[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>

2 files changed, 433 insertions, 0 deletions

diff --git a/include/linux/netfilter/nf_conntrack_pptp.h b/include/linux/netfilter/nf_conntrack_pptp.h
new file mode 100644
index 00000000000..fb049ec11ff
--- /dev/null
+++ b/include/linux/netfilter/nf_conntrack_pptp.h
@@ -0,0 +1,321 @@
+/* PPTP constants and structs */
+#ifndef _NF_CONNTRACK_PPTP_H
+#define _NF_CONNTRACK_PPTP_H
+
+/* state of the control session */
+enum pptp_ctrlsess_state {
+	PPTP_SESSION_NONE,			/* no session present */
+	PPTP_SESSION_ERROR,			/* some session error */
+	PPTP_SESSION_STOPREQ,			/* stop_sess request seen */
+	PPTP_SESSION_REQUESTED,			/* start_sess request seen */
+	PPTP_SESSION_CONFIRMED,			/* session established */
+};
+
+/* state of the call inside the control session */
+enum pptp_ctrlcall_state {
+	PPTP_CALL_NONE,
+	PPTP_CALL_ERROR,
+	PPTP_CALL_OUT_REQ,
+	PPTP_CALL_OUT_CONF,
+	PPTP_CALL_IN_REQ,
+	PPTP_CALL_IN_REP,
+	PPTP_CALL_IN_CONF,
+	PPTP_CALL_CLEAR_REQ,
+};
+
+/* conntrack private data */
+struct nf_ct_pptp_master {
+	enum pptp_ctrlsess_state sstate;	/* session state */
+	enum pptp_ctrlcall_state cstate;	/* call state */
+	__be16 pac_call_id;			/* call id of PAC */
+	__be16 pns_call_id;			/* call id of PNS */
+
+	/* in pre-2.6.11 this used to be per-expect. Now it is per-conntrack
+	 * and therefore imposes a fixed limit on the number of maps */
+	struct nf_ct_gre_keymap *keymap[IP_CT_DIR_MAX];
+};
+
+struct nf_nat_pptp {
+	__be16 pns_call_id;			/* NAT'ed PNS call id */
+	__be16 pac_call_id;			/* NAT'ed PAC call id */
+};
+
+#ifdef __KERNEL__
+
+#define PPTP_CONTROL_PORT	1723
+
+#define PPTP_PACKET_CONTROL	1
+#define PPTP_PACKET_MGMT	2
+
+#define PPTP_MAGIC_COOKIE	0x1a2b3c4d
+
+struct pptp_pkt_hdr {
+	__u16	packetLength;
+	__be16	packetType;
+	__be32	magicCookie;
+};
+
+/* PptpControlMessageType values */
+#define PPTP_START_SESSION_REQUEST	1
+#define PPTP_START_SESSION_REPLY	2
+#define PPTP_STOP_SESSION_REQUEST	3
+#define PPTP_STOP_SESSION_REPLY		4
+#define PPTP_ECHO_REQUEST		5
+#define PPTP_ECHO_REPLY			6
+#define PPTP_OUT_CALL_REQUEST		7
+#define PPTP_OUT_CALL_REPLY		8
+#define PPTP_IN_CALL_REQUEST		9
+#define PPTP_IN_CALL_REPLY		10
+#define PPTP_IN_CALL_CONNECT		11
+#define PPTP_CALL_CLEAR_REQUEST		12
+#define PPTP_CALL_DISCONNECT_NOTIFY	13
+#define PPTP_WAN_ERROR_NOTIFY		14
+#define PPTP_SET_LINK_INFO		15
+
+#define PPTP_MSG_MAX			15
+
+/* PptpGeneralError values */
+#define PPTP_ERROR_CODE_NONE		0
+#define PPTP_NOT_CONNECTED		1
+#define PPTP_BAD_FORMAT			2
+#define PPTP_BAD_VALUE			3
+#define PPTP_NO_RESOURCE		4
+#define PPTP_BAD_CALLID			5
+#define PPTP_REMOVE_DEVICE_ERROR	6
+
+struct PptpControlHeader {
+	__be16	messageType;
+	__u16	reserved;
+};
+
