proxy.c

snmp的源代码,已经在我的ubuntu下编译通过

    *configured = NULL;
}

void
init_proxy(void)
{
    snmpd_register_config_handler("proxy", proxy_parse_config,
                                  proxy_free_config,
                                  "[snmpcmd args] host oid [remoteoid]");
}

void
shutdown_proxy(void)
{
    proxy_free_config();
}

int
proxy_handler(netsnmp_mib_handler *handler,
              netsnmp_handler_registration *reginfo,
              netsnmp_agent_request_info *reqinfo,
              netsnmp_request_info *requests)
{

    netsnmp_pdu    *pdu;
    struct simple_proxy *sp;
    oid            *ourname;
    size_t          ourlength;
    netsnmp_request_info *request = requests;
    u_char         *configured = NULL;

    DEBUGMSGTL(("proxy", "proxy handler starting, mode = %d\n",
                reqinfo->mode));

    switch (reqinfo->mode) {
    case MODE_GET:
    case MODE_GETNEXT:
    case MODE_GETBULK:         /* WWWXXX */
        pdu = snmp_pdu_create(reqinfo->mode);
        break;

    case MODE_SET_ACTION:
        pdu = snmp_pdu_create(SNMP_MSG_SET);
        break;

    case MODE_SET_UNDO:
        /*
         *  If we set successfully (status == NOERROR),
         *     we can't back out again, so need to report the fact.
         *  If we failed to set successfully, then we're fine.
         */
        for (request = requests; request; request=request->next) {
            if (request->status == SNMP_ERR_NOERROR) {
                netsnmp_set_request_error(reqinfo, requests,
                                          SNMP_ERR_UNDOFAILED);
                return SNMP_ERR_UNDOFAILED;
	    }
	}
        return SNMP_ERR_NOERROR;

    case MODE_SET_RESERVE1:
    case MODE_SET_RESERVE2:
    case MODE_SET_FREE:
    case MODE_SET_COMMIT:
        /*
         *  Nothing to do in this pass
         */
        return SNMP_ERR_NOERROR;

    default:
        snmp_log(LOG_WARNING, "unsupported mode for proxy called (%d)\n",
                               reqinfo->mode);
        return SNMP_ERR_NOERROR;
    }

    sp = (struct simple_proxy *) handler->myvoid;

    if (!pdu || !sp) {
        netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_GENERR);
        return SNMP_ERR_NOERROR;
    }

    while (request) {
        ourname = request->requestvb->name;
        ourlength = request->requestvb->name_length;

        if (sp->base_len > 0) {
            if ((ourlength - sp->name_len + sp->base_len) > MAX_OID_LEN) {
                /*
                 * too large 
                 */
                snmp_log(LOG_ERR,
                         "proxy oid request length is too long\n");
                return SNMP_ERR_NOERROR;
            }
            /*
             * suffix appended? 
             */
            DEBUGMSGTL(("proxy", "length=%d, base_len=%d, name_len=%d\n",
                        ourlength, sp->base_len, sp->name_len));
            if (ourlength > (int) sp->name_len)
                memcpy(&(sp->base[sp->base_len]), &(ourname[sp->name_len]),
                       sizeof(oid) * (ourlength - sp->name_len));
            ourlength = ourlength - sp->name_len + sp->base_len;
            ourname = sp->base;
        }

        snmp_pdu_add_variable(pdu, ourname, ourlength,
                              request->requestvb->type,
                              request->requestvb->val.string,
                              request->requestvb->val_len);
        request->delegated = 1;
        request = request->next;
    }

    /*
     * Customize session parameters based on request information
     */
    if (!proxy_fill_in_session(handler, reqinfo, (void **)&configured)) {
        netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_GENERR);
        return SNMP_ERR_NOERROR;
    }

    /*
     * send the request out 
     */
    DEBUGMSGTL(("proxy", "sending pdu\n"));
    snmp_async_send(sp->sess, pdu, proxy_got_response,
                    netsnmp_create_delegated_cache(handler, reginfo,
                                                   reqinfo, requests,
                                                   (void *) sp));

    /* Free any special parameters generated on the session */
    proxy_free_filled_in_session_args(sp->sess, (void **)&configured);

    return SNMP_ERR_NOERROR;
}

int
proxy_got_response(int operation, netsnmp_session * sess, int reqid,
                   netsnmp_pdu *pdu, void *cb_data)
{
    netsnmp_delegated_cache *cache = (netsnmp_delegated_cache *) cb_data;
    netsnmp_request_info  *requests, *request = NULL;
    netsnmp_variable_list *vars,     *var     = NULL;

    struct simple_proxy *sp;
    oid             myname[MAX_OID_LEN];
    size_t          myname_len = MAX_OID_LEN;

    cache = netsnmp_handler_check_cache(cache);

    if (!cache) {
        DEBUGMSGTL(("proxy", "a proxy request was no longer valid.\n"));
        return SNMP_ERR_NOERROR;
    }

    requests = cache->requests;


    sp = (struct simple_proxy *) cache->localinfo;

    if (!sp) {
        DEBUGMSGTL(("proxy", "a proxy request was no longer valid.\n"));
        return SNMP_ERR_NOERROR;
    }

    switch (operation) {
    case NETSNMP_CALLBACK_OP_TIMED_OUT:
        /*
         * WWWXXX: don't leave requests delayed if operation is
         * something like TIMEOUT 
         */
        DEBUGMSGTL(("proxy", "got timed out... requests = %08p\n", requests));

