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 28 static LIST_HEAD(mirred_list); 29 static DEFINE_SPINLOCK(mirred_list_lock); 30 31 #define MIRRED_RECURSION_LIMIT 4 32 static DEFINE_PER_CPU(unsigned int, mirred_rec_level); 33 34 static bool tcf_mirred_is_act_redirect(int action) 35 { 36 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR; 37 } 38 39 static bool tcf_mirred_act_wants_ingress(int action) 40 { 41 switch (action) { 42 case TCA_EGRESS_REDIR: 43 case TCA_EGRESS_MIRROR: 44 return false; 45 case TCA_INGRESS_REDIR: 46 case TCA_INGRESS_MIRROR: 47 return true; 48 default: 49 BUG(); 50 } 51 } 52 53 static bool tcf_mirred_can_reinsert(int action) 54 { 55 switch (action) { 56 case TC_ACT_SHOT: 57 case TC_ACT_STOLEN: 58 case TC_ACT_QUEUED: 59 case TC_ACT_TRAP: 60 return true; 61 } 62 return false; 63 } 64 65 static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m) 66 { 67 return rcu_dereference_protected(m->tcfm_dev, 68 lockdep_is_held(&m->tcf_lock)); 69 } 70 71 static void tcf_mirred_release(struct tc_action *a) 72 { 73 struct tcf_mirred *m = to_mirred(a); 74 struct net_device *dev; 75 76 spin_lock(&mirred_list_lock); 77 list_del(&m->tcfm_list); 78 spin_unlock(&mirred_list_lock); 79 80 /* last reference to action, no need to lock */ 81 dev = rcu_dereference_protected(m->tcfm_dev, 1); 82 netdev_put(dev, &m->tcfm_dev_tracker); 83 } 84 85 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 86 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 87 }; 88 89 static struct tc_action_ops act_mirred_ops; 90 91 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 92 struct nlattr *est, struct tc_action **a, 93 struct tcf_proto *tp, 94 u32 flags, struct netlink_ext_ack *extack) 95 { 96 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id); 97 bool bind = flags & TCA_ACT_FLAGS_BIND; 98 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 99 struct tcf_chain *goto_ch = NULL; 100 bool mac_header_xmit = false; 101 struct tc_mirred *parm; 102 struct tcf_mirred *m; 103 bool exists = false; 104 int ret, err; 105 u32 index; 106 107 if (!nla) { 108 NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed"); 109 return -EINVAL; 110 } 111 ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla, 112 mirred_policy, extack); 113 if (ret < 0) 114 return ret; 115 if (!tb[TCA_MIRRED_PARMS]) { 116 NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters"); 117 return -EINVAL; 118 } 119 parm = nla_data(tb[TCA_MIRRED_PARMS]); 120 index = parm->index; 121 err = tcf_idr_check_alloc(tn, &index, a, bind); 122 if (err < 0) 123 return err; 124 exists = err; 125 if (exists && bind) 126 return 0; 127 128 switch (parm->eaction) { 129 case TCA_EGRESS_MIRROR: 130 case TCA_EGRESS_REDIR: 131 case TCA_INGRESS_REDIR: 132 case TCA_INGRESS_MIRROR: 133 break; 134 default: 135 if (exists) 136 tcf_idr_release(*a, bind); 137 else 138 tcf_idr_cleanup(tn, index); 139 NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option"); 140 return -EINVAL; 141 } 142 143 if (!exists) { 144 if (!parm->ifindex) { 145 tcf_idr_cleanup(tn, index); 146 NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist"); 147 return -EINVAL; 148 } 149 ret = tcf_idr_create_from_flags(tn, index, est, a, 150 &act_mirred_ops, bind, flags); 151 if (ret) { 152 tcf_idr_cleanup(tn, index); 153 return ret; 154 } 155 ret = ACT_P_CREATED; 156 } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 157 tcf_idr_release(*a, bind); 158 return -EEXIST; 159 } 160 161 m = to_mirred(*a); 162 if (ret == ACT_P_CREATED) 163 INIT_LIST_HEAD(&m->tcfm_list); 164 165 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 