1 /* 2 * vrf.c: device driver to encapsulate a VRF space 3 * 4 * Copyright (c) 2015 Cumulus Networks. All rights reserved. 5 * Copyright (c) 2015 Shrijeet Mukherjee <shm@cumulusnetworks.com> 6 * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com> 7 * 8 * Based on dummy, team and ipvlan drivers 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License as published by 12 * the Free Software Foundation; either version 2 of the License, or 13 * (at your option) any later version. 14 */ 15 16 #include <linux/module.h> 17 #include <linux/kernel.h> 18 #include <linux/netdevice.h> 19 #include <linux/etherdevice.h> 20 #include <linux/ip.h> 21 #include <linux/init.h> 22 #include <linux/moduleparam.h> 23 #include <linux/netfilter.h> 24 #include <linux/rtnetlink.h> 25 #include <net/rtnetlink.h> 26 #include <linux/u64_stats_sync.h> 27 #include <linux/hashtable.h> 28 29 #include <linux/inetdevice.h> 30 #include <net/arp.h> 31 #include <net/ip.h> 32 #include <net/ip_fib.h> 33 #include <net/ip6_route.h> 34 #include <net/rtnetlink.h> 35 #include <net/route.h> 36 #include <net/addrconf.h> 37 #include <net/vrf.h> 38 39 #define DRV_NAME "vrf" 40 #define DRV_VERSION "1.0" 41 42 #define vrf_is_slave(dev) ((dev)->flags & IFF_SLAVE) 43 44 #define vrf_master_get_rcu(dev) \ 45 ((struct net_device *)rcu_dereference(dev->rx_handler_data)) 46 47 struct pcpu_dstats { 48 u64 tx_pkts; 49 u64 tx_bytes; 50 u64 tx_drps; 51 u64 rx_pkts; 52 u64 rx_bytes; 53 struct u64_stats_sync syncp; 54 }; 55 56 static struct dst_entry *vrf_ip_check(struct dst_entry *dst, u32 cookie) 57 { 58 return dst; 59 } 60 61 static int vrf_ip_local_out(struct sk_buff *skb) 62 { 63 return ip_local_out(skb); 64 } 65 66 static unsigned int vrf_v4_mtu(const struct dst_entry *dst) 67 { 68 /* TO-DO: return max ethernet size? */ 69 return dst->dev->mtu; 70 } 71 72 static void vrf_dst_destroy(struct dst_entry *dst) 73 { 74 /* our dst lives forever - or until the device is closed */ 75 } 76 77 static unsigned int vrf_default_advmss(const struct dst_entry *dst) 78 { 79 return 65535 - 40; 80 } 81 82 static struct dst_ops vrf_dst_ops = { 83 .family = AF_INET, 84 .local_out = vrf_ip_local_out, 85 .check = vrf_ip_check, 86 .mtu = vrf_v4_mtu, 87 .destroy = vrf_dst_destroy, 88 .default_advmss = vrf_default_advmss, 89 }; 90 91 static bool is_ip_rx_frame(struct sk_buff *skb) 92 { 93 switch (skb->protocol) { 94 case htons(ETH_P_IP): 95 case htons(ETH_P_IPV6): 96 return true; 97 } 98 return false; 99 } 100 101 static void vrf_tx_error(struct net_device *vrf_dev, struct sk_buff *skb) 102 { 103 vrf_dev->stats.tx_errors++; 104 kfree_skb(skb); 105 } 106 107 /* note: already called with rcu_read_lock */ 108 static rx_handler_result_t vrf_handle_frame(struct sk_buff **pskb) 109 { 110 struct sk_buff *skb = *pskb; 111 112 if (is_ip_rx_frame(skb)) { 113 struct net_device *dev = vrf_master_get_rcu(skb->dev); 114 struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats); 115 116 u64_stats_update_begin(&dstats->syncp); 117 dstats->rx_pkts++; 118 dstats->rx_bytes += skb->len; 119 u64_stats_update_end(&dstats->syncp); 