/*
* DisMan Expression MIB:
* Implementation of the expValueTable MIB interface
* See 'expValue.c' for active evaluation of expressions.
*
* (Based roughly on mib2c.raw-table.conf output)
*/
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include "expValue.h"
#include "expValueTable.h"
/** Initializes the expValueTable module */
void
init_expValueTable(void)
{
static oid expValueTable_oid[] = { 1, 3, 6, 1, 2, 1, 90, 1, 3, 1 };
size_t expValueTable_oid_len = OID_LENGTH(expValueTable_oid);
netsnmp_handler_registration *reg;
netsnmp_table_registration_info *table_info;
reg =
netsnmp_create_handler_registration("expValueTable",
expValueTable_handler,
expValueTable_oid,
expValueTable_oid_len,
HANDLER_CAN_RONLY);
table_info = SNMP_MALLOC_TYPEDEF(netsnmp_table_registration_info);
netsnmp_table_helper_add_indexes(table_info,
ASN_OCTET_STR, /* expExpressionOwner */
ASN_OCTET_STR, /* expExpressionName */
/* expValueInstance */
ASN_PRIV_IMPLIED_OBJECT_ID,
0);
table_info->min_column = COLUMN_EXPVALUECOUNTER32VAL;
table_info->max_column = COLUMN_EXPVALUECOUNTER64VAL;
netsnmp_register_table(reg, table_info);
DEBUGMSGTL(("disman:expr:init", "Expression Value Table\n"));
}
netsnmp_variable_list *
expValueTable_getEntry(netsnmp_variable_list * indexes,
int mode, unsigned int colnum)
{
struct expExpression *exp;
netsnmp_variable_list *res, *vp, *vp2;
oid nullInstance[] = {0, 0, 0};
int plen;
size_t len;
unsigned int type = colnum-1; /* column object subIDs and type
enumerations are off by one. */
if (!indexes || !indexes->next_variable ||
!indexes->next_variable->next_variable ) {
/* XXX - Shouldn't happen! */
return NULL;
}
DEBUGMSGTL(( "disman:expr:val", "get (%d) entry (%s, %s, ", mode,
indexes->val.string, indexes->next_variable->val.string));
DEBUGMSGOID(("disman:expr:val",
indexes->next_variable->next_variable->val.objid,
indexes->next_variable->next_variable->val_len/sizeof(oid)));
DEBUGMSG(( "disman:expr:val", ")\n"));
/*
* Locate the expression that we've been asked to evaluate
*/
if (!indexes->val_len || !indexes->next_variable->val_len ) {
/*
* Incomplete expression specification
*/
if (mode == MODE_GETNEXT || mode == MODE_GETBULK) {
exp = expExpression_getFirstEntry();
DEBUGMSGTL(( "disman:expr:val", "first entry (%p)\n", exp ));
} else {
DEBUGMSGTL(( "disman:expr:val", "incomplete request\n" ));
return NULL; /* No match */
}
} else {
exp = expExpression_getEntry( (char*)indexes->val.string,
(char*)indexes->next_variable->val.string);
DEBUGMSGTL(( "disman:expr:val", "using entry (%p)\n", exp ));
}
/*
* We know what type of value was requested,
* so ignore any non-matching expressions.
*/
while (exp && exp->expValueType != type) {
if (mode != MODE_GETNEXT && mode != MODE_GETBULK) {
DEBUGMSGTL(( "disman:expr:val", "wrong type (%d != %ld)\n",
type, (exp ? exp->expValueType : 0 )));
return NULL; /* Wrong type */
}
NEXT_EXP:
exp = expExpression_getNextEntry( exp->expOwner, exp->expName );
DEBUGMSGTL(( "disman:expr:val", "using next entry (%p)\n", exp ));
}
if (!exp) {
DEBUGMSGTL(( "disman:expr:val", "no more entries\n"));
return NULL; /* No match (of the required type) */
}
/*
* Now consider which instance of the chosen expression is needed
*/
vp = indexes->next_variable->next_variable;
if ( mode == MODE_GET ) {
/*
* For a GET request, check that the specified value instance
* is valid, and evaluate the expression using this.
