net/sched/act_mirred.c

   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);