SNMP 的table

1. 设计MIB文件mytableTest-MIB.txt：

   myTestTable DEFINITIONS ::= BEGIN
   
   IMPORTS
       OBJECT-GROUP, MODULE-COMPLIANCE, NOTIFICATION-GROUP
           FROM SNMPv2-CONF
       enterprises, Integer32, Unsigned32, OBJECT-TYPE, MODULE-IDENTITY,
       NOTIFICATION-TYPE
           FROM SNMPv2-SMI
       DisplayString
           FROM SNMPv2-TC
       dell-OID-three
       FROM dellRX-MIB;
   
   -- 1.3.6.1.4.1.10000
       myTable-MIB MODULE-IDENTITY
       LAST-UPDATED "201412151450Z"
       ORGANIZATION
           "Actiontec Shenzhen team Surpas"
       CONTACT-INFO
           "Surpas HC(editor)
           Email: <[email protected]>"
       DESCRIPTION
           "For Dell project MIB pdmGeneral."
       ::= { enterprises 10000 }
   
   --testID OBJECT IDENTIFIER ::= { pdmGeneral 2 }
   
   --1.3.6.1.4.1.10000.1
   testTableRoot OBJECT IDENTIFIER ::= { myTable-MIB 1 }
   
   --1.3.6.1.4.1.10000.1.1
   tcTable OBJECT-TYPE
       SYNTAX SEQUENCE OF TcEntry
       MAX-ACCESS not-accessible
       STATUS current
       ::= { testTableRoot 1 }
   
   --1.3.6.1.4.1.10000.1.1.1
   tcEntry OBJECT-TYPE
       SYNTAX     TcEntry
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
          "Information about a particular current UDP endpoint."
       INDEX   { tcIndex }--很重要，snmpwalk时的节点号。
       ::= { tcTable 1 }
   
   TcEntry ::= SEQUENCE {
       tcIndex        Interger32
       tcString    DisplayString (SIZE (0..100)),
       tcinteger    Integer32
       }
   
   --1.3.6.1.4.1.10000.1.1.1.1
   tcIndex OBJECT-TYPE
       SYNTAX     Integer32
       MAX-ACCESS not-accessible
       STATUS     current
       DESCRIPTION
              "The address type of accepted."
       DEFVAL { "xxx table Index xxx!" }
       ::= { tcEntry 1 }
   
   --1.3.6.1.4.1.10000.1.1.1.2
   tcString OBJECT-TYPE
       SYNTAX     DisplayString (SIZE (0..100))
       MAX-ACCESS read-write
       STATUS     current
       DESCRIPTION
              "The address type of accepted."
       DEFVAL { "xxx table row string1 xxx!" }
       ::= { tcEntry 2 }
   
   --1.3.6.1.4.1.10000.1.1.1.3
   tcInteger OBJECT-TYPE
       SYNTAX     Integer32
       MAX-ACCESS read-write
       STATUS     current
       DESCRIPTION
              "The address type of accepted."
       DEFVAL { 6543 }
       ::= { tcEntry 3 }
   END
   

2. 将MIB文件mytableTest-MIB.txt放到MIB search path: /home/actiontec/.snmp/mibs:/usr/local/share/snmp/mibs并且在目录/usr/local/etc/snmp:/usr/local/share/snmp:/usr/local/lib/snmp:/home/actiontec/.snmp:/var/net-snmp添加snmp.conf文件，添加内容：

   #mibs +/home/actiontec/.snmp/mibs/xxx.txt
   mibs +/home/actiontec/.snmp/mibs/mytableTest-MIB.txt
   

3. 使用snmptranslate -Tp -IR myTestTable::testTableRoot(前提mytableTest-MIB.txt放到MIB search path: /home/actiontec/.snmp/mibs:/usr/local/share/snmp/mibs下)或者用snmptranslate -Tp -IR testTableRoot（mytableTest-MIB.txt放到MIB search path: /home/actiontec/.snmp/mibs:/usr/local/share/snmp/mibs并且在目录/usr/local/etc/snmp:/usr/local/share/snmp:/usr/local/lib/snmp:/home/actiontec/.snmp:/var/net-snmp添加snmp.conf文件添加内容mibs +/home/actiontec/.snmp/mibs/mytableTest-MIB.txt）查看有无错误。

