1 /* 2 * net/sched/act_mirred.c packet mirroring and redirect actions 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Jamal Hadi Salim (2002-4) 10 * 11 * TODO: Add ingress support (and socket redirect support) 12 * 13 */ 14 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/string.h> 18 #include <linux/errno.h> 19 #include <linux/skbuff.h> 20 #include <linux/rtnetlink.h> 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/gfp.h> 24 #include <linux/if_arp.h> 25 #include <net/net_namespace.h> 26 #include <net/netlink.h> 27 #include <net/pkt_sched.h> 28 #include <linux/tc_act/tc_mirred.h> 29 #include <net/tc_act/tc_mirred.h> 30 31 #include <linux/if_arp.h> 32 33 #define MIRRED_TAB_MASK 7 34 static LIST_HEAD(mirred_list); 35 static DEFINE_SPINLOCK(mirred_list_lock); 36 37 static bool tcf_mirred_is_act_redirect(int action) 38 { 39 return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR; 40 } 41 42 static u32 tcf_mirred_act_direction(int action) 43 { 44 switch (action) { 45 case TCA_EGRESS_REDIR: 46 case TCA_EGRESS_MIRROR: 47 return AT_EGRESS; 48 case TCA_INGRESS_REDIR: 49 case TCA_INGRESS_MIRROR: 50 return AT_INGRESS; 51 default: 52 BUG(); 53 } 54 } 55 56 static void tcf_mirred_release(struct tc_action *a, int bind) 57 { 58 struct tcf_mirred *m = to_mirred(a); 59 struct net_device *dev; 60 61 /* We could be called either in a RCU callback or with RTNL lock held. */ 62 spin_lock_bh(&mirred_list_lock); 63 list_del(&m->tcfm_list); 64 dev = rcu_dereference_protected(m->tcfm_dev, 1); 65 if (dev) 66 dev_put(dev); 67 spin_unlock_bh(&mirred_list_lock); 68 } 69 70 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 71 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 72 }; 73 74 static unsigned int mirred_net_id; 75 static struct tc_action_ops act_mirred_ops; 76 77 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 78 struct nlattr *est, struct tc_action **a, int ovr, 79 int bind) 80 { 81 struct tc_action_net *tn = net_generic(net, mirred_net_id); 82 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 83 bool mac_header_xmit = false; 84 struct tc_mirred *parm; 85 struct tcf_mirred *m; 86 struct net_device *dev; 87 bool exists = false; 88 int ret; 89 90 if (nla == NULL) 91 return -EINVAL; 92 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 93 if (ret < 0) 94 return ret; 95 if (tb[TCA_MIRRED_PARMS] == NULL) 96 return -EINVAL; 97 parm = nla_data(tb[TCA_MIRRED_PARMS]); 98 99 exists = tcf_hash_check(tn, parm->index, a, bind); 100 if (exists && bind) 101 return 0; 102 103 switch (parm->eaction) { 104 case TCA_EGRESS_MIRROR: 105 case TCA_EGRESS_REDIR: 106 case TCA_INGRESS_REDIR: 107 case TCA_INGRESS_MIRROR: 108 break; 109 default: 110 if (exists) 111 tcf_hash_release(*a, bind); 112 return -EINVAL; 113 } 114 if (parm->ifindex) { 115 dev = __dev_get_by_index(net, parm->ifindex); 116 if (dev == NULL) { 117 if (exists) 118 tcf_hash_release(*a, bind); 119 return -ENODEV; 120 } 121 mac_header_xmit = dev_is_mac_header_xmit(dev); 122 } else { 123 dev = NULL; 124 } 125 126 if (!exists) { 127 if (dev == NULL) 128 return -EINVAL; 129 ret = tcf_hash_create(tn, parm->index, est, a, 130 &act_mirred_ops, bind, true); 131 if (ret) 132 return ret; 133 ret = ACT_P_CREATED; 134 } else { 135 tcf_hash_release(*a, bind); 136 if (!ovr) 137 return -EEXIST; 138 } 139 m = to_mirred(*a); 140 141 ASSERT_RTNL(); 142 m->tcf_action = parm->action; 