Release 4.11 net/ipv4/netfilter/ipt_ECN.c

/* iptables module for the IPv4 and TCP ECN bits, Version 1.5
 *
 * (C) 2002 by Harald Welte <laforge@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/in.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/ip.h>
#include <linux/tcp.h>
#include <net/checksum.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ECN.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_DESCRIPTION("Xtables: Explicit Congestion Notification (ECN) flag modification");

/* set ECT codepoint from IP header.
 *      return false if there was an error. */

static inline bool

set_ect_ip(struct sk_buff *skb, const struct ipt_ECN_info *einfo)
{
	struct iphdr *iph = ip_hdr(skb);

	if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
		__u8 oldtos;
		if (!skb_make_writable(skb, sizeof(struct iphdr)))
			return false;
		iph = ip_hdr(skb);
		oldtos = iph->tos;
		iph->tos &= ~IPT_ECN_IP_MASK;
		iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
		csum_replace2(&iph->check, htons(oldtos), htons(iph->tos));
	}
	return true;
}

Contributors
Person
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Commits
CommitProp
Harald Welte
71
57.72%
2
20.00%
Patrick McHardy
25
20.33%
3
30.00%
Rusty Russell
8
6.50%
1
10.00%
Al Viro
6
4.88%
1
10.00%
Arnaldo Carvalho de Melo
6
4.88%
1
10.00%
Herbert Xu
4
3.25%
1
10.00%
Jan Engelhardt
3
2.44%
1
10.00%
Total
123
100.00%
10
100.00%

/* Return false if there was an error. */

static inline bool

set_ect_tcp(struct sk_buff *skb, const struct ipt_ECN_info *einfo)
{
	struct tcphdr _tcph, *tcph;
	__be16 oldval;

	/* Not enough header? */
	tcph = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
	if (!tcph)
		return false;

	if ((!(einfo->operation & IPT_ECN_OP_SET_ECE) ||
	     tcph->ece == einfo->proto.tcp.ece) &&
	    (!(einfo->operation & IPT_ECN_OP_SET_CWR) ||
	     tcph->cwr == einfo->proto.tcp.cwr))
		return true;

	if (!skb_make_writable(skb, ip_hdrlen(skb) + sizeof(*tcph)))
		return false;
	tcph = (void *)ip_hdr(skb) + ip_hdrlen(skb);

	oldval = ((__be16 *)tcph)[6];
	if (einfo->operation & IPT_ECN_OP_SET_ECE)
		tcph->ece = einfo->proto.tcp.ece;
	if (einfo->operation & IPT_ECN_OP_SET_CWR)
		tcph->cwr = einfo->proto.tcp.cwr;

	inet_proto_csum_replace2(&tcph->check, skb,
				 oldval, ((__be16 *)tcph)[6], false);
	return true;
}

Contributors
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CommitProp
Rusty Russell
88
38.77%
2
11.76%
Harald Welte
72
31.72%
2
11.76%
Patrick McHardy
16
7.05%
3
17.65%
David S. Miller
15
6.61%
1
5.88%
Arnaldo Carvalho de Melo
12
5.29%
2
11.76%
Herbert Xu
8
3.52%
1
5.88%
Al Viro
6
2.64%
2
11.76%
Jan Engelhardt
5
2.20%
1
5.88%
James Morris
3
1.32%
1
5.88%
André Goddard Rosa
1
0.44%
1
5.88%
Tom Herbert
1
0.44%
1
5.88%
Total
227
100.00%
17
100.00%


static unsigned int

ecn_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct ipt_ECN_info *einfo = par->targinfo;

	if (einfo->operation & IPT_ECN_OP_SET_IP)
		if (!set_ect_ip(skb, einfo))
			return NF_DROP;

	if (einfo->operation & (IPT_ECN_OP_SET_ECE | IPT_ECN_OP_SET_CWR) &&
	    ip_hdr(skb)->protocol == IPPROTO_TCP)
		if (!set_ect_tcp(skb, einfo))
			return NF_DROP;

	return XT_CONTINUE;
}

Contributors
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Tokens
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CommitProp
Harald Welte
59
68.60%
1
12.50%
Rusty Russell
14
16.28%
1
12.50%
Jan Engelhardt
6
6.98%
4
50.00%
Herbert Xu
4
4.65%
1
12.50%
Arnaldo Carvalho de Melo
3
3.49%
1
12.50%
Total
86
100.00%
8
100.00%



static int ecn_tg_check(const struct xt_tgchk_param *par)
{
	const struct ipt_ECN_info *einfo = par->targinfo;
	const struct ipt_entry *e = par->entryinfo;

	if (einfo->operation & IPT_ECN_OP_MASK) {
		pr_info("unsupported ECN operation %x\n", einfo->operation);
		return -EINVAL;
	}
	if (einfo->ip_ect & ~IPT_ECN_IP_MASK) {
		pr_info("new ECT codepoint %x out of mask\n", einfo->ip_ect);
		return -EINVAL;
	}
	if ((einfo->operation & (IPT_ECN_OP_SET_ECE|IPT_ECN_OP_SET_CWR)) &&
	    (e->ip.proto != IPPROTO_TCP || (e->ip.invflags & XT_INV_PROTO))) {
		pr_info("cannot use TCP operations on a non-tcp rule\n");
		return -EINVAL;
	}
	return 0;
}

Contributors
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CommitProp
Harald Welte
91
71.65%
2
20.00%
Jan Engelhardt
23
18.11%
6
60.00%
Rusty Russell
11
8.66%
1
10.00%
Patrick McHardy
2
1.57%
1
10.00%
Total
127
100.00%
10
100.00%


static struct xt_target ecn_tg_reg __read_mostly = {
	.name		= "ECN",
	.family		= NFPROTO_IPV4,
	.target		= ecn_tg,
	.targetsize	= sizeof(struct ipt_ECN_info),
	.table		= "mangle",
	.checkentry	= ecn_tg_check,
	.me		= THIS_MODULE,
};



static int __init ecn_tg_init(void)
{
	return xt_register_target(&ecn_tg_reg);
}

Contributors
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CommitProp
Harald Welte
12
75.00%
1
25.00%
Jan Engelhardt
3
18.75%
2
50.00%
Daniele Bellucci
1
6.25%
1
25.00%
Total
16
100.00%
4
100.00%



static void __exit ecn_tg_exit(void)
{
	xt_unregister_target(&ecn_tg_reg);
}

Contributors
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Tokens
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Commits
CommitProp
Harald Welte
12
80.00%
1
33.33%
Jan Engelhardt
3
20.00%
2
66.67%
Total
15
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3
100.00%


module_init(ecn_tg_init);

module_exit(ecn_tg_exit);
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Harald Welte
370
52.41%
4
10.53%
Rusty Russell
121
17.14%
3
7.89%
Jan Engelhardt
70
9.92%
11
28.95%
Patrick McHardy
59
8.36%
9
23.68%
Arnaldo Carvalho de Melo
24
3.40%
2
5.26%
Herbert Xu
16
2.27%
1
2.63%
David S. Miller
15
2.12%
1
2.63%
Art Haas
13
1.84%
1
2.63%
Al Viro
12
1.70%
2
5.26%
James Morris
3
0.42%
1
2.63%
Tom Herbert
1
0.14%
1
2.63%
André Goddard Rosa
1
0.14%
1
2.63%
Daniele Bellucci
1
0.14%
1
2.63%
Total
706
100.00%
38
100.00%
Directory: net/ipv4/netfilter

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