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root/net/sched/act_mirred.c

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DEFINITIONS

This source file includes following definitions.
  1. tcf_mirred_release
  2. tcf_mirred_init
  3. tcf_mirred_cleanup
  4. tcf_mirred
  5. tcf_mirred_dump
  6. mirred_init_module
  7. mirred_cleanup_module

/*
 * net/sched/mirred.c   packet mirroring and redirect actions
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Authors:     Jamal Hadi Salim (2002-4)
 *
 * TODO: Add ingress support (and socket redirect support)
 *
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <linux/tc_act/tc_mirred.h>
#include <net/tc_act/tc_mirred.h>

#include <linux/if_arp.h>

#define MIRRED_TAB_MASK     7
static struct tcf_common *tcf_mirred_ht[MIRRED_TAB_MASK + 1];
static u32 mirred_idx_gen;
static DEFINE_RWLOCK(mirred_lock);

static struct tcf_hashinfo mirred_hash_info = {
        .htab   =       tcf_mirred_ht,
        .hmask  =       MIRRED_TAB_MASK,
        .lock   =       &mirred_lock,
};

static inline int tcf_mirred_release(struct tcf_mirred *m, int bind)
{
        if (m) {
                if (bind)
                        m->tcf_bindcnt--;
                m->tcf_refcnt--;
                if(!m->tcf_bindcnt && m->tcf_refcnt <= 0) {
                        dev_put(m->tcfm_dev);
                        tcf_hash_destroy(&m->common, &mirred_hash_info);
                        return 1;
                }
        }
        return 0;
}

static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
        [TCA_MIRRED_PARMS]      = { .len = sizeof(struct tc_mirred) },
};

static int tcf_mirred_init(struct nlattr *nla, struct nlattr *est,
                           struct tc_action *a, int ovr, int bind)
{
        struct nlattr *tb[TCA_MIRRED_MAX + 1];
        struct tc_mirred *parm;
        struct tcf_mirred *m;
        struct tcf_common *pc;
        struct net_device *dev = NULL;
        int ret = 0, err;
        int ok_push = 0;

        if (nla == NULL)
                return -EINVAL;

        err = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy);
        if (err < 0)
                return err;

        if (tb[TCA_MIRRED_PARMS] == NULL)
                return -EINVAL;
        parm = nla_data(tb[TCA_MIRRED_PARMS]);

        if (parm->ifindex) {
                dev = __dev_get_by_index(&init_net, parm->ifindex);
                if (dev == NULL)
                        return -ENODEV;
                switch (dev->type) {
                        case ARPHRD_TUNNEL:
                        case ARPHRD_TUNNEL6:
                        case ARPHRD_SIT:
                        case ARPHRD_IPGRE:
                        case ARPHRD_VOID:
                        case ARPHRD_NONE:
                                ok_push = 0;
                                break;
                        default:
                                ok_push = 1;
                                break;
                }
        }

        pc = tcf_hash_check(parm->index, a, bind, &mirred_hash_info);
        if (!pc) {
                if (!parm->ifindex)
                        return -EINVAL;
                pc = tcf_hash_create(parm->index, est, a, sizeof(*m), bind,
                                     &mirred_idx_gen, &mirred_hash_info);
                if (unlikely(!pc))
                        return -ENOMEM;
                ret = ACT_P_CREATED;
        } else {
                if (!ovr) {
                        tcf_mirred_release(to_mirred(pc), bind);
                        return -EEXIST;
                }
        }
        m = to_mirred(pc);

        spin_lock_bh(&m->tcf_lock);
        m->tcf_action = parm->action;
        m->tcfm_eaction = parm->eaction;
        if (parm->ifindex) {
                m->tcfm_ifindex = parm->ifindex;
                if (ret != ACT_P_CREATED)
                        dev_put(m->tcfm_dev);
                m->tcfm_dev = dev;
                dev_hold(dev);
                m->tcfm_ok_push = ok_push;
        }
        spin_unlock_bh(&m->tcf_lock);
        if (ret == ACT_P_CREATED)
                tcf_hash_insert(pc, &mirred_hash_info);

        return ret;
}

static int tcf_mirred_cleanup(struct tc_action *a, int bind)
{
        struct tcf_mirred *m = a->priv;

