snmp agent 表格实现（子代理方式实现）

前奏参见如下：
http://blog.sina.com.cn/s/blog_8f3de3250100xhao.html http://blog.csdn.net/hepeng597/article/details/8782868 http://blog.csdn.net/rheostat/article/details/8172580
问题解决：
http://bbs.csdn.net/topics/340248598
实现：

/*

* Note: this file originally auto-generated by mib2c using

* $

*/

#include <net-snmp/net-snmp-config.h>

#include <net-snmp/net-snmp-includes.h>

#include <net-snmp/agent/net-snmp-agent-includes.h>

#include "dpiProject.h"

#define NNN 30

#define STRMAX 200

#define COLUMN_MIN 1

#define COLUMN_MAX 11

struct dpiTaskTable_entry *

dpiTaskTable_createEntry(u_long gnTaskId, char *gnTaskName, size_t gnTaskName_len);

/** Initializes the dpiProject module */

void

init_dpiProject(void)

{

/* here we initialize all the tables we're planning on supporting */

initialize_table_dpiTaskTable();

}

/** Initialize the dpiTaskTable table by defining its contents and how it's structured */

void

initialize_table_dpiTaskTable(void)

{

const oid dpiTaskTable_oid[] = {1,3,6,1,4,1,22222,0,1,0,0};

const size_t dpiTaskTable_oid_len = OID_LENGTH(dpiTaskTable_oid);

netsnmp_handler_registration *reg;

netsnmp_iterator_info *iinfo;

netsnmp_table_registration_info *table_info;

DEBUGMSGTL(("dpiProject:init", "initializing table dpiTaskTable\n"));

reg = netsnmp_create_handler_registration(

"dpiTaskTable", dpiTaskTable_handler,

dpiTaskTable_oid, dpiTaskTable_oid_len,

HANDLER_CAN_RONLY

);

table_info = SNMP_MALLOC_TYPEDEF( netsnmp_table_registration_info );

netsnmp_table_helper_add_indexes(table_info,

ASN_UNSIGNED, /* index: gnTaskId */

0);

//定义最大最小列数

table_info->min_column = COLUMN_MIN;

table_info->max_column = COLUMN_MAX;



iinfo = SNMP_MALLOC_TYPEDEF( netsnmp_iterator_info );

iinfo->get_first_data_point = dpiTaskTable_get_first_data_point;

iinfo->get_next_data_point = dpiTaskTable_get_next_data_point;

iinfo->table_reginfo = table_info;



netsnmp_register_table_iterator( reg, iinfo );

netsnmp_inject_handler_before( reg,

netsnmp_get_cache_handler(DPITASKTABLE_TIMEOUT,

dpiTaskTable_load, dpiTaskTable_free,

dpiTaskTable_oid, dpiTaskTable_oid_len),

TABLE_ITERATOR_NAME);

/* Initialise the contents of the table here */

//初始化表格

dpiTaskTable_createEntry(1, "dpi agent1", strlen("dpi agent1"));

dpiTaskTable_createEntry(2, "dpi agent1", strlen("dpi agent1"));

dpiTaskTable_createEntry(3, "dpi agent1", strlen("dpi agent1"));

}

/* Typical data structure for a row entry */

//总共11列

struct dpiTaskTable_entry {

/* Index values */

//u_long gnTaskId;

/* Column values */

u_long gnTaskId;

char gnTaskName[NNN];

size_t gnTaskName_len;

//char gnTaskState[NNN];

//size_t gnTaskState_len;

//u_long gnTaskCpuUsage;

//u_long gnTaskMemoryUsed;

//char gnTaskStartTime[NNN];

//size_t gnTaskStartTime_len;

//char gnTaskUpTime[NNN];

//size_t gnTaskUpTime_len;

/* Illustrate using a simple linked list */

int valid;

struct dpiTaskTable_entry *next;

};

struct dpiTaskTable_entry *dpiTaskTable_head;

/* create a new row in the (unsorted) table */

struct dpiTaskTable_entry *

dpiTaskTable_createEntry(u_long gnTaskId, char *gnTaskName, size_t gnTaskName_len)

{

struct dpiTaskTable_entry *entry;

entry = SNMP_MALLOC_TYPEDEF(struct dpiTaskTable_entry);

if (!entry)

return NULL;

entry->gnTaskId = gnTaskId;

snmp_log(LOG_ERR,"entry->gnTaskId(%d)\n", entry->gnTaskId);

//实现创建表

entry->gnTaskName_len = gnTaskName_len;

strncpy(entry->gnTaskName, gnTaskName, gnTaskName_len);

entry->next = dpiTaskTable_head;

dpiTaskTable_head = entry;

return entry;

}

/* remove a row from the table */

void

dpiTaskTable_removeEntry( struct dpiTaskTable_entry *entry ) {

struct dpiTaskTable_entry *ptr, *prev;

if (!entry)

return; /* Nothing to remove */

for ( ptr = dpiTaskTable_head, prev = NULL;

ptr != NULL;

prev = ptr, ptr = ptr->next ) {

if ( ptr == entry )

break;

}

if ( !ptr )

return; /* Can't find it */

if ( prev == NULL )

dpiTaskTable_head = ptr->next;

else

prev->next = ptr->next;

SNMP_FREE( entry ); /* XXX - release any other internal resources */

}

/* Example cache handling - set up linked list from a suitable file */

int

dpiTaskTable_load( netsnmp_cache *cache, void *vmagic ) {

FILE *fp;

struct dpiTaskTable_entry *this;

char buf[STRMAX];

/* The basic load routine template assumes that the data to

be reported is held in a file - with one row of the file

for each row of the table.

