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 enum netkit_scrub scrub; 24 struct bpf_mprog_bundle bundle; 25 26 /* Needed in slow-path */ 27 enum netkit_mode mode; 28 bool primary; 29 u32 headroom; 30 }; 31 32 struct netkit_link { 33 struct bpf_link link; 34 struct net_device *dev; 35 u32 location; 36 }; 37 38 static __always_inline int 39 netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb, 40 enum netkit_action ret) 41 { 42 const struct bpf_mprog_fp *fp; 43 const struct bpf_prog *prog; 44 45 bpf_mprog_foreach_prog(entry, fp, prog) { 46 bpf_compute_data_pointers(skb); 47 ret = bpf_prog_run(prog, skb); 48 if (ret != NETKIT_NEXT) 49 break; 50 } 51 return ret; 52 } 53 54 static void netkit_xnet(struct sk_buff *skb) 55 { 56 skb->priority = 0; 57 skb->mark = 0; 58 } 59 60 static void netkit_prep_forward(struct sk_buff *skb, 61 bool xnet, bool xnet_scrub) 62 { 63 skb_scrub_packet(skb, false); 64 nf_skip_egress(skb, true); 65 skb_reset_mac_header(skb); 66 if (!xnet) 67 return; 68 ipvs_reset(skb); 69 skb_clear_tstamp(skb); 70 if (xnet_scrub) 71 netkit_xnet(skb); 72 } 73 74 static struct netkit *netkit_priv(const struct net_device *dev) 75 { 76 return netdev_priv(dev); 77 } 78 79 static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev) 80 { 81 struct bpf_net_context __bpf_net_ctx, *bpf_net_ctx; 82 struct netkit *nk = netkit_priv(dev); 83 enum netkit_action ret = READ_ONCE(nk->policy); 84 netdev_tx_t ret_dev = NET_XMIT_SUCCESS; 85 const struct bpf_mprog_entry *entry; 86 struct net_device *peer; 87 int len = skb->len; 88 89 bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx); 90 rcu_read_lock(); 91 peer = rcu_dereference(nk->peer); 92 if (unlikely(!peer || !(peer->flags & IFF_UP) || 93 !pskb_may_pull(skb, ETH_HLEN) || 94 skb_orphan_frags(skb, GFP_ATOMIC))) 95 goto drop; 96 netkit_prep_forward(skb, !net_eq(dev_net(dev), dev_net(peer)), 97 nk->scrub); 98 eth_skb_pkt_type(skb, peer); 99 skb->dev = peer; 100 entry = rcu_dereference(nk->active); 101 if (entry) 102 ret = netkit_run(entry, skb, ret); 103 switch (ret) { 104 case NETKIT_NEXT: 105 case NETKIT_PASS: 106 eth_skb_pull_mac(skb); 107 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); 108 if (likely(__netif_rx(skb) == NET_RX_SUCCESS)) { 109 dev_sw_netstats_tx_add(dev, 1, len); 110 dev_sw_netstats_rx_add(peer, len); 111 } else { 112 goto drop_stats; 113 } 114 break; 115 case NETKIT_REDIRECT: 116 dev_sw_netstats_tx_add(dev, 1, len); 117 skb_do_redirect(skb); 118 break; 119 case NETKIT_DROP: 120 default: 121 drop: 122 kfree_skb(skb); 123 drop_stats: 124 dev_core_stats_tx_dropped_inc(dev); 125 ret_dev = NET_XMIT_DROP; 126 break; 127 } 128 rcu_read_unlock(); 129 bpf_net_ctx_clear(bpf_net_ctx); 130 return ret_dev; 131 } 132 133 static int netkit_open(struct net_device *dev) 134 { 135 struct netkit *nk = netkit_priv(dev); 136 struct net_device *peer = rtnl_dereference(nk->peer); 137 138 if (!peer) 139 return -ENOTCONN; 140 if (peer->flags & IFF_UP) { 141 netif_carrier_on(dev); 142 netif_carrier_on(peer); 143 } 144 return 0; 145 } 146 147 static int netkit_close(struct net_device *dev) 148 { 149 struct netkit *nk = netkit_priv(dev); 150 struct net_device *peer = rtnl_dereference(nk->peer); 151 152 netif_carrier_off(dev); 153 if (peer) 154 netif_carrier_off(peer); 155 return 0; 156 } 157 158 static