/*
 *  OsmoGGSN - Gateway GPRS Support Node
 *  Copyright (C) 2002, 2003, 2004 Mondru AB.
 *
 *  The contents of this file may be used under the terms of the GNU
 *  General Public License Version 2, provided that the above copyright
 *  notice and this permission notice is included in all copies or
 *  substantial portions of the software.
 *
 */

#ifndef _GTP_H
#define _GTP_H

#include <osmocom/core/utils.h>
#include <osmocom/core/defs.h>
#include <osmocom/core/timer.h>

#include "pdp.h"

#define GTP_MODE_GGSN 1
#define GTP_MODE_SGSN 2

#define GTP0_PORT	3386
#define GTP1C_PORT	2123
#define GTP1U_PORT	2152
#define PACKET_MAX      8196

#define GTP_MAX  0xffff		/* TODO: Choose right number */
#define GTP0_HEADER_SIZE 20
#define GTP1_HEADER_SIZE_SHORT  8
#define GTP1_HEADER_SIZE_LONG  12

#define SYSLOG_PRINTSIZE 255
#define ERRMSG_SIZE 255

#define RESTART_FILE "gsn_restart"
#define NAMESIZE 1024

/* GTP version 1 extension header type definitions. */
#define GTP_EXT_PDCP_PDU    0xC0	/* PDCP PDU Number */

/* GTP version 1 message type definitions. Also covers version 0 except *
 * for anonymous PDP context which was superceded in version 1 */

/* 0 For future use. */
#define GTP_ECHO_REQ          1	/* Echo Request */
#define GTP_ECHO_RSP          2	/* Echo Response */
#define GTP_NOT_SUPPORTED     3	/* Version Not Supported */
#define GTP_ALIVE_REQ         4	/* Node Alive Request */
#define GTP_ALIVE_RSP         5	/* Node Alive Response */
#define GTP_REDIR_REQ         6	/* Redirection Request */
#define GTP_REDIR_RSP         7	/* Redirection Response */
/* 8-15 For future use. */
#define GTP_CREATE_PDP_REQ   16	/* Create PDP Context Request */
#define GTP_CREATE_PDP_RSP   17	/* Create PDP Context Response */
#define GTP_UPDATE_PDP_REQ   18	/* Update PDP Context Request */
#define GTP_UPDATE_PDP_RSP   19	/* Update PDP Context Response */
#define GTP_DELETE_PDP_REQ   20	/* Delete PDP Context Request */
#define GTP_DELETE_PDP_RSP   21	/* Delete PDP Context Response */
						       /* 22-25 For future use. *//* In version GTP 1 anonomous PDP context */
#define GTP_ERROR            26	/* Error Indication */
#define GTP_PDU_NOT_REQ      27	/* PDU Notification Request */
#define GTP_PDU_NOT_RSP      28	/* PDU Notification Response */
#define GTP_PDU_NOT_REJ_REQ  29	/* PDU Notification Reject Request */
#define GTP_PDU_NOT_REJ_RSP  30	/* PDU Notification Reject Response */
#define GTP_SUPP_EXT_HEADER  31	/* Supported Extension Headers Notification */
#define GTP_SND_ROUTE_REQ    32	/* Send Routeing Information for GPRS Request */
#define GTP_SND_ROUTE_RSP    33	/* Send Routeing Information for GPRS Response */
#define GTP_FAILURE_REQ      34	/* Failure Report Request */
#define GTP_FAILURE_RSP      35	/* Failure Report Response */
#define GTP_MS_PRESENT_REQ   36	/* Note MS GPRS Present Request */
#define GTP_MS_PRESENT_RSP   37	/* Note MS GPRS Present Response */
/* 38-47 For future use. */
#define GTP_IDEN_REQ         48	/* Identification Request */
#define GTP_IDEN_RSP         49	/* Identification Response */
#define GTP_SGSN_CONTEXT_REQ 50	/* SGSN Context Request */
#define GTP_SGSN_CONTEXT_RSP 51	/* SGSN Context Response */
#define GTP_SGSN_CONTEXT_ACK 52	/* SGSN Context Acknowledge */
#define GTP_FWD_RELOC_REQ    53	/* Forward Relocation Request */
#define GTP_FWD_RELOC_RSP    54	/* Forward Relocation Response */
#define GTP_FWD_RELOC_COMPL  55	/* Forward Relocation Complete */
#define GTP_RELOC_CANCEL_REQ 56	/* Relocation Cancel Request */
#define GTP_RELOC_CANCEL_RSP 57	/* Relocation Cancel Response */
#define GTP_FWD_SRNS         58	/* Forward SRNS Context */
#define GTP_FWD_RELOC_ACK    59	/* Forward Relocation Complete Acknowledge */
#define GTP_FWD_SRNS_ACK     60	/* Forward SRNS Context Acknowledge */
/* 61-239 For future use. */
#define GTP_DATA_TRAN_REQ   240	/* Data Record Transfer Request */
#define GTP_DATA_TRAN_RSP   241	/* Data Record Transfer Response */
/* 242-254 For future use. */
#define GTP_GPDU            255	/* G-PDU */