If your data is available via a different API, you

should amend this initial block (and the control of the

'while' loop) accordingly.

'XXX' marks where the template is incomplete and

code will definitely need to be added. */

fp = fopen( "/data/for/dpiTaskTable", "r" );

if ( !fp ) {

return -1;

}

while ( fgets( buf, STRMAX, fp )) {

this = SNMP_MALLOC_TYPEDEF( struct dpiTaskTable_entry );

/* XXX - Unpick 'buf' to extract the individual field values

and then populate the 'this' data structure with them */

this->next = dpiTaskTable_head;

dpiTaskTable_head = this; /* Iterate helper is fine with unordered lists! */

}

fclose(fp);

return 0; /* OK */

}

void

dpiTaskTable_free( netsnmp_cache *cache, void *vmagic ) {

struct dpiTaskTable_entry *this, *that;

for ( this = dpiTaskTable_head; this; this=that ) {

that = this->next;

SNMP_FREE( this ); /* XXX - release any other internal resources */

}

dpiTaskTable_head = NULL;

}

/* Example iterator hook routines - using 'get_next' to do most of the work */

netsnmp_variable_list *

dpiTaskTable_get_first_data_point(void **my_loop_context,

void **my_data_context,

netsnmp_variable_list *put_index_data,

netsnmp_iterator_info *mydata)

{

*my_loop_context = dpiTaskTable_head;

return dpiTaskTable_get_next_data_point(my_loop_context, my_data_context,

put_index_data, mydata );

}

netsnmp_variable_list *

dpiTaskTable_get_next_data_point(void **my_loop_context,

void **my_data_context,

netsnmp_variable_list *put_index_data,

netsnmp_iterator_info *mydata)

{

struct dpiTaskTable_entry *entry = (struct dpiTaskTable_entry *)*my_loop_context;

netsnmp_variable_list *idx = put_index_data;

if ( entry ) {

snmp_set_var_typed_integer( idx, ASN_UNSIGNED, entry->gnTaskId );

idx = idx->next_variable;

*my_data_context = (void *)entry;

*my_loop_context = (void *)entry->next;

return put_index_data;

} else {

return NULL;

}

}

/** handles requests for the dpiTaskTable table */

int

dpiTaskTable_handler(

netsnmp_mib_handler *handler,

netsnmp_handler_registration *reginfo,

netsnmp_agent_request_info *reqinfo,

netsnmp_request_info *requests) {

netsnmp_request_info *request;

netsnmp_table_request_info *table_info;

struct dpiTaskTable_entry *table_entry;

DEBUGMSGTL(("dpiProject:handler", "Processing request (%d)\n", reqinfo->mode));

switch (reqinfo->mode) {

/*

* Read-support (also covers GetNext requests)

*/

case MODE_GET:

for (request=requests; request; request=request->next) {

table_entry = (struct dpiTaskTable_entry *)

netsnmp_extract_iterator_context(request);

table_info = netsnmp_extract_table_info( request);



switch (table_info->colnum) {

case COLUMN_GNTASKID:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_integer( request->requestvb, ASN_UNSIGNED,

table_entry->gnTaskId);

break;

case COLUMN_GNTASKNAME:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,

table_entry->gnTaskName,

table_entry->gnTaskName_len);

break;

#if 0

case COLUMN_GNTASKSTATE:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,

table_entry->gnTaskState,

table_entry->gnTaskState_len);

break;

case COLUMN_GNTASKCPUUSAGE:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_integer( request->requestvb, ASN_UNSIGNED,

table_entry->gnTaskCpuUsage);

break;

case COLUMN_GNTASKMEMORYUSED:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_integer( request->requestvb, ASN_UNSIGNED,

table_entry->gnTaskMemoryUsed);

break;

case COLUMN_GNTASKSTARTTIME:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,

table_entry->gnTaskStartTime,

table_entry->gnTaskStartTime_len);

break;

case COLUMN_GNTASKUPTIME:

if ( !table_entry ) {

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHINSTANCE);

continue;

}

snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,

table_entry->gnTaskUpTime,

table_entry->gnTaskUpTime_len);

break;

#endif

default:

netsnmp_set_request_error(reqinfo, request,

SNMP_NOSUCHOBJECT);

break;

}

}

break;

}

return SNMP_ERR_NOERROR;

}

说明：

主要是通过m2c 工具生成.c.h文件

1.生成代码模板：变量：env MIBS="+/usr/local/share/snmp/mibs/XXX-MIB.txt" mib2c xxx(对应xxx.c,xxx.h)

表格：env MIBS="+/usr/local/share/snmp/mibs/XXX-MIB.txt" mib2c -c mib2c.iterate.conf xxx(对应xxx.c,xxx.h)

2.修改模板代码。通过devInfo_handler模块提供的api

模板代码流程：init_dpiProject-》initialize_table_xxxTable-》xxxTable_createEntry

修改处：

1.在initialize_table_xxxTable修改表格列数最小最大值

2.initialize_table_xxxTable加人xxxTable_createEntry初始化

3.在xxxTable_createEntry实现表格数据获取（过devInfo_handler模块提供的api）

有三种实现集成到net snmp当中的方式：静态、动态、子代理。本模块采用子代理方式