NetBIOS APIs

Hi,

I'm looking for documentation on the Windows Network APIs. In particular, I want to query for the names of all "visible" computers on the network. I've been googling away, but just keep getting Samba referrals!!! I don't know if this information is held locally on my machine, or if I have to query, for example, a WINS server, but in either case I need to know how to achive it!

Apologies for cross-posting, but my thread on the Networking forum has returned a workable, but not particularly elegant solution! (Ping all the addresses in the current network address range. Do a port scan on those that respond to look for SMB ports open and finally do a reverse DNS lookup to get the name.....)

Many thanks,

Paul

P.S. I'm using Code::Blocks and wxWidgets, if that makes any difference.

Give the following a try to see if it works for you.

Code:

---

#include <windows.h>
#include <stdio.h>
#pragma comment(lib,"mpr")
#pragma comment(lib,"wsock32")

int main(void)
{
        NETRESOURCE *pNetworkResource = NULL;
        HANDLE hEnumerate;
        DWORD dwResult;
        DWORD dwSize = 16386;
        DWORD dwNumber = -1;
        char pszGroupName[255] = {0};
        int iLength;
        struct hostent* host = NULL;

        WSADATA wsaData;
        if(WSAStartup(MAKEWORD(2,2),&wsaData) != 0 )
        {
                printf("WSAStartup failed\n");
                return -1;
        }
        if(WNetOpenEnum(RESOURCE_CONTEXT,RESOURCETYPE_ANY,0,NULL,&hEnumerate) != 0)
        {
                printf("WNetOpenEnum failed\n");
                WSACleanup();
                return -1;
        }
        pNetworkResource=(LPNETRESOURCE)GlobalAlloc(GPTR, dwSize);
        if( pNetworkResource == NULL)
        {
                printf("GlobalAlloc failed\n");
                WNetCloseEnum(hEnumerate);
                WSACleanup();
                return -1; 
        }
        WNetEnumResource( hEnumerate, &dwNumber, pNetworkResource, &dwSize);
        for (DWORD dwIndex = 0; dwIndex < dwNumber; dwIndex++)
        {
                if (pNetworkResource[dwIndex].lpRemoteName==NULL)
                        continue;
                iLength = strlen(pNetworkResource[dwIndex].lpRemoteName);
                memset(&pszGroupName, 0, sizeof(pszGroupName));
                // Remove the "\\" prefix
                memcpy(pszGroupName, pNetworkResource[dwIndex].lpRemoteName + 2, iLength - 2);
                host = gethostbyname(pszGroupName);
                if(host != NULL)
                        printf("%s  %s\n", host->h_name, inet_ntoa( *( in_addr *)host->h_addr) );
        }
        GlobalFree(pNetworkResource);
        WNetCloseEnum(hEnumerate);
        WSACleanup();
        return 0;
}

---

Thanks for that :D

I tried putting this into Code::Blocks as a console application. When I compiled I got:

Code:

---

C:\Sourcecode\computers\main.cpp    3    warning:  ignoring #pragma comment
C:\Sourcecode\computers\main.cpp    4    warning:  ignoring #pragma comment
C:\Sourcecode\computers\main.cpp          In function 'main':
C:\Sourcecode\computers\main.cpp    12  warning:  converting of negative value '-0x00000001' to 'DWORD'
C:\Sourcecode\computers\main.cpp    10  warning:  unused variable 'dwResult'
obj\Debug.main.o                          In function 'main':
C:\Sourcecode\computers\main.cpp    18  undefined reference to '_WSAStartup@8'
C:\Sourcecode\computers\main.cpp    23  undefined reference to '_WNetOpenEnumA@20'
C:\Sourcecode\computers\main.cpp    26  undefined reference to '_WSACleanup@0'
C:\Sourcecode\computers\main.cpp    33  undefined reference to '_WNetCloseEnum@4'
C:\Sourcecode\computers\main.cpp    34  undefined reference to '_WSACleanup@0'
C:\Sourcecode\computers\main.cpp    37  undefined reference to '_WNetEnumResource@16'
C:\Sourcecode\computers\main.cpp    46  undefined reference to '_gethostbyname@4'
C:\Sourcecode\computers\main.cpp    48  undefined reference to '_inet_ntoa@4'
C:\Sourcecode\computers\main.cpp    51  undefined reference to '_WNetCloseEnum@4'
C:\Sourcecode\computers\main.cpp    52  undefined reference to '_WSACleanup@0'
                                          === Build Finished: 10 errors, 4  warnings ===

---

I had a play and found I needed to add the wsock32 and mpr libraries to the build myself. Is that correct? Or should the #pragma statements have done it for me?

I'm fairly new to C++ and windows programming, although have experience with other languages. I'm assuming I should have been able to just compile?

Anyway, it worked and did exactly what I need it to do :D

Thanks

Paul

Link the needed libraries, mpr and winsock. Ensure that -lmpr and -lws2_32 get passed to the linker. (Probably under linker options, or something. RTFM for Code::Blocks, it should tell you)

Thanks CH, I kind of managed to (eventually) work that out (hence my edit) although I didn't know about the command-line options being passed to the linker....

I'll have a look at the docs, but sometimes it's difficult to know if it's a Code::Blocks issue, a compiler (MinGW) issue, a basic C++ issue or, with my main app, a wxWidgets issue!!!!

Once I get my head around this stuff, I'm sure I'll be fine (java took a few weeks too ;) ) but at the moment........

Cheers,

Paul

These are specs for the SMB Protocol:
http://msdn.microsoft.com/en-us/library/cc246231.aspx
http://msdn.microsoft.com/en-us/library/cc246482.aspx

And here you can find all other Windows Communication Protocols:
http://msdn.microsoft.com/en-us/library/cc216513.aspx

Took ~5 minutes of searching.. if you know where you have to look ;)

Edit:
These might also be helpful:
http://msdn.microsoft.com/en-us/library/cc197979.aspx

Quote:

---

if you know where you have to look

---

That's the key though, isn't it? All I could find on Google was loads of references to SAMBA and to the existence of an API!

Anyway, thanks for that - all useful stuff.

Paul