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 <asm/uaccess.h>
  16 #include <asm/system.h>
  17 #include <asm/bitops.h>
  18 #include <linux/types.h>
  19 #include <linux/kernel.h>
  20 #include <linux/sched.h>
  21 #include <linux/string.h>
  22 #include <linux/mm.h>
  23 #include <linux/socket.h>
  24 #include <linux/sockios.h>
  25 #include <linux/in.h>
  26 #include <linux/errno.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/rtnetlink.h>
  31 #include <linux/module.h>
  32 #include <linux/init.h>
  33 #include <linux/proc_fs.h>
  34 #include <net/sock.h>
  35 #include <net/pkt_sched.h>
  36 #include <linux/tc_act/tc_mirred.h>
  37 #include <net/tc_act/tc_mirred.h>
  38
  39 #include <linux/etherdevice.h>
  40 #include <linux/if_arp.h>
  41
  42 #define MIRRED_TAB_MASK     7
  43 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  44 static u32 mirred_idx_gen;
  45 static DEFINE_RWLOCK(mirred_lock);
  46
  47 static struct tcf_hashinfo mirred_hash_info = {
  48         .htab   =       tcf_mirred_ht,
  49         .hmask  =       MIRRED_TAB_MASK,
  50         .lock   =       &mirred_lock,
  51 };
  52
  53 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
  54 {
  55         if (m) {
  56                 if (bind)
  57                         m->tcf_bindcnt--;
  58                 m->tcf_refcnt--;
  59                 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  60                         dev_put(m->tcfm_dev);
  61                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  62                         return 1;
  63                 }
  64         }
  65         return 0;
  66 }
  67
  68 static int tcf_mirred_init(struct rtattr *rta, struct rtattr *est,
  69                            struct tc_action *a, int ovr, int bind)
  70 {
  71         struct rtattr *tb[TCA_MIRRED_MAX];
  72         struct tc_mirred *parm;
  73         struct tcf_mirred *m;
  74         struct tcf_common *pc;
  75         struct net_device *dev = NULL;
  76         int ret = 0;
  77         int ok_push = 0;
  78
  79         if (rta == NULL || rtattr_parse_nested(tb, TCA_MIRRED_MAX, rta) < 0)
  80                 return -EINVAL;
  81
  82         if (tb[TCA_MIRRED_PARMS-1] == NULL ||
  83             RTA_PAYLOAD(tb[TCA_MIRRED_PARMS-1]) < sizeof(*parm))
  84                 return -EINVAL;
  85         parm = RTA_DATA(tb[TCA_MIRRED_PARMS-1]);
  86
  87         if (parm->ifindex) {
  88                 dev = __dev_get_by_index(parm->ifindex);
  89                 if (dev == NULL)
  90                         return -ENODEV;
  91                 switch (dev->type) {
  92                         case ARPHRD_TUNNEL:
  93                         case ARPHRD_TUNNEL6:
  94                         case ARPHRD_SIT:
  95                         case ARPHRD_IPGRE:
  96                         case ARPHRD_VOID:
  97                         case ARPHRD_NONE:
  98                                 ok_push = 0;
  99                                 break;
 100                         default:
 101                                 ok_push = 1;
 102                                 break;
 103                 }
 104         }
 105
 106         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 107         if (!pc) {
 108                 if (!parm->ifindex)
 109                         return -EINVAL;
 110                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 111                                      &mirred_idx_gen, &mirred_hash_info);
 112                 if (unlikely(!pc))
 113                         return -ENOMEM;
 114                 ret = ACT_P_CREATED;
 115         } else {
 116                 if (!ovr) {
 117                         tcf_mirred_release(to_mirred(pc), bind);
 118                         return -EEXIST;
 119                 }
 120         }
 121         m = to_mirred(pc);
 122
 123         spin_lock_bh(&m->tcf_lock);
 124         m->tcf_action = parm->action;
 125         m->tcfm_eaction = parm->eaction;
 126         if (parm->ifindex) {
 127                 m->tcfm_ifindex = parm->ifindex;
 128                 if (ret != ACT_P_CREATED)
 129                         dev_put(m->tcfm_dev);
 130                 m->tcfm_dev = dev;
 131                 dev_hold(dev);
 132                 m->tcfm_ok_push = ok_push;
 133         }
 134         spin_unlock_bh(&m->tcf_lock);
 135         if (ret == ACT_P_CREATED)
 136                 tcf_hash_insert(pc, &mirred_hash_info);
 137
 138         return ret;
 139 }
 140
