net/bridge/br_mdb.c

   1 #include <linux/err.h>
   2 #include <linux/igmp.h>
   3 #include <linux/kernel.h>
   4 #include <linux/netdevice.h>
   5 #include <linux/rculist.h>
   6 #include <linux/skbuff.h>
   7 #include <linux/if_ether.h>
   8 #include <net/ip.h>
   9 #include <net/netlink.h>
  10 #if IS_ENABLED(CONFIG_IPV6)
  11 #include <net/ipv6.h>
  12 #endif
  13
  14 #include "br_private.h"
  15
  16 static int br_rports_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
  17                                struct net_device *dev)
  18 {
  19         struct net_bridge *br = netdev_priv(dev);
  20         struct net_bridge_port *p;
  21         struct hlist_node *n;
  22         struct nlattr *nest;
  23
  24         if (!br->multicast_router || hlist_empty(&br->router_list))
  25                 return 0;
  26
  27         nest = nla_nest_start(skb, MDBA_ROUTER);
  28         if (nest == NULL)
  29                 return -EMSGSIZE;
  30
  31         hlist_for_each_entry_rcu(p, n, &br->router_list, rlist) {
  32                 if (p && nla_put_u32(skb, MDBA_ROUTER_PORT, p->dev->ifindex))
  33                         goto fail;
  34         }
  35
  36         nla_nest_end(skb, nest);
  37         return 0;
  38 fail:
  39         nla_nest_cancel(skb, nest);
  40         return -EMSGSIZE;
  41 }
  42
  43 static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
  44                             struct net_device *dev)
  45 {
  46         struct net_bridge *br = netdev_priv(dev);
  47         struct net_bridge_mdb_htable *mdb;
  48         struct nlattr *nest, *nest2;
  49         int i, err = 0;
  50         int idx = 0, s_idx = cb->args[1];
  51
  52         if (br->multicast_disabled)
  53                 return 0;
  54
  55         mdb = rcu_dereference(br->mdb);
  56         if (!mdb)
  57                 return 0;
  58
  59         nest = nla_nest_start(skb, MDBA_MDB);
  60         if (nest == NULL)
  61                 return -EMSGSIZE;
  62
  63         for (i = 0; i < mdb->max; i++) {
  64                 struct hlist_node *h;
  65                 struct net_bridge_mdb_entry *mp;
  66                 struct net_bridge_port_group *p, **pp;
  67                 struct net_bridge_port *port;
  68
  69                 hlist_for_each_entry_rcu(mp, h, &mdb->mhash[i], hlist[mdb->ver]) {
  70                         if (idx < s_idx)
  71                                 goto skip;
  72
  73                         nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
  74                         if (nest2 == NULL) {
  75                                 err = -EMSGSIZE;
  76                                 goto out;
  77                         }
  78
  79                         for (pp = &mp->ports;
  80                              (p = rcu_dereference(*pp)) != NULL;
  81                               pp = &p->next) {
  82                                 port = p->port;
  83                                 if (port) {
  84                                         struct br_mdb_entry e;
  85                                         e.ifindex = port->dev->ifindex;
  86                                         e.state = p->state;
  87                                         if (p->addr.proto == htons(ETH_P_IP))
  88                                                 e.addr.u.ip4 = p->addr.u.ip4;
  89 #if IS_ENABLED(CONFIG_IPV6)
  90                                         if (p->addr.proto == htons(ETH_P_IPV6))
  91                                                 e.addr.u.ip6 = p->addr.u.ip6;
  92 #endif
  93                                         e.addr.proto = p->addr.proto;
  94                                         if (nla_put(skb, MDBA_MDB_ENTRY_INFO, sizeof(e), &e)) {
  95                                                 nla_nest_cancel(skb, nest2);
  96                                                 err = -EMSGSIZE;
  97                                                 goto out;
  98                                         }
  99                                 }
 100                         }
 101                         nla_nest_end(skb, nest2);
 102                 skip:
 103                         idx++;
 104                 }
 105         }
 106
 107 out:
 108         cb->args[1] = idx;
 109         nla_nest_end(skb, nest);
 110         return err;
 111 }
 112
 113 static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 114 {