int netkit_get_iflink(const struct net_device *dev) 159 { 160 struct netkit *nk = netkit_priv(dev); 161 struct net_device *peer; 162 int iflink = 0; 163 164 rcu_read_lock(); 165 peer = rcu_dereference(nk->peer); 166 if (peer) 167 iflink = READ_ONCE(peer->ifindex); 168 rcu_read_unlock(); 169 return iflink; 170 } 171 172 static void netkit_set_multicast(struct net_device *dev) 173 { 174 /* Nothing to do, we receive whatever gets pushed to us! */ 175 } 176 177 static int netkit_set_macaddr(struct net_device *dev, void *sa) 178 { 179 struct netkit *nk = netkit_priv(dev); 180 181 if (nk->mode != NETKIT_L2) 182 return -EOPNOTSUPP; 183 184 return eth_mac_addr(dev, sa); 185 } 186 187 static void netkit_set_headroom(struct net_device *dev, int headroom) 188 { 189 struct netkit *nk = netkit_priv(dev), *nk2; 190 struct net_device *peer; 191 192 if (headroom < 0) 193 headroom = NET_SKB_PAD; 194 195 rcu_read_lock(); 196 peer = rcu_dereference(nk->peer); 197 if (unlikely(!peer)) 198 goto out; 199 200 nk2 = netkit_priv(peer); 201 nk->headroom = headroom; 202 headroom = max(nk->headroom, nk2->headroom); 203 204 peer->needed_headroom = headroom; 205 dev->needed_headroom = headroom; 206 out: 207 rcu_read_unlock(); 208 } 209 210 INDIRECT_CALLABLE_SCOPE struct net_device *netkit_peer_dev(struct net_device *dev) 211 { 212 return rcu_dereference(netkit_priv(dev)->peer); 213 } 214 215 static void netkit_get_stats(struct net_device *dev, 216 struct rtnl_link_stats64 *stats) 217 { 218 dev_fetch_sw_netstats(stats, dev->tstats); 219 stats->tx_dropped = DEV_STATS_READ(dev, tx_dropped); 220 } 221 222 static void netkit_uninit(struct net_device *dev); 223 224 static const struct net_device_ops netkit_netdev_ops = { 225 .ndo_open = netkit_open, 226 .ndo_stop = netkit_close, 227 .ndo_start_xmit = netkit_xmit, 228 .ndo_set_rx_mode = netkit_set_multicast, 229 .ndo_set_rx_headroom = netkit_set_headroom, 230 .ndo_set_mac_address = netkit_set_macaddr, 231 .ndo_get_iflink = netkit_get_iflink, 232 .ndo_get_peer_dev = netkit_peer_dev, 233 .ndo_get_stats64 = netkit_get_stats, 234 .ndo_uninit = netkit_uninit, 235 .ndo_features_check = passthru_features_check, 236 }; 237 238 static void netkit_get_drvinfo(struct net_device *dev, 239 struct ethtool_drvinfo *info) 240 { 241 strscpy(info->driver, DRV_NAME, sizeof(info->driver)); 242 } 243 244 static const struct ethtool_ops netkit_ethtool_ops = { 245 .get_drvinfo = netkit_get_drvinfo, 246 }; 247 248 static void netkit_setup(struct net_device *dev) 249 { 250 static const netdev_features_t netkit_features_hw_vlan = 251 NETIF_F_HW_VLAN_CTAG_TX | 252 NETIF_F_HW_VLAN_CTAG_RX | 253 NETIF_F_HW_VLAN_STAG_TX | 254 NETIF_F_HW_VLAN_STAG_RX; 255 static const netdev_features_t netkit_features = 256 netkit_features_hw_vlan | 257 NETIF_F_SG | 258 NETIF_F_FRAGLIST | 259 NETIF_F_HW_CSUM | 260 NETIF_F_RXCSUM | 261 NETIF_F_SCTP_CRC | 262 NETIF_F_HIGHDMA | 263 NETIF_F_GSO_SOFTWARE | 264 NETIF_F_GSO_ENCAP_ALL; 265 266 ether_setup(dev); 267 dev->max_mtu = ETH_MAX_MTU; 268 dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS; 269 270 dev->flags |= IFF_NOARP; 271 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 272 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 273 dev->priv_flags |= IFF_PHONY_HEADROOM; 274 dev->priv_flags |= IFF_NO_QUEUE; 275 dev->priv_flags |= IFF_DISABLE_NETPOLL; 276 dev->lltx = true; 277 278 dev->ethtool_ops = &netkit_ethtool_ops; 279 dev->netdev_ops = &netkit_netdev_ops; 280 281 dev->features |= netkit_features; 282 dev->hw_features = netkit_features; 283 dev->hw_enc_features = netkit_features; 284 dev->mpls_features = NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE; 285 dev->vlan_features = dev->features & ~netkit_features_hw_vlan; 286 287 dev->needs_free_netdev = true; 288 289 netif_set_tso_max_size(dev, GSO_MAX_SIZE); 290 } 291 292 static struct net *netkit_get_link_net(const struct net_device *dev) 293 { 294 struct netkit *nk = netkit_priv(dev); 295 struct net_device *peer = rtnl_dereference(nk->peer); 296 297 return peer ? dev_net(peer) : dev_net(dev); 298 } 299 300 static int netkit_check_policy(int policy, struct nlattr *tb, 301 struct netlink_ext_ack *extack) 302 { 303 switch (policy) { 304 case NETKIT_PASS: 305 case NETKIT_DROP: 306 return 0; 307 default: 308 NL_SET_ERR_MSG_ATTR(extack, tb, 309 "Provided default xmit policy not supported"); 310 return -EINVAL; 311 } 312 } 313 314 static int netkit_validate(struct nlattr *tb[], struct nlattr *data[], 315 struct netlink_ext_ack *extack) 316 { 317 struct nlattr *attr = tb[IFLA_ADDRESS]; 318 319 if (!attr) 320 return 0; 321 if (nla_len(attr) != ETH_ALEN) 322 return -EINVAL; 323 if (!is_valid_ether_addr(nla_data(attr))) 324 return -EADDRNOTAVAIL; 325 return 0; 326 } 327 328 static struct rtnl_link_ops netkit_link_ops; 329 330 static int netkit_new_link(struct net *src_net, struct net_device *dev, 331 struct nlattr *tb[], struct nlattr *data[], 332 struct netlink_ext_ack *extack) 333 { 334 struct nlattr *peer_tb[IFLA_MAX + 1], **tbp = tb, *attr; 335 enum netkit_action policy_prim = NETKIT_PASS; 336 enum netkit_action policy_peer = NETKIT_PASS; 337 enum netkit_scrub scrub_prim = NETKIT_SCRUB_DEFAULT; 338 enum netkit_scrub scrub_peer = NETKIT_SCRUB_DEFAULT; 339 enum netkit_mode mode = NETKIT_L3; 340 unsigned char ifname_assign_type; 341 struct ifinfomsg *ifmp = NULL; 342 struct net_device *peer; 343 char ifname[IFNAMSIZ]; 344 struct netkit *nk; 345 struct net *net; 346 int err; 347 348 if (data) { 349 if (data[IFLA_NETKIT_MODE]) 350 mode = nla_get_u32(data[IFLA_NETKIT_MODE]); 351 if (data[IFLA_NETKIT_PEER_INFO]) { 352 attr = data[IFLA_NETKIT_PEER_INFO]; 353 ifmp = nla_data(attr); 354 err = rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack); 355 if (err < 0) 356 return err; 357 err = netkit_validate(peer_tb, NULL, extack); 358 if (err < 0) 359 return err; 360 tbp = peer_tb; 361 } 362 if (data[IFLA_NETKIT_SCRUB]) 363 scrub_prim = nla_get_u32(data[IFLA_NETKIT_SCRUB]); 364 if (data[IFLA_NETKIT_PEER_SCRUB]) 365 scrub_peer = nla_get_u32(data[IFLA_NETKIT_PEER_SCRUB]); 366 if (data[IFLA_NETKIT_POLICY]) { 367 attr = data[IFLA_NETKIT_POLICY]; 368 policy_prim = nla_get_u32(attr); 369 err = netkit_check_policy(policy_prim, attr, extack); 370 if (err < 0) 371 return err; 372 } 373 if (data[IFLA_NETKIT_PEER_POLICY]) { 374 attr = data[IFLA_NETKIT_PEER_POLICY]; 375 policy_peer = nla_get_u32(attr); 376 err = netkit_check_policy(policy_peer, attr, extack); 377 if (err < 0) 378 return err; 379 } 380 } 381 382 if (ifmp && tbp[IFLA_IFNAME]) { 383 nla_strscpy(ifname, tbp[IFLA_IFNAME], IFNAMSIZ); 384 ifname_assign_type = NET_NAME_USER; 385 } else { 386 