| /* |
| * DCCP NAT protocol helper |
| * |
| * Copyright (c) 2005, 2006. 2008 Patrick McHardy <kaber@trash.net> |
| * |
| * 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/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/skbuff.h> |
| #include <linux/ip.h> |
| #include <linux/dccp.h> |
| |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_nat.h> |
| #include <net/netfilter/nf_nat_protocol.h> |
| |
| static u_int16_t dccp_port_rover; |
| |
| static bool |
| dccp_unique_tuple(struct nf_conntrack_tuple *tuple, |
| const struct nf_nat_range *range, |
| enum nf_nat_manip_type maniptype, |
| const struct nf_conn *ct) |
| { |
| return nf_nat_proto_unique_tuple(tuple, range, maniptype, ct, |
| &dccp_port_rover); |
| } |
| |
| static bool |
| dccp_manip_pkt(struct sk_buff *skb, |
| unsigned int iphdroff, |
| const struct nf_conntrack_tuple *tuple, |
| enum nf_nat_manip_type maniptype) |
| { |
| const struct iphdr *iph = (const void *)(skb->data + iphdroff); |
| struct dccp_hdr *hdr; |
| unsigned int hdroff = iphdroff + iph->ihl * 4; |
| __be32 oldip, newip; |
| __be16 *portptr, oldport, newport; |
| int hdrsize = 8; /* DCCP connection tracking guarantees this much */ |
| |
| if (skb->len >= hdroff + sizeof(struct dccp_hdr)) |
| hdrsize = sizeof(struct dccp_hdr); |
| |
| if (!skb_make_writable(skb, hdroff + hdrsize)) |
| return false; |
| |
| iph = (struct iphdr *)(skb->data + iphdroff); |
| hdr = (struct dccp_hdr *)(skb->data + hdroff); |
| |
| if (maniptype == IP_NAT_MANIP_SRC) { |
| oldip = iph->saddr; |
| newip = tuple->src.u3.ip; |
| newport = tuple->src.u.dccp.port; |
| portptr = &hdr->dccph_sport; |
| } else { |
| oldip = iph->daddr; |
| newip = tuple->dst.u3.ip; |
| newport = tuple->dst.u.dccp.port; |
| portptr = &hdr->dccph_dport; |
| } |
| |
| oldport = *portptr; |
| *portptr = newport; |
| |
| if (hdrsize < sizeof(*hdr)) |
| return true; |
| |
| inet_proto_csum_replace4(&hdr->dccph_checksum, skb, oldip, newip, 1); |
| inet_proto_csum_replace2(&hdr->dccph_checksum, skb, oldport, newport, |
| 0); |
| return true; |
| } |
| |
| static const struct nf_nat_protocol nf_nat_protocol_dccp = { |
| .protonum = IPPROTO_DCCP, |
| .me = THIS_MODULE, |
| .manip_pkt = dccp_manip_pkt, |
| .in_range = nf_nat_proto_in_range, |
| .unique_tuple = dccp_unique_tuple, |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .range_to_nlattr = nf_nat_proto_range_to_nlattr, |
| .nlattr_to_range = nf_nat_proto_nlattr_to_range, |
| #endif |
| }; |
| |
| static int __init nf_nat_proto_dccp_init(void) |
| { |
| return nf_nat_protocol_register(&nf_nat_protocol_dccp); |
| } |
| |
| static void __exit nf_nat_proto_dccp_fini(void) |
| { |
| nf_nat_protocol_unregister(&nf_nat_protocol_dccp); |
| } |
| |
| module_init(nf_nat_proto_dccp_init); |
| module_exit(nf_nat_proto_dccp_fini); |
| |
| MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
| MODULE_DESCRIPTION("DCCP NAT protocol helper"); |
| MODULE_LICENSE("GPL"); |