIB_TRIE_STATS
trie_show_usage(struct seq_file * seq,const struct trie_use_stats __percpu * stats)2591 static void trie_show_usage(struct seq_file *seq,
2592 			    const struct trie_use_stats __percpu *stats)
2593 {
2594 	struct trie_use_stats s = { 0 };
2595 	int cpu;
2596 
2597 	/* loop through all of the CPUs and gather up the stats */
2598 	for_each_possible_cpu(cpu) {
2599 		const struct trie_use_stats *pcpu = per_cpu_ptr(stats, cpu);
2600 
2601 		s.gets += pcpu->gets;
2602 		s.backtrack += pcpu->backtrack;
2603 		s.semantic_match_passed += pcpu->semantic_match_passed;
2604 		s.semantic_match_miss += pcpu->semantic_match_miss;
2605 		s.null_node_hit += pcpu->null_node_hit;
2606 		s.resize_node_skipped += pcpu->resize_node_skipped;
2607 	}
2608 
2609 	seq_printf(seq, "\nCounters:\n---------\n");
2610 	seq_printf(seq, "gets = %u\n", s.gets);
2611 	seq_printf(seq, "backtracks = %u\n", s.backtrack);
2612 	seq_printf(seq, "semantic match passed = %u\n",
2613 		   s.semantic_match_passed);
2614 	seq_printf(seq, "semantic match miss = %u\n", s.semantic_match_miss);
2615 	seq_printf(seq, "null node hit= %u\n", s.null_node_hit);
2616 	seq_printf(seq, "skipped node resize = %u\n\n", s.resize_node_skipped);
2617 }
2618 #endif /*  CONFIG_IP_FIB_TRIE_STATS */
2619 
fib_table_print(struct seq_file * seq,struct fib_table * tb)2620 static void fib_table_print(struct seq_file *seq, struct fib_table *tb)
2621 {
2622 	if (tb->tb_id == RT_TABLE_LOCAL)
2623 		seq_puts(seq, "Local:\n");
2624 	else if (tb->tb_id == RT_TABLE_MAIN)
2625 		seq_puts(seq, "Main:\n");
2626 	else
2627 		seq_printf(seq, "Id %d:\n", tb->tb_id);
2628 }
2629 
2630 
fib_triestat_seq_show(struct seq_file * seq,void * v)2631 static int fib_triestat_seq_show(struct seq_file *seq, void *v)
2632 {
2633 	struct net *net = seq->private;
2634 	unsigned int h;
2635 
2636 	seq_printf(seq,
2637 		   "Basic info: size of leaf:"
2638 		   " %zd bytes, size of tnode: %zd bytes.\n",
2639 		   LEAF_SIZE, TNODE_SIZE(0));
2640 
2641 	rcu_read_lock();
2642 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2643 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2644 		struct fib_table *tb;
2645 
2646 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2647 			struct trie *t = (struct trie *) tb->tb_data;
2648 			struct trie_stat stat;
2649 
2650 			if (!t)
2651 				continue;
2652 
2653 			fib_table_print(seq, tb);
2654 
2655 			trie_collect_stats(t, &stat);
2656 			trie_show_stats(seq, &stat);
2657 #ifdef CONFIG_IP_FIB_TRIE_STATS
2658 			trie_show_usage(seq, t->stats);
2659 #endif
2660 		}
2661 		cond_resched_rcu();
2662 	}
2663 	rcu_read_unlock();
2664 
2665 	return 0;
2666 }
2667 
fib_trie_get_idx(struct seq_file * seq,loff_t pos)2668 static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
2669 {
2670 	struct fib_trie_iter *iter = seq->private;
2671 	struct net *net = seq_file_net(seq);
2672 	loff_t idx = 0;
2673 	unsigned int h;
2674 
2675 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {
2676 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2677 		struct fib_table *tb;
2678 
2679 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2680 			struct key_vector *n;
2681 
2682 			for (n = fib_trie_get_first(iter,
2683 						    (struct trie *) tb->tb_data);
2684 			     n; n = fib_trie_get_next(iter))
2685 				if (pos == idx++) {
2686 					iter->tb = tb;
2687 					return n;
2688 				}
2689 		}
2690 	}
2691 
2692 	return NULL;
2693 }
2694 
fib_trie_seq_start(struct seq_file * seq,loff_t * pos)2695 static void *fib_trie_seq_start(struct seq_file *seq, loff_t *pos)
2696 	__acquires(RCU)
2697 {
2698 	rcu_read_lock();
2699 	return fib_trie_get_idx(seq, *pos);
