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[netbsd-mini2440.git] / external / bsd / bind / dist / lib / isc / win32 / socket.c

/*      $NetBSD$        */

/*
 * Copyright (C) 2004-2009  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000-2003  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* Id: socket.c,v 1.81 2009/11/10 18:31:47 each Exp */

/* This code uses functions which are only available on Server 2003 and
 * higher, and Windows XP and higher.
 *
 * This code is by nature multithreaded and takes advantage of various
 * features to pass on information through the completion port for
 * when I/O is completed.  All sends, receives, accepts, and connects are
 * completed through the completion port.
 *
 * The number of Completion Port Worker threads used is the total number
 * of CPU's + 1. This increases the likelihood that a Worker Thread is
 * available for processing a completed request.
 *
 * XXXPDM 5 August, 2002
 */

#define MAKE_EXTERNAL 1
#include <config.h>

#include <sys/types.h>

#ifndef _WINSOCKAPI_
#define _WINSOCKAPI_   /* Prevent inclusion of winsock.h in windows.h */
#endif

#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <io.h>
#include <fcntl.h>
#include <process.h>

#include <isc/buffer.h>
#include <isc/bufferlist.h>
#include <isc/condition.h>
#include <isc/list.h>
#include <isc/log.h>
#include <isc/mem.h>
#include <isc/msgs.h>
#include <isc/mutex.h>
#include <isc/net.h>
#include <isc/once.h>
#include <isc/os.h>
#include <isc/platform.h>
#include <isc/print.h>
#include <isc/region.h>
#include <isc/socket.h>
#include <isc/stats.h>
#include <isc/strerror.h>
#include <isc/syslog.h>
#include <isc/task.h>
#include <isc/thread.h>
#include <isc/util.h>
#include <isc/win32os.h>

#include <mswsock.h>

#include "errno2result.h"

/*
 * How in the world can Microsoft exist with APIs like this?
 * We can't actually call this directly, because it turns out
 * no library exports this function.  Instead, we need to
 * issue a runtime call to get the address.
 */
LPFN_CONNECTEX ISCConnectEx;
LPFN_ACCEPTEX ISCAcceptEx;
LPFN_GETACCEPTEXSOCKADDRS ISCGetAcceptExSockaddrs;

/*
 * Run expensive internal consistency checks.
 */
#ifdef ISC_SOCKET_CONSISTENCY_CHECKS
#define CONSISTENT(sock) consistent(sock)
#else
#define CONSISTENT(sock) do {} while (0)
#endif
static void consistent(isc_socket_t *sock);

/*
 * Define this macro to control the behavior of connection
 * resets on UDP sockets.  See Microsoft KnowledgeBase Article Q263823
 * for details.
 * NOTE: This requires that Windows 2000 systems install Service Pack 2
 * or later.
 */
#ifndef SIO_UDP_CONNRESET
#define SIO_UDP_CONNRESET _WSAIOW(IOC_VENDOR,12)
#endif

/*
 * Some systems define the socket length argument as an int, some as size_t,
 * some as socklen_t.  This is here so it can be easily changed if needed.
 */
#ifndef ISC_SOCKADDR_LEN_T
#define ISC_SOCKADDR_LEN_T unsigned int
#endif

/*
 * Define what the possible "soft" errors can be.  These are non-fatal returns
 * of various network related functions, like recv() and so on.
 */
#define SOFT_ERROR(e)   ((e) == WSAEINTR || \
                         (e) == WSAEWOULDBLOCK || \
                         (e) == EWOULDBLOCK || \
                         (e) == EINTR || \
                         (e) == EAGAIN || \
                         (e) == 0)

/*
 * Pending errors are not really errors and should be
 * kept separate
 */
#define PENDING_ERROR(e) ((e) == WSA_IO_PENDING || (e) == 0)

#define DOIO_SUCCESS      0       /* i/o ok, event sent */
#define DOIO_SOFT         1       /* i/o ok, soft error, no event sent */
#define DOIO_HARD         2       /* i/o error, event sent */
#define DOIO_EOF          3       /* EOF, no event sent */
#define DOIO_PENDING      4       /* status when i/o is in process */
#define DOIO_NEEDMORE     5       /* IO was processed, but we need more due to minimum */

#define DLVL(x) ISC_LOGCATEGORY_GENERAL, ISC_LOGMODULE_SOCKET, ISC_LOG_DEBUG(x)

/*
 * DLVL(90)  --  Function entry/exit and other tracing.
 * DLVL(70)  --  Socket "correctness" -- including returning of events, etc.
 * DLVL(60)  --  Socket data send/receive
 * DLVL(50)  --  Event tracing, including receiving/sending completion events.
 * DLVL(20)  --  Socket creation/destruction.
 */
#define TRACE_LEVEL             90
#define CORRECTNESS_LEVEL       70
#define IOEVENT_LEVEL           60
#define EVENT_LEVEL             50
#define CREATION_LEVEL          20

#define TRACE           DLVL(TRACE_LEVEL)
#define CORRECTNESS     DLVL(CORRECTNESS_LEVEL)
#define IOEVENT         DLVL(IOEVENT_LEVEL)
#define EVENT           DLVL(EVENT_LEVEL)
#define CREATION        DLVL(CREATION_LEVEL)

typedef isc_event_t intev_t;

/*
 * Socket State
 */
enum {
  SOCK_INITIALIZED,     /* Socket Initialized */
  SOCK_OPEN,            /* Socket opened but nothing yet to do */
  SOCK_DATA,            /* Socket sending or receiving data */
  SOCK_LISTEN,          /* TCP Socket listening for connects */
  SOCK_ACCEPT,          /* TCP socket is waiting to accept */
  SOCK_CONNECT,         /* TCP Socket connecting */
  SOCK_CLOSED,          /* Socket has been closed */
};

#define SOCKET_MAGIC            ISC_MAGIC('I', 'O', 'i', 'o')
#define VALID_SOCKET(t)         ISC_MAGIC_VALID(t, SOCKET_MAGIC)

/*
 * IPv6 control information.  If the socket is an IPv6 socket we want
 * to collect the destination address and interface so the client can
 * set them on outgoing packets.
 */
#ifdef ISC_PLATFORM_HAVEIPV6
#ifndef USE_CMSG
#define USE_CMSG        1
#endif
#endif

/*
 * We really  don't want to try and use these control messages. Win32
 * doesn't have this mechanism before XP.
 */
#undef USE_CMSG

/*
 * Message header for recvmsg and sendmsg calls.
 * Used value-result for recvmsg, value only for sendmsg.
 */
struct msghdr {
        SOCKADDR_STORAGE to_addr;       /* UDP send/recv address */
        int      to_addr_len;           /* length of the address */
        WSABUF  *msg_iov;               /* scatter/gather array */
        u_int   msg_iovlen;             /* # elements in msg_iov */
        void    *msg_control;           /* ancillary data, see below */
        u_int   msg_controllen;         /* ancillary data buffer len */
        int     msg_totallen;           /* total length of this message */
} msghdr;

/*
 * The size to raise the receive buffer to.
 */
#define RCVBUFSIZE (32*1024)

/*
 * The number of times a send operation is repeated if the result
 * is WSAEINTR.
 */
#define NRETRIES 10

struct isc_socket {
        /* Not locked. */
        unsigned int            magic;
        isc_socketmgr_t        *manager;
        isc_mutex_t             lock;
        isc_sockettype_t        type;

        /* Pointers to scatter/gather buffers */
        WSABUF                  iov[ISC_SOCKET_MAXSCATTERGATHER];

        /* Locked by socket lock. */
        ISC_LINK(isc_socket_t)  link;
        unsigned int            references; /* EXTERNAL references */
        SOCKET                  fd;     /* file handle */
        int                     pf;     /* protocol family */
        char                    name[16];
        void *                  tag;

        /*
         * Each recv() call uses this buffer.  It is a per-socket receive
         * buffer that allows us to decouple the system recv() from the
         * recv_list done events.  This means the items on the recv_list
         * can be removed without having to cancel pending system recv()
         * calls.  It also allows us to read-ahead in some cases.
         */
        struct {
                SOCKADDR_STORAGE        from_addr;         // UDP send/recv address
                int             from_addr_len;     // length of the address
                char            *base;             // the base of the buffer
                char            *consume_position; // where to start copying data from next
                unsigned int    len;               // the actual size of this buffer
                unsigned int    remaining;         // the number of bytes remaining
        } recvbuf;

        ISC_LIST(isc_socketevent_t)             send_list;
        ISC_LIST(isc_socketevent_t)             recv_list;
        ISC_LIST(isc_socket_newconnev_t)        accept_list;
        isc_socket_connev_t                    *connect_ev;

        isc_sockaddr_t          address;  /* remote address */

        unsigned int            listener : 1,   /* listener socket */
                                connected : 1,
                                pending_connect : 1, /* connect pending */
                                bound : 1;      /* bound to local addr */
        unsigned int            pending_iocp;   /* Should equal the counters below. Debug. */
        unsigned int            pending_recv;  /* Number of outstanding recv() calls. */
        unsigned int            pending_send;  /* Number of outstanding send() calls. */
        unsigned int            pending_accept; /* Number of outstanding accept() calls. */
        unsigned int            state; /* Socket state. Debugging and consistency checking. */
        int                     state_lineno;  /* line which last touched state */
        int                     in_recovery_cnt; /* avoid recovery loop. */
};

#define _set_state(sock, _state) do { (sock)->state = (_state); (sock)->state_lineno = __LINE__; } while (0)

/*
 * Buffer structure
 */
typedef struct buflist buflist_t;

struct buflist {
        void                    *buf;
        unsigned int            buflen;
        ISC_LINK(buflist_t)     link;
};

/*
 * I/O Completion ports Info structures
 */

static HANDLE hHeapHandle = NULL;
typedef struct IoCompletionInfo {
        OVERLAPPED              overlapped;
        isc_socketevent_t       *dev;  /* send()/recv() done event */
        isc_socket_connev_t     *cdev; /* connect() done event */
        isc_socket_newconnev_t  *adev; /* accept() done event */
        void                    *acceptbuffer;
        DWORD                   received_bytes;
        int                     request_type;
        struct msghdr           messagehdr;
        ISC_LIST(buflist_t)     bufferlist;     /*%< list of buffers */
} IoCompletionInfo;

/*
 * Define a maximum number of I/O Completion Port worker threads
 * to handle the load on the Completion Port. The actual number
 * used is the number of CPU's + 1.
 */
#define MAX_IOCPTHREADS 20

#define SOCKET_MANAGER_MAGIC    ISC_MAGIC('I', 'O', 'm', 'g')
#define VALID_MANAGER(m)        ISC_MAGIC_VALID(m, SOCKET_MANAGER_MAGIC)

struct isc_socketmgr {
        /* Not locked. */
        unsigned int                    magic;
        isc_mem_t                      *mctx;
        isc_mutex_t                     lock;
        isc_stats_t                    *stats;

        /* Locked by manager lock. */
        ISC_LIST(isc_socket_t)          socklist;
        isc_boolean_t                   bShutdown;
        isc_condition_t                 shutdown_ok;
        HANDLE                          hIoCompletionPort;
        int                             maxIOCPThreads;
        HANDLE                          hIOCPThreads[MAX_IOCPTHREADS];
        DWORD                           dwIOCPThreadIds[MAX_IOCPTHREADS];

        /*
         * Debugging.
         * Modified by InterlockedIncrement() and InterlockedDecrement()
         */
        LONG                            totalSockets;
        LONG                            iocp_total;
};

enum {
        SOCKET_RECV,
        SOCKET_SEND,
        SOCKET_ACCEPT,
        SOCKET_CONNECT
};

/*
 * send() and recv() iovec counts
 */
#define MAXSCATTERGATHER_SEND   (ISC_SOCKET_MAXSCATTERGATHER)
#define MAXSCATTERGATHER_RECV   (ISC_SOCKET_MAXSCATTERGATHER)

static isc_threadresult_t WINAPI SocketIoThread(LPVOID ThreadContext);
static void maybe_free_socket(isc_socket_t **, int);
static void free_socket(isc_socket_t **, int);
static isc_boolean_t senddone_is_active(isc_socket_t *sock, isc_socketevent_t *dev);
static isc_boolean_t acceptdone_is_active(isc_socket_t *sock, isc_socket_newconnev_t *dev);
static isc_boolean_t connectdone_is_active(isc_socket_t *sock, isc_socket_connev_t *dev);
static void send_recvdone_event(isc_socket_t *sock, isc_socketevent_t **dev);
static void send_senddone_event(isc_socket_t *sock, isc_socketevent_t **dev);
static void send_acceptdone_event(isc_socket_t *sock, isc_socket_newconnev_t **adev);
static void send_connectdone_event(isc_socket_t *sock, isc_socket_connev_t **cdev);
static void send_recvdone_abort(isc_socket_t *sock, isc_result_t result);
static void queue_receive_event(isc_socket_t *sock, isc_task_t *task, isc_socketevent_t *dev);
static void queue_receive_request(isc_socket_t *sock);
static void hard_recover_receive_request(isc_socket_t *sock);
static void recover_receive_request(isc_socket_t *sock, void **lplpo);

/*
 * This is used to dump the contents of the sock structure
 * You should make sure that the sock is locked before
 * dumping it. Since the code uses simple printf() statements
 * it should only be used interactively.
 */
void
sock_dump(isc_socket_t *sock) {
        isc_socketevent_t *ldev;
        isc_socket_newconnev_t *ndev;

#if 0
        isc_sockaddr_t addr;
        char socktext[256];

        isc_socket_getpeername(sock, &addr);
        isc_sockaddr_format(&addr, socktext, sizeof(socktext));
        printf("Remote Socket: %s\n", socktext);
        isc_socket_getsockname(sock, &addr);
        isc_sockaddr_format(&addr, socktext, sizeof(socktext));
        printf("This Socket: %s\n", socktext);
#endif

        printf("\n\t\tSock Dump\n");
        printf("\t\tfd: %u\n", sock->fd);
        printf("\t\treferences: %d\n", sock->references);
        printf("\t\tpending_accept: %d\n", sock->pending_accept);
        printf("\t\tconnecting: %d\n", sock->pending_connect);
        printf("\t\tconnected: %d\n", sock->connected);
        printf("\t\tbound: %d\n", sock->bound);
        printf("\t\tpending_iocp: %d\n", sock->pending_iocp);
        printf("\t\tsocket type: %d\n", sock->type);

        printf("\n\t\tSock Recv List\n");
        ldev = ISC_LIST_HEAD(sock->recv_list);
        while (ldev != NULL) {
                printf("\t\tdev: %p\n", ldev);
                ldev = ISC_LIST_NEXT(ldev, ev_link);
        }

        printf("\n\t\tSock Send List\n");
        ldev = ISC_LIST_HEAD(sock->send_list);
        while (ldev != NULL) {
                printf("\t\tdev: %p\n", ldev);
                ldev = ISC_LIST_NEXT(ldev, ev_link);
        }

        printf("\n\t\tSock Accept List\n");
        ndev = ISC_LIST_HEAD(sock->accept_list);
        while (ndev != NULL) {
                printf("\t\tdev: %p\n", ldev);
                ndev = ISC_LIST_NEXT(ndev, ev_link);
        }
}

static void
socket_log(int lineno, isc_socket_t *sock, isc_sockaddr_t *address,
           isc_logcategory_t *category, isc_logmodule_t *module, int level,
           isc_msgcat_t *msgcat, int msgset, int message,
           const char *fmt, ...) ISC_FORMAT_PRINTF(9, 10);

