/*
* baby_steps.c
* $Id$
*
* 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/agent/net-snmp-agent-includes.h>
netsnmp_feature_provide(baby_steps)
netsnmp_feature_child_of(baby_steps, mib_helpers)
#ifdef NETSNMP_FEATURE_REQUIRE_BABY_STEPS
netsnmp_feature_require(check_requests_error)
#endif
#ifndef NETSNMP_FEATURE_REMOVE_BABY_STEPS
#include <net-snmp/agent/baby_steps.h>
#define BABY_STEPS_PER_MODE_MAX 4
#define BSTEP_USE_ORIGINAL 0xffff
static u_short get_mode_map[BABY_STEPS_PER_MODE_MAX] = {
MODE_BSTEP_PRE_REQUEST, MODE_BSTEP_OBJECT_LOOKUP, BSTEP_USE_ORIGINAL, MODE_BSTEP_POST_REQUEST };
#ifndef NETSNMP_NO_WRITE_SUPPORT
static u_short set_mode_map[SNMP_MSG_INTERNAL_SET_MAX][BABY_STEPS_PER_MODE_MAX] = {
/*R1*/
{ MODE_BSTEP_PRE_REQUEST, MODE_BSTEP_OBJECT_LOOKUP, MODE_BSTEP_ROW_CREATE,
MODE_BSTEP_CHECK_VALUE },
/*R2*/
{ MODE_BSTEP_UNDO_SETUP, BABY_STEP_NONE, BABY_STEP_NONE, BABY_STEP_NONE },
/*A */
{ MODE_BSTEP_SET_VALUE,MODE_BSTEP_CHECK_CONSISTENCY,
MODE_BSTEP_COMMIT, BABY_STEP_NONE },
/*C */
{ MODE_BSTEP_IRREVERSIBLE_COMMIT, MODE_BSTEP_UNDO_CLEANUP, MODE_BSTEP_POST_REQUEST,
BABY_STEP_NONE},
/*F */
{ MODE_BSTEP_UNDO_CLEANUP, MODE_BSTEP_POST_REQUEST, BABY_STEP_NONE,
BABY_STEP_NONE },
/*U */
{ MODE_BSTEP_UNDO_COMMIT, MODE_BSTEP_UNDO_SET, MODE_BSTEP_UNDO_CLEANUP,
MODE_BSTEP_POST_REQUEST}
};
#endif /* NETSNMP_NO_WRITE_SUPPORT */
static int
_baby_steps_helper(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests);
static int
_baby_steps_access_multiplexer(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests);
/** @defgroup baby_steps baby_steps
* Calls your handler in baby_steps for set processing.
* @ingroup handler
* @{
*/
static netsnmp_baby_steps_modes *
netsnmp_baby_steps_modes_ref(netsnmp_baby_steps_modes *md)
{
md->refcnt++;
return md;
}
static void
netsnmp_baby_steps_modes_deref(netsnmp_baby_steps_modes *md)
{
if (--md->refcnt == 0)
free(md);
}
/** returns a baby_steps handler that can be injected into a given
* handler chain.
*/
netsnmp_mib_handler *
netsnmp_baby_steps_handler_get(u_long modes)
{
netsnmp_mib_handler *mh;
netsnmp_baby_steps_modes *md;
mh = netsnmp_create_handler("baby_steps", _baby_steps_helper);
if(!mh)
return NULL;
md = SNMP_MALLOC_TYPEDEF(netsnmp_baby_steps_modes);
if (NULL == md) {
snmp_log(LOG_ERR,"malloc failed in netsnmp_baby_steps_handler_get\n");
netsnmp_handler_free(mh);
mh = NULL;
}
else {
md->refcnt = 1;
mh->myvoid = md;
mh->data_clone = (void *(*)(void *))netsnmp_baby_steps_modes_ref;
mh->data_free = (void (*)(void *))netsnmp_baby_steps_modes_deref;
if (0 == modes)
modes = BABY_STEP_ALL;
md->registered = modes;
}
/*
* don't set MIB_HANDLER_AUTO_NEXT, since we need to call lower
* handlers with a munged mode.
