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_RECURSION_LIMIT 4 33 static DEFINE_PER_CPU(unsigned int, mirred_rec_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 tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) 210 { 211 int err; 212 213 if (!want_ingress) 214 err = tcf_dev_queue_xmit(skb, dev_queue_xmit); 215 else 216 err = netif_receive_skb(skb); 217 218 return err; 219 } 220 221 TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, 222 const struct tc_action *a, 223 struct tcf_result *res) 224 { 225 struct tcf_mirred *m = to_mirred(a); 226 struct sk_buff *skb2 = skb; 227 bool m_mac_header_xmit; 228 struct net_device *dev; 229 unsigned int rec_level; 230 int retval, err = 0; 231 bool use_reinsert; 232 bool want_ingress; 233 bool is_redirect; 234 bool expects_nh; 235 bool at_ingress; 236 int m_eaction; 237 int mac_len; 238 bool at_nh; 239 240 rec_level = __this_cpu_inc_return(mirred_rec_level); 241 if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) { 242 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n", 243 netdev_name(skb->dev)); 244 __this_cpu_dec(mirred_rec_level); 245 return TC_ACT_SHOT; 246 } 247 248 tcf_lastuse_update(&m->tcf_tm); 249 tcf_action_update_bstats(&m->common, skb); 250 251 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); 252 m_eaction = READ_ONCE(m->tcfm_eaction); 253 retval = READ_ONCE(m->tcf_action); 254 dev = rcu_dereference_bh(m->tcfm_dev); 255 if (unlikely(!dev)) { 256 pr_notice_once("tc mirred: target device is gone\n"); 257 goto out; 258 } 259 260 if (unlikely(!(dev->flags & IFF_UP))) { 261 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 262 dev->name); 263 goto out; 264 } 265 266 /* we could easily avoid the clone only if called by ingress and clsact; 267 * since we can't easily detect the clsact caller, skip clone only for 268 * ingress - that covers the TC S/W datapath. 269 */ 270 is_redirect = tcf_mirred_is_act_redirect(m_eaction); 271 at_ingress = skb_at_tc_ingress(skb); 272 use_reinsert = at_ingress && is_redirect && 273 tcf_mirred_can_reinsert(retval); 274 if (!use_reinsert) { 275 skb2 = skb_clone(skb, GFP_ATOMIC); 276 if (!skb2) 277 goto out; 278 } 279 280 want_ingress = tcf_mirred_act_wants_ingress(m_eaction); 281 282 /* All mirred/redirected skbs should clear previous ct info */ 283 nf_reset_ct(skb2); 284 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */ 285 skb_dst_drop(skb2); 286 287 expects_nh = want_ingress || !m_mac_header_xmit; 288 at_nh = skb->data == skb_network_header(skb); 289 if (at_nh != expects_nh) { 290 mac_len = skb_at_tc_ingress(skb) ? skb->mac_len : 291 skb_network_header(skb) - skb_mac_header(skb); 292 if (expects_nh) { 293 /* target device/action expect data at nh */ 294 skb_pull_rcsum(skb2, mac_len); 295 } else { 296 /* target device/action expect data at mac */ 297 skb_push_rcsum(skb2, mac_len); 298 } 299 } 300 301 skb2->skb_iif = skb->dev->ifindex; 302 skb2->dev = dev; 303 304 /* mirror is always swallowed */ 305 if (is_redirect) { 306 skb_set_redirected(skb2, skb2->tc_at_ingress); 307 308 /* let's the caller reinsert the packet, if possible */ 309 if (use_reinsert) { 310 err = tcf_mirred_forward(want_ingress, skb); 311 if (err) 312 tcf_action_inc_overlimit_qstats(&m->common); 313 __this_cpu_dec(mirred_rec_level); 314 return TC_ACT_CONSUMED; 315 } 316 } 317 318 err = tcf_mirred_forward(want_ingress, skb2); 319 if (err) { 320 out: 321 tcf_action_inc_overlimit_qstats(&m->common); 322 if (tcf_mirred_is_act_redirect(m_eaction)) 323 retval = TC_ACT_SHOT; 324 } 325 __this_cpu_dec(mirred_rec_level); 326 327 return retval; 328 } 329 330 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets, 331 u64 drops, u64 lastuse, bool hw) 332 { 333 struct tcf_mirred *m = to_mirred(a); 334 struct tcf_t *tm = &m->tcf_tm; 335 336 tcf_action_update_stats(a, bytes, packets, drops, hw); 337 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 338 } 339 340 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, 341 int ref) 342 { 343 unsigned char *b = skb_tail_pointer(skb); 344 struct tcf_mirred *m = to_mirred(a); 345 struct tc_mirred opt = { 346 .index = m->tcf_index, 347 .refcnt = refcount_read(&m->tcf_refcnt) - ref, 348 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind, 349 }; 350 struct net_device *dev; 351 struct tcf_t t; 352 353 spin_lock_bh(&m->tcf_lock); 354 opt.action = m->tcf_action; 355 opt.eaction = m->tcfm_eaction; 356 dev = tcf_mirred_dev_dereference(m); 357 if (dev) 358 opt.ifindex = dev->ifindex; 359 360 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 361 goto nla_put_failure; 362 363 tcf_tm_dump(&t, &m->tcf_tm); 364 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) 365 goto nla_put_failure; 366 spin_unlock_bh(&m->tcf_lock); 367 368 return skb->len; 369 370 nla_put_failure: 371 spin_unlock_bh(&m->tcf_lock); 372 nlmsg_trim(skb, b); 373 return -1; 374 } 375 376 static int mirred_device_event(struct notifier_block *unused, 377 unsigned long event, void *ptr) 378 { 379 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 380 struct tcf_mirred *m; 381 382 ASSERT_RTNL(); 383 if (event == NETDEV_UNREGISTER) { 384 spin_lock(&mirred_list_lock); 385 list_for_each_entry(m, &mirred_list, tcfm_list) { 386 spin_lock_bh(&m->tcf_lock); 387 if (tcf_mirred_dev_dereference(m) == dev) { 388 netdev_put(dev, &m->tcfm_dev_tracker); 389 /* Note : no rcu grace period necessary, as 390 * net_device are already rcu protected. 