1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2023 Isovalent */ 3 4 #include <linux/netdevice.h> 5 #include <linux/ethtool.h> 6 #include <linux/etherdevice.h> 7 #include <linux/filter.h> 8 #include <linux/netfilter_netdev.h> 9 #include <linux/bpf_mprog.h> 10 #include <linux/indirect_call_wrapper.h> 11 12 #include <net/netkit.h> 13 #include <net/dst.h> 14 #include <net/tcx.h> 15 16 #define DRV_NAME "netkit" 17 18 struct netkit { 19 /* Needed in fast-path */ 20 struct net_device __rcu *peer; 21 struct bpf_mprog_entry __rcu *active; 22 enum netkit_action policy; 23 struct bpf_mprog_bundle bundle; 24 25 /* Needed in slow-path */ 26 enum netkit_mode mode; 27 bool primary; 28 u32 headroom; 29 }; 30 31 struct netkit_link { 32 struct bpf_link link; 33 struct net_device *dev; 34 u32 location; 35 }; 36 37 static __always_inline int 38 netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb, 39 enum netkit_action ret) 40 { 41 const struct bpf_mprog_fp *fp; 42 const struct bpf_prog *prog; 43 44 bpf_mprog_foreach_prog(entry, fp, prog) { 45 bpf_compute_data_pointers(skb); 46 ret = bpf_prog_run(prog, skb); 47 if (ret != NETKIT_NEXT) 48 break; 49 } 50 return ret; 51 } 52 53 static void netkit_prep_forward(struct sk_buff *skb, bool xnet) 54 { 55 skb_scrub_packet(skb, xnet); 56 skb->priority = 0; 57 nf_skip_egress(skb, true); 58 skb_reset_mac_header(skb); 59 } 60 61 static struct netkit *netkit_priv(const struct net_device *dev) 62 { 63 return netdev_priv(dev); 64 } 65 66 static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev) 67 { 68 struct netkit *nk = netkit_priv(dev); 69 enum netkit_action ret = READ_ONCE(nk->policy); 70 netdev_tx_t ret_dev = NET_XMIT_SUCCESS; 71 const struct bpf_mprog_entry *entry; 72 struct net_device *peer; 73 int len = skb->len; 74 75 rcu_read_lock(); 76 peer = rcu_dereference(nk->peer); 77 if (unlikely(!peer || !(peer->flags & IFF_UP) || 78 !pskb_may_pull(skb, ETH_HLEN) || 79 skb_orphan_frags(skb, GFP_ATOMIC))) 80 goto drop; 81 netkit_prep_forward(skb, !net_eq(dev_net(dev), dev_net(peer))); 82 eth_skb_pkt_type(skb, peer); 83 skb->dev = peer; 84 entry = rcu_dereference(nk->active); 85 if (entry) 86 ret = netkit_run(entry, skb, ret); 87 switch (ret) { 88 case NETKIT_NEXT: 89 case NETKIT_PASS: 90 eth_skb_pull_mac(skb); 91 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); 92 if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) { 93 dev_sw_netstats_tx_add(dev, 1, len); 94 dev_sw_netstats_rx_add(peer, len); 95 } else { 96 goto drop_stats; 97 } 98 break; 99 case NETKIT_REDIRECT: 100 dev_sw_netstats_tx_add(dev, 1, len); 101 skb_do_redirect(skb); 102 break; 103 case NETKIT_DROP: 104 default: 105 drop: 106 kfree_skb(skb); 107 drop_stats: 108 dev_core_stats_tx_dropped_inc(dev); 109 ret_dev = NET_XMIT_DROP; 110 break; 111 } 112 rcu_read_unlock(); 113 return ret_dev; 114 } 115 116 static int netkit_open(struct net_device *dev) 117 { 118 struct netkit *nk = netkit_priv(dev); 119 struct net_device *peer = rtnl_dereference(nk->peer); 120 121 if (!peer) 122 return -ENOTCONN; 123 if (peer->flags & IFF_UP) { 124 netif_carrier_on(dev); 125 netif_carrier_on(peer); 126 } 127 return 0; 128 } 129 130 static int netkit_close(struct net_device *dev) 131 { 132 