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