266 lines
11 KiB
C
266 lines
11 KiB
C
|
/*
|
||
|
|
LUFA Library
|
||
|
|
Copyright (C) Dean Camera, 2017.
|
||
|
|
|
||
|
|
dean [at] fourwalledcubicle [dot] com
|
||
|
|
www.lufa-lib.org
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
Copyright 2017 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 disclaims 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/** \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"
|
||
|
|
|
||
|
|
#if defined(ENABLE_DHCP_SERVER) || defined(__DOXYGEN__)
|
||
|
|
|
||
|
|
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;
|
||
|
|
|
||
|
|
/* Only process when new data arrives - don't retransmit lost packets */
|
||
|
|
if (uip_newdata())
|
||
|
|
{
|
||
|
|
/* Get the DHCP message type (if present), otherwise early-abort */
|
||
|
|
uint8_t DHCPMessageType;
|
||
|
|
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &DHCPMessageType)))
|
||
|
|
return;
|
||
|
|
|
||
|
|
uip_ipaddr_t Netmask, GatewayIPAddress, PreferredClientIP;
|
||
|
|
struct uip_eth_addr RemoteMACAddress;
|
||
|
|
uint32_t TransactionID;
|
||
|
|
|
||
|
|
/* Get configured network mask, gateway IP and extract out DHCP transaction ID and remote IP */
|
||
|
|
uip_getnetmask(&Netmask);
|
||
|
|
uip_getdraddr(&GatewayIPAddress);
|
||
|
|
memcpy(&RemoteMACAddress, &AppData->ClientHardwareAddress, sizeof(struct uip_eth_addr));
|
||
|
|
TransactionID = AppData->TransactionID;
|
||
|
|
|
||
|
|
/* Try to extract out the client's preferred IP address if it is indicated in the packet */
|
||
|
|
if (!(DHCPCommon_GetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, &PreferredClientIP)))
|
||
|
|
memcpy(&PreferredClientIP, &uip_all_zeroes_addr, sizeof(uip_ipaddr_t));
|
||
|
|
|
||
|
|
switch (DHCPMessageType)
|
||
|
|
{
|
||
|
|
case DHCP_DISCOVER:
|
||
|
|
/* If no preference was made or the preferred IP is already taken, find a new address */
|
||
|
|
if (DHCPServerApp_CheckIfIPLeased(&PreferredClientIP))
|
||
|
|
DHCPServerApp_GetUnleasedIP(&PreferredClientIP);
|
||
|
|
|
||
|
|
/* Create a new DHCP OFFER packet with the offered IP address */
|
||
|
|
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_OFFER, &RemoteMACAddress, &PreferredClientIP, TransactionID);
|
||
|
|
|
||
|
|
/* Add network mask and router information to the list of DHCP OFFER packet options */
|
||
|
|
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:
|
||
|
|
/* Check to see if the requested IP address has already been leased to a client */
|
||
|
|
if (!(DHCPServerApp_CheckIfIPLeased(&PreferredClientIP)))
|
||
|
|
{
|
||
|
|
/* Create a new DHCP ACK packet to accept the IP address lease */
|
||
|
|
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_ACK, &RemoteMACAddress, &PreferredClientIP, TransactionID);
|
||
|
|
|
||
|
|
/* Add network mask and router information to the list of DHCP ACK packet options */
|
||
|
|
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);
|
||
|
|
|
||
|
|
/* Mark the requested IP as leased to a client */
|
||
|
|
DHCPServerApp_LeaseIP(&PreferredClientIP);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* Create a new DHCP NAK packet to reject the requested allocation */
|
||
|
|
AppDataSize += DHCPServerApp_FillDHCPHeader(AppData, DHCP_NAK, &RemoteMACAddress, &uip_all_zeroes_addr, 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] PreferredClientIP Preferred IP that should be given to the client if it is unallocated
|
||
|
|
* \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,
|
||
|
|
const struct uip_eth_addr* const ClientHardwareAddress,
|
||
|
|
const uip_ipaddr_t* const PreferredClientIP,
|
||
|
|
const 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));
|
||
|
|
memcpy(&DHCPHeader->YourIP, PreferredClientIP, sizeof(uip_ipaddr_t));
|
||
|
|
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 \c true if the IP has already been leased to a client, \c false otherwise.
|
||
|
|
*/
|
||
|
|
static bool DHCPServerApp_CheckIfIPLeased(const uip_ipaddr_t* const IPAddress)
|
||
|
|
{
|
||
|
|
uint8_t Byte = (IPAddress->u8[3] / 8);
|
||
|
|
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
|
||
|
|
|
||
|
|
/* Make sure that the requested IP address isn't already leased to the virtual server or another client */
|
||
|
|
if (IPAddress->u8[3] && !(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* const NewIPAddress)
|
||
|
|
{
|
||
|
|
uip_ipaddr_copy(NewIPAddress, &uip_hostaddr);
|
||
|
|
|
||
|
|
/** Look through the current subnet, skipping the broadcast and zero IP addresses */
|
||
|
|
for (uint8_t IP = 1; IP < 254; IP++)
|
||
|
|
{
|
||
|
|
/* Update new IP address to lease with the current IP address to test */
|
||
|
|
NewIPAddress->u8[3] = IP;
|
||
|
|
|
||
|
|
/* If we've found an unleased IP, abort with the updated IP stored for the called */
|
||
|
|
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(const uip_ipaddr_t* const IPAddress)
|
||
|
|
{
|
||
|
|
uint8_t Byte = (IPAddress->u8[3] / 8);
|
||
|
|
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
|
||
|
|
|
||
|
|
/* Mark the IP address as leased in the allocation table */
|
||
|
|
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(const uip_ipaddr_t* const IPAddress)
|
||
|
|
{
|
||
|
|
uint8_t Byte = (IPAddress->u8[3] / 8);
|
||
|
|
uint8_t Mask = (1 << (IPAddress->u8[3] % 8));
|
||
|
|
|
||
|
|
/* Mark the IP address as unleased in the allocation table */
|
||
|
|
LeasedIPs[Byte] &= ~Mask;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|