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 struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  34 static u32 mirred_idx_gen;
  35 static DEFINE_RWLOCK(mirred_lock);
  36 static LIST_HEAD(mirred_list);
  37
  38 static struct tcf_hashinfo mirred_hash_info = {
  39         .htab   =       tcf_mirred_ht,
  40         .hmask  =       MIRRED_TAB_MASK,
  41         .lock   =       &mirred_lock,
  42 };
  43
  44 static int tcf_mirred_release(struct tcf_mirred *m, int bind)
  45 {
  46         if (m) {
  47                 if (bind)
  48                         m->tcf_bindcnt--;
  49                 m->tcf_refcnt--;
  50                 if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  51                         list_del(&m->tcfm_list);
  52                         if (m->tcfm_dev)
  53                                 dev_put(m->tcfm_dev);
  54                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  55                         return 1;
  56                 }
  57         }
  58         return 0;
  59 }
  60
  61 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  62         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  63 };
  64
  65 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
  66                            struct tc_action *a, int ovr, int bind)
  67 {
  68         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  69         struct tc_mirred *parm;
  70         struct tcf_mirred *m;
  71         struct tcf_common *pc;
  72         struct net_device *dev;
  73         int ret, ok_push = 0;
  74
  75         if (nla == NULL)
  76                 return -EINVAL;
  77         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  78         if (ret < 0)
  79                 return ret;
  80         if (tb[TCA_MIRRED_PARMS] == NULL)
  81                 return -EINVAL;
  82         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  83         switch (parm->eaction) {
  84         case TCA_EGRESS_MIRROR:
  85         case TCA_EGRESS_REDIR:
  86                 break;
  87         default:
  88                 return -EINVAL;
  89         }
  90         if (parm->ifindex) {
  91                 dev = __dev_get_by_index(&init_net, parm->ifindex);
  92                 if (dev == NULL)
  93                         return -ENODEV;
  94                 switch (dev->type) {
  95                 case ARPHRD_TUNNEL:
  96                 case ARPHRD_TUNNEL6:
  97                 case ARPHRD_SIT:
  98                 case ARPHRD_IPGRE:
  99                 case ARPHRD_VOID:
 100                 case ARPHRD_NONE:
 101                         ok_push = 0;
 102                         break;
 103                 default:
 104                         ok_push = 1;
 105                         break;
 106                 }
 107         } else {
 108                 dev = NULL;
 109         }
 110
 111         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 112         if (!pc) {
 113                 if (dev == NULL)
 114                         return -EINVAL;
 115                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 116                                      &mirred_idx_gen, &mirred_hash_info);
 117                 if (IS_ERR(pc))
 118                         return PTR_ERR(pc);
 119                 ret = ACT_P_CREATED;
 120         } else {
 121                 if (!ovr) {
 122                         tcf_mirred_release(to_mirred(pc), bind);
 123                         return -EEXIST;
 124                 }
 125         }
 126         m = to_mirred(pc);
 127
 128         spin_lock_bh(&m->tcf_lock);
 129         m->tcf_action = parm->action;
 130         m->tcfm_eaction = parm->eaction;
 131         if (dev != NULL) {
 132                 m->tcfm_ifindex = parm->ifindex;
 133                 if (ret != ACT_P_CREATED)
 134                         dev_put(m->tcfm_dev);
 135                 dev_hold(dev);
 136                 m->tcfm_dev = dev;
 137                 m->tcfm_ok_push = ok_push;
 138         }
 139         spin_unlock_bh(&m->tcf_lock);
 140         if (ret == ACT_P_CREATED) {
 141                 list_add(&m->tcfm_list, &mirred_list);
 142                 tcf_hash_insert(pc, &mirred_hash_info);
 143         }
 144
 145         return ret;
 146 }
 147
 148 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 149 {
 150         struct tcf_mirred *m = a->priv;
 151
 152         if (m)
 153                 return tcf_mirred_release(m, bind);
 154         return 0;
 155 }
 156
 157 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 158                       struct tcf_result *res)
 159 {
 160         struct tcf_mirred *m = a->priv;
 161         struct net_device *dev;
 162         struct sk_buff *skb2;
 163         u32 at;
 164         int retval, err = 1;
 165
 166         spin_lock(&m->tcf_lock);
 167         m->tcf_tm.lastuse = jiffies;
 168         bstats_update(&m->tcf_bstats, skb);
 169
 170         dev = m->tcfm_dev;
 171         if (!dev) {
 172                 printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
 173                 goto out;
 174         }
 175
 176         if (!(dev->flags & IFF_UP)) {
 177                 if (net_ratelimit())
 178                         pr_notice("tc mirred to Houston: device %s is down\n",
 179                                   dev->name);
 180                 goto out;
 181         }
 182
 183         at = G_TC_AT(skb->tc_verd);
 184         skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
 185         if (skb2 == NULL)
 186                 goto out;
 187
 188         if (!(at & AT_EGRESS)) {
 189                 if (m->tcfm_ok_push)
 190                         skb_push(skb2, skb2->dev->hard_header_len);
 191         }
 192
 193         /* mirror is always swallowed */
 194         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 195                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 196
 197         skb2->skb_iif = skb->dev->ifindex;
 198         skb2->dev = dev;
 199         err = dev_queue_xmit(skb2);
 200
 201 out:
 202         if (err) {
 203                 m->tcf_qstats.overlimits++;
 204                 /* should we be asking for packet to be dropped?
