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TOMOYO Linux Cross Reference
Linux/net/802/garp.c

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  1 /*
  2  *      IEEE 802.1D Generic Attribute Registration Protocol (GARP)
  3  *
  4  *      Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
  5  *
  6  *      This program is free software; you can redistribute it and/or
  7  *      modify it under the terms of the GNU General Public License
  8  *      version 2 as published by the Free Software Foundation.
  9  */
 10 #include <linux/kernel.h>
 11 #include <linux/timer.h>
 12 #include <linux/skbuff.h>
 13 #include <linux/netdevice.h>
 14 #include <linux/etherdevice.h>
 15 #include <linux/rtnetlink.h>
 16 #include <linux/llc.h>
 17 #include <linux/slab.h>
 18 #include <linux/module.h>
 19 #include <net/llc.h>
 20 #include <net/llc_pdu.h>
 21 #include <net/garp.h>
 22 #include <asm/unaligned.h>
 23 
 24 static unsigned int garp_join_time __read_mostly = 200;
 25 module_param(garp_join_time, uint, 0644);
 26 MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
 27 MODULE_LICENSE("GPL");
 28 
 29 static const struct garp_state_trans {
 30         u8      state;
 31         u8      action;
 32 } garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = {
 33         [GARP_APPLICANT_VA] = {
 34                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_AA,
 35                                                     .action = GARP_ACTION_S_JOIN_IN },
 36                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AA },
 37                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
 38                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
 39                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VA },
 40                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
 41                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
 42                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
 43         },
 44         [GARP_APPLICANT_AA] = {
 45                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_QA,
 46                                                     .action = GARP_ACTION_S_JOIN_IN },
 47                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QA },
 48                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
 49                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
 50                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VA },
 51                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
 52                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
 53                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
 54         },
 55         [GARP_APPLICANT_QA] = {
 56                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
 57                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QA },
 58                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
 59                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
 60                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
 61                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
 62                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
 63                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
 64         },
 65         [GARP_APPLICANT_LA] = {
 66                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_VO,
 67                                                     .action = GARP_ACTION_S_LEAVE_EMPTY },
 68                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_LA },
 69                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
 70                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_LA },
 71                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_LA },
 72                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
 73                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_VA },
 74                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
 75         },
 76         [GARP_APPLICANT_VP] = {
 77                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_AA,
 78                                                     .action = GARP_ACTION_S_JOIN_IN },
 79                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AP },
 80                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
 81                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
 82                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
 83                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
 84                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
 85                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_VO },
 86         },
 87         [GARP_APPLICANT_AP] = {
 88                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_QA,
 89                                                     .action = GARP_ACTION_S_JOIN_IN },
 90                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QP },
 91                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
 92                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
 93                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
 94                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
 95                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
 96                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_AO },
 97         },
 98         [GARP_APPLICANT_QP] = {
 99                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
100                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QP },
101                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
102                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
103                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
104                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
105                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
106                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_QO },
107         },
