xref: /freebsd/sys/netinet/in_fib_dxr.c (revision 42b3c16e3051fdc04acc6276dd5d97dbe80ae7eb)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2012-2024 Marko Zec
5  * Copyright (c) 2005, 2018 University of Zagreb
6  * Copyright (c) 2005 International Computer Science Institute
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 /*
31  * An implementation of DXR, a simple IPv4 LPM scheme with compact lookup
32  * structures and a trivial search procedure.  More significant bits of
33  * the search key are used to directly index a two-stage trie, while the
34  * remaining bits are used for finding the next hop in a sorted array.
35  * More details in:
36  *
37  * M. Zec, L. Rizzo, M. Mikuc, DXR: towards a billion routing lookups per
38  * second in software, ACM SIGCOMM Computer Communication Review, September
39  * 2012
40  *
41  * M. Zec, M. Mikuc, Pushing the envelope: beyond two billion IP routing
42  * lookups per second on commodity CPUs, IEEE SoftCOM, September 2017, Split
43  */
44 
45 #include <sys/cdefs.h>
46 #include "opt_inet.h"
47 
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/ctype.h>
51 #include <sys/epoch.h>
52 #include <sys/malloc.h>
53 #include <sys/module.h>
54 #include <sys/socket.h>
55 #include <sys/sysctl.h>
56 #include <sys/syslog.h>
57 
58 #include <vm/uma.h>
59 
60 #include <netinet/in.h>
61 #include <netinet/in_fib.h>
62 
63 #include <net/route.h>
64 #include <net/route/route_ctl.h>
65 #include <net/route/fib_algo.h>
66 
67 #define	DXR_TRIE_BITS		20
68 
69 CTASSERT(DXR_TRIE_BITS >= 16 && DXR_TRIE_BITS <= 24);
70 
71 #if DXR_TRIE_BITS > 16
72 #define	DXR_D			16
73 #else
74 #define	DXR_D			(DXR_TRIE_BITS - 1)
75 #endif
76 
77 #define	D_TBL_SIZE		(1 << DXR_D)
78 #define	DIRECT_TBL_SIZE		(1 << DXR_TRIE_BITS)
79 #define	DXR_RANGE_MASK		(0xffffffffU >> DXR_TRIE_BITS)
80 #define	DXR_RANGE_SHIFT		(32 - DXR_TRIE_BITS)
81 
82 #define	DESC_BASE_BITS		22
83 #define	DESC_FRAGMENTS_BITS	(32 - DESC_BASE_BITS)
84 #define	BASE_MAX		((1 << DESC_BASE_BITS) - 1)
85 #define	RTBL_SIZE_INCR		(BASE_MAX / 64)
86 
87 #if DXR_TRIE_BITS < 24
88 #define	FRAGS_MASK_SHORT	((1 << (23 - DXR_TRIE_BITS)) - 1)
89 #else
90 #define	FRAGS_MASK_SHORT	0
91 #endif
92 #define	FRAGS_PREF_SHORT	(((1 << DESC_FRAGMENTS_BITS) - 1) & \
93 				 ~FRAGS_MASK_SHORT)
94 #define	FRAGS_MARK_XL		(FRAGS_PREF_SHORT - 1)
95 #define	FRAGS_MARK_HIT		(FRAGS_PREF_SHORT - 2)
96 
97 #define	IS_SHORT_FORMAT(x)	((x & FRAGS_PREF_SHORT) == FRAGS_PREF_SHORT)
98 #define	IS_LONG_FORMAT(x)	((x & FRAGS_PREF_SHORT) != FRAGS_PREF_SHORT)
99 #define	IS_XL_FORMAT(x)		(x == FRAGS_MARK_XL)
100 
101 #define	RE_SHORT_MAX_NH		((1 << (DXR_TRIE_BITS - 8)) - 1)
102 
103 #define	CHUNK_HASH_BITS		16
104 #define	CHUNK_HASH_SIZE		(1 << CHUNK_HASH_BITS)
105 #define	CHUNK_HASH_MASK		(CHUNK_HASH_SIZE - 1)
106 
107 #define	TRIE_HASH_BITS		16
108 #define	TRIE_HASH_SIZE		(1 << TRIE_HASH_BITS)
109 #define	TRIE_HASH_MASK		(TRIE_HASH_SIZE - 1)
110 
111 #define	XTBL_SIZE_INCR		(DIRECT_TBL_SIZE / 16)
112 
113 #define	UNUSED_BUCKETS		8
114 
115 /* Lookup structure elements */
116 
117 struct direct_entry {
118 	uint32_t		fragments: DESC_FRAGMENTS_BITS,
119 				base: DESC_BASE_BITS;
120 };
121 
122 struct range_entry_long {
123 	uint32_t		start: DXR_RANGE_SHIFT,
124 				nexthop: DXR_TRIE_BITS;
125 };
126 
127 #if DXR_TRIE_BITS < 24
128 struct range_entry_short {
129 	uint16_t		start: DXR_RANGE_SHIFT - 8,
130 				nexthop: DXR_TRIE_BITS - 8;
131 };
132 #endif
133 
134 /* Auxiliary structures */
135 
136 struct heap_entry {
137 	uint32_t		start;
138 	uint32_t		end;
139 	uint32_t		preflen;
140 	uint32_t		nexthop;
141 };
142 
143 struct chunk_desc {
144 	LIST_ENTRY(chunk_desc)	cd_all_le;
145 	LIST_ENTRY(chunk_desc)	cd_hash_le;
146 	uint32_t		cd_hash;
147 	uint32_t		cd_refcnt;
148 	uint32_t		cd_base;
149 	uint32_t		cd_cur_size;
150 	uint32_t		cd_max_size;
151 };
152 
153 struct trie_desc {
154 	LIST_ENTRY(trie_desc)	td_all_le;
155 	LIST_ENTRY(trie_desc)	td_hash_le;
156 	uint32_t		td_hash;
157 	uint32_t		td_index;
158 	uint32_t		td_refcnt;
159 };
160 
161 struct dxr_aux {
162 	/* Glue to external state */
163 	struct fib_data		*fd;
164 	uint32_t		fibnum;
165 	int			refcnt;
166 
167 	/* Auxiliary build-time tables */
168 	struct direct_entry	direct_tbl[DIRECT_TBL_SIZE];
169 	uint16_t		d_tbl[D_TBL_SIZE];
170 	struct direct_entry	*x_tbl;
171 	union {
172 		struct range_entry_long	re;
173 		uint32_t	fragments;
174 	}			*range_tbl;
175 
176 	/* Auxiliary internal state */
177 	uint32_t		updates_mask[DIRECT_TBL_SIZE / 32];
178 	struct trie_desc	*trietbl[D_TBL_SIZE];
179 	LIST_HEAD(, chunk_desc)	chunk_hashtbl[CHUNK_HASH_SIZE];
180 	LIST_HEAD(, chunk_desc)	all_chunks;
181 	LIST_HEAD(, chunk_desc) unused_chunks[UNUSED_BUCKETS];
182 	LIST_HEAD(, trie_desc)	trie_hashtbl[TRIE_HASH_SIZE];
183 	LIST_HEAD(, trie_desc)	all_trie;
184 	LIST_HEAD(, trie_desc)	unused_trie; /* abuses hash link entry */
185 	struct sockaddr_in	dst;
186 	struct sockaddr_in	mask;
187 	struct heap_entry	heap[33];
188 	uint32_t		prefixes;
189 	uint32_t		updates_low;
190 	uint32_t		updates_high;
191 	uint32_t		unused_chunks_size;
192 	uint32_t		xtbl_size;
193 	uint32_t		all_trie_cnt;