143 m->tcfm_eaction = parm->eaction; 144 if (dev != NULL) { 145 m->tcfm_ifindex = parm->ifindex; 146 if (ret != ACT_P_CREATED) 147 dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); 148 dev_hold(dev); 149 rcu_assign_pointer(m->tcfm_dev, dev); 150 m->tcfm_mac_header_xmit = mac_header_xmit; 151 } 152 153 if (ret == ACT_P_CREATED) { 154 spin_lock_bh(&mirred_list_lock); 155 list_add(&m->tcfm_list, &mirred_list); 156 spin_unlock_bh(&mirred_list_lock); 157 tcf_hash_insert(tn, *a); 158 } 159 160 return ret; 161 } 162 163 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 164 struct tcf_result *res) 165 { 166 struct tcf_mirred *m = to_mirred(a); 167 bool m_mac_header_xmit; 168 struct net_device *dev; 169 struct sk_buff *skb2; 170 int retval, err = 0; 171 int m_eaction; 172 int mac_len; 173 u32 at; 174 175 tcf_lastuse_update(&m->tcf_tm); 176 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); 177 178 rcu_read_lock(); 179 m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit); 180 m_eaction = READ_ONCE(m->tcfm_eaction); 181 retval = READ_ONCE(m->tcf_action); 182 dev = rcu_dereference(m->tcfm_dev); 183 if (unlikely(!dev)) { 184 pr_notice_once("tc mirred: target device is gone\n"); 185 goto out; 186 } 187 188 if (unlikely(!(dev->flags & IFF_UP))) { 189 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 190 dev->name); 191 goto out; 192 } 193 194 at = G_TC_AT(skb->tc_verd); 195 skb2 = skb_clone(skb, GFP_ATOMIC); 196 if (!skb2) 197 goto out; 198 199 /* If action's target direction differs than filter's direction, 200 * and devices expect a mac header on xmit, then mac push/pull is 201 * needed. 202 */ 203 if (at != tcf_mirred_act_direction(m_eaction) && m_mac_header_xmit) { 204 if (at & AT_EGRESS) { 205 /* caught at egress, act ingress: pull mac */ 206 mac_len = skb_network_header(skb) - skb_mac_header(skb); 207 skb_pull_rcsum(skb2, mac_len); 208 } else { 209 /* caught at ingress, act egress: push mac */ 210 skb_push_rcsum(skb2, skb->mac_len); 211 } 212 } 213 214 /* mirror is always swallowed */ 215 if (tcf_mirred_is_act_redirect(m_eaction)) 216 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 217 218 skb2->skb_iif = skb->dev->ifindex; 219 skb2->dev = dev; 220 if (tcf_mirred_act_direction(m_eaction) & AT_EGRESS) 221 err = dev_queue_xmit(skb2); 222 else 223 err = netif_receive_skb(skb2); 224 225 if (err) { 226 out: 227 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); 228 if (tcf_mirred_is_act_redirect(m_eaction)) 229 retval = TC_ACT_SHOT; 230 } 231 rcu_read_unlock(); 232 233 return retval; 234 } 235 236 static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets, 237 u64 lastuse) 238 { 239 struct tcf_mirred *m = to_mirred(a); 240 struct tcf_t *tm = &m->tcf_tm; 241 242 _bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets); 243 tm->lastuse = lastuse; 244 } 245 246 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, 247 int ref) 248 { 249 unsigned char *b = skb_tail_pointer(skb); 250 struct tcf_mirred *m = to_mirred(a); 251 struct tc_mirred opt = { 252 .index = m->tcf_index, 253 .action = m->tcf_action, 254 .refcnt = m->tcf_refcnt - ref, 255 .bindcnt = m->tcf_bindcnt - bind, 256 .eaction = m->tcfm_eaction, 257 .ifindex = m->tcfm_ifindex, 258 }; 259 struct tcf_t t; 260 261 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 262 goto nla_put_failure; 263 264 tcf_tm_dump(&t, &m->tcf_tm); 265 