xref: /openbmc/linux/net/802/mrp.c (revision e3b9f1e8)
1 /*
2  *	IEEE 802.1Q Multiple Registration Protocol (MRP)
3  *
4  *	Copyright (c) 2012 Massachusetts Institute of Technology
5  *
6  *	Adapted from code in net/802/garp.c
7  *	Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
8  *
9  *	This program is free software; you can redistribute it and/or
10  *	modify it under the terms of the GNU General Public License
11  *	version 2 as published by the Free Software Foundation.
12  */
13 #include <linux/kernel.h>
14 #include <linux/timer.h>
15 #include <linux/skbuff.h>
16 #include <linux/netdevice.h>
17 #include <linux/etherdevice.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
21 #include <net/mrp.h>
22 #include <asm/unaligned.h>
23 
24 static unsigned int mrp_join_time __read_mostly = 200;
25 module_param(mrp_join_time, uint, 0644);
26 MODULE_PARM_DESC(mrp_join_time, "Join time in ms (default 200ms)");
27 
28 static unsigned int mrp_periodic_time __read_mostly = 1000;
29 module_param(mrp_periodic_time, uint, 0644);
30 MODULE_PARM_DESC(mrp_periodic_time, "Periodic time in ms (default 1s)");
31 
32 MODULE_LICENSE("GPL");
33 
34 static const u8
35 mrp_applicant_state_table[MRP_APPLICANT_MAX + 1][MRP_EVENT_MAX + 1] = {
36 	[MRP_APPLICANT_VO] = {
37 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
38 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VP,
39 		[MRP_EVENT_LV]		= MRP_APPLICANT_VO,
40 		[MRP_EVENT_TX]		= MRP_APPLICANT_VO,
41 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VO,
42 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AO,
43 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VO,
44 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VO,
45 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VO,
46 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
47 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
48 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
49 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VO,
50 	},
51 	[MRP_APPLICANT_VP] = {
52 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
53 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VP,
54 		[MRP_EVENT_LV]		= MRP_APPLICANT_VO,
55 		[MRP_EVENT_TX]		= MRP_APPLICANT_AA,
56 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VP,
57 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AP,
58 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VP,
59 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VP,
60 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VP,
61 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
62 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
63 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
64 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VP,
65 	},
66 	[MRP_APPLICANT_VN] = {
67 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
68 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VN,
69 		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
70 		[MRP_EVENT_TX]		= MRP_APPLICANT_AN,
71 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VN,
72 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_VN,
73 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VN,
74 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VN,
75 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VN,
76 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VN,
77 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VN,
78 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VN,
79 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VN,
80 	},
81 	[MRP_APPLICANT_AN] = {
82 		[MRP_EVENT_NEW]		= MRP_APPLICANT_AN,
83 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AN,
84 		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
85 		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
86 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AN,
87 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AN,
88 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AN,
89 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AN,
90 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AN,
91 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VN,
92 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VN,
93 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VN,
94 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AN,
95 	},
96 	[MRP_APPLICANT_AA] = {
97 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
98 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AA,
99 		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
100 		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
101 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AA,
102 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QA,
103 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AA,
104 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AA,
105 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AA,
106 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
107 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
108 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
109 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AA,
110 	},
111 	[MRP_APPLICANT_QA] = {
112 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
