socat/xio-socket.c

/* source: xio-socket.c */
/* Copyright Gerhard Rieger */
/* Published under the GNU General Public License V.2, see file COPYING */

/* this file contains the source for socket related functions, and the
   implementation of generic socket addresses */

#include "xiosysincludes.h"

#if _WITH_SOCKET

#include "xioopen.h"
#include "xiosigchld.h"
#include "xio-ascii.h"
#include "xio-socket.h"
#include "xio-named.h"
#include "xio-unix.h"
#if WITH_IP4
#include "xio-ip4.h"
#endif /* WITH_IP4 */
#if WITH_IP6
#include "xio-ip6.h"
#endif /* WITH_IP6 */
#include "xio-ip.h"
#include "xio-listen.h"
#include "xio-ipapp.h"	/*! not clean */
#include "xio-tcpwrap.h"


static
int xioopen_socket_connect(int argc, const char *argv[], struct opt *opts,
			   int xioflags, xiofile_t *xfd, unsigned groups,
			   int dummy1, int dummy2, int dummy3);
static
int xioopen_socket_listen(int argc, const char *argv[], struct opt *opts,
			  int xioflags, xiofile_t *xfd, unsigned groups,
			  int dummy1, int dummy2, int dummy3);
static
int xioopen_socket_sendto(int argc, const char *argv[], struct opt *opts,
			  int xioflags, xiofile_t *xfd, unsigned groups,
			  int dummy1, int dummy2, int dummy3);
static
int xioopen_socket_datagram(int argc, const char *argv[], struct opt *opts,
			    int xioflags, xiofile_t *xfd, unsigned groups,
			    int dummy1, int dummy2, int dummy3);
static
int xioopen_socket_recvfrom(int argc, const char *argv[], struct opt *opts,
			    int xioflags, xiofile_t *xfd, unsigned groups,
			    int dummy1, int socktype, int dummy3);
static
int xioopen_socket_recv(int argc, const char *argv[], struct opt *opts,
			int xioflags, xiofile_t *xfd, unsigned groups, 
			int dumy1, int dummy2, int dummy3);

static
int _xioopen_socket_sendto(const char *pfname, const char *type,
			   const char *proto, const char *address,
			   struct opt *opts, int xioflags, xiofile_t *xxfd,
			   unsigned groups);

static int
xiolog_ancillary_socket(struct cmsghdr *cmsg, int *num,
			char *typbuff, int typlen,
			char *nambuff, int namlen,
			char *envbuff, int envlen,
			char *valbuff, int vallen);


#if WITH_GENERICSOCKET
/* generic socket addresses */
const struct xioaddr_endpoint_desc xioaddr_socket_connect3 = { XIOADDR_ENDPOINT, "socket-connect", 3, XIOBIT_ALL,  GROUP_FD|GROUP_SOCKET|GROUP_CHILD|GROUP_RETRY,                          XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_connect, 0, 0, 0 HELP(":<domain>:<protocol>:<remote-address>") };
const union xioaddr_desc *xioaddrs_socket_connect[] = {
   (union xioaddr_desc *)&xioaddr_socket_connect3,
   NULL
};

#if WITH_LISTEN
const struct xioaddr_endpoint_desc xioaddr_socket_listen3   = { XIOADDR_ENDPOINT, "socket-listen",  3, XIOBIT_ALL,  GROUP_FD|GROUP_SOCKET|GROUP_LISTEN|GROUP_RANGE|GROUP_CHILD|GROUP_RETRY, XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_listen,   0, 0, 0 HELP(":<domain>:<protocol>:<local-address>") };
const union xioaddr_desc *xioaddrs_socket_listen[] = {
   (union xioaddr_desc *)&xioaddr_socket_listen3,
   NULL
};
#endif /* WITH_LISTEN */

const struct xioaddr_endpoint_desc xioaddr_socket_sendto4   = { XIOADDR_ENDPOINT, "socket-sendto",  4, XIOBIT_ALL,  GROUP_FD|GROUP_SOCKET,                                                  XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_sendto,   0, 0, 0 HELP(":<domain>:<type>:<protocol>:<remote-address>") };
const union xioaddr_desc *xioaddrs_socket_sendto[] = {
   (union xioaddr_desc *)&xioaddr_socket_sendto4,
   NULL
};

const struct xioaddr_endpoint_desc xioaddr_socket_datagram4 = { XIOADDR_ENDPOINT, "socket-datagram",4, XIOBIT_ALL,  GROUP_FD|GROUP_SOCKET|GROUP_RANGE,                                      XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_datagram, 0, 0, 0 HELP(":<domain>:<type>:<protocol>:<remote-address>") };
const union xioaddr_desc *xioaddrs_socket_datagram[] = {
   (union xioaddr_desc *)&xioaddr_socket_datagram4,
   NULL
};

const struct xioaddr_endpoint_desc xioaddr_socket_recvfrom4 = { XIOADDR_ENDPOINT, "socket-recvfrom",4, XIOBIT_ALL,  GROUP_FD|GROUP_SOCKET|GROUP_RANGE|GROUP_CHILD,                          XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_recvfrom, 0, 0, 0 HELP(":<domain>:<type>:<protocol>:<local-address>") };
const union xioaddr_desc *xioaddrs_socket_recvfrom[] = {
   (union xioaddr_desc *)&xioaddr_socket_recvfrom4,
   NULL
};

const struct xioaddr_endpoint_desc xioaddr_socket_recv4     = { XIOADDR_ENDPOINT, "socket-recv",    4, XIOBIT_RDONLY,GROUP_FD|GROUP_SOCKET|GROUP_RANGE,                                      XIOSHUT_DOWN, XIOCLOSE_CLOSE, xioopen_socket_recv,     0, 0, 0 HELP(":<domain>:<type>:<protocol>:<local-address>") };
const union xioaddr_desc *xioaddrs_socket_recv[] = {
   (union xioaddr_desc *)&xioaddr_socket_recv4,
   NULL
};
#endif /* WITH_GENERICSOCKET */


/* the following options apply not only to generic socket addresses but to all
   addresses that have anything to do with sockets */
const struct optdesc opt_so_debug    = { "so-debug",    "debug", OPT_SO_DEBUG,    GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_DEBUG };
#ifdef SO_ACCEPTCONN /* AIX433 */
const struct optdesc opt_so_acceptconn={ "so-acceptconn","acceptconn",OPT_SO_ACCEPTCONN,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_ACCEPTCONN};
#endif /* SO_ACCEPTCONN */
const struct optdesc opt_so_broadcast= { "so-broadcast", "broadcast", OPT_SO_BROADCAST,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_BROADCAST};
const struct optdesc opt_so_reuseaddr= { "so-reuseaddr", "reuseaddr", OPT_SO_REUSEADDR,GROUP_SOCKET, PH_PREBIND, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_REUSEADDR};
const struct optdesc opt_so_keepalive= { "so-keepalive", "keepalive", OPT_SO_KEEPALIVE,GROUP_SOCKET, PH_FD, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_KEEPALIVE};
#if HAVE_STRUCT_LINGER
const struct optdesc opt_so_linger   = { "so-linger",    "linger",    OPT_SO_LINGER,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_LINGER,OFUNC_SOCKOPT,SOL_SOCKET, SO_LINGER };
#else /* !HAVE_STRUCT_LINGER */
const struct optdesc opt_so_linger   = { "so-linger",    "linger",    OPT_SO_LINGER,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_LINGER };
#endif /* !HAVE_STRUCT_LINGER */
const struct optdesc opt_so_oobinline= { "so-oobinline", "oobinline", OPT_SO_OOBINLINE,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_OOBINLINE};
const struct optdesc opt_so_sndbuf   = { "so-sndbuf",    "sndbuf",    OPT_SO_SNDBUF,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_SNDBUF};
const struct optdesc opt_so_sndbuf_late={ "so-sndbuf-late","sndbuf-late",OPT_SO_SNDBUF_LATE,GROUP_SOCKET,PH_LATE,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_SNDBUF };
const struct optdesc opt_so_rcvbuf   = { "so-rcvbuf",    "rcvbuf",    OPT_SO_RCVBUF,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_RCVBUF};
const struct optdesc opt_so_rcvbuf_late={"so-rcvbuf-late","rcvbuf-late",OPT_SO_RCVBUF_LATE,GROUP_SOCKET,PH_LATE,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_RCVBUF };
const struct optdesc opt_so_error    = { "so-error",     "error",     OPT_SO_ERROR,    GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_ERROR};
const struct optdesc opt_so_type     = { "so-type",      "type",      OPT_SO_TYPE,     GROUP_SOCKET, PH_SOCKET,     TYPE_INT,  OFUNC_SPEC,    SOL_SOCKET, SO_TYPE };
const struct optdesc opt_so_dontroute= { "so-dontroute", "dontroute", OPT_SO_DONTROUTE,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_DONTROUTE };
#ifdef SO_RCVLOWAT
const struct optdesc opt_so_rcvlowat = { "so-rcvlowat",  "rcvlowat", OPT_SO_RCVLOWAT, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_RCVLOWAT };
#endif
#ifdef SO_RCVTIMEO
const struct optdesc opt_so_rcvtimeo = { "so-rcvtimeo",  "rcvtimeo", OPT_SO_RCVTIMEO, GROUP_SOCKET, PH_PASTSOCKET, TYPE_TIMEVAL,OFUNC_SOCKOPT,SOL_SOCKET,SO_RCVTIMEO };
#endif
#ifdef SO_SNDLOWAT
const struct optdesc opt_so_sndlowat = { "so-sndlowat",  "sndlowat", OPT_SO_SNDLOWAT, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_SNDLOWAT };
#endif
#ifdef SO_SNDTIMEO
const struct optdesc opt_so_sndtimeo = { "so-sndtimeo",  "sndtimeo", OPT_SO_SNDTIMEO, GROUP_SOCKET, PH_PASTSOCKET, TYPE_TIMEVAL,OFUNC_SOCKOPT,SOL_SOCKET,SO_SNDTIMEO };
#endif
/* end of setsockopt options of UNIX98 standard */

