/****************************************************************************
 * include/nuttx/net/netdev.h
 * Defines architecture-specific device driver interfaces to the NuttX
 * network.
 *
 *   Copyright (C) 2007, 2009, 2011-2018 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Derived largely from portions of uIP with has a similar BSD-styple
 * license:
 *
 *   Copyright (c) 2001-2003, Adam Dunkels.
 *   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

#ifndef __INCLUDE_NUTTX_NET_NETDEV_H
#define __INCLUDE_NUTTX_NET_NETDEV_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/ioctl.h>
#include <stdint.h>

#include <nuttx/queue.h>

#include <net/if.h>
#include <net/ethernet.h>
#include <arpa/inet.h>

#include <nuttx/mm/iob.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/net.h>
#include <nuttx/net/ip.h>
#include <nuttx/nuttx.h>

#ifdef CONFIG_NET_IGMP
#  include <nuttx/net/igmp.h>
#endif

#ifdef CONFIG_NET_MLD
#  include <nuttx/net/mld.h>
#endif

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/* Determine the largest possible address */

#if defined(CONFIG_WIRELESS_IEEE802154) && defined(CONFIG_WIRELESS_PKTRADIO)
#  if CONFIG_PKTRADIO_ADDRLEN > 8
#    define RADIO_MAX_ADDRLEN CONFIG_PKTRADIO_ADDRLEN
#  else
#    define RADIO_MAX_ADDRLEN 8
#  endif
#elif defined(CONFIG_WIRELESS_IEEE802154)
#  define RADIO_MAX_ADDRLEN 8
#elif defined(CONFIG_WIRELESS_BLUETOOTH)
#  if CONFIG_PKTRADIO_ADDRLEN > 6
#    define RADIO_MAX_ADDRLEN CONFIG_PKTRADIO_ADDRLEN
#  else
#    define RADIO_MAX_ADDRLEN 6
#  endif
#else /* if defined(CONFIG_WIRELESS_PKTRADIO) */
#  define RADIO_MAX_ADDRLEN CONFIG_PKTRADIO_ADDRLEN
#endif

/* Helper macros for network device statistics */

#ifdef CONFIG_NETDEV_STATISTICS
#  define NETDEV_RESET_STATISTICS(dev) \
     memset(&(dev)->d_statistics, 0, sizeof(struct netdev_statistics_s))

#  define _NETDEV_STATISTIC(dev,name) ((dev)->d_statistics.name++)
#  define _NETDEV_ERROR(dev,name) \
     do \
       { \
         (dev)->d_statistics.name++; \
         (dev)->d_statistics.errors++; \
       } \
     while (0)

#  define NETDEV_RXPACKETS(dev)   _NETDEV_STATISTIC(dev,rx_packets)
#  define NETDEV_RXFRAGMENTS(dev) _NETDEV_STATISTIC(dev,rx_fragments)
#  define NETDEV_RXERRORS(dev)    _NETDEV_ERROR(dev,rx_errors)
#  ifdef CONFIG_NET_IPv4
#    define NETDEV_RXIPV4(dev)    _NETDEV_STATISTIC(dev,rx_ipv4)
#  else
#    define NETDEV_RXIPV4(dev)
#  endif
#  ifdef CONFIG_NET_IPv6
#    define NETDEV_RXIPV6(dev)    _NETDEV_STATISTIC(dev,rx_ipv6)
#  else
#    define NETDEV_RXIPV6(dev)
#  endif
#  ifdef CONFIG_NET_ARP
#    define NETDEV_RXARP(dev)     _NETDEV_STATISTIC(dev,rx_arp)
#  else
#    define NETDEV_RXARP(dev)
#  endif
#  define NETDEV_RXDROPPED(dev)   _NETDEV_STATISTIC(dev,rx_dropped)

#  define NETDEV_TXPACKETS(dev)   _NETDEV_STATISTIC(dev,tx_packets)
#  define NETDEV_TXDONE(dev)      _NETDEV_STATISTIC(dev,tx_done)
#  define NETDEV_TXERRORS(dev)    _NETDEV_ERROR(dev,tx_errors)
#  define NETDEV_TXTIMEOUTS(dev)  _NETDEV_ERROR(dev,tx_timeouts)

