/*

 *  AgentX master agent

 */

/* Portions of this file are subject to the following copyright(s).  See

 * the Net-SNMP's COPYING file for more details and other copyrights

 * that may apply:

 */

/*

 * Portions of this file are copyrighted by:

 * Copyright © 2003 Sun Microsystems, 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>

#ifdef HAVE_IO_H

#include <io.h>

#endif

#include <stdio.h>

#include <sys/types.h>

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#else

#include <strings.h>

#endif

#ifdef HAVE_NETINET_IN_H

#include <netinet/in.h>

#endif

#ifdef HAVE_SYS_SOCKET_H

#include <sys/socket.h>

#endif

#include <errno.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_SYS_STAT_H

#include <sys/stat.h>

#endif

#define SNMP_NEED_REQUEST_LIST

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

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

#include "snmpd.h"

#include "agentx/protocol.h"

#include "agentx/master_admin.h"

netsnmp_feature_require(handler_mark_requests_as_delegated);

netsnmp_feature_require(unix_socket_paths);

netsnmp_feature_require(free_agent_snmp_session_by_session);

void

real_init_master(void)

{

    netsnmp_session sess, *session = NULL;

    char *agentx_sockets;

    char *cp1;

    if (netsnmp_ds_get_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_ROLE) != MASTER_AGENT)

        return;

    if (netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID,

                              NETSNMP_DS_AGENT_X_SOCKET)) {

       agentx_sockets = strdup(netsnmp_ds_get_string(NETSNMP_DS_APPLICATION_ID,

                                                     NETSNMP_DS_AGENT_X_SOCKET));

#ifdef NETSNMP_AGENTX_DOM_SOCK_ONLY

       if (agentx_sockets[0] != '/') {

           /* unix:/path */

           if (agentx_sockets[5] != '/') {

               snmp_log(LOG_ERR,

                    "Error: %s transport is not supported, disabling agentx/master.\n", agentx_sockets);

               SNMP_FREE(agentx_sockets);

               return;

           }

       }

#endif

    } else {

        agentx_sockets = strdup("");

    }

    DEBUGMSGTL(("agentx/master", "initializing...\n"));

    snmp_sess_init(&sess);

    sess.version = AGENTX_VERSION_1;

    sess.flags |= SNMP_FLAGS_STREAM_SOCKET;

    sess.timeout = netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

                                      NETSNMP_DS_AGENT_AGENTX_TIMEOUT);

    sess.retries = netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

                                      NETSNMP_DS_AGENT_AGENTX_RETRIES);

#ifdef NETSNMP_TRANSPORT_UNIX_DOMAIN

    {

  int agentx_dir_perm =

      netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

             NETSNMP_DS_AGENT_X_DIR_PERM);

  if (agentx_dir_perm == 0)

      agentx_dir_perm = NETSNMP_AGENT_DIRECTORY_MODE;

  netsnmp_unix_create_path_with_mode(agentx_dir_perm);

    }

#endif

    cp1 = agentx_sockets;

    while (cp1) {

        netsnmp_transport *t;

        /*

         *  If the AgentX socket string contains multiple descriptors,

         *  then pick this apart and handle them one by one.

         *

         */

        sess.peername = cp1;

        cp1 = strchr(sess.peername, ',');

        if (cp1 != NULL) {

            *cp1++ = '\0';

  }

        /*

         *  Let 'snmp_open' interpret the descriptor.

         */

        sess.local_port = AGENTX_PORT;      /* Indicate server & set default port */

        sess.callback = handle_master_agentx_packet;

        errno = 0;

        t = netsnmp_transport_open_server("agentx", sess.peername);

        if (t == NULL) {

            /*

             * diagnose snmp_open errors with the input netsnmp_session

             * pointer.

