Diff: cyclone_tcp/snmp/snmp_agent_dispatch.c

Revision:

0:8918a71cdbe9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cyclone_tcp/snmp/snmp_agent_dispatch.c	Sat Feb 04 18:15:49 2017 +0000
@@ -0,0 +1,394 @@
+/**
+ * @file snmp_agent_dispatch.c
+ * @brief SNMP message dispatching
+ *
+ * @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.
+ *
+ * @author Oryx Embedded SARL (www.oryx-embedded.com)
+ * @version 1.7.6
+ **/
+
+//Switch to the appropriate trace level
+#define TRACE_LEVEL SNMP_TRACE_LEVEL
+
+//Dependencies
+#include "core/net.h"
+#include "snmp/snmp_agent.h"
+#include "snmp/snmp_agent_dispatch.h"
+#include "snmp/snmp_agent_pdu.h"
+#include "snmp/snmp_agent_misc.h"
+#include "mibs/mib2_module.h"
+#include "crypto.h"
+#include "asn1.h"
+#include "oid.h"
+#include "debug.h"
+
+//Check TCP/IP stack configuration
+#if (SNMP_AGENT_SUPPORT == ENABLED)
+
+
+/**
+ * @brief Process incoming SNMP message
+ * @param[in] context Pointer to the SNMP agent context
+ * @return Error code
+ **/
+
+error_t snmpProcessMessage(SnmpAgentContext *context)
+{
+   error_t error;
+
+   //Total number of messages delivered to the SNMP entity from the
+   //transport service
+   MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpInPkts, 1);
+
+   //Refresh SNMP engine time
+   snmpRefreshEngineTime(context);
+
+   //Message parsing initialization
+   snmpInitMessage(&context->request);
+
+   //Parse SNMP message header
+   error = snmpParseMessageHeader(&context->request);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //The SNMP agent verifies the version number. If there is a mismatch,
+   //it discards the datagram and performs no further actions
+   if(context->request.version < context->settings.versionMin ||
+      context->request.version > context->settings.versionMax)
+   {
+      //Debug message
+      TRACE_WARNING("  Invalid SNMP version!\r\n");
+      //Discard incoming SNMP message
+      return ERROR_INVALID_VERSION;
+   }
+
+#if (SNMP_V1_SUPPORT == ENABLED)
+   //SNMPv1 version?
+   if(context->request.version == SNMP_VERSION_1)
+   {
+      //Process incoming SNMPv1 message
+      error = snmpv1ProcessMessage(context);
+   }
+   else
+#endif
+#if (SNMP_V2C_SUPPORT == ENABLED)
+   //SNMPv2c version?
+   if(context->request.version == SNMP_VERSION_2C)
+   {
+      //Process incoming SNMPv2c message
+      error = snmpv2cProcessMessage(context);
+   }
+   else
+#endif
+#if (SNMP_V3_SUPPORT == ENABLED)
+   //SNMPv3 version?
+   if(context->request.version == SNMP_VERSION_3)
+   {
+      //Process incoming SNMPv3 message
+      error = snmpv3ProcessMessage(context);
+   }
+   else
+#endif
+   //Invalid SNMP version?
+   {
+      //Debug message
+      TRACE_WARNING("  Invalid SNMP version!\r\n");
+
+      //Total number of SNMP messages which were delivered to the SNMP
+      //protocol entity and were for an unsupported SNMP version
+      MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpInBadVersions, 1);
+
+      //Discard incoming SNMP message
+      error = ERROR_INVALID_VERSION;
+   }
+
+   //Check status code
+   if(error == NO_ERROR)
+   {
+      //Total number of messages which were passed from the SNMP protocol
+      //entity to the transport service
+      MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpOutPkts, 1);
+   }
+   else if(error == ERROR_INVALID_TAG)
+   {
+      //Total number of ASN.1 or BER errors encountered by the SNMP protocol
+      //entity when decoding received SNMP messages
+      MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpInASNParseErrs, 1);
+   }
+
+   //Return status code
+   return error;
+}
+
+
+/**
+ * @brief Process incoming SNMPv1 message
+ * @param[in] context Pointer to the SNMP agent context
+ * @return Error code
+ **/
+
+error_t snmpv1ProcessMessage(SnmpAgentContext *context)
+{
+   error_t error;
+
+#if (SNMP_V1_SUPPORT == ENABLED)
+   //Parse community name
+   error = snmpParseCommunity(&context->request);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Information about the community name is extracted from the local
+   //configuration datastore
+   context->user = snmpFindUser(context, context->request.community,
+      context->request.communityLen);
+
+   //Invalid community name?
+   if(context->user == NULL)
+   {
+      //Debug message
+      TRACE_WARNING("  Invalid community name!\r\n");
+
+      //Total number of SNMP messages delivered to the SNMP protocol entity
+      //which used a SNMP community name not known to said entity
+      MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpInBadCommunityNames, 1);
+
+      //Report an error
+      return ERROR_UNKNOWN_USER_NAME;
+   }
+
+   //Process PDU
+   error = snmpProcessPdu(context);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Format SNMP message header
+   error = snmpWriteMessageHeader(&context->response);
+#else
+   //Report an error
+   error = ERROR_INVALID_VERSION;
+#endif
+
+   //Return status code
+   return error;
+}
+
+
+/**
+ * @brief Process incoming SNMPv2c message
+ * @param[in] context Pointer to the SNMP agent context
+ * @return Error code
+ **/
+
+error_t snmpv2cProcessMessage(SnmpAgentContext *context)
+{
+   error_t error;
+
+#if (SNMP_V2C_SUPPORT == ENABLED)
+   //Parse community name
+   error = snmpParseCommunity(&context->request);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Information about the community name is extracted from the local
+   //configuration datastore
+   context->user = snmpFindUser(context, context->request.community,
+      context->request.communityLen);
+
+   //Invalid community name?
