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 <net/net_namespace.h> 25 #include <net/netlink.h> 26 #include <net/pkt_sched.h> 27 #include <linux/tc_act/tc_mirred.h> 28 #include <net/tc_act/tc_mirred.h> 29 30 #include <linux/if_arp.h> 31 32 #define MIRRED_TAB_MASK 7 33 static LIST_HEAD(mirred_list); 34 static DEFINE_SPINLOCK(mirred_list_lock); 35 36 static void tcf_mirred_release(struct tc_action *a, int bind) 37 { 38 struct tcf_mirred *m = to_mirred(a); 39 struct net_device *dev; 40 41 /* We could be called either in a RCU callback or with RTNL lock held. */ 42 spin_lock_bh(&mirred_list_lock); 43 list_del(&m->tcfm_list); 44 dev = rcu_dereference_protected(m->tcfm_dev, 1); 45 if (dev) 46 dev_put(dev); 47 spin_unlock_bh(&mirred_list_lock); 48 } 49 50 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { 51 [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, 52 }; 53 54 static int mirred_net_id; 55 static struct tc_action_ops act_mirred_ops; 56 57 static int tcf_mirred_init(struct net *net, struct nlattr *nla, 58 struct nlattr *est, struct tc_action **a, int ovr, 59 int bind) 60 { 61 struct tc_action_net *tn = net_generic(net, mirred_net_id); 62 struct nlattr *tb[TCA_MIRRED_MAX + 1]; 63 struct tc_mirred *parm; 64 struct tcf_mirred *m; 65 struct net_device *dev; 66 int ret, ok_push = 0; 67 bool exists = false; 68 69 if (nla == NULL) 70 return -EINVAL; 71 ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy); 72 if (ret < 0) 73 return ret; 74 if (tb[TCA_MIRRED_PARMS] == NULL) 75 return -EINVAL; 76 parm = nla_data(tb[TCA_MIRRED_PARMS]); 77 78 exists = tcf_hash_check(tn, parm->index, a, bind); 79 if (exists && bind) 80 return 0; 81 82 switch (parm->eaction) { 83 case TCA_EGRESS_MIRROR: 84 case TCA_EGRESS_REDIR: 85 break; 86 default: 87 if (exists) 88 tcf_hash_release(*a, bind); 89 return -EINVAL; 90 } 91 if (parm->ifindex) { 92 dev = __dev_get_by_index(net, parm->ifindex); 93 if (dev == NULL) { 94 if (exists) 95 tcf_hash_release(*a, bind); 96 return -ENODEV; 97 } 98 switch (dev->type) { 99 case ARPHRD_TUNNEL: 100 case ARPHRD_TUNNEL6: 101 case ARPHRD_SIT: 102 case ARPHRD_IPGRE: 103 case ARPHRD_VOID: 104 case ARPHRD_NONE: 105 ok_push = 0; 106 break; 107 default: 108 ok_push = 1; 109 break; 110 } 111 } else { 112 dev = NULL; 113 } 114 115 if (!exists) { 116 if (dev == NULL) 117 return -EINVAL; 118 ret = tcf_hash_create(tn, parm->index, est, a, 119 &act_mirred_ops, bind, true); 120 if (ret) 121 return ret; 122 ret = ACT_P_CREATED; 123 } else { 124 tcf_hash_release(*a, bind); 125 if (!ovr) 126 return -EEXIST; 127 } 128 m = to_mirred(*a); 129 130 ASSERT_RTNL(); 131 m->tcf_action = parm->action; 132 m->tcfm_eaction = parm->eaction; 133 if (dev != NULL) { 134 m->tcfm_ifindex = parm->ifindex; 135 if (ret != ACT_P_CREATED) 136 dev_put(rcu_dereference_protected(m->tcfm_dev, 1)); 137 dev_hold(dev); 138 rcu_assign_pointer(m->tcfm_dev, dev); 139 m->tcfm_ok_push = ok_push; 140 } 141 142 if (ret == ACT_P_CREATED) { 143 spin_lock_bh(&mirred_list_lock); 144 list_add(&m->tcfm_list, &mirred_list); 145 spin_unlock_bh(&mirred_list_lock); 146 tcf_hash_insert(tn, *a); 147 } 148 149 return ret; 150 } 151 152 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a, 153 struct tcf_result *res) 154 { 155 struct tcf_mirred *m = to_mirred(a); 156 struct net_device *dev; 157 struct sk_buff *skb2; 158 int retval, err; 159 u32 at; 160 161 tcf_lastuse_update(&m->tcf_tm); 162 bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb); 163 164 rcu_read_lock(); 165 retval = READ_ONCE(m->tcf_action); 166 dev = rcu_dereference(m->tcfm_dev); 167 if (unlikely(!dev)) { 168 pr_notice_once("tc mirred: target device is gone\n"); 169 goto out; 170 } 171 172 if (unlikely(!(dev->flags & IFF_UP))) { 173 net_notice_ratelimited("tc mirred to Houston: device %s is down\n", 174 dev->name); 175 goto out; 176 } 177 178 at = G_TC_AT(skb->tc_verd); 179 skb2 = skb_clone(skb, GFP_ATOMIC); 180 if (!skb2) 181 goto out; 182 183 if (!