X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=net%2Fipv4%2Fnetfilter%2Fnf_nat_proto_udp.c;fp=net%2Fipv4%2Fnetfilter%2Fnf_nat_proto_udp.c;h=c00ab6e120fec694c63e45984b8ab7985ab3cc18;hb=76828883507a47dae78837ab5dec5a5b4513c667;hp=0000000000000000000000000000000000000000;hpb=64ba3f394c830ec48a1c31b53dcae312c56f1604;p=linux-2.6.git

diff --git a/net/ipv4/netfilter/nf_nat_proto_udp.c b/net/ipv4/netfilter/nf_nat_proto_udp.c
new file mode 100644
index 000000000..c00ab6e12
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_proto_udp.c
@@ -0,0 +1,137 @@
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/ip.h>
+#include <linux/udp.h>
+
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_core.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_nat_protocol.h>
+
+static int
+udp_in_range(const struct nf_conntrack_tuple *tuple,
+	     enum nf_nat_manip_type maniptype,
+	     const union nf_conntrack_man_proto *min,
+	     const union nf_conntrack_man_proto *max)
+{
+	__be16 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 nf_conntrack_tuple *tuple,
+		 const struct nf_nat_range *range,
+		 enum nf_nat_manip_type maniptype,
+		 const struct nf_conn *ct)
+{
+	static u_int16_t port;
+	__be16 *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 (!nf_nat_used_tuple(tuple, ct))
+			return 1;
+	}
+	return 0;
+}
+
+static int
+udp_manip_pkt(struct sk_buff **pskb,
+	      unsigned int iphdroff,
+	      const struct nf_conntrack_tuple *tuple,
+	      enum nf_nat_manip_type maniptype)
+{
+	struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff);
+	struct udphdr *hdr;
+	unsigned int hdroff = iphdroff + iph->ihl*4;
+	__be32 oldip, newip;
+	__be16 *portptr, newport;
+
+	if (!skb_make_writable(pskb, hdroff + sizeof(*hdr)))
+		return 0;
+
+	iph = (struct iphdr *)((*pskb)->data + iphdroff);
+	hdr = (struct udphdr *)((*pskb)->data + hdroff);
+
+	if (maniptype == IP_NAT_MANIP_SRC) {
+		/* Get rid of src ip and src pt */
+		oldip = iph->saddr;
+		newip = tuple->src.u3.ip;
+		newport = tuple->src.u.udp.port;
+		portptr = &hdr->source;
+	} else {
+		/* Get rid of dst ip and dst pt */
+		oldip = iph->daddr;
+		newip = tuple->dst.u3.ip;
+		newport = tuple->dst.u.udp.port;
+		portptr = &hdr->dest;
+	}
+	if (hdr->check || (*pskb)->ip_summed == CHECKSUM_PARTIAL) {
+		nf_proto_csum_replace4(&hdr->check, *pskb, oldip, newip, 1);
+		nf_proto_csum_replace2(&hdr->check, *pskb, *portptr, newport,
+				       0);
+		if (!hdr->check)
+			hdr->check = CSUM_MANGLED_0;
+	}
+	*portptr = newport;
+	return 1;
+}
+
+struct nf_nat_protocol nf_nat_protocol_udp = {
+	.name			= "UDP",
+	.protonum		= IPPROTO_UDP,
+	.me			= THIS_MODULE,
+	.manip_pkt		= udp_manip_pkt,
+	.in_range		= udp_in_range,
+	.unique_tuple		= udp_unique_tuple,
+#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
+	.range_to_nfattr	= nf_nat_port_range_to_nfattr,
+	.nfattr_to_range	= nf_nat_port_nfattr_to_range,
+#endif
+};