struct netkit *nk = netkit_priv(dev); 133 struct net_device *peer = rtnl_dereference(nk->peer); 134 135 netif_carrier_off(dev); 136 if (peer) 137 netif_carrier_off(peer); 138 return 0; 139 } 140 141 static int netkit_get_iflink(const struct net_device *dev) 142 { 143 struct netkit *nk = netkit_priv(dev); 144 struct net_device *peer; 145 int iflink = 0; 146 147 rcu_read_lock(); 148 peer = rcu_dereference(nk->peer); 149 if (peer) 150 iflink = READ_ONCE(peer->ifindex); 151 rcu_read_unlock(); 152 return iflink; 153 } 154 155 static void netkit_set_multicast(struct net_device *dev) 156 { 157 /* Nothing to do, we receive whatever gets pushed to us! */ 158 } 159 160 static int netkit_set_macaddr(struct net_device *dev, void *sa) 161 { 162 struct netkit *nk = netkit_priv(dev); 163 164 if (nk->mode != NETKIT_L2) 165 return -EOPNOTSUPP; 166 167 return eth_mac_addr(dev, sa); 168 } 169 170 static void netkit_set_headroom(struct net_device *dev, int headroom) 171 { 172 struct netkit *nk = netkit_priv(dev), *nk2; 173 struct net_device *peer; 174 175 if (headroom < 0) 176 headroom = NET_SKB_PAD; 177 178 rcu_read_lock(); 179 peer = rcu_dereference(nk->peer); 180 if (unlikely(!peer)) 181 goto out; 182 183 nk2 = netkit_priv(peer); 184 nk->headroom = headroom; 185 headroom = max(nk->headroom, nk2->headroom); 186 187 peer->needed_headroom = headroom; 188 dev->needed_headroom = headroom; 189 out: 190 rcu_read_unlock(); 191 } 192 193 INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev) 194 { 195 return rcu_dereference(netkit_priv(dev)->peer); 196 } 197 198 static void netkit_get_stats(struct net_device *dev, 199 struct rtnl_link_stats64 *stats) 200 { 201 dev_fetch_sw_netstats(stats, dev->tstats); 202 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped); 203 } 204 205 static void netkit_uninit(struct net_device *dev); 206 207 static const struct net_device_ops netkit_netdev_ops = { 208 .ndo_open = netkit_open, 209 .ndo_stop = netkit_close, 210 .ndo_start_xmit = netkit_xmit, 211 .ndo_set_rx_mode = netkit_set_multicast, 212 .ndo_set_rx_headroom = netkit_set_headroom, 213 .ndo_set_mac_address = netkit_set_macaddr, 214 .ndo_get_iflink = netkit_get_iflink, 215 .ndo_get_peer_dev = netkit_peer_dev, 216 .ndo_get_stats64 = netkit_get_stats, 217 .ndo_uninit = netkit_uninit, 218 .ndo_features_check = passthru_features_check, 219 }; 220 221 static void netkit_get_drvinfo(struct net_device *dev, 222 struct ethtool_drvinfo *info) 223 { 224 strscpy(info->driver, DRV_NAME, sizeof(info->driver)); 225 } 226 227 static const struct ethtool_ops netkit_ethtool_ops = { 228 .get_drvinfo = netkit_get_drvinfo, 229 }; 230 231 static void netkit_setup(struct net_device *dev) 232 { 233 static const netdev_features_t netkit_features_hw_vlan = 234 NETIF_F_HW_VLAN_CTAG_TX | 235 NETIF_F_HW_VLAN_CTAG_RX | 236 NETIF_F_HW_VLAN_STAG_TX | 237 NETIF_F_HW_VLAN_STAG_RX; 238 static const netdev_features_t netkit_features = 239 netkit_features_hw_vlan | 240 NETIF_F_SG | 241 NETIF_F_FRAGLIST | 242 NETIF_F_HW_CSUM | 243 NETIF_F_RXCSUM | 244 NETIF_F_SCTP_CRC | 245 NETIF_F_HIGHDMA | 246 NETIF_F_GSO_SOFTWARE | 247 NETIF_F_GSO_ENCAP_ALL; 248 249 ether_setup(dev); 250 dev->max_mtu = ETH_MAX_MTU; 251 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS; 