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412 lines
10 KiB
412 lines
10 KiB
/*
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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 DNAT 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 <netdb.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 <iptables.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_DEST = 0,
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O_RANDOM,
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O_PERSISTENT,
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O_X_TO_DEST,
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F_TO_DEST = 1 << O_TO_DEST,
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F_RANDOM = 1 << O_RANDOM,
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F_X_TO_DEST = 1 << O_X_TO_DEST,
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};
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static void DNAT_help(void)
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{
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printf(
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"DNAT target options:\n"
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" --to-destination [<ipaddr>[-<ipaddr>]][:port[-port]]\n"
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" Address to map destination to.\n"
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"[--random] [--persistent]\n");
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}
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static void DNAT_help_v2(void)
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{
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printf(
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"DNAT target options:\n"
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" --to-destination [<ipaddr>[-<ipaddr>]][:port[-port[/port]]]\n"
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" Address to map destination to.\n"
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"[--random] [--persistent]\n");
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}
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static const struct xt_option_entry DNAT_opts[] = {
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{.name = "to-destination", .id = O_TO_DEST, .type = XTTYPE_STRING,
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.flags = XTOPT_MAND | XTOPT_MULTI},
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{.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE},
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{.name = "persistent", .id = O_PERSISTENT, .type = XTTYPE_NONE},
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XTOPT_TABLEEND,
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};
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/* Ranges expected in network order. */
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static void
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parse_to(const char *orig_arg, int portok, struct nf_nat_range2 *range, int rev)
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{
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char *arg, *start, *end = NULL, *colon = NULL, *dash, *error;
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const struct in6_addr *ip;
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arg = strdup(orig_arg);
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if (arg == NULL)
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xtables_error(RESOURCE_PROBLEM, "strdup");
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start = strchr(arg, '[');
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if (start == NULL) {
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start = arg;
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/* Lets assume one colon is port information. Otherwise its an IPv6 address */
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colon = strchr(arg, ':');
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if (colon && strchr(colon+1, ':'))
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colon = NULL;
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}
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else {
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start++;
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end = strchr(start, ']');
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if (end == NULL)
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xtables_error(PARAMETER_PROBLEM,
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"Invalid address format");
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*end = '\0';
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colon = strchr(end + 1, ':');
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}
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if (colon) {
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int port;
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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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range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
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port = atoi(colon+1);
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if (port <= 0 || port > 65535)
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xtables_error(PARAMETER_PROBLEM,
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"Port `%s' not valid\n", colon+1);
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error = strchr(colon+1, ':');
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if (error)
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xtables_error(PARAMETER_PROBLEM,
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"Invalid port:port syntax - use dash\n");
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dash = strchr(colon, '-');
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if (!dash) {
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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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} else {
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int maxport;
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maxport = atoi(dash + 1);
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if (maxport <= 0 || maxport > 65535)
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xtables_error(PARAMETER_PROBLEM,
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"Port `%s' not valid\n", dash+1);
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if (maxport < port)
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/* People are stupid. */
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xtables_error(PARAMETER_PROBLEM,
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"Port range `%s' funky\n", colon+1);
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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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if (rev >= 2) {
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char *slash = strchr(dash, '/');
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if (slash) {
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int baseport;
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baseport = atoi(slash + 1);
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if (baseport <= 0 || baseport > 65535)
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xtables_error(PARAMETER_PROBLEM,
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"Port `%s' not valid\n", slash+1);
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range->flags |= NF_NAT_RANGE_PROTO_OFFSET;
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range->base_proto.tcp.port = htons(baseport);
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}
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}
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}
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/* Starts with colon or [] colon? No IP info...*/
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if (colon == arg || colon == arg+2) {
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free(arg);
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return;
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}
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*colon = '\0';
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}