extern const struct value_string gtp_type_names[];
static inline const char *gtp_type_name(uint8_t val)
{ return get_value_string(gtp_type_names, val); }

/* GTP information element cause codes from 29.060 v3.9.0 7.7 */
/*                                                            */
#define GTPCAUSE_REQ_IMSI                   0	/* Request IMSI */
#define GTPCAUSE_REQ_IMEI                   1	/* Request IMEI */
#define GTPCAUSE_REQ_IMSI_IMEI              2	/* Request IMSI and IMEI */
#define GTPCAUSE_NO_ID_NEEDED               3	/* No identity needed */
#define GTPCAUSE_MS_REFUSES_X               4	/* MS refuses */
#define GTPCAUSE_MS_NOT_RESP_X              5	/* MS is not GPRS responding */
#define GTPCAUSE_006                        6	/* For future use 6-48 */
#define GTPCAUSE_049                       49	/* Cause values reserved for GPRS charging protocol use (See GTP' in GSM 12.15) 49-63 */
#define GTPCAUSE_064                       64	/* For future use 64-127 */
#define GTPCAUSE_ACC_REQ                  128	/* Request accepted */
#define GTPCAUSE_129                      129	/* For future use 129-176 */
#define GTPCAUSE_177                      177	/* Cause values reserved for GPRS charging protocol use (See GTP' In GSM 12.15) 177-191 */
#define GTPCAUSE_NON_EXIST                192	/* Non-existent */
#define GTPCAUSE_INVALID_MESSAGE          193	/* Invalid message format */
#define GTPCAUSE_IMSI_NOT_KNOWN           194	/* IMSI not known */
#define GTPCAUSE_MS_DETACHED              195	/* MS is GPRS detached */
#define GTPCAUSE_MS_NOT_RESP              196	/* MS is not GPRS responding */
#define GTPCAUSE_MS_REFUSES               197	/* MS refuses */
#define GTPCAUSE_198                      198	/* For future use */
#define GTPCAUSE_NO_RESOURCES             199	/* No resources available */
#define GTPCAUSE_NOT_SUPPORTED            200	/* Service not supported */
#define GTPCAUSE_MAN_IE_INCORRECT         201	/* Mandatory IE incorrect */
#define GTPCAUSE_MAN_IE_MISSING           202	/* Mandatory IE missing */
#define GTPCAUSE_OPT_IE_INCORRECT         203	/* Optional IE incorrect */
#define GTPCAUSE_SYS_FAIL                 204	/* System failure */
#define GTPCAUSE_ROAMING_REST             205	/* Roaming Restriction */
#define GTPCAUSE_PTIMSI_MISMATCH          206	/* P-TMSI signature mismatch */
#define GTPCAUSE_CONN_SUSP                207	/* GPRS connection suspended */
#define GTPCAUSE_AUTH_FAIL                208	/* Authentication failure */
#define GTPCAUSE_USER_AUTH_FAIL           209	/* User authentication failed */
#define GTPCAUSE_CONTEXT_NOT_FOUND        210	/* Context not found */
#define GTPCAUSE_ADDR_OCCUPIED            211	/* All dynamic PDP addresses are occupied */
#define GTPCAUSE_NO_MEMORY                212	/* No memory is available */
#define GTPCAUSE_RELOC_FAIL               213	/* Relocation failure */
#define GTPCAUSE_UNKNOWN_MAN_EXTHEADER    214	/* Unknown mandatory extension header */
#define GTPCAUSE_SEM_ERR_TFT              215	/* Semantic error in the TFT operation */
#define GTPCAUSE_SYN_ERR_TFT              216	/* Syntactic error in the TFT operation */
#define GTPCAUSE_SEM_ERR_FILTER           217	/* Semantic errors in packet filter(s) */
#define GTPCAUSE_SYN_ERR_FILTER           218	/* Syntactic errors in packet filter(s) */
#define GTPCAUSE_MISSING_APN              219	/* Missing or unknown APN */
#define GTPCAUSE_UNKNOWN_PDP              220	/* Unknown PDP address or PDP type */
#define GTPCAUSE_221                      221	/* For Future Use 221-240 */
#define GTPCAUSE_241                      241	/* Cause Values Reserved For Gprs Charging Protocol Use (See Gtp' In Gsm 12.15) 241-255 */