   +--testTableRoot(1)
      |
      +--tcTable(1)
         |
         +--tcEntry(1)
            |  Index: tcIndex
            |
            +-- ---- Integer32 tcIndex(1)
            +-- -RW- String    tcString(2)
            |        Textual Convention: DisplayString
            |        Size: 0..100
            +-- -RW- Integer32 tcInteger(3)
   

4. 生成代码mib2c -c mib2c.iterate.conf myTestTable::testTableRoot或者mib2c -c mib2c.iterate.conf testTableRoot
   

   选择1时提供一个缓存来提取数据，一定时间后将更新一次数据，2每次更新
   

5. 编译代码net-snmp-config --compile-subagent Test testTableRoot.c，设计是否有误
   

6. 将testTableRoot.c和头文件放到agent/mibgroup/newdir中。建立文件agent/mibgroup/newdir.h添加内容：config_require(newdir/testTableRoot);用于./configure时用。

7. testTableRoot.c代码
   

   /*
    * 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 "testTableRoot.h"
   #define MY_ERROR_FILE "/home/actiontec/install-dir/net-snmp/errdir/errtablefile.txt"
   
   /** Initializes the testTableRoot module */
   void
   init_testTableRoot(void)
   {
     /* here we initialize all the tables we're planning on supporting */
       initialize_table_tcTable();
   }
   
   //  # Determine the first/last column names
   
   /** Initialize the tcTable table by defining its contents and how it's structured */
   void
   initialize_table_tcTable(void)
   {
       const oid tcTable_oid[] = {1,3,6,1,4,1,10000,1,1};
       const size_t tcTable_oid_len   = OID_LENGTH(tcTable_oid);
       netsnmp_handler_registration    *reg;
       netsnmp_iterator_info           *iinfo;
       netsnmp_table_registration_info *table_info;
   
       DEBUGMSGTL(("testTableRoot:init", "initializing table tcTable\n"));
   
       reg = netsnmp_create_handler_registration(
                 "tcTable",     tcTable_handler,
                 tcTable_oid, tcTable_oid_len,
                 HANDLER_CAN_RWRITE
                 );
   
       table_info = SNMP_MALLOC_TYPEDEF( netsnmp_table_registration_info );
       netsnmp_table_helper_add_indexes(table_info,
                              ASN_INTEGER,  /* index: tcIndex */
                              0);
       table_info->min_column = COLUMN_TCSTRING;
       table_info->max_column = COLUMN_TCINTEGER;
       
       iinfo = SNMP_MALLOC_TYPEDEF( netsnmp_iterator_info );
       iinfo->get_first_data_point = tcTable_get_first_data_point;
       iinfo->get_next_data_point  = tcTable_get_next_data_point;
       iinfo->table_reginfo        = table_info;
       
       netsnmp_register_table_iterator( reg, iinfo );
   
       tcTable_createEntry(1, "xiaolongxxxwo", sizeof("xiaolongxxxwo"), 556);

       //这句话很重要​，必须创建一个表对象才可以访问他
       /* Initialise the contents of the table here */
   }
   
       /* Typical data structure for a row entry */
   struct tcTable_entry {
       /* Index values */
       long tcIndex;
   
       /* Column values */
       char tcString[64];
       size_t tcString_len;
       char old_tcString[64];
       size_t old_tcString_len;
       long tcInteger;
       long old_tcInteger;
   
       /* Illustrate using a simple linked list */
       int   valid;
       struct tcTable_entry *next;
   };
   
   struct tcTable_entry  *tcTable_head;
   
   /* create a new row in the (unsorted) table */
   struct tcTable_entry *
   tcTable_createEntry(
                    long  tcIndex,
                    char* tcString,
                    size_t tcString_len,
                    long  tcInteger
                   ) {
       struct tcTable_entry *entry;
       struct tcTable_entry *entryNext;    
       entry = SNMP_MALLOC_TYPEDEF(struct tcTable_entry);
       entryNext = SNMP_MALLOC_TYPEDEF(struct tcTable_entry);
       if (!entry)
           return NULL;
   //胡乱添加的，这里设计了1，2节点，一会看效果就知道作用了
       entry->tcIndex = tcIndex;
       memcpy(entry->tcString, tcString, tcString_len);
       entry->tcString_len = tcString_len;
       entry->tcInteger = tcInteger;
   
       entryNext->tcIndex = 2;
       memcpy(entryNext->tcString, "abcdefg", sizeof("abcdefg"));
       entryNext->tcString_len = sizeof("abcdefg");
       entryNext->tcInteger = 321;    
       
       entry->next = entryNext;
       entryNext->next = tcTable_head;
       tcTable_head = entry;
       return entry;
   }
   
