summaryrefslogtreecommitdiffstats
path: root/extensions/libip6t_ah.c
blob: 087b3ac320a5900795b50937c513c229a013ee51 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
#include <stdio.h>
#include <xtables.h>
#include <linux/netfilter_ipv6/ip6t_ah.h>

enum {
	O_AHSPI = 0,
	O_AHLEN,
	O_AHRES,
};

static void ah_help(void)
{
	printf(
"ah match options:\n"
"[!] --ahspi spi[:spi]          match spi (range)\n"
"[!] --ahlen length             total length of this header\n"
" --ahres                       check the reserved field too\n");
}

#define s struct ip6t_ah
static const struct xt_option_entry ah_opts[] = {
	{.name = "ahspi", .id = O_AHSPI, .type = XTTYPE_UINT32RC,
	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spis)},
	{.name = "ahlen", .id = O_AHLEN, .type = XTTYPE_UINT32,
	 .flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, hdrlen)},
	{.name = "ahres", .id = O_AHRES, .type = XTTYPE_NONE},
	XTOPT_TABLEEND,
};
#undef s

static void ah_init(struct xt_entry_match *m)
{
	struct ip6t_ah *ahinfo = (void *)m->data;

	/* Defaults for when no --ahspi is used at all */
	ahinfo->spis[1] = ~0U;
}

static void ah_parse(struct xt_option_call *cb)
{
	struct ip6t_ah *ahinfo = cb->data;

	xtables_option_parse(cb);
	switch (cb->entry->id) {
	case O_AHSPI:
		if (cb->nvals == 1)
			ahinfo->spis[1] = ahinfo->spis[0];
		if (cb->invert)
			ahinfo->invflags |= IP6T_AH_INV_SPI;
		break;
	case O_AHLEN:
		if (cb->invert)
			ahinfo->invflags |= IP6T_AH_INV_LEN;
		break;
	case O_AHRES:
		ahinfo->hdrres = 1;
		break;
	}
}

static void
print_spis(const char *name, uint32_t min, uint32_t max,
	    int invert)
{
	const char *inv = invert ? "!" : "";

	if (min != 0 || max != 0xFFFFFFFF || invert) {
		if (min == max)
			printf("%s:%s%u", name, inv, min);
		else
			printf("%ss:%s%u:%u", name, inv, min, max);
	}
}

static void
print_len(const char *name, uint32_t len, int invert)
{
	const char *inv = invert ? "!" : "";

	if (len != 0 || invert)
		printf("%s:%s%u", name, inv, len);
}

static void ah_print(const void *ip, const struct xt_entry_match *match,
                     int numeric)
{
	const struct ip6t_ah *ah = (struct ip6t_ah *)match->data;

	printf(" ah ");
	print_spis("spi", ah->spis[0], ah->spis[1],
		    ah->invflags & IP6T_AH_INV_SPI);
	print_len("length", ah->hdrlen, 
		    ah->invflags & IP6T_AH_INV_LEN);

	if (ah->hdrres)
		printf(" reserved");

	if (ah->invflags & ~IP6T_AH_INV_MASK)
		printf(" Unknown invflags: 0x%X",
		       ah->invflags & ~IP6T_AH_INV_MASK);
}

static void ah_save(const void *ip, const struct xt_entry_match *match)
{
	const struct ip6t_ah *ahinfo = (struct ip6t_ah *)match->data;

	if (!(ahinfo->spis[0] == 0
	    && ahinfo->spis[1] == 0xFFFFFFFF)) {
		printf("%s --ahspi ",
			(ahinfo->invflags & IP6T_AH_INV_SPI) ? " !" : "");
		if (ahinfo->spis[0]
		    != ahinfo->spis[1])
			printf("%u:%u",
			       ahinfo->spis[0],
			       ahinfo->spis[1]);
		else
			printf("%u",
			       ahinfo->spis[0]);
	}

	if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN) ) {
		printf("%s --ahlen %u",
			(ahinfo->invflags & IP6T_AH_INV_LEN) ? " !" : "",
			ahinfo->hdrlen);
	}

	if (ahinfo->hdrres != 0 )
		printf(" --ahres");
}

static int ah_xlate(const struct xt_entry_match *match,
		    struct xt_xlate *xl, int numeric)
{
	const struct ip6t_ah *ahinfo = (struct ip6t_ah *)match->data;

	if (!(ahinfo->spis[0] == 0 && ahinfo->spis[1] == 0xFFFFFFFF)) {
		xt_xlate_add(xl, "ah spi%s ",
			   (ahinfo->invflags & IP6T_AH_INV_SPI) ? " !=" : "");
	if (ahinfo->spis[0] != ahinfo->spis[1])
		xt_xlate_add(xl, "%u-%u ", ahinfo->spis[0], ahinfo->spis[1]);
	else
		xt_xlate_add(xl, "%u ", ahinfo->spis[0]);
	}

	if (ahinfo->hdrlen != 0 || (ahinfo->invflags & IP6T_AH_INV_LEN)) {
		xt_xlate_add(xl, "ah hdrlength%s %u ",
			   (ahinfo->invflags & IP6T_AH_INV_LEN) ? " !=" : "",
			   ahinfo->hdrlen);
	}

	if (ahinfo->hdrres != 0)
		xt_xlate_add(xl, "ah reserved %u ", ahinfo->hdrres);

	return 1;
}

static struct xtables_match ah_mt6_reg = {
	.name          = "ah",
	.version       = XTABLES_VERSION,
	.family        = NFPROTO_IPV6,
	.size          = XT_ALIGN(sizeof(struct ip6t_ah)),
	.userspacesize = XT_ALIGN(sizeof(struct ip6t_ah)),
	.help          = ah_help,
	.init          = ah_init,
	.print         = ah_print,
	.save          = ah_save,
	.x6_parse      = ah_parse,
	.x6_options    = ah_opts,
	.xlate	       = ah_xlate,
};

void
_init(void)
{
	xtables_register_match(&ah_mt6_reg);
}