2700 }
2701 
fib_trie_seq_next(struct seq_file * seq,void * v,loff_t * pos)2702 static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2703 {
2704 	struct fib_trie_iter *iter = seq->private;
2705 	struct net *net = seq_file_net(seq);
2706 	struct fib_table *tb = iter->tb;
2707 	struct hlist_node *tb_node;
2708 	unsigned int h;
2709 	struct key_vector *n;
2710 
2711 	++*pos;
2712 	/* next node in same table */
2713 	n = fib_trie_get_next(iter);
2714 	if (n)
2715 		return n;
2716 
2717 	/* walk rest of this hash chain */
2718 	h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
2719 	while ((tb_node = rcu_dereference(hlist_next_rcu(&tb->tb_hlist)))) {
2720 		tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
2721 		n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2722 		if (n)
2723 			goto found;
2724 	}
2725 
2726 	/* new hash chain */
2727 	while (++h < FIB_TABLE_HASHSZ) {
2728 		struct hlist_head *head = &net->ipv4.fib_table_hash[h];
2729 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
2730 			n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
2731 			if (n)
2732 				goto found;
2733 		}
2734 	}
2735 	return NULL;
2736 
2737 found:
2738 	iter->tb = tb;
2739 	return n;
2740 }
2741 
fib_trie_seq_stop(struct seq_file * seq,void * v)2742 static void fib_trie_seq_stop(struct seq_file *seq, void *v)
2743 	__releases(RCU)
2744 {
2745 	rcu_read_unlock();
2746 }
2747 
seq_indent(struct seq_file * seq,int n)2748 static void seq_indent(struct seq_file *seq, int n)
2749 {
2750 	while (n-- > 0)
2751 		seq_puts(seq, "   ");
2752 }
2753 
rtn_scope(char * buf,size_t len,enum rt_scope_t s)2754 static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
2755 {
2756 	switch (s) {
2757 	case RT_SCOPE_UNIVERSE: return "universe";
2758 	case RT_SCOPE_SITE:	return "site";
2759 	case RT_SCOPE_LINK:	return "link";
2760 	case RT_SCOPE_HOST:	return "host";
2761 	case RT_SCOPE_NOWHERE:	return "nowhere";
2762 	default:
2763 		snprintf(buf, len, "scope=%d", s);
2764 		return buf;
2765 	}
2766 }
2767 
2768 static const char *const rtn_type_names[__RTN_MAX] = {
2769 	[RTN_UNSPEC] = "UNSPEC",
2770 	[RTN_UNICAST] = "UNICAST",
2771 	[RTN_LOCAL] = "LOCAL",
2772 	[RTN_BROADCAST] = "BROADCAST",
2773 	[RTN_ANYCAST] = "ANYCAST",
2774 	[RTN_MULTICAST] = "MULTICAST",
2775 	[RTN_BLACKHOLE] = "BLACKHOLE",
2776 	[RTN_UNREACHABLE] = "UNREACHABLE",
2777 	[RTN_PROHIBIT] = "PROHIBIT",
2778 	[RTN_THROW] = "THROW",
2779 	[RTN_NAT] = "NAT",
2780 	[RTN_XRESOLVE] = "XRESOLVE",
2781 };
2782 
rtn_type(char * buf,size_t len,unsigned int t)2783 static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
2784 {
2785 	if (t < __RTN_MAX && rtn_type_names[t])
2786 		return rtn_type_names[t];
2787 	snprintf(buf, len, "type %u", t);
2788 	return buf;
2789 }
2790 
2791 /* Pretty print the trie */
fib_trie_seq_show(struct seq_file * seq,void * v)2792 static int fib_trie_seq_show(struct seq_file *seq, void *v)
2793 {
2794 	const struct fib_trie_iter *iter = seq->private;
2795 	struct key_vector *n = v;
2796 
2797 	if (IS_TRIE(node_parent_rcu(n)))
2798 		fib_table_print(seq, iter->tb);
2799 
2800 	if (IS_TNODE(n)) {
2801 		__be32 prf = htonl(n->key);
2802 
2803 		seq_indent(seq, iter->depth-1);
2804 		seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
2805 			   &prf, KEYLENGTH - n->pos - n->bits, n->bits,
2806 			   tn_info(n)->full_children,
2807 			   tn_info(n)->empty_children);
2808 	} else {
2809 		__be32 val = htonl(n->key);
2810 		struct fib_alias *fa;
2811 
2812 		seq_indent(seq, iter->depth);
2813 		seq_printf(seq, "  |-- %pI4\n", &val);
2814 
2815 		hlist_for_each_entry_rcu(fa, &n->leaf, fa_list) {
2816 			char buf1[32], buf2[32];