#  define NETDEV_ERRORS(dev)      _NETDEV_STATISTIC(dev,errors)

#else
#  define NETDEV_RESET_STATISTICS(dev)
#  define NETDEV_RXPACKETS(dev)
#  define NETDEV_RXFRAGMENTS(dev)
#  define NETDEV_RXERRORS(dev)
#  define NETDEV_RXIPV4(dev)
#  define NETDEV_RXIPV6(dev)
#  define NETDEV_RXARP(dev)
#  define NETDEV_RXDROPPED(dev)

#  define NETDEV_TXPACKETS(dev)
#  define NETDEV_TXDONE(dev)
#  define NETDEV_TXERRORS(dev)
#  define NETDEV_TXTIMEOUTS(dev)

#  define NETDEV_ERRORS(dev)
#endif

/* There are some helper pointers for accessing the contents of the IP
 * headers
 */

#define IPBUF(hl) ((FAR void *)\
                   &dev->d_iob->io_data[CONFIG_NET_LL_GUARDSIZE + (hl)])

#define IPv4BUF ((FAR struct ipv4_hdr_s *)IPBUF(0))
#define IPv6BUF ((FAR struct ipv6_hdr_s *)IPBUF(0))

/****************************************************************************
 * Public Types
 ****************************************************************************/

#ifdef CONFIG_NETDEV_STATISTICS
/* If CONFIG_NETDEV_STATISTICS is enabled and if the driver supports
 * statistics, then this structure holds the counts of network driver
 * events.
 */

struct netdev_statistics_s
{
  /* Rx Status */

  uint32_t rx_packets;     /* Number of packets received */
  uint32_t rx_fragments;   /* Number of fragments received */
  uint32_t rx_errors;      /* Number of receive errors */
#ifdef CONFIG_NET_IPv4
  uint32_t rx_ipv4;        /* Number of Rx IPv4 packets received */
#endif
#ifdef CONFIG_NET_IPv6
  uint32_t rx_ipv6;        /* Number of Rx IPv6 packets received */
#endif
#ifdef CONFIG_NET_ARP
  uint32_t rx_arp;         /* Number of Rx ARP packets received */
#endif
  uint32_t rx_dropped;     /* Unsupported Rx packets received */

  /* Tx Status */

  uint32_t tx_packets;     /* Number of Tx packets queued */
  uint32_t tx_done;        /* Number of packets completed */
  uint32_t tx_errors;      /* Number of receive errors (incl timeouts) */
  uint32_t tx_timeouts;    /* Number of Tx timeout errors */

  /* Other status */

  uint32_t errors;         /* Total number of errors */
};
#endif

#if defined(CONFIG_NET_6LOWPAN) || defined(CONFIG_NET_BLUETOOTH) || \
    defined(CONFIG_NET_IEEE802154)
/* This structure is used to represent addresses of varying length.  This
 * structure is used to represent the address assigned to a radio.
 *
 * NOTE: the Bluetooth address is not variable, but shares struct
 * radio_driver_s which depends on this type.
 */

struct netdev_maxaddr_s
{
  uint8_t nm_addr[RADIO_MAX_ADDRLEN];
};

struct netdev_varaddr_s
{
  uint8_t nv_addr[RADIO_MAX_ADDRLEN];
  uint8_t nv_addrlen;
};
#endif

/* This structure collects information that is specific to a specific network
 * interface driver.  If the hardware platform supports only a single
 * instance of this structure.
 */

struct devif_callback_s; /* Forward reference */

struct net_driver_s
{
  /* This link is used to maintain a single-linked list of ethernet drivers.
   * Must be the first field in the structure due to blink type casting.
   */

#ifdef CONFIG_NET
  FAR struct net_driver_s *flink;

  /* This is the name of network device assigned when netdev_register was
   * called.
   * This name is only used to support socket ioctl lookups by device name
   * Examples: "eth0"
   */

  char d_ifname[IFNAMSIZ];
#endif

  /* Drivers interface flags.  See IFF_* definitions in include/net/if.h */

  uint32_t d_flags;