 141 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 142 {
 143         struct tcf_mirred *m = a->priv;
 144
 145         if (m)
 146                 return tcf_mirred_release(m, bind);
 147         return 0;
 148 }
 149
 150 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 151                       struct tcf_result *res)
 152 {
 153         struct tcf_mirred *m = a->priv;
 154         struct net_device *dev;
 155         struct sk_buff *skb2 = NULL;
 156         u32 at = G_TC_AT(skb->tc_verd);
 157
 158         spin_lock(&m->tcf_lock);
 159
 160         dev = m->tcfm_dev;
 161         m->tcf_tm.lastuse = jiffies;
 162
 163         if (!(dev->flags&IFF_UP) ) {
 164                 if (net_ratelimit())
 165                         printk("mirred to Houston: device %s is gone!\n",
 166                                dev->name);
 167 bad_mirred:
 168                 if (skb2 != NULL)
 169                         kfree_skb(skb2);
 170                 m->tcf_qstats.overlimits++;
 171                 m->tcf_bstats.bytes += skb->len;
 172                 m->tcf_bstats.packets++;
 173                 spin_unlock(&m->tcf_lock);
 174                 /* should we be asking for packet to be dropped?
 175                  * may make sense for redirect case only
 176                 */
 177                 return TC_ACT_SHOT;
 178         }
 179
 180         skb2 = skb_clone(skb, GFP_ATOMIC);
 181         if (skb2 == NULL)
 182                 goto bad_mirred;
 183         if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
 184             m->tcfm_eaction != TCA_EGRESS_REDIR) {
 185                 if (net_ratelimit())
 186                         printk("tcf_mirred unknown action %d\n",
 187                                m->tcfm_eaction);
 188                 goto bad_mirred;
 189         }
 190
 191         m->tcf_bstats.bytes += skb2->len;
 192         m->tcf_bstats.packets++;
 193         if (!(at & AT_EGRESS))
 194                 if (m->tcfm_ok_push)
 195                         skb_push(skb2, skb2->dev->hard_header_len);
 196
 197         /* mirror is always swallowed */
 198         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 199                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 200
 201         skb2->dev = dev;
 202         skb2->input_dev = skb->dev;
 203         dev_queue_xmit(skb2);
 204         spin_unlock(&m->tcf_lock);
 205         return m->tcf_action;
 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;
 211         struct tcf_mirred *m = a->priv;
 212         struct tc_mirred opt;
 213         struct tcf_t t;
 214
 215         opt.index = m->tcf_index;
 216         opt.action = m->tcf_action;
 217         opt.refcnt = m->tcf_refcnt - ref;
 218         opt.bindcnt = m->tcf_bindcnt - bind;
 219         opt.eaction = m->tcfm_eaction;
 220         opt.ifindex = m->tcfm_ifindex;
 221         RTA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 222         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 223         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 224         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 225         RTA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 226         return skb->len;
 227
 228 rtattr_failure:
 229         skb_trim(skb, b - skb->data);
 230         return -1;
 231 }
 232
 233 static struct tc_action_ops act_mirred_ops = {
 234         .kind           =       "mirred",
 235         .hinfo          =       &mirred_hash_info,
 236         .type           =       TCA_ACT_MIRRED,
 237         .capab          =       TCA_CAP_NONE,
 238         .owner          =       THIS_MODULE,
 239         .act            =       tcf_mirred,
 240         .dump           =       tcf_mirred_dump,
 241         .cleanup        =       tcf_mirred_cleanup,
 242         .lookup         =       tcf_hash_search,
 243         .init           =       tcf_mirred_init,
 244         .walk           =       tcf_generic_walker
 245 };
 246
 247 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 248 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 249 MODULE_LICENSE("GPL");
 250
 251 static int __init mirred_init_module(void)
 252 {
 253         printk("Mirror/redirect action on\n");
 254         return tcf_register_action(&act_mirred_ops);
 255 }
 256
 257 static void __exit mirred_cleanup_module(void)
 258 {
 259         tcf_unregister_action(&act_mirred_ops);
 260 }
 261
 262 module_init(mirred_init_module);
 263 module_exit(mirred_cleanup_module);