Release 4.14 net/sched/act_nat.c

/*
 * Stateless NAT actions
 *
 * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/tc_act/tc_nat.h>
#include <net/act_api.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/netlink.h>
#include <net/tc_act/tc_nat.h>
#include <net/tcp.h>
#include <net/udp.h>



static unsigned int nat_net_id;

static struct tc_action_ops act_nat_ops;


static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
	[TCA_NAT_PARMS]	= { .len = sizeof(struct tc_nat) },
};



static int tcf_nat_init(struct net *net, struct nlattr *nla, struct nlattr *est,
			struct tc_action **a, int ovr, int bind)
{
	struct tc_action_net *tn = net_generic(net, nat_net_id);
	struct nlattr *tb[TCA_NAT_MAX + 1];
	struct tc_nat *parm;
	int ret = 0, err;
	struct tcf_nat *p;

	if (nla == NULL)
		return -EINVAL;

	err = nla_parse_nested(tb, TCA_NAT_MAX, nla, nat_policy, NULL);
	if (err < 0)
		return err;

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

	if (!tcf_idr_check(tn, parm->index, a, bind)) {
		ret = tcf_idr_create(tn, parm->index, est, a,
				     &act_nat_ops, bind, false);
		if (ret)
			return ret;
		ret = ACT_P_CREATED;
	} else {
		if (bind)
			return 0;
		tcf_idr_release(*a, bind);
		if (!ovr)
			return -EEXIST;
	}
	p = to_tcf_nat(*a);

	spin_lock_bh(&p->tcf_lock);
	p->old_addr = parm->old_addr;
	p->new_addr = parm->new_addr;
	p->mask = parm->mask;
	p->flags = parm->flags;

	p->tcf_action = parm->action;
	spin_unlock_bh(&p->tcf_lock);

	if (ret == ACT_P_CREATED)
		tcf_idr_insert(tn, *a);

	return ret;
}

Contributors
Person
Tokens
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CommitProp
Herbert Xu
201
69.79%
1
7.69%
Américo Wang
33
11.46%
4
30.77%
Patrick McHardy
26
9.03%
3
23.08%
Jamal Hadi Salim
15
5.21%
1
7.69%
Benjamin LaHaise
5
1.74%
1
7.69%
Chris Mi
4
1.39%
1
7.69%
Eric Dumazet
2
0.69%
1
7.69%
Johannes Berg
2
0.69%
1
7.69%
Total
288
100.00%
13
100.00%



static int tcf_nat(struct sk_buff *skb, const struct tc_action *a,
		   struct tcf_result *res)
{
	struct tcf_nat *p = to_tcf_nat(a);
	struct iphdr *iph;
	__be32 old_addr;
	__be32 new_addr;
	__be32 mask;
	__be32 addr;
	int egress;
	int action;
	int ihl;
	int noff;

	spin_lock(&p->tcf_lock);

	tcf_lastuse_update(&p->tcf_tm);
	old_addr = p->old_addr;
	new_addr = p->new_addr;
	mask = p->mask;
	egress = p->flags & TCA_NAT_FLAG_EGRESS;
	action = p->tcf_action;

	bstats_update(&p->tcf_bstats, skb);

	spin_unlock(&p->tcf_lock);

	if (unlikely(action == TC_ACT_SHOT))
		goto drop;

	noff = skb_network_offset(skb);
	if (!pskb_may_pull(skb, sizeof(*iph) + noff))
		goto drop;

	iph = ip_hdr(skb);

	if (egress)
		addr = iph->saddr;
	else
		addr = iph->daddr;

	if (!((old_addr ^ addr) & mask)) {
		if (skb_try_make_writable(skb, sizeof(*iph) + noff))
			goto drop;

		new_addr &= mask;
		new_addr |= addr & ~mask;

		/* Rewrite IP header */
		iph = ip_hdr(skb);
		if (egress)
			iph->saddr = new_addr;
		else
			iph->daddr = new_addr;

		csum_replace4(&iph->check, addr, new_addr);
	} else if ((iph->frag_off & htons(IP_OFFSET)) ||
		   iph->protocol != IPPROTO_ICMP) {
		goto out;
	}

	ihl = iph->ihl * 4;

