Merge remote-tracking branch 'origin/released'

Conflicts:
	tools/plink/misc.h
	tools/plink/ssh.c
	tools/plink/sshbn.c
	tools/plink/winplink.c

1 files changed, 1835 insertions, 1747 deletions

diff --git a/tools/plink/winnet.c b/tools/plink/winnet.c
index 11f9ba52e..039701cf0 100644
--- a/tools/plink/winnet.c
+++ b/tools/plink/winnet.c
@@ -1,1747 +1,1835 @@
-/*

- * Windows networking abstraction.

- *

- * For the IPv6 code in here I am indebted to Jeroen Massar and

- * unfix.org.

- */

-

-#include <stdio.h>

-#include <stdlib.h>

-#include <assert.h>

-

-#define DEFINE_PLUG_METHOD_MACROS

-#include "putty.h"

-#include "network.h"

-#include "tree234.h"

-

-#include <ws2tcpip.h>

-

-#ifndef NO_IPV6

-const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;

-const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;

-#endif

-

-#define ipv4_is_loopback(addr) \

-	((p_ntohl(addr.s_addr) & 0xFF000000L) == 0x7F000000L)

-

-/*

- * We used to typedef struct Socket_tag *Socket.

- *

- * Since we have made the networking abstraction slightly more

- * abstract, Socket no longer means a tcp socket (it could mean

- * an ssl socket).  So now we must use Actual_Socket when we know

- * we are talking about a tcp socket.

- */

-typedef struct Socket_tag *Actual_Socket;

-

-/*

- * Mutable state that goes with a SockAddr: stores information

- * about where in the list of candidate IP(v*) addresses we've

- * currently got to.

- */

-typedef struct SockAddrStep_tag SockAddrStep;

-struct SockAddrStep_tag {

-#ifndef NO_IPV6

-    struct addrinfo *ai;	       /* steps along addr->ais */

-#endif

-    int curraddr;

-};

-

-struct Socket_tag {

-    const struct socket_function_table *fn;

-    /* the above variable absolutely *must* be the first in this structure */

-    char *error;

-    SOCKET s;

-    Plug plug;

-    void *private_ptr;

-    bufchain output_data;

-    int connected;

-    int writable;

-    int frozen; /* this causes readability notifications to be ignored */

-    int frozen_readable; /* this means we missed at least one readability

-			  * notification while we were frozen */

-    int localhost_only;		       /* for listening sockets */

-    char oobdata[1];

-    int sending_oob;

-    int oobinline, nodelay, keepalive, privport;

-    enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;

-    SockAddr addr;

-    SockAddrStep step;

-    int port;

-    int pending_error;		       /* in case send() returns error */

-    /*

-     * We sometimes need pairs of Socket structures to be linked:

-     * if we are listening on the same IPv6 and v4 port, for

-     * example. So here we define `parent' and `child' pointers to

-     * track this link.

-     */

-    Actual_Socket parent, child;

-};

-

-struct SockAddr_tag {

-    int refcount;

-    char *error;

-    int resolved;

-#ifndef NO_IPV6

-    struct addrinfo *ais;	       /* Addresses IPv6 style. */

-#endif

-    unsigned long *addresses;	       /* Addresses IPv4 style. */

-    int naddresses;

-    char hostname[512];		       /* Store an unresolved host name. */

-};

-

-/*

- * Which address family this address belongs to. AF_INET for IPv4;

- * AF_INET6 for IPv6; AF_UNSPEC indicates that name resolution has

- * not been done and a simple host name is held in this SockAddr

- * structure.

- */

-#ifndef NO_IPV6

-#define SOCKADDR_FAMILY(addr, step) \

-    (!(addr)->resolved ? AF_UNSPEC : \

-     (step).ai ? (step).ai->ai_family : AF_INET)

-#else

-#define SOCKADDR_FAMILY(addr, step) \

-    (!(addr)->resolved ? AF_UNSPEC : AF_INET)

-#endif

-

-/*

- * Start a SockAddrStep structure to step through multiple

- * addresses.