struct ul66_t;
struct ul16_t;
struct pdp_t;

/* GTP 0 header.
 * Explanation to some of the fields:
 * SNDCP NPDU Number flag = 0 except for inter SGSN handover situations
 * SNDCP N-PDU LCC Number 0 = 0xff except for inter SGSN handover situations
 * Sequence number. Used for reliable delivery of signalling messages, and
 *   to discard "illegal" data messages.
 * Flow label. Is used to point a particular PDP context. Is used in data
 *   messages as well as signalling messages related to a particular context.
 * Tunnel ID is IMSI+NSAPI. Unique identifier of PDP context. Is somewhat
 *   redundant because the header also includes flow. */

struct gtp0_header {		/*    Descriptions from 3GPP 09.60 */
	uint8_t flags;		/* 01 bitfield, with typical values */
	/*    000..... Version: 1 (0) */
	/*    ...1111. Spare (7) */
	/*    .......0 SNDCP N-PDU Number flag (0) */
	uint8_t type;		/* 02 Message type. T-PDU = 0xff */
	uint16_t length;	/* 03 Length (of G-PDU excluding header) */
	uint16_t seq;		/* 05 Sequence Number */
	uint16_t flow;		/* 07 Flow Label ( = 0 for signalling) */
	uint8_t number;		/* 09 SNDCP N-PDU LCC Number ( 0 = 0xff) */
	uint8_t spare1;		/* 10 Spare */
	uint8_t spare2;		/* 11 Spare */
	uint8_t spare3;		/* 12 Spare */
	uint64_t tid;		/* 13 Tunnel ID */
} __attribute__((packed));	/* 20 */

#define GTP1HDR_F_NPDU	0x01
#define GTP1HDR_F_SEQ	0x02
#define GTP1HDR_F_EXT	0x04
#define GTP1HDR_F_GTP1	0x10
#define GTPHDR_F_VER(n)	((n) << 5)
#define GTPHDR_F_GET_VER(flags) ((flags)>>5)

struct gtp1_header_short {	/*    Descriptions from 3GPP 29060 */
	uint8_t flags;		/* 01 bitfield, with typical values */
	/*    001..... Version: 1 */
	/*    ...1.... Protocol Type: GTP=1, GTP'=0 */
	/*    ....0... Spare = 0 */
	/*    .....0.. Extension header flag: 0 */
	/*    ......0. Sequence number flag: 0 */
	/*    .......0 PN: N-PDU Number flag */
	uint8_t type;		/* 02 Message type. T-PDU = 0xff */
	uint16_t length;	/* 03 Length (of IP packet or signalling) */
	uint32_t tei;		/* 05 - 08 Tunnel Endpoint ID */
} __attribute__((packed));