*/
return mh;
}
/** @internal Implements the baby_steps handler */
static int
_baby_steps_helper(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
netsnmp_baby_steps_modes *bs_modes;
int save_mode, i, rc = SNMP_ERR_NOERROR;
u_short *mode_map_ptr;
DEBUGMSGTL(("baby_steps", "Got request, mode %s\n",
se_find_label_in_slist("agent_mode",reqinfo->mode)));
bs_modes = (netsnmp_baby_steps_modes*)handler->myvoid;
netsnmp_assert(NULL != bs_modes);
switch (reqinfo->mode) {
#ifndef NETSNMP_NO_WRITE_SUPPORT
case MODE_SET_RESERVE1:
/*
* clear completed modes
* xxx-rks: this will break for pdus with set requests to different
* rows in the same table when the handler is set up to use the row
* merge helper as well (or if requests are serialized).
*/
bs_modes->completed = 0;
/* FALL THROUGH */
case MODE_SET_RESERVE2:
case MODE_SET_ACTION:
case MODE_SET_COMMIT:
case MODE_SET_FREE:
case MODE_SET_UNDO:
mode_map_ptr = set_mode_map[reqinfo->mode];
break;
#endif /* NETSNMP_NO_WRITE_SUPPORT */
default:
/*
* clear completed modes
*/
bs_modes->completed = 0;
mode_map_ptr = get_mode_map;
}
/*
* NOTE: if you update this chart, please update the versions in
* local/mib2c-conf.d/parent-set.m2i
* agent/mibgroup/helpers/baby_steps.c
* while you're at it.
*/
/*
***********************************************************************
* Baby Steps Flow Chart (2004.06.05) *
* *
* +--------------+ +================+ U = unconditional path *
* |optional state| ||required state|| S = path for success *
* +--------------+ +================+ E = path for error *
***********************************************************************
*
* +--------------+
* | pre |
* | request |
* +--------------+
* | U
* +-------------+ +==============+
* | row |f|<-------|| object ||
* | create |1| E || lookup ||
* +-------------+ +==============+
* E | | S | S
* | +------------------>|
* | +==============+
* | E || check ||
* |<---------------|| values ||
* | +==============+
* | | S
* | +==============+
* | +<-------|| undo ||
* | | E || setup ||
* | | +==============+
* | | | S
* | | +==============+
* | | || set ||-------------------------->+
* | | || value || E |
* | | +==============+ |
* | | | S |
* | | +--------------+ |
* | | | check |-------------------------->|
* | | | consistency | E |
* | | +--------------+ |
* | | | S |
* | | +==============+ +==============+ |
* | | || commit ||-------->|| undo || |
* | | || || E || commit || |
* | | +==============+ +==============+ |
* | | | S U |<--------+
* | | +--------------+ +==============+
* | | | irreversible | || undo ||
* | | | commit | || set ||
* | | +--------------+ +==============+
* | | | U U |
* | +-------------->|<------------------------+
* | +==============+
* | || undo ||
* | || cleanup ||
* | +==============+
* +---------------------->| U
* |
* (err && f1)------------------->+
* | |
* +--------------+ +--------------+
* | post |<--------| row |
* | request | U | release |
* +--------------+ +--------------+
*
*/
/*
* save original mode
*/
save_mode = reqinfo->mode;
for(i = 0; i < BABY_STEPS_PER_MODE_MAX; ++i ) {
/*
* break if we run out of baby steps for this mode
*/
if(mode_map_ptr[i] == BABY_STEP_NONE)
break;
DEBUGMSGTL(("baby_steps", " baby step mode %s\n",
se_find_label_in_slist("babystep_mode",mode_map_ptr[i])));
/*
* skip modes the handler didn't register for
*/
if (BSTEP_USE_ORIGINAL != mode_map_ptr[i]) {
u_int mode_flag;
#ifndef NETSNMP_NO_WRITE_SUPPORT
/*
* skip undo commit if commit wasn't hit, and
* undo_cleanup if undo_setup wasn't hit.