 115         struct net_device *dev;
 116         struct net *net = sock_net(skb->sk);
 117         struct nlmsghdr *nlh = NULL;
 118         int idx = 0, s_idx;
 119
 120         s_idx = cb->args[0];
 121
 122         rcu_read_lock();
 123
 124         /* In theory this could be wrapped to 0... */
 125         cb->seq = net->dev_base_seq + br_mdb_rehash_seq;
 126
 127         for_each_netdev_rcu(net, dev) {
 128                 if (dev->priv_flags & IFF_EBRIDGE) {
 129                         struct br_port_msg *bpm;
 130
 131                         if (idx < s_idx)
 132                                 goto skip;
 133
 134                         nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
 135                                         cb->nlh->nlmsg_seq, RTM_GETMDB,
 136                                         sizeof(*bpm), NLM_F_MULTI);
 137                         if (nlh == NULL)
 138                                 break;
 139
 140                         bpm = nlmsg_data(nlh);
 141                         bpm->ifindex = dev->ifindex;
 142                         if (br_mdb_fill_info(skb, cb, dev) < 0)
 143                                 goto out;
 144                         if (br_rports_fill_info(skb, cb, dev) < 0)
 145                                 goto out;
 146
 147                         cb->args[1] = 0;
 148                         nlmsg_end(skb, nlh);
 149                 skip:
 150                         idx++;
 151                 }
 152         }
 153
 154 out:
 155         if (nlh)
 156                 nlmsg_end(skb, nlh);
 157         rcu_read_unlock();
 158         cb->args[0] = idx;
 159         return skb->len;
 160 }
 161
 162 static int nlmsg_populate_mdb_fill(struct sk_buff *skb,
 163                                    struct net_device *dev,
 164                                    struct br_mdb_entry *entry, u32 pid,
 165                                    u32 seq, int type, unsigned int flags)
 166 {
 167         struct nlmsghdr *nlh;
 168         struct br_port_msg *bpm;
 169         struct nlattr *nest, *nest2;
 170
 171         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*bpm), NLM_F_MULTI);
 172         if (!nlh)
 173                 return -EMSGSIZE;
 174
 175         bpm = nlmsg_data(nlh);
 176         bpm->family  = AF_BRIDGE;
 177         bpm->ifindex = dev->ifindex;
 178         nest = nla_nest_start(skb, MDBA_MDB);
 179         if (nest == NULL)
 180                 goto cancel;
 181         nest2 = nla_nest_start(skb, MDBA_MDB_ENTRY);
 182         if (nest2 == NULL)
 183                 goto end;
 184
 185         if (nla_put(skb, MDBA_MDB_ENTRY_INFO, sizeof(*entry), entry))
 186                 goto end;
 187
 188         nla_nest_end(skb, nest2);
 189         nla_nest_end(skb, nest);
 190         return nlmsg_end(skb, nlh);
 191
 192 end:
 193         nla_nest_end(skb, nest);
 194 cancel:
 195         nlmsg_cancel(skb, nlh);
 196         return -EMSGSIZE;
 197 }
 198
 199 static inline size_t rtnl_mdb_nlmsg_size(void)
 200 {
 201         return NLMSG_ALIGN(sizeof(struct br_port_msg))
 202                 + nla_total_size(sizeof(struct br_mdb_entry));
 203 }
 204
 205 static void __br_mdb_notify(struct net_device *dev, struct br_mdb_entry *entry,
 206                             int type)
 207 {
 208         struct net *net = dev_net(dev);
 209         struct sk_buff *skb;
 210         int err = -ENOBUFS;
 211
 212         skb = nlmsg_new(rtnl_mdb_nlmsg_size(), GFP_ATOMIC);
 213         if (!skb)
 214                 goto errout;
 215
 216         err = nlmsg_populate_mdb_fill(skb, dev, entry, 0, 0, type, NTF_SELF);
 217         if (err < 0) {
 218                 kfree_skb(skb);
 219                 goto errout;
 220         }
 221
 222         rtnl_notify(skb, net, 0, RTNLGRP_MDB, NULL, GFP_ATOMIC);
 223         return;
 224 errout:
 225         rtnl_set_sk_err(net, RTNLGRP_MDB, err);
 226 }
 227
 228 void br_mdb_notify(struct net_device *dev, struct net_bridge_port *port,
 229                    struct br_ip *group, int type)
 230 {
 231         struct br_mdb_entry entry;
 232
 233         entry.ifindex = port->dev->ifindex;
 234         entry.addr.proto = group->proto;
 235         entry.addr.u.ip4 = group->u.ip4;
 236 #if IS_ENABLED(CONFIG_IPV6)
 237         entry.addr.u.ip6 = group->u.ip6;
 238 #endif