2817 
2818 			seq_indent(seq, iter->depth + 1);
2819 			seq_printf(seq, "  /%zu %s %s",
2820 				   KEYLENGTH - fa->fa_slen,
2821 				   rtn_scope(buf1, sizeof(buf1),
2822 					     fa->fa_info->fib_scope),
2823 				   rtn_type(buf2, sizeof(buf2),
2824 					    fa->fa_type));
2825 			if (fa->fa_dscp)
2826 				seq_printf(seq, " tos=%d",
2827 					   inet_dscp_to_dsfield(fa->fa_dscp));
2828 			seq_putc(seq, '\n');
2829 		}
2830 	}
2831 
2832 	return 0;
2833 }
2834 
2835 static const struct seq_operations fib_trie_seq_ops = {
2836 	.start  = fib_trie_seq_start,
2837 	.next   = fib_trie_seq_next,
2838 	.stop   = fib_trie_seq_stop,
2839 	.show   = fib_trie_seq_show,
2840 };
2841 
2842 struct fib_route_iter {
2843 	struct seq_net_private p;
2844 	struct fib_table *main_tb;
2845 	struct key_vector *tnode;
2846 	loff_t	pos;
2847 	t_key	key;
2848 };
2849 
fib_route_get_idx(struct fib_route_iter * iter,loff_t pos)2850 static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
2851 					    loff_t pos)
2852 {
2853 	struct key_vector *l, **tp = &iter->tnode;
2854 	t_key key;
2855 
2856 	/* use cached location of previously found key */
2857 	if (iter->pos > 0 && pos >= iter->pos) {
2858 		key = iter->key;
2859 	} else {
2860 		iter->pos = 1;
2861 		key = 0;
2862 	}
2863 
2864 	pos -= iter->pos;
2865 
2866 	while ((l = leaf_walk_rcu(tp, key)) && (pos-- > 0)) {
2867 		key = l->key + 1;
2868 		iter->pos++;
2869 		l = NULL;
2870 
2871 		/* handle unlikely case of a key wrap */
2872 		if (!key)
2873 			break;
2874 	}
2875 
2876 	if (l)
2877 		iter->key = l->key;	/* remember it */
2878 	else
2879 		iter->pos = 0;		/* forget it */
2880 
2881 	return l;
2882 }
2883 
fib_route_seq_start(struct seq_file * seq,loff_t * pos)2884 static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
2885 	__acquires(RCU)
2886 {
2887 	struct fib_route_iter *iter = seq->private;
2888 	struct fib_table *tb;
2889 	struct trie *t;
2890 
2891 	rcu_read_lock();
2892 
2893 	tb = fib_get_table(seq_file_net(seq), RT_TABLE_MAIN);
2894 	if (!tb)
2895 		return NULL;
2896 
2897 	iter->main_tb = tb;
2898 	t = (struct trie *)tb->tb_data;
2899 	iter->tnode = t->kv;
2900 
2901 	if (*pos != 0)
2902 		return fib_route_get_idx(iter, *pos);
2903 
2904 	iter->pos = 0;
2905 	iter->key = KEY_MAX;
2906 
2907 	return SEQ_START_TOKEN;
2908 }
2909 
fib_route_seq_next(struct seq_file * seq,void * v,loff_t * pos)2910 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
2911 {
2912 	struct fib_route_iter *iter = seq->private;
2913 	struct key_vector *l = NULL;
2914 	t_key key = iter->key + 1;
2915 
2916 	++*pos;
2917 
2918 	/* only allow key of 0 for start of sequence */
2919 	if ((v == SEQ_START_TOKEN) || key)
2920 		l = leaf_walk_rcu(&iter->tnode, key);
2921 
2922 	if (l) {
2923 		iter->key = l->key;
2924 		iter->pos++;
2925 	} else {
2926 		iter->pos = 0;
2927 	}
2928 
2929 	return l;
2930 }
2931 
fib_route_seq_stop(struct seq_file * seq,void * v)2932 static void fib_route_seq_stop(struct seq_file *seq, void *v)
2933 	__releases(RCU)
2934 {
2935 	rcu_read_unlock();
2936 }
2937 
fib_flag_trans(int type,__be32 mask,struct fib_info * fi)2938 static unsigned int fib_flag_trans(int type, __be32 mask, struct fib_info *fi)
2939 {
2940 	unsigned int flags = 0;
2941 
2942 	if (type == RTN_UNREACHABLE || type == RTN_PROHIBIT)
2943 		flags = RTF_REJECT;
2944 	if (fi) {
2945 		const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2946 
2947 		if (nhc->nhc_gw.ipv4)
2948 			flags |= RTF_GATEWAY;
2949 	}
2950 	if (mask == htonl(0xFFFFFFFF))
2951 		flags |= RTF_HOST;
2952 	flags |= RTF_UP;
2953 	return flags;
2954 }
2955 
2956 /*
2957  *	This outputs /proc/net/route.
