1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/sched/act_mirred.c packet mirroring and redirect actions 4 * 5 * Authors: Jamal Hadi Salim (2002-4) 6 * 7 * TODO: Add ingress support (and socket redirect support) 8 */ 9 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/string.h> 13 #include <linux/errno.h> 14 #include <linux/skbuff.h> 15 #include <linux/rtnetlink.h> 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/gfp.h> 19 #include <linux/if_arp.h> 20 #include <net/net_namespace.h> 21 #include <net/netlink.h> 22 #include <net/dst.h> 23 #include <net/pkt_sched.h> 24 #include <net/pkt_cls.h> 25 #include <linux/tc_act/tc_mirred.h> 26 #include <net/tc_act/tc_mirred.h> 27 #include <net/tc_wrapper.h> 28 29 static LIST_HEAD(mirred_list); 30 static DEFINE_SPINLOCK(mirred_list_lock); 31 32 #define MIRRED_NEST_LIMIT 4 33 static DEFINE_PER_CPU(unsigned int, mirred_nest_level); 34 35 static bool tcf_mirred_is_act_redirect(int action) 36 { 37 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR; 38 } 39 40 static bool tcf_mirred_act_wants_ingress(int action) 41 { 42 switch (action) { 43 case TCA_EGRESS_REDIR: 44 case TCA_EGRESS_MIRROR: 45 return false; 46 case TCA_INGRESS_REDIR: 47 case TCA_INGRESS_MIRROR: 48 return true; 49 default: 50 BUG(); 51 } 52 } 53 54 static bool tcf_mirred_can_reinsert(int action) 55 { 56 switch (action) { 57 case TC_ACT_SHOT: 58 case TC_ACT_STOLEN: 59 case TC_ACT_QUEUED: 60 case TC_ACT_TRAP: 61 return true; 62 } 63 return false; 64 } 65 66 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m) 67 { 68 return rcu_dereference_protected(m->tcfm_dev, 69 lockdep_is_held(&m->tcf_lock)); 70 } 71 72 static void tcf_mirred_release(struct tc_action *a) 73 { 74 struct tcf_mirred *m = to_mirred(a); 75 struct net_device *dev; 76 77 spin_lock(&mirred_list_lock); 78 list_del(&m->tcfm_list); 79 spin_unlock(&mirred_list_lock); 80 81 /* last reference to action, no need to lock */ 82 dev = rcu_dereference_protected(m->tcfm_dev, 1); 83 netdev_put(dev, &m->tcfm_dev_tracker); 84 } 85 86 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 87 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 88 }; 89 90 static struct tc_action_ops act_mirred_ops; 91 92 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 93 struct nlattr *est, struct tc_action **a, 94 struct tcf_proto *tp, 95 u32 flags, struct netlink_ext_ack *extack) 96 { 97 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id); 98 bool bind = flags & TCA_ACT_FLAGS_BIND; 99 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 100 struct tcf_chain *goto_ch = NULL; 101 bool mac_header_xmit = false; 102 struct tc_mirred *parm; 103 struct tcf_mirred *m; 104 bool exists = false; 105 int ret, err; 106 u32 index; 107 108 if (!nla) { 109 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed"); 110 return -EINVAL; 111 } 112 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla, 113 mirred_policy, extack); 114 if (ret < 0) 115 return ret; 116 if (!tb[TCA_MIRRED_PARMS]) { 117 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters"); 118 return -EINVAL; 119 } 120 parm = nla_data(tb[TCA_MIRRED_PARMS]); 121 index = parm->index; 122 err = tcf_idr_check_alloc(tn, &index, a, bind); 123 if (err < 0) 124 return err; 125 exists = err; 126 if (exists && bind) 127 return 0; 128 129 switch (parm->eaction) { 130 case TCA_EGRESS_MIRROR: 131 case TCA_EGRESS_REDIR: 132 case TCA_INGRESS_REDIR: 133 case TCA_INGRESS_MIRROR: 134 break; 135 default: 136 if (exists) 137 tcf_idr_release(*a, bind); 138 else 139 tcf_idr_cleanup(tn, index); 140 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option"); 141 return -EINVAL; 142 } 143 144 if (!exists) { 145 if (!parm->ifindex) { 146 tcf_idr_cleanup(tn, index); 147 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist"); 148 return -EINVAL; 149 } 150 ret = tcf_idr_create_from_flags(tn, index, est, a, 