 239         __br_mdb_notify(dev, &entry, type);
 240 }
 241
 242 static bool is_valid_mdb_entry(struct br_mdb_entry *entry)
 243 {
 244         if (entry->ifindex == 0)
 245                 return false;
 246
 247         if (entry->addr.proto == htons(ETH_P_IP)) {
 248                 if (!ipv4_is_multicast(entry->addr.u.ip4))
 249                         return false;
 250                 if (ipv4_is_local_multicast(entry->addr.u.ip4))
 251                         return false;
 252 #if IS_ENABLED(CONFIG_IPV6)
 253         } else if (entry->addr.proto == htons(ETH_P_IPV6)) {
 254                 if (!ipv6_is_transient_multicast(&entry->addr.u.ip6))
 255                         return false;
 256 #endif
 257         } else
 258                 return false;
 259         if (entry->state != MDB_PERMANENT && entry->state != MDB_TEMPORARY)
 260                 return false;
 261
 262         return true;
 263 }
 264
 265 static int br_mdb_parse(struct sk_buff *skb, struct nlmsghdr *nlh,
 266                         struct net_device **pdev, struct br_mdb_entry **pentry)
 267 {
 268         struct net *net = sock_net(skb->sk);
 269         struct br_mdb_entry *entry;
 270         struct br_port_msg *bpm;
 271         struct nlattr *tb[MDBA_SET_ENTRY_MAX+1];
 272         struct net_device *dev;
 273         int err;
 274
 275         if (!capable(CAP_NET_ADMIN))
 276                 return -EPERM;
 277
 278         err = nlmsg_parse(nlh, sizeof(*bpm), tb, MDBA_SET_ENTRY, NULL);
 279         if (err < 0)
 280                 return err;
 281
 282         bpm = nlmsg_data(nlh);
 283         if (bpm->ifindex == 0) {
 284                 pr_info("PF_BRIDGE: br_mdb_parse() with invalid ifindex\n");
 285                 return -EINVAL;
 286         }
 287
 288         dev = __dev_get_by_index(net, bpm->ifindex);
 289         if (dev == NULL) {
 290                 pr_info("PF_BRIDGE: br_mdb_parse() with unknown ifindex\n");
 291                 return -ENODEV;
 292         }
 293
 294         if (!(dev->priv_flags & IFF_EBRIDGE)) {
 295                 pr_info("PF_BRIDGE: br_mdb_parse() with non-bridge\n");
 296                 return -EOPNOTSUPP;
 297         }
 298
 299         *pdev = dev;
 300
 301         if (!tb[MDBA_SET_ENTRY] ||
 302             nla_len(tb[MDBA_SET_ENTRY]) != sizeof(struct br_mdb_entry)) {
 303                 pr_info("PF_BRIDGE: br_mdb_parse() with invalid attr\n");
 304                 return -EINVAL;
 305         }
 306
 307         entry = nla_data(tb[MDBA_SET_ENTRY]);
 308         if (!is_valid_mdb_entry(entry)) {
 309                 pr_info("PF_BRIDGE: br_mdb_parse() with invalid entry\n");
 310                 return -EINVAL;
 311         }
 312
 313         *pentry = entry;
 314         return 0;
 315 }
 316
 317 static int br_mdb_add_group(struct net_bridge *br, struct net_bridge_port *port,
 318                             struct br_ip *group, unsigned char state)
 319 {
 320         struct net_bridge_mdb_entry *mp;
 321         struct net_bridge_port_group *p;
 322         struct net_bridge_port_group __rcu **pp;
 323         struct net_bridge_mdb_htable *mdb;
 324         int err;
 325
 326         mdb = mlock_dereference(br->mdb, br);
 327         mp = br_mdb_ip_get(mdb, group);
 328         if (!mp) {
 329                 mp = br_multicast_new_group(br, port, group);
 330                 err = PTR_ERR(mp);
 331                 if (IS_ERR(mp))
 332                         return err;
 333         }
 334
 335         for (pp = &mp->ports;
 336              (p = mlock_dereference(*pp, br)) != NULL;
 337              pp = &p->next) {
 338                 if (p->port == port)
 339                         return -EEXIST;
 340                 if ((unsigned long)p->port < (unsigned long)port)
 341                         break;
 342         }
 343
 344         p = br_multicast_new_port_group(port, group, *pp, state);
 345         if (unlikely(!p))
 346                 return -ENOMEM;
 347         rcu_assign_pointer(*pp, p);
 348
 349         br_mdb_notify(br->dev, port, group, RTM_NEWMDB);
 350         return 0;
 351 }
 352
 353 static int __br_mdb_add(struct net *net, struct net_bridge *br,
 354                         struct br_mdb_entry *entry)
 355 {
 356         struct br_ip ip;
 357         struct net_device *dev;
 358         struct net_bridge_port *p;
 359         int ret;
 360