+/* FramingCapability Bitmap Values */
+#define PPTP_FRAME_CAP_ASYNC		0x1
+#define PPTP_FRAME_CAP_SYNC		0x2
+
+/* BearerCapability Bitmap Values */
+#define PPTP_BEARER_CAP_ANALOG		0x1
+#define PPTP_BEARER_CAP_DIGITAL		0x2
+
+struct PptpStartSessionRequest {
+	__be16	protocolVersion;
+	__u16	reserved1;
+	__be32	framingCapability;
+	__be32	bearerCapability;
+	__be16	maxChannels;
+	__be16	firmwareRevision;
+	__u8	hostName[64];
+	__u8	vendorString[64];
+};
+
+/* PptpStartSessionResultCode Values */
+#define PPTP_START_OK			1
+#define PPTP_START_GENERAL_ERROR	2
+#define PPTP_START_ALREADY_CONNECTED	3
+#define PPTP_START_NOT_AUTHORIZED	4
+#define PPTP_START_UNKNOWN_PROTOCOL	5
+
+struct PptpStartSessionReply {
+	__be16	protocolVersion;
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__be32	framingCapability;
+	__be32	bearerCapability;
+	__be16	maxChannels;
+	__be16	firmwareRevision;
+	__u8	hostName[64];
+	__u8	vendorString[64];
+};
+
+/* PptpStopReasons */
+#define PPTP_STOP_NONE			1
+#define PPTP_STOP_PROTOCOL		2
+#define PPTP_STOP_LOCAL_SHUTDOWN	3
+
+struct PptpStopSessionRequest {
+	__u8	reason;
+	__u8	reserved1;
+	__u16	reserved2;
+};
+
+/* PptpStopSessionResultCode */
+#define PPTP_STOP_OK			1
+#define PPTP_STOP_GENERAL_ERROR		2
+
+struct PptpStopSessionReply {
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__u16	reserved1;
+};
+
+struct PptpEchoRequest {
+	__be32 identNumber;
+};
+
+/* PptpEchoReplyResultCode */
+#define PPTP_ECHO_OK			1
+#define PPTP_ECHO_GENERAL_ERROR		2
+
+struct PptpEchoReply {
+	__be32	identNumber;
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__u16	reserved;
+};
+
+/* PptpFramingType */
+#define PPTP_ASYNC_FRAMING		1
+#define PPTP_SYNC_FRAMING		2
+#define PPTP_DONT_CARE_FRAMING		3
+
+/* PptpCallBearerType */
+#define PPTP_ANALOG_TYPE		1
+#define PPTP_DIGITAL_TYPE		2
+#define PPTP_DONT_CARE_BEARER_TYPE	3
+
+struct PptpOutCallRequest {
+	__be16	callID;
+	__be16	callSerialNumber;
+	__be32	minBPS;
+	__be32	maxBPS;
+	__be32	bearerType;
+	__be32	framingType;
+	__be16	packetWindow;
+	__be16	packetProcDelay;
+	__be16	phoneNumberLength;
+	__u16	reserved1;
+	__u8	phoneNumber[64];
+	__u8	subAddress[64];
+};
+
+/* PptpCallResultCode */
+#define PPTP_OUTCALL_CONNECT		1
+#define PPTP_OUTCALL_GENERAL_ERROR	2
+#define PPTP_OUTCALL_NO_CARRIER		3
+#define PPTP_OUTCALL_BUSY		4
+#define PPTP_OUTCALL_NO_DIAL_TONE	5
+#define PPTP_OUTCALL_TIMEOUT		6
+#define PPTP_OUTCALL_DONT_ACCEPT	7
+
+struct PptpOutCallReply {
+	__be16	callID;
+	__be16	peersCallID;
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__be16	causeCode;
+	__be32	connectSpeed;
+	__be16	packetWindow;
+	__be16	packetProcDelay;
+	__be32	physChannelID;
+};
+
+struct PptpInCallRequest {
+	__be16	callID;
+	__be16	callSerialNumber;
