snmp_agent.c

嵌入式操作系统ECOS的网络开发包

//==========================================================================
//
//      ./agent/current/src/snmp_agent.c
//
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//####UCDSNMPCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from the UCD-SNMP
// project,  <http://ucd-snmp.ucdavis.edu/>  from the University of
// California at Davis, which was originally based on the Carnegie Mellon
// University SNMP implementation.  Portions of this software are therefore
// covered by the appropriate copyright disclaimers included herein.
//
// The release used was version 4.1.2 of May 2000.  "ucd-snmp-4.1.2"
// -------------------------------------------
//
//####UCDSNMPCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    hmt
// Contributors: hmt
// Date:         2000-05-30
// Purpose:      Port of UCD-SNMP distribution to eCos.
// Description:  
//              
//
//####DESCRIPTIONEND####
//
//==========================================================================
/********************************************************************
       Copyright 1989, 1991, 1992 by Carnegie Mellon University

			  Derivative Work -
Copyright 1996, 1998, 1999, 2000 The Regents of the University of California

			 All Rights Reserved

Permission to use, copy, modify and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appears in all copies and
that both that copyright notice and this permission notice appear in
supporting documentation, and that the name of CMU and The Regents of
the University of California not be used in advertising or publicity
pertaining to distribution of the software without specific written
permission.

CMU AND THE REGENTS OF THE UNIVERSITY OF CALIFORNIA DISCLAIM ALL
WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL CMU OR
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA BE LIABLE FOR ANY SPECIAL,
INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
FROM THE LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*********************************************************************/
/*
 * snmp_agent.c
 *
 * Simple Network Management Protocol (RFC 1067).
 */
/***********************************************************
	Copyright 1988, 1989 by Carnegie Mellon University

                      All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of CMU not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

CMU DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
CMU BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.
******************************************************************/

#include <config.h>

#include <sys/types.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
#  include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#if HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#include <errno.h>
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif

#if HAVE_DMALLOC_H
#include <dmalloc.h>
#endif

#include "asn1.h"
#define SNMP_NEED_REQUEST_LIST
#include "snmp_api.h"
#include "snmp_impl.h"
#include "snmp.h"
#include "mib.h"
#include "snmp_client.h"

#include "snmp_vars.h"
#include "snmpd.h"
#include "mibgroup/struct.h"
#include "mibgroup/util_funcs.h"
#include "var_struct.h"
#include "read_config.h"
#include "snmp_logging.h"
#include "snmp_debug.h"
#include "mib_module_config.h"

#include "default_store.h"
#include "ds_agent.h"
#include "snmp_agent.h"
#include "agent_trap.h"

static int snmp_vars_inc;

static struct agent_snmp_session *agent_session_list = NULL;


static void dump_var(oid *, size_t, int, void *, size_t);
static int goodValue(u_char, size_t, u_char, size_t);
static void setVariable(u_char *, u_char, size_t, u_char *, size_t);

static void dump_var (
    oid *var_name,
    size_t var_name_len,
    int statType,
    void *statP,
    size_t statLen)
{
    char buf [SPRINT_MAX_LEN];
    struct variable_list temp_var;

    temp_var.type = statType;
    temp_var.val.string = (u_char *)statP;
    temp_var.val_len = statLen;
    sprint_variable (buf, var_name, var_name_len, &temp_var);
    snmp_log(LOG_INFO, "    >> %s\n", buf);
}


int getNextSessID()
{
    static int SessionID = 0;

    return ++SessionID;
}

int
agent_check_and_process(int block) {
  int numfds;
  fd_set fdset;
  struct timeval	timeout, *tvp = &timeout;
  int count;
  int fakeblock=0;
  
  tvp =  &timeout;
  tvp->tv_sec  = 0;
  tvp->tv_usec = 0;

  numfds = 0;
  FD_ZERO(&fdset);
  snmp_select_info(&numfds, &fdset, tvp, &fakeblock);
  if (block == 1 && fakeblock == 1)
    tvp = NULL; /* block without timeout */
  else if (block == 0) {
      tvp->tv_sec = 0;
      tvp->tv_usec = 0;
  }

  count = select(numfds, &fdset, 0, 0, tvp);

  if (count > 0){
    /* packets found, process them */
    snmp_read(&fdset);
  } else switch(count){
    case 0:
      snmp_timeout();
      break;
    case -1:
      if (errno == EINTR){
        return -1;
      } else {
        snmp_log_perror("select");
      }
      return -1;
    default:
      snmp_log(LOG_ERR, "select returned %d\n", count);
      return -1;
  }  /* endif -- count>0 */
  return count;
}


/*
 * The session is created using the "traditional API" routine snmp_open()
 * so is linked into the global library Sessions list.  It also opens a
 * socket that listens for incoming requests.
 * 
 *   The agent runs in an infinite loop (in the 'receive()' routine),
 * which calls snmp_read() when such a request is received on this socket.
 * This routine then traverses the library 'Sessions' list to identify the
 * relevant session and eventually invokes '_sess_read'.
 *   This then processes the incoming packet, calling the pre_parse, parse,
 * post_parse and callback routines in turn.
 */

	/* Global access to the primary session structure for this agent.
		for Index Allocation use initially. */
struct snmp_session *main_session;

int
init_master_agent(int dest_port, 
                  int (*pre_parse) (struct snmp_session *, snmp_ipaddr),
                  int (*post_parse) (struct snmp_session *, struct snmp_pdu *,int))
{
    struct snmp_session sess, *session;

    if ( ds_get_boolean(DS_APPLICATION_ID, DS_AGENT_ROLE) != MASTER_AGENT )
	return 0; /* no error if ! MASTER_AGENT */