struct gtp1_header_long {	/*    Descriptions from 3GPP 29060 */
	uint8_t flags;		/* 01 bitfield, with typical values */
	/*    001..... Version: 1 */
	/*    ...1.... Protocol Type: GTP=1, GTP'=0 */
	/*    ....0... Spare = 0 */
	/*    .....0.. Extension header flag: 0 */
	/*    ......1. Sequence number flag: 1 */
	/*    .......0 PN: N-PDU Number flag */
	uint8_t type;		/* 02 Message type. T-PDU = 0xff */
	uint16_t length;	/* 03 Length (of IP packet or signalling) */
	uint32_t tei;		/* 05 Tunnel Endpoint ID */
	uint16_t seq;		/* 10 Sequence Number */
	uint8_t npdu;		/* 11 N-PDU Number */
	uint8_t next;		/* 12 Next extension header type. Empty = 0 */
} __attribute__((packed));

struct gtp0_packet {
	struct gtp0_header h;
	uint8_t p[GTP_MAX];
} __attribute__ ((packed));

struct gtp1_packet_short {
	struct gtp1_header_short h;
	uint8_t p[GTP_MAX];
} __attribute__ ((packed));

struct gtp1_packet_long {
	struct gtp1_header_long h;
	uint8_t p[GTP_MAX];
} __attribute__ ((packed));

union gtp_packet {
	uint8_t flags;
	struct gtp0_packet gtp0;
	struct gtp1_packet_short gtp1s;
	struct gtp1_packet_long gtp1l;
} __attribute__ ((packed));

/* ***********************************************************
 * Information storage for each gsn instance
 *
 * Normally each instance of the application corresponds to
 * one instance of a gsn.
 *
 * In order to avoid global variables in the application, and
 * also in order to allow several instances of a gsn in the same
 * application this struct is provided in order to store all
 * relevant information related to the gsn.
 *
 * Note that this does not include information storage for '
 * each pdp context. This is stored in another struct.
 *************************************************************/

struct gsn_t {
	/* Parameters related to the network interface */

	int fd0;		/* GTP0 file descriptor */
	int fd1c;		/* GTP1 control plane file descriptor */
	int fd1u;		/* GTP0 user plane file descriptor */
	int mode;		/* Mode of operation: GGSN or SGSN */
	struct in_addr gsnc;	/* IP address of this gsn for signalling */
	struct in_addr gsnu;	/* IP address of this gsn for user traffic */

	/* Parameters related to signalling messages */
	uint16_t seq_next;	/* Next sequence number to use */
	int seq_first;		/* First packet in queue (oldest timeout) */
	int seq_last;		/* Last packet in queue (youngest timeout) */

	unsigned char restart_counter;	/* Increment on restart. Stored on disk */
	char *statedir;		/* Disk location for permanent storage */
	void *priv;		/* used by libgtp users to attach their own state) */
	struct queue_t *queue_req;	/* Request queue */
	struct queue_t *queue_resp;	/* Response queue */

	struct pdp_t pdpa[PDP_MAX];	/* PDP storage */
	struct pdp_t *hashtid[PDP_MAX];	/* Hash table for IMSI + NSAPI */

	struct osmo_timer_list queue_timer; /* internal queue_{req,resp} timer */

	/* Call back functions */
	int (*cb_delete_context) (struct pdp_t *);
	int (*cb_create_context_ind) (struct pdp_t *);
	int (*cb_unsup_ind) (struct sockaddr_in * peer);
	int (*cb_extheader_ind) (struct sockaddr_in * peer);
	int (*cb_conf) (int type, int cause, struct pdp_t * pdp, void *cbp);
	int (*cb_data_ind) (struct pdp_t * pdp, void *pack, unsigned len);
	int (*cb_recovery) (struct sockaddr_in * peer, uint8_t recovery);
	int (*cb_recovery2) (struct sockaddr_in * peer, struct pdp_t * pdp, uint8_t recovery);
	int (*cb_recovery3) (struct gsn_t *gsn, struct sockaddr_in *peer, struct pdp_t *pdp, uint8_t recovery);

