/*

 * Portions of this file are copyrighted by:

 * Copyright (c) 2016 VMware, Inc. All rights reserved.

 * Use is subject to license terms specified in the COPYING file

 * distributed with the Net-SNMP package.

 */

#include <net-snmp/net-snmp-config.h>

#include <net-snmp/net-snmp-features.h>

#include <net-snmp/net-snmp-includes.h>

#include <net-snmp/library/snmpCallbackDomain.h>

#include <net-snmp/agent/net-snmp-agent-includes.h>

#include "agent_global_vars.h"

#include "agentx/subagent.h"

#include "utilities/iquery.h"

netsnmp_feature_child_of(iquery_all, libnetsnmpmibs);

netsnmp_feature_child_of(iquery, iquery_all);

netsnmp_feature_child_of(iquery_community_session, iquery_all);

netsnmp_feature_child_of(iquery_pdu_session, iquery_all);

netsnmp_feature_require(query_set_default_session);

#ifndef NETSNMP_FEATURE_REMOVE_IQUERY

void

netsnmp_parse_iquerySecLevel(const char *token, char *line)

{

    int secLevel;

#ifndef NETSNMP_FEATURE_REMOVE_RUNTIME_DISABLE_VERSION

    if (netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID,

                               NETSNMP_DS_LIB_DISABLE_V3)) {

        netsnmp_config_error("SNMPv3 disabled");

    } else

#endif

    if ((secLevel = parse_secLevel_conf( token, line )) >= 0 ) {

        netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                           NETSNMP_DS_AGENT_INTERNAL_SECLEVEL, secLevel);

    } else {

  netsnmp_config_error("Unknown security level: %s", line);

    }

}

void

netsnmp_parse_iqueryVersion(const char *token, char *line)

{

#ifndef NETSNMP_DISABLE_SNMPV1

    if (!strcmp( line, "1" )

#ifndef NETSNMP_FEATURE_REMOVE_RUNTIME_DISABLE_VERSION

        && !netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID,

                                NETSNMP_DS_LIB_DISABLE_V1)

#endif

        )

        netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                           NETSNMP_DS_AGENT_INTERNAL_VERSION, SNMP_VERSION_1);

    else 

#endif

#ifndef NETSNMP_DISABLE_SNMPV2C

        if ((!strcmp( line, "2"  ) || !strcasecmp( line, "2c" ))

#ifndef NETSNMP_FEATURE_REMOVE_RUNTIME_DISABLE_VERSION

            && !netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID,

                                       NETSNMP_DS_LIB_DISABLE_V2c)

#endif

            )

        netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                           NETSNMP_DS_AGENT_INTERNAL_VERSION, SNMP_VERSION_2c);

    else 

#endif

         if (!strcmp( line, "3" )

#ifndef NETSNMP_FEATURE_REMOVE_RUNTIME_DISABLE_VERSION

             && !netsnmp_ds_get_boolean(NETSNMP_DS_LIBRARY_ID,

                                        NETSNMP_DS_LIB_DISABLE_V3)

#endif

             )

        netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                           NETSNMP_DS_AGENT_INTERNAL_VERSION, SNMP_VERSION_3);

    else {

  netsnmp_config_error("Unknown/disabled version: %s", line);

    }

}

  /*

   * Set up a default session for running internal queries.

   * This needs to be done before the config files are read,

   *  so that it is available for "monitor" directives...

   */

int

_init_default_iquery_session( int majorID, int minorID,

                              void *serverargs, void *clientarg)

{

    char *secName = netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID,

                                          NETSNMP_DS_AGENT_INTERNAL_SECNAME);

    if (secName)

        netsnmp_query_set_default_session(

             netsnmp_iquery_user_session(secName));

    return SNMPERR_SUCCESS;

}

  /*

   * ... Unfortunately, the internal engine ID is not set up

   * until later, so this default session is incomplete.

   * The resulting engineID probe runs into problems,

   * causing the very first internal query to time out.

   *   Updating the default session with the internal engineID

   * once it has been set, fixes this problem.

   */

int

_tweak_default_iquery_session( int majorID, int minorID,

                              void *serverargs, void *clientarg)

{

    u_char eID[SNMP_MAXBUF_SMALL];

    size_t elen;

    netsnmp_session *s = netsnmp_query_get_default_session_unchecked();

    if ( s && s->securityEngineIDLen == 0 ) {

        elen = snmpv3_get_engineID(eID, sizeof(eID));

        free(s->securityEngineID);

        s->securityEngineID = netsnmp_memdup(eID, elen);

        s->securityEngineIDLen = elen;

    }

    return SNMPERR_SUCCESS;

