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