datapath/brcompat.c

   1 /*
   2  * Copyright (c) 2009 Nicira Networks.
   3  * Distributed under the terms of the GNU GPL version 2.
   4  *
   5  * Significant portions of this file may be copied from parts of the Linux
   6  * kernel, by Linus Torvalds and others.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <asm/uaccess.h>
  11 #include <linux/completion.h>
  12 #include <linux/delay.h>
  13 #include <linux/etherdevice.h>
  14 #include <linux/if_bridge.h>
  15 #include <linux/rculist.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/rtnetlink.h>
  18 #include <net/genetlink.h>
  19
  20 #include "compat.h"
  21 #include "openvswitch/brcompat-netlink.h"
  22 #include "brc_procfs.h"
  23 #include "brc_sysfs.h"
  24 #include "datapath.h"
  25 #include "dp_dev.h"
  26
  27 static struct genl_family brc_genl_family;
  28 static struct genl_multicast_group brc_mc_group;
  29
  30 /* Time to wait for ovs-vswitchd to respond to a datapath action, in
  31  * jiffies. */
  32 #define BRC_TIMEOUT (HZ * 5)
  33
  34 /* Mutex to serialize ovs-brcompatd callbacks.  (Some callbacks naturally hold
  35  * br_ioctl_mutex, others hold rtnl_lock, but we can't take the former
  36  * ourselves and we don't want to hold the latter over a potentially long
  37  * period of time.) */
  38 static DEFINE_MUTEX(brc_serial);
  39
  40 /* Userspace communication. */
  41 static DEFINE_SPINLOCK(brc_lock);    /* Ensure atomic access to these vars. */
  42 static DECLARE_COMPLETION(brc_done); /* Userspace signaled operation done? */
  43 static struct sk_buff *brc_reply;    /* Reply from userspace. */
  44 static u32 brc_seq;                  /* Sequence number for current op. */
  45
  46 static struct sk_buff *brc_send_command(struct sk_buff *, struct nlattr **attrs);
  47 static int brc_send_simple_command(struct sk_buff *);
  48
  49 static int
  50 get_dp_ifindices(int *indices, int num)
  51 {
  52         int i, index = 0;
  53
  54         rcu_read_lock();
  55         for (i=0; i < ODP_MAX && index < num; i++) {
  56                 struct datapath *dp = get_dp(i);
  57                 if (!dp)
  58                         continue;
  59                 indices[index++] = dp->ports[ODPP_LOCAL]->dev->ifindex;
  60         }
  61         rcu_read_unlock();
  62
  63         return index;
  64 }
  65
  66 static void
  67 get_port_ifindices(struct datapath *dp, int *ifindices, int num)
  68 {
  69         struct net_bridge_port *p;
  70
  71         rcu_read_lock();
  72         list_for_each_entry_rcu (p, &dp->port_list, node) {
  73                 if (p->port_no < num)
  74                         ifindices[p->port_no] = p->dev->ifindex;
  75         }
  76         rcu_read_unlock();
  77 }
  78
  79 static struct sk_buff *
  80 brc_make_request(int op, const char *bridge, const char *port)
  81 {
  82         struct sk_buff *skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
  83         if (!skb)
  84                 goto error;
  85
  86         genlmsg_put(skb, 0, 0, &brc_genl_family, 0, op);
  87         NLA_PUT_STRING(skb, BRC_GENL_A_DP_NAME, bridge);
  88         if (port)
  89                 NLA_PUT_STRING(skb, BRC_GENL_A_PORT_NAME, port);
  90         return skb;
  91
  92 nla_put_failure:
  93         kfree_skb(skb);
  94 error:
  95         return NULL;
  96 }
  97
  98 static int brc_send_simple_command(struct sk_buff *request)
  99 {
 100         struct nlattr *attrs[BRC_GENL_A_MAX + 1];
 101         struct sk_buff *reply;
 102         int error;
 103
 104         reply = brc_send_command(request, attrs);
 105         if (IS_ERR(reply))
 106                 return PTR_ERR(reply);
 107
 108         error = nla_get_u32(attrs[BRC_GENL_A_ERR_CODE]);
 109         kfree_skb(reply);
