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 *peer_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 int err; 346 347 if (data) { 348 if (data[IFLA_NETKIT_MODE]) 349 mode = nla_get_u32(data[IFLA_NETKIT_MODE]); 350 if (data[IFLA_NETKIT_PEER_INFO]) { 351 attr = data[IFLA_NETKIT_PEER_INFO]; 352 ifmp = nla_data(attr); 353 rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack); 354 tbp = peer_tb; 355 } 356 if (data[IFLA_NETKIT_SCRUB]) 357 scrub_prim = nla_get_u32(data[IFLA_NETKIT_SCRUB]); 358 if (data[IFLA_NETKIT_PEER_SCRUB]) 359 scrub_peer = nla_get_u32(data[IFLA_NETKIT_PEER_SCRUB]); 360 if (data[IFLA_NETKIT_POLICY]) { 361 attr = data[IFLA_NETKIT_POLICY]; 362 policy_prim = nla_get_u32(attr); 363 err = netkit_check_policy(policy_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 policy_peer = nla_get_u32(attr); 370 err = netkit_check_policy(policy_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 peer = rtnl_create_link(peer_net, ifname, ifname_assign_type, 388 &netkit_link_ops, tbp, extack); 389 if (IS_ERR(peer)) 390 return PTR_ERR(peer); 391 392 netif_inherit_tso_max(peer, dev); 393 394 if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS])) 395 eth_hw_addr_random(peer); 396 if (ifmp && dev->ifindex) 397 peer->ifindex = ifmp->ifi_index; 398 399 nk = netkit_priv(peer); 400 nk->primary = false; 401 nk->policy = policy_peer; 402 nk->scrub = scrub_peer; 403 nk->mode = mode; 404 bpf_mprog_bundle_init(&nk->bundle); 405 406 err = register_netdevice(peer); 407 if (err < 0) 408 goto err_register_peer; 409 netif_carrier_off(peer); 410 if (mode == NETKIT_L2) 411 dev_change_flags(peer, peer->flags & ~IFF_NOARP, NULL); 412 413 err = rtnl_configure_link(peer, NULL, 0, NULL); 414 if (err < 0) 415 goto err_configure_peer; 416 417 if (mode == NETKIT_L2 && !tb[IFLA_ADDRESS]) 418 eth_hw_addr_random(dev); 419 if (tb[IFLA_IFNAME]) 420 nla_strscpy(dev->name, tb[IFLA_IFNAME], IFNAMSIZ); 421 else 422 strscpy(dev->name, "nk%d", IFNAMSIZ); 423 424 nk = netkit_priv(dev); 425 nk->primary = true; 426 nk->policy = policy_prim; 427 nk->scrub = scrub_prim; 428 nk->mode = mode; 429 bpf_mprog_bundle_init(&nk->bundle); 430 431 err = register_netdevice(dev); 432 if (err < 0) 433 goto err_configure_peer; 434 netif_carrier_off(dev); 435 if (mode == NETKIT_L2) 436 dev_change_flags(dev, dev->flags & ~IFF_NOARP, NULL); 437 438 rcu_assign_pointer(netkit_priv(dev)->peer, peer); 439 rcu_assign_pointer(netkit_priv(peer)->peer, dev); 440 return 0; 441 err_configure_peer: 442 unregister_netdevice(peer); 443 return err; 444 err_register_peer: 445 free_netdev(peer); 446 return err; 447 } 448 449 static struct bpf_mprog_entry *netkit_entry_fetch(struct net_device *dev, 450 bool bundle_fallback) 451 { 452 struct netkit *nk = netkit_priv(dev); 453 struct bpf_mprog_entry *entry; 454 455 ASSERT_RTNL(); 456 entry = rcu_dereference_rtnl(nk->active); 457 if (entry) 458 return entry; 459 if (bundle_fallback) 460 return &nk->bundle.a; 461 return NULL; 462 } 463 464 static void netkit_entry_update(struct net_device *dev, 465 struct bpf_mprog_entry *entry) 466 { 467 struct netkit *nk = netkit_priv(dev); 468 469 ASSERT_RTNL(); 470 rcu_assign_pointer(nk->active, entry); 471 } 472 473 static void netkit_entry_sync(void) 474 { 475 synchronize_rcu(); 476 } 477 478 static struct net_device *netkit_dev_fetch(struct net *net, u32 ifindex, u32 which) 479 { 480 struct net_device *dev; 481 struct netkit *nk; 482 483 ASSERT_RTNL(); 484 485 switch (which) { 