252 253 dev->flags |= IFF_NOARP; 254 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 255 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 256 dev->priv_flags |= IFF_PHONY_HEADROOM; 257 dev->priv_flags |= IFF_NO_QUEUE; 258 259 dev->ethtool_ops = &netkit_ethtool_ops; 260 dev->netdev_ops = &netkit_netdev_ops; 261 262 dev->features |= netkit_features | NETIF_F_LLTX; 263 dev->hw_features = netkit_features; 264 dev->hw_enc_features = netkit_features; 265 dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE; 266 dev->vlan_features = dev->features & ~netkit_features_hw_vlan; 267 268 dev->needs_free_netdev = true; 269 270 netif_set_tso_max_size(dev, GSO_MAX_SIZE); 271 } 272 273 static struct net *netkit_get_link_net(const struct net_device *dev) 274 { 275 struct netkit *nk = netkit_priv(dev); 276 struct net_device *peer = rtnl_dereference(nk->peer); 277 278 return peer ? dev_net(peer) : dev_net(dev); 279 } 280 281 static int netkit_check_policy(int policy, struct nlattr *tb, 282 struct netlink_ext_ack *extack) 283 { 284 switch (policy) { 285 case NETKIT_PASS: 286 case NETKIT_DROP: 287 return 0; 288 default: 289 NL_SET_ERR_MSG_ATTR(extack, tb, 290 "Provided default xmit policy not supported"); 291 return -EINVAL; 292 } 293 } 294 295 static int netkit_check_mode(int mode, struct nlattr *tb, 296 struct netlink_ext_ack *extack) 297 { 298 switch (mode) { 299 case NETKIT_L2: 300 case NETKIT_L3: 301 return 0; 302 default: 303 NL_SET_ERR_MSG_ATTR(extack, tb, 304 "Provided device mode can only be L2 or L3"); 305 return -EINVAL; 306 } 307 } 308 309 static int netkit_validate(struct nlattr *tb[], struct nlattr *data[], 310 struct netlink_ext_ack *extack) 311 { 312 struct nlattr *attr = tb[IFLA_ADDRESS]; 313 314 if (!attr) 315 return 0; 316 if (nla_len(attr) != ETH_ALEN) 317 return -EINVAL; 318 if (!is_valid_ether_addr(nla_data(attr))) 319 return -EADDRNOTAVAIL; 320 return 0; 321 } 322 323 static struct rtnl_link_ops netkit_link_ops; 324 325 static int netkit_new_link(struct net *src_net, struct net_device *dev, 326 struct nlattr *tb[], struct nlattr *data[], 327 struct netlink_ext_ack *extack) 328 { 329 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb, *attr; 330 enum netkit_action default_prim = NETKIT_PASS; 331 enum netkit_action default_peer = NETKIT_PASS; 332 enum netkit_mode mode = NETKIT_L3; 333 unsigned char ifname_assign_type; 334 struct ifinfomsg *ifmp = NULL; 335 struct net_device *peer; 336 char ifname[IFNAMSIZ]; 337 struct netkit *nk; 338 struct net *net; 339 int err; 340 341 if (data) { 342 if (data[IFLA_NETKIT_MODE]) { 343 attr = data[IFLA_NETKIT_MODE]; 344 mode = nla_get_u32(attr); 345 err = netkit_check_mode(mode, attr, extack); 346 if (err < 0) 347 return err; 348 } 349 if (data[IFLA_NETKIT_PEER_INFO]) { 350 attr = data[IFLA_NETKIT_PEER_INFO]; 351 ifmp = nla_data(attr); 352 err = rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack); 353 if (err < 0) 354 return err; 355 err = netkit_validate(peer_tb, NULL, extack); 356 if (err < 0) 357 return err; 358 tbp = peer_tb; 359 } 360 if (data[IFLA_NETKIT_POLICY]) { 361 attr = data[IFLA_NETKIT_POLICY]; 362 default_prim = nla_get_u32(attr); 363 err = netkit_check_policy(default_prim, attr, extack); 