text: /*
   * Copyright (C) 2004-2014  Internet Systems Consortium, Inc. ("ISC")
   * Copyright (C) 1998-2003  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.
   */
  
  /* $Id$ */
  
  /*! \file */
  
  #include <config.h>
  
  #include <sys/param.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/stat.h>
  #include <sys/time.h>
  #include <sys/uio.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <stddef.h>
  #include <stdlib.h>
  #include <string.h>
  #include <unistd.h>
  
  #include <isc/buffer.h>
  #include <isc/bufferlist.h>
  #include <isc/condition.h>
  #include <isc/formatcheck.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/platform.h>
  #include <isc/print.h>
  #include <isc/region.h>
  #include <isc/socket.h>
  #include <isc/stats.h>
  #include <isc/strerror.h>
  #include <isc/task.h>
  #include <isc/thread.h>
  #include <isc/util.h>
  #include <isc/xml.h>
  
  #ifdef ISC_PLATFORM_HAVESYSUNH
  #include <sys/un.h>
  #endif
  #ifdef ISC_PLATFORM_HAVEKQUEUE
  #include <sys/event.h>
  #endif
  #ifdef ISC_PLATFORM_HAVEEPOLL
  #include <sys/epoll.h>
  #endif
  #ifdef ISC_PLATFORM_HAVEDEVPOLL
  #if defined(HAVE_SYS_DEVPOLL_H)
  #include <sys/devpoll.h>
  #elif defined(HAVE_DEVPOLL_H)
  #include <devpoll.h>
  #endif
  #endif
  
  #include "errno2result.h"
  
  /* See task.c about the following definition: */
  #ifdef BIND9
  #ifdef ISC_PLATFORM_USETHREADS
  #define USE_WATCHER_THREAD
  #else
  #define USE_SHARED_MANAGER
  #endif	/* ISC_PLATFORM_USETHREADS */
  #endif	/* BIND9 */
  
  #ifndef USE_WATCHER_THREAD
  #include "socket_p.h"
  #include "../task_p.h"
  #endif /* USE_WATCHER_THREAD */
  
  #if defined(SO_BSDCOMPAT) && defined(__linux__)
  #include <sys/utsname.h>
  #endif
  
  /*%
   * Choose the most preferable multiplex method.
   */
  #ifdef ISC_PLATFORM_HAVEKQUEUE
  #define USE_KQUEUE
  #elif defined (ISC_PLATFORM_HAVEEPOLL)
  #define USE_EPOLL
  #elif defined (ISC_PLATFORM_HAVEDEVPOLL)
  #define USE_DEVPOLL
  typedef struct {
  	unsigned int want_read : 1,
  		want_write : 1;
  } pollinfo_t;
  #else
  #define USE_SELECT
  #endif	/* ISC_PLATFORM_HAVEKQUEUE */
  
  #ifndef USE_WATCHER_THREAD
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
  struct isc_socketwait {
  	int nevents;
  };
  #elif defined (USE_SELECT)
  struct isc_socketwait {
  	fd_set *readset;
  	fd_set *writeset;
  	int nfds;
  	int maxfd;
  };
  #endif	/* USE_KQUEUE */
  #endif /* !USE_WATCHER_THREAD */
  
  /*%
   * Maximum number of allowable open sockets.  This is also the maximum
   * allowable socket file descriptor.
   *
   * Care should be taken before modifying this value for select():
   * The API standard doesn't ensure select() accept more than (the system default
   * of) FD_SETSIZE descriptors, and the default size should in fact be fine in
   * the vast majority of cases.  This constant should therefore be increased only
   * when absolutely necessary and possible, i.e., the server is exhausting all
   * available file descriptors (up to FD_SETSIZE) and the select() function
   * and FD_xxx macros support larger values than FD_SETSIZE (which may not
   * always by true, but we keep using some of them to ensure as much
   * portability as possible).  Note also that overall server performance
   * may be rather worsened with a larger value of this constant due to
   * inherent scalability problems of select().
   *
   * As a special note, this value shouldn't have to be touched if
   * this is a build for an authoritative only DNS server.
   */
  #ifndef ISC_SOCKET_MAXSOCKETS
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
  #define ISC_SOCKET_MAXSOCKETS 4096
  #elif defined(USE_SELECT)
  #define ISC_SOCKET_MAXSOCKETS FD_SETSIZE
  #endif	/* USE_KQUEUE... */
  #endif	/* ISC_SOCKET_MAXSOCKETS */
  
  #ifdef USE_SELECT
  /*%
   * Mac OS X needs a special definition to support larger values in select().
   * We always define this because a larger value can be specified run-time.
   */
  #ifdef __APPLE__
  #define _DARWIN_UNLIMITED_SELECT
  #endif	/* __APPLE__ */
  #endif	/* USE_SELECT */
  
  #ifdef ISC_SOCKET_USE_POLLWATCH
  /*%
   * If this macro is defined, enable workaround for a Solaris /dev/poll kernel
   * bug: DP_POLL ioctl could keep sleeping even if socket I/O is possible for
   * some of the specified FD.  The idea is based on the observation that it's
   * likely for a busy server to keep receiving packets.  It specifically works
   * as follows: the socket watcher is first initialized with the state of
   * "poll_idle".  While it's in the idle state it keeps sleeping until a socket
   * event occurs.  When it wakes up for a socket I/O event, it moves to the
   * poll_active state, and sets the poll timeout to a short period
   * (ISC_SOCKET_POLLWATCH_TIMEOUT msec).  If timeout occurs in this state, the
   * watcher goes to the poll_checking state with the same timeout period.
   * In this state, the watcher tries to detect whether this is a break
   * during intermittent events or the kernel bug is triggered.  If the next
   * polling reports an event within the short period, the previous timeout is
   * likely to be a kernel bug, and so the watcher goes back to the active state.
   * Otherwise, it moves to the idle state again.
   *
   * It's not clear whether this is a thread-related bug, but since we've only
   * seen this with threads, this workaround is used only when enabling threads.
   */
  
  typedef enum { poll_idle, poll_active, poll_checking } pollstate_t;
  
  #ifndef ISC_SOCKET_POLLWATCH_TIMEOUT
  #define ISC_SOCKET_POLLWATCH_TIMEOUT 10
  #endif	/* ISC_SOCKET_POLLWATCH_TIMEOUT */
  #endif	/* ISC_SOCKET_USE_POLLWATCH */
  
  /*%
   * Size of per-FD lock buckets.
   */
  #ifdef ISC_PLATFORM_USETHREADS
  #define FDLOCK_COUNT		1024
  #define FDLOCK_ID(fd)		((fd) % FDLOCK_COUNT)
  #else
  #define FDLOCK_COUNT		1
  #define FDLOCK_ID(fd)		0
  #endif	/* ISC_PLATFORM_USETHREADS */
  
  /*%
   * Maximum number of events communicated with the kernel.  There should normally
   * be no need for having a large number.
   */
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
  #ifndef ISC_SOCKET_MAXEVENTS
  #define ISC_SOCKET_MAXEVENTS	64
  #endif
  #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.
   *
   * For some reason, BSDI (and perhaps others) will sometimes return <0
   * from recv() but will have errno==0.  This is broken, but we have to
   * work around it here.
   */
  #define SOFT_ERROR(e)	((e) == EAGAIN || \
  			 (e) == EWOULDBLOCK || \
  			 (e) == EINTR || \
  			 (e) == 0)
  
  #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;
  
  #define SOCKET_MAGIC		ISC_MAGIC('I', 'O', 'i', 'o')
  #define VALID_SOCKET(s)		ISC_MAGIC_VALID(s, 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_HAVEIN6PKTINFO
  #ifndef USE_CMSG
  #define USE_CMSG	1
  #endif
  #endif
  
  /*%
   * NetBSD and FreeBSD can timestamp packets.  XXXMLG Should we have
   * a setsockopt() like interface to request timestamps, and if the OS
   * doesn't do it for us, call gettimeofday() on every UDP receive?
   */
  #ifdef SO_TIMESTAMP
  #ifndef USE_CMSG
  #define USE_CMSG	1
  #endif
  #endif
  
  /*%
   * The size to raise the receive buffer to (from BIND 8).
   */
  #define RCVBUFSIZE (32*1024)
  
  /*%
   * The number of times a send operation is repeated if the result is EINTR.
   */
  #define NRETRIES 10
  
  typedef struct isc__socket isc__socket_t;
  typedef struct isc__socketmgr isc__socketmgr_t;
  
  #define NEWCONNSOCK(ev) ((isc__socket_t *)(ev)->newsocket)
  
  struct isc__socket {
  	/* Not locked. */
  	isc_socket_t		common;
  	isc__socketmgr_t	*manager;
  	isc_mutex_t		lock;
  	isc_sockettype_t	type;
  	const isc_statscounter_t	*statsindex;
  
  	/* Locked by socket lock. */
  	ISC_LINK(isc__socket_t)	link;
  	unsigned int		references;
  	int			fd;
  	int			pf;
  	char				name[16];
  	void *				tag;
  
  	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;
  
  	/*
  	 * Internal events.  Posted when a descriptor is readable or
  	 * writable.  These are statically allocated and never freed.
  	 * They will be set to non-purgable before use.
  	 */
  	intev_t			readable_ev;
  	intev_t			writable_ev;
  
  	isc_sockaddr_t		peer_address;  /* remote address */
  
  	unsigned int		pending_recv : 1,
  				pending_send : 1,
  				pending_accept : 1,
  				listener : 1, /* listener socket */
  				connected : 1,
  				connecting : 1, /* connect pending */
  				bound : 1, /* bound to local addr */
  				dupped : 1;
  
  #ifdef ISC_NET_RECVOVERFLOW
  	unsigned char		overflow; /* used for MSG_TRUNC fake */
  #endif
  
  	char			*recvcmsgbuf;
  	ISC_SOCKADDR_LEN_T	recvcmsgbuflen;
  	char			*sendcmsgbuf;
  	ISC_SOCKADDR_LEN_T	sendcmsgbuflen;
  
  	void			*fdwatcharg;
  	isc_sockfdwatch_t	fdwatchcb;
  	int			fdwatchflags;
  	isc_task_t		*fdwatchtask;
  };
  
  #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. */
  	isc_socketmgr_t		common;
  	isc_mem_t	       *mctx;
  	isc_mutex_t		lock;
  	isc_mutex_t		*fdlock;
  	isc_stats_t		*stats;
  #ifdef USE_KQUEUE
  	int			kqueue_fd;
  	int			nevents;
  	struct kevent		*events;
  #endif	/* USE_KQUEUE */
  #ifdef USE_EPOLL
  	int			epoll_fd;
  	int			nevents;
  	struct epoll_event	*events;
  #endif	/* USE_EPOLL */
  #ifdef USE_DEVPOLL
  	int			devpoll_fd;
  	int			nevents;
  	struct pollfd		*events;
  #endif	/* USE_DEVPOLL */
  #ifdef USE_SELECT
  	int			fd_bufsize;
  #endif	/* USE_SELECT */
  	unsigned int		maxsocks;
  #ifdef ISC_PLATFORM_USETHREADS
  	int			pipe_fds[2];
  #endif
  
  	/* Locked by fdlock. */
  	isc__socket_t	       **fds;
  	int			*fdstate;
  #ifdef USE_DEVPOLL
  	pollinfo_t		*fdpollinfo;
  #endif
  
  	/* Locked by manager lock. */
  	ISC_LIST(isc__socket_t)	socklist;
  #ifdef USE_SELECT
  	fd_set			*read_fds;
  	fd_set			*read_fds_copy;
  	fd_set			*write_fds;
  	fd_set			*write_fds_copy;
  	int			maxfd;
  #endif	/* USE_SELECT */
  	int			reserved;	/* unlocked */
  #ifdef USE_WATCHER_THREAD
  	isc_thread_t		watcher;
  	isc_condition_t		shutdown_ok;
  #else /* USE_WATCHER_THREAD */
  	unsigned int		refs;
  #endif /* USE_WATCHER_THREAD */
  	int			maxudp;
  };
  
  #ifdef USE_SHARED_MANAGER
  static isc__socketmgr_t *socketmgr = NULL;
  #endif /* USE_SHARED_MANAGER */
  
  #define CLOSED			0	/* this one must be zero */
  #define MANAGED			1
  #define CLOSE_PENDING		2
  
  /*
   * send() and recv() iovec counts
   */
  #define MAXSCATTERGATHER_SEND	(ISC_SOCKET_MAXSCATTERGATHER)
  #ifdef ISC_NET_RECVOVERFLOW
  # define MAXSCATTERGATHER_RECV	(ISC_SOCKET_MAXSCATTERGATHER + 1)
  #else
  # define MAXSCATTERGATHER_RECV	(ISC_SOCKET_MAXSCATTERGATHER)
  #endif
  
  static isc_result_t socket_create(isc_socketmgr_t *manager0, int pf,
  				  isc_sockettype_t type,
  				  isc_socket_t **socketp,
  				  isc_socket_t *dup_socket);
  static void send_recvdone_event(isc__socket_t *, isc_socketevent_t **);
  static void send_senddone_event(isc__socket_t *, isc_socketevent_t **);
  static void free_socket(isc__socket_t **);
  static isc_result_t allocate_socket(isc__socketmgr_t *, isc_sockettype_t,
  				    isc__socket_t **);
  static void destroy(isc__socket_t **);
  static void internal_accept(isc_task_t *, isc_event_t *);
  static void internal_connect(isc_task_t *, isc_event_t *);
  static void internal_recv(isc_task_t *, isc_event_t *);
  static void internal_send(isc_task_t *, isc_event_t *);
  static void internal_fdwatch_write(isc_task_t *, isc_event_t *);
  static void internal_fdwatch_read(isc_task_t *, isc_event_t *);
  static void process_cmsg(isc__socket_t *, struct msghdr *, isc_socketevent_t *);
  static void build_msghdr_send(isc__socket_t *, isc_socketevent_t *,
  			      struct msghdr *, struct iovec *, size_t *);
  static void build_msghdr_recv(isc__socket_t *, isc_socketevent_t *,
  			      struct msghdr *, struct iovec *, size_t *);
  #ifdef USE_WATCHER_THREAD
  static isc_boolean_t process_ctlfd(isc__socketmgr_t *manager);
  #endif
  
  /*%
   * The following can be either static or public, depending on build environment.
   */
  
  #ifdef BIND9
  #define ISC_SOCKETFUNC_SCOPE
  #else
  #define ISC_SOCKETFUNC_SCOPE static
  #endif
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_create(isc_socketmgr_t *manager, int pf, isc_sockettype_t type,
  		   isc_socket_t **socketp);
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_attach(isc_socket_t *sock, isc_socket_t **socketp);
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_detach(isc_socket_t **socketp);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socketmgr_create(isc_mem_t *mctx, isc_socketmgr_t **managerp);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socketmgr_create2(isc_mem_t *mctx, isc_socketmgr_t **managerp,
  		       unsigned int maxsocks);
  ISC_SOCKETFUNC_SCOPE void
  isc__socketmgr_destroy(isc_socketmgr_t **managerp);
  ISC_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE 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);
  ISC_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE 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);
  ISC_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_sendtov2(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,
  		     unsigned int flags);
  ISC_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE void
  isc__socket_cleanunix(isc_sockaddr_t *sockaddr, isc_boolean_t active);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_permunix(isc_sockaddr_t *sockaddr, isc_uint32_t perm,
  		     isc_uint32_t owner, isc_uint32_t group);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_bind(isc_socket_t *sock, isc_sockaddr_t *sockaddr,
  		 unsigned int options);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_filter(isc_socket_t *sock, const char *filter);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_listen(isc_socket_t *sock, unsigned int backlog);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_accept(isc_socket_t *sock,
  		   isc_task_t *task, isc_taskaction_t action, const void *arg);
  ISC_SOCKETFUNC_SCOPE 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);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_getpeername(isc_socket_t *sock, isc_sockaddr_t *addressp);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_getsockname(isc_socket_t *sock, isc_sockaddr_t *addressp);
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_cancel(isc_socket_t *sock, isc_task_t *task, unsigned int how);
  ISC_SOCKETFUNC_SCOPE isc_sockettype_t
  isc__socket_gettype(isc_socket_t *sock);
  ISC_SOCKETFUNC_SCOPE isc_boolean_t
  isc__socket_isbound(isc_socket_t *sock);
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_ipv6only(isc_socket_t *sock, isc_boolean_t yes);
  #if defined(HAVE_LIBXML2) && defined(BIND9)
  ISC_SOCKETFUNC_SCOPE void
  isc__socketmgr_renderxml(isc_socketmgr_t *mgr0, xmlTextWriterPtr writer);
  #endif
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_fdwatchcreate(isc_socketmgr_t *manager, int fd, int flags,
  			  isc_sockfdwatch_t callback, void *cbarg,
  			  isc_task_t *task, isc_socket_t **socketp);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_fdwatchpoke(isc_socket_t *sock, int flags);
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_dup(isc_socket_t *sock, isc_socket_t **socketp);
  ISC_SOCKETFUNC_SCOPE int
  isc__socket_getfd(isc_socket_t *sock);
  
  static struct {
  	isc_socketmethods_t methods;
  
  	/*%
  	 * The following are defined just for avoiding unused static functions.
  	 */
  #ifndef BIND9
  	void *recvv, *send, *sendv, *sendto2, *sendtov, *cleanunix, *permunix,
  	     *filter, *listen, *accept, *getpeername, *isbound;
  #endif
  } socketmethods = {
  	{
  		isc__socket_attach,
  		isc__socket_detach,
  		isc__socket_bind,
  		isc__socket_sendto,
  		isc__socket_sendto2,
  		isc__socket_connect,
  		isc__socket_recv,
  		isc__socket_recv2,
  		isc__socket_cancel,
  		isc__socket_getsockname,
  		isc__socket_gettype,
  		isc__socket_ipv6only,
  		isc__socket_fdwatchpoke,
  		isc__socket_dup,
  		isc__socket_getfd
  	}
  #ifndef BIND9
  	,
  	(void *)isc__socket_recvv, (void *)isc__socket_send,
  	(void *)isc__socket_sendv, (void *)isc__socket_sendto2,
  	(void *)isc__socket_sendtov,
  	(void *)isc__socket_cleanunix, (void *)isc__socket_permunix,
  	(void *)isc__socket_filter, (void *)isc__socket_listen,
  	(void *)isc__socket_accept, (void *)isc__socket_getpeername,
  	(void *)isc__socket_isbound
  #endif
  };
  
  static isc_socketmgrmethods_t socketmgrmethods = {
  	isc__socketmgr_destroy,
  	isc__socket_create,
  	isc__socket_fdwatchcreate
  };
  
  #define SELECT_POKE_SHUTDOWN		(-1)
  #define SELECT_POKE_NOTHING		(-2)
  #define SELECT_POKE_READ		(-3)
  #define SELECT_POKE_ACCEPT		(-3) /*%< Same as _READ */
  #define SELECT_POKE_WRITE		(-4)
  #define SELECT_POKE_CONNECT		(-4) /*%< Same as _WRITE */
  #define SELECT_POKE_CLOSE		(-5)
  
  #define SOCK_DEAD(s)			((s)->references == 0)
  
  /*%
   * Shortcut index arrays to get access to statistics counters.
   */
  enum {
  	STATID_OPEN = 0,
  	STATID_OPENFAIL = 1,
  	STATID_CLOSE = 2,
  	STATID_BINDFAIL = 3,
  	STATID_CONNECTFAIL = 4,
  	STATID_CONNECT = 5,
  	STATID_ACCEPTFAIL = 6,
  	STATID_ACCEPT = 7,
  	STATID_SENDFAIL = 8,
  	STATID_RECVFAIL = 9
  };
  static const isc_statscounter_t udp4statsindex[] = {
  	isc_sockstatscounter_udp4open,
  	isc_sockstatscounter_udp4openfail,
  	isc_sockstatscounter_udp4close,
  	isc_sockstatscounter_udp4bindfail,
  	isc_sockstatscounter_udp4connectfail,
  	isc_sockstatscounter_udp4connect,
  	-1,
  	-1,
  	isc_sockstatscounter_udp4sendfail,
  	isc_sockstatscounter_udp4recvfail
  };
  static const isc_statscounter_t udp6statsindex[] = {
  	isc_sockstatscounter_udp6open,
  	isc_sockstatscounter_udp6openfail,
  	isc_sockstatscounter_udp6close,
  	isc_sockstatscounter_udp6bindfail,
  	isc_sockstatscounter_udp6connectfail,
  	isc_sockstatscounter_udp6connect,
  	-1,
  	-1,
  	isc_sockstatscounter_udp6sendfail,
  	isc_sockstatscounter_udp6recvfail
  };
  static const isc_statscounter_t tcp4statsindex[] = {
  	isc_sockstatscounter_tcp4open,
  	isc_sockstatscounter_tcp4openfail,
  	isc_sockstatscounter_tcp4close,
  	isc_sockstatscounter_tcp4bindfail,
  	isc_sockstatscounter_tcp4connectfail,
  	isc_sockstatscounter_tcp4connect,
  	isc_sockstatscounter_tcp4acceptfail,
  	isc_sockstatscounter_tcp4accept,
  	isc_sockstatscounter_tcp4sendfail,
  	isc_sockstatscounter_tcp4recvfail
  };
  static const isc_statscounter_t tcp6statsindex[] = {
  	isc_sockstatscounter_tcp6open,
  	isc_sockstatscounter_tcp6openfail,
  	isc_sockstatscounter_tcp6close,
  	isc_sockstatscounter_tcp6bindfail,
  	isc_sockstatscounter_tcp6connectfail,
  	isc_sockstatscounter_tcp6connect,
  	isc_sockstatscounter_tcp6acceptfail,
  	isc_sockstatscounter_tcp6accept,
  	isc_sockstatscounter_tcp6sendfail,
  	isc_sockstatscounter_tcp6recvfail
  };
  static const isc_statscounter_t unixstatsindex[] = {
  	isc_sockstatscounter_unixopen,
  	isc_sockstatscounter_unixopenfail,
  	isc_sockstatscounter_unixclose,
  	isc_sockstatscounter_unixbindfail,
  	isc_sockstatscounter_unixconnectfail,
  	isc_sockstatscounter_unixconnect,
  	isc_sockstatscounter_unixacceptfail,
  	isc_sockstatscounter_unixaccept,
  	isc_sockstatscounter_unixsendfail,
  	isc_sockstatscounter_unixrecvfail
  };
  static const isc_statscounter_t fdwatchstatsindex[] = {
  	-1,
  	-1,
  	isc_sockstatscounter_fdwatchclose,
  	isc_sockstatscounter_fdwatchbindfail,
  	isc_sockstatscounter_fdwatchconnectfail,
  	isc_sockstatscounter_fdwatchconnect,
  	-1,
  	-1,
  	isc_sockstatscounter_fdwatchsendfail,
  	isc_sockstatscounter_fdwatchrecvfail
  };
  
