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