             */

            char buf[1024];

            if (!netsnmp_ds_get_boolean(NETSNMP_DS_APPLICATION_ID,

                                        NETSNMP_DS_AGENT_NO_ROOT_ACCESS)) {

                snprintf(buf, sizeof(buf),

                         "Error: Couldn't open a master agentx socket to "

                         "listen on (%s)", sess.peername);

                snmp_sess_perror(buf, &sess);

                exit(1);

            } else {

                snprintf(buf, sizeof(buf),

                         "Warning: Couldn't open a master agentx socket to "

                         "listen on (%s)", sess.peername);

                netsnmp_sess_log_error(LOG_WARNING, buf, &sess);

            }

        } else {

#ifdef NETSNMP_TRANSPORT_UNIX_DOMAIN

            if (t->domain == netsnmp_UnixDomain && t->local != NULL) {

                /*

                 * Apply any settings to the ownership/permissions of the

                 * AgentX socket

                 */

                int agentx_sock_perm =

                    netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

                                       NETSNMP_DS_AGENT_X_SOCK_PERM);

                int agentx_sock_user =

                    netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

                                       NETSNMP_DS_AGENT_X_SOCK_USER);

                int agentx_sock_group =

                    netsnmp_ds_get_int(NETSNMP_DS_APPLICATION_ID,

                                       NETSNMP_DS_AGENT_X_SOCK_GROUP);

                char name[sizeof(struct sockaddr_un) + 1];

                memcpy(name, t->local, t->local_length);

                name[t->local_length] = '\0';

                if (agentx_sock_perm != 0)

                    chmod(name, agentx_sock_perm);

                if (agentx_sock_user || agentx_sock_group) {

                    /*

                     * If either of user or group haven't been set,

                     *  then leave them unchanged.

                     */

                    if (agentx_sock_user == 0 )

                        agentx_sock_user = -1;

                    if (agentx_sock_group == 0 )

                        agentx_sock_group = -1;

                    NETSNMP_IGNORE_RESULT(chown(name, agentx_sock_user,

                                                agentx_sock_group));

                }

            }

#endif

            session =

                snmp_add_full(&sess, t, NULL, agentx_parse, NULL, NULL,

                              agentx_realloc_build, agentx_check_packet, NULL);

            /* snmp_add_full() frees 't' upon failure. */

            if (!session)

                t = NULL;

        }

        if (session == NULL) {

            netsnmp_transport_free(t);

        }

    }

#ifdef NETSNMP_TRANSPORT_UNIX_DOMAIN

    netsnmp_unix_dont_create_path();

#endif

    SNMP_FREE(agentx_sockets);

    DEBUGMSGTL(("agentx/master", "initializing...   DONE\n"));

}

        /*

         * Handle the response from an AgentX subagent,

         *   merging the answers back into the original query

         */

int

agentx_got_response(int operation,

                    netsnmp_session * session,

                    int reqid, netsnmp_pdu *pdu, void *magic)

{

    netsnmp_delegated_cache *cache = (netsnmp_delegated_cache *) magic;

    int             i, ret;

    netsnmp_request_info *requests, *request;

    netsnmp_variable_list *var;

    cache = netsnmp_handler_check_cache(cache);

    if (!cache) {

        DEBUGMSGTL(("agentx/master", "response too late on session %8p\n",

                    session));

        /* response is too late, free the cache */

        if (magic)

            netsnmp_free_delegated_cache((netsnmp_delegated_cache*) magic);

        return 1;

    }

    requests = cache->requests;

    switch (operation) {

    case NETSNMP_CALLBACK_OP_TIMED_OUT:{

            struct session_list *s = snmp_sess_pointer(session);

            DEBUGMSGTL(("agentx/master", "timeout on session %8p req=0x%x\n",

                        session, (unsigned)reqid));

            netsnmp_handler_mark_requests_as_delegated(requests,

                                       REQUEST_IS_NOT_DELEGATED);

            netsnmp_set_request_error(cache->reqinfo, requests,

                                      /* XXXWWW: should be index=0 */

                                      SNMP_ERR_GENERR);

            /*

             * This is a bit sledgehammer because the other sessions on this

             * transport may be okay (e.g. some thread in the subagent has

             * wedged, but the others are alright).  OTOH the overwhelming

             * probability is that the whole agent has died somehow.  

             */

            if (s != NULL) {

                netsnmp_transport *t = snmp_sess_transport(s);

                close_agentx_session(session, -1);

                if (t != NULL) {

                    DEBUGMSGTL(("agentx/master", "close transport\n"));

                    t->f_close(t);

                } else {

                    DEBUGMSGTL(("agentx/master", "NULL transport??\n"));

                }

            } else {

                DEBUGMSGTL(("agentx/master", "NULL sess_pointer??\n"));

            }

            netsnmp_free_delegated_cache(cache);

            return 0;