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL) || \
      defined(USE_WATCHER_THREAD)
  static void
  manager_log(isc__socketmgr_t *sockmgr,
  	    isc_logcategory_t *category, isc_logmodule_t *module, int level,
  	    const char *fmt, ...) ISC_FORMAT_PRINTF(5, 6);
  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);
  }
  #endif
  
  static void
  socket_log(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);
  static void
  socket_log(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[ISC_SOCKADDR_FORMATSIZE];
  	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: %s", sock, msgbuf);
  	} else {
  		isc_sockaddr_format(address, peerbuf, sizeof(peerbuf));
  		isc_log_iwrite(isc_lctx, category, module, level,
  			       msgcat, msgset, message,
  			       "socket %p %s: %s", sock, peerbuf, msgbuf);
  	}
  }
  
  #if defined(_AIX) && defined(ISC_NET_BSD44MSGHDR) && \
      defined(USE_CMSG) && defined(IPV6_RECVPKTINFO)
  /*
   * AIX has a kernel bug where IPV6_RECVPKTINFO gets cleared by
   * setting IPV6_V6ONLY.
   */
  static void
  FIX_IPV6_RECVPKTINFO(isc__socket_t *sock)
  {
  	char strbuf[ISC_STRERRORSIZE];
  	int on = 1;
  
  	if (sock->pf != AF_INET6 || sock->type != isc_sockettype_udp)
  		return;
  
  	if (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
  		       (void *)&on, sizeof(on)) < 0) {
  
  		isc__strerror(errno, 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
  #define FIX_IPV6_RECVPKTINFO(sock) (void)0
  #endif
  
  /*%
   * Increment socket-related statistics counters.
   */
  static inline void
  inc_stats(isc_stats_t *stats, isc_statscounter_t counterid) {
  	REQUIRE(counterid != -1);
  
  	if (stats != NULL)
  		isc_stats_increment(stats, counterid);
  }
  
  static inline isc_result_t
  watch_fd(isc__socketmgr_t *manager, int fd, int msg) {
  	isc_result_t result = ISC_R_SUCCESS;
  
  #ifdef USE_KQUEUE
  	struct kevent evchange;
  
  	memset(&evchange, 0, sizeof(evchange));
  	if (msg == SELECT_POKE_READ)
  		evchange.filter = EVFILT_READ;
  	else
  		evchange.filter = EVFILT_WRITE;
  	evchange.flags = EV_ADD;
  	evchange.ident = fd;
  	if (kevent(manager->kqueue_fd, &evchange, 1, NULL, 0, NULL) != 0)
  		result = isc__errno2result(errno);
  
  	return (result);
  #elif defined(USE_EPOLL)
  	struct epoll_event event;
  
  	if (msg == SELECT_POKE_READ)
  		event.events = EPOLLIN;
  	else
  		event.events = EPOLLOUT;
  	memset(&event.data, 0, sizeof(event.data));
  	event.data.fd = fd;
  	if (epoll_ctl(manager->epoll_fd, EPOLL_CTL_ADD, fd, &event) == -1 &&
  	    errno != EEXIST) {
  		result = isc__errno2result(errno);
  	}
  
  	return (result);
  #elif defined(USE_DEVPOLL)
  	struct pollfd pfd;
  	int lockid = FDLOCK_ID(fd);
  
  	memset(&pfd, 0, sizeof(pfd));
  	if (msg == SELECT_POKE_READ)
  		pfd.events = POLLIN;
  	else
  		pfd.events = POLLOUT;
  	pfd.fd = fd;
  	pfd.revents = 0;
  	LOCK(&manager->fdlock[lockid]);
  	if (write(manager->devpoll_fd, &pfd, sizeof(pfd)) == -1)
  		result = isc__errno2result(errno);
  	else {
  		if (msg == SELECT_POKE_READ)
  			manager->fdpollinfo[fd].want_read = 1;
  		else
  			manager->fdpollinfo[fd].want_write = 1;
  	}
  	UNLOCK(&manager->fdlock[lockid]);
  
  	return (result);
  #elif defined(USE_SELECT)
  	LOCK(&manager->lock);
  	if (msg == SELECT_POKE_READ)
  		FD_SET(fd, manager->read_fds);
  	if (msg == SELECT_POKE_WRITE)
  		FD_SET(fd, manager->write_fds);
  	UNLOCK(&manager->lock);
  
  	return (result);
  #endif
  }
  
  static inline isc_result_t
  unwatch_fd(isc__socketmgr_t *manager, int fd, int msg) {
  	isc_result_t result = ISC_R_SUCCESS;
  
  #ifdef USE_KQUEUE
  	struct kevent evchange;
  
  	memset(&evchange, 0, sizeof(evchange));
  	if (msg == SELECT_POKE_READ)
  		evchange.filter = EVFILT_READ;
  	else
  		evchange.filter = EVFILT_WRITE;
  	evchange.flags = EV_DELETE;
  	evchange.ident = fd;
  	if (kevent(manager->kqueue_fd, &evchange, 1, NULL, 0, NULL) != 0)
  		result = isc__errno2result(errno);
  
  	return (result);
  #elif defined(USE_EPOLL)
  	struct epoll_event event;
  
  	if (msg == SELECT_POKE_READ)
  		event.events = EPOLLIN;
  	else
  		event.events = EPOLLOUT;
  	memset(&event.data, 0, sizeof(event.data));
  	event.data.fd = fd;
  	if (epoll_ctl(manager->epoll_fd, EPOLL_CTL_DEL, fd, &event) == -1 &&
  	    errno != ENOENT) {
  		char strbuf[ISC_STRERRORSIZE];
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "epoll_ctl(DEL), %d: %s", fd, strbuf);
  		result = ISC_R_UNEXPECTED;
  	}
  	return (result);
  #elif defined(USE_DEVPOLL)
  	struct pollfd pfds[2];
  	size_t writelen = sizeof(pfds[0]);
  	int lockid = FDLOCK_ID(fd);
  
  	memset(pfds, 0, sizeof(pfds));
  	pfds[0].events = POLLREMOVE;
  	pfds[0].fd = fd;
  
  	/*
  	 * Canceling read or write polling via /dev/poll is tricky.  Since it
  	 * only provides a way of canceling per FD, we may need to re-poll the
  	 * socket for the other operation.
  	 */
  	LOCK(&manager->fdlock[lockid]);
  	if (msg == SELECT_POKE_READ &&
  	    manager->fdpollinfo[fd].want_write == 1) {
  		pfds[1].events = POLLOUT;
  		pfds[1].fd = fd;
  		writelen += sizeof(pfds[1]);
  	}
  	if (msg == SELECT_POKE_WRITE &&
  	    manager->fdpollinfo[fd].want_read == 1) {
  		pfds[1].events = POLLIN;
  		pfds[1].fd = fd;
  		writelen += sizeof(pfds[1]);
  	}
  
  	if (write(manager->devpoll_fd, pfds, writelen) == -1)
  		result = isc__errno2result(errno);
  	else {
  		if (msg == SELECT_POKE_READ)
  			manager->fdpollinfo[fd].want_read = 0;
  		else
  			manager->fdpollinfo[fd].want_write = 0;
  	}
  	UNLOCK(&manager->fdlock[lockid]);
  
  	return (result);
  #elif defined(USE_SELECT)
  	LOCK(&manager->lock);
  	if (msg == SELECT_POKE_READ)
  		FD_CLR(fd, manager->read_fds);
  	else if (msg == SELECT_POKE_WRITE)
  		FD_CLR(fd, manager->write_fds);
  	UNLOCK(&manager->lock);
  
  	return (result);
  #endif
  }
  
  static void
  wakeup_socket(isc__socketmgr_t *manager, int fd, int msg) {
  	isc_result_t result;
  	int lockid = FDLOCK_ID(fd);
  
  	/*
  	 * This is a wakeup on a socket.  If the socket is not in the
  	 * process of being closed, start watching it for either reads
  	 * or writes.
  	 */
  
  	INSIST(fd >= 0 && fd < (int)manager->maxsocks);
  
  	if (msg == SELECT_POKE_CLOSE) {
  		/* No one should be updating fdstate, so no need to lock it */
  		INSIST(manager->fdstate[fd] == CLOSE_PENDING);
  		manager->fdstate[fd] = CLOSED;
  		(void)unwatch_fd(manager, fd, SELECT_POKE_READ);
  		(void)unwatch_fd(manager, fd, SELECT_POKE_WRITE);
  		(void)close(fd);
  		return;
  	}
  
  	LOCK(&manager->fdlock[lockid]);
  	if (manager->fdstate[fd] == CLOSE_PENDING) {
  		UNLOCK(&manager->fdlock[lockid]);
  
  		/*
  		 * We accept (and ignore) any error from unwatch_fd() as we are
  		 * closing the socket, hoping it doesn't leave dangling state in
  		 * the kernel.
  		 * Note that unwatch_fd() must be called after releasing the
  		 * fdlock; otherwise it could cause deadlock due to a lock order
  		 * reversal.
  		 */
  		(void)unwatch_fd(manager, fd, SELECT_POKE_READ);
  		(void)unwatch_fd(manager, fd, SELECT_POKE_WRITE);
  		return;
  	}
  	if (manager->fdstate[fd] != MANAGED) {
  		UNLOCK(&manager->fdlock[lockid]);
  		return;
  	}
  	UNLOCK(&manager->fdlock[lockid]);
  
  	/*
  	 * Set requested bit.
  	 */
  	result = watch_fd(manager, fd, msg);
  	if (result != ISC_R_SUCCESS) {
  		/*
  		 * XXXJT: what should we do?  Ignoring the failure of watching
  		 * a socket will make the application dysfunctional, but there
  		 * seems to be no reasonable recovery process.
  		 */
  		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  			      "failed to start watching FD (%d): %s",
  			      fd, isc_result_totext(result));
  	}
  }
  
  #ifdef USE_WATCHER_THREAD
  /*
   * Poke the select loop when there is something for us to do.
   * The write is required (by POSIX) to complete.  That is, we
   * will not get partial writes.
   */
  static void
  select_poke(isc__socketmgr_t *mgr, int fd, int msg) {
  	int cc;
  	int buf[2];
  	char strbuf[ISC_STRERRORSIZE];
  
  	buf[0] = fd;
  	buf[1] = msg;
  
  	do {
  		cc = write(mgr->pipe_fds[1], buf, sizeof(buf));
  #ifdef ENOSR
  		/*
  		 * Treat ENOSR as EAGAIN but loop slowly as it is
  		 * unlikely to clear fast.
  		 */
  		if (cc < 0 && errno == ENOSR) {
  			sleep(1);
  			errno = EAGAIN;
  		}
  #endif
  	} while (cc < 0 && SOFT_ERROR(errno));
  
  	if (cc < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		FATAL_ERROR(__FILE__, __LINE__,
  			    isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
  					   ISC_MSG_WRITEFAILED,
  					   "write() failed "
  					   "during watcher poke: %s"),
  			    strbuf);
  	}
  
  	INSIST(cc == sizeof(buf));
  }
  
  /*
   * Read a message on the internal fd.
   */
  static void
  select_readmsg(isc__socketmgr_t *mgr, int *fd, int *msg) {
  	int buf[2];
  	int cc;
  	char strbuf[ISC_STRERRORSIZE];
  
  	cc = read(mgr->pipe_fds[0], buf, sizeof(buf));
  	if (cc < 0) {
  		*msg = SELECT_POKE_NOTHING;
  		*fd = -1;	/* Silence compiler. */
  		if (SOFT_ERROR(errno))
  			return;
  
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		FATAL_ERROR(__FILE__, __LINE__,
  			    isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
  					   ISC_MSG_READFAILED,
  					   "read() failed "
  					   "during watcher poke: %s"),
  			    strbuf);
  
  		return;
  	}
  	INSIST(cc == sizeof(buf));
  
  	*fd = buf[0];
  	*msg = buf[1];
  }
  #else /* USE_WATCHER_THREAD */
  /*
   * Update the state of the socketmgr when something changes.
   */
  static void
  select_poke(isc__socketmgr_t *manager, int fd, int msg) {
  	if (msg == SELECT_POKE_SHUTDOWN)
  		return;
  	else if (fd >= 0)
  		wakeup_socket(manager, fd, msg);
  	return;
  }
  #endif /* USE_WATCHER_THREAD */
  
  /*
   * Make a fd non-blocking.
   */
  static isc_result_t
  make_nonblock(int fd) {
  	int ret;
  	int flags;
  	char strbuf[ISC_STRERRORSIZE];
  #ifdef USE_FIONBIO_IOCTL
  	int on = 1;
  
  	ret = ioctl(fd, FIONBIO, (char *)&on);
  #else
  	flags = fcntl(fd, F_GETFL, 0);
  	flags |= PORT_NONBLOCK;
  	ret = fcntl(fd, F_SETFL, flags);
  #endif
  
  	if (ret == -1) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  #ifdef USE_FIONBIO_IOCTL
  				 "ioctl(%d, FIONBIO, &on): %s", fd,
  #else
  				 "fcntl(%d, F_SETFL, %d): %s", fd, flags,
  #endif
  				 strbuf);
  
  		return (ISC_R_UNEXPECTED);
  	}
  
  	return (ISC_R_SUCCESS);
  }
  
  #ifdef USE_CMSG
  /*
   * Not all OSes support advanced CMSG macros: CMSG_LEN and CMSG_SPACE.
   * In order to ensure as much portability as possible, we provide wrapper
   * functions of these macros.
   * Note that cmsg_space() could run slow on OSes that do not have
   * CMSG_SPACE.
   */
  static inline ISC_SOCKADDR_LEN_T
  cmsg_len(ISC_SOCKADDR_LEN_T len) {
  #ifdef CMSG_LEN
  	return (CMSG_LEN(len));
  #else
  	ISC_SOCKADDR_LEN_T hdrlen;
  
  	/*
  	 * Cast NULL so that any pointer arithmetic performed by CMSG_DATA
  	 * is correct.
  	 */
  	hdrlen = (ISC_SOCKADDR_LEN_T)CMSG_DATA(((struct cmsghdr *)NULL));
  	return (hdrlen + len);
  #endif
  }
  
  static inline ISC_SOCKADDR_LEN_T
  cmsg_space(ISC_SOCKADDR_LEN_T len) {
  #ifdef CMSG_SPACE
  	return (CMSG_SPACE(len));
  #else
  	struct msghdr msg;
  	struct cmsghdr *cmsgp;
  	/*
  	 * XXX: The buffer length is an ad-hoc value, but should be enough
  	 * in a practical sense.
  	 */
  	char dummybuf[sizeof(struct cmsghdr) + 1024];
  
  	memset(&msg, 0, sizeof(msg));
  	msg.msg_control = dummybuf;
  	msg.msg_controllen = sizeof(dummybuf);
  
  	cmsgp = (struct cmsghdr *)dummybuf;
  	cmsgp->cmsg_len = cmsg_len(len);
  
  	cmsgp = CMSG_NXTHDR(&msg, cmsgp);
  	if (cmsgp != NULL)
  		return ((char *)cmsgp - (char *)msg.msg_control);
  	else
  		return (0);
  #endif
  }
  #endif /* USE_CMSG */
  
  /*
   * Process control messages received on a socket.
   */
  static void
  process_cmsg(isc__socket_t *sock, struct msghdr *msg, isc_socketevent_t *dev) {
  #ifdef USE_CMSG
  	struct cmsghdr *cmsgp;
  #ifdef ISC_PLATFORM_HAVEIN6PKTINFO
  	struct in6_pktinfo *pktinfop;
  #endif
  #ifdef SO_TIMESTAMP
  	void *timevalp;
  #endif
  #endif
  
  	/*
  	 * sock is used only when ISC_NET_BSD44MSGHDR and USE_CMSG are defined.
  	 * msg and dev are used only when ISC_NET_BSD44MSGHDR is defined.
  	 * They are all here, outside of the CPP tests, because it is
  	 * more consistent with the usual ISC coding style.
  	 */
  	UNUSED(sock);
  	UNUSED(msg);
  	UNUSED(dev);
  
  #ifdef ISC_NET_BSD44MSGHDR
  
  #ifdef MSG_TRUNC
  	if ((msg->msg_flags & MSG_TRUNC) == MSG_TRUNC)
  		dev->attributes |= ISC_SOCKEVENTATTR_TRUNC;
  #endif
  
  #ifdef MSG_CTRUNC
  	if ((msg->msg_flags & MSG_CTRUNC) == MSG_CTRUNC)
  		dev->attributes |= ISC_SOCKEVENTATTR_CTRUNC;
  #endif
  
  #ifndef USE_CMSG
  	return;
  #else
  	if (msg->msg_controllen == 0U || msg->msg_control == NULL)
  		return;
  
  #ifdef SO_TIMESTAMP
  	timevalp = NULL;
  #endif
  #ifdef ISC_PLATFORM_HAVEIN6PKTINFO
  	pktinfop = NULL;
  #endif
  
  	cmsgp = CMSG_FIRSTHDR(msg);
  	while (cmsgp != NULL) {
  		socket_log(sock, NULL, TRACE,
  			   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_PROCESSCMSG,
  			   "processing cmsg %p", cmsgp);
  
  #ifdef ISC_PLATFORM_HAVEIN6PKTINFO
  		if (cmsgp->cmsg_level == IPPROTO_IPV6
  		    && cmsgp->cmsg_type == IPV6_PKTINFO) {
  
  			pktinfop = (struct in6_pktinfo *)CMSG_DATA(cmsgp);
  			memmove(&dev->pktinfo, pktinfop,
  				sizeof(struct in6_pktinfo));
  			dev->attributes |= ISC_SOCKEVENTATTR_PKTINFO;
  			socket_log(sock, NULL, TRACE,
  				   isc_msgcat, ISC_MSGSET_SOCKET,
  				   ISC_MSG_IFRECEIVED,
  				   "interface received on ifindex %u",
  				   dev->pktinfo.ipi6_ifindex);
  			if (IN6_IS_ADDR_MULTICAST(&pktinfop->ipi6_addr))
  				dev->attributes |= ISC_SOCKEVENTATTR_MULTICAST;
  			goto next;
  		}
  #endif
  
  #ifdef SO_TIMESTAMP
  		if (cmsgp->cmsg_level == SOL_SOCKET
  		    && cmsgp->cmsg_type == SCM_TIMESTAMP) {
  			struct timeval tv;
  			timevalp = CMSG_DATA(cmsgp);
  			memmove(&tv, timevalp, sizeof(tv));
  			dev->timestamp.seconds = tv.tv_sec;
  			dev->timestamp.nanoseconds = tv.tv_usec * 1000;
  			dev->attributes |= ISC_SOCKEVENTATTR_TIMESTAMP;
  			goto next;
  		}
  #endif
  
  	next:
  		cmsgp = CMSG_NXTHDR(msg, cmsgp);
  	}
  #endif /* USE_CMSG */
  
  #endif /* ISC_NET_BSD44MSGHDR */
  }
  
  /*
   * 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.
   *
   * If write_countp != NULL, *write_countp will hold the number of bytes
   * this transaction can send.
   */
  static void
  build_msghdr_send(isc__socket_t *sock, isc_socketevent_t *dev,
  		  struct msghdr *msg, struct iovec *iov, size_t *write_countp)
  {
  	unsigned int iovcount;
  	isc_buffer_t *buffer;
  	isc_region_t used;
  	size_t write_count;
  	size_t skip_count;
  
  	memset(msg, 0, sizeof(*msg));
  
  	if (!sock->connected) {
  		msg->msg_name = (void *)&dev->address.type.sa;
  		msg->msg_namelen = dev->address.length;
  	} else {
  		msg->msg_name = NULL;
  		msg->msg_namelen = 0;
  	}
  
  	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;
  		iov[0].iov_base = (void *)(dev->region.base + dev->n);
  		iov[0].iov_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) {
  			iov[iovcount].iov_base = (void *)(used.base
  							  + skip_count);
  			iov[iovcount].iov_len = used.length - skip_count;
  			write_count += (used.length - skip_count);
  			skip_count = 0;
  			iovcount++;
  		}
  		buffer = ISC_LIST_NEXT(buffer, link);
  	}
  
  	INSIST(skip_count == 0U);
  
   config:
  	msg->msg_iov = iov;
  	msg->msg_iovlen = iovcount;
  
  #ifdef ISC_NET_BSD44MSGHDR
  	msg->msg_control = NULL;
  	msg->msg_controllen = 0;
  	msg->msg_flags = 0;
  #if defined(USE_CMSG) && defined(ISC_PLATFORM_HAVEIN6PKTINFO)
  	if ((sock->type == isc_sockettype_udp)
  	    && ((dev->attributes & ISC_SOCKEVENTATTR_PKTINFO) != 0)) {
  #if defined(IPV6_USE_MIN_MTU)
  		int use_min_mtu = 1;	/* -1, 0, 1 */
  #endif
  		struct cmsghdr *cmsgp;
  		struct in6_pktinfo *pktinfop;
  
  		socket_log(sock, NULL, TRACE,
  			   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_SENDTODATA,
  			   "sendto pktinfo data, ifindex %u",
  			   dev->pktinfo.ipi6_ifindex);
  
  		msg->msg_controllen = cmsg_space(sizeof(struct in6_pktinfo));
  		INSIST(msg->msg_controllen <= sock->sendcmsgbuflen);
  		msg->msg_control = (void *)sock->sendcmsgbuf;
  
  		cmsgp = (struct cmsghdr *)sock->sendcmsgbuf;
  		cmsgp->cmsg_level = IPPROTO_IPV6;
  		cmsgp->cmsg_type = IPV6_PKTINFO;
  		cmsgp->cmsg_len = cmsg_len(sizeof(struct in6_pktinfo));
  		pktinfop = (struct in6_pktinfo *)CMSG_DATA(cmsgp);
  		memmove(pktinfop, &dev->pktinfo, sizeof(struct in6_pktinfo));
  #if defined(IPV6_USE_MIN_MTU)
  		/*
  		 * Set IPV6_USE_MIN_MTU as a per packet option as FreeBSD
  		 * ignores setsockopt(IPV6_USE_MIN_MTU) when IPV6_PKTINFO
  		 * is used.
  		 */
  		cmsgp = (struct cmsghdr *)(sock->sendcmsgbuf +
  					   msg->msg_controllen);
  		msg->msg_controllen += cmsg_space(sizeof(use_min_mtu));
  		INSIST(msg->msg_controllen <= sock->sendcmsgbuflen);
  
  		cmsgp->cmsg_level = IPPROTO_IPV6;
  		cmsgp->cmsg_type = IPV6_USE_MIN_MTU;
  		cmsgp->cmsg_len = cmsg_len(sizeof(use_min_mtu));
  		memmove(CMSG_DATA(cmsgp), &use_min_mtu, sizeof(use_min_mtu));
  #endif
  	}
  #endif /* USE_CMSG && ISC_PLATFORM_HAVEIPV6 */
  #else /* ISC_NET_BSD44MSGHDR */
  	msg->msg_accrights = NULL;
  	msg->msg_accrightslen = 0;
  #endif /* ISC_NET_BSD44MSGHDR */
  
  	if (write_countp != NULL)
  		*write_countp = write_count;
  }
  
  /*
   * Construct an iov array and attach it to the msghdr passed in.  This is
   * the RECV constructor, which will use the available 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.
   *
   * If read_countp != NULL, *read_countp will hold the number of bytes
   * this transaction can receive.
   */
  static void
  build_msghdr_recv(isc__socket_t *sock, isc_socketevent_t *dev,
  		  struct msghdr *msg, struct iovec *iov, size_t *read_countp)
  {
  	unsigned int iovcount;
  	isc_buffer_t *buffer;
  	isc_region_t available;
  	size_t read_count;
  
  	memset(msg, 0, sizeof(struct msghdr));
  
  	if (sock->type == isc_sockettype_udp) {
  		memset(&dev->address, 0, sizeof(dev->address));
  #ifdef BROKEN_RECVMSG
  		if (sock->pf == AF_INET) {
  			msg->msg_name = (void *)&dev->address.type.sin;
  			msg->msg_namelen = sizeof(dev->address.type.sin6);
  		} else if (sock->pf == AF_INET6) {
  			msg->msg_name = (void *)&dev->address.type.sin6;
  			msg->msg_namelen = sizeof(dev->address.type.sin6);
  #ifdef ISC_PLATFORM_HAVESYSUNH
  		} else if (sock->pf == AF_UNIX) {
  			msg->msg_name = (void *)&dev->address.type.sunix;
  			msg->msg_namelen = sizeof(dev->address.type.sunix);
  #endif
  		} else {
  			msg->msg_name = (void *)&dev->address.type.sa;
  			msg->msg_namelen = sizeof(dev->address.type);
  		}
  #else
  		msg->msg_name = (void *)&dev->address.type.sa;
  		msg->msg_namelen = sizeof(dev->address.type);
  #endif
  #ifdef ISC_NET_RECVOVERFLOW
  		/* If needed, steal one iovec for overflow detection. */
  		maxiov--;
  #endif
  	} else { /* TCP */
  		msg->msg_name = NULL;
  		msg->msg_namelen = 0;
  		dev->address = sock->peer_address;
  	}
  
  	buffer = ISC_LIST_HEAD(dev->bufferlist);
  	read_count = 0;
  
