clixon/apps/snmp/snmp_mib_yang.c
Olof hagsand 1f8b82e8e1 SNMP frontend, add int32 + string type for scalars
Added get string test
Added set value for netconf test
2022-06-26 11:28:42 +02:00

695 lines
20 KiB
C

/*
*
***** BEGIN LICENSE BLOCK *****
Copyright (C) 2022 Olof Hagsand and Kristofer Hallin
This file is part of CLIXON.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Alternatively, the contents of this file may be used under the terms of
the GNU General Public License Version 3 or later (the "GPL"),
in which case the provisions of the GPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of the GPL, and not to allow others to
use your version of this file under the terms of Apache License version 2,
indicate your decision by deleting the provisions above and replace them with
the notice and other provisions required by the GPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the Apache License version 2 or the GPL.
***** END LICENSE BLOCK *****
* See RFC 6643
* Extensions are grouped in some categories, the one I have seen are, example:
* 1. leaf
* smiv2:max-access "read-write";
* smiv2:oid "1.3.6.1.4.1.8072.2.1.1";
* smiv2:defval "42"; (not always)
* 2. container, list
* smiv2:oid "1.3.6.1.4.1.8072.2.1";
* 3. module level
* smiv2:alias "netSnmpExamples" {
* smiv2:oid "1.3.6.1.4.1.8072.2";
*
*/
#ifdef HAVE_CONFIG_H
#include "clixon_config.h" /* generated by config & autoconf */
#endif
#include <stdio.h>
#include <unistd.h>
#include <pwd.h>
#include <syslog.h>
#include <errno.h>
#include <sys/types.h>
#include <signal.h>
/* net-snmp */
#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
/* cligen */
#include <cligen/cligen.h>
/* clicon */
#include <clixon/clixon.h>
#include "snmp_mib_yang.h"
#define IETF_YANG_SMIV2_NS "urn:ietf:params:xml:ns:yang:ietf-yang-smiv2"
/*
* Local Types
*/
/* Userdata to pass around in netsmp callbacks
*/
struct clixon_snmp_handle {
clicon_handle sh_h;
yang_stmt *sh_ys;
char *sh_default;
};
typedef struct clixon_snmp_handle clixon_snmp_handle;
/*
* Local variables
*/
/* Mapping between yang keyword string <--> clixon constants
* Here is also the place where doc on some types store variables (cv)
*/
/* Mapping between smiv2 yang extension access string string <--> netsnmp handler codes (agent_handler.h)
* Here is also the place where doc on some types store variables (cv)
* see netsnmp_handler_registration_create()
*/
static const map_str2int snmp_access_map[] = {
{"read-only", HANDLER_CAN_RONLY}, /* HANDLER_CAN_GETANDGETNEXT */
{"read-write", HANDLER_CAN_RWRITE}, /* HANDLER_CAN_GETANDGETNEXT | HANDLER_CAN_SET */
{"not-accessible", 0}, // XXX
{"accessible-for-notify", 0}, // XXX
{NULL, -1}
};
/* Map between clixon and ASN.1 types.
* @see net-snmp/library/asn1.h
* @see union netsnmp_vardata in net-snmp/types.h
*/
static const map_str2int snmp_type_map[] = {
{"bool", ASN_BOOLEAN},
{"int32", ASN_INTEGER},
{"bits", ASN_BIT_STR},
{"string", ASN_OCTET_STR},
{"empty", ASN_NULL},
//XXX {"", ASN_OBJECT_ID},
// XXX {"", ASN_SEQUENCE},
// XXX {"", ASN_SET},
{NULL, -1}
};
static int
yang2snmp_types(yang_stmt *ys,
int *asn1_type,
enum cv_type *cvtype)
{
int retval = -1;
yang_stmt *yrestype; /* resolved type */
char *restype; /* resolved type */
char *origtype=NULL; /* original type */
/* Get yang type of leaf and trasnslate to ASN.1 */
if (yang_type_get(ys, &origtype, &yrestype, NULL, NULL, NULL, NULL, NULL) < 0)
goto done;
restype = yrestype?yang_argument_get(yrestype):NULL;
if (clicon_type2cv(origtype, restype, ys, cvtype) < 0)
