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