summaryrefslogtreecommitdiffstats
path: root/zebra/label_manager.c
blob: 2634a333eec2f233a1daabd9587abebf0dfc2e72 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
/*
 * Label Manager for FRR
 *
 * Copyright (C) 2017 by Bingen Eguzkitza,
 *                       Volta Networks Inc.
 *
 * This file is part of FRRouting (FRR)
 *
 * FRR is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * FRR is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>

#include "lib/log.h"
#include "lib/memory.h"
#include "lib/mpls.h"
#include "lib/network.h"
#include "lib/stream.h"
#include "lib/zclient.h"
#include "lib/libfrr.h"

//#include "zebra/zserv.h"
#include "zebra/zebra_router.h"
#include "zebra/label_manager.h"
#include "zebra/zebra_errors.h"
#include "zebra/zapi_msg.h"
#include "zebra/debug.h"

#define CONNECTION_DELAY 5

struct label_manager lbl_mgr;

DEFINE_MGROUP(LBL_MGR, "Label Manager");
DEFINE_MTYPE_STATIC(LBL_MGR, LM_CHUNK, "Label Manager Chunk");

/* define hooks for the basic API, so that it can be specialized or served
 * externally
 */

DEFINE_HOOK(lm_client_connect, (struct zserv *client, vrf_id_t vrf_id),
	    (client, vrf_id));
DEFINE_HOOK(lm_client_disconnect, (struct zserv *client), (client));
DEFINE_HOOK(lm_get_chunk,
	     (struct label_manager_chunk * *lmc, struct zserv *client,
	      uint8_t keep, uint32_t size, uint32_t base, vrf_id_t vrf_id),
	     (lmc, client, keep, size, base, vrf_id));
DEFINE_HOOK(lm_release_chunk,
	     (struct zserv *client, uint32_t start, uint32_t end),
	     (client, start, end));
DEFINE_HOOK(lm_cbs_inited, (), ());

/* define wrappers to be called in zapi_msg.c (as hooks must be called in
 * source file where they were defined)
 */
void lm_client_connect_call(struct zserv *client, vrf_id_t vrf_id)
{
	hook_call(lm_client_connect, client, vrf_id);
}
void lm_get_chunk_call(struct label_manager_chunk **lmc, struct zserv *client,
		       uint8_t keep, uint32_t size, uint32_t base,
		       vrf_id_t vrf_id)
{
	hook_call(lm_get_chunk, lmc, client, keep, size, base, vrf_id);
}
void lm_release_chunk_call(struct zserv *client, uint32_t start, uint32_t end)
{
	hook_call(lm_release_chunk, client, start, end);
}

/* forward declarations of the static functions to be used for some hooks */
static int label_manager_connect(struct zserv *client, vrf_id_t vrf_id);
static int label_manager_disconnect(struct zserv *client);
static int label_manager_get_chunk(struct label_manager_chunk **lmc,
				   struct zserv *client, uint8_t keep,
				   uint32_t size, uint32_t base,
				   vrf_id_t vrf_id);
static int label_manager_release_label_chunk(struct zserv *client,
					     uint32_t start, uint32_t end);

void delete_label_chunk(void *val)
{
	XFREE(MTYPE_LM_CHUNK, val);
}

/**
 * Release label chunks from a client.
 *
 * Called on client disconnection or reconnection. It only releases chunks
 * with empty keep value.
 *
 * @param proto Daemon protocol of client, to identify the owner
 * @param instance Instance, to identify the owner
 * @return Number of chunks released
 */
int release_daemon_label_chunks(struct zserv *client)
{
	struct listnode *node;
	struct label_manager_chunk *lmc;
	int count = 0;
	int ret;

	if (IS_ZEBRA_DEBUG_PACKET)
		zlog_debug("%s: Releasing chunks for client proto %s, instance %d, session %u",
			   __func__, zebra_route_string(client->proto),
			   client->instance, client->session_id);