113 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QA,
114 		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
115 		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
116 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QA,
117 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QA,
118 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QA,
119 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AA,
120 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AA,
121 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
122 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
123 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
124 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AA,
125 	},
126 	[MRP_APPLICANT_LA] = {
127 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
128 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AA,
129 		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
130 		[MRP_EVENT_TX]		= MRP_APPLICANT_VO,
131 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_LA,
132 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_LA,
133 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_LA,
134 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_LA,
135 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_LA,
136 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_LA,
137 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_LA,
138 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_LA,
139 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_LA,
140 	},
141 	[MRP_APPLICANT_AO] = {
142 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
143 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AP,
144 		[MRP_EVENT_LV]		= MRP_APPLICANT_AO,
145 		[MRP_EVENT_TX]		= MRP_APPLICANT_AO,
146 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AO,
147 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QO,
148 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AO,
149 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AO,
150 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AO,
151 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
152 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
153 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
154 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AO,
155 	},
156 	[MRP_APPLICANT_QO] = {
157 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
158 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QP,
159 		[MRP_EVENT_LV]		= MRP_APPLICANT_QO,
160 		[MRP_EVENT_TX]		= MRP_APPLICANT_QO,
161 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QO,
162 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QO,
163 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QO,
164 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AO,
165 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AO,
166 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
167 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
168 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
169 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_QO,
170 	},
171 	[MRP_APPLICANT_AP] = {
172 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
173 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AP,
174 		[MRP_EVENT_LV]		= MRP_APPLICANT_AO,
175 		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
176 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AP,
177 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QP,
178 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AP,
179 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AP,
180 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AP,
181 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
182 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
183 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
184 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AP,
185 	},
186 	[MRP_APPLICANT_QP] = {
187 		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
188 		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QP,
189 		[MRP_EVENT_LV]		= MRP_APPLICANT_QO,
190 		[MRP_EVENT_TX]		= MRP_APPLICANT_QP,
191 		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QP,
192 		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QP,
193 		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QP,
194 		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AP,
195 		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AP,
196 		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
197 		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
198 		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
199 		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AP,
200 	},
201 };
202 
203 static const u8
204 mrp_tx_action_table[MRP_APPLICANT_MAX + 1] = {
205 	[MRP_APPLICANT_VO] = MRP_TX_ACTION_S_IN_OPTIONAL,
206 	[MRP_APPLICANT_VP] = MRP_TX_ACTION_S_JOIN_IN,
207 	[MRP_APPLICANT_VN] = MRP_TX_ACTION_S_NEW,
208 	[MRP_APPLICANT_AN] = MRP_TX_ACTION_S_NEW,
209 	[MRP_APPLICANT_AA] = MRP_TX_ACTION_S_JOIN_IN,
210 	[MRP_APPLICANT_QA] = MRP_TX_ACTION_S_JOIN_IN_OPTIONAL,
211 	[MRP_APPLICANT_LA] = MRP_TX_ACTION_S_LV,
212 	[MRP_APPLICANT_AO] = MRP_TX_ACTION_S_IN_OPTIONAL,
213 	[MRP_APPLICANT_QO] = MRP_TX_ACTION_S_IN_OPTIONAL,
214 	[MRP_APPLICANT_AP] = MRP_TX_ACTION_S_JOIN_IN,