194 	uint32_t		unused_trie_cnt;
195 	uint32_t		trie_rebuilt_prefixes;
196 	uint32_t		heap_index;
197 	uint32_t		d_bits;
198 	uint32_t		rtbl_size;
199 	uint32_t		rtbl_top;
200 	uint32_t		rtbl_work_frags;
201 	uint32_t		work_chunk;
202 };
203 
204 /* Main lookup structure container */
205 
206 struct dxr {
207 	/* Lookup tables */
208 	void			*d;
209 	void			*x;
210 	void			*r;
211 	struct nhop_object	**nh_tbl;
212 
213 	/* Glue to external state */
214 	struct dxr_aux		*aux;
215 	struct fib_data		*fd;
216 	struct epoch_context	epoch_ctx;
217 	uint32_t		fibnum;
218 	uint16_t		d_shift;
219 	uint16_t		x_shift;
220 	uint32_t		x_mask;
221 };
222 
223 static MALLOC_DEFINE(M_DXRLPM, "dxr", "DXR LPM");
224 static MALLOC_DEFINE(M_DXRAUX, "dxr aux", "DXR auxiliary");
225 
226 uma_zone_t chunk_zone;
227 uma_zone_t trie_zone;
228 
229 VNET_DEFINE_STATIC(int, frag_limit) = 100;
230 #define	V_frag_limit	VNET(frag_limit)
231 
232 /* Binary search for a matching address range */
233 #define	DXR_LOOKUP_STAGE					\
234 	if (masked_dst < range[middle].start) {			\
235 		upperbound = middle;				\
236 		middle = (middle + lowerbound) / 2;		\
237 	} else if (masked_dst < range[middle + 1].start)	\
238 		return (range[middle].nexthop);			\
239 	else {							\
240 		lowerbound = middle + 1;			\
241 		middle = (upperbound + middle + 1) / 2;		\
242 	}							\
243 	if (upperbound == lowerbound)				\
244 		return (range[lowerbound].nexthop);
245 
246 static int
247 range_lookup(struct range_entry_long *rt, struct direct_entry de, uint32_t dst)
248 {
249 	uint32_t base;
250 	uint32_t upperbound;
251 	uint32_t middle;
252 	uint32_t lowerbound;
253 	uint32_t masked_dst;
254 
255 	base = de.base;
256 	lowerbound = 0;
257 	masked_dst = dst & DXR_RANGE_MASK;
258 
259 #if DXR_TRIE_BITS < 24
260 	if (__predict_true(IS_SHORT_FORMAT(de.fragments))) {
261 		upperbound = de.fragments & FRAGS_MASK_SHORT;
262 		struct range_entry_short *range =
263 		    (struct range_entry_short *) &rt[base];
264 
265 		masked_dst >>= 8;
266 		middle = upperbound;
267 		upperbound = upperbound * 2 + 1;
268 
269 		for (;;) {
270 			DXR_LOOKUP_STAGE
271 			DXR_LOOKUP_STAGE
272 		}
273 	}
274 #endif
275 
276 	upperbound = de.fragments;
277 	middle = upperbound / 2;
278 	struct range_entry_long *range = &rt[base];
279 	if (__predict_false(IS_XL_FORMAT(de.fragments))) {
280 		upperbound = *((uint32_t *) range);
281 		range++;
282 		middle = upperbound / 2;
283 	}
284 
285 	for (;;) {
286 		DXR_LOOKUP_STAGE
287 		DXR_LOOKUP_STAGE
288 	}
289 }
290 
291 #define DXR_LOOKUP_DEFINE(D)						\
292 	static int inline						\
293 	dxr_lookup_##D(struct dxr *dxr, uint32_t dst)			\
294 	{								\
295 		struct direct_entry de;					\
296 		uint16_t *dt = dxr->d;					\
297 		struct direct_entry *xt = dxr->x;			\
298 									\
299 		de = xt[(dt[dst >> (32 - (D))] << (DXR_TRIE_BITS - (D))) \
300 		    + ((dst >> DXR_RANGE_SHIFT) &			\
301 		    (0xffffffffU >> (32 - DXR_TRIE_BITS + (D))))];	\
302 		if (__predict_true(de.fragments == FRAGS_MARK_HIT))	\
303 			return (de.base);				\
304 		return (range_lookup(dxr->r, de, dst));			\
305 	}								\
306 									\
307 	static struct nhop_object *					\
308 	dxr_fib_lookup_##D(void *algo_data,				\
309 	    const struct flm_lookup_key key, uint32_t scopeid __unused)	\
310 	{								\
311 		struct dxr *dxr = algo_data;				\
312 									\
313 		return (dxr->nh_tbl[dxr_lookup_##D(dxr,			\
314 		    ntohl(key.addr4.s_addr))]);				\
315 	}
316 
317 #if DXR_TRIE_BITS > 16
318 DXR_LOOKUP_DEFINE(16)
319 #endif
320 DXR_LOOKUP_DEFINE(15)
321 DXR_LOOKUP_DEFINE(14)
322 DXR_LOOKUP_DEFINE(13)
323 DXR_LOOKUP_DEFINE(12)
324 DXR_LOOKUP_DEFINE(11)
325 DXR_LOOKUP_DEFINE(10)
326 DXR_LOOKUP_DEFINE(9)
327 
328 static int inline
329 dxr_lookup(struct dxr *dxr, uint32_t dst)
330 {
331 	struct direct_entry de;
332 	uint16_t *dt = dxr->d;
333 	struct direct_entry *xt = dxr->x;
334 
335 	de = xt[(dt[dst >> dxr->d_shift] << dxr->x_shift) +
336 	    ((dst >> DXR_RANGE_SHIFT) & dxr->x_mask)];
337 	if (__predict_true(de.fragments == FRAGS_MARK_HIT))
338 		return (de.base);
339 	return (range_lookup(dxr->r, de, dst));
340 }
341 
342 static void
343 initheap(struct dxr_aux *da, uint32_t dst_u32, uint32_t chunk)
344 {
345 	struct heap_entry *fhp = &da->heap[0];
346 	struct rtentry *rt;
347 	struct route_nhop_data rnd;
348 
349 	da->heap_index = 0;
350 	da->dst.sin_addr.s_addr = htonl(dst_u32);
351 	rt = fib4_lookup_rt(da->fibnum, da->dst.sin_addr, 0, NHR_UNLOCKED,
352 	    &rnd);
353 	if (rt != NULL) {
354 		struct in_addr addr;
355 		uint32_t scopeid;
356 
357 		rt_get_inet_prefix_plen(rt, &addr, &fhp->preflen, &scopeid);
358 		fhp->start = ntohl(addr.s_addr);
359 		fhp->end = fhp->start;
360 		if (fhp->preflen < 32)
361 			fhp->end |= (0xffffffffU >> fhp->preflen);
362 		fhp->nexthop = fib_get_nhop_idx(da->fd, rnd.rnd_nhop);
363 	} else {
364 		fhp->preflen = fhp->nexthop = fhp->start = 0;
365 		fhp->end = 0xffffffffU;
366 	}
367 }
368 
369 static uint32_t
370 chunk_size(struct dxr_aux *da, struct direct_entry *fdesc)
371 {
372 
373 	if (IS_SHORT_FORMAT(fdesc->fragments))
374 		return ((fdesc->fragments & FRAGS_MASK_SHORT) + 1);
375 	else if (IS_XL_FORMAT(fdesc->fragments))
