libxt_esp.c revision bbe83862a5e1baf15f7c923352d4afdf59bc70e2 
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 <limits.h>
9
10#include <xtables.h>
11#include <linux/netfilter/xt_esp.h>
12
13static void esp_help(void)
14{
15	printf(
16"esp match options:\n"
17"[!] --espspi spi[:spi]\n"
18"				match spi (range)\n");
19}
20
21static const struct option esp_opts[] = {
22	{ "espspi", 1, NULL, '1' },
23	{ .name = NULL }
24};
25
26static u_int32_t
27parse_esp_spi(const char *spistr)
28{
29	unsigned long int spi;
30	char* ep;
31
32	spi =  strtoul(spistr,&ep,0) ;
33
34	if ( spistr == ep ) {
35		xtables_error(PARAMETER_PROBLEM,
36			   "ESP no valid digits in spi `%s'", spistr);
37	}
38	if ( spi == ULONG_MAX  && errno == ERANGE ) {
39		xtables_error(PARAMETER_PROBLEM,
40			   "spi `%s' specified too big: would overflow", spistr);
41	}
42	if ( *spistr != '\0'  && *ep != '\0' ) {
43		xtables_error(PARAMETER_PROBLEM,
44			   "ESP error parsing spi `%s'", spistr);
45	}
46	return spi;
47}
48
49static void
50parse_esp_spis(const char *spistring, u_int32_t *spis)
51{
52	char *buffer;
53	char *cp;
54
55	buffer = strdup(spistring);
56	if ((cp = strchr(buffer, ':')) == NULL)
57		spis[0] = spis[1] = parse_esp_spi(buffer);
58	else {
59		*cp = '\0';
60		cp++;
61
62		spis[0] = buffer[0] ? parse_esp_spi(buffer) : 0;
63		spis[1] = cp[0] ? parse_esp_spi(cp) : 0xFFFFFFFF;
64		if (spis[0] > spis[1])
65			xtables_error(PARAMETER_PROBLEM,
66				   "Invalid ESP spi range: %s", spistring);
67	}
68	free(buffer);
69}
70
71static void esp_init(struct xt_entry_match *m)
72{
73	struct xt_esp *espinfo = (struct xt_esp *)m->data;
74
75	espinfo->spis[1] = 0xFFFFFFFF;
76}
77
78#define ESP_SPI 0x01
79
80static int
81esp_parse(int c, char **argv, int invert, unsigned int *flags,
82          const void *entry, struct xt_entry_match **match)
83{
84	struct xt_esp *espinfo = (struct xt_esp *)(*match)->data;
85
86	switch (c) {
87	case '1':
88		if (*flags & ESP_SPI)
89			xtables_error(PARAMETER_PROBLEM,
90				   "Only one `--espspi' allowed");
91		xtables_check_inverse(optarg, &invert, &optind, 0, argv);
92		parse_esp_spis(optarg, espinfo->spis);
93		if (invert)
94			espinfo->invflags |= XT_ESP_INV_SPI;
95		*flags |= ESP_SPI;
96		break;
97	default:
98		return 0;
99	}
100
101	return 1;
102}
103
104static void
105print_spis(const char *name, u_int32_t min, u_int32_t max,
106	    int invert)
107{
108	const char *inv = invert ? "!" : "";
109
110	if (min != 0 || max != 0xFFFFFFFF || invert) {
111		if (min == max)
112			printf("%s:%s%u ", name, inv, min);
113		else
114			printf("%ss:%s%u:%u ", name, inv, min, max);
115	}
116}
117
118static void
119esp_print(const void *ip, const struct xt_entry_match *match, int numeric)
120{
121	const struct xt_esp *esp = (struct xt_esp *)match->data;
122
123	printf("esp ");
124	print_spis("spi", esp->spis[0], esp->spis[1],
125		    esp->invflags & XT_ESP_INV_SPI);
126	if (esp->invflags & ~XT_ESP_INV_MASK)
127		printf("Unknown invflags: 0x%X ",
128		       esp->invflags & ~XT_ESP_INV_MASK);
129}
130
131static void esp_save(const void *ip, const struct xt_entry_match *match)
132{
133	const struct xt_esp *espinfo = (struct xt_esp *)match->data;
134
135	if (!(espinfo->spis[0] == 0
136	    && espinfo->spis[1] == 0xFFFFFFFF)) {
137		printf("%s--espspi ",
138			(espinfo->invflags & XT_ESP_INV_SPI) ? "! " : "");
139		if (espinfo->spis[0]
140		    != espinfo->spis[1])
141			printf("%u:%u ",
142			       espinfo->spis[0],
143			       espinfo->spis[1]);
144		else
145			printf("%u ",
146			       espinfo->spis[0]);
147	}
148
149}
150
151static struct xtables_match esp_match = {
152	.family		= NFPROTO_UNSPEC,
153	.name 		= "esp",
154	.version 	= XTABLES_VERSION,
155	.size		= XT_ALIGN(sizeof(struct xt_esp)),
156	.userspacesize	= XT_ALIGN(sizeof(struct xt_esp)),
157	.help		= esp_help,
158	.init		= esp_init,
159	.parse		= esp_parse,
160	.print		= esp_print,
161	.save		= esp_save,
162	.extra_opts	= esp_opts,
163};
164
165void
166_init(void)
167{
168	xtables_register_match(&esp_match);
169}
170