snmp 학습 노트 의 3－netsnmp Agent 개발

snmp 학습 노트 의 3－netsnmp Agent 개발
November 27th, 2008
BianJiang
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By: Bian Jiang ([email protected])

From: http://www.b0rder.com

Date: 2008.11.11

1.mib 라 이브 러 리 파일 BVCOM-SYSTEMUPTIME-MIB.txt:

BVCOM-SYSTEMUPTIME-MIB DEFINITIONS ::= BEGIN

IMPORTS
    TimeTicks   FROM SNMPv2-SMI
    enterprises      FROM SNMPv2-SMI
    OBJECT-TYPE, Integer32, MODULE-IDENTITY      FROM SNMPv2-SMI;

bvcom    OBJECT IDENTIFIER ::= { enterprises 26814 }

ipq6800    OBJECT IDENTIFIER ::= { bvcom 6800 }

bvcomAgentModules   OBJECT IDENTIFIER ::= { ipq6800 1 }

bvcomAgentModuleObject OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
    "This is an object that simply supports a writable integer
     when compiled into the agent.  See
     http://www.net-snmp.org/tutorial-5/toolkit/XXX for further
     implementation details."
    DEFVAL { 1 }
    ::= { bvcomAgentModules 1 }

bvcomAgentSubagentObject OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
    "This is an object that simply supports a writable integer
     when attached to the agent.  The object should be accessible
     when the agentx subagent containing this object is attached.
     See http://www.net-snmp.org/tutorial-5/toolkit/XXX for
     further implementation details."
    DEFVAL { 2 }
    ::= { bvcomAgentModules 2 }

bvcomAgentPluginObject OBJECT-TYPE
    SYNTAX      Integer32
    MAX-ACCESS  read-write
    STATUS      current
    DESCRIPTION
    "This is an object that simply supports a writable integer
     when attached to the agent.  This object should be accessible
     when the dynamic plugin has been loaded into the agent.  See
     http://www.net-snmp.org/tutorial-5/toolkit/XXX for further
     implementation details."
    DEFVAL { 3 }
    ::= { bvcomAgentModules 3 }

END

PS:      mib    /etc/profile     SNMPCONFPATH    

   
   
   
   


    
    
    
    

      export SNMPCONFPATH=/usr/local/share/snmp/ 
    

    
    
    
    

      export MIBS=ALL 
    
   
   
   
   

2.mib 라 이브 러 리 파일 을/usr/local/share/snmp/mibs/로 복사 합 니 다.

sudo cp BVCOM-SYSTEMUPTIME-MIB.txt /usr/local/share/snmp/mibs/

3.mib 라 이브 러 리 불 러 오기:

cat /usr/local/share/snmp/snmp.conf
mibs +BVCOM-SYSTEMUPTIME-MIB

4.mib 가 정상적으로 불 러 오 는 지 확인 하기:

border@debian:/work/border/snmp/example-demon$ snmptranslate -IR -Tp bvcom
+--bvcom(26814)
   |
   +--ipq6800(6800)
      |
      +--bvcomAgentModules(1)
         |
         +-- -RW- Integer32 bvcomAgentModuleObject(1)
         +-- -RW- Integer32 bvcomAgentSubagentObject(2)
         +-- -RW- Integer32 bvcomAgentPluginObject(3)

5.mib2c 가 지원 하 는 템 플 릿 보기:

border@debian:/work/border/snmp/example-demon$ ls /usr/local/share/snmp/
mib2c.access_functions.conf    mib2c.create-dataset.conf  mib2c.scalar.conf
mib2c.array-user.conf          mib2c-data                 mib2c.table_data.conf
mib2c.check_values.conf        mib2c.genhtml.conf         mibs
mib2c.check_values_local.conf  mib2c.int_watch.conf       snmp.conf
mib2c.column_defines.conf      mib2c.iterate_access.conf  snmp.conf~
mib2c.column_enums.conf        mib2c.iterate.conf         snmpconf-data
mib2c.column_storage.conf      mib2c.mfd.conf             snmpd.conf
mib2c.conf                     mib2c.notify.conf          snmp_perl.pl
mib2c.container.conf           mib2c.old-api.conf         snmp_perl_trapd.pl

