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authorHarald Welte <laforge@netfilter.org>2005-09-19 22:33:08 (GMT)
committerDavid S. Miller <davem@davemloft.net>2005-09-19 22:33:08 (GMT)
commit926b50f92a30090da2c1a8675de954c2d9b09732 (patch)
treec8dd1cadf83c8e5e1cdc666b5b5596c2ae5dc76a
parent772cb712b1373d335ef2874ea357ec681edc754b (diff)
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[NETFILTER]: Add new PPTP conntrack and NAT helper
This new "version 3" PPTP conntrack/nat helper is finally ready for mainline inclusion. Special thanks to lots of last-minute bugfixing by Patric McHardy. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netfilter_ipv4/ip_conntrack.h12
-rw-r--r--include/linux/netfilter_ipv4/ip_conntrack_pptp.h332
-rw-r--r--include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h114
-rw-r--r--include/linux/netfilter_ipv4/ip_conntrack_tuple.h7
-rw-r--r--include/linux/netfilter_ipv4/ip_nat_pptp.h11
-rw-r--r--net/ipv4/netfilter/Kconfig22
-rw-r--r--net/ipv4/netfilter/Makefile5
-rw-r--r--net/ipv4/netfilter/ip_conntrack_helper_pptp.c805
-rw-r--r--net/ipv4/netfilter/ip_conntrack_proto_gre.c327
-rw-r--r--net/ipv4/netfilter/ip_nat_helper_pptp.c401
-rw-r--r--net/ipv4/netfilter/ip_nat_proto_gre.c214
11 files changed, 2250 insertions, 0 deletions
diff --git a/include/linux/netfilter_ipv4/ip_conntrack.h b/include/linux/netfilter_ipv4/ip_conntrack.h
index 7e033e9..2df446c 100644
--- a/include/linux/netfilter_ipv4/ip_conntrack.h
+++ b/include/linux/netfilter_ipv4/ip_conntrack.h
@@ -133,11 +133,13 @@ enum ip_conntrack_expect_events {
#include <linux/netfilter_ipv4/ip_conntrack_tcp.h>
#include <linux/netfilter_ipv4/ip_conntrack_icmp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
#include <linux/netfilter_ipv4/ip_conntrack_sctp.h>
/* per conntrack: protocol private data */
union ip_conntrack_proto {
/* insert conntrack proto private data here */
+ struct ip_ct_gre gre;
struct ip_ct_sctp sctp;
struct ip_ct_tcp tcp;
struct ip_ct_icmp icmp;
@@ -148,6 +150,7 @@ union ip_conntrack_expect_proto {
};
/* Add protocol helper include file here */
+#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
#include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
#include <linux/netfilter_ipv4/ip_conntrack_irc.h>
@@ -155,12 +158,20 @@ union ip_conntrack_expect_proto {
/* per conntrack: application helper private data */
union ip_conntrack_help {
/* insert conntrack helper private data (master) here */
+ struct ip_ct_pptp_master ct_pptp_info;
struct ip_ct_ftp_master ct_ftp_info;
struct ip_ct_irc_master ct_irc_info;
};
#ifdef CONFIG_IP_NF_NAT_NEEDED
#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_pptp.h>
+
+/* per conntrack: nat application helper private data */
+union ip_conntrack_nat_help {
+ /* insert nat helper private data here */
+ struct ip_nat_pptp nat_pptp_info;
+};
#endif
#include <linux/types.h>
@@ -223,6 +234,7 @@ struct ip_conntrack
#ifdef CONFIG_IP_NF_NAT_NEEDED
struct {
struct ip_nat_info info;
+ union ip_conntrack_nat_help help;
#if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
int masq_index;
diff --git a/include/linux/netfilter_ipv4/ip_conntrack_pptp.h b/include/linux/netfilter_ipv4/ip_conntrack_pptp.h
new file mode 100644
index 0000000..389e385
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ip_conntrack_pptp.h
@@ -0,0 +1,332 @@
+/* PPTP constants and structs */
+#ifndef _CONNTRACK_PPTP_H
+#define _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 ip_ct_pptp_master {
+ enum pptp_ctrlsess_state sstate; /* session state */
+
+ /* everything below is going to be per-expectation in newnat,
+ * since there could be more than one call within one session */
+ enum pptp_ctrlcall_state cstate; /* call state */
+ u_int16_t pac_call_id; /* call id of PAC, host byte order */
+ u_int16_t pns_call_id; /* call id of PNS, host byte order */
+
+ /* 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 ip_ct_gre_keymap *keymap_orig, *keymap_reply;
+};
+
+/* conntrack_expect private member */
+struct ip_ct_pptp_expect {
+ enum pptp_ctrlcall_state cstate; /* call state */
+ u_int16_t pac_call_id; /* call id of PAC */
+ u_int16_t pns_call_id; /* call id of PNS */
+};
+
+
+#ifdef __KERNEL__
+
+#define IP_CONNTR_PPTP PPTP_CONTROL_PORT
+
+#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;
+ __u16 packetType;
+ __u32 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 {
+ __u16 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 {
+ __u16 protocolVersion;
+ __u8 reserved1;
+ __u8 reserved2;
+ __u32 framingCapability;
+ __u32 bearerCapability;
+ __u16 maxChannels;
+ __u16 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 {
+ __u16 protocolVersion;
+ __u8 resultCode;
+ __u8 generalErrorCode;
+ __u32 framingCapability;
+ __u32 bearerCapability;
+ __u16 maxChannels;
+ __u16 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;
+};
+
+/* PptpStopSessionResultCode */
+#define PPTP_STOP_OK 1
+#define PPTP_STOP_GENERAL_ERROR 2
+
+struct PptpStopSessionReply {
+ __u8 resultCode;
+ __u8 generalErrorCode;
+};
+
+struct PptpEchoRequest {
+ __u32 identNumber;
+};
+
+/* PptpEchoReplyResultCode */
+#define PPTP_ECHO_OK 1
+#define PPTP_ECHO_GENERAL_ERROR 2
+
+struct PptpEchoReply {
+ __u32 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 {
+ __u16 callID;
+ __u16 callSerialNumber;
+ __u32 minBPS;
+ __u32 maxBPS;
+ __u32 bearerType;
+ __u32 framingType;
+ __u16 packetWindow;
+ __u16 packetProcDelay;
+ __u16 reserved1;
+ __u16 phoneNumberLength;
+ __u16 reserved2;
+ __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 {
+ __u16 callID;
+ __u16 peersCallID;
+ __u8 resultCode;
+ __u8 generalErrorCode;
+ __u16 causeCode;
+ __u32 connectSpeed;
+ __u16 packetWindow;
+ __u16 packetProcDelay;
+ __u32 physChannelID;
+};
+
+struct PptpInCallRequest {
+ __u16 callID;
+ __u16 callSerialNumber;
+ __u32 callBearerType;
+ __u32 physChannelID;
+ __u16 dialedNumberLength;
+ __u16 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 {
+ __u16 callID;
+ __u16 peersCallID;
+ __u8 resultCode;
+ __u8 generalErrorCode;
+ __u16 packetWindow;
+ __u16 packetProcDelay;
+ __u16 reserved;
+};
+
+struct PptpInCallConnected {
+ __u16 peersCallID;
+ __u16 reserved;
+ __u32 connectSpeed;
+ __u16 packetWindow;
+ __u16 packetProcDelay;
+ __u32 callFramingType;
+};
+
+struct PptpClearCallRequest {
+ __u16 callID;
+ __u16 reserved;
+};
+
+struct PptpCallDisconnectNotify {
+ __u16 callID;
+ __u8 resultCode;
+ __u8 generalErrorCode;
+ __u16 causeCode;
+ __u16 reserved;
+ __u8 callStatistics[128];
+};
+
+struct PptpWanErrorNotify {
+ __u16 peersCallID;
+ __u16 reserved;
+ __u32 crcErrors;
+ __u32 framingErrors;
+ __u32 hardwareOverRuns;
+ __u32 bufferOverRuns;
+ __u32 timeoutErrors;
+ __u32 alignmentErrors;
+};
+
+struct PptpSetLinkInfo {
+ __u16 peersCallID;
+ __u16 reserved;
+ __u32 sendAccm;
+ __u32 recvAccm;
+};
+
+
+struct pptp_priv_data {
+ __u16 call_id;
+ __u16 mcall_id;
+ __u16 pcall_id;
+};
+
+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;
+};
+
+extern int
+(*ip_nat_pptp_hook_outbound)(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq);
+
+extern int
+(*ip_nat_pptp_hook_inbound)(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq);
+
+extern int
+(*ip_nat_pptp_hook_exp_gre)(struct ip_conntrack_expect *exp_orig,
+ struct ip_conntrack_expect *exp_reply);
+
+extern void
+(*ip_nat_pptp_hook_expectfn)(struct ip_conntrack *ct,
+ struct ip_conntrack_expect *exp);
+#endif /* __KERNEL__ */
+#endif /* _CONNTRACK_PPTP_H */
diff --git a/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h b/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h
new file mode 100644
index 0000000..8d090ef
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ip_conntrack_proto_gre.h
@@ -0,0 +1,114 @@
+#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
+ __u16 protocol;
+};
+
+/* modified GRE header for PPTP */
+struct gre_hdr_pptp {
+ __u8 flags; /* bitfield */
+ __u8 version; /* should be GRE_VERSION_PPTP */
+ __u16 protocol; /* should be GRE_PROTOCOL_PPTP */
+ __u16 payload_len; /* size of ppp payload, not inc. gre header */
