/*
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* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
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*
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* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6 NAT
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* funded by Astaro.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <xtables.h>
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#include <limits.h> /* INT_MAX in ip_tables.h */
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter/nf_nat.h>
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enum {
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O_TO_PORTS = 0,
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O_RANDOM,
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F_TO_PORTS = 1 << O_TO_PORTS,
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F_RANDOM = 1 << O_RANDOM,
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};
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static void REDIRECT_help(void)
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{
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printf(
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"REDIRECT target options:\n"
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" --to-ports <port>[-<port>]\n"
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" Port (range) to map to.\n"
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" [--random]\n");
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}
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static const struct xt_option_entry REDIRECT_opts[] = {
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{.name = "to-ports", .id = O_TO_PORTS, .type = XTTYPE_STRING},
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{.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE},
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XTOPT_TABLEEND,
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};
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/* Parses ports */
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static void
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parse_ports(const char *arg, struct nf_nat_range *range)
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{
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char *end = "";
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unsigned int port, maxport;
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range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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if (!xtables_strtoui(arg, &end, &port, 0, UINT16_MAX) &&
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(port = xtables_service_to_port(arg, NULL)) == (unsigned)-1)
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xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
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switch (*end) {
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case '\0':
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range->min_proto.tcp.port
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= range->max_proto.tcp.port
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= htons(port);
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return;
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case '-':
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if (!xtables_strtoui(end + 1, NULL, &maxport, 0, UINT16_MAX) &&
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(maxport = xtables_service_to_port(end + 1, NULL)) == (unsigned)-1)
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break;
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if (maxport < port)
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break;
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range->min_proto.tcp.port = htons(port);
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range->max_proto.tcp.port = htons(maxport);
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return;
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default:
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break;
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}
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xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
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}
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static void REDIRECT_parse(struct xt_option_call *cb)
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{
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const struct ip6t_entry *entry = cb->xt_entry;
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struct nf_nat_range *range = (void *)(*cb->target)->data;
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int portok;
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if (entry->ipv6.proto == IPPROTO_TCP
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|| entry->ipv6.proto == IPPROTO_UDP
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|| entry->ipv6.proto == IPPROTO_SCTP
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|| entry->ipv6.proto == IPPROTO_DCCP
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|| entry->ipv6.proto == IPPROTO_ICMP)
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portok = 1;
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else
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portok = 0;
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xtables_option_parse(cb);
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switch (cb->entry->id) {
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case O_TO_PORTS:
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if (!portok)
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xtables_error(PARAMETER_PROBLEM,
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"Need TCP, UDP, SCTP or DCCP with port specification");
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parse_ports(cb->arg, range);
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if (cb->xflags & F_RANDOM)
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range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
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break;
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case O_RANDOM:
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if (cb->xflags & F_TO_PORTS)
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range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
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break;
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}
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}
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static void REDIRECT_print(const void *ip, const struct xt_entry_target *target,
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int numeric)
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{
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const struct nf_nat_range *range = (const void *)target->data;
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
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printf(" redir ports ");
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printf("%hu", ntohs(range->min_proto.tcp.port));
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if (range->max_proto.tcp.port != range->min_proto.tcp.port)
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printf("-%hu", ntohs(range->max_proto.tcp.port));
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if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
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printf(" random");
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}
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}
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static void REDIRECT_save(const void *ip, const struct xt_entry_target *target)
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{
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const struct nf_nat_range *range = (const void *)target->data;
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
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printf(" --to-ports ");
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printf("%hu", ntohs(range->min_proto.tcp.port));
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if (range->max_proto.tcp.port != range->min_proto.tcp.port)
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printf("-%hu", ntohs(range->max_proto.tcp.port));
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if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
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printf(" --random");
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}
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}
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static int REDIRECT_xlate(struct xt_xlate *xl,
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const struct xt_xlate_tg_params *params)
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{
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const struct nf_nat_range *range = (const void *)params->target->data;
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
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xt_xlate_add(xl, "redirect to :%hu",
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ntohs(range->min_proto.tcp.port));
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if (range->max_proto.tcp.port != range->min_proto.tcp.port)
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xt_xlate_add(xl, "-%hu ",
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ntohs(range->max_proto.tcp.port));
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if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
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xt_xlate_add(xl, " random ");
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}
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return 1;
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}
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static struct xtables_target redirect_tg_reg = {
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.name = "REDIRECT",
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.version = XTABLES_VERSION,
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.family = NFPROTO_IPV6,
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.size = XT_ALIGN(sizeof(struct nf_nat_range)),
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.userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)),
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.help = REDIRECT_help,
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.x6_parse = REDIRECT_parse,
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.print = REDIRECT_print,
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.save = REDIRECT_save,
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.x6_options = REDIRECT_opts,
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.xlate = REDIRECT_xlate,
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};
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void _init(void)
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{
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xtables_register_target(&redirect_tg_reg);
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}
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