net/sched/act_mirred.c

   1 /*
   2  * net/sched/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 struct tcf_hashinfo mirred_hash_info;
  35
  36 static int tcf_mirred_release(struct tcf_mirred *m, int bind)
  37 {
  38         if (m) {
  39                 if (bind)
  40                         m->tcf_bindcnt--;
  41                 m->tcf_refcnt--;
  42                 if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  43                         list_del(&m->tcfm_list);
  44                         if (m->tcfm_dev)
  45                                 dev_put(m->tcfm_dev);
  46                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  47                         return 1;
  48                 }
  49         }
  50         return 0;
  51 }
  52
  53 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  54         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  55 };
  56
  57 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
  58                            struct nlattr *est, struct tc_action *a, int ovr,
  59                            int bind)
  60 {
  61         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  62         struct tc_mirred *parm;
  63         struct tcf_mirred *m;
  64         struct tcf_common *pc;
  65         struct net_device *dev;
  66         int ret, ok_push = 0;
  67
  68         if (nla == NULL)
  69                 return -EINVAL;
  70         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  71         if (ret < 0)
  72                 return ret;
  73         if (tb[TCA_MIRRED_PARMS] == NULL)
  74                 return -EINVAL;
  75         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  76         switch (parm->eaction) {
  77         case TCA_EGRESS_MIRROR:
  78         case TCA_EGRESS_REDIR:
  79                 break;
  80         default:
  81                 return -EINVAL;
  82         }
  83         if (parm->ifindex) {
  84                 dev = __dev_get_by_index(net, parm->ifindex);
  85                 if (dev == NULL)
  86                         return -ENODEV;
  87                 switch (dev->type) {
  88                 case ARPHRD_TUNNEL:
  89                 case ARPHRD_TUNNEL6:
  90                 case ARPHRD_SIT:
  91                 case ARPHRD_IPGRE:
  92                 case ARPHRD_VOID:
  93                 case ARPHRD_NONE:
  94                         ok_push = 0;
  95                         break;
  96                 default:
  97                         ok_push = 1;
  98                         break;
  99                 }
 100         } else {
 101                 dev = NULL;
 102         }
 103
 104         pc = tcf_hash_check(parm->index, a, bind);
 105         if (!pc) {
 106                 if (dev == NULL)
 107                         return -EINVAL;
 108                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind);
 109                 if (IS_ERR(pc))
 110                         return PTR_ERR(pc);
 111                 ret = ACT_P_CREATED;
 112         } else {
 113                 if (!ovr) {
 114                         tcf_mirred_release(to_mirred(pc), bind);
 115                         return -EEXIST;
 116                 }
 117         }
 118         m = to_mirred(pc);
 119
 120         spin_lock_bh(&m->tcf_lock);
 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(m->tcfm_dev);
 127                 dev_hold(dev);
 128                 m->tcfm_dev = dev;
 129                 m->tcfm_ok_push = ok_push;
 130         }
 131         spin_unlock_bh(&m->tcf_lock);
 132         if (ret == ACT_P_CREATED) {
 133                 list_add(&m->tcfm_list, &mirred_list);
 134                 tcf_hash_insert(pc, a->ops->hinfo);
 135         }
 136
 137         return ret;
 138 }
 139
 140 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 141 {
 142         struct tcf_mirred *m = a->priv;
 143
 144         if (m)
 145                 return tcf_mirred_release(m, bind);
 146         return 0;
 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         u32 at;
 156         int retval, err = 1;
 157
 158         spin_lock(&m->tcf_lock);
 159         m->tcf_tm.lastuse = jiffies;
 160         bstats_update(&m->tcf_bstats, skb);
 161
 162         dev = m->tcfm_dev;
 163         if (!dev) {
 164                 printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
 165                 goto out;
 166         }
 167
 168         if (!(dev->flags & IFF_UP)) {
 169                 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 170                                        dev->name);