+ __u16 call_id; /* peer's call_id for this session */
+ __u32 seq; /* sequence number. Present if S==1 */
+ __u32 ack; /* seq number of highest packet recieved by */
+ /* sender in this session */
+};
+
+
+/* this is part of ip_conntrack */
+struct ip_ct_gre {
+ unsigned int stream_timeout;
+ unsigned int timeout;
+};
+
+#ifdef __KERNEL__
+struct ip_conntrack_expect;
+struct ip_conntrack;
+
+/* structure for original <-> reply keymap */
+struct ip_ct_gre_keymap {
+ struct list_head list;
+
+ struct ip_conntrack_tuple tuple;
+};
+
+/* add new tuple->key_reply pair to keymap */
+int ip_ct_gre_keymap_add(struct ip_conntrack *ct,
+ struct ip_conntrack_tuple *t,
+ int reply);
+
+/* delete keymap entries */
+void ip_ct_gre_keymap_destroy(struct ip_conntrack *ct);
+
+
+/* get pointer to gre key, if present */
+static inline u_int32_t *gre_key(struct gre_hdr *greh)
+{
+ if (!greh->key)
+ return NULL;
+ if (greh->csum || greh->routing)
+ return (u_int32_t *) (greh+sizeof(*greh)+4);
+ return (u_int32_t *) (greh+sizeof(*greh));
+}
+
+/* get pointer ot gre csum, if present */
+static inline u_int16_t *gre_csum(struct gre_hdr *greh)
+{
+ if (!greh->csum)
+ return NULL;
+ return (u_int16_t *) (greh+sizeof(*greh));
+}
+
+#endif /* __KERNEL__ */
+
+#endif /* _CONNTRACK_PROTO_GRE_H */
diff --git a/include/linux/netfilter_ipv4/ip_conntrack_tuple.h b/include/linux/netfilter_ipv4/ip_conntrack_tuple.h
index c33f0b5..14dc0f7 100644
--- a/include/linux/netfilter_ipv4/ip_conntrack_tuple.h
+++ b/include/linux/netfilter_ipv4/ip_conntrack_tuple.h
@@ -28,6 +28,9 @@ union ip_conntrack_manip_proto
struct {
u_int16_t port;
} sctp;
+ struct {
+ u_int16_t key; /* key is 32bit, pptp only uses 16 */
+ } gre;
};
/* The manipulable part of the tuple. */
@@ -61,6 +64,10 @@ struct ip_conntrack_tuple
struct {
u_int16_t port;
} sctp;
+ struct {
+ u_int16_t key; /* key is 32bit,
+ * pptp only uses 16 */
+ } gre;
} u;
/* The protocol. */
diff --git a/include/linux/netfilter_ipv4/ip_nat_pptp.h b/include/linux/netfilter_ipv4/ip_nat_pptp.h
new file mode 100644
index 0000000..eaf66c2
--- /dev/null
+++ b/include/linux/netfilter_ipv4/ip_nat_pptp.h
@@ -0,0 +1,11 @@
+/* PPTP constants and structs */
+#ifndef _NAT_PPTP_H
+#define _NAT_PPTP_H
+
+/* conntrack private data */
+struct ip_nat_pptp {
+ u_int16_t pns_call_id; /* NAT'ed PNS call id */
+ u_int16_t pac_call_id; /* NAT'ed PAC call id */
+};
+
+#endif /* _NAT_PPTP_H */
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index e2162d2..3cf9b45 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -137,6 +137,22 @@ config IP_NF_AMANDA
To compile it as a module, choose M here. If unsure, say Y.
+config IP_NF_PPTP
+ tristate 'PPTP protocol support'
+ help
+ This module adds support for PPTP (Point to Point Tunnelling
+ Protocol, RFC2637) conncection tracking and NAT.
+
+ If you are running PPTP sessions over a stateful firewall or NAT
+ box, you may want to enable this feature.
+
+ Please note that not all PPTP modes of operation are supported yet.
+ For more info, read top of the file
+ net/ipv4/netfilter/ip_conntrack_pptp.c
+
+ If you want to compile it as a module, say M here and read
+ Documentation/modules.txt. If unsure, say `N'.
+
config IP_NF_QUEUE
tristate "IP Userspace queueing via NETLINK (OBSOLETE)"
help
@@ -621,6 +637,12 @@ config IP_NF_NAT_AMANDA
default IP_NF_NAT if IP_NF_AMANDA=y
default m if IP_NF_AMANDA=m
+config IP_NF_NAT_PPTP
+ tristate
+ depends on IP_NF_NAT!=n && IP_NF_PPTP!=n
+ default IP_NF_NAT if IP_NF_PPTP=y
+ default m if IP_NF_PPTP=m
+
# mangle + specific targets
config IP_NF_MANGLE
tristate "Packet mangling"
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 1ba0db7..3d45d3c 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -6,6 +6,9 @@
ip_conntrack-objs := ip_conntrack_standalone.o ip_conntrack_core.o ip_conntrack_proto_generic.o ip_conntrack_proto_tcp.o ip_conntrack_proto_udp.o ip_conntrack_proto_icmp.o
iptable_nat-objs := ip_nat_standalone.o ip_nat_rule.o ip_nat_core.o ip_nat_helper.o ip_nat_proto_unknown.o ip_nat_proto_tcp.o ip_nat_proto_udp.o ip_nat_proto_icmp.o
+ip_conntrack_pptp-objs := ip_conntrack_helper_pptp.o ip_conntrack_proto_gre.o
+ip_nat_pptp-objs := ip_nat_helper_pptp.o ip_nat_proto_gre.o
+
# connection tracking
obj-$(CONFIG_IP_NF_CONNTRACK) += ip_conntrack.o
@@ -17,6 +20,7 @@ obj-$(CONFIG_IP_NF_CONNTRACK_NETLINK) += ip_conntrack_netlink.o
obj-$(CONFIG_IP_NF_CT_PROTO_SCTP) += ip_conntrack_proto_sctp.o
# connection tracking helpers
+obj-$(CONFIG_IP_NF_PPTP) += ip_conntrack_pptp.o
obj-$(CONFIG_IP_NF_AMANDA) += ip_conntrack_amanda.o
obj-$(CONFIG_IP_NF_TFTP) += ip_conntrack_tftp.o
obj-$(CONFIG_IP_NF_FTP) += ip_conntrack_ftp.o
@@ -24,6 +28,7 @@ obj-$(CONFIG_IP_NF_IRC) += ip_conntrack_irc.o
obj-$(CONFIG_IP_NF_NETBIOS_NS) += ip_conntrack_netbios_ns.o
# NAT helpers
+obj-$(CONFIG_IP_NF_NAT_PPTP) += ip_nat_pptp.o
obj-$(CONFIG_IP_NF_NAT_AMANDA) += ip_nat_amanda.o
obj-$(CONFIG_IP_NF_NAT_TFTP) += ip_nat_tftp.o
obj-$(CONFIG_IP_NF_NAT_FTP) += ip_nat_ftp.o
diff --git a/net/ipv4/netfilter/ip_conntrack_helper_pptp.c b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
new file mode 100644
index 0000000..79db5b7
--- /dev/null
+++ b/net/ipv4/netfilter/ip_conntrack_helper_pptp.c
@@ -0,0 +1,805 @@
+/*
+ * ip_conntrack_pptp.c - Version 3.0
+ *
+ * Connection tracking 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/)
+ *
+ * Limitations:
+ * - We blindly assume that control connections are always
+ * established in PNS->PAC direction. This is a violation
+ * of RFFC2673
+ * - We can only support one single call within each session
+ *
+ * TODO:
+ * - testing of incoming PPTP calls
+ *
+ * Changes:
+ * 2002-02-05 - Version 1.3
+ * - Call ip_conntrack_unexpect_related() from
+ * pptp_destroy_siblings() to destroy expectations in case
+ * CALL_DISCONNECT_NOTIFY or tcp fin packet was seen
+ * (Philip Craig <philipc@snapgear.com>)
+ * - Add Version information at module loadtime
+ * 2002-02-10 - Version 1.6
+ * - move to C99 style initializers
+ * - remove second expectation if first arrives
+ * 2004-10-22 - Version 2.0
+ * - merge Mandrake's 2.6.x port with recent 2.6.x API changes
+ * - fix lots of linear skb assumptions from Mandrake's port
+ * 2005-06-10 - Version 2.1
+ * - use ip_conntrack_expect_free() instead of kfree() on the
+ * expect's (which are from the slab for quite some time)
+ * 2005-06-10 - Version 3.0
+ * - port helper to post-2.6.11 API changes,
+ * funded by Oxcoda NetBox Blue (http://www.netboxblue.com/)
+ * 2005-07-30 - Version 3.1
+ * - port helper to 2.6.13 API changes
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <net/checksum.h>
+#include <net/tcp.h>
+
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+#include <linux/netfilter_ipv4/ip_conntrack_core.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
+#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
+
+#define IP_CT_PPTP_VERSION "3.1"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Netfilter connection tracking helper module for PPTP");
+
+static DEFINE_SPINLOCK(ip_pptp_lock);
+
+int
+(*ip_nat_pptp_hook_outbound)(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq);
+
+int
+(*ip_nat_pptp_hook_inbound)(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq);
+
+int
+(*ip_nat_pptp_hook_exp_gre)(struct ip_conntrack_expect *expect_orig,
+ struct ip_conntrack_expect *expect_reply);
+
+void
+(*ip_nat_pptp_hook_expectfn)(struct ip_conntrack *ct,
+ struct ip_conntrack_expect *exp);
+
+#if 0
+/* PptpControlMessageType names */
+const char *pptp_msg_name[] = {
+ "UNKNOWN_MESSAGE",
+ "START_SESSION_REQUEST",
+ "START_SESSION_REPLY",
+ "STOP_SESSION_REQUEST",
+ "STOP_SESSION_REPLY",
+ "ECHO_REQUEST",
+ "ECHO_REPLY",
+ "OUT_CALL_REQUEST",
+ "OUT_CALL_REPLY",
+ "IN_CALL_REQUEST",
+ "IN_CALL_REPLY",
+ "IN_CALL_CONNECT",
+ "CALL_CLEAR_REQUEST",
+ "CALL_DISCONNECT_NOTIFY",
+ "WAN_ERROR_NOTIFY",
+ "SET_LINK_INFO"
+};
+EXPORT_SYMBOL(pptp_msg_name);
+#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
+#else
+#define DEBUGP(format, args...)
