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authorPatrick McHardy <kaber@trash.net>2006-12-02 22:09:41 -0800
committerDavid S. Miller <davem@davemloft.net>2006-12-02 22:09:41 -0800
commitf09943fefe6b702e40893d35b4f10fd1064037fe (patch)
treeb170d046ecf0642471bb3c55d8e1f316fe9e5ddc /net/ipv4
parent92703eee4ccde3c55ee067a89c373e8a51a8adf9 (diff)
[NETFILTER]: nf_conntrack/nf_nat: add PPTP helper port
Add nf_conntrack port of the PPtP conntrack/NAT helper. Since there seems to be no IPv6-capable PPtP implementation the helper only support IPv4. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/netfilter/Kconfig10
-rw-r--r--net/ipv4/netfilter/Makefile4
-rw-r--r--net/ipv4/netfilter/nf_nat_pptp.c315
-rw-r--r--net/ipv4/netfilter/nf_nat_proto_gre.c179
4 files changed, 508 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 4555f721dfc1..c3327ac024de 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -484,6 +484,10 @@ config IP_NF_NAT_SNMP_BASIC
# <expr> '&&' <expr> (6)
#
# (6) Returns the result of min(/expr/, /expr/).
+config NF_NAT_PROTO_GRE
+ tristate
+ depends on NF_NAT && NF_CT_PROTO_GRE
+
config IP_NF_NAT_FTP
tristate
depends on IP_NF_IPTABLES && IP_NF_CONNTRACK && IP_NF_NAT
@@ -528,6 +532,12 @@ config IP_NF_NAT_PPTP
default IP_NF_NAT if IP_NF_PPTP=y
default m if IP_NF_PPTP=m
+config NF_NAT_PPTP
+ tristate
+ depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
+ default NF_NAT && NF_CONNTRACK_PPTP
+ select NF_NAT_PROTO_GRE
+
config IP_NF_NAT_H323
tristate
depends on IP_NF_IPTABLES!=n && IP_NF_CONNTRACK!=n && IP_NF_NAT!=n
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 56733c370327..ef33ff2cdda9 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -54,6 +54,10 @@ obj-$(CONFIG_NF_NAT_AMANDA) += nf_nat_amanda.o
obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
+obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
+
+# NAT protocols (nf_nat)
+obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
# generic IP tables
obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o
diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
new file mode 100644
index 000000000000..0ae45b79a4eb
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_pptp.c
@@ -0,0 +1,315 @@
+/*
+ * nf_nat_pptp.c
+ *
+ * NAT support for PPTP (Point to Point Tunneling Protocol).
+ * PPTP is a a protocol for creating virtual private networks.
+ * It is a specification defined by Microsoft and some vendors
+ * working with Microsoft. PPTP is built on top of a modified
+ * version of the Internet Generic Routing Encapsulation Protocol.
+ * GRE is defined in RFC 1701 and RFC 1702. Documentation of
+ * PPTP can be found in RFC 2637
+ *
+ * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ *
+ * TODO: - NAT to a unique tuple, not to TCP source port
+ * (needs netfilter tuple reservation)
+ */
+
+#include <linux/module.h>
+#include <linux/tcp.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <linux/netfilter/nf_conntrack_proto_gre.h>
+#include <linux/netfilter/nf_conntrack_pptp.h>
+
+#define NF_NAT_PPTP_VERSION "3.0"
+
+#define REQ_CID(req, off) (*(__be16 *)((char *)(req) + (off)))
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Netfilter NAT helper module for PPTP");
+MODULE_ALIAS("ip_nat_pptp");
+
+#if 0
+extern const char *pptp_msg_name[];
+#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, \
+ __FUNCTION__, ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+static void pptp_nat_expected(struct nf_conn *ct,
+ struct nf_conntrack_expect *exp)
+{
+ struct nf_conn *master = ct->master;
+ struct nf_conntrack_expect *other_exp;
+ struct nf_conntrack_tuple t;
+ struct nf_ct_pptp_master *ct_pptp_info;
