Projects/Webserver/Lib/DHCPApp.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  DHCP Client Application. When connected to the uIP stack, this will retrieve IP configuration settings from the
  34  *  DHCP server on the network.
  35  */
  36
  37 #include "DHCPApp.h"
  38
  39 #if defined(ENABLE_DHCP)
  40 /** Timer for managing the timeout period for a DHCP server to respond */
  41 struct timer DHCPTimer;
  42
  43 /** Initialization function for the DHCP client. */
  44 void DHCPApp_Init(void)
  45 {
  46         uip_udp_appstate_t* const AppState = &uip_udp_conn->appstate;
  47
  48         /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
  49         uip_ipaddr_t DHCPServerIPAddress;
  50         uip_ipaddr(&DHCPServerIPAddress, 255, 255, 255, 255);
  51         AppState->Connection = uip_udp_new(&DHCPServerIPAddress, HTONS(DHCPC_SERVER_PORT));
  52
  53         /* If the connection was sucessfully created, bind it to the local DHCP client port */
  54         if(AppState->Connection != NULL)
  55         {
  56                 uip_udp_bind(AppState->Connection, HTONS(DHCPC_CLIENT_PORT));
  57                 AppState->CurrentState = DHCP_STATE_SendDiscover;
  58         }
  59
  60         /* Set timeout period to half a second for a DHCP server to respond */
  61         timer_set(&DHCPTimer, CLOCK_SECOND / 2);
  62 }
  63
  64 /** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack
  65  *  needs a UDP packet to be processed.
  66  */
  67 void DHCPApp_Callback(void)
  68 {
  69         uip_udp_appstate_t* const AppState    = &uip_udp_conn->appstate;
  70         DHCP_Header_t*      const AppData     = (DHCP_Header_t*)uip_appdata;
  71         uint16_t                  AppDataSize = 0;
  72
  73         switch (AppState->CurrentState)
  74         {
  75                 case DHCP_STATE_SendDiscover:
  76                         /* Clear all DHCP settings, reset client IP address */
  77                         memset(&AppState->DHCPOffer_Data, 0x00, sizeof(AppState->DHCPOffer_Data));
  78                         uip_sethostaddr(&AppState->DHCPOffer_Data.AllocatedIP);
  79
  80                         /* Fill out the DHCP response header */
  81                         AppDataSize += DHCPApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState);
  82
  83                         /* Add the required DHCP options list to the packet */
  84                         uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER};
  85                         AppDataSize += DHCPApp_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList),
  86                                                          RequiredOptionList);
  87
  88                         /* Send the DHCP DISCOVER packet */
  89                         uip_send(AppData, AppDataSize);
  90
  91                         /* Reset the timeout timer, progress to next state */
  92                         timer_reset(&DHCPTimer);
  93                         AppState->CurrentState = DHCP_STATE_WaitForResponse;
  94
  95                         break;
  96                 case DHCP_STATE_WaitForResponse:
  97                         if (!(uip_newdata()))
  98                         {
  99                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 100                                 if (timer_expired(&DHCPTimer))
 101                                   AppState->CurrentState = DHCP_STATE_SendDiscover;
 102
 103                                 break;
 104                         }
 105
 106                         uint8_t OfferResponse_MessageType;
 107                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 108                             DHCPApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) &&
 109                             (OfferResponse_MessageType == DHCP_OFFER))
 110                         {
 111                                 /* Received a DHCP offer for an IP address, copy over values for later request */
 112                                 memcpy(&AppState->DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t));
 113                                 DHCPApp_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPOffer_Data.Netmask);
 114                                 DHCPApp_GetOption(AppData->Options, DHCP_OPTION_ROUTER,      &AppState->DHCPOffer_Data.GatewayIP);
 115                                 DHCPApp_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID,   &AppState->DHCPOffer_Data.ServerIP);
 116
 117                                 timer_reset(&DHCPTimer);
 118                                 AppState->CurrentState = DHCP_STATE_SendRequest;
 119                         }
 120
 121                         break;
 122                 case DHCP_STATE_SendRequest:
 123                         /* Fill out the DHCP response header */
 124                         AppDataSize += DHCPApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState);
 125
 126                         /* Add the DHCP REQUESTED IP ADDRESS option to the packet */
 127                         AppDataSize += DHCPApp_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t),
 128                                                          &AppState->DHCPOffer_Data.AllocatedIP);
 129
 130                         /* Add the DHCP SERVER IP ADDRESS option to the packet */
 131                         AppDataSize += DHCPApp_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t),