#ifdef SO_AUDIT	/* AIX 4.3.3 */
const struct optdesc opt_so_audit    = { "so-audit",     "audit",    OPT_SO_AUDIT,    GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_AUDIT };
#endif /* SO_AUDIT */
#ifdef SO_ATTACH_FILTER
const struct optdesc opt_so_attach_filter={"so-attach-filter","attachfilter",OPT_SO_ATTACH_FILTER,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_ATTACH_FILTER};
#endif
#ifdef SO_DETACH_FILTER
const struct optdesc opt_so_detach_filter={"so-detach-filter","detachfilter",OPT_SO_DETACH_FILTER,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_DETACH_FILTER};
#endif
#ifdef SO_BINDTODEVICE	/* Linux: man 7 socket */
const struct optdesc opt_so_bindtodevice={"so-bindtodevice","if",OPT_SO_BINDTODEVICE,GROUP_SOCKET,PH_PASTSOCKET,TYPE_NAME,OFUNC_SOCKOPT,SOL_SOCKET,SO_BINDTODEVICE};
#endif
#ifdef SO_BSDCOMPAT
const struct optdesc opt_so_bsdcompat= { "so-bsdcompat","bsdcompat",OPT_SO_BSDCOMPAT,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_BSDCOMPAT };
#endif
#ifdef SO_CKSUMRECV
const struct optdesc opt_so_cksumrecv= { "so-cksumrecv","cksumrecv",OPT_SO_CKSUMRECV,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_CKSUMRECV };
#endif /* SO_CKSUMRECV */
#ifdef SO_TIMESTAMP
const struct optdesc opt_so_timestamp= { "so-timestamp","timestamp",OPT_SO_TIMESTAMP,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_TIMESTAMP };
#endif
#ifdef SO_KERNACCEPT	/* AIX 4.3.3 */
const struct optdesc opt_so_kernaccept={ "so-kernaccept","kernaccept",OPT_SO_KERNACCEPT,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_KERNACCEPT};
#endif /* SO_KERNACCEPT */
#ifdef SO_NO_CHECK
const struct optdesc opt_so_no_check = { "so-no-check", "nocheck",OPT_SO_NO_CHECK, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_NO_CHECK };
#endif
#ifdef SO_NOREUSEADDR	/* AIX 4.3.3 */
const struct optdesc opt_so_noreuseaddr={"so-noreuseaddr","noreuseaddr",OPT_SO_NOREUSEADDR,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET, SO_NOREUSEADDR};
#endif /* SO_NOREUSEADDR */
#ifdef SO_PASSCRED
const struct optdesc opt_so_passcred = { "so-passcred", "passcred", OPT_SO_PASSCRED, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_PASSCRED};
#endif
#ifdef SO_PEERCRED
const struct optdesc opt_so_peercred = { "so-peercred", "peercred", OPT_SO_PEERCRED, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT3,OFUNC_SOCKOPT, SOL_SOCKET, SO_PEERCRED};
#endif
#ifdef SO_PRIORITY
const struct optdesc opt_so_priority = { "so-priority", "priority", OPT_SO_PRIORITY, GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_PRIORITY};
#endif
#ifdef SO_REUSEPORT	/* AIX 4.3.3, BSD, HP-UX */
const struct optdesc opt_so_reuseport= { "so-reuseport","reuseport",OPT_SO_REUSEPORT,GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT, OFUNC_SOCKOPT, SOL_SOCKET, SO_REUSEPORT };
#endif /* defined(SO_REUSEPORT) */
#ifdef SO_SECURITY_AUTHENTICATION
const struct optdesc opt_so_security_authentication={"so-security-authentication","securityauthentication",OPT_SO_SECURITY_AUTHENTICATION,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_SECURITY_AUTHENTICATION};
#endif
#ifdef SO_SECURITY_ENCRYPTION_NETWORK
const struct optdesc opt_so_security_encryption_network={"so-security-encryption-network","securityencryptionnetwork",OPT_SO_SECURITY_ENCRYPTION_NETWORK,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_SECURITY_ENCRYPTION_NETWORK};
#endif
#ifdef SO_SECURITY_ENCRYPTION_TRANSPORT
const struct optdesc opt_so_security_encryption_transport={"so-security-encryption-transport","securityencryptiontransport",OPT_SO_SECURITY_ENCRYPTION_TRANSPORT,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_SECURITY_ENCRYPTION_TRANSPORT};
#endif
#ifdef SO_USE_IFBUFS
const struct optdesc opt_so_use_ifbufs={ "so-use-ifbufs","useifbufs",OPT_SO_USE_IFBUFS,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,  OFUNC_SOCKOPT, SOL_SOCKET, SO_USE_IFBUFS};
#endif /* SO_USE_IFBUFS */
#ifdef SO_USELOOPBACK /* AIX433, Solaris, HP-UX */
const struct optdesc opt_so_useloopback={"so-useloopback","useloopback",OPT_SO_USELOOPBACK,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT, SOL_SOCKET, SO_USELOOPBACK};
#endif /* SO_USELOOPBACK */
#ifdef SO_DGRAM_ERRIND	/* Solaris */
const struct optdesc opt_so_dgram_errind={"so-dgram-errind","dgramerrind",OPT_SO_DGRAM_ERRIND,GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_DGRAM_ERRIND};
#endif /* SO_DGRAM_ERRIND */
#ifdef SO_DONTLINGER	/* Solaris */
const struct optdesc opt_so_dontlinger = {"so-dontlinger", "dontlinger",  OPT_SO_DONTLINGER,  GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT,OFUNC_SOCKOPT,SOL_SOCKET,SO_DONTLINGER };
#endif
/* the SO_PROTOTYPE is OS defined on Solaris, HP-UX; we lend this for a more
   general purpose */
const struct optdesc opt_so_prototype  = {"so-prototype",  "prototype",   OPT_SO_PROTOTYPE,   GROUP_SOCKET,PH_SOCKET,    TYPE_INT,OFUNC_SPEC,   SOL_SOCKET,SO_PROTOTYPE };
#ifdef FIOSETOWN
const struct optdesc opt_fiosetown   = { "fiosetown", NULL, OPT_FIOSETOWN,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_IOCTL,  FIOSETOWN };
#endif
#ifdef SIOCSPGRP
const struct optdesc opt_siocspgrp   = { "siocspgrp", NULL, OPT_SIOCSPGRP,   GROUP_SOCKET, PH_PASTSOCKET, TYPE_INT,  OFUNC_IOCTL,  SIOCSPGRP };
#endif
const struct optdesc opt_bind        = { "bind",      NULL, OPT_BIND,        GROUP_SOCKET, PH_BIND, TYPE_STRING,OFUNC_SPEC };
const struct optdesc opt_connect_timeout = { "connect-timeout", NULL, OPT_CONNECT_TIMEOUT, GROUP_SOCKET, PH_PASTSOCKET, TYPE_TIMEVAL, OFUNC_OFFSET, XIO_OFFSETOF(para.socket.connect_timeout) };
const struct optdesc opt_protocol_family = { "protocol-family", "pf", OPT_PROTOCOL_FAMILY, GROUP_SOCKET, PH_PRESOCKET,  TYPE_STRING,  OFUNC_SPEC };
const struct optdesc opt_protocol        = { "protocol",        NULL, OPT_PROTOCOL,        GROUP_SOCKET, PH_PRESOCKET,  TYPE_STRING,  OFUNC_SPEC };

/* generic setsockopt() options */
const struct optdesc opt_setsockopt_int    = { "setsockopt-int",    "sockopt-int",    OPT_SETSOCKOPT_INT,        GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT_INT_INT,     OFUNC_SOCKOPT_GENERIC, 0, 0 };
const struct optdesc opt_setsockopt_bin    = { "setsockopt-bin",    "sockopt-bin",    OPT_SETSOCKOPT_BIN,        GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT_INT_BIN,     OFUNC_SOCKOPT_GENERIC, 0, 0 };
const struct optdesc opt_setsockopt_string = { "setsockopt-string", "sockopt-string", OPT_SETSOCKOPT_STRING,     GROUP_SOCKET,PH_PASTSOCKET,TYPE_INT_INT_STRING,  OFUNC_SOCKOPT_GENERIC, 0, 0 };

const struct optdesc opt_null_eof = { "null-eof", NULL, OPT_NULL_EOF, GROUP_SOCKET, PH_INIT, TYPE_BOOL, OFUNC_OFFSET, XIO_OFFSETOF(para.socket.null_eof) };


#if WITH_GENERICSOCKET

static
int xioopen_socket_connect(int argc, const char *argv[], struct opt *opts,
			   int xioflags, xiofile_t *xxfd, unsigned groups,
			   int dummy1, int dummy2, int dummy3) {
   struct single *xfd = &xxfd->stream;
   int rw = (xioflags&XIO_ACCMODE);
   const char *pfname = argv[1];
   const char *protname = argv[2];
   const char *address = argv[3];
   char *garbage;
   int pf;
   int proto;
   int socktype = SOCK_STREAM;
   int needbind = 0;
   union sockaddr_union them;  socklen_t themlen; size_t themsize;
   union sockaddr_union us;    socklen_t uslen = sizeof(us);
   int result;

   if (argc != 4) {
      Error2("%s: wrong number of parameters (%d instead of 3)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   proto = strtoul(protname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_INIT);
   applyopts(-1, opts, PH_EARLY);

   themsize = 0;
   if ((result =
	dalan(address, (char *)&them.soa.sa_data, &themsize, sizeof(them)))
       < 0) {
      Error1("data too long: \"%s\"", address);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", address);
   }      
   them.soa.sa_family = pf;
   themlen = themsize +
#if HAVE_STRUCT_SOCKADDR_SALEN
      sizeof(them.soa.sa_len) +
#endif
      sizeof(them.soa.sa_family);

   xfd->dtype = XIOREAD_STREAM|XIOWRITE_STREAM;

   socket_init(0, &us);
   if (retropt_bind(opts, 0 /*pf*/, socktype, proto, (struct sockaddr *)&us, &uslen, 3,
		    0, 0)
       != STAT_NOACTION) {
      needbind = true;
      us.soa.sa_family = pf;
   }

   if ((result =
	xioopen_connect(xfd,
			needbind?(struct sockaddr *)&us:NULL, uslen,
			(struct sockaddr *)&them, themlen,
			opts, pf, socktype, proto, false)) != 0) {
      return result;
   }
   if (XIOWITHWR(rw))   xfd->wfd = xfd->rfd;
   if (!XIOWITHRD(rw))  xfd->rfd = -1;
   if ((result = _xio_openlate(xfd, opts)) < 0) {
      return result;
   }
   return STAT_OK;
}

#if WITH_LISTEN
static
int xioopen_socket_listen(int argc, const char *argv[], struct opt *opts,
			  int xioflags, xiofile_t *xxfd, unsigned groups,
			  int dummy1, int dummy2, int dummy3) {
   struct single *xfd = &xxfd->stream;
   const char *pfname = argv[1];
   const char *protname = argv[2];
   const char *usname = argv[3];
   char *garbage;
   int pf;
   int proto;
   int socktype = SOCK_STREAM;
   union sockaddr_union us;  socklen_t uslen; size_t ussize;
   struct opt *opts0;
   int result;

   if (argc != 4) {
      Error2("%s: wrong number of parameters (%d instead of 3)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   proto = strtoul(protname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   socket_init(0, &us);
   ussize = 0;
   if ((result =
	dalan(usname, (char *)&us.soa.sa_data, &ussize, sizeof(us)))
       < 0) {
      Error1("data too long: \"%s\"", usname);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", usname);
   }
   uslen = ussize + sizeof(us.soa.sa_family)
#if HAVE_STRUCT_SOCKADDR_SALEN
      + sizeof(us.soa.sa_len)
#endif
      ;
   us.soa.sa_family = pf;

