libip6t_hbh.c revision 7a236f4cc685a420c1a782a5db614a93baf37ccf 
1/* Shared library add-on to ip6tables to add Hop-by-Hop and Dst headers 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/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
17/* Function which prints out usage message. */
18static void hbh_help(void)
19{
20	printf(
21"hbh v%s options:\n"
22"  --hbh-len [!] length          total length of this header\n"
23"  --hbh-opts TYPE[:LEN][,TYPE[:LEN]...] \n"
24"                                Options and its length (list, max: %d)\n",
25IPTABLES_VERSION, IP6T_OPTS_OPTSNR);
26}
27
28static const struct option hbh_opts[] = {
29	{ "hbh-len", 1, NULL, '1' },
30	{ "hbh-opts", 1, NULL, '2' },
31	{ "hbh-not-strict", 1, NULL, '3' },
32	{ .name = NULL }
33};
34
35static u_int32_t
36parse_opts_num(const char *idstr, const char *typestr)
37{
38	unsigned long int id;
39	char* ep;
40
41	id =  strtoul(idstr,&ep,0) ;
42
43	if ( idstr == ep ) {
44		exit_error(PARAMETER_PROBLEM,
45			   "hbh: no valid digits in %s `%s'", typestr, idstr);
46	}
47	if ( id == ULONG_MAX  && errno == ERANGE ) {
48		exit_error(PARAMETER_PROBLEM,
49			   "%s `%s' specified too big: would overflow",
50			   typestr, idstr);
51	}
52	if ( *idstr != '\0'  && *ep != '\0' ) {
53		exit_error(PARAMETER_PROBLEM,
54			   "hbh: error parsing %s `%s'", typestr, idstr);
55	}
56	return (u_int32_t) id;
57}
58
59static int
60parse_options(const char *optsstr, u_int16_t *opts)
61{
62        char *buffer, *cp, *next, *range;
63        unsigned int i;
64
65	buffer = strdup(optsstr);
66        if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");
67
68        for (cp=buffer, i=0; cp && i<IP6T_OPTS_OPTSNR; cp=next,i++)
69        {
70                next=strchr(cp, ',');
71                if (next) *next++='\0';
72                range = strchr(cp, ':');
73                if (range) {
74                        if (i == IP6T_OPTS_OPTSNR-1)
75                                exit_error(PARAMETER_PROBLEM,
76                                           "too many ports specified");
77                        *range++ = '\0';
78                }
79                opts[i] = (u_int16_t)((parse_opts_num(cp,"opt") & 0x000000FF)<<8);
80                if (range) {
81			if (opts[i] == 0)
82        			exit_error(PARAMETER_PROBLEM, "PAD0 hasn't got length");
83                        opts[i] |= (u_int16_t)(parse_opts_num(range,"length") &
84					0x000000FF);
85                } else {
86                        opts[i] |= (0x00FF);
87		}
88
89#if DEBUG
90		printf("opts str: %s %s\n", cp, range);
91		printf("opts opt: %04X\n", opts[i]);
92#endif
93	}
94        if (cp) exit_error(PARAMETER_PROBLEM, "too many addresses specified");
95
96	free(buffer);
97
98#if DEBUG
99	printf("addr nr: %d\n", i);
100#endif
101
102	return i;
103}
104
105/* Initialize the match. */
106static void hbh_init(struct xt_entry_match *m)
107{
108	struct ip6t_opts *optinfo = (struct ip6t_opts *)m->data;
109
110	optinfo->hdrlen = 0;
111	optinfo->flags = 0;
112	optinfo->invflags = 0;
113	optinfo->optsnr = 0;
114}
115
116/* Function which parses command options; returns true if it
117   ate an option */
118static int hbh_parse(int c, char **argv, int invert, unsigned int *flags,
119                     const void *entry, struct xt_entry_match **match)
120{
121	struct ip6t_opts *optinfo = (struct ip6t_opts *)(*match)->data;
122
123	switch (c) {
124	case '1':
