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         list_del(&m->tcfm_list);
  39         if (m->tcfm_dev)
  40                 dev_put(m->tcfm_dev);
  41 }
  42
  43 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  44         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  45 };
  46
  47 static int tcf_mirred_init(struct net *net, struct nlattr *nla,
  48                            struct nlattr *est, struct tc_action *a, int ovr,
  49                            int bind)
  50 {
  51         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  52         struct tc_mirred *parm;
  53         struct tcf_mirred *m;
  54         struct net_device *dev;
  55         int ret, ok_push = 0;
  56
  57         if (nla == NULL)
  58                 return -EINVAL;
  59         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  60         if (ret < 0)
  61                 return ret;
  62         if (tb[TCA_MIRRED_PARMS] == NULL)
  63                 return -EINVAL;
  64         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  65         switch (parm->eaction) {
  66         case TCA_EGRESS_MIRROR:
  67         case TCA_EGRESS_REDIR:
  68                 break;
  69         default:
  70                 return -EINVAL;
  71         }
  72         if (parm->ifindex) {
  73                 dev = __dev_get_by_index(net, parm->ifindex);
  74                 if (dev == NULL)
  75                         return -ENODEV;
  76                 switch (dev->type) {
  77                 case ARPHRD_TUNNEL:
  78                 case ARPHRD_TUNNEL6:
  79                 case ARPHRD_SIT:
  80                 case ARPHRD_IPGRE:
  81                 case ARPHRD_VOID:
  82                 case ARPHRD_NONE:
  83                         ok_push = 0;
  84                         break;
  85                 default:
  86                         ok_push = 1;
  87                         break;
  88                 }
  89         } else {
  90                 dev = NULL;
  91         }
  92
  93         if (!tcf_hash_check(parm->index, a, bind)) {
  94                 if (dev == NULL)
  95                         return -EINVAL;
  96                 ret = tcf_hash_create(parm->index, est, a, sizeof(*m), bind);
  97                 if (ret)
  98                         return ret;
  99                 ret = ACT_P_CREATED;
 100         } else {
 101                 if (bind)
 102                         return 0;
 103                 if (!ovr) {
 104                         tcf_hash_release(a, bind);
 105                         return -EEXIST;
 106                 }
 107         }
 108         m = to_mirred(a);
 109
 110         spin_lock_bh(&m->tcf_lock);
 111         m->tcf_action = parm->action;
 112         m->tcfm_eaction = parm->eaction;
 113         if (dev != NULL) {
 114                 m->tcfm_ifindex = parm->ifindex;
 115                 if (ret != ACT_P_CREATED)
 116                         dev_put(m->tcfm_dev);
 117                 dev_hold(dev);
 118                 m->tcfm_dev = dev;
 119                 m->tcfm_ok_push = ok_push;
 120         }
 121         spin_unlock_bh(&m->tcf_lock);
 122         if (ret == ACT_P_CREATED) {
 123                 list_add(&m->tcfm_list, &mirred_list);
 124                 tcf_hash_insert(a);
 125         }
 126
 127         return ret;
 128 }
 129
 130 static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 131                       struct tcf_result *res)
 132 {
 133         struct tcf_mirred *m = a->priv;
 134         struct net_device *dev;
 135         struct sk_buff *skb2;
 136         u32 at;
 137         int retval, err = 1;
 138
 139         spin_lock(&m->tcf_lock);
 140         m->tcf_tm.lastuse = jiffies;
 141         bstats_update(&m->tcf_bstats, skb);
 142
 143         dev = m->tcfm_dev;
 144         if (!dev) {
 145                 printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
 146                 goto out;
 147         }
 148
 149         if (!(dev->flags & IFF_UP)) {
 150                 net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 151                                        dev->name);
 152                 goto out;
 153         }
 154
 155         at = G_TC_AT(skb->tc_verd);
 156         skb2 = skb_clone(skb, GFP_ATOMIC);
 157         if (skb2 == NULL)
 158                 goto out;
 159
 160         if (!(at & AT_EGRESS)) {
 161                 if (m->tcfm_ok_push)
 162                         skb_push(skb2, skb->mac_len);
 163         }
 164
 165         /* mirror is always swallowed */
 166         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 167                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 168
 169         skb2->skb_iif = skb->dev->ifindex;
 170         skb2->dev = dev;
 171         err = dev_queue_xmit(skb2);
 172
 173 out:
 174         if (err) {
 175                 m->tcf_qstats.overlimits++;
 176                 if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 177                         retval = TC_ACT_SHOT;
 178                 else
 179                         retval = m->tcf_action;
 180         } else
 181                 retval = m->tcf_action;
 182         spin_unlock(&m->tcf_lock);
 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         if (event == NETDEV_UNREGISTER)
 222                 list_for_each_entry(m, &mirred_list, tcfm_list) {
 223                         spin_lock_bh(&m->tcf_lock);
 224                         if (m->tcfm_dev == dev) {
 225                                 dev_put(dev);
 226                                 m->tcfm_dev = NULL;
 227                         }
 228                         spin_unlock_bh(&m->tcf_lock);
 229                 }
 230
 231         return NOTIFY_DONE;
 232 }
 233
 234 static struct notifier_block mirred_device_notifier = {
 235         .notifier_call = mirred_device_event,
 236 };
 237
 238 static struct tc_action_ops act_mirred_ops = {
 239         .kind           =       "mirred",
 240         .type           =       TCA_ACT_MIRRED,
 241         .owner          =       THIS_MODULE,
 242         .act            =       tcf_mirred,
 243         .dump           =       tcf_mirred_dump,
 244         .cleanup        =       tcf_mirred_release,
 245         .init           =       tcf_mirred_init,
 246 };
 247
 248 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 249 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 250 MODULE_LICENSE("GPL");
 251
 252 static int __init mirred_init_module(void)
 253 {
 254         int err = register_netdevice_notifier(&mirred_device_notifier);
 255         if (err)
 256                 return err;
 257
 258         pr_info("Mirror/redirect action on\n");
 259         return tcf_register_action(&act_mirred_ops, MIRRED_TAB_MASK);
 260 }
 261
 262 static void __exit mirred_cleanup_module(void)
 263 {
 264         tcf_unregister_action(&act_mirred_ops);
 265         unregister_netdevice_notifier(&mirred_device_notifier);
 266 }
 267
 268 module_init(mirred_init_module);
 269 module_exit(mirred_cleanup_module);