215 	[MRP_APPLICANT_QP] = MRP_TX_ACTION_S_IN_OPTIONAL,
216 };
217 
218 static void mrp_attrvalue_inc(void *value, u8 len)
219 {
220 	u8 *v = (u8 *)value;
221 
222 	/* Add 1 to the last byte. If it becomes zero,
223 	 * go to the previous byte and repeat.
224 	 */
225 	while (len > 0 && !++v[--len])
226 		;
227 }
228 
229 static int mrp_attr_cmp(const struct mrp_attr *attr,
230 			 const void *value, u8 len, u8 type)
231 {
232 	if (attr->type != type)
233 		return attr->type - type;
234 	if (attr->len != len)
235 		return attr->len - len;
236 	return memcmp(attr->value, value, len);
237 }
238 
239 static struct mrp_attr *mrp_attr_lookup(const struct mrp_applicant *app,
240 					const void *value, u8 len, u8 type)
241 {
242 	struct rb_node *parent = app->mad.rb_node;
243 	struct mrp_attr *attr;
244 	int d;
245 
246 	while (parent) {
247 		attr = rb_entry(parent, struct mrp_attr, node);
248 		d = mrp_attr_cmp(attr, value, len, type);
249 		if (d > 0)
250 			parent = parent->rb_left;
251 		else if (d < 0)
252 			parent = parent->rb_right;
253 		else
254 			return attr;
255 	}
256 	return NULL;
257 }
258 
259 static struct mrp_attr *mrp_attr_create(struct mrp_applicant *app,
260 					const void *value, u8 len, u8 type)
261 {
262 	struct rb_node *parent = NULL, **p = &app->mad.rb_node;
263 	struct mrp_attr *attr;
264 	int d;
265 
266 	while (*p) {
267 		parent = *p;
268 		attr = rb_entry(parent, struct mrp_attr, node);
269 		d = mrp_attr_cmp(attr, value, len, type);
270 		if (d > 0)
271 			p = &parent->rb_left;
272 		else if (d < 0)
273 			p = &parent->rb_right;
274 		else {
275 			/* The attribute already exists; re-use it. */
276 			return attr;
277 		}
278 	}
279 	attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
280 	if (!attr)
281 		return attr;
282 	attr->state = MRP_APPLICANT_VO;
283 	attr->type  = type;
284 	attr->len   = len;
285 	memcpy(attr->value, value, len);
286 
287 	rb_link_node(&attr->node, parent, p);
288 	rb_insert_color(&attr->node, &app->mad);
289 	return attr;
290 }
291 
292 static void mrp_attr_destroy(struct mrp_applicant *app, struct mrp_attr *attr)
293 {
294 	rb_erase(&attr->node, &app->mad);
295 	kfree(attr);
296 }
297 
298 static int mrp_pdu_init(struct mrp_applicant *app)
299 {
300 	struct sk_buff *skb;
301 	struct mrp_pdu_hdr *ph;
302 
303 	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
304 			GFP_ATOMIC);
305 	if (!skb)
306 		return -ENOMEM;
307 
308 	skb->dev = app->dev;
309 	skb->protocol = app->app->pkttype.type;
310 	skb_reserve(skb, LL_RESERVED_SPACE(app->dev));
311 	skb_reset_network_header(skb);
312 	skb_reset_transport_header(skb);
313 
314 	ph = __skb_put(skb, sizeof(*ph));
315 	ph->version = app->app->version;
316 
317 	app->pdu = skb;
318 	return 0;
319 }
320 
321 static int mrp_pdu_append_end_mark(struct mrp_applicant *app)
322 {
323 	__be16 *endmark;
324 
325 	if (skb_tailroom(app->pdu) < sizeof(*endmark))
326 		return -1;
327 	endmark = __skb_put(app->pdu, sizeof(*endmark));
328 	put_unaligned(MRP_END_MARK, endmark);
329 	return 0;
330 }
331 
332 static void mrp_pdu_queue(struct mrp_applicant *app)
333 {
334 	if (!app->pdu)
335 		return;
336 
337 	if (mrp_cb(app->pdu)->mh)
338 		mrp_pdu_append_end_mark(app);
339 	mrp_pdu_append_end_mark(app);
340 
341 	dev_hard_header(app->pdu, app->dev, ntohs(app->app->pkttype.type),
342 			app->app->group_address, app->dev->dev_addr,
343 			app->pdu->len);
344 
345 	skb_queue_tail(&app->queue, app->pdu);
346 	app->pdu = NULL;
347 }
348 
349 static void mrp_queue_xmit(struct mrp_applicant *app)
350 {
351 	struct sk_buff *skb;
352 
353 	while ((skb = skb_dequeue(&app->queue)))
354 		dev_queue_xmit(skb);
355 }
356 
357 static int mrp_pdu_append_msg_hdr(struct mrp_applicant *app,
358 				  u8 attrtype, u8 attrlen)
359 {
360 	struct mrp_msg_hdr *mh;
361 
362 	if (mrp_cb(app->pdu)->mh) {
363 		if (mrp_pdu_append_end_mark(app) < 0)
364 			return -1;
365 		mrp_cb(app->pdu)->mh = NULL;
366 		mrp_cb(app->pdu)->vah = NULL;
367 	}
368 
369 	if (skb_tailroom(app->pdu) < sizeof(*mh))
370 		return -1;
371 	mh = __skb_put(app->pdu, sizeof(*mh));
372 	mh->attrtype = attrtype;
373 	mh->attrlen = attrlen;
374 	mrp_cb(app->pdu)->mh = mh;
375 	return 0;
376 }
377 
378 static int mrp_pdu_append_vecattr_hdr(struct mrp_applicant *app,
379 				      const void *firstattrvalue, u8 attrlen)
380 {
381 	struct mrp_vecattr_hdr *vah;
382 
383 	if (skb_tailroom(app->pdu) < sizeof(*vah) + attrlen)
384 		return -1;
385 	vah = __skb_put(app->pdu, sizeof(*vah) + attrlen);
386 	put_unaligned(0, &vah->lenflags);
387 	memcpy(vah->firstattrvalue, firstattrvalue, attrlen);
388 	mrp_cb(app->pdu)->vah = vah;
389 	memcpy(mrp_cb(app->pdu)->attrvalue, firstattrvalue, attrlen);
390 	return 0;
391 }
392 
393 static int mrp_pdu_append_vecattr_event(struct mrp_applicant *app,
394 					const struct mrp_attr *attr,
395 					enum mrp_vecattr_event vaevent)
396 {
397 	u16 len, pos;
398 	u8 *vaevents;
399 	int err;
400 again:
401 	if (!app->pdu) {
402 		err = mrp_pdu_init(app);
403 		if (err < 0)
404 			return err;
405 	}
406 
407 	/* If there is no Message header in the PDU, or the Message header is
408 	 * for a different attribute type, add an EndMark (if necessary) and a
409 	 * new Message header to the PDU.