strscpy(ifname, "nk%d", IFNAMSIZ); 387 ifname_assign_type = NET_NAME_ENUM; 388 } 389 if (mode != NETKIT_L2 && 390 (tb[IFLA_ADDRESS] || tbp[IFLA_ADDRESS])) 391 return -EOPNOTSUPP; 392 393 net = rtnl_link_get_net(src_net, tbp); 394 if (IS_ERR(net)) 395 return PTR_ERR(net); 396 397 peer = rtnl_create_link(net, ifname, ifname_assign_type, 398 &netkit_link_ops, tbp, extack); 399 if (IS_ERR(peer)) { 400 put_net(net); 401 return PTR_ERR(peer); 402 } 403 404 netif_inherit_tso_max(peer, dev); 405 406 if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS])) 407 eth_hw_addr_random(peer); 408 if (ifmp && dev->ifindex) 409 peer->ifindex = ifmp->ifi_index; 410 411 nk = netkit_priv(peer); 412 nk->primary = false; 413 nk->policy = policy_peer; 414 nk->scrub = scrub_peer; 415 nk->mode = mode; 416 bpf_mprog_bundle_init(&nk->bundle); 417 418 err = register_netdevice(peer); 419 put_net(net); 420 if (err < 0) 421 goto err_register_peer; 422 netif_carrier_off(peer); 423 if (mode == NETKIT_L2) 424 dev_change_flags(peer, peer->flags & ~IFF_NOARP, NULL); 425 426 err = rtnl_configure_link(peer, NULL, 0, NULL); 427 if (err < 0) 428 goto err_configure_peer; 429 430 if (mode == NETKIT_L2 && !tb[IFLA_ADDRESS]) 431 eth_hw_addr_random(dev); 432 if (tb[IFLA_IFNAME]) 433 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ); 434 else 435 strscpy(dev->name, "nk%d", IFNAMSIZ); 436 437 nk = netkit_priv(dev); 438 nk->primary = true; 439 nk->policy = policy_prim; 440 nk->scrub = scrub_prim; 441 nk->mode = mode; 442 bpf_mprog_bundle_init(&nk->bundle); 443 444 err = register_netdevice(dev); 445 if (err < 0) 446 goto err_configure_peer; 447 netif_carrier_off(dev); 448 if (mode == NETKIT_L2) 449 dev_change_flags(dev, dev->flags & ~IFF_NOARP, NULL); 450 451 rcu_assign_pointer(netkit_priv(dev)->peer, peer); 452 rcu_assign_pointer(netkit_priv(peer)->peer, dev); 453 return 0; 454 err_configure_peer: 455 unregister_netdevice(peer); 456 return err; 457 err_register_peer: 458 free_netdev(peer); 459 return err; 460 } 461 462 static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev, 463 bool bundle_fallback) 464 { 465 struct netkit *nk = netkit_priv(dev); 466 struct bpf_mprog_entry *entry; 467 468 ASSERT_RTNL(); 469 entry = rcu_dereference_rtnl(nk->active); 470 if (entry) 471 return entry; 472 if (bundle_fallback) 473 return &nk->bundle.a; 474 return NULL; 475 } 476 477 static void netkit_entry_update(struct net_device *dev, 478 struct bpf_mprog_entry *entry) 479 { 480 struct netkit *nk = netkit_priv(dev); 481 482 ASSERT_RTNL(); 483 rcu_assign_pointer(nk->active, entry); 484 } 485 486 static void netkit_entry_sync(void) 487 { 488 synchronize_rcu(); 489 } 490 491 static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which) 492 { 493 struct net_device *dev; 494 struct netkit *nk; 495 496 ASSERT_RTNL(); 497 498 switch (which) { 499 case BPF_NETKIT_PRIMARY: 500 case BPF_NETKIT_PEER: 501 break; 502 default: 503 return ERR_PTR(-EINVAL); 504 } 505 506 dev = __dev_get_by_index(net, ifindex); 507 if (!dev) 508 return ERR_PTR(-ENODEV); 509 if (dev->netdev_ops != &netkit_netdev_ops) 510 return ERR_PTR(-ENXIO); 511 512 nk = netkit_priv(dev); 513 if (!nk->primary) 514 return ERR_PTR(-EACCES); 515 if (which == BPF_NETKIT_PEER) { 516 dev = rcu_dereference_rtnl(nk->peer); 517 if (!dev) 518 return ERR_PTR(-ENODEV); 519 } 