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
  35 static void tcf_mirred_release(struct tc_action *a, int bind)
  36 {
  37         struct tcf_mirred *m = to_mirred(a);
  38         struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1);
  39
  40         list_del(&m->tcfm_list);
  41         if (dev)
  42                 dev_put(dev);
  43 }
  44
  45 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  46         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  47 };
  48
  49 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
  50                            struct nlattr *est, struct tc_action *a, int ovr,
  51                            int bind)
  52 {
  53         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  54         struct tc_mirred *parm;
  55         struct tcf_mirred *m;
  56         struct net_device *dev;
  57         int ret, ok_push = 0;
  58
  59         if (nla == NULL)
  60                 return -EINVAL;
  61         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  62         if (ret < 0)
  63                 return ret;
  64         if (tb[TCA_MIRRED_PARMS] == NULL)
  65                 return -EINVAL;
  66         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  67         switch (parm->eaction) {
  68         case TCA_EGRESS_MIRROR:
  69         case TCA_EGRESS_REDIR:
  70                 break;
  71         default:
  72                 return -EINVAL;
  73         }
  74         if (parm->ifindex) {
  75                 dev = __dev_get_by_index(net, parm->ifindex);
  76                 if (dev == NULL)
  77                         return -ENODEV;
  78                 switch (dev->type) {
  79                 case ARPHRD_TUNNEL:
  80                 case ARPHRD_TUNNEL6:
  81                 case ARPHRD_SIT:
  82                 case ARPHRD_IPGRE:
  83                 case ARPHRD_VOID:
  84                 case ARPHRD_NONE:
  85                         ok_push = 0;
  86                         break;
  87                 default:
  88                         ok_push = 1;
  89                         break;
  90                 }
  91         } else {
  92                 dev = NULL;
  93         }
  94
  95         if (!tcf_hash_check(parm->index, a, bind)) {
  96                 if (dev == NULL)
  97                         return -EINVAL;
  98                 ret = tcf_hash_create(parm->index, est, a, sizeof(*m),
  99                                       bind, true);
 100                 if (ret)
 101                         return ret;
 102                 ret = ACT_P_CREATED;
 103         } else {
 104                 if (!ovr) {
 105                         tcf_hash_release(a, bind);
 106                         return -EEXIST;
 107                 }
 108         }
 109         m = to_mirred(a);
 110
 111         ASSERT_RTNL();
 112         m->tcf_action = parm->action;
 113         m->tcfm_eaction = parm->eaction;
 114         if (dev != NULL) {
 115                 m->tcfm_ifindex = parm->ifindex;
 116                 if (ret != ACT_P_CREATED)
 117                         dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
 118                 dev_hold(dev);
 119                 rcu_assign_pointer(m->tcfm_dev, dev);
 120                 m->tcfm_ok_push = ok_push;
 121         }
 122
 123         if (ret == ACT_P_CREATED) {
 124                 list_add(&m->tcfm_list, &mirred_list);
 125                 tcf_hash_insert(a);
 126         }
 127
 128         return ret;
 129 }
 130
 131 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 132                       struct tcf_result *res)
 133 {
 134         struct tcf_mirred *m = a->priv;
 135         struct net_device *dev;
 136         struct sk_buff *skb2;
 137         int retval, err;
 138         u32 at;
 139
 140         tcf_lastuse_update(&m->tcf_tm);
 141
 142         bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
 143
 144         rcu_read_lock();
 145         retval = READ_ONCE(m->tcf_action);
 146         dev = rcu_dereference(m->tcfm_dev);
 147         if (unlikely(!dev)) {
 148                 pr_notice_once("tc mirred: target device is gone\n");
 149                 goto out;
 150         }
 151
 152         if (unlikely(!(dev->flags & IFF_UP))) {
 153                 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 154                                        dev->name);
 155                 goto out;
 156         }
 157
 158         at = G_TC_AT(skb->tc_verd);
 159         skb2 = skb_clone(skb, GFP_ATOMIC);
 160         if (!skb2)
 161                 goto out;
 162
 163         if (!(at & AT_EGRESS)) {
 164                 if (m->tcfm_ok_push)
 165                         skb_push(skb2, skb->mac_len);
 166         }
 167
 168         /* mirror is always swallowed */
 169         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 170                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 171
 172         skb2->skb_iif = skb->dev->ifindex;
 173         skb2->dev = dev;
 174         err = dev_queue_xmit(skb2);
 175
 176         if (err) {
 177 out:
 178                 qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
 179                 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 180                         retval = TC_ACT_SHOT;
 181         }
 182         rcu_read_unlock();
 183
 184         return retval;
 185 }
 186
 187 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 188 {
 189         unsigned char *b = skb_tail_pointer(skb);
 190         struct tcf_mirred *m = a->priv;
 191         struct tc_mirred opt = {
 192                 .index   = m->tcf_index,
 193                 .action  = m->tcf_action,
 194                 .refcnt  = m->tcf_refcnt - ref,
 195                 .bindcnt = m->tcf_bindcnt - bind,
 196                 .eaction = m->tcfm_eaction,
 197                 .ifindex = m->tcfm_ifindex,
 198         };
 199         struct tcf_t t;
 200
 201         if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 202                 goto nla_put_failure;
 203         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 204         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 205         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 206         if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
 207                 goto nla_put_failure;
 208         return skb->len;
 209
 210 nla_put_failure:
 211         nlmsg_trim(skb, b);
 212         return -1;
 213 }
 214
 215 static int mirred_device_event(struct notifier_block *unused,
 216                                unsigned long event, void *ptr)
 217 {
 218         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 219         struct tcf_mirred *m;
 220
 221         ASSERT_RTNL();
 222         if (event == NETDEV_UNREGISTER)
 223                 list_for_each_entry(m, &mirred_list, tcfm_list) {
 224                         if (rcu_access_pointer(m->tcfm_dev) == dev) {
 225                                 dev_put(dev);
 226                                 /* Note : no rcu grace period necessary, as
 227                                  * net_device are already rcu protected.
 228                                  */
 229                                 RCU_INIT_POINTER(m->tcfm_dev, NULL);
 230                         }
 231                 }
 232
 233         return NOTIFY_DONE;
 234 }
 235
 236 static struct notifier_block mirred_device_notifier = {
 237         .notifier_call = mirred_device_event,
 238 };
 239
 240 static struct tc_action_ops act_mirred_ops = {
 241         .kind           =       "mirred",
 242         .type           =       TCA_ACT_MIRRED,
 243         .owner          =       THIS_MODULE,
 244         .act            =       tcf_mirred,
 245         .dump           =       tcf_mirred_dump,
 246         .cleanup        =       tcf_mirred_release,
 247         .init           =       tcf_mirred_init,
 248 };
 249
 250 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 251 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 252 MODULE_LICENSE("GPL");
 253
 254 static int __init mirred_init_module(void)
 255 {
 256         int err = register_netdevice_notifier(&mirred_device_notifier);
 257         if (err)
 258                 return err;
 259
 260         pr_info("Mirror/redirect action on\n");
 261         return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
 262 }
 263
 264 static void __exit mirred_cleanup_module(void)
 265 {
 266         tcf_unregister_action(&act_mirred_ops);
 267         unregister_netdevice_notifier(&mirred_device_notifier);
 268 }
 269
 270 module_init(mirred_init_module);
 271 module_exit(mirred_cleanup_module);