![Dmytro Linkin](/assets/img/avatar_default.png)
Currently init call of all actions (except ipt) init their 'parm'
structure as a direct pointer to nla data in skb. This leads to race
condition when some of the filter actions were initialized successfully
(and were assigned with idr action index that was written directly
into nla data), but then were deleted and retried (due to following
action module missing or classifier-initiated retry), in which case
action init code tries to insert action to idr with index that was
assigned on previous iteration. During retry the index can be reused
by another action that was inserted concurrently, which causes
unintended action sharing between filters.
To fix described race condition, save action idr index to temporary
stack-allocated variable instead on nla data.
Fixes: 0190c1d452
("net: sched: atomically check-allocate action")
Signed-off-by: Dmytro Linkin <dmitrolin@mellanox.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
532 lines
12 KiB
C
532 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* net/sched/act_pedit.c Generic packet editor
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*
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* Authors: 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 <linux/slab.h>
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#include <net/netlink.h>
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#include <net/pkt_sched.h>
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#include <linux/tc_act/tc_pedit.h>
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#include <net/tc_act/tc_pedit.h>
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#include <uapi/linux/tc_act/tc_pedit.h>
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#include <net/pkt_cls.h>
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static unsigned int pedit_net_id;
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static struct tc_action_ops act_pedit_ops;
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static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
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[TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) },
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[TCA_PEDIT_KEYS_EX] = { .type = NLA_NESTED },
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};
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static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
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[TCA_PEDIT_KEY_EX_HTYPE] = { .type = NLA_U16 },
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[TCA_PEDIT_KEY_EX_CMD] = { .type = NLA_U16 },
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};
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static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
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u8 n)
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{
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struct tcf_pedit_key_ex *keys_ex;
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struct tcf_pedit_key_ex *k;
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const struct nlattr *ka;
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int err = -EINVAL;
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int rem;
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if (!nla || !n)
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return NULL;
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keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
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if (!keys_ex)
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return ERR_PTR(-ENOMEM);
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k = keys_ex;
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nla_for_each_nested(ka, nla, rem) {
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struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
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if (!n) {
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err = -EINVAL;
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goto err_out;
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}
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n--;
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if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
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err = -EINVAL;
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goto err_out;
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}
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err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
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ka, pedit_key_ex_policy,
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NULL);
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if (err)
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goto err_out;
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if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
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!tb[TCA_PEDIT_KEY_EX_CMD]) {
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err = -EINVAL;
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goto err_out;
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}
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k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
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k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
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if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
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k->cmd > TCA_PEDIT_CMD_MAX) {
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err = -EINVAL;
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goto err_out;
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}
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k++;
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}
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if (n) {
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err = -EINVAL;
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goto err_out;
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}
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return keys_ex;
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err_out:
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kfree(keys_ex);
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return ERR_PTR(err);
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}
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static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
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struct tcf_pedit_key_ex *keys_ex, int n)
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{
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struct nlattr *keys_start = nla_nest_start_noflag(skb,
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TCA_PEDIT_KEYS_EX);
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if (!keys_start)
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goto nla_failure;
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for (; n > 0; n--) {
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struct nlattr *key_start;
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key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
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if (!key_start)
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goto nla_failure;
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if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
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nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
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goto nla_failure;
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nla_nest_end(skb, key_start);
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keys_ex++;
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}
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nla_nest_end(skb, keys_start);
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return 0;
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nla_failure:
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nla_nest_cancel(skb, keys_start);
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return -EINVAL;
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}
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static int tcf_pedit_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, struct netlink_ext_ack *extack)
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{
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struct tc_action_net *tn = net_generic(net, pedit_net_id);
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struct nlattr *tb[TCA_PEDIT_MAX + 1];
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struct tcf_chain *goto_ch = NULL;
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struct tc_pedit_key *keys = NULL;
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struct tcf_pedit_key_ex *keys_ex;
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struct tc_pedit *parm;
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struct nlattr *pattr;
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struct tcf_pedit *p;
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int ret = 0, err;
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int ksize;
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u32 index;
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if (!nla) {
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NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
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return -EINVAL;
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}
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err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
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pedit_policy, NULL);
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if (err < 0)