   /* remove a row from the table */
   void
   tcTable_removeEntry( struct tcTable_entry *entry ) {
       struct tcTable_entry *ptr, *prev;
   
       if (!entry)
           return;    /* Nothing to remove */
   
       for ( ptr  = tcTable_head, prev = NULL;
             ptr != NULL;
             prev = ptr, ptr = ptr->next ) {
           if ( ptr == entry )
               break;
       }
       if ( !ptr )
           return;    /* Can't find it */
   
       if ( prev == NULL )
           tcTable_head = ptr->next;
       else
           prev->next = ptr->next;
   
       SNMP_FREE( entry );   /* XXX - release any other internal resources */
   }
   
   
   /* Example iterator hook routines - using 'get_next' to do most of the work */
   netsnmp_variable_list *
   tcTable_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 = tcTable_head;
       return tcTable_get_next_data_point(my_loop_context, my_data_context,
                                       put_index_data,  mydata );
   }
   
   netsnmp_variable_list *
   tcTable_get_next_data_point(void **my_loop_context,
                             void **my_data_context,
                             netsnmp_variable_list *put_index_data,
                             netsnmp_iterator_info *mydata)
   {
       struct tcTable_entry *entry = (struct tcTable_entry *)*my_loop_context;
       netsnmp_variable_list *idx = put_index_data;
   
       if ( entry ) {
           snmp_set_var_typed_integer( idx, ASN_INTEGER, entry->tcIndex );
           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 tcTable table */
   int
   tcTable_handler(
       netsnmp_mib_handler               *handler,
       netsnmp_handler_registration      *reginfo,
       netsnmp_agent_request_info        *reqinfo,
       netsnmp_request_info              *requests) {
       int ret;
       netsnmp_request_info       *request;
       netsnmp_table_request_info *table_info;
       struct tcTable_entry          *table_entry;
       FILE *fd;
       DEBUGMSGTL(("myTable_MIB:handler", "Processing request (%d)\n", reqinfo->mode));
       fd = fopen(MY_ERROR_FILE, "ar");
       if(fd>0)
       {
           fprintf(fd, "surpas:%s,%d,mode=%d!\n", __FILE__, __LINE__, reqinfo->mode);
           fclose(fd);
       }
   
       switch (reqinfo->mode) {
           /*
            * Read-support (also covers GetNext requests)
            */
       case MODE_GET:
           for (request=requests; request; request=request->next) {
               table_entry = (struct tcTable_entry *)
                                 netsnmp_extract_iterator_context(request);
               table_info  =     netsnmp_extract_table_info(      request);
       
               switch (table_info->colnum) {
               case COLUMN_TCSTRING:
                   if ( !table_entry ) {
                       netsnmp_set_request_error(reqinfo, request,
                                                 SNMP_NOSUCHINSTANCE);
                       continue;
                   }
                   snmp_set_var_typed_value( request->requestvb, ASN_OCTET_STR,
                                             table_entry->tcString,
                                             table_entry->tcString_len);
                   break;
               case COLUMN_TCINTEGER:
                   if ( !table_entry ) {
                       netsnmp_set_request_error(reqinfo, request,
                                                 SNMP_NOSUCHINSTANCE);
                       continue;
                   }
                   snmp_set_var_typed_integer( request->requestvb, ASN_INTEGER,
                                               table_entry->tcInteger);
                   break;
               default:
                   netsnmp_set_request_error(reqinfo, request,
                                             SNMP_NOSUCHOBJECT);
                   break;
               }
           }
           break;
   
