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
  41 /** Initialization function for the DHCP client. */
  42 void DHCPClientApp_Init(void)
  43 {
  44         /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
  45         struct uip_udp_conn* Connection = uip_udp_new(&uip_broadcast_addr, HTONS(DHCPC_SERVER_PORT));
  46
  47         /* If the connection was successfully created, bind it to the local DHCP client port */
  48         if (Connection != NULL)
  49         {
  50                 uip_udp_appstate_t* const AppState = &Connection->appstate;
  51                 uip_udp_bind(Connection, HTONS(DHCPC_CLIENT_PORT));
  52
  53                 /* Set the initial client state */
  54                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
  55
  56                 /* Set timeout period to half a second for a DHCP server to respond */
  57                 timer_set(&AppState->DHCPClient.Timeout, CLOCK_SECOND / 2);
  58         }
  59 }
  60
  61 /** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack
  62  *  needs a UDP packet to be processed.
  63  */
  64 void DHCPClientApp_Callback(void)
  65 {
  66         uip_udp_appstate_t* const AppState    = &uip_udp_conn->appstate;
  67         DHCP_Header_t*      const AppData     = (DHCP_Header_t*)uip_appdata;
  68         uint16_t                  AppDataSize = 0;
  69
  70         switch (AppState->DHCPClient.CurrentState)
  71         {
  72                 case DHCP_STATE_SendDiscover:
  73                         /* Clear all DHCP settings, reset client IP address */
  74                         memset(&AppState->DHCPClient.DHCPOffer_Data, 0x00, sizeof(AppState->DHCPClient.DHCPOffer_Data));
  75                         uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
  76
  77                         /* Fill out the DHCP response header */
  78                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState);
  79
  80                         /* Add the required DHCP options list to the packet */
  81                         uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER};
  82                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList),
  83                                                                RequiredOptionList);
  84
  85                         /* Send the DHCP DISCOVER packet */
  86                         uip_udp_send(AppDataSize);
  87
  88                         /* Reset the timeout timer, progress to next state */
  89                         timer_reset(&AppState->DHCPClient.Timeout);
  90                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForOffer;
  91
  92                         break;
  93                 case DHCP_STATE_WaitForOffer:
  94                         if (!(uip_newdata()))
  95                         {
  96                                 /* Check if the DHCP timeout period has expired while waiting for a response */
  97                                 if (timer_expired(&AppState->DHCPClient.Timeout))
  98                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
  99
 100                                 break;
 101                         }
 102
 103                         uint8_t OfferResponse_MessageType;
 104                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 105                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) &&
 106                             (OfferResponse_MessageType == DHCP_OFFER))
 107                         {
 108                                 /* Received a DHCP offer for an IP address, copy over values for later request */
 109                                 memcpy(&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t));
 110                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPClient.DHCPOffer_Data.Netmask);
 111                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_ROUTER,      &AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 112                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID,   &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 113
 114                                 timer_reset(&AppState->DHCPClient.Timeout);
 115                                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendRequest;
 116                         }
 117
 118                         break;
 119                 case DHCP_STATE_SendRequest:
 120                         /* Fill out the DHCP response header */
 121                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState);
 122
 123                         /* Add the DHCP REQUESTED IP ADDRESS option to the packet */
 124                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t),
 125                                                                &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 126
 127                         /* Add the DHCP SERVER IP ADDRESS option to the packet */
 128                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t),
 129                                                                &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 130
 131                         /* Send the DHCP REQUEST packet */
 132                         uip_udp_send(AppDataSize);
 133
 134                         /* Reset the timeout timer, progress to next state */
 135                         timer_reset(&AppState->DHCPClient.Timeout);
 136                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForACK;
 137
 138                         break;
 139                 case DHCP_STATE_WaitForACK:
 140                         if (!(uip_newdata()))
 141                         {
 142                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 143                                 if (timer_expired(&AppState->DHCPClient.Timeout))
 144                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
 145
 146                                 break;
 147                         }
 148
 149                         uint8_t RequestResponse_MessageType;
 150                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 151                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) &&
 152                             (RequestResponse_MessageType == DHCP_ACK))
 153                         {
 154                                 /* Set the new network parameters from the DHCP server */
 155                                 uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 156                                 uip_setnetmask((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.Netmask);
 157                                 uip_setdraddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 158
 159                                 AppState->DHCPClient.CurrentState = DHCP_STATE_AddressLeased;
 160                         }
 161
 162                         break;
 163         }
 164 }
 165
 166 /** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
 167  *  fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP server.