*/
if((MODE_SET_UNDO == save_mode) &&
(MODE_BSTEP_UNDO_COMMIT == mode_map_ptr[i]) &&
!(BABY_STEP_COMMIT & bs_modes->completed)) {
DEBUGMSGTL(("baby_steps",
" skipping commit undo (no commit)\n"));
continue;
}
else if((MODE_SET_FREE == save_mode) &&
(MODE_BSTEP_UNDO_CLEANUP == mode_map_ptr[i]) &&
!(BABY_STEP_UNDO_SETUP & bs_modes->completed)) {
DEBUGMSGTL(("baby_steps",
" skipping undo cleanup (no undo setup)\n"));
continue;
}
#endif /* NETSNMP_NO_WRITE_SUPPORT */
reqinfo->mode = mode_map_ptr[i];
mode_flag = netsnmp_baby_step_mode2flag( mode_map_ptr[i] );
if((mode_flag & bs_modes->registered))
bs_modes->completed |= mode_flag;
else {
DEBUGMSGTL(("baby_steps",
" skipping mode (not registered)\n"));
continue;
}
}
else {
reqinfo->mode = save_mode;
}
#ifdef BABY_STEPS_NEXT_MODE
/*
* I can't remember why I wanted the next mode in the request,
* but it's not used anywhere, so don't use this code. saved,
* in case I remember why I thought needed it. - rstory 040911
*/
if((BABY_STEPS_PER_MODE_MAX - 1) == i)
reqinfo->next_mode_ok = BABY_STEP_NONE;
else {
if(BSTEP_USE_ORIGINAL == mode_map_ptr[i+1])
reqinfo->next_mode_ok = save_mode;
else
reqinfo->next_mode_ok = mode_map_ptr[i+1];
}
#endif
/*
* call handlers for baby step
*/
rc = netsnmp_call_next_handler(handler, reginfo, reqinfo,
requests);
/*
* check for error calling handler (unlikely, but...)
*/
if(rc) {
DEBUGMSGTL(("baby_steps", " ERROR:handler error\n"));
break;
}
/*
* check for errors in any of the requests for GET-like, reserve1,
* reserve2 and action. (there is no recovery from errors
* in commit, free or undo.)
*/
if (MODE_IS_GET(save_mode)
#ifndef NETSNMP_NO_WRITE_SUPPORT
|| (save_mode < SNMP_MSG_INTERNAL_SET_COMMIT)
#endif /* NETSNMP_NO_WRITE_SUPPORT */
) {
rc = netsnmp_check_requests_error(requests);
if(rc) {
DEBUGMSGTL(("baby_steps", " ERROR:request error\n"));
break;
}
}
}
/*
* restore original mode
*/
reqinfo->mode = save_mode;
return rc;
}
/** initializes the baby_steps helper which then registers a baby_steps
* handler as a run-time injectable handler for configuration file
* use.
*/
netsnmp_feature_child_of(netsnmp_baby_steps_handler_init,netsnmp_unused)
#ifndef NETSNMP_FEATURE_REMOVE_NETSNMP_BABY_STEPS_HANDLER_INIT
void
netsnmp_baby_steps_handler_init(void)
{
netsnmp_mib_handler *handler =
netsnmp_baby_steps_handler_get(BABY_STEP_ALL);
if (NULL == handler) {
netsnmp_handler_free(handler);
snmp_log(LOG_ERR, "could not create baby steps handler\n");
return;
}
netsnmp_register_handler_by_name("baby_steps", handler);
}
#endif /* NETSNMP_FEATURE_REMOVE_NETSNMP_BABY_STEPS_HANDLER_INIT */
/** @} */
/** @defgroup access_multiplexer baby_steps_access_multiplexer: calls individual access methods based on baby_step mode.
* @ingroup baby_steps
* @{
*/
/** returns a baby_steps handler that can be injected into a given
* handler chain.
*/
netsnmp_mib_handler *
netsnmp_baby_steps_access_multiplexer_get(netsnmp_baby_steps_access_methods *am)
{
netsnmp_mib_handler *mh;
mh = netsnmp_create_handler("baby_steps_mux",
_baby_steps_access_multiplexer);
if(!mh)
return NULL;
mh->myvoid = am;
mh->flags |= MIB_HANDLER_AUTO_NEXT;
return mh;
}
/** @internal Implements the baby_steps handler */
static int
_baby_steps_access_multiplexer(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
void *temp_void;
Netsnmp_Node_Handler *method = NULL;
netsnmp_baby_steps_access_methods *access_methods;
int rc = SNMP_ERR_NOERROR;
/** call handlers should enforce these */
netsnmp_assert((handler!=NULL) && (reginfo!=NULL) && (reqinfo!=NULL) &&
(requests!=NULL));
DEBUGMSGT(("baby_steps_mux", "mode %s\n",
se_find_label_in_slist("babystep_mode",reqinfo->mode)));
