diff options
Diffstat (limited to 'net/ipv4/netfilter/nf_nat_proto_dccp.c')
-rw-r--r-- | net/ipv4/netfilter/nf_nat_proto_dccp.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nf_nat_proto_dccp.c b/net/ipv4/netfilter/nf_nat_proto_dccp.c new file mode 100644 index 0000000..22485ce --- /dev/null +++ b/net/ipv4/netfilter/nf_nat_proto_dccp.c @@ -0,0 +1,108 @@ +/* + * 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"); |