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![Roman Mashak](/assets/img/avatar_default.png)
Add get_fill_size() routine used to calculate the action size when building a batch of events. Signed-off-by: Roman Mashak <mrv@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
491 lines
12 KiB
C
491 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/act_mirred.c packet mirroring and redirect actions
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*
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* Authors: Jamal Hadi Salim (2002-4)
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*
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* TODO: Add ingress support (and socket redirect support)
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/skbuff.h>
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#include <linux/rtnetlink.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/gfp.h>
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#include <linux/if_arp.h>
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#include <net/net_namespace.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <net/pkt_cls.h>
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#include <linux/tc_act/tc_mirred.h>
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#include <net/tc_act/tc_mirred.h>
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static LIST_HEAD(mirred_list);
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static DEFINE_SPINLOCK(mirred_list_lock);
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#define MIRRED_RECURSION_LIMIT 4
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static DEFINE_PER_CPU(unsigned int, mirred_rec_level);
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static bool tcf_mirred_is_act_redirect(int action)
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{
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return action == TCA_EGRESS_REDIR || action == TCA_INGRESS_REDIR;
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}
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static bool tcf_mirred_act_wants_ingress(int action)
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{
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switch (action) {
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case TCA_EGRESS_REDIR:
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case TCA_EGRESS_MIRROR:
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return false;
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case TCA_INGRESS_REDIR:
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case TCA_INGRESS_MIRROR:
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return true;
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default:
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BUG();
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}
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}
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static bool tcf_mirred_can_reinsert(int action)
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{
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switch (action) {
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case TC_ACT_SHOT:
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case TC_ACT_STOLEN:
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case TC_ACT_QUEUED:
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case TC_ACT_TRAP:
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return true;
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}
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return false;
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}
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static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
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{
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return rcu_dereference_protected(m->tcfm_dev,
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lockdep_is_held(&m->tcf_lock));
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}
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static void tcf_mirred_release(struct tc_action *a)
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{
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struct tcf_mirred *m = to_mirred(a);
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struct net_device *dev;
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spin_lock(&mirred_list_lock);
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list_del(&m->tcfm_list);
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spin_unlock(&mirred_list_lock);
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/* last reference to action, no need to lock */
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dev = rcu_dereference_protected(m->tcfm_dev, 1);
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if (dev)
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dev_put(dev);
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}
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static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
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[TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) },
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};
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static unsigned int mirred_net_id;
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static struct tc_action_ops act_mirred_ops;
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static int tcf_mirred_init(struct net *net, struct nlattr *nla,
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struct nlattr *est, struct tc_action **a,
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int ovr, int bind, bool rtnl_held,
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struct tcf_proto *tp,
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struct netlink_ext_ack *extack)
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{
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struct tc_action_net *tn = net_generic(net, mirred_net_id);
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struct nlattr *tb[TCA_MIRRED_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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bool mac_header_xmit = false;
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struct tc_mirred *parm;
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struct tcf_mirred *m;
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struct net_device *dev;
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bool exists = false;
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int ret, err;
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if (!nla) {
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NL_SET_ERR_MSG_MOD(extack, "Mirred requires attributes to be passed");
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return -EINVAL;
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}
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ret = nla_parse_nested_deprecated(tb, TCA_MIRRED_MAX, nla,
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mirred_policy, extack);
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if (ret < 0)
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return ret;
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if (!tb[TCA_MIRRED_PARMS]) {
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NL_SET_ERR_MSG_MOD(extack, "Missing required mirred parameters");
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return -EINVAL;
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}
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parm = nla_data(tb[TCA_MIRRED_PARMS]);
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err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
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if (err < 0)
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return err;
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exists = err;
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if (exists && bind)
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return 0;
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switch (parm->eaction) {
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case TCA_EGRESS_MIRROR:
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case TCA_EGRESS_REDIR:
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case TCA_INGRESS_REDIR:
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case TCA_INGRESS_MIRROR:
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break;
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default:
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if (exists)
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tcf_idr_release(*a, bind);
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else
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tcf_idr_cleanup(tn, parm->index);
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NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
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return -EINVAL;
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}
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if (!exists) {
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if (!parm->ifindex) {
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tcf_idr_cleanup(tn, parm->index);
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NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
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return -EINVAL;
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}
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ret = tcf_idr_create(tn, parm->index, est, a,
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&act_mirred_ops, bind, true);
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if (ret) {
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tcf_idr_cleanup(tn, parm->index);
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return ret;
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}
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ret = ACT_P_CREATED;
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} else if (!ovr) {
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tcf_idr_release(*a, bind);
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return -EEXIST;
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}
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m = to_mirred(*a);
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if (ret == ACT_P_CREATED)
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INIT_LIST_HEAD(&m->tcfm_list);
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err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
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if (err < 0)
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goto release_idr;
