summaryrefslogtreecommitdiffstats
path: root/extensions/libipt_mport.c
blob: a387b2141439a3dcc019ed7b2e534b57402aed09 (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
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
/* Shared library add-on to iptables to add multiple TCP port support. */
#include <stdio.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <linux/netfilter_ipv4/ipt_mport.h>

/* Function which prints out usage message. */
static void
help(void)
{
	printf(
"mport v%s options:\n"
" --source-ports port[,port:port,port...]\n"
" --sports ...\n"
"				match source port(s)\n"
" --destination-ports port[,port:port,port...]\n"
" --dports ...\n"
"				match destination port(s)\n"
" --ports port[,port:port,port]\n"
"				match both source and destination port(s)\n",
IPTABLES_VERSION);
}

static struct option opts[] = {
	{ "source-ports", 1, 0, '1' },
	{ "sports", 1, 0, '1' }, /* synonym */
	{ "destination-ports", 1, 0, '2' },
	{ "dports", 1, 0, '2' }, /* synonym */
	{ "ports", 1, 0, '3' },
	{0}
};

static int
service_to_port(const char *name, const char *proto)
{
	struct servent *service;

	if ((service = getservbyname(name, proto)) != NULL)
		return ntohs((unsigned short) service->s_port);

		return -1;
}

static u_int16_t
parse_port(const char *port, const char *proto)
{
	unsigned int portnum;

	if (string_to_number(port, 0, 65535, &portnum) != -1 ||
	    (portnum = service_to_port(port, proto)) != -1)
		return (u_int16_t)portnum;

	exit_error(PARAMETER_PROBLEM,
		   "invalid port/service `%s' specified", port);
}

static void
parse_multi_ports(const char *portstring, struct ipt_mport *minfo,
                  const char *proto)
{
	char *buffer, *cp, *next, *range;
	unsigned int i;
        u_int16_t m;

	buffer = strdup(portstring);
	if (!buffer) exit_error(OTHER_PROBLEM, "strdup failed");

        minfo->pflags = 0;

	for (cp=buffer, i=0, m=1; cp && i<IPT_MULTI_PORTS; cp=next,i++,m<<=1)
	{
		next=strchr(cp, ',');
		if (next) *next++='\0';
                range = strchr(cp, ':');
                if (range) {
                        if (i == IPT_MULTI_PORTS-1)
                                exit_error(PARAMETER_PROBLEM,
                                           "too many ports specified");
                        *range++ = '\0';
                }
		minfo->ports[i] = parse_port(cp, proto);
                if (range) {
                        minfo->pflags |= m;
                        minfo->ports[++i] = parse_port(range, proto);
                        if (minfo->ports[i-1] >= minfo->ports[i])
                                exit_error(PARAMETER_PROBLEM,
                                           "invalid portrange specified");
                        m <<= 1;
                }
	}
	if (cp) exit_error(PARAMETER_PROBLEM, "too many ports specified");
        if (i == IPT_MULTI_PORTS-1)
                minfo->ports[i] = minfo->ports[i-1];
        else if (i < IPT_MULTI_PORTS-1) {
                minfo->ports[i] = ~0;
                minfo->pflags |= 1<<i;
        }
	free(buffer);
}

/* Initialize the match. */
static void
init(struct ipt_entry_match *m, unsigned int *nfcache)
{
}

static const char *
check_proto(const struct ipt_entry *entry)
{
	if (entry->ip.proto == IPPROTO_TCP)
		return "tcp";
	else if (entry->ip.proto == IPPROTO_UDP)
		return "udp";
	else if (!entry->ip.proto)
		exit_error(PARAMETER_PROBLEM,
			   "multiport needs `-p tcp' or `-p udp'");
	else
		exit_error(PARAMETER_PROBLEM,
			   "multiport only works with TCP or UDP");
}