	/* It would be nice to share code with stateful NAT. */
	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
	case IPPROTO_TCP:
	{
		struct tcphdr *tcph;

		if (!pskb_may_pull(skb, ihl + sizeof(*tcph) + noff) ||
		    skb_try_make_writable(skb, ihl + sizeof(*tcph) + noff))
			goto drop;

		tcph = (void *)(skb_network_header(skb) + ihl);
		inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr,
					 true);
		break;
	}
	case IPPROTO_UDP:
	{
		struct udphdr *udph;

		if (!pskb_may_pull(skb, ihl + sizeof(*udph) + noff) ||
		    skb_try_make_writable(skb, ihl + sizeof(*udph) + noff))
			goto drop;

		udph = (void *)(skb_network_header(skb) + ihl);
		if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
			inet_proto_csum_replace4(&udph->check, skb, addr,
						 new_addr, true);
			if (!udph->check)
				udph->check = CSUM_MANGLED_0;
		}
		break;
	}
	case IPPROTO_ICMP:
	{
		struct icmphdr *icmph;

		if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + noff))
			goto drop;

		icmph = (void *)(skb_network_header(skb) + ihl);

		if ((icmph->type != ICMP_DEST_UNREACH) &&
		    (icmph->type != ICMP_TIME_EXCEEDED) &&
		    (icmph->type != ICMP_PARAMETERPROB))
			break;

		if (!pskb_may_pull(skb, ihl + sizeof(*icmph) + sizeof(*iph) +
					noff))
			goto drop;

		icmph = (void *)(skb_network_header(skb) + ihl);
		iph = (void *)(icmph + 1);
		if (egress)
			addr = iph->daddr;
		else
			addr = iph->saddr;

		if ((old_addr ^ addr) & mask)
			break;

		if (skb_try_make_writable(skb, ihl + sizeof(*icmph) +
					  sizeof(*iph) + noff))
			goto drop;

		icmph = (void *)(skb_network_header(skb) + ihl);
		iph = (void *)(icmph + 1);

		new_addr &= mask;
		new_addr |= addr & ~mask;

		/* XXX Fix up the inner checksums. */
		if (egress)
			iph->daddr = new_addr;
		else
			iph->saddr = new_addr;

		inet_proto_csum_replace4(&icmph->checksum, skb, addr, new_addr,
					 false);
		break;
	}
	default:
		break;
	}

out:
	return action;

drop:
	spin_lock(&p->tcf_lock);
	p->tcf_qstats.drops++;
	spin_unlock(&p->tcf_lock);
	return TC_ACT_SHOT;
}

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Herbert Xu
676
85.03%
1
7.69%
Changli Gao
95
11.95%
4
30.77%
Eric Dumazet
5
0.63%
2
15.38%
Jamal Hadi Salim
4
0.50%
1
7.69%
Daniel Borkmann
4
0.50%
1
7.69%
Patrick McHardy
4
0.50%
1
7.69%
Tom Herbert
3
0.38%
1
7.69%
Américo Wang
3
0.38%
1
7.69%
Jussi Kivilinna
1
0.13%
1
7.69%
Total
795
100.00%
13
100.00%



static int tcf_nat_dump(struct sk_buff *skb, struct tc_action *a,
			int bind, int ref)
{
	unsigned char *b = skb_tail_pointer(skb);
	struct tcf_nat *p = to_tcf_nat(a);
	struct tc_nat opt = {
		.old_addr = p->old_addr,
		.new_addr = p->new_addr,
		.mask     = p->mask,
		.flags    = p->flags,

		.index    = p->tcf_index,
		.action   = p->tcf_action,
		.refcnt   = p->tcf_refcnt - ref,
		.bindcnt  = p->tcf_bindcnt - bind,
        };
	struct tcf_t t;

	if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
		goto nla_put_failure;

	tcf_tm_dump(&t, &p->tcf_tm);
	if (nla_put_64bit(skb, TCA_NAT_TM, sizeof(t), &t, TCA_NAT_PAD))
		goto nla_put_failure;

	return skb->len;