+   if(context->user == NULL)
+   {
+      //Debug message
+      TRACE_WARNING("  Invalid community name!\r\n");
+
+      //Total number of SNMP messages delivered to the SNMP protocol entity
+      //which used a SNMP community name not known to said entity
+      MIB2_INC_COUNTER32(mib2Base.snmpGroup.snmpInBadCommunityNames, 1);
+
+      //Report an error
+      return ERROR_UNKNOWN_USER_NAME;
+   }
+
+   //Process PDU
+   error = snmpProcessPdu(context);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Format SNMP message header
+   error = snmpWriteMessageHeader(&context->response);
+#else
+   //Report an error
+   error = ERROR_INVALID_VERSION;
+#endif
+
+   //Return status code
+   return error;
+}
+
+
+/**
+ * @brief Process incoming SNMPv3 message
+ * @param[in] context Pointer to the SNMP agent context
+ * @return Error code
+ **/
+
+error_t snmpv3ProcessMessage(SnmpAgentContext *context)
+{
+   error_t error;
+
+#if (SNMP_V3_SUPPORT == ENABLED)
+   //Parse msgGlobalData field
+   error = snmpParseGlobalData(&context->request);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Parse msgSecurityParameters field
+   error = snmpParseSecurityParameters(&context->request);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Start of exception handling block
+   do
+   {
+      //Information about the value of the msgUserName field is extracted
+      //from the local configuration datastore
+      context->user = snmpFindUser(context, context->request.msgUserName,
+         context->request.msgUserNameLen);
+
+      //Check security parameters
+      error = snmpCheckSecurityParameters(context->user, &context->request,
+         context->contextEngine, context->contextEngineLen);
+      //Invalid security parameters?
+      if(error)
+         break;
+
+      //Check whether the authFlag is set
+      if(context->request.msgFlags & SNMP_MSG_FLAG_AUTH)
+      {
+         //Authenticate incoming SNMP message
+         error = snmpAuthIncomingMessage(context->user, &context->request);
+         //Data authentication failed?
+         if(error)
+            break;
+
+         //Replay protection
+         error = snmpCheckEngineTime(context, &context->request);
+         //Message outside of the time window?
+         if(error)
+            break;
+      }
+
+      //Check whether the privFlag is set
+      if(context->request.msgFlags & SNMP_MSG_FLAG_PRIV)
+      {
+         //Decrypt data
+         error = snmpDecryptData(context->user, &context->request);
+         //Data decryption failed?
+         if(error)
+            break;
+      }
+
+      //End of exception handling block
+   } while(0);
+
+   //Check error indication
+   if(error == ERROR_UNSUPPORTED_SECURITY_LEVEL ||
+      error == ERROR_NOT_IN_TIME_WINDOW ||
+      error == ERROR_UNKNOWN_USER_NAME ||
+      error == ERROR_UNKNOWN_ENGINE_ID ||
+      error == ERROR_AUTHENTICATION_FAILED ||
+      error == ERROR_DECRYPTION_FAILED)
+   {
+      //Report the error indication to the remote SNMP engine using a Report-PDU
+      error = snmpFormatReportPdu(context, error);
+      //Any error to report?
+      if(error)
+         return error;
+   }
+   else if(error == NO_ERROR)
+   {
+      //Parse scopedPDU
+      error = snmpParseScopedPdu(&context->request);
+      //Any error to report?
+      if(error)
+         return error;
+
+      //Process PDU
+      error = snmpProcessPdu(context);
+      //Any error to report?
+      if(error)
+         return error;
+   }
+   else
+   {
+      //Stop processing
+      return error;
+   }
+
+   //Format scopedPDU
+   error = snmpWriteScopedPdu(&context->response);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Check whether the privFlag is set
+   if(context->response.msgFlags & SNMP_MSG_FLAG_PRIV)
+   {
+      //Encrypt data
+      error = snmpEncryptData(context->user, &context->response, &context->salt);
+      //Any error to report?
+      if(error)
+         return error;
+   }
+
+   //Format SNMP message header
+   error = snmpWriteMessageHeader(&context->response);
+   //Any error to report?
+   if(error)
+      return error;
+
+   //Check whether the authFlag is set
+   if(context->response.msgFlags & SNMP_MSG_FLAG_AUTH)
+   {
+      //Authenticate outgoing SNMP message
+      error = snmpAuthOutgoingMessage(context->user, &context->response);
+      //Any error to report?
+      if(error)
+         return error;
+   }
+#else
+   //Report an error
+   error = ERROR_INVALID_VERSION;
+#endif
+
+   //Return status code
+   return error;
+}
+
+#endif
+