+ struct nf_nat_pptp *nat_pptp_info;
+ struct ip_nat_range range;
+
+ ct_pptp_info = &nfct_help(master)->help.ct_pptp_info;
+ nat_pptp_info = &nfct_nat(master)->help.nat_pptp_info;
+
+ /* And here goes the grand finale of corrosion... */
+ if (exp->dir == IP_CT_DIR_ORIGINAL) {
+ DEBUGP("we are PNS->PAC\n");
+ /* therefore, build tuple for PAC->PNS */
+ t.src.l3num = AF_INET;
+ t.src.u3.ip = master->tuplehash[!exp->dir].tuple.src.u3.ip;
+ t.src.u.gre.key = ct_pptp_info->pac_call_id;
+ t.dst.u3.ip = master->tuplehash[!exp->dir].tuple.dst.u3.ip;
+ t.dst.u.gre.key = ct_pptp_info->pns_call_id;
+ t.dst.protonum = IPPROTO_GRE;
+ } else {
+ DEBUGP("we are PAC->PNS\n");
+ /* build tuple for PNS->PAC */
+ t.src.l3num = AF_INET;
+ t.src.u3.ip = master->tuplehash[exp->dir].tuple.src.u3.ip;
+ t.src.u.gre.key = nat_pptp_info->pns_call_id;
+ t.dst.u3.ip = master->tuplehash[exp->dir].tuple.dst.u3.ip;
+ t.dst.u.gre.key = nat_pptp_info->pac_call_id;
+ t.dst.protonum = IPPROTO_GRE;
+ }
+
+ DEBUGP("trying to unexpect other dir: ");
+ NF_CT_DUMP_TUPLE(&t);
+ other_exp = nf_conntrack_expect_find_get(&t);
+ if (other_exp) {
+ nf_conntrack_unexpect_related(other_exp);
+ nf_conntrack_expect_put(other_exp);
+ DEBUGP("success\n");
+ } else {
+ DEBUGP("not found!\n");
+ }
+
+ /* This must be a fresh one. */
+ BUG_ON(ct->status & IPS_NAT_DONE_MASK);
+
+ /* Change src to where master sends to */
+ range.flags = IP_NAT_RANGE_MAP_IPS;
+ range.min_ip = range.max_ip
+ = ct->master->tuplehash[!exp->dir].tuple.dst.u3.ip;
+ if (exp->dir == IP_CT_DIR_ORIGINAL) {
+ range.flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+ range.min = range.max = exp->saved_proto;
+ }
+ /* hook doesn't matter, but it has to do source manip */
+ nf_nat_setup_info(ct, &range, NF_IP_POST_ROUTING);
+
+ /* For DST manip, map port here to where it's expected. */
+ range.flags = IP_NAT_RANGE_MAP_IPS;
+ range.min_ip = range.max_ip
+ = ct->master->tuplehash[!exp->dir].tuple.src.u3.ip;
+ if (exp->dir == IP_CT_DIR_REPLY) {
+ range.flags |= IP_NAT_RANGE_PROTO_SPECIFIED;
+ range.min = range.max = exp->saved_proto;
+ }
+ /* hook doesn't matter, but it has to do destination manip */
+ nf_nat_setup_info(ct, &range, NF_IP_PRE_ROUTING);
+}
+
+/* outbound packets == from PNS to PAC */
+static int
+pptp_outbound_pkt(struct sk_buff **pskb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq)
+
+{
+ struct nf_ct_pptp_master *ct_pptp_info;
+ struct nf_nat_pptp *nat_pptp_info;
+ u_int16_t msg;
+ __be16 new_callid;
+ unsigned int cid_off;
+
+ ct_pptp_info = &nfct_help(ct)->help.ct_pptp_info;
+ nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
+
+ new_callid = ct_pptp_info->pns_call_id;
+
+ switch (msg = ntohs(ctlh->messageType)) {
+ case PPTP_OUT_CALL_REQUEST:
+ cid_off = offsetof(union pptp_ctrl_union, ocreq.callID);
+ /* FIXME: ideally we would want to reserve a call ID
+ * here. current netfilter NAT core is not able to do
+ * this :( For now we use TCP source port. This breaks
+ * multiple calls within one control session */
+
+ /* save original call ID in nat_info */
+ nat_pptp_info->pns_call_id = ct_pptp_info->pns_call_id;
+
+ /* don't use tcph->source since we are at a DSTmanip
+ * hook (e.g. PREROUTING) and pkt is not mangled yet */
+ new_callid = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.tcp.port;
+
+ /* save new call ID in ct info */
+ ct_pptp_info->pns_call_id = new_callid;
+ break;
+ case PPTP_IN_CALL_REPLY:
+ cid_off = offsetof(union pptp_ctrl_union, icack.callID);
+ break;
+ case PPTP_CALL_CLEAR_REQUEST:
+ cid_off = offsetof(union pptp_ctrl_union, clrreq.callID);
+ break;
+ default:
+ DEBUGP("unknown outbound packet 0x%04x:%s\n", msg,
+ (msg <= PPTP_MSG_MAX)?