410 	 */
411 	if (!mrp_cb(app->pdu)->mh ||
412 	    mrp_cb(app->pdu)->mh->attrtype != attr->type ||
413 	    mrp_cb(app->pdu)->mh->attrlen != attr->len) {
414 		if (mrp_pdu_append_msg_hdr(app, attr->type, attr->len) < 0)
415 			goto queue;
416 	}
417 
418 	/* If there is no VectorAttribute header for this Message in the PDU,
419 	 * or this attribute's value does not sequentially follow the previous
420 	 * attribute's value, add a new VectorAttribute header to the PDU.
421 	 */
422 	if (!mrp_cb(app->pdu)->vah ||
423 	    memcmp(mrp_cb(app->pdu)->attrvalue, attr->value, attr->len)) {
424 		if (mrp_pdu_append_vecattr_hdr(app, attr->value, attr->len) < 0)
425 			goto queue;
426 	}
427 
428 	len = be16_to_cpu(get_unaligned(&mrp_cb(app->pdu)->vah->lenflags));
429 	pos = len % 3;
430 
431 	/* Events are packed into Vectors in the PDU, three to a byte. Add a
432 	 * byte to the end of the Vector if necessary.
433 	 */
434 	if (!pos) {
435 		if (skb_tailroom(app->pdu) < sizeof(u8))
436 			goto queue;
437 		vaevents = __skb_put(app->pdu, sizeof(u8));
438 	} else {
439 		vaevents = (u8 *)(skb_tail_pointer(app->pdu) - sizeof(u8));
440 	}
441 
442 	switch (pos) {
443 	case 0:
444 		*vaevents = vaevent * (__MRP_VECATTR_EVENT_MAX *
445 				       __MRP_VECATTR_EVENT_MAX);
446 		break;
447 	case 1:
448 		*vaevents += vaevent * __MRP_VECATTR_EVENT_MAX;
449 		break;
450 	case 2:
451 		*vaevents += vaevent;
452 		break;
453 	default:
454 		WARN_ON(1);
455 	}
456 
457 	/* Increment the length of the VectorAttribute in the PDU, as well as
458 	 * the value of the next attribute that would continue its Vector.
459 	 */
460 	put_unaligned(cpu_to_be16(++len), &mrp_cb(app->pdu)->vah->lenflags);
461 	mrp_attrvalue_inc(mrp_cb(app->pdu)->attrvalue, attr->len);
462 
463 	return 0;
464 
465 queue:
466 	mrp_pdu_queue(app);
467 	goto again;
468 }
469 
470 static void mrp_attr_event(struct mrp_applicant *app,
471 			   struct mrp_attr *attr, enum mrp_event event)
472 {
473 	enum mrp_applicant_state state;
474 
475 	state = mrp_applicant_state_table[attr->state][event];
476 	if (state == MRP_APPLICANT_INVALID) {
477 		WARN_ON(1);
478 		return;
479 	}
480 
481 	if (event == MRP_EVENT_TX) {
482 		/* When appending the attribute fails, don't update its state
483 		 * in order to retry at the next TX event.