   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_INIT);
   applyopts(-1, opts, PH_EARLY);

   opts0 = copyopts(opts, GROUP_ALL);

   if ((result =
	xioopen_listen(xfd, xioflags,
		       (struct sockaddr *)&us, uslen,
		       opts, opts0, 0/*instead of pf*/, socktype, proto))
       != STAT_OK)
      return result;
   return STAT_OK;
}
#endif /* WITH_LISTEN */

/* we expect the form: ...:domain:type:protocol:remote-address */
static
int xioopen_socket_sendto(int argc, const char *argv[], struct opt *opts,
			  int xioflags, xiofile_t *xxfd, unsigned groups,
			  int dummy1, int dummy2, int dummy3) {
   int rw = (xioflags&XIO_ACCMODE);
   int result;

   if (argc != 5) {
      Error2("%s: wrong number of parameters (%d instead of 4)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }
   if ((result =
	   _xioopen_socket_sendto(argv[1], argv[2], argv[3], argv[4],
				  opts, xioflags, xxfd, groups))
       != STAT_OK) {
      return result;
   }
   _xio_openlate(&xxfd->stream, opts);
   if (XIOWITHWR(rw))   xxfd->stream.wfd = xxfd->stream.rfd;
   if (!XIOWITHRD(rw))  xxfd->stream.rfd = -1;

   return STAT_OK;
}

/*
   returns the resulting FD in xfd->rfd, independend of xioflags
*/
static
int _xioopen_socket_sendto(const char *pfname, const char *type,
			   const char *protname, const char *address,
			   struct opt *opts, int xioflags, xiofile_t *xxfd,
			   unsigned groups) {
   xiosingle_t *xfd = &xxfd->stream;
   int rw = (xioflags&XIO_ACCMODE);
   char *garbage;
   union sockaddr_union us = {{0}};
   socklen_t uslen = 0;   size_t ussize;
   size_t themsize;
   int pf;
   int socktype = SOCK_RAW;
   int proto;
   bool needbind = false;
   char *bindstring = NULL;
   int result;

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   socktype = strtoul(type, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   proto = strtoul(protname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   xfd->peersa.soa.sa_family = pf;
   themsize = 0;
   if ((result =
	dalan(address, (char *)&xfd->peersa.soa.sa_data, &themsize,
	      sizeof(xfd->peersa)))
       < 0) {
      Error1("data too long: \"%s\"", address);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", address);
   }
   xfd->salen = themsize + sizeof(sa_family_t)
#if HAVE_STRUCT_SOCKADDR_SALEN
      + sizeof(xfd->peersa.soa.sa_len)
#endif
      ;
#if HAVE_STRUCT_SOCKADDR_SALEN
   xfd->peersa.soa.sa_len =
      sizeof(xfd->peersa.soa.sa_len) + sizeof(xfd->peersa.soa.sa_family) +
      themsize;
#endif

   /* ...res_opts[] */
   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return -1;
   applyopts(-1, opts, PH_INIT);

   if (pf == PF_UNSPEC) {
      pf = xfd->peersa.soa.sa_family;
   }

   xfd->dtype = XIODATA_RECVFROM;

   if (retropt_string(opts, OPT_BIND, &bindstring) == 0) {
      ussize = 0;
      if ((result =
	   dalan(bindstring, (char *)&us.soa.sa_data, &ussize, sizeof(us)))
	  < 0) {
	 Error1("data too long: \"%s\"", bindstring);
      } else if (result > 0) {
	 Error1("syntax error in \"%s\"", bindstring);
      }
      us.soa.sa_family = pf;
      uslen = ussize + sizeof(sa_family_t)
#if HAVE_STRUCT_SOCKADDR_SALEN
	 + sizeof(us.soa.sa_len)
#endif
	 ;
      needbind = true;
   }

   if ((result =
	_xioopen_dgram_sendto(needbind?&us:NULL, uslen,
			      opts, xioflags, xfd, groups, pf, socktype, proto))
       != STAT_OK) {
      return result;
   }
   if (XIOWITHWR(rw))   xfd->wfd = xfd->rfd;
   if (!XIOWITHRD(rw))  xfd->rfd = -1;
   return STAT_OK;
}


/* we expect the form: ...:domain:socktype:protocol:local-address */
static
int xioopen_socket_recvfrom(int argc, const char *argv[], struct opt *opts,
		     int xioflags, xiofile_t *xxfd, unsigned groups,
		     int dummy, int summy2, int dummy3) {
   struct single *xfd = &xxfd->stream;
   const char *pfname = argv[1];
   const char *typename = argv[2];
   const char *protname = argv[3];
   const char *address = argv[4];
   char *garbage;
   union sockaddr_union *us = &xfd->para.socket.la;
   socklen_t uslen; size_t ussize;
   int pf, socktype, proto;
   char *rangename;
   int result;

   if (argc != 5) {
      Error2("%s: wrong number of parameters (%d instead of 4)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   socktype = strtoul(typename, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   proto = strtoul(protname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   ussize = 0;
   if ((result =
	dalan(address, (char *)&us->soa.sa_data, &ussize, sizeof(*us)))
       < 0) {
      Error1("data too long: \"%s\"", address);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", address);
   }      
   us->soa.sa_family = pf;
   uslen = ussize + sizeof(us->soa.sa_family)
#if HAVE_STRUCT_SOCKADDR_SALEN
      + sizeof(us->soa.sa_len);
#endif
      ;
   xfd->dtype = XIOREAD_RECV|XIOWRITE_SENDTO;

   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, 0, &xfd->para.socket.range) < 0) {
	 return STAT_NORETRY;
      }
      xfd->para.socket.dorange = true;
      free(rangename);
   }

   if ((result =
	_xioopen_dgram_recvfrom(xfd, xioflags, &us->soa, uslen,
				opts, pf, socktype, proto, E_ERROR))
       != STAT_OK) {
      return result;
   }
   _xio_openlate(xfd, opts);
   return STAT_OK;
}

/* we expect the form: ...:domain:type:protocol:local-address */
static
int xioopen_socket_recv(int argc, const char *argv[], struct opt *opts,
		       int xioflags, xiofile_t *xxfd, unsigned groups,
		       int dummy1, int dummy2, int dummy3) {
   struct single *xfd = &xxfd->stream;
   const char *pfname = argv[1];
   const char *typename = argv[2];
   const char *protname = argv[3];
   const char *address = argv[4];
   char *garbage;
   union sockaddr_union us;
   socklen_t uslen; size_t ussize;
   int pf, socktype, proto;
   char *rangename;
   int result;

   if (argc != 5) {
      Error2("%s: wrong number of parameters (%d instead of 4)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   socktype = strtoul(typename, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   proto = strtoul(protname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   retropt_int(opts, OPT_SO_TYPE, &socktype);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   ussize = 0;
   if ((result =
	dalan(address, (char *)&us.soa.sa_data, &ussize, sizeof(us)))
       < 0) {
      Error1("data too long: \"%s\"", address);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", address);
   }      
   us.soa.sa_family = pf;
   uslen = ussize + sizeof(sa_family_t)
#if HAVE_STRUCT_SOCKADDR_SALEN
      +sizeof(us.soa.sa_len)
#endif
      ;
   xfd->dtype = XIOREAD_RECV;
   xfd->para.socket.la.soa.sa_family = pf;

   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, 0, &xfd->para.socket.range) < 0) {
	 return STAT_NORETRY;
      }
      xfd->para.socket.dorange = true;
      free(rangename);
   }

   if ((result =
	_xioopen_dgram_recv(xfd, xioflags, &us.soa,
			    uslen, opts, pf, socktype, proto, E_ERROR))
       != STAT_OK) {
      return result;
   }
   _xio_openlate(xfd, opts);
   return STAT_OK;
}


/* we expect the form: ...:domain:type:protocol:remote-address */
static
int xioopen_socket_datagram(int argc, const char *argv[], struct opt *opts,
			    int xioflags, xiofile_t *xxfd, unsigned groups,
			    int dummy1, int dummy2, int dummy3) {
   xiosingle_t *xfd = &xxfd->stream;
   const char *pfname = argv[1];
   const char *typename = argv[2];
   const char *protname = argv[3];
   const char *address = argv[4];
   char *garbage;
   char *rangename;
   size_t themsize;
   int pf;
   int result;

   if (argc != 5) {
      Error2("%s: wrong number of parameters (%d instead of 4)",
	     argv[0], argc-1);
      return STAT_NORETRY;
   }

   pf = strtoul(pfname, &garbage, 0);
   if (*garbage != '\0') {
      Warn1("garbage in parameter: \"%s\"", garbage);
   }

   retropt_socket_pf(opts, &pf);
   /*retropt_int(opts, OPT_IP_PROTOCOL, &proto);*/

   xfd->peersa.soa.sa_family = pf;
   themsize = 0;
   if ((result =
	dalan(address, (char *)&xfd->peersa.soa.sa_data, &themsize,
	      sizeof(xfd->peersa)))
       < 0) {
      Error1("data too long: \"%s\"", address);
   } else if (result > 0) {
      Error1("syntax error in \"%s\"", address);
   }
   xfd->salen = themsize + sizeof(sa_family_t);
#if HAVE_STRUCT_SOCKADDR_SALEN
   xfd->peersa.soa.sa_len =
      sizeof(xfd->peersa.soa.sa_len) + sizeof(xfd->peersa.soa.sa_family) +
      themsize;
#endif

   if ((result =
	_xioopen_socket_sendto(pfname, typename, protname, address,
			       opts, xioflags, xxfd, groups))
       != STAT_OK) {
      return result;
   }

   xfd->dtype = XIOREAD_RECV|XIOWRITE_SENDTO;

   xfd->para.socket.la.soa.sa_family = xfd->peersa.soa.sa_family;

   /* which reply sockets will accept - determine by range option */
   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, 0, &xfd->para.socket.range) < 0) {
	 free(rangename);
	 return STAT_NORETRY;
      }
      xfd->para.socket.dorange = true;
      xfd->dtype |= XIOREAD_RECV_CHECKRANGE;
      free(rangename);
   }

   _xio_openlate(xfd, opts);
   return STAT_OK;
}

#endif /* WITH_GENERICSOCKET */


/* a subroutine that is common to all socket addresses that want to connect
   to a peer address.
   might fork.
   returns the resulting FD in xfd->rfd
   applies and consumes the following options: 
   PH_PASTSOCKET, PH_FD, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_CONNECT,
   PH_CONNECTED, PH_LATE,
   OFUNC_OFFSET, 
   OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_USER, OPT_GROUP, OPT_CLOEXEC
   returns 0 on success.
*/
int _xioopen_connect(struct single *xfd, struct sockaddr *us, size_t uslen,
		     struct sockaddr *them, size_t themlen,
		     struct opt *opts, int pf, int socktype, int protocol,
		     bool alt, int level) {
   int fcntl_flags = 0;
   char infobuff[256];
   union sockaddr_union la;
   socklen_t lalen = themlen;
   int _errno;
   int result;

   if ((xfd->rfd = xiosocket(opts, pf, socktype, protocol, level)) < 0) {
      return STAT_RETRYLATER;	    
   }
   
   applyopts_offset(xfd, opts);
   applyopts(xfd->rfd, opts, PH_PASTSOCKET);
   applyopts(xfd->rfd, opts, PH_FD);

   applyopts_cloexec(xfd->rfd, opts);

   applyopts(xfd->rfd, opts, PH_PREBIND);
   applyopts(xfd->rfd, opts, PH_BIND);
#if WITH_TCP || WITH_UDP
   if (alt) {
      union sockaddr_union sin, *sinp;
      unsigned short *port, i, N;
      div_t dv;