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range->flags |= NF_NAT_RANGE_MAP_IPS;
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dash = strchr(start, '-');
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if (colon && dash && dash > colon)
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dash = NULL;
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if (dash)
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*dash = '\0';
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ip = xtables_numeric_to_ip6addr(start);
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if (!ip)
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xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n",
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start);
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range->min_addr.in6 = *ip;
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if (dash) {
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ip = xtables_numeric_to_ip6addr(dash + 1);
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if (!ip)
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xtables_error(PARAMETER_PROBLEM, "Bad IP address \"%s\"\n",
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dash+1);
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range->max_addr.in6 = *ip;
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} else
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range->max_addr = range->min_addr;
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free(arg);
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return;
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}
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static void _DNAT_parse(struct xt_option_call *cb,
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struct nf_nat_range2 *range, int rev)
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{
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const struct ip6t_entry *entry = cb->xt_entry;
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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_DEST:
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if (cb->xflags & F_X_TO_DEST) {
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xtables_error(PARAMETER_PROBLEM,
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"DNAT: Multiple --to-destination not supported");
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}
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parse_to(cb->arg, portok, range, rev);
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cb->xflags |= F_X_TO_DEST;
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break;
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case O_PERSISTENT:
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range->flags |= NF_NAT_RANGE_PERSISTENT;
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break;
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}
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}
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static void DNAT_parse(struct xt_option_call *cb)
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{
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struct nf_nat_range *range_v1 = (void *)cb->data;
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struct nf_nat_range2 range = {};
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memcpy(&range, range_v1, sizeof(*range_v1));
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_DNAT_parse(cb, &range, 1);
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memcpy(range_v1, &range, sizeof(*range_v1));
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}
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static void DNAT_parse_v2(struct xt_option_call *cb)
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{
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_DNAT_parse(cb, (struct nf_nat_range2 *)cb->data, 2);
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}
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static void _DNAT_fcheck(struct xt_fcheck_call *cb, unsigned int *flags)
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{
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static const unsigned int f = F_TO_DEST | F_RANDOM;
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if ((cb->xflags & f) == f)
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*flags |= NF_NAT_RANGE_PROTO_RANDOM;
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}
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static void DNAT_fcheck(struct xt_fcheck_call *cb)
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{
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_DNAT_fcheck(cb, &((struct nf_nat_range *)cb->data)->flags);
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}
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static void DNAT_fcheck_v2(struct xt_fcheck_call *cb)
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{
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_DNAT_fcheck(cb, &((struct nf_nat_range2 *)cb->data)->flags);
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}
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static void print_range(const struct nf_nat_range2 *range, int rev)
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{
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if (range->flags & NF_NAT_RANGE_MAP_IPS) {
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)
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printf("[");
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printf("%s", xtables_ip6addr_to_numeric(&range->min_addr.in6));
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if (memcmp(&range->min_addr, &range->max_addr,
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sizeof(range->min_addr)))
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printf("-%s", xtables_ip6addr_to_numeric(&range->max_addr.in6));
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)
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printf("]");
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}
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if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
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printf(":");
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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 (rev >= 2 && (range->flags & NF_NAT_RANGE_PROTO_OFFSET))
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printf("/%hu", ntohs(range->base_proto.tcp.port));
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}
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}
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static void _DNAT_print(const struct nf_nat_range2 *range, int rev)
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{
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printf(" to:");
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print_range(range, rev);
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if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
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printf(" random");
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if (range->flags & NF_NAT_RANGE_PERSISTENT)
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printf(" persistent");
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}
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static void DNAT_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_v1 = (const void *)target->data;
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struct nf_nat_range2 range = {};
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memcpy(&range, range_v1, sizeof(*range_v1));
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_DNAT_print(&range, 1);
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}
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static void DNAT_print_v2(const void *ip, const struct xt_entry_target *target,
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int numeric)
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{
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_DNAT_print((const struct nf_nat_range2 *)target->data, 2);
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}
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static void _DNAT_save(const struct nf_nat_range2 *range, int rev)