486 case BPF_NETKIT_PRIMARY: 487 case BPF_NETKIT_PEER: 488 break; 489 default: 490 return ERR_PTR(-EINVAL); 491 } 492 493 dev = __dev_get_by_index(net, ifindex); 494 if (!dev) 495 return ERR_PTR(-ENODEV); 496 if (dev->netdev_ops != &netkit_netdev_ops) 497 return ERR_PTR(-ENXIO); 498 499 nk = netkit_priv(dev); 500 if (!nk->primary) 501 return ERR_PTR(-EACCES); 502 if (which == BPF_NETKIT_PEER) { 503 dev = rcu_dereference_rtnl(nk->peer); 504 if (!dev) 505 return ERR_PTR(-ENODEV); 506 } 507 return dev; 508 } 509 510 int netkit_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) 511 { 512 struct bpf_mprog_entry *entry, *entry_new; 513 struct bpf_prog *replace_prog = NULL; 514 struct net_device *dev; 515 int ret; 516 517 rtnl_lock(); 518 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 519 attr->attach_type); 520 if (IS_ERR(dev)) { 521 ret = PTR_ERR(dev); 522 goto out; 523 } 524 entry = netkit_entry_fetch(dev, true); 525 if (attr->attach_flags & BPF_F_REPLACE) { 526 replace_prog = bpf_prog_get_type(attr->replace_bpf_fd, 527 prog->type); 528 if (IS_ERR(replace_prog)) { 529 ret = PTR_ERR(replace_prog); 530 replace_prog = NULL; 531 goto out; 532 } 533 } 534 ret = bpf_mprog_attach(entry, &entry_new, prog, NULL, replace_prog, 535 attr->attach_flags, attr->relative_fd, 536 attr->expected_revision); 537 if (!ret) { 538 if (entry != entry_new) { 539 netkit_entry_update(dev, entry_new); 540 netkit_entry_sync(); 541 } 542 bpf_mprog_commit(entry); 543 } 544 out: 545 if (replace_prog) 546 bpf_prog_put(replace_prog); 547 rtnl_unlock(); 548 return ret; 549 } 550 551 int netkit_prog_detach(const union bpf_attr *attr, struct bpf_prog *prog) 552 { 553 struct bpf_mprog_entry *entry, *entry_new; 554 struct net_device *dev; 555 int ret; 556 557 rtnl_lock(); 558 dev = netkit_dev_fetch(current->nsproxy->net_ns, attr->target_ifindex, 559 attr->attach_type); 560 if (IS_ERR(dev)) { 561 ret = PTR_ERR(dev); 562 goto out; 563 } 564 entry = netkit_entry_fetch(dev, false); 565 if (!entry) { 566 ret = -ENOENT; 567 goto out; 568 } 569 ret = bpf_mprog_detach(entry, &entry_new, prog, NULL, attr->attach_flags, 570 attr->relative_fd, attr->expected_revision); 571 if (!ret) { 572 if (!bpf_mprog_total(entry_new)) 573 entry_new = NULL; 574 netkit_entry_update(dev, entry_new); 575 netkit_entry_sync(); 576 bpf_mprog_commit(entry); 577 } 578 out: 579 rtnl_unlock(); 580 return ret; 581 } 582 583 int netkit_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) 584 { 585 struct net_device *dev; 586 int ret; 587 588 rtnl_lock(); 589 dev = netkit_dev_fetch(current->nsproxy->net_ns, 590 attr->query.target_ifindex, 591 attr->query.attach_type); 592 if (IS_ERR(dev)) { 593 ret = PTR_ERR(dev); 594 goto out; 595 } 596 ret = bpf_mprog_query(attr, uattr, netkit_entry_fetch(dev, false)); 597 out: 598 rtnl_unlock(); 599 return ret; 600 } 601 602 static struct netkit_link *netkit_link(const struct bpf_link *link) 603 { 604 return container_of(link, struct netkit_link, link); 605 } 606 607 static int netkit_link_prog_attach(struct bpf_link *link, u32 flags, 608 u32 id_or_fd, u64 revision) 609 { 610 struct netkit_link *nkl = netkit_link(link); 611 struct bpf_mprog_entry *entry, *entry_new; 612 struct net_device *dev = nkl->dev; 613 int ret; 614 615 ASSERT_RTNL(); 616 entry = netkit_entry_fetch(dev, true); 617 ret = bpf_mprog_attach(entry, &entry_new, link->prog, link, NULL, flags, 618 id_or_fd, revision); 619 if (!ret) { 620 if (entry != entry_new) { 621 