- */

-#ifndef NO_IPV6

-#define START_STEP(addr, step) \

-    ((step).ai = (addr)->ais, (step).curraddr = 0)

-#else

-#define START_STEP(addr, step) \

-    ((step).curraddr = 0)

-#endif

-

-static tree234 *sktree;

-

-static int cmpfortree(void *av, void *bv)

-{

-    Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv;

-    unsigned long as = (unsigned long) a->s, bs = (unsigned long) b->s;

-    if (as < bs)

-	return -1;

-    if (as > bs)

-	return +1;

-    if (a < b)

-	return -1;

-    if (a > b)

-	return +1;

-    return 0;

-}

-

-static int cmpforsearch(void *av, void *bv)

-{

-    Actual_Socket b = (Actual_Socket) bv;

-    unsigned long as = (unsigned long) av, bs = (unsigned long) b->s;

-    if (as < bs)

-	return -1;

-    if (as > bs)

-	return +1;

-    return 0;

-}

-

-DECL_WINDOWS_FUNCTION(static, int, WSAStartup, (WORD, LPWSADATA));

-DECL_WINDOWS_FUNCTION(static, int, WSACleanup, (void));

-DECL_WINDOWS_FUNCTION(static, int, closesocket, (SOCKET));

-DECL_WINDOWS_FUNCTION(static, u_long, ntohl, (u_long));

-DECL_WINDOWS_FUNCTION(static, u_long, htonl, (u_long));

-DECL_WINDOWS_FUNCTION(static, u_short, htons, (u_short));

-DECL_WINDOWS_FUNCTION(static, u_short, ntohs, (u_short));

-DECL_WINDOWS_FUNCTION(static, int, gethostname, (char *, int));

-DECL_WINDOWS_FUNCTION(static, struct hostent FAR *, gethostbyname,

-		      (const char FAR *));

-DECL_WINDOWS_FUNCTION(static, struct servent FAR *, getservbyname,

-		      (const char FAR *, const char FAR *));

-DECL_WINDOWS_FUNCTION(static, unsigned long, inet_addr, (const char FAR *));

-DECL_WINDOWS_FUNCTION(static, char FAR *, inet_ntoa, (struct in_addr));

-DECL_WINDOWS_FUNCTION(static, int, connect,

-		      (SOCKET, const struct sockaddr FAR *, int));

-DECL_WINDOWS_FUNCTION(static, int, bind,

-		      (SOCKET, const struct sockaddr FAR *, int));

-DECL_WINDOWS_FUNCTION(static, int, setsockopt,

-		      (SOCKET, int, int, const char FAR *, int));

-DECL_WINDOWS_FUNCTION(static, SOCKET, socket, (int, int, int));

-DECL_WINDOWS_FUNCTION(static, int, listen, (SOCKET, int));

-DECL_WINDOWS_FUNCTION(static, int, send, (SOCKET, const char FAR *, int, int));

-DECL_WINDOWS_FUNCTION(static, int, shutdown, (SOCKET, int));

-DECL_WINDOWS_FUNCTION(static, int, ioctlsocket,

-		      (SOCKET, long, u_long FAR *));

-DECL_WINDOWS_FUNCTION(static, SOCKET, accept,

-		      (SOCKET, struct sockaddr FAR *, int FAR *));

-DECL_WINDOWS_FUNCTION(static, int, recv, (SOCKET, char FAR *, int, int));

-DECL_WINDOWS_FUNCTION(static, int, WSAIoctl,

-		      (SOCKET, DWORD, LPVOID, DWORD, LPVOID, DWORD,

-		       LPDWORD, LPWSAOVERLAPPED,

-		       LPWSAOVERLAPPED_COMPLETION_ROUTINE));

-#ifndef NO_IPV6

-DECL_WINDOWS_FUNCTION(static, int, getaddrinfo,

-		      (const char *nodename, const char *servname,

-		       const struct addrinfo *hints, struct addrinfo **res));

-DECL_WINDOWS_FUNCTION(static, void, freeaddrinfo, (struct addrinfo *res));

