Projects/Webserver/Lib/DHCPClientApp.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 "DHCPClientApp.h"
  38
  39 #if defined(ENABLE_DHCP_CLIENT) || 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 DHCPClientApp_Init(void)
  45 {
  46         /* Create an IP address to the broadcast network address */
  47         uip_ipaddr_t DHCPServerIPAddress;
  48         uip_ipaddr(&DHCPServerIPAddress, 255, 255, 255, 255);
  49
  50         /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
  51         struct uip_udp_conn* Connection = uip_udp_new(&DHCPServerIPAddress, HTONS(DHCPC_SERVER_PORT));
  52
  53         /* If the connection was successfully created, bind it to the local DHCP client port */
  54         if (Connection != NULL)
  55         {
  56                 uip_udp_appstate_t* const AppState = &Connection->appstate;
  57
  58                 uip_udp_bind(Connection, HTONS(DHCPC_CLIENT_PORT));
  59                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
  60         }
  61
  62         /* Set timeout period to half a second for a DHCP server to respond */
  63         timer_set(&DHCPTimer, CLOCK_SECOND / 2);
  64 }
  65
  66 /** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack
  67  *  needs a UDP packet to be processed.
  68  */
  69 void DHCPClientApp_Callback(void)
  70 {
  71         uip_udp_appstate_t* const AppState    = &uip_udp_conn->appstate;
  72         DHCP_Header_t*      const AppData     = (DHCP_Header_t*)uip_appdata;
  73         uint16_t                  AppDataSize = 0;
  74
  75         switch (AppState->DHCPClient.CurrentState)
  76         {
  77                 case DHCP_STATE_SendDiscover:
  78                         /* Clear all DHCP settings, reset client IP address */
  79                         memset(&AppState->DHCPClient.DHCPOffer_Data, 0x00, sizeof(AppState->DHCPClient.DHCPOffer_Data));
  80                         uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
  81
  82                         /* Fill out the DHCP response header */
  83                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState);
  84
  85                         /* Add the required DHCP options list to the packet */
  86                         uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER};
  87                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList),
  88                                                                RequiredOptionList);
  89
  90                         /* Send the DHCP DISCOVER packet */
  91                         uip_udp_send(AppDataSize);
  92
  93                         /* Reset the timeout timer, progress to next state */
  94                         timer_reset(&DHCPTimer);
  95                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForOffer;
  96
  97                         break;
  98                 case DHCP_STATE_WaitForOffer:
  99                         if (!(uip_newdata()))
 100                         {
 101                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 102                                 if (timer_expired(&DHCPTimer))
 103                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
 104
 105                                 break;
 106                         }
 107
 108                         uint8_t OfferResponse_MessageType;
 109                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 110                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) &&
 111                             (OfferResponse_MessageType == DHCP_OFFER))
 112                         {
 113                                 /* Received a DHCP offer for an IP address, copy over values for later request */
 114                                 memcpy(&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t));
 115                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPClient.DHCPOffer_Data.Netmask);
 116                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_ROUTER,      &AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 117                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID,   &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 118
 119                                 timer_reset(&DHCPTimer);
 120                                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendRequest;
 121                         }
 122
 123                         break;
 124                 case DHCP_STATE_SendRequest:
 125                         /* Fill out the DHCP response header */
 126                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState);
 127
 128                         /* Add the DHCP REQUESTED IP ADDRESS option to the packet */
 129                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t),
 130                                                                &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 131
 132                         /* Add the DHCP SERVER IP ADDRESS option to the packet */
 133                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t),
 134                                                                &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 135
 136                         /* Send the DHCP REQUEST packet */
 137                         uip_udp_send(AppDataSize);
 138
 139                         /* Reset the timeout timer, progress to next state */
 140                         timer_reset(&DHCPTimer);
 141                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForACK;
 142
 143                         break;
 144                 case DHCP_STATE_WaitForACK:
 145                         if (!(uip_newdata()))
 146                         {
 147                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 148                                 if (timer_expired(&DHCPTimer))
 149                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
 150
 151                                 break;
 152                         }
 153
 154                         uint8_t RequestResponse_MessageType;
 155                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 156                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) &&
 157                             (RequestResponse_MessageType == DHCP_ACK))
 158                         {
 159                                 /* Set the new network parameters from the DHCP server */
 160                                 uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 161                                 uip_setnetmask((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.Netmask);
 162                                 uip_setdraddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 163
 164                                 AppState->DHCPClient.CurrentState = DHCP_STATE_AddressLeased;
 165                         }
 166
 167                         break;
 168         }
 169 }
 170
 171 /** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
 172  *  fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP server.
