[fpc-pascal] Help Reading SIP Messages.

lloyd thomas lloydie.t at googlemail.com
Wed Jan 6 13:59:58 CET 2010


No Joy, I get exactly the same error. But putting the following at the start
of the unit got me to the next error (which I managed to fix ptr = pointer)
{$ifdef FPC}
{$MODE delphi}
{$endif}


2010/1/6 ik <idokan at gmail.com>

> Try the following (see inline for the answer):
>
>
> On Wed, Jan 6, 2010 at 13:30, lloyd thomas <lloydie.t at googlemail.com>wrote:
>
>> Well I have made a start using smeone elese libpcap inplementation, but
>> have bump into my first issue and because of my lack of skill I am not sure
>> how to code round it. Any Ideas?
>> I get the following errors
>>
>> PlibCap\Pcap.pas(207,13) Error: Illegal qualifier
>> PlibCap\Pcap.pas(207,13) Hint: may be pointer dereference is missing
>> PlibCap\Pcap.pas(207,13) Fatal: Syntax error, "THEN" expected but
>> "identifier ADAPTER" found
>>
>> In this section (so far)
>>      procedure CleanUp;
>>      begin
>>        if P.Adapter <> nil then PacketCloseAdapter(P.adapter); //error
>> here
>>
>
> if Assigned(P.Adapter) then PacketCloseAdapter(P.adapter);
>
>         if P.buffer<>nil then FreeMem(P.buffer,PcapBufSize); //but suspect
>> I would get one here as well
>>
> if Assigned(P.buffer) then FreeMem(P.buffer,PcapBufSize);
>
>
> The reason is that afaik assigned checks if the field is both nil and
> allocated, and if it's not nil but not allocated i will return false as
> well.
> Another thing is that I think you needed () around the comparing code.
>
>
>        Freemem(P,SizeOf(Tpcap));
>>      end,
>>
>> (which I think has something to do with this)
>> type
>>   TWinVersion = (wv_WinS,
>>                  wv_Win9x,              //Added by Lars Peter
>> Christiansen.
>>                  wv_WinNT,              //Eases the process of determing
>> the
>>                  wv_Win2000,             //platform and do proper
>> instructions
>>                  wv_WinXP,               //I.e : Char vs. WideChar issue
>>                  wv_Unknown );
>>
>>
>>
>>   PPcap_Stat = ^TPcap_stat;
>>   Tpcap_stat = record
>>     ps_recv,                          //* number of packets received */
>>     ps_drop,                         //* number of packets dropped */
>>     ps_ifdrop : LongWord;                //* drops by interface not
>> supported */
>>   end;
>>
>>   TPcap_sf = record                      // Save file for offline reading.
>>     rfile : HFILE;
>>     swapped:integer;
>>     version_major : integer;
>>     Version_Minor : integer;
>>     base : Pointer;
>>   end;
>>
>>   TPcap_md = record
>>     Stat : TPcap_stat;
>>     use_bpf : integer;
>>     TotPkts  : LongWord;               // Can owerflow after 79hours on
>> ethernet
>>     TotAccepted:LongWord;              // accepted by filter/sniffer
>>     TotDrops : LongWord;               // dropped packets
>>     TotMissed: Longword;               // missed by i/f during this run
>>     OrigMissed:LongWord;               // missed by i/f before this run
>>   end;
>>
>>   PPcap_PktHdr = ^Tpcap_pkthdr;        // Wrapped Drivers packetHeader
>>   TPcap_pkthdr = record
>>     ts     : TUnixTimeVal;             // Time of capture
>>     CapLen,                            // captured length
>>     Len    : Integer;                  // actual length of packet
>>   end;
>>
>>   PPcap = ^TPcap;                      // THE MAIN INTERFACE HANDLE
>>   TPcap = record                       // used with allmost all Pcap
>> calls.
>>     Adapter:Padapter;
>>     Packet :PPacket;                   // Global Driver packet. kind of a
>> buffer
>>     snapshot:integer;
>>     linktype:integer;                  // Type and speed of net
>>     tzoff   :integer;                   // timezone offset
>>     offset  :integer;
>>     sf      :Tpcap_sf;                 // Save file
>>     md      :Tpcap_md;                 // Diagnostics
>>     //READ BUFFER
>>     bufsize :integer;
>>     buffer  :Pointer; //*u_char
>>     bp      :Pointer; //*u_char
>>     cc      :integer;
>>     //Place holder for pcap_next().
>>     pkt     :Pointer; //*U_char
>>     //Placeholder for filter code if bpf not in kernel.
>>     fcode   :Tbpf_program;
>>     errbuf  : array [0..PCAP_ERRBUF_SIZE-1] of char;  //Last error message
>>   end;
>>
>>
>> 2010/1/5 ik <idokan at gmail.com>
>>
>>> use libpcap (and bind it to FPC and share with us all :)) and then you
>>> can sniff packets (that's the easiest way I know).
>>>
>>>
>>> Ido
>>> http://ik.homelinux.org/
>>>
>>>
>>> On Tue, Jan 5, 2010 at 16:48, lloyd thomas <lloydie.t at googlemail.com>wrote:
>>>
>>>> Also came across this which uses pcap, but seems to be delphi only
>>>> http://www.magsys.co.uk/delphi/magmonsock.asp
