Net-SNMP SNMP_API(3)
NAME
snmp_sess_init, snmp_open, snmp_send, snmp_free_pdu,
snmp_select_info, snmp_read, snmp_timeout, snmp_close,
snmp_perror, snmp_sess_perror, snmp_error,
snmp_api_errstring - send and receive SNMP messages
SYNOPSIS
#include
void snmp_sess_init ( struct snmp_session * );
struct snmp_session * snmp_open ( struct snmp_session *);
/* Input parameter not used inint snmp_send ( struct snmp_session *session,
struct snmp_pdu *pdu );
int snmp_select_info ( int *numfds, fd_set *fdset,
struct timeval *timeout, int *block );void snmp_read ( fd_set *fdset );
void snmp_timeout ( void );
int snmp_close ( struct snmp_session *session );
void snmp_free_pdu ( struct snmp_pdu *pdu );
void snmp_error ( struct snmp_session *session,
int *pcliberr, int *psnmperr, char **pperrstring );char *snmp_api_errstring ( int snmperr );
void snmp_perror ( char * msg );
/* for parsing errors only */void snmp_sess_perror (char * msg, struct snmp_session *);
/* all other SNMP library errorsDESCRIPTION
Snmp_sess_init prepares a struct snmp_session that sources
transport characteristics and common information that willbe used for a set of SNMP transactions. After this struc-
ture is passed to snmp_open to create an SNMP session, the
structure is not used.Snmp_open returns a pointer to a newly-formed struct
snmp_session object, which the application must use to
reference the active SNMP session.Snmp_send and snmp_free_pdu each take as input a pointer to
a struct snmp_pdu object. This structure contains
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information that describes a transaction that will be per-
formed over an open session.Consult snmp_api.h for the definitions of these structures.
Snmp_read, snmp_select_info, and snmp_timeout provide an
interface for the use of the select(2) system call so that SNMP transactions can occur asynchronously.Snmp_select_info is given the information that would have
been passed to select in the absence of SNMP. For example,this might include window update information. This informa-
tion is modified so that SNMP will get the service it requires from the call to select. In this case, numfds, fdset, and timeout correspond to the nfds, readfds, andtimeout arguments to select, respectively. The only excep-
tion is that timeout must always point to an allocated (but perhaps uninitialized) struct timeval. If timeout would have been passed as NULL, block is set to true, and timeout is treated as undefined. This same rule applies upon returnfrom snmp_select_info.
After calling snmp_select_info, select is called with the
returned data. When select returns, snmp_read should be
called with the fd_set returned from select to read each
SNMP socket that has input. If select times out,snmp_timeout should be called to see if the timeout was
intended for SNMP. DIAGNOSTICSPrevious versions of the library used snmp_get_errno to read
the global variable snmp_errno which may have held the error
status within the SNMP library. The existing methodsnmp_perror should be used to log ASN.1 coding errors only.
The new method snmp_sess_perror is provided to capture
errors that occur during the processing of a particular SNMPsession. Snmp_sess_perror calls snmp_error function to
obtain the "C" library error errno , the SNMP library error snmperr , and the SNMP library detailed error message that is associated with an error that occurred during a given session.Note that in all cases except one, snmp_sess_perror should
be handed the struct snmp_session * pointer returned from
snmp_open. If snmp_open returns a null pointer, pass the
INPUT struct snmp_session * pointer used to call snmp_open.
Error return status from snmp_close and snmp_send is indi-
cated by return of 0. A successful status will return a 1for snmp_close and the request id of the packet for
snmp_send. Upon successful return from snmp_send the pdu
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will be freed by the library.Consult snmp_api.h for the complete set of SNMP library
error values. The SNMP library error value snmperr can be one of the following values:SNMPERR_GENERR A generic error occurred.
SNMPERR_BAD_LOCPORT The local port was bad because it
had already been allocated or permission was denied.SNMPERR_BAD_ADDRESS The host name or address given
was not useable.SNMPERR_BAD_SESSION The specified session was not
open.SNMPERR_TOO_LONG
SNMPERR_NO_SOCKET
SNMPERR_V2_IN_V1
SNMPERR_V1_IN_V2
SNMPERR_BAD_REPEATERS
SNMPERR_BAD_REPETITIONS
SNMPERR_BAD_ASN1_BUILD
SNMPERR_BAD_SENDTO
SNMPERR_BAD_PARSE
SNMPERR_BAD_VERSION
SNMPERR_NOAUTH_DESPRIV
SNMPERR_ABORT
SNMPERR_UNKNOWN_PDU
SNMPERR_TIMEOUT
A string representation of the error code can be obtainedwith snmp_api_errstring, and a standard error message may be
printed using snmp_perror that functions like the perror
standard routine. V5.4.1 Last change: 21 Oct 1999 3Net-SNMP SNMP_API(3)
SEE ALSO
select(2), snmp_api.h
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:box; cbp-1 | cbp-1 l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE =
Availability system/management/snmp/net-snmp = Interface
Stability Volatile NOTESSource for net-snmp is available on http://opensolaris.org.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:_______________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|____________________|__________________________________|_
| Availability | system/management/snmp/net-snmp|
|____________________|__________________________________|_
| Interface Stability| Volatile ||____________________|_________________________________|
NOTESSource for net-snmp is available on http://opensolaris.org.
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