The Net-SNMP library(3)

NAME
The Net-SNMP library -

  Modules
asn1 parsing and datatype manipulation routines.
Note on.

A generic callback mechanism
generic linked-list data handling with a string as a key.
storage space for defaults
The purpose of the default storage is three-fold:.

mib parsing and datatype manipulation routines.
Store and retrieve data referenced by an OID.
This is essentially a way of storing data associated with a given OID.

parsing various configuration files at run time
The read_config related functions are a fairly extensible system of parsing various configuration files at the run time.

generic library based alarm timers for various parts of an application
various PDU processing routines
generic logging for net-snmp
Memory Utility Routines

  Data Structures
struct snmp_internal_session
struct session_list

  Defines
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MIB_CLIENTS_ARE_EVIL 1
#define _init_agent_callback_transport()
#define SNMP_NEED_REQUEST_LIST
#define timercmp(tvp, uvp, cmp)
#define timerclear(tvp) (tvp)->tv_sec = (tvp)->tv_usec = 0
#define MAX_PACKET_LENGTH (0x7fffffff)
#define NETSNMP_STREAM_QUEUE_LEN 5
#define BSD4_2
#define NFDBITS (sizeof(fd_mask) * NBBY)
#define FD_SET(n, p) ((p)->fds_bits[(n)/NFDBITS] |= (1 << ((n) % NFDBITS)))
#define FD_CLR(n, p) ((p)->fds_bits[(n)/NFDBITS] &= ~(1 << ((n) % NFDBITS)))
#define FD_ISSET(n, p) ((p)->fds_bits[(n)/NFDBITS] & (1 << ((n) % NFDBITS)))
#define FD_ZERO(p) memset((p), 0, sizeof(*(p)))
#define DEFAULT_COMMUNITY 'public'
#define DEFAULT_RETRIES 5
#define DEFAULT_TIMEOUT 1000000L
#define DEFAULT_REMPORT SNMP_PORT
#define DEFAULT_ENTERPRISE default_enterprise
#define DEFAULT_TIME 0
#define MAXIMUM_PACKET_SIZE 0x7fffffff
#define DEBUGPRINTPDUTYPE(token, type) DEBUGDUMPSECTION(token, snmp_pdu_type(type))
#define ERROR_STAT_LENGTH 11