-DECL_WINDOWS_FUNCTION(static, int, getnameinfo,

-		      (const struct sockaddr FAR * sa, socklen_t salen,

-		       char FAR * host, size_t hostlen, char FAR * serv,

-		       size_t servlen, int flags));

-DECL_WINDOWS_FUNCTION(static, char *, gai_strerror, (int ecode));

-DECL_WINDOWS_FUNCTION(static, int, WSAAddressToStringA,

-		      (LPSOCKADDR, DWORD, LPWSAPROTOCOL_INFO,

-		       LPSTR, LPDWORD));

-#endif

-

-static HMODULE winsock_module = NULL;

-static WSADATA wsadata;

-#ifndef NO_IPV6

-static HMODULE winsock2_module = NULL;

-static HMODULE wship6_module = NULL;

-#endif

-

-int sk_startup(int hi, int lo)

-{

-    WORD winsock_ver;

-

-    winsock_ver = MAKEWORD(hi, lo);

-

-    if (p_WSAStartup(winsock_ver, &wsadata)) {

-	return FALSE;

-    }

-

-    if (LOBYTE(wsadata.wVersion) != LOBYTE(winsock_ver)) {

-	return FALSE;

-    }

-

-#ifdef NET_SETUP_DIAGNOSTICS

-    {

-	char buf[80];

-	sprintf(buf, "Using WinSock %d.%d", hi, lo);

-	logevent(NULL, buf);

-    }

-#endif

-    return TRUE;

-}

-

-void sk_init(void)

-{

-#ifndef NO_IPV6

-    winsock2_module =

-#endif

-        winsock_module = load_system32_dll("ws2_32.dll");

-    if (!winsock_module) {

-	winsock_module = load_system32_dll("wsock32.dll");

-    }

-    if (!winsock_module)

-	fatalbox("Unable to load any WinSock library");

-

-#ifndef NO_IPV6

-    /* Check if we have getaddrinfo in Winsock */

-    if (GetProcAddress(winsock_module, "getaddrinfo") != NULL) {

-#ifdef NET_SETUP_DIAGNOSTICS

-	logevent(NULL, "Native WinSock IPv6 support detected");

-#endif

-	GET_WINDOWS_FUNCTION(winsock_module, getaddrinfo);

-	GET_WINDOWS_FUNCTION(winsock_module, freeaddrinfo);

-	GET_WINDOWS_FUNCTION(winsock_module, getnameinfo);

-	GET_WINDOWS_FUNCTION(winsock_module, gai_strerror);

-    } else {

-	/* Fall back to wship6.dll for Windows 2000 */

-	wship6_module = load_system32_dll("wship6.dll");

-	if (wship6_module) {

-#ifdef NET_SETUP_DIAGNOSTICS

-	    logevent(NULL, "WSH IPv6 support detected");

-#endif

-	    GET_WINDOWS_FUNCTION(wship6_module, getaddrinfo);

-	    GET_WINDOWS_FUNCTION(wship6_module, freeaddrinfo);

-	    GET_WINDOWS_FUNCTION(wship6_module, getnameinfo);

-	    GET_WINDOWS_FUNCTION(wship6_module, gai_strerror);

-	} else {

-#ifdef NET_SETUP_DIAGNOSTICS

-	    logevent(NULL, "No IPv6 support detected");

-#endif

-	}

-    }

-    GET_WINDOWS_FUNCTION(winsock2_module, WSAAddressToStringA);

-#else

-#ifdef NET_SETUP_DIAGNOSTICS

-    logevent(NULL, "PuTTY was built without IPv6 support");

-#endif

-#endif

-

-    GET_WINDOWS_FUNCTION(winsock_module, WSAAsyncSelect);

-    GET_WINDOWS_FUNCTION(winsock_module, WSAEventSelect);

-    GET_WINDOWS_FUNCTION(winsock_module, select);

-    GET_WINDOWS_FUNCTION(winsock_module, WSAGetLastError);

-    GET_WINDOWS_FUNCTION(winsock_module, WSAEnumNetworkEvents);

