linux/net/sched/act_mirred.c
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   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
  33static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
  34static u32 mirred_idx_gen;
  35static DEFINE_RWLOCK(mirred_lock);
  36static LIST_HEAD(mirred_list);
  37
  38static struct tcf_hashinfo mirred_hash_info = {
  39        .htab   =       tcf_mirred_ht,
  40        .hmask  =       MIRRED_TAB_MASK,
  41        .lock   =       &mirred_lock,
  42};
  43
  44static int tcf_mirred_release(struct tcf_mirred *m, int bind)
  45{
  46        if (m) {
  47                if (bind)
  48                        m->tcf_bindcnt--;
  49                m->tcf_refcnt--;
  50                if (!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
  51                        list_del(&m->tcfm_list);
  52                        if (m->tcfm_dev)
  53                                dev_put(m->tcfm_dev);
  54                        tcf_hash_destroy(&m->common, &mirred_hash_info);
  55                        return 1;
  56                }
  57        }
  58        return 0;
  59}
  60
  61static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
  62        [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
  63};
  64
  65static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
  66                           struct tc_action *a, int ovr, int bind)
  67{
  68        struct nlattr *tb[TCA_MIRRED_MAX + 1];
  69        struct tc_mirred *parm;
  70        struct tcf_mirred *m;
  71        struct tcf_common *pc;
  72        struct net_device *dev;
  73        int ret, ok_push = 0;
  74
  75        if (nla == NULL)
  76                return -EINVAL;
  77        ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
  78        if (ret < 0)
  79                return ret;
  80        if (tb[TCA_MIRRED_PARMS] == NULL)
  81                return -EINVAL;
  82        parm = nla_data(tb[TCA_MIRRED_PARMS]);
  83        switch (parm->eaction) {
  84        case TCA_EGRESS_MIRROR:
  85        case TCA_EGRESS_REDIR:
  86                break;
  87        default:
  88                return -EINVAL;
  89        }
  90        if (parm->ifindex) {
  91                dev = __dev_get_by_index(&init_net, parm->ifindex);
  92                if (dev == NULL)
  93                        return -ENODEV;
  94                switch (dev->type) {
  95                case ARPHRD_TUNNEL:
  96                case ARPHRD_TUNNEL6:
  97                case ARPHRD_SIT:
  98                case ARPHRD_IPGRE:
  99                case ARPHRD_VOID:
 100                case ARPHRD_NONE:
 101                        ok_push = 0;
 102                        break;
 103                default:
 104                        ok_push = 1;
 105                        break;
 106                }
 107        } else {
 108                dev = NULL;
 109        }
 110
 111        pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
 112        if (!pc) {
 113                if (dev == NULL)
 114                        return -EINVAL;
 115                pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
 116                                     &mirred_idx_gen, &mirred_hash_info);
 117                if (IS_ERR(pc))
 118                        return PTR_ERR(pc);
 119                ret = ACT_P_CREATED;
 120        } else {
 121                if (!ovr) {
 122                        tcf_mirred_release(to_mirred(pc), bind);
 123                        return -EEXIST;
 124                }
 125        }
 126        m = to_mirred(pc);
 127
 128        spin_lock_bh(&m->tcf_lock);
 129        m->tcf_action = parm->action;
 130        m->tcfm_eaction = parm->eaction;
 131        if (dev != NULL) {
 132                m->tcfm_ifindex = parm->ifindex;
 133                if (ret != ACT_P_CREATED)
 134                        dev_put(m->tcfm_dev);
 135                dev_hold(dev);
 136                m->tcfm_dev = dev;
 137                m->tcfm_ok_push = ok_push;
 138        }
 139        spin_unlock_bh(&m->tcf_lock);
 140        if (ret == ACT_P_CREATED) {
 141                list_add(&m->tcfm_list, &mirred_list);
 142                tcf_hash_insert(pc, &mirred_hash_info);
 143        }
 144
 145        return ret;
 146}
 147
 148static int tcf_mirred_cleanup(struct tc_action *a, int bind)
 149{
 150        struct tcf_mirred *m = a->priv;
 151
 152        if (m)
 153                return tcf_mirred_release(m, bind);
 154        return 0;
 155}
 156
 157static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
 158                      struct tcf_result *res)
 159{
 160        struct tcf_mirred *m = a->priv;
 161        struct net_device *dev;
 162        struct sk_buff *skb2;
 163        u32 at;
 164        int retval, err = 1;
 165