484 		 */
485 
486 		switch (mrp_tx_action_table[attr->state]) {
487 		case MRP_TX_ACTION_NONE:
488 		case MRP_TX_ACTION_S_JOIN_IN_OPTIONAL:
489 		case MRP_TX_ACTION_S_IN_OPTIONAL:
490 			break;
491 		case MRP_TX_ACTION_S_NEW:
492 			if (mrp_pdu_append_vecattr_event(
493 				    app, attr, MRP_VECATTR_EVENT_NEW) < 0)
494 				return;
495 			break;
496 		case MRP_TX_ACTION_S_JOIN_IN:
497 			if (mrp_pdu_append_vecattr_event(
498 				    app, attr, MRP_VECATTR_EVENT_JOIN_IN) < 0)
499 				return;
500 			break;
501 		case MRP_TX_ACTION_S_LV:
502 			if (mrp_pdu_append_vecattr_event(
503 				    app, attr, MRP_VECATTR_EVENT_LV) < 0)
504 				return;
505 			/* As a pure applicant, sending a leave message
506 			 * implies that the attribute was unregistered and
507 			 * can be destroyed.
508 			 */
509 			mrp_attr_destroy(app, attr);
510 			return;
511 		default:
512 			WARN_ON(1);
513 		}
514 	}
515 
516 	attr->state = state;
517 }
518 
519 int mrp_request_join(const struct net_device *dev,
520 		     const struct mrp_application *appl,
521 		     const void *value, u8 len, u8 type)
522 {
523 	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
524 	struct mrp_applicant *app = rtnl_dereference(
525 		port->applicants[appl->type]);
526 	struct mrp_attr *attr;
527 
528 	if (sizeof(struct mrp_skb_cb) + len >
529 	    FIELD_SIZEOF(struct sk_buff, cb))
530 		return -ENOMEM;
531 
532 	spin_lock_bh(&app->lock);
533 	attr = mrp_attr_create(app, value, len, type);
534 	if (!attr) {
535 		spin_unlock_bh(&app->lock);
536 		return -ENOMEM;
537 	}
538 	mrp_attr_event(app, attr, MRP_EVENT_JOIN);
539 	spin_unlock_bh(&app->lock);
540 	return 0;
541 }
542 EXPORT_SYMBOL_GPL(mrp_request_join);
543 
544 void mrp_request_leave(const struct net_device *dev,
545 		       const struct mrp_application *appl,
546 		       const void *value, u8 len, u8 type)
547 {
548 	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
549 	struct mrp_applicant *app = rtnl_dereference(
550 		port->applicants[appl->type]);
551 	struct mrp_attr *attr;
552 
553 	if (sizeof(struct mrp_skb_cb) + len >
554 	    FIELD_SIZEOF(struct sk_buff, cb))
555 		return;
556 
557 	spin_lock_bh(&app->lock);
558 	attr = mrp_attr_lookup(app, value, len, type);
559 	if (!attr) {
560 		spin_unlock_bh(&app->lock);
561 		return;
562 	}
563 	mrp_attr_event(app, attr, MRP_EVENT_LV);
564 	spin_unlock_bh(&app->lock);
565 }
566 EXPORT_SYMBOL_GPL(mrp_request_leave);
567 
568 static void mrp_mad_event(struct mrp_applicant *app, enum mrp_event event)
569 {
570 	struct rb_node *node, *next;
571 	struct mrp_attr *attr;
572 
573 	for (node = rb_first(&app->mad);
574 	     next = node ? rb_next(node) : NULL, node != NULL;
575 	     node = next) {
576 		attr = rb_entry(node, struct mrp_attr, node);
577 		mrp_attr_event(app, attr, event);
578 	}
579 }
580 
581 static void mrp_join_timer_arm(struct mrp_applicant *app)
582 {
583 	unsigned long delay;
584 
585 	delay = (u64)msecs_to_jiffies(mrp_join_time) * prandom_u32() >> 32;
586 	mod_timer(&app->join_timer, jiffies + delay);
587 }
