From e6869a8f59d779ff4d5a0984c86d80db70784962 Mon Sep 17 00:00:00 2001
From: Marc Boucher <marc@mbsi.ca>
Date: Mon, 20 Mar 2000 06:03:29 +0000
Subject: reorganized tree after kernel merge

---
 extensions/libipt_MASQUERADE.c | 166 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 extensions/libipt_MASQUERADE.c

(limited to 'extensions/libipt_MASQUERADE.c')

diff --git a/extensions/libipt_MASQUERADE.c b/extensions/libipt_MASQUERADE.c
new file mode 100644
index 00000000..a1151bbc
--- /dev/null
+++ b/extensions/libipt_MASQUERADE.c
@@ -0,0 +1,166 @@
+/* Shared library add-on to iptables to add masquerade support. */
+#include <stdio.h>
+#include <netdb.h>
+#include <string.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <iptables.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+
+/* Function which prints out usage message. */
+static void
+help(void)
+{
+	printf(
+"MASQUERADE v%s options:\n"
+" --to-ports <port>[-<port>]\n"
+"				Port (range) to map to.\n\n",
+NETFILTER_VERSION);
+}
+
+static struct option opts[] = {
+	{ "to-ports", 1, 0, '1' },
+	{ 0 }
+};
+
+/* Initialize the target. */
+static void
+init(struct ipt_entry_target *t, unsigned int *nfcache)
+{
+	struct ip_nat_multi_range *mr = (struct ip_nat_multi_range *)t->data;
+
+	/* Actually, it's 0, but it's ignored at the moment. */
+	mr->rangesize = 1;
+
+	/* Can't cache this */
+	*nfcache |= NFC_UNKNOWN;
+}
+
+/* Parses ports */
+static void
+parse_ports(const char *arg, struct ip_nat_multi_range *mr)
+{
+	const char *dash;
+	int port;
+
+	mr->range[0].flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+
+	port = atoi(arg);
+	if (port == 0 || port > 65535)
+		exit_error(PARAMETER_PROBLEM, "Port `%s' not valid\n", arg);
+
+	dash = strchr(arg, '-');
+	if (!dash) {
+		mr->range[0].min.tcp.port
+			= mr->range[0].max.tcp.port
+			= port;
+	} else {
+		int maxport;
+
+		maxport = atoi(dash + 1);
+		if (maxport == 0 || maxport > 65535)
+			exit_error(PARAMETER_PROBLEM,
+				   "Port `%s' not valid\n", dash+1);
+		if (maxport < port)
+			/* People are stupid.  Present reader excepted. */
+			exit_error(PARAMETER_PROBLEM,
+				   "Port range `%s' funky\n", arg);
+		mr->range[0].min.tcp.port = port;
+		mr->range[0].max.tcp.port = maxport;
+	}
+}
+
+/* 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)
+{
+	int portok;
+	struct ip_nat_multi_range *mr
+		= (struct ip_nat_multi_range *)(*target)->data;
+
+	if (entry->ip.proto == IPPROTO_TCP
+	    || entry->ip.proto == IPPROTO_UDP)
+		portok = 1;
+	else
+		portok = 0;
+
+	switch (c) {
+	case '1':
+		if (!portok)
+			exit_error(PARAMETER_PROBLEM,
+				   "Need TCP or UDP with port specification");
+
+		if (check_inverse(optarg, &invert))
+			exit_error(PARAMETER_PROBLEM,
+				   "Unexpected `!' after --to-ports");
+
+		parse_ports(optarg, mr);
+		return 1;
+
+	default:
+		return 0;
+	}
+}
+
+/* Final check; don't care. */
+static void final_check(unsigned int flags)
+{
+}
+
+/* Prints out the targinfo. */
+static void
+print(const struct ipt_ip *ip,
+      const struct ipt_entry_target *target,
+      int numeric)
+{
+	struct ip_nat_multi_range *mr
+		= (struct ip_nat_multi_range *)target->data;
+	struct ip_nat_range *r = &mr->range[0];
+
+	printf("MASQUERADE ");
+	if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
+		printf("%hu", r->min.tcp.port);
+		if (r->max.tcp.port != r->min.tcp.port)
+			printf("-%hu", r->max.tcp.port);
+		printf(" ");
+	}
+}
+
+/* Saves the union ipt_targinfo in parsable form to stdout. */
+static void
+save(const struct ipt_ip *ip, const struct ipt_entry_target *target)
+{
+	struct ip_nat_multi_range *mr
+		= (struct ip_nat_multi_range *)target->data;
+	struct ip_nat_range *r = &mr->range[0];
+
+	if (r->flags & IP_NAT_RANGE_PROTO_SPECIFIED) {
+		printf("%hu", r->min.tcp.port);
+		if (r->max.tcp.port != r->min.tcp.port)
+			printf("-%hu", r->max.tcp.port);
+		printf(" ");
+	}
+}
+
+struct iptables_target masq
+= { NULL,
+    "MASQUERADE",
+    NETFILTER_VERSION,
+    sizeof(struct ip_nat_multi_range),
+    &help,
+    &init,
+    &parse,
+    &final_check,
+    &print,
+    &save,
+    opts
+};
+
+void _init(void)
+{
+	register_target(&masq);
+}
-- 
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