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return err;
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pattr = tb[TCA_PEDIT_PARMS];
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if (!pattr)
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pattr = tb[TCA_PEDIT_PARMS_EX];
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if (!pattr) {
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NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
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return -EINVAL;
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}
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parm = nla_data(pattr);
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ksize = parm->nkeys * sizeof(struct tc_pedit_key);
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if (nla_len(pattr) < sizeof(*parm) + ksize) {
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NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
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return -EINVAL;
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}
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keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
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if (IS_ERR(keys_ex))
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return PTR_ERR(keys_ex);
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index = parm->index;
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err = tcf_idr_check_alloc(tn, &index, a, bind);
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if (!err) {
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if (!parm->nkeys) {
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tcf_idr_cleanup(tn, index);
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NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
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ret = -EINVAL;
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goto out_free;
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}
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ret = tcf_idr_create(tn, index, est, a,
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&act_pedit_ops, bind, false);
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if (ret) {
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tcf_idr_cleanup(tn, index);
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goto out_free;
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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)
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goto out_free;
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if (!ovr) {
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ret = -EEXIST;
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goto out_release;
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}
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} else {
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ret = err;
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goto out_free;
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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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ret = err;
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goto out_release;
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}
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p = to_pedit(*a);
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spin_lock_bh(&p->tcf_lock);
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if (ret == ACT_P_CREATED ||
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(p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
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keys = kmalloc(ksize, GFP_ATOMIC);
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if (!keys) {
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spin_unlock_bh(&p->tcf_lock);
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ret = -ENOMEM;
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goto put_chain;
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}
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kfree(p->tcfp_keys);
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p->tcfp_keys = keys;
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p->tcfp_nkeys = parm->nkeys;
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}
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memcpy(p->tcfp_keys, parm->keys, ksize);
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p->tcfp_flags = parm->flags;
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goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
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kfree(p->tcfp_keys_ex);
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p->tcfp_keys_ex = keys_ex;
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spin_unlock_bh(&p->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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tcf_idr_insert(tn, *a);
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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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out_release:
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tcf_idr_release(*a, bind);
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out_free:
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kfree(keys_ex);
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return ret;
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}
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static void tcf_pedit_cleanup(struct tc_action *a)
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{
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struct tcf_pedit *p = to_pedit(a);
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struct tc_pedit_key *keys = p->tcfp_keys;
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kfree(keys);
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kfree(p->tcfp_keys_ex);
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}
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static bool offset_valid(struct sk_buff *skb, int offset)
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{
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if (offset > 0 && offset > skb->len)
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return false;
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if (offset < 0 && -offset > skb_headroom(skb))
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return false;
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return true;
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}
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static int pedit_skb_hdr_offset(struct sk_buff *skb,
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enum pedit_header_type htype, int *hoffset)
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{
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int ret = -EINVAL;
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switch (htype) {
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case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
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if (skb_mac_header_was_set(skb)) {
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*hoffset = skb_mac_offset(skb);
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ret = 0;
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}
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break;
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case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
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case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
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case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
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*hoffset = skb_network_offset(skb);
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ret = 0;
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break;
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case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
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case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
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if (skb_transport_header_was_set(skb)) {
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*hoffset = skb_transport_offset(skb);
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ret = 0;
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}
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static int tcf_pedit_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_pedit *p = to_pedit(a);
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int i;
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if (skb_unclone(skb, GFP_ATOMIC))
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return p->tcf_action;
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spin_lock(&p->tcf_lock);
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tcf_lastuse_update(&p->tcf_tm);
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if (p->tcfp_nkeys > 0) {
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struct tc_pedit_key *tkey = p->tcfp_keys;
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struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
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enum pedit_header_type htype =
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TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
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enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
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for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
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u32 *ptr, hdata;
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int offset = tkey->off;
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int hoffset;
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u32 val;