  	/*
  	 * Single buffer I/O?  Skip what we've done so far in this region.
  	 */
  	if (buffer == NULL) {
  		read_count = dev->region.length - dev->n;
  		iov[0].iov_base = (void *)(dev->region.base + dev->n);
  		iov[0].iov_len = read_count;
  		iovcount = 1;
  
  		goto config;
  	}
  
  	/*
  	 * Multibuffer I/O.
  	 * Skip empty buffers.
  	 */
  	while (buffer != NULL) {
  		REQUIRE(ISC_BUFFER_VALID(buffer));
  		if (isc_buffer_availablelength(buffer) != 0)
  			break;
  		buffer = ISC_LIST_NEXT(buffer, link);
  	}
  
  	iovcount = 0;
  	while (buffer != NULL) {
  		INSIST(iovcount < MAXSCATTERGATHER_RECV);
  
  		isc_buffer_availableregion(buffer, &available);
  
  		if (available.length > 0) {
  			iov[iovcount].iov_base = (void *)(available.base);
  			iov[iovcount].iov_len = available.length;
  			read_count += available.length;
  			iovcount++;
  		}
  		buffer = ISC_LIST_NEXT(buffer, link);
  	}
  
   config:
  
  	/*
  	 * If needed, set up to receive that one extra byte.  Note that
  	 * we know there is at least one iov left, since we stole it
  	 * at the top of this function.
  	 */
  #ifdef ISC_NET_RECVOVERFLOW
  	if (sock->type == isc_sockettype_udp) {
  		iov[iovcount].iov_base = (void *)(&sock->overflow);
  		iov[iovcount].iov_len = 1;
  		iovcount++;
  	}
  #endif
  
  	msg->msg_iov = iov;
  	msg->msg_iovlen = iovcount;
  
  #ifdef ISC_NET_BSD44MSGHDR
  	msg->msg_control = NULL;
  	msg->msg_controllen = 0;
  	msg->msg_flags = 0;
  #if defined(USE_CMSG)
  	if (sock->type == isc_sockettype_udp) {
  		msg->msg_control = sock->recvcmsgbuf;
  		msg->msg_controllen = sock->recvcmsgbuflen;
  	}
  #endif /* USE_CMSG */
  #else /* ISC_NET_BSD44MSGHDR */
  	msg->msg_accrights = NULL;
  	msg->msg_accrightslen = 0;
  #endif /* ISC_NET_BSD44MSGHDR */
  
  	if (read_countp != NULL)
  		*read_countp = read_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->peer_address;
  	} else if (sock->type == isc_sockettype_tcp) {
  		INSIST(address == NULL);
  		dev->address = sock->peer_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_UNSET;
  	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) {
  	unsigned int i;
  
  	printf("MSGHDR %p\n", msg);
  	printf("\tname %p, namelen %ld\n", msg->msg_name,
  	       (long) msg->msg_namelen);
  	printf("\tiov %p, iovlen %ld\n", msg->msg_iov,
  	       (long) msg->msg_iovlen);
  	for (i = 0; i < (unsigned int)msg->msg_iovlen; i++)
  		printf("\t\t%d\tbase %p, len %ld\n", i,
  		       msg->msg_iov[i].iov_base,
  		       (long) msg->msg_iov[i].iov_len);
  #ifdef ISC_NET_BSD44MSGHDR
  	printf("\tcontrol %p, controllen %ld\n", msg->msg_control,
  	       (long) msg->msg_controllen);
  #endif
  }
  #endif
  
  #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 */
  
  static int
  doio_recv(isc__socket_t *sock, isc_socketevent_t *dev) {
  	int cc;
  	struct iovec iov[MAXSCATTERGATHER_RECV];
  	size_t read_count;
  	size_t actual_count;
  	struct msghdr msghdr;
  	isc_buffer_t *buffer;
  	int recv_errno;
  	char strbuf[ISC_STRERRORSIZE];
  
  	build_msghdr_recv(sock, dev, &msghdr, iov, &read_count);
  
  #if defined(ISC_SOCKET_DEBUG)
  	dump_msg(&msghdr);
  #endif
  
  	cc = recvmsg(sock->fd, &msghdr, 0);
  	recv_errno = errno;
  
  #if defined(ISC_SOCKET_DEBUG)
  	dump_msg(&msghdr);
  #endif
  
  	if (cc < 0) {
  		if (SOFT_ERROR(recv_errno))
  			return (DOIO_SOFT);
  
  		if (isc_log_wouldlog(isc_lctx, IOEVENT_LEVEL)) {
  			isc__strerror(recv_errno, strbuf, sizeof(strbuf));
  			socket_log(sock, NULL, IOEVENT,
  				   isc_msgcat, ISC_MSGSET_SOCKET,
  				   ISC_MSG_DOIORECV,
  				  "doio_recv: recvmsg(%d) %d bytes, err %d/%s",
  				   sock->fd, cc, recv_errno, strbuf);
  		}
  
  #define SOFT_OR_HARD(_system, _isc) \
  	if (recv_errno == _system) { \
  		if (sock->connected) { \
  			dev->result = _isc; \
  			inc_stats(sock->manager->stats, \
  				  sock->statsindex[STATID_RECVFAIL]); \
  			return (DOIO_HARD); \
  		} \
  		return (DOIO_SOFT); \
  	}
  #define ALWAYS_HARD(_system, _isc) \
  	if (recv_errno == _system) { \
  		dev->result = _isc; \
  		inc_stats(sock->manager->stats, \
  			  sock->statsindex[STATID_RECVFAIL]); \
  		return (DOIO_HARD); \
  	}
  
  		SOFT_OR_HARD(ECONNREFUSED, ISC_R_CONNREFUSED);
  		SOFT_OR_HARD(ENETUNREACH, ISC_R_NETUNREACH);
  		SOFT_OR_HARD(EHOSTUNREACH, ISC_R_HOSTUNREACH);
  		SOFT_OR_HARD(EHOSTDOWN, ISC_R_HOSTDOWN);
  		/* HPUX 11.11 can return EADDRNOTAVAIL. */
  		SOFT_OR_HARD(EADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
  		ALWAYS_HARD(ENOBUFS, ISC_R_NORESOURCES);
  		/* Should never get this one but it was seen. */
  #ifdef ENOPROTOOPT
  		SOFT_OR_HARD(ENOPROTOOPT, ISC_R_HOSTUNREACH);
  #endif
  		/*
  		 * HPUX returns EPROTO and EINVAL on receiving some ICMP/ICMPv6
  		 * errors.
  		 */
  #ifdef EPROTO
  		SOFT_OR_HARD(EPROTO, ISC_R_HOSTUNREACH);
  #endif
  		SOFT_OR_HARD(EINVAL, ISC_R_HOSTUNREACH);
  
  #undef SOFT_OR_HARD
  #undef ALWAYS_HARD
  
  		dev->result = isc__errno2result(recv_errno);
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_RECVFAIL]);
  		return (DOIO_HARD);
  	}
  
  	/*
  	 * On TCP and UNIX sockets, zero length reads indicate EOF,
  	 * while on UDP sockets, zero length reads are perfectly valid,
  	 * although strange.
  	 */
  	switch (sock->type) {
  	case isc_sockettype_tcp:
  	case isc_sockettype_unix:
  		if (cc == 0)
  			return (DOIO_EOF);
  		break;
  	case isc_sockettype_udp:
  		break;
  	case isc_sockettype_fdwatch:
  	default:
  		INSIST(0);
  	}
  
  	if (sock->type == isc_sockettype_udp) {
  		dev->address.length = msghdr.msg_namelen;
  		if (isc_sockaddr_getport(&dev->address) == 0) {
  			if (isc_log_wouldlog(isc_lctx, IOEVENT_LEVEL)) {
  				socket_log(sock, &dev->address, IOEVENT,
  					   isc_msgcat, ISC_MSGSET_SOCKET,
  					   ISC_MSG_ZEROPORT,
  					   "dropping source port zero packet");
  			}
  			return (DOIO_SOFT);
  		}
  		/*
  		 * Simulate a firewall blocking UDP responses bigger than
  		 * 512 bytes.
  		 */
  		if (sock->manager->maxudp != 0 && cc > sock->manager->maxudp)
  			return (DOIO_SOFT);
  	}
  
  	socket_log(sock, &dev->address, IOEVENT,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_PKTRECV,
  		   "packet received correctly");
  
  	/*
  	 * Overflow bit detection.  If we received MORE bytes than we should,
  	 * this indicates an overflow situation.  Set the flag in the
  	 * dev entry and adjust how much we read by one.
  	 */
  #ifdef ISC_NET_RECVOVERFLOW
  	if ((sock->type == isc_sockettype_udp) && ((size_t)cc > read_count)) {
  		dev->attributes |= ISC_SOCKEVENTATTR_TRUNC;
  		cc--;
  	}
  #endif
  
  	/*
  	 * If there are control messages attached, run through them and pull
  	 * out the interesting bits.
  	 */
  	if (sock->type == isc_sockettype_udp)
  		process_cmsg(sock, &msghdr, dev);
  
  	/*
  	 * update the buffers (if any) and the i/o count
  	 */
  	dev->n += cc;
  	actual_count = cc;
  	buffer = ISC_LIST_HEAD(dev->bufferlist);
  	while (buffer != NULL && actual_count > 0U) {
  		REQUIRE(ISC_BUFFER_VALID(buffer));
  		if (isc_buffer_availablelength(buffer) <= actual_count) {
  			actual_count -= isc_buffer_availablelength(buffer);
  			isc_buffer_add(buffer,
  				       isc_buffer_availablelength(buffer));
  		} else {
  			isc_buffer_add(buffer, actual_count);
  			actual_count = 0;
  			POST(actual_count);
  			break;
  		}
  		buffer = ISC_LIST_NEXT(buffer, link);
  		if (buffer == NULL) {
  			INSIST(actual_count == 0U);
  		}
  	}
  
  	/*
  	 * If we read less than we expected, update counters,
  	 * and let the upper layer poke the descriptor.
  	 */
  	if (((size_t)cc != read_count) && (dev->n < dev->minimum))
  		return (DOIO_SOFT);
  
  	/*
  	 * Full reads are posted, or partials if partials are ok.
  	 */
  	dev->result = ISC_R_SUCCESS;
  	return (DOIO_SUCCESS);
  }
  
  /*
   * 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
  doio_send(isc__socket_t *sock, isc_socketevent_t *dev) {
  	int cc;
  	struct iovec iov[MAXSCATTERGATHER_SEND];
  	size_t write_count;
  	struct msghdr msghdr;
  	char addrbuf[ISC_SOCKADDR_FORMATSIZE];
  	int attempts = 0;
  	int send_errno;
  	char strbuf[ISC_STRERRORSIZE];
  
  	build_msghdr_send(sock, dev, &msghdr, iov, &write_count);
  
   resend:
  	cc = sendmsg(sock->fd, &msghdr, 0);
  	send_errno = errno;
  
  	/*
  	 * Check for error or block condition.
  	 */
  	if (cc < 0) {
  		if (send_errno == EINTR && ++attempts < NRETRIES)
  			goto resend;
  
  		if (SOFT_ERROR(send_errno))
  			return (DOIO_SOFT);
  
  #define SOFT_OR_HARD(_system, _isc) \
  	if (send_errno == _system) { \
  		if (sock->connected) { \
  			dev->result = _isc; \
  			inc_stats(sock->manager->stats, \
  				  sock->statsindex[STATID_SENDFAIL]); \
  			return (DOIO_HARD); \
  		} \
  		return (DOIO_SOFT); \
  	}
  #define ALWAYS_HARD(_system, _isc) \
  	if (send_errno == _system) { \
  		dev->result = _isc; \
  		inc_stats(sock->manager->stats, \
  			  sock->statsindex[STATID_SENDFAIL]); \
  		return (DOIO_HARD); \
  	}
  
  		SOFT_OR_HARD(ECONNREFUSED, ISC_R_CONNREFUSED);
  		ALWAYS_HARD(EACCES, ISC_R_NOPERM);
  		ALWAYS_HARD(EAFNOSUPPORT, ISC_R_ADDRNOTAVAIL);
  		ALWAYS_HARD(EADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
  		ALWAYS_HARD(EHOSTUNREACH, ISC_R_HOSTUNREACH);
  #ifdef EHOSTDOWN
  		ALWAYS_HARD(EHOSTDOWN, ISC_R_HOSTUNREACH);
  #endif
  		ALWAYS_HARD(ENETUNREACH, ISC_R_NETUNREACH);
  		ALWAYS_HARD(ENOBUFS, ISC_R_NORESOURCES);
  		ALWAYS_HARD(EPERM, ISC_R_HOSTUNREACH);
  		ALWAYS_HARD(EPIPE, ISC_R_NOTCONNECTED);
  		ALWAYS_HARD(ECONNRESET, ISC_R_CONNECTIONRESET);
  
  #undef SOFT_OR_HARD
  #undef ALWAYS_HARD
  
  		/*
  		 * 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__, "internal_send: %s: %s",
  				 addrbuf, strbuf);
  		dev->result = isc__errno2result(send_errno);
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_SENDFAIL]);
  		return (DOIO_HARD);
  	}
  
  	if (cc == 0) {
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_SENDFAIL]);
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "doio_send: send() %s 0",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_RETURNED, "returned"));
  	}
  
  	/*
  	 * If we write less than we expected, update counters, poke.
  	 */
  	dev->n += cc;
  	if ((size_t)cc != write_count)
  		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);
  }
  
  /*
   * Kill.
   *
   * Caller must ensure that the socket is not locked and no external
   * references exist.
   */
  static void
  closesocket(isc__socketmgr_t *manager, isc__socket_t *sock, int fd) {
  	isc_sockettype_t type = sock->type;
  	int lockid = FDLOCK_ID(fd);
  
  	/*
  	 * No one has this socket open, so the watcher doesn't have to be
  	 * poked, and the socket doesn't have to be locked.
  	 */
  	LOCK(&manager->fdlock[lockid]);
  	manager->fds[fd] = NULL;
  	if (type == isc_sockettype_fdwatch)
  		manager->fdstate[fd] = CLOSED;
  	else
  		manager->fdstate[fd] = CLOSE_PENDING;
  	UNLOCK(&manager->fdlock[lockid]);
  	if (type == isc_sockettype_fdwatch) {
  		/*
  		 * The caller may close the socket once this function returns,
  		 * and `fd' may be reassigned for a new socket.  So we do
  		 * unwatch_fd() here, rather than defer it via select_poke().
  		 * Note: this may complicate data protection among threads and
  		 * may reduce performance due to additional locks.  One way to
  		 * solve this would be to dup() the watched descriptor, but we
  		 * take a simpler approach at this moment.
  		 */
  		(void)unwatch_fd(manager, fd, SELECT_POKE_READ);
  		(void)unwatch_fd(manager, fd, SELECT_POKE_WRITE);
  	} else
  		select_poke(manager, fd, SELECT_POKE_CLOSE);
  
  	inc_stats(manager->stats, sock->statsindex[STATID_CLOSE]);
  
  	/*
  	 * update manager->maxfd here (XXX: this should be implemented more
  	 * efficiently)
  	 */
  #ifdef USE_SELECT
  	LOCK(&manager->lock);
  	if (manager->maxfd == fd) {
  		int i;
  
  		manager->maxfd = 0;
  		for (i = fd - 1; i >= 0; i--) {
  			lockid = FDLOCK_ID(i);
  
  			LOCK(&manager->fdlock[lockid]);
  			if (manager->fdstate[i] == MANAGED) {
  				manager->maxfd = i;
  				UNLOCK(&manager->fdlock[lockid]);
  				break;
  			}
  			UNLOCK(&manager->fdlock[lockid]);
  		}
  #ifdef ISC_PLATFORM_USETHREADS
  		if (manager->maxfd < manager->pipe_fds[0])
  			manager->maxfd = manager->pipe_fds[0];
  #endif
  	}
  	UNLOCK(&manager->lock);
  #endif	/* USE_SELECT */
  }
  
  static void
  destroy(isc__socket_t **sockp) {
  	int fd;
  	isc__socket_t *sock = *sockp;
  	isc__socketmgr_t *manager = sock->manager;
  
  	socket_log(sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
  		   ISC_MSG_DESTROYING, "destroying");
  
  	INSIST(ISC_LIST_EMPTY(sock->accept_list));
  	INSIST(ISC_LIST_EMPTY(sock->recv_list));
  	INSIST(ISC_LIST_EMPTY(sock->send_list));
  	INSIST(sock->connect_ev == NULL);
  	REQUIRE(sock->fd == -1 || sock->fd < (int)manager->maxsocks);
  
  	if (sock->fd >= 0) {
  		fd = sock->fd;
  		sock->fd = -1;
  		closesocket(manager, sock, fd);
  	}
  
  	LOCK(&manager->lock);
  
  	ISC_LIST_UNLINK(manager->socklist, sock, link);
  
  #ifdef USE_WATCHER_THREAD
  	if (ISC_LIST_EMPTY(manager->socklist))
  		SIGNAL(&manager->shutdown_ok);
  #endif /* USE_WATCHER_THREAD */
  
  	/* can't unlock manager as its memory context is still used */
  	free_socket(sockp);
  
  	UNLOCK(&manager->lock);
  }
  
  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;
  	ISC_SOCKADDR_LEN_T cmsgbuflen;
  
  	sock = isc_mem_get(manager->mctx, sizeof(*sock));
  
  	if (sock == NULL)
  		return (ISC_R_NOMEMORY);
  
  	sock->common.magic = 0;
  	sock->common.impmagic = 0;
  	sock->references = 0;
  
  	sock->manager = manager;
  	sock->type = type;
  	sock->fd = -1;
  	sock->dupped = 0;
  	sock->statsindex = NULL;
  
  	ISC_LINK_INIT(sock, link);
  
  	sock->recvcmsgbuf = NULL;
  	sock->sendcmsgbuf = NULL;
  
  	/*
  	 * Set up cmsg buffers.
  	 */
  	cmsgbuflen = 0;
  #if defined(USE_CMSG) && defined(ISC_PLATFORM_HAVEIN6PKTINFO)
  	cmsgbuflen += cmsg_space(sizeof(struct in6_pktinfo));
  #endif
  #if defined(USE_CMSG) && defined(SO_TIMESTAMP)
  	cmsgbuflen += cmsg_space(sizeof(struct timeval));
  #endif
  	sock->recvcmsgbuflen = cmsgbuflen;
  	if (sock->recvcmsgbuflen != 0U) {
  		sock->recvcmsgbuf = isc_mem_get(manager->mctx, cmsgbuflen);
  		if (sock->recvcmsgbuf == NULL) {
  			result = ISC_R_NOMEMORY;
  			goto error;
  		}
  	}
  
  	cmsgbuflen = 0;
  #if defined(USE_CMSG) && defined(ISC_PLATFORM_HAVEIN6PKTINFO)
  	cmsgbuflen += cmsg_space(sizeof(struct in6_pktinfo));
  #if defined(IPV6_USE_MIN_MTU)
  	/*
  	 * Provide space for working around FreeBSD's broken IPV6_USE_MIN_MTU
  	 * support.
  	 */
  	cmsgbuflen += cmsg_space(sizeof(int));
  #endif
  #endif
  	sock->sendcmsgbuflen = cmsgbuflen;
  	if (sock->sendcmsgbuflen != 0U) {
  		sock->sendcmsgbuf = isc_mem_get(manager->mctx, cmsgbuflen);
  		if (sock->sendcmsgbuf == NULL) {
  			result = ISC_R_NOMEMORY;
  			goto error;
  		}
  	}
  
  	memset(sock->name, 0, sizeof(sock->name));
  	sock->tag = NULL;
  
  	/*
  	 * 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_recv = 0;
  	sock->pending_send = 0;
  	sock->pending_accept = 0;
  	sock->listener = 0;
  	sock->connected = 0;
  	sock->connecting = 0;
  	sock->bound = 0;
  
  	/*
  	 * Initialize the lock.
  	 */
  	result = isc_mutex_init(&sock->lock);
  	if (result != ISC_R_SUCCESS) {
  		sock->common.magic = 0;
  		sock->common.impmagic = 0;
  		goto error;
  	}
  
  	/*
  	 * Initialize readable and writable events.
  	 */
  	ISC_EVENT_INIT(&sock->readable_ev, sizeof(intev_t),
  		       ISC_EVENTATTR_NOPURGE, NULL, ISC_SOCKEVENT_INTR,
  		       NULL, sock, sock, NULL, NULL);
  	ISC_EVENT_INIT(&sock->writable_ev, sizeof(intev_t),
  		       ISC_EVENTATTR_NOPURGE, NULL, ISC_SOCKEVENT_INTW,
  		       NULL, sock, sock, NULL, NULL);
  
  	sock->common.magic = ISCAPI_SOCKET_MAGIC;
  	sock->common.impmagic = SOCKET_MAGIC;
  	*socketp = sock;
  
  	return (ISC_R_SUCCESS);
  
   error:
  	if (sock->recvcmsgbuf != NULL)
  		isc_mem_put(manager->mctx, sock->recvcmsgbuf,
  			    sock->recvcmsgbuflen);
  	if (sock->sendcmsgbuf != NULL)
  		isc_mem_put(manager->mctx, sock->sendcmsgbuf,
  			    sock->sendcmsgbuflen);
  	isc_mem_put(manager->mctx, sock, sizeof(*sock));
  
  	return (result);
  }
  
  /*
   * This event requires that the various lists be empty, that the reference
   * count be 1, and that the magic number is valid.  The other socket bits,
   * like the lock, must be initialized as well.  The fd associated must be
   * marked as closed, by setting it to -1 on close, or this routine will
   * also close the socket.
   */
  static void
  free_socket(isc__socket_t **socketp) {
  	isc__socket_t *sock = *socketp;
  