 361         if (!netif_running(br->dev) || br->multicast_disabled)
 362                 return -EINVAL;
 363
 364         dev = __dev_get_by_index(net, entry->ifindex);
 365         if (!dev)
 366                 return -ENODEV;
 367
 368         p = br_port_get_rtnl(dev);
 369         if (!p || p->br != br || p->state == BR_STATE_DISABLED)
 370                 return -EINVAL;
 371
 372         ip.proto = entry->addr.proto;
 373         if (ip.proto == htons(ETH_P_IP))
 374                 ip.u.ip4 = entry->addr.u.ip4;
 375 #if IS_ENABLED(CONFIG_IPV6)
 376         else
 377                 ip.u.ip6 = entry->addr.u.ip6;
 378 #endif
 379
 380         spin_lock_bh(&br->multicast_lock);
 381         ret = br_mdb_add_group(br, p, &ip, entry->state);
 382         spin_unlock_bh(&br->multicast_lock);
 383         return ret;
 384 }
 385
 386 static int br_mdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 387 {
 388         struct net *net = sock_net(skb->sk);
 389         struct br_mdb_entry *entry;
 390         struct net_device *dev;
 391         struct net_bridge *br;
 392         int err;
 393
 394         err = br_mdb_parse(skb, nlh, &dev, &entry);
 395         if (err < 0)
 396                 return err;
 397
 398         br = netdev_priv(dev);
 399
 400         err = __br_mdb_add(net, br, entry);
 401         if (!err)
 402                 __br_mdb_notify(dev, entry, RTM_NEWMDB);
 403         return err;
 404 }
 405
 406 static int __br_mdb_del(struct net_bridge *br, struct br_mdb_entry *entry)
 407 {
 408         struct net_bridge_mdb_htable *mdb;
 409         struct net_bridge_mdb_entry *mp;
 410         struct net_bridge_port_group *p;
 411         struct net_bridge_port_group __rcu **pp;
 412         struct br_ip ip;
 413         int err = -EINVAL;
 414
 415         if (!netif_running(br->dev) || br->multicast_disabled)
 416                 return -EINVAL;
 417
 418         if (timer_pending(&br->multicast_querier_timer))
 419                 return -EBUSY;
 420
 421         ip.proto = entry->addr.proto;
 422         if (ip.proto == htons(ETH_P_IP))
 423                 ip.u.ip4 = entry->addr.u.ip4;
 424 #if IS_ENABLED(CONFIG_IPV6)
 425         else
 426                 ip.u.ip6 = entry->addr.u.ip6;
 427 #endif
 428
 429         spin_lock_bh(&br->multicast_lock);
 430         mdb = mlock_dereference(br->mdb, br);
 431
 432         mp = br_mdb_ip_get(mdb, &ip);
 433         if (!mp)
 434                 goto unlock;
 435
 436         for (pp = &mp->ports;
 437              (p = mlock_dereference(*pp, br)) != NULL;
 438              pp = &p->next) {
 439                 if (!p->port || p->port->dev->ifindex != entry->ifindex)
 440                         continue;
 441
 442                 if (p->port->state == BR_STATE_DISABLED)
 443                         goto unlock;
 444
 445                 rcu_assign_pointer(*pp, p->next);
 446                 hlist_del_init(&p->mglist);
 447                 del_timer(&p->timer);
 448                 call_rcu_bh(&p->rcu, br_multicast_free_pg);
 449                 err = 0;
 450
 451                 if (!mp->ports && !mp->mglist &&
 452                     netif_running(br->dev))
 453                         mod_timer(&mp->timer, jiffies);
 454                 break;
 455         }
 456
 457 unlock:
 458         spin_unlock_bh(&br->multicast_lock);
 459         return err;
 460 }
 461
 462 static int br_mdb_del(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 463 {
 464         struct net_device *dev;
 465         struct br_mdb_entry *entry;
 466         struct net_bridge *br;
 467         int err;
 468
 469         err = br_mdb_parse(skb, nlh, &dev, &entry);
 470         if (err < 0)
 471                 return err;
 472
 473         br = netdev_priv(dev);
 474
 475         err = __br_mdb_del(br, entry);
 476         if (!err)
 477                 __br_mdb_notify(dev, entry, RTM_DELMDB);
 478         return err;
 479 }
 480
 481 void br_mdb_init(void)
 482 {
 483         rtnl_register(PF_BRIDGE, RTM_GETMDB, NULL, br_mdb_dump, NULL);
 484         rtnl_register(PF_BRIDGE, RTM_NEWMDB, br_mdb_add, NULL, NULL);
 485         rtnl_register(PF_BRIDGE, RTM_DELMDB, br_mdb_del, NULL, NULL);
 486 }
 487
 488 void br_mdb_uninit(void)
 489 {
 490         rtnl_unregister(PF_BRIDGE, RTM_GETMDB);
 491         rtnl_unregister(PF_BRIDGE, RTM_NEWMDB);
 492         rtnl_unregister(PF_BRIDGE, RTM_DELMDB);
 493 }