libip6t_hbh.c revision cea9f71f5618250a38acb21c31fbbf93a752f7d4 
1/* Shared library add-on to ip6tables to add Hop-by-Hop header 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 <xtables.h>
9/*#include <linux/in6.h>*/
10#include <linux/netfilter_ipv6/ip6t_opts.h>
11#include <sys/types.h>
12#include <sys/socket.h>
13#include <arpa/inet.h>
14
15#define DEBUG		0
16
17static void hbh_help(void)
18{
19	printf(
20"hbh match options:\n"
21"[!] --hbh-len length            total length of this header\n"
22"  --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
23"                                Options and its length (list, max: %d)\n",
24IP6T_OPTS_OPTSNR);
25}
26
27static const struct option hbh_opts[] = {
28	{ "hbh-len", 1, NULL, '1' },
29	{ "hbh-opts", 1, NULL, '2' },
30	{ "hbh-not-strict", 1, NULL, '3' },
31	{ .name = NULL }
32};
33
34static u_int32_t
35parse_opts_num(const char *idstr, const char *typestr)
36{
37	unsigned long int id;
38	char* ep;
39
40	id =  strtoul(idstr,&ep,0) ;
41
42	if ( idstr == ep ) {
43		exit_error(PARAMETER_PROBLEM,
44			   "hbh: no valid digits in %s `%s'", typestr, idstr);
45	}
46	if ( id == ULONG_MAX  && errno == ERANGE ) {
47		exit_error(PARAMETER_PROBLEM,
48			   "%s `%s' specified too big: would overflow",
49			   typestr, idstr);
50	}
51	if ( *idstr != '\0'  && *ep != '\0' ) {
52		exit_error(PARAMETER_PROBLEM,
53			   "hbh: error parsing %s `%s'", typestr, idstr);
54	}
55	return (u_int32_t) id;
56}
57
58static int
59parse_options(const char *optsstr, u_int16_t *opts)
60{
61        char *buffer, *cp, *next, *range;
62        unsigned int i;
63
64	buffer = strdup(optsstr);
65        if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
66
67        for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
68        {
69                next=strchr(cp, ',');
70                if (next) *next++='\0';
71                range = strchr(cp, ':');
72                if (range) {
73                        if (i == IP6T_OPTS_OPTSNR-1)
74                                exit_error(PARAMETER_PROBLEM,
75                                           "too many ports specified");
76                        *range++ = '\0';
77                }
78                opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8);
79                if (range) {
80			if (opts[i] == 0)
81        			exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
82                        opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
83					0x000000FF);
84                } else {
85                        opts[i] |= (0x00FF);
86		}
87
88#if DEBUG
89		printf("opts str: %s %s\n", cp, range);
90		printf("opts opt: %04X\n", opts[i]);
91#endif
92	}
93        if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
94
95	free(buffer);
96
97#if DEBUG
98	printf("addr nr: %d\n", i);
99#endif
100
101	return i;
102}
103
104static void hbh_init(struct xt_entry_match *m)
105{
106	struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
107
108	optinfo->hdrlen = 0;
109	optinfo->flags = 0;
110	optinfo->invflags = 0;
111	optinfo->optsnr = 0;
112}
113
114static int hbh_parse(int c, char **argv, int invert, unsigned int *flags,
115                     const void *entry, struct xt_entry_match **match)
116{
117	struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
118
119	switch (c) {
120	case '1':
121		if (*flags & IP6T_OPTS_LEN)
122			exit_error(PARAMETER_PROBLEM,
123				   "Only one `--hbh-len' allowed");
124		check_inverse(optarg, &invert, &optind, 0);
125		optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
126		if (invert)
127			optinfo->invflags |= IP6T_OPTS_INV_LEN;
128		optinfo->flags |= IP6T_OPTS_LEN;
129		*flags |= IP6T_OPTS_LEN;
130		break;
131	case '2':
132		if (*flags & IP6T_OPTS_OPTS)
133			exit_error(PARAMETER_PROBLEM,
134				   "Only one `--hbh-opts' allowed");
135                check_inverse(optarg, &invert, &optind, 0);
136                if (invert)
137                        exit_error(PARAMETER_PROBLEM,
138				" '!' not allowed with `--hbh-opts'");
139		optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
140		optinfo->flags |= IP6T_OPTS_OPTS;
141		*flags |= IP6T_OPTS_OPTS;
142		break;
143	case '3':
144		if (*flags & IP6T_OPTS_NSTRICT)
145			exit_error(PARAMETER_PROBLEM,
146				   "Only one `--hbh-not-strict' allowed");
147		if ( !(*flags & IP6T_OPTS_OPTS) )
148			exit_error(PARAMETER_PROBLEM,
149				   "`--hbh-opts ...' required before `--hbh-not-strict'");
150		optinfo->flags |= IP6T_OPTS_NSTRICT;
151		*flags |= IP6T_OPTS_NSTRICT;
152		break;
153	default:
154		return 0;
155	}
156
157	return 1;
158}
159
160static void
161print_options(unsigned int optsnr, u_int16_t *optsp)
162{
163	unsigned int i;
164
165	for(i=0; i<optsnr; i++){
166		printf("%d", (optsp[i] & 0xFF00)>>8);
167		if ((optsp[i] & 0x00FF) != 0x00FF){
168			printf(":%d", (optsp[i] & 0x00FF));
169		}
170		printf("%c", (i!=optsnr-1)?',':' ');
171	}
172}
173
174static void hbh_print(const void *ip, const struct xt_entry_match *match,
175                      int numeric)
176{
177	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
178
179	printf("hbh ");
180	if (optinfo->flags & IP6T_OPTS_LEN) {
181		printf("length");
182		printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
183		printf("%u", optinfo->hdrlen);
184		printf(" ");
185	}
186	if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
187	print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
188	if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
189	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
190		printf("Unknown invflags: 0x%X ",
191		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);
192}
193
194static void hbh_save(const void *ip, const struct xt_entry_match *match)
195{
196	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
197
198	if (optinfo->flags & IP6T_OPTS_LEN) {
199		printf("%s--hbh-len %u ",
200			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
201			optinfo->hdrlen);
202	}
203
204	if (optinfo->flags & IP6T_OPTS_OPTS)
205		printf("--hbh-opts ");
206	print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
207	if (optinfo->flags & IP6T_OPTS_NSTRICT)
208		printf("--hbh-not-strict ");
209}
210
211static struct xtables_match hbh_mt6_reg = {
212	.name 		= "hbh",
213	.version	= XTABLES_VERSION,
214	.family		= NFPROTO_IPV6,
215	.size		= XT_ALIGN(sizeof(struct ip6t_opts)),
216	.userspacesize	= XT_ALIGN(sizeof(struct ip6t_opts)),
217	.help		= hbh_help,
218	.init		= hbh_init,
219	.parse		= hbh_parse,
220	.print		= hbh_print,
221	.save		= hbh_save,
222	.extra_opts	= hbh_opts,
223};
224
225void
226_init(void)
227{
228	xtables_register_match(&hbh_mt6_reg);
229}
230