364 if (err < 0) 365 return err; 366 } 367 if (data[IFLA_NETKIT_PEER_POLICY]) { 368 attr = data[IFLA_NETKIT_PEER_POLICY]; 369 default_peer = nla_get_u32(attr); 370 err = netkit_check_policy(default_peer, attr, extack); 371 if (err < 0) 372 return err; 373 } 374 } 375 376 if (ifmp && tbp[IFLA_IFNAME]) { 377 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ); 378 ifname_assign_type = NET_NAME_USER; 379 } else { 380 strscpy(ifname, "nk%d", IFNAMSIZ); 381 ifname_assign_type = NET_NAME_ENUM; 382 } 383 if (mode != NETKIT_L2 && 384 (tb[IFLA_ADDRESS] || tbp[IFLA_ADDRESS])) 385 return -EOPNOTSUPP; 386 387 net = rtnl_link_get_net(src_net, tbp); 388 if (IS_ERR(net)) 389 return PTR_ERR(net); 390 391 peer = rtnl_create_link(net, ifname, ifname_assign_type, 392 &netkit_link_ops, tbp, extack); 393 if (IS_ERR(peer)) { 394 put_net(net); 395 return PTR_ERR(peer); 396 } 397 398 netif_inherit_tso_max(peer, dev); 399 400 if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS])) 401 eth_hw_addr_random(peer); 402 if (ifmp && dev->ifindex) 403 peer->ifindex = ifmp->ifi_index; 404 405 nk = netkit_priv(peer); 406 nk->primary = false; 407 nk->policy = default_peer; 408 nk->mode = mode; 409 bpf_mprog_bundle_init(&nk->bundle); 410 411 err = register_netdevice(peer); 412 put_net(net); 413 if (err < 0) 414 goto err_register_peer; 415 netif_carrier_off(peer); 416 if (mode == NETKIT_L2) 417 dev_change_flags(peer, peer->flags & ~IFF_NOARP, NULL); 418 419 err = rtnl_configure_link(peer, NULL, 0, NULL); 420 if (err < 0) 421 goto err_configure_peer; 422 423 if (mode == NETKIT_L2 && !tb[IFLA_ADDRESS]) 424 eth_hw_addr_random(dev); 425 if (tb[IFLA_IFNAME]) 426 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ); 427 else 428 strscpy(dev->name, "nk%d", IFNAMSIZ); 429 430 nk = netkit_priv(dev); 431 nk->primary = true; 432 nk->policy = default_prim; 433 nk->mode = mode; 434 bpf_mprog_bundle_init(&nk->bundle); 435 436 err = register_netdevice(dev); 437 if (err < 0) 438 goto err_configure_peer; 439 netif_carrier_off(dev); 440 if (mode == NETKIT_L2) 441 dev_change_flags(dev, dev->flags & ~IFF_NOARP, NULL); 442 443 rcu_assign_pointer(netkit_priv(dev)->peer, peer); 444 rcu_assign_pointer(netkit_priv(peer)->peer, dev); 445 return 0; 446 err_configure_peer: 447 unregister_netdevice(peer); 448 return err; 449 err_register_peer: 450 free_netdev(peer); 451 return err; 452 } 453 454 static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev, 455 bool bundle_fallback) 456 { 457 struct netkit *nk = netkit_priv(dev); 458 struct bpf_mprog_entry *entry; 459 460 ASSERT_RTNL(); 461 entry = rcu_dereference_rtnl(nk->active); 462 if (entry) 463 return entry; 464 if (bundle_fallback) 465 return &nk->bundle.a; 466 return NULL; 467 } 468 469 static void netkit_entry_update(struct net_device *dev, 470 struct bpf_mprog_entry *entry) 471 { 472 struct netkit *nk = netkit_priv(dev); 473 474 ASSERT_RTNL(); 475 rcu_assign_pointer(nk->active, entry); 476 } 477 478 static void netkit_entry_sync(void) 479 { 480 synchronize_rcu(); 481 } 482 483 static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which) 484 { 485 struct net_device *dev; 486 struct netkit *nk; 487 488 ASSERT_RTNL(); 489 490 switch (which) { 491 