+#endif
+
+#define SECS *HZ
+#define MINS * 60 SECS
+#define HOURS * 60 MINS
+
+#define PPTP_GRE_TIMEOUT (10 MINS)
+#define PPTP_GRE_STREAM_TIMEOUT (5 HOURS)
+
+static void pptp_expectfn(struct ip_conntrack *ct,
+ struct ip_conntrack_expect *exp)
+{
+ DEBUGP("increasing timeouts\n");
+
+ /* increase timeout of GRE data channel conntrack entry */
+ ct->proto.gre.timeout = PPTP_GRE_TIMEOUT;
+ ct->proto.gre.stream_timeout = PPTP_GRE_STREAM_TIMEOUT;
+
+ /* Can you see how rusty this code is, compared with the pre-2.6.11
+ * one? That's what happened to my shiny newnat of 2002 ;( -HW */
+
+ if (!ip_nat_pptp_hook_expectfn) {
+ struct ip_conntrack_tuple inv_t;
+ struct ip_conntrack_expect *exp_other;
+
+ /* obviously this tuple inversion only works until you do NAT */
+ invert_tuplepr(&inv_t, &exp->tuple);
+ DEBUGP("trying to unexpect other dir: ");
+ DUMP_TUPLE(&inv_t);
+
+ exp_other = ip_conntrack_expect_find(&inv_t);
+ if (exp_other) {
+ /* delete other expectation. */
+ DEBUGP("found\n");
+ ip_conntrack_unexpect_related(exp_other);
+ ip_conntrack_expect_put(exp_other);
+ } else {
+ DEBUGP("not found\n");
+ }
+ } else {
+ /* we need more than simple inversion */
+ ip_nat_pptp_hook_expectfn(ct, exp);
+ }
+}
+
+static int destroy_sibling_or_exp(const struct ip_conntrack_tuple *t)
+{
+ struct ip_conntrack_tuple_hash *h;
+ struct ip_conntrack_expect *exp;
+
+ DEBUGP("trying to timeout ct or exp for tuple ");
+ DUMP_TUPLE(t);
+
+ h = ip_conntrack_find_get(t, NULL);
+ if (h) {
+ struct ip_conntrack *sibling = tuplehash_to_ctrack(h);
+ DEBUGP("setting timeout of conntrack %p to 0\n", sibling);
+ sibling->proto.gre.timeout = 0;
+ sibling->proto.gre.stream_timeout = 0;
+ /* refresh_acct will not modify counters if skb == NULL */
+ if (del_timer(&sibling->timeout))
+ sibling->timeout.function((unsigned long)sibling);
+ ip_conntrack_put(sibling);
+ return 1;
+ } else {
+ exp = ip_conntrack_expect_find(t);
+ if (exp) {
+ DEBUGP("unexpect_related of expect %p\n", exp);
+ ip_conntrack_unexpect_related(exp);
+ ip_conntrack_expect_put(exp);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+
+/* timeout GRE data connections */
+static void pptp_destroy_siblings(struct ip_conntrack *ct)
+{
+ struct ip_conntrack_tuple t;
+
+ /* Since ct->sibling_list has literally rusted away in 2.6.11,
+ * we now need another way to find out about our sibling
+ * contrack and expects... -HW */
+
+ /* try original (pns->pac) tuple */
+ memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
+ t.dst.protonum = IPPROTO_GRE;
+ t.src.u.gre.key = htons(ct->help.ct_pptp_info.pns_call_id);
+ t.dst.u.gre.key = htons(ct->help.ct_pptp_info.pac_call_id);
+
+ if (!destroy_sibling_or_exp(&t))
+ DEBUGP("failed to timeout original pns->pac ct/exp\n");
+
+ /* try reply (pac->pns) tuple */
+ memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
+ t.dst.protonum = IPPROTO_GRE;
+ t.src.u.gre.key = htons(ct->help.ct_pptp_info.pac_call_id);
+ t.dst.u.gre.key = htons(ct->help.ct_pptp_info.pns_call_id);
+
+ if (!destroy_sibling_or_exp(&t))
+ DEBUGP("failed to timeout reply pac->pns ct/exp\n");
+}
+
+/* expect GRE connections (PNS->PAC and PAC->PNS direction) */
+static inline int
+exp_gre(struct ip_conntrack *master,
+ u_int32_t seq,
+ u_int16_t callid,
+ u_int16_t peer_callid)
+{
+ struct ip_conntrack_tuple inv_tuple;
+ struct ip_conntrack_tuple exp_tuples[] = {
+ /* tuple in original direction, PNS->PAC */
+ { .src = { .ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip,
+ .u = { .gre = { .key = peer_callid } }
+ },
+ .dst = { .ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip,
+ .u = { .gre = { .key = callid } },
+ .protonum = IPPROTO_GRE
+ },
+ },
+ /* tuple in reply direction, PAC->PNS */
+ { .src = { .ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip,
+ .u = { .gre = { .key = callid } }
+ },
+ .dst = { .ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip,
+ .u = { .gre = { .key = peer_callid } },
+ .protonum = IPPROTO_GRE
+ },
+ }
+ };
+ struct ip_conntrack_expect *exp_orig, *exp_reply;
+ int ret = 1;
+
+ exp_orig = ip_conntrack_expect_alloc(master);
+ if (exp_orig == NULL)
+ goto out;
+
+ exp_reply = ip_conntrack_expect_alloc(master);
+ if (exp_reply == NULL)
+ goto out_put_orig;
+
+ memcpy(&exp_orig->tuple, &exp_tuples[0], sizeof(exp_orig->tuple));
+
+ exp_orig->mask.src.ip = 0xffffffff;
+ exp_orig->mask.src.u.all = 0;
+ exp_orig->mask.dst.u.all = 0;
+ exp_orig->mask.dst.u.gre.key = 0xffff;
+ exp_orig->mask.dst.ip = 0xffffffff;
+ exp_orig->mask.dst.protonum = 0xff;
+
+ exp_orig->master = master;
+ exp_orig->expectfn = pptp_expectfn;
+ exp_orig->flags = 0;
+
+ exp_orig->dir = IP_CT_DIR_ORIGINAL;
+
+ /* both expectations are identical apart from tuple */
+ memcpy(exp_reply, exp_orig, sizeof(*exp_reply));
+ memcpy(&exp_reply->tuple, &exp_tuples[1], sizeof(exp_reply->tuple));
+
+ exp_reply->dir = !exp_orig->dir;
+
+ if (ip_nat_pptp_hook_exp_gre)
+ ret = ip_nat_pptp_hook_exp_gre(exp_orig, exp_reply);
+ else {
+
+ DEBUGP("calling expect_related PNS->PAC");
+ DUMP_TUPLE(&exp_orig->tuple);
+
+ if (ip_conntrack_expect_related(exp_orig) != 0) {
+ DEBUGP("cannot expect_related()\n");
+ goto out_put_both;
+ }
+
+ DEBUGP("calling expect_related PAC->PNS");
+ DUMP_TUPLE(&exp_reply->tuple);
+
+ if (ip_conntrack_expect_related(exp_reply) != 0) {
+ DEBUGP("cannot expect_related()\n");
+ goto out_unexpect_orig;
+ }
+
+ /* Add GRE keymap entries */
+ if (ip_ct_gre_keymap_add(master, &exp_reply->tuple, 0) != 0) {
+ DEBUGP("cannot keymap_add() exp\n");
+ goto out_unexpect_both;
+ }
+
+ invert_tuplepr(&inv_tuple, &exp_reply->tuple);
+ if (ip_ct_gre_keymap_add(master, &inv_tuple, 1) != 0) {
+ ip_ct_gre_keymap_destroy(master);
+ DEBUGP("cannot keymap_add() exp_inv\n");
+ goto out_unexpect_both;
+ }
+ ret = 0;
+ }
+
+out_put_both:
+ ip_conntrack_expect_put(exp_reply);
+out_put_orig:
+ ip_conntrack_expect_put(exp_orig);
+out:
+ return ret;
+
+out_unexpect_both:
+ ip_conntrack_unexpect_related(exp_reply);
+out_unexpect_orig:
+ ip_conntrack_unexpect_related(exp_orig);
+ goto out_put_both;
+}
+
+static inline int
+pptp_inbound_pkt(struct sk_buff **pskb,
+ struct tcphdr *tcph,
+ unsigned int nexthdr_off,
+ unsigned int datalen,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ struct PptpControlHeader _ctlh, *ctlh;
+ unsigned int reqlen;
+ union pptp_ctrl_union _pptpReq, *pptpReq;
+ struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
+ u_int16_t msg, *cid, *pcid;
+ u_int32_t seq;
+
+ ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
+ if (!ctlh) {
+ DEBUGP("error during skb_header_pointer\n");
+ return NF_ACCEPT;
+ }