 110         return -error;
 111 }
 112
 113 static int brc_add_del_bridge(char __user *uname, int add)
 114 {
 115         struct sk_buff *request;
 116         char name[IFNAMSIZ];
 117
 118         if (copy_from_user(name, uname, IFNAMSIZ))
 119                 return -EFAULT;
 120
 121         name[IFNAMSIZ - 1] = 0;
 122         request = brc_make_request(add ? BRC_GENL_C_DP_ADD : BRC_GENL_C_DP_DEL,
 123                                    name, NULL);
 124         if (!request)
 125                 return -ENOMEM;
 126
 127         return brc_send_simple_command(request);
 128 }
 129
 130 static int brc_get_bridges(int __user *uindices, int n)
 131 {
 132         int *indices;
 133         int ret;
 134
 135         if (n >= 2048)
 136                 return -ENOMEM;
 137
 138         indices = kcalloc(n, sizeof(int), GFP_KERNEL);
 139         if (indices == NULL)
 140                 return -ENOMEM;
 141
 142         n = get_dp_ifindices(indices, n);
 143
 144         ret = copy_to_user(uindices, indices, n * sizeof(int)) ? -EFAULT : n;
 145
 146         kfree(indices);
 147         return ret;
 148 }
 149
 150 /* Legacy deviceless bridge ioctl's.  Called with br_ioctl_mutex. */
 151 static int
 152 old_deviceless(void __user *uarg)
 153 {
 154         unsigned long args[3];
 155
 156         if (copy_from_user(args, uarg, sizeof(args)))
 157                 return -EFAULT;
 158
 159         switch (args[0]) {
 160         case BRCTL_GET_BRIDGES:
 161                 return brc_get_bridges((int __user *)args[1], args[2]);
 162
 163         case BRCTL_ADD_BRIDGE:
 164                 return brc_add_del_bridge((void __user *)args[1], 1);
 165         case BRCTL_DEL_BRIDGE:
 166                 return brc_add_del_bridge((void __user *)args[1], 0);
 167         }
 168
 169         return -EOPNOTSUPP;
 170 }
 171
 172 /* Called with the br_ioctl_mutex. */
 173 static int
 174 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 175 brc_ioctl_deviceless_stub(unsigned int cmd, void __user *uarg)
 176 #else
 177 brc_ioctl_deviceless_stub(struct net *net, unsigned int cmd, void __user *uarg)
 178 #endif
 179 {
 180         switch (cmd) {
 181         case SIOCGIFBR:
 182         case SIOCSIFBR:
 183                 return old_deviceless(uarg);
 184
 185         case SIOCBRADDBR:
 186                 return brc_add_del_bridge(uarg, 1);
 187         case SIOCBRDELBR:
 188                 return brc_add_del_bridge(uarg, 0);
 189         }
 190
 191         return -EOPNOTSUPP;
 192 }
 193
 194 static int
 195 brc_add_del_port(struct net_device *dev, int port_ifindex, int add)
 196 {
 197         struct sk_buff *request;
 198         struct net_device *port;
 199         int err;
 200
 201         port = __dev_get_by_index(&init_net, port_ifindex);
 202         if (!port)
 203                 return -EINVAL;
 204
 205         /* Save name of dev and port because there's a race between the
 206          * rtnl_unlock() and the brc_send_simple_command(). */
 207         request = brc_make_request(add ? BRC_GENL_C_PORT_ADD : BRC_GENL_C_PORT_DEL,
 208                                    dev->name, port->name);
 209         if (!request)
 210                 return -ENOMEM;
 211
 212         rtnl_unlock();
 213         err = brc_send_simple_command(request);
 214         rtnl_lock();
 215
 216         return err;
 217 }
 218
 219 static int
 220 brc_get_bridge_info(struct net_device *dev, struct __bridge_info __user *ub)
 221 {
 222         struct __bridge_info b;
 223         u64 id = 0;
 224         int i;
 225
 226         memset(&b, 0, sizeof(struct __bridge_info));
 227
 228         for (i=0; i<ETH_ALEN; i++)
 229                 id |= (u64)dev->dev_addr[i] << (8*(ETH_ALEN-1 - i));