	for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
		if (lmc->proto == client->proto &&
		    lmc->instance == client->instance &&
		    lmc->session_id == client->session_id && lmc->keep == 0) {
			ret = release_label_chunk(lmc->proto, lmc->instance,
						  lmc->session_id,
						  lmc->start, lmc->end);
			if (ret == 0)
				count++;
		}
	}

	if (IS_ZEBRA_DEBUG_PACKET)
		zlog_debug("%s: Released %d label chunks", __func__, count);

	return count;
}

int lm_client_disconnect_cb(struct zserv *client)
{
	hook_call(lm_client_disconnect, client);
	return 0;
}

void lm_hooks_register(void)
{
	hook_register(lm_client_connect, label_manager_connect);
	hook_register(lm_client_disconnect, label_manager_disconnect);
	hook_register(lm_get_chunk, label_manager_get_chunk);
	hook_register(lm_release_chunk, label_manager_release_label_chunk);
}
void lm_hooks_unregister(void)
{
	hook_unregister(lm_client_connect, label_manager_connect);
	hook_unregister(lm_client_disconnect, label_manager_disconnect);
	hook_unregister(lm_get_chunk, label_manager_get_chunk);
	hook_unregister(lm_release_chunk, label_manager_release_label_chunk);
}

/**
 * Init label manager (or proxy to an external one)
 */
void label_manager_init(void)
{
	lbl_mgr.lc_list = list_new();
	lbl_mgr.lc_list->del = delete_label_chunk;
	hook_register(zserv_client_close, lm_client_disconnect_cb);

	/* register default hooks for the label manager actions */
	lm_hooks_register();

	/* notify any external module that we are done */
	hook_call(lm_cbs_inited);
}

/* alloc and fill a label chunk */
struct label_manager_chunk *
create_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
		   uint8_t keep, uint32_t start, uint32_t end)
{
	/* alloc chunk, fill it and return it */
	struct label_manager_chunk *lmc =
		XCALLOC(MTYPE_LM_CHUNK, sizeof(struct label_manager_chunk));

	lmc->start = start;
	lmc->end = end;
	lmc->proto = proto;
	lmc->instance = instance;
	lmc->session_id = session_id;
	lmc->keep = keep;

	return lmc;
}

/* attempt to get a specific label chunk */
static struct label_manager_chunk *
assign_specific_label_chunk(uint8_t proto, unsigned short instance,
			    uint32_t session_id, uint8_t keep, uint32_t size,
			    uint32_t base)
{
	struct label_manager_chunk *lmc;
	struct listnode *node, *next = NULL;
	struct listnode *first_node = NULL;
	struct listnode *last_node = NULL;
	struct listnode *insert_node = NULL;

	/* precompute last label from base and size */
	uint32_t end = base + size - 1;

	/* sanities */
	if ((base < MPLS_LABEL_UNRESERVED_MIN)
	    || (end > MPLS_LABEL_UNRESERVED_MAX)) {
		zlog_err("Invalid LM request arguments: base: %u, size: %u",
			 base, size);
		return NULL;
	}

	/* Scan the existing chunks to see if the requested range of labels
	 * falls inside any of such chunks */
	for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {

		/* skip chunks for labels < base */
		if (base > lmc->end)
			continue;

		/* requested range is not covered by any existing, free chunk.
		 * Therefore, need to insert a chunk */
		if ((end < lmc->start) && !first_node) {
			insert_node = node;
			break;
		}

		if (!first_node)
			first_node = node;

		/* if chunk is used, cannot honor request */
		if (lmc->proto != NO_PROTO)
			return NULL;

		if (end <= lmc->end) {
			last_node = node;
			break;
		}
	}

	/* insert chunk between existing chunks */
	if (insert_node) {
		lmc = create_label_chunk(proto, instance, session_id, keep,
					 base, end);
		listnode_add_before(lbl_mgr.lc_list, insert_node, lmc);
		return lmc;
	}

	if (first_node) {
		/* get node past the last one, if there */
		if (last_node)
			last_node = listnextnode(last_node);

