net: convert multicast list to list_head
[linux-2.6.git] / net / 802 / garp.c
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 <net/llc.h>
18 #include <net/llc_pdu.h>
19 #include <net/garp.h>
20 #include <asm/unaligned.h>
21
22 static unsigned int garp_join_time __read_mostly = 200;
23 module_param(garp_join_time, uint, 0644);
24 MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
25 MODULE_LICENSE("GPL");
26
27 static const struct garp_state_trans {
28         u8      state;
29         u8      action;
30 } garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = {
31         [GARP_APPLICANT_VA] = {
32                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_AA,
33                                                     .action = GARP_ACTION_S_JOIN_IN },
34                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AA },
35                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
36                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
37                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VA },
38                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
39                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
40                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
41         },
42         [GARP_APPLICANT_AA] = {
43                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_QA,
44                                                     .action = GARP_ACTION_S_JOIN_IN },
45                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QA },
46                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
47                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
48                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VA },
49                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
50                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
51                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
52         },
53         [GARP_APPLICANT_QA] = {
54                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
55                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QA },
56                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VA },
57                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VA },
58                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
59                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
60                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
61                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_LA },
62         },
63         [GARP_APPLICANT_LA] = {
64                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_VO,
65                                                     .action = GARP_ACTION_S_LEAVE_EMPTY },
66                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_LA },
67                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
68                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_LA },
69                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_LA },
70                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
71                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_VA },
72                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
73         },
74         [GARP_APPLICANT_VP] = {
75                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_AA,
76                                                     .action = GARP_ACTION_S_JOIN_IN },
77                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AP },
78                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
79                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
80                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
81                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
82                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
83                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_VO },
84         },
85         [GARP_APPLICANT_AP] = {
86                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_QA,
87                                                     .action = GARP_ACTION_S_JOIN_IN },
88                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QP },
89                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
90                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
91                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
92                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
93                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
94                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_AO },
95         },
96         [GARP_APPLICANT_QP] = {
97                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
98                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QP },
99                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VP },
100                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VP },
101                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VP },
102                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VP },
103                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_INVALID },
104                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_QO },
105         },
106         [GARP_APPLICANT_VO] = {
107                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
108                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_AO },
109                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
110                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
111                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
112                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
113                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_VP },
114                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
115         },
116         [GARP_APPLICANT_AO] = {
117                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
118                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QO },
119                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
120                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
121                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
122                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
123                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_AP },