151 &act_mirred_ops, bind, flags); 152 if (ret) { 153 tcf_idr_cleanup(tn, index); 154 return ret; 155 } 156 ret = ACT_P_CREATED; 157 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 158 tcf_idr_release(*a, bind); 159 return -EEXIST; 160 } 161 162 m = to_mirred(*a); 163 if (ret == ACT_P_CREATED) 164 INIT_LIST_HEAD(&m->tcfm_list); 165 166 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 167 if (err < 0) 168 goto release_idr; 169 170 spin_lock_bh(&m->tcf_lock); 171 172 if (parm->ifindex) { 173 struct net_device *odev, *ndev; 174 175 ndev = dev_get_by_index(net, parm->ifindex); 176 if (!ndev) { 177 spin_unlock_bh(&m->tcf_lock); 178 err = -ENODEV; 179 goto put_chain; 180 } 181 mac_header_xmit = dev_is_mac_header_xmit(ndev); 182 odev = rcu_replace_pointer(m->tcfm_dev, ndev, 183 lockdep_is_held(&m->tcf_lock)); 184 netdev_put(odev, &m->tcfm_dev_tracker); 185 netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC); 186 m->tcfm_mac_header_xmit = mac_header_xmit; 187 } 188 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 189 m->tcfm_eaction = parm->eaction; 190 spin_unlock_bh(&m->tcf_lock); 191 if (goto_ch) 192 tcf_chain_put_by_act(goto_ch); 193 194 if (ret == ACT_P_CREATED) { 195 spin_lock(&mirred_list_lock); 196 list_add(&m->tcfm_list, &mirred_list); 197 spin_unlock(&mirred_list_lock); 198 } 199 200 return ret; 201 put_chain: 202 if (goto_ch) 203 tcf_chain_put_by_act(goto_ch); 204 release_idr: 205 tcf_idr_release(*a, bind); 206 return err; 207 } 208 209 static int 210 tcf_mirred_forward(bool at_ingress, bool want_ingress, struct sk_buff *skb) 211 { 212 int err; 213 214 if (!want_ingress) 215 err = tcf_dev_queue_xmit(skb, dev_queue_xmit); 216 else if (!at_ingress) 217 err = netif_rx(skb); 218 else 219 err = netif_receive_skb(skb); 220 221 return err; 222 } 223 224 static int tcf_mirred_to_dev(struct sk_buff *skb, struct tcf_mirred *m, 225 struct net_device *dev, 226 const bool m_mac_header_xmit, int m_eaction, 227 int retval) 228 { 229 struct sk_buff *skb_to_send = skb; 230 bool want_ingress; 231 bool is_redirect; 232 bool expects_nh; 233 bool at_ingress; 234 bool dont_clone; 235 int mac_len; 236 bool at_nh; 237 int err; 238 239 is_redirect = tcf_mirred_is_act_redirect(m_eaction); 240 if (unlikely(!(dev->flags & IFF_UP)) || !netif_carrier_ok(dev)) { 241 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 242 dev->name); 243 goto err_cant_do; 244 } 245 246 /* we could easily avoid the clone only if called by ingress and clsact; 247 * since we can't easily detect the clsact caller, skip clone only for 248 * ingress - that covers the TC S/W datapath. 249 */ 250 at_ingress = skb_at_tc_ingress(skb); 251 dont_clone = skb_at_tc_ingress(skb) && is_redirect && 252 tcf_mirred_can_reinsert(retval); 253 if (!dont_clone) { 254 skb_to_send = skb_clone(skb, GFP_ATOMIC); 255 if (!skb_to_send) 256 goto err_cant_do; 257 } 258 259 want_ingress = tcf_mirred_act_wants_ingress(m_eaction); 260 261 /* All mirred/redirected skbs should clear previous ct info */ 262 nf_reset_ct(skb_to_send); 263 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */ 264 skb_dst_drop(skb_to_send); 265 266 expects_nh = want_ingress || !m_mac_header_xmit; 267 at_nh = skb->data == skb_network_header(skb); 268 if (at_nh != expects_nh) { 269 mac_len = at_ingress ? skb->mac_len : 270 skb_network_offset(skb); 271 if (expects_nh) { 272 /* target device/action expect data at nh */ 273 skb_pull_rcsum(skb_to_send, mac_len); 274 } else { 275 /* target device/action expect data at mac */ 276 skb_push_rcsum(skb_to_send, mac_len); 277 } 278 } 279 280 skb_to_send->skb_iif = skb->dev->ifindex; 281 skb_to_send->dev = dev; 282 283 if (is_redirect) { 284 if (skb == skb_to_send) 285 retval = TC_ACT_CONSUMED; 286 287 skb_set_redirected(skb_to_send, skb_to_send->tc_at_ingress); 288 289 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send); 