blob: b1e627227b6e2670fb6ce9d151e8965a4c8731c3 [file] [log] [blame]
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <>
* 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/export.h>
#include <linux/init.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_l3proto.h>
#include <net/netfilter/nf_nat_l4proto.h>
static u16 udp_port_rover;
static void
udp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
static bool
udp_manip_pkt(struct sk_buff *skb,
const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
struct udphdr *hdr;
__be16 *portptr, newport;
if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
return false;
hdr = (struct udphdr *)(skb->data + hdroff);
if (maniptype == NF_NAT_MANIP_SRC) {
/* Get rid of src port */
newport = tuple->src.u.udp.port;
portptr = &hdr->source;
} else {
/* Get rid of dst port */
newport = tuple->dst.u.udp.port;
portptr = &hdr->dest;
if (hdr->check || skb->ip_summed == CHECKSUM_PARTIAL) {
l3proto->csum_update(skb, iphdroff, &hdr->check,
tuple, maniptype);
inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport,
if (!hdr->check)
hdr->check = CSUM_MANGLED_0;
*portptr = newport;
return true;
const struct nf_nat_l4proto nf_nat_l4proto_udp = {
.l4proto = IPPROTO_UDP,
.manip_pkt = udp_manip_pkt,
.in_range = nf_nat_l4proto_in_range,
.unique_tuple = udp_unique_tuple,
.nlattr_to_range = nf_nat_l4proto_nlattr_to_range,