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
  24static unsigned int garp_join_time __read_mostly = 200;
  25module_param(garp_join_time, uint, 0644);
  26MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
  27MODULE_LICENSE("GPL");
  28
  29static 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
 140static 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
 150static 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
 170static 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
 203static 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
 209static 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
 231static 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
 239static 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
 257static 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
 265static 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
 277static 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;
 284again:
 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
 308queue:
 309        garp_pdu_queue(app);
 310        goto again;
 311}
 312
 313static 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
 344int 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}
 362EXPORT_SYMBOL_GPL(garp_request_join);
 363
 364void 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}
 381EXPORT_SYMBOL_GPL(garp_request_leave);
 382
 383static 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
 396static 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
 404static 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
 417static 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
 428static 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
 481static 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
 501static 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);
 531err:
 532        kfree_skb(skb);
 533}
 534
 535static 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
 546static 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
 559int 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        setup_timer(&app->join_timer, garp_join_timer, (unsigned long)app);
 588        garp_join_timer_arm(app);
 589        return 0;
 590
 591err3:
 592        kfree(app);
 593err2:
 594        garp_release_port(dev);
 595err1:
 596        return err;
 597}
 598EXPORT_SYMBOL_GPL(garp_init_applicant);
 599
 600void 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        garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
 613        garp_pdu_queue(app);
 614        garp_queue_xmit(app);
 615
 616        dev_mc_del(dev, appl->proto.group_address);
 617        kfree_rcu(app, rcu);
 618        garp_release_port(dev);
 619}
 620EXPORT_SYMBOL_GPL(garp_uninit_applicant);
 621
 622int garp_register_application(struct garp_application *appl)
 623{
 624        appl->proto.rcv = garp_pdu_rcv;
 625        appl->proto.data = appl;
 626        return stp_proto_register(&appl->proto);
 627}
 628EXPORT_SYMBOL_GPL(garp_register_application);
 629
 630void garp_unregister_application(struct garp_application *appl)
 631{
 632        stp_proto_unregister(&appl->proto);
 633}
 634EXPORT_SYMBOL_GPL(garp_unregister_application);
 635
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