-    GET_WINDOWS_FUNCTION(winsock_module, WSAStartup);

-    GET_WINDOWS_FUNCTION(winsock_module, WSACleanup);

-    GET_WINDOWS_FUNCTION(winsock_module, closesocket);

-    GET_WINDOWS_FUNCTION(winsock_module, ntohl);

-    GET_WINDOWS_FUNCTION(winsock_module, htonl);

-    GET_WINDOWS_FUNCTION(winsock_module, htons);

-    GET_WINDOWS_FUNCTION(winsock_module, ntohs);

-    GET_WINDOWS_FUNCTION(winsock_module, gethostname);

-    GET_WINDOWS_FUNCTION(winsock_module, gethostbyname);

-    GET_WINDOWS_FUNCTION(winsock_module, getservbyname);

-    GET_WINDOWS_FUNCTION(winsock_module, inet_addr);

-    GET_WINDOWS_FUNCTION(winsock_module, inet_ntoa);

-    GET_WINDOWS_FUNCTION(winsock_module, connect);

-    GET_WINDOWS_FUNCTION(winsock_module, bind);

-    GET_WINDOWS_FUNCTION(winsock_module, setsockopt);

-    GET_WINDOWS_FUNCTION(winsock_module, socket);

-    GET_WINDOWS_FUNCTION(winsock_module, listen);

-    GET_WINDOWS_FUNCTION(winsock_module, send);

-    GET_WINDOWS_FUNCTION(winsock_module, shutdown);

-    GET_WINDOWS_FUNCTION(winsock_module, ioctlsocket);

-    GET_WINDOWS_FUNCTION(winsock_module, accept);

-    GET_WINDOWS_FUNCTION(winsock_module, recv);

-    GET_WINDOWS_FUNCTION(winsock_module, WSAIoctl);

-

-    /* Try to get the best WinSock version we can get */

-    if (!sk_startup(2,2) &&

-	!sk_startup(2,0) &&

-	!sk_startup(1,1)) {

-	fatalbox("Unable to initialise WinSock");

-    }

-

-    sktree = newtree234(cmpfortree);

-}

-

-void sk_cleanup(void)

-{

-    Actual_Socket s;

-    int i;

-

-    if (sktree) {

-	for (i = 0; (s = index234(sktree, i)) != NULL; i++) {

-	    p_closesocket(s->s);

-	}

-	freetree234(sktree);

-	sktree = NULL;

-    }

-

-    if (p_WSACleanup)

-	p_WSACleanup();

-    if (winsock_module)

-	FreeLibrary(winsock_module);

-#ifndef NO_IPV6

-    if (wship6_module)

-	FreeLibrary(wship6_module);

-#endif

-}

-

-char *winsock_error_string(int error)

-{

-    switch (error) {

-      case WSAEACCES:

-	return "Network error: Permission denied";

-      case WSAEADDRINUSE:

-	return "Network error: Address already in use";

-      case WSAEADDRNOTAVAIL:

-	return "Network error: Cannot assign requested address";

-      case WSAEAFNOSUPPORT:

-	return

-	    "Network error: Address family not supported by protocol family";

-      case WSAEALREADY:

-	return "Network error: Operation already in progress";

-      case WSAECONNABORTED:

-	return "Network error: Software caused connection abort";

-      case WSAECONNREFUSED:

-	return "Network error: Connection refused";

-      case WSAECONNRESET:

-	return "Network error: Connection reset by peer";

-      case WSAEDESTADDRREQ:

-	return "Network error: Destination address required";

-      case WSAEFAULT:

-	return "Network error: Bad address";

-      case WSAEHOSTDOWN:

-	return "Network error: Host is down";

-      case WSAEHOSTUNREACH:

-	return "Network error: No route to host";

-      case WSAEINPROGRESS:

-	return "Network error: Operation now in progress";

-      case WSAEINTR:

-	return "Network error: Interrupted function call";

-      case WSAEINVAL:

-	return "Network error: Invalid argument";

-      case WSAEISCONN:

-	return "Network error: Socket is already connected";

