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 u32 mirred_idx_gen;
  34 static LIST_HEAD(mirred_list);
  35 static struct tcf_hashinfo mirred_hash_info;
  36
  37 static int tcf_mirred_release(struct tcf_mirred *m, int bind)
  38 {
  39         if (m) {
  40                 if (bind)
  41                         m->tcf_bindcnt--;
  42                 m->tcf_refcnt--;
  43                 if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  44                         list_del(&m->tcfm_list);
  45                         if (m->tcfm_dev)
  46                                 dev_put(m->tcfm_dev);
  47                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  48                         return 1;
  49                 }
  50         }
  51         return 0;
  52 }
  53
  54 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  55         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  56 };
  57
  58 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
  59                            struct nlattr *est, struct tc_action *a, int ovr,
  60                            int bind)
  61 {
  62         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  63         struct tc_mirred *parm;
  64         struct tcf_mirred *m;
  65         struct tcf_common *pc;
  66         struct net_device *dev;
  67         int ret, ok_push = 0;
  68
  69         if (nla == NULL)
  70                 return -EINVAL;
  71         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  72         if (ret < 0)
  73                 return ret;
  74         if (tb[TCA_MIRRED_PARMS] == NULL)
  75                 return -EINVAL;
  76         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  77         switch (parm->eaction) {
  78         case TCA_EGRESS_MIRROR:
  79         case TCA_EGRESS_REDIR:
  80                 break;
  81         default:
  82                 return -EINVAL;
  83         }
  84         if (parm->ifindex) {
  85                 dev = __dev_get_by_index(net, parm->ifindex);
  86                 if (dev == NULL)
  87                         return -ENODEV;
  88                 switch (dev->type) {
  89                 case ARPHRD_TUNNEL:
  90                 case ARPHRD_TUNNEL6:
  91                 case ARPHRD_SIT:
  92                 case ARPHRD_IPGRE:
  93                 case ARPHRD_VOID:
  94                 case ARPHRD_NONE:
  95                         ok_push = 0;
  96                         break;
  97                 default:
  98                         ok_push = 1;
  99                         break;
 100                 }
 101         } else {
 102                 dev = NULL;
 103         }
 104
 105         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 106         if (!pc) {
 107                 if (dev == NULL)
 108                         return -EINVAL;
 109                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 110                                      &mirred_idx_gen, &mirred_hash_info);
 111                 if (IS_ERR(pc))
 112                         return PTR_ERR(pc);
 113                 ret = ACT_P_CREATED;
 114         } else {
 115                 if (!ovr) {
 116                         tcf_mirred_release(to_mirred(pc), bind);
 117                         return -EEXIST;
 118                 }
 119         }
 120         m = to_mirred(pc);
 121
 122         spin_lock_bh(&m->tcf_lock);
 123         m->tcf_action = parm->action;
 124         m->tcfm_eaction = parm->eaction;
 125         if (dev != NULL) {
 126                 m->tcfm_ifindex = parm->ifindex;
 127                 if (ret != ACT_P_CREATED)
 128                         dev_put(m->tcfm_dev);
 129                 dev_hold(dev);
 130                 m->tcfm_dev = dev;
 131                 m->tcfm_ok_push = ok_push;
 132         }
 133         spin_unlock_bh(&m->tcf_lock);
 134         if (ret == ACT_P_CREATED) {
 135                 list_add(&m->tcfm_list, &mirred_list);
 136                 tcf_hash_insert(pc, &mirred_hash_info);
 137         }
 138
 139         return ret;
 140 }
 141
 142 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 143 {
 144         struct tcf_mirred *m = a->priv;
 145
 146         if (m)
 147                 return tcf_mirred_release(m, bind);
 148         return 0;
 149 }
 150
 151 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 152                       struct tcf_result *res)
 153 {
 154         struct tcf_mirred *m = a->priv;
 155         struct net_device *dev;
 156         struct sk_buff *skb2;
 157         u32 at;
 158         int retval, err = 1;
 159
 160         spin_lock(&m->tcf_lock);
 161         m->tcf_tm.lastuse = jiffies;
 162         bstats_update(&m->tcf_bstats, skb);
 163
 164         dev = m->tcfm_dev;
 165         if (!dev) {