/*  This function will add an entry to the I/O completion port
 *  that will signal the I/O thread to exit (gracefully)
 */
static void
signal_iocompletionport_exit(isc_socketmgr_t *manager) {
        int i;
        int errval;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_MANAGER(manager));
        for (i = 0; i < manager->maxIOCPThreads; i++) {
                if (!PostQueuedCompletionStatus(manager->hIoCompletionPort,
                                                0, 0, 0)) {
                        errval = GetLastError();
                        isc__strerror(errval, strbuf, sizeof(strbuf));
                        FATAL_ERROR(__FILE__, __LINE__,
                                isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_FAILED,
                                "Can't request service thread to exit: %s"),
                                strbuf);
                }
        }
}

/*
 * Create the worker threads for the I/O Completion Port
 */
void
iocompletionport_createthreads(int total_threads, isc_socketmgr_t *manager) {
        int errval;
        char strbuf[ISC_STRERRORSIZE];
        int i;

        INSIST(total_threads > 0);
        REQUIRE(VALID_MANAGER(manager));
        /*
         * We need at least one
         */
        for (i = 0; i < total_threads; i++) {
                manager->hIOCPThreads[i] = CreateThread(NULL, 0, SocketIoThread,
                                                manager, 0,
                                                &manager->dwIOCPThreadIds[i]);
                if (manager->hIOCPThreads[i] == NULL) {
                        errval = GetLastError();
                        isc__strerror(errval, strbuf, sizeof(strbuf));
                        FATAL_ERROR(__FILE__, __LINE__,
                                isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_FAILED,
                                "Can't create IOCP thread: %s"),
                                strbuf);
                        exit(1);
                }
        }
}

/*
 *  Create/initialise the I/O completion port
 */
void
iocompletionport_init(isc_socketmgr_t *manager) {
        int errval;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_MANAGER(manager));
        /*
         * Create a private heap to handle the socket overlapped structure
         * The minimum number of structures is 10, there is no maximum
         */
        hHeapHandle = HeapCreate(0, 10 * sizeof(IoCompletionInfo), 0);
        if (hHeapHandle == NULL) {
                errval = GetLastError();
                isc__strerror(errval, strbuf, sizeof(strbuf));
                FATAL_ERROR(__FILE__, __LINE__,
                            isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                           ISC_MSG_FAILED,
                                           "HeapCreate() failed during "
                                           "initialization: %s"),
                            strbuf);
                exit(1);
        }

        manager->maxIOCPThreads = min(isc_os_ncpus() + 1, MAX_IOCPTHREADS);

        /* Now Create the Completion Port */
        manager->hIoCompletionPort = CreateIoCompletionPort(
                        INVALID_HANDLE_VALUE, NULL,
                        0, manager->maxIOCPThreads);
        if (manager->hIoCompletionPort == NULL) {
                errval = GetLastError();
                isc__strerror(errval, strbuf, sizeof(strbuf));
                FATAL_ERROR(__FILE__, __LINE__,
                                isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_FAILED,
                                "CreateIoCompletionPort() failed "
                                "during initialization: %s"),
                                strbuf);
                exit(1);
        }

        /*
         * Worker threads for servicing the I/O
         */
        iocompletionport_createthreads(manager->maxIOCPThreads, manager);
}

/*
 * Associate a socket with an IO Completion Port.  This allows us to queue events for it
 * and have our worker pool of threads process them.
 */
void
iocompletionport_update(isc_socket_t *sock) {
        HANDLE hiocp;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_SOCKET(sock));

        hiocp = CreateIoCompletionPort((HANDLE)sock->fd,
                sock->manager->hIoCompletionPort, (ULONG_PTR)sock, 0);

        if (hiocp == NULL) {
                DWORD errval = GetLastError();
                isc__strerror(errval, strbuf, sizeof(strbuf));
                isc_log_iwrite(isc_lctx,
                                ISC_LOGCATEGORY_GENERAL,
                                ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
                                isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_TOOMANYHANDLES,
                                "iocompletionport_update: failed to open"
                                " io completion port: %s",
                                strbuf);

                /* XXXMLG temporary hack to make failures detected.
                 * This function should return errors to the caller, not
                 * exit here.
                 */
                FATAL_ERROR(__FILE__, __LINE__,
                                isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_FAILED,
                                "CreateIoCompletionPort() failed "
                                "during initialization: %s"),
                                strbuf);
                exit(1);
        }

        InterlockedIncrement(&sock->manager->iocp_total);
}

/*
 * Routine to cleanup and then close the socket.
 * Only close the socket here if it is NOT associated
 * with an event, otherwise the WSAWaitForMultipleEvents
 * may fail due to the fact that the Wait should not
 * be running while closing an event or a socket.
 * The socket is locked before calling this function
 */
void
socket_close(isc_socket_t *sock) {

        REQUIRE(sock != NULL);

        if (sock->fd != INVALID_SOCKET) {
                closesocket(sock->fd);
                sock->fd = INVALID_SOCKET;
                _set_state(sock, SOCK_CLOSED);
                InterlockedDecrement(&sock->manager->totalSockets);
        }
}

static isc_once_t initialise_once = ISC_ONCE_INIT;
static isc_boolean_t initialised = ISC_FALSE;

static void
initialise(void) {
        WORD wVersionRequested;
        WSADATA wsaData;
        int err;
        SOCKET sock;
        GUID GUIDConnectEx = WSAID_CONNECTEX;
        GUID GUIDAcceptEx = WSAID_ACCEPTEX;
        GUID GUIDGetAcceptExSockaddrs = WSAID_GETACCEPTEXSOCKADDRS;
        DWORD dwBytes;

        /* Need Winsock 2.2 or better */
        wVersionRequested = MAKEWORD(2, 2);

        err = WSAStartup(wVersionRequested, &wsaData);
        if (err != 0) {
                char strbuf[ISC_STRERRORSIZE];
                isc__strerror(err, strbuf, sizeof(strbuf));
                FATAL_ERROR(__FILE__, __LINE__, "WSAStartup() %s: %s",
                            isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                           ISC_MSG_FAILED, "failed"),
                            strbuf);
                exit(1);
        }
        /*
         * The following APIs do not exist as functions in a library, but we must
         * ask winsock for them.  They are "extensions" -- but why they cannot be
         * actual functions is beyond me.  So, ask winsock for the pointers to the
         * functions we need.
         */
        sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        INSIST(sock != INVALID_SOCKET);
        err = WSAIoctl(sock,  SIO_GET_EXTENSION_FUNCTION_POINTER,
                 &GUIDConnectEx, sizeof(GUIDConnectEx),
                 &ISCConnectEx, sizeof(ISCConnectEx),
                 &dwBytes, NULL, NULL);
        INSIST(err == 0);

        err = WSAIoctl(sock,  SIO_GET_EXTENSION_FUNCTION_POINTER,
                 &GUIDAcceptEx, sizeof(GUIDAcceptEx),
                 &ISCAcceptEx, sizeof(ISCAcceptEx),
                 &dwBytes, NULL, NULL);
        INSIST(err == 0);

        err = WSAIoctl(sock,  SIO_GET_EXTENSION_FUNCTION_POINTER,
                 &GUIDGetAcceptExSockaddrs, sizeof(GUIDGetAcceptExSockaddrs),
                 &ISCGetAcceptExSockaddrs, sizeof(ISCGetAcceptExSockaddrs),
                 &dwBytes, NULL, NULL);
        INSIST(err == 0);

        closesocket(sock);

        initialised = ISC_TRUE;
}

/*
 * Initialize socket services
 */
void
InitSockets(void) {
        RUNTIME_CHECK(isc_once_do(&initialise_once,
                                  initialise) == ISC_R_SUCCESS);
        if (!initialised)
                exit(1);
}

int
internal_sendmsg(isc_socket_t *sock, IoCompletionInfo *lpo,
                 struct msghdr *messagehdr, int flags, int *Error)
{
        int Result;
        DWORD BytesSent;
        DWORD Flags = flags;
        int total_sent;

        *Error = 0;
        Result = WSASendTo(sock->fd, messagehdr->msg_iov,
                           messagehdr->msg_iovlen, &BytesSent,
                           Flags, (SOCKADDR *)&messagehdr->to_addr,
                           messagehdr->to_addr_len, (LPWSAOVERLAPPED)lpo,
                           NULL);

        total_sent = (int)BytesSent;

        /* Check for errors.*/
        if (Result == SOCKET_ERROR) {
                *Error = WSAGetLastError();

                switch (*Error) {
                case WSA_IO_INCOMPLETE:
                case WSA_WAIT_IO_COMPLETION:
                case WSA_IO_PENDING:
                case NO_ERROR:          /* Strange, but okay */
                        sock->pending_iocp++;
                        sock->pending_send++;
                        break;

                default:
                        return (-1);
                        break;
                }
        } else {
                sock->pending_iocp++;
                sock->pending_send++;
        }

        if (lpo != NULL)
                return (0);
        else
                return (total_sent);
}

static void
queue_receive_request(isc_socket_t *sock) {
        DWORD Flags = 0;
        DWORD NumBytes = 0;
        int total_bytes = 0;
        int Result;
        int Error;
        isc_boolean_t need_recovering = ISC_FALSE;
        WSABUF iov[1];
        IoCompletionInfo *lpo;
        isc_result_t isc_result;

        /*
         * If we already have a receive pending, do nothing.
         */
        if (sock->pending_recv > 0)
                return;

        /*
         * If no one is waiting, do nothing.
         */
        if (ISC_LIST_EMPTY(sock->recv_list))
                return;

        INSIST(sock->recvbuf.remaining == 0);
        INSIST(sock->fd != INVALID_SOCKET);

        iov[0].len = sock->recvbuf.len;
        iov[0].buf = sock->recvbuf.base;

        lpo = (IoCompletionInfo *)HeapAlloc(hHeapHandle,
                                            HEAP_ZERO_MEMORY,
                                            sizeof(IoCompletionInfo));
        RUNTIME_CHECK(lpo != NULL);
        lpo->request_type = SOCKET_RECV;

        sock->recvbuf.from_addr_len = sizeof(sock->recvbuf.from_addr);

        Error = 0;
        Result = WSARecvFrom((SOCKET)sock->fd, iov, 1,
                             &NumBytes, &Flags,
                             (SOCKADDR *)&sock->recvbuf.from_addr,
                             &sock->recvbuf.from_addr_len,
                             (LPWSAOVERLAPPED)lpo, NULL);

        /* Check for errors. */
        if (Result == SOCKET_ERROR) {
                Error = WSAGetLastError();

                switch (Error) {
                case WSA_IO_PENDING:
                        sock->pending_iocp++;
                        sock->pending_recv++;
                        break;

                case ERROR_HOST_UNREACHABLE:
                        if (sock->type == isc_sockettype_udp) {
                                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "WSARecvFrom ERROR_HOST_UNREACHABLE: trying to recover");
                                need_recovering = ISC_TRUE;
                                break;
                        } else
                                goto fail;

                case WSAENETRESET:
                        if (sock->type == isc_sockettype_udp) {
                                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "WSARecvFrom WSAENETRESET: trying to recover");
                                need_recovering = ISC_TRUE;
                                break;
                        } else
                                goto fail;

                case WSAECONNRESET:
                        if (sock->type == isc_sockettype_udp) {
                                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "WSARecvFrom WSAECONNRESET: trying to recover");
                                need_recovering = ISC_TRUE;
                                break;
                        } else
                                goto fail;

                default:
                fail:
                        isc_result = isc__errno2result(Error);
                        if ((isc_result == ISC_R_UNEXPECTED) ||
                            (isc_result == ISC_R_CONNECTIONRESET) ||
                            (isc_result == ISC_R_HOSTUNREACH))
                                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                        "WSARecvFrom: Windows error code: %d, isc result %d",
                                        Error, isc_result);
                        send_recvdone_abort(sock, isc_result);
                        break;
                }
        } else {
                /*
                 * The recv() finished immediately, but we will still get
                 * a completion event.  Rather than duplicate code, let
                 * that thread handle sending the data along its way.
                 */
                sock->pending_iocp++;
                sock->pending_recv++;
                sock->in_recovery_cnt = 0;
        }

        socket_log(__LINE__, sock, NULL, IOEVENT,
                   isc_msgcat, ISC_MSGSET_SOCKET,
                   ISC_MSG_DOIORECV,
                   "queue_io_request: fd %d result %d error %d",
                   sock->fd, Result, Error);

        CONSISTENT(sock);

        if (need_recovering)
                recover_receive_request(sock, &lpo);
}

/*
 * (placeholder) Hard recovery, doing nothing useful today
 * (other than to avoid unlimited recursion).
 */
static void
hard_recover_receive_request(isc_socket_t *sock)
{
        UNEXPECTED_ERROR(__FILE__, __LINE__,
                         "can't recover fd %d sock %p",
                         sock->fd, sock);
        send_recvdone_abort(sock, ISC_R_UNEXPECTED);
}

/*
 * Recovery from a Windows 2008 Server bug
 * (WSARecvFrom() getting an ERROR_HOST_UNREACHABLE).
 * Free the overlapped pointer and requeue a receive request.
 */
static void
recover_receive_request(isc_socket_t *sock, void **lplpo)
{
        if (*lplpo != NULL)
                HeapFree(hHeapHandle, 0, *lplpo);
        *lplpo = NULL;

        /* limit recursion to 20 */
        if (sock->in_recovery_cnt++ < 20)
                queue_receive_request(sock);
        else
                hard_recover_receive_request(sock);
}

static void
manager_log(isc_socketmgr_t *sockmgr, isc_logcategory_t *category,
            isc_logmodule_t *module, int level, const char *fmt, ...)
{
        char msgbuf[2048];
        va_list ap;

        if (!isc_log_wouldlog(isc_lctx, level))
                return;

        va_start(ap, fmt);
        vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
        va_end(ap);

        isc_log_write(isc_lctx, category, module, level,
                      "sockmgr %p: %s", sockmgr, msgbuf);
}

static void
socket_log(int lineno, isc_socket_t *sock, isc_sockaddr_t *address,
           isc_logcategory_t *category, isc_logmodule_t *module, int level,
           isc_msgcat_t *msgcat, int msgset, int message,
           const char *fmt, ...)
{
        char msgbuf[2048];
        char peerbuf[256];
        va_list ap;


        if (!isc_log_wouldlog(isc_lctx, level))
                return;

        va_start(ap, fmt);
        vsnprintf(msgbuf, sizeof(msgbuf), fmt, ap);
        va_end(ap);

        if (address == NULL) {
                isc_log_iwrite(isc_lctx, category, module, level,
                               msgcat, msgset, message,
                               "socket %p line %d: %s", sock, lineno, msgbuf);
        } else {
                isc_sockaddr_format(address, peerbuf, sizeof(peerbuf));
                isc_log_iwrite(isc_lctx, category, module, level,
                               msgcat, msgset, message,
                                   "socket %p line %d peer %s: %s", sock, lineno,
                                   peerbuf, msgbuf);
        }