588 
589 static void mrp_join_timer(struct timer_list *t)
590 {
591 	struct mrp_applicant *app = from_timer(app, t, join_timer);
592 
593 	spin_lock(&app->lock);
594 	mrp_mad_event(app, MRP_EVENT_TX);
595 	mrp_pdu_queue(app);
596 	spin_unlock(&app->lock);
597 
598 	mrp_queue_xmit(app);
599 	mrp_join_timer_arm(app);
600 }
601 
602 static void mrp_periodic_timer_arm(struct mrp_applicant *app)
603 {
604 	mod_timer(&app->periodic_timer,
605 		  jiffies + msecs_to_jiffies(mrp_periodic_time));
606 }
607 
608 static void mrp_periodic_timer(struct timer_list *t)
609 {
610 	struct mrp_applicant *app = from_timer(app, t, periodic_timer);
611 
612 	spin_lock(&app->lock);
613 	mrp_mad_event(app, MRP_EVENT_PERIODIC);
614 	mrp_pdu_queue(app);
615 	spin_unlock(&app->lock);
616 
617 	mrp_periodic_timer_arm(app);
618 }
619 
620 static int mrp_pdu_parse_end_mark(struct sk_buff *skb, int *offset)
621 {
622 	__be16 endmark;
623 
624 	if (skb_copy_bits(skb, *offset, &endmark, sizeof(endmark)) < 0)
625 		return -1;
626 	if (endmark == MRP_END_MARK) {
627 		*offset += sizeof(endmark);
628 		return -1;
629 	}
630 	return 0;
631 }
632 
633 static void mrp_pdu_parse_vecattr_event(struct mrp_applicant *app,
634 					struct sk_buff *skb,
635 					enum mrp_vecattr_event vaevent)
636 {
637 	struct mrp_attr *attr;
638 	enum mrp_event event;
639 
640 	attr = mrp_attr_lookup(app, mrp_cb(skb)->attrvalue,
641 			       mrp_cb(skb)->mh->attrlen,
642 			       mrp_cb(skb)->mh->attrtype);
643 	if (attr == NULL)
644 		return;
645 
646 	switch (vaevent) {
647 	case MRP_VECATTR_EVENT_NEW:
648 		event = MRP_EVENT_R_NEW;
649 		break;
650 	case MRP_VECATTR_EVENT_JOIN_IN:
651 		event = MRP_EVENT_R_JOIN_IN;
652 		break;
653 	case MRP_VECATTR_EVENT_IN:
654 		event = MRP_EVENT_R_IN;
655 		break;
656 	case MRP_VECATTR_EVENT_JOIN_MT:
657 		event = MRP_EVENT_R_JOIN_MT;
658 		break;
659 	case MRP_VECATTR_EVENT_MT:
660 		event = MRP_EVENT_R_MT;
661 		break;
662 	case MRP_VECATTR_EVENT_LV:
663 		event = MRP_EVENT_R_LV;
664 		break;
665 	default:
666 		return;
667 	}
668 
669 	mrp_attr_event(app, attr, event);
670 }
671 
672 static int mrp_pdu_parse_vecattr(struct mrp_applicant *app,
673 				 struct sk_buff *skb, int *offset)
674 {
675 	struct mrp_vecattr_hdr _vah;
676 	u16 valen;
677 	u8 vaevents, vaevent;
678 
679 	mrp_cb(skb)->vah = skb_header_pointer(skb, *offset, sizeof(_vah),
680 					      &_vah);
681 	if (!mrp_cb(skb)->vah)
682 		return -1;
683 	*offset += sizeof(_vah);
684 
685 	if (get_unaligned(&mrp_cb(skb)->vah->lenflags) &
686 	    MRP_VECATTR_HDR_FLAG_LA)
687 		mrp_mad_event(app, MRP_EVENT_R_LA);
688 	valen = be16_to_cpu(get_unaligned(&mrp_cb(skb)->vah->lenflags) &
689 			    MRP_VECATTR_HDR_LEN_MASK);
690 
691 	/* The VectorAttribute structure in a PDU carries event information
692 	 * about one or more attributes having consecutive values. Only the
693 	 * value for the first attribute is contained in the structure. So
694 	 * we make a copy of that value, and then increment it each time we
695 	 * advance to the next event in its Vector.
