summaryrefslogtreecommitdiffstats
path: root/extensions/libipt_ROUTE.c
blob: c17bf5df312ab06fb507443b33ad49e23030427a (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
/* Shared library add-on to iptables to add ROUTE target support.
 * Author : Cédric de Launois, <delaunois@info.ucl.ac.be>
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <iptables.h>
#include <net/if.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_ROUTE.h>

/* Function which prints out usage message. */
static void
help(void)
{
	printf(
"ROUTE target v%s options:\n"
"  --oif   \tifname \t\tSend the packet out using `ifname' network interface\n"
"  --iif   \tifname \t\tChange the packet's incoming interface to `ifname'\n"
"  --gw    \tip     \t\tRoute the packet via this gateway\n"
"\n",
IPTABLES_VERSION);
}

static struct option opts[] = {
	{ "oif", 1, 0, '1' },
	{ "iif", 1, 0, '2' },
	{ "gw", 1, 0, '3' },
	{ 0 }
};

/* Initialize the target. */
static void
init(struct ipt_entry_target *t, unsigned int *nfcache)
{
	struct ipt_route_target_info *route_info = 
		(struct ipt_route_target_info*)t->data;

	route_info->oif[0] = '\0';
	route_info->iif[0] = '\0';
	route_info->gw = 0;
}


#define IPT_ROUTE_OPT_IF       0x01
#define IPT_ROUTE_OPT_GW       0x02

/* 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,
      struct ipt_entry_target **target)
{
	struct ipt_route_target_info *route_info = 
		(struct ipt_route_target_info*)(*target)->data;

	switch (c) {
	case '1':
		if (*flags & IPT_ROUTE_OPT_IF)
			exit_error(PARAMETER_PROBLEM,
				   "Can't specify --oif twice or --oif with --iif");

		if (check_inverse(optarg, &invert, NULL, 0))
			exit_error(PARAMETER_PROBLEM,
				   "Unexpected `!' after --oif");

		if (strlen(optarg) > sizeof(route_info->oif) - 1)
			exit_error(PARAMETER_PROBLEM,
				   "Maximum interface name length %u",
				   sizeof(route_info->oif) - 1);

		strcpy(route_info->oif, optarg);
		*flags |= IPT_ROUTE_OPT_IF;
		break;

	case '2':
		if (*flags & IPT_ROUTE_OPT_IF)
			exit_error(PARAMETER_PROBLEM,
				   "Can't specify --iif twice or --iif with --oif");

		if (check_inverse(optarg, &invert, NULL, 0))
			exit_error(PARAMETER_PROBLEM,
				   "Unexpected `!' after --iif");

		if (strlen(optarg) > sizeof(route_info->iif) - 1)
			exit_error(PARAMETER_PROBLEM,
				   "Maximum interface name length %u",
				   sizeof(route_info->iif) - 1);

		strcpy(route_info->iif, optarg);
		*flags |= IPT_ROUTE_OPT_IF;
		break;

	case '3':
		if (*flags & IPT_ROUTE_OPT_GW)
			exit_error(PARAMETER_PROBLEM,
				   "Can't specify --gw twice");

		if (!inet_aton(optarg, (struct in_addr*)&route_info->gw)) {
			exit_error(PARAMETER_PROBLEM,
				   "Invalid IP address %s",
				   optarg);
		}

		*flags |= IPT_ROUTE_OPT_GW;
		break;

	default:
		return 0;
	}

	return 1;
}


static void
final_check(unsigned int flags)
{
	if (!flags)
		exit_error(PARAMETER_PROBLEM,
		           "ROUTE target: one parameter is required");
}


/* Prints out the targinfo. */
static void
print(const struct ipt_ip *ip,
      const struct ipt_entry_target *target,
      int numeric)
{
	const struct ipt_route_target_info *route_info
		= (const struct ipt_route_target_info *)target->data;

	printf("ROUTE ");

	if (route_info->oif[0])
		printf("oif %s ", route_info->oif);

	if (route_info->iif[0])
		printf("iif %s ", route_info->iif);

	if (route_info->gw) {
		struct in_addr ip = { route_info->gw };
		printf("gw %s ", inet_ntoa(ip));
	}
}


static void save(const struct ipt_ip *ip, 
		 const struct ipt_entry_target *target)
{
	const struct ipt_route_target_info *route_info
		= (const struct ipt_route_target_info *)target->data;

	if (route_info->oif[0])
		printf("--oif %s ", route_info->oif);

	if (route_info->iif[0])
		printf("--iif %s ", route_info->iif);

	if (route_info->gw) {
		struct in_addr ip = { route_info->gw };
		printf("--gw %s ", inet_ntoa(ip));
	}
}


static
struct iptables_target route
= { NULL,
    "ROUTE",
    IPTABLES_VERSION,
    IPT_ALIGN(sizeof(struct ipt_route_target_info)),
    IPT_ALIGN(sizeof(struct ipt_route_target_info)),
    &help,
    &init,
    &parse,
    &final_check,
    &print,
    &save,
    opts
};

void _init(void)
{
	register_target(&route);
}