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      1 /* Shared library add-on to ip6tables to add customized REJECT support.
      2  *
      3  * (C) 2000 Jozsef Kadlecsik <kadlec (at) blackhole.kfki.hu>
      4  *
      5  * ported to IPv6 by Harald Welte <laforge (at) gnumonks.org>
      6  *
      7  */
      8 #include <stdio.h>
      9 #include <string.h>
     10 #include <xtables.h>
     11 #include <linux/netfilter_ipv6/ip6t_REJECT.h>
     12 
     13 struct reject_names {
     14 	const char *name;
     15 	const char *alias;
     16 	enum ip6t_reject_with with;
     17 	const char *desc;
     18 };
     19 
     20 enum {
     21 	O_REJECT_WITH = 0,
     22 };
     23 
     24 static const struct reject_names reject_table[] = {
     25 	{"icmp6-no-route", "no-route",
     26 		IP6T_ICMP6_NO_ROUTE, "ICMPv6 no route"},
     27 	{"icmp6-adm-prohibited", "adm-prohibited",
     28 		IP6T_ICMP6_ADM_PROHIBITED, "ICMPv6 administratively prohibited"},
     29 #if 0
     30 	{"icmp6-not-neighbor", "not-neighbor"},
     31 		IP6T_ICMP6_NOT_NEIGHBOR, "ICMPv6 not a neighbor"},
     32 #endif
     33 	{"icmp6-addr-unreachable", "addr-unreach",
     34 		IP6T_ICMP6_ADDR_UNREACH, "ICMPv6 address unreachable"},
     35 	{"icmp6-port-unreachable", "port-unreach",
     36 		IP6T_ICMP6_PORT_UNREACH, "ICMPv6 port unreachable"},
     37 	{"tcp-reset", "tcp-reset",
     38 		IP6T_TCP_RESET, "TCP RST packet"}
     39 };
     40 
     41 static void
     42 print_reject_types(void)
     43 {
     44 	unsigned int i;
     45 
     46 	printf("Valid reject types:\n");
     47 
     48 	for (i = 0; i < ARRAY_SIZE(reject_table); ++i) {
     49 		printf("    %-25s\t%s\n", reject_table[i].name, reject_table[i].desc);
     50 		printf("    %-25s\talias\n", reject_table[i].alias);
     51 	}
     52 	printf("\n");
     53 }
     54 
     55 static void REJECT_help(void)
     56 {
     57 	printf(
     58 "REJECT target options:\n"
     59 "--reject-with type              drop input packet and send back\n"
     60 "                                a reply packet according to type:\n");
     61 
     62 	print_reject_types();
     63 }
     64 
     65 static const struct xt_option_entry REJECT_opts[] = {
     66 	{.name = "reject-with", .id = O_REJECT_WITH, .type = XTTYPE_STRING},
     67 	XTOPT_TABLEEND,
     68 };
     69 
     70 static void REJECT_init(struct xt_entry_target *t)
     71 {
     72 	struct ip6t_reject_info *reject = (struct ip6t_reject_info *)t->data;
     73 
     74 	/* default */
     75 	reject->with = IP6T_ICMP6_PORT_UNREACH;
     76 
     77 }
     78 
     79 static void REJECT_parse(struct xt_option_call *cb)
     80 {
     81 	struct ip6t_reject_info *reject = cb->data;
     82 	unsigned int i;
     83 
     84 	xtables_option_parse(cb);
     85 	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
     86 		if (strncasecmp(reject_table[i].name,
     87 		      cb->arg, strlen(cb->arg)) == 0 ||
     88 		    strncasecmp(reject_table[i].alias,
     89 		      cb->arg, strlen(cb->arg)) == 0) {
     90 			reject->with = reject_table[i].with;
     91 			return;
     92 		}
     93 	xtables_error(PARAMETER_PROBLEM,
     94 		"unknown reject type \"%s\"", cb->arg);
     95 }
     96 
     97 static void REJECT_print(const void *ip, const struct xt_entry_target *target,
     98                          int numeric)
     99 {
    100 	const struct ip6t_reject_info *reject
    101 		= (const struct ip6t_reject_info *)target->data;
    102 	unsigned int i;
    103 
    104 	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
    105 		if (reject_table[i].with == reject->with)
    106 			break;
    107 	printf(" reject-with %s", reject_table[i].name);
    108 }
    109 
    110 static void REJECT_save(const void *ip, const struct xt_entry_target *target)
    111 {
    112 	const struct ip6t_reject_info *reject
    113 		= (const struct ip6t_reject_info *)target->data;
    114 	unsigned int i;
    115 
    116 	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
    117 		if (reject_table[i].with == reject->with)
    118 			break;
    119 
    120 	printf(" --reject-with %s", reject_table[i].name);
    121 }
    122 
    123 static struct xtables_target reject_tg6_reg = {
    124 	.name = "REJECT",
    125 	.version	= XTABLES_VERSION,
    126 	.family		= NFPROTO_IPV6,
    127 	.size 		= XT_ALIGN(sizeof(struct ip6t_reject_info)),
    128 	.userspacesize 	= XT_ALIGN(sizeof(struct ip6t_reject_info)),
    129 	.help		= REJECT_help,
    130 	.init		= REJECT_init,
    131 	.print		= REJECT_print,
    132 	.save		= REJECT_save,
    133 	.x6_parse	= REJECT_parse,
    134 	.x6_options	= REJECT_opts,
    135 };
    136 
    137 void _init(void)
    138 {
    139 	xtables_register_target(&reject_tg6_reg);
    140 }
    141