+	__be32	callBearerType;
+	__be32	physChannelID;
+	__be16	dialedNumberLength;
+	__be16	dialingNumberLength;
+	__u8	dialedNumber[64];
+	__u8	dialingNumber[64];
+	__u8	subAddress[64];
+};
+
+/* PptpInCallResultCode */
+#define PPTP_INCALL_ACCEPT		1
+#define PPTP_INCALL_GENERAL_ERROR	2
+#define PPTP_INCALL_DONT_ACCEPT		3
+
+struct PptpInCallReply {
+	__be16	callID;
+	__be16	peersCallID;
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__be16	packetWindow;
+	__be16	packetProcDelay;
+	__u16	reserved;
+};
+
+struct PptpInCallConnected {
+	__be16	peersCallID;
+	__u16	reserved;
+	__be32	connectSpeed;
+	__be16	packetWindow;
+	__be16	packetProcDelay;
+	__be32	callFramingType;
+};
+
+struct PptpClearCallRequest {
+	__be16	callID;
+	__u16	reserved;
+};
+
+struct PptpCallDisconnectNotify {
+	__be16	callID;
+	__u8	resultCode;
+	__u8	generalErrorCode;
+	__be16	causeCode;
+	__u16	reserved;
+	__u8	callStatistics[128];
+};
+
+struct PptpWanErrorNotify {
+	__be16	peersCallID;
+	__u16	reserved;
+	__be32	crcErrors;
+	__be32	framingErrors;
+	__be32	hardwareOverRuns;
+	__be32	bufferOverRuns;
+	__be32	timeoutErrors;
+	__be32	alignmentErrors;
+};
+
+struct PptpSetLinkInfo {
+	__be16	peersCallID;
+	__u16	reserved;
+	__be32	sendAccm;
+	__be32	recvAccm;
+};
+
+union pptp_ctrl_union {
+	struct PptpStartSessionRequest	sreq;
+	struct PptpStartSessionReply	srep;
+	struct PptpStopSessionRequest	streq;
+	struct PptpStopSessionReply	strep;
+	struct PptpOutCallRequest	ocreq;
+	struct PptpOutCallReply		ocack;
+	struct PptpInCallRequest	icreq;
+	struct PptpInCallReply		icack;
+	struct PptpInCallConnected	iccon;
+	struct PptpClearCallRequest	clrreq;
+	struct PptpCallDisconnectNotify disc;
+	struct PptpWanErrorNotify	wanerr;
+	struct PptpSetLinkInfo		setlink;
+};
+
+/* crap needed for nf_conntrack_compat.h */
+struct nf_conn;
+struct nf_conntrack_expect;
+enum ip_conntrack_info;
+
+extern int
+(*nf_nat_pptp_hook_outbound)(struct sk_buff **pskb,
+			     struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+			     struct PptpControlHeader *ctlh,
+			     union pptp_ctrl_union *pptpReq);
+
+extern int
+(*nf_nat_pptp_hook_inbound)(struct sk_buff **pskb,
+			    struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+			    struct PptpControlHeader *ctlh,
+			    union pptp_ctrl_union *pptpReq);
+
+extern void
+(*nf_nat_pptp_hook_exp_gre)(struct nf_conntrack_expect *exp_orig,
+			    struct nf_conntrack_expect *exp_reply);
+
+extern void
+(*nf_nat_pptp_hook_expectfn)(struct nf_conn *ct,
+			     struct nf_conntrack_expect *exp);
+
+#endif /* __KERNEL__ */
+#endif /* _NF_CONNTRACK_PPTP_H */
diff --git a/include/linux/netfilter/nf_conntrack_proto_gre.h b/include/linux/netfilter/nf_conntrack_proto_gre.h
new file mode 100644
index 00000000000..4e6bbce04ff