*/
if ( !vp || !vp->val_len ) {
DEBUGMSGTL(( "disman:expr:val", "no instance index\n"));
return NULL; /* No instance provided */
}
if ( vp->val.objid[0] != 0 ) {
DEBUGMSGTL(( "disman:expr:val",
"non-zero instance (%" NETSNMP_PRIo "d)\n", vp->val.objid[0]));
return NULL; /* Invalid instance */
}
if (exp->expPrefix_len == 0 ) {
/*
* The only valid instance for a non-wildcarded
* expression is .0.0.0
*/
if ( vp->val_len != 3*sizeof(oid) ||
vp->val.objid[1] != 0 ||
vp->val.objid[2] != 0 ) {
DEBUGMSGTL(( "disman:expr:val", "invalid scalar instance\n"));
return NULL;
}
res = expValue_evaluateExpression( exp, NULL, 0 );
DEBUGMSGTL(( "disman:expr:val", "scalar get returned (%p)\n", res));
} else {
/*
* Otherwise, skip the leading '.0' and use
* the remaining instance subidentifiers.
*/
res = expValue_evaluateExpression( exp, vp->val.objid+1,
vp->val_len/sizeof(oid)-1);
DEBUGMSGTL(( "disman:expr:val", "w/card get returned (%p)\n", res));
}
} else {
/*
* For a GETNEXT request, identify the appropriate next
* value instance, and evaluate the expression using
* that, updating the index list appropriately.
*/
if ( vp->val_len > 0 && vp->val.objid[0] != 0 ) {
DEBUGMSGTL(( "disman:expr:val",
"non-zero next instance (%" NETSNMP_PRIo "d)\n", vp->val.objid[0]));
return NULL; /* All valid instances start with .0 */
}
plen = exp->expPrefix_len;
if (plen == 0 ) {
/*
* The only valid instances for GETNEXT on a
* non-wildcarded expression are .0 and .0.0
* Anything else is too late.
*/
if ((vp->val_len > 2*sizeof(oid)) ||
(vp->val_len == 2*sizeof(oid) &&
vp->val.objid[1] != 0)) {
DEBUGMSGTL(( "disman:expr:val", "invalid scalar next instance\n"));
return NULL; /* Invalid instance */
}
/*
* Make sure the index varbind list refers to the
* (only) valid instance of this expression,
* and evaluate it.
*/
snmp_set_var_typed_value( indexes, ASN_OCTET_STR,
(u_char*)exp->expOwner, strlen(exp->expOwner));
snmp_set_var_typed_value( indexes->next_variable, ASN_OCTET_STR,
(u_char*)exp->expName, strlen(exp->expName));
snmp_set_var_typed_value( vp, ASN_PRIV_IMPLIED_OBJECT_ID,
(u_char*)nullInstance, 3*sizeof(oid));
res = expValue_evaluateExpression( exp, NULL, 0 );
DEBUGMSGTL(( "disman:expr:val", "scalar next returned (%p)\n", res));
} else {
/*
* Now comes the interesting case - finding the
* appropriate instance of a wildcarded expression.
*/
if ( vp->val_len == 0 ) {
if ( !exp->pvars ) {
DEBUGMSGTL(( "disman:expr:val", "no instances\n"));
goto NEXT_EXP;
}
DEBUGMSGTL(( "disman:expr:val", "using first instance\n"));
vp2 = exp->pvars;
} else {
/*
* Search the list of instances for the (first) greater one
* XXX - This comparison relies on the OID of the prefix
* object being the same length as the wildcarded
* parameter objects. It ain't necessarily so.