-      case WSAEMFILE:

-	return "Network error: Too many open files";

-      case WSAEMSGSIZE:

-	return "Network error: Message too long";

-      case WSAENETDOWN:

-	return "Network error: Network is down";

-      case WSAENETRESET:

-	return "Network error: Network dropped connection on reset";

-      case WSAENETUNREACH:

-	return "Network error: Network is unreachable";

-      case WSAENOBUFS:

-	return "Network error: No buffer space available";

-      case WSAENOPROTOOPT:

-	return "Network error: Bad protocol option";

-      case WSAENOTCONN:

-	return "Network error: Socket is not connected";

-      case WSAENOTSOCK:

-	return "Network error: Socket operation on non-socket";

-      case WSAEOPNOTSUPP:

-	return "Network error: Operation not supported";

-      case WSAEPFNOSUPPORT:

-	return "Network error: Protocol family not supported";

-      case WSAEPROCLIM:

-	return "Network error: Too many processes";

-      case WSAEPROTONOSUPPORT:

-	return "Network error: Protocol not supported";

-      case WSAEPROTOTYPE:

-	return "Network error: Protocol wrong type for socket";

-      case WSAESHUTDOWN:

-	return "Network error: Cannot send after socket shutdown";

-      case WSAESOCKTNOSUPPORT:

-	return "Network error: Socket type not supported";

-      case WSAETIMEDOUT:

-	return "Network error: Connection timed out";

-      case WSAEWOULDBLOCK:

-	return "Network error: Resource temporarily unavailable";

-      case WSAEDISCON:

-	return "Network error: Graceful shutdown in progress";

-      default:

-	return "Unknown network error";

-    }

-}

-

-SockAddr sk_namelookup(const char *host, char **canonicalname,

-		       int address_family)

-{

-    SockAddr ret = snew(struct SockAddr_tag);

-    unsigned long a;

-    char realhost[8192];

-    int hint_family;

-

-    /* Default to IPv4. */

-    hint_family = (address_family == ADDRTYPE_IPV4 ? AF_INET :

-#ifndef NO_IPV6

-		   address_family == ADDRTYPE_IPV6 ? AF_INET6 :

-#endif

-		   AF_UNSPEC);

-

-    /* Clear the structure and default to IPv4. */

-    memset(ret, 0, sizeof(struct SockAddr_tag));

-#ifndef NO_IPV6

-    ret->ais = NULL;

-#endif

-    ret->addresses = NULL;

-    ret->resolved = FALSE;

-    ret->refcount = 1;

-    *realhost = '\0';

-

-    if ((a = p_inet_addr(host)) == (unsigned long) INADDR_NONE) {

-	struct hostent *h = NULL;

-	int err;

-#ifndef NO_IPV6

-	/*

-	 * Use getaddrinfo when it's available

-	 */

-	if (p_getaddrinfo) {

-	    struct addrinfo hints;

-#ifdef NET_SETUP_DIAGNOSTICS

-	    logevent(NULL, "Using getaddrinfo() for resolving");

-#endif

-	    memset(&hints, 0, sizeof(hints));

-	    hints.ai_family = hint_family;

-	    hints.ai_flags = AI_CANONNAME;

-	    if ((err = p_getaddrinfo(host, NULL, &hints, &ret->ais)) == 0)

-		ret->resolved = TRUE;

-	} else

-#endif

-	{

-#ifdef NET_SETUP_DIAGNOSTICS

-	    logevent(NULL, "Using gethostbyname() for resolving");

-#endif

-	    /*

-	     * Otherwise use the IPv4-only gethostbyname...

-	     * (NOTE: we don't use gethostbyname as a fallback!)