166 if (err < 0) 167 goto release_idr; 168 169 spin_lock_bh(&m->tcf_lock); 170 171 if (parm->ifindex) { 172 struct net_device *odev, *ndev; 173 174 ndev = dev_get_by_index(net, parm->ifindex); 175 if (!ndev) { 176 spin_unlock_bh(&m->tcf_lock); 177 err = -ENODEV; 178 goto put_chain; 179 } 180 mac_header_xmit = dev_is_mac_header_xmit(ndev); 181 odev = rcu_replace_pointer(m->tcfm_dev, ndev, 182 lockdep_is_held(&m->tcf_lock)); 183 netdev_put(odev, &m->tcfm_dev_tracker); 184 netdev_tracker_alloc(ndev, &m->tcfm_dev_tracker, GFP_ATOMIC); 185 m->tcfm_mac_header_xmit = mac_header_xmit; 186 } 187 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch); 188 m->tcfm_eaction = parm->eaction; 189 spin_unlock_bh(&m->tcf_lock); 190 if (goto_ch) 191 tcf_chain_put_by_act(goto_ch); 192 193 if (ret == ACT_P_CREATED) { 194 spin_lock(&mirred_list_lock); 195 list_add(&m->tcfm_list, &mirred_list); 196 spin_unlock(&mirred_list_lock); 197 } 198 199 return ret; 200 put_chain: 201 if (goto_ch) 202 tcf_chain_put_by_act(goto_ch); 203 release_idr: 204 tcf_idr_release(*a, bind); 205 return err; 206 } 207 208 static int tcf_mirred_forward(bool want_ingress, struct sk_buff *skb) 209 { 210 int err; 211 212 if (!want_ingress) 213 err = tcf_dev_queue_xmit(skb, dev_queue_xmit); 214 else 215 err = netif_receive_skb(skb); 216 217 return err; 218 } 219 220 static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a, 221 struct tcf_result *res) 222 { 223 struct tcf_mirred *m = to_mirred(a); 224 struct sk_buff *skb2 = skb; 225 bool m_mac_header_xmit; 226 struct net_device *dev; 227 unsigned int rec_level; 228 int retval, err = 0; 229 bool use_reinsert; 230 bool want_ingress; 231 bool is_redirect; 232 bool expects_nh; 233 bool at_ingress; 234 int m_eaction; 235 int mac_len; 236 bool at_nh; 237 238 rec_level = __this_cpu_inc_return(mirred_rec_level); 239 if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) { 240 net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n", 241 netdev_name(skb->dev)); 242 __this_cpu_dec(mirred_rec_level); 243 return TC_ACT_SHOT; 244 } 245 246 tcf_lastuse_update(&m->tcf_tm); 247 tcf_action_update_bstats(&m->common, skb); 248 249 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); 250 m_eaction = READ_ONCE(m->tcfm_eaction); 251 retval = READ_ONCE(m->tcf_action); 252 dev = rcu_dereference_bh(m->tcfm_dev); 253 if (unlikely(!dev)) { 254 pr_notice_once("tc mirred: target device is gone\n"); 255 goto out; 256 } 257 258 if (unlikely(!(dev->flags & IFF_UP))) { 259 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 260 dev->name); 261 goto out; 262 } 263 264 /* we could easily avoid the clone only if called by ingress and clsact; 265 * since we can't easily detect the clsact caller, skip clone only for 266 * ingress - that covers the TC S/W datapath. 267 */ 268 is_redirect = tcf_mirred_is_act_redirect(m_eaction); 269 at_ingress = skb_at_tc_ingress(skb); 270 use_reinsert = at_ingress && is_redirect && 271 tcf_mirred_can_reinsert(retval); 272 if (!use_reinsert) { 273 skb2 = skb_clone(skb, GFP_ATOMIC); 274 if (!skb2) 275 goto out; 276 } 277 278 want_ingress = tcf_mirred_act_wants_ingress(m_eaction); 279 280 /* All mirred/redirected skbs should clear previous ct info */ 281 nf_reset_ct(skb2); 282 if (want_ingress && !at_ingress) /* drop dst for egress -> ingress */ 283 skb_dst_drop(skb2); 284 285 expects_nh = want_ingress || !m_mac_header_xmit; 286 at_nh = skb->data == skb_network_header(skb); 287 if (at_nh != expects_nh) { 288 mac_len = skb_at_tc_ingress(skb) ? skb->mac_len : 289 skb_network_header(skb) - skb_mac_header(skb); 290 if (expects_nh) { 