case BPF_NETKIT_PRIMARY: 492 case BPF_NETKIT_PEER: 493 break; 494 default: 495 return ERR_PTR(-EINVAL); 496 } 497 498 dev = __dev_get_by_index(net, ifindex); 499 if (!dev) 500 return ERR_PTR(-ENODEV); 501 if (dev->netdev_ops != &netkit_netdev_ops) 502 return ERR_PTR(-ENXIO); 503 504 nk = netkit_priv(dev); 505 if (!nk->primary) 506 return ERR_PTR(-EACCES); 507 if (which == BPF_NETKIT_PEER) { 508 dev = rcu_dereference_rtnl(nk->peer); 509 if (!dev) 510 return ERR_PTR(-ENODEV); 511 } 512 return dev; 513 } 514 515 int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 516 { 517 struct bpf_mprog_entry *entry, *entry_new; 518 struct bpf_prog *replace_prog = NULL; 519 struct net_device *dev; 520 int ret; 521 522 rtnl_lock(); 523 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 524 attr->attach_type); 525 if (IS_ERR(dev)) { 526 ret = PTR_ERR(dev); 527 goto out; 528 } 529 entry = netkit_entry_fetch(dev, true); 530 if (attr->attach_flags & BPF_F_REPLACE) { 531 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, 532 prog->type); 533 if (IS_ERR(replace_prog)) { 534 ret = PTR_ERR(replace_prog); 535 replace_prog = NULL; 536 goto out; 537 } 538 } 539 ret = bpf_mprog_attach(entry, &entry_new, prog, NULL, replace_prog, 540 attr->attach_flags, attr->relative_fd, 541 attr->expected_revision); 542 if (!ret) { 543 if (entry != entry_new) { 544 netkit_entry_update(dev, entry_new); 545 netkit_entry_sync(); 546 } 547 bpf_mprog_commit(entry); 548 } 549 out: 550 if (replace_prog) 551 bpf_prog_put(replace_prog); 552 rtnl_unlock(); 553 return ret; 554 } 555 556 int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog) 557 { 558 struct bpf_mprog_entry *entry, *entry_new; 559 struct net_device *dev; 560 int ret; 561 562 rtnl_lock(); 563 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 564 attr->attach_type); 565 if (IS_ERR(dev)) { 566 ret = PTR_ERR(dev); 567 goto out; 568 } 569 entry = netkit_entry_fetch(dev, false); 570 if (!entry) { 571 ret = -ENOENT; 572 goto out; 573 } 574 ret = bpf_mprog_detach(entry, &entry_new, prog, NULL, attr->attach_flags, 575 attr->relative_fd, attr->expected_revision); 576 if (!ret) { 577 if (!bpf_mprog_total(entry_new)) 578 entry_new = NULL; 579 netkit_entry_update(dev, entry_new); 580 netkit_entry_sync(); 581 bpf_mprog_commit(entry); 582 } 583 out: 584 rtnl_unlock(); 585 return ret; 586 } 587 588 int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 589 { 590 struct net_device *dev; 591 int ret; 592 593 rtnl_lock(); 594 dev = netkit_dev_fetch(current->nsproxy->net_ns, 595 attr->query.target_ifindex, 596 attr->query.attach_type); 597 if (IS_ERR(dev)) { 598 ret = PTR_ERR(dev); 599 goto out; 600 } 601 ret = bpf_mprog_query(attr, uattr, netkit_entry_fetch(dev, false)); 602 out: 603 rtnl_unlock(); 604 return ret; 605 } 606 607 static struct netkit_link *netkit_link(const struct bpf_link *link) 608 { 609 return container_of(link, struct netkit_link, link); 610 } 611 612 static int netkit_link_prog_attach(struct bpf_link *link, u32 flags, 613 u32 id_or_fd, u64 revision) 614 { 615 struct netkit_link *nkl = netkit_link(link); 616 struct bpf_mprog_entry *entry, *entry_new; 617 struct net_device *dev = nkl->dev; 618 int ret; 619 620 ASSERT_RTNL(); 621 entry = netkit_entry_fetch(dev, true); 622 ret = bpf_mprog_attach(entry, &entry_new, link->prog, link, NULL, flags, 623 id_or_fd, revision); 624 if (!ret) { 625 if (entry != entry_new) { 626 netkit_entry_update(dev, entry_new); 627 netkit_entry_sync(); 628 } 629 bpf_mprog_commit(entry); 630 } 631 return ret; 632 } 633 634 static void netkit_link_release(struct bpf_link *link) 635 { 636 struct netkit_link *nkl = netkit_link(link); 637 struct bpf_mprog_entry *entry, *entry_new; 638 struct net_device *dev; 639 int ret = 0; 640 641 rtnl_lock(); 642 dev = nkl->dev; 643 if (!dev) 644 goto out; 645 entry = netkit_entry_fetch(dev, false); 646 if (!entry) { 647 ret = -ENOENT; 648 goto out; 649 } 650 ret = bpf_mprog_detach(entry, &entry_new, link->prog, link, 0, 0, 0); 651 if (!ret) { 652 if (!bpf_mprog_total(entry_new)) 653 entry_new = NULL; 654 netkit_entry_update(dev, entry_new); 655 netkit_entry_sync(); 656 bpf_mprog_commit(entry); 657 nkl->dev = NULL; 658 } 659 out: 660 WARN_ON_ONCE(ret); 661 rtnl_unlock(); 662 } 663 664 static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog, 665 struct bpf_prog *oprog) 666 { 667 struct netkit_link *nkl = netkit_link(link); 668 struct bpf_mprog_entry *entry, *entry_new; 669 struct net_device *dev; 670 int ret = 0; 671 672 rtnl_lock(); 673 dev = nkl->dev; 674 if (!dev) { 675 ret = -ENOLINK; 676 goto out; 677 } 678 if (oprog && link->prog != oprog) { 679 ret = -EPERM; 680 goto out; 681 } 682 oprog = link->prog; 683 if (oprog == nprog) { 684 bpf_prog_put(nprog); 685 goto out; 686 } 687 entry = netkit_entry_fetch(dev, false); 688 if (!entry) { 689 ret = -ENOENT; 690 goto out; 691 } 692 ret = bpf_mprog_attach(entry, &entry_new, nprog, link, oprog, 693 BPF_F_REPLACE | BPF_F_ID, 694 link->prog->aux->id, 0); 695 if (!ret) { 696 WARN_ON_ONCE(entry != entry_new); 697 oprog = xchg(&link->prog, nprog); 698 bpf_prog_put(oprog); 699 bpf_mprog_commit(entry); 700 } 701 out: 702 rtnl_unlock(); 703 return ret; 704 } 705 706 static void netkit_link_dealloc(struct bpf_link *link) 707 { 708 kfree(netkit_link(link)); 709 } 710 711 static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq) 712 { 713 const struct netkit_link *nkl = netkit_link(link); 714 u32 ifindex = 0; 715 716 rtnl_lock(); 717 if (nkl->dev) 718 ifindex = nkl->dev->ifindex; 719 rtnl_unlock(); 720 721 seq_printf(seq, "ifindex:\t%u\n", ifindex); 722 seq_printf(seq, "attach_type:\t%u (%s)\n", 723 nkl->location, 724 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer"); 725 } 726 727 static int netkit_link_fill_info(const struct bpf_link *link, 728 struct bpf_link_info *info) 729 { 730 const struct netkit_link *nkl = netkit_link(link); 731 u32 ifindex = 0; 732 733 rtnl_lock(); 734 if (nkl->dev) 735 ifindex = nkl->dev->ifindex; 736 rtnl_unlock(); 737 738 info->netkit.ifindex = ifindex; 739 info->netkit.attach_type = nkl->location; 740 return 0; 741 } 742 743 static int netkit_link_detach(struct bpf_link *link) 744 { 745 netkit_link_release(link); 746 return 0; 747 } 748 749 static const struct bpf_link_ops netkit_link_lops = { 750 .release = netkit_link_release, 751 .detach = netkit_link_detach, 752 .dealloc = netkit_link_dealloc, 753 .update_prog = netkit_link_update, 754 .show_fdinfo = netkit_link_fdinfo, 755 .fill_link_info = netkit_link_fill_info, 756 }; 757 758 static int netkit_link_init(struct netkit_link *nkl, 759 struct bpf_link_primer *link_primer, 760 const union bpf_attr *attr, 761 struct net_device *dev, 762 struct bpf_prog *prog) 763 { 764 bpf_link_init(&nkl->link, BPF_LINK_TYPE_NETKIT, 765 &netkit_link_lops, prog); 766 nkl->location = attr->link_create.attach_type; 767 nkl->dev = dev; 768 return bpf_link_prime(&nkl->link, link_primer); 769 } 770 771 int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 772 { 773 struct bpf_link_primer link_primer; 774 struct netkit_link *nkl; 775 struct net_device *dev; 776 int ret; 777 778 rtnl_lock(); 779 dev = netkit_dev_fetch(current->nsproxy->net_ns, 780 attr->link_create.target_ifindex, 781 attr->link_create.attach_type); 782 if (IS_ERR(dev)) { 783 ret = PTR_ERR(dev); 784 goto out; 785 } 786 nkl = kzalloc(sizeof(*nkl), GFP_KERNEL_ACCOUNT); 787 if (!nkl) { 788 ret = -ENOMEM; 789 goto out; 790 } 791 ret = netkit_link_init(nkl, &link_primer, attr, dev, prog); 792 if (ret) { 793 kfree(nkl); 794 goto out; 795 } 796 ret = netkit_link_prog_attach(&nkl->link, 797 attr->link_create.flags, 798 attr->link_create.netkit.relative_fd, 799 attr->link_create.netkit.expected_revision); 800 if (ret) { 801 nkl->dev = NULL; 802 bpf_link_cleanup(&link_primer); 803 goto out; 804 } 805 ret = bpf_link_settle(&link_primer); 806 out: 807 rtnl_unlock(); 808 return ret; 809 } 810 811 static void netkit_release_all(struct net_device *dev) 812 { 813 struct bpf_mprog_entry *entry; 814 struct bpf_tuple tuple = {}; 815 struct bpf_mprog_fp *fp; 816 struct bpf_mprog_cp *cp; 817 818 entry = netkit_entry_fetch(dev, false); 819 if (!entry) 820 return; 821 netkit_entry_update(dev, NULL); 822 netkit_entry_sync(); 823 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) { 824 if (tuple.link) 825 netkit_link(tuple.link)->dev = NULL; 826 else 827 bpf_prog_put(tuple.prog); 828 } 829 } 830 831 static void netkit_uninit(struct net_device *dev) 832 { 833 netkit_release_all(dev); 834 } 835 836 static void netkit_del_link(struct net_device *dev, struct list_head *head) 837 { 838 struct netkit *nk = netkit_priv(dev); 839 struct net_device *peer = rtnl_dereference(nk->peer); 840 841 RCU_INIT_POINTER(nk->peer, NULL); 842 unregister_netdevice_queue(dev, head); 843 if (peer) { 844 nk = netkit_priv(peer); 845 RCU_INIT_POINTER(nk->peer, NULL); 846 unregister_netdevice_queue(peer, head); 847 } 848 } 849 850 static int netkit_change_link(struct net_device *dev, struct nlattr *tb[], 851 struct nlattr *data[], 852 struct netlink_ext_ack *extack) 853 { 854 struct netkit *nk = netkit_priv(dev); 855 struct net_device *peer = rtnl_dereference(nk->peer); 856 enum netkit_action policy; 857 struct nlattr *attr; 858 int err; 859 860 if (!nk->primary) { 861 NL_SET_ERR_MSG(extack, 862 "netkit link settings can be changed only through the primary device"); 863 return -EACCES; 864 } 865 866 if (data[IFLA_NETKIT_MODE]) { 867 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE], 868 "netkit link operating mode cannot be changed after device creation"); 869 return -EACCES; 870 } 871 872 if (data[IFLA_NETKIT_PEER_INFO]) { 873 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO], 