696 	 */
697 	if (sizeof(struct mrp_skb_cb) + mrp_cb(skb)->mh->attrlen >
698 	    FIELD_SIZEOF(struct sk_buff, cb))
699 		return -1;
700 	if (skb_copy_bits(skb, *offset, mrp_cb(skb)->attrvalue,
701 			  mrp_cb(skb)->mh->attrlen) < 0)
702 		return -1;
703 	*offset += mrp_cb(skb)->mh->attrlen;
704 
705 	/* In a VectorAttribute, the Vector contains events which are packed
706 	 * three to a byte. We process one byte of the Vector at a time.
707 	 */
708 	while (valen > 0) {
709 		if (skb_copy_bits(skb, *offset, &vaevents,
710 				  sizeof(vaevents)) < 0)
711 			return -1;
712 		*offset += sizeof(vaevents);
713 
714 		/* Extract and process the first event. */
715 		vaevent = vaevents / (__MRP_VECATTR_EVENT_MAX *
716 				      __MRP_VECATTR_EVENT_MAX);
717 		if (vaevent >= __MRP_VECATTR_EVENT_MAX) {
718 			/* The byte is malformed; stop processing. */
719 			return -1;
720 		}
721 		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
722 
723 		/* If present, extract and process the second event. */
724 		if (!--valen)
725 			break;
726 		mrp_attrvalue_inc(mrp_cb(skb)->attrvalue,
727 				  mrp_cb(skb)->mh->attrlen);
728 		vaevents %= (__MRP_VECATTR_EVENT_MAX *
729 			     __MRP_VECATTR_EVENT_MAX);
730 		vaevent = vaevents / __MRP_VECATTR_EVENT_MAX;
731 		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
732 
733 		/* If present, extract and process the third event. */
734 		if (!--valen)
735 			break;
736 		mrp_attrvalue_inc(mrp_cb(skb)->attrvalue,
737 				  mrp_cb(skb)->mh->attrlen);
738 		vaevents %= __MRP_VECATTR_EVENT_MAX;
739 		vaevent = vaevents;
740 		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
741 	}
742 	return 0;
743 }
744 
745 static int mrp_pdu_parse_msg(struct mrp_applicant *app, struct sk_buff *skb,
746 			     int *offset)
747 {
748 	struct mrp_msg_hdr _mh;
749 
750 	mrp_cb(skb)->mh = skb_header_pointer(skb, *offset, sizeof(_mh), &_mh);
751 	if (!mrp_cb(skb)->mh)
752 		return -1;
753 	*offset += sizeof(_mh);
754 
755 	if (mrp_cb(skb)->mh->attrtype == 0 ||
756 	    mrp_cb(skb)->mh->attrtype > app->app->maxattr ||
757 	    mrp_cb(skb)->mh->attrlen == 0)
758 		return -1;
759 
760 	while (skb->len > *offset) {
761 		if (mrp_pdu_parse_end_mark(skb, offset) < 0)
762 			break;
763 		if (mrp_pdu_parse_vecattr(app, skb, offset) < 0)
764 			return -1;
765 	}
766 	return 0;
767 }
768 
769 static int mrp_rcv(struct sk_buff *skb, struct net_device *dev,
770 		   struct packet_type *pt, struct net_device *orig_dev)
771 {
772 	struct mrp_application *appl = container_of(pt, struct mrp_application,
773 						    pkttype);
774 	struct mrp_port *port;
775 	struct mrp_applicant *app;
776 	struct mrp_pdu_hdr _ph;
777 	const struct mrp_pdu_hdr *ph;
778 	int offset = skb_network_offset(skb);
779 
780 	/* If the interface is in promiscuous mode, drop the packet if
781 	 * it was unicast to another host.