108         [GARP_APPLICANT_VO] = {
109                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
110                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AO },
111                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
112                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
113                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
114                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
115                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_VP },
116                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
117         },
118         [GARP_APPLICANT_AO] = {
119                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
120                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QO },
121                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
122                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
123                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
124                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
125                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_AP },
126                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
127         },
128         [GARP_APPLICANT_QO] = {
129                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
130                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QO },
131                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
132                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
133                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
134                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
135                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_QP },
136                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
137         },
138 };
139 
140 static int garp_attr_cmp(const struct garp_attr *attr,
141                          const void *data, u8 len, u8 type)
142 {
143         if (attr->type != type)
144                 return attr->type - type;
145         if (attr->dlen != len)
146                 return attr->dlen - len;
147         return memcmp(attr->data, data, len);
148 }
149 
150 static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app,
151                                           const void *data, u8 len, u8 type)
152 {
153         struct rb_node *parent = app->gid.rb_node;
154         struct garp_attr *attr;
155         int d;
156 
157         while (parent) {
158                 attr = rb_entry(parent, struct garp_attr, node);
159                 d = garp_attr_cmp(attr, data, len, type);
160                 if (d > 0)
161                         parent = parent->rb_left;
162                 else if (d < 0)
163                         parent = parent->rb_right;
164                 else
165                         return attr;
166         }
167         return NULL;
168 }
169 
170 static struct garp_attr *garp_attr_create(struct garp_applicant *app,
171                                           const void *data, u8 len, u8 type)
172 {
173         struct rb_node *parent = NULL, **p = &app->gid.rb_node;
174         struct garp_attr *attr;
175         int d;
176 
177         while (*p) {
178                 parent = *p;
179                 attr = rb_entry(parent, struct garp_attr, node);
180                 d = garp_attr_cmp(attr, data, len, type);
181                 if (d > 0)
182                         p = &parent->rb_left;
183                 else if (d < 0)
184                         p = &parent->rb_right;
185                 else {
186                         /* The attribute already exists; re-use it. */
187                         return attr;
188                 }
189         }
190         attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
191         if (!attr)
192                 return attr;
193         attr->state = GARP_APPLICANT_VO;
194         attr->type  = type;
195         attr->dlen  = len;
196         memcpy(attr->data, data, len);
197 
198         rb_link_node(&attr->node, parent, p);
199         rb_insert_color(&attr->node, &app->gid);
200         return attr;
201 }
202 
203 static void garp_attr_destroy(struct garp_applicant *app, struct garp_attr *attr)
204 {
205         rb_erase(&attr->node, &app->gid);
206         kfree(attr);
207 }
208 
209 static int garp_pdu_init(struct garp_applicant *app)
210 {
211         struct sk_buff *skb;
212         struct garp_pdu_hdr *gp;
213 
214 #define LLC_RESERVE     sizeof(struct llc_pdu_un)
215         skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
216                         GFP_ATOMIC);
217         if (!skb)
218                 return -ENOMEM;
219 
220         skb->dev = app->dev;
221         skb->protocol = htons(ETH_P_802_2);
222         skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
223 
224         gp = __skb_put(skb, sizeof(*gp));
225         put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
226 
227         app->pdu = skb;
228         return 0;
229 }
230 
231 static int garp_pdu_append_end_mark(struct garp_applicant *app)
232 {
233         if (skb_tailroom(app->pdu) < sizeof(u8))
234                 return -1;
235         __skb_put_u8(app->pdu, GARP_END_MARK);
236         return 0;
237 }
238 
239 static void garp_pdu_queue(struct garp_applicant *app)
240 {
241         if (!app->pdu)
242                 return;
243 
244         garp_pdu_append_end_mark(app);
245         garp_pdu_append_end_mark(app);
246 
247         llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
248                             LLC_SAP_BSPAN, LLC_PDU_CMD);
249         llc_pdu_init_as_ui_cmd(app->pdu);
250         llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
251                          app->app->proto.group_address);
252 
253         skb_queue_tail(&app->queue, app->pdu);
254         app->pdu = NULL;
255 }
256 
257 static void garp_queue_xmit(struct garp_applicant *app)
258 {
259         struct sk_buff *skb;
260 
261         while ((skb = skb_dequeue(&app->queue)))
262                 dev_queue_xmit(skb);
263 }
264 
265 static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
266 {
267         struct garp_msg_hdr *gm;
268 