 230         b.bridge_id = cpu_to_be64(id);
 231         b.stp_enabled = 0;
 232
 233         if (copy_to_user(ub, &b, sizeof(struct __bridge_info)))
 234                 return -EFAULT;
 235
 236         return 0;
 237 }
 238
 239 static int
 240 brc_get_port_list(struct net_device *dev, int __user *uindices, int num)
 241 {
 242         struct dp_dev *dp_dev = netdev_priv(dev);
 243         struct datapath *dp = dp_dev->dp;
 244         int *indices;
 245
 246         if (num < 0)
 247                 return -EINVAL;
 248         if (num == 0)
 249                 num = 256;
 250         if (num > DP_MAX_PORTS)
 251                 num = DP_MAX_PORTS;
 252
 253         indices = kcalloc(num, sizeof(int), GFP_KERNEL);
 254         if (indices == NULL)
 255                 return -ENOMEM;
 256
 257         get_port_ifindices(dp, indices, num);
 258         if (copy_to_user(uindices, indices, num * sizeof(int)))
 259                 num = -EFAULT;
 260         kfree(indices);
 261         return num;
 262 }
 263
 264 /* Legacy ioctl's through SIOCDEVPRIVATE.  Called with rtnl_lock. */
 265 static int
 266 old_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 267 {
 268         unsigned long args[4];
 269
 270         if (copy_from_user(args, rq->ifr_data, sizeof(args)))
 271                 return -EFAULT;
 272
 273         switch (args[0]) {
 274         case BRCTL_ADD_IF:
 275                 return brc_add_del_port(dev, args[1], 1);
 276         case BRCTL_DEL_IF:
 277                 return brc_add_del_port(dev, args[1], 0);
 278
 279         case BRCTL_GET_BRIDGE_INFO:
 280                 return brc_get_bridge_info(dev, (struct __bridge_info __user *)args[1]);
 281
 282         case BRCTL_GET_PORT_LIST:
 283                 return brc_get_port_list(dev, (int __user *)args[1], args[2]);
 284         }
 285
 286         return -EOPNOTSUPP;
 287 }
 288
 289 /* Called with the rtnl_lock. */
 290 static int
 291 brc_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 292 {
 293         int err;
 294
 295         switch (cmd) {
 296                 case SIOCDEVPRIVATE:
 297                         err = old_dev_ioctl(dev, rq, cmd);
 298                         break;
 299
 300                 case SIOCBRADDIF:
 301                         return brc_add_del_port(dev, rq->ifr_ifindex, 1);
 302                 case SIOCBRDELIF:
 303                         return brc_add_del_port(dev, rq->ifr_ifindex, 0);
 304
 305                 default:
 306                         err = -EOPNOTSUPP;
 307                         break;
 308         }
 309
 310         return err;
 311 }
 312
 313
 314 static struct genl_family brc_genl_family = {
 315         .id = GENL_ID_GENERATE,
 316         .hdrsize = 0,
 317         .name = BRC_GENL_FAMILY_NAME,
 318         .version = 1,
 319         .maxattr = BRC_GENL_A_MAX,
 320 };
 321
 322 static int brc_genl_query(struct sk_buff *skb, struct genl_info *info)
 323 {
 324         int err = -EINVAL;
 325         struct sk_buff *ans_skb;
 326         void *data;
 327
 328         ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 329         if (!ans_skb)
 330                 return -ENOMEM;
 331
 332         data = genlmsg_put_reply(ans_skb, info, &brc_genl_family,
 333                                  0, BRC_GENL_C_QUERY_MC);
 334         if (data == NULL) {
 335                 err = -ENOMEM;
 336                 goto err;
 337         }
 338         NLA_PUT_U32(ans_skb, BRC_GENL_A_MC_GROUP, brc_mc_group.id);
 339
 340         genlmsg_end(ans_skb, data);
 341         return genlmsg_reply(ans_skb, info);
 342
 343 err:
 344 nla_put_failure:
 345         kfree_skb(ans_skb);
 346         return err;
 347 }
 348
