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