6.템 플 릿 을 통 해.c 와.h 파일 생 성:

border@debian:/work/border/snmp/example-demon$ mib2c -c mib2c.int_watch.conf bvcomAgentModules
writing to -
*** Warning: only generating code for nodes of MIB type INTEGER
writing to bvcomAgentModules.h
writing to bvcomAgentModules.c
running indent on bvcomAgentModules.c
running indent on bvcomAgentModules.h

7.snmp 를 통 해agent_api 수호 프로그램 example-demon.c 작성:

#include <net-snmp/net-snmp-config.h>
#include <net-snmp/net-snmp-includes.h>
#include <net-snmp/agent/net-snmp-agent-includes.h>
#include <signal.h>
#include "bvcomAgentModules.h"

static int keep_running;

RETSIGTYPE
stop_server(int a) {
    keep_running = 0;
}

int
main (int argc, char **argv) {

    int agentx_subagent=0; /* change this if you want to be a SNMP master agent */
    int background = 0; /* change this if you want to run in the background */
    int syslog = 0; /* change this if you want to use syslog */

    /* print log errors to syslog or stderr */

    if (syslog)
        snmp_enable_calllog();
    else
        snmp_enable_stderrlog();

    /* we're an agentx subagent? */
    if (agentx_subagent) {
        /* make us a agentx client. */
        netsnmp_ds_set_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_ROLE, 1);
    }

    /* run in background, if requested */
    if (background && netsnmp_daemonize(1, !syslog))
        exit(1);

    /* Initialize tcpip, if necessary */
    SOCK_STARTUP;

    /* Initialize the agent library */
    init_agent("example-demon"); //      

    /* Initialize our mib code here */
    printf("Before init bvcomAgentModules 
");

    init_bvcomAgentModules(); //       

    printf("End init bvcomAgentModules 
");

    /* initialize vacm/usm access control  */
    if (!agentx_subagent) {
        void  init_vacm_vars();
        void  init_usmUser();
    }

    /* Example-demon will be used to read example-demon.conf files. */
    init_snmp("example-demon");

    /* If we're going to be a snmp master agent, initial the ports */
    if (!agentx_subagent)
        init_master_agent();  /* open the port to listen on (defaults to udp:161) */

    printf("---------------------
");
    /* In case we recevie a request to stop (kill -TERM or kill -INT) */
    keep_running = 1;
    signal(SIGTERM, stop_server);

    signal(SIGINT, stop_server);

    snmp_log(LOG_INFO,"example-demon is up and running.
");

    /* your main loop here... */
    while(keep_running) {
        /* if you use select(), see snmp_select_info() in snmp_api(3) */
        /*     --- OR ---  */
        agent_check_and_process(1); /* 0 == don't block */

    }

    /* at shutdown time */
    snmp_shutdown("example-demon");
    SOCK_CLEANUP;
    return 0;
}

8.Makefile:

CC=gcc

OBJS2=example-demon.o bvcomAgentModules.o
TARGETS=example-demon

CFLAGS=-I. `net-snmp-config --cflags`
BUILDLIBS=`net-snmp-config --libs`
BUILDAGENTLIBS=`net-snmp-config --agent-libs`

# shared library flags (assumes gcc)
DLFLAGS=-fPIC -shared

all: $(TARGETS)

example-demon: $(OBJS2)
    $(CC) -o example-demon $(OBJS2)  $(BUILDAGENTLIBS)

clean:
    rm $(OBJS2) $(OBJS2) $(TARGETS)

9.example-demon.conf:

###############################################################################
# Access Control
###############################################################################

#       sec.name  source          community
com2sec local     localhost       public
com2sec mynetwork 192.168.0.0/24      public

####
# Second, map the security names into group names:

#                 sec.model  sec.name
group MyRWGroup    v1         local
group MyRWGroup    v2c        local
group MyRWGroup    usm        local
group MyROGroup v1         mynetwork
group MyROGroup v2c        mynetwork
group MyROGroup usm        mynetwork

