agent/mibgroup/examples/wombat.c

/*
 *  Template MIB group implementation - wombat.c
 *
 */

#include <config.h>
#include <sys/types.h>

/* mibincl.h contains all the snmp specific headers to define the
   return types and various defines and structures. */
#include "mibincl.h"

#include "wombat.h"


/*  
 *  header_wombat routines are called to implement the final part of
 *  the oid search.  The parent snmpd routines search the subtree
 *  structure, composed of the various entries in the wombat.h file,
 *  to identify the routine likely responsible for the given oid.  vp
 *  points to the subtree element that contained pointers to the
 *  var_wombat routine, and name points to the actual request.  The
 *  var_wombat routine is called with this info, and it calls
 *  header_wombat to either verify that the request is valid (in the
 *  case of a Get [exact == 1]), or turn the request into a valid
 *  request, if possible (in the case of Get Next [exact == 0]).  When
 *  a valid request is found or generated, a pointer to the routine
 *  responsible for handling Set requests is filled in, in case that's
 *  what's really caused our invocation.
 *
 *  The subtree structure only identifies Types.  In the case of Get,
 *  we just check to see if the length is right and the request
 *  matches something we can answer to.  If the oid is a table, we
 *  validate the index.  This routine could be modified to deal with a
 *  single routine handling a sequence or other data structures, but
 *  you're probably reinventing the wheel if you do (the subtree
 *  structure should be used to reduce those cases down to a scalar or
 *  a table).
 *
 *  In the case of Get Next, we have to deal with the fact that the
 *  incoming request is probably not going to match anything --- it
 *  can be too short or too long, or the index of a table might not
 *  match anything actually in the table.
 *
 *  If the incoming request is too short, convert it to the first valid
 *  oid.  If it's too long, match as far as possible, and then convert
 *  it to the next valid oid.  */

	/*********************
	 *
	 *  Kernel & interface information,
	 *   and internal forward declarations
	 *
	 *********************/


void calculate_wombat(void);


	/*********************
	 *
	 *  Initialisation & common implementation functions
	 *
	 *********************/


void init_wombat(void)
{

/* define the structure we're going to ask the agent to register our
   information at */
  struct variable2 wombat_variables[] = {
    { WOMBATUPTIME,  ASN_TIMETICKS, RONLY, var_wombat, 1, {1}},
    { WOMBATCURRENT,   ASN_COUNTER, RONLY, var_wombat, 1, {2}},
    { WOMBATHIGHWATER, ASN_COUNTER, RONLY, var_wombat, 1, {3}}
  };

  /* Define the OID pointer to the top of the mib tree that we're
   registering underneath */
  oid wombat_variables_oid[] = { 1,3,6,1,2,1,99 };

  /* register ourselves with the agent to handle our mib tree */
  REGISTER_MIB("wombat", wobmat_variables, variable2, wombat_variables_oid);

  /* the auto_nlist routine automatically looks up an nlist symbol in
     the kernel and returns the value.  It does not have to be done in
     the init_wombat() routine, but we've put it here for our
     example. */
#ifdef CAN_USE_NLIST
    auto_nlist("wombatstat");
#endif
};

/* function which scans a given snmpd.conf line for information */

void wombat_parse_config(char *word,
			 char *line)
{
}

/* function which frees resources allocated by the .conf parser above
   and resets all values to defaults.  It called just before the agent
   re-reads all the .conf files. */

void wombat_free_config (void) 
{
}


#define MATCH_FAILED	1
#define MATCH_SUCCEEDED	0

/*
  header_wombat(...
  Arguments:
  vp	        IN      - pointer to variable entry that points here
  name          IN/OUT  - IN/name requested, OUT/name found
  length        IN/OUT  - length of IN/OUT oid's 
  exact         IN      - TRUE if an exact match was requested
  var_len       OUT     - length of variable or 0 if function returned
  write_method  OUT     - pointer to function to set variable, otherwise 0
  
*/

int
header_wombat(struct variable *vp,
	      oid *name,
	      int *length,
	      int exact,
	      int *var_len,
	      WriteMethod **write_method)
{
#define WOMBAT_NAME_LENGTH	8
    oid newname[MAX_NAME_LEN];
    int result;
    char c_oid[MAX_NAME_LEN];

    if (snmp_get_do_debugging()) {
      sprint_objid (c_oid, name, *length);
      DEBUGMSGTL(("examples/wombat", "var_wombat: %s %d\n", c_oid, exact));
    }

    memcpy( (char *)newname,(char *)vp->name, (int)vp->namelen * sizeof(oid));
    newname[WOMBAT_NAME_LENGTH] = 0;
    result = snmp_oid_compare(name, *length, newname, (int)vp->namelen + 1);
    if ((exact && (result != 0)) || (!exact && (result >= 0)))
        return(MATCH_FAILED);
    memcpy( (char *)name,(char *)newname, ((int)vp->namelen + 1) * sizeof(oid));
    *length = vp->namelen + 1;

    *write_method = 0;
    *var_len = sizeof(long);	/* default to 'long' results */
    return(MATCH_SUCCEEDED);
}


	/*********************
	 *
	 *  System specific implementation functions
	 *
	 *********************/

u_char	*
var_wombat(struct variable *vp,
	   oid *name,
	   int *length,
	   int exact,
	   int *var_len,
	   WriteMethod **write_method)
{
    if (header_wombat(vp, name, length, exact, var_len, write_method) == MATCH_FAILED )
	return NULL;

    switch (vp->magic){
	case WOMBATUPTIME:
	    long_return = 1;
	    return (u_char *)&long_return;
	default:
	    ERROR_MSG("");
    }
    return NULL;
}


	/*********************
	 *
	 *  Internal implementation functions
	 *
	 *********************/

void calculate_wombat(void)
{
  return;
}