  /* Multi network devices using multiple link layer protocols are
   * supported
   */

  uint8_t d_lltype;             /* See enum net_lltype_e */
  uint8_t d_llhdrlen;           /* Link layer header size */
#ifdef CONFIG_NETDEV_IFINDEX
  uint8_t d_ifindex;            /* Device index */
#endif

  uint16_t d_pktsize;           /* Maximum packet size */

  /* Link layer address */

#if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_NET_6LOWPAN) || \
    defined(CONFIG_NET_BLUETOOTH) || defined(CONFIG_NET_IEEE802154) || \
    defined(CONFIG_NET_TUN)
  union
  {
# if defined(CONFIG_NET_ETHERNET) || defined(CONFIG_NET_TUN)
    /* Ethernet device identity */

    struct ether_addr ether;    /* Device Ethernet MAC address */
# endif

# if defined(CONFIG_NET_6LOWPAN) || defined(CONFIG_NET_BLUETOOTH) || \
    defined(CONFIG_NET_IEEE802154)
  /* The address assigned to an IEEE 802.15.4 or generic packet radio. */

    struct netdev_varaddr_s radio;
# endif
  } d_mac;
#endif

  /* Network identity */

#ifdef CONFIG_NET_IPv4
  in_addr_t      d_ipaddr;      /* Host IPv4 address assigned to the network interface */
  in_addr_t      d_draddr;      /* Default router IP address */
  in_addr_t      d_netmask;     /* Network subnet mask */
#endif

#ifdef CONFIG_NET_IPv6
  net_ipv6addr_t d_ipv6addr;    /* Host IPv6 address assigned to the network interface */
  net_ipv6addr_t d_ipv6draddr;  /* Default router IPv6 address */
  net_ipv6addr_t d_ipv6netmask; /* Network IPv6 subnet mask */
#endif
  /* This is a new design that uses d_iob as packets input and output
   * buffer which used by some NICs such as celluler net driver. Case for
   * data input, note that d_iob maybe a linked chain only when using
   * d_iob to store reassembled datagrams, otherwise d_iob uses only
   * one buffer to hold the entire frame data. Case for data output, note
   * that d_iob also maybe a linked chain only when using d_iob to
   * store fragmented datagrams, otherwise d_iob uses only one buffer
   * to hold the entire frame data.
   *
   * In all cases mentioned above, d_buf always points to the beginning
   * of the first buffer of d_iob.
   */

  FAR struct iob_s *d_iob;

  /* The d_buf array is used to hold incoming and outgoing packets. The
   * device driver should place incoming data into this buffer.  When sending
   * data, the device driver should read the link level headers and the
   * TCP/IP headers from this buffer.  The size of the link level headers is
   * configured by the NET_LL_HDRLEN(dev) define.
   *
   * The network will handle only a single buffer for both incoming and
   * outgoing packets.  However, the driver design may be concurrently
   * sending and filling separate, break-off buffers.  That buffer
   * management must be controlled by the driver.
   *
   * The d_buf array must be aligned to two-byte, 16-bit address boundaries
   * in order to support aligned 16-bit accesses performed by the network.
   */

  FAR uint8_t *d_buf;

  /* d_appdata points to the location where application data can be read from
   * or written to in the packet buffer.
   */

  FAR uint8_t *d_appdata;

#ifdef CONFIG_NET_TCPURGDATA
  /* This pointer points to any urgent TCP data that has been received. Only
   * present if compiled with support for urgent data(CONFIG_NET_TCPURGDATA).
   */

  FAR uint8_t *d_urgdata;

  /* Length of the (received) urgent data */

  uint16_t d_urglen;
#endif

/* The length of the packet in the d_buf buffer.
 *
 * Holds the length of the packet in the d_buf buffer.
 *
 * When the network device driver calls the network input function,
 * d_len should be set to the length of the packet in the d_buf
 * buffer.
 *
 * When sending packets, the device driver should use the contents of
 * the d_len variable to determine the length of the outgoing
 * packet.
 */

  uint16_t d_len;

  /* When d_buf contains outgoing xmit data, d_sndlen is non-zero and
   * represents the amount of application data after d_appdata
   */

  uint16_t d_sndlen;

  /* Multicast group support */

#ifdef CONFIG_NET_IGMP
  sq_queue_t d_igmp_grplist;    /* IGMP group list */
#endif
#ifdef CONFIG_NET_MLD
  struct mld_netdev_s d_mld;    /* MLD state information */
#endif

