![Cong Wang](/assets/img/avatar_default.png)
All TC actions call tcf_idr_insert() for new action at the end of their ->init(), so we can actually move it to a central place in tcf_action_init_1(). And once the action is inserted into the global IDR, other parallel process could free it immediately as its refcnt is still 1, so we can not fail after this, we need to move it after the goto action validation to avoid handling the failure case after insertion. This is found during code review, is not directly triggered by syzbot. And this prepares for the next patch. Cc: Vlad Buslov <vladbu@mellanox.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
310 lines
7.4 KiB
C
310 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/act_gact.c Generic actions
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*
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* copyright Jamal Hadi Salim (2002-4)
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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 <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_gact.h>
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#include <net/tc_act/tc_gact.h>
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static unsigned int gact_net_id;
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static struct tc_action_ops act_gact_ops;
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#ifdef CONFIG_GACT_PROB
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static int gact_net_rand(struct tcf_gact *gact)
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{
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smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
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if (prandom_u32() % gact->tcfg_pval)
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return gact->tcf_action;
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return gact->tcfg_paction;
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}
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static int gact_determ(struct tcf_gact *gact)
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{
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u32 pack = atomic_inc_return(&gact->packets);
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smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
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if (pack % gact->tcfg_pval)
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return gact->tcf_action;
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return gact->tcfg_paction;
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}
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typedef int (*g_rand)(struct tcf_gact *gact);
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static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
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#endif /* CONFIG_GACT_PROB */
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static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
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[TCA_GACT_PARMS] = { .len = sizeof(struct tc_gact) },
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[TCA_GACT_PROB] = { .len = sizeof(struct tc_gact_p) },
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};
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static int tcf_gact_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, u32 flags,
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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, gact_net_id);
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struct nlattr *tb[TCA_GACT_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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struct tc_gact *parm;
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struct tcf_gact *gact;
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int ret = 0;
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u32 index;
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int err;
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#ifdef CONFIG_GACT_PROB
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struct tc_gact_p *p_parm = NULL;
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#endif
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if (nla == NULL)
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return -EINVAL;
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err = nla_parse_nested_deprecated(tb, TCA_GACT_MAX, nla, gact_policy,
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NULL);
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if (err < 0)
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return err;
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if (tb[TCA_GACT_PARMS] == NULL)
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return -EINVAL;
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parm = nla_data(tb[TCA_GACT_PARMS]);
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index = parm->index;
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#ifndef CONFIG_GACT_PROB
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if (tb[TCA_GACT_PROB] != NULL)
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return -EOPNOTSUPP;
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#else
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if (tb[TCA_GACT_PROB]) {
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p_parm = nla_data(tb[TCA_GACT_PROB]);
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if (p_parm->ptype >= MAX_RAND)
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return -EINVAL;
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if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
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NL_SET_ERR_MSG(extack,
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"goto chain not allowed on fallback");
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return -EINVAL;
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}
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}
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#endif
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err = tcf_idr_check_alloc(tn, &index, a, bind);
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if (!err) {
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ret = tcf_idr_create_from_flags(tn, index, est, a,
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&act_gact_ops, bind, flags);
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if (ret) {
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tcf_idr_cleanup(tn, 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 (err > 0) {
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if (bind)/* dont override defaults */
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return 0;
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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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} else {
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return err;
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}
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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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gact = to_gact(*a);
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spin_lock_bh(&gact->tcf_lock);
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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#ifdef CONFIG_GACT_PROB
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if (p_parm) {
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gact->tcfg_paction = p_parm->paction;
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gact->tcfg_pval = max_t(u16, 1, p_parm->pval);
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/* Make sure tcfg_pval is written before tcfg_ptype
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* coupled with smp_rmb() in gact_net_rand() & gact_determ()
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*/
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smp_wmb();
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gact->tcfg_ptype = p_parm->ptype;
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}
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#endif
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spin_unlock_bh(&gact->tcf_lock);
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if (goto_ch)
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tcf_chain_put_by_act(goto_ch);
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return ret;
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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_gact_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_gact *gact = to_gact(a);
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int action = READ_ONCE(gact->tcf_action);
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#ifdef CONFIG_GACT_PROB
