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 <net/net_namespace.h>
  24 #include <net/netlink.h>
  25 #include <net/pkt_sched.h>
  26 #include <linux/tc_act/tc_mirred.h>
  27 #include <net/tc_act/tc_mirred.h>
  28
  29 #include <linux/if_arp.h>
  30
  31 #define MIRRED_TAB_MASK     7
  32 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  33 static u32 mirred_idx_gen;
  34 static DEFINE_RWLOCK(mirred_lock);
  35
  36 static struct tcf_hashinfo mirred_hash_info = {
  37         .htab   =       tcf_mirred_ht,
  38         .hmask  =       MIRRED_TAB_MASK,
  39         .lock   =       &mirred_lock,
  40 };
  41
  42 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
  43 {
  44         if (m) {
  45                 if (bind)
  46                         m->tcf_bindcnt--;
  47                 m->tcf_refcnt--;
  48                 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  49                         dev_put(m->tcfm_dev);
  50                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  51                         return 1;
  52                 }
  53         }
  54         return 0;
  55 }
  56
  57 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  58         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  59 };
  60
  61 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
  62                            struct tc_action *a, int ovr, int bind)
  63 {
  64         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  65         struct tc_mirred *parm;
  66         struct tcf_mirred *m;
  67         struct tcf_common *pc;
  68         struct net_device *dev = NULL;
  69         int ret = 0, err;
  70         int ok_push = 0;
  71
  72         if (nla == NULL)
  73                 return -EINVAL;
  74
  75         err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  76         if (err < 0)
  77                 return err;
  78
  79         if (tb[TCA_MIRRED_PARMS] == NULL)
  80                 return -EINVAL;
  81         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  82
  83         if (parm->ifindex) {
  84                 dev = __dev_get_by_index(&init_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         }
 101
 102         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 103         if (!pc) {
 104                 if (!parm->ifindex)
 105                         return -EINVAL;
 106                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 107                                      &mirred_idx_gen, &mirred_hash_info);
 108                 if (unlikely(!pc))
 109                         return -ENOMEM;
 110                 ret = ACT_P_CREATED;
 111         } else {
 112                 if (!ovr) {
 113                         tcf_mirred_release(to_mirred(pc), bind);
 114                         return -EEXIST;
 115                 }
 116         }
 117         m = to_mirred(pc);
 118
 119         spin_lock_bh(&m->tcf_lock);
 120         m->tcf_action = parm->action;
 121         m->tcfm_eaction = parm->eaction;
 122         if (parm->ifindex) {
 123                 m->tcfm_ifindex = parm->ifindex;
 124                 if (ret != ACT_P_CREATED)
 125                         dev_put(m->tcfm_dev);
 126                 m->tcfm_dev = dev;
 127                 dev_hold(dev);
 128                 m->tcfm_ok_push = ok_push;
 129         }
 130         spin_unlock_bh(&m->tcf_lock);
 131         if (ret == ACT_P_CREATED)
 132                 tcf_hash_insert(pc, &mirred_hash_info);
 133
 134         return ret;
 135 }
 136
 137 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 138 {
 139         struct tcf_mirred *m = a->priv;
 140
 141         if (m)
 142                 return tcf_mirred_release(m, bind);
 143         return 0;
 144 }
 145
 146 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 147                       struct tcf_result *res)
 148 {
 149         struct tcf_mirred *m = a->priv;
 150         struct net_device *dev;
 151         struct sk_buff *skb2 = NULL;
 152         u32 at = G_TC_AT(skb->tc_verd);
 153
 154         spin_lock(&m->tcf_lock);
 155
 156         dev = m->tcfm_dev;
 157         m->tcf_tm.lastuse = jiffies;
 158
 159         if (!(dev->flags&IFF_UP) ) {
 160                 if (net_ratelimit())
 161                         printk("mirred to Houston: device %s is gone!\n",
 162                                dev->name);
 163 bad_mirred:
 164                 if (skb2 != NULL)
 165                         kfree_skb(skb2);
 166                 m->tcf_qstats.overlimits++;
 167                 m->tcf_bstats.bytes += qdisc_pkt_len(skb);
 168                 m->tcf_bstats.packets++;
 169                 spin_unlock(&m->tcf_lock);
 170                 /* should we be asking for packet to be dropped?
 171                  * may make sense for redirect case only
 172                 */
 173                 return TC_ACT_SHOT;
 174         }
 175
 176         skb2 = skb_act_clone(skb, GFP_ATOMIC);
 177         if (skb2 == NULL)
 178                 goto bad_mirred;
 179         if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
 180             m->tcfm_eaction != TCA_EGRESS_REDIR) {
 181                 if (net_ratelimit())
 182                         printk("tcf_mirred unknown action %d\n",
 183                                m->tcfm_eaction);
 184                 goto bad_mirred;
 185         }
 186
 187         m->tcf_bstats.bytes += qdisc_pkt_len(skb2);
 188         m->tcf_bstats.packets++;
 189         if (!(at & AT_EGRESS))
 190                 if (m->tcfm_ok_push)
 191                         skb_push(skb2, skb2->dev->hard_header_len);
 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->dev = dev;
 198         skb2->iif = skb->dev->ifindex;
 199         dev_queue_xmit(skb2);
 200         spin_unlock(&m->tcf_lock);
 201         return m->tcf_action;
 202 }
 203
 204 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 205 {
 206         unsigned char *b = skb_tail_pointer(skb);
 207         struct tcf_mirred *m = a->priv;
 208         struct tc_mirred opt;
 209         struct tcf_t t;
 210
 211         opt.index = m->tcf_index;
 212         opt.action = m->tcf_action;
 213         opt.refcnt = m->tcf_refcnt - ref;
 214         opt.bindcnt = m->tcf_bindcnt - bind;
 215         opt.eaction = m->tcfm_eaction;
 216         opt.ifindex = m->tcfm_ifindex;
 217         NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 218         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 219         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 220         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 221         NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 222         return skb->len;
 223
 224 nla_put_failure:
 225         nlmsg_trim(skb, b);
 226         return -1;
 227 }
 228
 229 static struct tc_action_ops act_mirred_ops = {
 230         .kind           =       "mirred",
 231         .hinfo          =       &mirred_hash_info,
 232         .type           =       TCA_ACT_MIRRED,
 233         .capab          =       TCA_CAP_NONE,
 234         .owner          =       THIS_MODULE,
 235         .act            =       tcf_mirred,
 236         .dump           =       tcf_mirred_dump,
 237         .cleanup        =       tcf_mirred_cleanup,
 238         .lookup         =       tcf_hash_search,
 239         .init           =       tcf_mirred_init,
 240         .walk           =       tcf_generic_walker
 241 };
 242
 243 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 244 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 245 MODULE_LICENSE("GPL");
 246
 247 static int __init mirred_init_module(void)
 248 {
 249         printk("Mirror/redirect action on\n");
 250         return tcf_register_action(&act_mirred_ops);
 251 }
 252
 253 static void __exit mirred_cleanup_module(void)
 254 {
 255         tcf_unregister_action(&act_mirred_ops);
 256 }
 257
 258 module_init(mirred_init_module);
 259 module_exit(mirred_cleanup_module);