}

/*
 * Make an fd SOCKET non-blocking.
 */
static isc_result_t
make_nonblock(SOCKET fd) {
        int ret;
        unsigned long flags = 1;
        char strbuf[ISC_STRERRORSIZE];

        /* Set the socket to non-blocking */
        ret = ioctlsocket(fd, FIONBIO, &flags);

        if (ret == -1) {
                isc__strerror(errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "ioctlsocket(%d, FIOBIO, %d): %s",
                                 fd, flags, strbuf);

                return (ISC_R_UNEXPECTED);
        }

        return (ISC_R_SUCCESS);
}

/*
 * Windows 2000 systems incorrectly cause UDP sockets using WSARecvFrom
 * to not work correctly, returning a WSACONNRESET error when a WSASendTo
 * fails with an "ICMP port unreachable" response and preventing the
 * socket from using the WSARecvFrom in subsequent operations.
 * The function below fixes this, but requires that Windows 2000
 * Service Pack 2 or later be installed on the system.  NT 4.0
 * systems are not affected by this and work correctly.
 * See Microsoft Knowledge Base Article Q263823 for details of this.
 */
isc_result_t
connection_reset_fix(SOCKET fd) {
        DWORD dwBytesReturned = 0;
        BOOL  bNewBehavior = FALSE;
        DWORD status;

        if (isc_win32os_majorversion() < 5)
                return (ISC_R_SUCCESS); /*  NT 4.0 has no problem */

        /* disable bad behavior using IOCTL: SIO_UDP_CONNRESET */
        status = WSAIoctl(fd, SIO_UDP_CONNRESET, &bNewBehavior,
                          sizeof(bNewBehavior), NULL, 0,
                          &dwBytesReturned, NULL, NULL);
        if (status != SOCKET_ERROR)
                return (ISC_R_SUCCESS);
        else {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "WSAIoctl(SIO_UDP_CONNRESET, oldBehaviour) %s",
                                 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                                ISC_MSG_FAILED, "failed"));
                return (ISC_R_UNEXPECTED);
        }
}

/*
 * Construct an iov array and attach it to the msghdr passed in.  This is
 * the SEND constructor, which will use the used region of the buffer
 * (if using a buffer list) or will use the internal region (if a single
 * buffer I/O is requested).
 *
 * Nothing can be NULL, and the done event must list at least one buffer
 * on the buffer linked list for this function to be meaningful.
 */
static void
build_msghdr_send(isc_socket_t *sock, isc_socketevent_t *dev,
                  struct msghdr *msg, char *cmsg, WSABUF *iov,
                  IoCompletionInfo  *lpo)
{
        unsigned int iovcount;
        isc_buffer_t *buffer;
        buflist_t  *cpbuffer;
        isc_region_t used;
        size_t write_count;
        size_t skip_count;

        memset(msg, 0, sizeof(*msg));

        memcpy(&msg->to_addr, &dev->address.type, dev->address.length);
        msg->to_addr_len = dev->address.length;

        buffer = ISC_LIST_HEAD(dev->bufferlist);
        write_count = 0;
        iovcount = 0;

        /*
         * Single buffer I/O?  Skip what we've done so far in this region.
         */
        if (buffer == NULL) {
                write_count = dev->region.length - dev->n;
                cpbuffer = HeapAlloc(hHeapHandle, HEAP_ZERO_MEMORY, sizeof(buflist_t));
                RUNTIME_CHECK(cpbuffer != NULL);
                cpbuffer->buf = HeapAlloc(hHeapHandle, HEAP_ZERO_MEMORY, write_count);
                RUNTIME_CHECK(cpbuffer->buf != NULL);

                socket_log(__LINE__, sock, NULL, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
                   "alloc_buffer %p %d %p %d", cpbuffer, sizeof(buflist_t),
                   cpbuffer->buf, write_count);

                memcpy(cpbuffer->buf,(dev->region.base + dev->n), write_count);
                cpbuffer->buflen = write_count;
                ISC_LIST_ENQUEUE(lpo->bufferlist, cpbuffer, link);
                iov[0].buf = cpbuffer->buf;
                iov[0].len = write_count;
                iovcount = 1;

                goto config;
        }

        /*
         * Multibuffer I/O.
         * Skip the data in the buffer list that we have already written.
         */
        skip_count = dev->n;
        while (buffer != NULL) {
                REQUIRE(ISC_BUFFER_VALID(buffer));
                if (skip_count < isc_buffer_usedlength(buffer))
                        break;
                skip_count -= isc_buffer_usedlength(buffer);
                buffer = ISC_LIST_NEXT(buffer, link);
        }

        while (buffer != NULL) {
                INSIST(iovcount < MAXSCATTERGATHER_SEND);

                isc_buffer_usedregion(buffer, &used);

                if (used.length > 0) {
                        int uselen = used.length - skip_count;
                        cpbuffer = HeapAlloc(hHeapHandle, HEAP_ZERO_MEMORY, sizeof(buflist_t));
                        RUNTIME_CHECK(cpbuffer != NULL);
                        cpbuffer->buf = HeapAlloc(hHeapHandle, HEAP_ZERO_MEMORY, uselen);
                        RUNTIME_CHECK(cpbuffer->buf != NULL);

                        socket_log(__LINE__, sock, NULL, TRACE,
                           isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
                           "alloc_buffer %p %d %p %d", cpbuffer, sizeof(buflist_t),
                           cpbuffer->buf, write_count);

                        memcpy(cpbuffer->buf,(used.base + skip_count), uselen);
                        cpbuffer->buflen = uselen;
                        iov[iovcount].buf = cpbuffer->buf;
                        iov[iovcount].len = used.length - skip_count;
                        write_count += uselen;
                        skip_count = 0;
                        iovcount++;
                }
                buffer = ISC_LIST_NEXT(buffer, link);
        }

        INSIST(skip_count == 0);

 config:
        msg->msg_iov = iov;
        msg->msg_iovlen = iovcount;
        msg->msg_totallen = write_count;
}

static void
set_dev_address(isc_sockaddr_t *address, isc_socket_t *sock,
                isc_socketevent_t *dev)
{
        if (sock->type == isc_sockettype_udp) {
                if (address != NULL)
                        dev->address = *address;
                else
                        dev->address = sock->address;
        } else if (sock->type == isc_sockettype_tcp) {
                INSIST(address == NULL);
                dev->address = sock->address;
        }
}

static void
destroy_socketevent(isc_event_t *event) {
        isc_socketevent_t *ev = (isc_socketevent_t *)event;

        INSIST(ISC_LIST_EMPTY(ev->bufferlist));

        (ev->destroy)(event);
}

static isc_socketevent_t *
allocate_socketevent(isc_socket_t *sock, isc_eventtype_t eventtype,
                     isc_taskaction_t action, const void *arg)
{
        isc_socketevent_t *ev;

        ev = (isc_socketevent_t *)isc_event_allocate(sock->manager->mctx,
                                                     sock, eventtype,
                                                     action, arg,
                                                     sizeof(*ev));
        if (ev == NULL)
                return (NULL);

        ev->result = ISC_R_IOERROR; // XXXMLG temporary change to detect failure to set
        ISC_LINK_INIT(ev, ev_link);
        ISC_LIST_INIT(ev->bufferlist);
        ev->region.base = NULL;
        ev->n = 0;
        ev->offset = 0;
        ev->attributes = 0;
        ev->destroy = ev->ev_destroy;
        ev->ev_destroy = destroy_socketevent;

        return (ev);
}

#if defined(ISC_SOCKET_DEBUG)
static void
dump_msg(struct msghdr *msg, isc_socket_t *sock) {
        unsigned int i;

        printf("MSGHDR %p, Socket #: %u\n", msg, sock->fd);
        printf("\tname %p, namelen %d\n", msg->msg_name, msg->msg_namelen);
        printf("\tiov %p, iovlen %d\n", msg->msg_iov, msg->msg_iovlen);
        for (i = 0; i < (unsigned int)msg->msg_iovlen; i++)
                printf("\t\t%d\tbase %p, len %d\n", i,
                       msg->msg_iov[i].buf,
                       msg->msg_iov[i].len);
}
#endif

/*
 * map the error code
 */
int
map_socket_error(isc_socket_t *sock, int windows_errno, int *isc_errno,
                 char *errorstring, size_t bufsize) {

        int doreturn;
        switch (windows_errno) {
        case WSAECONNREFUSED:
                *isc_errno = ISC_R_CONNREFUSED;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAENETUNREACH:
        case ERROR_NETWORK_UNREACHABLE:
                *isc_errno = ISC_R_NETUNREACH;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case ERROR_PORT_UNREACHABLE:
        case ERROR_HOST_UNREACHABLE:
        case WSAEHOSTUNREACH:
                *isc_errno = ISC_R_HOSTUNREACH;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAENETDOWN:
                *isc_errno = ISC_R_NETDOWN;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAEHOSTDOWN:
                *isc_errno = ISC_R_HOSTDOWN;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAEACCES:
                *isc_errno = ISC_R_NOPERM;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAECONNRESET:
        case WSAENETRESET:
        case WSAECONNABORTED:
        case WSAEDISCON:
                *isc_errno = ISC_R_CONNECTIONRESET;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case WSAENOTCONN:
                *isc_errno = ISC_R_NOTCONNECTED;
                if (sock->connected)
                        doreturn = DOIO_HARD;
                else
                        doreturn = DOIO_SOFT;
                break;
        case ERROR_OPERATION_ABORTED:
        case ERROR_CONNECTION_ABORTED:
        case ERROR_REQUEST_ABORTED:
                *isc_errno = ISC_R_CONNECTIONRESET;
                doreturn = DOIO_HARD;
                break;
        case WSAENOBUFS:
                *isc_errno = ISC_R_NORESOURCES;
                doreturn = DOIO_HARD;
                break;
        case WSAEAFNOSUPPORT:
                *isc_errno = ISC_R_FAMILYNOSUPPORT;
                doreturn = DOIO_HARD;
                break;
        case WSAEADDRNOTAVAIL:
                *isc_errno = ISC_R_ADDRNOTAVAIL;
                doreturn = DOIO_HARD;
                break;
        case WSAEDESTADDRREQ:
                *isc_errno = ISC_R_BADADDRESSFORM;
                doreturn = DOIO_HARD;
                break;
        case ERROR_NETNAME_DELETED:
                *isc_errno = ISC_R_NETDOWN;
                doreturn = DOIO_HARD;
                break;
        default:
                *isc_errno = ISC_R_IOERROR;
                doreturn = DOIO_HARD;
                break;
        }
        if (doreturn == DOIO_HARD) {
                isc__strerror(windows_errno, errorstring, bufsize);
        }
        return (doreturn);
}

static void
fill_recv(isc_socket_t *sock, isc_socketevent_t *dev) {
        isc_region_t r;
        int copylen;
        isc_buffer_t *buffer;

        INSIST(dev->n < dev->minimum);
        INSIST(sock->recvbuf.remaining > 0);
        INSIST(sock->pending_recv == 0);

        if (sock->type == isc_sockettype_udp) {
                dev->address.length = sock->recvbuf.from_addr_len;
                memcpy(&dev->address.type, &sock->recvbuf.from_addr,
                    sock->recvbuf.from_addr_len);
                if (isc_sockaddr_getport(&dev->address) == 0) {
                        if (isc_log_wouldlog(isc_lctx, IOEVENT_LEVEL)) {
                                socket_log(__LINE__, sock, &dev->address, IOEVENT,
                                           isc_msgcat, ISC_MSGSET_SOCKET,
                                           ISC_MSG_ZEROPORT,
                                           "dropping source port zero packet");
                        }
                        sock->recvbuf.remaining = 0;
                        return;
                }
        } else if (sock->type == isc_sockettype_tcp) {
                dev->address = sock->address;
        }

        /*
         * Run through the list of buffers we were given, and find the
         * first one with space.  Once it is found, loop through, filling
         * the buffers as much as possible.
         */
        buffer = ISC_LIST_HEAD(dev->bufferlist);
        if (buffer != NULL) { // Multi-buffer receive
                while (buffer != NULL && sock->recvbuf.remaining > 0) {
                        REQUIRE(ISC_BUFFER_VALID(buffer));
                        if (isc_buffer_availablelength(buffer) > 0) {
                                isc_buffer_availableregion(buffer, &r);
                                copylen = min(r.length, sock->recvbuf.remaining);
                                memcpy(r.base, sock->recvbuf.consume_position, copylen);
                                sock->recvbuf.consume_position += copylen;
                                sock->recvbuf.remaining -= copylen;
                                isc_buffer_add(buffer, copylen);
                                dev->n += copylen;
                        }
                        buffer = ISC_LIST_NEXT(buffer, link);
                }
        } else { // Single-buffer receive
                copylen = min(dev->region.length - dev->n, sock->recvbuf.remaining);
                memcpy(dev->region.base + dev->n, sock->recvbuf.consume_position, copylen);
                sock->recvbuf.consume_position += copylen;
                sock->recvbuf.remaining -= copylen;
                dev->n += copylen;
        }

        /*
         * UDP receives are all-consuming.  That is, if we have 4k worth of
         * data in our receive buffer, and the caller only gave us
         * 1k of space, we will toss the remaining 3k of data.  TCP
         * will keep the extra data around and use it for later requests.
         */
        if (sock->type == isc_sockettype_udp)
                sock->recvbuf.remaining = 0;
}

/*
 * Copy out as much data from the internal buffer to done events.
 * As each done event is filled, send it along its way.
 */
static void
completeio_recv(isc_socket_t *sock)
{
        isc_socketevent_t *dev;

        /*
         * If we are in the process of filling our buffer, we cannot
         * touch it yet, so don't.
         */
        if (sock->pending_recv > 0)
                return;

        while (sock->recvbuf.remaining > 0 && !ISC_LIST_EMPTY(sock->recv_list)) {
                dev = ISC_LIST_HEAD(sock->recv_list);

                /*
                 * See if we have sufficient data in our receive buffer
                 * to handle this.  If we do, copy out the data.
                 */
                fill_recv(sock, dev);

                /*
                 * Did we satisfy it?
                 */
                if (dev->n >= dev->minimum) {
                        dev->result = ISC_R_SUCCESS;
                        send_recvdone_event(sock, &dev);
                }
        }
}