  Typedefs
typedef long fd_mask

  Functions
int init_agent (const char *app)
Initialize the agent.
void shutdown_agent (void)
void add_to_init_list (char *module_list)
int should_init (const char *module_name)
int snmp_build (u_char **pkt, size_t *pkt_len, size_t *offset, netsnmp_session *pss, netsnmp_pdu *pdu)
int snmp_get_errno (void)
void snmp_synch_reset (netsnmp_session *notused)
void snmp_synch_setup (netsnmp_session *notused)
const char * strerror (int err)
const char * snmp_pdu_type (int type)
long snmp_get_next_reqid (void)
long snmp_get_next_msgid (void)
long snmp_get_next_sessid (void)
long snmp_get_next_transid (void)
void snmp_perror (const char *prog_string)
void snmp_set_detail (const char *detail_string)
const char * snmp_api_errstring (int snmp_errnumber)
void snmp_error (netsnmp_session *psess, int *p_errno, int *p_snmp_errno, char **p_str)
void snmp_sess_error (void *sessp, int *p_errno, int *p_snmp_errno, char **p_str)
void netsnmp_sess_log_error (int priority, const char *prog_string, netsnmp_session *ss)
void snmp_sess_perror (const char *prog_string, netsnmp_session *ss)
void snmp_sess_init (netsnmp_session *session)
void init_snmp (const char *type)
Calls the functions to do config file loading and mib module parsing in the correct order.
void snmp_store (const char *type)
void snmp_shutdown (const char *type)
Shuts down the application, saving any needed persistent storage, and appropriate clean up.
netsnmp_session * snmp_open (netsnmp_session *session)
netsnmp_session * snmp_open_ex (netsnmp_session *session, int(*fpre_parse)(netsnmp_session *, netsnmp_transport *, void *, int), int(*fparse)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t), int(*fpost_parse)(netsnmp_session *, netsnmp_pdu *, int), int(*fbuild)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t *), int(*frbuild)(netsnmp_session *, netsnmp_pdu *, u_char **, size_t *, size_t *), int(*fcheck)(u_char *, size_t))
int snmpv3_engineID_probe (struct session_list *slp, netsnmp_session *in_session)
probe for peer engineID
netsnmp_session * snmp_add (netsnmp_session *in_session, netsnmp_transport *transport, int(*fpre_parse)(netsnmp_session *, netsnmp_transport *, void *, int), int(*fpost_parse)(netsnmp_session *, netsnmp_pdu *, int))
netsnmp_session * snmp_add_full (netsnmp_session *in_session, netsnmp_transport *transport, int(*fpre_parse)(netsnmp_session *, netsnmp_transport *, void *, int), int(*fparse)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t), int(*fpost_parse)(netsnmp_session *, netsnmp_pdu *, int), int(*fbuild)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t *), int(*frbuild)(netsnmp_session *, netsnmp_pdu *, u_char **, size_t *, size_t *), int(*fcheck)(u_char *, size_t), netsnmp_pdu *(*fcreate_pdu)(netsnmp_transport *, void *, size_t))
void * snmp_sess_add_ex (netsnmp_session *in_session, netsnmp_transport *transport, int(*fpre_parse)(netsnmp_session *, netsnmp_transport *, void *, int), int(*fparse)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t), int(*fpost_parse)(netsnmp_session *, netsnmp_pdu *, int), int(*fbuild)(netsnmp_session *, netsnmp_pdu *, u_char *, size_t *), int(*frbuild)(netsnmp_session *, netsnmp_pdu *, u_char **, size_t *, size_t *), int(*fcheck)(u_char *, size_t), netsnmp_pdu *(*fcreate_pdu)(netsnmp_transport *, void *, size_t))
void * snmp_sess_add (netsnmp_session *in_session, netsnmp_transport *transport, int(*fpre_parse)(netsnmp_session *, netsnmp_transport *, void *, int), int(*fpost_parse)(netsnmp_session *, netsnmp_pdu *, int))
void * snmp_sess_open (netsnmp_session *pss)
int create_user_from_session (netsnmp_session *session)
int snmp_sess_close (void *sessp)
int snmp_close (netsnmp_session *session)
int snmp_close_sessions (void)
int snmpv3_packet_build (netsnmp_session *session, netsnmp_pdu *pdu, u_char *packet, size_t *out_length, u_char *pdu_data, size_t pdu_data_len)
u_char * snmp_pdu_build (netsnmp_pdu *pdu, u_char *cp, size_t *out_length)
int snmpv3_parse (netsnmp_pdu *pdu, u_char *data, size_t *length, u_char **after_header, netsnmp_session *sess)
int snmpv3_make_report (netsnmp_pdu *pdu, int error)
int snmpv3_get_report_type (netsnmp_pdu *pdu)
int snmp_pdu_parse (netsnmp_pdu *pdu, u_char *data, size_t *length)
u_char * snmpv3_scopedPDU_parse (netsnmp_pdu *pdu, u_char *cp, size_t *length)
int snmp_send (netsnmp_session *session, netsnmp_pdu *pdu)
int snmp_sess_send (void *sessp, netsnmp_pdu *pdu)
int snmp_async_send (netsnmp_session *session, netsnmp_pdu *pdu, snmp_callback callback, void *cb_data)
int snmp_sess_async_send (void *sessp, netsnmp_pdu *pdu, snmp_callback callback, void *cb_data)
void snmp_free_var (netsnmp_variable_list *var)
void snmp_free_varbind (netsnmp_variable_list *var)
void snmp_free_pdu (netsnmp_pdu *pdu)
netsnmp_pdu * snmp_create_sess_pdu (netsnmp_transport *transport, void *opaque, size_t olength)
void snmp_read (fd_set *fdset)
int _sess_read (void *sessp, fd_set *fdset)
int snmp_sess_read (void *sessp, fd_set *fdset)
int snmp_select_info (int *numfds, fd_set *fdset, struct timeval *timeout, int *block)
int snmp_sess_select_info (void *sessp, int *numfds, fd_set *fdset, struct timeval *timeout, int *block)
void snmp_timeout (void)
void snmp_sess_timeout (void *sessp)
int snmp_oid_ncompare (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2, size_t max_len)
int snmp_oid_compare (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
lexicographical compare two object identifiers.
int netsnmp_oid_compare_ll (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2, size_t *offpt)
lexicographical compare two object identifiers and return the point where they differ
int snmp_oidtree_compare (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
Compares 2 OIDs to determine if they are equal up until the shortest length.
int snmp_oidsubtree_compare (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
int netsnmp_oid_equals (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
Compares 2 OIDs to determine if they are exactly equal.
int netsnmp_oid_is_subtree (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
Identical to netsnmp_oid_equals, except only the length up to len1 is compared.
int netsnmp_oid_find_prefix (const oid *in_name1, size_t len1, const oid *in_name2, size_t len2)
Given two OIDs, determine the common prefix to them both.
netsnmp_variable_list * snmp_pdu_add_variable (netsnmp_pdu *pdu, const oid *name, size_t name_length, u_char type, const u_char *value, size_t len)
netsnmp_variable_list * snmp_varlist_add_variable (netsnmp_variable_list **varlist, const oid *name, size_t name_length, u_char type, const u_char *value, size_t len)
int snmp_add_var (netsnmp_pdu *pdu, const oid *name, size_t name_length, char type, const char *value)
void * snmp_sess_pointer (netsnmp_session *session)
netsnmp_session * snmp_sess_session (void *sessp)
netsnmp_transport * snmp_sess_transport (void *sessp)
void snmp_sess_transport_set (void *sp, netsnmp_transport *t)
oid * snmp_duplicate_objid (const oid *objToCopy, size_t objToCopyLen)
u_int snmp_increment_statistic (int which)
u_int snmp_increment_statistic_by (int which, int count)
u_int snmp_get_statistic (int which)
void snmp_init_statistics (void)