      /* prepare sockaddr for bind probing */
      if (us) {
	 sinp = (union sockaddr_union *)us;
      } else {
	 if (them->sa_family == AF_INET) {
	    socket_in_init(&sin.ip4);
#if WITH_IP6
	 } else {
	    socket_in6_init(&sin.ip6);
#endif
	 }
	 sinp = &sin;
      }
      if (them->sa_family == AF_INET) {
	 port = &sin.ip4.sin_port;
#if WITH_IP6
      } else if (them->sa_family == AF_INET6) {
	 port = &sin.ip6.sin6_port;
#endif
      } else {
	 port = 0;	/* just to make compiler happy */
      }
      /* combine random+step variant to quickly find a free port when only
	 few are in use, and certainly find a free port in defined time even
	 if there are almost all in use */
      /* dirt 1: having tcp/udp code in socket function */
      /* dirt 2: using a time related system call for init of random */
      {
	 /* generate a random port, with millisecond random init */
#if 0
	 struct timeb tb;
	 ftime(&tb);
	 srandom(tb.time*1000+tb.millitm);
#else
	 struct timeval tv;
	 struct timezone tz;
	 tz.tz_minuteswest = 0;
	 tz.tz_dsttime = 0;
	 if ((result = Gettimeofday(&tv, &tz)) < 0) {
	    Warn2("gettimeofday(%p, {0,0}): %s", &tv, strerror(errno));
	 }
	 srandom(tv.tv_sec*1000000+tv.tv_usec);
#endif
      }
      dv = div(random(), IPPORT_RESERVED-XIO_IPPORT_LOWER);
      i = N = XIO_IPPORT_LOWER + dv.rem;
      do {	/* loop over lowport bind() attempts */
	 *port = htons(i);
	 if (Bind(xfd->rfd, (struct sockaddr *)sinp, sizeof(*sinp)) < 0) {
	    Msg4(errno==EADDRINUSE?E_INFO:level,
		 "bind(%d, {%s}, "F_Zd"): %s", xfd->rfd,
		 sockaddr_info(&sinp->soa, sizeof(*sinp), infobuff, sizeof(infobuff)),
		 sizeof(*sinp), strerror(errno));
	    if (errno != EADDRINUSE) {
	       Close(xfd->rfd);
	       return STAT_RETRYLATER;
	    }
	 } else {
	    break;	/* could bind to port, good, continue past loop */
	 }
	 --i;  if (i < XIO_IPPORT_LOWER)  i = IPPORT_RESERVED-1;
	 if (i == N) {
	    Msg(level, "no low port available");
	    /*errno = EADDRINUSE; still assigned */
	    Close(xfd->rfd);
	    return STAT_RETRYLATER;
	 }
      } while (i != N);
   } else
#endif /* WITH_TCP || WITH_UDP */

   if (us) {
      if (Bind(xfd->rfd, us, uslen) < 0) {
	 Msg4(level, "bind(%d, {%s}, "F_Zd"): %s",
	      xfd->rfd, sockaddr_info(us, uslen, infobuff, sizeof(infobuff)),
	      uslen, strerror(errno));
	 Close(xfd->rfd);
	 return STAT_RETRYLATER;
      }
   }

   applyopts(xfd->rfd, opts, PH_PASTBIND);

   applyopts(xfd->rfd, opts, PH_CONNECT);

   if (xfd->para.socket.connect_timeout.tv_sec  != 0 ||
       xfd->para.socket.connect_timeout.tv_usec != 0) {
      fcntl_flags = Fcntl(xfd->rfd, F_GETFL);
      Fcntl_l(xfd->rfd, F_SETFL, fcntl_flags|O_NONBLOCK);
   }

   result = Connect(xfd->rfd, (struct sockaddr *)them, themlen);
   _errno = errno;
   la.soa.sa_family = them->sa_family;  lalen = sizeof(la);
   if (Getsockname(xfd->rfd, &la.soa, &lalen) < 0) {
      Msg4(level-1, "getsockname(%d, %p, {%d}): %s",
	    xfd->rfd, &la.soa, lalen, strerror(errno));
   }
   errno = _errno;
   if (result < 0) {
      if (errno == EINPROGRESS) {
	 if (xfd->para.socket.connect_timeout.tv_sec  != 0 ||
	     xfd->para.socket.connect_timeout.tv_usec != 0) {
	    struct timeval timeout;
	    struct pollfd writefd;
	    int result;

	    Info4("connect(%d, %s, "F_Zd"): %s",
		  xfd->rfd, sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
		  themlen, strerror(errno));
	    timeout = xfd->para.socket.connect_timeout;
	    writefd.fd = xfd->rfd;
	    writefd.events = (POLLOUT|POLLERR);
	    result = xiopoll(&writefd, 1, &timeout);
	    if (result < 0) {
	       Msg4(level, "xiopoll({%d,POLLOUT|POLLER},,{"F_tv_sec"."F_tv_usec"): %s",
		    xfd->rfd, timeout.tv_sec, timeout.tv_usec, strerror(errno));
	       return STAT_RETRYLATER;
	    }
	    if (result == 0) {
	       Msg2(level, "connecting to %s: %s",
		    sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
		    strerror(ETIMEDOUT));
	       return STAT_RETRYLATER;
	    }
	    if (writefd.revents & POLLERR) {
#if 0
	       unsigned char dummy[1];
	       Read(xfd->rfd, &dummy, 1);        /* get error message */
	       Msg2(level, "connecting to %s: %s",
		    sockaddr_info(them, infobuff, sizeof(infobuff)),
		    strerror(errno));
#else
	       Connect(xfd->rfd, them, themlen); /* get error message */
	       Msg4(level, "connect(%d, %s, "F_Zd"): %s",
		    xfd->rfd, sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
		    themlen, strerror(errno));
#endif
	       return STAT_RETRYLATER;
	    }
	    /* otherwise OK */
	    Fcntl_l(xfd->rfd, F_SETFL, fcntl_flags);
	 } else {
	    Warn4("connect(%d, %s, "F_Zd"): %s",
		  xfd->rfd, sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
		  themlen, strerror(errno));
	 }
      } else if (pf == PF_UNIX && errno == EPROTOTYPE) {
	 /* this is for UNIX domain sockets: a connect attempt seems to be
	    the only way to distinguish stream and datagram sockets */
	 int _errno = errno;
	 Info4("connect(%d, %s, "F_Zd"): %s",
	       xfd->rfd, sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
	       themlen, strerror(errno));
#if 0
	 Info("assuming datagram socket");
	 xfd->dtype = DATA_RECVFROM;
	 xfd->salen = themlen;
	 memcpy(&xfd->peersa.soa, them, xfd->salen);
#endif
	 /*!!! and remove bind socket */
	 Close(xfd->rfd);  xfd->rfd = -1;
	 errno = _errno;
	 return -1;
      } else {
	 Msg4(level, "connect(%d, %s, "F_Zd"): %s",
	      xfd->rfd, sockaddr_info(them, themlen, infobuff, sizeof(infobuff)),
	      themlen, strerror(errno));
	 Close(xfd->rfd);
	 return STAT_RETRYLATER;
      }
   } else {    /* result >= 0 */
      Notice1("successfully connected from local address %s",
	      sockaddr_info(&la.soa, themlen, infobuff, sizeof(infobuff)));
   }

   applyopts_fchown(xfd->rfd, opts);	/* OPT_USER, OPT_GROUP */
   applyopts(xfd->rfd, opts, PH_CONNECTED);
   applyopts(xfd->rfd, opts, PH_LATE);

   return STAT_OK;
}


/* a subroutine that is common to all socket addresses that want to connect
   to a peer address.
   might fork.
   applies and consumes the following option:
   PH_PASTSOCKET, PH_FD, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_CONNECT,
   PH_CONNECTED, PH_LATE,
   OFUNC_OFFSET, 
   OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_USER, OPT_GROUP, OPT_CLOEXEC
   returns the resulting FD in xfd->rfd, independend of xioflags
   returns 0 on success.
*/
int xioopen_connect(struct single *xfd, struct sockaddr *us, size_t uslen,
		    struct sockaddr *them, size_t themlen,
		    struct opt *opts, int pf, int socktype, int protocol,
		    bool alt) {
   bool dofork = false;
   struct opt *opts0;
   char infobuff[256];
   int level;
   int result;

   retropt_bool(opts, OPT_FORK, &dofork);

   opts0 = copyopts(opts, GROUP_ALL);

   Notice1("opening connection to %s",
	   sockaddr_info(them, themlen, infobuff, sizeof(infobuff)));

   do {	/* loop over retries and forks */

#if WITH_RETRY
      if (xfd->forever || xfd->retry) {
	 level = E_INFO;
      } else
#endif /* WITH_RETRY */
	 level = E_ERROR;
      result =
	 _xioopen_connect(xfd, us, uslen, them, themlen, opts,
			  pf, socktype, protocol, alt, level);
      switch (result) {
      case STAT_OK: break;
#if WITH_RETRY
      case STAT_RETRYLATER:
	 if (xfd->forever || xfd->retry) {
	    --xfd->retry;
	    if (result == STAT_RETRYLATER) {
	       Nanosleep(&xfd->intervall, NULL);
	    }
	    dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
	    continue;
	 }
	 return STAT_NORETRY;
#endif /* WITH_RETRY */
      default:
	 return result;
      }

      if (dofork) {
	 xiosetchilddied();	/* set SIGCHLD handler */
      }

#if WITH_RETRY
      if (dofork) {
	 pid_t pid;
	 int level = E_ERROR;
	 if (xfd->forever || xfd->retry) {
	    level = E_WARN;	/* most users won't expect a problem here,
				   so Notice is too weak */
	 }

	 while ((pid = xio_fork(false, level)) < 0) {
	    --xfd->retry;
	    if (xfd->forever || xfd->retry) {
	       dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
	       Nanosleep(&xfd->intervall, NULL); continue;
	    }
	    return STAT_RETRYLATER;
	 }

	 if (pid == 0) {	/* child process */
	    break;
	 }

	 /* parent process */
	 Notice1("forked off child process "F_pid, pid);
	 Close(xfd->rfd);
	 /* with and without retry */
	 Nanosleep(&xfd->intervall, NULL);
	 dropopts(opts, PH_ALL); opts = copyopts(opts0, GROUP_ALL);
	 continue;	/* with next socket() bind() connect() */
      } else
#endif /* WITH_RETRY */
      {
	 break;
      }
#if 0
      if ((result = _xio_openlate(fd, opts)) < 0)
	 return result;
#endif
   } while (true);

