libxt_TOS.c revision 73866357e4a7a0fdc1b293bf8863fee2bd56da9e 
1/*
2 * Shared library add-on to iptables to add TOS target support
3 *
4 * Copyright © CC Computer Consultants GmbH, 2007
5 * Contact: Jan Engelhardt <jengelh@computergmbh.de>
6 */
7#include <getopt.h>
8#include <stdbool.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <string.h>
12#include <netinet/in.h>
13
14#include <xtables.h>
15#include <linux/netfilter/xt_DSCP.h>
16#include "tos_values.c"
17
18struct ipt_tos_target_info {
19	uint8_t tos;
20};
21
22enum {
23	FLAG_TOS = 1 << 0,
24};
25
26static const struct option tos_tg_opts_v0[] = {
27	{.name = "set-tos", .has_arg = true, .val = '='},
28	XT_GETOPT_TABLEEND,
29};
30
31static const struct option tos_tg_opts[] = {
32	{.name = "set-tos", .has_arg = true, .val = '='},
33	{.name = "and-tos", .has_arg = true, .val = '&'},
34	{.name = "or-tos",  .has_arg = true, .val = '|'},
35	{.name = "xor-tos", .has_arg = true, .val = '^'},
36	XT_GETOPT_TABLEEND,
37};
38
39static void tos_tg_help_v0(void)
40{
41	const struct tos_symbol_info *symbol;
42
43	printf(
44"TOS target options:\n"
45"  --set-tos value     Set Type of Service/Priority field to value\n"
46"  --set-tos symbol    Set TOS field (IPv4 only) by symbol\n"
47"                      Accepted symbolic names for value are:\n");
48
49	for (symbol = tos_symbol_names; symbol->name != NULL; ++symbol)
50		printf("                        (0x%02x) %2u %s\n",
51		       symbol->value, symbol->value, symbol->name);
52
53	printf("\n");
54}
55
56static void tos_tg_help(void)
57{
58	const struct tos_symbol_info *symbol;
59
60	printf(
61"TOS target v%s options:\n"
62"  --set-tos value[/mask]  Set Type of Service/Priority field to value\n"
63"                          (Zero out bits in mask and XOR value into TOS)\n"
64"  --set-tos symbol        Set TOS field (IPv4 only) by symbol\n"
65"                          (this zeroes the 4-bit Precedence part!)\n"
66"                          Accepted symbolic names for value are:\n",
67XTABLES_VERSION);
68
69	for (symbol = tos_symbol_names; symbol->name != NULL; ++symbol)
70		printf("                            (0x%02x) %2u %s\n",
71		       symbol->value, symbol->value, symbol->name);
72
73	printf(
74"\n"
75"  --and-tos bits          Binary AND the TOS value with bits\n"
76"  --or-tos  bits          Binary OR the TOS value with bits\n"
77"  --xor-tos bits          Binary XOR the TOS value with bits\n"
78);
79}
80
81static int tos_tg_parse_v0(int c, char **argv, int invert, unsigned int *flags,
82                           const void *entry, struct xt_entry_target **target)
83{
84	struct ipt_tos_target_info *info = (void *)(*target)->data;
85	struct tos_value_mask tvm;
86
87	switch (c) {
88	case '=':
89		xtables_param_act(XTF_ONLY_ONCE, "TOS", "--set-tos", *flags & FLAG_TOS);
90		xtables_param_act(XTF_NO_INVERT, "TOS", "--set-tos", invert);
91		if (!tos_parse_symbolic(optarg, &tvm, 0xFF))
92			xtables_param_act(XTF_BAD_VALUE, "TOS", "--set-tos", optarg);
93		if (tvm.mask != 0xFF)
94			xtables_error(PARAMETER_PROBLEM, "tos match: Your kernel "
95			           "is too old to support anything besides "
96				   "/0xFF as a mask.");
97		info->tos = tvm.value;
98		*flags |= FLAG_TOS;
99		return true;
100	}
101
102	return false;
103}
104
105static int tos_tg_parse(int c, char **argv, int invert, unsigned int *flags,
106                         const void *entry, struct xt_entry_target **target)
107{
108	struct xt_tos_target_info *info = (void *)(*target)->data;
109	struct tos_value_mask tvm;
110	unsigned int bits;
111
112	switch (c) {
113	case '=': /* --set-tos */
114		xtables_param_act(XTF_ONLY_ONCE, "TOS", "--set-tos", *flags & FLAG_TOS);
115		xtables_param_act(XTF_NO_INVERT, "TOS", "--set-tos", invert);
116		if (!tos_parse_symbolic(optarg, &tvm, 0x3F))
117			xtables_param_act(XTF_BAD_VALUE, "TOS", "--set-tos", optarg);
118		info->tos_value = tvm.value;
119		info->tos_mask  = tvm.mask;
120		break;
121
122	case '&': /* --and-tos */
123		xtables_param_act(XTF_ONLY_ONCE, "TOS", "--and-tos", *flags & FLAG_TOS);