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spin_lock_bh(&m->tcf_lock);
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if (parm->ifindex) {
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dev = dev_get_by_index(net, parm->ifindex);
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if (!dev) {
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spin_unlock_bh(&m->tcf_lock);
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err = -ENODEV;
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goto put_chain;
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}
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mac_header_xmit = dev_is_mac_header_xmit(dev);
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rcu_swap_protected(m->tcfm_dev, dev,
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lockdep_is_held(&m->tcf_lock));
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if (dev)
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dev_put(dev);
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m->tcfm_mac_header_xmit = mac_header_xmit;
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}
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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m->tcfm_eaction = parm->eaction;
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spin_unlock_bh(&m->tcf_lock);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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if (ret == ACT_P_CREATED) {
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spin_lock(&mirred_list_lock);
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list_add(&m->tcfm_list, &mirred_list);
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spin_unlock(&mirred_list_lock);
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tcf_idr_insert(tn, *a);
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}
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return ret;
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put_chain:
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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release_idr:
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tcf_idr_release(*a, bind);
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return err;
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}
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static int tcf_mirred_act(struct sk_buff *skb, const struct tc_action *a,
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struct tcf_result *res)
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{
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struct tcf_mirred *m = to_mirred(a);
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struct sk_buff *skb2 = skb;
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bool m_mac_header_xmit;
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struct net_device *dev;
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unsigned int rec_level;
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int retval, err = 0;
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bool use_reinsert;
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bool want_ingress;
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bool is_redirect;
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int m_eaction;
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int mac_len;
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rec_level = __this_cpu_inc_return(mirred_rec_level);
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if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) {
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net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n",
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netdev_name(skb->dev));
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__this_cpu_dec(mirred_rec_level);
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return TC_ACT_SHOT;
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}
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tcf_lastuse_update(&m->tcf_tm);
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bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
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m_mac_header_xmit = READ_ONCE(m->tcfm_mac_header_xmit);
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m_eaction = READ_ONCE(m->tcfm_eaction);
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retval = READ_ONCE(m->tcf_action);
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dev = rcu_dereference_bh(m->tcfm_dev);
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if (unlikely(!dev)) {
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pr_notice_once("tc mirred: target device is gone\n");
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goto out;
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}
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if (unlikely(!(dev->flags & IFF_UP))) {
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net_notice_ratelimited("tc mirred to Houston: device %s is down\n",
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dev->name);
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goto out;
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}
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/* we could easily avoid the clone only if called by ingress and clsact;
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* since we can't easily detect the clsact caller, skip clone only for
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* ingress - that covers the TC S/W datapath.
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*/
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is_redirect = tcf_mirred_is_act_redirect(m_eaction);
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use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
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tcf_mirred_can_reinsert(retval);
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if (!use_reinsert) {
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skb2 = skb_clone(skb, GFP_ATOMIC);
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if (!skb2)
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goto out;
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}
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/* If action's target direction differs than filter's direction,
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* and devices expect a mac header on xmit, then mac push/pull is
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* needed.
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*/
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want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
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if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
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if (!skb_at_tc_ingress(skb)) {
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/* caught at egress, act ingress: pull mac */
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mac_len = skb_network_header(skb) - skb_mac_header(skb);
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skb_pull_rcsum(skb2, mac_len);
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} else {
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/* caught at ingress, act egress: push mac */
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skb_push_rcsum(skb2, skb->mac_len);
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}
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}
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skb2->skb_iif = skb->dev->ifindex;
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skb2->dev = dev;
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/* mirror is always swallowed */
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if (is_redirect) {
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skb2->tc_redirected = 1;
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skb2->tc_from_ingress = skb2->tc_at_ingress;
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if (skb2->tc_from_ingress)
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skb2->tstamp = 0;
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/* let's the caller reinsert the packet, if possible */
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if (use_reinsert) {
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res->ingress = want_ingress;
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res->qstats = this_cpu_ptr(m->common.cpu_qstats);
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skb_tc_reinsert(skb, res);
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__this_cpu_dec(mirred_rec_level);
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return TC_ACT_CONSUMED;
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}
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}
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if (!want_ingress)
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err = dev_queue_xmit(skb2);
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else
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err = netif_receive_skb(skb2);
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if (err) {
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out:
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qstats_overlimit_inc(this_cpu_ptr(m->common.cpu_qstats));
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if (tcf_mirred_is_act_redirect(m_eaction))
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retval = TC_ACT_SHOT;
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}
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__this_cpu_dec(mirred_rec_level);
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return retval;
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}
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static void tcf_stats_update(struct tc_action *a, u64 bytes, u32 packets,
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u64 lastuse, bool hw)
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{
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struct tcf_mirred *m = to_mirred(a);
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struct tcf_t *tm = &m->tcf_tm;
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_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats), bytes, packets);
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if (hw)
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_bstats_cpu_update(this_cpu_ptr(a->cpu_bstats_hw),
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bytes, packets);
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tm->lastuse = max_t(u64, tm->lastuse, lastuse);
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}