   return 0;
}


/* common to xioopen_udp_sendto, ..unix_sendto, ..rawip
   applies and consumes the following option:
   PH_PASTSOCKET, PH_FD, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_CONNECTED, PH_LATE
   OFUNC_OFFSET
   OPT_SO_TYPE, OPT_SO_PROTOTYPE, OPT_USER, OPT_GROUP, OPT_CLOEXEC
   returns the resulting FD in xfd->rfd, independend of xioflags
 */
int _xioopen_dgram_sendto(/* them is already in xfd->peersa */
			union sockaddr_union *us, socklen_t uslen,
			struct opt *opts,
			int xioflags, xiosingle_t *xfd, unsigned groups,
			int pf, int socktype, int ipproto) {
   int level = E_ERROR;
   union sockaddr_union la; socklen_t lalen = sizeof(la);
   char infobuff[256];

   if ((xfd->rfd = xiosocket(opts, pf, socktype, ipproto, level)) < 0) {
      return STAT_RETRYLATER;	    
   }

   applyopts_offset(xfd, opts);
   applyopts_single(xfd, opts, PH_PASTSOCKET);
   applyopts(xfd->rfd, opts, PH_PASTSOCKET);
   applyopts(xfd->rfd, opts, PH_FD);

   applyopts_cloexec(xfd->rfd, opts);

   applyopts(xfd->rfd, opts, PH_PREBIND);
   applyopts(xfd->rfd, opts, PH_BIND);

   if (us) {
      if (Bind(xfd->rfd, (struct sockaddr *)us, uslen) < 0) {
	 Msg4(level, "bind(%d, {%s}, "F_Zd"): %s",
	      xfd->rfd, sockaddr_info((struct sockaddr *)us, uslen, infobuff, sizeof(infobuff)),
	      uslen, strerror(errno));
	 Close(xfd->rfd);
	 return STAT_RETRYLATER;
      }
   }

   applyopts(xfd->rfd, opts, PH_PASTBIND);

   /*applyopts(xfd->rfd, opts, PH_CONNECT);*/

   if (Getsockname(xfd->rfd, &la.soa, &lalen) < 0) {
      Warn4("getsockname(%d, %p, {%d}): %s",
	    xfd->rfd, &la.soa, lalen, strerror(errno));
   }

   applyopts_fchown(xfd->rfd, opts);
   applyopts(xfd->rfd, opts, PH_CONNECTED);
   applyopts(xfd->rfd, opts, PH_LATE);

   /* xfd->dtype = DATA_RECVFROM; *//* no, the caller must set this (ev _SKIPIP) */
   Notice1("successfully prepared local socket %s",
	   sockaddr_info(&la.soa, lalen, infobuff, sizeof(infobuff)));

   return STAT_OK;
}


/* when the recvfrom address (with option fork) receives a packet it keeps this
   packet in the IP stacks input queue and forks a sub process. The sub process
   then reads this packet for processing its data.
   There is a problem because the parent process would find the same packet
   again if it calls select()/poll() before the child process reads the
   packet.
   To solve this problem we implement the following mechanism:
   The sub process sends a SIGUSR1 when it has read the packet (or a SIGCHLD if
   it dies before). The parent process waits until it receives that signal and
   only then continues to listen.
   To prevent a signal from another process to trigger our loop, we pass the
   pid of the sub process to the signal handler in xio_waitingfor. The signal
   handler sets xio_hashappened if the pid matched.
*/
static pid_t xio_waitingfor;	/* info from recv loop to signal handler:
				   indicates the pid that of the child process
				   that should send us the USR1 signal */
static bool xio_hashappened;	/* info from signal handler to loop: child
				   process has read ("consumed") the packet */
/* this is the signal handler for USR1 and CHLD */
void xiosigaction_hasread(int signum
#if HAVE_STRUCT_SIGACTION_SA_SIGACTION && defined(SA_SIGINFO)
			  , siginfo_t *siginfo, void *ucontext
#endif
			  ) {
   pid_t pid;
   int _errno;
   int status = 0;
   bool wassig = false;
#if HAVE_STRUCT_SIGACTION_SA_SIGACTION && defined(SA_SIGINFO)
   Debug5("xiosigaction_hasread(%d, {%d,%d,%d,"F_pid"}, )",
	  signum, siginfo->si_signo, siginfo->si_errno, siginfo->si_code,
	  siginfo->si_pid);
#else
   Debug1("xiosigaction_hasread(%d)", signum);
#endif
   if (signum == SIGCHLD) {
      _errno = errno;
      do {
	 pid = Waitpid(-1, &status, WNOHANG);
	 if (pid == 0) {
	    Msg(wassig?E_INFO:E_WARN,
		"waitpid(-1, {}, WNOHANG): no child has exited");
	    Info("xiosigaction_hasread() finished");
	    errno = _errno;
	    Debug("xiosigaction_hasread() ->");
	    return;
	 } else if (pid < 0 && errno == ECHILD) {
	    Msg1(wassig?E_INFO:E_WARN,
		 "waitpid(-1, {}, WNOHANG): %s", strerror(errno));
	    Info("xiosigaction_hasread() finished");
	    errno = _errno;
	    Debug("xiosigaction_hasread() ->");
	    return;
	 }
	 wassig = true;
	 if (pid < 0) {
	    Warn2("waitpid(-1, {%d}, WNOHANG): %s", status, strerror(errno));
	    Info("xiosigaction_hasread() finished");
	    errno = _errno;
	    Debug("xiosigaction_hasread() ->");
	    return;
	 }
	 if (pid == xio_waitingfor) {
	    xio_hashappened = true;
	    Debug("xiosigaction_hasread() ->");
	    return;
	 }
      } while (1);
   }
#if HAVE_STRUCT_SIGACTION_SA_SIGACTION && defined(SA_SIGINFO)
   if (xio_waitingfor == siginfo->si_pid) {
      xio_hashappened = true;
   }
#else
   xio_hashappened = true;
#endif
   Debug("xiosigaction_hasread() ->");
   return;
}


/* waits for incoming packet, checks its source address and port. Depending
   on fork option, it may fork a subprocess.
   Returns STAT_OK if a the packet was accepted; with fork option, this is already in
   a new subprocess!
   Other return values indicate a problem; this can happen in the master
   process or in a subprocess.
   This function does not retry. If you need retries, handle this is a
   loop in the calling function.
   after fork, we set the forever/retry of the child process to 0
   applies and consumes the following options: 
   PH_INIT, PH_PREBIND, PH_BIND, PH_PASTBIND, PH_EARLY, PH_PREOPEN, PH_FD,
   PH_CONNECTED, PH_LATE, PH_LATE2
   OPT_FORK, OPT_SO_TYPE, OPT_SO_PROTOTYPE, cloexec, OPT_RANGE, tcpwrap
 */
int _xioopen_dgram_recvfrom(struct single *xfd, int xioflags,
			  struct sockaddr *us, socklen_t uslen,
			  struct opt *opts,
			  int pf, int socktype, int proto, int level) {
   int rw = (xioflags&XIO_ACCMODE);
   int s;
   char *rangename;
   bool dofork = false;
   pid_t pid;	/* mostly int; only used with fork */
   char infobuff[256];
   char lisname[256];
   bool drop = false;	/* true if current packet must be dropped */
   int result;

   retropt_bool(opts, OPT_FORK, &dofork);

   if (dofork) {
      if (!(xioflags & XIO_MAYFORK)) {
	 Error("option fork not allowed here");
	 return STAT_NORETRY;
      }
      xfd->flags |= XIO_DOESFORK;
   }

   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return STAT_NORETRY;

#if 1
   if (dofork) {
#if HAVE_SIGACTION
      struct sigaction act;
      memset(&act, 0, sizeof(struct sigaction));
      act.sa_flags   = SA_NOCLDSTOP|SA_RESTART
#ifdef SA_NOMASK
	 |SA_NOMASK
#endif
	 ;
#if HAVE_SIGACTION
      act.sa_sigaction = childdied;
#else
      act.sa_handler = childdied;
#endif
      if (Sigaction(SIGCHLD, &act, NULL) < 0) {
	 /*! man does not say that errno is defined */
	 Warn2("sigaction(SIGCHLD, %p, NULL): %s", childdied, strerror(errno));
      }
#else /* HAVE_SIGACTION */
      if (Signal(SIGCHLD, childdied) == SIG_ERR) {
	 Warn2("signal(SIGCHLD, %p): %s", childdied, strerror(errno));
      }
#endif /* !HAVE_SIGACTION */
   }
#endif /* 1 */

   if ((s = xiosocket(opts, pf, socktype, proto, level)) < 0) {
      return STAT_RETRYLATER;
   }
   if (XIOWITHRD(rw))  xfd->rfd = s;
   if (XIOWITHWR(rw))  xfd->wfd = s;

   applyopts_single(xfd, opts, PH_PASTSOCKET);
   applyopts(xfd->rfd, opts, PH_PASTSOCKET);

   applyopts_cloexec(xfd->rfd, opts);

   applyopts(xfd->rfd, opts, PH_PREBIND);
   applyopts(xfd->rfd, opts, PH_BIND);
   if ((us != NULL) && Bind(xfd->rfd, (struct sockaddr *)us, uslen) < 0) {
      Msg4(level, "bind(%d, {%s}, "F_Zd"): %s", xfd->rfd,
	   sockaddr_info(us, uslen, infobuff, sizeof(infobuff)), uslen,
	   strerror(errno));
      Close(xfd->rfd);
      return STAT_RETRYLATER;
   }

#if WITH_UNIX
   if (pf == AF_UNIX && us != NULL) {
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_FD);
   }
#endif

   applyopts(xfd->rfd, opts, PH_PASTBIND);
#if WITH_UNIX
   if (pf == AF_UNIX && us != NULL) {
      /*applyopts_early(((struct sockaddr_un *)us)->sun_path, opts);*/
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_EARLY);
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_PREOPEN);
   }
#endif /* WITH_UNIX */

   /* for generic sockets, this has already been retrieved */
   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, pf, &xfd->para.socket.range)
	  < 0) {
	 free(rangename);
	 return STAT_NORETRY;
      }
      free(rangename);
      xfd->para.socket.dorange = true;
   }