goto done;
/* translate to asn.1 */
*asn1_type = clicon_str2int(snmp_type_map, restype);
clicon_debug(1, "%s type:%s", __FUNCTION__, restype);
retval = 0;
done:
return retval;
}
#if 1 /* table example */
/*
* https://net-snmp.sourceforge.io/dev/agent/data_set_8c-example.html#_a0
*/
int
table_handler(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
netsnmp_table_data_set *table = (netsnmp_table_data_set *)reginfo->my_reg_void;
netsnmp_table_row *row;
row = netsnmp_create_table_data_row();
netsnmp_table_row_add_index(row, ASN_OCTET_STR, "snmpv3", strlen("snmpv3"));
netsnmp_set_row_column(row, 2, ASN_OCTET_STR, "Russ Mundy", strlen("Russ Mundy"));
netsnmp_mark_row_column_writable(row, 2, 1);
netsnmp_set_row_column(row, 3, ASN_OCTET_STR, "David Harrington", strlen("David Harrington"));
netsnmp_mark_row_column_writable(row, 3, 1);
netsnmp_table_dataset_add_row(table, row);
return SNMP_ERR_NOERROR;
}
static void
init_testtable(void)
{
netsnmp_handler_registration *handler;
netsnmp_table_data_set *table;
oid my_registration_oid[] = { 1, 3, 6, 1, 4, 1, 8072, 2, 2, 1 };
netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_X_SOCKET, "/var/run/snmp.sock");
table = netsnmp_create_table_data_set("netSnmpIETFWGTable");
netsnmp_table_dataset_add_index(table, ASN_OCTET_STR);
netsnmp_table_set_multi_add_default_row(table, 2, ASN_OCTET_STR, 1, NULL, 0, 3, ASN_OCTET_STR, 1, NULL, 0, 0);
handler = netsnmp_create_handler_registration("netSnmpIETFWGTable", table_handler,
my_registration_oid,
OID_LENGTH(my_registration_oid),
HANDLER_CAN_RWRITE);
handler->my_reg_void = table;
netsnmp_register_table_data_set(handler, table, NULL);
netsnmp_register_auto_data_table(table, NULL);
}
#endif /* table example */
/*! Construct an xpath from yang statement
* Recursively construct it to the top.
* @param[in] ys Yang statement
* @param[out] cb xpath as cbuf
* @retval 0 OK
* @retval -1 Error
* XXX Not lists
*/
static int
yang2xpath(yang_stmt *ys,
cbuf *cb)
{
yang_stmt *yp; /* parent */
int i;
cvec *cvk = NULL; /* vector of index keys */
int retval = -1;
if ((yp = yang_parent_get(ys)) == NULL){
clicon_err(OE_YANG, EINVAL, "yang expected parent %s", yang_argument_get(ys));
goto done;
}
if (yp != NULL && /* XXX rm */
yang_keyword_get(yp) != Y_MODULE &&
yang_keyword_get(yp) != Y_SUBMODULE){
if (yang2xpath(yp, cb) < 0) /* recursive call */
goto done;
if (yang_keyword_get(yp) != Y_CHOICE && yang_keyword_get(yp) != Y_CASE){
cprintf(cb, "/");
}
}
cprintf(cb, "/%s:", yang_find_myprefix(ys));
if (yang_keyword_get(ys) != Y_CHOICE && yang_keyword_get(ys) != Y_CASE)
cprintf(cb, "%s", yang_argument_get(ys));
switch (yang_keyword_get(ys)){
case Y_LIST: // XXX not xpaths
cvk = yang_cvec_get(ys); /* Use Y_LIST cache, see ys_populate_list() */
if (cvec_len(cvk))
cprintf(cb, "=");
/* Iterate over individual keys */
for (i=0; i<cvec_len(cvk); i++){
if (i)
cprintf(cb, ",");
cprintf(cb, "%%s");
}
break;
case Y_LEAF_LIST:
cprintf(cb, "=%%s");
break;
default:
break;
} /* switch */
retval = 0;
done:
return retval;
}
/*! Translate from yang/xml/clixon to SNMP/ASN.1
**
* The tran
* @param[in] valstr Clixon/yang/xml string value
* @param[in] cvtype Type of clixon type
* @param[out] snmpval Malloc:ed snmp type
* @param[out] snmplen Length of snmp type
* @retval 1 OK
* @retval 0 Invalid value
* @retval -1 Error
*/
static int
type_yang2snmp(char *valstr,
enum cv_type cvtype,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests,
u_char **snmpval,
size_t *snmplen)
{
