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incubator-nuttx/include/nuttx/net/arp.h

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/****************************************************************************
* include/nuttx/net/arp.h
* Macros and definitions for the ARP module.
*
* Copyright (C) 2007, 2009-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Derived from uIP with has a similar BSD-styple license:
*
* Author: Adam Dunkels <adam@dunkels.com>
* 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. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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_ARP_H
#define __INCLUDE_NUTTX_NET_ARP_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <stdint.h>
#include <netinet/in.h>
#include <net/ethernet.h>
#include <nuttx/net/netconfig.h>
/****************************************************************************
* Pre-Processor Definitions
****************************************************************************/
/* Recognized values of the type bytes in the Ethernet header */
#define ETHTYPE_ARP 0x0806 /* Address resolution protocol */
#define ETHTYPE_IP 0x0800 /* IP protocol */
#define ETHTYPE_IP6 0x86dd /* IP protocol version 6 */
/* Size of the Ethernet header */
#define ETH_HDRLEN 14 /* Minimum size: 2*6 + 2 */
/****************************************************************************
* Public Types
****************************************************************************/
/* The Ethernet header -- 14 bytes. The first two fields are type 'struct
* ether_addr but are represented as a simple byte array here because
* some compilers refuse to pack 6 byte structures.
*/
struct eth_hdr_s
{
uint8_t dest[6]; /* Ethernet destination address (6 bytes) */
uint8_t src[6]; /* Ethernet source address (6 bytes) */
uint16_t type; /* Type code (2 bytes) */
};
/* One entry in the ARP table (volatile!) */
struct arp_entry
{
in_addr_t at_ipaddr; /* IP address */
struct ether_addr at_ethaddr; /* Hardware address */
uint8_t at_time;
};
/****************************************************************************
* Public Data
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef CONFIG_NET_ARP
/****************************************************************************
* Name: arp_ipin
*
* Description:
* The arp_ipin() function should be called by Ethernet device drivers
* whenever an IP packet arrives from the network. The function will
* check if the address is in the ARP cache, and if so the ARP cache entry
* will be refreshed. If no ARP cache entry was found, a new one is created.
*
* This function expects that an IP packet with an Ethernet header is
* present in the d_buf buffer and that the length of the packet is in the
* d_len field.
*
****************************************************************************/
#ifdef CONFIG_NET_ARP_IPIN
void arp_ipin(struct net_driver_s *dev);
#else
# define arp_ipin(dev)
#endif
/****************************************************************************
* Name: arp_arpin
*
* Description:
* This function should be called by the Ethernet device driver when an ARP
* packet has been received. The function will act differently
* depending on the ARP packet type: if it is a reply for a request
* that we previously sent out, the ARP cache will be filled in with
* the values from the ARP reply. If the incoming ARP packet is an ARP
* request for our IP address, an ARP reply packet is created and put
* into the d_buf[] buffer.
*
* On entry, this function expects that an ARP packet with a prepended
* Ethernet header is present in the d_buf[] buffer and that the length of
* the packet is set in the d_len field.
*
* When the function returns, the value of the field d_len indicates whether
* the device driver should send out the ARP reply packet or not. If d_len
* is zero, no packet should be sent; If d_len is non-zero, it contains the
* length of the outbound packet that is present in the d_buf[] buffer.
*
****************************************************************************/
void arp_arpin(struct net_driver_s *dev);
/****************************************************************************
* Name: arp_out
*
* Description:
* This function should be called before sending out an IP packet. The
* function checks the destination IP address of the IP packet to see
* what Ethernet MAC address that should be used as a destination MAC
* address on the Ethernet.
*
* If the destination IP address is in the local network (determined
* by logical ANDing of netmask and our IP address), the function
* checks the ARP cache to see if an entry for the destination IP
* address is found. If so, an Ethernet header is pre-pended at the
* beginning of the packet and the function returns.
*
* If no ARP cache entry is found for the destination IP address, the
* packet in the d_buf[] is replaced by an ARP request packet for the
* IP address. The IP 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 Ethernet
* frame that should be transmitted.
*
****************************************************************************/
void arp_out(FAR struct net_driver_s *dev);
#else /* CONFIG_NET_ARP */
/* If ARP is disabled, stub out all ARP interfaces */
# define arp_ipin(dev)
# define arp_arpin(dev)
# define arp_out(dev)
#endif /* CONFIG_NET_ARP */
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __INCLUDE_NUTTX_NET_ARP_H */
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