 349 static struct genl_ops brc_genl_ops_query_dp = {
 350         .cmd = BRC_GENL_C_QUERY_MC,
 351         .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privelege. */
 352         .policy = NULL,
 353         .doit = brc_genl_query,
 354         .dumpit = NULL
 355 };
 356
 357 /* Attribute policy: what each attribute may contain.  */
 358 static struct nla_policy brc_genl_policy[BRC_GENL_A_MAX + 1] = {
 359         [BRC_GENL_A_ERR_CODE] = { .type = NLA_U32 },
 360         [BRC_GENL_A_PROC_DIR] = { .type = NLA_NUL_STRING },
 361         [BRC_GENL_A_PROC_NAME] = { .type = NLA_NUL_STRING },
 362         [BRC_GENL_A_PROC_DATA] = { .type = NLA_NUL_STRING },
 363 };
 364
 365 static int
 366 brc_genl_dp_result(struct sk_buff *skb, struct genl_info *info)
 367 {
 368         unsigned long int flags;
 369         int err;
 370
 371         if (!info->attrs[BRC_GENL_A_ERR_CODE])
 372                 return -EINVAL;
 373
 374         skb = skb_clone(skb, GFP_KERNEL);
 375         if (!skb)
 376                 return -ENOMEM;
 377
 378         spin_lock_irqsave(&brc_lock, flags);
 379         if (brc_seq == info->snd_seq) {
 380                 brc_seq++;
 381
 382                 if (brc_reply)
 383                         kfree_skb(brc_reply);
 384                 brc_reply = skb;
 385
 386                 complete(&brc_done);
 387                 err = 0;
 388         } else {
 389                 kfree_skb(skb);
 390                 err = -ESTALE;
 391         }
 392         spin_unlock_irqrestore(&brc_lock, flags);
 393
 394         return err;
 395 }
 396
 397 static struct genl_ops brc_genl_ops_dp_result = {
 398         .cmd = BRC_GENL_C_DP_RESULT,
 399         .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privelege. */
 400         .policy = brc_genl_policy,
 401         .doit = brc_genl_dp_result,
 402         .dumpit = NULL
 403 };
 404
 405 static struct genl_ops brc_genl_ops_set_proc = {
 406         .cmd = BRC_GENL_C_SET_PROC,
 407         .flags = GENL_ADMIN_PERM, /* Requires CAP_NET_ADMIN privelege. */
 408         .policy = brc_genl_policy,
 409         .doit = brc_genl_set_proc,
 410         .dumpit = NULL
 411 };
 412
 413 static struct sk_buff *brc_send_command(struct sk_buff *request, struct nlattr **attrs)
 414 {
 415         unsigned long int flags;
 416         struct sk_buff *reply;
 417         int error;
 418
 419         mutex_lock(&brc_serial);
 420
 421         /* Increment sequence number first, so that we ignore any replies
 422          * to stale requests. */
 423         spin_lock_irqsave(&brc_lock, flags);
 424         nlmsg_hdr(request)->nlmsg_seq = ++brc_seq;
 425         INIT_COMPLETION(brc_done);
 426         spin_unlock_irqrestore(&brc_lock, flags);
 427
 428         nlmsg_end(request, nlmsg_hdr(request));
 429
 430         /* Send message. */
 431         error = genlmsg_multicast(request, 0, brc_mc_group.id, GFP_KERNEL);
 432         if (error < 0)
 433                 goto error;
 434
 435         /* Wait for reply. */
 436         error = -ETIMEDOUT;
 437         if (!wait_for_completion_timeout(&brc_done, BRC_TIMEOUT))
 438                 goto error;
 439
 440         /* Grab reply. */
 441         spin_lock_irqsave(&brc_lock, flags);
 442         reply = brc_reply;
 443         brc_reply = NULL;
 444         spin_unlock_irqrestore(&brc_lock, flags);
 445
 446         mutex_unlock(&brc_serial);
 447
 448         /* Re-parse message.  Can't fail, since it parsed correctly once
 449          * already. */
 450         error = nlmsg_parse(nlmsg_hdr(reply), GENL_HDRLEN,
 451                             attrs, BRC_GENL_A_MAX, brc_genl_policy);
 452         WARN_ON(error);
 453
 454         return reply;
 455
 456 error:
 457         mutex_unlock(&brc_serial);