874 "netkit peer info cannot be changed after device creation"); 875 return -EINVAL; 876 } 877 878 if (data[IFLA_NETKIT_POLICY]) { 879 attr = data[IFLA_NETKIT_POLICY]; 880 policy = nla_get_u32(attr); 881 err = netkit_check_policy(policy, attr, extack); 882 if (err) 883 return err; 884 WRITE_ONCE(nk->policy, policy); 885 } 886 887 if (data[IFLA_NETKIT_PEER_POLICY]) { 888 err = -EOPNOTSUPP; 889 attr = data[IFLA_NETKIT_PEER_POLICY]; 890 policy = nla_get_u32(attr); 891 if (peer) 892 err = netkit_check_policy(policy, attr, extack); 893 if (err) 894 return err; 895 nk = netkit_priv(peer); 896 WRITE_ONCE(nk->policy, policy); 897 } 898 899 return 0; 900 } 901 902 static size_t netkit_get_size(const struct net_device *dev) 903 { 904 return nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_POLICY */ 905 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */ 906 nla_total_size(sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */ 907 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */ 908 0; 909 } 910 911 static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev) 912 { 913 struct netkit *nk = netkit_priv(dev); 914 struct net_device *peer = rtnl_dereference(nk->peer); 915 916 if (nla_put_u8(skb, IFLA_NETKIT_PRIMARY, nk->primary)) 917 return -EMSGSIZE; 918 if (nla_put_u32(skb, IFLA_NETKIT_POLICY, nk->policy)) 919 return -EMSGSIZE; 920 if (nla_put_u32(skb, IFLA_NETKIT_MODE, nk->mode)) 921 return -EMSGSIZE; 922 923 if (peer) { 924 nk = netkit_priv(peer); 925 if (nla_put_u32(skb, IFLA_NETKIT_PEER_POLICY, nk->policy)) 926 return -EMSGSIZE; 927 } 928 929 return 0; 930 } 931 932 static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = { 933 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) }, 934 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 }, 935 [IFLA_NETKIT_MODE] = { .type = NLA_U32 }, 936 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 }, 937 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT, 938 .reject_message = "Primary attribute is read-only" }, 939 }; 940 941 static struct rtnl_link_ops netkit_link_ops = { 942 .kind = DRV_NAME, 943 .priv_size = sizeof(struct netkit), 944 .setup = netkit_setup, 945 .newlink = netkit_new_link, 946 .dellink = netkit_del_link, 947 .changelink = netkit_change_link, 948 .get_link_net = netkit_get_link_net, 949 .get_size = netkit_get_size, 950 .fill_info = netkit_fill_info, 951 .policy = netkit_policy, 952 .validate = netkit_validate, 953 .maxtype = IFLA_NETKIT_MAX, 954 }; 955 956 static __init int netkit_init(void) 957 { 958 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT || 959 (int)NETKIT_PASS != (int)TCX_PASS || 960 (int)NETKIT_DROP != (int)TCX_DROP || 961 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT); 962 963 return rtnl_link_register(&netkit_link_ops); 964 } 965 966 static __exit void netkit_exit(void) 967 { 968 rtnl_link_unregister(&netkit_link_ops); 969 } 970 971 module_init(netkit_init); 972 module_exit(netkit_exit); 973 974 MODULE_DESCRIPTION("BPF-programmable network device"); 975 MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>"); 976 MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>"); 977 MODULE_LICENSE("GPL"); 978 MODULE_ALIAS_RTNL_LINK(DRV_NAME); 979