int retval = -1;
int ret;
char *reason = NULL;
size_t cvlen;
cg_var *cv;
clicon_debug(1, "%s", __FUNCTION__);
if (snmpval == NULL || snmplen == NULL){
clicon_err(OE_UNIX, EINVAL, "snmpval or snmplen is NULL");
goto done;
}
if ((cv = cv_new(cvtype)) == NULL){
clicon_err(OE_UNIX, errno, "cv_new");
goto done;
}
if ((ret = cv_parse1(valstr, cv, &reason)) < 0)
goto done;
if (ret == 0){
clicon_debug(1, "%s %s", __FUNCTION__, reason);
netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_WRONGTYPE);
goto fail;
}
cvlen = cv_len(cv);
if ((*snmpval = malloc(cvlen)) == NULL){
clicon_err(OE_UNIX, errno, "malloc");
goto done;
}
switch (cvtype){
case CGV_INT32:{
int i = cv_int32_get(cv);
memcpy(*snmpval, &i, cvlen);
*snmplen = cvlen;
break;
}
case CGV_STRING:{
strcpy(*snmpval, cv_string_get(cv));
*snmplen = cvlen;
break;
}
default:
clicon_debug(1, "%s %s not supported", __FUNCTION__, cv_type2str(cvtype));
netsnmp_set_request_error(reqinfo, requests, SNMP_ERR_WRONGTYPE);
goto fail;
break;
}
retval = 1;
done:
clicon_debug(1, "%s %d", __FUNCTION__, retval);
if (reason)
free(reason);
return retval;
fail:
retval = 0;
goto done;
}
/*! SNMP Scalar operation handler
* Calls come: READ:160,
* WRITE: 0, 1, 2, 3,
* MODE_SET_RESEVE1, MODE_SET_RESERVE2, MODE_SET_ACTION, MODE_SET_COMMIT
*
*/
int
snmp_scalar_handler(netsnmp_mib_handler *handler,
netsnmp_handler_registration *reginfo,
netsnmp_agent_request_info *reqinfo,
netsnmp_request_info *requests)
{
int retval = -1;
clixon_snmp_handle *sh;
yang_stmt *ys;
clicon_handle h;
cbuf *cb = NULL;
cg_var *cv = NULL;
cxobj *xt = NULL;
cxobj *xerr;
cvec *nsc = NULL;
cxobj *x;
char *xpath;
int asn1_type;
enum cv_type cvtype;
char *valstr;
u_char *snmpval = NULL;
size_t snmplen;
int ret;
/*
* can be used to pass information on a per-pdu basis from a
* helper to the later handlers
netsnmp_agent_request_info *reqinfo,
netsnmp_data_list *agent_data;
netsnmp_free_agent_data_set()
*/
clicon_debug(1, "%s %s", __FUNCTION__, handler->handler_name);
sh = (clixon_snmp_handle*)handler->myvoid;
ys = sh->sh_ys;
h = sh->sh_h;
clicon_debug(1, "%s mode:%d", __FUNCTION__, reqinfo->mode);
if (yang2snmp_types(ys, &asn1_type, &cvtype) < 0)
goto done;
/* see net-snmp/agent/snmp_agent.h / net-snmp/library/snmp.h */
switch (reqinfo->mode) {
case MODE_GET: // 160
requests->requestvb->type = asn1_type; // ASN_NULL on input
/* get xpath: see yang2api_path_fmt / api_path2xpath
New fn: yang2xpath?
clicon_rpc_get()
<rpc $DEFAULTNS><get><filter type=\"xpath\" select=\"/if:interfaces\" xmlns:if=\"urn:ietf:params:xml:ns:yang:ietf-interfaces\" /></get></rpc>"
*/
if (xml_nsctx_yang(ys, &nsc) < 0)
goto done;
if ((cb = cbuf_new()) == NULL){
clicon_err(OE_UNIX, errno, "cbuf_new");
goto done;
}
if (yang2xpath(ys, cb) < 0)
goto done;
xpath = cbuf_get(cb);
if (clicon_rpc_get(h, xpath, nsc, CONTENT_ALL, -1, &xt) < 0)
goto done;
if ((xerr = xpath_first(xt, NULL, "/rpc-error")) != NULL){
clixon_netconf_error(xerr, "clicon_rpc_get", NULL);
goto done;
}
/* Get value, either from xml, or smiv2 default */
if ((x = xpath_first(xt, nsc, "%s", xpath)) != NULL) {
valstr = xml_body(x);
}
else if ((valstr = sh->sh_default) != NULL)
;
else
valstr = "0"; // XXX table calls leafs with no value?
if ((ret = type_yang2snmp(valstr, cvtype, reqinfo, requests, &snmpval, &snmplen)) < 0)
goto done;
if (ret == 0)
goto ok;
/* 1. use cligen object and get rwa buf / size from that, OR
* + have parse function from YANG
* - does not have
* 2. use union netsnmp_vardata and pass that here?