-	     */

-	    if ( (h = p_gethostbyname(host)) )

-		ret->resolved = TRUE;

-	    else

-		err = p_WSAGetLastError();

-	}

-

-	if (!ret->resolved) {

-	    ret->error = (err == WSAENETDOWN ? "Network is down" :

-			  err == WSAHOST_NOT_FOUND ? "Host does not exist" :

-			  err == WSATRY_AGAIN ? "Host not found" :

-#ifndef NO_IPV6

-			  p_getaddrinfo&&p_gai_strerror ? p_gai_strerror(err) :

-#endif

-			  "gethostbyname: unknown error");

-	} else {

-	    ret->error = NULL;

-

-#ifndef NO_IPV6

-	    /* If we got an address info use that... */

-	    if (ret->ais) {

-		/* Are we in IPv4 fallback mode? */

-		/* We put the IPv4 address into the a variable so we can further-on use the IPv4 code... */

-		if (ret->ais->ai_family == AF_INET)

-		    memcpy(&a,

-			   (char *) &((SOCKADDR_IN *) ret->ais->

-				      ai_addr)->sin_addr, sizeof(a));

-

-		if (ret->ais->ai_canonname)

-		    strncpy(realhost, ret->ais->ai_canonname, lenof(realhost));

-		else

-		    strncpy(realhost, host, lenof(realhost));

-	    }

-	    /* We used the IPv4-only gethostbyname()... */

-	    else

-#endif

-	    {

-		int n;

-		for (n = 0; h->h_addr_list[n]; n++);

-		ret->addresses = snewn(n, unsigned long);

-		ret->naddresses = n;

-		for (n = 0; n < ret->naddresses; n++) {

-		    memcpy(&a, h->h_addr_list[n], sizeof(a));

-		    ret->addresses[n] = p_ntohl(a);

-		}

-		memcpy(&a, h->h_addr, sizeof(a));

-		/* This way we are always sure the h->h_name is valid :) */

-		strncpy(realhost, h->h_name, sizeof(realhost));

-	    }

-	}

-    } else {

-	/*

-	 * This must be a numeric IPv4 address because it caused a

-	 * success return from inet_addr.

-	 */

-	ret->addresses = snewn(1, unsigned long);

-	ret->naddresses = 1;

-	ret->addresses[0] = p_ntohl(a);

-	ret->resolved = TRUE;

-	strncpy(realhost, host, sizeof(realhost));

-    }

-    realhost[lenof(realhost)-1] = '\0';

-    *canonicalname = snewn(1+strlen(realhost), char);

-    strcpy(*canonicalname, realhost);

-    return ret;

-}

-

-SockAddr sk_nonamelookup(const char *host)

-{

-    SockAddr ret = snew(struct SockAddr_tag);

-    ret->error = NULL;

-    ret->resolved = FALSE;

-#ifndef NO_IPV6

-    ret->ais = NULL;

-#endif

-    ret->addresses = NULL;

-    ret->naddresses = 0;

-    ret->refcount = 1;

-    strncpy(ret->hostname, host, lenof(ret->hostname));

-    ret->hostname[lenof(ret->hostname)-1] = '\0';

-    return ret;

-}

-

-int sk_nextaddr(SockAddr addr, SockAddrStep *step)

-{

-#ifndef NO_IPV6

-    if (step->ai) {

-	if (step->ai->ai_next) {

-	    step->ai = step->ai->ai_next;

-	    return TRUE;

-	} else

-	    return FALSE;

-    }

-#endif

-    if (step->curraddr+1 < addr->naddresses) {

-	step->curraddr++;

-	return TRUE;

-    } else {

-	return FALSE;

-    }

-}

-

-void sk_getaddr(SockAddr addr, char *buf, int buflen)

-{

-    SockAddrStep step;

-    START_STEP(addr, step);

-

-#ifndef NO_IPV6

-    if (step.ai) {

-	int err = 0;

-	if (p_WSAAddressToStringA) {

-	    DWORD dwbuflen = buflen;

-	    err = p_WSAAddressToStringA(step.ai->ai_addr, step.ai->ai_addrlen,

-					NULL, buf, &dwbuflen);

-	} else

-	    err = -1;

-	if (err) {

-	    strncpy(buf, addr->hostname, buflen);

-	    if (!buf[0])

-		strncpy(buf, "<unknown>", buflen);

-	    buf[buflen-1] = '\0';

