libip6t_dst.c revision e37d45ce390c2f5a7f1e64742b9100ecef0def54 
1#include <stdio.h>
2#include <string.h>
3#include <stdlib.h>
4#include <errno.h>
5#include <xtables.h>
6#include <linux/netfilter_ipv6/ip6t_opts.h>
7
8enum {
9	O_DSTLEN = 0,
10	O_DSTOPTS,
11};
12
13static void dst_help(void)
14{
15	printf(
16"dst match options:\n"
17"[!] --dst-len length            total length of this header\n"
18"  --dst-opts TYPE[:LEN][,TYPE[:LEN]...]\n"
19"                                Options and its length (list, max: %d)\n",
20IP6T_OPTS_OPTSNR);
21}
22
23static const struct xt_option_entry dst_opts[] = {
24	{.name = "dst-len", .id = O_DSTLEN, .type = XTTYPE_UINT32,
25	 .flags = XTOPT_INVERT | XTOPT_PUT,
26	 XTOPT_POINTER(struct ip6t_opts, hdrlen)},
27	{.name = "dst-opts", .id = O_DSTOPTS, .type = XTTYPE_STRING},
28	XTOPT_TABLEEND,
29};
30
31static uint32_t
32parse_opts_num(const char *idstr, const char *typestr)
33{
34	unsigned long int id;
35	char* ep;
36
37	id = strtoul(idstr, &ep, 0);
38
39	if ( idstr == ep ) {
40		xtables_error(PARAMETER_PROBLEM,
41		           "dst: no valid digits in %s `%s'", typestr, idstr);
42	}
43	if ( id == ULONG_MAX  && errno == ERANGE ) {
44		xtables_error(PARAMETER_PROBLEM,
45			   "%s `%s' specified too big: would overflow",
46			   typestr, idstr);
47	}
48	if ( *idstr != '\0'  && *ep != '\0' ) {
49		xtables_error(PARAMETER_PROBLEM,
50		           "dst: error parsing %s `%s'", typestr, idstr);
51	}
52	return id;
53}
54
55static int
56parse_options(const char *optsstr, uint16_t *opts)
57{
58        char *buffer, *cp, *next, *range;
59        unsigned int i;
60
61	buffer = strdup(optsstr);
62        if (!buffer)
63		xtables_error(OTHER_PROBLEM, "strdup failed");
64
65        for (cp = buffer, i = 0; cp && i < IP6T_OPTS_OPTSNR; cp = next, i++)
66        {
67                next = strchr(cp, ',');
68
69                if (next)
70			*next++='\0';
71
72                range = strchr(cp, ':');
73
74                if (range) {
75                        if (i == IP6T_OPTS_OPTSNR-1)
76				xtables_error(PARAMETER_PROBLEM,
77                                           "too many ports specified");
78                        *range++ = '\0';
79                }
80
81		opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
82                if (range) {
83			if (opts[i] == 0)
84				xtables_error(PARAMETER_PROBLEM,
85					"PAD0 hasn't got length");
86			opts[i] |= parse_opts_num(range, "length") & 0xFF;
87                } else
88                        opts[i] |= (0x00FF);
89
90#ifdef DEBUG
91		printf("opts str: %s %s\n", cp, range);
92		printf("opts opt: %04X\n", opts[i]);
93#endif
94	}
95
96        if (cp)
97		xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
98
99	free(buffer);
100
101#ifdef DEBUG
102	printf("addr nr: %d\n", i);
103#endif
104
105	return i;
106}
107
108static void dst_parse(struct xt_option_call *cb)
109{
110	struct ip6t_opts *optinfo = cb->data;
111
112	xtables_option_parse(cb);
113	switch (cb->entry->id) {
114	case O_DSTOPTS:
115		optinfo->optsnr = parse_options(cb->arg, optinfo->opts);
116		optinfo->flags |= IP6T_OPTS_OPTS;
117		break;
118	}
119}
120
121static void
122print_options(unsigned int optsnr, uint16_t *optsp)
123{
124	unsigned int i;
125
126	printf(" ");
127	for(i = 0; i < optsnr; i++) {
128		printf("%d", (optsp[i] & 0xFF00) >> 8);
129
130		if ((optsp[i] & 0x00FF) != 0x00FF)
131			printf(":%d", (optsp[i] & 0x00FF));
132
133		printf("%c", (i != optsnr - 1) ? ',' : ' ');
134	}
135}
136
137static void dst_print(const void *ip, const struct xt_entry_match *match,
138                      int numeric)
139{
140	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
141
142	printf(" dst");
143	if (optinfo->flags & IP6T_OPTS_LEN)
144		printf(" length:%s%u",
145			optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "",
146			optinfo->hdrlen);
147
148	if (optinfo->flags & IP6T_OPTS_OPTS)
149		printf(" opts");
150
151	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
152
153	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
154		printf(" Unknown invflags: 0x%X",
155		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);
156}
157
158static void dst_save(const void *ip, const struct xt_entry_match *match)
159{
160	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
161
162	if (optinfo->flags & IP6T_OPTS_LEN) {
163		printf("%s --dst-len %u",
164			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",
165			optinfo->hdrlen);
166	}
167
168	if (optinfo->flags & IP6T_OPTS_OPTS)
169		printf(" --dst-opts");
170
171	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
172}
173
174static struct xtables_match dst_mt6_reg = {
175	.name          = "dst",
176	.version       = XTABLES_VERSION,
177	.family        = NFPROTO_IPV6,
178	.size          = XT_ALIGN(sizeof(struct ip6t_opts)),
179	.userspacesize = XT_ALIGN(sizeof(struct ip6t_opts)),
180	.help          = dst_help,
181	.print         = dst_print,
182	.save          = dst_save,
183	.x6_parse      = dst_parse,
184	.x6_options    = dst_opts,
185};
186
187void
188_init(void)
189{
190	xtables_register_match(&dst_mt6_reg);
191}
192