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{
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printf(" --to-destination ");
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print_range(range, rev);
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if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
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printf(" --random");
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if (range->flags & NF_NAT_RANGE_PERSISTENT)
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printf(" --persistent");
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}
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static void DNAT_save(const void *ip, const struct xt_entry_target *target)
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{
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const struct nf_nat_range *range_v1 = (const void *)target->data;
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struct nf_nat_range2 range = {};
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memcpy(&range, range_v1, sizeof(*range_v1));
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_DNAT_save(&range, 1);
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}
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static void DNAT_save_v2(const void *ip, const struct xt_entry_target *target)
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{
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_DNAT_save((const struct nf_nat_range2 *)target->data, 2);
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}
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static void print_range_xlate(const struct nf_nat_range2 *range,
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struct xt_xlate *xl, int rev)
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{
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bool proto_specified = range->flags & NF_NAT_RANGE_PROTO_SPECIFIED;
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if (range->flags & NF_NAT_RANGE_MAP_IPS) {
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xt_xlate_add(xl, "%s%s%s",
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proto_specified ? "[" : "",
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xtables_ip6addr_to_numeric(&range->min_addr.in6),
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proto_specified ? "]" : "");
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if (memcmp(&range->min_addr, &range->max_addr,
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sizeof(range->min_addr))) {
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xt_xlate_add(xl, "-%s%s%s",
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proto_specified ? "[" : "",
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xtables_ip6addr_to_numeric(&range->max_addr.in6),
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proto_specified ? "]" : "");
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}
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}
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if (proto_specified) {
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xt_xlate_add(xl, ":%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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xt_xlate_add(xl, "-%hu",
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ntohs(range->max_proto.tcp.port));
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}
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}
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static int _DNAT_xlate(struct xt_xlate *xl,
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const struct nf_nat_range2 *range, int rev)
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{
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bool sep_need = false;
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const char *sep = " ";
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xt_xlate_add(xl, "dnat to ");
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print_range_xlate(range, xl, rev);
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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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sep_need = true;
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}
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if (range->flags & NF_NAT_RANGE_PERSISTENT) {
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if (sep_need)
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sep = ",";
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xt_xlate_add(xl, "%spersistent", sep);
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}
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return 1;
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}
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static int DNAT_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_v1 = (const void *)params->target->data;
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struct nf_nat_range2 range = {};
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memcpy(&range, range_v1, sizeof(*range_v1));
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_DNAT_xlate(xl, &range, 1);
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return 1;
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}
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static int DNAT_xlate_v2(struct xt_xlate *xl,
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const struct xt_xlate_tg_params *params)
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{
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_DNAT_xlate(xl, (const struct nf_nat_range2 *)params->target->data, 2);
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return 1;
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}
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static struct xtables_target dnat_tg_reg[] = {
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{
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.name = "DNAT",
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.version = XTABLES_VERSION,
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.family = NFPROTO_IPV6,
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.revision = 1,
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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 = DNAT_help,
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.print = DNAT_print,
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.save = DNAT_save,
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.x6_parse = DNAT_parse,
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.x6_fcheck = DNAT_fcheck,
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.x6_options = DNAT_opts,
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.xlate = DNAT_xlate,
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},
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{
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.name = "DNAT",
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.version = XTABLES_VERSION,
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.family = NFPROTO_IPV6,
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.revision = 2,
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.size = XT_ALIGN(sizeof(struct nf_nat_range2)),
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.userspacesize = XT_ALIGN(sizeof(struct nf_nat_range2)),
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.help = DNAT_help_v2,
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.print = DNAT_print_v2,
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.save = DNAT_save_v2,
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.x6_parse = DNAT_parse_v2,
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.x6_fcheck = DNAT_fcheck_v2,
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.x6_options = DNAT_opts,
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.xlate = DNAT_xlate_v2,
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},
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};
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void _init(void)
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{
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xtables_register_targets(dnat_tg_reg, ARRAY_SIZE(dnat_tg_reg));
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}
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