On Wed, 2008-08-27 at 14:14 +0200, Hanig, Michael wrote: > Hello there, > > I stumbled upon some problems using net-snmp for creating a sub-agent. > I was able to figure out most of the stuff, but there are still some > questions left. > > I) What is the difference between > > netsnmp_register_watched_scalar() > > and > > netsnmp_register_watched_instance() > > ?
Assume that you are calling the registration code with <theOid> as the OID, then _instance registers a variable at <theOid> while _scalar registers a variable at <theOid>.0, this is useful for simple scalar variables that are declared outside of any table in the MIB. > Besides *_instance mostly seems to work as I want it to and *_scalar > doesn’t. ;) Sounds like _the_ argument for using _instance. > II) Why does net-snmp behave different with the following code: > > 1) netsnmp_register_watched_instance( > netsnmp_create_handler_registration( > “one”, > NULL, > my_oid1, > OID_LENGTH(my_oid1), > HANDLER_CAN_RWRITE), > netsnmp_create_watcher_info( > (void *)&string, > sizeof(string), > ASN_OCTET_STR, > WATCHER_MAX_SIZE)); > > snmpget/-set works fine > > 2) netsnmp_register_watched_instance( > netsnmp_create_handler_registration( > “two”, > NULL, > my_oid2, > OID_LENGTH(my_oid2), > HANDLER_CAN_RWRITE), > netsnmp_create_watcher_info( > (void *)&integer, > sizeof(integer), > ASN_INTEGER, > WATCHER_FIXED_SIZE)); > > snmpget works fine / snmpset doesn’t work (wrong type or length) What exact commad are you issuing? > 3) netsnmp_register_int_instance( > “two”, > my_oid2, > OID_LENGTH(my_oid2), > &integer, > NULL); > > snmpget/-set works fine In 5.5 (trunk) this is equivalent to 2) and the _watched code is rewritten. In all previous versions this calls a different handling routine. Could you pleease check if your problem is present in the trunk version as well? f there is a bug I would rather know about it now than later. > Is it safe to use the netsnmp_register_int_instance rather than the > netsnmp_register_watched_instance? They should be functionally equivalent. > III) How do I correctly add an OID in a table? > > I tried > > netsnmp_set_row_column(netsnmp_row, 2, ASN_OBJECT_ID, “\0”, > sizeof(“\0”)); /* OID 0.0 */ > > which should be fine to my understanding of OID-encoding. But the > agent refuses to generate a paket because of a bad sub-identifier, so > the request times out. I also tried to add a more complex OID (i.e. > 2.100.3) accordingly to the above example with “\x81\x34\x03” but I > may be totally wrong with that. > > Perhaps I only need a point to the right direction. I failed to understand question III /MF ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Net-snmp-coders mailing list Net-snmp-coders@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/net-snmp-coders