376 		return (da->range_tbl[fdesc->base].fragments + 2);
377 	else /* if (IS_LONG_FORMAT(fdesc->fragments)) */
378 		return (fdesc->fragments + 1);
379 }
380 
381 static uint32_t
382 chunk_hash(struct dxr_aux *da, struct direct_entry *fdesc)
383 {
384 	uint32_t size = chunk_size(da, fdesc);
385 	uint32_t *p = (uint32_t *) &da->range_tbl[fdesc->base];
386 	uint32_t *l = (uint32_t *) &da->range_tbl[fdesc->base + size];
387 	uint32_t hash = fdesc->fragments;
388 
389 	for (; p < l; p++)
390 		hash = (hash << 7) + (hash >> 13) + *p;
391 
392 	return (hash + (hash >> 16));
393 }
394 
395 static int
396 chunk_ref(struct dxr_aux *da, uint32_t chunk)
397 {
398 	struct direct_entry *fdesc = &da->direct_tbl[chunk];
399 	struct chunk_desc *cdp, *empty_cdp;
400 	uint32_t base = fdesc->base;
401 	uint32_t size = chunk_size(da, fdesc);
402 	uint32_t hash = chunk_hash(da, fdesc);
403 	int i;
404 
405 	/* Find an existing descriptor */
406 	LIST_FOREACH(cdp, &da->chunk_hashtbl[hash & CHUNK_HASH_MASK],
407 	    cd_hash_le) {
408 		if (cdp->cd_hash != hash || cdp->cd_cur_size != size ||
409 		    memcmp(&da->range_tbl[base], &da->range_tbl[cdp->cd_base],
410 		    sizeof(struct range_entry_long) * size))
411 			continue;
412 		da->rtbl_top = fdesc->base;
413 		fdesc->base = cdp->cd_base;
414 		cdp->cd_refcnt++;
415 		return (0);
416 	}
417 
418 	/* No matching chunks found. Find an empty one to recycle. */
419 	for (cdp = NULL, i = size; cdp == NULL && i < UNUSED_BUCKETS; i++)
420 		cdp = LIST_FIRST(&da->unused_chunks[i]);
421 
422 	if (cdp == NULL)
423 		LIST_FOREACH(empty_cdp, &da->unused_chunks[0], cd_hash_le)
424 			if (empty_cdp->cd_max_size >= size && (cdp == NULL ||
425 			    empty_cdp->cd_max_size < cdp->cd_max_size)) {
426 				cdp = empty_cdp;
427 				if (empty_cdp->cd_max_size == size)
428 					break;
429 			}
430 
431 	if (cdp != NULL) {
432 		/* Copy from heap into the recycled chunk */
433 		bcopy(&da->range_tbl[fdesc->base], &da->range_tbl[cdp->cd_base],
434 		    size * sizeof(struct range_entry_long));
435 		fdesc->base = cdp->cd_base;
436 		da->rtbl_top -= size;
437 		da->unused_chunks_size -= cdp->cd_max_size;
438 		if (cdp->cd_max_size > size) {
439 			/* Split the range in two, need a new descriptor */
440 			empty_cdp = uma_zalloc(chunk_zone, M_NOWAIT);
441 			if (empty_cdp == NULL)
442 				return (1);
443 			LIST_INSERT_BEFORE(cdp, empty_cdp, cd_all_le);
444 			empty_cdp->cd_base = cdp->cd_base + size;
445 			empty_cdp->cd_cur_size = 0;
446 			empty_cdp->cd_max_size = cdp->cd_max_size - size;
447 
448 			i = empty_cdp->cd_max_size;
449 			if (i >= UNUSED_BUCKETS)
450 				i = 0;
451 			LIST_INSERT_HEAD(&da->unused_chunks[i], empty_cdp,
452 			    cd_hash_le);
453 
454 			da->unused_chunks_size += empty_cdp->cd_max_size;
455 			cdp->cd_max_size = size;
456 		}
457 		LIST_REMOVE(cdp, cd_hash_le);
458 	} else {
459 		/* Alloc a new descriptor at the top of the heap*/
460 		cdp = uma_zalloc(chunk_zone, M_NOWAIT);
461 		if (cdp == NULL)
462 			return (1);
463 		cdp->cd_max_size = size;
464 		cdp->cd_base = fdesc->base;
465 		LIST_INSERT_HEAD(&da->all_chunks, cdp, cd_all_le);
466 		MPASS(cdp->cd_base + cdp->cd_max_size == da->rtbl_top);
467 	}
468 
469 	cdp->cd_hash = hash;
470 	cdp->cd_refcnt = 1;
471 	cdp->cd_cur_size = size;
472 	LIST_INSERT_HEAD(&da->chunk_hashtbl[hash & CHUNK_HASH_MASK], cdp,
473 	    cd_hash_le);
474 	if (da->rtbl_top >= da->rtbl_size) {
475 		if (da->rtbl_top >= BASE_MAX) {
476 			FIB_PRINTF(LOG_ERR, da->fd,
477 			    "structural limit exceeded at %d "
478 			    "range table elements", da->rtbl_top);
479 			return (1);
480 		}
481 		da->rtbl_size += RTBL_SIZE_INCR;
482 		i = (BASE_MAX - da->rtbl_top) * LOG_DEBUG / BASE_MAX;
483 		FIB_PRINTF(i, da->fd, "range table at %d%% structural limit",
484 		    da->rtbl_top * 100 / BASE_MAX);
485 		da->range_tbl = realloc(da->range_tbl,
486 		    sizeof(*da->range_tbl) * da->rtbl_size + FRAGS_PREF_SHORT,
487 		    M_DXRAUX, M_NOWAIT);
488 		if (da->range_tbl == NULL) {
489 			FIB_PRINTF(LOG_NOTICE, da->fd,
490 			    "Unable to allocate DXR range table");
491 			return (1);
492 		}
493 	}
494 
495 	return (0);
496 }
497 
498 static void
499 chunk_unref(struct dxr_aux *da, uint32_t chunk)
500 {
501 	struct direct_entry *fdesc = &da->direct_tbl[chunk];
502 	struct chunk_desc *cdp, *cdp2;
503 	uint32_t base = fdesc->base;
504 	uint32_t size = chunk_size(da, fdesc);
505 	uint32_t hash = chunk_hash(da, fdesc);
506 	int i;
507 
508 	/* Find the corresponding descriptor */
509 	LIST_FOREACH(cdp, &da->chunk_hashtbl[hash & CHUNK_HASH_MASK],
510 	    cd_hash_le)
511 		if (cdp->cd_hash == hash && cdp->cd_cur_size == size &&
512 		    memcmp(&da->range_tbl[base], &da->range_tbl[cdp->cd_base],
513 		    sizeof(struct range_entry_long) * size) == 0)
514 			break;
515 
516 	MPASS(cdp != NULL);
517 	if (--cdp->cd_refcnt > 0)
518 		return;
519 
520 	LIST_REMOVE(cdp, cd_hash_le);
521 	da->unused_chunks_size += cdp->cd_max_size;
522 	cdp->cd_cur_size = 0;
523 
524 	/* Attempt to merge with the preceding chunk, if empty */
525 	cdp2 = LIST_NEXT(cdp, cd_all_le);
526 	if (cdp2 != NULL && cdp2->cd_cur_size == 0) {