269         if (skb_tailroom(app->pdu) < sizeof(*gm))
270                 return -1;
271         gm = __skb_put(app->pdu, sizeof(*gm));
272         gm->attrtype = attrtype;
273         garp_cb(app->pdu)->cur_type = attrtype;
274         return 0;
275 }
276 
277 static int garp_pdu_append_attr(struct garp_applicant *app,
278                                 const struct garp_attr *attr,
279                                 enum garp_attr_event event)
280 {
281         struct garp_attr_hdr *ga;
282         unsigned int len;
283         int err;
284 again:
285         if (!app->pdu) {
286                 err = garp_pdu_init(app);
287                 if (err < 0)
288                         return err;
289         }
290 
291         if (garp_cb(app->pdu)->cur_type != attr->type) {
292                 if (garp_cb(app->pdu)->cur_type &&
293                     garp_pdu_append_end_mark(app) < 0)
294                         goto queue;
295                 if (garp_pdu_append_msg(app, attr->type) < 0)
296                         goto queue;
297         }
298 
299         len = sizeof(*ga) + attr->dlen;
300         if (skb_tailroom(app->pdu) < len)
301                 goto queue;
302         ga = __skb_put(app->pdu, len);
303         ga->len   = len;
304         ga->event = event;
305         memcpy(ga->data, attr->data, attr->dlen);
306         return 0;
307 
308 queue:
309         garp_pdu_queue(app);
310         goto again;
311 }
312 
313 static void garp_attr_event(struct garp_applicant *app,
314                             struct garp_attr *attr, enum garp_event event)
315 {
316         enum garp_applicant_state state;
317 
318         state = garp_applicant_state_table[attr->state][event].state;
319         if (state == GARP_APPLICANT_INVALID)
320                 return;
321 
322         switch (garp_applicant_state_table[attr->state][event].action) {
323         case GARP_ACTION_NONE:
324                 break;
325         case GARP_ACTION_S_JOIN_IN:
326                 /* When appending the attribute fails, don't update state in
327                  * order to retry on next TRANSMIT_PDU event. */
328                 if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
329                         return;
330                 break;
331         case GARP_ACTION_S_LEAVE_EMPTY:
332                 garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
333                 /* As a pure applicant, sending a leave message implies that
334                  * the attribute was unregistered and can be destroyed. */
335                 garp_attr_destroy(app, attr);
336                 return;
337         default:
338                 WARN_ON(1);
339         }
340 
341         attr->state = state;
342 }
343 
344 int garp_request_join(const struct net_device *dev,
345                       const struct garp_application *appl,
346                       const void *data, u8 len, u8 type)
347 {
348         struct garp_port *port = rtnl_dereference(dev->garp_port);
349         struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
350         struct garp_attr *attr;
351 
352         spin_lock_bh(&app->lock);
353         attr = garp_attr_create(app, data, len, type);
354         if (!attr) {
355                 spin_unlock_bh(&app->lock);
356                 return -ENOMEM;
357         }
358         garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
359         spin_unlock_bh(&app->lock);
360         return 0;
361 }
362 EXPORT_SYMBOL_GPL(garp_request_join);
363 
364 void garp_request_leave(const struct net_device *dev,
365                         const struct garp_application *appl,
366                         const void *data, u8 len, u8 type)
367 {
368         struct garp_port *port = rtnl_dereference(dev->garp_port);
369         struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
370         struct garp_attr *attr;
371 
372         spin_lock_bh(&app->lock);
373         attr = garp_attr_lookup(app, data, len, type);
374         if (!attr) {
375                 spin_unlock_bh(&app->lock);
376                 return;
377         }
378         garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
379         spin_unlock_bh(&app->lock);
380 }
381 EXPORT_SYMBOL_GPL(garp_request_leave);
382 
383 static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
384 {
385         struct rb_node *node, *next;
386         struct garp_attr *attr;
387 
388         for (node = rb_first(&app->gid);
389              next = node ? rb_next(node) : NULL, node != NULL;
390              node = next) {
391                 attr = rb_entry(node, struct garp_attr, node);
392                 garp_attr_event(app, attr, event);
393         }
394 }
395 
396 static void garp_join_timer_arm(struct garp_applicant *app)
397 {
398         unsigned long delay;
399 
400         delay = (u64)msecs_to_jiffies(garp_join_time) * prandom_u32() >> 32;
401         mod_timer(&app->join_timer, jiffies + delay);
402 }
403 
404 static void garp_join_timer(struct timer_list *t)
405 {
406         struct garp_applicant *app = from_timer(app, t, join_timer);
407 
408         spin_lock(&app->lock);
409         garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
410         garp_pdu_queue(app);
411         spin_unlock(&app->lock);
412 
413         garp_queue_xmit(app);
414         garp_join_timer_arm(app);
415 }
416 
417 static int garp_pdu_parse_end_mark(struct sk_buff *skb)
418 {
419         if (!pskb_may_pull(skb, sizeof(u8)))
420                 return -1;
421         if (*skb->data == GARP_END_MARK) {
422                 skb_pull(skb, sizeof(u8));
423                 return -1;
424         }
425         return 0;
426 }
427 
428 static int garp_pdu_parse_attr(struct garp_applicant *app, struct sk_buff *skb,
429                                u8 attrtype)
430 {
431         const struct garp_attr_hdr *ga;
432         struct garp_attr *attr;
433         enum garp_event event;
434         unsigned int dlen;
435 
436         if (!pskb_may_pull(skb, sizeof(*ga)))
437                 return -1;
438         ga = (struct garp_attr_hdr *)skb->data;
439         if (ga->len < sizeof(*ga))
440                 return -1;
441 
442         if (!pskb_may_pull(skb, ga->len))
443                 return -1;
444         skb_pull(skb, ga->len);
445         dlen = sizeof(*ga) - ga->len;
