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/netlink.h>
  24 #include <net/pkt_sched.h>
  25 #include <linux/tc_act/tc_mirred.h>
  26 #include <net/tc_act/tc_mirred.h>
  27
  28 #include <linux/if_arp.h>
  29
  30 #define MIRRED_TAB_MASK     7
  31 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  32 static u32 mirred_idx_gen;
  33 static DEFINE_RWLOCK(mirred_lock);
  34
  35 static struct tcf_hashinfo mirred_hash_info = {
  36         .htab   =       tcf_mirred_ht,
  37         .hmask  =       MIRRED_TAB_MASK,
  38         .lock   =       &mirred_lock,
  39 };
  40
  41 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
  42 {
  43         if (m) {
  44                 if (bind)
  45                         m->tcf_bindcnt--;
  46                 m->tcf_refcnt--;
  47                 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  48                         dev_put(m->tcfm_dev);
  49                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  50                         return 1;
  51                 }
  52         }
  53         return 0;
  54 }
  55
  56 static int tcf_mirred_init(struct rtattr *rta, struct rtattr *est,
  57                            struct tc_action *a, int ovr, int bind)
  58 {
  59         struct rtattr *tb[TCA_MIRRED_MAX];
  60         struct tc_mirred *parm;
  61         struct tcf_mirred *m;
  62         struct tcf_common *pc;
  63         struct net_device *dev = NULL;
  64         int ret = 0;
  65         int ok_push = 0;
  66
  67         if (rta == NULL || rtattr_parse_nested(tb, TCA_MIRRED_MAX, rta) < 0)
  68                 return -EINVAL;
  69
  70         if (tb[TCA_MIRRED_PARMS-1] == NULL ||
  71             RTA_PAYLOAD(tb[TCA_MIRRED_PARMS-1]) < sizeof(*parm))
  72                 return -EINVAL;
  73         parm = RTA_DATA(tb[TCA_MIRRED_PARMS-1]);
  74
  75         if (parm->ifindex) {
  76                 dev = __dev_get_by_index(parm->ifindex);
  77                 if (dev == NULL)
  78                         return -ENODEV;
  79                 switch (dev->type) {
  80                         case ARPHRD_TUNNEL:
  81                         case ARPHRD_TUNNEL6:
  82                         case ARPHRD_SIT:
  83                         case ARPHRD_IPGRE:
  84                         case ARPHRD_VOID:
  85                         case ARPHRD_NONE:
  86                                 ok_push = 0;
  87                                 break;
  88                         default:
  89                                 ok_push = 1;
  90                                 break;
  91                 }
  92         }
  93
  94         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
  95         if (!pc) {
  96                 if (!parm->ifindex)
  97                         return -EINVAL;
  98                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
  99                                      &mirred_idx_gen, &mirred_hash_info);
 100                 if (unlikely(!pc))
 101                         return -ENOMEM;
 102                 ret = ACT_P_CREATED;
 103         } else {
 104                 if (!ovr) {
 105                         tcf_mirred_release(to_mirred(pc), bind);
 106                         return -EEXIST;
 107                 }
 108         }
 109         m = to_mirred(pc);
 110
 111         spin_lock_bh(&m->tcf_lock);
 112         m->tcf_action = parm->action;
 113         m->tcfm_eaction = parm->eaction;
 114         if (parm->ifindex) {
 115                 m->tcfm_ifindex = parm->ifindex;
 116                 if (ret != ACT_P_CREATED)
 117                         dev_put(m->tcfm_dev);
 118                 m->tcfm_dev = dev;
 119                 dev_hold(dev);
 120                 m->tcfm_ok_push = ok_push;
 121         }
 122         spin_unlock_bh(&m->tcf_lock);
 123         if (ret == ACT_P_CREATED)
 124                 tcf_hash_insert(pc, &mirred_hash_info);
 125
 126         return ret;
 127 }
 128
 129 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 130 {
 131         struct tcf_mirred *m = a->priv;
 132
 133         if (m)
 134                 return tcf_mirred_release(m, bind);
 135         return 0;
 136 }
 137
 138 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 139                       struct tcf_result *res)
 140 {
 141         struct tcf_mirred *m = a->priv;
 142         struct net_device *dev;
 143         struct sk_buff *skb2 = NULL;
 144         u32 at = G_TC_AT(skb->tc_verd);
 145
 146         spin_lock(&m->tcf_lock);
 147
 148         dev = m->tcfm_dev;
 149         m->tcf_tm.lastuse = jiffies;
 150
 151         if (!(dev->flags&IFF_UP) ) {
 152                 if (net_ratelimit())
 153                         printk("mirred to Houston: device %s is gone!\n",
 154                                dev->name);
 155 bad_mirred:
 156                 if (skb2 != NULL)
 157                         kfree_skb(skb2);
 158                 m->tcf_qstats.overlimits++;
 159                 m->tcf_bstats.bytes += skb->len;
 160                 m->tcf_bstats.packets++;
 161                 spin_unlock(&m->tcf_lock);
 162                 /* should we be asking for packet to be dropped?