/*
 * Returns:
 *      DOIO_SUCCESS    The operation succeeded.  dev->result contains
 *                      ISC_R_SUCCESS.
 *
 *      DOIO_HARD       A hard or unexpected I/O error was encountered.
 *                      dev->result contains the appropriate error.
 *
 *      DOIO_SOFT       A soft I/O error was encountered.  No senddone
 *                      event was sent.  The operation should be retried.
 *
 *      No other return values are possible.
 */
static int
completeio_send(isc_socket_t *sock, isc_socketevent_t *dev,
                struct msghdr *messagehdr, int cc, int send_errno)
{
        char addrbuf[ISC_SOCKADDR_FORMATSIZE];
        char strbuf[ISC_STRERRORSIZE];

        if (send_errno != 0) {
                if (SOFT_ERROR(send_errno))
                        return (DOIO_SOFT);

                return (map_socket_error(sock, send_errno, &dev->result,
                        strbuf, sizeof(strbuf)));

                /*
                 * The other error types depend on whether or not the
                 * socket is UDP or TCP.  If it is UDP, some errors
                 * that we expect to be fatal under TCP are merely
                 * annoying, and are really soft errors.
                 *
                 * However, these soft errors are still returned as
                 * a status.
                 */
                isc_sockaddr_format(&dev->address, addrbuf, sizeof(addrbuf));
                isc__strerror(send_errno, strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__, "completeio_send: %s: %s",
                                 addrbuf, strbuf);
                dev->result = isc__errno2result(send_errno);
                return (DOIO_HARD);
        }

        /*
         * If we write less than we expected, update counters, poke.
         */
        dev->n += cc;
        if (cc != messagehdr->msg_totallen)
                return (DOIO_SOFT);

        /*
         * Exactly what we wanted to write.  We're done with this
         * entry.  Post its completion event.
         */
        dev->result = ISC_R_SUCCESS;
        return (DOIO_SUCCESS);
}

static int
startio_send(isc_socket_t *sock, isc_socketevent_t *dev, int *nbytes,
             int *send_errno)
{
        char *cmsg = NULL;
        char strbuf[ISC_STRERRORSIZE];
        IoCompletionInfo *lpo;
        int status;
        struct msghdr *msghdr;

        lpo = (IoCompletionInfo *)HeapAlloc(hHeapHandle,
                                            HEAP_ZERO_MEMORY,
                                            sizeof(IoCompletionInfo));
        RUNTIME_CHECK(lpo != NULL);
        lpo->request_type = SOCKET_SEND;
        lpo->dev = dev;
        msghdr = &lpo->messagehdr;
        memset(msghdr, 0, sizeof(struct msghdr));
        ISC_LIST_INIT(lpo->bufferlist);

        build_msghdr_send(sock, dev, msghdr, cmsg, sock->iov, lpo);

        *nbytes = internal_sendmsg(sock, lpo, msghdr, 0, send_errno);

        if (*nbytes < 0) {
                /*
                 * I/O has been initiated
                 * completion will be through the completion port
                 */
                if (PENDING_ERROR(*send_errno)) {
                        status = DOIO_PENDING;
                        goto done;
                }

                if (SOFT_ERROR(*send_errno)) {
                        status = DOIO_SOFT;
                        goto done;
                }

                /*
                 * If we got this far then something is wrong
                 */
                if (isc_log_wouldlog(isc_lctx, IOEVENT_LEVEL)) {
                        isc__strerror(*send_errno, strbuf, sizeof(strbuf));
                        socket_log(__LINE__, sock, NULL, IOEVENT,
                                   isc_msgcat, ISC_MSGSET_SOCKET,
                                   ISC_MSG_INTERNALSEND,
                                   "startio_send: internal_sendmsg(%d) %d "
                                   "bytes, err %d/%s",
                                   sock->fd, *nbytes, *send_errno, strbuf);
                }
                status = DOIO_HARD;
                goto done;
        }
        dev->result = ISC_R_SUCCESS;
        status = DOIO_SOFT;
 done:
        _set_state(sock, SOCK_DATA);
        return (status);
}

static isc_result_t
allocate_socket(isc_socketmgr_t *manager, isc_sockettype_t type,
                isc_socket_t **socketp) {
        isc_socket_t *sock;
        isc_result_t result;

        sock = isc_mem_get(manager->mctx, sizeof(*sock));

        if (sock == NULL)
                return (ISC_R_NOMEMORY);

        sock->magic = 0;
        sock->references = 0;

        sock->manager = manager;
        sock->type = type;
        sock->fd = INVALID_SOCKET;

        ISC_LINK_INIT(sock, link);

        /*
         * set up list of readers and writers to be initially empty
         */
        ISC_LIST_INIT(sock->recv_list);
        ISC_LIST_INIT(sock->send_list);
        ISC_LIST_INIT(sock->accept_list);
        sock->connect_ev = NULL;
        sock->pending_accept = 0;
        sock->pending_recv = 0;
        sock->pending_send = 0;
        sock->pending_iocp = 0;
        sock->listener = 0;
        sock->connected = 0;
        sock->pending_connect = 0;
        sock->bound = 0;
        sock->in_recovery_cnt = 0;
        memset(sock->name, 0, sizeof(sock->name));      // zero the name field
        _set_state(sock, SOCK_INITIALIZED);

        sock->recvbuf.len = 65536;
        sock->recvbuf.consume_position = sock->recvbuf.base;
        sock->recvbuf.remaining = 0;
        sock->recvbuf.base = isc_mem_get(manager->mctx, sock->recvbuf.len); // max buffer size
        if (sock->recvbuf.base == NULL) {
                sock->magic = 0;
                goto error;
        }

        /*
         * initialize the lock
         */
        result = isc_mutex_init(&sock->lock);
        if (result != ISC_R_SUCCESS) {
                sock->magic = 0;
                isc_mem_put(manager->mctx, sock->recvbuf.base, sock->recvbuf.len);
                sock->recvbuf.base = NULL;
                goto error;
        }

        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                   "allocated");

        sock->magic = SOCKET_MAGIC;
        *socketp = sock;

        return (ISC_R_SUCCESS);

 error:
        isc_mem_put(manager->mctx, sock, sizeof(*sock));

        return (result);
}

/*
 * Verify that the socket state is consistent.
 */
static void
consistent(isc_socket_t *sock) {

        isc_socketevent_t *dev;
        isc_socket_newconnev_t *nev;
        unsigned int count;
        char *crash_reason;
        isc_boolean_t crash = ISC_FALSE;

        REQUIRE(sock->pending_iocp == sock->pending_recv + sock->pending_send
                + sock->pending_accept + sock->pending_connect);

        dev = ISC_LIST_HEAD(sock->send_list);
        count = 0;
        while (dev != NULL) {
                count++;
                dev = ISC_LIST_NEXT(dev, ev_link);
        }
        if (count > sock->pending_send) {
                crash = ISC_TRUE;
                crash_reason = "send_list > sock->pending_send";
        }

        nev = ISC_LIST_HEAD(sock->accept_list);
        count = 0;
        while (nev != NULL) {
                count++;
                nev = ISC_LIST_NEXT(nev, ev_link);
        }
        if (count > sock->pending_accept) {
                crash = ISC_TRUE;
                crash_reason = "send_list > sock->pending_send";
        }

        if (crash) {
                socket_log(__LINE__, sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
                           ISC_MSG_DESTROYING, "SOCKET INCONSISTENT: %s",
                           crash_reason);
                sock_dump(sock);
                INSIST(crash == ISC_FALSE);
        }
}

/*
 * Maybe free the socket.
 *
 * This function will verify tht the socket is no longer in use in any way,
 * either internally or externally.  This is the only place where this
 * check is to be made; if some bit of code believes that IT is done with
 * the socket (e.g., some reference counter reaches zero), it should call
 * this function.
 *
 * When calling this function, the socket must be locked, and the manager
 * must be unlocked.
 *
 * When this function returns, *socketp will be NULL.  No tricks to try
 * to hold on to this pointer are allowed.
 */
static void
maybe_free_socket(isc_socket_t **socketp, int lineno) {
        isc_socket_t *sock = *socketp;
        *socketp = NULL;

        INSIST(VALID_SOCKET(sock));
        CONSISTENT(sock);

        if (sock->pending_iocp > 0
            || sock->pending_recv > 0
            || sock->pending_send > 0
            || sock->pending_accept > 0
            || sock->references > 0
            || sock->pending_connect == 1
            || !ISC_LIST_EMPTY(sock->recv_list)
            || !ISC_LIST_EMPTY(sock->send_list)
            || !ISC_LIST_EMPTY(sock->accept_list)
            || sock->fd != INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return;
        }
        UNLOCK(&sock->lock);

        free_socket(&sock, lineno);
}

void
free_socket(isc_socket_t **sockp, int lineno) {
        isc_socketmgr_t *manager;
        isc_socket_t *sock = *sockp;
        *sockp = NULL;

        manager = sock->manager;

        /*
         * Seems we can free the socket after all.
         */
        manager = sock->manager;
        socket_log(__LINE__, sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
                   ISC_MSG_DESTROYING, "freeing socket line %d fd %d lock %p semaphore %p",
                   lineno, sock->fd, &sock->lock, sock->lock.LockSemaphore);

        sock->magic = 0;
        DESTROYLOCK(&sock->lock);

        if (sock->recvbuf.base != NULL)
                isc_mem_put(manager->mctx, sock->recvbuf.base, sock->recvbuf.len);

        LOCK(&manager->lock);
        if (ISC_LINK_LINKED(sock, link))
                ISC_LIST_UNLINK(manager->socklist, sock, link);
        isc_mem_put(manager->mctx, sock, sizeof(*sock));

        if (ISC_LIST_EMPTY(manager->socklist))
                SIGNAL(&manager->shutdown_ok);
        UNLOCK(&manager->lock);
}

/*
 * Create a new 'type' socket managed by 'manager'.  Events
 * will be posted to 'task' and when dispatched 'action' will be
 * called with 'arg' as the arg value.  The new socket is returned
 * in 'socketp'.
 */
isc_result_t
isc__socket_create(isc_socketmgr_t *manager, int pf, isc_sockettype_t type,
                  isc_socket_t **socketp) {
        isc_socket_t *sock = NULL;
        isc_result_t result;
#if defined(USE_CMSG)
        int on = 1;
#endif
#if defined(SO_RCVBUF)
        ISC_SOCKADDR_LEN_T optlen;
        int size;
#endif
        int socket_errno;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_MANAGER(manager));
        REQUIRE(socketp != NULL && *socketp == NULL);
        REQUIRE(type != isc_sockettype_fdwatch);

        result = allocate_socket(manager, type, &sock);
        if (result != ISC_R_SUCCESS)
                return (result);

        sock->pf = pf;
        switch (type) {
        case isc_sockettype_udp:
                sock->fd = socket(pf, SOCK_DGRAM, IPPROTO_UDP);
                if (sock->fd != INVALID_SOCKET) {
                        result = connection_reset_fix(sock->fd);
                        if (result != ISC_R_SUCCESS) {
                                socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                                        "closed %d %d %d con_reset_fix_failed",
                                        sock->pending_recv, sock->pending_send,
                                        sock->references);
                                closesocket(sock->fd);
                                _set_state(sock, SOCK_CLOSED);
                                sock->fd = INVALID_SOCKET;
                                free_socket(&sock, __LINE__);
                                return (result);
                        }
                }
                break;
        case isc_sockettype_tcp:
                sock->fd = socket(pf, SOCK_STREAM, IPPROTO_TCP);
                break;
        }

        if (sock->fd == INVALID_SOCKET) {
                socket_errno = WSAGetLastError();
                free_socket(&sock, __LINE__);

                switch (socket_errno) {
                case WSAEMFILE:
                case WSAENOBUFS:
                        return (ISC_R_NORESOURCES);

                case WSAEPROTONOSUPPORT:
                case WSAEPFNOSUPPORT:
                case WSAEAFNOSUPPORT:
                        return (ISC_R_FAMILYNOSUPPORT);

                default:
                        isc__strerror(socket_errno, strbuf, sizeof(strbuf));
                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "socket() %s: %s",
                                         isc_msgcat_get(isc_msgcat,
                                                        ISC_MSGSET_GENERAL,
                                                        ISC_MSG_FAILED,
                                                        "failed"),
                                         strbuf);
                        return (ISC_R_UNEXPECTED);
                }
        }

        result = make_nonblock(sock->fd);
        if (result != ISC_R_SUCCESS) {
                socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                        "closed %d %d %d make_nonblock_failed",
                        sock->pending_recv, sock->pending_send,
                        sock->references);
                closesocket(sock->fd);
                sock->fd = INVALID_SOCKET;
                free_socket(&sock, __LINE__);
                return (result);
        }


#if defined(USE_CMSG) || defined(SO_RCVBUF)
        if (type == isc_sockettype_udp) {

#if defined(USE_CMSG)
#if defined(ISC_PLATFORM_HAVEIPV6)
#ifdef IPV6_RECVPKTINFO
                /* 2292bis */
                if ((pf == AF_INET6)
                    && (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
                                   (char *)&on, sizeof(on)) < 0)) {
                        isc__strerror(WSAGetLastError(), strbuf, sizeof(strbuf));
                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "setsockopt(%d, IPV6_RECVPKTINFO) "
                                         "%s: %s", sock->fd,
                                         isc_msgcat_get(isc_msgcat,
                                                        ISC_MSGSET_GENERAL,
                                                        ISC_MSG_FAILED,
                                                        "failed"),
                                         strbuf);
                }
#else
                /* 2292 */
                if ((pf == AF_INET6)
                    && (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_PKTINFO,
                                   (char *)&on, sizeof(on)) < 0)) {
                        isc__strerror(WSAGetLastError(), strbuf, sizeof(strbuf));
                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "setsockopt(%d, IPV6_PKTINFO) %s: %s",
                                         sock->fd,
                                         isc_msgcat_get(isc_msgcat,
                                                        ISC_MSGSET_GENERAL,
                                                        ISC_MSG_FAILED,
                                                        "failed"),
                                         strbuf);
                }
#endif /* IPV6_RECVPKTINFO */
#ifdef IPV6_USE_MIN_MTU /*2292bis, not too common yet*/
                /* use minimum MTU */
                if (pf == AF_INET6) {
                        (void)setsockopt(sock->fd, IPPROTO_IPV6,
                                         IPV6_USE_MIN_MTU,
                                         (char *)&on, sizeof(on));
                }
#endif
#endif /* ISC_PLATFORM_HAVEIPV6 */
#endif /* defined(USE_CMSG) */

#if defined(SO_RCVBUF)
               optlen = sizeof(size);
               if (getsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
                              (char *)&size, &optlen) >= 0 &&
                    size < RCVBUFSIZE) {
                       size = RCVBUFSIZE;
                       (void)setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
                                        (char *)&size, sizeof(size));
               }
#endif

        }
#endif /* defined(USE_CMSG) || defined(SO_RCVBUF) */

        _set_state(sock, SOCK_OPEN);
        sock->references = 1;
        *socketp = sock;

        iocompletionport_update(sock);