120 121 skb->dev = dev; 122 123 return RX_HANDLER_ANOTHER; 124 } 125 return RX_HANDLER_PASS; 126 } 127 128 static struct rtnl_link_stats64 *vrf_get_stats64(struct net_device *dev, 129 struct rtnl_link_stats64 *stats) 130 { 131 int i; 132 133 for_each_possible_cpu(i) { 134 const struct pcpu_dstats *dstats; 135 u64 tbytes, tpkts, tdrops, rbytes, rpkts; 136 unsigned int start; 137 138 dstats = per_cpu_ptr(dev->dstats, i); 139 do { 140 start = u64_stats_fetch_begin_irq(&dstats->syncp); 141 tbytes = dstats->tx_bytes; 142 tpkts = dstats->tx_pkts; 143 tdrops = dstats->tx_drps; 144 rbytes = dstats->rx_bytes; 145 rpkts = dstats->rx_pkts; 146 } while (u64_stats_fetch_retry_irq(&dstats->syncp, start)); 147 stats->tx_bytes += tbytes; 148 stats->tx_packets += tpkts; 149 stats->tx_dropped += tdrops; 150 stats->rx_bytes += rbytes; 151 stats->rx_packets += rpkts; 152 } 153 return stats; 154 } 155 156 static netdev_tx_t vrf_process_v6_outbound(struct sk_buff *skb, 157 struct net_device *dev) 158 { 159 vrf_tx_error(dev, skb); 160 return NET_XMIT_DROP; 161 } 162 163 static int vrf_send_v4_prep(struct sk_buff *skb, struct flowi4 *fl4, 164 struct net_device *vrf_dev) 165 { 166 struct rtable *rt; 167 int err = 1; 168 169 rt = ip_route_output_flow(dev_net(vrf_dev), fl4, NULL); 170 if (IS_ERR(rt)) 171 goto out; 172 173 /* TO-DO: what about broadcast ? */ 174 if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) { 175 ip_rt_put(rt); 176 goto out; 177 } 178 179 skb_dst_drop(skb); 180 skb_dst_set(skb, &rt->dst); 181 err = 0; 182 out: 183 return err; 184 } 185 186 static netdev_tx_t vrf_process_v4_outbound(struct sk_buff *skb, 187 struct net_device *vrf_dev) 188 { 189 struct iphdr *ip4h = ip_hdr(skb); 190 int ret = NET_XMIT_DROP; 191 struct flowi4 fl4 = { 192 /* needed to match OIF rule */ 193 .flowi4_oif = vrf_dev->ifindex, 194 .flowi4_iif = LOOPBACK_IFINDEX, 195 .flowi4_tos = RT_TOS(ip4h->tos), 196 .flowi4_flags = FLOWI_FLAG_ANYSRC | FLOWI_FLAG_VRFSRC, 197 .daddr = ip4h->daddr, 198 }; 199 200 if (vrf_send_v4_prep(skb, &fl4, vrf_dev)) 201 goto err; 202 203 if (!ip4h->saddr) { 204 ip4h->saddr = inet_select_addr(skb_dst(skb)->dev, 0, 205 RT_SCOPE_LINK); 206 } 207 208 ret = ip_local_out(skb); 209 if (unlikely(net_xmit_eval(ret))) 210 vrf_dev->stats.tx_errors++; 211 else 212 ret = NET_XMIT_SUCCESS; 213 214 out: 215 return ret; 216 err: 217 vrf_tx_error(vrf_dev, skb); 218 goto out; 219 } 220 221 static netdev_tx_t is_ip_tx_frame(struct sk_buff *skb, struct net_device *dev) 222 { 223 /* strip the ethernet header added for pass through VRF device */ 224 __skb_pull(skb, skb_network_offset(skb)); 225 226 switch (skb->protocol) { 227 case htons(ETH_P_IP): 228 return vrf_process_v4_outbound(skb, dev); 229 case htons(ETH_P_IPV6): 230 return vrf_process_v6_outbound(skb, dev); 231 default: 232 vrf_tx_error(dev, skb); 233 return NET_XMIT_DROP; 234 } 235 } 236 237 static netdev_tx_t vrf_xmit(struct sk_buff *skb, struct net_device *dev) 238 { 239 netdev_tx_t ret = is_ip_tx_frame(skb, dev); 240 241 if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) { 