LXR linux/net/netfilter/nf_nat_proto

   1/*
   2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 */
   8
   9#include <linux/types.h>
  10#include <linux/init.h>
  11#include <linux/sctp.h>
  12#include <linux/module.h>
  13#include <net/sctp/checksum.h>
  14
  15#include <net/netfilter/nf_nat_l4proto.h>
  16
  17static u_int16_t nf_sctp_port_rover;
  18
  19static void
  20sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
  21                  struct nf_conntrack_tuple *tuple,
  22                  const struct nf_nat_range *range,
  23                  enum nf_nat_manip_type maniptype,
  24                  const struct nf_conn *ct)
  25{
  26        nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
  27                                    &nf_sctp_port_rover);
  28}
  29
  30static bool
  31sctp_manip_pkt(struct sk_buff *skb,
  32               const struct nf_nat_l3proto *l3proto,
  33               unsigned int iphdroff, unsigned int hdroff,
  34               const struct nf_conntrack_tuple *tuple,
  35               enum nf_nat_manip_type maniptype)
  36{
  37        sctp_sctphdr_t *hdr;
  38
  39        if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
  40                return false;
  41
  42        hdr = (struct sctphdr *)(skb->data + hdroff);
  43
  44        if (maniptype == NF_NAT_MANIP_SRC) {
  45                /* Get rid of src port */
  46                hdr->source = tuple->src.u.sctp.port;
  47        } else {
  48                /* Get rid of dst port */
  49                hdr->dest = tuple->dst.u.sctp.port;
  50        }
  51
  52        hdr->checksum = sctp_compute_cksum(skb, hdroff);
  53
  54        return true;
  55}
  56
  57static const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
  58        .l4proto                = IPPROTO_SCTP,
  59        .manip_pkt              = sctp_manip_pkt,
  60        .in_range               = nf_nat_l4proto_in_range,
  61        .unique_tuple           = sctp_unique_tuple,
  62#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
  63        .nlattr_to_range        = nf_nat_l4proto_nlattr_to_range,
  64#endif
  65};
  66
  67static int __init nf_nat_proto_sctp_init(void)
  68{
  69        int err;
  70
  71        err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
  72        if (err < 0)
  73                goto err1;
  74        err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
  75        if (err < 0)
  76                goto err2;
  77        return 0;
  78
  79err2:
  80        nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
  81err1:
  82        return err;
  83}
  84
  85static void __exit nf_nat_proto_sctp_exit(void)
  86{
  87        nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_sctp);
  88        nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp);
  89}
  90
  91module_init(nf_nat_proto_sctp_init);
  92module_exit(nf_nat_proto_sctp_exit);
  93
  94MODULE_LICENSE("GPL");
  95MODULE_DESCRIPTION("SCTP NAT protocol helper");
  96MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  97