text: /* SPDX-License-Identifier: GPL-2.0-only */
  /*
   * Copyright (C) ST-Ericsson AB 2010
   * Author:	Sjur Brendeland
   */
  
  #ifndef CFPKT_H_
  #define CFPKT_H_
  #include <net/caif/caif_layer.h>
  #include <linux/types.h>
  struct cfpkt;
  
  /* Create a CAIF packet.
   * len: Length of packet to be created
   * @return New packet.
   */
  struct cfpkt *cfpkt_create(u16 len);
  
  /*
   * Destroy a CAIF Packet.
   * pkt Packet to be destoyed.
   */
  void cfpkt_destroy(struct cfpkt *pkt);
  
  /*
   * Extract header from packet.
   *
   * pkt Packet to extract header data from.
   * data Pointer to copy the header data into.
   * len Length of head data to copy.
   * @return zero on success and error code upon failure
   */
  int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len);
  
  static inline u8 cfpkt_extr_head_u8(struct cfpkt *pkt)
  {
  	u8 tmp;
  
  	cfpkt_extr_head(pkt, &tmp, 1);
  
  	return tmp;
  }
  
  static inline u16 cfpkt_extr_head_u16(struct cfpkt *pkt)
  {
  	__le16 tmp;
  
  	cfpkt_extr_head(pkt, &tmp, 2);
  
  	return le16_to_cpu(tmp);
  }
  
  static inline u32 cfpkt_extr_head_u32(struct cfpkt *pkt)
  {
  	__le32 tmp;
  
  	cfpkt_extr_head(pkt, &tmp, 4);
  
  	return le32_to_cpu(tmp);
  }
  
  /*
   * Peek header from packet.
   * Reads data from packet without changing packet.
   *
   * pkt Packet to extract header data from.
   * data Pointer to copy the header data into.
   * len Length of head data to copy.
   * @return zero on success and error code upon failure
   */
  int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len);
  
  /*
   * Extract header from trailer (end of packet).
   *
   * pkt Packet to extract header data from.
   * data Pointer to copy the trailer data into.
   * len Length of header data to copy.
   * @return zero on success and error code upon failure
   */
  int cfpkt_extr_trail(struct cfpkt *pkt, void *data, u16 len);
  
  /*
   * Add header to packet.
   *
   *
   * pkt Packet to add header data to.
   * data Pointer to data to copy into the header.
   * len Length of header data to copy.
   * @return zero on success and error code upon failure
   */
  int cfpkt_add_head(struct cfpkt *pkt, const void *data, u16 len);
  
  /*
   * Add trailer to packet.
   *
   *
   * pkt Packet to add trailer data to.
   * data Pointer to data to copy into the trailer.
   * len Length of trailer data to copy.
   * @return zero on success and error code upon failure
   */
  int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len);
  
  /*
   * Pad trailer on packet.
   * Moves data pointer in packet, no content copied.
   *
   * pkt Packet in which to pad trailer.
   * len Length of padding to add.
   * @return zero on success and error code upon failure
   */
  int cfpkt_pad_trail(struct cfpkt *pkt, u16 len);
  
  /*
   * Add a single byte to packet body (tail).
   *
   * pkt Packet in which to add byte.
   * data Byte to add.
   * @return zero on success and error code upon failure
   */
  int cfpkt_addbdy(struct cfpkt *pkt, const u8 data);
  
  /*
   * Add a data to packet body (tail).
   *
   * pkt Packet in which to add data.
   * data Pointer to data to copy into the packet body.
   * len Length of data to add.
   * @return zero on success and error code upon failure
   */
  int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len);
  
  /*
   * Checks whether there are more data to process in packet.
   * pkt Packet to check.
   * @return true if more data are available in packet false otherwise
   */
  bool cfpkt_more(struct cfpkt *pkt);
  
  /*
   * Checks whether the packet is erroneous,
   * i.e. if it has been attempted to extract more data than available in packet
   * or writing more data than has been allocated in cfpkt_create().
   * pkt Packet to check.
   * @return true on error false otherwise
   */
  bool cfpkt_erroneous(struct cfpkt *pkt);
  
  /*
   * Get the packet length.
   * pkt Packet to get length from.
   * @return Number of bytes in packet.
   */
  u16 cfpkt_getlen(struct cfpkt *pkt);
  
  /*
   * Set the packet length, by adjusting the trailer pointer according to length.
   * pkt Packet to set length.
   * len Packet length.
   * @return Number of bytes in packet.
   */
  int cfpkt_setlen(struct cfpkt *pkt, u16 len);
  
  /*
   * cfpkt_append - Appends a packet's data to another packet.
   * dstpkt:    Packet to append data into, WILL BE FREED BY THIS FUNCTION
   * addpkt:    Packet to be appended and automatically released,
   *            WILL BE FREED BY THIS FUNCTION.
   * expectlen: Packet's expected total length. This should be considered
   *            as a hint.
   * NB: Input packets will be destroyed after appending and cannot be used
   * after calling this function.
   * @return    The new appended packet.
   */
  struct cfpkt *cfpkt_append(struct cfpkt *dstpkt, struct cfpkt *addpkt,
  		      u16 expectlen);
  
  /*
   * cfpkt_split - Split a packet into two packets at the specified split point.
   * pkt: Packet to be split (will contain the first part of the data on exit)
   * pos: Position to split packet in two parts.
   * @return The new packet, containing the second part of the data.
   */
  struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos);
  
  /*
   * Iteration function, iterates the packet buffers from start to end.
   *
   * Checksum iteration function used to iterate buffers
   * (we may have packets consisting of a chain of buffers)
   * pkt:       Packet to calculate checksum for
   * iter_func: Function pointer to iteration function
   * chks:      Checksum calculated so far.
   * buf:       Pointer to the buffer to checksum
   * len:       Length of buf.
   * data:      Initial checksum value.
   * @return    Checksum of buffer.
   */
  
  int cfpkt_iterate(struct cfpkt *pkt,
  		u16 (*iter_func)(u16 chks, void *buf, u16 len),
  		u16 data);
  
  /* Map from a "native" packet (e.g. Linux Socket Buffer) to a CAIF packet.
   *  dir - Direction indicating whether this packet is to be sent or received.
   *  nativepkt  - The native packet to be transformed to a CAIF packet
   *  @return The mapped CAIF Packet CFPKT.
   */
  struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt);
  
  /* Map from a CAIF packet to a "native" packet (e.g. Linux Socket Buffer).
   *  pkt  - The CAIF packet to be transformed into a "native" packet.
   *  @return The native packet transformed from a CAIF packet.
   */
  void *cfpkt_tonative(struct cfpkt *pkt);
  
  /*
   * Returns packet information for a packet.
   * pkt Packet to get info from;
   * @return Packet information
   */
  struct caif_payload_info *cfpkt_info(struct cfpkt *pkt);
  
  /** cfpkt_set_prio - set priority for a CAIF packet.
   *
   * @pkt: The CAIF packet to be adjusted.
   * @prio: one of TC_PRIO_ constants.
   */
  void cfpkt_set_prio(struct cfpkt *pkt, int prio);
  
  #endif				/* CFPKT_H_ */
  