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- /*
- * 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/dccp.h>
- #include <net/netfilter/nf_conntrack.h>
- #include <net/netfilter/nf_nat.h>
- #include <net/netfilter/nf_nat_l3proto.h>
- #include <net/netfilter/nf_nat_l4proto.h>
- static u_int16_t dccp_port_rover;
- static void
- dccp_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,
- &dccp_port_rover);
- }
- static bool
- dccp_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 dccp_hdr *hdr;
- __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;
- hdr = (struct dccp_hdr *)(skb->data + hdroff);
- if (maniptype == NF_NAT_MANIP_SRC) {
- newport = tuple->src.u.dccp.port;
- portptr = &hdr->dccph_sport;
- } else {
- newport = tuple->dst.u.dccp.port;
- portptr = &hdr->dccph_dport;
- }
- oldport = *portptr;
- *portptr = newport;
- if (hdrsize < sizeof(*hdr))
- return true;
- l3proto->csum_update(skb, iphdroff, &hdr->dccph_checksum,
- tuple, maniptype);
- inet_proto_csum_replace2(&hdr->dccph_checksum, skb, oldport, newport,
- false);
- return true;
- }
- static const struct nf_nat_l4proto nf_nat_l4proto_dccp = {
- .l4proto = IPPROTO_DCCP,
- .manip_pkt = dccp_manip_pkt,
- .in_range = nf_nat_l4proto_in_range,
- .unique_tuple = dccp_unique_tuple,
- #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
- .nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
- #endif
- };
- static int __init nf_nat_proto_dccp_init(void)
- {
- int err;
- err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
- if (err < 0)
- goto err1;
- err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
- if (err < 0)
- goto err2;
- return 0;
- err2:
- nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_dccp);
- err1:
- return err;
- }
- static void __exit nf_nat_proto_dccp_fini(void)
- {
- nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_dccp);
- nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_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");
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