net-snmp扩展trap类型的私有mib
注：本文介绍的是静态编译的方法扩展的私有mib，别的方法请看本人整理的《 net-snmp agent开发（用net-snmp扩展MIB库） 》
1. 首先创建一个简单的含有table变量的mib文件取名test-trap.mib，后缀名也可以是.txt 实际操作没有区别；
TEST-TRAP-MIB DEFINITIONS ::= BEGINIMPORTSMODULE-IDENTITY, OBJECT-TYPE, TimeTicks FROM SNMPv2-SMIDisplayString, FROM SNMPv2-TCenterprisesFROM RFC1155-SMI;test OBJECT IDENTIFIER ::= { enterprises 1000 }TestTraps OBJECT IDENTIFIER ::= { test 1 }cpuRatioHigh NOTIFICATION-TYPEOBJECTS {SystemTrapDescription}STATUS currentDESCRIPTION"."::= { TestTraps 1 } TestDescription OBJECT IDENTIFIER ::= { TestTraps 2 }TestTrapDescription OBJECT-TYPESYNTAX DisplayString (SIZE (0..256))MAX-ACCESS read-onlySTATUS currentDESCRIPTION " "::= { TestDescription 1 }END
2. 将创建好的mib文件放入默认目录中，一般默认目录为/usr/local/net-snmp, 或者放到别的目录中，在配置文件snmpd.conf中增加mibs +/home//mibs/mytrap test-trap.mib，或者直接修改默认的mib路径。
3.使用mib2c -c mib2c.notify.conf TEST-TRAP-MIB::TestTraps命令生成相应的.c和.h文件，如果该命令出错（ERROR: You don't have the SNMP perl module installed. Please obtain
this by getting the latest source release of the net-snmp toolkit from
http://www.net-snmp.org/download/ . Once you download the source and
unpack it, the perl module is contained in the perl/SNMP directory.
See the README file there for instructions.）请正常make make install重新安装net-snmp，原因未知。
生成的.c文件如下
/** Note: this file originally auto-generated by mib2c using* $*/#include
#include
#include
#include "TestTraps.h"extern const oid snmptrap_oid[];
extern const size_t snmptrap_oid_len;int
send_cpuRatioHigh_trap( void )
{netsnmp_variable_list *var_list = NULL;const oid cpuRatioHigh_oid[] = { 1,3,6,1,4,1,1000,1,1 };const oid TestTrapDescription_oid[] = { 1,3,6,1,4,1,1000,1,2,1, 0 };/** Set the snmpTrapOid.0 value*/snmp_varlist_add_variable(&var_list,snmptrap_oid, snmptrap_oid_len,ASN_OBJECT_ID,cpuRatioHigh_oid, sizeof(cpuRatioHigh_oid));/** Add any objects from the trap definition*/snmp_varlist_add_variable(&var_list,TestTrapDescription_oid, OID_LENGTH(TestTrapDescription_oid),ASN_OCTET_STR,/* Set an appropriate value for TestTrapDescription */NULL, 0);/** Add any extra (optional) objects here*//** Send the trap to the list of configured destinations* and clean up*/send_v2trap( var_list );snmp_free_varbind( var_list );return SNMP_ERR_NOERROR;
}
4.修改.c文件，添加函数读取cpu实际使用率和判断是否产生告警函数，每过5秒产生一次报警，这里就直接将cpu使用率定为90，判断告警触发函数写成80，添加初始化函数，注册函数每过一秒读取一下cpu使用率，修改.h文件声明读取cpu使用率函数，修改后的.c函数如下：
/** Note: this file originally auto-generated by mib2c using* $*/#include
#include
#include
#include "TestTraps.h"extern const oid snmptrap_oid[] = {1,3,6,1,6,3,1,1,4,1,0};
const size_t snmptrap_oid_len = OID_LENGTH(snmptrap_oid);void init_TestTraps(void)
{DEBUGMSGTL(("TestTraps","Initializing\n"));snmp_alarm_register(1,SA_REPEAT,read_cpudata_repeat, NULL);
}int
send_cpuRatioHigh_trap( void )
{netsnmp_variable_list *var_list = NULL;const oid cpuRatioHigh_oid[] = { 1,3,6,1,4,1,1000,1,1 };const oid TestTrapDescription_oid[] = { 1,3,6,1,4,1,1000,1,2,1, 0 };static char TestTrapDescription[50];strcpy(TestTrapDescription,"CPU使用率过高");/** Set the snmpTrapOid.0 value*/snmp_varlist_add_variable(&var_list,snmptrap_oid, snmptrap_oid_len,ASN_OBJECT_ID,cpuRatioHigh_oid, sizeof(cpuRatioHigh_oid));/** Add any objects from the trap definition*/snmp_varlist_add_variable(&var_list,TestTrapDescription_oid, OID_LENGTH(TestTrapDescription_oid),ASN_OCTET_STR,/* Set an appropriate value for TestTrapDescription */NULL, 0);/** Add any extra (optional) objects here*//** Send the trap to the list of configured destinations* and clean up*/send_v2trap( var_list );snmp_free_varbind( var_list );return SNMP_ERR_NOERROR;
}void judge_send_cputrap(int cpu)
{static unsigned int cputrap_clientreg = 0;if(cpu > 80){if(cputrap_clientreg == 0){send_cpuRatioHigh_trap();cputrap_clientreg = snmp_alarm_register(5,SA_REPEAT,send_cpuRatioHigh_trap,NULL);}}else{if(cputrap_clientreg != 0){snmp_alarm_unregister(cputrap_clientreg);cputrap_clientreg = 0;}}
}void read_cpudata_repeat(unsigned int clientreg, void *clientarg)
{int cpu = 90;judge_send_cputrap(cpu);
} 5. .然后把相应的.c和.h文件添加到net-snmp源码里的 agent/mibgroup路径下，在configure的时候添加 --with-mib-modules="TestTrap" 选项，如果有多个table，则可以再mibgroup中创建一个文件夹例如testMIB文件夹，然后把相应的.c和.h文件都移到testMIB文件夹下，然后在mibgroup路径下新建一个test.h文件，添加config_require(testMIB/TestTable);依次添加，编译的时候添加configure选项为--weith-mib-modules="test" 则可以一次全部编译；最后make make install
6. 配置trap触发环境，在snmpd.conf添加trap2sink localhost或者trap2sink 127.0.0.1:162，重新启动snmpd 并用-c执行snmpd.conf
然后新建snmptrapd的配置文件snmptrapd.conf添加authcommunity log,execute,net public，为了能清楚看到trap的打印消息用命令
snmptrapd -d -f -Lo -c snmptrapd.conf启动snmptrapd
则每过5秒可以看到trap返回来的告警信息；
注：本人的一点见解，不足之处可以多多交流指正；
本文来自互联网用户投稿，文章观点仅代表作者本人，不代表本站立场，不承担相关法律责任。如若转载，请注明出处。 如若内容造成侵权/违法违规/事实不符，请点击【内容举报】进行投诉反馈！