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;
  69         int ret, ok_push = 0;
  70
  71         if (nla == NULL)
  72                 return -EINVAL;
  73         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  74         if (ret < 0)
  75                 return ret;
  76         if (tb[TCA_MIRRED_PARMS] == NULL)
  77                 return -EINVAL;
  78         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  79         switch (parm->eaction) {
  80         case TCA_EGRESS_MIRROR:
  81         case TCA_EGRESS_REDIR:
  82                 break;
  83         default:
  84                 return -EINVAL;
  85         }
  86         if (parm->ifindex) {
  87                 dev = __dev_get_by_index(&init_net, 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         } else {
 104                 dev = NULL;
 105         }
 106
 107         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 108         if (!pc) {
 109                 if (dev == NULL)
 110                         return -EINVAL;
 111                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 112                                      &mirred_idx_gen, &mirred_hash_info);
 113                 if (IS_ERR(pc))
 114                         return PTR_ERR(pc);
 115                 ret = ACT_P_CREATED;
 116         } else {
 117                 if (!ovr) {
 118                         tcf_mirred_release(to_mirred(pc), bind);
 119                         return -EEXIST;
 120                 }
 121         }
 122         m = to_mirred(pc);
 123
 124         spin_lock_bh(&m->tcf_lock);
 125         m->tcf_action = parm->action;
 126         m->tcfm_eaction = parm->eaction;
 127         if (dev != NULL) {
 128                 m->tcfm_ifindex = parm->ifindex;
 129                 if (ret != ACT_P_CREATED)
 130                         dev_put(m->tcfm_dev);
 131                 dev_hold(dev);
 132                 m->tcfm_dev = dev;
 133                 m->tcfm_ok_push = ok_push;
 134         }
 135         spin_unlock_bh(&m->tcf_lock);
 136         if (ret == ACT_P_CREATED)
 137                 tcf_hash_insert(pc, &mirred_hash_info);
 138
 139         return ret;
 140 }
 141
 142 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 143 {
 144         struct tcf_mirred *m = a->priv;
 145
 146         if (m)
 147                 return tcf_mirred_release(m, bind);
 148         return 0;
 149 }
 150
 151 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 152                       struct tcf_result *res)
 153 {
 154         struct tcf_mirred *m = a->priv;
 155         struct net_device *dev;
 156         struct sk_buff *skb2;
 157         u32 at;
 158         int retval, err = 1;
 159
 160         spin_lock(&m->tcf_lock);
 161         m->tcf_tm.lastuse = jiffies;
 162
 163         dev = m->tcfm_dev;
 164         if (!(dev->flags & IFF_UP)) {
 165                 if (net_ratelimit())
 166                         printk("mirred to Houston: device %s is gone!\n",
 167                                dev->name);
 168                 goto out;
 169         }
 170
 171         skb2 = skb_act_clone(skb, GFP_ATOMIC);
 172         if (skb2 == NULL)
 173                 goto out;
 174
 175         m->tcf_bstats.bytes += qdisc_pkt_len(skb2);
 176         m->tcf_bstats.packets++;
 177         at = G_TC_AT(skb->tc_verd);
 178         if (!(at & AT_EGRESS)) {
 179                 if (m->tcfm_ok_push)
 180                         skb_push(skb2, skb2->dev->hard_header_len);
 181         }
 182
 183         /* mirror is always swallowed */
 184         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 185                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 186
 187         skb2->dev = dev;
 188         skb2->skb_iif = skb->dev->ifindex;
 189         dev_queue_xmit(skb2);
 190         err = 0;
 191
 192 out:
 193         if (err) {
 194                 m->tcf_qstats.overlimits++;
 195                 m->tcf_bstats.bytes += qdisc_pkt_len(skb);
 196                 m->tcf_bstats.packets++;
 197                 /* should we be asking for packet to be dropped?
 198                  * may make sense for redirect case only
 199                  */
 200                 retval = TC_ACT_SHOT;
 201         } else {
 202                 retval = m->tcf_action;
 203         }
 204         spin_unlock(&m->tcf_lock);
 205
 206         return retval;
 207 }
 208
 209 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 210 {
 211         unsigned char *b = skb_tail_pointer(skb);
 212         struct tcf_mirred *m = a->priv;
 213         struct tc_mirred opt;
 214         struct tcf_t t;
 215
 216         opt.index = m->tcf_index;
 217         opt.action = m->tcf_action;
 218         opt.refcnt = m->tcf_refcnt - ref;
 219         opt.bindcnt = m->tcf_bindcnt - bind;
 220         opt.eaction = m->tcfm_eaction;
 221         opt.ifindex = m->tcfm_ifindex;
 222         NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 223         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 224         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 225         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 226         NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 227         return skb->len;
 228
 229 nla_put_failure:
 230         nlmsg_trim(skb, b);
 231         return -1;
 232 }
 233
 234 static struct tc_action_ops act_mirred_ops = {
 235         .kind           =       "mirred",
 236         .hinfo          =       &mirred_hash_info,
 237         .type           =       TCA_ACT_MIRRED,
 238         .capab          =       TCA_CAP_NONE,
 239         .owner          =       THIS_MODULE,
 240         .act            =       tcf_mirred,
 241         .dump           =       tcf_mirred_dump,
 242         .cleanup        =       tcf_mirred_cleanup,
 243         .lookup         =       tcf_hash_search,
 244         .init           =       tcf_mirred_init,
 245         .walk           =       tcf_generic_walker
 246 };
 247
 248 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 249 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 250 MODULE_LICENSE("GPL");
 251
 252 static int __init mirred_init_module(void)
 253 {
 254         printk("Mirror/redirect action on\n");
 255         return tcf_register_action(&act_mirred_ops);
 256 }
 257
 258 static void __exit mirred_cleanup_module(void)
 259 {
 260         tcf_unregister_action(&act_mirred_ops);
 261 }
 262
 263 module_init(mirred_init_module);
 264 module_exit(mirred_cleanup_module);