snmpd 子代理模式编译测试

1、参考链接

1）Net-snmp添加子代理示例

https://blog.csdn.net/eyf0917/article/details/39546651

2、操作步骤

1）网络拷贝下面的文件

http://www.net-snmp.org/tutorial/tutorial-5/toolkit/mib_module/NET-SNMP-TUTORIAL-MIB.txt

http://www.net-snmp.org/tutorial/tutorial-5/toolkit/demon/nstAgentSubagentObject.c

http://www.net-snmp.org/tutorial/tutorial-5/toolkit/demon/nstAgentSubagentObject.h

2）使用net-snmp-config 生成中间代码，然后使用gcc来编译它

./net-snmp-config --compile-subagent mysubagent nstAgentSubagentObject.c

报错：

root@sun-PC:~/share/work/tools/snmpd/mibs# ./net-snmp-config --compile-subagent mysubagent nstAgentSubagentObject.c
generating the temporary code file: netsnmptmp.3261.c
void init_nstAgentSubagentObject(void);
checking for init_nstAgentSubagentObject in nstAgentSubagentObject.c
init_nstAgentSubagentObject(void)
checking for shutdown_nstAgentSubagentObject in nstAgentSubagentObject.c
running: arm-marvell-linux-gnueabi-gcc -fno-strict-aliasing -g -O2 -Ulinux -Dlinux=linux -I. -I/usr/local/include -o mysubagent netsnmptmp.3261.c nstAgentSubagentObject.c -L/usr/local/lib -lnetsnmpmibs -lnetsnmpagent -lnetsnmp -lnetsnmpmibs -ldl -lnetsnmpagent -lnetsnmp -lrt
netsnmptmp.3261.c:2:38: error: net-snmp/net-snmp-config.h: No such file or directory
netsnmptmp.3261.c:6:40: error: net-snmp/net-snmp-includes.h: No such file or directory
netsnmptmp.3261.c:7:52: error: net-snmp/agent/net-snmp-agent-includes.h: No such file or directory
netsnmptmp.3261.c:21: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'stop_server'
netsnmptmp.3261.c: In function 'usage':
netsnmptmp.3261.c:37: warning: incompatible implicit declaration of built-in function 'fprintf'
netsnmptmp.3261.c:37: error: 'stderr' undeclared (first use in this function)
netsnmptmp.3261.c:37: error: (Each undeclared identifier is reported only once

已经安装了net-snmp-devel，/usr/include/net-snmp/ 路径下也有相关的头文件。

我们重新定义头文件路径：

export C_INCLUDE_PATH="/home/sun/share/work/tools/snmpd/net-snmp-5.7.3/include"
export LDFLAGS="/home/sun/share/work/tools/snmpd/net-snmp-5.7.3/include/net-snmp/library"

3）再次编译依然报错

generating the temporary code file: netsnmptmp.32646.c
void init_nstAgentSubagentObject(void);
checking for init_nstAgentSubagentObject in ./nstAgentSubagentObject.c
init_nstAgentSubagentObject(void)
checking for shutdown_nstAgentSubagentObject in ./nstAgentSubagentObject.c
running: arm-marvell-linux-gnueabi-gcc -fno-strict-aliasing -g -O2 -Ulinux -Dlinux=linux -I. -I/usr/local/include -o mysubagent netsnmptmp.32646.c ./nstAgentSubagentObject.c -L/usr/local/lib -lnetsnmpmibs -lnetsnmpagent -lnetsnmp -lnetsnmpmibs -ldl -lnetsnmpagent -lnetsnmp -lrt
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmpmibs
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmpagent
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmp
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmpmibs
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmpagent
/home/sun/share/work/tools/arm-linux-gcc/armv7-marvell-linux-gnueabi-softfp/bin/../lib/gcc/arm-marvell-linux-gnueabi/4.4.5/../../../../arm-marvell-linux-gnueabi/bin/ld: cannot find -lnetsnmp
collect2: ld returned 1 exit status