391 */ 392 RCU_INIT_POINTER(m->tcfm_dev, NULL); 393 } 394 spin_unlock_bh(&m->tcf_lock); 395 } 396 spin_unlock(&mirred_list_lock); 397 } 398 399 return NOTIFY_DONE; 400 } 401 402 static struct notifier_block mirred_device_notifier = { 403 .notifier_call = mirred_device_event, 404 }; 405 406 static void tcf_mirred_dev_put(void *priv) 407 { 408 struct net_device *dev = priv; 409 410 dev_put(dev); 411 } 412 413 static struct net_device * 414 tcf_mirred_get_dev(const struct tc_action *a, 415 tc_action_priv_destructor *destructor) 416 { 417 struct tcf_mirred *m = to_mirred(a); 418 struct net_device *dev; 419 420 rcu_read_lock(); 421 dev = rcu_dereference(m->tcfm_dev); 422 if (dev) { 423 dev_hold(dev); 424 *destructor = tcf_mirred_dev_put; 425 } 426 rcu_read_unlock(); 427 428 return dev; 429 } 430 431 static size_t tcf_mirred_get_fill_size(const struct tc_action *act) 432 { 433 return nla_total_size(sizeof(struct tc_mirred)); 434 } 435 436 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry, 437 const struct tc_action *act) 438 { 439 entry->dev = act->ops->get_dev(act, &entry->destructor); 440 if (!entry->dev) 441 return; 442 entry->destructor_priv = entry->dev; 443 } 444 445 static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data, 446 u32 *index_inc, bool bind, 447 struct netlink_ext_ack *extack) 448 { 449 if (bind) { 450 struct flow_action_entry *entry = entry_data; 451 452 if (is_tcf_mirred_egress_redirect(act)) { 453 entry->id = FLOW_ACTION_REDIRECT; 454 tcf_offload_mirred_get_dev(entry, act); 455 } else if (is_tcf_mirred_egress_mirror(act)) { 456 entry->id = FLOW_ACTION_MIRRED; 457 tcf_offload_mirred_get_dev(entry, act); 458 } else if (is_tcf_mirred_ingress_redirect(act)) { 459 entry->id = FLOW_ACTION_REDIRECT_INGRESS; 460 tcf_offload_mirred_get_dev(entry, act); 461 } else if (is_tcf_mirred_ingress_mirror(act)) { 462 entry->id = FLOW_ACTION_MIRRED_INGRESS; 463 tcf_offload_mirred_get_dev(entry, act); 464 } else { 465 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload"); 466 return -EOPNOTSUPP; 467 } 468 *index_inc = 1; 469 } else { 470 struct flow_offload_action *fl_action = entry_data; 471 472 if (is_tcf_mirred_egress_redirect(act)) 473 fl_action->id = FLOW_ACTION_REDIRECT; 474 else if (is_tcf_mirred_egress_mirror(act)) 475 fl_action->id = FLOW_ACTION_MIRRED; 476 else if (is_tcf_mirred_ingress_redirect(act)) 477 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS; 478 else if (is_tcf_mirred_ingress_mirror(act)) 479 fl_action->id = FLOW_ACTION_MIRRED_INGRESS; 480 else 481 return -EOPNOTSUPP; 482 } 483 484 return 0; 485 } 486 487 static struct tc_action_ops act_mirred_ops = { 488 .kind = "mirred", 489 .id = TCA_ID_MIRRED, 490 .owner = THIS_MODULE, 491 .act = tcf_mirred_act, 492 .stats_update = tcf_stats_update, 493 .dump = tcf_mirred_dump, 494 .cleanup = tcf_mirred_release, 495 .init = tcf_mirred_init, 496 .get_fill_size = tcf_mirred_get_fill_size, 497 .offload_act_setup = tcf_mirred_offload_act_setup, 498 .size = sizeof(struct tcf_mirred), 499 .get_dev = tcf_mirred_get_dev, 500 }; 501 502 static __net_init int mirred_init_net(struct net *net) 503 { 504 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id); 505 506 return tc_action_net_init(net, tn, &act_mirred_ops); 507 } 508 509 static void __net_exit mirred_exit_net(struct list_head *net_list) 510 { 511 tc_action_net_exit(net_list, act_mirred_ops.net_id); 512 } 513 514 static struct pernet_operations mirred_net_ops = { 515 .init = mirred_init_net, 516 .exit_batch = mirred_exit_net, 517 .id = &act_mirred_ops.net_id, 518 .size = sizeof(struct tc_action_net), 519 }; 520 521 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 522 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 523 MODULE_LICENSE("GPL"); 524 525 static int __init mirred_init_module(void) 526 { 527 int err = register_netdevice_notifier(&mirred_device_notifier); 528 if (err) 529 return err; 530 531 pr_info("Mirror/redirect action on\n"); 532 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops); 533 if (err) 534 unregister_netdevice_notifier(&mirred_device_notifier); 535 536 return err; 537 } 538 539 static void __exit mirred_cleanup_module(void) 540 { 541 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); 542 unregister_netdevice_notifier(&mirred_device_notifier); 543 } 544 545 module_init(mirred_init_module); 546 module_exit(mirred_cleanup_module); 547