netkit_entry_update(dev, entry_new); 622 netkit_entry_sync(); 623 } 624 bpf_mprog_commit(entry); 625 } 626 return ret; 627 } 628 629 static void netkit_link_release(struct bpf_link *link) 630 { 631 struct netkit_link *nkl = netkit_link(link); 632 struct bpf_mprog_entry *entry, *entry_new; 633 struct net_device *dev; 634 int ret = 0; 635 636 rtnl_lock(); 637 dev = nkl->dev; 638 if (!dev) 639 goto out; 640 entry = netkit_entry_fetch(dev, false); 641 if (!entry) { 642 ret = -ENOENT; 643 goto out; 644 } 645 ret = bpf_mprog_detach(entry, &entry_new, link->prog, link, 0, 0, 0); 646 if (!ret) { 647 if (!bpf_mprog_total(entry_new)) 648 entry_new = NULL; 649 netkit_entry_update(dev, entry_new); 650 netkit_entry_sync(); 651 bpf_mprog_commit(entry); 652 nkl->dev = NULL; 653 } 654 out: 655 WARN_ON_ONCE(ret); 656 rtnl_unlock(); 657 } 658 659 static int netkit_link_update(struct bpf_link *link, struct bpf_prog *nprog, 660 struct bpf_prog *oprog) 661 { 662 struct netkit_link *nkl = netkit_link(link); 663 struct bpf_mprog_entry *entry, *entry_new; 664 struct net_device *dev; 665 int ret = 0; 666 667 rtnl_lock(); 668 dev = nkl->dev; 669 if (!dev) { 670 ret = -ENOLINK; 671 goto out; 672 } 673 if (oprog && link->prog != oprog) { 674 ret = -EPERM; 675 goto out; 676 } 677 oprog = link->prog; 678 if (oprog == nprog) { 679 bpf_prog_put(nprog); 680 goto out; 681 } 682 entry = netkit_entry_fetch(dev, false); 683 if (!entry) { 684 ret = -ENOENT; 685 goto out; 686 } 687 ret = bpf_mprog_attach(entry, &entry_new, nprog, link, oprog, 688 BPF_F_REPLACE | BPF_F_ID, 689 link->prog->aux->id, 0); 690 if (!ret) { 691 WARN_ON_ONCE(entry != entry_new); 692 oprog = xchg(&link->prog, nprog); 693 bpf_prog_put(oprog); 694 bpf_mprog_commit(entry); 695 } 696 out: 697 rtnl_unlock(); 698 return ret; 699 } 700 701 static void netkit_link_dealloc(struct bpf_link *link) 702 { 703 kfree(netkit_link(link)); 704 } 705 706 static void netkit_link_fdinfo(const struct bpf_link *link, struct seq_file *seq) 707 { 708 const struct netkit_link *nkl = netkit_link(link); 709 u32 ifindex = 0; 710 711 rtnl_lock(); 712 if (nkl->dev) 713 ifindex = nkl->dev->ifindex; 714 rtnl_unlock(); 715 716 seq_printf(seq, "ifindex:\t%u\n", ifindex); 717 seq_printf(seq, "attach_type:\t%u (%s)\n", 718 nkl->location, 719 nkl->location == BPF_NETKIT_PRIMARY ? "primary" : "peer"); 720 } 721 722 static int netkit_link_fill_info(const struct bpf_link *link, 723 struct bpf_link_info *info) 724 { 725 const struct netkit_link *nkl = netkit_link(link); 726 u32 ifindex = 0; 727 728 rtnl_lock(); 729 if (nkl->dev) 730 ifindex = nkl->dev->ifindex; 731 rtnl_unlock(); 732 733 info->netkit.ifindex = ifindex; 734 info->netkit.attach_type = nkl->location; 735 return 0; 736 } 737 738 static int netkit_link_detach(struct bpf_link *link) 739 { 740 netkit_link_release(link); 741 return 0; 742 } 743 744 static const struct bpf_link_ops netkit_link_lops = { 745 .release = netkit_link_release, 746 .detach = netkit_link_detach, 747 .dealloc = netkit_link_dealloc, 748 .update_prog = netkit_link_update, 749 .show_fdinfo = netkit_link_fdinfo, 750 .fill_link_info = netkit_link_fill_info, 751 }; 752 753 static int netkit_link_init(struct netkit_link *nkl, 754 struct bpf_link_primer *link_primer, 755 const union bpf_attr *attr, 756 struct net_device *dev, 757 struct bpf_prog *prog) 758 { 759 bpf_link_init(&nkl->link, BPF_LINK_TYPE_NETKIT, 760 &netkit_link_lops, prog); 761 nkl->location = attr->link_create.attach_type; 762 