242 struct pcpu_dstats *dstats = this_cpu_ptr(dev->dstats); 243 244 u64_stats_update_begin(&dstats->syncp); 245 dstats->tx_pkts++; 246 dstats->tx_bytes += skb->len; 247 u64_stats_update_end(&dstats->syncp); 248 } else { 249 this_cpu_inc(dev->dstats->tx_drps); 250 } 251 252 return ret; 253 } 254 255 /* modelled after ip_finish_output2 */ 256 static int vrf_finish_output(struct sock *sk, struct sk_buff *skb) 257 { 258 struct dst_entry *dst = skb_dst(skb); 259 struct rtable *rt = (struct rtable *)dst; 260 struct net_device *dev = dst->dev; 261 unsigned int hh_len = LL_RESERVED_SPACE(dev); 262 struct neighbour *neigh; 263 u32 nexthop; 264 int ret = -EINVAL; 265 266 /* Be paranoid, rather than too clever. */ 267 if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { 268 struct sk_buff *skb2; 269 270 skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev)); 271 if (!skb2) { 272 ret = -ENOMEM; 273 goto err; 274 } 275 if (skb->sk) 276 skb_set_owner_w(skb2, skb->sk); 277 278 consume_skb(skb); 279 skb = skb2; 280 } 281 282 rcu_read_lock_bh(); 283 284 nexthop = (__force u32)rt_nexthop(rt, ip_hdr(skb)->daddr); 285 neigh = __ipv4_neigh_lookup_noref(dev, nexthop); 286 if (unlikely(!neigh)) 287 neigh = __neigh_create(&arp_tbl, &nexthop, dev, false); 288 if (!IS_ERR(neigh)) 289 ret = dst_neigh_output(dst, neigh, skb); 290 291 rcu_read_unlock_bh(); 292 err: 293 if (unlikely(ret < 0)) 294 vrf_tx_error(skb->dev, skb); 295 return ret; 296 } 297 298 static int vrf_output(struct sock *sk, struct sk_buff *skb) 299 { 300 struct net_device *dev = skb_dst(skb)->dev; 301 302 IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUT, skb->len); 303 304 skb->dev = dev; 305 skb->protocol = htons(ETH_P_IP); 306 307 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb, 308 NULL, dev, 309 vrf_finish_output, 310 !(IPCB(skb)->flags & IPSKB_REROUTED)); 311 } 312 313 static void vrf_rtable_destroy(struct net_vrf *vrf) 314 { 315 struct dst_entry *dst = (struct dst_entry *)vrf->rth; 316 317 dst_destroy(dst); 318 vrf->rth = NULL; 319 } 320 321 static struct rtable *vrf_rtable_create(struct net_device *dev) 322 { 323 struct rtable *rth; 324 325 rth = dst_alloc(&vrf_dst_ops, dev, 2, 326 DST_OBSOLETE_NONE, 327 (DST_HOST | DST_NOPOLICY | DST_NOXFRM)); 328 if (rth) { 329 rth->dst.output = vrf_output; 330 rth->rt_genid = rt_genid_ipv4(dev_net(dev)); 331 rth->rt_flags = 0; 332 rth->rt_type = RTN_UNICAST; 333 rth->rt_is_input = 0; 334 rth->rt_iif = 0; 335 rth->rt_pmtu = 0; 336 rth->rt_gateway = 0; 337 rth->rt_uses_gateway = 0; 338 INIT_LIST_HEAD(&rth->rt_uncached); 339 rth->rt_uncached_list = NULL; 340 } 341 342 return rth; 343 } 344 345 /**************************** device handling ********************/ 346 347 /* cycle interface to flush neighbor cache and move routes across tables */ 348 static void cycle_netdev(struct net_device *dev) 349 { 350 unsigned int flags = dev->flags; 351 int ret; 352 353 if (!netif_running(dev)) 354 return; 355 356 ret = dev_change_flags(dev, flags & ~IFF_UP); 357 if (ret >= 0) 358 ret = dev_change_flags(dev, flags); 359 360 if (ret < 0) { 361 netdev_err(dev, 362 "Failed to cycle device %s; route tables might be wrong!