#ifdef CONFIG_NETDEV_STATISTICS
  /* If CONFIG_NETDEV_STATISTICS is enabled and if the driver supports
   * statistics, then this structure holds the counts of network driver
   * events.
   */

  struct netdev_statistics_s d_statistics;
#endif

  /* Application callbacks:
   *
   * Network device event handlers are retained in a 'list' and are called
   * for events specified in the flags set within struct devif_callback_s.
   *
   * There are two lists associated with each device:
   *
   *   1) d_conncb - For connection/port oriented events for certain
   *      socket-less packet transfers.  There events include:
   *
   *        ICMP data receipt:     ICMP_NEWDATA, ICMPv6_NEWDATA
   *        Driver Tx poll events: ARP_POLL, ICMP_POLL. ICMPv6_POLL
   *        IP Forwarding:         IPFWD_POLL
   *
   *   2) d_devcb - For non-data, device related events that apply to all
   *      transfers or connections involving this device:
   *
   *        NETDEV_DOWN - The network is down
   */

  FAR struct devif_callback_s *d_conncb;      /* This is the list head */
  FAR struct devif_callback_s *d_conncb_tail; /* This is the list tail */
  FAR struct devif_callback_s *d_devcb;

  /* Driver callbacks */

  int (*d_ifup)(FAR struct net_driver_s *dev);
  int (*d_ifdown)(FAR struct net_driver_s *dev);
  int (*d_txavail)(FAR struct net_driver_s *dev);
#ifdef CONFIG_NET_MCASTGROUP
  int (*d_addmac)(FAR struct net_driver_s *dev, FAR const uint8_t *mac);
  int (*d_rmmac)(FAR struct net_driver_s *dev, FAR const uint8_t *mac);
#endif
#ifdef CONFIG_NETDEV_IOCTL
  int (*d_ioctl)(FAR struct net_driver_s *dev, int cmd,
                 unsigned long arg);
#endif

  /* Drivers may attached device-specific, private information */

  FAR void *d_private;
};

typedef CODE int (*devif_poll_callback_t)(FAR struct net_driver_s *dev);

/****************************************************************************
 * Public Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Network device driver functions
 *
 * These functions are used by a network device driver for interacting
 * with the NuttX network.
 *
 * Process an incoming IP packet.
 *
 * This function should be called when the device driver has received
 * a packet from the network. The packet from the device driver must
 * be present in the d_buf buffer, and the length of the packet
 * should be placed in the d_len field.
 *
 * When the function returns, there may be an outbound packet placed
 * in the d_buf packet buffer. If so, the d_len field is set to
 * the length of the packet. If no packet is to be sent out, the
 * d_len field is set to 0.
 *
 * The usual way of calling the function is presented by the source
 * code below.
 *
 *     dev->d_len = devicedriver_poll();
 *     if (dev->d_len > 0)
 *       {
 *         ipv4_input(dev);
 *         if (dev->d_len > 0)
 *           {
 *             devicedriver_send();
 *           }
 *       }
 *
 * Note: If you are writing a network device driver that needs ARP
 * (Address Resolution Protocol), e.g., when running the network over
 * Ethernet, you will need to call the network ARP code before calling
 * this function:
 *
 *     dev->d_len = ethernet_devicedrver_poll();
 *     if (dev->d_len > 0)
 *       {
 *         if (ETHBUF->type == HTONS(ETHTYPE_IP))
 *           {
 *             arp_ipin();
 *             ipv4_input(dev);
 *             if (dev->d_len > 0)
 *               {
 *                 arp_out();
 *                 devicedriver_send();
 *               }
 *           }
 *         else if (ETHBUF->type == HTONS(ETHTYPE_ARP))
 *           {
 *             arp_input();
 *             if (dev->d_len > 0)
 *               {
 *                 devicedriver_send();
 *               }
 *           }
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
int ipv4_input(FAR struct net_driver_s *dev);
#endif

#ifdef CONFIG_NET_IPv6
int ipv6_input(FAR struct net_driver_s *dev);
#endif

#ifdef CONFIG_NET_6LOWPAN
struct radio_driver_s;   /* Forward reference.  See radiodev.h */
struct iob_s;            /* Forward reference See iob.h */

int sixlowpan_input(FAR struct radio_driver_s *ieee,
                    FAR struct iob_s *framelist, FAR const void *metadata);
#endif