* 3. Make cv2asn1 conversion function <--
*/
/* see snmplib/snmp_client.c */
if (snmp_set_var_value(requests->requestvb,
snmpval,
snmplen) != 0){
clicon_err(OE_SNMP, 0, "snmp_set_var_value");
goto done;
}
break;
case MODE_SET_RESERVE1: // 0
if (requests->requestvb->type != asn1_type)
netsnmp_set_request_error(reqinfo, requests,
SNMP_ERR_WRONGTYPE);
break;
case MODE_SET_RESERVE2: // 1
break;
case MODE_SET_ACTION: // 2
/*
* update current
*/
/* yang2xpath -> xpath2xml
* accesses = *(requests->requestvb->val.integer);
* rpc edit-config
<data></data>
*/
if ((cb = cbuf_new()) == NULL){
clicon_err(OE_UNIX, errno, "cbuf_new");
goto done;
}
cprintf(cb, "<config><NET-SNMP-EXAMPLES-MIB xmlns=\"urn:ietf:params:xml:ns:yang:smiv2:NET-SNMP-EXAMPLES-MIB\"><netSnmpExampleScalars><netSnmpExampleInteger>%ld</netSnmpExampleInteger></netSnmpExampleScalars></NET-SNMP-EXAMPLES-MIB></config>", *requests->requestvb->val.integer);
if (clicon_rpc_edit_config(h, "candidate", OP_MERGE, cbuf_get(cb)) < 0)
goto done;
break;
case MODE_SET_UNDO: // 5
if (clicon_rpc_discard_changes(h) < 0)
goto done;
break;
case MODE_SET_COMMIT: // 3
if (clicon_rpc_commit(h) < 0)
goto done;
break;
case MODE_SET_FREE: // 4
/*
* nothing to do
*/
break;
}
ok:
retval = SNMP_ERR_NOERROR;
done:
if (snmpval)
free(snmpval);
if (xt)
xml_free(xt);
if (nsc)
xml_nsctx_free(nsc);
if (cv)
cv_free(cv);
if (cb)
cbuf_free(cb);
return retval;
}
/*! Parse smiv2 extensions for YANG leaf
* Typical leaf:
* smiv2:oid "1.3.6.1.4.1.8072.2.1.1";
* smiv2:max-access "read-write";
* smiv2:defval "42"; (optional)
*/
static int
mib_yang_leaf(clicon_handle h,
yang_stmt *ys)
{
int retval = -1;
netsnmp_handler_registration *nh = NULL;
netsnmp_mib_handler *handler;
int ret;
char *oidstr = NULL;
char *modes_str = NULL;
char *default_str = NULL;
oid oid1[MAX_OID_LEN] = {0,};
size_t sz1 = MAX_OID_LEN;
int modes;
char *name;
clixon_snmp_handle *sh;
if (yang_extension_value(ys, "oid", IETF_YANG_SMIV2_NS, NULL, &oidstr) < 0)
goto done;
if (oidstr == NULL)
goto ok;
if (snmp_parse_oid(oidstr, oid1, &sz1) == NULL){
clicon_err(OE_SNMP, 0, "snmp_parse_oid");
goto done;
}
if (yang_extension_value(ys, "max-access", IETF_YANG_SMIV2_NS, NULL, &modes_str) < 0)
goto done;
/* Get modes (access) read-only, read-write, not-accessible, oaccessible-for-notify
*/
if (modes_str == NULL)
goto ok;
modes = clicon_str2int(snmp_access_map, modes_str);
/* SMI default value, How is this different from yang defaults?
