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