        /*
         * Note we don't have to lock the socket like we normally would because
         * there are no external references to it yet.
         */
        LOCK(&manager->lock);
        ISC_LIST_APPEND(manager->socklist, sock, link);
        InterlockedIncrement(&manager->totalSockets);
        UNLOCK(&manager->lock);

        socket_log(__LINE__, sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
                   ISC_MSG_CREATED, "created %u type %u", sock->fd, type);

        return (ISC_R_SUCCESS);
}

isc_result_t
isc_socket_open(isc_socket_t *sock) {
        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(sock->type != isc_sockettype_fdwatch);

        return (ISC_R_NOTIMPLEMENTED);
}

/*
 * Attach to a socket.  Caller must explicitly detach when it is done.
 */
void
isc__socket_attach(isc_socket_t *sock, isc_socket_t **socketp) {
        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(socketp != NULL && *socketp == NULL);

        LOCK(&sock->lock);
        CONSISTENT(sock);
        sock->references++;
        UNLOCK(&sock->lock);

        *socketp = sock;
}

/*
 * Dereference a socket.  If this is the last reference to it, clean things
 * up by destroying the socket.
 */
void
isc__socket_detach(isc_socket_t **socketp) {
        isc_socket_t *sock;
        isc_boolean_t kill_socket = ISC_FALSE;

        REQUIRE(socketp != NULL);
        sock = *socketp;
        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(sock->type != isc_sockettype_fdwatch);

        LOCK(&sock->lock);
        CONSISTENT(sock);
        REQUIRE(sock->references > 0);
        sock->references--;

        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                "detach_socket %d %d %d",
                sock->pending_recv, sock->pending_send,
                sock->references);

        if (sock->references == 0 && sock->fd != INVALID_SOCKET) {
                closesocket(sock->fd);
                sock->fd = INVALID_SOCKET;
                _set_state(sock, SOCK_CLOSED);
        }

        maybe_free_socket(&sock, __LINE__);

        *socketp = NULL;
}

isc_result_t
isc_socket_close(isc_socket_t *sock) {
        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(sock->type != isc_sockettype_fdwatch);

        return (ISC_R_NOTIMPLEMENTED);
}

/*
 * Dequeue an item off the given socket's read queue, set the result code
 * in the done event to the one provided, and send it to the task it was
 * destined for.
 *
 * If the event to be sent is on a list, remove it before sending.  If
 * asked to, send and detach from the task as well.
 *
 * Caller must have the socket locked if the event is attached to the socket.
 */
static void
send_recvdone_event(isc_socket_t *sock, isc_socketevent_t **dev) {
        isc_task_t *task;

        task = (*dev)->ev_sender;
        (*dev)->ev_sender = sock;

        if (ISC_LINK_LINKED(*dev, ev_link))
                ISC_LIST_DEQUEUE(sock->recv_list, *dev, ev_link);

        if (((*dev)->attributes & ISC_SOCKEVENTATTR_ATTACHED)
            == ISC_SOCKEVENTATTR_ATTACHED)
                isc_task_sendanddetach(&task, (isc_event_t **)dev);
        else
                isc_task_send(task, (isc_event_t **)dev);

        CONSISTENT(sock);
}

/*
 * See comments for send_recvdone_event() above.
 */
static void
send_senddone_event(isc_socket_t *sock, isc_socketevent_t **dev) {
        isc_task_t *task;

        INSIST(dev != NULL && *dev != NULL);

        task = (*dev)->ev_sender;
        (*dev)->ev_sender = sock;

        if (ISC_LINK_LINKED(*dev, ev_link))
                ISC_LIST_DEQUEUE(sock->send_list, *dev, ev_link);

        if (((*dev)->attributes & ISC_SOCKEVENTATTR_ATTACHED)
            == ISC_SOCKEVENTATTR_ATTACHED)
                isc_task_sendanddetach(&task, (isc_event_t **)dev);
        else
                isc_task_send(task, (isc_event_t **)dev);

        CONSISTENT(sock);
}

/*
 * See comments for send_recvdone_event() above.
 */
static void
send_acceptdone_event(isc_socket_t *sock, isc_socket_newconnev_t **adev) {
        isc_task_t *task;

        INSIST(adev != NULL && *adev != NULL);

        task = (*adev)->ev_sender;
        (*adev)->ev_sender = sock;

        if (ISC_LINK_LINKED(*adev, ev_link))
                ISC_LIST_DEQUEUE(sock->accept_list, *adev, ev_link);

        isc_task_sendanddetach(&task, (isc_event_t **)adev);

        CONSISTENT(sock);
}

/*
 * See comments for send_recvdone_event() above.
 */
static void
send_connectdone_event(isc_socket_t *sock, isc_socket_connev_t **cdev) {
        isc_task_t *task;

        INSIST(cdev != NULL && *cdev != NULL);

        task = (*cdev)->ev_sender;
        (*cdev)->ev_sender = sock;

        sock->connect_ev = NULL;

        isc_task_sendanddetach(&task, (isc_event_t **)cdev);

        CONSISTENT(sock);
}

/*
 * On entry to this function, the event delivered is the internal
 * readable event, and the first item on the accept_list should be
 * the done event we want to send.  If the list is empty, this is a no-op,
 * so just close the new connection, unlock, and return.
 *
 * Note the socket is locked before entering here
 */
static void
internal_accept(isc_socket_t *sock, IoCompletionInfo *lpo, int accept_errno) {
        isc_socket_newconnev_t *adev;
        isc_result_t result = ISC_R_SUCCESS;
        isc_socket_t *nsock;
        struct sockaddr *localaddr;
        int localaddr_len = sizeof(*localaddr);
        struct sockaddr *remoteaddr;
        int remoteaddr_len = sizeof(*remoteaddr);

        INSIST(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        socket_log(__LINE__, sock, NULL, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
                   "internal_accept called");

        INSIST(sock->listener);

        INSIST(sock->pending_iocp > 0);
        sock->pending_iocp--;
        INSIST(sock->pending_accept > 0);
        sock->pending_accept--;

        adev = lpo->adev;

        /*
         * If the event is no longer in the list we can just return.
         */
        if (!acceptdone_is_active(sock, adev))
                goto done;

        nsock = adev->newsocket;

        /*
         * Pull off the done event.
         */
        ISC_LIST_UNLINK(sock->accept_list, adev, ev_link);

        /*
         * Extract the addresses from the socket, copy them into the structure,
         * and return the new socket.
         */
        ISCGetAcceptExSockaddrs(lpo->acceptbuffer, 0,
                sizeof(SOCKADDR_STORAGE) + 16, sizeof(SOCKADDR_STORAGE) + 16,
                (LPSOCKADDR *)&localaddr, &localaddr_len,
                (LPSOCKADDR *)&remoteaddr, &remoteaddr_len);
        memcpy(&adev->address.type, remoteaddr, remoteaddr_len);
        adev->address.length = remoteaddr_len;
        nsock->address = adev->address;
        nsock->pf = adev->address.type.sa.sa_family;

        socket_log(__LINE__, nsock, &nsock->address, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
                   "internal_accept parent %p", sock);

        result = make_nonblock(adev->newsocket->fd);
        INSIST(result == ISC_R_SUCCESS);

        INSIST(setsockopt(nsock->fd, SOL_SOCKET, SO_UPDATE_ACCEPT_CONTEXT,
                          (char *)&sock->fd, sizeof(sock->fd)) == 0);

        /*
         * Hook it up into the manager.
         */
        nsock->bound = 1;
        nsock->connected = 1;
        _set_state(nsock, SOCK_OPEN);

        LOCK(&nsock->manager->lock);
        ISC_LIST_APPEND(nsock->manager->socklist, nsock, link);
        InterlockedIncrement(&nsock->manager->totalSockets);
        UNLOCK(&nsock->manager->lock);

        socket_log(__LINE__, sock, &nsock->address, CREATION,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTEDCXN,
                   "accepted_connection new_socket %p fd %d",
                   nsock, nsock->fd);

        adev->result = result;
        send_acceptdone_event(sock, &adev);

done:
        CONSISTENT(sock);
        UNLOCK(&sock->lock);

        HeapFree(hHeapHandle, 0, lpo->acceptbuffer);
        lpo->acceptbuffer = NULL;
}

/*
 * Called when a socket with a pending connect() finishes.
 * Note that the socket is locked before entering.
 */
static void
internal_connect(isc_socket_t *sock, IoCompletionInfo *lpo, int connect_errno) {
        isc_socket_connev_t *cdev;
        char strbuf[ISC_STRERRORSIZE];

        INSIST(VALID_SOCKET(sock));

        LOCK(&sock->lock);

        INSIST(sock->pending_iocp > 0);
        sock->pending_iocp--;
        INSIST(sock->pending_connect == 1);
        sock->pending_connect = 0;

        /*
         * Has this event been canceled?
         */
        cdev = lpo->cdev;
        if (!connectdone_is_active(sock, cdev)) {
                sock->pending_connect = 0;
                if (sock->fd != INVALID_SOCKET) {
                        closesocket(sock->fd);
                        sock->fd = INVALID_SOCKET;
                        _set_state(sock, SOCK_CLOSED);
                }
                CONSISTENT(sock);
                UNLOCK(&sock->lock);
                return;
        }

        /*
         * Check possible Windows network event error status here.
         */
        if (connect_errno != 0) {
                /*
                 * If the error is SOFT, just try again on this
                 * fd and pretend nothing strange happened.
                 */
                if (SOFT_ERROR(connect_errno) ||
                    connect_errno == WSAEINPROGRESS) {
                        sock->pending_connect = 1;
                        CONSISTENT(sock);
                        UNLOCK(&sock->lock);
                        return;
                }

                /*
                 * Translate other errors into ISC_R_* flavors.
                 */
                switch (connect_errno) {
#define ERROR_MATCH(a, b) case a: cdev->result = b; break;
                        ERROR_MATCH(WSAEACCES, ISC_R_NOPERM);
                        ERROR_MATCH(WSAEADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
                        ERROR_MATCH(WSAEAFNOSUPPORT, ISC_R_ADDRNOTAVAIL);
                        ERROR_MATCH(WSAECONNREFUSED, ISC_R_CONNREFUSED);
                        ERROR_MATCH(WSAEHOSTUNREACH, ISC_R_HOSTUNREACH);
                        ERROR_MATCH(WSAEHOSTDOWN, ISC_R_HOSTDOWN);
                        ERROR_MATCH(WSAENETUNREACH, ISC_R_NETUNREACH);
                        ERROR_MATCH(WSAENETDOWN, ISC_R_NETDOWN);
                        ERROR_MATCH(WSAENOBUFS, ISC_R_NORESOURCES);
                        ERROR_MATCH(WSAECONNRESET, ISC_R_CONNECTIONRESET);
                        ERROR_MATCH(WSAECONNABORTED, ISC_R_CONNECTIONRESET);
                        ERROR_MATCH(WSAETIMEDOUT, ISC_R_TIMEDOUT);
#undef ERROR_MATCH
                default:
                        cdev->result = ISC_R_UNEXPECTED;
                        isc__strerror(connect_errno, strbuf, sizeof(strbuf));
                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                         "internal_connect: connect() %s",
                                         strbuf);
                }
        } else {
                INSIST(setsockopt(sock->fd, SOL_SOCKET,
                                  SO_UPDATE_CONNECT_CONTEXT, NULL, 0) == 0);
                cdev->result = ISC_R_SUCCESS;
                sock->connected = 1;
                socket_log(__LINE__, sock, &sock->address, IOEVENT,
                           isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTEDCXN,
                           "internal_connect: success");
        }

        send_connectdone_event(sock, &cdev);

        UNLOCK(&sock->lock);
}

/*
 * Loop through the socket, returning ISC_R_EOF for each done event pending.
 */
static void
send_recvdone_abort(isc_socket_t *sock, isc_result_t result) {
        isc_socketevent_t *dev;

        while (!ISC_LIST_EMPTY(sock->recv_list)) {
                dev = ISC_LIST_HEAD(sock->recv_list);
                dev->result = result;
                send_recvdone_event(sock, &dev);
        }
}

/*
 * Take the data we received in our private buffer, and if any recv() calls on
 * our list are satisfied, send the corresponding done event.
 *
 * If we need more data (there are still items on the recv_list after we consume all
 * our data) then arrange for another system recv() call to fill our buffers.
 */
static void
internal_recv(isc_socket_t *sock, int nbytes)
{
        INSIST(VALID_SOCKET(sock));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        socket_log(__LINE__, sock, NULL, IOEVENT,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALRECV,
                   "internal_recv: %d bytes received", nbytes);

        /*
         * If we got here, the I/O operation succeeded.  However, we might still have removed this
         * event from our notification list (or never placed it on it due to immediate completion.)
         * Handle the reference counting here, and handle the cancellation event just after.
         */
        INSIST(sock->pending_iocp > 0);
        sock->pending_iocp--;
        INSIST(sock->pending_recv > 0);
        sock->pending_recv--;

        /*
         * The only way we could have gotten here is that our I/O has successfully completed.
         * Update our pointers, and move on.  The only odd case here is that we might not
         * have received enough data on a TCP stream to satisfy the minimum requirements.  If
         * this is the case, we will re-issue the recv() call for what we need.
         *
         * We do check for a recv() of 0 bytes on a TCP stream.  This means the remote end
         * has closed.
         */
        if (nbytes == 0 && sock->type == isc_sockettype_tcp) {
                send_recvdone_abort(sock, ISC_R_EOF);
                maybe_free_socket(&sock, __LINE__);
                return;
        }
        sock->recvbuf.remaining = nbytes;
        sock->recvbuf.consume_position = sock->recvbuf.base;
        completeio_recv(sock);

        /*
         * If there are more receivers waiting for data, queue another receive
         * here.
         */
        queue_receive_request(sock);

        /*
         * Unlock and/or destroy if we are the last thing this socket has left to do.
         */
        maybe_free_socket(&sock, __LINE__);
}

static void
internal_send(isc_socket_t *sock, isc_socketevent_t *dev,
              struct msghdr *messagehdr, int nbytes, int send_errno, IoCompletionInfo *lpo)
{
        buflist_t *buffer;

        /*
         * Find out what socket this is and lock it.
         */
        INSIST(VALID_SOCKET(sock));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        socket_log(__LINE__, sock, NULL, IOEVENT,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALSEND,
                   "internal_send: task got socket event %p", dev);

        buffer = ISC_LIST_HEAD(lpo->bufferlist);
        while (buffer != NULL) {
                ISC_LIST_DEQUEUE(lpo->bufferlist, buffer, link);

                socket_log(__LINE__, sock, NULL, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
                   "free_buffer %p %p", buffer, buffer->buf);

                HeapFree(hHeapHandle, 0, buffer->buf);
                HeapFree(hHeapHandle, 0, buffer);
                buffer = ISC_LIST_HEAD(lpo->bufferlist);
        }

        INSIST(sock->pending_iocp > 0);
        sock->pending_iocp--;
        INSIST(sock->pending_send > 0);
        sock->pending_send--;

        /* If the event is no longer in the list we can just return */
        if (!senddone_is_active(sock, dev))
                goto done;