 166        spin_lock(&m->tcf_lock);
 167        m->tcf_tm.lastuse = jiffies;
 168        bstats_update(&m->tcf_bstats, skb);
 169
 170        dev = m->tcfm_dev;
 171        if (!dev) {
 172                printk_once(KERN_NOTICE "tc mirred: target device is gone\n");
 173                goto out;
 174        }
 175
 176        if (!(dev->flags & IFF_UP)) {
 177                net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
 178                                       dev->name);
 179                goto out;
 180        }
 181
 182        at = G_TC_AT(skb->tc_verd);
 183        skb2 = skb_act_clone(skb, GFP_ATOMIC, m->tcf_action);
 184        if (skb2 == NULL)
 185                goto out;
 186
 187        if (!(at & AT_EGRESS)) {
 188                if (m->tcfm_ok_push)
 189                        skb_push(skb2, skb2->dev->hard_header_len);
 190        }
 191
 192        /* mirror is always swallowed */
 193        if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 194                skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);
 195
 196        skb2->skb_iif = skb->dev->ifindex;
 197        skb2->dev = dev;
 198        err = dev_queue_xmit(skb2);
 199
 200out:
 201        if (err) {
 202                m->tcf_qstats.overlimits++;
 203                if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
 204                        retval = TC_ACT_SHOT;
 205                else
 206                        retval = m->tcf_action;
 207        } else
 208                retval = m->tcf_action;
 209        spin_unlock(&m->tcf_lock);
 210
 211        return retval;
 212}
 213
 214static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 215{
 216        unsigned char *b = skb_tail_pointer(skb);
 217        struct tcf_mirred *m = a->priv;
 218        struct tc_mirred opt = {
 219                .index   = m->tcf_index,
 220                .action  = m->tcf_action,
 221                .refcnt  = m->tcf_refcnt - ref,
 222                .bindcnt = m->tcf_bindcnt - bind,
 223                .eaction = m->tcfm_eaction,
 224                .ifindex = m->tcfm_ifindex,
 225        };
 226        struct tcf_t t;
 227
 228        if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 229                goto nla_put_failure;
 230        t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
 231        t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
 232        t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
 233        if (nla_put(skb, TCA_MIRRED_TM, sizeof(t), &t))
 234                goto nla_put_failure;
 235        return skb->len;
 236
 237nla_put_failure:
 238        nlmsg_trim(skb, b);
 239        return -1;
 240}
 241
 242static int mirred_device_event(struct notifier_block *unused,
 243                               unsigned long event, void *ptr)
 244{
 245        struct net_device *dev = ptr;
 246        struct tcf_mirred *m;
 247
 248        if (event == NETDEV_UNREGISTER)
 249                list_for_each_entry(m, &mirred_list, tcfm_list) {
 250                        if (m->tcfm_dev == dev) {
 251                                dev_put(dev);
 252                                m->tcfm_dev = NULL;
 253                        }
 254                }
 255
 256        return NOTIFY_DONE;
 257}
 258
 259static struct notifier_block mirred_device_notifier = {
 260        .notifier_call = mirred_device_event,
 261};
 262
 263
 264static struct tc_action_ops act_mirred_ops = {
 265        .kind           =       "mirred",
 266        .hinfo          =       &mirred_hash_info,
 267        .type           =       TCA_ACT_MIRRED,
 268        .capab          =       TCA_CAP_NONE,
 269        .owner          =       THIS_MODULE,
 270        .act            =       tcf_mirred,
 271        .dump           =       tcf_mirred_dump,
 272        .cleanup        =       tcf_mirred_cleanup,
 273        .lookup         =       tcf_hash_search,
 274        .init           =       tcf_mirred_init,
 275        .walk           =       tcf_generic_walker
 276};
 277
 278MODULE_AUTHOR("Jamal Hadi Salim(2002)");
 279MODULE_DESCRIPTION("Device Mirror/redirect actions");
 280MODULE_LICENSE("GPL");
 281
 282static int __init mirred_init_module(void)
 283{
 284        int err = register_netdevice_notifier(&mirred_device_notifier);
 285        if (err)
 286                return err;
 287
 288        pr_info("Mirror/redirect action on\n");
 289        return tcf_register_action(&act_mirred_ops);
 290}
 291
 292static void __exit mirred_cleanup_module(void)
 293{
 294        unregister_netdevice_notifier(&mirred_device_notifier);
 295        tcf_unregister_action(&act_mirred_ops);
 296}
 297
 298module_init(mirred_init_module);
 299module_exit(mirred_cleanup_module);
 300
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