527 		MPASS(cdp2->cd_base + cdp2->cd_max_size == cdp->cd_base);
528 		LIST_REMOVE(cdp, cd_all_le);
529 		LIST_REMOVE(cdp2, cd_hash_le);
530 		cdp2->cd_max_size += cdp->cd_max_size;
531 		uma_zfree(chunk_zone, cdp);
532 		cdp = cdp2;
533 	}
534 
535 	/* Attempt to merge with the subsequent chunk, if empty */
536 	cdp2 = LIST_PREV(cdp, &da->all_chunks, chunk_desc, cd_all_le);
537 	if (cdp2 != NULL && cdp2->cd_cur_size == 0) {
538 		MPASS(cdp->cd_base + cdp->cd_max_size == cdp2->cd_base);
539 		LIST_REMOVE(cdp, cd_all_le);
540 		LIST_REMOVE(cdp2, cd_hash_le);
541 		cdp2->cd_max_size += cdp->cd_max_size;
542 		cdp2->cd_base = cdp->cd_base;
543 		uma_zfree(chunk_zone, cdp);
544 		cdp = cdp2;
545 	}
546 
547 	if (cdp->cd_base + cdp->cd_max_size == da->rtbl_top) {
548 		/* Free the chunk on the top of the range heap, trim the heap */
549 		MPASS(cdp == LIST_FIRST(&da->all_chunks));
550 		da->rtbl_top -= cdp->cd_max_size;
551 		da->unused_chunks_size -= cdp->cd_max_size;
552 		LIST_REMOVE(cdp, cd_all_le);
553 		uma_zfree(chunk_zone, cdp);
554 		return;
555 	}
556 
557 	i = cdp->cd_max_size;
558 	if (i >= UNUSED_BUCKETS)
559 		i = 0;
560 	LIST_INSERT_HEAD(&da->unused_chunks[i], cdp, cd_hash_le);
561 }
562 
563 static uint32_t
564 trie_hash(struct dxr_aux *da, uint32_t dxr_x, uint32_t index)
565 {
566 	uint32_t i, *val;
567 	uint32_t hash = 0;
568 
569 	for (i = 0; i < (1 << dxr_x); i++) {
570 		hash = (hash << 3) ^ (hash >> 3);
571 		val = (uint32_t *)
572 		    (void *) &da->direct_tbl[(index << dxr_x) + i];
573 		hash += (*val << 5);
574 		hash += (*val >> 5);
575 	}
576 
577 	return (hash + (hash >> 16));
578 }
579 
580 static int
581 trie_ref(struct dxr_aux *da, uint32_t index)
582 {
583 	struct trie_desc *tp;
584 	uint32_t dxr_d = da->d_bits;
585 	uint32_t dxr_x = DXR_TRIE_BITS - dxr_d;
586 	uint32_t hash = trie_hash(da, dxr_x, index);
587 
588 	/* Find an existing descriptor */
589 	LIST_FOREACH(tp, &da->trie_hashtbl[hash & TRIE_HASH_MASK], td_hash_le)
590 		if (tp->td_hash == hash &&
591 		    memcmp(&da->direct_tbl[index << dxr_x],
592 		    &da->x_tbl[tp->td_index << dxr_x],
593 		    sizeof(*da->x_tbl) << dxr_x) == 0) {
594 			tp->td_refcnt++;
595 			da->trietbl[index] = tp;
596 			return(tp->td_index);
597 		}
598 
599 	tp = LIST_FIRST(&da->unused_trie);
600 	if (tp != NULL) {
601 		LIST_REMOVE(tp, td_hash_le);
602 		da->unused_trie_cnt--;
603 	} else {
604 		tp = uma_zalloc(trie_zone, M_NOWAIT);
605 		if (tp == NULL)
606 			return (-1);
607 		LIST_INSERT_HEAD(&da->all_trie, tp, td_all_le);
608 		tp->td_index = da->all_trie_cnt++;
609 	}
610 
611 	tp->td_hash = hash;
612 	tp->td_refcnt = 1;
613 	LIST_INSERT_HEAD(&da->trie_hashtbl[hash & TRIE_HASH_MASK], tp,
614 	   td_hash_le);
615 	memcpy(&da->x_tbl[tp->td_index << dxr_x],
616 	    &da->direct_tbl[index << dxr_x], sizeof(*da->x_tbl) << dxr_x);
617 	da->trietbl[index] = tp;
618 	if (da->all_trie_cnt >= da->xtbl_size >> dxr_x) {
619 		da->xtbl_size += XTBL_SIZE_INCR;
620 		da->x_tbl = realloc(da->x_tbl,
621 		    sizeof(*da->x_tbl) * da->xtbl_size, M_DXRAUX, M_NOWAIT);
622 		if (da->x_tbl == NULL) {
623 			FIB_PRINTF(LOG_NOTICE, da->fd,
624 			    "Unable to allocate DXR extension table");
625 			return (-1);
626 		}
627 	}
628 	return(tp->td_index);
629 }
630 
631 static void
632 trie_unref(struct dxr_aux *da, uint32_t index)
633 {
634 	struct trie_desc *tp = da->trietbl[index];
635 
636 	if (tp == NULL)
637 		return;
638 	da->trietbl[index] = NULL;
639 	if (--tp->td_refcnt > 0)
640 		return;
641 
642 	LIST_REMOVE(tp, td_hash_le);
643 	da->unused_trie_cnt++;
644 	if (tp->td_index != da->all_trie_cnt - 1) {
645 		LIST_INSERT_HEAD(&da->unused_trie, tp, td_hash_le);
646 		return;
647 	}
648 
649 	do {
650 		da->all_trie_cnt--;
651 		da->unused_trie_cnt--;
652 		LIST_REMOVE(tp, td_all_le);
653 		uma_zfree(trie_zone, tp);
654 		LIST_FOREACH(tp, &da->unused_trie, td_hash_le)
655 			if (tp->td_index == da->all_trie_cnt - 1) {
656 				LIST_REMOVE(tp, td_hash_le);
657 				break;
658 			}
659 	} while (tp != NULL);
660 }
661 
662 static void
663 heap_inject(struct dxr_aux *da, uint32_t start, uint32_t end, uint32_t preflen,
664     uint32_t nh)
665 {
666 	struct heap_entry *fhp;
667 	int i;
668 
669 	for (i = da->heap_index; i >= 0; i--) {
670 		if (preflen > da->heap[i].preflen)
671 			break;
672 		else if (preflen < da->heap[i].preflen)
673 			da->heap[i + 1] = da->heap[i];
674 		else
675 			return;
676 	}
677 
678 	fhp = &da->heap[i + 1];
679 	fhp->preflen = preflen;
680 	fhp->start = start;
681 	fhp->end = end;
682 	fhp->nexthop = nh;
683 	da->heap_index++;
684 }
685 
686 static int
687 dxr_walk(struct rtentry *rt, void *arg)
688 {
689 	struct dxr_aux *da = arg;
690 	uint32_t chunk = da->work_chunk;
691 	uint32_t first = chunk << DXR_RANGE_SHIFT;
692 	uint32_t last = first | DXR_RANGE_MASK;
693 	struct range_entry_long *fp =
694 	    &da->range_tbl[da->rtbl_top + da->rtbl_work_frags].re;
695 	struct heap_entry *fhp = &da->heap[da->heap_index];
696 	uint32_t preflen, nh, start, end, scopeid;
697 	struct in_addr addr;
698 
699 	rt_get_inet_prefix_plen(rt, &addr, &preflen, &scopeid);
700 	start = ntohl(addr.s_addr);
701 	if (start > last)