/****************************************************************************
 * Polling of connections
 *
 * These functions will traverse each active network connection structure
 * and perform appropriate operations:  devif_poll() will perform TCP
 * and UDP polling operations. devif_poll() may be called asynchronously
 * from the network driver can accept another outgoing packet.
 *
 * In both cases, these functions will call the provided callback function
 * for every active connection. Polling will continue until all connections
 * have been polled or until the user-supplied function returns a non-zero
 * value (which it should do only if it cannot accept further write data).
 *
 * When the callback function is called, there may be an outbound packet
 * waiting for service in the device packet buffer, and if so the d_len field
 * is set to a value larger than zero. The device driver should then send
 * out the packet.
 *
 * Example:
 *   int driver_callback(FAR struct net_driver_s *dev)
 *   {
 *     if (dev->d_len > 0)
 *       {
 *         devicedriver_send();
 *         return 1; <-- Terminates polling if necessary
 *       }
 *     return 0;
 *   }
 *
 *   ...
 *   devif_poll(dev, driver_callback);
 *
 * Note: If you are writing a network device driver that needs ARP (Address
 * Resolution Protocol), e.g., when running the networ over Ethernet, you
 * will need to call the arp_out() function in the callback function
 * before sending the packet:
 *
 *   int driver_callback(FAR struct net_driver_s *dev)
 *   {
 *     if (dev->d_len > 0)
 *       {
 *         arp_out();
 *         devicedriver_send();
 *         return 1; <-- Terminates polling if necessary
 *       }
 *
 *     return 0;
 *   }
 *
 *   Compatible with all old flat buffer NICs
 *
 *                 tcp_poll()/udp_poll()/pkt_poll()/...(l3/l4)
 *                            /              \
 *                           /                \
 * devif_poll_[l3/l4]_connections()     devif_iob_send() (nocopy:udp/icmp/..)
 *            /                                   \      (copy:tcp)
 *           /                                     \
 *   devif_iob_poll(devif_poll_callback())  devif_poll_callback()
 *        /                                           \
 *       /                                             \
 *  devif_poll("NIC"_txpoll)                     "NIC"_send()(dev->d_buf)
 *
 ****************************************************************************/

int devif_poll(FAR struct net_driver_s *dev, devif_poll_callback_t callback);

/****************************************************************************
 * Name: neighbor_out
 *
 * Description:
 *   This function should be called before sending out an IPv6 packet. The
 *   function checks the destination IPv6 address of the IPv6 packet to see
 *   what L2 address that should be used as a destination L2 address.
 *
 *   If the destination IPv6 address is in the local network (determined
 *   by logical ANDing of netmask and our IPv6 address), the function
 *   checks the Neighbor Table to see if an entry for the destination IPv6
 *   address is found.  If so, an L2 header is pre-pended at the beginning
 *   of the packet and the function returns.
 *
 *   If no Neighbor Table entry is found for the destination IPv6 address,
 *   the packet in the d_buf is replaced by an ICMPv6 Neighbor Solicit
 *   request packet for the IPv6 address. The IPv6 packet is dropped and
 *   it is assumed that the higher level protocols (e.g., TCP) eventually
 *   will retransmit the dropped packet.
 *
 *   Upon return in either the case, a packet to be sent is present in the
 *   d_buf buffer and the d_len field holds the length of the L2 frame that
 *   should be transmitted.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv6
void neighbor_out(FAR struct net_driver_s *dev);
#endif /* CONFIG_NET_IPv6 */

/****************************************************************************
 * Name: netdev_ifup / netdev_ifdown
 *
 * Description:
 *   Bring the interface up/down
 *
 ****************************************************************************/

int netdev_ifup(FAR struct net_driver_s *dev);
int netdev_ifdown(FAR struct net_driver_s *dev);

/****************************************************************************
 * Carrier detection
 *
 * Call netdev_carrier_on when the carrier has become available and the
 * device is ready to receive/transmit packets.
 *
 * Call detdev_carrier_off when the carrier disappeared and the device has
 * moved into non operational state.
 *
 ****************************************************************************/

int netdev_carrier_on(FAR struct net_driver_s *dev);
int netdev_carrier_off(FAR struct net_driver_s *dev);