	/* Counters */

	uint64_t err_socket;	/* Number of socket errors */
	uint64_t err_readfrom;	/* Number of readfrom errors */
	uint64_t err_sendto;	/* Number of sendto errors */
	uint64_t err_memcpy;	/* Number of memcpy */
	uint64_t err_queuefull;	/* Number of times queue was full */
	uint64_t err_seq;	/* Number of seq out of range */
	uint64_t err_address;	/* GSN address conversion failed */
	uint64_t err_unknownpdp;	/* GSN address conversion failed */
	uint64_t err_unknowntid;	/* Application supplied unknown imsi+nsapi */
	uint64_t err_cause;	/* Unexpected cause value received */
	uint64_t err_outofpdp;	/* Out of storage for PDP contexts */

	uint64_t empty;		/* Number of empty packets */
	uint64_t unsup;		/* Number of unsupported version 29.60 11.1.1 */
	uint64_t tooshort;	/* Number of too short headers 29.60 11.1.2 */
	uint64_t unknown;	/* Number of unknown messages 29.60 11.1.3 */
	uint64_t unexpect;	/* Number of unexpected messages 29.60 11.1.4 */
	uint64_t duplicate;	/* Number of duplicate or unsolicited replies */
	uint64_t missing;	/* Number of missing information field messages */
	uint64_t incorrect;	/* Number of incorrect information field messages */
	uint64_t invalid;	/* Number of invalid message format messages */
};

/* External API functions */

extern const char *gtp_version();
extern int gtp_new(struct gsn_t **gsn, char *statedir, struct in_addr *listen,
		   int mode);

extern int gtp_free(struct gsn_t *gsn);

extern int gtp_newpdp(struct gsn_t *gsn, struct pdp_t **pdp,
		      uint64_t imsi, uint8_t nsapi) OSMO_DEPRECATED("Use gtp_pdp_newpdp() instead");
extern int gtp_freepdp(struct gsn_t *gsn, struct pdp_t *pdp);
extern int gtp_freepdp_teardown(struct gsn_t *gsn, struct pdp_t *pdp);

extern int gtp_create_context_req(struct gsn_t *gsn, struct pdp_t *pdp,
				  void *cbp);

extern int gtp_set_cb_create_context_ind(struct gsn_t *gsn,
					 int (*cb_create_context_ind) (struct
								       pdp_t *
								       pdp));

extern int gtp_create_context_resp(struct gsn_t *gsn, struct pdp_t *pdp,
				   int cause);

extern int gtp_update_context(struct gsn_t *gsn, struct pdp_t *pdp,
			      void *cbp, struct in_addr *inetaddr);

extern int gtp_delete_context_req(struct gsn_t *gsn, struct pdp_t *pdp,
				  void *cbp, int teardown)
		OSMO_DEPRECATED("Use gtp_delete_context_req2() instead, to avoid freeing pdp ctx before reply");
extern int gtp_delete_context_req2(struct gsn_t *gsn, struct pdp_t *pdp,
				   void *cbp, int teardown);

extern int gtp_data_req(struct gsn_t *gsn, struct pdp_t *pdp,
			void *pack, unsigned len);

extern int gtp_set_cb_data_ind(struct gsn_t *gsn,
			       int (*cb_data_ind) (struct pdp_t * pdp,
						   void *pack, unsigned len));

extern int gtp_fd(struct gsn_t *gsn);
extern int gtp_decaps0(struct gsn_t *gsn);
extern int gtp_decaps1c(struct gsn_t *gsn);
extern int gtp_decaps1u(struct gsn_t *gsn);
extern int gtp_retrans(struct gsn_t *gsn) OSMO_DEPRECATED("This API is a no-op, libgtp already does the job internally");
extern int gtp_retranstimeout(struct gsn_t *gsn, struct timeval *timeout) OSMO_DEPRECATED("This API is a no-op and will return a 1 day timeout");

extern int gtp_set_cb_delete_context(struct gsn_t *gsn,
				     int (*cb_delete_context) (struct pdp_t *
							       pdp));
/*extern int gtp_set_cb_create_context(struct gsn_t *gsn,
  int (*cb_create_context) (struct pdp_t* pdp)); */