 173  *
 174  *  \param[out] DHCPHeader  Location in the packet buffer where the BOOTP header should be written to
 175  *  \param[in]  DHCPMessageType  DHCP Message type, such as DHCP_DISCOVER
 176  *  \param[in]  AppState    Application state of the current UDP connection
 177  *
 178  *  \return Size in bytes of the created DHCP packet
 179  */
 180 uint16_t DHCPClientApp_FillDHCPHeader(DHCP_Header_t* DHCPHeader, uint8_t DHCPMessageType, uip_udp_appstate_t* AppState)
 181 {
 182         /* Erase existing packet data so that we start will all 0x00 DHCP header data */
 183         memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
 184
 185         /* Fill out the DHCP packet header */
 186         DHCPHeader->Operation             = DHCP_OP_BOOTREQUEST;
 187         DHCPHeader->HardwareType          = DHCP_HTYPE_ETHERNET;
 188         DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
 189         DHCPHeader->Hops                  = 0;
 190         DHCPHeader->TransactionID         = DHCP_TRANSACTION_ID;
 191         DHCPHeader->ElapsedSeconds        = 0;
 192         DHCPHeader->Flags                 = HTONS(BOOTP_BROADCAST);
 193         memcpy(&DHCPHeader->ClientIP,     &uip_hostaddr,        sizeof(uip_ipaddr_t));
 194         memcpy(&DHCPHeader->YourIP,       &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t));
 195         memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPClient.DHCPOffer_Data.ServerIP,    sizeof(uip_ipaddr_t));
 196         memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr));
 197         DHCPHeader->Cookie                = DHCP_MAGIC_COOKIE;
 198
 199         /* Add a DHCP message type and terminator options to the start of the DHCP options field */
 200         DHCPHeader->Options[0]            = DHCP_OPTION_MSG_TYPE;
 201         DHCPHeader->Options[1]            = 1;
 202         DHCPHeader->Options[2]            = DHCPMessageType;
 203         DHCPHeader->Options[3]            = DHCP_OPTION_END;
 204
 205         /* Calculate the total number of bytes added to the outgoing packet */
 206         return (sizeof(DHCP_Header_t) + 4);
 207 }
 208
 209 /** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the
 210  *  end of options terminator past the new option in the options list.
 211  *
 212  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 213  *  \param[in]     Option          DHCP option to add to the list
 214  *  \param[in]     DataLen         Size in bytes of the option data to add
 215  *  \param[in]     OptionData      Buffer where the option's data is to be sourced from
 216  *
 217  *  \return Number of bytes added to the DHCP packet
 218  */
 219 uint8_t DHCPClientApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* OptionData)
 220 {
 221         /* Skip through the DHCP options list until the terminator option is found */
 222         while (*DHCPOptionList != DHCP_OPTION_END)
 223           DHCPOptionList += (DHCPOptionList[1] + 2);
 224
 225         /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
 226         DHCPOptionList[0] = Option;
 227         DHCPOptionList[1] = DataLen;
 228         memcpy(&DHCPOptionList[2], OptionData, DataLen);
 229         DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
 230
 231         /* Calculate the total number of bytes added to the outgoing packet */
 232         return (2 + DataLen);
 233 }
 234
 235 /** Retrieves the given option's data (if present) from the DHCP packet's options list.
 236  *
 237  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 238  *  \param[in]     Option          DHCP option to retrieve to the list
 239  *  \param[out]    Destination     Buffer where the option's data is to be written to if found
 240  *
 241  *  \return Boolean true if the option was found in the DHCP packet's options list, false otherwise
 242  */
 243 bool DHCPClientApp_GetOption(uint8_t* DHCPOptionList, uint8_t Option, void* Destination)
 244 {
 245         /* Look through the incoming DHCP packet's options list for the requested option */
 246         while (*DHCPOptionList != DHCP_OPTION_END)
 247         {
 248                 /* Check if the current DHCP option in the packet is the one requested */
 249                 if (DHCPOptionList[0] == Option)
 250                 {
 251                         /* Copy request option's data to the destination buffer */
 252                         memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
 253
 254                         /* Indicate that the requested option data was successfully retrieved */
 255                         return true;
 256                 }
 257
 258                 /* Skip to next DHCP option in the options list */
 259                 DHCPOptionList += (DHCPOptionList[1] + 2);
 260         }
 261
 262         /* Requested option not found in the incoming packet's DHCP options list */
 263         return false;
 264 }
 265 #endif