        /*
         * Set the error code and send things on its way.
         */
        switch (completeio_send(sock, dev, messagehdr, nbytes, send_errno)) {
        case DOIO_SOFT:
                break;
        case DOIO_HARD:
        case DOIO_SUCCESS:
                send_senddone_event(sock, &dev);
                break;
        }

 done:
        maybe_free_socket(&sock, __LINE__);
}

/*
 * These return if the done event passed in is on the list (or for connect, is
 * the one we're waiting for.  Using these ensures we will not double-send an
 * event.
 */
static isc_boolean_t
senddone_is_active(isc_socket_t *sock, isc_socketevent_t *dev)
{
        isc_socketevent_t *ldev;

        ldev = ISC_LIST_HEAD(sock->send_list);
        while (ldev != NULL && ldev != dev)
                ldev = ISC_LIST_NEXT(ldev, ev_link);

        return (ldev == NULL ? ISC_FALSE : ISC_TRUE);
}

static isc_boolean_t
acceptdone_is_active(isc_socket_t *sock, isc_socket_newconnev_t *dev)
{
        isc_socket_newconnev_t *ldev;

        ldev = ISC_LIST_HEAD(sock->accept_list);
        while (ldev != NULL && ldev != dev)
                ldev = ISC_LIST_NEXT(ldev, ev_link);

        return (ldev == NULL ? ISC_FALSE : ISC_TRUE);
}

static isc_boolean_t
connectdone_is_active(isc_socket_t *sock, isc_socket_connev_t *dev)
{
        return (sock->connect_ev == dev ? ISC_TRUE : ISC_FALSE);
}

/*
 * This is the I/O Completion Port Worker Function. It loops forever
 * waiting for I/O to complete and then forwards them for further
 * processing. There are a number of these in separate threads.
 */
static isc_threadresult_t WINAPI
SocketIoThread(LPVOID ThreadContext) {
        isc_socketmgr_t *manager = ThreadContext;
        BOOL bSuccess = FALSE;
        DWORD nbytes;
        IoCompletionInfo *lpo = NULL;
        isc_socket_t *sock = NULL;
        int request;
        struct msghdr *messagehdr = NULL;
        int errval;
        char strbuf[ISC_STRERRORSIZE];
        int errstatus;

        REQUIRE(VALID_MANAGER(manager));

        /*
         * Set the thread priority high enough so I/O will
         * preempt normal recv packet processing, but not
         * higher than the timer sync thread.
         */
        if (!SetThreadPriority(GetCurrentThread(),
                               THREAD_PRIORITY_ABOVE_NORMAL)) {
                errval = GetLastError();
                isc__strerror(errval, strbuf, sizeof(strbuf));
                FATAL_ERROR(__FILE__, __LINE__,
                                isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                ISC_MSG_FAILED,
                                "Can't set thread priority: %s"),
                                strbuf);
        }

        /*
         * Loop forever waiting on I/O Completions and then processing them
         */
        while (TRUE) {
                bSuccess = GetQueuedCompletionStatus(manager->hIoCompletionPort,
                                                     &nbytes, (LPDWORD)&sock,
                                                     (LPWSAOVERLAPPED *)&lpo,
                                                     INFINITE);
                if (lpo == NULL) /* Received request to exit */
                        break;

                REQUIRE(VALID_SOCKET(sock));

                request = lpo->request_type;

                errstatus = 0;
                if (!bSuccess) {
                        isc_result_t isc_result;

                        /*
                         * Did the I/O operation complete?
                         */
                        errstatus = GetLastError();
                        isc_result = isc__errno2resultx(errstatus, __FILE__, __LINE__);

                        LOCK(&sock->lock);
                        CONSISTENT(sock);
                        switch (request) {
                        case SOCKET_RECV:
                                INSIST(sock->pending_iocp > 0);
                                sock->pending_iocp--;
                                INSIST(sock->pending_recv > 0);
                                sock->pending_recv--;
                                if ((sock->type == isc_sockettype_udp) &&
                                    (errstatus == ERROR_HOST_UNREACHABLE)) {
                                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                                         "SOCKET_RECV ERROR_HOST_UNREACHABLE: trying to recover");
                                        recover_receive_request(sock, &lpo);
                                        break;
                                }
                                if ((sock->type == isc_sockettype_udp) &&
                                    (errstatus == WSAENETRESET)) {
                                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                                         "SOCKET_RECV WSAENETRESET: trying to recover");
                                        recover_receive_request(sock, &lpo);
                                        break;
                                }
                                if ((sock->type == isc_sockettype_udp) &&
                                    (errstatus == WSAECONNRESET)) {
                                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                                         "SOCKET_RECV WSAECONNRESET: trying to recover");
                                        recover_receive_request(sock, &lpo);
                                        break;
                                }
                                send_recvdone_abort(sock, isc_result);
                                if ((isc_result == ISC_R_UNEXPECTED) ||
                                    ((isc_result == ISC_R_CONNECTIONRESET) &&
                                     (errstatus != ERROR_OPERATION_ABORTED)) ||
                                    (isc_result == ISC_R_HOSTUNREACH)) {
                                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                                "SOCKET_RECV: Windows error code: %d, returning ISC error %d",
                                                errstatus, isc_result);
                                }
                                break;

                        case SOCKET_SEND:
                                INSIST(sock->pending_iocp > 0);
                                sock->pending_iocp--;
                                INSIST(sock->pending_send > 0);
                                sock->pending_send--;
                                if (senddone_is_active(sock, lpo->dev)) {
                                        lpo->dev->result = isc_result;
                                        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                                                "canceled_send");
                                        send_senddone_event(sock, &lpo->dev);
                                }
                                break;

                        case SOCKET_ACCEPT:
                                INSIST(sock->pending_iocp > 0);
                                sock->pending_iocp--;
                                INSIST(sock->pending_accept > 0);
                                sock->pending_accept--;
                                if (acceptdone_is_active(sock, lpo->adev)) {
                                        closesocket(lpo->adev->newsocket->fd);
                                        lpo->adev->newsocket->fd = INVALID_SOCKET;
                                        lpo->adev->newsocket->references--;
                                        free_socket(&lpo->adev->newsocket, __LINE__);
                                        lpo->adev->result = isc_result;
                                        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                                                "canceled_accept");
                                        send_acceptdone_event(sock, &lpo->adev);
                                }
                                break;

                        case SOCKET_CONNECT:
                                INSIST(sock->pending_iocp > 0);
                                sock->pending_iocp--;
                                INSIST(sock->pending_connect == 1);
                                sock->pending_connect = 0;
                                if (connectdone_is_active(sock, lpo->cdev)) {
                                        lpo->cdev->result = isc_result;
                                        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                                                "canceled_connect");
                                        send_connectdone_event(sock, &lpo->cdev);
                                }
                                break;
                        }
                        maybe_free_socket(&sock, __LINE__);

                        if (lpo != NULL)
                                HeapFree(hHeapHandle, 0, lpo);
                        continue;
                }

                messagehdr = &lpo->messagehdr;

                switch (request) {
                case SOCKET_RECV:
                        internal_recv(sock, nbytes);
                        break;
                case SOCKET_SEND:
                        internal_send(sock, lpo->dev, messagehdr, nbytes, errstatus, lpo);
                        break;
                case SOCKET_ACCEPT:
                        internal_accept(sock, lpo, errstatus);
                        break;
                case SOCKET_CONNECT:
                        internal_connect(sock, lpo, errstatus);
                        break;
                }

                if (lpo != NULL)
                        HeapFree(hHeapHandle, 0, lpo);
        }

        /*
         * Exit Completion Port Thread
         */
        manager_log(manager, TRACE,
                    isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                   ISC_MSG_EXITING, "SocketIoThread exiting"));
        return ((isc_threadresult_t)0);
}

/*
 * Create a new socket manager.
 */
isc_result_t
isc__socketmgr_create(isc_mem_t *mctx, isc_socketmgr_t **managerp) {
        return (isc_socketmgr_create2(mctx, managerp, 0));
}

isc_result_t
isc__socketmgr_create2(isc_mem_t *mctx, isc_socketmgr_t **managerp,
                       unsigned int maxsocks)
{
        isc_socketmgr_t *manager;
        isc_result_t result;

        REQUIRE(managerp != NULL && *managerp == NULL);

        if (maxsocks != 0)
                return (ISC_R_NOTIMPLEMENTED);

        manager = isc_mem_get(mctx, sizeof(*manager));
        if (manager == NULL)
                return (ISC_R_NOMEMORY);

        InitSockets();

        manager->magic = SOCKET_MANAGER_MAGIC;
        manager->mctx = NULL;
        manager->stats = NULL;
        ISC_LIST_INIT(manager->socklist);
        result = isc_mutex_init(&manager->lock);
        if (result != ISC_R_SUCCESS) {
                isc_mem_put(mctx, manager, sizeof(*manager));
                return (result);
        }
        if (isc_condition_init(&manager->shutdown_ok) != ISC_R_SUCCESS) {
                DESTROYLOCK(&manager->lock);
                isc_mem_put(mctx, manager, sizeof(*manager));
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "isc_condition_init() %s",
                                 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                                ISC_MSG_FAILED, "failed"));
                return (ISC_R_UNEXPECTED);
        }

        isc_mem_attach(mctx, &manager->mctx);

        iocompletionport_init(manager); /* Create the Completion Ports */

        manager->bShutdown = ISC_FALSE;
        manager->totalSockets = 0;
        manager->iocp_total = 0;

        *managerp = manager;

        return (ISC_R_SUCCESS);
}

isc_result_t
isc__socketmgr_getmaxsockets(isc_socketmgr_t *manager, unsigned int *nsockp) {
        REQUIRE(VALID_MANAGER(manager));
        REQUIRE(nsockp != NULL);

        return (ISC_R_NOTIMPLEMENTED);
}

void
isc__socketmgr_setstats(isc_socketmgr_t *manager, isc_stats_t *stats) {
        REQUIRE(VALID_MANAGER(manager));
        REQUIRE(ISC_LIST_EMPTY(manager->socklist));
        REQUIRE(manager->stats == NULL);
        REQUIRE(isc_stats_ncounters(stats) == isc_sockstatscounter_max);

        isc_stats_attach(stats, &manager->stats);
}

void
isc__socketmgr_destroy(isc_socketmgr_t **managerp) {
        isc_socketmgr_t *manager;
        int i;
        isc_mem_t *mctx;

        /*
         * Destroy a socket manager.
         */

        REQUIRE(managerp != NULL);
        manager = *managerp;
        REQUIRE(VALID_MANAGER(manager));

        LOCK(&manager->lock);

        /*
         * Wait for all sockets to be destroyed.
         */
        while (!ISC_LIST_EMPTY(manager->socklist)) {
                manager_log(manager, CREATION,
                            isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
                                           ISC_MSG_SOCKETSREMAIN,
                                           "sockets exist"));
                WAIT(&manager->shutdown_ok, &manager->lock);
        }

        UNLOCK(&manager->lock);

        /*
         * Here, we need to had some wait code for the completion port
         * thread.
         */
        signal_iocompletionport_exit(manager);
        manager->bShutdown = ISC_TRUE;

        /*
         * Wait for threads to exit.
         */
        for (i = 0; i < manager->maxIOCPThreads; i++) {
                if (isc_thread_join((isc_thread_t) manager->hIOCPThreads[i],
                        NULL) != ISC_R_SUCCESS)
                        UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "isc_thread_join() for Completion Port %s",
                                 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                                ISC_MSG_FAILED, "failed"));
        }
        /*
         * Clean up.
         */

        CloseHandle(manager->hIoCompletionPort);

        (void)isc_condition_destroy(&manager->shutdown_ok);

        DESTROYLOCK(&manager->lock);
        if (manager->stats != NULL)
                isc_stats_detach(&manager->stats);
        manager->magic = 0;
        mctx= manager->mctx;
        isc_mem_put(mctx, manager, sizeof(*manager));

        isc_mem_detach(&mctx);

        *managerp = NULL;
}

static void
queue_receive_event(isc_socket_t *sock, isc_task_t *task, isc_socketevent_t *dev)
{
        isc_task_t *ntask = NULL;

        isc_task_attach(task, &ntask);
        dev->attributes |= ISC_SOCKEVENTATTR_ATTACHED;

        /*
         * Enqueue the request.
         */
        INSIST(!ISC_LINK_LINKED(dev, ev_link));
        ISC_LIST_ENQUEUE(sock->recv_list, dev, ev_link);

        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                   "queue_receive_event: event %p -> task %p",
                   dev, ntask);
}

/*
 * Check the pending receive queue, and if we have data pending, give it to this
 * caller.  If we have none, queue an I/O request.  If this caller is not the first
 * on the list, then we will just queue this event and return.
 *
 * Caller must have the socket locked.
 */
static isc_result_t
socket_recv(isc_socket_t *sock, isc_socketevent_t *dev, isc_task_t *task,
            unsigned int flags)
{
        int cc = 0;
        isc_task_t *ntask = NULL;
        isc_result_t result = ISC_R_SUCCESS;
        int recv_errno = 0;

        dev->ev_sender = task;

        if (sock->fd == INVALID_SOCKET)
                return (ISC_R_EOF);

        /*
         * Queue our event on the list of things to do.  Call our function to
         * attempt to fill buffers as much as possible, and return done events.
         * We are going to lie about our handling of the ISC_SOCKFLAG_IMMEDIATE
         * here and tell our caller that we could not satisfy it immediately.
         */
        queue_receive_event(sock, task, dev);
        if ((flags & ISC_SOCKFLAG_IMMEDIATE) != 0)
                result = ISC_R_INPROGRESS;

        completeio_recv(sock);

        /*
         * If there are more receivers waiting for data, queue another receive
         * here.  If the
         */
        queue_receive_request(sock);

        return (result);
}

isc_result_t
isc__socket_recvv(isc_socket_t *sock, isc_bufferlist_t *buflist,
                 unsigned int minimum, isc_task_t *task,
                 isc_taskaction_t action, const void *arg)
{
        isc_socketevent_t *dev;
        isc_socketmgr_t *manager;
        unsigned int iocount;
        isc_buffer_t *buffer;
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * Make sure that the socket is not closed.  XXXMLG change error here?
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        REQUIRE(buflist != NULL);
        REQUIRE(!ISC_LIST_EMPTY(*buflist));
        REQUIRE(task != NULL);
        REQUIRE(action != NULL);

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));

        iocount = isc_bufferlist_availablecount(buflist);
        REQUIRE(iocount > 0);

        INSIST(sock->bound);

        dev = allocate_socketevent(sock, ISC_SOCKEVENT_RECVDONE, action, arg);
        if (dev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }

        /*
         * UDP sockets are always partial read
         */
        if (sock->type == isc_sockettype_udp)
                dev->minimum = 1;
        else {
                if (minimum == 0)
                        dev->minimum = iocount;
                else
                        dev->minimum = minimum;
        }

        /*
         * Move each buffer from the passed in list to our internal one.
         */
        buffer = ISC_LIST_HEAD(*buflist);
        while (buffer != NULL) {
                ISC_LIST_DEQUEUE(*buflist, buffer, link);
                ISC_LIST_ENQUEUE(dev->bufferlist, buffer, link);
                buffer = ISC_LIST_HEAD(*buflist);
        }

        ret = socket_recv(sock, dev, task, 0);