  	INSIST(sock->references == 0);
  	INSIST(VALID_SOCKET(sock));
  	INSIST(!sock->connecting);
  	INSIST(!sock->pending_recv);
  	INSIST(!sock->pending_send);
  	INSIST(!sock->pending_accept);
  	INSIST(ISC_LIST_EMPTY(sock->recv_list));
  	INSIST(ISC_LIST_EMPTY(sock->send_list));
  	INSIST(ISC_LIST_EMPTY(sock->accept_list));
  	INSIST(!ISC_LINK_LINKED(sock, link));
  
  	if (sock->recvcmsgbuf != NULL)
  		isc_mem_put(sock->manager->mctx, sock->recvcmsgbuf,
  			    sock->recvcmsgbuflen);
  	if (sock->sendcmsgbuf != NULL)
  		isc_mem_put(sock->manager->mctx, sock->sendcmsgbuf,
  			    sock->sendcmsgbuflen);
  
  	sock->common.magic = 0;
  	sock->common.impmagic = 0;
  
  	DESTROYLOCK(&sock->lock);
  
  	isc_mem_put(sock->manager->mctx, sock, sizeof(*sock));
  
  	*socketp = NULL;
  }
  
  #ifdef SO_BSDCOMPAT
  /*
   * This really should not be necessary to do.  Having to workout
   * which kernel version we are on at run time so that we don't cause
   * the kernel to issue a warning about us using a deprecated socket option.
   * Such warnings should *never* be on by default in production kernels.
   *
   * We can't do this a build time because executables are moved between
   * machines and hence kernels.
   *
   * We can't just not set SO_BSDCOMAT because some kernels require it.
   */
  
  static isc_once_t         bsdcompat_once = ISC_ONCE_INIT;
  isc_boolean_t bsdcompat = ISC_TRUE;
  
  static void
  clear_bsdcompat(void) {
  #ifdef __linux__
  	 struct utsname buf;
  	 char *endp;
  	 long int major;
  	 long int minor;
  
  	 uname(&buf);    /* Can only fail if buf is bad in Linux. */
  
  	 /* Paranoia in parsing can be increased, but we trust uname(). */
  	 major = strtol(buf.release, &endp, 10);
  	 if (*endp == '.') {
  		minor = strtol(endp+1, &endp, 10);
  		if ((major > 2) || ((major == 2) && (minor >= 4))) {
  			bsdcompat = ISC_FALSE;
  		}
  	 }
  #endif /* __linux __ */
  }
  #endif
  
  static void
  use_min_mtu(isc__socket_t *sock) {
  #if !defined(IPV6_USE_MIN_MTU) && !defined(IPV6_MTU)
  	UNUSED(sock);
  #endif
  #ifdef IPV6_USE_MIN_MTU
  	/* use minimum MTU */
  	if (sock->pf == AF_INET6) {
  		int on = 1;
  		(void)setsockopt(sock->fd, IPPROTO_IPV6, IPV6_USE_MIN_MTU,
  				(void *)&on, sizeof(on));
  	}
  #endif
  #if defined(IPV6_MTU)
  	/*
  	 * Use minimum MTU on IPv6 sockets.
  	 */
  	if (sock->pf == AF_INET6) {
  		int mtu = 1280;
  		(void)setsockopt(sock->fd, IPPROTO_IPV6, IPV6_MTU,
  				 &mtu, sizeof(mtu));
  	}
  #endif
  }
  
  static isc_result_t
  opensocket(isc__socketmgr_t *manager, isc__socket_t *sock,
  	   isc__socket_t *dup_socket)
  {
  	isc_result_t result;
  	char strbuf[ISC_STRERRORSIZE];
  	const char *err = "socket";
  	int tries = 0;
  #if defined(USE_CMSG) || defined(SO_BSDCOMPAT) || defined(SO_NOSIGPIPE)
  	int on = 1;
  #endif
  #if defined(SO_RCVBUF)
  	ISC_SOCKADDR_LEN_T optlen;
  	int size;
  #endif
  
   again:
  	if (dup_socket == NULL) {
  		switch (sock->type) {
  		case isc_sockettype_udp:
  			sock->fd = socket(sock->pf, SOCK_DGRAM, IPPROTO_UDP);
  			break;
  		case isc_sockettype_tcp:
  			sock->fd = socket(sock->pf, SOCK_STREAM, IPPROTO_TCP);
  			break;
  		case isc_sockettype_unix:
  			sock->fd = socket(sock->pf, SOCK_STREAM, 0);
  			break;
  		case isc_sockettype_fdwatch:
  			/*
  			 * We should not be called for isc_sockettype_fdwatch
  			 * sockets.
  			 */
  			INSIST(0);
  			break;
  		}
  	} else {
  		sock->fd = dup(dup_socket->fd);
  		sock->dupped = 1;
  		sock->bound = dup_socket->bound;
  	}
  	if (sock->fd == -1 && errno == EINTR && tries++ < 42)
  		goto again;
  
  #ifdef F_DUPFD
  	/*
  	 * Leave a space for stdio and TCP to work in.
  	 */
  	if (manager->reserved != 0 && sock->type == isc_sockettype_udp &&
  	    sock->fd >= 0 && sock->fd < manager->reserved) {
  		int new, tmp;
  		new = fcntl(sock->fd, F_DUPFD, manager->reserved);
  		tmp = errno;
  		(void)close(sock->fd);
  		errno = tmp;
  		sock->fd = new;
  		err = "isc_socket_create: fcntl/reserved";
  	} else if (sock->fd >= 0 && sock->fd < 20) {
  		int new, tmp;
  		new = fcntl(sock->fd, F_DUPFD, 20);
  		tmp = errno;
  		(void)close(sock->fd);
  		errno = tmp;
  		sock->fd = new;
  		err = "isc_socket_create: fcntl";
  	}
  #endif
  
  	if (sock->fd >= (int)manager->maxsocks) {
  		(void)close(sock->fd);
  		isc_log_iwrite(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			       ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  			       isc_msgcat, ISC_MSGSET_SOCKET,
  			       ISC_MSG_TOOMANYFDS,
  			       "socket: file descriptor exceeds limit (%d/%u)",
  			       sock->fd, manager->maxsocks);
  		return (ISC_R_NORESOURCES);
  	}
  
  	if (sock->fd < 0) {
  		switch (errno) {
  		case EMFILE:
  		case ENFILE:
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			isc_log_iwrite(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				       ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				       isc_msgcat, ISC_MSGSET_SOCKET,
  				       ISC_MSG_TOOMANYFDS,
  				       "%s: %s", err, strbuf);
  			/* fallthrough */
  		case ENOBUFS:
  			return (ISC_R_NORESOURCES);
  
  		case EPROTONOSUPPORT:
  		case EPFNOSUPPORT:
  		case EAFNOSUPPORT:
  		/*
  		 * Linux 2.2 (and maybe others) return EINVAL instead of
  		 * EAFNOSUPPORT.
  		 */
  		case EINVAL:
  			return (ISC_R_FAMILYNOSUPPORT);
  
  		default:
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "%s() %s: %s", err,
  					 isc_msgcat_get(isc_msgcat,
  							ISC_MSGSET_GENERAL,
  							ISC_MSG_FAILED,
  							"failed"),
  					 strbuf);
  			return (ISC_R_UNEXPECTED);
  		}
  	}
  
  	if (dup_socket != NULL)
  		goto setup_done;
  
  	result = make_nonblock(sock->fd);
  	if (result != ISC_R_SUCCESS) {
  		(void)close(sock->fd);
  		return (result);
  	}
  
  #ifdef SO_BSDCOMPAT
  	RUNTIME_CHECK(isc_once_do(&bsdcompat_once,
  				  clear_bsdcompat) == ISC_R_SUCCESS);
  	if (sock->type != isc_sockettype_unix && bsdcompat &&
  	    setsockopt(sock->fd, SOL_SOCKET, SO_BSDCOMPAT,
  		       (void *)&on, sizeof(on)) < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "setsockopt(%d, SO_BSDCOMPAT) %s: %s",
  				 sock->fd,
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		/* Press on... */
  	}
  #endif
  
  #ifdef SO_NOSIGPIPE
  	if (setsockopt(sock->fd, SOL_SOCKET, SO_NOSIGPIPE,
  		       (void *)&on, sizeof(on)) < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "setsockopt(%d, SO_NOSIGPIPE) %s: %s",
  				 sock->fd,
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		/* Press on... */
  	}
  #endif
  
  	/*
  	 * Use minimum mtu if possible.
  	 */
  	use_min_mtu(sock);
  
  #if defined(USE_CMSG) || defined(SO_RCVBUF)
  	if (sock->type == isc_sockettype_udp) {
  
  #if defined(USE_CMSG)
  #if defined(SO_TIMESTAMP)
  		if (setsockopt(sock->fd, SOL_SOCKET, SO_TIMESTAMP,
  			       (void *)&on, sizeof(on)) < 0
  		    && errno != ENOPROTOOPT) {
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "setsockopt(%d, SO_TIMESTAMP) %s: %s",
  					 sock->fd,
  					 isc_msgcat_get(isc_msgcat,
  							ISC_MSGSET_GENERAL,
  							ISC_MSG_FAILED,
  							"failed"),
  					 strbuf);
  			/* Press on... */
  		}
  #endif /* SO_TIMESTAMP */
  
  #if defined(ISC_PLATFORM_HAVEIPV6)
  		if (sock->pf == AF_INET6 && sock->recvcmsgbuflen == 0U) {
  			/*
  			 * Warn explicitly because this anomaly can be hidden
  			 * in usual operation (and unexpectedly appear later).
  			 */
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "No buffer available to receive "
  					 "IPv6 destination");
  		}
  #ifdef ISC_PLATFORM_HAVEIN6PKTINFO
  #ifdef IPV6_RECVPKTINFO
  		/* RFC 3542 */
  		if ((sock->pf == AF_INET6)
  		    && (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_RECVPKTINFO,
  				   (void *)&on, sizeof(on)) < 0)) {
  			isc__strerror(errno, 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
  		/* RFC 2292 */
  		if ((sock->pf == AF_INET6)
  		    && (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_PKTINFO,
  				   (void *)&on, sizeof(on)) < 0)) {
  			isc__strerror(errno, 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 */
  #endif /* ISC_PLATFORM_HAVEIN6PKTINFO */
  #if defined(IPV6_MTU_DISCOVER) && defined(IPV6_PMTUDISC_DONT)
  		/*
  		 * Turn off Path MTU discovery on IPv6/UDP sockets.
  		 */
  		if (sock->pf == AF_INET6) {
  			int action = IPV6_PMTUDISC_DONT;
  			(void)setsockopt(sock->fd, IPPROTO_IPV6,
  					 IPV6_MTU_DISCOVER, &action,
  					 sizeof(action));
  		}
  #endif
  #endif /* ISC_PLATFORM_HAVEIPV6 */
  #endif /* defined(USE_CMSG) */
  
  #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
  		/*
  		 * Turn off Path MTU discovery on IPv4/UDP sockets.
  		 */
  		if (sock->pf == AF_INET) {
  			int action = IP_PMTUDISC_DONT;
  			(void)setsockopt(sock->fd, IPPROTO_IP, IP_MTU_DISCOVER,
  					 &action, sizeof(action));
  		}
  #endif
  #if defined(IP_DONTFRAG)
  		/*
  		 * Turn off Path MTU discovery on IPv4/UDP sockets.
  		 */
  		if (sock->pf == AF_INET) {
  			int off = 0;
  			(void)setsockopt(sock->fd, IPPROTO_IP, IP_DONTFRAG,
  					 &off, sizeof(off));
  		}
  #endif
  
  #if defined(SO_RCVBUF)
  		optlen = sizeof(size);
  		if (getsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
  			       (void *)&size, &optlen) >= 0 &&
  		     size < RCVBUFSIZE) {
  			size = RCVBUFSIZE;
  			if (setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUF,
  				       (void *)&size, sizeof(size)) == -1) {
  				isc__strerror(errno, strbuf, sizeof(strbuf));
  				UNEXPECTED_ERROR(__FILE__, __LINE__,
  					"setsockopt(%d, SO_RCVBUF, %d) %s: %s",
  					sock->fd, size,
  					isc_msgcat_get(isc_msgcat,
  						       ISC_MSGSET_GENERAL,
  						       ISC_MSG_FAILED,
  						       "failed"),
  					strbuf);
  			}
  		}
  #endif
  	}
  #endif /* defined(USE_CMSG) || defined(SO_RCVBUF) */
  
  setup_done:
  	inc_stats(manager->stats, sock->statsindex[STATID_OPEN]);
  
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * Create a 'type' socket or duplicate an existing 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'.
   */
  static isc_result_t
  socket_create(isc_socketmgr_t *manager0, int pf, isc_sockettype_t type,
  	      isc_socket_t **socketp, isc_socket_t *dup_socket)
  {
  	isc__socket_t *sock = NULL;
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  	isc_result_t result;
  	int lockid;
  
  	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);
  
  	switch (sock->type) {
  	case isc_sockettype_udp:
  		sock->statsindex =
  			(pf == AF_INET) ? udp4statsindex : udp6statsindex;
  		break;
  	case isc_sockettype_tcp:
  		sock->statsindex =
  			(pf == AF_INET) ? tcp4statsindex : tcp6statsindex;
  		break;
  	case isc_sockettype_unix:
  		sock->statsindex = unixstatsindex;
  		break;
  	default:
  		INSIST(0);
  	}
  
  	sock->pf = pf;
  
  	result = opensocket(manager, sock, (isc__socket_t *)dup_socket);
  	if (result != ISC_R_SUCCESS) {
  		inc_stats(manager->stats, sock->statsindex[STATID_OPENFAIL]);
  		free_socket(&sock);
  		return (result);
  	}
  
  	sock->common.methods = (isc_socketmethods_t *)&socketmethods;
  	sock->references = 1;
  	*socketp = (isc_socket_t *)sock;
  
  	/*
  	 * Note we don't have to lock the socket like we normally would because
  	 * there are no external references to it yet.
  	 */
  
  	lockid = FDLOCK_ID(sock->fd);
  	LOCK(&manager->fdlock[lockid]);
  	manager->fds[sock->fd] = sock;
  	manager->fdstate[sock->fd] = MANAGED;
  #ifdef USE_DEVPOLL
  	INSIST(sock->manager->fdpollinfo[sock->fd].want_read == 0 &&
  	       sock->manager->fdpollinfo[sock->fd].want_write == 0);
  #endif
  	UNLOCK(&manager->fdlock[lockid]);
  
  	LOCK(&manager->lock);
  	ISC_LIST_APPEND(manager->socklist, sock, link);
  #ifdef USE_SELECT
  	if (manager->maxfd < sock->fd)
  		manager->maxfd = sock->fd;
  #endif
  	UNLOCK(&manager->lock);
  
  	socket_log(sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
  		   ISC_MSG_CREATED, dup_socket != NULL ? "dupped" : "created");
  
  	return (ISC_R_SUCCESS);
  }
  
  /*%
   * 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_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_create(isc_socketmgr_t *manager0, int pf, isc_sockettype_t type,
  		   isc_socket_t **socketp)
  {
  	return (socket_create(manager0, pf, type, socketp, NULL));
  }
  
  /*%
   * Duplicate an existing socket.  The new socket is returned
   * in 'socketp'.
   */
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_dup(isc_socket_t *sock0, isc_socket_t **socketp) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(sock));
  	REQUIRE(socketp != NULL && *socketp == NULL);
  
  	return (socket_create((isc_socketmgr_t *) sock->manager,
  			      sock->pf, sock->type, socketp,
  			      sock0));
  }
  
  #ifdef BIND9
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_open(isc_socket_t *sock0) {
  	isc_result_t result;
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	REQUIRE(sock->references == 1);
  	REQUIRE(sock->type != isc_sockettype_fdwatch);
  	UNLOCK(&sock->lock);
  	/*
  	 * We don't need to retain the lock hereafter, since no one else has
  	 * this socket.
  	 */
  	REQUIRE(sock->fd == -1);
  
  	result = opensocket(sock->manager, sock, NULL);
  	if (result != ISC_R_SUCCESS)
  		sock->fd = -1;
  
  	if (result == ISC_R_SUCCESS) {
  		int lockid = FDLOCK_ID(sock->fd);
  
  		LOCK(&sock->manager->fdlock[lockid]);
  		sock->manager->fds[sock->fd] = sock;
  		sock->manager->fdstate[sock->fd] = MANAGED;
  #ifdef USE_DEVPOLL
  		INSIST(sock->manager->fdpollinfo[sock->fd].want_read == 0 &&
  		       sock->manager->fdpollinfo[sock->fd].want_write == 0);
  #endif
  		UNLOCK(&sock->manager->fdlock[lockid]);
  
  #ifdef USE_SELECT
  		LOCK(&sock->manager->lock);
  		if (sock->manager->maxfd < sock->fd)
  			sock->manager->maxfd = sock->fd;
  		UNLOCK(&sock->manager->lock);
  #endif
  	}
  
  	return (result);
  }
  #endif	/* BIND9 */
  
  /*
   * 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_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_fdwatchcreate(isc_socketmgr_t *manager0, int fd, int flags,
  			  isc_sockfdwatch_t callback, void *cbarg,
  			  isc_task_t *task, isc_socket_t **socketp)
  {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  	isc__socket_t *sock = NULL;
  	isc_result_t result;
  	int lockid;
  
  	REQUIRE(VALID_MANAGER(manager));
  	REQUIRE(socketp != NULL && *socketp == NULL);
  
  	result = allocate_socket(manager, isc_sockettype_fdwatch, &sock);
  	if (result != ISC_R_SUCCESS)
  		return (result);
  
  	sock->fd = fd;
  	sock->fdwatcharg = cbarg;
  	sock->fdwatchcb = callback;
  	sock->fdwatchflags = flags;
  	sock->fdwatchtask = task;
  	sock->statsindex = fdwatchstatsindex;
  
  	sock->common.methods = (isc_socketmethods_t *)&socketmethods;
  	sock->references = 1;
  	*socketp = (isc_socket_t *)sock;
  
  	/*
  	 * Note we don't have to lock the socket like we normally would because
  	 * there are no external references to it yet.
  	 */
  
  	lockid = FDLOCK_ID(sock->fd);
  	LOCK(&manager->fdlock[lockid]);
  	manager->fds[sock->fd] = sock;
  	manager->fdstate[sock->fd] = MANAGED;
  	UNLOCK(&manager->fdlock[lockid]);
  
  	LOCK(&manager->lock);
  	ISC_LIST_APPEND(manager->socklist, sock, link);
  #ifdef USE_SELECT
  	if (manager->maxfd < sock->fd)
  		manager->maxfd = sock->fd;
  #endif
  	UNLOCK(&manager->lock);
  
  	if (flags & ISC_SOCKFDWATCH_READ)
  		select_poke(sock->manager, sock->fd, SELECT_POKE_READ);
  	if (flags & ISC_SOCKFDWATCH_WRITE)
  		select_poke(sock->manager, sock->fd, SELECT_POKE_WRITE);
  
  	socket_log(sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
  		   ISC_MSG_CREATED, "fdwatch-created");
  
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * Indicate to the manager that it should watch the socket again.
   * This can be used to restart watching if the previous event handler
   * didn't indicate there was more data to be processed.  Primarily
   * it is for writing but could be used for reading if desired
   */
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_fdwatchpoke(isc_socket_t *sock0, int flags)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	/*
  	 * We check both flags first to allow us to get the lock
  	 * once but only if we need it.
  	 */
  
  	if ((flags & (ISC_SOCKFDWATCH_READ | ISC_SOCKFDWATCH_WRITE)) != 0) {
  		LOCK(&sock->lock);
  		if (((flags & ISC_SOCKFDWATCH_READ) != 0) &&
  		    !sock->pending_recv)
  			select_poke(sock->manager, sock->fd,
  				    SELECT_POKE_READ);
  		if (((flags & ISC_SOCKFDWATCH_WRITE) != 0) &&
  		    !sock->pending_send)
  			select_poke(sock->manager, sock->fd,
  				    SELECT_POKE_WRITE);
  		UNLOCK(&sock->lock);
  	}
  
  	socket_log(sock, NULL, TRACE, isc_msgcat, ISC_MSGSET_SOCKET,
  		   ISC_MSG_POKED, "fdwatch-poked flags: %d", flags);
  
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * Attach to a socket.  Caller must explicitly detach when it is done.
   */
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_attach(isc_socket_t *sock0, isc_socket_t **socketp) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(sock));
  	REQUIRE(socketp != NULL && *socketp == NULL);
  
  	LOCK(&sock->lock);
  	sock->references++;
  	UNLOCK(&sock->lock);
  
  	*socketp = (isc_socket_t *)sock;
  }
  
  /*
   * Dereference a socket.  If this is the last reference to it, clean things
   * up by destroying the socket.
   */
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_detach(isc_socket_t **socketp) {
  	isc__socket_t *sock;
  	isc_boolean_t kill_socket = ISC_FALSE;
  
  	REQUIRE(socketp != NULL);
  	sock = (isc__socket_t *)*socketp;
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	REQUIRE(sock->references > 0);
  	sock->references--;
  	if (sock->references == 0)
  		kill_socket = ISC_TRUE;
  	UNLOCK(&sock->lock);
  
  	if (kill_socket)
  		destroy(&sock);
  
  	*socketp = NULL;
  }
  
  #ifdef BIND9
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_close(isc_socket_t *sock0) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	int fd;
  	isc__socketmgr_t *manager;
  
  	fflush(stdout);
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  
  	REQUIRE(sock->references == 1);
  	REQUIRE(sock->type != isc_sockettype_fdwatch);
  	REQUIRE(sock->fd >= 0 && sock->fd < (int)sock->manager->maxsocks);
  
  	INSIST(!sock->connecting);
  	INSIST(!sock->pending_recv);
  	INSIST(!sock->pending_send);
  	INSIST(!sock->pending_accept);
  	INSIST(ISC_LIST_EMPTY(sock->recv_list));
  	INSIST(ISC_LIST_EMPTY(sock->send_list));
  	INSIST(ISC_LIST_EMPTY(sock->accept_list));
  	INSIST(sock->connect_ev == NULL);
  
  	manager = sock->manager;
  	fd = sock->fd;
  	sock->fd = -1;
  	sock->dupped = 0;
  	memset(sock->name, 0, sizeof(sock->name));
  	sock->tag = NULL;
  	sock->listener = 0;
  	sock->connected = 0;
  	sock->connecting = 0;
  	sock->bound = 0;
  	isc_sockaddr_any(&sock->peer_address);
  
  	UNLOCK(&sock->lock);
  
  	closesocket(manager, sock, fd);
  
  	return (ISC_R_SUCCESS);
  }
  #endif	/* BIND9 */
  
  /*
   * I/O is possible on a given socket.  Schedule an event to this task that
   * will call an internal function to do the I/O.  This will charge the
   * task with the I/O operation and let our select loop handler get back
   * to doing something real as fast as possible.
   *
   * The socket and manager must be locked before calling this function.
   */
  static void
  dispatch_recv(isc__socket_t *sock) {
  	intev_t *iev;
  	isc_socketevent_t *ev;
  	isc_task_t *sender;
  
