NETSTAT

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The NETSTAT tool outputs useful information retrieved from the stack, such as the routing table, the ARP table, the UDP socket table, and the TCP vector table. A user can pick the information he is interested in and output it in the preferred way through the call back functions.

The NETSTAT API consists of a set of data structures, a function tfNetStat() that enumerates the table entries, a callback interface (ttNtEntryCBFuncPtr) that handles each entry, and a set of helper functions. The helper functions facilitate the writing of user call back functions. They provide the table header string and convert a NETSTAT entry into a string.

• tfNtGetArpHeaderStr()
• tfNtGetNatHeaderStr()
• tfNtGetRteHeaderStr()
• tfNtGetTcpHeaderStr()
• tfNtGetUdpHeaderStr()
• tfNtArpEntryToStr()
• tfNtNatEntryToStr()
• tfNtRteEntryToStr()
• tfNtTcpEntryToStr()
• tfNtUdpEntryToStr()

These data structures are defined for NETSTAT:

(These data structures hold a mapped copy of the internal stack data, they are only for the output purpose, modifying these data has no effect on the internal data.)

• ttNtArpEntry
• ttNtNatEntry
• ttNtRteEntry
• ttNtTcpEntry
• ttNtUdpEntry
• ttNtEntryU

Note:

In order to use the NETSTAT tool, TM_USE_NETSTAT must be #defined in <trsystem.h>.

Function Calls

tfNetStat() tfNtGetArpHeaderStr() tfNtGetNatHeaderStr() tfNtGetRteHeaderStr() tfNtGetTcpHeaderStr() tfNtGetUdpHeaderStr()

ttNtEntryCBFuncPtr() tfNtArpEntryToStr() tfNtNatEntryToStr() tfNtRteEntryToStr() tfNtTcpEntryToStr() tfNtUdpEntryToStr()

Examples

Below is an example of how to implement the NETSTAT APIs to print the NETSTAT TCP table. More examples may be found in the examples/txtelntd.c module of the distribution.

Warning:

Note: Since printf is non-reentrant, it therefore should never be used in a preemptive environment.

tfxNtTcpEntryCBPrintf() is defined as below:

 
int tfxNtTcpEntryCBPrintf(
    ttNtEntryUPtr       ntEntryUPtr,
    ttUserGenericUnion  genParam1,
    ttUserGenericUnion  genParam2)
{
 
    char    buffer[TM_NT_ENTRY_STR_LEN];
    int     entryStrLen;
 
    genParam1 = genParam1;
    genParam2 = genParam2;
    entryStrLen = TM_NT_ENTRY_STR_LEN;
 
    if(tfNtTcpEntryToStr(&ntEntryUPtr->ntTcpEntry, buffer,  &entryStrLen) != NULL)
    {
        printf("%s\n", buffer);
    }
 
/*  
 * return TM_ENOERROR to ask tfNetStat to call back with more entries 
 * return TM_ENOENT to ask tfNetStat to stop calling back
 */
    return TM_ENOERROR;
}
 

Below is a example of how to use tfNetStat() and the call back function defined above to print out the TCP socket table.

 
#include <trsocket.h>
main()
{
    char                buffer[TM_NT_ENTRY_STR_LEN];
    int                 headerStrLen;
    ttUserGenericUnion  genUnion;
 
...
 
/* print the TCP socket table using NETSTAT tools */
    printf("\n------\nTCP sockets\n------\n");
    headerStrLen = TM_NT_ENTRY_STR_LEN;
    if(tfNtGetTcpHeaderStr(buffer,&headerStrLen)!= NULL)
    {
        printf("%s\n", buffer);
    }
    errorCode = tfNetStat(TM_NT_TABLE_TCP,
                          tfxNtTcpEntryCBPrintf,
                          genUnion,
                          genUnion);
}
 

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