+ pptp_msg_name[msg]:pptp_msg_name[0]);
+ /* fall through */
+ case PPTP_SET_LINK_INFO:
+ /* only need to NAT in case PAC is behind NAT box */
+ case PPTP_START_SESSION_REQUEST:
+ case PPTP_START_SESSION_REPLY:
+ case PPTP_STOP_SESSION_REQUEST:
+ case PPTP_STOP_SESSION_REPLY:
+ case PPTP_ECHO_REQUEST:
+ case PPTP_ECHO_REPLY:
+ /* no need to alter packet */
+ return NF_ACCEPT;
+ }
+
+ /* only OUT_CALL_REQUEST, IN_CALL_REPLY, CALL_CLEAR_REQUEST pass
+ * down to here */
+ DEBUGP("altering call id from 0x%04x to 0x%04x\n",
+ ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_callid));
+
+ /* mangle packet */
+ if (nf_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+ cid_off + sizeof(struct pptp_pkt_hdr) +
+ sizeof(struct PptpControlHeader),
+ sizeof(new_callid), (char *)&new_callid,
+ sizeof(new_callid)) == 0)
+ return NF_DROP;
+ return NF_ACCEPT;
+}
+
+static void
+pptp_exp_gre(struct nf_conntrack_expect *expect_orig,
+ struct nf_conntrack_expect *expect_reply)
+{
+ struct nf_conn *ct = expect_orig->master;
+ struct nf_ct_pptp_master *ct_pptp_info;
+ struct nf_nat_pptp *nat_pptp_info;
+
+ ct_pptp_info = &nfct_help(ct)->help.ct_pptp_info;
+ nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
+
+ /* save original PAC call ID in nat_info */
+ nat_pptp_info->pac_call_id = ct_pptp_info->pac_call_id;
+
+ /* alter expectation for PNS->PAC direction */
+ expect_orig->saved_proto.gre.key = ct_pptp_info->pns_call_id;
+ expect_orig->tuple.src.u.gre.key = nat_pptp_info->pns_call_id;
+ expect_orig->tuple.dst.u.gre.key = ct_pptp_info->pac_call_id;
+ expect_orig->dir = IP_CT_DIR_ORIGINAL;
+
+ /* alter expectation for PAC->PNS direction */
+ expect_reply->saved_proto.gre.key = nat_pptp_info->pns_call_id;
+ expect_reply->tuple.src.u.gre.key = nat_pptp_info->pac_call_id;
+ expect_reply->tuple.dst.u.gre.key = ct_pptp_info->pns_call_id;
+ expect_reply->dir = IP_CT_DIR_REPLY;
+}
+
+/* inbound packets == from PAC to PNS */
+static int
+pptp_inbound_pkt(struct sk_buff **pskb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq)
+{
+ struct nf_nat_pptp *nat_pptp_info;
+ u_int16_t msg;
+ __be16 new_pcid;
+ unsigned int pcid_off;
+
+ nat_pptp_info = &nfct_nat(ct)->help.nat_pptp_info;
+ new_pcid = nat_pptp_info->pns_call_id;
+
+ switch (msg = ntohs(ctlh->messageType)) {
+ case PPTP_OUT_CALL_REPLY:
+ pcid_off = offsetof(union pptp_ctrl_union, ocack.peersCallID);
+ break;
+ case PPTP_IN_CALL_CONNECT:
+ pcid_off = offsetof(union pptp_ctrl_union, iccon.peersCallID);
+ break;
+ case PPTP_IN_CALL_REQUEST:
+ /* only need to nat in case PAC is behind NAT box */
+ return NF_ACCEPT;
+ case PPTP_WAN_ERROR_NOTIFY:
+ pcid_off = offsetof(union pptp_ctrl_union, wanerr.peersCallID);
+ break;
+ case PPTP_CALL_DISCONNECT_NOTIFY:
+ pcid_off = offsetof(union pptp_ctrl_union, disc.callID);
+ break;
+ case PPTP_SET_LINK_INFO:
+ pcid_off = offsetof(union pptp_ctrl_union, setlink.peersCallID);
+ break;
+ default:
+ DEBUGP("unknown inbound packet %s\n", (msg <= PPTP_MSG_MAX)?