/****************************************************************************
 * Name: chksum
 *
 * Description:
 *   Calculate the raw change sum over the memory region described by
 *   data and len.
 *
 * Input Parameters:
 *   sum  - Partial calculations carried over from a previous call to
 *          chksum().  This should be zero on the first time that check
 *          sum is called.
 *   data - Beginning of the data to include in the checksum.
 *   len  - Length of the data to include in the checksum.
 *
 * Returned Value:
 *   The updated checksum value.
 *
 ****************************************************************************/

uint16_t chksum(uint16_t sum, FAR const uint8_t *data, uint16_t len);

/****************************************************************************
 * Name: chksum_iob
 *
 * Description:
 *   Calculate the Internet checksum over an iob chain buffer.
 *
 * Input Parameters:
 *   sum    - Partial calculations carried over from a previous call to
 *            chksum().  This should be zero on the first time that check
 *            sum is called.
 *   iob    - An iob chain buffer over which the checksum is to be computed.
 *   offset - Specifies the byte offset of the start of valid data.
 *
 * Returned Value:
 *   The updated checksum value.
 *
 ****************************************************************************/

uint16_t chksum_iob(uint16_t sum, FAR struct iob_s *iob, uint16_t offset);

/****************************************************************************
 * Name: net_chksum
 *
 * Description:
 *   Calculate the Internet checksum over a buffer.
 *
 *   The Internet checksum is the one's complement of the one's complement
 *   sum of all 16-bit words in the buffer.
 *
 *   See RFC1071.
 *
 *   If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
 *   provided by architecture-specific logic.
 *
 * Input Parameters:
 *
 *   buf - A pointer to the buffer over which the checksum is to be computed.
 *
 *   len - The length of the buffer over which the checksum is to be
 *         computed.
 *
 * Returned Value:
 *   The Internet checksum of the buffer.
 *
 ****************************************************************************/

uint16_t net_chksum(FAR uint16_t *data, uint16_t len);

/****************************************************************************
 * Name: net_chksum_iob
 *
 * Description:
 *   Calculate the Internet checksum over an iob chain buffer.
 *
 *   The Internet checksum is the one's complement of the one's complement
 *   sum of all 16-bit words in the buffer.
 *
 *   See RFC1071.
 *
 *   If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
 *   provided by architecture-specific logic.
 *
 * Input Parameters:
 *   sum    - Partial calculations carried over from a previous call to
 *            chksum().  This should be zero on the first time that check
 *            sum is called.
 *   iob    - An iob chain buffer over which the checksum is to be computed.
 *   offset - Specifies the byte offset of the start of valid data.
 *
 * Returned Value:
 *   The Internet checksum of the given iob chain buffer.
 *
 ****************************************************************************/

uint16_t net_chksum_iob(uint16_t sum, FAR struct iob_s *iob,
                        uint16_t offset);

/****************************************************************************
 * Name: ipv4_upperlayer_chksum
 *
 * Description:
 *   Perform the checksum calculation over the IPv4, protocol headers, and
 *   data payload as necessary.
 *
 * Input Parameters:
 *   dev   - The network driver instance.  The packet data is in the d_buf
 *           of the device.
 *   proto - The protocol being supported
 *
 * Returned Value:
 *   The calculated checksum
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
uint16_t ipv4_upperlayer_chksum(FAR struct net_driver_s *dev, uint8_t proto);
#endif /* CONFIG_NET_IPv4 */

/****************************************************************************
 * Name: ipv6_upperlayer_chksum
 *
 * Description:
 *   Perform the checksum calculation over the IPv6, protocol headers, and
 *   data payload as necessary.
 *
 * Input Parameters:
 *   dev   - The network driver instance.  The packet data is in the d_buf
 *           of the device.
 *   proto - The protocol being supported
 *   iplen - The size of the IPv6 header.  This may be larger than
 *           IPv6_HDRLEN the IPv6 header if IPv6 extension headers are
 *           present.
 *
 * Returned Value:
 *   The calculated checksum
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv6
uint16_t ipv6_upperlayer_chksum(FAR struct net_driver_s *dev,
                                uint8_t proto, unsigned int iplen);
#endif /* CONFIG_NET_IPv6 */