		/* delete node coming after the above chunk whose labels are
		 * included in the previous one */
		for (node = first_node; node && (node != last_node);
		     node = next) {
			struct label_manager_chunk *death;

			next = listnextnode(node);
			death = listgetdata(node);
			list_delete_node(lbl_mgr.lc_list, node);
			delete_label_chunk(death);
		}

		lmc = create_label_chunk(proto, instance, session_id, keep,
					 base, end);
		if (last_node)
			listnode_add_before(lbl_mgr.lc_list, last_node, lmc);
		else
			listnode_add(lbl_mgr.lc_list, lmc);

		return lmc;
	} else {
		/* create a new chunk past all the existing ones and link at
		 * tail */
		lmc = create_label_chunk(proto, instance, session_id, keep,
					 base, end);
		listnode_add(lbl_mgr.lc_list, lmc);
		return lmc;
	}
}

/**
 * Core function, assigns label chunks
 *
 * It first searches through the list to check if there's one available
 * (previously released). Otherwise it creates and assigns a new one
 *
 * @param proto Daemon protocol of client, to identify the owner
 * @param instance Instance, to identify the owner
 * @param keep If set, avoid garbage collection
 * @param size Size of the label chunk
 * @param base Desired starting label of the chunk; if MPLS_LABEL_BASE_ANY it does not apply
 * @return Pointer to the assigned label chunk, or NULL if the request could not be satisfied
 */
struct label_manager_chunk *
assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
		   uint8_t keep, uint32_t size, uint32_t base)
{
	struct label_manager_chunk *lmc;
	struct listnode *node;
	uint32_t prev_end = MPLS_LABEL_UNRESERVED_MIN;

	/* handle chunks request with a specific base label */
	if (base != MPLS_LABEL_BASE_ANY)
		return assign_specific_label_chunk(proto, instance, session_id,
						   keep, size, base);

	/* appease scan-build, who gets confused by the use of macros */
	assert(lbl_mgr.lc_list);

	/* first check if there's one available */
	for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
		if (lmc->proto == NO_PROTO
		    && lmc->end - lmc->start + 1 == size) {
			lmc->proto = proto;
			lmc->instance = instance;
			lmc->session_id = session_id;
			lmc->keep = keep;
			return lmc;
		}
		/* check if we hadve a "hole" behind us that we can squeeze into
		 */
		if ((lmc->start > prev_end) && (lmc->start - prev_end > size)) {
			lmc = create_label_chunk(proto, instance, session_id,
						 keep, prev_end + 1,
						 prev_end + size);
			listnode_add_before(lbl_mgr.lc_list, node, lmc);
			return lmc;
		}
		prev_end = lmc->end;
	}
	/* otherwise create a new one */
	uint32_t start_free;

	if (list_isempty(lbl_mgr.lc_list))
		start_free = MPLS_LABEL_UNRESERVED_MIN;
	else
		start_free = ((struct label_manager_chunk *)listgetdata(
				      listtail(lbl_mgr.lc_list)))
				     ->end
			     + 1;

	if (start_free > MPLS_LABEL_UNRESERVED_MAX - size + 1) {
		flog_err(EC_ZEBRA_LM_EXHAUSTED_LABELS,
			 "Reached max labels. Start: %u, size: %u", start_free,
			 size);
		return NULL;
	}

	/* create chunk and link at tail */
	lmc = create_label_chunk(proto, instance, session_id, keep, start_free,
				 start_free + size - 1);
	listnode_add(lbl_mgr.lc_list, lmc);
	return lmc;
}

/**
 * Release label chunks from a client.
 *
 * Called on client disconnection or reconnection. It only releases chunks
 * with empty keep value.
 *
 * @param client Client zapi session
 * @param start First label of the chunk
 * @param end Last label of the chunk
 * @return 0 on success
 */
static int label_manager_release_label_chunk(struct zserv *client,
					     uint32_t start, uint32_t end)
{
	return release_label_chunk(client->proto, client->instance,
				   client->session_id, start, end);
}

