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 = dev->garp_port;
 350         struct garp_applicant *app = 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 = dev->garp_port;
 370         struct garp_applicant *app = 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 = dev->garp_port;
 550         unsigned int i;
 551
 552         for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
 553                 if (port->applicants[i])
 554                         return;
 555         }
 556         rcu_assign_pointer(dev->garp_port, NULL);
 557         synchronize_rcu();
 558         kfree(port);
 559 }
 560
 561 int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
 562 {
 563         struct garp_applicant *app;
 564         int err;
 565
 566         ASSERT_RTNL();
 567
 568         if (!dev->garp_port) {
 569                 err = garp_init_port(dev);
 570                 if (err < 0)
 571                         goto err1;
 572         }
 573
 574         err = -ENOMEM;
 575         app = kzalloc(sizeof(*app), GFP_KERNEL);
 576         if (!app)
 577                 goto err2;
 578
 579         err = dev_mc_add(dev, appl->proto.group_address);
 580         if (err < 0)
 581                 goto err3;
 582
 583         app->dev = dev;
 584         app->app = appl;
 585         app->gid = RB_ROOT;
 586         spin_lock_init(&app->lock);
 587         skb_queue_head_init(&app->queue);
 588         rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
 589         setup_timer(&app->join_timer, garp_join_timer, (unsigned long)app);
 590         garp_join_timer_arm(app);
 591         return 0;
 592
 593 err3:
 594         kfree(app);
 595 err2:
 596         garp_release_port(dev);
 597 err1:
 598         return err;
 599 }
 600 EXPORT_SYMBOL_GPL(garp_init_applicant);
 601
 602 void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
 603 {
 604         struct garp_port *port = dev->garp_port;
 605         struct garp_applicant *app = port->applicants[appl->type];
 606
 607         ASSERT_RTNL();
 608
 609         rcu_assign_pointer(port->applicants[appl->type], NULL);
 610         synchronize_rcu();
 611
 612         /* Delete timer and generate a final TRANSMIT_PDU event to flush out
 613          * all pending messages before the applicant is gone. */
 614         del_timer_sync(&app->join_timer);
 615         garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
 616         garp_pdu_queue(app);
 617         garp_queue_xmit(app);
 618
 619         dev_mc_del(dev, appl->proto.group_address);
 620         kfree(app);
 621         garp_release_port(dev);
 622 }
 623 EXPORT_SYMBOL_GPL(garp_uninit_applicant);
 624
 625 int garp_register_application(struct garp_application *appl)
 626 {
 627         appl->proto.rcv = garp_pdu_rcv;
 628         appl->proto.data = appl;
 629         return stp_proto_register(&appl->proto);
 630 }
 631 EXPORT_SYMBOL_GPL(garp_register_application);
 632
 633 void garp_unregister_application(struct garp_application *appl)
 634 {
 635         stp_proto_unregister(&appl->proto);
 636 }
 637 EXPORT_SYMBOL_GPL(garp_unregister_application);