+ pptp_msg_name[msg]:pptp_msg_name[0]);
+ /* fall through */
+ case PPTP_START_SESSION_REQUEST:
+ case PPTP_START_SESSION_REPLY:
+ case PPTP_STOP_SESSION_REQUEST:
+ case PPTP_STOP_SESSION_REPLY:
+ case PPTP_ECHO_REQUEST:
+ case PPTP_ECHO_REPLY:
+ /* no need to alter packet */
+ return NF_ACCEPT;
+ }
+
+ /* only OUT_CALL_REPLY, IN_CALL_CONNECT, IN_CALL_REQUEST,
+ * WAN_ERROR_NOTIFY, CALL_DISCONNECT_NOTIFY pass down here */
+
+ /* mangle packet */
+ DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",
+ ntohs(REQ_CID(pptpReq, pcid_off)), ntohs(new_pcid));
+
+ if (nf_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+ pcid_off + sizeof(struct pptp_pkt_hdr) +
+ sizeof(struct PptpControlHeader),
+ sizeof(new_pcid), (char *)&new_pcid,
+ sizeof(new_pcid)) == 0)
+ return NF_DROP;
+ return NF_ACCEPT;
+}
+
+static int __init nf_nat_helper_pptp_init(void)
+{
+ nf_nat_need_gre();
+
+ BUG_ON(rcu_dereference(nf_nat_pptp_hook_outbound));
+ rcu_assign_pointer(nf_nat_pptp_hook_outbound, pptp_outbound_pkt);
+
+ BUG_ON(rcu_dereference(nf_nat_pptp_hook_inbound));
+ rcu_assign_pointer(nf_nat_pptp_hook_inbound, pptp_inbound_pkt);
+
+ BUG_ON(rcu_dereference(nf_nat_pptp_hook_exp_gre));
+ rcu_assign_pointer(nf_nat_pptp_hook_exp_gre, pptp_exp_gre);
+
+ BUG_ON(rcu_dereference(nf_nat_pptp_hook_expectfn));
+ rcu_assign_pointer(nf_nat_pptp_hook_expectfn, pptp_nat_expected);
+ return 0;
+}
+
+static void __exit nf_nat_helper_pptp_fini(void)
+{
+ rcu_assign_pointer(nf_nat_pptp_hook_expectfn, NULL);
+ rcu_assign_pointer(nf_nat_pptp_hook_exp_gre, NULL);
+ rcu_assign_pointer(nf_nat_pptp_hook_inbound, NULL);
+ rcu_assign_pointer(nf_nat_pptp_hook_outbound, NULL);
+ synchronize_rcu();
+}
+
+module_init(nf_nat_helper_pptp_init);
+module_exit(nf_nat_helper_pptp_fini);
diff --git a/net/ipv4/netfilter/nf_nat_proto_gre.c b/net/ipv4/netfilter/nf_nat_proto_gre.c
new file mode 100644
index 000000000000..d3de579e09d2
--- /dev/null
+++ b/net/ipv4/netfilter/nf_nat_proto_gre.c
@@ -0,0 +1,179 @@
+/*
+ * nf_nat_proto_gre.c
+ *
+ * NAT protocol helper module for GRE.
+ *
+ * GRE is a generic encapsulation protocol, which is generally not very
+ * suited for NAT, as it has no protocol-specific part as port numbers.
+ *
+ * It has an optional key field, which may help us distinguishing two
+ * connections between the same two hosts.
+ *
+ * GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
+ *
+ * PPTP is built on top of a modified version of GRE, and has a mandatory
+ * field called "CallID", which serves us for the same purpose as the key
+ * field in plain GRE.
+ *
+ * Documentation about PPTP can be found in RFC 2637
+ *
+ * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+
+#include <net/netfilter/nf_nat.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_nat_protocol.h>
+#include <linux/netfilter/nf_conntrack_proto_gre.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Netfilter NAT protocol helper module for GRE");
+
+#if 0
+#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, \
+ __FUNCTION__, ## args)
+#else
+#define DEBUGP(x, args...)