291 /* target device/action expect data at nh */ 292 skb_pull_rcsum(skb2, mac_len); 293 } else { 294 /* target device/action expect data at mac */ 295 skb_push_rcsum(skb2, mac_len); 296 } 297 } 298 299 skb2->skb_iif = skb->dev->ifindex; 300 skb2->dev = dev; 301 302 /* mirror is always swallowed */ 303 if (is_redirect) { 304 skb_set_redirected(skb2, skb2->tc_at_ingress); 305 306 /* let's the caller reinsert the packet, if possible */ 307 if (use_reinsert) { 308 res->ingress = want_ingress; 309 err = tcf_mirred_forward(res->ingress, skb); 310 if (err) 311 tcf_action_inc_overlimit_qstats(&m->common); 312 __this_cpu_dec(mirred_rec_level); 313 return TC_ACT_CONSUMED; 314 } 315 } 316 317 err = tcf_mirred_forward(want_ingress, skb2); 318 if (err) { 319 out: 320 tcf_action_inc_overlimit_qstats(&m->common); 321 if (tcf_mirred_is_act_redirect(m_eaction)) 322 retval = TC_ACT_SHOT; 323 } 324 __this_cpu_dec(mirred_rec_level); 325 326 return retval; 327 } 328 329 static void tcf_stats_update(struct tc_action *a, u64 bytes, u64 packets, 330 u64 drops, u64 lastuse, bool hw) 331 { 332 struct tcf_mirred *m = to_mirred(a); 333 struct tcf_t *tm = &m->tcf_tm; 334 335 tcf_action_update_stats(a, bytes, packets, drops, hw); 336 tm->lastuse = max_t(u64, tm->lastuse, lastuse); 337 } 338 339 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, 340 int ref) 341 { 342 unsigned char *b = skb_tail_pointer(skb); 343 struct tcf_mirred *m = to_mirred(a); 344 struct tc_mirred opt = { 345 .index = m->tcf_index, 346 .refcnt = refcount_read(&m->tcf_refcnt) - ref, 347 .bindcnt = atomic_read(&m->tcf_bindcnt) - bind, 348 }; 349 struct net_device *dev; 350 struct tcf_t t; 351 352 spin_lock_bh(&m->tcf_lock); 353 opt.action = m->tcf_action; 354 opt.eaction = m->tcfm_eaction; 355 dev = tcf_mirred_dev_dereference(m); 356 if (dev) 357 opt.ifindex = dev->ifindex; 358 359 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 360 goto nla_put_failure; 361 362 tcf_tm_dump(&t, &m->tcf_tm); 363 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) 364 goto nla_put_failure; 365 spin_unlock_bh(&m->tcf_lock); 366 367 return skb->len; 368 369 nla_put_failure: 370 spin_unlock_bh(&m->tcf_lock); 371 nlmsg_trim(skb, b); 372 return -1; 373 } 374 375 static int mirred_device_event(struct notifier_block *unused, 376 unsigned long event, void *ptr) 377 { 378 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 379 struct tcf_mirred *m; 380 381 ASSERT_RTNL(); 382 if (event == NETDEV_UNREGISTER) { 383 spin_lock(&mirred_list_lock); 384 list_for_each_entry(m, &mirred_list, tcfm_list) { 385 spin_lock_bh(&m->tcf_lock); 386 if (tcf_mirred_dev_dereference(m) == dev) { 387 netdev_put(dev, &m->tcfm_dev_tracker); 388 /* Note : no rcu grace period necessary, as 389 * net_device are already rcu protected. 390 */ 391 RCU_INIT_POINTER(m->tcfm_dev, NULL); 392 } 393 spin_unlock_bh(&m->tcf_lock); 394 } 395 spin_unlock(&mirred_list_lock); 396 } 397 398 return NOTIFY_DONE; 399 } 400 401 static struct notifier_block mirred_device_notifier = { 402 .notifier_call = mirred_device_event, 403 }; 404 405 static void tcf_mirred_dev_put(void *priv) 406 { 407 struct net_device *dev = priv; 408 409 dev_put(dev); 410 } 411 412 static struct net_device * 413 tcf_mirred_get_dev(const struct tc_action *a, 414 tc_action_priv_destructor *destructor) 415 { 416 struct tcf_mirred *m = to_mirred(a); 417 struct net_device *dev; 418 419 rcu_read_lock(); 420 dev = rcu_dereference(m->tcfm_dev); 421 if (dev) { 422 dev_hold(dev); 423 *destructor = tcf_mirred_dev_put; 424 } 425 rcu_read_unlock(); 426 427 return dev; 428 } 429 430 static