+ nexthdr_off += sizeof(_ctlh);
+ datalen -= sizeof(_ctlh);
+
+ reqlen = datalen;
+ if (reqlen > sizeof(*pptpReq))
+ reqlen = sizeof(*pptpReq);
+ pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
+ if (!pptpReq) {
+ DEBUGP("error during skb_header_pointer\n");
+ return NF_ACCEPT;
+ }
+
+ msg = ntohs(ctlh->messageType);
+ DEBUGP("inbound control message %s\n", pptp_msg_name[msg]);
+
+ switch (msg) {
+ case PPTP_START_SESSION_REPLY:
+ if (reqlen < sizeof(_pptpReq.srep)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server confirms new control session */
+ if (info->sstate < PPTP_SESSION_REQUESTED) {
+ DEBUGP("%s without START_SESS_REQUEST\n",
+ pptp_msg_name[msg]);
+ break;
+ }
+ if (pptpReq->srep.resultCode == PPTP_START_OK)
+ info->sstate = PPTP_SESSION_CONFIRMED;
+ else
+ info->sstate = PPTP_SESSION_ERROR;
+ break;
+
+ case PPTP_STOP_SESSION_REPLY:
+ if (reqlen < sizeof(_pptpReq.strep)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server confirms end of control session */
+ if (info->sstate > PPTP_SESSION_STOPREQ) {
+ DEBUGP("%s without STOP_SESS_REQUEST\n",
+ pptp_msg_name[msg]);
+ break;
+ }
+ if (pptpReq->strep.resultCode == PPTP_STOP_OK)
+ info->sstate = PPTP_SESSION_NONE;
+ else
+ info->sstate = PPTP_SESSION_ERROR;
+ break;
+
+ case PPTP_OUT_CALL_REPLY:
+ if (reqlen < sizeof(_pptpReq.ocack)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server accepted call, we now expect GRE frames */
+ if (info->sstate != PPTP_SESSION_CONFIRMED) {
+ DEBUGP("%s but no session\n", pptp_msg_name[msg]);
+ break;
+ }
+ if (info->cstate != PPTP_CALL_OUT_REQ &&
+ info->cstate != PPTP_CALL_OUT_CONF) {
+ DEBUGP("%s without OUTCALL_REQ\n", pptp_msg_name[msg]);
+ break;
+ }
+ if (pptpReq->ocack.resultCode != PPTP_OUTCALL_CONNECT) {
+ info->cstate = PPTP_CALL_NONE;
+ break;
+ }
+
+ cid = &pptpReq->ocack.callID;
+ pcid = &pptpReq->ocack.peersCallID;
+
+ info->pac_call_id = ntohs(*cid);
+
+ if (htons(info->pns_call_id) != *pcid) {
+ DEBUGP("%s for unknown callid %u\n",
+ pptp_msg_name[msg], ntohs(*pcid));
+ break;
+ }
+
+ DEBUGP("%s, CID=%X, PCID=%X\n", pptp_msg_name[msg],
+ ntohs(*cid), ntohs(*pcid));
+
+ info->cstate = PPTP_CALL_OUT_CONF;
+
+ seq = ntohl(tcph->seq) + sizeof(struct pptp_pkt_hdr)
+ + sizeof(struct PptpControlHeader)
+ + ((void *)pcid - (void *)pptpReq);
+
+ if (exp_gre(ct, seq, *cid, *pcid) != 0)
+ printk("ip_conntrack_pptp: error during exp_gre\n");
+ break;
+
+ case PPTP_IN_CALL_REQUEST:
+ if (reqlen < sizeof(_pptpReq.icack)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server tells us about incoming call request */
+ if (info->sstate != PPTP_SESSION_CONFIRMED) {
+ DEBUGP("%s but no session\n", pptp_msg_name[msg]);
+ break;
+ }
+ pcid = &pptpReq->icack.peersCallID;
+ DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(*pcid));
+ info->cstate = PPTP_CALL_IN_REQ;
+ info->pac_call_id = ntohs(*pcid);
+ break;
+
+ case PPTP_IN_CALL_CONNECT:
+ if (reqlen < sizeof(_pptpReq.iccon)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server tells us about incoming call established */
+ if (info->sstate != PPTP_SESSION_CONFIRMED) {
+ DEBUGP("%s but no session\n", pptp_msg_name[msg]);
+ break;
+ }
+ if (info->sstate != PPTP_CALL_IN_REP
+ && info->sstate != PPTP_CALL_IN_CONF) {
+ DEBUGP("%s but never sent IN_CALL_REPLY\n",
+ pptp_msg_name[msg]);
+ break;
+ }
+
+ pcid = &pptpReq->iccon.peersCallID;
+ cid = &info->pac_call_id;
+
+ if (info->pns_call_id != ntohs(*pcid)) {
+ DEBUGP("%s for unknown CallID %u\n",
+ pptp_msg_name[msg], ntohs(*cid));
+ break;
+ }
+
+ DEBUGP("%s, PCID=%X\n", pptp_msg_name[msg], ntohs(*pcid));
+ info->cstate = PPTP_CALL_IN_CONF;
+
+ /* we expect a GRE connection from PAC to PNS */
+ seq = ntohl(tcph->seq) + sizeof(struct pptp_pkt_hdr)
+ + sizeof(struct PptpControlHeader)
+ + ((void *)pcid - (void *)pptpReq);
+
+ if (exp_gre(ct, seq, *cid, *pcid) != 0)
+ printk("ip_conntrack_pptp: error during exp_gre\n");
+
+ break;
+
+ case PPTP_CALL_DISCONNECT_NOTIFY:
+ if (reqlen < sizeof(_pptpReq.disc)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* server confirms disconnect */
+ cid = &pptpReq->disc.callID;
+ DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(*cid));
+ info->cstate = PPTP_CALL_NONE;
+
+ /* untrack this call id, unexpect GRE packets */
+ pptp_destroy_siblings(ct);
+ break;
+
+ case PPTP_WAN_ERROR_NOTIFY:
+ break;
+
+ case PPTP_ECHO_REQUEST:
+ case PPTP_ECHO_REPLY:
+ /* I don't have to explain these ;) */
+ break;
+ default:
+ DEBUGP("invalid %s (TY=%d)\n", (msg <= PPTP_MSG_MAX)
+ ? pptp_msg_name[msg]:pptp_msg_name[0], msg);
+ break;
+ }
+
+
+ if (ip_nat_pptp_hook_inbound)
+ return ip_nat_pptp_hook_inbound(pskb, ct, ctinfo, ctlh,
+ pptpReq);
+
+ return NF_ACCEPT;
+
+}
+
+static inline int
+pptp_outbound_pkt(struct sk_buff **pskb,
+ struct tcphdr *tcph,
+ unsigned int nexthdr_off,
+ unsigned int datalen,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo)
+{
+ struct PptpControlHeader _ctlh, *ctlh;
+ unsigned int reqlen;
+ union pptp_ctrl_union _pptpReq, *pptpReq;
+ struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
+ u_int16_t msg, *cid, *pcid;
+
+ ctlh = skb_header_pointer(*pskb, nexthdr_off, sizeof(_ctlh), &_ctlh);
+ if (!ctlh)
+ return NF_ACCEPT;
+ nexthdr_off += sizeof(_ctlh);
+ datalen -= sizeof(_ctlh);
+
+ reqlen = datalen;
+ if (reqlen > sizeof(*pptpReq))
+ reqlen = sizeof(*pptpReq);
+ pptpReq = skb_header_pointer(*pskb, nexthdr_off, reqlen, &_pptpReq);
+ if (!pptpReq)
+ return NF_ACCEPT;
+
+ msg = ntohs(ctlh->messageType);
+ DEBUGP("outbound control message %s\n", pptp_msg_name[msg]);
+
+ switch (msg) {
+ case PPTP_START_SESSION_REQUEST:
+ /* client requests for new control session */
+ if (info->sstate != PPTP_SESSION_NONE) {
+ DEBUGP("%s but we already have one",
+ pptp_msg_name[msg]);
+ }
+ info->sstate = PPTP_SESSION_REQUESTED;
+ break;
+ case PPTP_STOP_SESSION_REQUEST:
+ /* client requests end of control session */
+ info->sstate = PPTP_SESSION_STOPREQ;
+ break;
+
+ case PPTP_OUT_CALL_REQUEST:
+ if (reqlen < sizeof(_pptpReq.ocreq)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ /* FIXME: break; */
+ }
+
+ /* client initiating connection to server */
+ if (info->sstate != PPTP_SESSION_CONFIRMED) {
+ DEBUGP("%s but no session\n",
+ pptp_msg_name[msg]);
+ break;
+ }
+ info->cstate = PPTP_CALL_OUT_REQ;
+ /* track PNS call id */
+ cid = &pptpReq->ocreq.callID;
+ DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(*cid));
+ info->pns_call_id = ntohs(*cid);
+ break;
+ case PPTP_IN_CALL_REPLY:
+ if (reqlen < sizeof(_pptpReq.icack)) {
+ DEBUGP("%s: short packet\n", pptp_msg_name[msg]);
+ break;
+ }
+