+#endif
+
+/* is key in given range between min and max */
+static int
+gre_in_range(const struct nf_conntrack_tuple *tuple,
+ enum nf_nat_manip_type maniptype,
+ const union nf_conntrack_man_proto *min,
+ const union nf_conntrack_man_proto *max)
+{
+ __be16 key;
+
+ if (maniptype == IP_NAT_MANIP_SRC)
+ key = tuple->src.u.gre.key;
+ else
+ key = tuple->dst.u.gre.key;
+
+ return ntohs(key) >= ntohs(min->gre.key) &&
+ ntohs(key) <= ntohs(max->gre.key);
+}
+
+/* generate unique tuple ... */
+static int
+gre_unique_tuple(struct nf_conntrack_tuple *tuple,
+ const struct nf_nat_range *range,
+ enum nf_nat_manip_type maniptype,
+ const struct nf_conn *conntrack)
+{
+ static u_int16_t key;
+ __be16 *keyptr;
+ unsigned int min, i, range_size;
+
+ if (maniptype == IP_NAT_MANIP_SRC)
+ keyptr = &tuple->src.u.gre.key;
+ else
+ keyptr = &tuple->dst.u.gre.key;
+
+ if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) {
+ DEBUGP("%p: NATing GRE PPTP\n", conntrack);
+ min = 1;
+ range_size = 0xffff;
+ } else {
+ min = ntohs(range->min.gre.key);
+ range_size = ntohs(range->max.gre.key) - min + 1;
+ }
+
+ DEBUGP("min = %u, range_size = %u\n", min, range_size);
+
+ for (i = 0; i < range_size; i++, key++) {
+ *keyptr = htons(min + key % range_size);
+ if (!nf_nat_used_tuple(tuple, conntrack))
+ return 1;
+ }
+
+ DEBUGP("%p: no NAT mapping\n", conntrack);
+ return 0;
+}
+
+/* manipulate a GRE packet according to maniptype */
+static int
+gre_manip_pkt(struct sk_buff **pskb, unsigned int iphdroff,
+ const struct nf_conntrack_tuple *tuple,
+ enum nf_nat_manip_type maniptype)
+{
+ struct gre_hdr *greh;
+ struct gre_hdr_pptp *pgreh;
+ struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff);
+ unsigned int hdroff = iphdroff + iph->ihl * 4;
+
+ /* pgreh includes two optional 32bit fields which are not required
+ * to be there. That's where the magic '8' comes from */
+ if (!skb_make_writable(pskb, hdroff + sizeof(*pgreh) - 8))
+ return 0;
+
+ greh = (void *)(*pskb)->data + hdroff;
+ pgreh = (struct gre_hdr_pptp *)greh;
+
+ /* we only have destination manip of a packet, since 'source key'
+ * is not present in the packet itself */
+ if (maniptype != IP_NAT_MANIP_DST)
+ return 1;
+ switch (greh->version) {
+ case 0:
+ if (!greh->key) {
+ DEBUGP("can't nat GRE w/o key\n");
+ break;
+ }
+ if (greh->csum) {
+ /* FIXME: Never tested this code... */
+ nf_proto_csum_replace4(gre_csum(greh), *pskb,
+ *(gre_key(greh)),
+ tuple->dst.u.gre.key, 0);
+ }
+ *(gre_key(greh)) = tuple->dst.u.gre.key;
+ break;
+ case GRE_VERSION_PPTP:
+ DEBUGP("call_id -> 0x%04x\n", ntohs(tuple->dst.u.gre.key));
+ pgreh->call_id = tuple->dst.u.gre.key;
+ break;
+ default:
+ DEBUGP("can't nat unknown GRE version\n");
+ return 0;
+ }
+ return 1;
+}
+
+static struct nf_nat_protocol gre __read_mostly = {
+ .name = "GRE",
+ .protonum = IPPROTO_GRE,
+ .manip_pkt = gre_manip_pkt,
+ .in_range = gre_in_range,
+ .unique_tuple = gre_unique_tuple,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+ defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+ .range_to_nfattr = nf_nat_port_range_to_nfattr,
+ .nfattr_to_range = nf_nat_port_nfattr_to_range,
+#endif
+};
+
+int __init nf_nat_proto_gre_init(void)
+{
+ return nf_nat_protocol_register(&gre);
+}
+
+void __exit nf_nat_proto_gre_fini(void)
+{
+ nf_nat_protocol_unregister(&gre);
+}
+
+module_init(nf_nat_proto_gre_init);
+module_exit(nf_nat_proto_gre_fini);
+
+void nf_nat_need_gre(void)
+{
+ return;
+}
+EXPORT_SYMBOL_GPL(nf_nat_need_gre);