Ding Jie Niu-Winpcap source code complete decryption series sequel (10)

Set read Timeout:

Packetsetreadtimeout (p-> adapter, p-> Md. Timeout );

Boolean packetsetreadtimeout (lpadapter adapterobject, int timeout)

{

Boolean result;

Trace_enter ("packetsetreadtimeout ");

 

Adapterobject-> readtimeout = timeout;

 

# Ifdef have_wanpacket_api

If (adapterobject-> flags = info_flag_ndiswan_adapter)

{

Result = wanpacketsetreadtimeout (adapterobject-> pwanadapter, timeout );

Trace_exit ("packetsetreadtimeout ");

Return result;

}

# Endif // have_wanpacket_api

 

# Ifdef have_npfim_api

If (adapterobject-> flags = info_flag_npfim_device)

{

//

// Convert the timestamps to Windows like format (0 = immediate,-1 (infinite) = infinite)

//

If (timeout =-1) Timeout = 0;

Else if (timeout = 0) Timeout = infinite;

Result = (Boolean) g_npfimhandlers.npfimsetreadtimeout (adapterobject-> npfimhandle, timeout );

Trace_exit ("packetsetreadtimeout ");

Return result;

}

# Endif // have_npfim_api

 

# Ifdef have_airpcap_api

//

// Timeout with airpcap is handled at user level

//

If (adapterobject-> flags = info_flag_airpcap_card)

{

Trace_exit ("packetsetreadtimeout ");

Return true;

}

# Endif // have_airpcap_api

 

# Ifdef have_dag_api

// Under Dag, we simply store the timeout value and then

If (adapterobject-> flags & info_flag_dag_card)

{

If (timeout =-1)

{

// Tell Dag card to return immediately

Adapterobject-> dagreadtimeout. TV _sec = 0;

Adapterobject-> dagreadtimeout. TV _usec = 0;

}

Else

{

If (timeout = 0)

{

// Tell the Dag card to wait forvever

Adapterobject-> dagreadtimeout. TV _sec =-1;

Adapterobject-> dagreadtimeout. TV _usec =-1;

}

Else

{

// Set the timeout for the Dag card

Adapterobject-> dagreadtimeout. TV _sec = timeout/1000;

Adapterobject-> dagreadtimeout. TV _usec = (timeout * 1000) % 1000000;

}

}

Trace_exit ("packetsetreadtimeout ");

Return true;

}

# Endif // have_dag_api

 

If (adapterobject-> flags = info_flag_ndis_adapter)

{

Result = true;

}

Else

{

//

// If we are here, it's an unsupported adapter type!

//

Trace_print1 ("request to set read timeout on an unknown device type (% u)", adapterobject-> flags );

Result = false;

}

 

Trace_exit ("packetsetreadtimeout ");

Return result;

}

 

From the source code, it is found that the read timeout setting is not passed through deviceiocontrol just like setting the kernel buffer. That is to say, setting the timeout will stop the application and will not be passed down, however, in NPF, I found the Code related to read Timeout:

# Define biocsrtimeout 7416

 

Case biocsrtimeout: // set the timeout on the read CILS

Trace_message (packet_debug_timeout, "biocsrtimeout ");

If (irpsp-> parameters. deviceiocontrol. inputbufferlength <sizeof (ulong ))

{

Set_failure_buffer_small ();

Break;

}

 

Timeout = * (Pulong) IRP-> associatedirp. systembuffer );

If (timeout = (ulong)-1)

Open-> timeout. quadpart = (Longlong) Immediate;

Else

{

Open-> timeout. quadpart = (Longlong) Timeout;

Open-> timeout. quadpart * = 10000;

Open-> timeout. quadpart =-open-> timeout. quadpart;

}

 

Trace_message1 (packet_debug_parts, "Read timeout set to % i64d", open-> timeout. quadpart );

Set_result_success (0 );

Break;

 

The npf_read READ function also contains:

Occupation = 0;

 

For (I = 0; I <g_ncpu; I ++)

Occupation + = (open-> size-open-> cpudata [I]. Free );

// See if the buffer is full enough to be copied

If (occupation <= open-> mintocopy * g_ncpu | open-> mode & mode_dump)

{

If (open-> readevent! = NULL)

{

// Wait until some packets arrive or the timeout expires

If (open-> timeout. quadpart! = (Longlong) Immediate)

Kewaitforsingleobject (open-> readevent,

Userrequest,

Kernelmode,

True,

(Open-> timeout. quadpart = (Longlong) 0 )? Null: & (open-> timeout ));

 

Keclearevent (open-> readevent );

}

 

How is the timeout in the driver passed in! I searched for biocsrtimeout and found it in packetntx \ driver in NPF. SYS. I didn't have it in both wpcap and packet databases! Surprised! Who knows? in Windows XP, the driver under packetntx should be used!