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/*
LUFA Library
Copyright (C) Dean Camera, 2011.
dean [at] fourwalledcubicle [dot] com
www.lufa-lib.org
*/
/*
Copyright 2011 Dean Camera (dean [at] fourwalledcubicle [dot] com)
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby granted
without fee, provided that the above copyright notice appear in
all copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the name of the author not be used in
advertising or publicity pertaining to distribution of the
software without specific, written prior permission.
The author disclaim all warranties with regard to this
software, including all implied warranties of merchantability
and fitness. In no event shall the author be liable for any
special, indirect or consequential damages or any damages
whatsoever resulting from loss of use, data or profits, whether
in an action of contract, negligence or other tortious action,
arising out of or in connection with the use or performance of
this software.
*/
#if defined(ENABLE_DHCP_SERVER) || defined(__DOXYGEN__)
/** \file
*
* DHCP Server Application. When connected to the uIP stack, this will send IP configuration settings to a
* DHCP client on the network.
*/
#define INCLUDE_FROM_DHCPSERVERAPP_C
#include "DHCPServerApp.h"
struct uip_conn* BroadcastConnection;
uint8_t LeasedIPs[255 / 8];
/** Initialization function for the DHCP server. */
void DHCPServerApp_Init(void)
{
/* Listen on port 67 for DHCP server connections from hosts */
uip_listen(HTONS(DHCP_SERVER_PORT));
/* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
struct uip_udp_conn* BroadcastConnection = uip_udp_new(&uip_broadcast_addr, HTONS(DHCP_CLIENT_PORT));
/* If the connection was successfully created, bind it to the local DHCP client port */
if (BroadcastConnection != NULL)
uip_udp_bind(BroadcastConnection, HTONS(DHCP_SERVER_PORT));
/* Set all IP addresses as unleased */
memset(LeasedIPs, 0x00, sizeof(LeasedIPs));
}
/** uIP stack application callback for the DHCP server. This function must be called each time the TCP/IP stack
* needs a UDP packet to be processed.
*/
void DHCPServerApp_Callback(void)
{
DHCP_Header_t* const AppData = (DHCP_Header_t*)uip_appdata;
uint16_t AppDataSize = 0;
uint8_t DHCPMessageType;
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
return;
uip_ipaddr_t Netmask, GatewayIPAddress;
struct uip_eth_addr RemoteMACAddress;
uint32_t TransactionID;
memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
uip_getnetmask(&Netmask);
uip_getdraddr(&GatewayIPAddress);
TransactionID = AppData->TransactionID;
switch (DHCPMessageType)
{
case DHCP_DISCOVER:
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, TransactionID);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
sizeof(uip_ipaddr_t), &Netmask);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
sizeof(uip_ipaddr_t), &GatewayIPAddress);
/* Send the DHCP OFFER packet */
uip_poll_conn(BroadcastConnection);
memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
uip_udp_send(AppDataSize);
break;
case DHCP_REQUEST:
if (!(DHCPServerApp_CheckIfIPLeased(&AppData->YourIP)))
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &RemoteMACAddress, TransactionID);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK,
sizeof(uip_ipaddr_t), &Netmask);
AppDataSize += DHCPCommon_SetOption(AppData->Options, DHCP_OPTION_ROUTER,
sizeof(uip_ipaddr_t), &GatewayIPAddress);
DHCPServerApp_LeaseIP(&AppData->YourIP);
}
else
{
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, TransactionID);
}
/* Send the DHCP ACK or NAK packet */
uip_poll_conn(BroadcastConnection);
memcpy(&uip_udp_conn->ripaddr, &uip_broadcast_addr, sizeof(uip_ipaddr_t));
uip_udp_send(AppDataSize);
break;
case DHCP_RELEASE:
/* Mark the IP address as released in the allocation table */
DHCPServerApp_UnleaseIP(&uip_udp_conn->ripaddr);
break;
}
}
/** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
* fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP client.