        }

    case NETSNMP_CALLBACK_OP_DISCONNECT:

    case NETSNMP_CALLBACK_OP_SEND_FAILED:

        if (operation == NETSNMP_CALLBACK_OP_DISCONNECT) {

            DEBUGMSGTL(("agentx/master", "disconnect on session %8p\n",

                        session));

        } else {

            DEBUGMSGTL(("agentx/master", "send failed on session %8p\n",

                        session));

        }

        close_agentx_session(session, -1);

        netsnmp_handler_mark_requests_as_delegated(requests,

                                                   REQUEST_IS_NOT_DELEGATED);

        netsnmp_set_request_error(cache->reqinfo, requests,     /* XXXWWW: should be index=0 */

                                  SNMP_ERR_GENERR);

        netsnmp_free_delegated_cache(cache);

        return 0;

    case NETSNMP_CALLBACK_OP_RESEND:

        DEBUGMSGTL(("agentx/master", "resend on session %8p req=0x%x\n",

                    session, (unsigned)reqid));

        return 0;

    case NETSNMP_CALLBACK_OP_RECEIVED_MESSAGE:

        /*

         * This session is alive 

         */

        CLEAR_SNMP_STRIKE_FLAGS(session->flags);

        break;

    default:

        snmp_log(LOG_ERR, "Unknown operation %d in agentx_got_response\n",

                 operation);

        netsnmp_free_delegated_cache(cache);

        return 0;

    }

    DEBUGMSGTL(("agentx/master", "got response errstat=%ld, (req=0x%x,trans="

                "0x%x,sess=0x%x)\n",

                pdu->errstat, (unsigned)pdu->reqid, (unsigned)pdu->transid,

    (unsigned)pdu->sessid));

    if (pdu->errstat != AGENTX_ERR_NOERROR) {

        /* [RFC 2471 - 7.2.5.2.]

         *

         *   1) For any received AgentX response PDU, if res.error is

         *      not `noError', the SNMP response PDU's error code is

         *      set to this value.  If res.error contains an AgentX

         *      specific value (e.g.  `parseError'), the SNMP response

         *      PDU's error code is set to a value of genErr instead.

         *      Also, the SNMP response PDU's error index is set to

         *      the index of the variable binding corresponding to the

         *      failed VarBind in the subagent's AgentX response PDU.

         *

         *      All other AgentX response PDUs received due to

         *      processing this SNMP request are ignored.  Processing

         *      is complete; the SNMP Response PDU is ready to be sent

         *      (see section 7.2.6, "Sending the SNMP Response-PDU").

         */

        int err;

        DEBUGMSGTL(("agentx/master",

                    "agentx_got_response() error branch\n"));

        switch (pdu->errstat) {

        case AGENTX_ERR_PARSE_FAILED:

        case AGENTX_ERR_REQUEST_DENIED:

        case AGENTX_ERR_PROCESSING_ERROR:

            err = SNMP_ERR_GENERR;

            break;

        default:

            err = pdu->errstat;

        }

        ret = 0;

        for (request = requests, i = 1; request;

             request = request->next, i++) {

            if (i == pdu->errindex) {

                /*

                 * Mark this varbind as the one generating the error.

                 * Note that the AgentX errindex may not match the

                 * position in the original SNMP PDU (request->index)

                 */

                netsnmp_set_request_error(cache->reqinfo, request,

                                          err);

                ret = 1;

            }

            request->delegated = REQUEST_IS_NOT_DELEGATED;

        }

        if (!ret) {

            /*

             * ack, unknown, mark the first one

             */

            netsnmp_set_request_error(cache->reqinfo, requests,

                                      SNMP_ERR_GENERR);

        }

        netsnmp_free_delegated_cache(cache);

        DEBUGMSGTL(("agentx/master", "end error branch\n"));

        return 1;

    } else if (cache->reqinfo->mode == MODE_GET ||

               cache->reqinfo->mode == MODE_GETNEXT ||

               cache->reqinfo->mode == MODE_GETBULK) {

        /*

         * Replace varbinds for data request types, but not SETs.  

