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/string.h>
  21 #include <linux/mm.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/in.h>
  25 #include <linux/errno.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/skbuff.h>
  29 #include <linux/rtnetlink.h>
  30 #include <linux/module.h>
  31 #include <linux/init.h>
  32 #include <linux/proc_fs.h>
  33 #include <net/sock.h>
  34 #include <net/pkt_sched.h>
  35 #include <linux/tc_act/tc_mirred.h>
  36 #include <net/tc_act/tc_mirred.h>
  37
  38 #include <linux/etherdevice.h>
  39 #include <linux/if_arp.h>
  40
  41 #define MIRRED_TAB_MASK     7
  42 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  43 static u32 mirred_idx_gen;
  44 static DEFINE_RWLOCK(mirred_lock);
  45
  46 static struct tcf_hashinfo mirred_hash_info = {
  47         .htab   =       tcf_mirred_ht,
  48         .hmask  =       MIRRED_TAB_MASK,
  49         .lock   =       &mirred_lock,
  50 };
  51
  52 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
  53 {
  54         if (m) {
  55                 if (bind)
  56                         m->tcf_bindcnt--;
  57                 m->tcf_refcnt--;
  58                 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  59                         dev_put(m->tcfm_dev);
  60                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  61                         return 1;
  62                 }
  63         }
  64         return 0;
  65 }
  66
  67 static int tcf_mirred_init(struct rtattr *rta, struct rtattr *est,
  68                            struct tc_action *a, int ovr, int bind)
  69 {
  70         struct rtattr *tb[TCA_MIRRED_MAX];
  71         struct tc_mirred *parm;
  72         struct tcf_mirred *m;
  73         struct tcf_common *pc;
  74         struct net_device *dev = NULL;
  75         int ret = 0;
  76         int ok_push = 0;
  77
  78         if (rta == NULL || rtattr_parse_nested(tb, TCA_MIRRED_MAX, rta) < 0)
  79                 return -EINVAL;
  80
  81         if (tb[TCA_MIRRED_PARMS-1] == NULL ||
  82             RTA_PAYLOAD(tb[TCA_MIRRED_PARMS-1]) < sizeof(*parm))
  83                 return -EINVAL;
  84         parm = RTA_DATA(tb[TCA_MIRRED_PARMS-1]);
  85
  86         if (parm->ifindex) {
  87                 dev = __dev_get_by_index(parm->ifindex);
  88                 if (dev == NULL)
  89                         return -ENODEV;
  90                 switch (dev->type) {
  91                         case ARPHRD_TUNNEL:
  92                         case ARPHRD_TUNNEL6:
  93                         case ARPHRD_SIT:
  94                         case ARPHRD_IPGRE:
  95                         case ARPHRD_VOID:
  96                         case ARPHRD_NONE:
  97                                 ok_push = 0;
  98                                 break;
  99                         default:
 100                                 ok_push = 1;
 101                                 break;
 102                 }
 103         }
 104
 105         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 106         if (!pc) {
 107                 if (!parm->ifindex)
 108                         return -EINVAL;
 109                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 110                                      &mirred_idx_gen, &mirred_hash_info);
 111                 if (unlikely(!pc))
 112                         return -ENOMEM;
 113                 ret = ACT_P_CREATED;
 114         } else {
 115                 if (!ovr) {
 116                         tcf_mirred_release(to_mirred(pc), bind);
 117                         return -EEXIST;
 118                 }
 119         }
 120         m = to_mirred(pc);
 121
 122         spin_lock_bh(&m->tcf_lock);
 123         m->tcf_action = parm->action;
 124         m->tcfm_eaction = parm->eaction;
 125         if (parm->ifindex) {
 126                 m->tcfm_ifindex = parm->ifindex;
 127                 if (ret != ACT_P_CREATED)
 128                         dev_put(m->tcfm_dev);
 129                 m->tcfm_dev = dev;
 130                 dev_hold(dev);
 131                 m->tcfm_ok_push = ok_push;
 132         }
 133         spin_unlock_bh(&m->tcf_lock);
 134         if (ret == ACT_P_CREATED)
 135                 tcf_hash_insert(pc, &mirred_hash_info);
 136
 137         return ret;
 138 }
 139
 140 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 141 {
 142         struct tcf_mirred *m = a->priv;
 143
 144         if (m)
 145                 return tcf_mirred_release(m, bind);
 146         return 0;
 147 }
 148
 149 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 150                       struct tcf_result *res)
 151 {
 152         struct tcf_mirred *m = a->priv;
 153         struct net_device *dev;
 154         struct sk_buff *skb2 = NULL;
 155         u32 at = G_TC_AT(skb->tc_verd);
 156
 157         spin_lock(&m->tcf_lock);
 158
 159         dev = m->tcfm_dev;
 160         m->tcf_tm.lastuse = jiffies;
 161
 162         if (!(dev->flags&IFF_UP) ) {
 163                 if (net_ratelimit())
 164                         printk("mirred to Houston: device %s is gone!\n",
 165                                dev->name);
 166 bad_mirred:
 167                 if (skb2 != NULL)
 168                         kfree_skb(skb2);
 169                 m->tcf_qstats.overlimits++;
 170                 m->tcf_bstats.bytes += skb->len;
 171                 m->tcf_bstats.packets++;
 172                 spin_unlock(&m->tcf_lock);
 173                 /* should we be asking for packet to be dropped?