    DEBUGMSGTL(("snmpd","installing master agent on port %d\n", dest_port));

    snmp_sess_init( &sess );
    
    sess.version = SNMP_DEFAULT_VERSION;
    sess.peername = SNMP_DEFAULT_PEERNAME;
    sess.community_len = SNMP_DEFAULT_COMMUNITY_LEN;
     
    sess.local_port = dest_port;
    sess.callback = handle_snmp_packet;
    sess.authenticator = NULL;
    sess.flags = ds_get_int(DS_APPLICATION_ID, DS_AGENT_FLAGS);
    session = snmp_open_ex( &sess, pre_parse, 0, post_parse, 0, 0 );

    if ( session == NULL ) {
      /* diagnose snmp_open errors with the input struct snmp_session pointer */
	snmp_sess_perror("init_master_agent", &sess);
		return 1;
    }
    main_session = session;
	return 0;
}

struct agent_snmp_session  *
init_agent_snmp_session( struct snmp_session *session, struct snmp_pdu *pdu )
{
    struct agent_snmp_session  *asp;

    asp = malloc( sizeof( struct agent_snmp_session ));
    if ( asp == NULL )
	return NULL;
    asp->start = pdu->variables;
    asp->end   = pdu->variables;
    if ( asp->end != NULL )
	while ( asp->end->next_variable != NULL )
	    asp->end = asp->end->next_variable;
    asp->session = session;
    asp->pdu     = pdu;
    asp->rw      = READ;
    asp->exact   = TRUE;
    asp->outstanding_requests = NULL;
    asp->next    = NULL;
    asp->mode    = RESERVE1;
    asp->status  = SNMP_ERR_NOERROR;

    return asp;
}

int
count_varbinds( struct snmp_pdu *pdu )
{
  int count = 0;
  struct variable_list *var_ptr;
  
  for ( var_ptr = pdu->variables ; var_ptr != NULL ;
		  	var_ptr = var_ptr->next_variable )
	count++;

  return count;
}

int
handle_snmp_packet(int operation, struct snmp_session *session, int reqid,
                   struct snmp_pdu *pdu, void *magic)
{
    struct agent_snmp_session  *asp;
    int status, allDone, i;
    struct variable_list *var_ptr, *var_ptr2;

    if ( magic == NULL ) {
	asp = init_agent_snmp_session( session, snmp_clone_pdu(pdu) );
	status = SNMP_ERR_NOERROR;
    }
    else {
	asp = (struct agent_snmp_session *)magic;
        status =   asp->status;
    }

    if (asp->outstanding_requests != NULL)
	return 1;

    if ( check_access(pdu) != 0) {
        /* access control setup is incorrect */
	send_easy_trap(SNMP_TRAP_AUTHFAIL, 0);
        if (asp->pdu->version != SNMP_VERSION_1 && asp->pdu->version != SNMP_VERSION_2c) {
            asp->pdu->errstat = SNMP_ERR_AUTHORIZATIONERROR;
            asp->pdu->command = SNMP_MSG_RESPONSE;
            snmp_increment_statistic(STAT_SNMPOUTPKTS);
            snmp_send( asp->session, asp->pdu );
            free( asp );
            return 1;
        } else {
            /* drop the request */
            free( asp );
            return 0;
        }
    }

    switch (pdu->command) {
    case SNMP_MSG_GET:
	if ( asp->mode != RESERVE1 )
	    break;			/* Single pass */
        snmp_increment_statistic(STAT_SNMPINGETREQUESTS);
	status = handle_next_pass( asp );
	asp->mode = RESERVE2;
	break;

    case SNMP_MSG_GETNEXT:
	if ( asp->mode != RESERVE1 )
	    break;			/* Single pass */
        snmp_increment_statistic(STAT_SNMPINGETNEXTS);
	asp->exact   = FALSE;
	status = handle_next_pass( asp );
	asp->mode = RESERVE2;
	break;

    case SNMP_MSG_GETBULK:
	    /*
	     * GETBULKS require multiple passes. The first pass handles the
	     * explicitly requested varbinds, and subsequent passes append
	     * to the existing var_op_list.  Each pass (after the first)
	     * uses the results of the preceeding pass as the input list
	     * (delimited by the start & end pointers.
	     * Processing is terminated if all entries in a pass are
	     * EndOfMib, or the maximum number of repetitions are made.
	     */
	if ( asp->mode == RESERVE1 ) {
            snmp_increment_statistic(STAT_SNMPINGETREQUESTS);
	    asp->exact   = FALSE;
		    /*
		     * Limit max repetitions to something reasonable
		     *	XXX: We should figure out what will fit somehow...
		     */
	    if ( asp->pdu->errindex > 100 )
	        asp->pdu->errindex = 100;
    
	    status = handle_next_pass( asp );	/* First pass */
	    asp->mode = RESERVE2;
	    if ( status != SNMP_ERR_NOERROR )
	        break;
    
	    while ( asp->pdu->errstat-- > 0 )	/* Skip non-repeaters */
	        asp->start = asp->start->next_variable;
	    asp->pdu->errindex--;           /* Handled first repetition */

	    if ( asp->outstanding_requests != NULL )
		return 1;
	}

	while ( asp->pdu->errindex-- > 0 ) {	/* Process repeaters */
		/*
		 * Add new variable structures for the
		 * repeating elements, ready for the next pass.
		 * Also check that these are not all EndOfMib
		 */