520 return dev; 521 } 522 523 int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 524 { 525 struct bpf_mprog_entry *entry, *entry_new; 526 struct bpf_prog *replace_prog = NULL; 527 struct net_device *dev; 528 int ret; 529 530 rtnl_lock(); 531 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 532 attr->attach_type); 533 if (IS_ERR(dev)) { 534 ret = PTR_ERR(dev); 535 goto out; 536 } 537 entry = netkit_entry_fetch(dev, true); 538 if (attr->attach_flags & BPF_F_REPLACE) { 539 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, 540 prog->type); 541 if (IS_ERR(replace_prog)) { 542 ret = PTR_ERR(replace_prog); 543 replace_prog = NULL; 544 goto out; 545 } 546 } 547 ret = bpf_mprog_attach(entry, &entry_new, prog, NULL, replace_prog, 548 attr->attach_flags, attr->relative_fd, 549 attr->expected_revision); 550 if (!ret) { 551 if (entry != entry_new) { 552 netkit_entry_update(dev, entry_new); 553 netkit_entry_sync(); 554 } 555 bpf_mprog_commit(entry); 556 } 557 out: 558 if (replace_prog) 559 bpf_prog_put(replace_prog); 560 rtnl_unlock(); 561 return ret; 562 } 563 564 int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog) 565 { 566 struct bpf_mprog_entry *entry, *entry_new; 567 struct net_device *dev; 568 int ret; 569 570 rtnl_lock(); 571 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 572 attr->attach_type); 573 if (IS_ERR(dev)) { 574 ret = PTR_ERR(dev); 575 goto out; 576 } 577 entry = netkit_entry_fetch(dev, false); 578 if (!entry) { 579 ret = -ENOENT; 580 goto out; 581 } 582 ret = bpf_mprog_detach(entry, &entry_new, prog, NULL, attr->attach_flags, 583 attr->relative_fd, attr->expected_revision); 584 if (!ret) { 585 if (!bpf_mprog_total(entry_new)) 586 entry_new = NULL; 587 netkit_entry_update(dev, entry_new); 588 netkit_entry_sync(); 589 bpf_mprog_commit(entry); 590 } 591 out: 592 rtnl_unlock(); 593 return ret; 594 } 595 596 int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 597 { 598 struct net_device *dev; 599 int ret; 600 601 rtnl_lock(); 602 dev = netkit_dev_fetch(current->nsproxy->net_ns, 603 attr->query.target_ifindex, 604 attr->query.attach_type); 605 if (IS_ERR(dev)) { 606 ret = PTR_ERR(dev); 607 goto out; 608 } 609 ret = bpf_mprog_query(attr, uattr, netkit_entry_fetch(dev, false)); 610 out: 611 rtnl_unlock(); 612 return ret; 613 } 614 615 static struct netkit_link *netkit_link(const struct bpf_link *link) 616 { 617 return container_of(link, struct netkit_link, link); 618 } 619 620 static int netkit_link_prog_attach(struct bpf_link *link, u32 flags, 621 u32 id_or_fd, u64 revision) 622 { 623 struct netkit_link *nkl = netkit_link(link); 624 struct bpf_mprog_entry *entry, *entry_new; 625 struct net_device *dev = nkl->dev; 626 int ret; 627 628 ASSERT_RTNL(); 629 entry = netkit_entry_fetch(dev, true); 630 ret = bpf_mprog_attach(entry, &entry_new, link->prog, link, NULL, flags, 631 id_or_fd, revision); 632 if (!ret) { 633 if (entry != entry_new) { 634 netkit_entry_update(dev, entry_new); 635 netkit_entry_sync(); 636 } 637 bpf_mprog_commit(entry); 638 } 639 return ret; 640 } 641 642 static void netkit_link_release(struct bpf_link *link) 643 { 644 struct netkit_link *nkl = netkit_link(link); 645 struct bpf_mprog_entry *entry, *entry_new; 646 struct net_device *dev; 647 int ret = 0; 648 649 rtnl_lock(); 650 dev = nkl->dev; 651 if (!dev) 652 goto