        UNLOCK(&sock->lock);
        return (ret);
}

isc_result_t
isc__socket_recv(isc_socket_t *sock, isc_region_t *region,
                 unsigned int minimum, isc_task_t *task,
                 isc_taskaction_t action, const void *arg)
{
        isc_socketevent_t *dev;
        isc_socketmgr_t *manager;
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }
        REQUIRE(action != NULL);

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));

        INSIST(sock->bound);

        dev = allocate_socketevent(sock, ISC_SOCKEVENT_RECVDONE, action, arg);
        if (dev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }

        ret = isc_socket_recv2(sock, region, minimum, task, dev, 0);
        UNLOCK(&sock->lock);
        return (ret);
}

isc_result_t
isc__socket_recv2(isc_socket_t *sock, isc_region_t *region,
                  unsigned int minimum, isc_task_t *task,
                  isc_socketevent_t *event, unsigned int flags)
{
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        event->result = ISC_R_UNEXPECTED;
        event->ev_sender = sock;
        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        ISC_LIST_INIT(event->bufferlist);
        event->region = *region;
        event->n = 0;
        event->offset = 0;
        event->attributes = 0;

        /*
         * UDP sockets are always partial read.
         */
        if (sock->type == isc_sockettype_udp)
                event->minimum = 1;
        else {
                if (minimum == 0)
                        event->minimum = region->length;
                else
                        event->minimum = minimum;
        }

        ret = socket_recv(sock, event, task, flags);
        UNLOCK(&sock->lock);
        return (ret);
}

/*
 * Caller must have the socket locked.
 */
static isc_result_t
socket_send(isc_socket_t *sock, isc_socketevent_t *dev, isc_task_t *task,
            isc_sockaddr_t *address, struct in6_pktinfo *pktinfo,
            unsigned int flags)
{
        int io_state;
        int send_errno = 0;
        int cc = 0;
        isc_task_t *ntask = NULL;
        isc_result_t result = ISC_R_SUCCESS;

        dev->ev_sender = task;

        set_dev_address(address, sock, dev);
        if (pktinfo != NULL) {
                socket_log(__LINE__, sock, NULL, TRACE, isc_msgcat, ISC_MSGSET_SOCKET,
                           ISC_MSG_PKTINFOPROVIDED,
                           "pktinfo structure provided, ifindex %u (set to 0)",
                           pktinfo->ipi6_ifindex);

                dev->attributes |= ISC_SOCKEVENTATTR_PKTINFO;
                dev->pktinfo = *pktinfo;
                /*
                 * Set the pktinfo index to 0 here, to let the kernel decide
                 * what interface it should send on.
                 */
                dev->pktinfo.ipi6_ifindex = 0;
        }

        io_state = startio_send(sock, dev, &cc, &send_errno);
        switch (io_state) {
        case DOIO_PENDING:      /* I/O started. Nothing more to do */
        case DOIO_SOFT:
                /*
                 * We couldn't send all or part of the request right now, so
                 * queue it unless ISC_SOCKFLAG_NORETRY is set.
                 */
                if ((flags & ISC_SOCKFLAG_NORETRY) == 0) {
                        isc_task_attach(task, &ntask);
                        dev->attributes |= ISC_SOCKEVENTATTR_ATTACHED;

                        /*
                         * Enqueue the request.
                         */
                        INSIST(!ISC_LINK_LINKED(dev, ev_link));
                        ISC_LIST_ENQUEUE(sock->send_list, dev, ev_link);

                        socket_log(__LINE__, sock, NULL, EVENT, NULL, 0, 0,
                                   "socket_send: event %p -> task %p",
                                   dev, ntask);

                        if ((flags & ISC_SOCKFLAG_IMMEDIATE) != 0)
                                result = ISC_R_INPROGRESS;
                        break;
                }

        case DOIO_SUCCESS:
                break;
        }

        return (result);
}

isc_result_t
isc__socket_send(isc_socket_t *sock, isc_region_t *region,
                 isc_task_t *task, isc_taskaction_t action, const void *arg)
{
        /*
         * REQUIRE() checking is performed in isc_socket_sendto().
         */
        return (isc_socket_sendto(sock, region, task, action, arg, NULL,
                                  NULL));
}

isc_result_t
isc__socket_sendto(isc_socket_t *sock, isc_region_t *region,
                   isc_task_t *task, isc_taskaction_t action, const void *arg,
                   isc_sockaddr_t *address, struct in6_pktinfo *pktinfo)
{
        isc_socketevent_t *dev;
        isc_socketmgr_t *manager;
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(sock->type != isc_sockettype_fdwatch);

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }
        REQUIRE(region != NULL);
        REQUIRE(task != NULL);
        REQUIRE(action != NULL);

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));

        INSIST(sock->bound);

        dev = allocate_socketevent(sock, ISC_SOCKEVENT_SENDDONE, action, arg);
        if (dev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }
        dev->region = *region;

        ret = socket_send(sock, dev, task, address, pktinfo, 0);
        UNLOCK(&sock->lock);
        return (ret);
}

isc_result_t
isc__socket_sendv(isc_socket_t *sock, isc_bufferlist_t *buflist,
                  isc_task_t *task, isc_taskaction_t action, const void *arg)
{
        return (isc_socket_sendtov(sock, buflist, task, action, arg, NULL,
                                   NULL));
}

isc_result_t
isc__socket_sendtov(isc_socket_t *sock, isc_bufferlist_t *buflist,
                    isc_task_t *task, isc_taskaction_t action, const void *arg,
                    isc_sockaddr_t *address, struct in6_pktinfo *pktinfo)
{
        isc_socketevent_t *dev;
        isc_socketmgr_t *manager;
        unsigned int iocount;
        isc_buffer_t *buffer;
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }
        REQUIRE(buflist != NULL);
        REQUIRE(!ISC_LIST_EMPTY(*buflist));
        REQUIRE(task != NULL);
        REQUIRE(action != NULL);

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));

        iocount = isc_bufferlist_usedcount(buflist);
        REQUIRE(iocount > 0);

        dev = allocate_socketevent(sock, ISC_SOCKEVENT_SENDDONE, action, arg);
        if (dev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }

        /*
         * Move each buffer from the passed in list to our internal one.
         */
        buffer = ISC_LIST_HEAD(*buflist);
        while (buffer != NULL) {
                ISC_LIST_DEQUEUE(*buflist, buffer, link);
                ISC_LIST_ENQUEUE(dev->bufferlist, buffer, link);
                buffer = ISC_LIST_HEAD(*buflist);
        }

        ret = socket_send(sock, dev, task, address, pktinfo, 0);
        UNLOCK(&sock->lock);
        return (ret);
}

isc_result_t
isc__socket_sendto2(isc_socket_t *sock, isc_region_t *region,
                    isc_task_t *task,
                    isc_sockaddr_t *address, struct in6_pktinfo *pktinfo,
                    isc_socketevent_t *event, unsigned int flags)
{
        isc_result_t ret;

        REQUIRE(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        REQUIRE((flags & ~(ISC_SOCKFLAG_IMMEDIATE|ISC_SOCKFLAG_NORETRY)) == 0);
        if ((flags & ISC_SOCKFLAG_NORETRY) != 0)
                REQUIRE(sock->type == isc_sockettype_udp);
        event->ev_sender = sock;
        event->result = ISC_R_UNEXPECTED;
        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }
        ISC_LIST_INIT(event->bufferlist);
        event->region = *region;
        event->n = 0;
        event->offset = 0;
        event->attributes = 0;

        ret = socket_send(sock, event, task, address, pktinfo, flags);
        UNLOCK(&sock->lock);
        return (ret);
}

isc_result_t
isc__socket_bind(isc_socket_t *sock, isc_sockaddr_t *sockaddr,
                 unsigned int options) {
        int bind_errno;
        char strbuf[ISC_STRERRORSIZE];
        int on = 1;

        REQUIRE(VALID_SOCKET(sock));
        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        INSIST(!sock->bound);

        if (sock->pf != sockaddr->type.sa.sa_family) {
                UNLOCK(&sock->lock);
                return (ISC_R_FAMILYMISMATCH);
        }
        /*
         * Only set SO_REUSEADDR when we want a specific port.
         */
        if ((options & ISC_SOCKET_REUSEADDRESS) != 0 &&
            isc_sockaddr_getport(sockaddr) != (in_port_t)0 &&
            setsockopt(sock->fd, SOL_SOCKET, SO_REUSEADDR, (char *)&on,
                       sizeof(on)) < 0) {
                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                 "setsockopt(%d) %s", sock->fd,
                                 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
                                                ISC_MSG_FAILED, "failed"));
                /* Press on... */
        }
        if (bind(sock->fd, &sockaddr->type.sa, sockaddr->length) < 0) {
                bind_errno = WSAGetLastError();
                UNLOCK(&sock->lock);
                switch (bind_errno) {
                case WSAEACCES:
                        return (ISC_R_NOPERM);
                case WSAEADDRNOTAVAIL:
                        return (ISC_R_ADDRNOTAVAIL);
                case WSAEADDRINUSE:
                        return (ISC_R_ADDRINUSE);
                case WSAEINVAL:
                        return (ISC_R_BOUND);
                default:
                        isc__strerror(bind_errno, strbuf, sizeof(strbuf));
                        UNEXPECTED_ERROR(__FILE__, __LINE__, "bind: %s",
                                         strbuf);
                        return (ISC_R_UNEXPECTED);
                }
        }

        socket_log(__LINE__, sock, sockaddr, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_BOUND, "bound");
        sock->bound = 1;

        UNLOCK(&sock->lock);
        return (ISC_R_SUCCESS);
}

isc_result_t
isc__socket_filter(isc_socket_t *sock, const char *filter) {
        UNUSED(sock);
        UNUSED(filter);

        REQUIRE(VALID_SOCKET(sock));
        return (ISC_R_NOTIMPLEMENTED);
}

/*
 * Set up to listen on a given socket.  We do this by creating an internal
 * event that will be dispatched when the socket has read activity.  The
 * watcher will send the internal event to the task when there is a new
 * connection.
 *
 * Unlike in read, we don't preallocate a done event here.  Every time there
 * is a new connection we'll have to allocate a new one anyway, so we might
 * as well keep things simple rather than having to track them.
 */
isc_result_t
isc__socket_listen(isc_socket_t *sock, unsigned int backlog) {
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_SOCKET(sock));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        REQUIRE(!sock->listener);
        REQUIRE(sock->bound);
        REQUIRE(sock->type == isc_sockettype_tcp);

        if (backlog == 0)
                backlog = SOMAXCONN;

        if (listen(sock->fd, (int)backlog) < 0) {
                UNLOCK(&sock->lock);
                isc__strerror(WSAGetLastError(), strbuf, sizeof(strbuf));

                UNEXPECTED_ERROR(__FILE__, __LINE__, "listen: %s", strbuf);

                return (ISC_R_UNEXPECTED);
        }

        socket_log(__LINE__, sock, NULL, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_BOUND, "listening");
        sock->listener = 1;
        _set_state(sock, SOCK_LISTEN);

        UNLOCK(&sock->lock);
        return (ISC_R_SUCCESS);
}

/*
 * This should try to do aggressive accept() XXXMLG
 */
isc_result_t
isc__socket_accept(isc_socket_t *sock,
                   isc_task_t *task, isc_taskaction_t action, const void *arg)
{
        isc_socket_newconnev_t *adev;
        isc_socketmgr_t *manager;
        isc_task_t *ntask = NULL;
        isc_socket_t *nsock;
        isc_result_t result;
        IoCompletionInfo *lpo;

        REQUIRE(VALID_SOCKET(sock));

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        REQUIRE(sock->listener);

        /*
         * Sender field is overloaded here with the task we will be sending
         * this event to.  Just before the actual event is delivered the
         * actual ev_sender will be touched up to be the socket.
         */
        adev = (isc_socket_newconnev_t *)
                isc_event_allocate(manager->mctx, task, ISC_SOCKEVENT_NEWCONN,
                                   action, arg, sizeof(*adev));
        if (adev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }
        ISC_LINK_INIT(adev, ev_link);

        result = allocate_socket(manager, sock->type, &nsock);
        if (result != ISC_R_SUCCESS) {
                isc_event_free((isc_event_t **)&adev);
                UNLOCK(&sock->lock);
                return (result);
        }

        /*
         * AcceptEx() requires we pass in a socket.
         */
        nsock->fd = socket(sock->pf, SOCK_STREAM, IPPROTO_TCP);
        if (nsock->fd == INVALID_SOCKET) {
                free_socket(&nsock, __LINE__);
                isc_event_free((isc_event_t **)&adev);
                UNLOCK(&sock->lock);
                return (ISC_R_FAILURE); // XXXMLG need real error message
        }

        /*
         * Attach to socket and to task.
         */
        isc_task_attach(task, &ntask);
        nsock->references++;

        adev->ev_sender = ntask;
        adev->newsocket = nsock;
        _set_state(nsock, SOCK_ACCEPT);

        /*
         * Queue io completion for an accept().
         */
        lpo = (IoCompletionInfo *)HeapAlloc(hHeapHandle,
                                            HEAP_ZERO_MEMORY,
                                            sizeof(IoCompletionInfo));
        RUNTIME_CHECK(lpo != NULL);
        lpo->acceptbuffer = (void *)HeapAlloc(hHeapHandle, HEAP_ZERO_MEMORY,
                (sizeof(SOCKADDR_STORAGE) + 16) * 2);
        RUNTIME_CHECK(lpo->acceptbuffer != NULL);

        lpo->adev = adev;
        lpo->request_type = SOCKET_ACCEPT;

        ISCAcceptEx(sock->fd,
                    nsock->fd,                          /* Accepted Socket */
                    lpo->acceptbuffer,                  /* Buffer for initial Recv */
                    0,                                  /* Length of Buffer */
                    sizeof(SOCKADDR_STORAGE) + 16,              /* Local address length + 16 */
                    sizeof(SOCKADDR_STORAGE) + 16,              /* Remote address lengh + 16 */
                    (LPDWORD)&lpo->received_bytes,      /* Bytes Recved */
                    (LPOVERLAPPED)lpo                   /* Overlapped structure */
                    );
        iocompletionport_update(nsock);

        socket_log(__LINE__, sock, NULL, TRACE,
                   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_BOUND,
                   "accepting for nsock %p fd %d", nsock, nsock->fd);

        /*
         * Enqueue the event
         */
        ISC_LIST_ENQUEUE(sock->accept_list, adev, ev_link);
        sock->pending_accept++;
        sock->pending_iocp++;

        UNLOCK(&sock->lock);
        return (ISC_R_SUCCESS);
}

isc_result_t
isc__socket_connect(isc_socket_t *sock, isc_sockaddr_t *addr,
                    isc_task_t *task, isc_taskaction_t action, const void *arg)
{
        char strbuf[ISC_STRERRORSIZE];
        isc_socket_connev_t *cdev;
        isc_task_t *ntask = NULL;
        isc_socketmgr_t *manager;
        IoCompletionInfo *lpo;
        int bind_errno;