 166                 printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
 167                 goto out;
 168         }
 169
 170         if (!(dev->flags & IFF_UP)) {
 171                 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 172                                        dev->name);
 173                 goto out;
 174         }
 175
 176         at = G_TC_AT(skb->tc_verd);
 177         skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
 178         if (skb2 == NULL)
 179                 goto out;
 180
 181         if (!(at & AT_EGRESS)) {
 182                 if (m->tcfm_ok_push)
 183                         skb_push(skb2, skb2->dev->hard_header_len);
 184         }
 185
 186         /* mirror is always swallowed */
 187         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 188                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 189
 190         skb2->skb_iif = skb->dev->ifindex;
 191         skb2->dev = dev;
 192         err = dev_queue_xmit(skb2);
 193
 194 out:
 195         if (err) {
 196                 m->tcf_qstats.overlimits++;
 197                 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 198                         retval = TC_ACT_SHOT;
 199                 else
 200                         retval = m->tcf_action;
 201         } else
 202                 retval = m->tcf_action;
 203         spin_unlock(&m->tcf_lock);
 204
 205         return retval;
 206 }
 207
 208 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 209 {
 210         unsigned char *b = skb_tail_pointer(skb);
 211         struct tcf_mirred *m = a->priv;
 212         struct tc_mirred opt = {
 213                 .index   = m->tcf_index,
 214                 .action  = m->tcf_action,
 215                 .refcnt  = m->tcf_refcnt - ref,
 216                 .bindcnt = m->tcf_bindcnt - bind,
 217                 .eaction = m->tcfm_eaction,
 218                 .ifindex = m->tcfm_ifindex,
 219         };
 220         struct tcf_t t;
 221
 222         if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 223                 goto nla_put_failure;
 224         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 225         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 226         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 227         if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
 228                 goto nla_put_failure;
 229         return skb->len;
 230
 231 nla_put_failure:
 232         nlmsg_trim(skb, b);
 233         return -1;
 234 }
 235
 236 static int mirred_device_event(struct notifier_block *unused,
 237                                unsigned long event, void *ptr)
 238 {
 239         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 240         struct tcf_mirred *m;
 241
 242         if (event == NETDEV_UNREGISTER)
 243                 list_for_each_entry(m, &mirred_list, tcfm_list) {
 244                         if (m->tcfm_dev == dev) {
 245                                 dev_put(dev);
 246                                 m->tcfm_dev = NULL;
 247                         }
 248                 }
 249
 250         return NOTIFY_DONE;
 251 }
 252
 253 static struct notifier_block mirred_device_notifier = {
 254         .notifier_call = mirred_device_event,
 255 };
 256
 257 static struct tc_action_ops act_mirred_ops = {
 258         .kind           =       "mirred",
 259         .hinfo          =       &mirred_hash_info,
 260         .type           =       TCA_ACT_MIRRED,
 261         .capab          =       TCA_CAP_NONE,
 262         .owner          =       THIS_MODULE,
 263         .act            =       tcf_mirred,
 264         .dump           =       tcf_mirred_dump,
 265         .cleanup        =       tcf_mirred_cleanup,
 266         .init           =       tcf_mirred_init,
 267 };
 268
 269 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 270 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 271 MODULE_LICENSE("GPL");
 272
 273 static int __init mirred_init_module(void)
 274 {
 275         int err = register_netdevice_notifier(&mirred_device_notifier);
 276         if (err)
 277                 return err;
 278
 279         err = tcf_hashinfo_init(&mirred_hash_info, MIRRED_TAB_MASK);
 280         if (err) {
 281                 unregister_netdevice_notifier(&mirred_device_notifier);
 282                 return err;
 283         }
 284         pr_info("Mirror/redirect action on\n");
 285         return tcf_register_action(&act_mirred_ops);
 286 }
 287
 288 static void __exit mirred_cleanup_module(void)
 289 {
 290         tcf_unregister_action(&act_mirred_ops);
 291         tcf_hashinfo_destroy(&mirred_hash_info);
 292         unregister_netdevice_notifier(&mirred_device_notifier);
 293 }
 294
 295 module_init(mirred_init_module);
 296 module_exit(mirred_cleanup_module);