#if (WITH_TCP || WITH_UDP) && WITH_LIBWRAP
   xio_retropt_tcpwrap(xfd, opts);
#endif /* && (WITH_TCP || WITH_UDP) && WITH_LIBWRAP */

   if (xioopts.logopt == 'm') {
      Info("starting recvfrom loop, switching to syslog");
      diag_set('y', xioopts.syslogfac);  xioopts.logopt = 'y';
   } else {
      Info("starting recvfrom loop");
   }

   if (dofork) {
#if HAVE_SIGACTION
   {
      struct sigaction act;
      memset(&act, 0, sizeof(struct sigaction));
      act.sa_flags   = SA_NOCLDSTOP|SA_RESTART
#ifdef SA_SIGINFO /* not on Linux 2.0(.33) */
	 |SA_SIGINFO
#endif
#ifdef SA_NOMASK
         |SA_NOMASK
#endif
         ;
#if HAVE_STRUCT_SIGACTION_SA_SIGACTION && defined(SA_SIGINFO)
      act.sa_sigaction = xiosigaction_hasread;
#else /* Linux 2.0(.33) does not have sigaction.sa_sigaction */
      act.sa_handler = xiosigaction_hasread;
#endif
      if (Sigaction(SIGUSR1, &act, NULL) < 0) {
         /*! Linux man does not explicitely say that errno is defined */
         Warn1("sigaction(SIGUSR1, {&xiosigaction_subaddr_ok}, NULL): %s", strerror(errno));
      }
      if (Sigaction(SIGCHLD, &act, NULL) < 0) {
         /*! Linux man does not explicitely say that errno is defined */
         Warn1("sigaction(SIGCHLD, {&xiosigaction_subaddr_ok}, NULL): %s", strerror(errno));
      }
   }
#else /* !HAVE_SIGACTION */
   /*!!!*/
      if (Signal(SIGUSR1, xiosigaction_hasread) == SIG_ERR) {
	 Warn1("signal(SIGUSR1, xiosigaction_hasread): %s", strerror(errno));
      }
      if (Signal(SIGCHLD, xiosigaction_hasread) == SIG_ERR) {
	 Warn1("signal(SIGCHLD, xiosigaction_hasread): %s", strerror(errno));
      }
#endif /* !HAVE_SIGACTION */
   }

   while (true) {	/* but we only loop if fork option is set */
      char peername[256];
      union sockaddr_union _peername;
      union sockaddr_union _sockname;
      union sockaddr_union *pa = &_peername;	/* peer address */
      union sockaddr_union *la = &_sockname;	/* local address */
      socklen_t palen = sizeof(_peername);	/* peer address size */
      char ctrlbuff[1024];			/* ancillary messages */
      struct msghdr msgh = {0};

      socket_init(pf, pa);

      if (drop) {
	 char *dummy[2];

	 Recv(xfd->rfd, dummy, sizeof(dummy), 0);
	 drop = true;
      }

      /* loop until select()/poll() returns valid */
      do {
	 struct pollfd readfd;
	 /*? int level = E_ERROR;*/
	 if (us != NULL) {
	    Notice1("receiving on %s", sockaddr_info(us, uslen, lisname, sizeof(lisname)));
	 } else {
	    Notice1("receiving IP protocol %u", proto);
	 }
	 readfd.fd = xfd->rfd;
	 readfd.events = POLLIN;
	 if (xiopoll(&readfd, 1, NULL) > 0) {
	    break;
	 }

	 if (errno == EINTR) {
	    continue;
	 }

	 Msg2(level, "xiopoll({%d,,},,-1): %s", xfd->rfd, strerror(errno));
	 Close(xfd->rfd);
	 return STAT_RETRYLATER;
      } while (true);

      msgh.msg_name = pa;
      msgh.msg_namelen = palen;
#if HAVE_STRUCT_MSGHDR_MSGCONTROL
      msgh.msg_control = ctrlbuff;
#endif
#if HAVE_STRUCT_MSGHDR_MSGCONTROLLEN
      msgh.msg_controllen = sizeof(ctrlbuff);
#endif
      if (xiogetpacketsrc(xfd->rfd, &msgh) < 0) {
	 return STAT_RETRYLATER;
      }
      palen = msgh.msg_namelen;

      Notice1("receiving packet from %s"/*"src"*/,
	      sockaddr_info((struct sockaddr *)pa, palen, peername, sizeof(peername))/*,
							     sockaddr_info(&la->soa, sockname, sizeof(sockname))*/);

      xiodopacketinfo(&msgh, true, true);

      if (xiocheckpeer(xfd, pa, la) < 0) {
	 /* drop packet */
	 char buff[512];
	 Recv(xfd->rfd, buff, sizeof(buff), 0);
	 continue;
      }
      Info1("permitting packet from %s",
	    sockaddr_info((struct sockaddr *)pa, palen,
			  infobuff, sizeof(infobuff)));

      /* set the env vars describing the local and remote sockets */
      /*xiosetsockaddrenv("SOCK", la, lalen, proto);*/
      xiosetsockaddrenv("PEER", pa, palen, proto);

      applyopts(xfd->rfd, opts, PH_FD);

      applyopts(xfd->rfd, opts, PH_CONNECTED);

      xfd->peersa = *(union sockaddr_union *)pa;
      xfd->salen = palen;

      if (dofork) {
	 sigset_t mask_sigchldusr1;

	 /* we must prevent that the current packet triggers another fork;
	    therefore we wait for a signal from the recent child: USR1
	    indicates that is has consumed the last packet; CHLD means it has
	    terminated */
	 /* block SIGCHLD and SIGUSR1 until parent is ready to react */
	 sigemptyset(&mask_sigchldusr1);
	 sigaddset(&mask_sigchldusr1, SIGCHLD);
	 sigaddset(&mask_sigchldusr1, SIGUSR1);
	 Sigprocmask(SIG_BLOCK, &mask_sigchldusr1, NULL);

	 if ((pid = xio_fork(false, level)) < 0) {
	    Close(xfd->rfd);
	    Sigprocmask(SIG_UNBLOCK, &mask_sigchldusr1, NULL);
	    return STAT_RETRYLATER;
	 }

	 if (pid == 0) {	/* child */
	    /* no reason to block SIGCHLD in child process */
	    Sigprocmask(SIG_UNBLOCK, &mask_sigchldusr1, NULL);
	    xfd->ppid = Getppid();	/* send parent a signal when packet has
					   been consumed */

#if WITH_RETRY
	    /* !? */
	    xfd->retry = 0;
	    xfd->forever = 0;
	    level = E_ERROR;
#endif /* WITH_RETRY */

#if WITH_UNIX
	    /* with UNIX sockets: only listening parent is allowed to remove
	       the socket file */
	    xfd->opt_unlink_close = false;
#endif /* WITH_UNIX */

	    break;
	 }

	 /* server: continue loop with listen */
	 xio_waitingfor = pid;
	 /* now we are ready to handle signals */
	 Sigprocmask(SIG_UNBLOCK, &mask_sigchldusr1, NULL);

	 while (!xio_hashappened) {
	    Sleep(UINT_MAX);	/* any signal lets us continue */
	 }
	 xio_waitingfor = 0;	/* so this child will not set hashappened again */
	 xio_hashappened = false;

	 Info("continue listening");
      } else {
	break;
      }
   }
   if ((result = _xio_openlate(xfd, opts)) != 0)
      return STAT_NORETRY;

   return STAT_OK;
}


/* returns STAT_* */
int _xioopen_dgram_recv(struct single *xfd, int xioflags,
			struct sockaddr *us, socklen_t uslen,
			struct opt *opts, int pf, int socktype, int proto,
			int level) {
   int rw = (xioflags&XIO_ACCMODE);
   int s;
   char *rangename;
   char infobuff[256];

   if (applyopts_single(xfd, opts, PH_INIT) < 0)  return STAT_NORETRY;

   if ((s = xiosocket(opts, pf, socktype, proto, level)) < 0) {
      return STAT_RETRYLATER;
   }
   if (XIOWITHRD(rw))  xfd->rfd = s;
   if (XIOWITHWR(rw))  xfd->wfd = s;

   applyopts_single(xfd, opts, PH_PASTSOCKET);
   applyopts(xfd->rfd, opts, PH_PASTSOCKET);

   applyopts_cloexec(xfd->rfd, opts);

   applyopts(xfd->rfd, opts, PH_PREBIND);
   applyopts(xfd->rfd, opts, PH_BIND);
   if ((us != NULL) && Bind(xfd->rfd, (struct sockaddr *)us, uslen) < 0) {
      Msg4(level, "bind(%d, {%s}, "F_Zd"): %s", xfd->rfd,
	   sockaddr_info(us, uslen, infobuff, sizeof(infobuff)), uslen,
	   strerror(errno));
      Close(xfd->rfd);
      return STAT_RETRYLATER;
   }

#if WITH_UNIX
   if (pf == AF_UNIX && us != NULL) {
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_FD);
   }
#endif

   applyopts(xfd->rfd, opts, PH_PASTBIND);
#if WITH_UNIX
   if (pf == AF_UNIX && us != NULL) {
      /*applyopts_early(((struct sockaddr_un *)us)->sun_path, opts);*/
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_EARLY);
      applyopts_named(((struct sockaddr_un *)us)->sun_path, opts, PH_PREOPEN);
   }
#endif /* WITH_UNIX */

#if WITH_IP4 /*|| WITH_IP6*/
   if (retropt_string(opts, OPT_RANGE, &rangename) >= 0) {
      if (xioparserange(rangename, pf, &xfd->para.socket.range)
	  < 0) {
	 free(rangename);
	 return STAT_NORETRY;
      }
      free(rangename);
      xfd->para.socket.dorange = true;
   }
#endif

#if (WITH_TCP || WITH_UDP) && WITH_LIBWRAP
   xio_retropt_tcpwrap(xfd, opts);
#endif /* && (WITH_TCP || WITH_UDP) && WITH_LIBWRAP */

   if (xioopts.logopt == 'm') {
      Info("starting recvfrom loop, switching to syslog");
      diag_set('y', xioopts.syslogfac);  xioopts.logopt = 'y';
   } else {
      Info("starting recvfrom loop");
   }

   return STAT_OK;
}


int retropt_socket_pf(struct opt *opts, int *pf) {
   char *pfname;

   if (retropt_string(opts, OPT_PROTOCOL_FAMILY, &pfname) >= 0) {
      if (isdigit(pfname[0])) {
	 *pf = strtoul(pfname, NULL /*!*/, 0);
#if WITH_IP4
      } else if (!strcasecmp("inet", pfname) ||
	  !strcasecmp("inet4", pfname) ||
	  !strcasecmp("ip4", pfname) ||
	  !strcasecmp("ipv4", pfname) ||
	  !strcasecmp("2", pfname)) {
	 *pf = PF_INET;
#endif /* WITH_IP4 */
#if WITH_IP6
      } else if (!strcasecmp("inet6", pfname) ||
		 !strcasecmp("ip6", pfname) ||
		 !strcasecmp("ipv6", pfname) ||
		 !strcasecmp("10", pfname)) {
	 *pf = PF_INET6;
#endif /* WITH_IP6 */
      } else {
	 Error1("unknown protocol family \"%s\"", pfname);
	 /*! Warn("falling back to INET");*/
      }
      free(pfname);
      return 0;
   }
   return -1;
}


/* this function calls recvmsg(..., MSG_PEEK, ...) to obtain information about
   the arriving packet. in msgh the msg_name pointer must refer to an (empty)
   sockaddr storage. */
int xiogetpacketsrc(int fd, struct msghdr *msgh) {
   char peekbuff[1];
#if HAVE_STRUCT_IOVEC
   struct iovec iovec;
#endif

