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) || defined(__DOXYGEN__)
  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_udp_send(AppDataSize);
  90
  91                         /* Reset the timeout timer, progress to next state */
  92                         timer_reset(&DHCPTimer);
  93                         AppState->CurrentState = DHCP_STATE_WaitForOffer;
  94
  95                         break;
  96                 case DHCP_STATE_WaitForOffer:
  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_udp_send(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 /** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
 170  *  fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP server.
 171  *
 172  *  \param[out] DHCPHeader  Location in the packet buffer where the BOOTP header should be written to
 173  *  \param[in]  DHCPMessageType  DHCP Message type, such as DHCP_DISCOVER
 174  *  \param[in]  AppState    Application state of the current UDP connection
 175  *
 176  *  \return Size in bytes of the created DHCP packet
 177  */
 178 uint16_t DHCPApp_FillDHCPHeader(DHCP_Header_t* DHCPHeader, uint8_t DHCPMessageType, uip_udp_appstate_t* AppState)
 179 {
 180         /* Erase existing packet data so that we start will all 0x00 DHCP header data */
 181         memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
 182
 183         /* Fill out the DHCP packet header */
 184         DHCPHeader->Operation             = DHCP_OP_BOOTREQUEST;
 185         DHCPHeader->HardwareType          = DHCP_HTYPE_ETHERNET;
 186         DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
 187         DHCPHeader->Hops                  = 0;
 188         DHCPHeader->TransactionID         = DHCP_TRANSACTION_ID;
 189         DHCPHeader->ElapsedSeconds        = 0;
 190         DHCPHeader->Flags                 = HTONS(BOOTP_BROADCAST);
 191         memcpy(&DHCPHeader->ClientIP, &uip_hostaddr, sizeof(uip_ipaddr_t));
 192         memcpy(&DHCPHeader->YourIP, &AppState->DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t));
 193         memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPOffer_Data.ServerIP, sizeof(uip_ipaddr_t));
 194         memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr));
 195         DHCPHeader->Cookie                = DHCP_MAGIC_COOKIE;
 196
 197         /* Add a DHCP type and terminator options to the start of the DHCP options field */
 198         DHCPHeader->Options[0]            = DHCP_OPTION_MSG_TYPE;
 199         DHCPHeader->Options[1]            = 1;
 200         DHCPHeader->Options[2]            = DHCPMessageType;
 201         DHCPHeader->Options[3]            = DHCP_OPTION_END;
 202
 203         /* Calculate the total number of bytes added to the outgoing packet */
 204         return (sizeof(DHCP_Header_t) + 4);
 205 }
 206
 207 /** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the
 208  *  end of options terminator past the new option in the options list.
 209  *
 210  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 211  *  \param[in]     Option          DHCP option to add to the list
 212  *  \param[in]     DataLen         Size in bytes of the option data to add
 213  *  \param[in]     OptionData      Buffer where the option's data is to be sourced from
 214  *
 215  *  \return Number of bytes added to the DHCP packet
 216  */
 217 uint8_t DHCPApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* OptionData)
 218 {
 219         /* Skip through the DHCP options list until the terminator option is found */
 220         while (*DHCPOptionList != DHCP_OPTION_END)
 221           DHCPOptionList += (DHCPOptionList[1] + 2);
 222
 223         /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
 224         DHCPOptionList[0] = Option;
 225         DHCPOptionList[1] = DataLen;
 226         memcpy(&DHCPOptionList[2], OptionData, DataLen);
 227         DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
 228
 229         /* Calculate the total number of bytes added to the outgoing packet */
 230         return (2 + DataLen);
 231 }
 232
 233 /** Retrieves the given option's data (if present) from the DHCP packet's options list.
 234  *
 235  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 236  *  \param[in]     Option          DHCP option to retrieve to the list
 237  *  \param[out]    Destination     Buffer where the option's data is to be written to if found
 238  *
 239  *  \return Boolean true if the option was found in the DHCP packet's options list, false otherwise
 240  */
 241 bool DHCPApp_GetOption(uint8_t* DHCPOptionList, uint8_t Option, void* Destination)
 242 {
 243         /* Look through the incomming DHCP packet's options list for the requested option */
 244         while (*DHCPOptionList != DHCP_OPTION_END)
 245         {
 246                 /* Check if the current DHCP option in the packet is the one requested */
 247                 if (DHCPOptionList[0] == Option)
 248                 {
 249                         /* Copy request option's data to the destination buffer */
 250                         memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
 251
 252                         /* Indicate that the requested option data was sucessfully retrieved */
 253                         return true;
 254                 }
 255
 256                 /* Skip to next DHCP option in the options list */
 257                 DHCPOptionList += (DHCPOptionList[1] + 2);
 258         }
 259
 260         /* Requested option not found in the incomming packet's DHCP options list */
 261         return false;
 262 }
 263 #endif