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/sctp.h>
  11#include <net/sctp/checksum.h>
  12
  13#include <net/netfilter/nf_nat_l4proto.h>
  14
  15static u_int16_t nf_sctp_port_rover;
  16
  17static void
  18sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
  19                  struct nf_conntrack_tuple *tuple,
  20                  const struct nf_nat_range *range,
  21                  enum nf_nat_manip_type maniptype,
  22                  const struct nf_conn *ct)
  23{
  24        nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
  25                                    &nf_sctp_port_rover);
  26}
  27
  28static bool
  29sctp_manip_pkt(struct sk_buff *skb,
  30               const struct nf_nat_l3proto *l3proto,
  31               unsigned int iphdroff, unsigned int hdroff,
  32               const struct nf_conntrack_tuple *tuple,
  33               enum nf_nat_manip_type maniptype)
  34{
  35        sctp_sctphdr_t *hdr;
  36
  37        if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
  38                return false;
  39
  40        hdr = (struct sctphdr *)(skb->data + hdroff);
  41
  42        if (maniptype == NF_NAT_MANIP_SRC) {
  43                /* Get rid of src port */
  44                hdr->source = tuple->src.u.sctp.port;
  45        } else {
  46                /* Get rid of dst port */
  47                hdr->dest = tuple->dst.u.sctp.port;
  48        }
  49
  50        if (skb->ip_summed != CHECKSUM_PARTIAL) {
  51                hdr->checksum = sctp_compute_cksum(skb, hdroff);
  52                skb->ip_summed = CHECKSUM_NONE;
  53        }
  54
  55        return true;
  56}
  57
  58const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
  59        .l4proto                = IPPROTO_SCTP,
  60        .manip_pkt              = sctp_manip_pkt,
  61        .in_range               = nf_nat_l4proto_in_range,
  62        .unique_tuple           = sctp_unique_tuple,
  63#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
  64        .nlattr_to_range        = nf_nat_l4proto_nlattr_to_range,
  65#endif
  66};
  67