patch-2.3.99-pre2 linux/net/ipv4/netfilter/ip_nat_proto_udp.c

• Lines: 142
• Date: Fri Mar 17 10:56:20 2000
• Orig file: v2.3.99-pre1/linux/net/ipv4/netfilter/ip_nat_proto_udp.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre1/linux/net/ipv4/netfilter/ip_nat_proto_udp.c linux/net/ipv4/netfilter/ip_nat_proto_udp.c
@@ -0,0 +1,141 @@
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+#include <linux/if.h>
+
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_nat_protocol.h>
+
+static int
+udp_in_range(const struct ip_conntrack_tuple *tuple,
+	     enum ip_nat_manip_type maniptype,
+	     const union ip_conntrack_manip_proto *min,
+	     const union ip_conntrack_manip_proto *max)
+{
+	u_int16_t port;
+
+	if (maniptype == IP_NAT_MANIP_SRC)
+		port = tuple->src.u.udp.port;
+	else
+		port = tuple->dst.u.udp.port;
+
+	return ntohs(port) >= ntohs(min->udp.port)
+		&& ntohs(port) <= ntohs(max->udp.port);
+}
+
+static int
+udp_unique_tuple(struct ip_conntrack_tuple *tuple,
+		 const struct ip_nat_range *range,
+		 enum ip_nat_manip_type maniptype,
+		 const struct ip_conntrack *conntrack)
+{
+	static u_int16_t port = 0, *portptr;
+	unsigned int range_size, min, i;
+
+	if (maniptype == IP_NAT_MANIP_SRC)
+		portptr = &tuple->src.u.udp.port;
+	else
+		portptr = &tuple->dst.u.udp.port;
+
+	/* If no range specified... */
+	if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) {
+		/* If it's dst rewrite, can't change port */
+		if (maniptype == IP_NAT_MANIP_DST)
+			return 0;
+
+		if (ntohs(*portptr) < 1024) {
+			/* Loose convention: >> 512 is credential passing */
+			if (ntohs(*portptr)<512) {
+				min = 1;
+				range_size = 511 - min + 1;
+			} else {
+				min = 600;
+				range_size = 1023 - min + 1;
+			}
+		} else {
+			min = 1024;
+			range_size = 65535 - 1024 + 1;
+		}
+	} else {
+		min = ntohs(range->min.udp.port);
+		range_size = ntohs(range->max.udp.port) - min + 1;
+	}
+
+	for (i = 0; i < range_size; i++, port++) {
+		*portptr = htons(min + port % range_size);
+		if (!ip_nat_used_tuple(tuple, conntrack))
+			return 1;
+	}
+	return 0;
+}
+
+static void
+udp_manip_pkt(struct iphdr *iph, size_t len,
+	      const struct ip_conntrack_manip *manip,
+	      enum ip_nat_manip_type maniptype)
+{
+	struct udphdr *hdr = (struct udphdr *)((u_int32_t *)iph + iph->ihl);
+	u_int32_t oldip;
+	u_int16_t *portptr;
+
+	if (maniptype == IP_NAT_MANIP_SRC) {
+		/* Get rid of src ip and src pt */
+		oldip = iph->saddr;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst ip and dst pt */
+		oldip = iph->daddr;
+		portptr = &hdr->dest;
+	}
+	hdr->check = ip_nat_cheat_check(~oldip, manip->ip,
+					ip_nat_cheat_check(*portptr ^ 0xFFFF,
+							   manip->u.udp.port,
+							   hdr->check));
+	*portptr = manip->u.udp.port;
+}
+
+static unsigned int
+udp_print(char *buffer,
+	  const struct ip_conntrack_tuple *match,
+	  const struct ip_conntrack_tuple *mask)
+{
+	unsigned int len = 0;
+
+	if (mask->src.u.udp.port)
+		len += sprintf(buffer + len, "srcpt=%u ",
+			       ntohs(match->src.u.udp.port));
+
+
+	if (mask->dst.u.udp.port)
+		len += sprintf(buffer + len, "dstpt=%u ",
+			       ntohs(match->dst.u.udp.port));
+
+	return len;
+}
+
+static unsigned int
+udp_print_range(char *buffer, const struct ip_nat_range *range)
+{
+	if (range->min.udp.port != 0 || range->max.udp.port != 0xFFFF) {
+		if (range->min.udp.port == range->max.udp.port)
+			return sprintf(buffer, "port %u ",
+				       ntohs(range->min.udp.port));
+		else
+			return sprintf(buffer, "ports %u-%u ",
+				       ntohs(range->min.udp.port),
+				       ntohs(range->max.udp.port));
+	}
+	else return 0;
+}
+
+struct ip_nat_protocol ip_nat_protocol_udp
+= { { NULL, NULL }, "UDP", IPPROTO_UDP,
+    udp_manip_pkt,
+    udp_in_range,
+    udp_unique_tuple,
+    udp_print,
+    udp_print_range
+};