           /*
            * Write-support
            */
       case MODE_SET_RESERVE1:
           for (request=requests; request; request=request->next) {
               table_entry = (struct tcTable_entry *)
                                 netsnmp_extract_iterator_context(request);
               table_info  =     netsnmp_extract_table_info(      request);
       
               switch (table_info->colnum) {
               case COLUMN_TCSTRING:
               /* or possibly 'netsnmp_check_vb_type_and_size' */
                   ret = netsnmp_check_vb_type_and_max_size(
                             request->requestvb, ASN_OCTET_STR, sizeof(table_entry->tcString));
                   if ( ret != SNMP_ERR_NOERROR ) {
                       netsnmp_set_request_error( reqinfo, request, ret );
                       return SNMP_ERR_NOERROR;
                   }
                   break;
               case COLUMN_TCINTEGER:
                   /* or possibly 'netsnmp_check_vb_int_range' */
                   ret = netsnmp_check_vb_int( request->requestvb );
                   if ( ret != SNMP_ERR_NOERROR ) {
                       netsnmp_set_request_error( reqinfo, request, ret );
                       return SNMP_ERR_NOERROR;
                   }
                   break;
               default:
                   netsnmp_set_request_error( reqinfo, request,
                                              SNMP_ERR_NOTWRITABLE );
                   return SNMP_ERR_NOERROR;
               }
           }
           break;
   
       case MODE_SET_RESERVE2:
           break;
   
       case MODE_SET_FREE:
           break;
   
       case MODE_SET_ACTION:
           for (request=requests; request; request=request->next) {
               table_entry = (struct tcTable_entry *)
                                 netsnmp_extract_iterator_context(request);
               table_info  =     netsnmp_extract_table_info(      request);
       //here change our own configure
               switch (table_info->colnum) {
               case COLUMN_TCSTRING:
                   memcpy( table_entry->old_tcString,
                           table_entry->tcString,
                           sizeof(table_entry->tcString));
                   table_entry->old_tcString_len =
                           table_entry->tcString_len;
                   memset( table_entry->tcString, 0,
                           sizeof(table_entry->tcString));
                   memcpy( table_entry->tcString,
                           request->requestvb->val.string,
                           request->requestvb->val_len);
                   table_entry->tcString_len =
                           request->requestvb->val_len;
                   break;
               case COLUMN_TCINTEGER:
                   table_entry->old_tcInteger = table_entry->tcInteger;
                   table_entry->tcInteger     = *request->requestvb->val.integer;
                   break;
               }
           }
           break;
   
       case MODE_SET_UNDO:
           for (request=requests; request; request=request->next) {
               table_entry = (struct tcTable_entry *)
                                 netsnmp_extract_iterator_context(request);
               table_info  =     netsnmp_extract_table_info(      request);
       
               switch (table_info->colnum) {
               case COLUMN_TCSTRING:
                   memcpy( table_entry->tcString,
                           table_entry->old_tcString,
                           sizeof(table_entry->tcString));
                   memset( table_entry->old_tcString, 0,
                           sizeof(table_entry->tcString));
                   table_entry->tcString_len =
                           table_entry->old_tcString_len;
                   break;
               case COLUMN_TCINTEGER:
                   table_entry->tcInteger     = table_entry->old_tcInteger;
                   table_entry->old_tcInteger = 0;
                   break;
               }
           }
           break;
   
       case MODE_SET_COMMIT:
           break;
       }
       return SNMP_ERR_NOERROR;
   }
   

8. 我们先看下7的效果，在create里面可以添加列表的：

   myTestTable::tcString.1 = STRING: xiaolongxxxwo.
   myTestTable::tcString.2 = STRING: abcdefg.
   myTestTable::tcInteger.1 = INTEGER: 556
   myTestTable::tcInteger.2 = INTEGER: 321
   SNMPv2-SMI::enterprises.10000.1.1.1.2.1 = Hex-STRING: 78 69 61 6F 6C 6F 6E 67 78 78 78 77 6F 00
   SNMPv2-SMI::enterprises.10000.1.1.1.2.2 = Hex-STRING: 61 62 63 64 65 66 67 00
   SNMPv2-SMI::enterprises.10000.1.1.1.3.1 = INTEGER: 556
   SNMPv2-SMI::enterprises.10000.1.1.1.3.2 = INTEGER: 321
   

9. 完成了，先进行编译：./configure --with-default-snmp-version="3"  --with-sys-contact="@@no.where"  --with-sys-location="Unknown" --with-logfile="/var/log/snmpd.log"  --with-persistent-directory="/var/net-snmp" --with-mib-modules="newdir" --enable-mini-agent(mini版)

   make

   sudo make install

10. 可以使用了