        if (m)
                return tcf_mirred_release(m, bind);
        return 0;
}

static int tcf_mirred(struct sk_buff *skb, struct tc_action *a,
                      struct tcf_result *res)
{
        struct tcf_mirred *m = a->priv;
        struct net_device *dev;
        struct sk_buff *skb2 = NULL;
        u32 at = G_TC_AT(skb->tc_verd);

        spin_lock(&m->tcf_lock);

        dev = m->tcfm_dev;
        m->tcf_tm.lastuse = jiffies;

        if (!(dev->flags&IFF_UP) ) {
                if (net_ratelimit())
                        printk("mirred to Houston: device %s is gone!\n",
                               dev->name);
bad_mirred:
                if (skb2 != NULL)
                        kfree_skb(skb2);
                m->tcf_qstats.overlimits++;
                m->tcf_bstats.bytes += qdisc_pkt_len(skb);
                m->tcf_bstats.packets++;
                spin_unlock(&m->tcf_lock);
                /* should we be asking for packet to be dropped?
                 * may make sense for redirect case only
                */
                return TC_ACT_SHOT;
        }

        skb2 = skb_act_clone(skb, GFP_ATOMIC);
        if (skb2 == NULL)
                goto bad_mirred;
        if (m->tcfm_eaction != TCA_EGRESS_MIRROR &&
            m->tcfm_eaction != TCA_EGRESS_REDIR) {
                if (net_ratelimit())
                        printk("tcf_mirred unknown action %d\n",
                               m->tcfm_eaction);
                goto bad_mirred;
        }

        m->tcf_bstats.bytes += qdisc_pkt_len(skb2);
        m->tcf_bstats.packets++;
        if (!(at & AT_EGRESS))
                if (m->tcfm_ok_push)
                        skb_push(skb2, skb2->dev->hard_header_len);

        /* mirror is always swallowed */
        if (m->tcfm_eaction != TCA_EGRESS_MIRROR)
                skb2->tc_verd = SET_TC_FROM(skb2->tc_verd, at);

        skb2->dev = dev;
        skb2->iif = skb->dev->ifindex;
        dev_queue_xmit(skb2);
        spin_unlock(&m->tcf_lock);
        return m->tcf_action;
}

static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
{
        unsigned char *b = skb_tail_pointer(skb);
        struct tcf_mirred *m = a->priv;
        struct tc_mirred opt;
        struct tcf_t t;

        opt.index = m->tcf_index;
        opt.action = m->tcf_action;
        opt.refcnt = m->tcf_refcnt - ref;
        opt.bindcnt = m->tcf_bindcnt - bind;
        opt.eaction = m->tcfm_eaction;
        opt.ifindex = m->tcfm_ifindex;
        NLA_PUT(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt);
        t.install = jiffies_to_clock_t(jiffies - m->tcf_tm.install);
        t.lastuse = jiffies_to_clock_t(jiffies - m->tcf_tm.lastuse);
        t.expires = jiffies_to_clock_t(m->tcf_tm.expires);
        NLA_PUT(skb, TCA_MIRRED_TM, sizeof(t), &t);
        return skb->len;

nla_put_failure:
        nlmsg_trim(skb, b);
        return -1;
}

static struct tc_action_ops act_mirred_ops = {
        .kind           =       "mirred",
        .hinfo          =       &mirred_hash_info,
        .type           =       TCA_ACT_MIRRED,
        .capab          =       TCA_CAP_NONE,
        .owner          =       THIS_MODULE,
        .act            =       tcf_mirred,
        .dump           =       tcf_mirred_dump,
        .cleanup        =       tcf_mirred_cleanup,
        .lookup         =       tcf_hash_search,
        .init           =       tcf_mirred_init,
        .walk           =       tcf_generic_walker
};

MODULE_AUTHOR("Jamal Hadi Salim(2002)");
MODULE_DESCRIPTION("Device Mirror/redirect actions");
MODULE_LICENSE("GPL");

static int __init mirred_init_module(void)
{
        printk("Mirror/redirect action on\n");
        return tcf_register_action(&act_mirred_ops);
}

static void __exit mirred_cleanup_module(void)
{
        tcf_unregister_action(&act_mirred_ops);
}

module_init(mirred_init_module);
module_exit(mirred_cleanup_module);

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