782 	 */
783 	if (unlikely(skb->pkt_type == PACKET_OTHERHOST))
784 		goto out;
785 	skb = skb_share_check(skb, GFP_ATOMIC);
786 	if (unlikely(!skb))
787 		goto out;
788 	port = rcu_dereference(dev->mrp_port);
789 	if (unlikely(!port))
790 		goto out;
791 	app = rcu_dereference(port->applicants[appl->type]);
792 	if (unlikely(!app))
793 		goto out;
794 
795 	ph = skb_header_pointer(skb, offset, sizeof(_ph), &_ph);
796 	if (!ph)
797 		goto out;
798 	offset += sizeof(_ph);
799 
800 	if (ph->version != app->app->version)
801 		goto out;
802 
803 	spin_lock(&app->lock);
804 	while (skb->len > offset) {
805 		if (mrp_pdu_parse_end_mark(skb, &offset) < 0)
806 			break;
807 		if (mrp_pdu_parse_msg(app, skb, &offset) < 0)
808 			break;
809 	}
810 	spin_unlock(&app->lock);
811 out:
812 	kfree_skb(skb);
813 	return 0;
814 }
815 
816 static int mrp_init_port(struct net_device *dev)
817 {
818 	struct mrp_port *port;
819 
820 	port = kzalloc(sizeof(*port), GFP_KERNEL);
821 	if (!port)
822 		return -ENOMEM;
823 	rcu_assign_pointer(dev->mrp_port, port);
824 	return 0;
825 }
826 
827 static void mrp_release_port(struct net_device *dev)
828 {
829 	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
830 	unsigned int i;
831 
832 	for (i = 0; i <= MRP_APPLICATION_MAX; i++) {
833 		if (rtnl_dereference(port->applicants[i]))
834 			return;
835 	}
836 	RCU_INIT_POINTER(dev->mrp_port, NULL);
837 	kfree_rcu(port, rcu);
838 }
839 
840 int mrp_init_applicant(struct net_device *dev, struct mrp_application *appl)
841 {
842 	struct mrp_applicant *app;
843 	int err;
844 
845 	ASSERT_RTNL();
846 
847 	if (!rtnl_dereference(dev->mrp_port)) {
848 		err = mrp_init_port(dev);
849 		if (err < 0)
850 			goto err1;
851 	}
852 
853 	err = -ENOMEM;
854 	app = kzalloc(sizeof(*app), GFP_KERNEL);
855 	if (!app)
856 		goto err2;
857 
858 	err = dev_mc_add(dev, appl->group_address);
859 	if (err < 0)
860 		goto err3;
861 
862 	app->dev = dev;
863 	app->app = appl;
864 	app->mad = RB_ROOT;
865 	spin_lock_init(&app->lock);
866 	skb_queue_head_init(&app->queue);
867 	rcu_assign_pointer(dev->mrp_port->applicants[appl->type], app);
868 	timer_setup(&app->join_timer, mrp_join_timer, 0);
869 	mrp_join_timer_arm(app);
870 	timer_setup(&app->periodic_timer, mrp_periodic_timer, 0);
871 	mrp_periodic_timer_arm(app);
872 	return 0;
873 
874 err3:
875 	kfree(app);
876 err2:
877 	mrp_release_port(dev);
878 err1:
879 	return err;
880 }
881 EXPORT_SYMBOL_GPL(mrp_init_applicant);
882 
883 void mrp_uninit_applicant(struct net_device *dev, struct mrp_application *appl)
884 {
885 	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
886 	struct mrp_applicant *app = rtnl_dereference(
887 		port->applicants[appl->type]);
888 
889 	ASSERT_RTNL();
890 
891 	RCU_INIT_POINTER(port->applicants[appl->type], NULL);
892 
893 	/* Delete timer and generate a final TX event to flush out
894 	 * all pending messages before the applicant is gone.
895 	 */
896 	del_timer_sync(&app->join_timer);
897 	del_timer_sync(&app->periodic_timer);
898 
899 	spin_lock_bh(&app->lock);
900 	mrp_mad_event(app, MRP_EVENT_TX);
901 	mrp_pdu_queue(app);
902 	spin_unlock_bh(&app->lock);
903 
904 	mrp_queue_xmit(app);
905 
906 	dev_mc_del(dev, appl->group_address);
907 	kfree_rcu(app, rcu);
908 	mrp_release_port(dev);
909 }
910 EXPORT_SYMBOL_GPL(mrp_uninit_applicant);
911 
912 int mrp_register_application(struct mrp_application *appl)
913 {
914 	appl->pkttype.func = mrp_rcv;
915 	dev_add_pack(&appl->pkttype);
916 	return 0;
917 }
918 EXPORT_SYMBOL_GPL(mrp_register_application);
919 
920 void mrp_unregister_application(struct mrp_application *appl)
921 {
922 	dev_remove_pack(&appl->pkttype);
923 }
924 EXPORT_SYMBOL_GPL(mrp_unregister_application);
925