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

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CommitProp
Herbert Xu
130
71.04%
1
11.11%
Eric Dumazet
15
8.20%
1
11.11%
David S. Miller
13
7.10%
1
11.11%
Changli Gao
13
7.10%
1
11.11%
Jamal Hadi Salim
5
2.73%
2
22.22%
Américo Wang
3
1.64%
1
11.11%
Nicolas Dichtel
3
1.64%
1
11.11%
Patrick McHardy
1
0.55%
1
11.11%
Total
183
100.00%
9
100.00%



static int tcf_nat_walker(struct net *net, struct sk_buff *skb,
			  struct netlink_callback *cb, int type,
			  const struct tc_action_ops *ops)
{
	struct tc_action_net *tn = net_generic(net, nat_net_id);

	return tcf_generic_walker(tn, skb, cb, type, ops);
}

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2
100.00%



static int tcf_nat_search(struct net *net, struct tc_action **a, u32 index)
{
	struct tc_action_net *tn = net_generic(net, nat_net_id);

	return tcf_idr_search(tn, a, index);
}

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Américo Wang
41
97.62%
2
66.67%
Chris Mi
1
2.38%
1
33.33%
Total
42
100.00%
3
100.00%


static struct tc_action_ops act_nat_ops = {
	.kind		=	"nat",
	.type		=	TCA_ACT_NAT,
	.owner		=	THIS_MODULE,
	.act		=	tcf_nat,
	.dump		=	tcf_nat_dump,
	.init		=	tcf_nat_init,
	.walk		=	tcf_nat_walker,
	.lookup		=	tcf_nat_search,
	.size		=	sizeof(struct tcf_nat),
};



static __net_init int nat_init_net(struct net *net)
{
	struct tc_action_net *tn = net_generic(net, nat_net_id);

	return tc_action_net_init(tn, &act_nat_ops);
}

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33
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1
100.00%



static void __net_exit nat_exit_net(struct net *net)
{
	struct tc_action_net *tn = net_generic(net, nat_net_id);

	tc_action_net_exit(tn);
}

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static struct pernet_operations nat_net_ops = {
	.init = nat_init_net,
	.exit = nat_exit_net,
	.id   = &nat_net_id,
	.size = sizeof(struct tc_action_net),
};

MODULE_DESCRIPTION("Stateless NAT actions");
MODULE_LICENSE("GPL");



static int __init nat_init_module(void)
{
	return tcf_register_action(&act_nat_ops, &nat_net_ops);
}

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Herbert Xu
16
84.21%
1
33.33%
Américo Wang
3
15.79%
2
66.67%
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19
100.00%
3
100.00%



static void __exit nat_cleanup_module(void)
{
	tcf_unregister_action(&act_nat_ops, &nat_net_ops);
}

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15
83.33%
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16.67%
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2
100.00%


module_init(nat_init_module);

module_exit(nat_cleanup_module);
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Herbert Xu
1149
69.05%
1
3.03%
Américo Wang
264
15.87%
5
15.15%
Changli Gao
108
6.49%
5
15.15%
Patrick McHardy
59
3.55%
4
12.12%
Jamal Hadi Salim
25
1.50%
5
15.15%
Eric Dumazet
22
1.32%
4
12.12%
David S. Miller
13
0.78%
1
3.03%
Chris Mi
5
0.30%
1
3.03%
Benjamin LaHaise
5
0.30%
1
3.03%
Daniel Borkmann
4
0.24%
1
3.03%
Tom Herbert
3
0.18%
1
3.03%
Nicolas Dichtel
3
0.18%
1
3.03%
Johannes Berg
2
0.12%
1
3.03%
Alexey Dobriyan
1
0.06%
1
3.03%
Jussi Kivilinna
1
0.06%
1
3.03%
Total
1664
100.00%
33
100.00%
Directory: net/sched

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