  	INSIST(!sock->pending_recv);
  
  	if (sock->type != isc_sockettype_fdwatch) {
  		ev = ISC_LIST_HEAD(sock->recv_list);
  		if (ev == NULL)
  			return;
  		socket_log(sock, NULL, EVENT, NULL, 0, 0,
  			   "dispatch_recv:  event %p -> task %p",
  			   ev, ev->ev_sender);
  		sender = ev->ev_sender;
  	} else {
  		sender = sock->fdwatchtask;
  	}
  
  	sock->pending_recv = 1;
  	iev = &sock->readable_ev;
  
  	sock->references++;
  	iev->ev_sender = sock;
  	if (sock->type == isc_sockettype_fdwatch)
  		iev->ev_action = internal_fdwatch_read;
  	else
  		iev->ev_action = internal_recv;
  	iev->ev_arg = sock;
  
  	isc_task_send(sender, (isc_event_t **)&iev);
  }
  
  static void
  dispatch_send(isc__socket_t *sock) {
  	intev_t *iev;
  	isc_socketevent_t *ev;
  	isc_task_t *sender;
  
  	INSIST(!sock->pending_send);
  
  	if (sock->type != isc_sockettype_fdwatch) {
  		ev = ISC_LIST_HEAD(sock->send_list);
  		if (ev == NULL)
  			return;
  		socket_log(sock, NULL, EVENT, NULL, 0, 0,
  			   "dispatch_send:  event %p -> task %p",
  			   ev, ev->ev_sender);
  		sender = ev->ev_sender;
  	} else {
  		sender = sock->fdwatchtask;
  	}
  
  	sock->pending_send = 1;
  	iev = &sock->writable_ev;
  
  	sock->references++;
  	iev->ev_sender = sock;
  	if (sock->type == isc_sockettype_fdwatch)
  		iev->ev_action = internal_fdwatch_write;
  	else
  		iev->ev_action = internal_send;
  	iev->ev_arg = sock;
  
  	isc_task_send(sender, (isc_event_t **)&iev);
  }
  
  /*
   * Dispatch an internal accept event.
   */
  static void
  dispatch_accept(isc__socket_t *sock) {
  	intev_t *iev;
  	isc_socket_newconnev_t *ev;
  
  	INSIST(!sock->pending_accept);
  
  	/*
  	 * Are there any done events left, or were they all canceled
  	 * before the manager got the socket lock?
  	 */
  	ev = ISC_LIST_HEAD(sock->accept_list);
  	if (ev == NULL)
  		return;
  
  	sock->pending_accept = 1;
  	iev = &sock->readable_ev;
  
  	sock->references++;  /* keep socket around for this internal event */
  	iev->ev_sender = sock;
  	iev->ev_action = internal_accept;
  	iev->ev_arg = sock;
  
  	isc_task_send(ev->ev_sender, (isc_event_t **)&iev);
  }
  
  static void
  dispatch_connect(isc__socket_t *sock) {
  	intev_t *iev;
  	isc_socket_connev_t *ev;
  
  	iev = &sock->writable_ev;
  
  	ev = sock->connect_ev;
  	INSIST(ev != NULL); /* XXX */
  
  	INSIST(sock->connecting);
  
  	sock->references++;  /* keep socket around for this internal event */
  	iev->ev_sender = sock;
  	iev->ev_action = internal_connect;
  	iev->ev_arg = sock;
  
  	isc_task_send(ev->ev_sender, (isc_event_t **)&iev);
  }
  
  /*
   * 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 socket 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);
  }
  
  /*
   * See comments for send_recvdone_event() above.
   *
   * Caller must have the socket locked if the event is attached to the socket.
   */
  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);
  }
  
  /*
   * Call accept() on a socket, to get the new file descriptor.  The listen
   * socket is used as a prototype to create a new isc_socket_t.  The new
   * socket has one outstanding reference.  The task receiving the event
   * will be detached from just after the event is delivered.
   *
   * 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 unlock and return.
   */
  static void
  internal_accept(isc_task_t *me, isc_event_t *ev) {
  	isc__socket_t *sock;
  	isc__socketmgr_t *manager;
  	isc_socket_newconnev_t *dev;
  	isc_task_t *task;
  	ISC_SOCKADDR_LEN_T addrlen;
  	int fd;
  	isc_result_t result = ISC_R_SUCCESS;
  	char strbuf[ISC_STRERRORSIZE];
  	const char *err = "accept";
  
  	UNUSED(me);
  
  	sock = ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	socket_log(sock, NULL, TRACE,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTLOCK,
  		   "internal_accept called, locked socket");
  
  	manager = sock->manager;
  	INSIST(VALID_MANAGER(manager));
  
  	INSIST(sock->listener);
  	INSIST(sock->pending_accept == 1);
  	sock->pending_accept = 0;
  
  	INSIST(sock->references > 0);
  	sock->references--;  /* the internal event is done with this socket */
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	/*
  	 * Get the first item off the accept list.
  	 * If it is empty, unlock the socket and return.
  	 */
  	dev = ISC_LIST_HEAD(sock->accept_list);
  	if (dev == NULL) {
  		UNLOCK(&sock->lock);
  		return;
  	}
  
  	/*
  	 * Try to accept the new connection.  If the accept fails with
  	 * EAGAIN or EINTR, simply poke the watcher to watch this socket
  	 * again.  Also ignore ECONNRESET, which has been reported to
  	 * be spuriously returned on Linux 2.2.19 although it is not
  	 * a documented error for accept().  ECONNABORTED has been
  	 * reported for Solaris 8.  The rest are thrown in not because
  	 * we have seen them but because they are ignored by other
  	 * daemons such as BIND 8 and Apache.
  	 */
  
  	addrlen = sizeof(NEWCONNSOCK(dev)->peer_address.type);
  	memset(&NEWCONNSOCK(dev)->peer_address.type, 0, addrlen);
  	fd = accept(sock->fd, &NEWCONNSOCK(dev)->peer_address.type.sa,
  		    (void *)&addrlen);
  
  #ifdef F_DUPFD
  	/*
  	 * Leave a space for stdio to work in.
  	 */
  	if (fd >= 0 && fd < 20) {
  		int new, tmp;
  		new = fcntl(fd, F_DUPFD, 20);
  		tmp = errno;
  		(void)close(fd);
  		errno = tmp;
  		fd = new;
  		err = "accept/fcntl";
  	}
  #endif
  
  	if (fd < 0) {
  		if (SOFT_ERROR(errno))
  			goto soft_error;
  		switch (errno) {
  		case ENFILE:
  		case EMFILE:
  			isc_log_iwrite(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				       ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				       isc_msgcat, ISC_MSGSET_SOCKET,
  				       ISC_MSG_TOOMANYFDS,
  				       "%s: too many open file descriptors",
  				       err);
  			goto soft_error;
  
  		case ENOBUFS:
  		case ENOMEM:
  		case ECONNRESET:
  		case ECONNABORTED:
  		case EHOSTUNREACH:
  		case EHOSTDOWN:
  		case ENETUNREACH:
  		case ENETDOWN:
  		case ECONNREFUSED:
  #ifdef EPROTO
  		case EPROTO:
  #endif
  #ifdef ENONET
  		case ENONET:
  #endif
  			goto soft_error;
  		default:
  			break;
  		}
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "internal_accept: %s() %s: %s", err,
  				 isc_msgcat_get(isc_msgcat,
  						ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED,
  						"failed"),
  				 strbuf);
  		fd = -1;
  		result = ISC_R_UNEXPECTED;
  	} else {
  		if (addrlen == 0U) {
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "internal_accept(): "
  					 "accept() failed to return "
  					 "remote address");
  
  			(void)close(fd);
  			goto soft_error;
  		} else if (NEWCONNSOCK(dev)->peer_address.type.sa.sa_family !=
  			   sock->pf)
  		{
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "internal_accept(): "
  					 "accept() returned peer address "
  					 "family %u (expected %u)",
  					 NEWCONNSOCK(dev)->peer_address.
  					 type.sa.sa_family,
  					 sock->pf);
  			(void)close(fd);
  			goto soft_error;
  		} else if (fd >= (int)manager->maxsocks) {
  			isc_log_iwrite(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				       ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				       isc_msgcat, ISC_MSGSET_SOCKET,
  				       ISC_MSG_TOOMANYFDS,
  				       "accept: "
  				       "file descriptor exceeds limit (%d/%u)",
  				       fd, manager->maxsocks);
  			(void)close(fd);
  			goto soft_error;
  		}
  	}
  
  	if (fd != -1) {
  		NEWCONNSOCK(dev)->peer_address.length = addrlen;
  		NEWCONNSOCK(dev)->pf = sock->pf;
  	}
  
  	/*
  	 * Pull off the done event.
  	 */
  	ISC_LIST_UNLINK(sock->accept_list, dev, ev_link);
  
  	/*
  	 * Poke watcher if there are more pending accepts.
  	 */
  	if (!ISC_LIST_EMPTY(sock->accept_list))
  		select_poke(sock->manager, sock->fd, SELECT_POKE_ACCEPT);
  
  	UNLOCK(&sock->lock);
  
  	if (fd != -1) {
  		result = make_nonblock(fd);
  		if (result != ISC_R_SUCCESS) {
  			(void)close(fd);
  			fd = -1;
  		}
  	}
  
  	/*
  	 * -1 means the new socket didn't happen.
  	 */
  	if (fd != -1) {
  		int lockid = FDLOCK_ID(fd);
  
  		NEWCONNSOCK(dev)->fd = fd;
  		NEWCONNSOCK(dev)->bound = 1;
  		NEWCONNSOCK(dev)->connected = 1;
  
  		/*
  		 * Use minimum mtu if possible.
  		 */
  		use_min_mtu(NEWCONNSOCK(dev));
  
  		/*
  		 * Save away the remote address
  		 */
  		dev->address = NEWCONNSOCK(dev)->peer_address;
  
  		LOCK(&manager->fdlock[lockid]);
  		manager->fds[fd] = NEWCONNSOCK(dev);
  		manager->fdstate[fd] = MANAGED;
  		UNLOCK(&manager->fdlock[lockid]);
  
  		LOCK(&manager->lock);
  
  #ifdef USE_SELECT
  		if (manager->maxfd < fd)
  			manager->maxfd = fd;
  #endif
  
  		socket_log(sock, &NEWCONNSOCK(dev)->peer_address, CREATION,
  			   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_ACCEPTEDCXN,
  			   "accepted connection, new socket %p",
  			   dev->newsocket);
  
  		ISC_LIST_APPEND(manager->socklist, NEWCONNSOCK(dev), link);
  
  		UNLOCK(&manager->lock);
  
  		inc_stats(manager->stats, sock->statsindex[STATID_ACCEPT]);
  	} else {
  		inc_stats(manager->stats, sock->statsindex[STATID_ACCEPTFAIL]);
  		NEWCONNSOCK(dev)->references--;
  		free_socket((isc__socket_t **)&dev->newsocket);
  	}
  
  	/*
  	 * Fill in the done event details and send it off.
  	 */
  	dev->result = result;
  	task = dev->ev_sender;
  	dev->ev_sender = sock;
  
  	isc_task_sendanddetach(&task, ISC_EVENT_PTR(&dev));
  	return;
  
   soft_error:
  	select_poke(sock->manager, sock->fd, SELECT_POKE_ACCEPT);
  	UNLOCK(&sock->lock);
  
  	inc_stats(manager->stats, sock->statsindex[STATID_ACCEPTFAIL]);
  	return;
  }
  
  static void
  internal_recv(isc_task_t *me, isc_event_t *ev) {
  	isc_socketevent_t *dev;
  	isc__socket_t *sock;
  
  	INSIST(ev->ev_type == ISC_SOCKEVENT_INTR);
  
  	sock = ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	socket_log(sock, NULL, IOEVENT,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALRECV,
  		   "internal_recv: task %p got event %p", me, ev);
  
  	INSIST(sock->pending_recv == 1);
  	sock->pending_recv = 0;
  
  	INSIST(sock->references > 0);
  	sock->references--;  /* the internal event is done with this socket */
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	/*
  	 * Try to do as much I/O as possible on this socket.  There are no
  	 * limits here, currently.
  	 */
  	dev = ISC_LIST_HEAD(sock->recv_list);
  	while (dev != NULL) {
  		switch (doio_recv(sock, dev)) {
  		case DOIO_SOFT:
  			goto poke;
  
  		case DOIO_EOF:
  			/*
  			 * read of 0 means the remote end was closed.
  			 * Run through the event queue and dispatch all
  			 * the events with an EOF result code.
  			 */
  			do {
  				dev->result = ISC_R_EOF;
  				send_recvdone_event(sock, &dev);
  				dev = ISC_LIST_HEAD(sock->recv_list);
  			} while (dev != NULL);
  			goto poke;
  
  		case DOIO_SUCCESS:
  		case DOIO_HARD:
  			send_recvdone_event(sock, &dev);
  			break;
  		}
  
  		dev = ISC_LIST_HEAD(sock->recv_list);
  	}
  
   poke:
  	if (!ISC_LIST_EMPTY(sock->recv_list))
  		select_poke(sock->manager, sock->fd, SELECT_POKE_READ);
  
  	UNLOCK(&sock->lock);
  }
  
  static void
  internal_send(isc_task_t *me, isc_event_t *ev) {
  	isc_socketevent_t *dev;
  	isc__socket_t *sock;
  
  	INSIST(ev->ev_type == ISC_SOCKEVENT_INTW);
  
  	/*
  	 * Find out what socket this is and lock it.
  	 */
  	sock = (isc__socket_t *)ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	socket_log(sock, NULL, IOEVENT,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALSEND,
  		   "internal_send: task %p got event %p", me, ev);
  
  	INSIST(sock->pending_send == 1);
  	sock->pending_send = 0;
  
  	INSIST(sock->references > 0);
  	sock->references--;  /* the internal event is done with this socket */
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	/*
  	 * Try to do as much I/O as possible on this socket.  There are no
  	 * limits here, currently.
  	 */
  	dev = ISC_LIST_HEAD(sock->send_list);
  	while (dev != NULL) {
  		switch (doio_send(sock, dev)) {
  		case DOIO_SOFT:
  			goto poke;
  
  		case DOIO_HARD:
  		case DOIO_SUCCESS:
  			send_senddone_event(sock, &dev);
  			break;
  		}
  
  		dev = ISC_LIST_HEAD(sock->send_list);
  	}
  
   poke:
  	if (!ISC_LIST_EMPTY(sock->send_list))
  		select_poke(sock->manager, sock->fd, SELECT_POKE_WRITE);
  
  	UNLOCK(&sock->lock);
  }
  
  static void
  internal_fdwatch_write(isc_task_t *me, isc_event_t *ev) {
  	isc__socket_t *sock;
  	int more_data;
  
  	INSIST(ev->ev_type == ISC_SOCKEVENT_INTW);
  
  	/*
  	 * Find out what socket this is and lock it.
  	 */
  	sock = (isc__socket_t *)ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	socket_log(sock, NULL, IOEVENT,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALSEND,
  		   "internal_fdwatch_write: task %p got event %p", me, ev);
  
  	INSIST(sock->pending_send == 1);
  
  	UNLOCK(&sock->lock);
  	more_data = (sock->fdwatchcb)(me, (isc_socket_t *)sock,
  				      sock->fdwatcharg, ISC_SOCKFDWATCH_WRITE);
  	LOCK(&sock->lock);
  
  	sock->pending_send = 0;
  
  	INSIST(sock->references > 0);
  	sock->references--;  /* the internal event is done with this socket */
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	if (more_data)
  		select_poke(sock->manager, sock->fd, SELECT_POKE_WRITE);
  
  	UNLOCK(&sock->lock);
  }
  
  static void
  internal_fdwatch_read(isc_task_t *me, isc_event_t *ev) {
  	isc__socket_t *sock;
  	int more_data;
  
  	INSIST(ev->ev_type == ISC_SOCKEVENT_INTR);
  
  	/*
  	 * Find out what socket this is and lock it.
  	 */
  	sock = (isc__socket_t *)ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	socket_log(sock, NULL, IOEVENT,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_INTERNALRECV,
  		   "internal_fdwatch_read: task %p got event %p", me, ev);
  
  	INSIST(sock->pending_recv == 1);
  
  	UNLOCK(&sock->lock);
  	more_data = (sock->fdwatchcb)(me, (isc_socket_t *)sock,
  				      sock->fdwatcharg, ISC_SOCKFDWATCH_READ);
  	LOCK(&sock->lock);
  
  	sock->pending_recv = 0;
  
  	INSIST(sock->references > 0);
  	sock->references--;  /* the internal event is done with this socket */
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	if (more_data)
  		select_poke(sock->manager, sock->fd, SELECT_POKE_READ);
  
  	UNLOCK(&sock->lock);
  }
  
  /*
   * Process read/writes on each fd here.  Avoid locking
   * and unlocking twice if both reads and writes are possible.
   */
  static void
  process_fd(isc__socketmgr_t *manager, int fd, isc_boolean_t readable,
  	   isc_boolean_t writeable)
  {
  	isc__socket_t *sock;
  	isc_boolean_t unlock_sock;
  	isc_boolean_t unwatch_read = ISC_FALSE, unwatch_write = ISC_FALSE;
  	int lockid = FDLOCK_ID(fd);
  
  	/*
  	 * If the socket is going to be closed, don't do more I/O.
  	 */
  	LOCK(&manager->fdlock[lockid]);
  	if (manager->fdstate[fd] == CLOSE_PENDING) {
  		UNLOCK(&manager->fdlock[lockid]);
  
  		(void)unwatch_fd(manager, fd, SELECT_POKE_READ);
  		(void)unwatch_fd(manager, fd, SELECT_POKE_WRITE);
  		return;
  	}
  
  	sock = manager->fds[fd];
  	unlock_sock = ISC_FALSE;
  	if (readable) {
  		if (sock == NULL) {
  			unwatch_read = ISC_TRUE;
  			goto check_write;
  		}
  		unlock_sock = ISC_TRUE;
  		LOCK(&sock->lock);
  		if (!SOCK_DEAD(sock)) {
  			if (sock->listener)
  				dispatch_accept(sock);
  			else
  				dispatch_recv(sock);
  		}
  		unwatch_read = ISC_TRUE;
  	}
  check_write:
  	if (writeable) {
  		if (sock == NULL) {
  			unwatch_write = ISC_TRUE;
  			goto unlock_fd;
  		}
  		if (!unlock_sock) {
  			unlock_sock = ISC_TRUE;
  			LOCK(&sock->lock);
  		}
  		if (!SOCK_DEAD(sock)) {
  			if (sock->connecting)
  				dispatch_connect(sock);
  			else
  				dispatch_send(sock);
  		}
  		unwatch_write = ISC_TRUE;
  	}
  	if (unlock_sock)
  		UNLOCK(&sock->lock);
  
   unlock_fd:
  	UNLOCK(&manager->fdlock[lockid]);
  	if (unwatch_read)
  		(void)unwatch_fd(manager, fd, SELECT_POKE_READ);
  	if (unwatch_write)
  		(void)unwatch_fd(manager, fd, SELECT_POKE_WRITE);
  
  }
  
  #ifdef USE_KQUEUE
  static isc_boolean_t
  process_fds(isc__socketmgr_t *manager, struct kevent *events, int nevents) {
  	int i;
  	isc_boolean_t readable, writable;
  	isc_boolean_t done = ISC_FALSE;
  #ifdef USE_WATCHER_THREAD
  	isc_boolean_t have_ctlevent = ISC_FALSE;
  #endif
  
  	if (nevents == manager->nevents) {
  		/*
  		 * This is not an error, but something unexpected.  If this
  		 * happens, it may indicate the need for increasing
  		 * ISC_SOCKET_MAXEVENTS.
  		 */
  		manager_log(manager, ISC_LOGCATEGORY_GENERAL,
  			    ISC_LOGMODULE_SOCKET, ISC_LOG_INFO,
  			    "maximum number of FD events (%d) received",
  			    nevents);
  	}
  
  	for (i = 0; i < nevents; i++) {
  		REQUIRE(events[i].ident < manager->maxsocks);
  #ifdef USE_WATCHER_THREAD
  		if (events[i].ident == (uintptr_t)manager->pipe_fds[0]) {
  			have_ctlevent = ISC_TRUE;
  			continue;
  		}
  #endif
  		readable = ISC_TF(events[i].filter == EVFILT_READ);
  		writable = ISC_TF(events[i].filter == EVFILT_WRITE);
  		process_fd(manager, events[i].ident, readable, writable);
  	}
  
  #ifdef USE_WATCHER_THREAD
  	if (have_ctlevent)
  		done = process_ctlfd(manager);
  #endif
  
  	return (done);
  }
  #elif defined(USE_EPOLL)
  static isc_boolean_t
  process_fds(isc__socketmgr_t *manager, struct epoll_event *events, int nevents)
  {
  	int i;
  	isc_boolean_t done = ISC_FALSE;
  #ifdef USE_WATCHER_THREAD
  	isc_boolean_t have_ctlevent = ISC_FALSE;
  #endif
  
  	if (nevents == manager->nevents) {
  		manager_log(manager, ISC_LOGCATEGORY_GENERAL,
  			    ISC_LOGMODULE_SOCKET, ISC_LOG_INFO,
  			    "maximum number of FD events (%d) received",
  			    nevents);
  	}
  
  	for (i = 0; i < nevents; i++) {
  		REQUIRE(events[i].data.fd < (int)manager->maxsocks);
  #ifdef USE_WATCHER_THREAD
  		if (events[i].data.fd == manager->pipe_fds[0]) {
  			have_ctlevent = ISC_TRUE;
  			continue;
  		}
  #endif
  		if ((events[i].events & EPOLLERR) != 0 ||
  		    (events[i].events & EPOLLHUP) != 0) {
  			/*
  			 * epoll does not set IN/OUT bits on an erroneous
  			 * condition, so we need to try both anyway.  This is a
  			 * bit inefficient, but should be okay for such rare
  			 * events.  Note also that the read or write attempt
  			 * won't block because we use non-blocking sockets.
  			 */
  			events[i].events |= (EPOLLIN | EPOLLOUT);
  		}
  		process_fd(manager, events[i].data.fd,
  			   (events[i].events & EPOLLIN) != 0,
  			   (events[i].events & EPOLLOUT) != 0);
  	}
  