+ /* client answers incoming call */
+ if (info->cstate != PPTP_CALL_IN_REQ
+ && info->cstate != PPTP_CALL_IN_REP) {
+ DEBUGP("%s without incall_req\n",
+ pptp_msg_name[msg]);
+ break;
+ }
+ if (pptpReq->icack.resultCode != PPTP_INCALL_ACCEPT) {
+ info->cstate = PPTP_CALL_NONE;
+ break;
+ }
+ pcid = &pptpReq->icack.peersCallID;
+ if (info->pac_call_id != ntohs(*pcid)) {
+ DEBUGP("%s for unknown call %u\n",
+ pptp_msg_name[msg], ntohs(*pcid));
+ break;
+ }
+ DEBUGP("%s, CID=%X\n", pptp_msg_name[msg], ntohs(*pcid));
+ /* part two of the three-way handshake */
+ info->cstate = PPTP_CALL_IN_REP;
+ info->pns_call_id = ntohs(pptpReq->icack.callID);
+ break;
+
+ case PPTP_CALL_CLEAR_REQUEST:
+ /* client requests hangup of call */
+ if (info->sstate != PPTP_SESSION_CONFIRMED) {
+ DEBUGP("CLEAR_CALL but no session\n");
+ break;
+ }
+ /* FUTURE: iterate over all calls and check if
+ * call ID is valid. We don't do this without newnat,
+ * because we only know about last call */
+ info->cstate = PPTP_CALL_CLEAR_REQ;
+ break;
+ case PPTP_SET_LINK_INFO:
+ break;
+ case PPTP_ECHO_REQUEST:
+ case PPTP_ECHO_REPLY:
+ /* I don't have to explain these ;) */
+ break;
+ default:
+ DEBUGP("invalid %s (TY=%d)\n", (msg <= PPTP_MSG_MAX)?
+ pptp_msg_name[msg]:pptp_msg_name[0], msg);
+ /* unknown: no need to create GRE masq table entry */
+ break;
+ }
+
+ if (ip_nat_pptp_hook_outbound)
+ return ip_nat_pptp_hook_outbound(pskb, ct, ctinfo, ctlh,
+ pptpReq);
+
+ return NF_ACCEPT;
+}
+
+
+/* track caller id inside control connection, call expect_related */
+static int
+conntrack_pptp_help(struct sk_buff **pskb,
+ struct ip_conntrack *ct, enum ip_conntrack_info ctinfo)
+
+{
+ struct pptp_pkt_hdr _pptph, *pptph;
+ struct tcphdr _tcph, *tcph;
+ u_int32_t tcplen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4;
+ u_int32_t datalen;
+ int dir = CTINFO2DIR(ctinfo);
+ struct ip_ct_pptp_master *info = &ct->help.ct_pptp_info;
+ unsigned int nexthdr_off;
+
+ int oldsstate, oldcstate;
+ int ret;
+
+ /* don't do any tracking before tcp handshake complete */
+ if (ctinfo != IP_CT_ESTABLISHED
+ && ctinfo != IP_CT_ESTABLISHED+IP_CT_IS_REPLY) {
+ DEBUGP("ctinfo = %u, skipping\n", ctinfo);
+ return NF_ACCEPT;
+ }
+
+ nexthdr_off = (*pskb)->nh.iph->ihl*4;
+ tcph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_tcph), &_tcph);
+ BUG_ON(!tcph);
+ nexthdr_off += tcph->doff * 4;
+ datalen = tcplen - tcph->doff * 4;
+
+ if (tcph->fin || tcph->rst) {
+ DEBUGP("RST/FIN received, timeouting GRE\n");
+ /* can't do this after real newnat */
+ info->cstate = PPTP_CALL_NONE;
+
+ /* untrack this call id, unexpect GRE packets */
+ pptp_destroy_siblings(ct);
+ }
+
+ pptph = skb_header_pointer(*pskb, nexthdr_off, sizeof(_pptph), &_pptph);
+ if (!pptph) {
+ DEBUGP("no full PPTP header, can't track\n");
+ return NF_ACCEPT;
+ }
+ nexthdr_off += sizeof(_pptph);
+ datalen -= sizeof(_pptph);
+
+ /* if it's not a control message we can't do anything with it */
+ if (ntohs(pptph->packetType) != PPTP_PACKET_CONTROL ||
+ ntohl(pptph->magicCookie) != PPTP_MAGIC_COOKIE) {
+ DEBUGP("not a control packet\n");
+ return NF_ACCEPT;
+ }
+
+ oldsstate = info->sstate;
+ oldcstate = info->cstate;
+
+ spin_lock_bh(&ip_pptp_lock);
+
+ /* FIXME: We just blindly assume that the control connection is always
+ * established from PNS->PAC. However, RFC makes no guarantee */
+ if (dir == IP_CT_DIR_ORIGINAL)
+ /* client -> server (PNS -> PAC) */
+ ret = pptp_outbound_pkt(pskb, tcph, nexthdr_off, datalen, ct,
+ ctinfo);
+ else
+ /* server -> client (PAC -> PNS) */
+ ret = pptp_inbound_pkt(pskb, tcph, nexthdr_off, datalen, ct,
+ ctinfo);
+ DEBUGP("sstate: %d->%d, cstate: %d->%d\n",
+ oldsstate, info->sstate, oldcstate, info->cstate);
+ spin_unlock_bh(&ip_pptp_lock);
+
+ return ret;
+}
+
+/* control protocol helper */
+static struct ip_conntrack_helper pptp = {
+ .list = { NULL, NULL },
+ .name = "pptp",
+ .me = THIS_MODULE,
+ .max_expected = 2,
+ .timeout = 5 * 60,
+ .tuple = { .src = { .ip = 0,
+ .u = { .tcp = { .port =
+ __constant_htons(PPTP_CONTROL_PORT) } }
+ },
+ .dst = { .ip = 0,
+ .u = { .all = 0 },
+ .protonum = IPPROTO_TCP
+ }
+ },
+ .mask = { .src = { .ip = 0,
+ .u = { .tcp = { .port = 0xffff } }
+ },
+ .dst = { .ip = 0,
+ .u = { .all = 0 },
+ .protonum = 0xff
+ }
+ },
+ .help = conntrack_pptp_help
+};
+
+extern void __exit ip_ct_proto_gre_fini(void);
+extern int __init ip_ct_proto_gre_init(void);
+
+/* ip_conntrack_pptp initialization */
+static int __init init(void)
+{
+ int retcode;
+
+ retcode = ip_ct_proto_gre_init();
+ if (retcode < 0)
+ return retcode;
+
+ DEBUGP(" registering helper\n");
+ if ((retcode = ip_conntrack_helper_register(&pptp))) {
+ printk(KERN_ERR "Unable to register conntrack application "
+ "helper for pptp: %d\n", retcode);
+ ip_ct_proto_gre_fini();
+ return retcode;
+ }
+
+ printk("ip_conntrack_pptp version %s loaded\n", IP_CT_PPTP_VERSION);
+ return 0;
+}
+
+static void __exit fini(void)
+{
+ ip_conntrack_helper_unregister(&pptp);
+ ip_ct_proto_gre_fini();
+ printk("ip_conntrack_pptp version %s unloaded\n", IP_CT_PPTP_VERSION);
+}
+
+module_init(init);
+module_exit(fini);
+
+EXPORT_SYMBOL(ip_nat_pptp_hook_outbound);
+EXPORT_SYMBOL(ip_nat_pptp_hook_inbound);
+EXPORT_SYMBOL(ip_nat_pptp_hook_exp_gre);
+EXPORT_SYMBOL(ip_nat_pptp_hook_expectfn);
diff --git a/net/ipv4/netfilter/ip_conntrack_proto_gre.c b/net/ipv4/netfilter/ip_conntrack_proto_gre.c
new file mode 100644
index 0000000..de3cb9d
--- /dev/null
+++ b/net/ipv4/netfilter/ip_conntrack_proto_gre.c
@@ -0,0 +1,327 @@
+/*
+ * ip_conntrack_proto_gre.c - Version 3.0
+ *
+ * Connection tracking 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/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/netfilter.h>
+#include <linux/ip.h>
+#include <linux/in.h>
+#include <linux/list.h>
+
+static DEFINE_RWLOCK(ip_ct_gre_lock);
+#define ASSERT_READ_LOCK(x)
+#define ASSERT_WRITE_LOCK(x)
+
+#include <linux/netfilter_ipv4/listhelp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_core.h>
+
+#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
+#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("netfilter connection tracking protocol helper for GRE");
+
+/* shamelessly stolen from ip_conntrack_proto_udp.c */
+#define GRE_TIMEOUT (30*HZ)
+#define GRE_STREAM_TIMEOUT (180*HZ)
+
+#if 0
+#define DEBUGP(format, args...) printk(KERN_DEBUG "%s:%s: " format, __FILE__, __FUNCTION__, ## args)
+#define DUMP_TUPLE_GRE(x) printk("%u.%u.%u.%u:0x%x -> %u.%u.%u.%u:0x%x\n", \
+ NIPQUAD((x)->src.ip), ntohs((x)->src.u.gre.key), \
+ NIPQUAD((x)->dst.ip), ntohs((x)->dst.u.gre.key))
+#else
+#define DEBUGP(x, args...)
