/* SPDX-License-Identifier: GPL-2.0-or-later */

  /* packet.h: Rx packet layout and definitions
   *

   * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.

   * Written by David Howells (dhowells@redhat.com)

   */
  
  #ifndef _LINUX_RXRPC_PACKET_H
  #define _LINUX_RXRPC_PACKET_H

  typedef u32	rxrpc_seq_t;	/* Rx message sequence number */
  typedef u32	rxrpc_serial_t;	/* Rx message serial number */
  typedef __be32	rxrpc_seq_net_t; /* on-the-wire Rx message sequence number */
  typedef __be32	rxrpc_serial_net_t; /* on-the-wire Rx message serial number */

  
  /*****************************************************************************/
  /*
   * on-the-wire Rx packet header
   * - all multibyte fields should be in network byte order
   */

  struct rxrpc_wire_header {

  	__be32		epoch;		/* client boot timestamp */

  #define RXRPC_RANDOM_EPOCH	0x80000000	/* Random if set, date-based if not */

  
  	__be32		cid;		/* connection and channel ID */
  #define RXRPC_MAXCALLS		4			/* max active calls per conn */
  #define RXRPC_CHANNELMASK	(RXRPC_MAXCALLS-1)	/* mask for channel ID */
  #define RXRPC_CIDMASK		(~RXRPC_CHANNELMASK)	/* mask for connection ID */

  #define RXRPC_CIDSHIFT		ilog2(RXRPC_MAXCALLS)	/* shift for connection ID */
  #define RXRPC_CID_INC		(1 << RXRPC_CIDSHIFT)	/* connection ID increment */

  
  	__be32		callNumber;	/* call ID (0 for connection-level packets) */

  	__be32		seq;		/* sequence number of pkt in call stream */
  	__be32		serial;		/* serial number of pkt sent to network */
  
  	uint8_t		type;		/* packet type */
  #define RXRPC_PACKET_TYPE_DATA		1	/* data */
  #define RXRPC_PACKET_TYPE_ACK		2	/* ACK */
  #define RXRPC_PACKET_TYPE_BUSY		3	/* call reject */
  #define RXRPC_PACKET_TYPE_ABORT		4	/* call/connection abort */
  #define RXRPC_PACKET_TYPE_ACKALL	5	/* ACK all outstanding packets on call */
  #define RXRPC_PACKET_TYPE_CHALLENGE	6	/* connection security challenge (SRVR->CLNT) */
  #define RXRPC_PACKET_TYPE_RESPONSE	7	/* connection secutity response (CLNT->SRVR) */
  #define RXRPC_PACKET_TYPE_DEBUG		8	/* debug info request */

  #define RXRPC_PACKET_TYPE_PARAMS	9	/* Parameter negotiation (unspec'd, ignore) */
  #define RXRPC_PACKET_TYPE_10		10	/* Ignored */
  #define RXRPC_PACKET_TYPE_11		11	/* Ignored */

  #define RXRPC_PACKET_TYPE_VERSION	13	/* version string request */

  
  	uint8_t		flags;		/* packet flags */
  #define RXRPC_CLIENT_INITIATED	0x01		/* signifies a packet generated by a client */
  #define RXRPC_REQUEST_ACK	0x02		/* request an unconditional ACK of this packet */
  #define RXRPC_LAST_PACKET	0x04		/* the last packet from this side for this call */
  #define RXRPC_MORE_PACKETS	0x08		/* more packets to come */
  #define RXRPC_JUMBO_PACKET	0x20		/* [DATA] this is a jumbo packet */
  #define RXRPC_SLOW_START_OK	0x20		/* [ACK] slow start supported */
  
  	uint8_t		userStatus;	/* app-layer defined status */

  #define RXRPC_USERSTATUS_SERVICE_UPGRADE 0x01	/* AuriStor service upgrade request */
  	

  	uint8_t		securityIndex;	/* security protocol ID */

  	union {
  		__be16	_rsvd;		/* reserved */
  		__be16	cksum;		/* kerberos security checksum */
  	};

  	__be16		serviceId;	/* service ID */

  } __packed;

  /*****************************************************************************/
  /*
   * jumbo packet secondary header
   * - can be mapped to read header by:
   *   - new_serial = serial + 1
   *   - new_seq = seq + 1
   *   - new_flags = j_flags
   *   - new__rsvd = j__rsvd
   *   - duplicating all other fields
   */

  struct rxrpc_jumbo_header {

  	uint8_t		flags;		/* packet flags (as per rxrpc_header) */
  	uint8_t		pad;

  	union {
  		__be16	_rsvd;		/* reserved */
  		__be16	cksum;		/* kerberos security checksum */
  	};

  };
  