out; 653 entry = netkit_entry_fetch(dev, false); 654 if (!entry) { 655 ret = -ENOENT; 656 goto out; 657 } 658 ret = bpf_mprog_detach(entry, &entry_new, link->prog, link, 0, 0, 0); 659 if (!ret) { 660 if (!bpf_mprog_total(entry_new)) 661 entry_new = NULL; 662 netkit_entry_update(dev, entry_new); 663 netkit_entry_sync(); 664 bpf_mprog_commit(entry); 665 nkl->dev = NULL; 666 } 667 out: 668 WARN_ON_ONCE(ret); 669 rtnl_unlock(); 670 } 671 672 static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog, 673 struct bpf_prog *oprog) 674 { 675 struct netkit_link *nkl = netkit_link(link); 676 struct bpf_mprog_entry *entry, *entry_new; 677 struct net_device *dev; 678 int ret = 0; 679 680 rtnl_lock(); 681 dev = nkl->dev; 682 if (!dev) { 683 ret = -ENOLINK; 684 goto out; 685 } 686 if (oprog && link->prog != oprog) { 687 ret = -EPERM; 688 goto out; 689 } 690 oprog = link->prog; 691 if (oprog == nprog) { 692 bpf_prog_put(nprog); 693 goto out; 694 } 695 entry = netkit_entry_fetch(dev, false); 696 if (!entry) { 697 ret = -ENOENT; 698 goto out; 699 } 700 ret = bpf_mprog_attach(entry, &entry_new, nprog, link, oprog, 701 BPF_F_REPLACE | BPF_F_ID, 702 link->prog->aux->id, 0); 703 if (!ret) { 704 WARN_ON_ONCE(entry != entry_new); 705 oprog = xchg(&link->prog, nprog); 706 bpf_prog_put(oprog); 707 bpf_mprog_commit(entry); 708 } 709 out: 710 rtnl_unlock(); 711 return ret; 712 } 713 714 static void netkit_link_dealloc(struct bpf_link *link) 715 { 716 kfree(netkit_link(link)); 717 } 718 719 static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq) 720 { 721 const struct netkit_link *nkl = netkit_link(link); 722 u32 ifindex = 0; 723 724 rtnl_lock(); 725 if (nkl->dev) 726 ifindex = nkl->dev->ifindex; 727 rtnl_unlock(); 728 729 seq_printf(seq, "ifindex:\t%u\n", ifindex); 730 seq_printf(seq, "attach_type:\t%u (%s)\n", 731 nkl->location, 732 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer"); 733 } 734 735 static int netkit_link_fill_info(const struct bpf_link *link, 736 struct bpf_link_info *info) 737 { 738 const struct netkit_link *nkl = netkit_link(link); 739 u32 ifindex = 0; 740 741 rtnl_lock(); 742 if (nkl->dev) 743 ifindex = nkl->dev->ifindex; 744 rtnl_unlock(); 745 746 info->netkit.ifindex = ifindex; 747 info->netkit.attach_type = nkl->location; 748 return 0; 749 } 750 751 static int netkit_link_detach(struct bpf_link *link) 752 { 753 netkit_link_release(link); 754 return 0; 755 } 756 757 static const struct bpf_link_ops netkit_link_lops = { 758 .release = netkit_link_release, 759 .detach = netkit_link_detach, 760 .dealloc = netkit_link_dealloc, 761 .update_prog = netkit_link_update, 762 .show_fdinfo = netkit_link_fdinfo, 763 .fill_link_info = netkit_link_fill_info, 764 }; 765 766 static int netkit_link_init(struct netkit_link *nkl, 767 struct bpf_link_primer *link_primer, 768 const union bpf_attr *attr, 769 struct net_device *dev, 770 struct bpf_prog *prog) 771 { 772 bpf_link_init(&nkl->link, BPF_LINK_TYPE_NETKIT, 773 &netkit_link_lops, prog); 774 nkl->location = attr->link_create.attach_type; 775 nkl->dev = dev; 776 return bpf_link_prime(&nkl->link, link_primer); 777 } 778 779 int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 780 { 781 struct bpf_link_primer link_primer; 782 struct netkit_link *nkl; 783 struct net_device *dev; 784 int ret; 785 786 rtnl_lock(); 787 