290 } else { 291 err = tcf_mirred_forward(at_ingress, want_ingress, skb_to_send); 292 } 293 if (err) 294 tcf_action_inc_overlimit_qstats(&m->common); 295 296 return retval; 297 298 err_cant_do: 299 if (is_redirect) 300 retval = TC_ACT_SHOT; 301 tcf_action_inc_overlimit_qstats(&m->common); 302 return retval; 303 } 304 305 TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, 306 const struct tc_action *a, 307 struct tcf_result *res) 308 { 309 struct tcf_mirred *m = to_mirred(a); 310 int retval = READ_ONCE(m->tcf_action); 311 unsigned int nest_level; 312 bool m_mac_header_xmit; 313 struct net_device *dev; 314 int m_eaction; 315 316 nest_level = __this_cpu_inc_return(mirred_nest_level); 317 if (unlikely(nest_level > MIRRED_NEST_LIMIT)) { 318 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n", 319 netdev_name(skb->dev)); 320 retval = TC_ACT_SHOT; 321 goto dec_nest_level; 322 } 323 324 tcf_lastuse_update(&m->tcf_tm); 325 tcf_action_update_bstats(&m->common, skb); 326 327 dev = rcu_dereference_bh(m->tcfm_dev); 328 if (unlikely(!dev)) { 329 pr_notice_once("tc mirred: target device is gone\n"); 330 tcf_action_inc_overlimit_qstats(&m->common); 331 goto dec_nest_level; 332 } 333 334 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); 335 m_eaction = READ_ONCE(m->tcfm_eaction); 336 337 retval = tcf_mirred_to_dev(skb, m, dev, m_mac_header_xmit, m_eaction, 338 retval); 339 340 dec_nest_level: 341 __this_cpu_dec(mirred_nest_level); 342 343 return retval; 344 } 345 346 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets, 347 u64 drops, u64 lastuse, bool hw) 348 { 349 struct tcf_mirred *m = to_mirred(a); 350 struct tcf_t *tm = &m->tcf_tm; 351 352 tcf_action_update_stats(a, bytes, packets, drops, hw); 353 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 354 } 355 356 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, 357 int ref) 358 { 359 unsigned char *b = skb_tail_pointer(skb); 360 struct tcf_mirred *m = to_mirred(a); 361 struct tc_mirred opt = { 362 .index = m->tcf_index, 363 .refcnt = refcount_read(&m->tcf_refcnt) - ref, 364 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind, 365 }; 366 struct net_device *dev; 367 struct tcf_t t; 368 369 spin_lock_bh(&m->tcf_lock); 370 opt.action = m->tcf_action; 371 opt.eaction = m->tcfm_eaction; 372 dev = tcf_mirred_dev_dereference(m); 373 if (dev) 374 opt.ifindex = dev->ifindex; 375 376 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 377 goto nla_put_failure; 378 379 tcf_tm_dump(&t, &m->tcf_tm); 380 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) 381 goto nla_put_failure; 382 spin_unlock_bh(&m->tcf_lock); 383 384 return skb->len; 385 386 nla_put_failure: 387 spin_unlock_bh(&m->tcf_lock); 388 nlmsg_trim(skb, b); 389 return -1; 390 } 391 392 static int mirred_device_event(struct notifier_block *unused, 393 unsigned long event, void *ptr) 394 { 395 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 396 struct tcf_mirred *m; 397 398 ASSERT_RTNL(); 399 if (event == NETDEV_UNREGISTER) { 400 spin_lock(&mirred_list_lock); 401 list_for_each_entry(m, &mirred_list, tcfm_list) { 402 spin_lock_bh(&m->tcf_lock); 403 if (tcf_mirred_dev_dereference(m) == dev) { 404 netdev_put(dev, &m->tcfm_dev_tracker); 405 /* Note : no rcu grace period necessary, as 406 * net_device are already rcu protected. 