         */

        DEBUGMSGTL(("agentx/master",

                    "agentx_got_response() beginning...\n"));

        for (var = pdu->variables, request = requests; request && var;

             request = request->next, var = var->next_variable) {

            /*

             * Otherwise, process successful requests

             */

            DEBUGMSGTL(("agentx/master",

                        "  handle_agentx_response: processing: "));

            DEBUGMSGOID(("agentx/master", var->name, var->name_length));

            DEBUGMSG(("agentx/master", "\n"));

            if (netsnmp_ds_get_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_VERBOSE)) {

                DEBUGMSGTL(("agentx/master", "    >> "));

                DEBUGMSGVAR(("agentx/master", var));

                DEBUGMSG(("agentx/master", "\n"));

            }

            /*

             * update the oid in the original request 

             */

            if (var->type != SNMP_ENDOFMIBVIEW) {

                snmp_set_var_typed_value(request->requestvb, var->type,

                                         var->val.string, var->val_len);

                snmp_set_var_objid(request->requestvb, var->name,

                                   var->name_length);

            }

            request->delegated = REQUEST_IS_NOT_DELEGATED;

        }

        if (request || var) {

            /*

             * ack, this is bad.  The # of varbinds don't match and

             * there is no way to fix the problem 

             */

            snmp_log(LOG_ERR,

                     "response to agentx request illegal.  bailing out.\n");

            netsnmp_set_request_error(cache->reqinfo, requests,

                                      SNMP_ERR_GENERR);

        }

        if (cache->reqinfo->mode == MODE_GETBULK)

            netsnmp_bulk_to_next_fix_requests(requests);

    } else {

        /*

         * mark set requests as handled 

         */

        for (request = requests; request; request = request->next) {

            request->delegated = REQUEST_IS_NOT_DELEGATED;

        }

    }

    DEBUGMSGTL(("agentx/master",

                "handle_agentx_response() finishing...\n"));

    netsnmp_free_delegated_cache(cache);

    return 1;

}

/*

 *

 * AgentX State diagram.  [mode] = internal mode it's mapped from:

 *

 * TESTSET -success-> COMMIT -success-> CLEANUP

 * [RESERVE1]         [ACTION]          [COMMIT]

 *    |                 |

 *    |                 \--failure-> UNDO

 *    |                              [UNDO]

 *    |

 *     --failure-> CLEANUP

 *                 [FREE]

 */

int

agentx_master_handler(netsnmp_mib_handler *handler,

                      netsnmp_handler_registration *reginfo,

                      netsnmp_agent_request_info *reqinfo,

                      netsnmp_request_info *requests)

{

    netsnmp_session *ax_session = (netsnmp_session *) handler->myvoid;

    netsnmp_request_info *request = requests;

    netsnmp_pdu    *pdu;

    void           *cb_data;

    int             result;

    DEBUGMSGTL(("agentx/master",

                "agentx master handler starting, mode = 0x%02x\n",

                reqinfo->mode));

    if (!ax_session) {

        netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_GENERR);

        return SNMP_ERR_NOERROR;

    }        

    /*

     * build a new pdu based on the pdu type coming in 

     */

    switch (reqinfo->mode) {

    case MODE_GET:

        pdu = snmp_pdu_create(AGENTX_MSG_GET);

        break;

    case MODE_GETNEXT:

        pdu = snmp_pdu_create(AGENTX_MSG_GETNEXT);

        break;

    case MODE_GETBULK:         /* WWWXXX */

        pdu = snmp_pdu_create(AGENTX_MSG_GETNEXT);

        break;

#ifndef NETSNMP_NO_WRITE_SUPPORT

    case MODE_SET_RESERVE1:

        pdu = snmp_pdu_create(AGENTX_MSG_TESTSET);

        break;

    case MODE_SET_RESERVE2:

        /*

         * don't do anything here for AgentX.  Assume all is fine

         * and go on since AgentX only has one test phase. 

         */

        return SNMP_ERR_NOERROR;

    case MODE_SET_ACTION:

        pdu = snmp_pdu_create(AGENTX_MSG_COMMITSET);

        break;

    case MODE_SET_UNDO:

        pdu = snmp_pdu_create(AGENTX_MSG_UNDOSET);

        break;

    case MODE_SET_COMMIT:

    case MODE_SET_FREE:

        pdu = snmp_pdu_create(AGENTX_MSG_CLEANUPSET);

        break;

#endif /* !NETSNMP_NO_WRITE_SUPPORT */

    default:

        snmp_log(LOG_WARNING,

                 "unsupported mode for agentx/master called\n");

        return SNMP_ERR_NOERROR;

    }

    if (!pdu) {

        netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_GENERR);

        return SNMP_ERR_NOERROR;