+#define DUMP_TUPLE_GRE(x)
+#endif
+
+/* GRE KEYMAP HANDLING FUNCTIONS */
+static LIST_HEAD(gre_keymap_list);
+
+static inline int gre_key_cmpfn(const struct ip_ct_gre_keymap *km,
+ const struct ip_conntrack_tuple *t)
+{
+ return ((km->tuple.src.ip == t->src.ip) &&
+ (km->tuple.dst.ip == t->dst.ip) &&
+ (km->tuple.dst.protonum == t->dst.protonum) &&
+ (km->tuple.dst.u.all == t->dst.u.all));
+}
+
+/* look up the source key for a given tuple */
+static u_int32_t gre_keymap_lookup(struct ip_conntrack_tuple *t)
+{
+ struct ip_ct_gre_keymap *km;
+ u_int32_t key = 0;
+
+ read_lock_bh(&ip_ct_gre_lock);
+ km = LIST_FIND(&gre_keymap_list, gre_key_cmpfn,
+ struct ip_ct_gre_keymap *, t);
+ if (km)
+ key = km->tuple.src.u.gre.key;
+ read_unlock_bh(&ip_ct_gre_lock);
+
+ DEBUGP("lookup src key 0x%x up key for ", key);
+ DUMP_TUPLE_GRE(t);
+
+ return key;
+}
+
+/* add a single keymap entry, associate with specified master ct */
+int
+ip_ct_gre_keymap_add(struct ip_conntrack *ct,
+ struct ip_conntrack_tuple *t, int reply)
+{
+ struct ip_ct_gre_keymap **exist_km, *km, *old;
+
+ if (!ct->helper || strcmp(ct->helper->name, "pptp")) {
+ DEBUGP("refusing to add GRE keymap to non-pptp session\n");
+ return -1;
+ }
+
+ if (!reply)
+ exist_km = &ct->help.ct_pptp_info.keymap_orig;
+ else
+ exist_km = &ct->help.ct_pptp_info.keymap_reply;
+
+ if (*exist_km) {
+ /* check whether it's a retransmission */
+ old = LIST_FIND(&gre_keymap_list, gre_key_cmpfn,
+ struct ip_ct_gre_keymap *, t);
+ if (old == *exist_km) {
+ DEBUGP("retransmission\n");
+ return 0;
+ }
+
+ DEBUGP("trying to override keymap_%s for ct %p\n",
+ reply? "reply":"orig", ct);
+ return -EEXIST;
+ }
+
+ km = kmalloc(sizeof(*km), GFP_ATOMIC);
+ if (!km)
+ return -ENOMEM;
+
+ memcpy(&km->tuple, t, sizeof(*t));
+ *exist_km = km;
+
+ DEBUGP("adding new entry %p: ", km);
+ DUMP_TUPLE_GRE(&km->tuple);
+
+ write_lock_bh(&ip_ct_gre_lock);
+ list_append(&gre_keymap_list, km);
+ write_unlock_bh(&ip_ct_gre_lock);
+
+ return 0;
+}
+
+/* destroy the keymap entries associated with specified master ct */
+void ip_ct_gre_keymap_destroy(struct ip_conntrack *ct)
+{
+ DEBUGP("entering for ct %p\n", ct);
+
+ if (!ct->helper || strcmp(ct->helper->name, "pptp")) {
+ DEBUGP("refusing to destroy GRE keymap to non-pptp session\n");
+ return;
+ }
+
+ write_lock_bh(&ip_ct_gre_lock);
+ if (ct->help.ct_pptp_info.keymap_orig) {
+ DEBUGP("removing %p from list\n",
+ ct->help.ct_pptp_info.keymap_orig);
+ list_del(&ct->help.ct_pptp_info.keymap_orig->list);
+ kfree(ct->help.ct_pptp_info.keymap_orig);
+ ct->help.ct_pptp_info.keymap_orig = NULL;
+ }
+ if (ct->help.ct_pptp_info.keymap_reply) {
+ DEBUGP("removing %p from list\n",
+ ct->help.ct_pptp_info.keymap_reply);
+ list_del(&ct->help.ct_pptp_info.keymap_reply->list);
+ kfree(ct->help.ct_pptp_info.keymap_reply);
+ ct->help.ct_pptp_info.keymap_reply = NULL;
+ }
+ write_unlock_bh(&ip_ct_gre_lock);
+}
+
+
+/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
+
+/* invert gre part of tuple */
+static int gre_invert_tuple(struct ip_conntrack_tuple *tuple,
+ const struct ip_conntrack_tuple *orig)
+{
+ tuple->dst.u.gre.key = orig->src.u.gre.key;
+ tuple->src.u.gre.key = orig->dst.u.gre.key;
+
+ return 1;
+}
+
+/* gre hdr info to tuple */
+static int gre_pkt_to_tuple(const struct sk_buff *skb,
+ unsigned int dataoff,
+ struct ip_conntrack_tuple *tuple)
+{
+ struct gre_hdr_pptp _pgrehdr, *pgrehdr;
+ u_int32_t srckey;
+ struct gre_hdr _grehdr, *grehdr;
+
+ /* first only delinearize old RFC1701 GRE header */
+ grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
+ if (!grehdr || grehdr->version != GRE_VERSION_PPTP) {
+ /* try to behave like "ip_conntrack_proto_generic" */
+ tuple->src.u.all = 0;
+ tuple->dst.u.all = 0;
+ return 1;
+ }
+
+ /* PPTP header is variable length, only need up to the call_id field */
+ pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
+ if (!pgrehdr)
+ return 1;
+
+ if (ntohs(grehdr->protocol) != GRE_PROTOCOL_PPTP) {
+ DEBUGP("GRE_VERSION_PPTP but unknown proto\n");
+ return 0;
+ }
+
+ tuple->dst.u.gre.key = pgrehdr->call_id;
+ srckey = gre_keymap_lookup(tuple);
+ tuple->src.u.gre.key = srckey;
+
+ return 1;
+}
+
+/* print gre part of tuple */
+static int gre_print_tuple(struct seq_file *s,
+ const struct ip_conntrack_tuple *tuple)
+{
+ return seq_printf(s, "srckey=0x%x dstkey=0x%x ",
+ ntohs(tuple->src.u.gre.key),
+ ntohs(tuple->dst.u.gre.key));
+}
+
+/* print private data for conntrack */
+static int gre_print_conntrack(struct seq_file *s,
+ const struct ip_conntrack *ct)
+{
+ return seq_printf(s, "timeout=%u, stream_timeout=%u ",
+ (ct->proto.gre.timeout / HZ),
+ (ct->proto.gre.stream_timeout / HZ));
+}
+
+/* Returns verdict for packet, and may modify conntrack */
+static int gre_packet(struct ip_conntrack *ct,
+ const struct sk_buff *skb,
+ enum ip_conntrack_info conntrackinfo)
+{
+ /* If we've seen traffic both ways, this is a GRE connection.