#if HAVE_STRUCT_IOVEC
   iovec.iov_base = peekbuff;
   iovec.iov_len  = sizeof(peekbuff);
   msgh->msg_iov = &iovec;
   msgh->msg_iovlen = 1;
#endif
#if HAVE_STRUCT_MSGHDR_MSGFLAGS
   msgh->msg_flags = 0;
#endif
   if (Recvmsg(fd, msgh, MSG_PEEK
#ifdef MSG_TRUNC
		 |MSG_TRUNC
#endif
	       ) < 0) {
      Warn1("recvmsg(): %s", strerror(errno));
      return STAT_RETRYLATER;
   }
   return STAT_OK;
}


/* works through the ancillary messages found in the given socket header record
   and logs the relevant information (E_DEBUG, E_INFO).
   calls protocol/layer specific functions for handling the messages
   creates appropriate environment vars if withenv is set */
int xiodopacketinfo(struct msghdr *msgh, bool withlog, bool withenv) {
#if defined(HAVE_STRUCT_CMSGHDR) && defined(CMSG_DATA)
   struct cmsghdr *cmsg;

   /* parse ancillary messages */
   cmsg = CMSG_FIRSTHDR(msgh);
   while (cmsg != NULL) {
      int num = 0;	/* number of data components of a ancill.msg */
      int i;
      char typbuff[16],  *typp;
      char nambuff[128], *namp;
      char valbuff[256], *valp;
      char envbuff[256], *envp;

      if (withlog) {
	 xiodump(CMSG_DATA(cmsg),
		 cmsg->cmsg_len-((char *)CMSG_DATA(cmsg)-(char *)cmsg),
		 valbuff, sizeof(valbuff)-1, 0);
	 Debug4("ancillary message: len="F_socklen", level=%d, type=%d, data=%s",
		cmsg->cmsg_len, cmsg->cmsg_level, cmsg->cmsg_type,
		valbuff);
      }

      /* try to get the anc.msg. contents in handy components, protocol/level
	 dependent */
      switch (cmsg->cmsg_level) {
      case SOL_SOCKET:
	 xiolog_ancillary_socket(cmsg, &num, typbuff, sizeof(typbuff)-1,
				 nambuff, sizeof(nambuff)-1,
				 envbuff, sizeof(envbuff)-1,
				 valbuff, sizeof(valbuff)-1);
	 break;
#if WITH_IP4 || WITH_IP6
      case SOL_IP:
	 xiolog_ancillary_ip(cmsg, &num, typbuff, sizeof(typbuff)-1,
			     nambuff, sizeof(nambuff)-1,
			     envbuff, sizeof(envbuff)-1,
			     valbuff, sizeof(valbuff)-1);
	 break;
#endif /* WITH_IP4 || WITH_IP6 */
#if WITH_IP6
      case SOL_IPV6:
	 xiolog_ancillary_ip6(cmsg, &num, typbuff, sizeof(typbuff)-1,
			      nambuff, sizeof(nambuff)-1,
			      envbuff, sizeof(envbuff)-1,
			      valbuff, sizeof(valbuff)-1);
	 break;
#endif /* WITH_IP6 */
      default:
	 num = 1;
	 snprintf(typbuff, sizeof(typbuff)-1, "LEVEL%u", cmsg->cmsg_level);
	 snprintf(nambuff, sizeof(nambuff)-1, "type%u", cmsg->cmsg_type);
	 xiodump(CMSG_DATA(cmsg),
		 cmsg->cmsg_len-((char *)CMSG_DATA(cmsg)-(char *)cmsg),
		 valbuff, sizeof(valbuff)-1, 0);
      }
      /* here the info is in typbuff (one string), nambuff (num consecutive
	 strings), and valbuff (num consecutive strings) */
      i = 0;
      typp = typbuff;  namp = nambuff;  envp = envbuff;  valp = valbuff;
      while (i < num) {
	 if (withlog) {
	    Info3("ancillary message: %s: %s=%s", typp, namp, valp);
	 }
	 if (withenv) {
	    if (*envp) {
	       xiosetenv(envp, valp, 1);
	    } else if (!strcasecmp(typp+strlen(typp)-strlen(namp), namp)) {
	       xiosetenv(typp, valp, 1);
	    } else	{
	       xiosetenv2(typp, namp, valp, 1);
	    }
	 }
	 if (++i == num)  break;
	 namp = strchr(namp, '\0')+1;
	 envp = strchr(envp, '\0')+1;
	 valp = strchr(valp, '\0')+1;
      }
      cmsg = CMSG_NXTHDR(msgh, cmsg);
   }
   return 0;
#else /* !(defined(HAVE_STRUCT_CMSGHDR) && defined(CMSG_DATA)) */
   return -1;
#endif /* !(defined(HAVE_STRUCT_CMSGHDR) && defined(CMSG_DATA)) */
}


/* check if peer address is within permitted range.
   return >= 0 if so. */
int xiocheckrange(union sockaddr_union *sa, struct xiorange *range) {
   switch (sa->soa.sa_family) {
#if WITH_IP4
   case PF_INET:
      return
	 xiocheckrange_ip4(&sa->ip4, range);
#endif /* WITH_IP4 */
#if WITH_IP6
   case PF_INET6:
      return
	 xiocheckrange_ip6(&sa->ip6, range);
#endif /* WITH_IP6 */
#if 0
   case PF_UNSPEC:
     {
      socklen_t i;
      for (i = 0; i < sizeof(sa->soa.sa_data); ++i) {
	 if ((range->netmask.soa.sa_data[i] & sa->soa.sa_data[i]) != range->netaddr.soa.sa_data[i]) {
	    return -1;
	 }
      }
      return 0;
     }
#endif
   }
   return -1;
}

int xiocheckpeer(xiosingle_t *xfd,
		 union sockaddr_union *pa, union sockaddr_union *la) {
   char infobuff[256];
   int result;

#if WITH_IP4
   if (xfd->para.socket.dorange) {
      if (pa == NULL)  { return -1; }
      if (xiocheckrange(pa, &xfd->para.socket.range) < 0) {
	 char infobuff[256];
	 Warn1("refusing connection from %s due to range option",
	       sockaddr_info((struct sockaddr *)pa, 0,
			     infobuff, sizeof(infobuff)));
	 return -1;
      }
      Info1("permitting connection from %s due to range option",
	    sockaddr_info((struct sockaddr *)pa, 0,
			  infobuff, sizeof(infobuff)));
   }
#endif /* WITH_IP4 */

#if WITH_TCP || WITH_UDP
   if (xfd->para.socket.ip.dosourceport) {
      if (pa == NULL)  { return -1; }
#if WITH_IP4
      if (pa->soa.sa_family == AF_INET &&
	  ntohs(((struct sockaddr_in *)pa)->sin_port) != xfd->para.socket.ip.sourceport) {
	 Warn1("refusing connection from %s due to wrong sourceport",
	       sockaddr_info((struct sockaddr *)pa, 0,
			     infobuff, sizeof(infobuff)));
	 return -1;
      }
#endif /* WITH_IP4 */
#if WITH_IP6
      if (pa->soa.sa_family == AF_INET6 &&
	  ntohs(((struct sockaddr_in6 *)pa)->sin6_port) != xfd->para.socket.ip.sourceport) {
	 Warn1("refusing connection from %s due to wrong sourceport",
	       sockaddr_info((struct sockaddr *)pa, 0,
			     infobuff, sizeof(infobuff)));
	 return -1;
      }
#endif /* WITH_IP6 */
      Info1("permitting connection from %s due to sourceport option",
	    sockaddr_info((struct sockaddr *)pa, 0,
			  infobuff, sizeof(infobuff)));
   } else if (xfd->para.socket.ip.lowport) {
      if (pa == NULL)  { return -1; }
      if (pa->soa.sa_family == AF_INET &&
	  ntohs(((struct sockaddr_in *)pa)->sin_port) >= IPPORT_RESERVED) {
	 Warn1("refusing connection from %s due to lowport option",
	       sockaddr_info((struct sockaddr *)pa, 0,
			     infobuff, sizeof(infobuff)));
	 return -1;
      }
#if WITH_IP6
      else if (pa->soa.sa_family == AF_INET6 &&
	       ntohs(((struct sockaddr_in6 *)pa)->sin6_port) >=
	       IPPORT_RESERVED) {
	 Warn1("refusing connection from %s due to lowport option",
	       sockaddr_info((struct sockaddr *)pa, 0,
			     infobuff, sizeof(infobuff)));
	 return -1;
      }
#endif /* WITH_IP6 */
      Info1("permitting connection from %s due to lowport option",
	    sockaddr_info((struct sockaddr *)pa, 0,
			  infobuff, sizeof(infobuff)));
   }
#endif /* WITH_TCP || WITH_UDP */

#if (WITH_TCP || WITH_UDP) && WITH_LIBWRAP
   result = xio_tcpwrap_check(xfd, la, pa);
   if (result < 0) {
      char infobuff[256];
      Warn1("refusing connection from %s due to tcpwrapper option",
	    sockaddr_info((struct sockaddr *)pa, 0,
			  infobuff, sizeof(infobuff)));
      return -1;
   } else if (result > 0) {
      Info1("permitting connection from %s due to tcpwrapper option",
	    sockaddr_info((struct sockaddr *)pa, 0,
			  infobuff, sizeof(infobuff)));
   }
#endif /* (WITH_TCP || WITH_UDP) && WITH_LIBWRAP */

   return 0;	/* permitted */
}


#if HAVE_STRUCT_CMSGHDR
/* converts the ancillary message in *cmsg into a form useable for further
   processing. knows the specifics of common message types.
   returns the number of resulting syntax elements in *num
   returns a sequence of \0 terminated type strings in *typbuff
   returns a sequence of \0 terminated name strings in *nambuff
   returns a sequence of \0 terminated value strings in *valbuff
   the respective len parameters specify the available space in the buffers
   returns STAT_OK or other STAT_*
 */
static int
xiolog_ancillary_socket(struct cmsghdr *cmsg, int *num,
			char *typbuff, int typlen,
			char *nambuff, int namlen,
			char *envbuff, int envlen,
			char *valbuff, int vallen) {
   const char *cmsgtype, *cmsgname, *cmsgenvn;
   size_t msglen;
   struct timeval *tv;
   int rc = STAT_OK;