/****************************************************************************
 * Name: ipv4_chksum
 *
 * Description:
 *   Calculate the IPv4 header checksum of the packet header in d_buf.
 *
 *   The IPv4 header checksum is the Internet checksum of the 20 bytes of
 *   the IPv4 header.
 *
 *   If CONFIG_NET_ARCH_CHKSUM is defined, then this function must be
 *   provided by architecture-specific logic.
 *
 * Returned Value:
 *   The IPv4 header checksum of the IPv4 header in the d_buf buffer.
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
uint16_t ipv4_chksum(FAR struct ipv4_hdr_s *ipv4);
#endif /* CONFIG_NET_IPv4 */

/****************************************************************************
 * Name: net_incr32
 *
 * Description:
 *
 *   Carry out a 32-bit addition.
 *
 *   By defining CONFIG_NET_ARCH_INCR32, the architecture can replace
 *   net_incr32 with hardware assisted solutions.
 *
 * Input Parameters:
 *   op32 - A pointer to a 4-byte array representing a 32-bit integer in
 *          network byte order (big endian).  This value may not be word
 *          aligned. The value pointed to by op32 is modified in place
 *
 *   op16 - A 16-bit integer in host byte order.
 *
 ****************************************************************************/

void net_incr32(FAR uint8_t *op32, uint16_t op16);

/****************************************************************************
 * Name: netdev_ipv4_hdrlen
 *
 * Description:
 *    Provide header length for interface based on device
 *
 * Input Parameters:
 *   dev Device structure pointer
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv4
#  define netdev_ipv4_hdrlen(dev) (dev->d_llhdrlen)
#endif /* CONFIG_NET_IPv4 */

/****************************************************************************
 * Name: netdev_ipv6_hdrlen
 *
 * Description:
 *    Provide header length for interface based on device
 *
 * Input Parameters:
 *   dev Device structure pointer
 *
 ****************************************************************************/

#ifdef CONFIG_NET_IPv6
#  define netdev_ipv6_hdrlen(dev) dev->d_llhdrlen
#endif /* CONFIG_NET_IPv6 */

/****************************************************************************
 * Name: netdev_lladdrsize
 *
 * Description:
 *   Returns the size of the MAC address associated with a network device.
 *
 * Input Parameters:
 *   dev - A reference to the device of interest
 *
 * Returned Value:
 *   The size of the MAC address associated with this device
 *
 ****************************************************************************/

int netdev_lladdrsize(FAR struct net_driver_s *dev);

/****************************************************************************
 * Name: netdev_iob_prepare
 *
 * Description:
 *   Prepare data buffer for a given NIC
 *   The iob offset will be updated to l2 gruard size by default:
 *  ----------------------------------------------------------------
 *  |                     iob entry                                |
 *  ---------------------------------------------------------------|
 *  |<--- CONFIG_NET_LL_GUARDSIZE -->|<--- io_len/io_pktlen(0) --->|
 *  ---------------------------------------------------------------|
 *
 * Assumptions:
 *   The caller has locked the network.
 *
 * Returned Value:
 *   A non-zero copy is returned on success.
 *
 ****************************************************************************/

int netdev_iob_prepare(FAR struct net_driver_s *dev, bool throttled,
                       unsigned int timeout);

/****************************************************************************
 * Name: netdev_iob_replace
 *
 * Description:
 *   Replace buffer resources for a given NIC
 *
 * Assumptions:
 *   The caller has locked the network and new iob is prepared with
 *   l2 gruard size as offset.
 *
 ****************************************************************************/

void netdev_iob_replace(FAR struct net_driver_s *dev, FAR struct iob_s *iob);

/****************************************************************************
 * Name: netdev_iob_clear
 *
 * Description:
 *   Clean up buffer resources for a given NIC
 *
 * Assumptions:
 *   The caller has locked the network and dev->d_iob has been
 *   released or taken away.
 *
 ****************************************************************************/

void netdev_iob_clear(FAR struct net_driver_s *dev);

/****************************************************************************
 * Name: netdev_iob_release
 *
 * Description:
 *   Release buffer resources for a given NIC
 *
 * Assumptions:
 *   The caller has locked the network.
 *
 ****************************************************************************/

void netdev_iob_release(FAR struct net_driver_s *dev);

#endif /* __INCLUDE_NUTTX_NET_NETDEV_H */
