libip6t_hbh.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
8#define DEBUG		0
9
10enum {
11	O_HBH_LEN = 0,
12	O_HBH_OPTS,
13};
14
15static void hbh_help(void)
16{
17	printf(
18"hbh match options:\n"
19"[!] --hbh-len length            total length of this header\n"
20"  --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
21"                                Options and its length (list, max: %d)\n",
22IP6T_OPTS_OPTSNR);
23}
24
25static const struct xt_option_entry hbh_opts[] = {
26	{.name = "hbh-len", .id = O_HBH_LEN, .type = XTTYPE_UINT32,
27	 .flags = XTOPT_INVERT | XTOPT_PUT,
28	 XTOPT_POINTER(struct ip6t_opts, hdrlen)},
29	{.name = "hbh-opts", .id = O_HBH_OPTS, .type = XTTYPE_STRING},
30	XTOPT_TABLEEND,
31};
32
33static uint32_t
34parse_opts_num(const char *idstr, const char *typestr)
35{
36	unsigned long int id;
37	char* ep;
38
39	id =  strtoul(idstr,&ep,0) ;
40
41	if ( idstr == ep ) {
42		xtables_error(PARAMETER_PROBLEM,
43			   "hbh: no valid digits in %s `%s'", typestr, idstr);
44	}
45	if ( id == ULONG_MAX  && errno == ERANGE ) {
46		xtables_error(PARAMETER_PROBLEM,
47			   "%s `%s' specified too big: would overflow",
48			   typestr, idstr);
49	}
50	if ( *idstr != '\0'  && *ep != '\0' ) {
51		xtables_error(PARAMETER_PROBLEM,
52			   "hbh: error parsing %s `%s'", typestr, idstr);
53	}
54	return id;
55}
56
57static int
58parse_options(const char *optsstr, uint16_t *opts)
59{
60        char *buffer, *cp, *next, *range;
61        unsigned int i;
62
63	buffer = strdup(optsstr);
64	if (!buffer) xtables_error(OTHER_PROBLEM, "strdup failed");
65
66        for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
67        {
68                next=strchr(cp, ',');
69                if (next) *next++='\0';
70                range = strchr(cp, ':');
71                if (range) {
72                        if (i == IP6T_OPTS_OPTSNR-1)
73				xtables_error(PARAMETER_PROBLEM,
74                                           "too many ports specified");
75                        *range++ = '\0';
76                }
77		opts[i] = (parse_opts_num(cp, "opt") & 0xFF) << 8;
78                if (range) {
79			if (opts[i] == 0)
80				xtables_error(PARAMETER_PROBLEM, "PAD0 has not got length");
81			opts[i] |= parse_opts_num(range, "length") & 0xFF;
82                } else {
83                        opts[i] |= (0x00FF);
84		}
85
86#if DEBUG
87		printf("opts str: %s %s\n", cp, range);
88		printf("opts opt: %04X\n", opts[i]);
89#endif
90	}
91	if (cp) xtables_error(PARAMETER_PROBLEM, "too many addresses specified");
92
93	free(buffer);
94
95#if DEBUG
96	printf("addr nr: %d\n", i);
97#endif
98
99	return i;
100}
101
102static void hbh_parse(struct xt_option_call *cb)
103{
104	struct ip6t_opts *optinfo = cb->data;
105
106	xtables_option_parse(cb);
107	switch (cb->entry->id) {
108	case O_HBH_LEN:
109		if (cb->invert)
110			optinfo->invflags |= IP6T_OPTS_INV_LEN;
111		break;
112	case O_HBH_OPTS:
113		optinfo->optsnr = parse_options(cb->arg, optinfo->opts);
114		optinfo->flags |= IP6T_OPTS_OPTS;
115		break;
116	}
117}
118
119static void
120print_options(unsigned int optsnr, uint16_t *optsp)
121{
122	unsigned int i;
123
124	for(i=0; i<optsnr; i++){
125		printf("%c", (i==0)?' ':',');
126		printf("%d", (optsp[i] & 0xFF00)>>8);
127		if ((optsp[i] & 0x00FF) != 0x00FF){
128			printf(":%d", (optsp[i] & 0x00FF));
129		}
130	}
131}
132
133static void hbh_print(const void *ip, const struct xt_entry_match *match,
134                      int numeric)
135{
136	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
137
138	printf(" hbh");
139	if (optinfo->flags & IP6T_OPTS_LEN) {
140		printf(" length");
141		printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
142		printf("%u", optinfo->hdrlen);
143	}
144	if (optinfo->flags & IP6T_OPTS_OPTS) printf(" opts");
145	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
146	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
147		printf(" Unknown invflags: 0x%X",
148		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);
149}
150
151static void hbh_save(const void *ip, const struct xt_entry_match *match)
152{
153	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
154
155	if (optinfo->flags & IP6T_OPTS_LEN) {
156		printf("%s --hbh-len %u",
157			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? " !" : "",
158			optinfo->hdrlen);
159	}
160
161	if (optinfo->flags & IP6T_OPTS_OPTS)
162		printf(" --hbh-opts");
163	print_options(optinfo->optsnr, (uint16_t *)optinfo->opts);
164}
165
166static struct xtables_match hbh_mt6_reg = {
167	.name 		= "hbh",
168	.version	= XTABLES_VERSION,
169	.family		= NFPROTO_IPV6,
170	.size		= XT_ALIGN(sizeof(struct ip6t_opts)),
171	.userspacesize	= XT_ALIGN(sizeof(struct ip6t_opts)),
172	.help		= hbh_help,
173	.print		= hbh_print,
174	.save		= hbh_save,
175	.x6_parse	= hbh_parse,
176	.x6_options	= hbh_opts,
177};
178
179void
180_init(void)
181{
182	xtables_register_match(&hbh_mt6_reg);
183}
184