/**
 * Core function, release no longer used label chunks
 *
 * @param proto Daemon protocol of client, to identify the owner
 * @param instance Instance, to identify the owner
 * @param session_id Zclient session ID, to identify the zclient session
 * @param start First label of the chunk
 * @param end Last label of the chunk
 * @return 0 on success, -1 otherwise
 */
int release_label_chunk(uint8_t proto, unsigned short instance,
			uint32_t session_id, uint32_t start, uint32_t end)
{
	struct listnode *node;
	struct label_manager_chunk *lmc;
	int ret = -1;

	/* check that size matches */
	if (IS_ZEBRA_DEBUG_PACKET)
		zlog_debug("Releasing label chunk: %u - %u", start, end);
	/* find chunk and disown */
	for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
		if (lmc->start != start)
			continue;
		if (lmc->end != end)
			continue;
		if (lmc->proto != proto || lmc->instance != instance ||
		    lmc->session_id != session_id) {
			flog_err(EC_ZEBRA_LM_DAEMON_MISMATCH,
				 "%s: Daemon mismatch!!", __func__);
			continue;
		}
		lmc->proto = NO_PROTO;
		lmc->instance = 0;
		lmc->session_id = 0;
		lmc->keep = 0;
		ret = 0;
		break;
	}
	if (ret != 0)
		flog_err(EC_ZEBRA_LM_UNRELEASED_CHUNK,
			 "%s: Label chunk not released!!", __func__);

	return ret;
}

/* default functions to be called on hooks  */
static int label_manager_connect(struct zserv *client, vrf_id_t vrf_id)
{
	/*
	 * Release previous labels of same protocol and instance.
	 * This is done in case it restarted from an unexpected shutdown.
	 */
	release_daemon_label_chunks(client);
	return zsend_label_manager_connect_response(client, vrf_id, 0);
}
static int label_manager_disconnect(struct zserv *client)
{
	release_daemon_label_chunks(client);
	return 0;
}
static int label_manager_get_chunk(struct label_manager_chunk **lmc,
				   struct zserv *client, uint8_t keep,
				   uint32_t size, uint32_t base,
				   vrf_id_t vrf_id)
{
	*lmc = assign_label_chunk(client->proto, client->instance,
				  client->session_id, keep, size, base);
	return lm_get_chunk_response(*lmc, client, vrf_id);
}

/* Respond to a connect request */
int lm_client_connect_response(uint8_t proto, uint16_t instance,
			       uint32_t session_id, vrf_id_t vrf_id,
			       uint8_t result)
{
	struct zserv *client = zserv_find_client_session(proto, instance,
							 session_id);
	if (!client) {
		zlog_err("%s: could not find client for daemon %s instance %u session %u",
			 __func__, zebra_route_string(proto), instance,
			 session_id);
		return 1;
	}
	return zsend_label_manager_connect_response(client, vrf_id, result);
}

/* Respond to a get_chunk request */
int lm_get_chunk_response(struct label_manager_chunk *lmc, struct zserv *client,
			  vrf_id_t vrf_id)
{
	if (!lmc)
		flog_err(EC_ZEBRA_LM_CANNOT_ASSIGN_CHUNK,
			 "Unable to assign Label Chunk to %s instance %u",
			 zebra_route_string(client->proto), client->instance);
	else if (IS_ZEBRA_DEBUG_PACKET)
		zlog_debug("Assigned Label Chunk %u - %u to %s instance %u",
			   lmc->start, lmc->end,
			   zebra_route_string(client->proto), client->instance);

	return zsend_assign_label_chunk_response(client, vrf_id, lmc);
}

void label_manager_close(void)
{
	list_delete(&lbl_mgr.lc_list);
}