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int rc;
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if (tkey_ex) {
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htype = tkey_ex->htype;
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cmd = tkey_ex->cmd;
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tkey_ex++;
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}
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rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
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if (rc) {
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pr_info("tc action pedit bad header type specified (0x%x)\n",
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htype);
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goto bad;
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}
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if (tkey->offmask) {
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u8 *d, _d;
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if (!offset_valid(skb, hoffset + tkey->at)) {
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pr_info("tc action pedit 'at' offset %d out of bounds\n",
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hoffset + tkey->at);
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goto bad;
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}
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d = skb_header_pointer(skb, hoffset + tkey->at,
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sizeof(_d), &_d);
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if (!d)
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goto bad;
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offset += (*d & tkey->offmask) >> tkey->shift;
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}
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if (offset % 4) {
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pr_info("tc action pedit offset must be on 32 bit boundaries\n");
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goto bad;
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}
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if (!offset_valid(skb, hoffset + offset)) {
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pr_info("tc action pedit offset %d out of bounds\n",
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hoffset + offset);
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goto bad;
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}
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ptr = skb_header_pointer(skb, hoffset + offset,
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sizeof(hdata), &hdata);
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if (!ptr)
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goto bad;
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/* just do it, baby */
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switch (cmd) {
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case TCA_PEDIT_KEY_EX_CMD_SET:
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val = tkey->val;
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break;
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case TCA_PEDIT_KEY_EX_CMD_ADD:
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val = (*ptr + tkey->val) & ~tkey->mask;
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break;
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default:
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pr_info("tc action pedit bad command (%d)\n",
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cmd);
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goto bad;
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}
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*ptr = ((*ptr & tkey->mask) ^ val);
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if (ptr == &hdata)
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skb_store_bits(skb, hoffset + offset, ptr, 4);
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}
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goto done;
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} else {
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WARN(1, "pedit BUG: index %d\n", p->tcf_index);
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}
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bad:
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p->tcf_qstats.overlimits++;
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done:
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bstats_update(&p->tcf_bstats, skb);
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spin_unlock(&p->tcf_lock);
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return p->tcf_action;
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}
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static int tcf_pedit_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_pedit *p = to_pedit(a);
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struct tc_pedit *opt;
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struct tcf_t t;
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int s;
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s = struct_size(opt, keys, p->tcfp_nkeys);
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/* netlink spinlocks held above us - must use ATOMIC */
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opt = kzalloc(s, GFP_ATOMIC);
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if (unlikely(!opt))
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return -ENOBUFS;
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spin_lock_bh(&p->tcf_lock);
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memcpy(opt->keys, p->tcfp_keys,
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p->tcfp_nkeys * sizeof(struct tc_pedit_key));
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opt->index = p->tcf_index;
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opt->nkeys = p->tcfp_nkeys;
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opt->flags = p->tcfp_flags;
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opt->action = p->tcf_action;
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opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
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opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
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if (p->tcfp_keys_ex) {
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if (tcf_pedit_key_ex_dump(skb,
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p->tcfp_keys_ex,
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p->tcfp_nkeys))
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goto nla_put_failure;
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if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
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goto nla_put_failure;
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} else {
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if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
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goto nla_put_failure;
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}
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tcf_tm_dump(&t, &p->tcf_tm);
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if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
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goto nla_put_failure;
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spin_unlock_bh(&p->tcf_lock);
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kfree(opt);
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return skb->len;
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nla_put_failure:
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spin_unlock_bh(&p->tcf_lock);
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nlmsg_trim(skb, b);
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kfree(opt);
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return -1;
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}
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static int tcf_pedit_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, pedit_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_pedit_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, pedit_net_id);
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return tcf_idr_search(tn, a, index);
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}
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static struct tc_action_ops act_pedit_ops = {
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.kind = "pedit",
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.id = TCA_ID_PEDIT,
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.owner = THIS_MODULE,
|
|
.act = tcf_pedit_act,
|
|
.dump = tcf_pedit_dump,
|
|
.cleanup = tcf_pedit_cleanup,
|
|
.init = tcf_pedit_init,
|
|
.walk = tcf_pedit_walker,
|
|
.lookup = tcf_pedit_search,
|
|
.size = sizeof(struct tcf_pedit),
|
|
};
|
|
|
|
static __net_init int pedit_init_net(struct net *net)
|
|
{
|
|
struct tc_action_net *tn = net_generic(net, pedit_net_id);
|
|
|
|
return tc_action_net_init(tn, &act_pedit_ops);
|
|
}
|
|
|
|
static void __net_exit pedit_exit_net(struct list_head *net_list)
|
|
{
|
|
tc_action_net_exit(net_list, pedit_net_id);
|
|
}
|
|
|
|
static struct pernet_operations pedit_net_ops = {
|
|
.init = pedit_init_net,
|
|
.exit_batch = pedit_exit_net,
|
|
.id = &pedit_net_id,
|
|
.size = sizeof(struct tc_action_net),
|
|
};
|
|
|
|
MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
|
|
MODULE_DESCRIPTION("Generic Packet Editor actions");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static int __init pedit_init_module(void)
|
|
{
|
|
return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
|
|
}
|
|
|
|
static void __exit pedit_cleanup_module(void)
|
|
{
|
|
tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
|
|
}
|
|
|
|
module_init(pedit_init_module);
|
|
module_exit(pedit_cleanup_module);
|