\n", 363 dev->name); 364 } 365 } 366 367 static struct slave *__vrf_find_slave_dev(struct slave_queue *queue, 368 struct net_device *dev) 369 { 370 struct list_head *head = &queue->all_slaves; 371 struct slave *slave; 372 373 list_for_each_entry(slave, head, list) { 374 if (slave->dev == dev) 375 return slave; 376 } 377 378 return NULL; 379 } 380 381 /* inverse of __vrf_insert_slave */ 382 static void __vrf_remove_slave(struct slave_queue *queue, struct slave *slave) 383 { 384 list_del(&slave->list); 385 } 386 387 static void __vrf_insert_slave(struct slave_queue *queue, struct slave *slave) 388 { 389 list_add(&slave->list, &queue->all_slaves); 390 } 391 392 static int do_vrf_add_slave(struct net_device *dev, struct net_device *port_dev) 393 { 394 struct net_vrf_dev *vrf_ptr = kmalloc(sizeof(*vrf_ptr), GFP_KERNEL); 395 struct slave *slave = kzalloc(sizeof(*slave), GFP_KERNEL); 396 struct net_vrf *vrf = netdev_priv(dev); 397 struct slave_queue *queue = &vrf->queue; 398 int ret = -ENOMEM; 399 400 if (!slave || !vrf_ptr) 401 goto out_fail; 402 403 slave->dev = port_dev; 404 vrf_ptr->ifindex = dev->ifindex; 405 vrf_ptr->tb_id = vrf->tb_id; 406 407 /* register the packet handler for slave ports */ 408 ret = netdev_rx_handler_register(port_dev, vrf_handle_frame, dev); 409 if (ret) { 410 netdev_err(port_dev, 411 "Device %s failed to register rx_handler\n", 412 port_dev->name); 413 goto out_fail; 414 } 415 416 ret = netdev_master_upper_dev_link(port_dev, dev); 417 if (ret < 0) 418 goto out_unregister; 419 420 port_dev->flags |= IFF_SLAVE; 421 __vrf_insert_slave(queue, slave); 422 rcu_assign_pointer(port_dev->vrf_ptr, vrf_ptr); 423 cycle_netdev(port_dev); 424 425 return 0; 426 427 out_unregister: 428 netdev_rx_handler_unregister(port_dev); 429 out_fail: 430 kfree(vrf_ptr); 431 kfree(slave); 432 return ret; 433 } 434 435 static int vrf_add_slave(struct net_device *dev, struct net_device *port_dev) 436 { 437 if (netif_is_vrf(port_dev) || vrf_is_slave(port_dev)) 438 return -EINVAL; 439 440 return do_vrf_add_slave(dev, port_dev); 441 } 442 443 /* inverse of do_vrf_add_slave */ 444 static int do_vrf_del_slave(struct net_device *dev, struct net_device *port_dev) 445 { 446 struct net_vrf_dev *vrf_ptr = rtnl_dereference(port_dev->vrf_ptr); 447 struct net_vrf *vrf = netdev_priv(dev); 448 struct slave_queue *queue = &vrf->queue; 449 struct slave *slave; 450 451 RCU_INIT_POINTER(port_dev->vrf_ptr, NULL); 452 453 netdev_upper_dev_unlink(port_dev, dev); 454 port_dev->flags &= ~IFF_SLAVE; 455 456 netdev_rx_handler_unregister(port_dev); 457 458 /* after netdev_rx_handler_unregister for synchronize_rcu */ 459 kfree(vrf_ptr); 460 461 cycle_netdev(port_dev); 462 463 slave = __vrf_find_slave_dev(queue, port_dev); 464 if (slave) 465 __vrf_remove_slave(queue, slave); 466 467 kfree(slave); 468 469 return 0; 470 } 471 472 static int vrf_del_slave(struct net_device *dev, struct net_device *port_dev) 473 { 474 return do_vrf_del_slave(dev, port_dev); 475 } 476 477 