 132                                                          &AppState->DHCPOffer_Data.ServerIP);
 133
 134                         /* Send the DHCP REQUEST packet */
 135                         uip_send(AppData, AppDataSize);
 136
 137                         /* Reset the timeout timer, progress to next state */
 138                         timer_reset(&DHCPTimer);
 139                         AppState->CurrentState = DHCP_STATE_WaitForACK;
 140
 141                         break;
 142                 case DHCP_STATE_WaitForACK:
 143                         if (!(uip_newdata()))
 144                         {
 145                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 146                                 if (timer_expired(&DHCPTimer))
 147                                   AppState->CurrentState = DHCP_STATE_SendDiscover;
 148
 149                                 break;
 150                         }
 151
 152                         uint8_t RequestResponse_MessageType;
 153                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 154                             DHCPApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) &&
 155                             (RequestResponse_MessageType == DHCP_ACK))
 156                         {
 157                                 /* Set the new network parameters from the DHCP server */
 158                                 uip_sethostaddr(&AppState->DHCPOffer_Data.AllocatedIP);
 159                                 uip_setnetmask(&AppState->DHCPOffer_Data.Netmask);
 160                                 uip_setdraddr(&AppState->DHCPOffer_Data.GatewayIP);
 161
 162                                 AppState->CurrentState = DHCP_STATE_AddressLeased;
 163                         }
 164
 165                         break;
 166         }
 167 }
 168
 169 uint16_t DHCPApp_FillDHCPHeader(DHCP_Header_t* DHCPHeader, uint8_t DHCPMessageType, uip_udp_appstate_t* AppState)
 170 {
 171         /* Erase existing packet data so that we start will all 0x00 DHCP header data */
 172         memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
 173
 174         /* Fill out the DHCP packet header */
 175         DHCPHeader->Operation             = DHCP_OP_BOOTREQUEST;
 176         DHCPHeader->HardwareType          = DHCP_HTYPE_ETHERNET;
 177         DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
 178         DHCPHeader->Hops                  = 0;
 179         DHCPHeader->TransactionID         = DHCP_TRANSACTION_ID;
 180         DHCPHeader->ElapsedSeconds        = 0;
 181         DHCPHeader->Flags                 = HTONS(BOOTP_BROADCAST);
 182         memcpy(&DHCPHeader->ClientIP, &uip_hostaddr, sizeof(uip_ipaddr_t));
 183         memcpy(&DHCPHeader->YourIP, &AppState->DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t));
 184         memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPOffer_Data.ServerIP, sizeof(uip_ipaddr_t));
 185         memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr));
 186         DHCPHeader->Cookie                = DHCP_MAGIC_COOKIE;
 187
 188         /* Add a DHCP type and terminator options to the start of the DHCP options field */
 189         DHCPHeader->Options[0]            = DHCP_OPTION_MSG_TYPE;
 190         DHCPHeader->Options[1]            = 1;
 191         DHCPHeader->Options[2]            = DHCPMessageType;
 192         DHCPHeader->Options[3]            = DHCP_OPTION_END;
 193
 194         /* Calculate the total number of bytes added to the outgoing packet */
 195         return (sizeof(DHCP_Header_t) + 4);
 196 }
 197
 198 uint8_t DHCPApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* Source)
 199 {
 200         /* Skip through the DHCP options list until the terminator option is found */
 201         while (*DHCPOptionList != DHCP_OPTION_END)
 202           DHCPOptionList += (DHCPOptionList[1] + 2);
 203
 204         /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
 205         DHCPOptionList[0] = Option;
 206         DHCPOptionList[1] = DataLen;
 207         memcpy(&DHCPOptionList[2], Source, DataLen);
 208         DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
 209
 210         /* Calculate the total number of bytes added to the outgoing packet */
 211         return (2 + DataLen);
 212 }
 213
 214 bool DHCPApp_GetOption(uint8_t* DHCPOptionList, uint8_t Option, void* Destination)
 215 {
 216         /* Look through the incomming DHCP packet's options list for the requested option */
 217         while (*DHCPOptionList != DHCP_OPTION_END)
 218         {
 219                 /* Check if the current DHCP option in the packet is the one requested */
 220                 if (DHCPOptionList[0] == Option)
 221                 {
 222                         /* Copy request option's data to the destination buffer */
 223                         memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
 224
 225                         /* Indicate that the requested option data was sucessfully retrieved */
 226                         return true;
 227                 }
 228
 229                 /* Skip to next DHCP option in the options list */
 230                 DHCPOptionList += (DHCPOptionList[1] + 2);
 231         }
 232
 233         /* Requested option not found in the incomming packet's DHCP options list */
 234         return false;
 235 }
 236
 237 #endif