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-rw-r--r--extensions/libip6t_REDIRECT.c151
1 files changed, 151 insertions, 0 deletions
diff --git a/extensions/libip6t_REDIRECT.c b/extensions/libip6t_REDIRECT.c
new file mode 100644
index 00000000..1724aa67
--- /dev/null
+++ b/extensions/libip6t_REDIRECT.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
+ *
+ * Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6 NAT
+ * funded by Astaro.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <xtables.h>
+#include <limits.h> /* INT_MAX in ip_tables.h */
+#include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter/nf_nat.h>
+
+enum {
+ O_TO_PORTS = 0,
+ O_RANDOM,
+ F_TO_PORTS = 1 << O_TO_PORTS,
+ F_RANDOM = 1 << O_RANDOM,
+};
+
+static void REDIRECT_help(void)
+{
+ printf(
+"REDIRECT target options:\n"
+" --to-ports <port>[-<port>]\n"
+" Port (range) to map to.\n"
+" [--random]\n");
+}
+
+static const struct xt_option_entry REDIRECT_opts[] = {
+ {.name = "to-ports", .id = O_TO_PORTS, .type = XTTYPE_STRING},
+ {.name = "random", .id = O_RANDOM, .type = XTTYPE_NONE},
+ XTOPT_TABLEEND,
+};
+
+/* Parses ports */
+static void
+parse_ports(const char *arg, struct nf_nat_range *range)
+{
+ char *end = "";
+ unsigned int port, maxport;
+
+ range->flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
+
+ if (!xtables_strtoui(arg, &end, &port, 0, UINT16_MAX) &&
+ (port = xtables_service_to_port(arg, NULL)) == (unsigned)-1)
+ xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
+
+ switch (*end) {
+ case '\0':
+ range->min_proto.tcp.port
+ = range->max_proto.tcp.port
+ = htons(port);
+ return;
+ case '-':
+ if (!xtables_strtoui(end + 1, NULL, &maxport, 0, UINT16_MAX) &&
+ (maxport = xtables_service_to_port(end + 1, NULL)) == (unsigned)-1)
+ break;
+
+ if (maxport < port)
+ break;
+
+ range->min_proto.tcp.port = htons(port);
+ range->max_proto.tcp.port = htons(maxport);
+ return;
+ default:
+ break;
+ }
+ xtables_param_act(XTF_BAD_VALUE, "REDIRECT", "--to-ports", arg);
+}
+
+static void REDIRECT_parse(struct xt_option_call *cb)
+{
+ const struct ip6t_entry *entry = cb->xt_entry;
+ struct nf_nat_range *range = (void *)(*cb->target)->data;
+ int portok;
+
+ if (entry->ipv6.proto == IPPROTO_TCP
+ || entry->ipv6.proto == IPPROTO_UDP
+ || entry->ipv6.proto == IPPROTO_SCTP
+ || entry->ipv6.proto == IPPROTO_DCCP
+ || entry->ipv6.proto == IPPROTO_ICMP)
+ portok = 1;
+ else
+ portok = 0;
+
+ xtables_option_parse(cb);
+ switch (cb->entry->id) {
+ case O_TO_PORTS:
+ if (!portok)
+ xtables_error(PARAMETER_PROBLEM,
+ "Need TCP, UDP, SCTP or DCCP with port specification");
+ parse_ports(cb->arg, range);
+ if (cb->xflags & F_RANDOM)
+ range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
+ break;
+ case O_RANDOM:
+ if (cb->xflags & F_TO_PORTS)
+ range->flags |= NF_NAT_RANGE_PROTO_RANDOM;
+ break;
+ }
+}
+
+static void REDIRECT_print(const void *ip, const struct xt_entry_target *target,
+ int numeric)
+{
+ const struct nf_nat_range *range = (const void *)target->data;
+
+ if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+ printf(" redir ports ");
+ printf("%hu", ntohs(range->min_proto.tcp.port));
+ if (range->max_proto.tcp.port != range->min_proto.tcp.port)
+ printf("-%hu", ntohs(range->max_proto.tcp.port));
+ if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
+ printf(" random");
+ }
+}
+
+static void REDIRECT_save(const void *ip, const struct xt_entry_target *target)
+{
+ const struct nf_nat_range *range = (const void *)target->data;
+
+ if (range->flags & NF_NAT_RANGE_PROTO_SPECIFIED) {
+ printf(" --to-ports ");
+ printf("%hu", ntohs(range->min_proto.tcp.port));
+ if (range->max_proto.tcp.port != range->min_proto.tcp.port)
+ printf("-%hu", ntohs(range->max_proto.tcp.port));
+ if (range->flags & NF_NAT_RANGE_PROTO_RANDOM)
+ printf(" --random");
+ }
+}
+
+static struct xtables_target redirect_tg_reg = {
+ .name = "REDIRECT",
+ .version = XTABLES_VERSION,
+ .family = NFPROTO_IPV6,
+ .size = XT_ALIGN(sizeof(struct nf_nat_range)),
+ .userspacesize = XT_ALIGN(sizeof(struct nf_nat_range)),
+ .help = REDIRECT_help,
+ .x6_parse = REDIRECT_parse,
+ .print = REDIRECT_print,
+ .save = REDIRECT_save,
+ .x6_options = REDIRECT_opts,
+};
+
+void _init(void)
+{
+ xtables_register_target(&redirect_tg_reg);
+}