6）上述报错信息是缺少动态 .so库文件；

7）net-snmp5.7.3 路径下没有发现 .so文件。可能是没有编译 net-snmp-devel 这个的原因，下载编译，找不到源码包。

8）按照Ubuntu下的net-snmp-devel 工具编译，查找库文件路径： /usr/lib/x86_64-linux-gnu

libsnmp.so -> libsnmp.so.30.0.3
libsnmp.so.30 -> libsnmp.so.30.0.3
libnetsnmpagent.so -> libnetsnmpagent.so.30.0.3
libnetsnmpagent.so.30 -> libnetsnmpagent.so.30.0.3

9）编译snmpd的时候加上了 --prefix 选项

./configure --host=arm-marvell-linux-gnueabi --with-cc=arm-marvell-linux-gnueabi-gcc --with-ar=arm-marvell-linux-gnueabi-ar 
--disable-shared --disable-scripts --with-endianness=little --disable-ipv6 --disable-manuals --disable-ucd-snmp-compatibility 
--enable-as-needed --disable-embedded-perl --prefix=/home/sun/share/work/tools/bin/snmp

在安装的路径下面重新执行 net-snmp-devel 操作，编译完成；

10）执行以下测试命令

snmpd -f -Le -d -c /etc/snmpd/snmpd.conf -M /etc/snmpd/mibs --rwcommunity=public --master=agentx --rwcommunity=public --master=agentx &
./mysubagent -f -Lo &

本地运行mysubagent 会报以下错误信息

Warning: Failed to connect to the agentx master agent ([NIL]):

11）snmpd.conf增加以下内容（和前面命令中的--master=agentx应该是一个作用）

master agentx

master 是说该snmpd以主代理方式运行，目前主代理snmpd只支持agentx类型，而我们要开发的程序是一种子代理（subagent），是需要连snmpd的master agent的。

12）本地运行 snmpget

./snmpget -v 2c -M /etc/snmpd/mibs -c public localhost NET-S
NMP-TUTORIAL-MIB::nstAgentSubagentObject.0
snmpget: Unknown host (localhost) (Resource temporarily unavailable)

服务器运行 snmpget/snmpwalk

snmpget -v2c -c public 10.13.113.205 NET-SNMP-TUTORIAL-MIB::nstAgentSubagentObject.0
NET-SNMP-TUTORIAL-MIB::nstAgentSubagentObject.0: Unknown Object Identifier

本地运行snmpget 报错的原因应该是没有运行snmp服务；

远端snmpd服务器获取模块失败的原因是没有NET-SNMP-TUTORIAL-MIB 文件；

13）将上面的NET-SNMP-TUTORIAL-MIB.txt 文件拷贝到 /home/sun/.snmp/mibs 目录中，Ubuntu中执行命令成功

root@# snmpget -v 2c -c public 10.13.113.205 NET-SNMP-TUTORIAL-MIB::nstAgentSubagentObject.0
Bad operator (html): At line 128 in /home/sun/.snmp/mibs/NET-SNMP-TUTORIAL-MIB.txt
NET-SNMP-TUTORIAL-MIB::nstAgentSubagentObject.0 = INTEGER: 2

3、整理一下子代理模式snmpd需要的程序和配置文件完整收录

1）需要的程序和文件

snmpd 程序、snmpd.conf配置文件、编译的子代理程序 xx；

新增子代理接口文件：XX-MIB.txt。放在snmp服务器侧；

2）运行脚本和命令

agent 端（注意：使用子代理模式，snmpd程序不能编译 mini-agent选项）

snmpd -f -Le -d -c /etc/snmpd/snmpd.conf &
./mysubagent -f -Lo &
snmpd -f -c /etc/snmpd/snmpd.conf & ##不指定mibs文件会报错误，但是不影响
./mysubagent -f &

服务器端

snmpget -v 2c -c public 10.13.113.205 NET-SNMP-TUTORIAL-MIB::nstAgentSubagentObject.0

3）尝试压缩snmpd的体积（去除MIB接口，保留子代理模式）。