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) 266 goto nla_put_failure; 267 return skb->len; 268 269 nla_put_failure: 270 nlmsg_trim(skb, b); 271 return -1; 272 } 273 274 static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, 275 struct netlink_callback *cb, int type, 276 const struct tc_action_ops *ops) 277 { 278 struct tc_action_net *tn = net_generic(net, mirred_net_id); 279 280 return tcf_generic_walker(tn, skb, cb, type, ops); 281 } 282 283 static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) 284 { 285 struct tc_action_net *tn = net_generic(net, mirred_net_id); 286 287 return tcf_hash_search(tn, a, index); 288 } 289 290 static int mirred_device_event(struct notifier_block *unused, 291 unsigned long event, void *ptr) 292 { 293 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 294 struct tcf_mirred *m; 295 296 ASSERT_RTNL(); 297 if (event == NETDEV_UNREGISTER) { 298 spin_lock_bh(&mirred_list_lock); 299 list_for_each_entry(m, &mirred_list, tcfm_list) { 300 if (rcu_access_pointer(m->tcfm_dev) == dev) { 301 dev_put(dev); 302 /* Note : no rcu grace period necessary, as 303 * net_device are already rcu protected. 304 */ 305 RCU_INIT_POINTER(m->tcfm_dev, NULL); 306 } 307 } 308 spin_unlock_bh(&mirred_list_lock); 309 } 310 311 return NOTIFY_DONE; 312 } 313 314 static struct notifier_block mirred_device_notifier = { 315 .notifier_call = mirred_device_event, 316 }; 317 318 static int tcf_mirred_device(const struct tc_action *a, struct net *net, 319 struct net_device **mirred_dev) 320 { 321 int ifindex = tcf_mirred_ifindex(a); 322 323 *mirred_dev = __dev_get_by_index(net, ifindex); 324 if (!*mirred_dev) 325 return -EINVAL; 326 return 0; 327 } 328 329 static struct tc_action_ops act_mirred_ops = { 330 .kind = "mirred", 331 .type = TCA_ACT_MIRRED, 332 .owner = THIS_MODULE, 333 .act = tcf_mirred, 334 .stats_update = tcf_stats_update, 335 .dump = tcf_mirred_dump, 336 .cleanup = tcf_mirred_release, 337 .init = tcf_mirred_init, 338 .walk = tcf_mirred_walker, 339 .lookup = tcf_mirred_search, 340 .size = sizeof(struct tcf_mirred), 341 .get_dev = tcf_mirred_device, 342 }; 343 344 static __net_init int mirred_init_net(struct net *net) 345 { 346 struct tc_action_net *tn = net_generic(net, mirred_net_id); 347 348 return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); 349 } 350 351 static void __net_exit mirred_exit_net(struct net *net) 352 { 353 struct tc_action_net *tn = net_generic(net, mirred_net_id); 354 355 tc_action_net_exit(tn); 356 } 357 358 static struct pernet_operations mirred_net_ops = { 359 .init = mirred_init_net, 360 .exit = mirred_exit_net, 361 .id = &mirred_net_id, 362 .size = sizeof(struct tc_action_net), 363 }; 364 365 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 366 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 367 MODULE_LICENSE("GPL"); 368 369 static int __init mirred_init_module(void) 370 { 371 int err = register_netdevice_notifier(&mirred_device_notifier); 372 if (err) 373 return err; 374 375 pr_info("Mirror/redirect action on\n"); 376 return tcf_register_action(&act_mirred_ops, &mirred_net_ops); 377 } 378 379 static void __exit mirred_cleanup_module(void) 380 { 381 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); 382 unregister_netdevice_notifier(&mirred_device_notifier); 383 } 384 385 module_init(mirred_init_module); 386 module_exit(mirred_cleanup_module); 387