446 
447         if (attrtype > app->app->maxattr)
448                 return 0;
449 
450         switch (ga->event) {
451         case GARP_LEAVE_ALL:
452                 if (dlen != 0)
453                         return -1;
454                 garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
455                 return 0;
456         case GARP_JOIN_EMPTY:
457                 event = GARP_EVENT_R_JOIN_EMPTY;
458                 break;
459         case GARP_JOIN_IN:
460                 event = GARP_EVENT_R_JOIN_IN;
461                 break;
462         case GARP_LEAVE_EMPTY:
463                 event = GARP_EVENT_R_LEAVE_EMPTY;
464                 break;
465         case GARP_EMPTY:
466                 event = GARP_EVENT_R_EMPTY;
467                 break;
468         default:
469                 return 0;
470         }
471 
472         if (dlen == 0)
473                 return -1;
474         attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
475         if (attr == NULL)
476                 return 0;
477         garp_attr_event(app, attr, event);
478         return 0;
479 }
480 
481 static int garp_pdu_parse_msg(struct garp_applicant *app, struct sk_buff *skb)
482 {
483         const struct garp_msg_hdr *gm;
484 
485         if (!pskb_may_pull(skb, sizeof(*gm)))
486                 return -1;
487         gm = (struct garp_msg_hdr *)skb->data;
488         if (gm->attrtype == 0)
489                 return -1;
490         skb_pull(skb, sizeof(*gm));
491 
492         while (skb->len > 0) {
493                 if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
494                         return -1;
495                 if (garp_pdu_parse_end_mark(skb) < 0)
496                         break;
497         }
498         return 0;
499 }
500 
501 static void garp_pdu_rcv(const struct stp_proto *proto, struct sk_buff *skb,
502                          struct net_device *dev)
503 {
504         struct garp_application *appl = proto->data;
505         struct garp_port *port;
506         struct garp_applicant *app;
507         const struct garp_pdu_hdr *gp;
508 
509         port = rcu_dereference(dev->garp_port);
510         if (!port)
511                 goto err;
512         app = rcu_dereference(port->applicants[appl->type]);
513         if (!app)
514                 goto err;
515 
516         if (!pskb_may_pull(skb, sizeof(*gp)))
517                 goto err;
518         gp = (struct garp_pdu_hdr *)skb->data;
519         if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
520                 goto err;
521         skb_pull(skb, sizeof(*gp));
522 
523         spin_lock(&app->lock);
524         while (skb->len > 0) {
525                 if (garp_pdu_parse_msg(app, skb) < 0)
526                         break;
527                 if (garp_pdu_parse_end_mark(skb) < 0)
528                         break;
529         }
530         spin_unlock(&app->lock);
531 err:
532         kfree_skb(skb);
533 }
534 
535 static int garp_init_port(struct net_device *dev)
536 {
537         struct garp_port *port;
538 
539         port = kzalloc(sizeof(*port), GFP_KERNEL);
540         if (!port)
541                 return -ENOMEM;
542         rcu_assign_pointer(dev->garp_port, port);
543         return 0;
544 }
545 
546 static void garp_release_port(struct net_device *dev)
547 {
548         struct garp_port *port = rtnl_dereference(dev->garp_port);
549         unsigned int i;
550 
551         for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
552                 if (rtnl_dereference(port->applicants[i]))
553                         return;
554         }
555         RCU_INIT_POINTER(dev->garp_port, NULL);
556         kfree_rcu(port, rcu);
557 }
558 
559 int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
560 {
561         struct garp_applicant *app;
562         int err;
563 
564         ASSERT_RTNL();
565 
566         if (!rtnl_dereference(dev->garp_port)) {
567                 err = garp_init_port(dev);
568                 if (err < 0)
569                         goto err1;
570         }
571 
572         err = -ENOMEM;
573         app = kzalloc(sizeof(*app), GFP_KERNEL);
574         if (!app)
575                 goto err2;
576 
577         err = dev_mc_add(dev, appl->proto.group_address);
578         if (err < 0)
579                 goto err3;
580 
581         app->dev = dev;
582         app->app = appl;
583         app->gid = RB_ROOT;
584         spin_lock_init(&app->lock);
585         skb_queue_head_init(&app->queue);
586         rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
587         timer_setup(&app->join_timer, garp_join_timer, 0);
588         garp_join_timer_arm(app);
589         return 0;
590 
591 err3:
592         kfree(app);
593 err2:
594         garp_release_port(dev);
595 err1:
596         return err;
597 }
598 EXPORT_SYMBOL_GPL(garp_init_applicant);
599 
600 void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
601 {
602         struct garp_port *port = rtnl_dereference(dev->garp_port);
603         struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
604 
605         ASSERT_RTNL();
606 
607         RCU_INIT_POINTER(port->applicants[appl->type], NULL);
608 
609         /* Delete timer and generate a final TRANSMIT_PDU event to flush out
610          * all pending messages before the applicant is gone. */
611         del_timer_sync(&app->join_timer);
612 
613         spin_lock_bh(&app->lock);
614         garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
615         garp_pdu_queue(app);
616         spin_unlock_bh(&app->lock);
617 
618         garp_queue_xmit(app);
619 
620         dev_mc_del(dev, appl->proto.group_address);
621         kfree_rcu(app, rcu);
622         garp_release_port(dev);
623 }
624 EXPORT_SYMBOL_GPL(garp_uninit_applicant);
625 
626 int garp_register_application(struct garp_application *appl)
627 {
628         appl->proto.rcv = garp_pdu_rcv;
629         appl->proto.data = appl;
630         return stp_proto_register(&appl->proto);
631 }
632 EXPORT_SYMBOL_GPL(garp_register_application);
633 
634 void garp_unregister_application(struct garp_application *appl)
635 {
636         stp_proto_unregister(&appl->proto);
637 }
638 EXPORT_SYMBOL_GPL(garp_unregister_application);
639 

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