  #ifdef USE_WATCHER_THREAD
  	if (have_ctlevent)
  		done = process_ctlfd(manager);
  #endif
  
  	return (done);
  }
  #elif defined(USE_DEVPOLL)
  static isc_boolean_t
  process_fds(isc__socketmgr_t *manager, struct pollfd *events, int nevents) {
  	int i;
  	isc_boolean_t done = ISC_FALSE;
  #ifdef USE_WATCHER_THREAD
  	isc_boolean_t have_ctlevent = ISC_FALSE;
  #endif
  
  	if (nevents == manager->nevents) {
  		manager_log(manager, ISC_LOGCATEGORY_GENERAL,
  			    ISC_LOGMODULE_SOCKET, ISC_LOG_INFO,
  			    "maximum number of FD events (%d) received",
  			    nevents);
  	}
  
  	for (i = 0; i < nevents; i++) {
  		REQUIRE(events[i].fd < (int)manager->maxsocks);
  #ifdef USE_WATCHER_THREAD
  		if (events[i].fd == manager->pipe_fds[0]) {
  			have_ctlevent = ISC_TRUE;
  			continue;
  		}
  #endif
  		process_fd(manager, events[i].fd,
  			   (events[i].events & POLLIN) != 0,
  			   (events[i].events & POLLOUT) != 0);
  	}
  
  #ifdef USE_WATCHER_THREAD
  	if (have_ctlevent)
  		done = process_ctlfd(manager);
  #endif
  
  	return (done);
  }
  #elif defined(USE_SELECT)
  static void
  process_fds(isc__socketmgr_t *manager, int maxfd, fd_set *readfds,
  	    fd_set *writefds)
  {
  	int i;
  
  	REQUIRE(maxfd <= (int)manager->maxsocks);
  
  	for (i = 0; i < maxfd; i++) {
  #ifdef USE_WATCHER_THREAD
  		if (i == manager->pipe_fds[0] || i == manager->pipe_fds[1])
  			continue;
  #endif /* USE_WATCHER_THREAD */
  		process_fd(manager, i, FD_ISSET(i, readfds),
  			   FD_ISSET(i, writefds));
  	}
  }
  #endif
  
  #ifdef USE_WATCHER_THREAD
  static isc_boolean_t
  process_ctlfd(isc__socketmgr_t *manager) {
  	int msg, fd;
  
  	for (;;) {
  		select_readmsg(manager, &fd, &msg);
  
  		manager_log(manager, IOEVENT,
  			    isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
  					   ISC_MSG_WATCHERMSG,
  					   "watcher got message %d "
  					   "for socket %d"), msg, fd);
  
  		/*
  		 * Nothing to read?
  		 */
  		if (msg == SELECT_POKE_NOTHING)
  			break;
  
  		/*
  		 * Handle shutdown message.  We really should
  		 * jump out of this loop right away, but
  		 * it doesn't matter if we have to do a little
  		 * more work first.
  		 */
  		if (msg == SELECT_POKE_SHUTDOWN)
  			return (ISC_TRUE);
  
  		/*
  		 * This is a wakeup on a socket.  Look
  		 * at the event queue for both read and write,
  		 * and decide if we need to watch on it now
  		 * or not.
  		 */
  		wakeup_socket(manager, fd, msg);
  	}
  
  	return (ISC_FALSE);
  }
  
  /*
   * This is the thread that will loop forever, always in a select or poll
   * call.
   *
   * When select returns something to do, track down what thread gets to do
   * this I/O and post the event to it.
   */
  static isc_threadresult_t
  watcher(void *uap) {
  	isc__socketmgr_t *manager = uap;
  	isc_boolean_t done;
  	int cc;
  #ifdef USE_KQUEUE
  	const char *fnname = "kevent()";
  #elif defined (USE_EPOLL)
  	const char *fnname = "epoll_wait()";
  #elif defined(USE_DEVPOLL)
  	const char *fnname = "ioctl(DP_POLL)";
  	struct dvpoll dvp;
  #elif defined (USE_SELECT)
  	const char *fnname = "select()";
  	int maxfd;
  	int ctlfd;
  #endif
  	char strbuf[ISC_STRERRORSIZE];
  #ifdef ISC_SOCKET_USE_POLLWATCH
  	pollstate_t pollstate = poll_idle;
  #endif
  
  #if defined (USE_SELECT)
  	/*
  	 * Get the control fd here.  This will never change.
  	 */
  	ctlfd = manager->pipe_fds[0];
  #endif
  	done = ISC_FALSE;
  	while (!done) {
  		do {
  #ifdef USE_KQUEUE
  			cc = kevent(manager->kqueue_fd, NULL, 0,
  				    manager->events, manager->nevents, NULL);
  #elif defined(USE_EPOLL)
  			cc = epoll_wait(manager->epoll_fd, manager->events,
  					manager->nevents, -1);
  #elif defined(USE_DEVPOLL)
  			dvp.dp_fds = manager->events;
  			dvp.dp_nfds = manager->nevents;
  #ifndef ISC_SOCKET_USE_POLLWATCH
  			dvp.dp_timeout = -1;
  #else
  			if (pollstate == poll_idle)
  				dvp.dp_timeout = -1;
  			else
  				dvp.dp_timeout = ISC_SOCKET_POLLWATCH_TIMEOUT;
  #endif	/* ISC_SOCKET_USE_POLLWATCH */
  			cc = ioctl(manager->devpoll_fd, DP_POLL, &dvp);
  #elif defined(USE_SELECT)
  			LOCK(&manager->lock);
  			memmove(manager->read_fds_copy, manager->read_fds,
  				manager->fd_bufsize);
  			memmove(manager->write_fds_copy, manager->write_fds,
  				manager->fd_bufsize);
  			maxfd = manager->maxfd + 1;
  			UNLOCK(&manager->lock);
  
  			cc = select(maxfd, manager->read_fds_copy,
  				    manager->write_fds_copy, NULL, NULL);
  #endif	/* USE_KQUEUE */
  
  			if (cc < 0 && !SOFT_ERROR(errno)) {
  				isc__strerror(errno, strbuf, sizeof(strbuf));
  				FATAL_ERROR(__FILE__, __LINE__,
  					    "%s %s: %s", fnname,
  					    isc_msgcat_get(isc_msgcat,
  							   ISC_MSGSET_GENERAL,
  							   ISC_MSG_FAILED,
  							   "failed"), strbuf);
  			}
  
  #if defined(USE_DEVPOLL) && defined(ISC_SOCKET_USE_POLLWATCH)
  			if (cc == 0) {
  				if (pollstate == poll_active)
  					pollstate = poll_checking;
  				else if (pollstate == poll_checking)
  					pollstate = poll_idle;
  			} else if (cc > 0) {
  				if (pollstate == poll_checking) {
  					/*
  					 * XXX: We'd like to use a more
  					 * verbose log level as it's actually an
  					 * unexpected event, but the kernel bug
  					 * reportedly happens pretty frequently
  					 * (and it can also be a false positive)
  					 * so it would be just too noisy.
  					 */
  					manager_log(manager,
  						    ISC_LOGCATEGORY_GENERAL,
  						    ISC_LOGMODULE_SOCKET,
  						    ISC_LOG_DEBUG(1),
  						    "unexpected POLL timeout");
  				}
  				pollstate = poll_active;
  			}
  #endif
  		} while (cc < 0);
  
  #if defined(USE_KQUEUE) || defined (USE_EPOLL) || defined (USE_DEVPOLL)
  		done = process_fds(manager, manager->events, cc);
  #elif defined(USE_SELECT)
  		process_fds(manager, maxfd, manager->read_fds_copy,
  			    manager->write_fds_copy);
  
  		/*
  		 * Process reads on internal, control fd.
  		 */
  		if (FD_ISSET(ctlfd, manager->read_fds_copy))
  			done = process_ctlfd(manager);
  #endif
  	}
  
  	manager_log(manager, TRACE, "%s",
  		    isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  				   ISC_MSG_EXITING, "watcher exiting"));
  
  	return ((isc_threadresult_t)0);
  }
  #endif /* USE_WATCHER_THREAD */
  
  #ifdef BIND9
  ISC_SOCKETFUNC_SCOPE void
  isc__socketmgr_setreserved(isc_socketmgr_t *manager0, isc_uint32_t reserved) {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  
  	REQUIRE(VALID_MANAGER(manager));
  
  	manager->reserved = reserved;
  }
  
  ISC_SOCKETFUNC_SCOPE void
  isc___socketmgr_maxudp(isc_socketmgr_t *manager0, int maxudp) {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  
  	REQUIRE(VALID_MANAGER(manager));
  
  	manager->maxudp = maxudp;
  }
  #endif	/* BIND9 */
  
  /*
   * Create a new socket manager.
   */
  
  static isc_result_t
  setup_watcher(isc_mem_t *mctx, isc__socketmgr_t *manager) {
  	isc_result_t result;
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
  	char strbuf[ISC_STRERRORSIZE];
  #endif
  
  #ifdef USE_KQUEUE
  	manager->nevents = ISC_SOCKET_MAXEVENTS;
  	manager->events = isc_mem_get(mctx, sizeof(struct kevent) *
  				      manager->nevents);
  	if (manager->events == NULL)
  		return (ISC_R_NOMEMORY);
  	manager->kqueue_fd = kqueue();
  	if (manager->kqueue_fd == -1) {
  		result = isc__errno2result(errno);
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "kqueue %s: %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct kevent) * manager->nevents);
  		return (result);
  	}
  
  #ifdef USE_WATCHER_THREAD
  	result = watch_fd(manager, manager->pipe_fds[0], SELECT_POKE_READ);
  	if (result != ISC_R_SUCCESS) {
  		close(manager->kqueue_fd);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct kevent) * manager->nevents);
  		return (result);
  	}
  #endif	/* USE_WATCHER_THREAD */
  #elif defined(USE_EPOLL)
  	manager->nevents = ISC_SOCKET_MAXEVENTS;
  	manager->events = isc_mem_get(mctx, sizeof(struct epoll_event) *
  				      manager->nevents);
  	if (manager->events == NULL)
  		return (ISC_R_NOMEMORY);
  	manager->epoll_fd = epoll_create(manager->nevents);
  	if (manager->epoll_fd == -1) {
  		result = isc__errno2result(errno);
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "epoll_create %s: %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct epoll_event) * manager->nevents);
  		return (result);
  	}
  #ifdef USE_WATCHER_THREAD
  	result = watch_fd(manager, manager->pipe_fds[0], SELECT_POKE_READ);
  	if (result != ISC_R_SUCCESS) {
  		close(manager->epoll_fd);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct epoll_event) * manager->nevents);
  		return (result);
  	}
  #endif	/* USE_WATCHER_THREAD */
  #elif defined(USE_DEVPOLL)
  	/*
  	 * XXXJT: /dev/poll seems to reject large numbers of events,
  	 * so we should be careful about redefining ISC_SOCKET_MAXEVENTS.
  	 */
  	manager->nevents = ISC_SOCKET_MAXEVENTS;
  	manager->events = isc_mem_get(mctx, sizeof(struct pollfd) *
  				      manager->nevents);
  	if (manager->events == NULL)
  		return (ISC_R_NOMEMORY);
  	/*
  	 * Note: fdpollinfo should be able to support all possible FDs, so
  	 * it must have maxsocks entries (not nevents).
  	 */
  	manager->fdpollinfo = isc_mem_get(mctx, sizeof(pollinfo_t) *
  					  manager->maxsocks);
  	if (manager->fdpollinfo == NULL) {
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct pollfd) * manager->nevents);
  		return (ISC_R_NOMEMORY);
  	}
  	memset(manager->fdpollinfo, 0, sizeof(pollinfo_t) * manager->maxsocks);
  	manager->devpoll_fd = open("/dev/poll", O_RDWR);
  	if (manager->devpoll_fd == -1) {
  		result = isc__errno2result(errno);
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "open(/dev/poll) %s: %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct pollfd) * manager->nevents);
  		isc_mem_put(mctx, manager->fdpollinfo,
  			    sizeof(pollinfo_t) * manager->maxsocks);
  		return (result);
  	}
  #ifdef USE_WATCHER_THREAD
  	result = watch_fd(manager, manager->pipe_fds[0], SELECT_POKE_READ);
  	if (result != ISC_R_SUCCESS) {
  		close(manager->devpoll_fd);
  		isc_mem_put(mctx, manager->events,
  			    sizeof(struct pollfd) * manager->nevents);
  		isc_mem_put(mctx, manager->fdpollinfo,
  			    sizeof(pollinfo_t) * manager->maxsocks);
  		return (result);
  	}
  #endif	/* USE_WATCHER_THREAD */
  #elif defined(USE_SELECT)
  	UNUSED(result);
  
  #if ISC_SOCKET_MAXSOCKETS > FD_SETSIZE
  	/*
  	 * Note: this code should also cover the case of MAXSOCKETS <=
  	 * FD_SETSIZE, but we separate the cases to avoid possible portability
  	 * issues regarding howmany() and the actual representation of fd_set.
  	 */
  	manager->fd_bufsize = howmany(manager->maxsocks, NFDBITS) *
  		sizeof(fd_mask);
  #else
  	manager->fd_bufsize = sizeof(fd_set);
  #endif
  
  	manager->read_fds = NULL;
  	manager->read_fds_copy = NULL;
  	manager->write_fds = NULL;
  	manager->write_fds_copy = NULL;
  
  	manager->read_fds = isc_mem_get(mctx, manager->fd_bufsize);
  	if (manager->read_fds != NULL)
  		manager->read_fds_copy = isc_mem_get(mctx, manager->fd_bufsize);
  	if (manager->read_fds_copy != NULL)
  		manager->write_fds = isc_mem_get(mctx, manager->fd_bufsize);
  	if (manager->write_fds != NULL) {
  		manager->write_fds_copy = isc_mem_get(mctx,
  						      manager->fd_bufsize);
  	}
  	if (manager->write_fds_copy == NULL) {
  		if (manager->write_fds != NULL) {
  			isc_mem_put(mctx, manager->write_fds,
  				    manager->fd_bufsize);
  		}
  		if (manager->read_fds_copy != NULL) {
  			isc_mem_put(mctx, manager->read_fds_copy,
  				    manager->fd_bufsize);
  		}
  		if (manager->read_fds != NULL) {
  			isc_mem_put(mctx, manager->read_fds,
  				    manager->fd_bufsize);
  		}
  		return (ISC_R_NOMEMORY);
  	}
  	memset(manager->read_fds, 0, manager->fd_bufsize);
  	memset(manager->write_fds, 0, manager->fd_bufsize);
  
  #ifdef USE_WATCHER_THREAD
  	(void)watch_fd(manager, manager->pipe_fds[0], SELECT_POKE_READ);
  	manager->maxfd = manager->pipe_fds[0];
  #else /* USE_WATCHER_THREAD */
  	manager->maxfd = 0;
  #endif /* USE_WATCHER_THREAD */
  #endif	/* USE_KQUEUE */
  
  	return (ISC_R_SUCCESS);
  }
  
  static void
  cleanup_watcher(isc_mem_t *mctx, isc__socketmgr_t *manager) {
  #ifdef USE_WATCHER_THREAD
  	isc_result_t result;
  
  	result = unwatch_fd(manager, manager->pipe_fds[0], SELECT_POKE_READ);
  	if (result != ISC_R_SUCCESS) {
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "epoll_ctl(DEL) %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"));
  	}
  #endif	/* USE_WATCHER_THREAD */
  
  #ifdef USE_KQUEUE
  	close(manager->kqueue_fd);
  	isc_mem_put(mctx, manager->events,
  		    sizeof(struct kevent) * manager->nevents);
  #elif defined(USE_EPOLL)
  	close(manager->epoll_fd);
  	isc_mem_put(mctx, manager->events,
  		    sizeof(struct epoll_event) * manager->nevents);
  #elif defined(USE_DEVPOLL)
  	close(manager->devpoll_fd);
  	isc_mem_put(mctx, manager->events,
  		    sizeof(struct pollfd) * manager->nevents);
  	isc_mem_put(mctx, manager->fdpollinfo,
  		    sizeof(pollinfo_t) * manager->maxsocks);
  #elif defined(USE_SELECT)
  	if (manager->read_fds != NULL)
  		isc_mem_put(mctx, manager->read_fds, manager->fd_bufsize);
  	if (manager->read_fds_copy != NULL)
  		isc_mem_put(mctx, manager->read_fds_copy, manager->fd_bufsize);
  	if (manager->write_fds != NULL)
  		isc_mem_put(mctx, manager->write_fds, manager->fd_bufsize);
  	if (manager->write_fds_copy != NULL)
  		isc_mem_put(mctx, manager->write_fds_copy, manager->fd_bufsize);
  #endif	/* USE_KQUEUE */
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socketmgr_create(isc_mem_t *mctx, isc_socketmgr_t **managerp) {
  	return (isc__socketmgr_create2(mctx, managerp, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socketmgr_create2(isc_mem_t *mctx, isc_socketmgr_t **managerp,
  		       unsigned int maxsocks)
  {
  	int i;
  	isc__socketmgr_t *manager;
  #ifdef USE_WATCHER_THREAD
  	char strbuf[ISC_STRERRORSIZE];
  #endif
  	isc_result_t result;
  
  	REQUIRE(managerp != NULL && *managerp == NULL);
  
  #ifdef USE_SHARED_MANAGER
  	if (socketmgr != NULL) {
  		/* Don't allow maxsocks to be updated */
  		if (maxsocks > 0 && socketmgr->maxsocks != maxsocks)
  			return (ISC_R_EXISTS);
  
  		socketmgr->refs++;
  		*managerp = (isc_socketmgr_t *)socketmgr;
  		return (ISC_R_SUCCESS);
  	}
  #endif /* USE_SHARED_MANAGER */
  
  	if (maxsocks == 0)
  		maxsocks = ISC_SOCKET_MAXSOCKETS;
  
  	manager = isc_mem_get(mctx, sizeof(*manager));
  	if (manager == NULL)
  		return (ISC_R_NOMEMORY);
  
  	/* zero-clear so that necessary cleanup on failure will be easy */
  	memset(manager, 0, sizeof(*manager));
  	manager->maxsocks = maxsocks;
  	manager->reserved = 0;
  	manager->maxudp = 0;
  	manager->fds = isc_mem_get(mctx,
  				   manager->maxsocks * sizeof(isc__socket_t *));
  	if (manager->fds == NULL) {
  		result = ISC_R_NOMEMORY;
  		goto free_manager;
  	}
  	manager->fdstate = isc_mem_get(mctx, manager->maxsocks * sizeof(int));
  	if (manager->fdstate == NULL) {
  		result = ISC_R_NOMEMORY;
  		goto free_manager;
  	}
  	manager->stats = NULL;
  
  	manager->common.methods = &socketmgrmethods;
  	manager->common.magic = ISCAPI_SOCKETMGR_MAGIC;
  	manager->common.impmagic = SOCKET_MANAGER_MAGIC;
  	manager->mctx = NULL;
  	memset(manager->fds, 0, manager->maxsocks * sizeof(isc_socket_t *));
  	ISC_LIST_INIT(manager->socklist);
  	result = isc_mutex_init(&manager->lock);
  	if (result != ISC_R_SUCCESS)
  		goto free_manager;
  	manager->fdlock = isc_mem_get(mctx, FDLOCK_COUNT * sizeof(isc_mutex_t));
  	if (manager->fdlock == NULL) {
  		result = ISC_R_NOMEMORY;
  		goto cleanup_lock;
  	}
  	for (i = 0; i < FDLOCK_COUNT; i++) {
  		result = isc_mutex_init(&manager->fdlock[i]);
  		if (result != ISC_R_SUCCESS) {
  			while (--i >= 0)
  				DESTROYLOCK(&manager->fdlock[i]);
  			isc_mem_put(mctx, manager->fdlock,
  				    FDLOCK_COUNT * sizeof(isc_mutex_t));
  			manager->fdlock = NULL;
  			goto cleanup_lock;
  		}
  	}
  
  #ifdef USE_WATCHER_THREAD
  	if (isc_condition_init(&manager->shutdown_ok) != ISC_R_SUCCESS) {
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "isc_condition_init() %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"));
  		result = ISC_R_UNEXPECTED;
  		goto cleanup_lock;
  	}
  
  	/*
  	 * Create the special fds that will be used to wake up the
  	 * select/poll loop when something internal needs to be done.
  	 */
  	if (pipe(manager->pipe_fds) != 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "pipe() %s: %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"),
  				 strbuf);
  		result = ISC_R_UNEXPECTED;
  		goto cleanup_condition;
  	}
  
  	RUNTIME_CHECK(make_nonblock(manager->pipe_fds[0]) == ISC_R_SUCCESS);
  #if 0
  	RUNTIME_CHECK(make_nonblock(manager->pipe_fds[1]) == ISC_R_SUCCESS);
  #endif
  #endif	/* USE_WATCHER_THREAD */
  
  #ifdef USE_SHARED_MANAGER
  	manager->refs = 1;
  #endif /* USE_SHARED_MANAGER */
  
  	/*
  	 * Set up initial state for the select loop
  	 */
  	result = setup_watcher(mctx, manager);
  	if (result != ISC_R_SUCCESS)
  		goto cleanup;
  	memset(manager->fdstate, 0, manager->maxsocks * sizeof(int));
  #ifdef USE_WATCHER_THREAD
  	/*
  	 * Start up the select/poll thread.
  	 */
  	if (isc_thread_create(watcher, manager, &manager->watcher) !=
  	    ISC_R_SUCCESS) {
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "isc_thread_create() %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"));
  		cleanup_watcher(mctx, manager);
  		result = ISC_R_UNEXPECTED;
  		goto cleanup;
  	}
  #endif /* USE_WATCHER_THREAD */
  	isc_mem_attach(mctx, &manager->mctx);
  
  #ifdef USE_SHARED_MANAGER
  	socketmgr = manager;
  #endif /* USE_SHARED_MANAGER */
  	*managerp = (isc_socketmgr_t *)manager;
  
  	return (ISC_R_SUCCESS);
  
  cleanup:
  #ifdef USE_WATCHER_THREAD
  	(void)close(manager->pipe_fds[0]);
  	(void)close(manager->pipe_fds[1]);
  #endif	/* USE_WATCHER_THREAD */
  
  #ifdef USE_WATCHER_THREAD
  cleanup_condition:
  	(void)isc_condition_destroy(&manager->shutdown_ok);
  #endif	/* USE_WATCHER_THREAD */
  
  
  cleanup_lock:
  	if (manager->fdlock != NULL) {
  		for (i = 0; i < FDLOCK_COUNT; i++)
  			DESTROYLOCK(&manager->fdlock[i]);
  	}
  	DESTROYLOCK(&manager->lock);
  
  free_manager:
  	if (manager->fdlock != NULL) {
  		isc_mem_put(mctx, manager->fdlock,
  			    FDLOCK_COUNT * sizeof(isc_mutex_t));
  	}
  	if (manager->fdstate != NULL) {
  		isc_mem_put(mctx, manager->fdstate,
  			    manager->maxsocks * sizeof(int));
  	}
  	if (manager->fds != NULL) {
  		isc_mem_put(mctx, manager->fds,
  			    manager->maxsocks * sizeof(isc_socket_t *));
  	}
  	isc_mem_put(mctx, manager, sizeof(*manager));
  
  	return (result);
  }
  
  #ifdef BIND9
  isc_result_t
  isc__socketmgr_getmaxsockets(isc_socketmgr_t *manager0, unsigned int *nsockp) {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  	REQUIRE(VALID_MANAGER(manager));
  	REQUIRE(nsockp != NULL);
  
  	*nsockp = manager->maxsocks;
  
  	return (ISC_R_SUCCESS);
  }
  
  void
  isc__socketmgr_setstats(isc_socketmgr_t *manager0, isc_stats_t *stats) {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  
  	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);
  }
  #endif
  