*/
for ( vp2 = exp->pvars; vp2; vp2 = vp2->next_variable ) {
if ( snmp_oid_compare( vp2->name + plen,
vp2->name_length - plen,
vp->name,
vp->name_length) < 0 ) {
DEBUGMSGTL(( "disman:expr:val", "next instance "));
DEBUGMSGOID(("disman:expr:val", vp2->name, vp2->name_length ));
DEBUGMSG(( "disman:expr:val", "\n"));
break;
}
}
if (!vp2) {
DEBUGMSGTL(( "disman:expr:val", "no next instance\n"));
goto NEXT_EXP;
}
}
snmp_set_var_typed_value( indexes, ASN_OCTET_STR,
(u_char*)exp->expOwner, strlen(exp->expOwner));
snmp_set_var_typed_value( indexes->next_variable, ASN_OCTET_STR,
(u_char*)exp->expName, strlen(exp->expName));
if (vp2) {
len = vp2->name_length - exp->expPrefix_len;
snmp_set_var_typed_value( vp, ASN_PRIV_IMPLIED_OBJECT_ID,
(u_char*)(vp2->name+exp->expPrefix_len), len);
} else {
len = 1;
}
res = expValue_evaluateExpression( exp, vp->val.objid+1, len-1);
DEBUGMSGTL(( "disman:expr:val", "w/card next returned (%p)\n", res));
}
}
return res;
}
/** handles requests for the expValueTable table */
int
expValueTable_handler(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
netsnmp_request_info *request;
netsnmp_table_request_info *tinfo;
netsnmp_variable_list *value;
oid expValueOID[] = { 1, 3, 6, 1, 2, 1, 90, 1, 3, 1, 1, 99 };
size_t expValueOID_len = OID_LENGTH(expValueOID);
oid name_buf[ MAX_OID_LEN ];
size_t name_buf_len = MAX_OID_LEN;
DEBUGMSGTL(("disman:expr:mib", "Expression Value Table handler (%d)\n",
reqinfo->mode));
switch (reqinfo->mode) {
case MODE_GET:
case MODE_GETNEXT:
for (request = requests; request; request = request->next) {
tinfo = netsnmp_extract_table_info(request);
value = expValueTable_getEntry(tinfo->indexes,
reqinfo->mode,
tinfo->colnum);
if (!value || !value->val.integer) {
netsnmp_set_request_error(reqinfo, request,
(reqinfo->mode == MODE_GET) ?
SNMP_NOSUCHINSTANCE :
SNMP_ENDOFMIBVIEW);
continue;
}
if ( reqinfo->mode == MODE_GETNEXT ) {
/*
* Need to update the request varbind OID
* to match the instance just evaluated.
* (XXX - Is this the appropriate mechanism?)
*/
build_oid_noalloc( name_buf, MAX_OID_LEN, &name_buf_len,
expValueOID, expValueOID_len, tinfo->indexes );
name_buf[ expValueOID_len -1 ] = tinfo->colnum;
snmp_set_var_objid(request->requestvb, name_buf, name_buf_len);
}
switch (tinfo->colnum) {
case COLUMN_EXPVALUECOUNTER32VAL:
snmp_set_var_typed_integer(request->requestvb, ASN_COUNTER,
*value->val.integer);
break;
case COLUMN_EXPVALUEUNSIGNED32VAL:
snmp_set_var_typed_integer(request->requestvb, ASN_UNSIGNED,
*value->val.integer);
break;
case COLUMN_EXPVALUETIMETICKSVAL:
snmp_set_var_typed_integer(request->requestvb, ASN_TIMETICKS,
*value->val.integer);
break;
case COLUMN_EXPVALUEINTEGER32VAL:
snmp_set_var_typed_integer(request->requestvb, ASN_INTEGER,
*value->val.integer);
break;
case COLUMN_EXPVALUEIPADDRESSVAL:
snmp_set_var_typed_integer(request->requestvb, ASN_IPADDRESS,
*value->val.integer);
break;
case COLUMN_EXPVALUEOCTETSTRINGVAL:
snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,
value->val.string, value->val_len);
break;
case COLUMN_EXPVALUEOIDVAL:
snmp_set_var_typed_value( request->requestvb, ASN_OBJECT_ID,
(u_char *)value->val.objid, value->val_len);
break;
case COLUMN_EXPVALUECOUNTER64VAL:
snmp_set_var_typed_value( request->requestvb, ASN_COUNTER64,
(u_char *)value->val.counter64, value->val_len);
break;
}
/* remember to free the variable list, or we will leak here.. */
snmp_free_varbind(value);
}
break;
}
DEBUGMSGTL(("disman:expr:mib", "Expression Value handler - done \n"));
return SNMP_ERR_NOERROR;
}