#if defined(CMSG_DATA)

   msglen = cmsg->cmsg_len-((char *)CMSG_DATA(cmsg)-(char *)cmsg);
   switch (cmsg->cmsg_type) {
#ifdef SO_PASSCRED
   case SO_PASSCRED:	/* this is really a UNIX/LOCAL message */
      /*! needs implementation */
#endif /* SO_PASSCRED */
#ifdef SO_RIGHTS
   case SO_RIGHTS:	/* this is really a UNIX/LOCAL message */
      /*! needs implementation */
#endif
   default:	/* binary data */
      snprintf(typbuff, typlen, "SOCKET.%u", cmsg->cmsg_type);
      nambuff[0] = '\0'; strncat(nambuff, "data", namlen-1);
      xiodump(CMSG_DATA(cmsg), msglen, valbuff, vallen, 0);
      return STAT_OK;
#ifdef SO_TIMESTAMP
#  ifdef SCM_TIMESTAMP
   case SCM_TIMESTAMP:
#  else
   case SO_TIMESTAMP:
#  endif
      tv = (struct timeval *)CMSG_DATA(cmsg);
      cmsgtype =
#ifdef SCM_TIMESTAMP
	 "SCM_TIMESTAMP"	/* FreeBSD */
#else
	 "SO_TIMESTAMP"		/* Linux */
#endif
	    ;
      cmsgname = "timestamp";
      cmsgenvn = "TIMESTAMP";
      { time_t t = tv->tv_sec; ctime_r(&t, valbuff); }
      snprintf(strchr(valbuff, '\0')-1/*del \n*/, vallen-strlen(valbuff)+1, ", %06ld usecs", (long)tv->tv_usec);
      break;
#endif /* defined(SO_TIMESTAMP) */
      ;
   }
   /* when we come here we provide a single parameter
      with type in cmsgtype, name in cmsgname,
      and value already in valbuff */
   *num = 1;
   if (strlen(cmsgtype) >= typlen)  rc = STAT_WARNING;
   typbuff[0] = '\0'; strncat(typbuff, cmsgtype, typlen-1);
   if (strlen(cmsgname) >= namlen)  rc = STAT_WARNING;
   nambuff[0] = '\0'; strncat(nambuff, cmsgname, namlen-1);
   if (strlen(cmsgenvn) >= envlen)  rc = STAT_WARNING;
   envbuff[0] = '\0'; strncat(envbuff, cmsgenvn, envlen-1);
   return rc;
#else /* !defined(CMSG_DATA) */

   return STAT_NORETRY;

#endif /* !defined(CMSG_DATA) */
}
#endif /* HAVE_STRUCT_CMSGHDR */


/* return the name of the interface with given index
   or NULL if is fails
   The system call requires an arbitrary socket; the calling program may
   provide one in parameter ins to avoid creation of a dummy socket. ins must
   be <0 if it does not specify a socket fd. */
char *xiogetifname(int ind, char *val, int ins) {
#if !HAVE_IF_INDEXTONAME
   int s;
   struct ifreq ifr;

   if (ins >= 0) {
      s = ins;
   } else {
      if ((s = Socket(PF_INET, SOCK_DGRAM, IPPROTO_IP)) < 0) {
	 Error1("socket(PF_INET, SOCK_DGRAM, IPPROTO_IP): %s", strerror(errno));
	 return NULL;
      }
   }

#if HAVE_STRUCT_IFREQ_IFR_INDEX
   ifr.ifr_index = ind;
#elif HAVE_STRUCT_IFREQ_IFR_IFINDEX
   ifr.ifr_ifindex = ind;
#endif
#ifdef SIOCGIFNAME
   if(Ioctl(s, SIOCGIFNAME, &ifr) < 0) {
#if HAVE_STRUCT_IFREQ_IFR_INDEX
      Info3("ioctl(%d, SIOCGIFNAME, {..., ifr_index=%d, ...}: %s",
	    s, ifr.ifr_index, strerror(errno));
#elif HAVE_STRUCT_IFREQ_IFR_IFINDEX
      Info3("ioctl(%d, SIOCGIFNAME, {..., ifr_ifindex=%d, ...}: %s",
	    s, ifr.ifr_ifindex, strerror(errno));
#endif
      if (ins < 0)  Close(s);
      return NULL;
   }
#endif /* SIOCGIFNAME */
   if (ins < 0)  Close(s);
   strcpy(val, ifr.ifr_name);
   return val;
#else /* HAVE_IF_INDEXTONAME */
   return if_indextoname(ind, val);
#endif /* HAVE_IF_INDEXTONAME */
}


/* parses a network specification consisting of an address and a mask. */
int xioparsenetwork(const char *rangename, int pf, struct xiorange *range) {
   size_t addrlen = 0, masklen = 0;
   int result;

  switch (pf) {
#if WITH_IP4
  case PF_INET:
      return xioparsenetwork_ip4(rangename, range);
   break;
#endif /* WITH_IP4 */
#if WITH_IP6
   case PF_INET6:
      return xioparsenetwork_ip6(rangename, range);
      break;
#endif /* WITH_IP6 */
  case PF_UNSPEC:
    {
     char *addrname;
     const char *maskname;
     if ((maskname = strchr(rangename, ':')) == NULL) {
	Error1("syntax error in range \"%s\": use <addr>:<mask>", rangename);
	return STAT_NORETRY;
     }
     ++maskname;	/* skip ':' */
     if ((addrname = Malloc(maskname-rangename)) == NULL) {
	return STAT_NORETRY;
     }
     strncpy(addrname, rangename, maskname-rangename-1);	/* ok */
     addrname[maskname-rangename-1] = '\0';
     result =
	dalan(addrname, (char *)&range->netaddr.soa.sa_data, &addrlen,
	      sizeof(range->netaddr)-(size_t)(&((struct sockaddr *)0)->sa_data)
	      /* data length */);
     if (result < 0) {
	Error1("data too long: \"%s\"", addrname);
	free(addrname); return STAT_NORETRY;
     } else if (result > 0) {
	Error1("syntax error in \"%s\"", addrname);
	free(addrname); return STAT_NORETRY;
     }
     free(addrname); 
     result =
	dalan(maskname, (char *)&range->netmask.soa.sa_data, &masklen,
	      sizeof(range->netaddr)-(size_t)(&((struct sockaddr *)0)->sa_data)
	      /* data length */);
     if (result < 0) {
	Error1("data too long: \"%s\"", maskname);
	return STAT_NORETRY;
     } else if (result > 0) {
	Error1("syntax error in \"%s\"", maskname);
	return STAT_NORETRY;
     }
	 if (addrlen != masklen) {
	    Error2("network address is "F_Zu" bytes long, mask is "F_Zu" bytes long",
		   addrlen, masklen);
	    /* recover by padding the shorter component with 0 */
	    memset((char *)&range->netaddr.soa.sa_data+addrlen, 0,
		   MAX(0, addrlen-masklen));
	    memset((char *)&range->netmask.soa.sa_data+masklen, 0,
		   MAX(0, masklen-addrlen));
	 }
    }
    break;
  default:
     Error1("range option not supported with address family %d", pf);
     return STAT_NORETRY;
  }
  return STAT_OK;
}


/* parses a string of form address/bits or address:mask, and fills the fields 
   of the range union. The addr component is masked with mask. */
int xioparserange(const char *rangename, int pf, struct xiorange *range) {
   int i;
   if (xioparsenetwork(rangename, pf, range) < 0) {
      return -1;
   }
   /* we have parsed the address and mask; now we make sure that the stored
      address has 0 where mask is 0, to simplify comparisions */
   switch (pf) {
#if WITH_IP4
   case PF_INET:
      range->netaddr.ip4.sin_addr.s_addr &= range->netmask.ip4.sin_addr.s_addr;
      break;
#endif /* WITH_IP4 */
#if WITH_IP6
   case PF_INET6:
      return xiorange_ip6andmask(range);
      break;
#endif /* WITH_IP6 */
   case PF_UNSPEC:
      for (i = 0; i < sizeof(range->netaddr); ++i) {
	 ((char *)&range->netaddr)[i] &= ((char *)&range->netmask)[i];
      }
      break;
   default:
      Error1("range option not supported with address family %d", pf);
      return STAT_NORETRY;
   }
   return 0;
}


/* set environment variables describing (part of) a socket address, e.g. 
   SOCAT_SOCKADDR. lr (local/remote) specifies a string like  "SOCK" or "PEER".
   proto should correspond to the third parameter of socket(2) and is used to 
   determine the presence of port information. */ 
int xiosetsockaddrenv(const char *lr,
		      union sockaddr_union *sau, socklen_t salen,
		      int proto) {
#  define XIOSOCKADDRENVLEN 256
   char namebuff[XIOSOCKADDRENVLEN];
   char valuebuff[XIOSOCKADDRENVLEN];
   int idx = 0, result;

   strcpy(namebuff, lr);
   switch (sau->soa.sa_family) {
#if WITH_UNIX
   case PF_UNIX:
      result =
	 xiosetsockaddrenv_unix(idx, strchr(namebuff, '\0'), XIOSOCKADDRENVLEN-strlen(lr),
				valuebuff, XIOSOCKADDRENVLEN,
				&sau->un, salen, proto);
      xiosetenv(namebuff, valuebuff, 1);
      break;
#endif /* WITH_UNIX */
#if WITH_IP4
   case PF_INET:
      do {
	 result =
	    xiosetsockaddrenv_ip4(idx, strchr(namebuff, '\0'), XIOSOCKADDRENVLEN-strlen(lr),
				  valuebuff, XIOSOCKADDRENVLEN,
				  &sau->ip4, proto);
	 xiosetenv(namebuff, valuebuff, 1);
	 namebuff[strlen(lr)] = '\0';  ++idx;
      } while (result > 0);
      break; 
#endif /* WITH_IP4 */
#if WITH_IP6
   case PF_INET6:
      strcpy(namebuff, lr);
      do {
	 result =
	    xiosetsockaddrenv_ip6(idx, strchr(namebuff, '\0'), XIOSOCKADDRENVLEN-strlen(lr),
				  valuebuff, XIOSOCKADDRENVLEN,
				  &sau->ip6, proto);
	 xiosetenv(namebuff, valuebuff, 1);
	 namebuff[strlen(lr)] = '\0';  ++idx;
      } while (result > 0);
      break; 
#endif /* WITH_IP6 */
#if LATER
   case PF_PACKET:
      result = xiosetsockaddrenv_packet(lr, (void *)sau, proto); break;
#endif
   default:
      result = -1;
      break;
   }
   return result;
#  undef XIOSOCKADDRENVLEN
}

#endif /* _WITH_SOCKET */

/* these do sockets internally */

/* retrieves options so-type and so-prototype from opts, calls socket, and
   ev. generates an appropriate error message.
   returns 0 on success or -1 if an error occurred. */
int 
xiosocket(struct opt *opts, int pf, int socktype, int proto, int msglevel) {
   int result;

   retropt_int(opts, OPT_SO_TYPE, &socktype);
   retropt_int(opts, OPT_SO_PROTOTYPE, &proto);
   result = Socket(pf, socktype, proto);
   if (result < 0) {
      Msg4(msglevel, "socket(%d, %d, %d): %s",
	     pf, socktype, proto, strerror(errno));
      return -1;
   }
   return result;
}

/* retrieves options so-type and so-prototype from opts, calls socketpair, and
   ev. generates an appropriate error message.
   returns 0 on success or -1 if an error occurred. */
int 
xiosocketpair(struct opt *opts, int pf, int socktype, int proto, int sv[2]) {
   int result;

   retropt_int(opts, OPT_SO_TYPE, &socktype);
   retropt_int(opts, OPT_SO_PROTOTYPE, &proto);
   result = xiosocketpair2(pf, socktype, proto, sv);
   return result;
}