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{
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u32 ptype = READ_ONCE(gact->tcfg_ptype);
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if (ptype)
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action = gact_rand[ptype](gact);
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}
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#endif
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tcf_action_update_bstats(&gact->common, skb);
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if (action == TC_ACT_SHOT)
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tcf_action_inc_drop_qstats(&gact->common);
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tcf_lastuse_update(&gact->tcf_tm);
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return action;
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}
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static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u64 packets,
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u64 drops, u64 lastuse, bool hw)
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{
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struct tcf_gact *gact = to_gact(a);
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int action = READ_ONCE(gact->tcf_action);
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struct tcf_t *tm = &gact->tcf_tm;
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tcf_action_update_stats(a, bytes, packets,
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action == TC_ACT_SHOT ? packets : drops, hw);
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tm->lastuse = max_t(u64, tm->lastuse, lastuse);
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}
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static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
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int bind, int ref)
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{
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unsigned char *b = skb_tail_pointer(skb);
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struct tcf_gact *gact = to_gact(a);
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struct tc_gact opt = {
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.index = gact->tcf_index,
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.refcnt = refcount_read(&gact->tcf_refcnt) - ref,
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.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
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};
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struct tcf_t t;
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spin_lock_bh(&gact->tcf_lock);
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opt.action = gact->tcf_action;
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if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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#ifdef CONFIG_GACT_PROB
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if (gact->tcfg_ptype) {
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struct tc_gact_p p_opt = {
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.paction = gact->tcfg_paction,
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.pval = gact->tcfg_pval,
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.ptype = gact->tcfg_ptype,
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};
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if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
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goto nla_put_failure;
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}
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#endif
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tcf_tm_dump(&t, &gact->tcf_tm);
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if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
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goto nla_put_failure;
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spin_unlock_bh(&gact->tcf_lock);
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return skb->len;
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nla_put_failure:
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spin_unlock_bh(&gact->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_gact_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, gact_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_gact_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, gact_net_id);
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return tcf_idr_search(tn, a, index);
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}
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static size_t tcf_gact_get_fill_size(const struct tc_action *act)
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{
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size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
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#ifdef CONFIG_GACT_PROB
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if (to_gact(act)->tcfg_ptype)
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/* TCA_GACT_PROB */
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sz += nla_total_size(sizeof(struct tc_gact_p));
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#endif
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return sz;
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}
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static struct tc_action_ops act_gact_ops = {
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.kind = "gact",
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.id = TCA_ID_GACT,
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.owner = THIS_MODULE,
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.act = tcf_gact_act,
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.stats_update = tcf_gact_stats_update,
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.dump = tcf_gact_dump,
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.init = tcf_gact_init,
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.walk = tcf_gact_walker,
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.lookup = tcf_gact_search,
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.get_fill_size = tcf_gact_get_fill_size,
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.size = sizeof(struct tcf_gact),
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};
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static __net_init int gact_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, gact_net_id);
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return tc_action_net_init(net, tn, &act_gact_ops);
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}
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static void __net_exit gact_exit_net(struct list_head *net_list)
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{
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tc_action_net_exit(net_list, gact_net_id);
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}
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static struct pernet_operations gact_net_ops = {
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.init = gact_init_net,
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.exit_batch = gact_exit_net,
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.id = &gact_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(2002-4)");
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MODULE_DESCRIPTION("Generic Classifier actions");
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MODULE_LICENSE("GPL");
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static int __init gact_init_module(void)
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{
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#ifdef CONFIG_GACT_PROB
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pr_info("GACT probability on\n");
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#else
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pr_info("GACT probability NOT on\n");
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#endif
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return tcf_register_action(&act_gact_ops, &gact_net_ops);
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}
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static void __exit gact_cleanup_module(void)
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{
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tcf_unregister_action(&act_gact_ops, &gact_net_ops);
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}
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module_init(gact_init_module);
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module_exit(gact_cleanup_module);
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