dev = netkit_dev_fetch(current->nsproxy->net_ns, 788 attr->link_create.target_ifindex, 789 attr->link_create.attach_type); 790 if (IS_ERR(dev)) { 791 ret = PTR_ERR(dev); 792 goto out; 793 } 794 nkl = kzalloc(sizeof(*nkl), GFP_KERNEL_ACCOUNT); 795 if (!nkl) { 796 ret = -ENOMEM; 797 goto out; 798 } 799 ret = netkit_link_init(nkl, &link_primer, attr, dev, prog); 800 if (ret) { 801 kfree(nkl); 802 goto out; 803 } 804 ret = netkit_link_prog_attach(&nkl->link, 805 attr->link_create.flags, 806 attr->link_create.netkit.relative_fd, 807 attr->link_create.netkit.expected_revision); 808 if (ret) { 809 nkl->dev = NULL; 810 bpf_link_cleanup(&link_primer); 811 goto out; 812 } 813 ret = bpf_link_settle(&link_primer); 814 out: 815 rtnl_unlock(); 816 return ret; 817 } 818 819 static void netkit_release_all(struct net_device *dev) 820 { 821 struct bpf_mprog_entry *entry; 822 struct bpf_tuple tuple = {}; 823 struct bpf_mprog_fp *fp; 824 struct bpf_mprog_cp *cp; 825 826 entry = netkit_entry_fetch(dev, false); 827 if (!entry) 828 return; 829 netkit_entry_update(dev, NULL); 830 netkit_entry_sync(); 831 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) { 832 if (tuple.link) 833 netkit_link(tuple.link)->dev = NULL; 834 else 835 bpf_prog_put(tuple.prog); 836 } 837 } 838 839 static void netkit_uninit(struct net_device *dev) 840 { 841 netkit_release_all(dev); 842 } 843 844 static void netkit_del_link(struct net_device *dev, struct list_head *head) 845 { 846 struct netkit *nk = netkit_priv(dev); 847 struct net_device *peer = rtnl_dereference(nk->peer); 848 849 RCU_INIT_POINTER(nk->peer, NULL); 850 unregister_netdevice_queue(dev, head); 851 if (peer) { 852 nk = netkit_priv(peer); 853 RCU_INIT_POINTER(nk->peer, NULL); 854 unregister_netdevice_queue(peer, head); 855 } 856 } 857 858 static int netkit_change_link(struct net_device *dev, struct nlattr *tb[], 859 struct nlattr *data[], 860 struct netlink_ext_ack *extack) 861 { 862 struct netkit *nk = netkit_priv(dev); 863 struct net_device *peer = rtnl_dereference(nk->peer); 864 enum netkit_action policy; 865 struct nlattr *attr; 866 int err; 867 868 if (!nk->primary) { 869 NL_SET_ERR_MSG(extack, 870 "netkit link settings can be changed only through the primary device"); 871 return -EACCES; 872 } 873 874 if (data[IFLA_NETKIT_MODE]) { 875 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE], 876 "netkit link operating mode cannot be changed after device creation"); 877 return -EACCES; 878 } 879 880 if (data[IFLA_NETKIT_SCRUB]) { 881 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_SCRUB], 882 "netkit scrubbing cannot be changed after device creation"); 883 return -EACCES; 884 } 885 886 if (data[IFLA_NETKIT_PEER_SCRUB]) { 887 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_SCRUB], 888 "netkit scrubbing cannot be changed after device creation"); 889 return -EACCES; 890 } 891 892 if (data[IFLA_NETKIT_PEER_INFO]) { 893 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO], 894 "netkit peer info cannot be changed after device creation"); 895 return -EINVAL; 896 } 897 898 if (data[IFLA_NETKIT_POLICY]) { 899 attr = data[IFLA_NETKIT_POLICY]; 900 policy = nla_get_u32(attr); 901 err = netkit_check_policy(policy, attr, extack); 902 if (err) 903 return err; 904 WRITE_ONCE(nk->policy, policy); 905 } 906 907 if (data[IFLA_NETKIT_PEER_POLICY]) { 