 168  *
 169  *  \param[out] DHCPHeader  Location in the packet buffer where the BOOTP header should be written to
 170  *  \param[in]  DHCPMessageType  DHCP Message type, such as DHCP_DISCOVER
 171  *  \param[in]  AppState    Application state of the current UDP connection
 172  *
 173  *  \return Size in bytes of the created DHCP packet
 174  */
 175 uint16_t DHCPClientApp_FillDHCPHeader(DHCP_Header_t* DHCPHeader, uint8_t DHCPMessageType, uip_udp_appstate_t* AppState)
 176 {
 177         /* Erase existing packet data so that we start will all 0x00 DHCP header data */
 178         memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
 179
 180         /* Fill out the DHCP packet header */
 181         DHCPHeader->Operation             = DHCP_OP_BOOTREQUEST;
 182         DHCPHeader->HardwareType          = DHCP_HTYPE_ETHERNET;
 183         DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
 184         DHCPHeader->Hops                  = 0;
 185         DHCPHeader->TransactionID         = DHCP_TRANSACTION_ID;
 186         DHCPHeader->ElapsedSeconds        = 0;
 187         DHCPHeader->Flags                 = HTONS(BOOTP_BROADCAST);
 188         memcpy(&DHCPHeader->ClientIP,     &uip_hostaddr,        sizeof(uip_ipaddr_t));
 189         memcpy(&DHCPHeader->YourIP,       &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t));
 190         memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPClient.DHCPOffer_Data.ServerIP,    sizeof(uip_ipaddr_t));
 191         memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr));
 192         DHCPHeader->Cookie                = DHCP_MAGIC_COOKIE;
 193
 194         /* Add a DHCP message type and terminator options to the start of the DHCP options field */
 195         DHCPHeader->Options[0]            = DHCP_OPTION_MSG_TYPE;
 196         DHCPHeader->Options[1]            = 1;
 197         DHCPHeader->Options[2]            = DHCPMessageType;
 198         DHCPHeader->Options[3]            = DHCP_OPTION_END;
 199
 200         /* Calculate the total number of bytes added to the outgoing packet */
 201         return (sizeof(DHCP_Header_t) + 4);
 202 }
 203
 204 /** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the
 205  *  end of options terminator past the new option in the options list.
 206  *
 207  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 208  *  \param[in]     Option          DHCP option to add to the list
 209  *  \param[in]     DataLen         Size in bytes of the option data to add
 210  *  \param[in]     OptionData      Buffer where the option's data is to be sourced from
 211  *
 212  *  \return Number of bytes added to the DHCP packet
 213  */
 214 uint8_t DHCPClientApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* OptionData)
 215 {
 216         /* Skip through the DHCP options list until the terminator option is found */
 217         while (*DHCPOptionList != DHCP_OPTION_END)
 218           DHCPOptionList += (DHCPOptionList[1] + 2);
 219
 220         /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
 221         DHCPOptionList[0] = Option;
 222         DHCPOptionList[1] = DataLen;
 223         memcpy(&DHCPOptionList[2], OptionData, DataLen);
 224         DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
 225
 226         /* Calculate the total number of bytes added to the outgoing packet */
 227         return (2 + DataLen);
 228 }
 229
 230 /** Retrieves the given option's data (if present) from the DHCP packet's options list.
 231  *
 232  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 233  *  \param[in]     Option          DHCP option to retrieve to the list
 234  *  \param[out]    Destination     Buffer where the option's data is to be written to if found
 235  *
 236  *  \return Boolean true if the option was found in the DHCP packet's options list, false otherwise
 237  */
 238 bool DHCPClientApp_GetOption(uint8_t* DHCPOptionList, uint8_t Option, void* Destination)
 239 {
 240         /* Look through the incoming DHCP packet's options list for the requested option */
 241         while (*DHCPOptionList != DHCP_OPTION_END)
 242         {
 243                 /* Check if the current DHCP option in the packet is the one requested */
 244                 if (DHCPOptionList[0] == Option)
 245                 {
 246                         /* Copy request option's data to the destination buffer */
 247                         memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
 248
 249                         /* Indicate that the requested option data was successfully retrieved */
 250                         return true;
 251                 }
 252
 253                 /* Skip to next DHCP option in the options list */
 254                 DHCPOptionList += (DHCPOptionList[1] + 2);
 255         }
 256
 257         /* Requested option not found in the incoming packet's DHCP options list */
 258         return false;
 259 }
 260 #endif