access_methods = (netsnmp_baby_steps_access_methods *)handler->myvoid;
if(!access_methods) {
snmp_log(LOG_ERR,"baby_steps_access_multiplexer has no methods\n");
return SNMPERR_GENERR;
}
switch(reqinfo->mode) {
case MODE_BSTEP_PRE_REQUEST:
if( access_methods->pre_request )
method = access_methods->pre_request;
break;
case MODE_BSTEP_OBJECT_LOOKUP:
if( access_methods->object_lookup )
method = access_methods->object_lookup;
break;
case SNMP_MSG_GET:
case SNMP_MSG_GETNEXT:
if( access_methods->get_values )
method = access_methods->get_values;
break;
#ifndef NETSNMP_NO_WRITE_SUPPORT
case MODE_BSTEP_CHECK_VALUE:
if( access_methods->object_syntax_checks )
method = access_methods->object_syntax_checks;
break;
case MODE_BSTEP_ROW_CREATE:
if( access_methods->row_creation )
method = access_methods->row_creation;
break;
case MODE_BSTEP_UNDO_SETUP:
if( access_methods->undo_setup )
method = access_methods->undo_setup;
break;
case MODE_BSTEP_SET_VALUE:
if( access_methods->set_values )
method = access_methods->set_values;
break;
case MODE_BSTEP_CHECK_CONSISTENCY:
if( access_methods->consistency_checks )
method = access_methods->consistency_checks;
break;
case MODE_BSTEP_UNDO_SET:
if( access_methods->undo_sets )
method = access_methods->undo_sets;
break;
case MODE_BSTEP_COMMIT:
if( access_methods->commit )
method = access_methods->commit;
break;
case MODE_BSTEP_UNDO_COMMIT:
if( access_methods->undo_commit )
method = access_methods->undo_commit;
break;
case MODE_BSTEP_IRREVERSIBLE_COMMIT:
if( access_methods->irreversible_commit )
method = access_methods->irreversible_commit;
break;
case MODE_BSTEP_UNDO_CLEANUP:
if( access_methods->undo_cleanup )
method = access_methods->undo_cleanup;
break;
#endif /* NETSNMP_NO_WRITE_SUPPORT */
case MODE_BSTEP_POST_REQUEST:
if( access_methods->post_request )
method = access_methods->post_request;
break;
default:
snmp_log(LOG_ERR,"unknown mode %d\n", reqinfo->mode);
return SNMP_ERR_GENERR;
}
/*
* if method exists, set up handler void and call method.
*/
if(NULL != method) {
temp_void = handler->myvoid;
handler->myvoid = access_methods->my_access_void;
rc = (*method)(handler, reginfo, reqinfo, requests);
handler->myvoid = temp_void;
}
else {
rc = SNMP_ERR_GENERR;
snmp_log(LOG_ERR,"baby steps multiplexer handler called for a mode "
"with no handler\n");
netsnmp_assert(NULL != method);
}
/*
* don't call any lower handlers, it will be done for us
* since we set MIB_HANDLER_AUTO_NEXT
*/
return rc;
}
/*
* give a baby step mode, return the flag for that mode
*/
int
netsnmp_baby_step_mode2flag( u_int mode )
{
switch( mode ) {
case MODE_BSTEP_OBJECT_LOOKUP:
return BABY_STEP_OBJECT_LOOKUP;
#ifndef NETSNMP_NO_WRITE_SUPPORT
case MODE_BSTEP_SET_VALUE:
return BABY_STEP_SET_VALUE;
case MODE_BSTEP_IRREVERSIBLE_COMMIT:
return BABY_STEP_IRREVERSIBLE_COMMIT;
case MODE_BSTEP_CHECK_VALUE:
return BABY_STEP_CHECK_VALUE;
case MODE_BSTEP_PRE_REQUEST:
return BABY_STEP_PRE_REQUEST;
case MODE_BSTEP_POST_REQUEST:
return BABY_STEP_POST_REQUEST;
case MODE_BSTEP_UNDO_SETUP:
return BABY_STEP_UNDO_SETUP;
case MODE_BSTEP_UNDO_CLEANUP:
return BABY_STEP_UNDO_CLEANUP;
case MODE_BSTEP_UNDO_SET:
return BABY_STEP_UNDO_SET;
case MODE_BSTEP_ROW_CREATE:
return BABY_STEP_ROW_CREATE;
case MODE_BSTEP_CHECK_CONSISTENCY:
return BABY_STEP_CHECK_CONSISTENCY;
case MODE_BSTEP_COMMIT:
return BABY_STEP_COMMIT;
case MODE_BSTEP_UNDO_COMMIT:
return BABY_STEP_UNDO_COMMIT;
#endif /* NETSNMP_NO_WRITE_SUPPORT */
default:
netsnmp_assert("unknown flag");
break;
}
return 0;
}
/** @} */
#else /* NETSNMP_FEATURE_REMOVE_BABY_STEPS */
netsnmp_feature_unused(baby_steps);
#endif /* NETSNMP_FEATURE_REMOVE_BABY_STEPS */