 205                  * may make sense for redirect case only
 206                  */
 207                 retval = TC_ACT_SHOT;
 208         } else {
 209                 retval = m->tcf_action;
 210         }
 211         spin_unlock(&m->tcf_lock);
 212
 213         return retval;
 214 }
 215
 216 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 217 {
 218         unsigned char *b = skb_tail_pointer(skb);
 219         struct tcf_mirred *m = a->priv;
 220         struct tc_mirred opt = {
 221                 .index   = m->tcf_index,
 222                 .action  = m->tcf_action,
 223                 .refcnt  = m->tcf_refcnt - ref,
 224                 .bindcnt = m->tcf_bindcnt - bind,
 225                 .eaction = m->tcfm_eaction,
 226                 .ifindex = m->tcfm_ifindex,
 227         };
 228         struct tcf_t t;
 229
 230         NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 231         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 232         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 233         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 234         NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 235         return skb->len;
 236
 237 nla_put_failure:
 238         nlmsg_trim(skb, b);
 239         return -1;
 240 }
 241
 242 static int mirred_device_event(struct notifier_block *unused,
 243                                unsigned long event, void *ptr)
 244 {
 245         struct net_device *dev = ptr;
 246         struct tcf_mirred *m;
 247
 248         if (event == NETDEV_UNREGISTER)
 249                 list_for_each_entry(m, &mirred_list, tcfm_list) {
 250                         if (m->tcfm_dev == dev) {
 251                                 dev_put(dev);
 252                                 m->tcfm_dev = NULL;
 253                         }
 254                 }
 255
 256         return NOTIFY_DONE;
 257 }
 258
 259 static struct notifier_block mirred_device_notifier = {
 260         .notifier_call = mirred_device_event,
 261 };
 262
 263
 264 static struct tc_action_ops act_mirred_ops = {
 265         .kind           =       "mirred",
 266         .hinfo          =       &mirred_hash_info,
 267         .type           =       TCA_ACT_MIRRED,
 268         .capab          =       TCA_CAP_NONE,
 269         .owner          =       THIS_MODULE,
 270         .act            =       tcf_mirred,
 271         .dump           =       tcf_mirred_dump,
 272         .cleanup        =       tcf_mirred_cleanup,
 273         .lookup         =       tcf_hash_search,
 274         .init           =       tcf_mirred_init,
 275         .walk           =       tcf_generic_walker
 276 };
 277
 278 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 279 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 280 MODULE_LICENSE("GPL");
 281
 282 static int __init mirred_init_module(void)
 283 {
 284         int err = register_netdevice_notifier(&mirred_device_notifier);
 285         if (err)
 286                 return err;
 287
 288         pr_info("Mirror/redirect action on\n");
 289         return tcf_register_action(&act_mirred_ops);
 290 }
 291
 292 static void __exit mirred_cleanup_module(void)
 293 {
 294         unregister_netdevice_notifier(&mirred_device_notifier);
 295         tcf_unregister_action(&act_mirred_ops);
 296 }
 297
 298 module_init(mirred_init_module);
 299 module_exit(mirred_cleanup_module);