407 */ 408 RCU_INIT_POINTER(m->tcfm_dev, NULL); 409 } 410 spin_unlock_bh(&m->tcf_lock); 411 } 412 spin_unlock(&mirred_list_lock); 413 } 414 415 return NOTIFY_DONE; 416 } 417 418 static struct notifier_block mirred_device_notifier = { 419 .notifier_call = mirred_device_event, 420 }; 421 422 static void tcf_mirred_dev_put(void *priv) 423 { 424 struct net_device *dev = priv; 425 426 dev_put(dev); 427 } 428 429 static struct net_device * 430 tcf_mirred_get_dev(const struct tc_action *a, 431 tc_action_priv_destructor *destructor) 432 { 433 struct tcf_mirred *m = to_mirred(a); 434 struct net_device *dev; 435 436 rcu_read_lock(); 437 dev = rcu_dereference(m->tcfm_dev); 438 if (dev) { 439 dev_hold(dev); 440 *destructor = tcf_mirred_dev_put; 441 } 442 rcu_read_unlock(); 443 444 return dev; 445 } 446 447 static size_t tcf_mirred_get_fill_size(const struct tc_action *act) 448 { 449 return nla_total_size(sizeof(struct tc_mirred)); 450 } 451 452 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry, 453 const struct tc_action *act) 454 { 455 entry->dev = act->ops->get_dev(act, &entry->destructor); 456 if (!entry->dev) 457 return; 458 entry->destructor_priv = entry->dev; 459 } 460 461 static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data, 462 u32 *index_inc, bool bind, 463 struct netlink_ext_ack *extack) 464 { 465 if (bind) { 466 struct flow_action_entry *entry = entry_data; 467 468 if (is_tcf_mirred_egress_redirect(act)) { 469 entry->id = FLOW_ACTION_REDIRECT; 470 tcf_offload_mirred_get_dev(entry, act); 471 } else if (is_tcf_mirred_egress_mirror(act)) { 472 entry->id = FLOW_ACTION_MIRRED; 473 tcf_offload_mirred_get_dev(entry, act); 474 } else if (is_tcf_mirred_ingress_redirect(act)) { 475 entry->id = FLOW_ACTION_REDIRECT_INGRESS; 476 tcf_offload_mirred_get_dev(entry, act); 477 } else if (is_tcf_mirred_ingress_mirror(act)) { 478 entry->id = FLOW_ACTION_MIRRED_INGRESS; 479 tcf_offload_mirred_get_dev(entry, act); 480 } else { 481 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload"); 482 return -EOPNOTSUPP; 483 } 484 *index_inc = 1; 485 } else { 486 struct flow_offload_action *fl_action = entry_data; 487 488 if (is_tcf_mirred_egress_redirect(act)) 489 fl_action->id = FLOW_ACTION_REDIRECT; 490 else if (is_tcf_mirred_egress_mirror(act)) 491 fl_action->id = FLOW_ACTION_MIRRED; 492 else if (is_tcf_mirred_ingress_redirect(act)) 493 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS; 494 else if (is_tcf_mirred_ingress_mirror(act)) 495 fl_action->id = FLOW_ACTION_MIRRED_INGRESS; 496 else 497 return -EOPNOTSUPP; 498 } 499 500 return 0; 501 } 502 503 static struct tc_action_ops act_mirred_ops = { 504 .kind = "mirred", 505 .id = TCA_ID_MIRRED, 506 .owner = THIS_MODULE, 507 .act = tcf_mirred_act, 508 .stats_update = tcf_stats_update, 509 .dump = tcf_mirred_dump, 510 .cleanup = tcf_mirred_release, 511 .init = tcf_mirred_init, 512 .get_fill_size = tcf_mirred_get_fill_size, 513 .offload_act_setup = tcf_mirred_offload_act_setup, 514 .size = sizeof(struct tcf_mirred), 515 .get_dev = tcf_mirred_get_dev, 516 }; 517 518 static __net_init int mirred_init_net(struct net *net) 519 { 520 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id); 521 522 return tc_action_net_init(net, tn, &act_mirred_ops); 523 } 524 525 static void __net_exit mirred_exit_net(struct list_head *net_list) 526 { 527 tc_action_net_exit(net_list, act_mirred_ops.net_id); 528 } 529 530 static struct pernet_operations mirred_net_ops = { 531 .init = mirred_init_net, 532 .exit_batch = mirred_exit_net, 533 .id = &act_mirred_ops.net_id, 534 .size = sizeof(struct tc_action_net), 535 }; 536 537 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 538 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 539 MODULE_LICENSE("GPL"); 540 541 static int __init mirred_init_module(void) 542 { 543 int err = register_netdevice_notifier(&mirred_device_notifier); 544 if (err) 545 return err; 546 547 pr_info("Mirror/redirect action on\n"); 548 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops); 549 if (err) 550 unregister_netdevice_notifier(&mirred_device_notifier); 551 552 return err; 553 } 554 555 static void __exit mirred_cleanup_module(void) 556 { 557 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); 558 unregister_netdevice_notifier(&mirred_device_notifier); 559 } 560 561 module_init(mirred_init_module); 562 module_exit(mirred_cleanup_module); 563