 174                  * may make sense for redirect case only
 175                 */
 176                 return TC_ACT_SHOT;
 177         }
 178
 179         skb2 = skb_clone(skb, GFP_ATOMIC);
 180         if (skb2 == NULL)
 181                 goto bad_mirred;
 182         if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
 183             m->tcfm_eaction != TCA_EGRESS_REDIR) {
 184                 if (net_ratelimit())
 185                         printk("tcf_mirred unknown action %d\n",
 186                                m->tcfm_eaction);
 187                 goto bad_mirred;
 188         }
 189
 190         m->tcf_bstats.bytes += skb2->len;
 191         m->tcf_bstats.packets++;
 192         if (!(at & AT_EGRESS))
 193                 if (m->tcfm_ok_push)
 194                         skb_push(skb2, skb2->dev->hard_header_len);
 195
 196         /* mirror is always swallowed */
 197         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 198                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 199
 200         skb2->dev = dev;
 201         skb2->iif = skb->dev->ifindex;
 202         dev_queue_xmit(skb2);
 203         spin_unlock(&m->tcf_lock);
 204         return m->tcf_action;
 205 }
 206
 207 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 208 {
 209         unsigned char *b = skb->tail;
 210         struct tcf_mirred *m = a->priv;
 211         struct tc_mirred opt;
 212         struct tcf_t t;
 213
 214         opt.index = m->tcf_index;
 215         opt.action = m->tcf_action;
 216         opt.refcnt = m->tcf_refcnt - ref;
 217         opt.bindcnt = m->tcf_bindcnt - bind;
 218         opt.eaction = m->tcfm_eaction;
 219         opt.ifindex = m->tcfm_ifindex;
 220         RTA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 221         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 222         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 223         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 224         RTA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 225         return skb->len;
 226
 227 rtattr_failure:
 228         skb_trim(skb, b - skb->data);
 229         return -1;
 230 }
 231
 232 static struct tc_action_ops act_mirred_ops = {
 233         .kind           =       "mirred",
 234         .hinfo          =       &mirred_hash_info,
 235         .type           =       TCA_ACT_MIRRED,
 236         .capab          =       TCA_CAP_NONE,
 237         .owner          =       THIS_MODULE,
 238         .act            =       tcf_mirred,
 239         .dump           =       tcf_mirred_dump,
 240         .cleanup        =       tcf_mirred_cleanup,
 241         .lookup         =       tcf_hash_search,
 242         .init           =       tcf_mirred_init,
 243         .walk           =       tcf_generic_walker
 244 };
 245
 246 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 247 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 248 MODULE_LICENSE("GPL");
 249
 250 static int __init mirred_init_module(void)
 251 {
 252         printk("Mirror/redirect action on\n");
 253         return tcf_register_action(&act_mirred_ops);
 254 }
 255
 256 static void __exit mirred_cleanup_module(void)
 257 {
 258         tcf_unregister_action(&act_mirred_ops);
 259 }
 260
 261 module_init(mirred_init_module);
 262 module_exit(mirred_cleanup_module);