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 #if defined(ENABLE_DHCP_CLIENT) || defined(__DOXYGEN__)
  32
  33 /** \file
  34  *
  35  *  DHCP Client Application. When connected to the uIP stack, this will retrieve IP configuration settings from the
  36  *  DHCP server on the network.
  37  */
  38
  39 #define  INCLUDE_FROM_DHCPCLIENTAPP_C
  40 #include "DHCPClientApp.h"
  41
  42 /** Initialization function for the DHCP client. */
  43 void DHCPClientApp_Init(void)
  44 {
  45         /* Create a new UDP connection to the DHCP server port for the DHCP solicitation */
  46         struct uip_udp_conn* Connection = uip_udp_new(&uip_broadcast_addr, HTONS(DHCPC_SERVER_PORT));
  47
  48         /* If the connection was successfully created, bind it to the local DHCP client port */
  49         if (Connection != NULL)
  50         {
  51                 uip_udp_appstate_t* const AppState = &Connection->appstate;
  52                 uip_udp_bind(Connection, HTONS(DHCPC_CLIENT_PORT));
  53
  54                 /* Set the initial client state */
  55                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
  56
  57                 /* Set timeout period to half a second for a DHCP server to respond */
  58                 timer_set(&AppState->DHCPClient.Timeout, CLOCK_SECOND / 2);
  59         }
  60 }
  61
  62 /** uIP stack application callback for the DHCP client. This function must be called each time the TCP/IP stack
  63  *  needs a UDP packet to be processed.
  64  */
  65 void DHCPClientApp_Callback(void)
  66 {
  67         uip_udp_appstate_t* const AppState    = &uip_udp_conn->appstate;
  68         DHCP_Header_t*      const AppData     = (DHCP_Header_t*)uip_appdata;
  69         uint16_t                  AppDataSize = 0;
  70
  71         switch (AppState->DHCPClient.CurrentState)
  72         {
  73                 case DHCP_STATE_SendDiscover:
  74                         /* Clear all DHCP settings, reset client IP address */
  75                         memset(&AppState->DHCPClient.DHCPOffer_Data, 0x00, sizeof(AppState->DHCPClient.DHCPOffer_Data));
  76                         uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
  77
  78                         /* Fill out the DHCP response header */
  79                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_DISCOVER, AppState);
  80
  81                         /* Add the required DHCP options list to the packet */
  82                         uint8_t RequiredOptionList[] = {DHCP_OPTION_SUBNET_MASK, DHCP_OPTION_ROUTER, DHCP_OPTION_DNS_SERVER};
  83                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_LIST, sizeof(RequiredOptionList),
  84                                                                RequiredOptionList);
  85
  86                         /* Send the DHCP DISCOVER packet */
  87                         uip_udp_send(AppDataSize);
  88
  89                         /* Reset the timeout timer, progress to next state */
  90                         timer_reset(&AppState->DHCPClient.Timeout);
  91                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForOffer;
  92
  93                         break;
  94                 case DHCP_STATE_WaitForOffer:
  95                         if (!(uip_newdata()))
  96                         {
  97                                 /* Check if the DHCP timeout period has expired while waiting for a response */
  98                                 if (timer_expired(&AppState->DHCPClient.Timeout))
  99                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
 100
 101                                 break;
 102                         }
 103
 104                         uint8_t OfferResponse_MessageType;
 105                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 106                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &OfferResponse_MessageType) &&
 107                             (OfferResponse_MessageType == DHCP_OFFER))
 108                         {
 109                                 /* Received a DHCP offer for an IP address, copy over values for later request */
 110                                 memcpy(&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, &AppData->YourIP, sizeof(uip_ipaddr_t));
 111                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SUBNET_MASK, &AppState->DHCPClient.DHCPOffer_Data.Netmask);