124                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
125         },
126         [GARP_APPLICANT_QO] = {
127                 [GARP_EVENT_TRANSMIT_PDU]       = { .state = GARP_APPLICANT_INVALID },
128                 [GARP_EVENT_R_JOIN_IN]          = { .state = GARP_APPLICANT_QO },
129                 [GARP_EVENT_R_JOIN_EMPTY]       = { .state = GARP_APPLICANT_VO },
130                 [GARP_EVENT_R_EMPTY]            = { .state = GARP_APPLICANT_VO },
131                 [GARP_EVENT_R_LEAVE_IN]         = { .state = GARP_APPLICANT_VO },
132                 [GARP_EVENT_R_LEAVE_EMPTY]      = { .state = GARP_APPLICANT_VO },
133                 [GARP_EVENT_REQ_JOIN]           = { .state = GARP_APPLICANT_QP },
134                 [GARP_EVENT_REQ_LEAVE]          = { .state = GARP_APPLICANT_INVALID },
135         },
136 };
137
138 static int garp_attr_cmp(const struct garp_attr *attr,
139                          const void *data, u8 len, u8 type)
140 {
141         if (attr->type != type)
142                 return attr->type - type;
143         if (attr->dlen != len)
144                 return attr->dlen - len;
145         return memcmp(attr->data, data, len);
146 }
147
148 static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app,
149                                           const void *data, u8 len, u8 type)
150 {
151         struct rb_node *parent = app->gid.rb_node;
152         struct garp_attr *attr;
153         int d;
154
155         while (parent) {
156                 attr = rb_entry(parent, struct garp_attr, node);
157                 d = garp_attr_cmp(attr, data, len, type);
158                 if (d < 0)
159                         parent = parent->rb_left;
160                 else if (d > 0)
161                         parent = parent->rb_right;
162                 else
163                         return attr;
164         }
165         return NULL;
166 }
167
168 static void garp_attr_insert(struct garp_applicant *app, struct garp_attr *new)
169 {
170         struct rb_node *parent = NULL, **p = &app->gid.rb_node;
171         struct garp_attr *attr;
172         int d;
173
174         while (*p) {
175                 parent = *p;
176                 attr = rb_entry(parent, struct garp_attr, node);
177                 d = garp_attr_cmp(attr, new->data, new->dlen, new->type);
178                 if (d < 0)
179                         p = &parent->rb_left;
180                 else if (d > 0)
181                         p = &parent->rb_right;
182         }
183         rb_link_node(&new->node, parent, p);
184         rb_insert_color(&new->node, &app->gid);
185 }
186
187 static struct garp_attr *garp_attr_create(struct garp_applicant *app,
188                                           const void *data, u8 len, u8 type)
189 {
190         struct garp_attr *attr;
191
192         attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
193         if (!attr)
194                 return attr;
195         attr->state = GARP_APPLICANT_VO;
196         attr->type  = type;
197         attr->dlen  = len;
198         memcpy(attr->data, data, len);
199         garp_attr_insert(app, attr);
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 = (struct garp_pdu_hdr *)__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         *(u8 *)__skb_put(app->pdu, sizeof(u8)) = 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 = (struct garp_msg_hdr *)__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 = (struct garp_attr_hdr *)__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 = dev->garp_port;
349         struct garp_applicant *app = 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 = dev->garp_port;
369         struct garp_applicant *app = 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) * net_random() >> 32;
401         mod_timer(&app->join_timer, jiffies + delay);
402 }
403
404 static void garp_join_timer(unsigned long data)
405 {
406         struct garp_applicant *app = (struct garp_applicant *)data;
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 = dev->garp_port;
549         unsigned int i;
550
551         for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
552                 if (port->applicants[i])
553                         return;
554         }
555         rcu_assign_pointer(dev->garp_port, NULL);
556         synchronize_rcu();
557         kfree(port);
558 }
559
560 int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
561 {
562         struct garp_applicant *app;
563         int err;
564
565         ASSERT_RTNL();
566
567         if (!dev->garp_port) {
568                 err = garp_init_port(dev);
569                 if (err < 0)
570                         goto err1;
571         }
572
573         err = -ENOMEM;
574         app = kzalloc(sizeof(*app), GFP_KERNEL);
575         if (!app)
576                 goto err2;
577
578         err = dev_mc_add(dev, appl->proto.group_address);
579         if (err < 0)
580                 goto err3;
581
582         app->dev = dev;
583         app->app = appl;
584         app->gid = RB_ROOT;
585         spin_lock_init(&app->lock);
586         skb_queue_head_init(&app->queue);
587         rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
588         setup_timer(&app->join_timer, garp_join_timer, (unsigned long)app);
589         garp_join_timer_arm(app);
590         return 0;
591
592 err3:
593         kfree(app);
594 err2:
595         garp_release_port(dev);
596 err1:
597         return err;
598 }
599 EXPORT_SYMBOL_GPL(garp_init_applicant);
600
601 void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
602 {
603         struct garp_port *port = dev->garp_port;
604         struct garp_applicant *app = port->applicants[appl->type];
605
606         ASSERT_RTNL();
607
608         rcu_assign_pointer(port->applicants[appl->type], NULL);
609         synchronize_rcu();
610
611         /* Delete timer and generate a final TRANSMIT_PDU event to flush out
612          * all pending messages before the applicant is gone. */
613         del_timer_sync(&app->join_timer);
614         garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
615         garp_pdu_queue(app);
616         garp_queue_xmit(app);
617
618         dev_mc_del(dev, appl->proto.group_address);
619         kfree(app);
620         garp_release_port(dev);
621 }
622 EXPORT_SYMBOL_GPL(garp_uninit_applicant);
623
624 int garp_register_application(struct garp_application *appl)
625 {
626         appl->proto.rcv = garp_pdu_rcv;
627         appl->proto.data = appl;
628         return stp_proto_register(&appl->proto);
629 }
630 EXPORT_SYMBOL_GPL(garp_register_application);
631
632 void garp_unregister_application(struct garp_application *appl)
633 {
634         stp_proto_unregister(&appl->proto);
635 }
636 EXPORT_SYMBOL_GPL(garp_unregister_application);