####
# Third, create a view for us to let the groups have rights to:

#           incl/excl subtree                          mask
view all    included  .1                               80

####
# Finally, grant the 2 groups access to the 1 view with different
# write permissions:

#              context sec.model sec.level match  read   write  notif
access MyROGroup ""      any       noauth    exact  all    none   none
access MyRWGroup ""      any       noauth    exact  all    all    none

agentaddress 161

10.example-demon 을 실행 할 때 슈퍼 관리자 로 실행 해 야 합 니 다.그렇지 않 으 면 오류 가 발생 할 수 있 습 니 다.

sudo ./example-demon

a.슈퍼 관리 자 를 사용 하지 않 았 을 때 보 고 된 오류:

border@debian:/work/border/snmp/example-demon$ ./example-demon
netsnmp_assert !"registration != duplicate" failed agent_registry.c:535 netsnmp_subtree_load()
netsnmp_assert !"registration != duplicate" failed agent_registry.c:535 netsnmp_subtree_load()
netsnmp_assert !"registration != duplicate" failed agent_registry.c:535 netsnmp_subtree_load()
Before init bvcomAgentModules
End init bvcomAgentModules
Error opening specified endpoint "161"
---------------------
example-demon is up and running.
read_config_store open failure on /var/net-snmp/example-demon.conf
read_config_store open failure on /var/net-snmp/example-demon.conf
read_config_store open failure on /var/net-snmp/example-demon.conf

b.지 정 된 endpoint""오 류 를 보고 하면 example-demon.conf 설정 파일 에 에이전트 address 161 이 없다 는 것 을 설명 합 니 다.
11.설정 파일 을~/.snmp/디 렉 터 리 로 복사 합 니 다.

cp example-demon.conf /home/border/.snmp/

12.sudo ./example-demon:

border@debian:~$ snmpwalk -v1 -c public localhost bvcom
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentModuleObject.0 = INTEGER: 68001
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentSubagentObject.0 = INTEGER: 68002
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentPluginObject.0 = INTEGER: 68003
End of MIB

인증:

border@debian:~$ snmpget -v1 -c public localhost bvcomAgentModuleObject.0
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentModuleObject.0 = INTEGER: 68001

border@debian:~$ snmpgetnext -v1 -c public localhost bvcomAgentModuleObject.0
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentSubagentObject.0 = INTEGER: 68002

13.snmpv 3 지원 설정 파일 에 추가:

rwuser border
rwuser border1
createUser border MD5 "bvcombjbj" DES
createUser border1 SHA "bvcombjbj" AES
(          ：createUser border1 SHA "bvcombjbj" AES128)

다음 명령 검증 을 통 해:
a.MD5 검증:

snmpwalk -v3 -l authPriv -u border -A bvcombjbj -X bvcombjbj localhost bvcom
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentModuleObject.0 = INTEGER: 68001
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentSubagentObject.0 = INTEGER: 68002
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentPluginObject.0 = INTEGER: 68003

b.검증 SHA:

snmpwalk -v3 -l authPriv -u border1 -a SHA -x AES -A bvcombjbj -X bvcombjbj localhost bvcom
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentModuleObject.0 = INTEGER: 68001
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentSubagentObject.0 = INTEGER: 68002
BVCOM-SYSTEMUPTIME-MIB::bvcomAgentPluginObject.0 = INTEGER: 68003

AES 128 을 사용한다 면-x AES 를-x AES 128 로 바 꿔 야 합 니 다.

snmpwalk -v3 -l authPriv -u border1 -a SHA -x AES128 -A bvcombjbj -X bvcombjbj localhost bvcom

참고:
NET-SNMP 패키지 개발 단순 클 라 이언 트 에이전트http://b0rder.com/wiki/NetSnmp/NetSnmpSimpleAgentMib
snmpd.examples 설정 정보 관련http://www.net-snmp.org/docs/man/snmpd.examples.html

snmp_agent_api http://www.net-snmp.org/docs/man/snmp_agent_api.html

Tutorial http://www.nwsmith.net/HintsTips/net-snmp-tutorial.htm

http://www.net-snmp.org/wiki/index.php/TUT:SNMPv3_Options

By: Bian Jiang ([email protected])

From: http://www.b0rder.com

Date: 2008.11.11

–EOF–