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 <linux/gfp.h>
  24 #include <net/net_namespace.h>
  25 #include <net/netlink.h>
  26 #include <net/pkt_sched.h>
  27 #include <linux/tc_act/tc_mirred.h>
  28 #include <net/tc_act/tc_mirred.h>
  29
  30 #include <linux/if_arp.h>
  31
  32 #define MIRRED_TAB_MASK     7
  33 static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  34 static u32 mirred_idx_gen;
  35 static DEFINE_RWLOCK(mirred_lock);
  36
  37 static struct tcf_hashinfo mirred_hash_info = {
  38         .htab   =       tcf_mirred_ht,
  39         .hmask  =       MIRRED_TAB_MASK,
  40         .lock   =       &mirred_lock,
  41 };
  42
  43 static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
  44 {
  45         if (m) {
  46                 if (bind)
  47                         m->tcf_bindcnt--;
  48                 m->tcf_refcnt--;
  49                 if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  50                         dev_put(m->tcfm_dev);
  51                         tcf_hash_destroy(&m->common, &mirred_hash_info);
  52                         return 1;
  53                 }
  54         }
  55         return 0;
  56 }
  57
  58 static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  59         [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  60 };
  61
  62 static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
  63                            struct tc_action *a, int ovr, int bind)
  64 {
  65         struct nlattr *tb[TCA_MIRRED_MAX + 1];
  66         struct tc_mirred *parm;
  67         struct tcf_mirred *m;
  68         struct tcf_common *pc;
  69         struct net_device *dev;
  70         int ret, ok_push = 0;
  71
  72         if (nla == NULL)
  73                 return -EINVAL;
  74         ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  75         if (ret < 0)
  76                 return ret;
  77         if (tb[TCA_MIRRED_PARMS] == NULL)
  78                 return -EINVAL;
  79         parm = nla_data(tb[TCA_MIRRED_PARMS]);
  80         switch (parm->eaction) {
  81         case TCA_EGRESS_MIRROR:
  82         case TCA_EGRESS_REDIR:
  83                 break;
  84         default:
  85                 return -EINVAL;
  86         }
  87         if (parm->ifindex) {
  88                 dev = __dev_get_by_index(&init_net, 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         } else {
 105                 dev = NULL;
 106         }
 107
 108         pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 109         if (!pc) {
 110                 if (dev == NULL)
 111                         return -EINVAL;
 112                 pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 113                                      &mirred_idx_gen, &mirred_hash_info);
 114                 if (IS_ERR(pc))
 115                         return PTR_ERR(pc);
 116                 ret = ACT_P_CREATED;
 117         } else {
 118                 if (!ovr) {
 119                         tcf_mirred_release(to_mirred(pc), bind);
 120                         return -EEXIST;
 121                 }
 122         }
 123         m = to_mirred(pc);
 124
 125         spin_lock_bh(&m->tcf_lock);
 126         m->tcf_action = parm->action;
 127         m->tcfm_eaction = parm->eaction;
 128         if (dev != NULL) {
 129                 m->tcfm_ifindex = parm->ifindex;
 130                 if (ret != ACT_P_CREATED)
 131                         dev_put(m->tcfm_dev);
 132                 dev_hold(dev);
 133                 m->tcfm_dev = dev;
 134                 m->tcfm_ok_push = ok_push;
 135         }
 136         spin_unlock_bh(&m->tcf_lock);
 137         if (ret == ACT_P_CREATED)
 138                 tcf_hash_insert(pc, &mirred_hash_info);
 139
 140         return ret;
 141 }
 142
 143 static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 144 {
 145         struct tcf_mirred *m = a->priv;
 146
 147         if (m)
 148                 return tcf_mirred_release(m, bind);
 149         return 0;
 150 }
 151
 152 static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
 153                       struct tcf_result *res)
 154 {
 155         struct tcf_mirred *m = a->priv;
 156         struct net_device *dev;
 157         struct sk_buff *skb2;
 158         u32 at;
 159         int retval, err = 1;
 160
 161         spin_lock(&m->tcf_lock);
 162         m->tcf_tm.lastuse = jiffies;
 163
 164         dev = m->tcfm_dev;
 165         if (!(dev->flags & IFF_UP)) {
 166                 if (net_ratelimit())
 167                         pr_notice("tc mirred to Houston: device %s is gone!\n",
 168                                   dev->name);
 169                 goto out;
 170         }
 171
 172         skb2 = skb_act_clone(skb, GFP_ATOMIC);
 173         if (skb2 == NULL)
 174                 goto out;
 175
 176         m->tcf_bstats.bytes += qdisc_pkt_len(skb2);
 177         m->tcf_bstats.packets++;
 178         at = G_TC_AT(skb->tc_verd);
 179         if (!(at & AT_EGRESS)) {
 180                 if (m->tcfm_ok_push)
 181                         skb_push(skb2, skb2->dev->hard_header_len);
 182         }
 183
 184         /* mirror is always swallowed */
 185         if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 186                 skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 187
 188         skb2->dev = dev;
 189         skb2->skb_iif = skb->dev->ifindex;
 190         dev_queue_xmit(skb2);
 191         err = 0;
 192
 193 out:
 194         if (err) {
 195                 m->tcf_qstats.overlimits++;
 196                 m->tcf_bstats.bytes += qdisc_pkt_len(skb);
 197                 m->tcf_bstats.packets++;
 198                 /* should we be asking for packet to be dropped?
 199                  * may make sense for redirect case only
 200                  */
 201                 retval = TC_ACT_SHOT;
 202         } else {
 203                 retval = m->tcf_action;
 204         }
 205         spin_unlock(&m->tcf_lock);
 206
 207         return retval;
 208 }
 209
 210 static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 211 {
 212         unsigned char *b = skb_tail_pointer(skb);
 213         struct tcf_mirred *m = a->priv;
 214         struct tc_mirred opt;
 215         struct tcf_t t;
 216
 217         opt.index = m->tcf_index;
 218         opt.action = m->tcf_action;
 219         opt.refcnt = m->tcf_refcnt - ref;
 220         opt.bindcnt = m->tcf_bindcnt - bind;
 221         opt.eaction = m->tcfm_eaction;
 222         opt.ifindex = m->tcfm_ifindex;
 223         NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
 224         t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 225         t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 226         t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 227         NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
 228         return skb->len;
 229
 230 nla_put_failure:
 231         nlmsg_trim(skb, b);
 232         return -1;
 233 }
 234
 235 static struct tc_action_ops act_mirred_ops = {
 236         .kind           =       "mirred",
 237         .hinfo          =       &mirred_hash_info,
 238         .type           =       TCA_ACT_MIRRED,
 239         .capab          =       TCA_CAP_NONE,
 240         .owner          =       THIS_MODULE,
 241         .act            =       tcf_mirred,
 242         .dump           =       tcf_mirred_dump,
 243         .cleanup        =       tcf_mirred_cleanup,
 244         .lookup         =       tcf_hash_search,
 245         .init           =       tcf_mirred_init,
 246         .walk           =       tcf_generic_walker
 247 };
 248
 249 MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 250 MODULE_DESCRIPTION("Device Mirror/redirect actions");
 251 MODULE_LICENSE("GPL");
 252
 253 static int __init mirred_init_module(void)
 254 {
 255         pr_info("Mirror/redirect action on\n");
 256         return tcf_register_action(&act_mirred_ops);
 257 }
 258
 259 static void __exit mirred_cleanup_module(void)
 260 {
 261         tcf_unregister_action(&act_mirred_ops);
 262 }
 263
 264 module_init(mirred_init_module);
 265 module_exit(mirred_cleanup_module);