702 		return (-1);	/* Beyond chunk boundaries, we are done */
703 	if (start < first)
704 		return (0);	/* Skip this route */
705 
706 	end = start;
707 	if (preflen < 32)
708 		end |= (0xffffffffU >> preflen);
709 	nh = fib_get_nhop_idx(da->fd, rt_get_raw_nhop(rt));
710 
711 	if (start == fhp->start)
712 		heap_inject(da, start, end, preflen, nh);
713 	else {
714 		/* start > fhp->start */
715 		while (start > fhp->end) {
716 			uint32_t oend = fhp->end;
717 
718 			if (da->heap_index > 0) {
719 				fhp--;
720 				da->heap_index--;
721 			} else
722 				initheap(da, fhp->end + 1, chunk);
723 			if (fhp->end > oend && fhp->nexthop != fp->nexthop) {
724 				fp++;
725 				da->rtbl_work_frags++;
726 				fp->start = (oend + 1) & DXR_RANGE_MASK;
727 				fp->nexthop = fhp->nexthop;
728 			}
729 		}
730 		if (start > ((chunk << DXR_RANGE_SHIFT) | fp->start) &&
731 		    nh != fp->nexthop) {
732 			fp++;
733 			da->rtbl_work_frags++;
734 			fp->start = start & DXR_RANGE_MASK;
735 		} else if (da->rtbl_work_frags) {
736 			if ((--fp)->nexthop == nh)
737 				da->rtbl_work_frags--;
738 			else
739 				fp++;
740 		}
741 		fp->nexthop = nh;
742 		heap_inject(da, start, end, preflen, nh);
743 	}
744 
745 	return (0);
746 }
747 
748 static int
749 update_chunk(struct dxr_aux *da, uint32_t chunk)
750 {
751 	struct range_entry_long *fp;
752 #if DXR_TRIE_BITS < 24
753 	struct range_entry_short *fps;
754 	uint32_t start, nh, i;
755 #endif
756 	struct heap_entry *fhp;
757 	uint32_t first = chunk << DXR_RANGE_SHIFT;
758 	uint32_t last = first | DXR_RANGE_MASK;
759 
760 	if (da->direct_tbl[chunk].fragments != FRAGS_MARK_HIT)
761 		chunk_unref(da, chunk);
762 
763 	initheap(da, first, chunk);
764 
765 	fp = &da->range_tbl[da->rtbl_top].re;
766 	da->rtbl_work_frags = 0;
767 	fp->start = first & DXR_RANGE_MASK;
768 	fp->nexthop = da->heap[0].nexthop;
769 
770 	da->dst.sin_addr.s_addr = htonl(first);
771 	da->mask.sin_addr.s_addr = htonl(~DXR_RANGE_MASK);
772 
773 	da->work_chunk = chunk;
774 	rib_walk_from(da->fibnum, AF_INET, RIB_FLAG_LOCKED,
775 	    (struct sockaddr *) &da->dst, (struct sockaddr *) &da->mask,
776 	    dxr_walk, da);
777 
778 	/* Flush any remaining objects on the heap */
779 	fp = &da->range_tbl[da->rtbl_top + da->rtbl_work_frags].re;
780 	fhp = &da->heap[da->heap_index];
781 	while (fhp->preflen > DXR_TRIE_BITS) {
782 		uint32_t oend = fhp->end;
783 
784 		if (da->heap_index > 0) {
785 			fhp--;
786 			da->heap_index--;
787 		} else
788 			initheap(da, fhp->end + 1, chunk);
789 		if (fhp->end > oend && fhp->nexthop != fp->nexthop) {
790 			/* Have we crossed the upper chunk boundary? */
791 			if (oend >= last)
792 				break;
793 			fp++;
794 			da->rtbl_work_frags++;
795 			fp->start = (oend + 1) & DXR_RANGE_MASK;
796 			fp->nexthop = fhp->nexthop;
797 		}
798 	}
799 
800 	/* Direct hit if the chunk contains only a single fragment */
801 	if (da->rtbl_work_frags == 0) {
802 		da->direct_tbl[chunk].base = fp->nexthop;
803 		da->direct_tbl[chunk].fragments = FRAGS_MARK_HIT;
804 		return (0);
805 	}
806 
807 	da->direct_tbl[chunk].base = da->rtbl_top;
808 	da->direct_tbl[chunk].fragments = da->rtbl_work_frags;
809 
810 #if DXR_TRIE_BITS < 24
811 	/* Check whether the chunk can be more compactly encoded */
812 	fp = &da->range_tbl[da->rtbl_top].re;
813 	for (i = 0; i <= da->rtbl_work_frags; i++, fp++)
814 		if ((fp->start & 0xff) != 0 || fp->nexthop > RE_SHORT_MAX_NH)
815 			break;
816 	if (i == da->rtbl_work_frags + 1) {
817 		fp = &da->range_tbl[da->rtbl_top].re;
818 		fps = (void *) fp;
819 		for (i = 0; i <= da->rtbl_work_frags; i++, fp++, fps++) {
820 			start = fp->start;
821 			nh = fp->nexthop;
822 			fps->start = start >> 8;
823 			fps->nexthop = nh;
824 		}
825 		fps->start = start >> 8;
826 		fps->nexthop = nh;
827 		da->rtbl_work_frags >>= 1;
828 		da->direct_tbl[chunk].fragments =
829 		    da->rtbl_work_frags | FRAGS_PREF_SHORT;
830 	} else
831 #endif
832 	if (da->rtbl_work_frags >= FRAGS_MARK_HIT) {
833 		da->direct_tbl[chunk].fragments = FRAGS_MARK_XL;
834 		memmove(&da->range_tbl[da->rtbl_top + 1],
835 		   &da->range_tbl[da->rtbl_top],
836 		   (da->rtbl_work_frags + 1) * sizeof(*da->range_tbl));
837 		da->range_tbl[da->rtbl_top].fragments = da->rtbl_work_frags;
838 		da->rtbl_work_frags++;
839 	}
840 	da->rtbl_top += (da->rtbl_work_frags + 1);
841 	return (chunk_ref(da, chunk));
842 }
843 
844 static void
845 dxr_build(struct dxr *dxr)
846 {
847 	struct dxr_aux *da = dxr->aux;
848 	struct chunk_desc *cdp;
849 	struct rib_rtable_info rinfo;
850 	struct timeval t0, t1, t2, t3;
851 	uint32_t r_size, dxr_tot_size;
852 	uint32_t i, m, range_rebuild = 0;
853 	uint32_t range_frag;
854 	struct trie_desc *tp;
855 	uint32_t d_tbl_size, dxr_x, d_size, x_size;
856 	uint32_t ti, trie_rebuild = 0, prev_size = 0;
857 	uint32_t trie_frag;
858 
859 	MPASS(dxr->d == NULL);
860 
861 	if (da == NULL) {
862 		da = malloc(sizeof(*dxr->aux), M_DXRAUX, M_NOWAIT);
863 		if (da == NULL) {
864 			FIB_PRINTF(LOG_NOTICE, dxr->fd,
865 			    "Unable to allocate DXR aux struct");
866 			return;
867 		}
868 		dxr->aux = da;
869 		da->fibnum = dxr->fibnum;
870 		da->fd = dxr->fd;
871 		da->refcnt = 1;