size_t tcf_mirred_get_fill_size(const struct tc_action *act) 431 { 432 return nla_total_size(sizeof(struct tc_mirred)); 433 } 434 435 static void tcf_offload_mirred_get_dev(struct flow_action_entry *entry, 436 const struct tc_action *act) 437 { 438 entry->dev = act->ops->get_dev(act, &entry->destructor); 439 if (!entry->dev) 440 return; 441 entry->destructor_priv = entry->dev; 442 } 443 444 static int tcf_mirred_offload_act_setup(struct tc_action *act, void *entry_data, 445 u32 *index_inc, bool bind, 446 struct netlink_ext_ack *extack) 447 { 448 if (bind) { 449 struct flow_action_entry *entry = entry_data; 450 451 if (is_tcf_mirred_egress_redirect(act)) { 452 entry->id = FLOW_ACTION_REDIRECT; 453 tcf_offload_mirred_get_dev(entry, act); 454 } else if (is_tcf_mirred_egress_mirror(act)) { 455 entry->id = FLOW_ACTION_MIRRED; 456 tcf_offload_mirred_get_dev(entry, act); 457 } else if (is_tcf_mirred_ingress_redirect(act)) { 458 entry->id = FLOW_ACTION_REDIRECT_INGRESS; 459 tcf_offload_mirred_get_dev(entry, act); 460 } else if (is_tcf_mirred_ingress_mirror(act)) { 461 entry->id = FLOW_ACTION_MIRRED_INGRESS; 462 tcf_offload_mirred_get_dev(entry, act); 463 } else { 464 NL_SET_ERR_MSG_MOD(extack, "Unsupported mirred offload"); 465 return -EOPNOTSUPP; 466 } 467 *index_inc = 1; 468 } else { 469 struct flow_offload_action *fl_action = entry_data; 470 471 if (is_tcf_mirred_egress_redirect(act)) 472 fl_action->id = FLOW_ACTION_REDIRECT; 473 else if (is_tcf_mirred_egress_mirror(act)) 474 fl_action->id = FLOW_ACTION_MIRRED; 475 else if (is_tcf_mirred_ingress_redirect(act)) 476 fl_action->id = FLOW_ACTION_REDIRECT_INGRESS; 477 else if (is_tcf_mirred_ingress_mirror(act)) 478 fl_action->id = FLOW_ACTION_MIRRED_INGRESS; 479 else 480 return -EOPNOTSUPP; 481 } 482 483 return 0; 484 } 485 486 static struct tc_action_ops act_mirred_ops = { 487 .kind = "mirred", 488 .id = TCA_ID_MIRRED, 489 .owner = THIS_MODULE, 490 .act = tcf_mirred_act, 491 .stats_update = tcf_stats_update, 492 .dump = tcf_mirred_dump, 493 .cleanup = tcf_mirred_release, 494 .init = tcf_mirred_init, 495 .get_fill_size = tcf_mirred_get_fill_size, 496 .offload_act_setup = tcf_mirred_offload_act_setup, 497 .size = sizeof(struct tcf_mirred), 498 .get_dev = tcf_mirred_get_dev, 499 }; 500 501 static __net_init int mirred_init_net(struct net *net) 502 { 503 struct tc_action_net *tn = net_generic(net, act_mirred_ops.net_id); 504 505 return tc_action_net_init(net, tn, &act_mirred_ops); 506 } 507 508 static void __net_exit mirred_exit_net(struct list_head *net_list) 509 { 510 tc_action_net_exit(net_list, act_mirred_ops.net_id); 511 } 512 513 static struct pernet_operations mirred_net_ops = { 514 .init = mirred_init_net, 515 .exit_batch = mirred_exit_net, 516 .id = &act_mirred_ops.net_id, 517 .size = sizeof(struct tc_action_net), 518 }; 519 520 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 521 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 522 MODULE_LICENSE("GPL"); 523 524 static int __init mirred_init_module(void) 525 { 526 int err = register_netdevice_notifier(&mirred_device_notifier); 527 if (err) 528 return err; 529 530 pr_info("Mirror/redirect action on\n"); 531 err = tcf_register_action(&act_mirred_ops, &mirred_net_ops); 532 if (err) 533 unregister_netdevice_notifier(&mirred_device_notifier); 534 535 return err; 536 } 537 538 static void __exit mirred_cleanup_module(void) 539 { 540 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); 541 unregister_netdevice_notifier(&mirred_device_notifier); 542 } 543 544 module_init(mirred_init_module); 545 module_exit(mirred_cleanup_module); 546