 458         return ERR_PTR(error);
 459 }
 460
 461 int brc_add_dp(struct datapath *dp)
 462 {
 463         if (!try_module_get(THIS_MODULE))
 464                 return -ENODEV;
 465 #ifdef SUPPORT_SYSFS
 466         brc_sysfs_add_dp(dp);
 467 #endif
 468
 469         return 0;
 470 }
 471
 472 int brc_del_dp(struct datapath *dp)
 473 {
 474 #ifdef SUPPORT_SYSFS
 475         brc_sysfs_del_dp(dp);
 476 #endif
 477         module_put(THIS_MODULE);
 478
 479         return 0;
 480 }
 481
 482 static int
 483 __init brc_init(void)
 484 {
 485         int i;
 486         int err;
 487
 488         printk("Open vSwitch Bridge Compatibility, built "__DATE__" "__TIME__"\n");
 489
 490         rcu_read_lock();
 491         for (i=0; i<ODP_MAX; i++) {
 492                 if (get_dp(i)) {
 493                         rcu_read_unlock();
 494                         printk(KERN_EMERG "brcompat: no datapaths may exist!\n");
 495                         return -EEXIST;
 496                 }
 497         }
 498         rcu_read_unlock();
 499
 500         /* Set the bridge ioctl handler */
 501         brioctl_set(brc_ioctl_deviceless_stub);
 502
 503         /* Set the openvswitch_mod device ioctl handler */
 504         dp_ioctl_hook = brc_dev_ioctl;
 505
 506         /* Register hooks for datapath adds and deletes */
 507         dp_add_dp_hook = brc_add_dp;
 508         dp_del_dp_hook = brc_del_dp;
 509
 510         /* Register hooks for interface adds and deletes */
 511 #ifdef SUPPORT_SYSFS
 512         dp_add_if_hook = brc_sysfs_add_if;
 513         dp_del_if_hook = brc_sysfs_del_if;
 514 #endif
 515
 516         /* Randomize the initial sequence number.  This is not a security
 517          * feature; it only helps avoid crossed wires between userspace and
 518          * the kernel when the module is unloaded and reloaded. */
 519         brc_seq = net_random();
 520
 521         /* Register generic netlink family to communicate changes to
 522          * userspace. */
 523         err = genl_register_family(&brc_genl_family);
 524         if (err)
 525                 goto error;
 526
 527         err = genl_register_ops(&brc_genl_family, &brc_genl_ops_query_dp);
 528         if (err != 0)
 529                 goto err_unregister;
 530
 531         err = genl_register_ops(&brc_genl_family, &brc_genl_ops_dp_result);
 532         if (err != 0)
 533                 goto err_unregister;
 534
 535         err = genl_register_ops(&brc_genl_family, &brc_genl_ops_set_proc);
 536         if (err != 0)
 537                 goto err_unregister;
 538
 539         strcpy(brc_mc_group.name, "brcompat");
 540         err = genl_register_mc_group(&brc_genl_family, &brc_mc_group);
 541         if (err < 0)
 542                 goto err_unregister;
 543
 544         return 0;
 545
 546 err_unregister:
 547         genl_unregister_family(&brc_genl_family);
 548 error:
 549         printk(KERN_EMERG "brcompat: failed to install!");
 550         return err;
 551 }
 552
 553 static void
 554 brc_cleanup(void)
 555 {
 556         /* Unregister hooks for datapath adds and deletes */
 557         dp_add_dp_hook = NULL;
 558         dp_del_dp_hook = NULL;
 559
 560         /* Unregister hooks for interface adds and deletes */
 561         dp_add_if_hook = NULL;
 562         dp_del_if_hook = NULL;
 563
 564         /* Unregister ioctl hooks */
 565         dp_ioctl_hook = NULL;
 566         brioctl_set(NULL);
 567
 568         genl_unregister_family(&brc_genl_family);
 569         brc_procfs_exit();
 570 }
 571
 572 module_init(brc_init);
 573 module_exit(brc_cleanup);
 574
 575 MODULE_DESCRIPTION("Open vSwitch bridge compatibility");
 576 MODULE_AUTHOR("Nicira Networks");
 577 MODULE_LICENSE("GPL");