872 		LIST_INIT(&da->all_chunks);
873 		LIST_INIT(&da->all_trie);
874 		da->rtbl_size = RTBL_SIZE_INCR;
875 		da->range_tbl = NULL;
876 		da->xtbl_size = XTBL_SIZE_INCR;
877 		da->x_tbl = NULL;
878 		bzero(&da->dst, sizeof(da->dst));
879 		bzero(&da->mask, sizeof(da->mask));
880 		da->dst.sin_len = sizeof(da->dst);
881 		da->mask.sin_len = sizeof(da->mask);
882 		da->dst.sin_family = AF_INET;
883 		da->mask.sin_family = AF_INET;
884 	}
885 	if (da->range_tbl == NULL) {
886 		da->range_tbl = malloc(sizeof(*da->range_tbl) * da->rtbl_size
887 		    + FRAGS_PREF_SHORT, M_DXRAUX, M_NOWAIT);
888 		if (da->range_tbl == NULL) {
889 			FIB_PRINTF(LOG_NOTICE, da->fd,
890 			    "Unable to allocate DXR range table");
891 			return;
892 		}
893 		range_rebuild = 1;
894 	}
895 	if (da->x_tbl == NULL) {
896 		da->x_tbl = malloc(sizeof(*da->x_tbl) * da->xtbl_size,
897 		    M_DXRAUX, M_NOWAIT);
898 		if (da->x_tbl == NULL) {
899 			FIB_PRINTF(LOG_NOTICE, da->fd,
900 			    "Unable to allocate DXR extension table");
901 			return;
902 		}
903 		trie_rebuild = 1;
904 	}
905 
906 	microuptime(&t0);
907 
908 	dxr->nh_tbl = fib_get_nhop_array(da->fd);
909 	fib_get_rtable_info(fib_get_rh(da->fd), &rinfo);
910 
911 	if (da->updates_low > da->updates_high)
912 		range_rebuild = 1;
913 
914 range_build:
915 	if (range_rebuild) {
916 		/* Bulk cleanup */
917 		bzero(da->chunk_hashtbl, sizeof(da->chunk_hashtbl));
918 		while ((cdp = LIST_FIRST(&da->all_chunks)) != NULL) {
919 			LIST_REMOVE(cdp, cd_all_le);
920 			uma_zfree(chunk_zone, cdp);
921 		}
922 		for (i = 0; i < UNUSED_BUCKETS; i++)
923 			LIST_INIT(&da->unused_chunks[i]);
924 		da->unused_chunks_size = 0;
925 		da->rtbl_top = 0;
926 		da->updates_low = 0;
927 		da->updates_high = DIRECT_TBL_SIZE - 1;
928 		memset(da->updates_mask, 0xff, sizeof(da->updates_mask));
929 		for (i = 0; i < DIRECT_TBL_SIZE; i++) {
930 			da->direct_tbl[i].fragments = FRAGS_MARK_HIT;
931 			da->direct_tbl[i].base = 0;
932 		}
933 	}
934 	da->prefixes = rinfo.num_prefixes;
935 
936 	/* DXR: construct direct & range table */
937 	for (i = da->updates_low; i <= da->updates_high; i++) {
938 		m = da->updates_mask[i >> 5] >> (i & 0x1f);
939 		if (m == 0)
940 			i |= 0x1f;
941 		else if (m & 1 && update_chunk(da, i) != 0)
942 			return;
943 	}
944 
945 	range_frag = 0;
946 	if (da->rtbl_top)
947 		range_frag = da->unused_chunks_size * 10000ULL / da->rtbl_top;
948 	if (range_frag > V_frag_limit) {
949 		range_rebuild = 1;
950 		goto range_build;
951 	}
952 
953 	r_size = sizeof(*da->range_tbl) * da->rtbl_top;
954 	microuptime(&t1);
955 
956 	if (range_rebuild ||
957 	    abs(fls(da->prefixes) - fls(da->trie_rebuilt_prefixes)) > 1)
958 		trie_rebuild = 1;
959 
960 trie_build:
961 	if (trie_rebuild) {
962 		da->trie_rebuilt_prefixes = da->prefixes;
963 		da->d_bits = DXR_D;
964 		da->updates_low = 0;
965 		da->updates_high = DIRECT_TBL_SIZE - 1;
966 		if (!range_rebuild)
967 			memset(da->updates_mask, 0xff,
968 			    sizeof(da->updates_mask));
969 	}
970 
971 dxr2_try_squeeze:
972 	if (trie_rebuild) {
973 		/* Bulk cleanup */
974 		bzero(da->trietbl, sizeof(da->trietbl));
975 		bzero(da->trie_hashtbl, sizeof(da->trie_hashtbl));
976 		while ((tp = LIST_FIRST(&da->all_trie)) != NULL) {
977 			LIST_REMOVE(tp, td_all_le);
978 			uma_zfree(trie_zone, tp);
979 		}
980 		LIST_INIT(&da->unused_trie);
981 		da->all_trie_cnt = da->unused_trie_cnt = 0;
982 	}
983 
984 	/* Populate d_tbl, x_tbl */
985 	dxr_x = DXR_TRIE_BITS - da->d_bits;
986 	d_tbl_size = (1 << da->d_bits);
987 
988 	for (i = da->updates_low >> dxr_x; i <= da->updates_high >> dxr_x;
989 	    i++) {
990 		if (!trie_rebuild) {
991 			m = 0;
992 			for (int j = 0; j < (1 << dxr_x); j += 32)
993 				m |= da->updates_mask[((i << dxr_x) + j) >> 5];
994 			if (m == 0)
995 				continue;
996 			trie_unref(da, i);
997 		}
998 		ti = trie_ref(da, i);
999 		if (ti < 0)
1000 			return;
1001 		da->d_tbl[i] = ti;
1002 	}
1003 
1004 	trie_frag = 0;
1005 	if (da->all_trie_cnt)
1006 		trie_frag = da->unused_trie_cnt * 10000ULL / da->all_trie_cnt;
1007 	if (trie_frag > V_frag_limit) {
1008 		trie_rebuild = 1;
1009 		goto trie_build;
1010 	}
1011 
1012 	d_size = sizeof(*da->d_tbl) * d_tbl_size;
1013 	x_size = sizeof(*da->x_tbl) * DIRECT_TBL_SIZE / d_tbl_size
1014 	    * da->all_trie_cnt;
1015 	dxr_tot_size = d_size + x_size + r_size;
1016 
1017 	if (trie_rebuild == 1) {
1018 		/* Try to find a more compact D/X split */
1019 		if (prev_size == 0 || dxr_tot_size <= prev_size)
1020 			da->d_bits--;
1021 		else {
1022 			da->d_bits++;
1023 			trie_rebuild = 2;
1024 		}
1025 		prev_size = dxr_tot_size;
1026 		goto dxr2_try_squeeze;
1027 	}
1028 	microuptime(&t2);
1029 
1030 	dxr->d = malloc(dxr_tot_size, M_DXRLPM, M_NOWAIT);
1031 	if (dxr->d == NULL) {
1032 		FIB_PRINTF(LOG_NOTICE, da->fd,
1033 		    "Unable to allocate DXR lookup table");
1034 		return;
1035 	}
1036 	memcpy(dxr->d, da->d_tbl, d_size);
1037 	dxr->x = ((char *) dxr->d) + d_size;
1038 	memcpy(dxr->x, da->x_tbl, x_size);
1039 	dxr->r = ((char *) dxr->x) + x_size;
1040 	dxr->d_shift = 32 - da->d_bits;
1041 	dxr->x_shift = dxr_x;
1042 	dxr->x_mask = 0xffffffffU >> (32 - dxr_x);
