dhcp_server.h

/**
 * @file dhcp_server.h
 * @brief DHCP server (Dynamic Host Configuration Protocol)
 *
 * @section License
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Copyright (C) 2010-2025 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.
 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.5.0
 **/

#ifndef _DHCP_SERVER_H
#define _DHCP_SERVER_H

//Dependencies
#include "core/net.h"

//DHCP server support
#ifndef DHCP_SERVER_SUPPORT
   #define DHCP_SERVER_SUPPORT DISABLED
#elif (DHCP_SERVER_SUPPORT != ENABLED && DHCP_SERVER_SUPPORT != DISABLED)
   #error DHCP_SERVER_SUPPORT parameter is not valid
#endif

//DHCP server tick interval
#ifndef DHCP_SERVER_TICK_INTERVAL
   #define DHCP_SERVER_TICK_INTERVAL 1000
#elif (DHCP_SERVER_TICK_INTERVAL < 10)
   #error DHCP_SERVER_TICK_INTERVAL parameter is not valid
#endif

//Maximum number of clients
#ifndef DHCP_SERVER_MAX_CLIENTS
   #define DHCP_SERVER_MAX_CLIENTS 16
#elif (DHCP_SERVER_MAX_CLIENTS < 1)
   #error DHCP_SERVER_MAX_CLIENTS parameter is not valid
#endif

//Default lease time, in seconds
#ifndef DHCP_SERVER_DEFAULT_LEASE_TIME
   #define DHCP_SERVER_DEFAULT_LEASE_TIME 86400
#elif (DHCP_SERVER_DEFAULT_LEASE_TIME < 1)
   #error DHCP_SERVER_DEFAULT_LEASE_TIME parameter is not valid
#endif

//Maximum number of DNS servers
#ifndef DHCP_SERVER_MAX_DNS_SERVERS
   #define DHCP_SERVER_MAX_DNS_SERVERS 2
#elif (DHCP_SERVER_MAX_DNS_SERVERS < 1)
   #error DHCP_SERVER_MAX_DNS_SERVERS parameter is not valid
#endif

//Application specific context
#ifndef DHCP_SERVER_PRIVATE_CONTEXT
   #define DHCP_SERVER_PRIVATE_CONTEXT
#endif

//Forward declaration of DhcpServerContext structure
struct _DhcpServerContext;
#define DhcpServerContext struct _DhcpServerContext

//C++ guard
#ifdef __cplusplus
extern "C" {
#endif


/**
 * @brief Add DHCP options callback
 **/

typedef void (*DhcpServerAddOptionsCallback)(DhcpServerContext *context,
   DhcpMessage *message, size_t *length, DhcpMessageType type);


/**
 * @brief Parse DHCP options callback
 **/

typedef error_t (*DhcpServerParseOptionsCallback)(DhcpServerContext *context,
   const DhcpMessage *message, size_t length, DhcpMessageType type);


/**
 * @brief DHCP binding
 *
 * A binding is a collection of configuration parameters associated
 * with a DHCP client
 *
 **/

typedef struct
{
   MacAddr macAddr;     ///<Client's MAC address
   Ipv4Addr ipAddr;     ///<Client's IPv4 address
   bool_t validLease;   ///<Valid lease
   systime_t timestamp; ///<Timestamp
} DhcpServerBinding;


/**
 * @brief DHCP server settings
 **/

typedef struct
{
   NetInterface *interface;                             ///<Underlying network interface
   uint_t ipAddrIndex;                                  ///<Index of the IP address assigned to the DHCP server
   bool_t rapidCommit;                                  ///<Quick configuration using rapid commit
   uint32_t leaseTime;                                  ///<Lease time, in seconds, assigned to the DHCP clients
   Ipv4Addr ipAddrRangeMin;                             ///<Lowest IP address in the pool that is available for dynamic address assignment
   Ipv4Addr ipAddrRangeMax;                             ///<Highest IP address in the pool that is available for dynamic address assignment
   Ipv4Addr subnetMask;                                 ///<Subnet mask
   Ipv4Addr defaultGateway;                             ///<Default gateway
   Ipv4Addr dnsServer[DHCP_SERVER_MAX_DNS_SERVERS];     ///<DNS servers
   DhcpServerAddOptionsCallback addOptionsCallback;     ///<Add DHCP options callback
   DhcpServerParseOptionsCallback parseOptionsCallback; ///<Parse DHCP options callback
} DhcpServerSettings;


/**
 * @brief DHCP server context
 **/

struct _DhcpServerContext
{
   DhcpServerSettings settings;                              ///<DHCP server settings
   bool_t running;                                           ///<This flag tells whether the DHCP server is running or not
   Ipv4Addr nextIpAddr;                                      ///<Next IP address to be assigned
   DhcpServerBinding clientBinding[DHCP_SERVER_MAX_CLIENTS]; ///<List of bindings
   DHCP_SERVER_PRIVATE_CONTEXT                               ///<Application specific context
};


//DHCP server related functions
void dhcpServerGetDefaultSettings(DhcpServerSettings *settings);

error_t dhcpServerInit(DhcpServerContext *context,
   const DhcpServerSettings *settings);

error_t dhcpServerStart(DhcpServerContext *context);
error_t dhcpServerStop(DhcpServerContext *context);

void dhcpServerDeinit(DhcpServerContext *context);

//C++ guard
#ifdef __cplusplus
}
#endif

#endif