+ * Extend timeout. */
+ if (ct->status & IPS_SEEN_REPLY) {
+ ip_ct_refresh_acct(ct, conntrackinfo, skb,
+ ct->proto.gre.stream_timeout);
+ /* Also, more likely to be important, and not a probe. */
+ set_bit(IPS_ASSURED_BIT, &ct->status);
+ } else
+ ip_ct_refresh_acct(ct, conntrackinfo, skb,
+ ct->proto.gre.timeout);
+
+ return NF_ACCEPT;
+}
+
+/* Called when a new connection for this protocol found. */
+static int gre_new(struct ip_conntrack *ct,
+ const struct sk_buff *skb)
+{
+ DEBUGP(": ");
+ DUMP_TUPLE_GRE(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
+
+ /* initialize to sane value. Ideally a conntrack helper
+ * (e.g. in case of pptp) is increasing them */
+ ct->proto.gre.stream_timeout = GRE_STREAM_TIMEOUT;
+ ct->proto.gre.timeout = GRE_TIMEOUT;
+
+ return 1;
+}
+
+/* Called when a conntrack entry has already been removed from the hashes
+ * and is about to be deleted from memory */
+static void gre_destroy(struct ip_conntrack *ct)
+{
+ struct ip_conntrack *master = ct->master;
+ DEBUGP(" entering\n");
+
+ if (!master)
+ DEBUGP("no master !?!\n");
+ else
+ ip_ct_gre_keymap_destroy(master);
+}
+
+/* protocol helper struct */
+static struct ip_conntrack_protocol gre = {
+ .proto = IPPROTO_GRE,
+ .name = "gre",
+ .pkt_to_tuple = gre_pkt_to_tuple,
+ .invert_tuple = gre_invert_tuple,
+ .print_tuple = gre_print_tuple,
+ .print_conntrack = gre_print_conntrack,
+ .packet = gre_packet,
+ .new = gre_new,
+ .destroy = gre_destroy,
+ .me = THIS_MODULE,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+ defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+ .tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
+ .nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
+#endif
+};
+
+/* ip_conntrack_proto_gre initialization */
+int __init ip_ct_proto_gre_init(void)
+{
+ return ip_conntrack_protocol_register(&gre);
+}
+
+void __exit ip_ct_proto_gre_fini(void)
+{
+ struct list_head *pos, *n;
+
+ /* delete all keymap entries */
+ write_lock_bh(&ip_ct_gre_lock);
+ list_for_each_safe(pos, n, &gre_keymap_list) {
+ DEBUGP("deleting keymap %p at module unload time\n", pos);
+ list_del(pos);
+ kfree(pos);
+ }
+ write_unlock_bh(&ip_ct_gre_lock);
+
+ ip_conntrack_protocol_unregister(&gre);
+}
+
+EXPORT_SYMBOL(ip_ct_gre_keymap_add);
+EXPORT_SYMBOL(ip_ct_gre_keymap_destroy);
diff --git a/net/ipv4/netfilter/ip_nat_helper_pptp.c b/net/ipv4/netfilter/ip_nat_helper_pptp.c
new file mode 100644
index 0000000..3cdd068
--- /dev/null
+++ b/net/ipv4/netfilter/ip_nat_helper_pptp.c
@@ -0,0 +1,401 @@
+/*
+ * ip_nat_pptp.c - Version 3.0
+ *
+ * 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)
+ *
+ * Changes:
+ * 2002-02-10 - Version 1.3
+ * - Use ip_nat_mangle_tcp_packet() because of cloned skb's
+ * in local connections (Philip Craig <philipc@snapgear.com>)
+ * - add checks for magicCookie and pptp version
+ * - make argument list of pptp_{out,in}bound_packet() shorter
+ * - move to C99 style initializers
+ * - print version number at module loadtime
+ * 2003-09-22 - Version 1.5
+ * - use SNATed tcp sourceport as callid, since we get called before
+ * TCP header is mangled (Philip Craig <philipc@snapgear.com>)
+ * 2004-10-22 - Version 2.0
+ * - kernel 2.6.x version
+ * 2005-06-10 - Version 3.0
+ * - kernel >= 2.6.11 version,
+ * funded by Oxcoda NetBox Blue (http://www.netboxblue.com/)
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/tcp.h>
+#include <net/tcp.h>
+
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_nat_helper.h>
+#include <linux/netfilter_ipv4/ip_nat_pptp.h>
+#include <linux/netfilter_ipv4/ip_conntrack_core.h>
+#include <linux/netfilter_ipv4/ip_conntrack_helper.h>
+#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
+#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
+
+#define IP_NAT_PPTP_VERSION "3.0"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
+MODULE_DESCRIPTION("Netfilter NAT helper module for 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 ip_conntrack *ct,
+ struct ip_conntrack_expect *exp)
+{
+ struct ip_conntrack *master = ct->master;
+ struct ip_conntrack_expect *other_exp;
+ struct ip_conntrack_tuple t;
+ struct ip_ct_pptp_master *ct_pptp_info;
+ struct ip_nat_pptp *nat_pptp_info;
+
+ ct_pptp_info = &master->help.ct_pptp_info;
+ nat_pptp_info = &master->nat.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.ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip;
+ t.src.u.gre.key = htons(master->help.ct_pptp_info.pac_call_id);
+ t.dst.ip = master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip;
+ t.dst.u.gre.key = htons(master->help.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.ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip;
+ t.src.u.gre.key =
+ htons(master->nat.help.nat_pptp_info.pns_call_id);
+ t.dst.ip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip;
+ t.dst.u.gre.key =
+ htons(master->nat.help.nat_pptp_info.pac_call_id);
+ t.dst.protonum = IPPROTO_GRE;
+ }
+
+ DEBUGP("trying to unexpect other dir: ");
+ DUMP_TUPLE(&t);
+ other_exp = ip_conntrack_expect_find(&t);
+ if (other_exp) {
+ ip_conntrack_unexpect_related(other_exp);
+ ip_conntrack_expect_put(other_exp);
+ DEBUGP("success\n");
+ } else {
+ DEBUGP("not found!\n");
+ }
+
+ ip_nat_follow_master(ct, exp);
+}
+
+/* outbound packets == from PNS to PAC */
+static int
+pptp_outbound_pkt(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq)
+
+{
+ struct ip_ct_pptp_master *ct_pptp_info = &ct->help.ct_pptp_info;
+ struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
+
+ u_int16_t msg, *cid = NULL, new_callid;
+
+ new_callid = htons(ct_pptp_info->pns_call_id);
+
+ switch (msg = ntohs(ctlh->messageType)) {
+ case PPTP_OUT_CALL_REQUEST:
+ cid = &pptpReq->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 = ntohs(new_callid);
+ break;
+ case PPTP_IN_CALL_REPLY:
+ cid = &pptpReq->icreq.callID;
+ break;
+ case PPTP_CALL_CLEAR_REQUEST:
+ cid = &pptpReq->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 */
+
+ IP_NF_ASSERT(cid);
+
+ DEBUGP("altering call id from 0x%04x to 0x%04x\n",
+ ntohs(*cid), ntohs(new_callid));
+
+ /* mangle packet */
+ if (ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+ (void *)cid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)),
+ sizeof(new_callid),
+ (char *)&new_callid,
+ sizeof(new_callid)) == 0)
+ return NF_DROP;
+
+ return NF_ACCEPT;
+}
+
+static int
+pptp_exp_gre(struct ip_conntrack_expect *expect_orig,
+ struct ip_conntrack_expect *expect_reply)
+{
+ struct ip_ct_pptp_master *ct_pptp_info =
+ &expect_orig->master->help.ct_pptp_info;
+ struct ip_nat_pptp *nat_pptp_info =
+ &expect_orig->master->nat.help.nat_pptp_info;
+
+ struct ip_conntrack *ct = expect_orig->master;
+
+ struct ip_conntrack_tuple inv_t;
+ struct ip_conntrack_tuple *orig_t, *reply_t;
+
+ /* save original PAC call ID in nat_info */
+ nat_pptp_info->pac_call_id = ct_pptp_info->pac_call_id;
+
+ /* alter expectation */
+ orig_t = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
+ reply_t = &ct->tuplehash[IP_CT_DIR_REPLY].tuple;
+
+ /* alter expectation for PNS->PAC direction */
+ invert_tuplepr(&inv_t, &expect_orig->tuple);
+ expect_orig->saved_proto.gre.key = htons(nat_pptp_info->pac_call_id);
+ expect_orig->tuple.src.u.gre.key = htons(nat_pptp_info->pns_call_id);
+ expect_orig->tuple.dst.u.gre.key = htons(ct_pptp_info->pac_call_id);
+ inv_t.src.ip = reply_t->src.ip;
+ inv_t.dst.ip = reply_t->dst.ip;
+ inv_t.src.u.gre.key = htons(nat_pptp_info->pac_call_id);
+ inv_t.dst.u.gre.key = htons(ct_pptp_info->pns_call_id);
+
+ if (!ip_conntrack_expect_related(expect_orig)) {
+ DEBUGP("successfully registered expect\n");
+ } else {
+ DEBUGP("can't expect_related(expect_orig)\n");
+ return 1;
+ }
+