 112                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_ROUTER,      &AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 113                                 DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_SERVER_ID,   &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 114
 115                                 timer_reset(&AppState->DHCPClient.Timeout);
 116                                 AppState->DHCPClient.CurrentState = DHCP_STATE_SendRequest;
 117                         }
 118
 119                         break;
 120                 case DHCP_STATE_SendRequest:
 121                         /* Fill out the DHCP response header */
 122                         AppDataSize += DHCPClientApp_FillDHCPHeader(AppData, DHCP_REQUEST, AppState);
 123
 124                         /* Add the DHCP REQUESTED IP ADDRESS option to the packet */
 125                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_REQ_IPADDR, sizeof(uip_ipaddr_t),
 126                                                                &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 127
 128                         /* Add the DHCP SERVER IP ADDRESS option to the packet */
 129                         AppDataSize += DHCPClientApp_SetOption(AppData->Options, DHCP_OPTION_SERVER_ID, sizeof(uip_ipaddr_t),
 130                                                                &AppState->DHCPClient.DHCPOffer_Data.ServerIP);
 131
 132                         /* Send the DHCP REQUEST packet */
 133                         uip_udp_send(AppDataSize);
 134
 135                         /* Reset the timeout timer, progress to next state */
 136                         timer_reset(&AppState->DHCPClient.Timeout);
 137                         AppState->DHCPClient.CurrentState = DHCP_STATE_WaitForACK;
 138
 139                         break;
 140                 case DHCP_STATE_WaitForACK:
 141                         if (!(uip_newdata()))
 142                         {
 143                                 /* Check if the DHCP timeout period has expired while waiting for a response */
 144                                 if (timer_expired(&AppState->DHCPClient.Timeout))
 145                                   AppState->DHCPClient.CurrentState = DHCP_STATE_SendDiscover;
 146
 147                                 break;
 148                         }
 149
 150                         uint8_t RequestResponse_MessageType;
 151                         if ((AppData->TransactionID == DHCP_TRANSACTION_ID) &&
 152                             DHCPClientApp_GetOption(AppData->Options, DHCP_OPTION_MSG_TYPE, &RequestResponse_MessageType) &&
 153                             (RequestResponse_MessageType == DHCP_ACK))
 154                         {
 155                                 /* Set the new network parameters from the DHCP server */
 156                                 uip_sethostaddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.AllocatedIP);
 157                                 uip_setnetmask((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.Netmask);
 158                                 uip_setdraddr((uip_ipaddr_t*)&AppState->DHCPClient.DHCPOffer_Data.GatewayIP);
 159
 160                                 /* Indicate to the user that we now have a valid IP configuration */
 161                                 HaveIPConfiguration = true;
 162
 163                                 AppState->DHCPClient.CurrentState = DHCP_STATE_AddressLeased;
 164                         }
 165
 166                         break;
 167         }
 168 }
 169
 170 /** Fills the DHCP packet response with the appropriate BOOTP header for DHCP. This fills out all the required
 171  *  fields, leaving only the additional DHCP options to be added to the packet before it is sent to the DHCP server.
 172  *
 173  *  \param[out] DHCPHeader  Location in the packet buffer where the BOOTP header should be written to
 174  *  \param[in]  DHCPMessageType  DHCP Message type, such as DHCP_DISCOVER
 175  *  \param[in]  AppState    Application state of the current UDP connection
 176  *
 177  *  \return Size in bytes of the created DHCP packet
 178  */
 179 static uint16_t DHCPClientApp_FillDHCPHeader(DHCP_Header_t* const DHCPHeader, const uint8_t DHCPMessageType, uip_udp_appstate_t* AppState)
 180 {
 181         /* Erase existing packet data so that we start will all 0x00 DHCP header data */
 182         memset(DHCPHeader, 0, sizeof(DHCP_Header_t));
 183
