Source code of Windows XP (NT5)
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/*++
Copyright (c) 1998, Microsoft Corporation
Module Name:
dnsio.c
Abstract:
This module contains code for the DNS allocator's network I/O completion
routines.
Author:
Abolade Gbadegesin (aboladeg) 9-Mar-1998
Revision History:
--*/
#include "precomp.h"
#pragma hdrstop
#include "dnsmsg.h"
VOID
DnsReadCompletionRoutine(
ULONG ErrorCode,
ULONG BytesTransferred,
PNH_BUFFER Bufferp
)
/*++
Routine Description:
This routine is invoked upon completion of a read operation
on a datagram socket bound to the DNS server UDP port.
The message read is validated and processed; the processing may involve
creating a query-record and forwarding the query to a server, or
matching a response to an existing query-record and forwarding the
response to the appropriate client.
Arguments:
ErrorCode - Win32 status code for the I/O operation
BytesTransferred - number of bytes in 'Bufferp'
Bufferp - holds data read from the datagram socket
Return Value:
none.
Environment:
Runs in the context of an RTUTILS.DLL worker-thread which has just
dequeued an I/O completion packet from the common I/O completion port
with which our datagram sockets are associated.
A reference to the component will have been made on our behalf
by 'NhReadDatagramSocket'.
--*/
{
ULONG Error;
PDNS_HEADER Headerp;
PDNS_INTERFACE Interfacep;
PROFILE("DnsReadCompletionRoutine");
do {
//
// There are two cases where we don't process the message;
// (a) the I/O operation failed
// (b) the interface is no longer active
// In case (a), we repost the buffer; in case (b), we do not.
//
Interfacep = (PDNS_INTERFACE)Bufferp->Context;
//
// First look for an error code
//
if (ErrorCode) {
NhTrace(
TRACE_FLAG_IO,
"DnsReadCompletionRoutine: error %d for read-context %x",
ErrorCode,
Bufferp->Context
);
//
// See if the interface is still active
//
ACQUIRE_LOCK(Interfacep);
if (!DNS_INTERFACE_ACTIVE(Interfacep)) {
RELEASE_LOCK(Interfacep);
NhReleaseBuffer(Bufferp);
} else {
RELEASE_LOCK(Interfacep);
EnterCriticalSection(&DnsInterfaceLock);
if (!DNS_REFERENCE_INTERFACE(Interfacep)) {
LeaveCriticalSection(&DnsInterfaceLock);
NhReleaseBuffer(Bufferp);
} else {
LeaveCriticalSection(&DnsInterfaceLock);
//
// Repost the buffer for another read operation
//
do {
Error =
NhReadDatagramSocket(
&DnsComponentReference,
Bufferp->Socket,
Bufferp,
DnsReadCompletionRoutine,
Bufferp->Context,
Bufferp->Context2
);
//
// A connection-reset error indicates that our last
// *send* could not be delivered at its destination.
// We could hardly care less; so issue the read again,
// immediately.
//
} while (Error == WSAECONNRESET);
if (Error) {
ACQUIRE_LOCK(Interfacep);
DnsDeferReadInterface(Interfacep, Bufferp->Socket);
RELEASE_LOCK(Interfacep);
DNS_DEREFERENCE_INTERFACE(Interfacep);
NhWarningLog(
IP_DNS_PROXY_LOG_RECEIVE_FAILED,
Error,
"%I",
NhQueryAddressSocket(Bufferp->Socket)
);
NhReleaseBuffer(Bufferp);
}
}
}
break;
}
//
// Now see if the interface is operational
//
ACQUIRE_LOCK(Interfacep);
if (!DNS_INTERFACE_ACTIVE(Interfacep)) {
RELEASE_LOCK(Interfacep);
NhReleaseBuffer(Bufferp);
NhTrace(
TRACE_FLAG_IO,
"DnsReadCompletionRoutine: interface %d inactive",
Interfacep->Index
);
break;
}
RELEASE_LOCK(Interfacep);
//
// Now look at the message
//
Headerp = (PDNS_HEADER)Bufferp->Buffer;
if (Headerp->IsResponse == DNS_MESSAGE_QUERY) {
DnsProcessQueryMessage(
Interfacep,
Bufferp
);
} else {
DnsProcessResponseMessage(
Interfacep,
Bufferp
);
}
} while(FALSE);
DNS_DEREFERENCE_INTERFACE(Interfacep);
DEREFERENCE_DNS();
} // DnsReadCompletionRoutine
VOID
DnsWriteCompletionRoutine(
ULONG ErrorCode,
ULONG BytesTransferred,
PNH_BUFFER Bufferp
)
/*++
Routine Description:
This routine is invoked upon completion of a write-operation
on a datagram socket bound to the DNS server UDP port.