extern int gtp_set_cb_unsup_ind(struct gsn_t *gsn,
				int (*cb) (struct sockaddr_in * peer));

extern int gtp_set_cb_extheader_ind(struct gsn_t *gsn,
				    int (*cb) (struct sockaddr_in * peer));

extern int gtp_set_cb_conf(struct gsn_t *gsn,
			   int (*cb) (int type, int cause, struct pdp_t * pdp,
				      void *cbp));

int gtp_set_cb_recovery(struct gsn_t *gsn,
			int (*cb) (struct sockaddr_in * peer,
				   uint8_t recovery))
	OSMO_DEPRECATED("Use gtp_set_cb_recovery2() instead, to obtain pdp ctx originating the recovery");
int gtp_set_cb_recovery2(struct gsn_t *gsn,
			int (*cb) (struct sockaddr_in * peer,
				   struct pdp_t * pdp,
				   uint8_t recovery))
	OSMO_DEPRECATED("Use gtp_set_cb_recovery3() instead, to obtain gsn handling the recovery");;
int gtp_set_cb_recovery3(struct gsn_t *gsn,
			int (*cb) (struct gsn_t * gsn, struct sockaddr_in * peer,
				   struct pdp_t * pdp,
				   uint8_t recovery));

void gtp_clear_queues(struct gsn_t *gsn);

/* Internal functions (not part of the API */

extern int gtp_echo_req(struct gsn_t *gsn, int version, void *cbp,
			struct in_addr *inetaddrs);
extern int gtp_echo_resp(struct gsn_t *gsn, int version,
			 struct sockaddr_in *peer, int fd,
			 void *pack, unsigned len);
extern int gtp_echo_ind(struct gsn_t *gsn, int version,
			struct sockaddr_in *peer, int fd,
			void *pack, unsigned len);
extern int gtp_echo_conf(struct gsn_t *gsn, int version,
			 struct sockaddr_in *peer, void *pack, unsigned len);

extern int gtp_unsup_req(struct gsn_t *gsn, int version,
			 struct sockaddr_in *peer,
			 int fd, void *pack, unsigned len);
extern int gtp_unsup_ind(struct gsn_t *gsn, struct sockaddr_in *peer,
			 void *pack, unsigned len);

extern int gtp_create_pdp_resp(struct gsn_t *gsn, int version,
			       struct pdp_t *pdp, uint8_t cause);

extern int gtp_create_pdp_ind(struct gsn_t *gsn, int version,
			      struct sockaddr_in *peer, int fd,
			      void *pack, unsigned len);

extern int gtp_create_pdp_conf(struct gsn_t *gsn, int version,
			       struct sockaddr_in *peer,
			       void *pack, unsigned len);

extern int gtp_update_pdp_req(struct gsn_t *gsn, int version, void *cbp,
			      struct in_addr *inetaddr, struct pdp_t *pdp);

extern int gtp_delete_pdp_req(struct gsn_t *gsn, int version, void *cbp,
			      struct pdp_t *pdp);

extern int gtp_delete_pdp_resp(struct gsn_t *gsn, int version,
			       struct sockaddr_in *peer, int fd,
			       void *pack, unsigned len,
			       struct pdp_t *pdp, struct pdp_t *linked_pdp,
			       uint8_t cause, int teardown);

extern int gtp_delete_pdp_ind(struct gsn_t *gsn, int version,
			      struct sockaddr_in *peer, int fd,
			      void *pack, unsigned len);

extern int gtp_delete_pdp_conf(struct gsn_t *gsn, int version,
			       struct sockaddr_in *peer,
			       void *pack, unsigned len);

extern int ipv42eua(struct ul66_t *eua, struct in_addr *src);
extern int eua2ipv4(struct in_addr *dst, struct ul66_t *eua);
extern int gsna2in_addr(struct in_addr *dst, struct ul16_t *gsna);
extern int in_addr2gsna(struct ul16_t *gsna, struct in_addr *src);
extern const char *imsi_gtp2str(const uint64_t *imsi);

#endif /* !_GTP_H */