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