        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_RECEIVED_MESSAGE:
        vars = pdu->variables;

        if (pdu->errstat != SNMP_ERR_NOERROR) {
            /*
             *  If we receive an error from the proxy agent, pass it on up.
             *  The higher-level processing seems to Do The Right Thing.
             */
            DEBUGMSGTL(("proxy", "got error response (%d)\n", pdu->errstat));
            netsnmp_set_request_error(cache->reqinfo, requests, pdu->errstat);

        /*
         * update the original request varbinds with the results 
         */
	} else for (var = vars, request = requests;
             request && var;
             request = request->next, var = var->next_variable) {
            /*
             * XXX - should this be done here?
             *       Or wait until we know it's OK?
             */
            snmp_set_var_typed_value(request->requestvb, var->type,
                                     var->val.string, var->val_len);

            DEBUGMSGTL(("proxy", "got response... "));
            DEBUGMSGOID(("proxy", var->name, var->name_length));
            DEBUGMSG(("proxy", "\n"));
            request->delegated = 0;

            /*
             * Check the response oid is legitimate,
             *   and discard the value if not.
             *
             * XXX - what's the difference between these cases?
             */
            if (sp->base_len &&
                (var->name_length < sp->base_len ||
                 snmp_oid_compare(var->name, sp->base_len, sp->base,
                                  sp->base_len) != 0)) {
                DEBUGMSGTL(( "proxy", "out of registered range... "));
                DEBUGMSGOID(("proxy", var->name, sp->base_len));
                DEBUGMSG((   "proxy", " (%d) != ", sp->base_len));
                DEBUGMSGOID(("proxy", sp->base, sp->base_len));
                DEBUGMSG((   "proxy", "\n"));
                snmp_set_var_typed_value(request->requestvb, ASN_NULL, NULL, 0);

                continue;
            } else if (!sp->base_len &&
                       (var->name_length < sp->name_len ||
                        snmp_oid_compare(var->name, sp->name_len, sp->name,
                                         sp->name_len) != 0)) {
                DEBUGMSGTL(( "proxy", "out of registered base range... "));
                DEBUGMSGOID(("proxy", var->name, sp->name_len));
                DEBUGMSG((   "proxy", " (%d) != ", sp->name_len));
                DEBUGMSGOID(("proxy", sp->name, sp->name_len));
                DEBUGMSG((   "proxy", "\n"));
                snmp_set_var_typed_value(request->requestvb, ASN_NULL, NULL, 0);
                continue;
            } else {
                /*
                 * If the returned OID is legitimate, then update
                 *   the original request varbind accordingly.
                 */
                if (sp->base_len) {
                    /*
                     * XXX: oid size maxed? 
                     */
                    memcpy(myname, sp->name, sizeof(oid) * sp->name_len);
                    myname_len =
                        sp->name_len + var->name_length - sp->base_len;
                    if (myname_len > MAX_OID_LEN) {
                        snmp_log(LOG_WARNING,
                                 "proxy OID return length too long.\n");
                        netsnmp_set_request_error(cache->reqinfo, requests,
                                                  SNMP_ERR_GENERR);
                        if (pdu)
                            snmp_free_pdu(pdu);
                        netsnmp_free_delegated_cache(cache);
                        return 1;
                    }

                    if (var->name_length > sp->base_len)
                        memcpy(&myname[sp->name_len],
                               &var->name[sp->base_len],
                               sizeof(oid) * (var->name_length -
                                              sp->base_len));
                    snmp_set_var_objid(request->requestvb, myname,
                                       myname_len);
                } else {
                    snmp_set_var_objid(request->requestvb, var->name,
                                       var->name_length);
                }
            }
        }

        if (request || var) {
            /*
             * ack, this is bad.  The # of varbinds don't match and
             * there is no way to fix the problem 
             */
            if (pdu)
                snmp_free_pdu(pdu);
            snmp_log(LOG_ERR,
                     "response to proxy request illegal.  We're screwed.\n");
            netsnmp_set_request_error(cache->reqinfo, requests,
                                      SNMP_ERR_GENERR);
        }

        /* fix bulk_to_next operations */
        if (cache->reqinfo->mode == MODE_GETBULK)
            netsnmp_bulk_to_next_fix_requests(requests);
        
        /*
         * free the response 
         */
        if (pdu && 0)
            snmp_free_pdu(pdu);
	break;

    default:
        DEBUGMSGTL(("proxy", "no response received: op = %d\n",
                    operation));
	break;
    }

    netsnmp_free_delegated_cache(cache);
    return 1;
}