The write-context for all writes is a 'DNS_QUERY'. Our handling
is dependent on whether the message written was a query or a response.
Upon completion of a query, we may need to do a resend if there was
an error. Upon completion of a response, we delete the query-record.
Arguments:
ErrorCode - Win32 status code for the I/O operation
BytesTransferred - number of bytes in 'Bufferp'
Bufferp - holds data read from the datagram socket
Return Value:
none.
Environment:
Runs in the context of an RTUTILS.DLL worker-thread which has just
dequeued an I/O completion packet from the common I/O completion port
with which our datagram sockets are associated.
A reference to the component will have been made on our behalf
by 'NhReadDatagramSocket'.
--*/
{
ULONG Error;
PDNS_HEADER Headerp;
PDNS_INTERFACE Interfacep;
USHORT QueryId;
PDNS_QUERY Queryp;
PULONG Server;
PROFILE("DnsWriteCompletionRoutine");
Interfacep = (PDNS_INTERFACE)Bufferp->Context;
QueryId = (USHORT)Bufferp->Context2;
Headerp = (PDNS_HEADER)Bufferp->Buffer;
ACQUIRE_LOCK(Interfacep);
//
// Obtain the query associated with the send.
//
Queryp = DnsMapResponseToQuery(Interfacep, QueryId);
if (Headerp->IsResponse == DNS_MESSAGE_RESPONSE) {
if (ErrorCode) {
//
// An error occurred sending the message to the client
//
NhTrace(
TRACE_FLAG_DNS,
"DnsWriteCompletionRoutine: error %d response %d interface %d",
ErrorCode,
Queryp ? Queryp->QueryId : -1,
Interfacep->Index
);
NhWarningLog(
IP_DNS_PROXY_LOG_RESPONSE_FAILED,
ErrorCode,
"%I",
NhQueryAddressSocket(Bufferp->Socket)
);
} else if (Queryp && Headerp->ResponseCode == DNS_RCODE_NOERROR) {
//
// We're done with this query since it succeeded; remove it.
//
NhTrace(
TRACE_FLAG_DNS,
"DnsWriteCompletionRoutine: removing query %d interface %d",
Queryp->QueryId,
Interfacep->Index
);
DnsDeleteQuery(Interfacep, Queryp);
}
} else {
if (!ErrorCode) {
//
// No errors, so just return.
//
NhTrace(
TRACE_FLAG_DNS,
"DnsWriteCompletionRoutine: sent query %d interface %d",
Queryp ? Queryp->QueryId : -1,
Interfacep->Index
);
} else {
//
// The query just went out and it failed.
//
NhTrace(
TRACE_FLAG_DNS,
"DnsWriteCompletionRoutine: error %d for query %d interface %d",
ErrorCode,
Queryp ? Queryp->QueryId : -1,
Interfacep->Index
);
NhWarningLog(
IP_DNS_PROXY_LOG_QUERY_FAILED,
ErrorCode,
"%I%I%I",
Queryp ? Queryp->SourceAddress : -1,
Bufferp->WriteAddress.sin_addr.s_addr,
NhQueryAddressSocket(Bufferp->Socket)
);
}
}
RELEASE_LOCK(Interfacep);
DNS_DEREFERENCE_INTERFACE(Interfacep);
NhReleaseBuffer(Bufferp);
DEREFERENCE_DNS();
} // DnsWriteCompletionRoutine