libxt_ecn.c revision 98e1769b65b71989e3f16b25529b40f374aef323 
1/* Shared library add-on to iptables for ECN matching
2 *
3 * (C) 2002 by Harald Welte <laforge@netfilter.org>
4 * (C) 2011 by Patrick McHardy <kaber@trash.net>
5 *
6 * This program is distributed under the terms of GNU GPL v2, 1991
7 *
8 * libipt_ecn.c borrowed heavily from libipt_dscp.c
9 *
10 */
11#include <stdio.h>
12#include <xtables.h>
13#include <linux/netfilter/xt_ecn.h>
14
15enum {
16	O_ECN_TCP_CWR = 0,
17	O_ECN_TCP_ECE,
18	O_ECN_IP_ECT,
19};
20
21static void ecn_help(void)
22{
23	printf(
24"ECN match options\n"
25"[!] --ecn-tcp-cwr 		Match CWR bit of TCP header\n"
26"[!] --ecn-tcp-ece		Match ECE bit of TCP header\n"
27"[!] --ecn-ip-ect [0..3]	Match ECN codepoint in IPv4/IPv6 header\n");
28}
29
30static const struct xt_option_entry ecn_opts[] = {
31	{.name = "ecn-tcp-cwr", .id = O_ECN_TCP_CWR, .type = XTTYPE_NONE,
32	 .flags = XTOPT_INVERT},
33	{.name = "ecn-tcp-ece", .id = O_ECN_TCP_ECE, .type = XTTYPE_NONE,
34	 .flags = XTOPT_INVERT},
35	{.name = "ecn-ip-ect", .id = O_ECN_IP_ECT, .type = XTTYPE_UINT8,
36	 .min = 0, .max = 3, .flags = XTOPT_INVERT},
37	XTOPT_TABLEEND,
38};
39
40static void ecn_parse(struct xt_option_call *cb)
41{
42	struct xt_ecn_info *einfo = cb->data;
43
44	xtables_option_parse(cb);
45	switch (cb->entry->id) {
46	case O_ECN_TCP_CWR:
47		einfo->operation |= XT_ECN_OP_MATCH_CWR;
48		if (cb->invert)
49			einfo->invert |= XT_ECN_OP_MATCH_CWR;
50		break;
51	case O_ECN_TCP_ECE:
52		einfo->operation |= XT_ECN_OP_MATCH_ECE;
53		if (cb->invert)
54			einfo->invert |= XT_ECN_OP_MATCH_ECE;
55		break;
56	case O_ECN_IP_ECT:
57		if (cb->invert)
58			einfo->invert |= XT_ECN_OP_MATCH_IP;
59		einfo->operation |= XT_ECN_OP_MATCH_IP;
60		einfo->ip_ect = cb->val.u8;
61		break;
62	}
63}
64
65static void ecn_check(struct xt_fcheck_call *cb)
66{
67	if (cb->xflags == 0)
68		xtables_error(PARAMETER_PROBLEM,
69		           "ECN match: some option required");
70}
71
72static void ecn_print(const void *ip, const struct xt_entry_match *match,
73                      int numeric)
74{
75	const struct xt_ecn_info *einfo =
76		(const struct xt_ecn_info *)match->data;
77
78	printf(" ECN match");
79
80	if (einfo->operation & XT_ECN_OP_MATCH_ECE) {
81		printf(" %sECE",
82		       (einfo->invert & XT_ECN_OP_MATCH_ECE) ? "!" : "");
83	}
84
85	if (einfo->operation & XT_ECN_OP_MATCH_CWR) {
86		printf(" %sCWR",
87		       (einfo->invert & XT_ECN_OP_MATCH_CWR) ? "!" : "");
88	}
89
90	if (einfo->operation & XT_ECN_OP_MATCH_IP) {
91		printf(" %sECT=%d",
92		       (einfo->invert & XT_ECN_OP_MATCH_IP) ? "!" : "",
93		       einfo->ip_ect);
94	}
95}
96
97static void ecn_save(const void *ip, const struct xt_entry_match *match)
98{
99	const struct xt_ecn_info *einfo =
100		(const struct xt_ecn_info *)match->data;
101
102	if (einfo->operation & XT_ECN_OP_MATCH_ECE) {
103		if (einfo->invert & XT_ECN_OP_MATCH_ECE)
104			printf(" !");
105		printf(" --ecn-tcp-ece");
106	}
107
108	if (einfo->operation & XT_ECN_OP_MATCH_CWR) {
109		if (einfo->invert & XT_ECN_OP_MATCH_CWR)
110			printf(" !");
111		printf(" --ecn-tcp-cwr");
112	}
113
114	if (einfo->operation & XT_ECN_OP_MATCH_IP) {
115		if (einfo->invert & XT_ECN_OP_MATCH_IP)
116			printf(" !");
117		printf(" --ecn-ip-ect %d", einfo->ip_ect);
118	}
119}
120
121static struct xtables_match ecn_mt_reg = {
122	.name          = "ecn",
123	.version       = XTABLES_VERSION,
124	.family        = NFPROTO_UNSPEC,
125	.size          = XT_ALIGN(sizeof(struct xt_ecn_info)),
126	.userspacesize = XT_ALIGN(sizeof(struct xt_ecn_info)),
127	.help          = ecn_help,
128	.print         = ecn_print,
129	.save          = ecn_save,
130	.x6_parse      = ecn_parse,
131	.x6_fcheck     = ecn_check,
132	.x6_options    = ecn_opts,
133};
134
135void _init(void)
136{
137	xtables_register_match(&ecn_mt_reg);
138}
139