  ISC_SOCKETFUNC_SCOPE 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 = (isc__socketmgr_t *)*managerp;
  	REQUIRE(VALID_MANAGER(manager));
  
  #ifdef USE_SHARED_MANAGER
  	manager->refs--;
  	if (manager->refs > 0) {
  		*managerp = NULL;
  		return;
  	}
  	socketmgr = NULL;
  #endif /* USE_SHARED_MANAGER */
  
  	LOCK(&manager->lock);
  
  	/*
  	 * Wait for all sockets to be destroyed.
  	 */
  	while (!ISC_LIST_EMPTY(manager->socklist)) {
  #ifdef USE_WATCHER_THREAD
  		manager_log(manager, CREATION, "%s",
  			    isc_msgcat_get(isc_msgcat, ISC_MSGSET_SOCKET,
  					   ISC_MSG_SOCKETSREMAIN,
  					   "sockets exist"));
  		WAIT(&manager->shutdown_ok, &manager->lock);
  #else /* USE_WATCHER_THREAD */
  		UNLOCK(&manager->lock);
  		isc__taskmgr_dispatch(NULL);
  		LOCK(&manager->lock);
  #endif /* USE_WATCHER_THREAD */
  	}
  
  	UNLOCK(&manager->lock);
  
  	/*
  	 * Here, poke our select/poll thread.  Do this by closing the write
  	 * half of the pipe, which will send EOF to the read half.
  	 * This is currently a no-op in the non-threaded case.
  	 */
  	select_poke(manager, 0, SELECT_POKE_SHUTDOWN);
  
  #ifdef USE_WATCHER_THREAD
  	/*
  	 * Wait for thread to exit.
  	 */
  	if (isc_thread_join(manager->watcher, NULL) != ISC_R_SUCCESS)
  		UNEXPECTED_ERROR(__FILE__, __LINE__,
  				 "isc_thread_join() %s",
  				 isc_msgcat_get(isc_msgcat, ISC_MSGSET_GENERAL,
  						ISC_MSG_FAILED, "failed"));
  #endif /* USE_WATCHER_THREAD */
  
  	/*
  	 * Clean up.
  	 */
  	cleanup_watcher(manager->mctx, manager);
  
  #ifdef USE_WATCHER_THREAD
  	(void)close(manager->pipe_fds[0]);
  	(void)close(manager->pipe_fds[1]);
  	(void)isc_condition_destroy(&manager->shutdown_ok);
  #endif /* USE_WATCHER_THREAD */
  
  	for (i = 0; i < (int)manager->maxsocks; i++)
  		if (manager->fdstate[i] == CLOSE_PENDING) /* no need to lock */
  			(void)close(i);
  
  	isc_mem_put(manager->mctx, manager->fds,
  		    manager->maxsocks * sizeof(isc__socket_t *));
  	isc_mem_put(manager->mctx, manager->fdstate,
  		    manager->maxsocks * sizeof(int));
  
  	if (manager->stats != NULL)
  		isc_stats_detach(&manager->stats);
  
  	if (manager->fdlock != NULL) {
  		for (i = 0; i < FDLOCK_COUNT; i++)
  			DESTROYLOCK(&manager->fdlock[i]);
  		isc_mem_put(manager->mctx, manager->fdlock,
  			    FDLOCK_COUNT * sizeof(isc_mutex_t));
  	}
  	DESTROYLOCK(&manager->lock);
  	manager->common.magic = 0;
  	manager->common.impmagic = 0;
  	mctx= manager->mctx;
  	isc_mem_put(mctx, manager, sizeof(*manager));
  
  	isc_mem_detach(&mctx);
  
  	*managerp = NULL;
  
  #ifdef USE_SHARED_MANAGER
  	socketmgr = NULL;
  #endif
  }
  
  static isc_result_t
  socket_recv(isc__socket_t *sock, isc_socketevent_t *dev, isc_task_t *task,
  	    unsigned int flags)
  {
  	int io_state;
  	isc_boolean_t have_lock = ISC_FALSE;
  	isc_task_t *ntask = NULL;
  	isc_result_t result = ISC_R_SUCCESS;
  
  	dev->ev_sender = task;
  
  	if (sock->type == isc_sockettype_udp) {
  		io_state = doio_recv(sock, dev);
  	} else {
  		LOCK(&sock->lock);
  		have_lock = ISC_TRUE;
  
  		if (ISC_LIST_EMPTY(sock->recv_list))
  			io_state = doio_recv(sock, dev);
  		else
  			io_state = DOIO_SOFT;
  	}
  
  	switch (io_state) {
  	case DOIO_SOFT:
  		/*
  		 * We couldn't read all or part of the request right now, so
  		 * queue it.
  		 *
  		 * Attach to socket and to task
  		 */
  		isc_task_attach(task, &ntask);
  		dev->attributes |= ISC_SOCKEVENTATTR_ATTACHED;
  
  		if (!have_lock) {
  			LOCK(&sock->lock);
  			have_lock = ISC_TRUE;
  		}
  
  		/*
  		 * Enqueue the request.  If the socket was previously not being
  		 * watched, poke the watcher to start paying attention to it.
  		 */
  		if (ISC_LIST_EMPTY(sock->recv_list) && !sock->pending_recv)
  			select_poke(sock->manager, sock->fd, SELECT_POKE_READ);
  		ISC_LIST_ENQUEUE(sock->recv_list, dev, ev_link);
  
  		socket_log(sock, NULL, EVENT, NULL, 0, 0,
  			   "socket_recv: event %p -> task %p",
  			   dev, ntask);
  
  		if ((flags & ISC_SOCKFLAG_IMMEDIATE) != 0)
  			result = ISC_R_INPROGRESS;
  		break;
  
  	case DOIO_EOF:
  		dev->result = ISC_R_EOF;
  		/* fallthrough */
  
  	case DOIO_HARD:
  	case DOIO_SUCCESS:
  		if ((flags & ISC_SOCKFLAG_IMMEDIATE) == 0)
  			send_recvdone_event(sock, &dev);
  		break;
  	}
  
  	if (have_lock)
  		UNLOCK(&sock->lock);
  
  	return (result);
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_recvv(isc_socket_t *sock0, isc_bufferlist_t *buflist,
  		  unsigned int minimum, isc_task_t *task,
  		  isc_taskaction_t action, const void *arg)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socketevent_t *dev;
  	isc__socketmgr_t *manager;
  	unsigned int iocount;
  	isc_buffer_t *buffer;
  
  	REQUIRE(VALID_SOCKET(sock));
  	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)
  		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);
  	}
  
  	return (socket_recv(sock, dev, task, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_recv(isc_socket_t *sock0, isc_region_t *region,
  		 unsigned int minimum, isc_task_t *task,
  		 isc_taskaction_t action, const void *arg)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socketevent_t *dev;
  	isc__socketmgr_t *manager;
  
  	REQUIRE(VALID_SOCKET(sock));
  	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)
  		return (ISC_R_NOMEMORY);
  
  	return (isc__socket_recv2(sock0, region, minimum, task, dev, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_recv2(isc_socket_t *sock0, isc_region_t *region,
  		  unsigned int minimum, isc_task_t *task,
  		  isc_socketevent_t *event, unsigned int flags)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	event->ev_sender = sock;
  	event->result = ISC_R_UNSET;
  	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;
  	}
  
  	return (socket_recv(sock, event, task, flags));
  }
  
  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;
  	isc_boolean_t have_lock = ISC_FALSE;
  	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) {
  		dev->attributes |= ISC_SOCKEVENTATTR_PKTINFO;
  		dev->pktinfo = *pktinfo;
  
  		if (!isc_sockaddr_issitelocal(&dev->address) &&
  		    !isc_sockaddr_islinklocal(&dev->address)) {
  			socket_log(sock, NULL, TRACE, isc_msgcat,
  				   ISC_MSGSET_SOCKET, ISC_MSG_PKTINFOPROVIDED,
  				   "pktinfo structure provided, ifindex %u "
  				   "(set to 0)", pktinfo->ipi6_ifindex);
  
  			/*
  			 * Set the pktinfo index to 0 here, to let the
  			 * kernel decide what interface it should send on.
  			 */
  			dev->pktinfo.ipi6_ifindex = 0;
  		}
  	}
  
  	if (sock->type == isc_sockettype_udp)
  		io_state = doio_send(sock, dev);
  	else {
  		LOCK(&sock->lock);
  		have_lock = ISC_TRUE;
  
  		if (ISC_LIST_EMPTY(sock->send_list))
  			io_state = doio_send(sock, dev);
  		else
  			io_state = DOIO_SOFT;
  	}
  
  	switch (io_state) {
  	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;
  
  			if (!have_lock) {
  				LOCK(&sock->lock);
  				have_lock = ISC_TRUE;
  			}
  
  			/*
  			 * Enqueue the request.  If the socket was previously
  			 * not being watched, poke the watcher to start
  			 * paying attention to it.
  			 */
  			if (ISC_LIST_EMPTY(sock->send_list) &&
  			    !sock->pending_send)
  				select_poke(sock->manager, sock->fd,
  					    SELECT_POKE_WRITE);
  			ISC_LIST_ENQUEUE(sock->send_list, dev, ev_link);
  
  			socket_log(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_HARD:
  	case DOIO_SUCCESS:
  		if ((flags & ISC_SOCKFLAG_IMMEDIATE) == 0)
  			send_senddone_event(sock, &dev);
  		break;
  	}
  
  	if (have_lock)
  		UNLOCK(&sock->lock);
  
  	return (result);
  }
  
  ISC_SOCKETFUNC_SCOPE 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_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_sendto(isc_socket_t *sock0, isc_region_t *region,
  		   isc_task_t *task, isc_taskaction_t action, const void *arg,
  		   isc_sockaddr_t *address, struct in6_pktinfo *pktinfo)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socketevent_t *dev;
  	isc__socketmgr_t *manager;
  
  	REQUIRE(VALID_SOCKET(sock));
  	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)
  		return (ISC_R_NOMEMORY);
  
  	dev->region = *region;
  
  	return (socket_send(sock, dev, task, address, pktinfo, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE 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_sendtov2(sock, buflist, task, action, arg, NULL,
  				     NULL, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE 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)
  {
  	return (isc__socket_sendtov2(sock, buflist, task, action, arg, address,
  				     pktinfo, 0));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_sendtov2(isc_socket_t *sock0, isc_bufferlist_t *buflist,
  		     isc_task_t *task, isc_taskaction_t action, const void *arg,
  		     isc_sockaddr_t *address, struct in6_pktinfo *pktinfo,
  		     unsigned int flags)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socketevent_t *dev;
  	isc__socketmgr_t *manager;
  	unsigned int iocount;
  	isc_buffer_t *buffer;
  
  	REQUIRE(VALID_SOCKET(sock));
  	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)
  		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);
  	}
  
  	return (socket_send(sock, dev, task, address, pktinfo, flags));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_sendto2(isc_socket_t *sock0, isc_region_t *region,
  		    isc_task_t *task,
  		    isc_sockaddr_t *address, struct in6_pktinfo *pktinfo,
  		    isc_socketevent_t *event, unsigned int flags)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(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_UNSET;
  	ISC_LIST_INIT(event->bufferlist);
  	event->region = *region;
  	event->n = 0;
  	event->offset = 0;
  	event->attributes = 0;
  
  	return (socket_send(sock, event, task, address, pktinfo, flags));
  }
  
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_cleanunix(isc_sockaddr_t *sockaddr, isc_boolean_t active) {
  #ifdef ISC_PLATFORM_HAVESYSUNH
  	int s;
  	struct stat sb;
  	char strbuf[ISC_STRERRORSIZE];
  
  	if (sockaddr->type.sa.sa_family != AF_UNIX)
  		return;
  
  #ifndef S_ISSOCK
  #if defined(S_IFMT) && defined(S_IFSOCK)
  #define S_ISSOCK(mode) ((mode & S_IFMT)==S_IFSOCK)
  #elif defined(_S_IFMT) && defined(S_IFSOCK)
  #define S_ISSOCK(mode) ((mode & _S_IFMT)==S_IFSOCK)
  #endif
  #endif
  
  #ifndef S_ISFIFO
  #if defined(S_IFMT) && defined(S_IFIFO)
  #define S_ISFIFO(mode) ((mode & S_IFMT)==S_IFIFO)
  #elif defined(_S_IFMT) && defined(S_IFIFO)
  #define S_ISFIFO(mode) ((mode & _S_IFMT)==S_IFIFO)
  #endif
  #endif
  
  #if !defined(S_ISFIFO) && !defined(S_ISSOCK)
  #error You need to define S_ISFIFO and S_ISSOCK as appropriate for your platform.  See <sys/stat.h>.
  #endif
  
  #ifndef S_ISFIFO
  #define S_ISFIFO(mode) 0
  #endif
  
  #ifndef S_ISSOCK
  #define S_ISSOCK(mode) 0
  #endif
  
  	if (active) {
  		if (stat(sockaddr->type.sunix.sun_path, &sb) < 0) {
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				      "isc_socket_cleanunix: stat(%s): %s",
  				      sockaddr->type.sunix.sun_path, strbuf);
  			return;
  		}
  		if (!(S_ISSOCK(sb.st_mode) || S_ISFIFO(sb.st_mode))) {
  			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				      "isc_socket_cleanunix: %s: not a socket",
  				      sockaddr->type.sunix.sun_path);
  			return;
  		}
  		if (unlink(sockaddr->type.sunix.sun_path) < 0) {
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  				      "isc_socket_cleanunix: unlink(%s): %s",
  				      sockaddr->type.sunix.sun_path, strbuf);
  		}
  		return;
  	}
  
  	s = socket(AF_UNIX, SOCK_STREAM, 0);
  	if (s < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			      ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
  			      "isc_socket_cleanunix: socket(%s): %s",
  			      sockaddr->type.sunix.sun_path, strbuf);
  		return;
  	}
  
  	if (stat(sockaddr->type.sunix.sun_path, &sb) < 0) {
  		switch (errno) {
  		case ENOENT:    /* We exited cleanly last time */
  			break;
  		default:
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				      ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
  				      "isc_socket_cleanunix: stat(%s): %s",
  				      sockaddr->type.sunix.sun_path, strbuf);
  			break;
  		}
  		goto cleanup;
  	}
  
  	if (!(S_ISSOCK(sb.st_mode) || S_ISFIFO(sb.st_mode))) {
  		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			      ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
  			      "isc_socket_cleanunix: %s: not a socket",
  			      sockaddr->type.sunix.sun_path);
  		goto cleanup;
  	}
  
  	if (connect(s, (struct sockaddr *)&sockaddr->type.sunix,
  		    sizeof(sockaddr->type.sunix)) < 0) {
  		switch (errno) {
  		case ECONNREFUSED:
  		case ECONNRESET:
  			if (unlink(sockaddr->type.sunix.sun_path) < 0) {
  				isc__strerror(errno, strbuf, sizeof(strbuf));
  				isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  					      ISC_LOGMODULE_SOCKET,
  					      ISC_LOG_WARNING,
  					      "isc_socket_cleanunix: "
  					      "unlink(%s): %s",
  					      sockaddr->type.sunix.sun_path,
  					      strbuf);
  			}
  			break;
  		default:
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  				      ISC_LOGMODULE_SOCKET, ISC_LOG_WARNING,
  				      "isc_socket_cleanunix: connect(%s): %s",
  				      sockaddr->type.sunix.sun_path, strbuf);
  			break;
  		}
  	}
   cleanup:
  	close(s);
  #else
  	UNUSED(sockaddr);
  	UNUSED(active);
  #endif
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_permunix(isc_sockaddr_t *sockaddr, isc_uint32_t perm,
  		    isc_uint32_t owner, isc_uint32_t group)
  {
  #ifdef ISC_PLATFORM_HAVESYSUNH
  	isc_result_t result = ISC_R_SUCCESS;
  	char strbuf[ISC_STRERRORSIZE];
  	char path[sizeof(sockaddr->type.sunix.sun_path)];
  #ifdef NEED_SECURE_DIRECTORY
  	char *slash;
  #endif
  
  	REQUIRE(sockaddr->type.sa.sa_family == AF_UNIX);
  	INSIST(strlen(sockaddr->type.sunix.sun_path) < sizeof(path));
  	strcpy(path, sockaddr->type.sunix.sun_path);
  
  #ifdef NEED_SECURE_DIRECTORY
  	slash = strrchr(path, '/');
  	if (slash != NULL) {
  		if (slash != path)
  			*slash = '\0';
  		else
  			strcpy(path, "/");
  	} else
  		strcpy(path, ".");
  #endif
  
  	if (chmod(path, perm) < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  			      "isc_socket_permunix: chmod(%s, %d): %s",
  			      path, perm, strbuf);
  		result = ISC_R_FAILURE;
  	}
  	if (chown(path, owner, group) < 0) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		isc_log_write(isc_lctx, ISC_LOGCATEGORY_GENERAL,
  			      ISC_LOGMODULE_SOCKET, ISC_LOG_ERROR,
  			      "isc_socket_permunix: chown(%s, %d, %d): %s",
  			      path, owner, group,
  			      strbuf);
  		result = ISC_R_FAILURE;
  	}
  	return (result);
  #else
  	UNUSED(sockaddr);
  	UNUSED(perm);
  	UNUSED(owner);
  	UNUSED(group);
  	return (ISC_R_NOTIMPLEMENTED);
  #endif
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_bind(isc_socket_t *sock0, isc_sockaddr_t *sockaddr,
  		 unsigned int options) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	char strbuf[ISC_STRERRORSIZE];
  	int on = 1;
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  
  	INSIST(!sock->bound);
  	INSIST(!sock->dupped);
  
  	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.
  	 */
  #ifdef AF_UNIX
  	if (sock->pf == AF_UNIX)
  		goto bind_socket;
  #endif
  	if ((options & ISC_SOCKET_REUSEADDRESS) != 0 &&
  	    isc_sockaddr_getport(sockaddr) != (in_port_t)0 &&
  	    setsockopt(sock->fd, SOL_SOCKET, SO_REUSEADDR, (void *)&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... */
  	}
  #ifdef AF_UNIX
   bind_socket:
  #endif
  	if (bind(sock->fd, &sockaddr->type.sa, sockaddr->length) < 0) {
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_BINDFAIL]);
  
  		UNLOCK(&sock->lock);
  		switch (errno) {
  		case EACCES:
  			return (ISC_R_NOPERM);
  		case EADDRNOTAVAIL:
  			return (ISC_R_ADDRNOTAVAIL);
  		case EADDRINUSE:
  			return (ISC_R_ADDRINUSE);
  		case EINVAL:
  			return (ISC_R_BOUND);
  		default:
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			UNEXPECTED_ERROR(__FILE__, __LINE__, "bind: %s",
  					 strbuf);
  			return (ISC_R_UNEXPECTED);
  		}
  	}
  
  	socket_log(sock, sockaddr, TRACE,
  		   isc_msgcat, ISC_MSGSET_SOCKET, ISC_MSG_BOUND, "bound");
  	sock->bound = 1;
  
  	UNLOCK(&sock->lock);
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * Enable this only for specific OS versions, and only when they have repaired
   * their problems with it.  Until then, this is is broken and needs to be
   * diabled by default.  See RT22589 for details.
   */
  #undef ENABLE_ACCEPTFILTER
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_filter(isc_socket_t *sock0, const char *filter) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  #if defined(SO_ACCEPTFILTER) && defined(ENABLE_ACCEPTFILTER)
  	char strbuf[ISC_STRERRORSIZE];
  	struct accept_filter_arg afa;
  #else
  	UNUSED(sock);
  	UNUSED(filter);
  #endif
  
  	REQUIRE(VALID_SOCKET(sock));
  
  #if defined(SO_ACCEPTFILTER) && defined(ENABLE_ACCEPTFILTER)
  	bzero(&afa, sizeof(afa));
  	strncpy(afa.af_name, filter, sizeof(afa.af_name));
  	if (setsockopt(sock->fd, SOL_SOCKET, SO_ACCEPTFILTER,
  			 &afa, sizeof(afa)) == -1) {
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		socket_log(sock, NULL, CREATION, isc_msgcat, ISC_MSGSET_SOCKET,
  			   ISC_MSG_FILTER, "setsockopt(SO_ACCEPTFILTER): %s",
  			   strbuf);
  		return (ISC_R_FAILURE);
  	}
  	return (ISC_R_SUCCESS);
  #else
  	return (ISC_R_NOTIMPLEMENTED);
  #endif
  }
  
  /*
   * 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_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_listen(isc_socket_t *sock0, unsigned int backlog) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	char strbuf[ISC_STRERRORSIZE];
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  
  	REQUIRE(!sock->listener);
  	REQUIRE(sock->bound);
  	REQUIRE(sock->type == isc_sockettype_tcp ||
  		sock->type == isc_sockettype_unix);
  
  	if (backlog == 0)
  		backlog = SOMAXCONN;
  
  	if (listen(sock->fd, (int)backlog) < 0) {
  		UNLOCK(&sock->lock);
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  
  		UNEXPECTED_ERROR(__FILE__, __LINE__, "listen: %s", strbuf);
  
  		return (ISC_R_UNEXPECTED);
  	}
  
  	sock->listener = 1;
  
  	UNLOCK(&sock->lock);
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * This should try to do aggressive accept() XXXMLG
   */
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_accept(isc_socket_t *sock0,
  		  isc_task_t *task, isc_taskaction_t action, const void *arg)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socket_newconnev_t *dev;
  	isc__socketmgr_t *manager;
  	isc_task_t *ntask = NULL;
  	isc__socket_t *nsock;
  	isc_result_t result;
  	isc_boolean_t do_poke = ISC_FALSE;
  
  	REQUIRE(VALID_SOCKET(sock));
  	manager = sock->manager;
  	REQUIRE(VALID_MANAGER(manager));
  
  	LOCK(&sock->lock);
  
  	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.
  	 */
  	dev = (isc_socket_newconnev_t *)
  		isc_event_allocate(manager->mctx, task, ISC_SOCKEVENT_NEWCONN,
  				   action, arg, sizeof(*dev));
  	if (dev == NULL) {
  		UNLOCK(&sock->lock);
  		return (ISC_R_NOMEMORY);
  	}
  	ISC_LINK_INIT(dev, ev_link);
  
  	result = allocate_socket(manager, sock->type, &nsock);
  	if (result != ISC_R_SUCCESS) {
  		isc_event_free(ISC_EVENT_PTR(&dev));
  		UNLOCK(&sock->lock);
  		return (result);
  	}
  
  	/*
  	 * Attach to socket and to task.
  	 */
  	isc_task_attach(task, &ntask);
  	if (isc_task_exiting(ntask)) {
  		free_socket(&nsock);
  		isc_task_detach(&ntask);
  		isc_event_free(ISC_EVENT_PTR(&dev));
  		UNLOCK(&sock->lock);
  		return (ISC_R_SHUTTINGDOWN);
  	}
  	nsock->references++;
  	nsock->statsindex = sock->statsindex;
  
  	dev->ev_sender = ntask;
  	dev->newsocket = (isc_socket_t *)nsock;
  