        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(addr != NULL);
        REQUIRE(task != NULL);
        REQUIRE(action != NULL);

        manager = sock->manager;
        REQUIRE(VALID_MANAGER(manager));
        REQUIRE(addr != NULL);

        if (isc_sockaddr_ismulticast(addr))
                return (ISC_R_MULTICAST);

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        /*
         * Windows sockets won't connect unless the socket is bound.
         */
        if (!sock->bound) {
                isc_sockaddr_t any;

                isc_sockaddr_anyofpf(&any, isc_sockaddr_pf(addr));
                if (bind(sock->fd, &any.type.sa, any.length) < 0) {
                        bind_errno = WSAGetLastError();
                        UNLOCK(&sock->lock);
                        switch (bind_errno) {
                        case WSAEACCES:
                                return (ISC_R_NOPERM);
                        case WSAEADDRNOTAVAIL:
                                return (ISC_R_ADDRNOTAVAIL);
                        case WSAEADDRINUSE:
                                return (ISC_R_ADDRINUSE);
                        case WSAEINVAL:
                                return (ISC_R_BOUND);
                        default:
                                isc__strerror(bind_errno, strbuf,
                                              sizeof(strbuf));
                                UNEXPECTED_ERROR(__FILE__, __LINE__,
                                                 "bind: %s", strbuf);
                                return (ISC_R_UNEXPECTED);
                        }
                }
                sock->bound = 1;
        }

        REQUIRE(!sock->pending_connect);

        cdev = (isc_socket_connev_t *)isc_event_allocate(manager->mctx, sock,
                                                        ISC_SOCKEVENT_CONNECT,
                                                        action, arg,
                                                        sizeof(*cdev));
        if (cdev == NULL) {
                UNLOCK(&sock->lock);
                return (ISC_R_NOMEMORY);
        }
        ISC_LINK_INIT(cdev, ev_link);

        if (sock->type == isc_sockettype_tcp) {
                /*
                 * Queue io completion for an accept().
                 */
                lpo = (IoCompletionInfo *)HeapAlloc(hHeapHandle,
                                                    HEAP_ZERO_MEMORY,
                                                    sizeof(IoCompletionInfo));
                lpo->cdev = cdev;
                lpo->request_type = SOCKET_CONNECT;

                sock->address = *addr;
                ISCConnectEx(sock->fd, &addr->type.sa, addr->length,
                        NULL, 0, NULL, (LPOVERLAPPED)lpo);

                /*
                 * Attach to task.
                 */
                isc_task_attach(task, &ntask);
                cdev->ev_sender = ntask;

                sock->pending_connect = 1;
                _set_state(sock, SOCK_CONNECT);

                /*
                 * Enqueue the request.
                 */
                sock->connect_ev = cdev;
                sock->pending_iocp++;
        } else {
                WSAConnect(sock->fd, &addr->type.sa, addr->length, NULL, NULL, NULL, NULL);
                cdev->result = ISC_R_SUCCESS;
                isc_task_send(task, (isc_event_t **)&cdev);
        }
        CONSISTENT(sock);
        UNLOCK(&sock->lock);

        return (ISC_R_SUCCESS);
}

isc_result_t
isc__socket_getpeername(isc_socket_t *sock, isc_sockaddr_t *addressp) {
        isc_result_t result;

        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(addressp != NULL);

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        if (sock->connected) {
                *addressp = sock->address;
                result = ISC_R_SUCCESS;
        } else {
                result = ISC_R_NOTCONNECTED;
        }

        UNLOCK(&sock->lock);

        return (result);
}

isc_result_t
isc__socket_getsockname(isc_socket_t *sock, isc_sockaddr_t *addressp) {
        ISC_SOCKADDR_LEN_T len;
        isc_result_t result;
        char strbuf[ISC_STRERRORSIZE];

        REQUIRE(VALID_SOCKET(sock));
        REQUIRE(addressp != NULL);

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        if (!sock->bound) {
                result = ISC_R_NOTBOUND;
                goto out;
        }

        result = ISC_R_SUCCESS;

        len = sizeof(addressp->type);
        if (getsockname(sock->fd, &addressp->type.sa, (void *)&len) < 0) {
                isc__strerror(WSAGetLastError(), strbuf, sizeof(strbuf));
                UNEXPECTED_ERROR(__FILE__, __LINE__, "getsockname: %s",
                                 strbuf);
                result = ISC_R_UNEXPECTED;
                goto out;
        }
        addressp->length = (unsigned int)len;

 out:
        UNLOCK(&sock->lock);

        return (result);
}

/*
 * Run through the list of events on this socket, and cancel the ones
 * queued for task "task" of type "how".  "how" is a bitmask.
 */
void
isc__socket_cancel(isc_socket_t *sock, isc_task_t *task, unsigned int how) {

        REQUIRE(VALID_SOCKET(sock));

        /*
         * Quick exit if there is nothing to do.  Don't even bother locking
         * in this case.
         */
        if (how == 0)
                return;

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return;
        }

        /*
         * All of these do the same thing, more or less.
         * Each will:
         *      o If the internal event is marked as "posted" try to
         *        remove it from the task's queue.  If this fails, mark it
         *        as canceled instead, and let the task clean it up later.
         *      o For each I/O request for that task of that type, post
         *        its done event with status of "ISC_R_CANCELED".
         *      o Reset any state needed.
         */

        if ((how & ISC_SOCKCANCEL_RECV) == ISC_SOCKCANCEL_RECV) {
                isc_socketevent_t      *dev;
                isc_socketevent_t      *next;
                isc_task_t             *current_task;

                dev = ISC_LIST_HEAD(sock->recv_list);
                while (dev != NULL) {
                        current_task = dev->ev_sender;
                        next = ISC_LIST_NEXT(dev, ev_link);
                        if ((task == NULL) || (task == current_task)) {
                                dev->result = ISC_R_CANCELED;
                                send_recvdone_event(sock, &dev);
                        }
                        dev = next;
                }
        }
        how &= ~ISC_SOCKCANCEL_RECV;

        if ((how & ISC_SOCKCANCEL_SEND) == ISC_SOCKCANCEL_SEND) {
                isc_socketevent_t      *dev;
                isc_socketevent_t      *next;
                isc_task_t             *current_task;

                dev = ISC_LIST_HEAD(sock->send_list);

                while (dev != NULL) {
                        current_task = dev->ev_sender;
                        next = ISC_LIST_NEXT(dev, ev_link);
                        if ((task == NULL) || (task == current_task)) {
                                dev->result = ISC_R_CANCELED;
                                send_senddone_event(sock, &dev);
                        }
                        dev = next;
                }
        }
        how &= ~ISC_SOCKCANCEL_SEND;

        if (((how & ISC_SOCKCANCEL_ACCEPT) == ISC_SOCKCANCEL_ACCEPT)
            && !ISC_LIST_EMPTY(sock->accept_list)) {
                isc_socket_newconnev_t *dev;
                isc_socket_newconnev_t *next;
                isc_task_t             *current_task;

                dev = ISC_LIST_HEAD(sock->accept_list);
                while (dev != NULL) {
                        current_task = dev->ev_sender;
                        next = ISC_LIST_NEXT(dev, ev_link);

                        if ((task == NULL) || (task == current_task)) {

                                dev->newsocket->references--;
                                closesocket(dev->newsocket->fd);
                                dev->newsocket->fd = INVALID_SOCKET;
                                free_socket(&dev->newsocket, __LINE__);

                                dev->result = ISC_R_CANCELED;
                                send_acceptdone_event(sock, &dev);
                        }

                        dev = next;
                }
        }
        how &= ~ISC_SOCKCANCEL_ACCEPT;

        /*
         * Connecting is not a list.
         */
        if (((how & ISC_SOCKCANCEL_CONNECT) == ISC_SOCKCANCEL_CONNECT)
            && sock->connect_ev != NULL) {
                isc_socket_connev_t    *dev;
                isc_task_t             *current_task;

                INSIST(sock->pending_connect);

                dev = sock->connect_ev;
                current_task = dev->ev_sender;

                if ((task == NULL) || (task == current_task)) {
                        closesocket(sock->fd);
                        sock->fd = INVALID_SOCKET;
                        _set_state(sock, SOCK_CLOSED);

                        sock->connect_ev = NULL;
                        dev->result = ISC_R_CANCELED;
                        send_connectdone_event(sock, &dev);
                }
        }
        how &= ~ISC_SOCKCANCEL_CONNECT;

        maybe_free_socket(&sock, __LINE__);
}

isc_sockettype_t
isc__socket_gettype(isc_socket_t *sock) {
        isc_sockettype_t type;

        REQUIRE(VALID_SOCKET(sock));

        LOCK(&sock->lock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_R_CONNREFUSED);
        }

        type = sock->type;
        UNLOCK(&sock->lock);
        return (type);
}

isc_boolean_t
isc__socket_isbound(isc_socket_t *sock) {
        isc_boolean_t val;

        REQUIRE(VALID_SOCKET(sock));

        LOCK(&sock->lock);
        CONSISTENT(sock);

        /*
         * make sure that the socket's not closed
         */
        if (sock->fd == INVALID_SOCKET) {
                UNLOCK(&sock->lock);
                return (ISC_FALSE);
        }

        val = ((sock->bound) ? ISC_TRUE : ISC_FALSE);
        UNLOCK(&sock->lock);

        return (val);
}

void
isc__socket_ipv6only(isc_socket_t *sock, isc_boolean_t yes) {
#if defined(IPV6_V6ONLY)
        int onoff = yes ? 1 : 0;
#else
        UNUSED(yes);
#endif

        REQUIRE(VALID_SOCKET(sock));

#ifdef IPV6_V6ONLY
        if (sock->pf == AF_INET6) {
                (void)setsockopt(sock->fd, IPPROTO_IPV6, IPV6_V6ONLY,
                                 (char *)&onoff, sizeof(onoff));
        }
#endif
}

void
isc__socket_cleanunix(isc_sockaddr_t *addr, isc_boolean_t active) {
        UNUSED(addr);
        UNUSED(active);
}

isc_result_t
isc__socket_permunix(isc_sockaddr_t *addr, isc_uint32_t perm,
                     isc_uint32_t owner,        isc_uint32_t group)
{
        UNUSED(addr);
        UNUSED(perm);
        UNUSED(owner);
        UNUSED(group);
        return (ISC_R_NOTIMPLEMENTED);
}

void
isc__socket_setname(isc_socket_t *socket, const char *name, void *tag) {

        /*
         * Name 'socket'.
         */

        REQUIRE(VALID_SOCKET(socket));

        LOCK(&socket->lock);
        memset(socket->name, 0, sizeof(socket->name));
        strncpy(socket->name, name, sizeof(socket->name) - 1);
        socket->tag = tag;
        UNLOCK(&socket->lock);
}

const char *
isc__socket_getname(isc_socket_t *socket) {
        return (socket->name);
}

void *
isc__socket_gettag(isc_socket_t *socket) {
        return (socket->tag);
}

void
isc__socketmgr_setreserved(isc_socketmgr_t *manager, isc_uint32_t reserved) {
        UNUSED(manager);
        UNUSED(reserved);
}

void
isc___socketmgr_maxudp(isc_socketmgr_t *manager, int maxudp) {

        UNUSED(manager);
        UNUSED(maxudp);
}

#ifdef HAVE_LIBXML2

static const char *
_socktype(isc_sockettype_t type)
{
        if (type == isc_sockettype_udp)
                return ("udp");
        else if (type == isc_sockettype_tcp)
                return ("tcp");
        else if (type == isc_sockettype_unix)
                return ("unix");
        else if (type == isc_sockettype_fdwatch)
                return ("fdwatch");
        else
                return ("not-initialized");
}

void
isc_socketmgr_renderxml(isc_socketmgr_t *mgr, xmlTextWriterPtr writer)
{
        isc_socket_t *sock;
        char peerbuf[ISC_SOCKADDR_FORMATSIZE];
        isc_sockaddr_t addr;
        ISC_SOCKADDR_LEN_T len;

        LOCK(&mgr->lock);

#ifndef ISC_PLATFORM_USETHREADS
        xmlTextWriterStartElement(writer, ISC_XMLCHAR "references");
        xmlTextWriterWriteFormatString(writer, "%d", mgr->refs);
        xmlTextWriterEndElement(writer);
#endif

        xmlTextWriterStartElement(writer, ISC_XMLCHAR "sockets");
        sock = ISC_LIST_HEAD(mgr->socklist);
        while (sock != NULL) {
                LOCK(&sock->lock);
                xmlTextWriterStartElement(writer, ISC_XMLCHAR "socket");

                xmlTextWriterStartElement(writer, ISC_XMLCHAR "id");
                xmlTextWriterWriteFormatString(writer, "%p", sock);
                xmlTextWriterEndElement(writer);

                if (sock->name[0] != 0) {
                        xmlTextWriterStartElement(writer, ISC_XMLCHAR "name");
                        xmlTextWriterWriteFormatString(writer, "%s",
                                                       sock->name);
                        xmlTextWriterEndElement(writer); /* name */
                }

                xmlTextWriterStartElement(writer, ISC_XMLCHAR "references");
                xmlTextWriterWriteFormatString(writer, "%d", sock->references);
                xmlTextWriterEndElement(writer);

                xmlTextWriterWriteElement(writer, ISC_XMLCHAR "type",
                                          ISC_XMLCHAR _socktype(sock->type));

                if (sock->connected) {
                        isc_sockaddr_format(&sock->address, peerbuf,
                                            sizeof(peerbuf));
                        xmlTextWriterWriteElement(writer,
                                                  ISC_XMLCHAR "peer-address",
                                                  ISC_XMLCHAR peerbuf);
                }

                len = sizeof(addr);
                if (getsockname(sock->fd, &addr.type.sa, (void *)&len) == 0) {
                        isc_sockaddr_format(&addr, peerbuf, sizeof(peerbuf));
                        xmlTextWriterWriteElement(writer,
                                                  ISC_XMLCHAR "local-address",
                                                  ISC_XMLCHAR peerbuf);
                }

                xmlTextWriterStartElement(writer, ISC_XMLCHAR "states");
                if (sock->pending_recv)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                ISC_XMLCHAR "pending-receive");
                if (sock->pending_send)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                  ISC_XMLCHAR "pending-send");
                if (sock->pending_accept)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                 ISC_XMLCHAR "pending_accept");
                if (sock->listener)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                  ISC_XMLCHAR "listener");
                if (sock->connected)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                  ISC_XMLCHAR "connected");
                if (sock->pending_connect)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                  ISC_XMLCHAR "connecting");
                if (sock->bound)
                        xmlTextWriterWriteElement(writer, ISC_XMLCHAR "state",
                                                  ISC_XMLCHAR "bound");

                xmlTextWriterEndElement(writer); /* states */

                xmlTextWriterEndElement(writer); /* socket */

                UNLOCK(&sock->lock);
                sock = ISC_LIST_NEXT(sock, link);
        }
        xmlTextWriterEndElement(writer); /* sockets */

        UNLOCK(&mgr->lock);
}
#endif /* HAVE_LIBXML2 */