![WANG Cong](/assets/img/avatar_default.png)
Currently tc actions are stored in a per-module hashtable, therefore are visible to all network namespaces. This is probably the last part of the tc subsystem which is not aware of netns now. This patch makes them per-netns, several tc action API's need to be adjusted for this. The tc action API code is ugly due to historical reasons, we need to refactor that code in the future. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
343 lines
7.4 KiB
C
343 lines
7.4 KiB
C
/*
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* Stateless NAT actions
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*
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* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*/
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/string.h>
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#include <linux/tc_act/tc_nat.h>
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#include <net/act_api.h>
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#include <net/icmp.h>
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#include <net/ip.h>
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#include <net/netlink.h>
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#include <net/tc_act/tc_nat.h>
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#include <net/tcp.h>
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#include <net/udp.h>
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#define NAT_TAB_MASK 15
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static int nat_net_id;
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static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
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[TCA_NAT_PARMS] = { .len = sizeof(struct tc_nat) },
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};
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static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
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struct tc_action *a, int ovr, int bind)
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{
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struct tc_action_net *tn = net_generic(net, nat_net_id);
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struct nlattr *tb[TCA_NAT_MAX + 1];
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struct tc_nat *parm;
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int ret = 0, err;
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struct tcf_nat *p;
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if (nla == NULL)
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return -EINVAL;
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err = nla_parse_nested(tb, TCA_NAT_MAX, nla, nat_policy);
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if (err < 0)
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return err;
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if (tb[TCA_NAT_PARMS] == NULL)
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return -EINVAL;
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parm = nla_data(tb[TCA_NAT_PARMS]);
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if (!tcf_hash_check(tn, parm->index, a, bind)) {
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ret = tcf_hash_create(tn, parm->index, est, a,
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sizeof(*p), bind, false);
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if (ret)
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return ret;
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ret = ACT_P_CREATED;
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} else {
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if (bind)
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return 0;
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tcf_hash_release(a, bind);
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if (!ovr)
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return -EEXIST;
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}
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p = to_tcf_nat(a);
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spin_lock_bh(&p->tcf_lock);
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p->old_addr = parm->old_addr;
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p->new_addr = parm->new_addr;
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p->mask = parm->mask;
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p->flags = parm->flags;
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p->tcf_action = parm->action;
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spin_unlock_bh(&p->tcf_lock);
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if (ret == ACT_P_CREATED)
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tcf_hash_insert(tn, a);
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return ret;
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}
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static int tcf_nat(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_nat *p = a->priv;
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struct iphdr *iph;
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__be32 old_addr;
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__be32 new_addr;
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__be32 mask;
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__be32 addr;
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int egress;
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int action;
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int ihl;
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int noff;
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spin_lock(&p->tcf_lock);
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p->tcf_tm.lastuse = jiffies;
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old_addr = p->old_addr;
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new_addr = p->new_addr;
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mask = p->mask;
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egress = p->flags & TCA_NAT_FLAG_EGRESS;
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action = p->tcf_action;
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bstats_update(&p->tcf_bstats, skb);
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spin_unlock(&p->tcf_lock);
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if (unlikely(action == TC_ACT_SHOT))
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goto drop;
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noff = skb_network_offset(skb);
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if (!pskb_may_pull(skb, sizeof(*iph) + noff))
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goto drop;
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iph = ip_hdr(skb);
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if (egress)
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addr = iph->saddr;
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else
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addr = iph->daddr;
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if (!((old_addr ^ addr) & mask)) {
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if (skb_try_make_writable(skb, sizeof(*iph) + noff))
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goto drop;
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new_addr &= mask;
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new_addr |= addr & ~mask;
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/* Rewrite IP header */
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iph = ip_hdr(skb);
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if (egress)
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iph->saddr = new_addr;
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else
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iph->daddr = new_addr;
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csum_replace4(&iph->check, addr, new_addr);
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} else if ((iph->frag_off & htons(IP_OFFSET)) ||
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iph->protocol != IPPROTO_ICMP) {
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goto out;
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}
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ihl = iph->ihl * 4;
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/* It would be nice to share code with stateful NAT. */
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switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
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case IPPROTO_TCP:
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{
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struct tcphdr *tcph;
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if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
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skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff))
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goto drop;
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tcph = (void *)(skb_network_header(skb) + ihl);
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inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr,
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true);
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break;
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}
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case IPPROTO_UDP:
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{
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struct udphdr *udph;
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if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
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skb_try_make_writable(skb, ihl + sizeof(*udph) + noff))