*/
if (yang_extension_value(ys, "defval", IETF_YANG_SMIV2_NS, NULL, &default_str) < 0)
goto done;
name = yang_argument_get(ys);
if ((handler = netsnmp_create_handler(name, snmp_scalar_handler)) == NULL){
clicon_err(OE_SNMP, errno, "netsnmp_create_handler");
goto done;
}
/* Userdata to pass around in netsmp callbacks
* XXX: not deallocated
*/
if ((sh = malloc(sizeof(*sh))) == NULL){
clicon_err(OE_UNIX, errno, "malloc");
goto done;
}
sh->sh_h = h;
sh->sh_ys = ys;
sh->sh_default = default_str;
handler->myvoid =(void*)sh;
if ((nh = netsnmp_handler_registration_create(name,
handler,
oid1,
sz1,
modes)) == NULL){
clicon_err(OE_SNMP, errno, "netsnmp_handler_registration_create");
netsnmp_handler_free(handler);
goto done;
}
/*
* XXX: nh->agent_data
*/
if ((ret = netsnmp_register_instance(nh)) < 0){
/* XXX Failures are MIB_REGISTRATION_FAILED and MIB_DUPLICATE_REGISTRATION. */
clicon_err(OE_SNMP, ret, "netsnmp_register_instance");
goto done;
}
clicon_debug(1, "%s %s registered", __FUNCTION__, oidstr);
ok:
retval = 0;
done:
return retval;
}
/*! Check smiv2 extensions for
*
* Called for each node in a mib-yang
* Algorithm is to find smiv2:oid, then its associated parent type (eg leaf, container, list)
* and then register callbacks.
* @param[in] ys Yang node, of type unknown
* @param[in] arg Argument, in effect clicon_handle
* @retval -1 Error
* @retval 0 OK
* @see yang_extension_value
* @see ys_populate_unknown
*/
/*! Traverse mib-yang tree, identify scalars and tables, register OID and callbacks
*
* The tree is traversed depth-first, which at least guarantees that a parent is
* traversed before a child.
* Extensions are grouped in some categories, the one I have seen are, example:
* 1. leaf
* smiv2:max-access "read-write";
* smiv2:oid "1.3.6.1.4.1.8072.2.1.1";
* smiv2:defval "42"; (not always)
* 2. container, list
* smiv2:oid "1.3.6.1.4.1.8072.2.1";
* 3. module level
* smiv2:alias "netSnmpExamples" {
* smiv2:oid "1.3.6.1.4.1.8072.2";
* @param[in] h Clixon handle
* @param[in] yn yang node
* @retval -1 Error, aborted at first error encounter
* @retval 0 OK, all nodes traversed
*/
static int
mib_traverse(clicon_handle h,
yang_stmt *yn)
{
int retval = -1;
yang_stmt *ys = NULL;
yang_stmt *yp;
int ret;
switch(yang_keyword_get(yn)){
case Y_LEAF:
if (mib_yang_leaf(h, yn) < 0)
goto done;
break;
case Y_CONTAINER: // XXX
break;
case Y_LIST: // XXX
yp = yang_parent_get(yn);
if (yang_keyword_get(yp) == Y_CONTAINER){
/* XXX ad-hoc method to find table? now skip */
goto ok;
}
break;
default:
break;
}
ys = NULL;
while ((ys = yn_each(yn, ys)) != NULL) {
if ((ret = mib_traverse(h, ys)) < 0)
goto done;
if (ret > 0){
retval = ret;
goto done;
}
}
ok:
retval = 0;
done:
return retval;
}
int
clixon_snmp_mib_yangs(clicon_handle h)
{
int retval = -1;
char *modname;
cxobj *x;
yang_stmt *yspec;
yang_stmt *ymod;
/* XXX Hardcoded, replace this with generic MIB */
if ((yspec = clicon_dbspec_yang(h)) == NULL){
clicon_err(OE_FATAL, 0, "No DB_SPEC");
goto done;
}
x = NULL;
while ((x = xml_child_each(clicon_conf_xml(h), x, CX_ELMNT)) != NULL) {
if (strcmp(xml_name(x), "CLICON_SNMP_MIB") != 0)
continue;
if ((modname = xml_body(x)) == NULL)
continue;
clicon_debug(1, "%s %s: \"%s\"", __FUNCTION__, xml_name(x), modname);
/* Note, here we assume the Yang is loaded by some other mechanism and
* error if it not found.
* Alternatively, that YANG could be loaded.
* Problem is, if clixon_snmp has not loaded it, has backend done it?
* What happens if backend has not loaded it?
*/
if ((ymod = yang_find(yspec, Y_MODULE, modname)) == NULL){
clicon_err(OE_YANG, 0, "Mib-translated-yang %s not loaded", modname);
goto done;
}
/* Recursively traverse the mib-yang to find extensions */
if (mib_traverse(h, ymod) < 0)
goto done;
}
init_testtable(); // XXX NOTE Must be AFTER loop ^ for unknown reason
retval = 0;
done:
return retval;
}