nkl->dev = dev; 763 return bpf_link_prime(&nkl->link, link_primer); 764 } 765 766 int netkit_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 767 { 768 struct bpf_link_primer link_primer; 769 struct netkit_link *nkl; 770 struct net_device *dev; 771 int ret; 772 773 rtnl_lock(); 774 dev = netkit_dev_fetch(current->nsproxy->net_ns, 775 attr->link_create.target_ifindex, 776 attr->link_create.attach_type); 777 if (IS_ERR(dev)) { 778 ret = PTR_ERR(dev); 779 goto out; 780 } 781 nkl = kzalloc(sizeof(*nkl), GFP_KERNEL_ACCOUNT); 782 if (!nkl) { 783 ret = -ENOMEM; 784 goto out; 785 } 786 ret = netkit_link_init(nkl, &link_primer, attr, dev, prog); 787 if (ret) { 788 kfree(nkl); 789 goto out; 790 } 791 ret = netkit_link_prog_attach(&nkl->link, 792 attr->link_create.flags, 793 attr->link_create.netkit.relative_fd, 794 attr->link_create.netkit.expected_revision); 795 if (ret) { 796 nkl->dev = NULL; 797 bpf_link_cleanup(&link_primer); 798 goto out; 799 } 800 ret = bpf_link_settle(&link_primer); 801 out: 802 rtnl_unlock(); 803 return ret; 804 } 805 806 static void netkit_release_all(struct net_device *dev) 807 { 808 struct bpf_mprog_entry *entry; 809 struct bpf_tuple tuple = {}; 810 struct bpf_mprog_fp *fp; 811 struct bpf_mprog_cp *cp; 812 813 entry = netkit_entry_fetch(dev, false); 814 if (!entry) 815 return; 816 netkit_entry_update(dev, NULL); 817 netkit_entry_sync(); 818 bpf_mprog_foreach_tuple(entry, fp, cp, tuple) { 819 if (tuple.link) 820 netkit_link(tuple.link)->dev = NULL; 821 else 822 bpf_prog_put(tuple.prog); 823 } 824 } 825 826 static void netkit_uninit(struct net_device *dev) 827 { 828 netkit_release_all(dev); 829 } 830 831 static void netkit_del_link(struct net_device *dev, struct list_head *head) 832 { 833 struct netkit *nk = netkit_priv(dev); 834 struct net_device *peer = rtnl_dereference(nk->peer); 835 836 RCU_INIT_POINTER(nk->peer, NULL); 837 unregister_netdevice_queue(dev, head); 838 if (peer) { 839 nk = netkit_priv(peer); 840 RCU_INIT_POINTER(nk->peer, NULL); 841 unregister_netdevice_queue(peer, head); 842 } 843 } 844 845 static int netkit_change_link(struct net_device *dev, struct nlattr *tb[], 846 struct nlattr *data[], 847 struct netlink_ext_ack *extack) 848 { 849 struct netkit *nk = netkit_priv(dev); 850 struct net_device *peer = rtnl_dereference(nk->peer); 851 enum netkit_action policy; 852 struct nlattr *attr; 853 int err; 854 855 if (!nk->primary) { 856 NL_SET_ERR_MSG(extack, 857 "netkit link settings can be changed only through the primary device"); 858 return -EACCES; 859 } 860 861 if (data[IFLA_NETKIT_MODE]) { 862 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE], 863 "netkit link operating mode cannot be changed after device creation"); 864 return -EACCES; 865 } 866 867 if (data[IFLA_NETKIT_SCRUB]) { 868 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_SCRUB], 869 "netkit scrubbing cannot be changed after device creation"); 870 return -EACCES; 871 } 872 873 if (data[IFLA_NETKIT_PEER_SCRUB]) { 874 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_SCRUB], 875 "netkit scrubbing cannot be changed after device creation"); 876 return -EACCES; 877 } 878 879 if (data[IFLA_NETKIT_PEER_INFO]) { 880 NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO], 881 "netkit peer info cannot be changed after device creation"); 882 return -EINVAL; 883 } 884 885 if (data[IFLA_NETKIT_POLICY]) { 886 attr = data[IFLA_NETKIT_POLICY]; 887 policy = nla_get_u32(attr); 888 err = netkit_check_policy(policy, attr, extack); 