--- /dev/null
+++ b/include/linux/netfilter/nf_conntrack_proto_gre.h
@@ -0,0 +1,112 @@
+#ifndef _CONNTRACK_PROTO_GRE_H
+#define _CONNTRACK_PROTO_GRE_H
+#include <asm/byteorder.h>
+
+/* GRE PROTOCOL HEADER */
+
+/* GRE Version field */
+#define GRE_VERSION_1701	0x0
+#define GRE_VERSION_PPTP	0x1
+
+/* GRE Protocol field */
+#define GRE_PROTOCOL_PPTP	0x880B
+
+/* GRE Flags */
+#define GRE_FLAG_C		0x80
+#define GRE_FLAG_R		0x40
+#define GRE_FLAG_K		0x20
+#define GRE_FLAG_S		0x10
+#define GRE_FLAG_A		0x80
+
+#define GRE_IS_C(f)	((f)&GRE_FLAG_C)
+#define GRE_IS_R(f)	((f)&GRE_FLAG_R)
+#define GRE_IS_K(f)	((f)&GRE_FLAG_K)
+#define GRE_IS_S(f)	((f)&GRE_FLAG_S)
+#define GRE_IS_A(f)	((f)&GRE_FLAG_A)
+
+/* GRE is a mess: Four different standards */
+struct gre_hdr {
+#if defined(__LITTLE_ENDIAN_BITFIELD)
+	__u16	rec:3,
+		srr:1,
+		seq:1,
+		key:1,
+		routing:1,
+		csum:1,
+		version:3,
+		reserved:4,
+		ack:1;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+	__u16	csum:1,
+		routing:1,
+		key:1,
+		seq:1,
+		srr:1,
+		rec:3,
+		ack:1,
+		reserved:4,
+		version:3;
+#else
+#error "Adjust your <asm/byteorder.h> defines"
+#endif
+	__be16	protocol;
+};
+
+/* modified GRE header for PPTP */
+struct gre_hdr_pptp {
+	__u8   flags;		/* bitfield */
+	__u8   version;		/* should be GRE_VERSION_PPTP */
+	__be16 protocol;	/* should be GRE_PROTOCOL_PPTP */
+	__be16 payload_len;	/* size of ppp payload, not inc. gre header */
+	__be16 call_id;		/* peer's call_id for this session */
+	__be32 seq;		/* sequence number.  Present if S==1 */
+	__be32 ack;		/* seq number of highest packet recieved by */
+				/*  sender in this session */
+};
+
+struct nf_ct_gre {
+	unsigned int stream_timeout;
+	unsigned int timeout;
+};
+
+#ifdef __KERNEL__
+#include <net/netfilter/nf_conntrack_tuple.h>
+
+struct nf_conn;
+
+/* structure for original <-> reply keymap */
+struct nf_ct_gre_keymap {
+	struct list_head list;
+	struct nf_conntrack_tuple tuple;
+};
+
+/* add new tuple->key_reply pair to keymap */
+int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
+			 struct nf_conntrack_tuple *t);
+
+/* delete keymap entries */
+void nf_ct_gre_keymap_destroy(struct nf_conn *ct);
+
+/* get pointer to gre key, if present */
+static inline __be32 *gre_key(struct gre_hdr *greh)
+{
+	if (!greh->key)
+		return NULL;
+	if (greh->csum || greh->routing)
+		return (__be32 *)(greh+sizeof(*greh)+4);
+	return (__be32 *)(greh+sizeof(*greh));
+}
+
+/* get pointer ot gre csum, if present */
+static inline __sum16 *gre_csum(struct gre_hdr *greh)
+{
+	if (!greh->csum)
+		return NULL;
+	return (__sum16 *)(greh+sizeof(*greh));
+}
+
+extern void nf_ct_gre_keymap_flush(void);
+extern void nf_nat_need_gre(void);
+
+#endif /* __KERNEL__ */
+#endif /* _CONNTRACK_PROTO_GRE_H */