Diff: cyclone_tcp/dhcp/dhcp_common.c

Revision:

0:8918a71cdbe9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cyclone_tcp/dhcp/dhcp_common.c	Sat Feb 04 18:15:49 2017 +0000
@@ -0,0 +1,155 @@
+/**
+ * @file dhcp_common.c
+ * @brief Functions common to DHCP client, server and BOOTP relay agent
+ *
+ * @section License
+ *
+ * Copyright (C) 2010-2017 Oryx Embedded SARL. All rights reserved.
+ *
+ * This file is part of CycloneTCP Open.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * @section Description
+ *
+ * The Dynamic Host Configuration Protocol is used to provide configuration
+ * parameters to hosts. Refer to the following RFCs for complete details:
+ * - RFC 2131: Dynamic Host Configuration Protocol
+ * - RFC 2132: DHCP Options and BOOTP Vendor Extensions
+ * - RFC 4039: Rapid Commit Option for the DHCP version 4
+ *
+ * @author Oryx Embedded SARL (www.oryx-embedded.com)
+ * @version 1.7.6
+ **/
+
+//Switch to the appropriate trace level
+#define TRACE_LEVEL DHCP_TRACE_LEVEL
+
+//Dependencies
+#include "core/net.h"
+#include "dhcp/dhcp_common.h"
+#include "debug.h"
+
+//Check TCP/IP stack configuration
+#if (IPV4_SUPPORT == ENABLED)
+
+
+/**
+ * @brief Append an option to a DHCP message
+ * @param[in] message Pointer to the DHCP message
+ * @param[in] optionCode Option code
+ * @param[in] optionValue Option value
+ * @param[in] optionLength Length of the option value
+ **/
+
+void dhcpAddOption(DhcpMessage *message, uint8_t optionCode,
+   const void *optionValue, size_t optionLength)
+{
+   size_t n;
+   DhcpOption *option;
+
+   //Point to the very first option
+   n = 0;
+
+   //Parse DHCP options
+   while(1)
+   {
+      //Point to the current option
+      option = (DhcpOption *) (message->options + n);
+
+      //End option detected?
+      if(option->code == DHCP_OPT_END)
+         break;
+
+      //Jump to next the next option
+      n += sizeof(DhcpOption) + option->length;
+   }
+
+   //Sanity check
+   if(optionLength <= UINT8_MAX)
+   {
+      //Point to the buffer where the option is to be written
+      option = (DhcpOption *) (message->options + n);
+
+      //Option code
+      option->code = optionCode;
+      //Option length
+      option->length = (uint8_t) optionLength;
+      //Option value
+      memcpy(option->value, optionValue, optionLength);
+
+      //Jump to next the next option
+      n += sizeof(DhcpOption) + option->length;
+
+      //Point to the buffer where the option is to be written
+      option = (DhcpOption *) (message->options + n);
+
+      //Always terminate the options field with 255
+      option->code = DHCP_OPT_END;
+   }
+}
+
+
+/**
+ * @brief Find the specified option in a DHCP message
+ * @param[in] message Pointer to the DHCP message
+ * @param[in] length Length of the message
+ * @param[in] optionCode Code of the option to find
+ * @return If the specified option is found, a pointer to the corresponding
+ *   option is returned. Otherwise NULL pointer is returned
+ **/
+
+DhcpOption *dhcpGetOption(const DhcpMessage *message,
+   size_t length, uint8_t optionCode)
+{
+   uint_t i;
+   DhcpOption *option;
+
+   //Make sure the DHCP header is valid
+   if(length < sizeof(DhcpMessage))
+      return NULL;
+   //Get the length of the options field
+   length -= sizeof(DhcpMessage);
+
+   //Parse DHCP options
+   for(i = 0; i < length; i++)
+   {
+      //Point to the current option
+      option = (DhcpOption *) (message->options + i);
+
+      //Pad option detected?
+      if(option->code == DHCP_OPT_PAD)
+         continue;
+      //End option detected?
+      if(option->code == DHCP_OPT_END)
+         break;
+      //Check option length
+      if((i + 1) >= length || (i + 1 + option->length) >= length)
+         break;
+
+      //Current option code matches the specified one?
+      if(option->code == optionCode)
+         return option;
+
+      //Jump to the next option
+      i += option->length + 1;
+   }
+
+   //Specified option code not found
+   return NULL;
+}
+
+#endif
+