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goto drop;
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udph = (void *)(skb_network_header(skb) + ihl);
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if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
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inet_proto_csum_replace4(&udph->check, skb, addr,
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new_addr, true);
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if (!udph->check)
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udph->check = CSUM_MANGLED_0;
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}
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break;
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}
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case IPPROTO_ICMP:
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{
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struct icmphdr *icmph;
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if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff))
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goto drop;
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icmph = (void *)(skb_network_header(skb) + ihl);
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if ((icmph->type != ICMP_DEST_UNREACH) &&
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(icmph->type != ICMP_TIME_EXCEEDED) &&
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(icmph->type != ICMP_PARAMETERPROB))
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break;
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if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) +
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noff))
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goto drop;
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icmph = (void *)(skb_network_header(skb) + ihl);
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iph = (void *)(icmph + 1);
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if (egress)
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addr = iph->daddr;
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else
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addr = iph->saddr;
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if ((old_addr ^ addr) & mask)
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break;
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if (skb_try_make_writable(skb, ihl + sizeof(*icmph) +
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sizeof(*iph) + noff))
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goto drop;
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icmph = (void *)(skb_network_header(skb) + ihl);
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iph = (void *)(icmph + 1);
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new_addr &= mask;
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new_addr |= addr & ~mask;
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/* XXX Fix up the inner checksums. */
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if (egress)
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iph->daddr = new_addr;
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else
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iph->saddr = new_addr;
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inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
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false);
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break;
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}
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default:
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break;
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}
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out:
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return action;
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drop:
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spin_lock(&p->tcf_lock);
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p->tcf_qstats.drops++;
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spin_unlock(&p->tcf_lock);
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return TC_ACT_SHOT;
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}
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static int tcf_nat_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_nat *p = a->priv;
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struct tc_nat opt = {
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.old_addr = p->old_addr,
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.new_addr = p->new_addr,
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.mask = p->mask,
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.flags = p->flags,
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.index = p->tcf_index,
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.action = p->tcf_action,
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.refcnt = p->tcf_refcnt - ref,
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.bindcnt = p->tcf_bindcnt - bind,
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};
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struct tcf_t t;
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if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
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goto nla_put_failure;
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t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
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t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
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t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
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if (nla_put(skb, TCA_NAT_TM, sizeof(t), &t))
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goto nla_put_failure;
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return skb->len;
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nla_put_failure:
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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_nat_walker(struct net *net, struct sk_buff *skb,
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struct netlink_callback *cb, int type,
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struct tc_action *a)
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{
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struct tc_action_net *tn = net_generic(net, nat_net_id);
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return tcf_generic_walker(tn, skb, cb, type, a);
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}
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static int tcf_nat_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, nat_net_id);
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return tcf_hash_search(tn, a, index);
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}
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static struct tc_action_ops act_nat_ops = {
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.kind = "nat",
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.type = TCA_ACT_NAT,
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.owner = THIS_MODULE,
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.act = tcf_nat,
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.dump = tcf_nat_dump,
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.init = tcf_nat_init,
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.walk = tcf_nat_walker,
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.lookup = tcf_nat_search,
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};
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static __net_init int nat_init_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, nat_net_id);
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return tc_action_net_init(tn, &act_nat_ops, NAT_TAB_MASK);
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}
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static void __net_exit nat_exit_net(struct net *net)
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{
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struct tc_action_net *tn = net_generic(net, nat_net_id);
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tc_action_net_exit(tn);
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}
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static struct pernet_operations nat_net_ops = {
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.init = nat_init_net,
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.exit = nat_exit_net,
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.id = &nat_net_id,
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.size = sizeof(struct tc_action_net),
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};
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MODULE_DESCRIPTION("Stateless NAT actions");
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MODULE_LICENSE("GPL");
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static int __init nat_init_module(void)
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{
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return tcf_register_action(&act_nat_ops, &nat_net_ops);
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}
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static void __exit nat_cleanup_module(void)
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{
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tcf_unregister_action(&act_nat_ops, &nat_net_ops);
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}
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module_init(nat_init_module);
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module_exit(nat_cleanup_module);
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