1043 	memcpy(dxr->r, da->range_tbl, r_size);
1044 
1045 	if (da->updates_low <= da->updates_high)
1046 		bzero(&da->updates_mask[da->updates_low / 32],
1047 		    (da->updates_high - da->updates_low) / 8 + 1);
1048 	da->updates_low = DIRECT_TBL_SIZE - 1;
1049 	da->updates_high = 0;
1050 	microuptime(&t3);
1051 
1052 	FIB_PRINTF(LOG_INFO, da->fd, "D%dX%dR, %d prefixes, %d nhops (max)",
1053 	    da->d_bits, dxr_x, rinfo.num_prefixes, rinfo.num_nhops);
1054 	i = dxr_tot_size * 100;
1055 	if (rinfo.num_prefixes)
1056 		i /= rinfo.num_prefixes;
1057 	FIB_PRINTF(LOG_INFO, da->fd, "%d.%02d KBytes, %d.%02d Bytes/prefix",
1058 	    dxr_tot_size / 1024, dxr_tot_size * 100 / 1024 % 100,
1059 	    i / 100, i % 100);
1060 	FIB_PRINTF(LOG_INFO, da->fd,
1061 	    "%d.%02d%% trie, %d.%02d%% range fragmentation",
1062 	    trie_frag / 100, trie_frag % 100,
1063 	    range_frag / 100, range_frag % 100);
1064 	i = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;
1065 	FIB_PRINTF(LOG_INFO, da->fd, "range table %s in %u.%03u ms",
1066 	    range_rebuild ? "rebuilt" : "updated", i / 1000, i % 1000);
1067 	i = (t2.tv_sec - t1.tv_sec) * 1000000 + t2.tv_usec - t1.tv_usec;
1068 	FIB_PRINTF(LOG_INFO, da->fd, "trie %s in %u.%03u ms",
1069 	    trie_rebuild ? "rebuilt" : "updated", i / 1000, i % 1000);
1070 	i = (t3.tv_sec - t2.tv_sec) * 1000000 + t3.tv_usec - t2.tv_usec;
1071 	FIB_PRINTF(LOG_INFO, da->fd, "snapshot forked in %u.%03u ms",
1072 	    i / 1000, i % 1000);
1073 }
1074 
1075 /*
1076  * Glue functions for attaching to the FIB_ALGO infrastructure.
1077  */
1078 
1079 static struct nhop_object *
1080 dxr_fib_lookup(void *algo_data, const struct flm_lookup_key key,
1081     uint32_t scopeid)
1082 {
1083 	struct dxr *dxr = algo_data;
1084 
1085 	return (dxr->nh_tbl[dxr_lookup(dxr, ntohl(key.addr4.s_addr))]);
1086 }
1087 
1088 static enum flm_op_result
1089 dxr_init(uint32_t fibnum, struct fib_data *fd, void *old_data, void **data)
1090 {
1091 	struct dxr *old_dxr = old_data;
1092 	struct dxr_aux *da = NULL;
1093 	struct dxr *dxr;
1094 
1095 	dxr = malloc(sizeof(*dxr), M_DXRAUX, M_NOWAIT);
1096 	if (dxr == NULL) {
1097 		FIB_PRINTF(LOG_NOTICE, fd,
1098 		    "Unable to allocate DXR container struct");
1099 		return (FLM_REBUILD);
1100 	}
1101 
1102 	/* Check whether we may reuse the old auxiliary structures */
1103 	if (old_dxr != NULL && old_dxr->aux != NULL &&
1104 	    old_dxr->aux->fd == fd) {
1105 		da = old_dxr->aux;
1106 		atomic_add_int(&da->refcnt, 1);
1107 	}
1108 
1109 	dxr->aux = da;
1110 	dxr->d = NULL;
1111 	dxr->fd = fd;
1112 	dxr->fibnum = fibnum;
1113 	*data = dxr;
1114 
1115 	return (FLM_SUCCESS);
1116 }
1117 
1118 static void
1119 dxr_destroy(void *data)
1120 {
1121 	struct dxr *dxr = data;
1122 	struct dxr_aux *da = dxr->aux;
1123 	struct chunk_desc *cdp;
1124 	struct trie_desc *tp;
1125 
1126 	free(dxr->d, M_DXRLPM);
1127 	free(dxr, M_DXRAUX);
1128 
1129 	if (da == NULL || atomic_fetchadd_int(&da->refcnt, -1) > 1)
1130 		return;
1131 
1132 	/* Release auxiliary structures */
1133 	while ((cdp = LIST_FIRST(&da->all_chunks)) != NULL) {
1134 		LIST_REMOVE(cdp, cd_all_le);
1135 		uma_zfree(chunk_zone, cdp);
1136 	}
1137 	while ((tp = LIST_FIRST(&da->all_trie)) != NULL) {
1138 		LIST_REMOVE(tp, td_all_le);
1139 		uma_zfree(trie_zone, tp);
1140 	}
1141 	free(da->range_tbl, M_DXRAUX);
1142 	free(da->x_tbl, M_DXRAUX);
1143 	free(da, M_DXRAUX);
1144 }
1145 
1146 static void
1147 epoch_dxr_destroy(epoch_context_t ctx)
1148 {
1149 	struct dxr *dxr = __containerof(ctx, struct dxr, epoch_ctx);
1150 
1151 	dxr_destroy(dxr);
1152 }
1153 
1154 static void *
1155 choose_lookup_fn(struct dxr_aux *da)
1156 {
1157 
1158 	switch (da->d_bits) {
1159 #if DXR_TRIE_BITS > 16
1160 	case 16:
1161 		return (dxr_fib_lookup_16);
1162 #endif
1163 	case 15:
1164 		return (dxr_fib_lookup_15);
1165 	case 14:
1166 		return (dxr_fib_lookup_14);
1167 	case 13:
1168 		return (dxr_fib_lookup_13);
1169 	case 12:
1170 		return (dxr_fib_lookup_12);
1171 	case 11:
1172 		return (dxr_fib_lookup_11);
1173 	case 10:
1174 		return (dxr_fib_lookup_10);
1175 	case 9:
1176 		return (dxr_fib_lookup_9);
1177 	}
1178 	return (dxr_fib_lookup);
1179 }
1180 
1181 static enum flm_op_result
1182 dxr_dump_end(void *data, struct fib_dp *dp)
1183 {
1184 	struct dxr *dxr = data;
1185 	struct dxr_aux *da;
1186 
1187 	dxr_build(dxr);
1188 
1189 	da = dxr->aux;
1190 	if (da == NULL || dxr->d == NULL)
1191 		return (FLM_REBUILD);
1192 
1193 	if (da->rtbl_top >= BASE_MAX)
1194 		return (FLM_ERROR);
1195 
1196 	dp->f = choose_lookup_fn(da);
1197 	dp->arg = dxr;
1198 
1199 	return (FLM_SUCCESS);
1200 }
1201 
1202 static enum flm_op_result
1203 dxr_dump_rib_item(struct rtentry *rt, void *data)
1204 {
1205 
1206 	return (FLM_SUCCESS);
1207 }
1208 
1209 static enum flm_op_result
1210 dxr_change_rib_item(struct rib_head *rnh, struct rib_cmd_info *rc,
1211     void *data)
1212 {
1213 
1214 	return (FLM_BATCH);
1215 }
1216 
1217 static enum flm_op_result
1218 dxr_change_rib_batch(struct rib_head *rnh, struct fib_change_queue *q,
1219     void *data)
1220 {
1221 	struct dxr *dxr = data;
1222 	struct dxr *new_dxr;
1223 	struct dxr_aux *da;
1224 	struct fib_dp new_dp;