125		if (*flags & IP6T_OPTS_LEN)
126			exit_error(PARAMETER_PROBLEM,
127				   "Only one `--hbh-len' allowed");
128		check_inverse(optarg, &invert, &optind, 0);
129		optinfo->hdrlen = parse_opts_num(argv[optind-1], "length");
130		if (invert)
131			optinfo->invflags |= IP6T_OPTS_INV_LEN;
132		optinfo->flags |= IP6T_OPTS_LEN;
133		*flags |= IP6T_OPTS_LEN;
134		break;
135	case '2':
136		if (*flags & IP6T_OPTS_OPTS)
137			exit_error(PARAMETER_PROBLEM,
138				   "Only one `--hbh-opts' allowed");
139                check_inverse(optarg, &invert, &optind, 0);
140                if (invert)
141                        exit_error(PARAMETER_PROBLEM,
142				" '!' not allowed with `--hbh-opts'");
143		optinfo->optsnr = parse_options(argv[optind-1], optinfo->opts);
144		optinfo->flags |= IP6T_OPTS_OPTS;
145		*flags |= IP6T_OPTS_OPTS;
146		break;
147	case '3':
148		if (*flags & IP6T_OPTS_NSTRICT)
149			exit_error(PARAMETER_PROBLEM,
150				   "Only one `--hbh-not-strict' allowed");
151		if ( !(*flags & IP6T_OPTS_OPTS) )
152			exit_error(PARAMETER_PROBLEM,
153				   "`--hbh-opts ...' required before `--hbh-not-strict'");
154		optinfo->flags |= IP6T_OPTS_NSTRICT;
155		*flags |= IP6T_OPTS_NSTRICT;
156		break;
157	default:
158		return 0;
159	}
160
161	return 1;
162}
163
164static void
165print_options(unsigned int optsnr, u_int16_t *optsp)
166{
167	unsigned int i;
168
169	for(i=0; i<optsnr; i++){
170		printf("%d", (optsp[i] & 0xFF00)>>8);
171		if ((optsp[i] & 0x00FF) != 0x00FF){
172			printf(":%d", (optsp[i] & 0x00FF));
173		}
174		printf("%c", (i!=optsnr-1)?',':' ');
175	}
176}
177
178/* Prints out the union ip6t_matchinfo. */
179static void hbh_print(const void *ip, const struct xt_entry_match *match,
180                      int numeric)
181{
182	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
183
184	printf("hbh ");
185	if (optinfo->flags & IP6T_OPTS_LEN) {
186		printf("length");
187		printf(":%s", optinfo->invflags & IP6T_OPTS_INV_LEN ? "!" : "");
188		printf("%u", optinfo->hdrlen);
189		printf(" ");
190	}
191	if (optinfo->flags & IP6T_OPTS_OPTS) printf("opts ");
192	print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
193	if (optinfo->flags & IP6T_OPTS_NSTRICT) printf("not-strict ");
194	if (optinfo->invflags & ~IP6T_OPTS_INV_MASK)
195		printf("Unknown invflags: 0x%X ",
196		       optinfo->invflags & ~IP6T_OPTS_INV_MASK);
197}
198
199/* Saves the union ip6t_matchinfo in parsable form to stdout. */
200static void hbh_save(const void *ip, const struct xt_entry_match *match)
201{
202	const struct ip6t_opts *optinfo = (struct ip6t_opts *)match->data;
203
204	if (optinfo->flags & IP6T_OPTS_LEN) {
205		printf("--hbh-len %s%u ",
206			(optinfo->invflags & IP6T_OPTS_INV_LEN) ? "! " : "",
207			optinfo->hdrlen);
208	}
209
210	if (optinfo->flags & IP6T_OPTS_OPTS)
211		printf("--hbh-opts ");
212	print_options(optinfo->optsnr, (u_int16_t *)optinfo->opts);
213	if (optinfo->flags & IP6T_OPTS_NSTRICT)
214		printf("--hbh-not-strict ");
215}
216
217static struct ip6tables_match hbh_match6 = {
218	.name 		= "hbh",
219	.version	= IPTABLES_VERSION,
220	.size		= IP6T_ALIGN(sizeof(struct ip6t_opts)),
221	.userspacesize	= IP6T_ALIGN(sizeof(struct ip6t_opts)),
222	.help		= hbh_help,
223	.init		= hbh_init,
224	.parse		= hbh_parse,
225	.print		= hbh_print,
226	.save		= hbh_save,
227	.extra_opts	= hbh_opts,
228};
229
230void
231_init(void)
232{
233	register_match6(&hbh_match6);
234}
235