*
* \param[out] DHCPHeader Location in the packet buffer where the BOOTP header should be written to
* \param[in] DHCPMessageType DHCP Message type, such as DHCP_DISCOVER
* \param[in] ClientHardwareAddress Client MAC address the created transaction should be directed to
* \param[in] TransactionID Transaction ID the created transaction should be associated with
*
* \return Size in bytes of the created DHCP packet
*/
static uint16_t DHCPServerApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader,
const uint8_t DHCPMessageType,
struct uip_eth_addr* ClientHardwareAddress,
uint32_t TransactionID)
{
/* Erase existing packet data so that we start will all 0x00 DHCP header data */
memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
DHCPHeader->Operation = DHCPMessageType;
DHCPHeader->HardwareType = DHCP_HTYPE_ETHERNET;
DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
DHCPHeader->Hops = 0;
DHCPHeader->TransactionID = TransactionID;
DHCPHeader->ElapsedSeconds = 0;
DHCPHeader->Flags = 0;
memcpy(&DHCPHeader->NextServerIP, &uip_hostaddr, sizeof(uip_ipaddr_t));
if (uip_ipaddr_cmp(&DHCPHeader->YourIP, &uip_all_zeroes_addr))
DHCPServerApp_GetUnleasedIP(&DHCPHeader->YourIP);
memcpy(&DHCPHeader->ClientHardwareAddress, ClientHardwareAddress, sizeof(struct uip_eth_addr));
DHCPHeader->Cookie = DHCP_MAGIC_COOKIE;
/* Add a DHCP message type and terminator options to the start of the DHCP options field */
DHCPHeader->Options[0] = DHCP_OPTION_MSG_TYPE;
DHCPHeader->Options[1] = 1;
DHCPHeader->Options[2] = DHCPMessageType;
DHCPHeader->Options[3] = DHCP_OPTION_END;
/* Calculate the total number of bytes added to the outgoing packet */
return (sizeof(DHCP_Header_t) + 4);
}
/** Checks to see if the nominated IP address has already been allocated to a client.
*
* \param[in] IPAddress IP Address whose lease status should be checked
*
* \pre The IP address must be within the same /24 subnet as the virtual webserver.
*
* \return Boolean true if the IP has already been leased to a client, false otherwise.
*/
static bool DHCPServerApp_CheckIfIPLeased(uip_ipaddr_t* IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
if (!(IPAddress->u8[3] == uip_hostaddr.u8[3]) && !(LeasedIPs[Byte] & Mask))
return false;
else
return true;
}
/** Retrieves the next unleased IP in the IP address pool.
*
* \param[out] NewIPAddress Location where the generated IP Address should be stored
*/
static void DHCPServerApp_GetUnleasedIP(uip_ipaddr_t* NewIPAddress)
{
uip_ipaddr_copy(NewIPAddress, &uip_hostaddr);
for (uint8_t IP = 1; IP < 254; IP++)
{
NewIPAddress->u8[3] = IP;
if (!(DHCPServerApp_CheckIfIPLeased(NewIPAddress)))
return;
}
}
/** Marks the given IP Address as leased in the address pool, so that it will not be
* allocated to another client unless it is first released.
*
* \param[in] IPAddress IP Address to mark as leased
*
* \pre The IP address must be within the same /24 subnet as the virtual webserver.
*/
static void DHCPServerApp_LeaseIP(uip_ipaddr_t* IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
LeasedIPs[Byte] |= Mask;
}
/** Marks the given IP Address as not leased in the address pool, so that it can be
* allocated to another client upon request.
*
* \param[in] IPAddress IP Address to mark as not leased
*
* \pre The IP address must be within the same /24 subnet as the virtual webserver.
*/
static void DHCPServerApp_UnleaseIP(uip_ipaddr_t* IPAddress)
{
uint8_t Byte = (IPAddress->u8[3] / 8);
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
LeasedIPs[Byte] &= ~Mask;
}
#endif
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