static void vrf_dev_uninit(struct net_device *dev) 478 { 479 struct net_vrf *vrf = netdev_priv(dev); 480 struct slave_queue *queue = &vrf->queue; 481 struct list_head *head = &queue->all_slaves; 482 struct slave *slave, *next; 483 484 vrf_rtable_destroy(vrf); 485 486 list_for_each_entry_safe(slave, next, head, list) 487 vrf_del_slave(dev, slave->dev); 488 489 free_percpu(dev->dstats); 490 dev->dstats = NULL; 491 } 492 493 static int vrf_dev_init(struct net_device *dev) 494 { 495 struct net_vrf *vrf = netdev_priv(dev); 496 497 INIT_LIST_HEAD(&vrf->queue.all_slaves); 498 499 dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats); 500 if (!dev->dstats) 501 goto out_nomem; 502 503 /* create the default dst which points back to us */ 504 vrf->rth = vrf_rtable_create(dev); 505 if (!vrf->rth) 506 goto out_stats; 507 508 dev->flags = IFF_MASTER | IFF_NOARP; 509 510 return 0; 511 512 out_stats: 513 free_percpu(dev->dstats); 514 dev->dstats = NULL; 515 out_nomem: 516 return -ENOMEM; 517 } 518 519 static const struct net_device_ops vrf_netdev_ops = { 520 .ndo_init = vrf_dev_init, 521 .ndo_uninit = vrf_dev_uninit, 522 .ndo_start_xmit = vrf_xmit, 523 .ndo_get_stats64 = vrf_get_stats64, 524 .ndo_add_slave = vrf_add_slave, 525 .ndo_del_slave = vrf_del_slave, 526 }; 527 528 static void vrf_get_drvinfo(struct net_device *dev, 529 struct ethtool_drvinfo *info) 530 { 531 strlcpy(info->driver, DRV_NAME, sizeof(info->driver)); 532 strlcpy(info->version, DRV_VERSION, sizeof(info->version)); 533 } 534 535 static const struct ethtool_ops vrf_ethtool_ops = { 536 .get_drvinfo = vrf_get_drvinfo, 537 }; 538 539 static void vrf_setup(struct net_device *dev) 540 { 541 ether_setup(dev); 542 543 /* Initialize the device structure. */ 544 dev->netdev_ops = &vrf_netdev_ops; 545 dev->ethtool_ops = &vrf_ethtool_ops; 546 dev->destructor = free_netdev; 547 548 /* Fill in device structure with ethernet-generic values. */ 549 eth_hw_addr_random(dev); 550 551 /* don't acquire vrf device's netif_tx_lock when transmitting */ 552 dev->features |= NETIF_F_LLTX; 553 554 /* don't allow vrf devices to change network namespaces. */ 555 dev->features |= NETIF_F_NETNS_LOCAL; 556 } 557 558 static int vrf_validate(struct nlattr *tb[], struct nlattr *data[]) 559 { 560 if (tb[IFLA_ADDRESS]) { 561 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 562 return -EINVAL; 563 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 564 return -EADDRNOTAVAIL; 565 } 566 return 0; 567 } 568 569 static void vrf_dellink(struct net_device *dev, struct list_head *head) 570 { 571 struct net_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr); 572 573 RCU_INIT_POINTER(dev->vrf_ptr, NULL); 574 kfree_rcu(vrf_ptr, rcu); 575 unregister_netdevice_queue(dev, head); 576 } 577 578 static int vrf_newlink(struct net *src_net, struct net_device *dev, 579 struct nlattr *tb[], struct nlattr *data[]) 580 { 581 struct net_vrf *vrf = netdev_priv(dev); 582 struct net_vrf_dev *vrf_ptr; 583 int err; 584 585 if (!data || !data[IFLA_VRF_TABLE]) 586 return -EINVAL; 587 588 vrf->tb_id = nla_get_u32(data[IFLA_VRF_TABLE]); 