889 if (err) 890 return err; 891 WRITE_ONCE(nk->policy, policy); 892 } 893 894 if (data[IFLA_NETKIT_PEER_POLICY]) { 895 err = -EOPNOTSUPP; 896 attr = data[IFLA_NETKIT_PEER_POLICY]; 897 policy = nla_get_u32(attr); 898 if (peer) 899 err = netkit_check_policy(policy, attr, extack); 900 if (err) 901 return err; 902 nk = netkit_priv(peer); 903 WRITE_ONCE(nk->policy, policy); 904 } 905 906 return 0; 907 } 908 909 static size_t netkit_get_size(const struct net_device *dev) 910 { 911 return nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_POLICY */ 912 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_POLICY */ 913 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_SCRUB */ 914 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_SCRUB */ 915 nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */ 916 nla_total_size(sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */ 917 0; 918 } 919 920 static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev) 921 { 922 struct netkit *nk = netkit_priv(dev); 923 struct net_device *peer = rtnl_dereference(nk->peer); 924 925 if (nla_put_u8(skb, IFLA_NETKIT_PRIMARY, nk->primary)) 926 return -EMSGSIZE; 927 if (nla_put_u32(skb, IFLA_NETKIT_POLICY, nk->policy)) 928 return -EMSGSIZE; 929 if (nla_put_u32(skb, IFLA_NETKIT_MODE, nk->mode)) 930 return -EMSGSIZE; 931 if (nla_put_u32(skb, IFLA_NETKIT_SCRUB, nk->scrub)) 932 return -EMSGSIZE; 933 934 if (peer) { 935 nk = netkit_priv(peer); 936 if (nla_put_u32(skb, IFLA_NETKIT_PEER_POLICY, nk->policy)) 937 return -EMSGSIZE; 938 if (nla_put_u32(skb, IFLA_NETKIT_PEER_SCRUB, nk->scrub)) 939 return -EMSGSIZE; 940 } 941 942 return 0; 943 } 944 945 static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = { 946 [IFLA_NETKIT_PEER_INFO] = { .len = sizeof(struct ifinfomsg) }, 947 [IFLA_NETKIT_MODE] = NLA_POLICY_MAX(NLA_U32, NETKIT_L3), 948 [IFLA_NETKIT_POLICY] = { .type = NLA_U32 }, 949 [IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 }, 950 [IFLA_NETKIT_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT), 951 [IFLA_NETKIT_PEER_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT), 952 [IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT, 953 .reject_message = "Primary attribute is read-only" }, 954 }; 955 956 static struct rtnl_link_ops netkit_link_ops = { 957 .kind = DRV_NAME, 958 .priv_size = sizeof(struct netkit), 959 .setup = netkit_setup, 960 .newlink = netkit_new_link, 961 .dellink = netkit_del_link, 962 .changelink = netkit_change_link, 963 .get_link_net = netkit_get_link_net, 964 .get_size = netkit_get_size, 965 .fill_info = netkit_fill_info, 966 .policy = netkit_policy, 967 .validate = netkit_validate, 968 .peer_type = IFLA_NETKIT_PEER_INFO, 969 .maxtype = IFLA_NETKIT_MAX, 970 }; 971 972 static __init int netkit_init(void) 973 { 974 BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT || 975 (int)NETKIT_PASS != (int)TCX_PASS || 976 (int)NETKIT_DROP != (int)TCX_DROP || 977 (int)NETKIT_REDIRECT != (int)TCX_REDIRECT); 978 979 return rtnl_link_register(&netkit_link_ops); 980 } 981 982 static __exit void netkit_exit(void) 983 { 984 rtnl_link_unregister(&netkit_link_ops); 985 } 986 987 module_init(netkit_init); 988 module_exit(netkit_exit); 989 990 MODULE_DESCRIPTION("BPF-programmable network device"); 991 MODULE_AUTHOR("Daniel Borkmann <daniel@iogearbox.net>"); 992 MODULE_AUTHOR("Nikolay Aleksandrov <razor@blackwall.org>"); 993 MODULE_LICENSE("GPL"); 994 MODULE_ALIAS_RTNL_LINK(DRV_NAME); 995