>>>>
>>>> is there something similar for fpc?
>>>>
>>>> 2010/1/5 lloyd thomas <lloydie.t at googlemail.com>
>>>>
>>>> OK. I wish to monitor and record calls between a SIP endpoint and SIP
>>>>> Gateway. At the moment I am doing that by connecting the SIP endpoint and my
>>>>> machine to an ethernet hub so that I can see all the traffic.
>>>>> In the first instance I just need to correctly capture, read and
>>>>> interprete the SIP messages so that I can make an informed decision which
>>>>> RDP packets to capture.
>>>>>
>>>>> Then I suppose I will have an even harder task capturing the RDP
>>>>> packets and joining both legs together (my coding skills is not great)!
>>>>>
>>>>> Lloydie T
>>>>>
>>>>> 2010/1/5 ik <idokan at gmail.com>
>>>>>
>>>>> Hello,
>>>>>>
>>>>>> SIP first of all uses UDP most of the times (and rarely TCP) .
>>>>>> It only create a tunnel that other protocols such as RDP and SDP are
>>>>>> going inside.
>>>>>>
>>>>>> Can you explain a bit more what exactly do you wish to implement (i'm
>>>>>> not sure that I understand) ?
>>>>>>
>>>>>> Ido
>>>>>>
>>>>>> http://ik.homelinux.org/
>>>>>>
>>>>>>
>>>>>> On Tue, Jan 5, 2010 at 15:08, lloyd thomas <lloydie.t at googlemail.com>wrote:
>>>>>>
>>>>>>> Please forgive my ignorance regarding the project I am about to
>>>>>>> embark on.
>>>>>>> Need some advice on Lnet and capturing SIP RTP data to file. In the
>>>>>>> first instance I just need to work with the sip messages. I believe the SIP
>>>>>>> messages are similar to HTTP. I am using wireshark to understand how the SIP
>>>>>>> messages are processed, but I am not sure how to capture and read each frame
>>>>>>> (wireshark speak) using Lnet.
>>>>>>>
>>>>>>> (FYI:
>>>>>>> http://en.wikipedia.org/wiki/Session_Initiation_Protocol#SIP_network_elements
>>>>>>> )
>>>>>>>
>>>>>>> For instance the following is from frame 12 (935 bytes)
>>>>>>>
>>>>>>> ----------------------------------------------------------------------------------------------
>>>>>>> INVITE sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200> SIP/2.0
>>>>>>> Via:SIP/2.0/UDP 192.168.91.190:5060;rport;branch=z9hG4bK83570061
>>>>>>> From:"Lloyd" <sip:1000 at 192.168.91.200 <sip%3A1000 at 192.168.91.200>
>>>>>>> >;tag=4b428357-2fa-1ec5d4e
>>>>>>> To:<sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200>>
>>>>>>> Contact:"Lloyd" <sip:1000 at 192.168.91.190:5060;transport=UDP>
>>>>>>> Call-ID:83570000-4ce59f27 at 192.168.91.200<Call-ID%3A83570000-4ce59f27 at 192.168.91.200>
>>>>>>> Subject:sip phone call
>>>>>>> CSeq:2112045024 INVITE
>>>>>>> User-Agent:Mitel-5212-SIP-Phone 07.02.00.04 08000F24BEE5
>>>>>>> Allow:INVITE,ACK,CANCEL,BYE,OPTIONS,REFER,NOTIFY,PRACK,UPDATE
>>>>>>> Allow-Events:talk,hold,conference
>>>>>>> Supported:timer,100rel,replaces
>>>>>>> Session-Expires: 1800
>>>>>>> Min-SE: 90
>>>>>>> Max-Forwards:70
>>>>>>> Content-Type:application/sdp
>>>>>>> Content-Length:247
>>>>>>>
>>>>>>> v=0
>>>>>>> o=1000 1262650963 1262650962 IN IP4 192.168.91.190
>>>>>>> s=SIP Call
>>>>>>> c=IN IP4 192.168.91.190
>>>>>>> t=0 0
>>>>>>> a=sendrecv
>>>>>>> m=audio 20036 RTP/AVP 0 8 18 96
>>>>>>> a=rtpmap:0 PCMU/8000
>>>>>>> a=rtpmap:8 PCMA/8000
>>>>>>> a=rtpmap:18 G729/8000
>>>>>>> a=rtpmap:96 telephone-event/8000
>>>>>>>
>>>>>>> -----------------------------------------------------------------------------------------------
>>>>>>>
>>>>>>> I get a response from the sip server on frame 13 (371 bytes)
>>>>>>>
>>>>>>> ----------------------------------------------------------------------------------------------
>>>>>>> SIP/2.0 100 Trying
>>>>>>> Via: SIP/2.0/UDP 192.168.91.190:5060
>>>>>>> ;rport=5060;branch=z9hG4bK83570061
>>>>>>> From: "Lloyd" <sip:1000 at 192.168.91.200 <sip%3A1000 at 192.168.91.200>
>>>>>>> >;tag=4b428357-2fa-1ec5d4e
>>>>>>> To: <sip:1002 at 192.168.91.200 <sip%3A1002 at 192.168.91.200>>
>>>>>>> Call-ID: 83570000-4ce59f27 at 192.168.91.200
>>>>>>> CSeq: 2112045024 INVITE
>>>>>>> User-Agent: FreeSWITCH-mod_sofia/1.0.trunk-15355M
>>>>>>> Content-Length: 0
>>>>>>>
>>>>>>> -----------------------------------------------------------------------------------------------
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>>>>>>> http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
>>>>>> http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>>>>>>
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
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>>>> http://lists.freepascal.org/mailman/listinfo/fpc-pascal
>>>>
>>>
>>>
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>>>
>>
>>
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>>
>
>
> _______________________________________________
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