auto_ip.c

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/**
 * @file auto_ip.c
 * @brief Auto-IP (Dynamic Configuration of IPv4 Link-Local Addresses)
 *
 * @section License
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Copyright (C) 2010-2026 Oryx Embedded SARL. All rights reserved.
 *
 * This file is part of CycloneTCP Open.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * @section Description
 *
 * Auto-IP describes a method by which a host may automatically configure an
 * interface with an IPv4 address in the 169.254/16 prefix that is valid for
 * Link-Local communication on that interface. This is especially valuable in
 * environments where no other configuration mechanism is available. Refer to
 * the following RFCs for complete details:
 * - RFC 3927: Dynamic Configuration of IPv4 Link-Local Addresses
 * - RFC 5227: IPv4 Address Conflict Detection
 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.6.0
 **/
 
//Switch to the appropriate trace level
#define TRACE_LEVEL AUTO_IP_TRACE_LEVEL
 
//Dependencies
#include "core/net.h"
#include "ipv4/auto_ip.h"
#include "ipv4/auto_ip_misc.h"
#include "debug.h"
 
//Check TCP/IP stack configuration
#if (IPV4_SUPPORT == ENABLED && AUTO_IP_SUPPORT == ENABLED)
 
 
/**
 * @brief Initialize settings with default values
 * @param[out] settings Structure that contains Auto-IP settings
 **/
 
void autoIpGetDefaultSettings(AutoIpSettings *settings)
{
   //Network interface to configure
   settings->interface = NULL;
   //Index of the IP address to be configured
   settings->ipAddrIndex = 0;
 
   //Initial link-local address to be used
   settings->linkLocalAddr = IPV4_UNSPECIFIED_ADDR;
   //Link state change event
   settings->linkChangeEvent = NULL;
   //FSM state change event
   settings->stateChangeEvent = NULL;
}
 
 
/**
 * @brief Auto-IP initialization
 * @param[in] context Pointer to the Auto-IP context
 * @param[in] settings Auto-IP specific settings
 * @return Error code
 **/
 
error_t autoIpInit(AutoIpContext *context, const AutoIpSettings *settings)
{
   NetInterface *interface;
 
   //Debug message
   TRACE_INFO("Initializing Auto-IP...\r\n");
 
   //Ensure the parameters are valid
   if(context == NULL || settings == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //The Auto-IP service must be bound to a valid interface
   if(settings->interface == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Point to the underlying network interface
   interface = settings->interface;
 
   //Clear the Auto-IP context
   osMemset(context, 0, sizeof(AutoIpContext));
 
   //Attach TCP/IP stack context
   context->netContext = settings->interface->netContext;
 
   //Save user settings
   context->interface = settings->interface;
   context->ipAddrIndex = settings->ipAddrIndex;
   context->linkChangeEvent = settings->linkChangeEvent;
   context->stateChangeEvent = settings->stateChangeEvent;
 
   //Use default link-local address
   context->linkLocalAddr = settings->linkLocalAddr;
   //Reset conflict counter
   context->conflictCount = 0;
 
   //Auto-IP operation is currently suspended
   context->running = FALSE;
   //Initialize state machine
   context->state = AUTO_IP_STATE_INIT;
 
   //Get exclusive access
   netLock(context->netContext);
   //Attach the Auto-IP context to the network interface
   interface->autoIpContext = context;
   //Release exclusive access
   netUnlock(context->netContext);
 
   //Successful initialization
   return NO_ERROR;
}
 
 
/**
 * @brief Start Auto-IP process
 * @param[in] context Pointer to the Auto-IP context
 * @return Error code
 **/
 
error_t autoIpStart(AutoIpContext *context)
{
   //Make sure the Auto-IP context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Debug message
   TRACE_INFO("Starting Auto-IP...\r\n");
 
   //Get exclusive access
   netLock(context->netContext);
 
   //Reset Auto-IP configuration
   autoIpResetConfig(context);
 
   //Initialize state machine
   context->state = AUTO_IP_STATE_INIT;
   //Reset conflict counter
   context->conflictCount = 0;
   //Start Auto-IP operation
   context->running = TRUE;
 
   //Release exclusive access
   netUnlock(context->netContext);
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Stop Auto-IP process
 * @param[in] context Pointer to the Auto-IP context
 * @return Error code
 **/
 
error_t autoIpStop(AutoIpContext *context)
{
   //Make sure the Auto-IP context is valid
   if(context == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Debug message
   TRACE_INFO("Stopping Auto-IP...\r\n");
 
   //Get exclusive access
   netLock(context->netContext);
 
   //Suspend Auto-IP operation
   context->running = FALSE;
   //Reinitialize state machine
   context->state = AUTO_IP_STATE_INIT;
 
   //Release exclusive access
   netUnlock(context->netContext);
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Retrieve current state
 * @param[in] context Pointer to the Auto-IP context
 * @return Current Auto-IP state
 **/
 
AutoIpState autoIpGetState(AutoIpContext *context)
{
   AutoIpState state;
 
   //Get exclusive access
   netLock(context->netContext);
   //Get current state
   state = context->state;
   //Release exclusive access
   netUnlock(context->netContext);
 
   //Return current state
   return state;
}
 
 
/**
 * @brief Release Auto-IP context
 * @param[in] context Pointer to the Auto-IP context
 **/
 
void autoIpDeinit(AutoIpContext *context)
{
   NetInterface *interface;
 
   //Make sure the Auto-IP context is valid
   if(context != NULL)
   {
      //Get exclusive access
      netLock(context->netContext);
 
      //Point to the underlying network interface
      interface = context->interface;
      //Detach the Auto-IP context from the network interface
      interface->autoIpContext = NULL;
 
      //Release exclusive access
      netUnlock(context->netContext);
 
      //Clear Auto-IP context
      osMemset(context, 0, sizeof(AutoIpContext));
   }
}
 
#endif