 163                  * may make sense for redirect case only
 164                 */
 165                 return TC_ACT_SHOT;
 166         }
 167
 168         skb2 = skb_clone(skb, GFP_ATOMIC);
 169         if (skb2 == NULL)
 170                 goto bad_mirred;
 171         if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
 172             m->tcfm_eaction != TCA_EGRESS_REDIR) {
 173                 if (net_ratelimit())
 174                         printk("tcf_mirred unknown action %d\n",
 175                                m->tcfm_eaction);
 176                 goto bad_mirred;
 177         }
 178
 179         m->tcf_bstats.bytes += skb2->len;
 180         m->tcf_bstats.packets++;
 181         if (!(at & AT_EGRESS))
 182                 if (m->tcfm_ok_push)
 183                         skb_push(skb2, skb2->dev->hard_header_len);
 184
 185         /* mirror is always swallowed */
 186         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 187                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 188
 189         skb2->dev = dev;
 190         skb2->iif = skb->dev->ifindex;
 191         dev_queue_xmit(skb2);
 192         spin_unlock(&m->tcf_lock);
 193         return m->tcf_action;
 194 }
 195
 196 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 197 {
 198         unsigned char *b = skb_tail_pointer(skb);
 199         struct tcf_mirred *m = a->priv;
 200         struct tc_mirred opt;
 201         struct tcf_t t;
 202
 203         opt.index = m->tcf_index;
 204         opt.action = m->tcf_action;
 205         opt.refcnt = m->tcf_refcnt - ref;
 206         opt.bindcnt = m->tcf_bindcnt - bind;
 207         opt.eaction = m->tcfm_eaction;
 208         opt.ifindex = m->tcfm_ifindex;
 209         RTA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 210         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 211         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 212         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 213         RTA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 214         return skb->len;
 215
 216 rtattr_failure:
 217         nlmsg_trim(skb, b);
 218         return -1;
 219 }
 220
 221 static struct tc_action_ops act_mirred_ops = {
 222         .kind           =       "mirred",
 223         .hinfo          =       &mirred_hash_info,
 224         .type           =       TCA_ACT_MIRRED,
 225         .capab          =       TCA_CAP_NONE,
 226         .owner          =       THIS_MODULE,
 227         .act            =       tcf_mirred,
 228         .dump           =       tcf_mirred_dump,
 229         .cleanup        =       tcf_mirred_cleanup,
 230         .lookup         =       tcf_hash_search,
 231         .init           =       tcf_mirred_init,
 232         .walk           =       tcf_generic_walker
 233 };
 234
 235 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 236 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 237 MODULE_LICENSE("GPL");
 238
 239 static int __init mirred_init_module(void)
 240 {
 241         printk("Mirror/redirect action on\n");
 242         return tcf_register_action(&act_mirred_ops);
 243 }
 244
 245 static void __exit mirred_cleanup_module(void)
 246 {
 247         tcf_unregister_action(&act_mirred_ops);
 248 }
 249
 250 module_init(mirred_init_module);
 251 module_exit(mirred_cleanup_module);