  Variables
module_init_list * initlist = NULL
module_init_list * noinitlist = NULL
netsnmp_subtree * subtrees
long long_return
u_char return_buf [258]
timeval starttime
int callback_master_num = -1
oid nullOid [] = { 0, 0 }
int nullOidLen = sizeof(nullOid)
session_list * Sessions = NULL
int snmp_errno = 0

Define Documentation

  #define timercmp(tvp, uvp, cmp)

Value:

/* CSTYLED */         ((tvp)->tv_sec cmp (uvp)->tv_sec ||         ((tvp)->tv_sec == (uvp)->tv_sec &&         /* CSTYLED */         (tvp)->tv_usec cmp (uvp)->tv_usec))

Definition at line 148 of file snmp_api.c.

Referenced by netsnmp_addrcache_add(), and snmp_sess_timeout().

Function Documentation

  int _sess_read (void * sessp, fd_set * fdset)

Definition at line 5390 of file snmp_api.c.

References asn_check_packet(), snmp_session::callback, snmp_session::callback_magic, snmp_internal_session::check_packet, netsnmp_transport_s::f_accept, netsnmp_transport_s::f_close, netsnmp_transport_s::f_recv, FD_ISSET, netsnmp_transport_s::flags, snmp_internal_session::hook_build, snmp_internal_session::hook_create_pdu, snmp_internal_session::hook_parse, snmp_internal_session::hook_post, snmp_internal_session::hook_pre, snmp_internal_session::hook_realloc_build, session_list::internal, MAX_PACKET_LENGTH, MAXIMUM_PACKET_SIZE, session_list::next, NULL, snmp_internal_session::packet, snmp_internal_session::packet_len, snmp_internal_session::packet_size, snmp_session::s_errno, snmp_session::s_snmp_errno, session_list::session, Sessions, SNMP_FREE, snmp_log(), snmp_sess_add_ex(), snmp_set_detail(), netsnmp_transport_s::sock, strerror(), and session_list::transport.

Referenced by snmp_sess_read().

  int init_agent (const char * app)

Initialize the agent.

Calls into init_agent_read_config to set tha app's configuration file in the appropriate default storage space, NETSNMP_DS_LIB_APPTYPE. Need to call init_agent before calling init_snmp.

Parameters:
    app the configuration file to be read in, gets stored in default storage

Returns:
    Returns non-zero on failure and zero on success.

See also:
    init_snmp

Definition at line 270 of file snmp_vars.c.

References _init_agent_callback_transport, init_traps(), netsnmp_ds_get_boolean(), netsnmp_ds_set_boolean(), netsnmp_init_helpers(), NULL, setup_tree(), snmp_log(), and starttime.

  void init_snmp (const char * type)

Calls the functions to do config file loading and mib module parsing in the correct order.

Parameters:
    type label for the config file 'type'

Returns:
    void

See also:
    init_agent

Definition at line 766 of file snmp_api.c.

References init_callbacks(), init_snmp_alarm(), init_snmp_logging(), netsnmp_ds_get_string(), netsnmp_ds_set_string(), netsnmp_init_mib(), read_configs(), read_premib_configs(), register_mib_handlers(), and snmp_init_statistics().

  int netsnmp_oid_compare_ll (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2, size_t * offpt)

lexicographical compare two object identifiers and return the point where they differ

Caution: this method is called often by command responder applications (ie, agent).

Returns:
    -1 if name1 < name2, 0 if name1 = name2, 1 if name1 > name2 and offpt = len where name1 != name2

Definition at line 6328 of file snmp_api.c.

Referenced by netsnmp_subtree_change_next(), netsnmp_subtree_change_prev(), and netsnmp_subtree_find_prev().

  int netsnmp_oid_equals (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2)

Compares 2 OIDs to determine if they are exactly equal.

This should be faster than doing a snmp_oid_compare for different length OIDs, since the length is checked first and if != returns immediately. Might be very slighly faster if lengths are ==.

Parameters:
    in_name1 A pointer to the first oid.
    len1 length of the first OID (in segments, not bytes)
    in_name2 A pointer to the second oid.
    len2 length of the second OID (in segments, not bytes)

Returns:
    0 if they are equal, 1 if they are not.

Definition at line 6409 of file snmp_api.c.