124		xtables_param_act(XTF_NO_INVERT, "TOS", "--and-tos", invert);
125		if (!xtables_strtoui(optarg, NULL, &bits, 0, UINT8_MAX))
126			xtables_param_act(XTF_BAD_VALUE, "TOS", "--and-tos", optarg);
127		info->tos_value = 0;
128		info->tos_mask  = ~bits;
129		break;
130
131	case '|': /* --or-tos */
132		xtables_param_act(XTF_ONLY_ONCE, "TOS", "--or-tos", *flags & FLAG_TOS);
133		xtables_param_act(XTF_NO_INVERT, "TOS", "--or-tos", invert);
134		if (!xtables_strtoui(optarg, NULL, &bits, 0, UINT8_MAX))
135			xtables_param_act(XTF_BAD_VALUE, "TOS", "--or-tos", optarg);
136		info->tos_value = bits;
137		info->tos_mask  = bits;
138		break;
139
140	case '^': /* --xor-tos */
141		xtables_param_act(XTF_ONLY_ONCE, "TOS", "--xor-tos", *flags & FLAG_TOS);
142		xtables_param_act(XTF_NO_INVERT, "TOS", "--xor-tos", invert);
143		if (!xtables_strtoui(optarg, NULL, &bits, 0, UINT8_MAX))
144			xtables_param_act(XTF_BAD_VALUE, "TOS", "--xor-tos", optarg);
145		info->tos_value = bits;
146		info->tos_mask  = 0;
147		break;
148	}
149
150	*flags |= FLAG_TOS;
151	return true;
152}
153
154static void tos_tg_check(unsigned int flags)
155{
156	if (flags == 0)
157		xtables_error(PARAMETER_PROBLEM,
158		           "TOS: The --set-tos parameter is required");
159}
160
161static void tos_tg_print_v0(const void *ip,
162                            const struct xt_entry_target *target, int numeric)
163{
164	const struct ipt_tos_target_info *info = (const void *)target->data;
165
166	printf(" TOS set ");
167	if (numeric || !tos_try_print_symbolic("", info->tos, 0xFF))
168		printf("0x%02x", info->tos);
169}
170
171static void tos_tg_print(const void *ip, const struct xt_entry_target *target,
172                         int numeric)
173{
174	const struct xt_tos_target_info *info = (const void *)target->data;
175
176	if (numeric)
177		printf(" TOS set 0x%02x/0x%02x",
178		       info->tos_value, info->tos_mask);
179	else if (tos_try_print_symbolic(" TOS set",
180	    info->tos_value, info->tos_mask))
181		/* already printed by call */
182		return;
183	else if (info->tos_value == 0)
184		printf(" TOS and 0x%02x",
185		       (unsigned int)(uint8_t)~info->tos_mask);
186	else if (info->tos_value == info->tos_mask)
187		printf(" TOS or 0x%02x", info->tos_value);
188	else if (info->tos_mask == 0)
189		printf(" TOS xor 0x%02x", info->tos_value);
190	else
191		printf(" TOS set 0x%02x/0x%02x",
192		       info->tos_value, info->tos_mask);
193}
194
195static void tos_tg_save_v0(const void *ip, const struct xt_entry_target *target)
196{
197	const struct ipt_tos_target_info *info = (const void *)target->data;
198
199	printf(" --set-tos 0x%02x", info->tos);
200}
201
202static void tos_tg_save(const void *ip, const struct xt_entry_target *target)
203{
204	const struct xt_tos_target_info *info = (const void *)target->data;
205
206	printf(" --set-tos 0x%02x/0x%02x", info->tos_value, info->tos_mask);
207}
208
209static struct xtables_target tos_tg_reg[] = {
210	{
211		.version       = XTABLES_VERSION,
212		.name          = "TOS",
213		.revision      = 0,
214		.family        = NFPROTO_IPV4,
215		.size          = XT_ALIGN(sizeof(struct xt_tos_target_info)),
216		.userspacesize = XT_ALIGN(sizeof(struct xt_tos_target_info)),
217		.help          = tos_tg_help_v0,
218		.parse         = tos_tg_parse_v0,
219		.final_check   = tos_tg_check,
220		.print         = tos_tg_print_v0,
221		.save          = tos_tg_save_v0,
222		.extra_opts    = tos_tg_opts_v0,
223	},
224	{
225		.version       = XTABLES_VERSION,
226		.name          = "TOS",
227		.revision      = 1,
228		.family        = NFPROTO_UNSPEC,
229		.size          = XT_ALIGN(sizeof(struct xt_tos_target_info)),
230		.userspacesize = XT_ALIGN(sizeof(struct xt_tos_target_info)),
231		.help          = tos_tg_help,
232		.parse         = tos_tg_parse,
233		.final_check   = tos_tg_check,
234		.print         = tos_tg_print,
235		.save          = tos_tg_save,
236		.extra_opts    = tos_tg_opts,
237	},
238};
239
240void _init(void)
241{
242	xtables_register_targets(tos_tg_reg, ARRAY_SIZE(tos_tg_reg));
243}
244