(at & AT_EGRESS)) { 184 if (m->tcfm_ok_push) 185 skb_push_rcsum(skb2, skb->mac_len); 186 } 187 188 /* mirror is always swallowed */ 189 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 190 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at); 191 192 skb2->skb_iif = skb->dev->ifindex; 193 skb2->dev = dev; 194 err = dev_queue_xmit(skb2); 195 196 if (err) { 197 out: 198 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats)); 199 if (m->tcfm_eaction != TCA_EGRESS_MIRROR) 200 retval = TC_ACT_SHOT; 201 } 202 rcu_read_unlock(); 203 204 return retval; 205 } 206 207 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 208 { 209 unsigned char *b = skb_tail_pointer(skb); 210 struct tcf_mirred *m = to_mirred(a); 211 struct tc_mirred opt = { 212 .index = m->tcf_index, 213 .action = m->tcf_action, 214 .refcnt = m->tcf_refcnt - ref, 215 .bindcnt = m->tcf_bindcnt - bind, 216 .eaction = m->tcfm_eaction, 217 .ifindex = m->tcfm_ifindex, 218 }; 219 struct tcf_t t; 220 221 if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt)) 222 goto nla_put_failure; 223 224 tcf_tm_dump(&t, &m->tcf_tm); 225 if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD)) 226 goto nla_put_failure; 227 return skb->len; 228 229 nla_put_failure: 230 nlmsg_trim(skb, b); 231 return -1; 232 } 233 234 static int tcf_mirred_walker(struct net *net, struct sk_buff *skb, 235 struct netlink_callback *cb, int type, 236 const struct tc_action_ops *ops) 237 { 238 struct tc_action_net *tn = net_generic(net, mirred_net_id); 239 240 return tcf_generic_walker(tn, skb, cb, type, ops); 241 } 242 243 static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index) 244 { 245 struct tc_action_net *tn = net_generic(net, mirred_net_id); 246 247 return tcf_hash_search(tn, a, index); 248 } 249 250 static int mirred_device_event(struct notifier_block *unused, 251 unsigned long event, void *ptr) 252 { 253 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 254 struct tcf_mirred *m; 255 256 ASSERT_RTNL(); 257 if (event == NETDEV_UNREGISTER) { 258 spin_lock_bh(&mirred_list_lock); 259 list_for_each_entry(m, &mirred_list, tcfm_list) { 260 if (rcu_access_pointer(m->tcfm_dev) == dev) { 261 dev_put(dev); 262 /* Note : no rcu grace period necessary, as 263 * net_device are already rcu protected. 264 */ 265 RCU_INIT_POINTER(m->tcfm_dev, NULL); 266 } 267 } 268 spin_unlock_bh(&mirred_list_lock); 269 } 270 271 return NOTIFY_DONE; 272 } 273 274 static struct notifier_block mirred_device_notifier = { 275 .notifier_call = mirred_device_event, 276 }; 277 278 static struct tc_action_ops act_mirred_ops = { 279 .kind = "mirred", 280 .type = TCA_ACT_MIRRED, 281 .owner = THIS_MODULE, 282 .act = tcf_mirred, 283 .dump = tcf_mirred_dump, 284 .cleanup = tcf_mirred_release, 285 .init = tcf_mirred_init, 286 .walk = tcf_mirred_walker, 287 .lookup = tcf_mirred_search, 288 .size = sizeof(struct tcf_mirred), 289 }; 290 291 static __net_init int mirred_init_net(struct net *net) 292 { 293 struct tc_action_net *tn = net_generic(net, mirred_net_id); 294 295 return tc_action_net_init(tn, &act_mirred_ops, MIRRED_TAB_MASK); 296 } 297 298 static void __net_exit mirred_exit_net(struct net *net) 299 { 300 struct tc_action_net *tn = net_generic(net, mirred_net_id); 301 302 tc_action_net_exit(tn); 303 } 304 305 static struct pernet_operations mirred_net_ops = { 306 .init = mirred_init_net, 307 .exit = mirred_exit_net, 308 .id = &mirred_net_id, 309 .size = sizeof(struct tc_action_net), 310 }; 311 312 MODULE_AUTHOR("Jamal Hadi Salim(2002)"); 313 MODULE_DESCRIPTION("Device Mirror/redirect actions"); 314 MODULE_LICENSE("GPL"); 315 316 static int __init mirred_init_module(void) 317 { 318 int err = register_netdevice_notifier(&mirred_device_notifier); 319 if (err) 320 return err; 321 322 pr_info("Mirror/redirect action on\n"); 323 return tcf_register_action(&act_mirred_ops, &mirred_net_ops); 324 } 325 326 static void __exit mirred_cleanup_module(void) 327 { 328 tcf_unregister_action(&act_mirred_ops, &mirred_net_ops); 329 unregister_netdevice_notifier(&mirred_device_notifier); 330 } 331 332 module_init(mirred_init_module); 333 module_exit(mirred_cleanup_module); 334