/* Function which parses command options; returns true if it
   ate an option */
static int
parse(int c, char **argv, int invert, unsigned int *flags,
      const struct ipt_entry *entry,
      unsigned int *nfcache,
      struct ipt_entry_match **match)
{
	const char *proto;
	struct ipt_mport *minfo
		= (struct ipt_mport *)(*match)->data;

	switch (c) {
	case '1':
		check_inverse(argv[optind-1], &invert, &optind, 0);
		proto = check_proto(entry);
		parse_multi_ports(argv[optind-1], minfo, proto);
		minfo->flags = IPT_MPORT_SOURCE;
		break;

	case '2':
		check_inverse(argv[optind-1], &invert, &optind, 0);
		proto = check_proto(entry);
		parse_multi_ports(argv[optind-1], minfo, proto);
		minfo->flags = IPT_MPORT_DESTINATION;
		break;

	case '3':
		check_inverse(argv[optind-1], &invert, &optind, 0);
		proto = check_proto(entry);
		parse_multi_ports(argv[optind-1], minfo, proto);
		minfo->flags = IPT_MPORT_EITHER;
		break;

	default:
		return 0;
	}

	if (invert)
		exit_error(PARAMETER_PROBLEM,
			   "multiport does not support invert");

	if (*flags)
		exit_error(PARAMETER_PROBLEM,
			   "multiport can only have one option");
	*flags = 1;
	return 1;
}

/* Final check; must specify something. */
static void
final_check(unsigned int flags)
{
	if (!flags)
		exit_error(PARAMETER_PROBLEM, "mport expects an option");
}

static char *
port_to_service(int port, u_int8_t proto)
{
	struct servent *service;

	if ((service = getservbyport(htons(port),
				     proto == IPPROTO_TCP ? "tcp" : "udp")))
		return service->s_name;

	return NULL;
}

static void
print_port(u_int16_t port, u_int8_t protocol, int numeric)
{
	char *service;

	if (numeric || (service = port_to_service(port, protocol)) == NULL)
		printf("%u", port);
	else
		printf("%s", service);
}

/* Prints out the matchinfo. */
static void
print(const struct ipt_ip *ip,
      const struct ipt_entry_match *match,
      int numeric)
{
	const struct ipt_mport *minfo
		= (const struct ipt_mport *)match->data;
	unsigned int i;
        u_int16_t pflags = minfo->pflags;

	printf("mport ");

	switch (minfo->flags) {
	case IPT_MPORT_SOURCE:
		printf("sports ");
		break;

	case IPT_MPORT_DESTINATION:
		printf("dports ");
		break;

	case IPT_MPORT_EITHER:
		printf("ports ");
		break;

	default:
		printf("ERROR ");
		break;
	}

	for (i=0; i < IPT_MULTI_PORTS; i++) {
                if (pflags & (1<<i)
                    && minfo->ports[i] == 65535)
                        break;
                if (i == IPT_MULTI_PORTS-1
                    && minfo->ports[i-1] == minfo->ports[i])
                        break;
		printf("%s", i ? "," : "");
		print_port(minfo->ports[i], ip->proto, numeric);
                if (pflags & (1<<i)) {
                        printf(":");
                        print_port(minfo->ports[++i], ip->proto, numeric);
                }
	}
	printf(" ");
}

/* Saves the union ipt_matchinfo in parsable form to stdout. */
static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match)
{
	const struct ipt_mport *minfo
		= (const struct ipt_mport *)match->data;
	unsigned int i;
        u_int16_t pflags = minfo->pflags;

	switch (minfo->flags) {
	case IPT_MPORT_SOURCE:
		printf("--sports ");
		break;

	case IPT_MPORT_DESTINATION:
		printf("--dports ");
		break;

	case IPT_MPORT_EITHER:
		printf("--ports ");
		break;
	}

	for (i=0; i < IPT_MULTI_PORTS; i++) {
                if (pflags & (1<<i)
                    && minfo->ports[i] == 65535)
                        break;
                if (i == IPT_MULTI_PORTS-1
                    && minfo->ports[i-1] == minfo->ports[i])
                        break;
		printf("%s", i ? "," : "");
		print_port(minfo->ports[i], ip->proto, 1);
                if (pflags & (1<<i)) {
                        printf(":");
                        print_port(minfo->ports[++i], ip->proto, 1);
                }
	}
	printf(" ");
}

static struct iptables_match mport = { 
	.next		= NULL,
	.name		= "mport",
	.version	= IPTABLES_VERSION,
	.size		= IPT_ALIGN(sizeof(struct ipt_mport)),
	.userspacesize	= IPT_ALIGN(sizeof(struct ipt_mport)),
	.help		= &help,
	.init		= &init,
	.parse		= &parse,
	.final_check	= &final_check,
	.print		= &print,
	.save		= &save,
	.extra_opts	= opts
};

void
_init(void)
{
	register_match(&mport);
}