1225 	enum flm_op_result res;
1226 	uint32_t ip, plen, hmask, start, end, i, ui;
1227 #ifdef INVARIANTS
1228 	struct rib_rtable_info rinfo;
1229 	int update_delta = 0;
1230 #endif
1231 
1232 	MPASS(data != NULL);
1233 	MPASS(q != NULL);
1234 	MPASS(q->count < q->size);
1235 
1236 	da = dxr->aux;
1237 	MPASS(da != NULL);
1238 	MPASS(da->fd == dxr->fd);
1239 	MPASS(da->refcnt > 0);
1240 
1241 	FIB_PRINTF(LOG_INFO, da->fd, "processing %d update(s)", q->count);
1242 	for (ui = 0; ui < q->count; ui++) {
1243 #ifdef INVARIANTS
1244 		if (q->entries[ui].nh_new != NULL)
1245 			update_delta++;
1246 		if (q->entries[ui].nh_old != NULL)
1247 			update_delta--;
1248 #endif
1249 		plen = q->entries[ui].plen;
1250 		ip = ntohl(q->entries[ui].addr4.s_addr);
1251 		if (plen < 32)
1252 			hmask = 0xffffffffU >> plen;
1253 		else
1254 			hmask = 0;
1255 		start = (ip & ~hmask) >> DXR_RANGE_SHIFT;
1256 		end = (ip | hmask) >> DXR_RANGE_SHIFT;
1257 
1258 		if ((start & 0x1f) == 0 && (end & 0x1f) == 0x1f)
1259 			for (i = start >> 5; i <= end >> 5; i++)
1260 				da->updates_mask[i] = 0xffffffffU;
1261 		else
1262 			for (i = start; i <= end; i++)
1263 				da->updates_mask[i >> 5] |= (1 << (i & 0x1f));
1264 		if (start < da->updates_low)
1265 			da->updates_low = start;
1266 		if (end > da->updates_high)
1267 			da->updates_high = end;
1268 	}
1269 
1270 #ifdef INVARIANTS
1271 	fib_get_rtable_info(fib_get_rh(da->fd), &rinfo);
1272 	MPASS(da->prefixes + update_delta == rinfo.num_prefixes);
1273 #endif
1274 
1275 	res = dxr_init(0, dxr->fd, data, (void **) &new_dxr);
1276 	if (res != FLM_SUCCESS)
1277 		return (res);
1278 
1279 	dxr_build(new_dxr);
1280 
1281 	/* Structural limit exceeded, hard error */
1282 	if (da->rtbl_top >= BASE_MAX) {
1283 		dxr_destroy(new_dxr);
1284 		return (FLM_ERROR);
1285 	}
1286 
1287 	if (new_dxr->d == NULL) {
1288 		dxr_destroy(new_dxr);
1289 		return (FLM_REBUILD);
1290 	}
1291 
1292 	new_dp.f = choose_lookup_fn(da);
1293 	new_dp.arg = new_dxr;
1294 	if (fib_set_datapath_ptr(dxr->fd, &new_dp)) {
1295 		fib_set_algo_ptr(dxr->fd, new_dxr);
1296 		fib_epoch_call(epoch_dxr_destroy, &dxr->epoch_ctx);
1297 		return (FLM_SUCCESS);
1298 	}
1299 
1300 	FIB_PRINTF(LOG_NOTICE, dxr->fd, "fib_set_datapath_ptr() failed");
1301 	dxr_destroy(new_dxr);
1302 	return (FLM_REBUILD);
1303 }
1304 
1305 static uint8_t
1306 dxr_get_pref(const struct rib_rtable_info *rinfo)
1307 {
1308 
1309 	/* Below bsearch4 up to 10 prefixes. Always supersedes dpdk_lpm4. */
1310 	return (251);
1311 }
1312 
1313 SYSCTL_DECL(_net_route_algo);
1314 SYSCTL_NODE(_net_route_algo, OID_AUTO, dxr, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1315     "DXR tunables");
1316 
1317 static int
1318 sysctl_dxr_frag_limit(SYSCTL_HANDLER_ARGS)
1319 {
1320 	char buf[8];
1321 	int error, new, i;
1322 
1323 	snprintf(buf, sizeof(buf), "%d.%02d%%", V_frag_limit / 100,
1324 	    V_frag_limit % 100);
1325 	error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
1326 	if (error != 0 || req->newptr == NULL)
1327 		return (error);
1328 	if (!isdigit(*buf) && *buf != '.')
1329 		return (EINVAL);
1330 	for (i = 0, new = 0; isdigit(buf[i]) && i < sizeof(buf); i++)
1331 		new = new * 10 + buf[i] - '0';
1332 	new *= 100;
1333 	if (buf[i++] == '.') {
1334 		if (!isdigit(buf[i]))
1335 			return (EINVAL);
1336 		new += (buf[i++] - '0') * 10;
1337 		if (isdigit(buf[i]))
1338 			new += buf[i++] - '0';
1339 	}
1340 	if (new > 1000)
1341 		return (EINVAL);
1342 	V_frag_limit = new;
1343 	snprintf(buf, sizeof(buf), "%d.%02d%%", V_frag_limit / 100,
1344 	    V_frag_limit % 100);
1345 	return (0);
1346 }
1347 
1348 SYSCTL_PROC(_net_route_algo_dxr, OID_AUTO, frag_limit,
1349     CTLTYPE_STRING | CTLFLAG_RW | CTLFLAG_VNET,
1350     0, 0, sysctl_dxr_frag_limit, "A",
1351     "Fragmentation threshold to full rebuild");
1352 
1353 static struct fib_lookup_module fib_dxr_mod = {
1354 	.flm_name = "dxr",
1355 	.flm_family = AF_INET,
1356 	.flm_init_cb = dxr_init,
1357 	.flm_destroy_cb = dxr_destroy,
1358 	.flm_dump_rib_item_cb = dxr_dump_rib_item,
1359 	.flm_dump_end_cb = dxr_dump_end,
1360 	.flm_change_rib_item_cb = dxr_change_rib_item,
1361 	.flm_change_rib_items_cb = dxr_change_rib_batch,
1362 	.flm_get_pref = dxr_get_pref,
1363 };
1364 
1365 static int
1366 dxr_modevent(module_t mod, int type, void *unused)
1367 {
1368 	int error;
1369 
1370 	switch (type) {
1371 	case MOD_LOAD:
1372 		chunk_zone = uma_zcreate("dxr chunk", sizeof(struct chunk_desc),
1373 		    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1374 		trie_zone = uma_zcreate("dxr trie", sizeof(struct trie_desc),
1375 		    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
1376 		fib_module_register(&fib_dxr_mod);
1377 		return(0);
1378 	case MOD_UNLOAD:
1379 		error = fib_module_unregister(&fib_dxr_mod);
1380 		if (error)
1381 			return (error);
1382 		uma_zdestroy(chunk_zone);
1383 		uma_zdestroy(trie_zone);
1384 		return(0);
1385 	default:
1386 		return(EOPNOTSUPP);
1387 	}
1388 }
1389 
1390 static moduledata_t dxr_mod = {"fib_dxr", dxr_modevent, 0};
1391 
1392 DECLARE_MODULE(fib_dxr, dxr_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
1393 MODULE_VERSION(fib_dxr, 1);
1394