589 590 dev->priv_flags |= IFF_VRF_MASTER; 591 592 err = -ENOMEM; 593 vrf_ptr = kmalloc(sizeof(*dev->vrf_ptr), GFP_KERNEL); 594 if (!vrf_ptr) 595 goto out_fail; 596 597 vrf_ptr->ifindex = dev->ifindex; 598 vrf_ptr->tb_id = vrf->tb_id; 599 600 err = register_netdevice(dev); 601 if (err < 0) 602 goto out_fail; 603 604 rcu_assign_pointer(dev->vrf_ptr, vrf_ptr); 605 606 return 0; 607 608 out_fail: 609 kfree(vrf_ptr); 610 free_netdev(dev); 611 return err; 612 } 613 614 static size_t vrf_nl_getsize(const struct net_device *dev) 615 { 616 return nla_total_size(sizeof(u32)); /* IFLA_VRF_TABLE */ 617 } 618 619 static int vrf_fillinfo(struct sk_buff *skb, 620 const struct net_device *dev) 621 { 622 struct net_vrf *vrf = netdev_priv(dev); 623 624 return nla_put_u32(skb, IFLA_VRF_TABLE, vrf->tb_id); 625 } 626 627 static const struct nla_policy vrf_nl_policy[IFLA_VRF_MAX + 1] = { 628 [IFLA_VRF_TABLE] = { .type = NLA_U32 }, 629 }; 630 631 static struct rtnl_link_ops vrf_link_ops __read_mostly = { 632 .kind = DRV_NAME, 633 .priv_size = sizeof(struct net_vrf), 634 635 .get_size = vrf_nl_getsize, 636 .policy = vrf_nl_policy, 637 .validate = vrf_validate, 638 .fill_info = vrf_fillinfo, 639 640 .newlink = vrf_newlink, 641 .dellink = vrf_dellink, 642 .setup = vrf_setup, 643 .maxtype = IFLA_VRF_MAX, 644 }; 645 646 static int vrf_device_event(struct notifier_block *unused, 647 unsigned long event, void *ptr) 648 { 649 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 650 651 /* only care about unregister events to drop slave references */ 652 if (event == NETDEV_UNREGISTER) { 653 struct net_vrf_dev *vrf_ptr = rtnl_dereference(dev->vrf_ptr); 654 struct net_device *vrf_dev; 655 656 if (!vrf_ptr || netif_is_vrf(dev)) 657 goto out; 658 659 vrf_dev = netdev_master_upper_dev_get(dev); 660 vrf_del_slave(vrf_dev, dev); 661 } 662 out: 663 return NOTIFY_DONE; 664 } 665 666 static struct notifier_block vrf_notifier_block __read_mostly = { 667 .notifier_call = vrf_device_event, 668 }; 669 670 static int __init vrf_init_module(void) 671 { 672 int rc; 673 674 vrf_dst_ops.kmem_cachep = 675 kmem_cache_create("vrf_ip_dst_cache", 676 sizeof(struct rtable), 0, 677 SLAB_HWCACHE_ALIGN, 678 NULL); 679 680 if (!vrf_dst_ops.kmem_cachep) 681 return -ENOMEM; 682 683 register_netdevice_notifier(&vrf_notifier_block); 684 685 rc = rtnl_link_register(&vrf_link_ops); 686 if (rc < 0) 687 goto error; 688 689 return 0; 690 691 error: 692 unregister_netdevice_notifier(&vrf_notifier_block); 693 kmem_cache_destroy(vrf_dst_ops.kmem_cachep); 694 return rc; 695 } 696 697 static void __exit vrf_cleanup_module(void) 698 { 699 rtnl_link_unregister(&vrf_link_ops); 700 unregister_netdevice_notifier(&vrf_notifier_block); 701 kmem_cache_destroy(vrf_dst_ops.kmem_cachep); 702 } 703 704 module_init(vrf_init_module); 705 module_exit(vrf_cleanup_module); 706 MODULE_AUTHOR("Shrijeet Mukherjee, David Ahern"); 707 MODULE_DESCRIPTION("Device driver to instantiate VRF domains"); 708 MODULE_LICENSE("GPL"); 709 MODULE_ALIAS_RTNL_LINK(DRV_NAME); 710 MODULE_VERSION(DRV_VERSION); 711