}

void init_iquery(void){

    char *type = netsnmp_ds_get_string(NETSNMP_DS_LIBRARY_ID, 

                                       NETSNMP_DS_LIB_APPTYPE);

    netsnmp_ds_register_premib(ASN_OCTET_STR, type, "agentSecName",

                               NETSNMP_DS_APPLICATION_ID,

                               NETSNMP_DS_AGENT_INTERNAL_SECNAME);

    netsnmp_ds_register_premib(ASN_OCTET_STR, type, "iquerySecName",

                               NETSNMP_DS_APPLICATION_ID,

                               NETSNMP_DS_AGENT_INTERNAL_SECNAME);

    snmpd_register_config_handler("iqueryVersion",

                                   netsnmp_parse_iqueryVersion, NULL,

                                   "1 | 2c | 3");

    snmpd_register_config_handler("iquerySecLevel",

                                   netsnmp_parse_iquerySecLevel, NULL,

                                   "noAuthNoPriv | authNoPriv | authPriv");

    /*

     * Set defaults

     */

    netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                       NETSNMP_DS_AGENT_INTERNAL_VERSION, SNMP_VERSION_3);

    netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,

                       NETSNMP_DS_AGENT_INTERNAL_SECLEVEL, SNMP_SEC_LEVEL_AUTHNOPRIV);

    snmp_register_callback(SNMP_CALLBACK_LIBRARY, 

                           SNMP_CALLBACK_POST_PREMIB_READ_CONFIG,

                           _init_default_iquery_session, NULL);

    snmp_register_callback(SNMP_CALLBACK_LIBRARY, 

                           SNMP_CALLBACK_POST_READ_CONFIG,

                           _tweak_default_iquery_session, NULL);

}

    /**************************

     *

     *  APIs to construct an "internal query" session

     *

     **************************/

#ifndef NETSNMP_FEATURE_REMOVE_IQUERY_PDU_SESSION

netsnmp_session *netsnmp_iquery_pdu_session(netsnmp_pdu* pdu) {

    if (!pdu || NETSNMP_RUNTIME_PROTOCOL_SKIP(pdu->version))

       return NULL;

    if (pdu->version == SNMP_VERSION_3)

        return netsnmp_iquery_session( pdu->securityName, 

                           pdu->version,

                           pdu->securityModel,

                           pdu->securityLevel,

                           pdu->securityEngineID,

                           pdu->securityEngineIDLen);

    else

        return netsnmp_iquery_session((char *) pdu->community, 

                           pdu->version,

                           pdu->version+1,

                           SNMP_SEC_LEVEL_NOAUTH,

                           pdu->securityEngineID,

                           pdu->securityEngineIDLen);

}

#endif /* NETSNMP_FEATURE_REMOVE_IQUERY_PDU_SESSION */

netsnmp_session *netsnmp_iquery_user_session(char* secName){

    u_char eID[SNMP_MAXBUF_SMALL];

    size_t elen = snmpv3_get_engineID(eID, sizeof(eID));

    return netsnmp_iquery_session( secName, 

                           SNMP_VERSION_3,

                           SNMP_SEC_MODEL_USM,

                           SNMP_SEC_LEVEL_AUTHNOPRIV, eID, elen);

}

#ifndef NETSNMP_FEATURE_REMOVE_IQUERY_COMMUNITY_SESSION

netsnmp_session *netsnmp_iquery_community_session( char* community, int version ) { 

    u_char eID[SNMP_MAXBUF_SMALL];

    size_t elen = snmpv3_get_engineID(eID, sizeof(eID));

    return netsnmp_iquery_session( community, version, version+1,

                           SNMP_SEC_LEVEL_NOAUTH, eID, elen);

}

#endif /* NETSNMP_FEATURE_REMOVE_IQUERY_COMMUNITY_SESSION */

netsnmp_session *netsnmp_iquery_session(char* secName,   int   version,

                                        int   secModel,  int   secLevel,

                                       u_char* engineID, size_t engIDLen) {

    /*

     * This routine creates a completely new session every time.

     * It might be worth keeping track of which 'secNames' already

     * have iquery sessions created, and re-using the appropriate one.  

     */

    netsnmp_session *ss = NULL;

    NETSNMP_RUNTIME_PROTOCOL_CHECK(version, unsupported_version);

#ifdef NETSNMP_TRANSPORT_CALLBACK_DOMAIN

    ss = netsnmp_callback_open( callback_master_num, NULL, NULL, NULL);

    if (ss) {

        ss->version       = version;

        ss->securityModel = secModel;

        ss->securityLevel = secLevel;

        ss->securityEngineID = netsnmp_memdup(engineID, engIDLen);

        ss->securityEngineIDLen = engIDLen;

        if ( version == SNMP_VERSION_3 ) {

            ss->securityNameLen = strlen(secName);

            ss->securityName = netsnmp_memdup(secName, ss->securityNameLen + 1);

        } else {

            ss->community = netsnmp_memdup(secName, strlen(secName));

            ss->community_len = strlen(secName);

        }

        ss->myvoid = (void *)netsnmp_check_outstanding_agent_requests;

        ss->flags |= SNMP_FLAGS_RESP_CALLBACK | SNMP_FLAGS_DONT_PROBE;

    }

#endif

  unsupported_version:

    return ss;

}

#else /* NETSNMP_FEATURE_REMOVE_IQUERY */

netsnmp_feature_unused(iquery);

#endif /* NETSNMP_FEATURE_REMOVE_IQUERY */