hostname to ip

[FanOfGun]

Hi, I need to convert hostname to ip in Linux, how can I do this? Snx in advance.

[Shardik]

The following example code displays all IP addresses belonging to a given host name. I have tested the cross-platform code successfully on these operating systems:
- Kubuntu 12.04 x64 with PB 5.11 x64 in ASCII and Unicode mode
- MacOS X 10.6.8 (Snow Leopard) with PB 5.11 x86 and x64 in ASCII and Unicode mode
- Windows 7 SP1 x64 with PB 5.11 x86 and x64 in ASCII and Unicode mode

Code: Select all

CompilerIf Defined(HOSTENT, #PB_Structure) = #False
  Structure hostent
    *h_name
    *h_aliases
    h_addrtype.L
    h_length.L
    *h_addr_list
  EndStructure
CompilerEndIf

InitNetwork()

Procedure GetIPAddressesFromHostname(Hostname.S)
  Protected *HostInfos.hostent
  Protected *HostnameBuffer

  *HostNameBuffer = AllocateMemory(StringByteLength(Hostname, #PB_Ascii))
  PokeS(*HostnameBuffer, Hostname, MemorySize(*HostnameBuffer), #PB_Ascii)
  *HostInfos = gethostbyname_(*HostnameBuffer)
  FreeMemory(*HostnameBuffer)
 
  If *HostInfos = 0
    Debug "Error: unable to find host name!"
  Else
    Debug "Hostname: " + PeekS(*HostInfos\h_name, -1, #PB_Ascii)

    If *HostInfos\h_length = 4
      IPType = #PB_Network_IPv4
    Else
      IPType = #PB_Network_IPv6
    EndIf
   
    Debug "IP addresses:"
    *IP = *HostInfos\h_addr_list
   
    While PeekI(*IP) <> 0
      Debug IPString(PeekI(PeekI(*IP)), IPType)
      *IP + SizeOf(Integer)
    Wend
  EndIf

  Debug ""
EndProcedure

GetIPAddressesFromHostname("www.google.com")
GetIPAddressesFromHostname("www.purebasic.com")

Update: I have modified the previous code to also run on Windows.

[Bisonte]

the function

Code: Select all

gethostbyname_(*HostnameBuffer)

is crossplatform ???

[Shardik]

the function

Code: Select all

gethostbyname_(*HostnameBuffer)

is crossplatform ???

No, it's a Unix API function. But the core of MacOS X is a BSD Unix, therefore most Unix API functions also work for MacOS X...

[ts-soft]

No, it's a Unix API function. But the core of MacOS X is a BSD Unix, therefore most Unix API functions also work for MacOS X...

And it is a windows-API

[Shardik]

And it is a windows-API

Too slow...
Thomas is right. Before being able to reboot from MacOS into Windows 7 and being able to test, he posted already his remark. When looking up the structure hostent I wondered already why the structure was also described in a MSDN link...

I modified my above code example to also run in Windows without any modification.

[Bisonte]

I'm impressed The first API call that does on all OS the same ...

[blueznl]

I could use some help on this one, or perhaps slightly related. I'm updating some old code, and in it I found this:

Code: Select all

  buffer_p = AllocateMemory(Len(name)+1)
  PokeS(buffer_p,name,-1,#PB_Ascii)
  bip_p = gethostbyname_(buffer_p)
  FreeMemory(buffer_p)
  If bip_p <> 0
    ProcedureReturn PeekL(PeekL(PeekL(bip_p+12)))
  Else
    ProcedureReturn 0
  EndIf

I didn't write it myself and I haven't got a clue where I stole it

Anyway, the above works fine on Win32 but not on Win64. I suspect it's the PeekL stuff...

In other words, how to retrieve the BIP (not the IP) from a name on Win64?

[Shardik]

Anyway, the above works fine on Win32 but not on Win64. I suspect it's the PeekL stuff...

In other words, how to retrieve the BIP (not the IP) from a name on Win64?

Your BIP (the result your procedure returns) is the first IP address of the requested host name. In order to work on a 64 bit OS you have to change

Code: Select all

    ProcedureReturn PeekL(PeekL(PeekL(bip_p+12)))

to

Code: Select all

    ProcedureReturn PeekI(PeekI(PeekI(bip_p+24)))

However I would strongly advice to use the HOSTENT structure so you don't have to care about 32 or 64 bit systems:

Code: Select all

InitNetwork()

Procedure Get1stIPAddressOfHostName(name.S)
  buffer_p = AllocateMemory(Len(name)+1)
  PokeS(buffer_p,name,-1,#PB_Ascii)
  *bip_p.HOSTENT = gethostbyname_(buffer_p)
  FreeMemory(buffer_p)
  If *bip_p <> 0
    ProcedureReturn PeekI(PeekI(*bip_p\h_addr_list))
  Else
    ProcedureReturn 0
  EndIf
EndProcedure

MessageRequester("Info", "1st IP address of www.purebasic.com: " +
  IPString(Get1stIPAddressOfHostName("www.purebasic.com"), #PB_Network_IPv4))

[bbanelli]

I'm impressed The first API call that does on all OS the same ...

Winsock API follows POSIX socket implementation to very high extent, up to some hassle regarding initialization and cleanup.