+ /* alter expectation for PAC->PNS direction */
+ invert_tuplepr(&inv_t, &expect_reply->tuple);
+ expect_reply->saved_proto.gre.key = htons(nat_pptp_info->pns_call_id);
+ expect_reply->tuple.src.u.gre.key = htons(nat_pptp_info->pac_call_id);
+ expect_reply->tuple.dst.u.gre.key = htons(ct_pptp_info->pns_call_id);
+ inv_t.src.ip = orig_t->src.ip;
+ inv_t.dst.ip = orig_t->dst.ip;
+ inv_t.src.u.gre.key = htons(nat_pptp_info->pns_call_id);
+ inv_t.dst.u.gre.key = htons(ct_pptp_info->pac_call_id);
+
+ if (!ip_conntrack_expect_related(expect_reply)) {
+ DEBUGP("successfully registered expect\n");
+ } else {
+ DEBUGP("can't expect_related(expect_reply)\n");
+ ip_conntrack_unexpect_related(expect_orig);
+ return 1;
+ }
+
+ if (ip_ct_gre_keymap_add(ct, &expect_reply->tuple, 0) < 0) {
+ DEBUGP("can't register original keymap\n");
+ ip_conntrack_unexpect_related(expect_orig);
+ ip_conntrack_unexpect_related(expect_reply);
+ return 1;
+ }
+
+ if (ip_ct_gre_keymap_add(ct, &inv_t, 1) < 0) {
+ DEBUGP("can't register reply keymap\n");
+ ip_conntrack_unexpect_related(expect_orig);
+ ip_conntrack_unexpect_related(expect_reply);
+ ip_ct_gre_keymap_destroy(ct);
+ return 1;
+ }
+
+ return 0;
+}
+
+/* inbound packets == from PAC to PNS */
+static int
+pptp_inbound_pkt(struct sk_buff **pskb,
+ struct ip_conntrack *ct,
+ enum ip_conntrack_info ctinfo,
+ struct PptpControlHeader *ctlh,
+ union pptp_ctrl_union *pptpReq)
+{
+ struct ip_nat_pptp *nat_pptp_info = &ct->nat.help.nat_pptp_info;
+ u_int16_t msg, new_cid = 0, new_pcid, *pcid = NULL, *cid = NULL;
+
+ int ret = NF_ACCEPT, rv;
+
+ new_pcid = htons(nat_pptp_info->pns_call_id);
+
+ switch (msg = ntohs(ctlh->messageType)) {
+ case PPTP_OUT_CALL_REPLY:
+ pcid = &pptpReq->ocack.peersCallID;
+ cid = &pptpReq->ocack.callID;
+ break;
+ case PPTP_IN_CALL_CONNECT:
+ pcid = &pptpReq->iccon.peersCallID;
+ break;
+ case PPTP_IN_CALL_REQUEST:
+ /* only need to nat in case PAC is behind NAT box */
+ break;
+ case PPTP_WAN_ERROR_NOTIFY:
+ pcid = &pptpReq->wanerr.peersCallID;
+ break;
+ case PPTP_CALL_DISCONNECT_NOTIFY:
+ pcid = &pptpReq->disc.callID;
+ break;
+ case PPTP_SET_LINK_INFO:
+ pcid = &pptpReq->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 */
+ IP_NF_ASSERT(pcid);
+ DEBUGP("altering peer call id from 0x%04x to 0x%04x\n",
+ ntohs(*pcid), ntohs(new_pcid));
+
+ rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+ (void *)pcid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)),
+ sizeof(new_pcid), (char *)&new_pcid,
+ sizeof(new_pcid));
+ if (rv != NF_ACCEPT)
+ return rv;
+
+ if (new_cid) {
+ IP_NF_ASSERT(cid);
+ DEBUGP("altering call id from 0x%04x to 0x%04x\n",
+ ntohs(*cid), ntohs(new_cid));
+ rv = ip_nat_mangle_tcp_packet(pskb, ct, ctinfo,
+ (void *)cid - ((void *)ctlh - sizeof(struct pptp_pkt_hdr)),
+ sizeof(new_cid),
+ (char *)&new_cid,
+ sizeof(new_cid));
+ if (rv != NF_ACCEPT)
+ return rv;
+ }
+
+ /* check for earlier return value of 'switch' above */
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ /* great, at least we don't need to resize packets */
+ return NF_ACCEPT;
+}
+
+
+extern int __init ip_nat_proto_gre_init(void);
+extern void __exit ip_nat_proto_gre_fini(void);
+
+static int __init init(void)
+{
+ int ret;
+
+ DEBUGP("%s: registering NAT helper\n", __FILE__);
+
+ ret = ip_nat_proto_gre_init();
+ if (ret < 0)
+ return ret;
+
+ BUG_ON(ip_nat_pptp_hook_outbound);
+ ip_nat_pptp_hook_outbound = &pptp_outbound_pkt;
+
+ BUG_ON(ip_nat_pptp_hook_inbound);
+ ip_nat_pptp_hook_inbound = &pptp_inbound_pkt;
+
+ BUG_ON(ip_nat_pptp_hook_exp_gre);
+ ip_nat_pptp_hook_exp_gre = &pptp_exp_gre;
+
+ BUG_ON(ip_nat_pptp_hook_expectfn);
+ ip_nat_pptp_hook_expectfn = &pptp_nat_expected;
+
+ printk("ip_nat_pptp version %s loaded\n", IP_NAT_PPTP_VERSION);
+ return 0;
+}
+
+static void __exit fini(void)
+{
+ DEBUGP("cleanup_module\n" );
+
+ ip_nat_pptp_hook_expectfn = NULL;
+ ip_nat_pptp_hook_exp_gre = NULL;
+ ip_nat_pptp_hook_inbound = NULL;
+ ip_nat_pptp_hook_outbound = NULL;
+
+ ip_nat_proto_gre_fini();
+ /* Make sure noone calls it, meanwhile */
+ synchronize_net();
+
+ printk("ip_nat_pptp version %s unloaded\n", IP_NAT_PPTP_VERSION);
+}
+
+module_init(init);
+module_exit(fini);
diff --git a/net/ipv4/netfilter/ip_nat_proto_gre.c b/net/ipv4/netfilter/ip_nat_proto_gre.c
new file mode 100644
index 0000000..7c12854
--- /dev/null
+++ b/net/ipv4/netfilter/ip_nat_proto_gre.c
@@ -0,0 +1,214 @@
+/*
+ * ip_nat_proto_gre.c - Version 2.0
+ *
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/netfilter_ipv4/ip_nat.h>
+#include <linux/netfilter_ipv4/ip_nat_rule.h>
+#include <linux/netfilter_ipv4/ip_nat_protocol.h>
+#include <linux/netfilter_ipv4/ip_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 ip_conntrack_tuple *tuple,
+ enum ip_nat_manip_type maniptype,
+ const union ip_conntrack_manip_proto *min,
+ const union ip_conntrack_manip_proto *max)
+{
+ u_int32_t key;
+
+ if (maniptype == IP_NAT_MANIP_SRC)
+ key = tuple->src.u.gre.key;
+ else
+ key = tuple->dst.u.gre.key;
+
+ return ntohl(key) >= ntohl(min->gre.key)
+ && ntohl(key) <= ntohl(max->gre.key);
+}
+
+/* generate unique tuple ... */
+static int
+gre_unique_tuple(struct ip_conntrack_tuple *tuple,
+ const struct ip_nat_range *range,
+ enum ip_nat_manip_type maniptype,
+ const struct ip_conntrack *conntrack)
+{
+ static u_int16_t key;
+ u_int16_t *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 = ntohl(range->min.gre.key);
+ range_size = ntohl(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 = htonl(min + key % range_size);
+ if (!ip_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 ip_conntrack_tuple *tuple,
+ enum ip_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) {
+ /* key manipulation is always dest */
+ 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... */
+ *(gre_csum(greh)) =
+ ip_nat_cheat_check(~*(gre_key(greh)),
+ tuple->dst.u.gre.key,
+ *(gre_csum(greh)));
+ }
+ *(gre_key(greh)) = tuple->dst.u.gre.key;
+ break;
+ case GRE_VERSION_PPTP:
+ DEBUGP("call_id -> 0x%04x\n",
+ ntohl(tuple->dst.u.gre.key));
+ pgreh->call_id = htons(ntohl(tuple->dst.u.gre.key));
+ break;
+ default:
+ DEBUGP("can't nat unknown GRE version\n");
+ return 0;
+ break;
+ }
+ }
+ return 1;
+}
+
+/* print out a nat tuple */
+static unsigned int
+gre_print(char *buffer,
+ const struct ip_conntrack_tuple *match,
+ const struct ip_conntrack_tuple *mask)
+{
+ unsigned int len = 0;
+
+ if (mask->src.u.gre.key)
+ len += sprintf(buffer + len, "srckey=0x%x ",
+ ntohl(match->src.u.gre.key));
+
+ if (mask->dst.u.gre.key)
+ len += sprintf(buffer + len, "dstkey=0x%x ",
+ ntohl(match->src.u.gre.key));
+
+ return len;
+}
+
+/* print a range of keys */
+static unsigned int
+gre_print_range(char *buffer, const struct ip_nat_range *range)
+{
+ if (range->min.gre.key != 0
+ || range->max.gre.key != 0xFFFF) {
+ if (range->min.gre.key == range->max.gre.key)
+ return sprintf(buffer, "key 0x%x ",
+ ntohl(range->min.gre.key));
+ else
+ return sprintf(buffer, "keys 0x%u-0x%u ",
+ ntohl(range->min.gre.key),
+ ntohl(range->max.gre.key));
+ } else
+ return 0;
+}
+
+/* nat helper struct */
+static struct ip_nat_protocol gre = {
+ .name = "GRE",
+ .protonum = IPPROTO_GRE,
+ .manip_pkt = gre_manip_pkt,
+ .in_range = gre_in_range,
+ .unique_tuple = gre_unique_tuple,
+ .print = gre_print,
+ .print_range = gre_print_range,
+#if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
+ defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
+ .range_to_nfattr = ip_nat_port_range_to_nfattr,
+ .nfattr_to_range = ip_nat_port_nfattr_to_range,
+#endif
+};
+
+int __init ip_nat_proto_gre_init(void)
+{
+ return ip_nat_protocol_register(&gre);
+}
+
+void __exit ip_nat_proto_gre_fini(void)
+{
+ ip_nat_protocol_unregister(&gre);
+}