 184         /* Fill out the DHCP packet header */
 185         DHCPHeader->Operation             = DHCP_OP_BOOTREQUEST;
 186         DHCPHeader->HardwareType          = DHCP_HTYPE_ETHERNET;
 187         DHCPHeader->HardwareAddressLength = sizeof(MACAddress);
 188         DHCPHeader->Hops                  = 0;
 189         DHCPHeader->TransactionID         = DHCP_TRANSACTION_ID;
 190         DHCPHeader->ElapsedSeconds        = 0;
 191         DHCPHeader->Flags                 = HTONS(BOOTP_BROADCAST);
 192         memcpy(&DHCPHeader->ClientIP,     &uip_hostaddr,        sizeof(uip_ipaddr_t));
 193         memcpy(&DHCPHeader->YourIP,       &AppState->DHCPClient.DHCPOffer_Data.AllocatedIP, sizeof(uip_ipaddr_t));
 194         memcpy(&DHCPHeader->NextServerIP, &AppState->DHCPClient.DHCPOffer_Data.ServerIP,    sizeof(uip_ipaddr_t));
 195         memcpy(&DHCPHeader->ClientHardwareAddress, &MACAddress, sizeof(struct uip_eth_addr));
 196         DHCPHeader->Cookie                = DHCP_MAGIC_COOKIE;
 197
 198         /* Add a DHCP message type and terminator options to the start of the DHCP options field */
 199         DHCPHeader->Options[0]            = DHCP_OPTION_MSG_TYPE;
 200         DHCPHeader->Options[1]            = 1;
 201         DHCPHeader->Options[2]            = DHCPMessageType;
 202         DHCPHeader->Options[3]            = DHCP_OPTION_END;
 203
 204         /* Calculate the total number of bytes added to the outgoing packet */
 205         return (sizeof(DHCP_Header_t) + 4);
 206 }
 207
 208 /** Sets the given DHCP option in the DHCP packet's option list. This automatically moves the
 209  *  end of options terminator past the new option in the options list.
 210  *
 211  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 212  *  \param[in]     Option          DHCP option to add to the list
 213  *  \param[in]     DataLen         Size in bytes of the option data to add
 214  *  \param[in]     OptionData      Buffer where the option's data is to be sourced from
 215  *
 216  *  \return Number of bytes added to the DHCP packet
 217  */
 218 static uint8_t DHCPClientApp_SetOption(uint8_t* DHCPOptionList, uint8_t Option, uint8_t DataLen, void* OptionData)
 219 {
 220         /* Skip through the DHCP options list until the terminator option is found */
 221         while (*DHCPOptionList != DHCP_OPTION_END)
 222           DHCPOptionList += (DHCPOptionList[1] + 2);
 223
 224         /* Overwrite the existing terminator with the new option, add a new terminator at the end of the list */
 225         DHCPOptionList[0] = Option;
 226         DHCPOptionList[1] = DataLen;
 227         memcpy(&DHCPOptionList[2], OptionData, DataLen);
 228         DHCPOptionList[2 + DataLen] = DHCP_OPTION_END;
 229
 230         /* Calculate the total number of bytes added to the outgoing packet */
 231         return (2 + DataLen);
 232 }
 233
 234 /** Retrieves the given option's data (if present) from the DHCP packet's options list.
 235  *
 236  *  \param[in,out] DHCPOptionList  Pointer to the start of the DHCP packet's options list
 237  *  \param[in]     Option          DHCP option to retrieve to the list
 238  *  \param[out]    Destination     Buffer where the option's data is to be written to if found
 239  *
 240  *  \return Boolean true if the option was found in the DHCP packet's options list, false otherwise
 241  */
 242 static bool DHCPClientApp_GetOption(const uint8_t* DHCPOptionList, const uint8_t Option, void* const Destination)
 243 {
 244         /* Look through the incoming DHCP packet's options list for the requested option */
 245         while (*DHCPOptionList != DHCP_OPTION_END)
 246         {
 247                 /* Check if the current DHCP option in the packet is the one requested */
 248                 if (DHCPOptionList[0] == Option)
 249                 {
 250                         /* Copy request option's data to the destination buffer */
 251                         memcpy(Destination, &DHCPOptionList[2], DHCPOptionList[1]);
 252
 253                         /* Indicate that the requested option data was successfully retrieved */
 254                         return true;
 255                 }
 256
 257                 /* Skip to next DHCP option in the options list */
 258                 DHCPOptionList += (DHCPOptionList[1] + 2);
 259         }
 260
 261         /* Requested option not found in the incoming packet's DHCP options list */
 262         return false;
 263 }
 264 #endif