908 err = -EOPNOTSUPP; 909 attr = data[IFLA_NETKIT_PEER_POLICY]; 910 policy = nla_get_u32(attr); 911 if (peer) 912 err = netkit_check_policy(policy, attr, extack); 913 if (err) 914 return err; 915 nk = netkit_priv(peer); 916 WRITE_ONCE(nk->policy, policy); 917 } 918 919 return 0; 920 } 921 922 static size_t netkit_get_size(const struct net_device *dev) 923 { 924 return nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_POLICY */ 925 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */ 926 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_SCRUB */ 927 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_SCRUB */ 928 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */ 929 nla_total_size(sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */ 930 0; 931 } 932 933 static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev) 934 { 935 struct netkit *nk = netkit_priv(dev); 936 struct net_device *peer = rtnl_dereference(nk->peer); 937 938 if (nla_put_u8(skb, IFLA_NETKIT_PRIMARY, nk->primary)) 939 return -EMSGSIZE; 940 if (nla_put_u32(skb, IFLA_NETKIT_POLICY, nk->policy)) 941 return -EMSGSIZE; 942 if (nla_put_u32(skb, IFLA_NETKIT_MODE, nk->mode)) 943 return -EMSGSIZE; 944 if (nla_put_u32(skb, IFLA_NETKIT_SCRUB, nk->scrub)) 945 return -EMSGSIZE; 946 947 if (peer) { 948 nk = netkit_priv(peer); 949 if (nla_put_u32(skb, IFLA_NETKIT_PEER_POLICY, nk->policy)) 950 return -EMSGSIZE; 951 if (nla_put_u32(skb, IFLA_NETKIT_PEER_SCRUB, nk->scrub)) 952 return -EMSGSIZE; 953 } 954 955 return 0; 956 } 957 958 static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = { 959 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) }, 960 [IFLA_NETKIT_MODE] = NLA_POLICY_MAX(NLA_U32, NETKIT_L3), 961 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 }, 962 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 }, 963 [IFLA_NETKIT_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT), 964 [IFLA_NETKIT_PEER_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT), 965 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT, 966 .reject_message = "Primary attribute is read-only" }, 967 }; 968 969 static struct rtnl_link_ops netkit_link_ops = { 970 .kind = DRV_NAME, 971 .priv_size = sizeof(struct netkit), 972 .setup = netkit_setup, 973 .newlink = netkit_new_link, 974 .dellink = netkit_del_link, 975 .changelink = netkit_change_link, 976 .get_link_net = netkit_get_link_net, 977 .get_size = netkit_get_size, 978 .fill_info = netkit_fill_info, 979 .policy = netkit_policy, 980 .validate = netkit_validate, 981 .maxtype = IFLA_NETKIT_MAX, 982 }; 983 984 static __init int netkit_init(void) 985 { 986 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT || 987 (int)NETKIT_PASS != (int)TCX_PASS || 988 (int)NETKIT_DROP != (int)TCX_DROP || 989 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT); 990 991 return rtnl_link_register(&netkit_link_ops); 992 } 993 994 static __exit void netkit_exit(void) 995 { 996 rtnl_link_unregister(&netkit_link_ops); 997 } 998 999 module_init(netkit_init); 1000 module_exit(netkit_exit); 1001 1002 MODULE_DESCRIPTION("BPF-programmable network device"); 1003 MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>"); 1004 MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>"); 1005 MODULE_LICENSE("GPL"); 1006 MODULE_ALIAS_RTNL_LINK(DRV_NAME); 1007