    }

    pdu->version = AGENTX_VERSION_1;

    pdu->reqid = snmp_get_next_transid();

    pdu->transid = reqinfo->asp->pdu->transid;

    pdu->sessid = ax_session->subsession->sessid;

    if (reginfo->contextName) {

        pdu->community = (u_char *) strdup(reginfo->contextName);

        pdu->community_len = strlen(reginfo->contextName);

        pdu->flags |= AGENTX_MSG_FLAG_NON_DEFAULT_CONTEXT;

    }

    if (ax_session->subsession->flags & AGENTX_MSG_FLAG_NETWORK_BYTE_ORDER)

        pdu->flags |= AGENTX_MSG_FLAG_NETWORK_BYTE_ORDER;

    while (request) {

        size_t nlen = request->requestvb->name_length;

        oid   *nptr = request->requestvb->name;

        DEBUGMSGTL(("agentx/master","request for variable ("));

        DEBUGMSGOID(("agentx/master", nptr, nlen));

        DEBUGMSG(("agentx/master", ")\n"));

        /*

         * loop through all the requests and create agentx ones out of them 

         */

        if (reqinfo->mode == MODE_GETNEXT || reqinfo->mode == MODE_GETBULK) {

            if (snmp_oid_compare(nptr, nlen, request->subtree->start_a,

                                 request->subtree->start_len) < 0) {

                DEBUGMSGTL(("agentx/master","inexact request preceding region ("));

                DEBUGMSGOID(("agentx/master", request->subtree->start_a,

                             request->subtree->start_len));

                DEBUGMSG(("agentx/master", ")\n"));

                nptr = request->subtree->start_a;

                nlen = request->subtree->start_len;

                request->inclusive = 1;

            }

            if (request->inclusive) {

                DEBUGMSGTL(("agentx/master", "INCLUSIVE varbind "));

                DEBUGMSGOID(("agentx/master", nptr, nlen));

                DEBUGMSG(("agentx/master", " scoped to "));

                DEBUGMSGOID(("agentx/master", request->range_end,

                             request->range_end_len));

                DEBUGMSG(("agentx/master", "\n"));

                snmp_pdu_add_variable(pdu, nptr, nlen, ASN_PRIV_INCL_RANGE,

                                      (u_char *) request->range_end,

                                      request->range_end_len *

                                      sizeof(oid));

                request->inclusive = 0;

            } else {

                DEBUGMSGTL(("agentx/master", "EXCLUSIVE varbind "));

                DEBUGMSGOID(("agentx/master", nptr, nlen));

                DEBUGMSG(("agentx/master", " scoped to "));

                DEBUGMSGOID(("agentx/master", request->range_end,

                             request->range_end_len));

                DEBUGMSG(("agentx/master", "\n"));

                snmp_pdu_add_variable(pdu, nptr, nlen, ASN_PRIV_EXCL_RANGE,

                                      (u_char *) request->range_end,

                                      request->range_end_len *

                                      sizeof(oid));

            }

        } else {

            snmp_pdu_add_variable(pdu, request->requestvb->name,

                                  request->requestvb->name_length,

                                  request->requestvb->type,

                                  request->requestvb->val.string,

                                  request->requestvb->val_len);

        }

        /*

         * mark the request as delayed 

         */

        if (pdu->command != AGENTX_MSG_CLEANUPSET)

            request->delegated = REQUEST_IS_DELEGATED;

        else

            request->delegated = REQUEST_IS_NOT_DELEGATED;

        /*

         * next... 

         */

        request = request->next;

    }

    /*

     * When the master sends a CleanupSet PDU, it will never get a response

     * back from the subagent. So we shouldn't allocate the

     * netsnmp_delegated_cache structure in this case.

     */

    if (pdu->command != AGENTX_MSG_CLEANUPSET)

        cb_data = netsnmp_create_delegated_cache(handler, reginfo,

                                                 reqinfo, requests,

                                                 (void *) ax_session);

    else

        cb_data = NULL;

    /*

     * send the requests out.

     */

    DEBUGMSGTL(("agentx/master", "sending pdu (req=0x%x,trans=0x%x,sess=0x%x)\n",

                (unsigned)pdu->reqid, (unsigned)pdu->transid, (unsigned)pdu->sessid));

    result = snmp_async_send(ax_session, pdu, agentx_got_response, cb_data);

    if (result == 0) {

        snmp_free_pdu(pdu);

    }

    return SNMP_ERR_NOERROR;

}