Referenced by netsnmp_cache_find_by_oid(), netsnmp_subtree_free(), netsnmp_subtree_load(), netsnmp_unregister_mib_table_row(), and unregister_mib_context().

  int netsnmp_oid_find_prefix (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2)

Given two OIDs, determine the common prefix to them both.

Parameters:
    in_name1 A pointer to the first oid.
    len1 Length of the first oid.
    in_name2 A pointer to the second oid.
    len2 Length of the second oid.

Returns:
    length of largest common index of commonality. 1 = first, 0 if none * or -1 on error.

Definition at line 6465 of file snmp_api.c.

References SNMP_MIN.

Referenced by netsnmp_add_varbind_to_cache().

  int netsnmp_oid_is_subtree (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2)

Identical to netsnmp_oid_equals, except only the length up to len1 is compared.

Functionally, this determines if in_name2 is equal or a subtree of in_name1

Parameters:
    in_name1 A pointer to the first oid.
    len1 length of the first OID (in segments, not bytes)
    in_name2 A pointer to the second oid.
    len2 length of the second OID (in segments, not bytes)

Returns:
    0 if one is a common prefix of the other.

Definition at line 6445 of file snmp_api.c.

  int snmp_oid_compare (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2)

lexicographical compare two object identifiers.

Caution: this method is called often by command responder applications (ie, agent).

Returns:
    -1 if name1 < name2, 0 if name1 = name2, 1 if name1 > name2

Definition at line 6279 of file snmp_api.c.

Referenced by check_getnext_results(), convert_v2pdu_to_v1(), find_varbind_in_list(), lookup_cache_find(), netsnmp_bulk_to_next_fix_requests(), netsnmp_check_getnext_reply(), netsnmp_container_table_row_insert(), netsnmp_insert_iterator_context(), netsnmp_insert_table_row(), netsnmp_instance_helper_handler(), netsnmp_iterator_row_get_byoid(), netsnmp_iterator_row_next_byoid(), netsnmp_scalar_group_helper_handler(), netsnmp_scalar_helper_handler(), netsnmp_send_traps(), netsnmp_stash_to_next_helper(), netsnmp_subtree_compare(), netsnmp_subtree_find(), netsnmp_subtree_find_next(), netsnmp_subtree_find_prev(), netsnmp_subtree_load(), netsnmp_subtree_split(), netsnmp_table_data_add_row(), netsnmp_table_data_get_from_oid(), netsnmp_table_data_helper_handler(), netsnmp_table_data_row_next_byoid(), netsnmp_tdata_compare_oid(), netsnmp_watched_spinlock_handler(), netsnmp_watched_timestamp_handler(), netsnmp_watcher_helper_handler(), snmp_oidsubtree_compare(), snmp_oidtree_compare(), and table_helper_handler().

  int snmp_oidtree_compare (const oid * in_name1, size_t len1, const oid * in_name2, size_t len2)

Compares 2 OIDs to determine if they are equal up until the shortest length.

Parameters:
    in_name1 A pointer to the first oid.
    len1 length of the first OID (in segments, not bytes)
    in_name2 A pointer to the second oid.
    len2 length of the second OID (in segments, not bytes)

Returns:
    0 if they are equal, 1 if in_name1 is > in_name2, or -1 if <.

Definition at line 6381 of file snmp_api.c.

References snmp_oid_compare().

Referenced by netsnmp_query_walk(), and netsnmp_tdata_compare_subtree_oid().

  void snmp_shutdown (const char * type)

Shuts down the application, saving any needed persistent storage, and appropriate clean up.

Parameters:
    type Label for the config file 'type' used

Returns:
    void

Definition at line 834 of file snmp_api.c.

References clear_callback(), netsnmp_ds_shutdown(), NULL, shutdown_mib(), shutdown_snmp_logging(), snmp_alarm_unregister_all(), snmp_call_callbacks(), snmp_close_sessions(), snmp_store(), and unregister_all_config_handlers().

  int snmpv3_engineID_probe (struct session_list * slp, netsnmp_session * in_session)

probe for peer engineID

Parameters:
    slp session list pointer.
    in_session session for errors

Note:

    •   called by _sess_open(), snmp_sess_add_ex()

    •   in_session is the user supplied session provided to those functions.

    •   the first session in slp should the internal allocated copy of in_session

Returns:
    0 : error

    1 : ok

Definition at line 1254 of file snmp_api.c.

References create_user_from_session(), snmp_session::engineBoots, snmp_session::engineTime, snmp_session::flags, NULL, snmp_session::s_snmp_errno, snmp_session::securityEngineID, snmp_session::securityEngineIDLen, session_list::session, snmp_api_errstring(), snmp_errstring(), snmp_sess_synch_response(), TRUE, and snmp_session::version.

Referenced by snmp_sess_add_ex().