 171                 goto out;
 172         }
 173
 174         at = G_TC_AT(skb->tc_verd);
 175         skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
 176         if (skb2 == NULL)
 177                 goto out;
 178
 179         if (!(at & AT_EGRESS)) {
 180                 if (m->tcfm_ok_push)
 181                         skb_push(skb2, skb2->dev->hard_header_len);
 182         }
 183
 184         /* mirror is always swallowed */
 185         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 186                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 187
 188         skb2->skb_iif = skb->dev->ifindex;
 189         skb2->dev = dev;
 190         err = dev_queue_xmit(skb2);
 191
 192 out:
 193         if (err) {
 194                 m->tcf_qstats.overlimits++;
 195                 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 196                         retval = TC_ACT_SHOT;
 197                 else
 198                         retval = m->tcf_action;
 199         } else
 200                 retval = m->tcf_action;
 201         spin_unlock(&m->tcf_lock);
 202
 203         return retval;
 204 }
 205
 206 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 207 {
 208         unsigned char *b = skb_tail_pointer(skb);
 209         struct tcf_mirred *m = a->priv;
 210         struct tc_mirred opt = {
 211                 .index   = m->tcf_index,
 212                 .action  = m->tcf_action,
 213                 .refcnt  = m->tcf_refcnt - ref,
 214                 .bindcnt = m->tcf_bindcnt - bind,
 215                 .eaction = m->tcfm_eaction,
 216                 .ifindex = m->tcfm_ifindex,
 217         };
 218         struct tcf_t t;
 219
 220         if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 221                 goto nla_put_failure;
 222         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 223         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 224         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 225         if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
 226                 goto nla_put_failure;
 227         return skb->len;
 228
 229 nla_put_failure:
 230         nlmsg_trim(skb, b);
 231         return -1;
 232 }
 233
 234 static int mirred_device_event(struct notifier_block *unused,
 235                                unsigned long event, void *ptr)
 236 {
 237         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 238         struct tcf_mirred *m;
 239
 240         if (event == NETDEV_UNREGISTER)
 241                 list_for_each_entry(m, &mirred_list, tcfm_list) {
 242                         if (m->tcfm_dev == dev) {
 243                                 dev_put(dev);
 244                                 m->tcfm_dev = NULL;
 245                         }
 246                 }
 247
 248         return NOTIFY_DONE;
 249 }
 250
 251 static struct notifier_block mirred_device_notifier = {
 252         .notifier_call = mirred_device_event,
 253 };
 254
 255 static struct tc_action_ops act_mirred_ops = {
 256         .kind           =       "mirred",
 257         .hinfo          =       &mirred_hash_info,
 258         .type           =       TCA_ACT_MIRRED,
 259         .owner          =       THIS_MODULE,
 260         .act            =       tcf_mirred,
 261         .dump           =       tcf_mirred_dump,
 262         .cleanup        =       tcf_mirred_cleanup,
 263         .init           =       tcf_mirred_init,
 264 };
 265
 266 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 267 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 268 MODULE_LICENSE("GPL");
 269
 270 static int __init mirred_init_module(void)
 271 {
 272         int err = register_netdevice_notifier(&mirred_device_notifier);
 273         if (err)
 274                 return err;
 275
 276         err = tcf_hashinfo_init(&mirred_hash_info, MIRRED_TAB_MASK);
 277         if (err) {
 278                 unregister_netdevice_notifier(&mirred_device_notifier);
 279                 return err;
 280         }
 281         pr_info("Mirror/redirect action on\n");
 282         return tcf_register_action(&act_mirred_ops);
 283 }
 284
 285 static void __exit mirred_cleanup_module(void)
 286 {
 287         tcf_unregister_action(&act_mirred_ops);
 288         tcf_hashinfo_destroy(&mirred_hash_info);
 289         unregister_netdevice_notifier(&mirred_device_notifier);
 290 }
 291
 292 module_init(mirred_init_module);
 293 module_exit(mirred_cleanup_module);