  #define RXRPC_JUMBO_DATALEN	1412	/* non-terminal jumbo packet data length */

  #define RXRPC_JUMBO_SUBPKTLEN	(RXRPC_JUMBO_DATALEN + sizeof(struct rxrpc_jumbo_header))

  /*
   * The maximum number of subpackets that can possibly fit in a UDP packet is:
   *
   *	((max_IP - IP_hdr - UDP_hdr) / RXRPC_JUMBO_SUBPKTLEN) + 1
   *	= ((65535 - 28 - 28) / 1416) + 1
   *	= 46 non-terminal packets and 1 terminal packet.
   */
  #define RXRPC_MAX_NR_JUMBO	47

  /*****************************************************************************/
  /*
   * on-the-wire Rx ACK packet data payload
   * - all multibyte fields should be in network byte order
   */

  struct rxrpc_ackpacket {

  	__be16		bufferSpace;	/* number of packet buffers available */
  	__be16		maxSkew;	/* diff between serno being ACK'd and highest serial no
  					 * received */
  	__be32		firstPacket;	/* sequence no of first ACK'd packet in attached list */
  	__be32		previousPacket;	/* sequence no of previous packet received */
  	__be32		serial;		/* serial no of packet that prompted this ACK */
  
  	uint8_t		reason;		/* reason for ACK */
  #define RXRPC_ACK_REQUESTED		1	/* ACK was requested on packet */
  #define RXRPC_ACK_DUPLICATE		2	/* duplicate packet received */
  #define RXRPC_ACK_OUT_OF_SEQUENCE	3	/* out of sequence packet received */
  #define RXRPC_ACK_EXCEEDS_WINDOW	4	/* packet received beyond end of ACK window */
  #define RXRPC_ACK_NOSPACE		5	/* packet discarded due to lack of buffer space */
  #define RXRPC_ACK_PING			6	/* keep alive ACK */
  #define RXRPC_ACK_PING_RESPONSE		7	/* response to RXRPC_ACK_PING */
  #define RXRPC_ACK_DELAY			8	/* nothing happened since received packet */
  #define RXRPC_ACK_IDLE			9	/* ACK due to fully received ACK window */

  #define RXRPC_ACK__INVALID		10	/* Representation of invalid ACK reason */

  
  	uint8_t		nAcks;		/* number of ACKs */
  #define RXRPC_MAXACKS	255
  
  	uint8_t		acks[0];	/* list of ACK/NAKs */
  #define RXRPC_ACK_TYPE_NACK		0
  #define RXRPC_ACK_TYPE_ACK		1

  } __packed;

  /* Some ACKs refer to specific packets and some are general and can be updated. */
  #define RXRPC_ACK_UPDATEABLE ((1 << RXRPC_ACK_REQUESTED)	|	\
  			      (1 << RXRPC_ACK_PING_RESPONSE)	|	\
  			      (1 << RXRPC_ACK_DELAY)		|	\
  			      (1 << RXRPC_ACK_IDLE))

  /*
   * ACK packets can have a further piece of information tagged on the end
   */
  struct rxrpc_ackinfo {
  	__be32		rxMTU;		/* maximum Rx MTU size (bytes) [AFS 3.3] */
  	__be32		maxMTU;		/* maximum interface MTU size (bytes) [AFS 3.3] */
  	__be32		rwind;		/* Rx window size (packets) [AFS 3.4] */
  	__be32		jumbo_max;	/* max packets to stick into a jumbo packet [AFS 3.5] */
  };
  
  /*****************************************************************************/
  /*
   * Kerberos security type-2 challenge packet
   */
  struct rxkad_challenge {
  	__be32		version;	/* version of this challenge type */
  	__be32		nonce;		/* encrypted random number */
  	__be32		min_level;	/* minimum security level */
  	__be32		__padding;	/* padding to 8-byte boundary */

  } __packed;

  
  /*****************************************************************************/
  /*
   * Kerberos security type-2 response packet
   */
  struct rxkad_response {

  	__be32		version;	/* version of this response type */

  	__be32		__pad;
  
  	/* encrypted bit of the response */
  	struct {
  		__be32		epoch;		/* current epoch */
  		__be32		cid;		/* parent connection ID */
  		__be32		checksum;	/* checksum */
  		__be32		securityIndex;	/* security type */
  		__be32		call_id[4];	/* encrypted call IDs */
  		__be32		inc_nonce;	/* challenge nonce + 1 */
  		__be32		level;		/* desired level */
  	} encrypted;
  
  	__be32		kvno;		/* Kerberos key version number */
  	__be32		ticket_len;	/* Kerberos ticket length  */

  } __packed;

  #endif /* _LINUX_RXRPC_PACKET_H */