1/* Shared library add-on to ip6tables 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 <ip6tables.h>
9#include <linux/netfilter_ipv6/ip6t_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]        match spi (range)\n",
18IPTABLES_VERSION);
19}
20
21static struct option opts[] = {
22	{ .name = "espspi", .has_arg = 1, .flag = 0, .val = '1' },
23	{ .name = 0 }
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		exit_error(PARAMETER_PROBLEM,
36			   "ESP no valid digits in spi `%s'", spistr);
37	}
38	if ( spi == ULONG_MAX  && errno == ERANGE ) {
39		exit_error(PARAMETER_PROBLEM,
40			   "spi `%s' specified too big: would overflow", spistr);
41	}
42	if ( *spistr != '\0'  && *ep != '\0' ) {
43		exit_error(PARAMETER_PROBLEM,
44			   "ESP error parsing spi `%s'", spistr);
45	}
46	return (u_int32_t) 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			exit_error(PARAMETER_PROBLEM,
66				   "Invalid ESP spi range: %s", spistring);
67	}
68	free(buffer);
69}
70
71/* Initialize the match. */
72static void
73init(struct ip6t_entry_match *m, unsigned int *nfcache)
74{
75	struct ip6t_esp *espinfo = (struct ip6t_esp *)m->data;
76
77	espinfo->spis[1] = 0xFFFFFFFF;
78}
79
80#define ESP_SPI 0x01
81
82/* Function which parses command options; returns true if it
83   ate an option */
84static int
85parse(int c, char **argv, int invert, unsigned int *flags,
86      const struct ip6t_entry *entry,
87      unsigned int *nfcache,
88      struct ip6t_entry_match **match)
89{
90	struct ip6t_esp *espinfo = (struct ip6t_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 |= IP6T_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 ip6t_matchinfo. */
131static void
132print(const struct ip6t_ip6 *ip,
133      const struct ip6t_entry_match *match, int numeric)
134{
135	const struct ip6t_esp *esp = (struct ip6t_esp *)match->data;
136
137	printf("esp ");
138	print_spis("spi", esp->spis[0], esp->spis[1],
139		    esp->invflags & IP6T_ESP_INV_SPI);
140	if (esp->invflags & ~IP6T_ESP_INV_MASK)
141		printf("Unknown invflags: 0x%X ",
142		       esp->invflags & ~IP6T_ESP_INV_MASK);
143}
144
145/* Saves the union ip6t_matchinfo in parsable form to stdout. */
146static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match)
147{
148	const struct ip6t_esp *espinfo = (struct ip6t_esp *)match->data;
149
150	if (!(espinfo->spis[0] == 0
151	    && espinfo->spis[1] == 0xFFFFFFFF)) {
152		printf("--espspi %s",
153			(espinfo->invflags & IP6T_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
167struct ip6tables_match esp = {
168	.name          = "esp",
169	.version       = IPTABLES_VERSION,
170	.size          = IP6T_ALIGN(sizeof(struct ip6t_esp)),
171	.userspacesize = IP6T_ALIGN(sizeof(struct ip6t_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
181void
182_init(void)
183{
184	register_match6(&esp);
185}
186