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static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
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int ref)
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{
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unsigned char *b = skb_tail_pointer(skb);
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struct tcf_mirred *m = to_mirred(a);
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struct tc_mirred opt = {
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.index = m->tcf_index,
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.refcnt = refcount_read(&m->tcf_refcnt) - ref,
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.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
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};
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struct net_device *dev;
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struct tcf_t t;
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spin_lock_bh(&m->tcf_lock);
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opt.action = m->tcf_action;
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opt.eaction = m->tcfm_eaction;
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dev = tcf_mirred_dev_dereference(m);
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if (dev)
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opt.ifindex = dev->ifindex;
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if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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tcf_tm_dump(&t, &m->tcf_tm);
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if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
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goto nla_put_failure;
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spin_unlock_bh(&m->tcf_lock);
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return skb->len;
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nla_put_failure:
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spin_unlock_bh(&m->tcf_lock);
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nlmsg_trim(skb, b);
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return -1;
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}
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static int tcf_mirred_walker(struct net *net, struct sk_buff *skb,
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struct netlink_callback *cb, int type,
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const struct tc_action_ops *ops,
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struct netlink_ext_ack *extack)
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{
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struct tc_action_net *tn = net_generic(net, mirred_net_id);
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return tcf_generic_walker(tn, skb, cb, type, ops, extack);
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}
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static int tcf_mirred_search(struct net *net, struct tc_action **a, u32 index)
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{
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struct tc_action_net *tn = net_generic(net, mirred_net_id);
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return tcf_idr_search(tn, a, index);
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}
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static int mirred_device_event(struct notifier_block *unused,
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unsigned long event, void *ptr)
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{
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struct net_device *dev = netdev_notifier_info_to_dev(ptr);
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struct tcf_mirred *m;
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ASSERT_RTNL();
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if (event == NETDEV_UNREGISTER) {
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spin_lock(&mirred_list_lock);
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list_for_each_entry(m, &mirred_list, tcfm_list) {
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spin_lock_bh(&m->tcf_lock);
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if (tcf_mirred_dev_dereference(m) == dev) {
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dev_put(dev);
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/* Note : no rcu grace period necessary, as
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* net_device are already rcu protected.
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*/
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RCU_INIT_POINTER(m->tcfm_dev, NULL);
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}
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spin_unlock_bh(&m->tcf_lock);
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}
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spin_unlock(&mirred_list_lock);
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}
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return NOTIFY_DONE;
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}
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static struct notifier_block mirred_device_notifier = {
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.notifier_call = mirred_device_event,
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};
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static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
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{
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struct tcf_mirred *m = to_mirred(a);
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struct net_device *dev;
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rcu_read_lock();
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dev = rcu_dereference(m->tcfm_dev);
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if (dev)
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dev_hold(dev);
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rcu_read_unlock();
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return dev;
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}
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static void tcf_mirred_put_dev(struct net_device *dev)
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{
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dev_put(dev);
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}
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static size_t tcf_mirred_get_fill_size(const struct tc_action *act)
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{
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return nla_total_size(sizeof(struct tc_mirred));
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}
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static struct tc_action_ops act_mirred_ops = {
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.kind = "mirred",
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.id = TCA_ID_MIRRED,
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.owner = THIS_MODULE,
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.act = tcf_mirred_act,
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.stats_update = tcf_stats_update,
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.dump = tcf_mirred_dump,
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.cleanup = tcf_mirred_release,
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.init = tcf_mirred_init,
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.walk = tcf_mirred_walker,
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.lookup = tcf_mirred_search,
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.get_fill_size = tcf_mirred_get_fill_size,
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.size = sizeof(struct tcf_mirred),
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.get_dev = tcf_mirred_get_dev,
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.put_dev = tcf_mirred_put_dev,
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};
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static __net_init int mirred_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, mirred_net_id);
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return tc_action_net_init(tn, &act_mirred_ops);
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}
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static void __net_exit mirred_exit_net(struct list_head *net_list)
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{
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tc_action_net_exit(net_list, mirred_net_id);
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}
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static struct pernet_operations mirred_net_ops = {
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.init = mirred_init_net,
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.exit_batch = mirred_exit_net,
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.id = &mirred_net_id,
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.size = sizeof(struct tc_action_net),
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};
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MODULE_AUTHOR("Jamal Hadi Salim(2002)");
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MODULE_DESCRIPTION("Device Mirror/redirect actions");
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MODULE_LICENSE("GPL");
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static int __init mirred_init_module(void)
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{
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int err = register_netdevice_notifier(&mirred_device_notifier);
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if (err)
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return err;
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pr_info("Mirror/redirect action on\n");
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return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
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}
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static void __exit mirred_cleanup_module(void)
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{
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tcf_unregister_action(&act_mirred_ops, &mirred_net_ops);
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unregister_netdevice_notifier(&mirred_device_notifier);
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}
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module_init(mirred_init_module);
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module_exit(mirred_cleanup_module);
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