libxt_esp.c revision ea146a982e26c42f9954f140276f8deeb2edbe98 
1/* Shared library add-on to iptables to add ESP support. */
2#include <stdio.h>
3#include <netdb.h>
4#include <string.h>
5#include <stdlib.h>
6#include <getopt.h>
7#include <errno.h>
8#include <xtables.h>
9#include <linux/netfilter/xt_esp.h>
10
11/* Function which prints out usage message. */
12static void
13help(void)
14{
15	printf(
16"ESP v%s options:\n"
17" --espspi [!] spi[:spi]\n"
18"				match spi (range)\n",
19IPTABLES_VERSION);
20}
21
22static const struct option opts[] = {
23	{ "espspi", 1, 0, '1' },
24	{0}
25};
26
27static u_int32_t
28parse_esp_spi(const char *spistr)
29{
30	unsigned long int spi;
31	char* ep;
32
33	spi =  strtoul(spistr,&ep,0) ;
34
35	if ( spistr == ep ) {
36		exit_error(PARAMETER_PROBLEM,
37			   "ESP no valid digits in spi `%s'", spistr);
38	}
39	if ( spi == ULONG_MAX  && errno == ERANGE ) {
40		exit_error(PARAMETER_PROBLEM,
41			   "spi `%s' specified too big: would overflow", spistr);
42	}
43	if ( *spistr != '\0'  && *ep != '\0' ) {
44		exit_error(PARAMETER_PROBLEM,
45			   "ESP error parsing spi `%s'", spistr);
46	}
47	return (u_int32_t) spi;
48}
49
50static void
51parse_esp_spis(const char *spistring, u_int32_t *spis)
52{
53	char *buffer;
54	char *cp;
55
56	buffer = strdup(spistring);
57	if ((cp = strchr(buffer, ':')) == NULL)
58		spis[0] = spis[1] = parse_esp_spi(buffer);
59	else {
60		*cp = '\0';
61		cp++;
62
63		spis[0] = buffer[0] ? parse_esp_spi(buffer) : 0;
64		spis[1] = cp[0] ? parse_esp_spi(cp) : 0xFFFFFFFF;
65		if (spis[0] > spis[1])
66			exit_error(PARAMETER_PROBLEM,
67				   "Invalid ESP spi range: %s", spistring);
68	}
69	free(buffer);
70}
71
72/* Initialize the match. */
73static void
74init(struct xt_entry_match *m)
75{
76	struct xt_esp *espinfo = (struct xt_esp *)m->data;
77
78	espinfo->spis[1] = 0xFFFFFFFF;
79}
80
81#define ESP_SPI 0x01
82
83/* Function which parses command options; returns true if it
84   ate an option */
85static int
86parse(int c, char **argv, int invert, unsigned int *flags,
87      const void *entry,
88      struct xt_entry_match **match)
89{
90	struct xt_esp *espinfo = (struct xt_esp *)(*match)->data;
91
92	switch (c) {
93	case '1':
94		if (*flags & ESP_SPI)
95			exit_error(PARAMETER_PROBLEM,
96				   "Only one `--espspi' allowed");
97		check_inverse(optarg, &invert, &optind, 0);
98		parse_esp_spis(argv[optind-1], espinfo->spis);
99		if (invert)
100			espinfo->invflags |= XT_ESP_INV_SPI;
101		*flags |= ESP_SPI;
102		break;
103	default:
104		return 0;
105	}
106
107	return 1;
108}
109
110/* Final check; we don't care. */
111static void
112final_check(unsigned int flags)
113{
114}
115
116static void
117print_spis(const char *name, u_int32_t min, u_int32_t max,
118	    int invert)
119{
120	const char *inv = invert ? "!" : "";
121
122	if (min != 0 || max != 0xFFFFFFFF || invert) {
123		if (min == max)
124			printf("%s:%s%u ", name, inv, min);
125		else
126			printf("%ss:%s%u:%u ", name, inv, min, max);
127	}
128}
129
130/* Prints out the union ipt_matchinfo. */
131static void
132print(const void *ip,
133      const struct xt_entry_match *match, int numeric)
134{
135	const struct xt_esp *esp = (struct xt_esp *)match->data;
136
137	printf("esp ");
138	print_spis("spi", esp->spis[0], esp->spis[1],
139		    esp->invflags & XT_ESP_INV_SPI);
140	if (esp->invflags & ~XT_ESP_INV_MASK)
141		printf("Unknown invflags: 0x%X ",
142		       esp->invflags & ~XT_ESP_INV_MASK);
143}
144
145/* Saves the union ipt_matchinfo in parsable form to stdout. */
146static void save(const void *ip, const struct xt_entry_match *match)
147{
148	const struct xt_esp *espinfo = (struct xt_esp *)match->data;
149
150	if (!(espinfo->spis[0] == 0
151	    && espinfo->spis[1] == 0xFFFFFFFF)) {
152		printf("--espspi %s",
153			(espinfo->invflags & XT_ESP_INV_SPI) ? "! " : "");
154		if (espinfo->spis[0]
155		    != espinfo->spis[1])
156			printf("%u:%u ",
157			       espinfo->spis[0],
158			       espinfo->spis[1]);
159		else
160			printf("%u ",
161			       espinfo->spis[0]);
162	}
163
164}
165
166static struct xtables_match esp = {
167	.family		= AF_INET,
168	.name 		= "esp",
169	.version 	= IPTABLES_VERSION,
170	.size		= XT_ALIGN(sizeof(struct xt_esp)),
171	.userspacesize	= XT_ALIGN(sizeof(struct xt_esp)),
172	.help		= &help,
173	.init		= &init,
174	.parse		= &parse,
175	.final_check	= &final_check,
176	.print		= &print,
177	.save		= &save,
178	.extra_opts	= opts
179};
180
181static struct xtables_match esp6 = {
182	.family		= AF_INET6,
183	.name 		= "esp",
184	.version 	= IPTABLES_VERSION,
185	.size		= XT_ALIGN(sizeof(struct xt_esp)),
186	.userspacesize	= XT_ALIGN(sizeof(struct xt_esp)),
187	.help		= &help,
188	.init		= &init,
189	.parse		= &parse,
190	.final_check	= &final_check,
191	.print		= &print,
192	.save		= &save,
193	.extra_opts	= opts
194};
195
196void
197_init(void)
198{
199	xtables_register_match(&esp);
200	xtables_register_match(&esp6);
201}
202