2958  *	The format of the file is not supposed to be changed
2959  *	and needs to be same as fib_hash output to avoid breaking
2960  *	legacy utilities
2961  */
fib_route_seq_show(struct seq_file * seq,void * v)2962 static int fib_route_seq_show(struct seq_file *seq, void *v)
2963 {
2964 	struct fib_route_iter *iter = seq->private;
2965 	struct fib_table *tb = iter->main_tb;
2966 	struct fib_alias *fa;
2967 	struct key_vector *l = v;
2968 	__be32 prefix;
2969 
2970 	if (v == SEQ_START_TOKEN) {
2971 		seq_printf(seq, "%-127s\n", "Iface\tDestination\tGateway "
2972 			   "\tFlags\tRefCnt\tUse\tMetric\tMask\t\tMTU"
2973 			   "\tWindow\tIRTT");
2974 		return 0;
2975 	}
2976 
2977 	prefix = htonl(l->key);
2978 
2979 	hlist_for_each_entry_rcu(fa, &l->leaf, fa_list) {
2980 		struct fib_info *fi = fa->fa_info;
2981 		__be32 mask = inet_make_mask(KEYLENGTH - fa->fa_slen);
2982 		unsigned int flags = fib_flag_trans(fa->fa_type, mask, fi);
2983 
2984 		if ((fa->fa_type == RTN_BROADCAST) ||
2985 		    (fa->fa_type == RTN_MULTICAST))
2986 			continue;
2987 
2988 		if (fa->tb_id != tb->tb_id)
2989 			continue;
2990 
2991 		seq_setwidth(seq, 127);
2992 
2993 		if (fi) {
2994 			struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
2995 			__be32 gw = 0;
2996 
2997 			if (nhc->nhc_gw_family == AF_INET)
2998 				gw = nhc->nhc_gw.ipv4;
2999 
3000 			seq_printf(seq,
3001 				   "%s\t%08X\t%08X\t%04X\t%d\t%u\t"
3002 				   "%d\t%08X\t%d\t%u\t%u",
3003 				   nhc->nhc_dev ? nhc->nhc_dev->name : "*",
3004 				   prefix, gw, flags, 0, 0,
3005 				   fi->fib_priority,
3006 				   mask,
3007 				   (fi->fib_advmss ?
3008 				    fi->fib_advmss + 40 : 0),
3009 				   fi->fib_window,
3010 				   fi->fib_rtt >> 3);
3011 		} else {
3012 			seq_printf(seq,
3013 				   "*\t%08X\t%08X\t%04X\t%d\t%u\t"
3014 				   "%d\t%08X\t%d\t%u\t%u",
3015 				   prefix, 0, flags, 0, 0, 0,
3016 				   mask, 0, 0, 0);
3017 		}
3018 		seq_pad(seq, '\n');
3019 	}
3020 
3021 	return 0;
3022 }
3023 
3024 static const struct seq_operations fib_route_seq_ops = {
3025 	.start  = fib_route_seq_start,
3026 	.next   = fib_route_seq_next,
3027 	.stop   = fib_route_seq_stop,
3028 	.show   = fib_route_seq_show,
3029 };
3030 
fib_proc_init(struct net * net)3031 int __net_init fib_proc_init(struct net *net)
3032 {
3033 	if (!proc_create_net("fib_trie", 0444, net->proc_net, &fib_trie_seq_ops,
3034 			sizeof(struct fib_trie_iter)))
3035 		goto out1;
3036 
3037 	if (!proc_create_net_single("fib_triestat", 0444, net->proc_net,
3038 			fib_triestat_seq_show, NULL))
3039 		goto out2;
3040 
3041 	if (!proc_create_net("route", 0444, net->proc_net, &fib_route_seq_ops,
3042 			sizeof(struct fib_route_iter)))
3043 		goto out3;
3044 
3045 	return 0;
3046 
3047 out3:
3048 	remove_proc_entry("fib_triestat", net->proc_net);
3049 out2:
3050 	remove_proc_entry("fib_trie", net->proc_net);
3051 out1:
3052 	return -ENOMEM;
3053 }
3054 
fib_proc_exit(struct net * net)3055 void __net_exit fib_proc_exit(struct net *net)
3056 {
3057 	remove_proc_entry("fib_trie", net->proc_net);
3058 	remove_proc_entry("fib_triestat", net->proc_net);
3059 	remove_proc_entry("route", net->proc_net);
3060 }
3061 
3062 #endif /* CONFIG_PROC_FS */
3063