  	/*
  	 * Poke watcher here.  We still have the socket locked, so there
  	 * is no race condition.  We will keep the lock for such a short
  	 * bit of time waking it up now or later won't matter all that much.
  	 */
  	if (ISC_LIST_EMPTY(sock->accept_list))
  		do_poke = ISC_TRUE;
  
  	ISC_LIST_ENQUEUE(sock->accept_list, dev, ev_link);
  
  	if (do_poke)
  		select_poke(manager, sock->fd, SELECT_POKE_ACCEPT);
  
  	UNLOCK(&sock->lock);
  	return (ISC_R_SUCCESS);
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_connect(isc_socket_t *sock0, isc_sockaddr_t *addr,
  		   isc_task_t *task, isc_taskaction_t action, const void *arg)
  {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_socket_connev_t *dev;
  	isc_task_t *ntask = NULL;
  	isc__socketmgr_t *manager;
  	int cc;
  	char strbuf[ISC_STRERRORSIZE];
  	char addrbuf[ISC_SOCKADDR_FORMATSIZE];
  
  	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);
  
  	REQUIRE(!sock->connecting);
  
  	dev = (isc_socket_connev_t *)isc_event_allocate(manager->mctx, sock,
  							ISC_SOCKEVENT_CONNECT,
  							action,	arg,
  							sizeof(*dev));
  	if (dev == NULL) {
  		UNLOCK(&sock->lock);
  		return (ISC_R_NOMEMORY);
  	}
  	ISC_LINK_INIT(dev, ev_link);
  
  	/*
  	 * Try to do the connect right away, as there can be only one
  	 * outstanding, and it might happen to complete.
  	 */
  	sock->peer_address = *addr;
  	cc = connect(sock->fd, &addr->type.sa, addr->length);
  	if (cc < 0) {
  		/*
  		 * HP-UX "fails" to connect a UDP socket and sets errno to
  		 * EINPROGRESS if it's non-blocking.  We'd rather regard this as
  		 * a success and let the user detect it if it's really an error
  		 * at the time of sending a packet on the socket.
  		 */
  		if (sock->type == isc_sockettype_udp && errno == EINPROGRESS) {
  			cc = 0;
  			goto success;
  		}
  		if (SOFT_ERROR(errno) || errno == EINPROGRESS)
  			goto queue;
  
  		switch (errno) {
  #define ERROR_MATCH(a, b) case a: dev->result = b; goto err_exit;
  			ERROR_MATCH(EACCES, ISC_R_NOPERM);
  			ERROR_MATCH(EADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
  			ERROR_MATCH(EAFNOSUPPORT, ISC_R_ADDRNOTAVAIL);
  			ERROR_MATCH(ECONNREFUSED, ISC_R_CONNREFUSED);
  			ERROR_MATCH(EHOSTUNREACH, ISC_R_HOSTUNREACH);
  #ifdef EHOSTDOWN
  			ERROR_MATCH(EHOSTDOWN, ISC_R_HOSTUNREACH);
  #endif
  			ERROR_MATCH(ENETUNREACH, ISC_R_NETUNREACH);
  			ERROR_MATCH(ENOBUFS, ISC_R_NORESOURCES);
  			ERROR_MATCH(EPERM, ISC_R_HOSTUNREACH);
  			ERROR_MATCH(EPIPE, ISC_R_NOTCONNECTED);
  			ERROR_MATCH(ECONNRESET, ISC_R_CONNECTIONRESET);
  #undef ERROR_MATCH
  		}
  
  		sock->connected = 0;
  
  		isc__strerror(errno, strbuf, sizeof(strbuf));
  		isc_sockaddr_format(addr, addrbuf, sizeof(addrbuf));
  		UNEXPECTED_ERROR(__FILE__, __LINE__, "connect(%s) %d/%s",
  				 addrbuf, errno, strbuf);
  
  		UNLOCK(&sock->lock);
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_CONNECTFAIL]);
  		isc_event_free(ISC_EVENT_PTR(&dev));
  		return (ISC_R_UNEXPECTED);
  
  	err_exit:
  		sock->connected = 0;
  		isc_task_send(task, ISC_EVENT_PTR(&dev));
  
  		UNLOCK(&sock->lock);
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_CONNECTFAIL]);
  		return (ISC_R_SUCCESS);
  	}
  
  	/*
  	 * If connect completed, fire off the done event.
  	 */
   success:
  	if (cc == 0) {
  		sock->connected = 1;
  		sock->bound = 1;
  		dev->result = ISC_R_SUCCESS;
  		isc_task_send(task, ISC_EVENT_PTR(&dev));
  
  		UNLOCK(&sock->lock);
  
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_CONNECT]);
  
  		return (ISC_R_SUCCESS);
  	}
  
   queue:
  
  	/*
  	 * Attach to task.
  	 */
  	isc_task_attach(task, &ntask);
  
  	sock->connecting = 1;
  
  	dev->ev_sender = ntask;
  
  	/*
  	 * Poke watcher here.  We still have the socket locked, so there
  	 * is no race condition.  We will keep the lock for such a short
  	 * bit of time waking it up now or later won't matter all that much.
  	 */
  	if (sock->connect_ev == NULL)
  		select_poke(manager, sock->fd, SELECT_POKE_CONNECT);
  
  	sock->connect_ev = dev;
  
  	UNLOCK(&sock->lock);
  	return (ISC_R_SUCCESS);
  }
  
  /*
   * Called when a socket with a pending connect() finishes.
   */
  static void
  internal_connect(isc_task_t *me, isc_event_t *ev) {
  	isc__socket_t *sock;
  	isc_socket_connev_t *dev;
  	isc_task_t *task;
  	int cc;
  	ISC_SOCKADDR_LEN_T optlen;
  	char strbuf[ISC_STRERRORSIZE];
  	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
  
  	UNUSED(me);
  	INSIST(ev->ev_type == ISC_SOCKEVENT_INTW);
  
  	sock = ev->ev_sender;
  	INSIST(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  
  	/*
  	 * When the internal event was sent the reference count was bumped
  	 * to keep the socket around for us.  Decrement the count here.
  	 */
  	INSIST(sock->references > 0);
  	sock->references--;
  	if (sock->references == 0) {
  		UNLOCK(&sock->lock);
  		destroy(&sock);
  		return;
  	}
  
  	/*
  	 * Has this event been canceled?
  	 */
  	dev = sock->connect_ev;
  	if (dev == NULL) {
  		INSIST(!sock->connecting);
  		UNLOCK(&sock->lock);
  		return;
  	}
  
  	INSIST(sock->connecting);
  	sock->connecting = 0;
  
  	/*
  	 * Get any possible error status here.
  	 */
  	optlen = sizeof(cc);
  	if (getsockopt(sock->fd, SOL_SOCKET, SO_ERROR,
  		       (void *)&cc, (void *)&optlen) < 0)
  		cc = errno;
  	else
  		errno = cc;
  
  	if (errno != 0) {
  		/*
  		 * If the error is EAGAIN, just re-select on this
  		 * fd and pretend nothing strange happened.
  		 */
  		if (SOFT_ERROR(errno) || errno == EINPROGRESS) {
  			sock->connecting = 1;
  			select_poke(sock->manager, sock->fd,
  				    SELECT_POKE_CONNECT);
  			UNLOCK(&sock->lock);
  
  			return;
  		}
  
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_CONNECTFAIL]);
  
  		/*
  		 * Translate other errors into ISC_R_* flavors.
  		 */
  		switch (errno) {
  #define ERROR_MATCH(a, b) case a: dev->result = b; break;
  			ERROR_MATCH(EACCES, ISC_R_NOPERM);
  			ERROR_MATCH(EADDRNOTAVAIL, ISC_R_ADDRNOTAVAIL);
  			ERROR_MATCH(EAFNOSUPPORT, ISC_R_ADDRNOTAVAIL);
  			ERROR_MATCH(ECONNREFUSED, ISC_R_CONNREFUSED);
  			ERROR_MATCH(EHOSTUNREACH, ISC_R_HOSTUNREACH);
  #ifdef EHOSTDOWN
  			ERROR_MATCH(EHOSTDOWN, ISC_R_HOSTUNREACH);
  #endif
  			ERROR_MATCH(ENETUNREACH, ISC_R_NETUNREACH);
  			ERROR_MATCH(ENOBUFS, ISC_R_NORESOURCES);
  			ERROR_MATCH(EPERM, ISC_R_HOSTUNREACH);
  			ERROR_MATCH(EPIPE, ISC_R_NOTCONNECTED);
  			ERROR_MATCH(ETIMEDOUT, ISC_R_TIMEDOUT);
  			ERROR_MATCH(ECONNRESET, ISC_R_CONNECTIONRESET);
  #undef ERROR_MATCH
  		default:
  			dev->result = ISC_R_UNEXPECTED;
  			isc_sockaddr_format(&sock->peer_address, peerbuf,
  					    sizeof(peerbuf));
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "internal_connect: connect(%s) %s",
  					 peerbuf, strbuf);
  		}
  	} else {
  		inc_stats(sock->manager->stats,
  			  sock->statsindex[STATID_CONNECT]);
  		dev->result = ISC_R_SUCCESS;
  		sock->connected = 1;
  		sock->bound = 1;
  	}
  
  	sock->connect_ev = NULL;
  
  	UNLOCK(&sock->lock);
  
  	task = dev->ev_sender;
  	dev->ev_sender = sock;
  	isc_task_sendanddetach(&task, ISC_EVENT_PTR(&dev));
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_getpeername(isc_socket_t *sock0, isc_sockaddr_t *addressp) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_result_t result;
  
  	REQUIRE(VALID_SOCKET(sock));
  	REQUIRE(addressp != NULL);
  
  	LOCK(&sock->lock);
  
  	if (sock->connected) {
  		*addressp = sock->peer_address;
  		result = ISC_R_SUCCESS;
  	} else {
  		result = ISC_R_NOTCONNECTED;
  	}
  
  	UNLOCK(&sock->lock);
  
  	return (result);
  }
  
  ISC_SOCKETFUNC_SCOPE isc_result_t
  isc__socket_getsockname(isc_socket_t *sock0, isc_sockaddr_t *addressp) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	ISC_SOCKADDR_LEN_T len;
  	isc_result_t result;
  	char strbuf[ISC_STRERRORSIZE];
  
  	REQUIRE(VALID_SOCKET(sock));
  	REQUIRE(addressp != NULL);
  
  	LOCK(&sock->lock);
  
  	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(errno, 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.
   */
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_cancel(isc_socket_t *sock0, isc_task_t *task, unsigned int how) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	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);
  
  	/*
  	 * 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_LIST_EMPTY(sock->recv_list)) {
  		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;
  		}
  	}
  
  	if (((how & ISC_SOCKCANCEL_SEND) == ISC_SOCKCANCEL_SEND)
  	    && !ISC_LIST_EMPTY(sock->send_list)) {
  		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;
  		}
  	}
  
  	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)) {
  
  				ISC_LIST_UNLINK(sock->accept_list, dev,
  						ev_link);
  
  				NEWCONNSOCK(dev)->references--;
  				free_socket((isc__socket_t **)&dev->newsocket);
  
  				dev->result = ISC_R_CANCELED;
  				dev->ev_sender = sock;
  				isc_task_sendanddetach(&current_task,
  						       ISC_EVENT_PTR(&dev));
  			}
  
  			dev = next;
  		}
  	}
  
  	/*
  	 * 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->connecting);
  		sock->connecting = 0;
  
  		dev = sock->connect_ev;
  		current_task = dev->ev_sender;
  
  		if ((task == NULL) || (task == current_task)) {
  			sock->connect_ev = NULL;
  
  			dev->result = ISC_R_CANCELED;
  			dev->ev_sender = sock;
  			isc_task_sendanddetach(&current_task,
  					       ISC_EVENT_PTR(&dev));
  		}
  	}
  
  	UNLOCK(&sock->lock);
  }
  
  ISC_SOCKETFUNC_SCOPE isc_sockettype_t
  isc__socket_gettype(isc_socket_t *sock0) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	return (sock->type);
  }
  
  ISC_SOCKETFUNC_SCOPE isc_boolean_t
  isc__socket_isbound(isc_socket_t *sock0) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  	isc_boolean_t val;
  
  	REQUIRE(VALID_SOCKET(sock));
  
  	LOCK(&sock->lock);
  	val = ((sock->bound) ? ISC_TRUE : ISC_FALSE);
  	UNLOCK(&sock->lock);
  
  	return (val);
  }
  
  ISC_SOCKETFUNC_SCOPE void
  isc__socket_ipv6only(isc_socket_t *sock0, isc_boolean_t yes) {
  	isc__socket_t *sock = (isc__socket_t *)sock0;
  #if defined(IPV6_V6ONLY)
  	int onoff = yes ? 1 : 0;
  #else
  	UNUSED(yes);
  	UNUSED(sock);
  #endif
  
  	REQUIRE(VALID_SOCKET(sock));
  	INSIST(!sock->dupped);
  
  #ifdef IPV6_V6ONLY
  	if (sock->pf == AF_INET6) {
  		if (setsockopt(sock->fd, IPPROTO_IPV6, IPV6_V6ONLY,
  			       (void *)&onoff, sizeof(int)) < 0) {
  			char strbuf[ISC_STRERRORSIZE];
  			isc__strerror(errno, strbuf, sizeof(strbuf));
  			UNEXPECTED_ERROR(__FILE__, __LINE__,
  					 "setsockopt(%d, IPV6_V6ONLY) "
  					 "%s: %s", sock->fd,
  					 isc_msgcat_get(isc_msgcat,
  							ISC_MSGSET_GENERAL,
  							ISC_MSG_FAILED,
  							"failed"),
  					 strbuf);
  		}
  	}
  	FIX_IPV6_RECVPKTINFO(sock);	/* AIX */
  #endif
  }
  
  #ifndef USE_WATCHER_THREAD
  /*
   * In our assumed scenario, we can simply use a single static object.
   * XXX: this is not true if the application uses multiple threads with
   *      'multi-context' mode.  Fixing this is a future TODO item.
   */
  static isc_socketwait_t swait_private;
  
  int
  isc__socketmgr_waitevents(isc_socketmgr_t *manager0, struct timeval *tvp,
  			  isc_socketwait_t **swaitp)
  {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  
  
  	int n;
  #ifdef USE_KQUEUE
  	struct timespec ts, *tsp;
  #endif
  #ifdef USE_EPOLL
  	int timeout;
  #endif
  #ifdef USE_DEVPOLL
  	struct dvpoll dvp;
  #endif
  
  	REQUIRE(swaitp != NULL && *swaitp == NULL);
  
  #ifdef USE_SHARED_MANAGER
  	if (manager == NULL)
  		manager = socketmgr;
  #endif
  	if (manager == NULL)
  		return (0);
  
  #ifdef USE_KQUEUE
  	if (tvp != NULL) {
  		ts.tv_sec = tvp->tv_sec;
  		ts.tv_nsec = tvp->tv_usec * 1000;
  		tsp = &ts;
  	} else
  		tsp = NULL;
  	swait_private.nevents = kevent(manager->kqueue_fd, NULL, 0,
  				       manager->events, manager->nevents,
  				       tsp);
  	n = swait_private.nevents;
  #elif defined(USE_EPOLL)
  	if (tvp != NULL)
  		timeout = tvp->tv_sec * 1000 + (tvp->tv_usec + 999) / 1000;
  	else
  		timeout = -1;
  	swait_private.nevents = epoll_wait(manager->epoll_fd,
  					   manager->events,
  					   manager->nevents, timeout);
  	n = swait_private.nevents;
  #elif defined(USE_DEVPOLL)
  	dvp.dp_fds = manager->events;
  	dvp.dp_nfds = manager->nevents;
  	if (tvp != NULL) {
  		dvp.dp_timeout = tvp->tv_sec * 1000 +
  			(tvp->tv_usec + 999) / 1000;
  	} else
  		dvp.dp_timeout = -1;
  	swait_private.nevents = ioctl(manager->devpoll_fd, DP_POLL, &dvp);
  	n = swait_private.nevents;
  #elif defined(USE_SELECT)
  	memmove(manager->read_fds_copy, manager->read_fds, manager->fd_bufsize);
  	memmove(manager->write_fds_copy, manager->write_fds,
  		manager->fd_bufsize);
  
  	swait_private.readset = manager->read_fds_copy;
  	swait_private.writeset = manager->write_fds_copy;
  	swait_private.maxfd = manager->maxfd + 1;
  
  	n = select(swait_private.maxfd, swait_private.readset,
  		   swait_private.writeset, NULL, tvp);
  #endif
  
  	*swaitp = &swait_private;
  	return (n);
  }
  
  isc_result_t
  isc__socketmgr_dispatch(isc_socketmgr_t *manager0, isc_socketwait_t *swait) {
  	isc__socketmgr_t *manager = (isc__socketmgr_t *)manager0;
  
  	REQUIRE(swait == &swait_private);
  
  #ifdef USE_SHARED_MANAGER
  	if (manager == NULL)
  		manager = socketmgr;
  #endif
  	if (manager == NULL)
  		return (ISC_R_NOTFOUND);
  
  #if defined(USE_KQUEUE) || defined(USE_EPOLL) || defined(USE_DEVPOLL)
  	(void)process_fds(manager, manager->events, swait->nevents);
  	return (ISC_R_SUCCESS);
  #elif defined(USE_SELECT)
  	process_fds(manager, swait->maxfd, swait->readset, swait->writeset);
  	return (ISC_R_SUCCESS);
  #endif
  }
  #endif /* USE_WATCHER_THREAD */
  
  #ifdef BIND9
  void
  isc__socket_setname(isc_socket_t *socket0, const char *name, void *tag) {
  	isc__socket_t *socket = (isc__socket_t *)socket0;
  
  	/*
  	 * 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);
  }
  
  ISC_SOCKETFUNC_SCOPE const char *
  isc__socket_getname(isc_socket_t *socket0) {
  	isc__socket_t *socket = (isc__socket_t *)socket0;
  
  	return (socket->name);
  }
  
  void *
  isc__socket_gettag(isc_socket_t *socket0) {
  	isc__socket_t *socket = (isc__socket_t *)socket0;
  
  	return (socket->tag);
  }
  #endif	/* BIND9 */
  
  #ifdef USE_SOCKETIMPREGISTER
  isc_result_t
  isc__socket_register() {
  	return (isc_socket_register(isc__socketmgr_create));
  }
  #endif
  
  ISC_SOCKETFUNC_SCOPE int
  isc__socket_getfd(isc_socket_t *socket0) {
  	isc__socket_t *socket = (isc__socket_t *)socket0;
  
  	return ((short) socket->fd);
  }
  
  #if defined(HAVE_LIBXML2) && defined(BIND9)
  
  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");
  }
  
  #define TRY0(a) do { xmlrc = (a); if (xmlrc < 0) goto error; } while(0)
  ISC_SOCKETFUNC_SCOPE int
  isc_socketmgr_renderxml(isc_socketmgr_t *mgr0, xmlTextWriterPtr writer) {
  	isc__socketmgr_t *mgr = (isc__socketmgr_t *)mgr0;
  	isc__socket_t *sock = NULL;
  	char peerbuf[ISC_SOCKADDR_FORMATSIZE];
  	isc_sockaddr_t addr;
  	ISC_SOCKADDR_LEN_T len;
  	int xmlrc;
  
  	LOCK(&mgr->lock);
  
  #ifdef USE_SHARED_MANAGER
  	TRY0(xmlTextWriterStartElement(writer, ISC_XMLCHAR "references"));
  	TRY0(xmlTextWriterWriteFormatString(writer, "%d", mgr->refs));
  	TRY0(xmlTextWriterEndElement(writer));
  #endif	/* USE_SHARED_MANAGER */
  
  	TRY0(xmlTextWriterStartElement(writer, ISC_XMLCHAR "sockets"));
  	sock = ISC_LIST_HEAD(mgr->socklist);
  	while (sock != NULL) {
  		LOCK(&sock->lock);
  		TRY0(xmlTextWriterStartElement(writer, ISC_XMLCHAR "socket"));
  
  		TRY0(xmlTextWriterStartElement(writer, ISC_XMLCHAR "id"));
  		TRY0(xmlTextWriterWriteFormatString(writer, "%p", sock));
  		TRY0(xmlTextWriterEndElement(writer));
  
  		if (sock->name[0] != 0) {
  			TRY0(xmlTextWriterStartElement(writer,
  						       ISC_XMLCHAR "name"));
  			TRY0(xmlTextWriterWriteFormatString(writer, "%s",
  							    sock->name));
  			TRY0(xmlTextWriterEndElement(writer)); /* name */
  		}
  
  		TRY0(xmlTextWriterStartElement(writer,
  					       ISC_XMLCHAR "references"));
  		TRY0(xmlTextWriterWriteFormatString(writer, "%d",
  						    sock->references));
  		TRY0(xmlTextWriterEndElement(writer));
  
  		TRY0(xmlTextWriterWriteElement(writer, ISC_XMLCHAR "type",
  					  ISC_XMLCHAR _socktype(sock->type)));
  
  		if (sock->connected) {
  			isc_sockaddr_format(&sock->peer_address, peerbuf,
  					    sizeof(peerbuf));
  			TRY0(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));
  			TRY0(xmlTextWriterWriteElement(writer,
  						  ISC_XMLCHAR "local-address",
  						  ISC_XMLCHAR peerbuf));
  		}
  
  		TRY0(xmlTextWriterStartElement(writer, ISC_XMLCHAR "states"));
  		if (sock->pending_recv)
  			TRY0(xmlTextWriterWriteElement(writer,
  						ISC_XMLCHAR "state",
  						ISC_XMLCHAR "pending-receive"));
  		if (sock->pending_send)
  			TRY0(xmlTextWriterWriteElement(writer,
  						  ISC_XMLCHAR "state",
  						  ISC_XMLCHAR "pending-send"));
  		if (sock->pending_accept)
  			TRY0(xmlTextWriterWriteElement(writer,
  						 ISC_XMLCHAR "state",
  						 ISC_XMLCHAR "pending_accept"));
  		if (sock->listener)
  			TRY0(xmlTextWriterWriteElement(writer,
  						       ISC_XMLCHAR "state",
  						       ISC_XMLCHAR "listener"));
  		if (sock->connected)
  			TRY0(xmlTextWriterWriteElement(writer,
  						     ISC_XMLCHAR "state",
  						     ISC_XMLCHAR "connected"));
  		if (sock->connecting)
  			TRY0(xmlTextWriterWriteElement(writer,
  						    ISC_XMLCHAR "state",
  						    ISC_XMLCHAR "connecting"));
  		if (sock->bound)
  			TRY0(xmlTextWriterWriteElement(writer,
  						       ISC_XMLCHAR "state",
  						       ISC_XMLCHAR "bound"));
  
  		TRY0(xmlTextWriterEndElement(writer)); /* states */
  
  		TRY0(xmlTextWriterEndElement(writer)); /* socket */
  
  		UNLOCK(&sock->lock);
  		sock = ISC_LIST_NEXT(sock, link);
  	}
  	TRY0(xmlTextWriterEndElement(writer)); /* sockets */
  
   error:
  	if (sock != NULL)
  		UNLOCK(&sock->lock);
  
  	UNLOCK(&mgr->lock);
  
  	return (xmlrc);
  }
  #endif /* HAVE_LIBXML2 */
  