-	}

-    } else

-#endif

-    if (SOCKADDR_FAMILY(addr, step) == AF_INET) {

-	struct in_addr a;

-	assert(addr->addresses && step.curraddr < addr->naddresses);

-	a.s_addr = p_htonl(addr->addresses[step.curraddr]);

-	strncpy(buf, p_inet_ntoa(a), buflen);

-	buf[buflen-1] = '\0';

-    } else {

-	strncpy(buf, addr->hostname, buflen);

-	buf[buflen-1] = '\0';

-    }

-}

-

-int sk_hostname_is_local(char *name)

-{

-    return !strcmp(name, "localhost") ||

-	   !strcmp(name, "::1") ||

-	   !strncmp(name, "127.", 4);

-}

-

-static INTERFACE_INFO local_interfaces[16];

-static int n_local_interfaces;       /* 0=not yet, -1=failed, >0=number */

-

-static int ipv4_is_local_addr(struct in_addr addr)

-{

-    if (ipv4_is_loopback(addr))

-	return 1;		       /* loopback addresses are local */

-    if (!n_local_interfaces) {

-	SOCKET s = p_socket(AF_INET, SOCK_DGRAM, 0);

-	DWORD retbytes;

-

-	if (p_WSAIoctl &&

-	    p_WSAIoctl(s, SIO_GET_INTERFACE_LIST, NULL, 0,

-		       local_interfaces, sizeof(local_interfaces),

-		       &retbytes, NULL, NULL) == 0)

-	    n_local_interfaces = retbytes / sizeof(INTERFACE_INFO);

-	else

-	    logevent(NULL, "Unable to get list of local IP addresses");

-    }

-    if (n_local_interfaces > 0) {

-	int i;

-	for (i = 0; i < n_local_interfaces; i++) {

-	    SOCKADDR_IN *address =

-		(SOCKADDR_IN *)&local_interfaces[i].iiAddress;

-	    if (address->sin_addr.s_addr == addr.s_addr)

-		return 1;	       /* this address is local */

-	}

-    }

-    return 0;		       /* this address is not local */

-}

-

-int sk_address_is_local(SockAddr addr)

-{

-    SockAddrStep step;

-    int family;

-    START_STEP(addr, step);

-    family = SOCKADDR_FAMILY(addr, step);

-

-#ifndef NO_IPV6

-    if (family == AF_INET6) {

-    	return IN6_IS_ADDR_LOOPBACK((const struct in6_addr *)step.ai->ai_addr);

-    } else

-#endif

-    if (family == AF_INET) {

-#ifndef NO_IPV6

-	if (step.ai) {

-	    return ipv4_is_local_addr(((struct sockaddr_in *)step.ai->ai_addr)

-				      ->sin_addr);

-	} else

-#endif

-	{

-	    struct in_addr a;

-	    assert(addr->addresses && step.curraddr < addr->naddresses);

-	    a.s_addr = p_htonl(addr->addresses[step.curraddr]);

-	    return ipv4_is_local_addr(a);

-	}

-    } else {

-	assert(family == AF_UNSPEC);

-	return 0;		       /* we don't know; assume not */

-    }

-}

-

-int sk_addrtype(SockAddr addr)

-{

-    SockAddrStep step;

-    int family;

-    START_STEP(addr, step);

-    family = SOCKADDR_FAMILY(addr, step);

-

-    return (family == AF_INET ? ADDRTYPE_IPV4 :

-#ifndef NO_IPV6

-	    family == AF_INET6 ? ADDRTYPE_IPV6 :

-#endif

-	    ADDRTYPE_NAME);

-}

-

-void sk_addrcopy(SockAddr addr, char *buf)

-{

-    SockAddrStep step;

-    int family;

-    START_STEP(addr, step);

-    family = SOCKADDR_FAMILY(addr, step);

-

-    assert(family != AF_UNSPEC);

-#ifndef NO_IPV6

-    if (step.ai) {

-	if (family == AF_INET)

-	    memcpy(buf, &((struct sockaddr_in *)step.ai->ai_addr)->sin_addr,

-		   sizeof(struct in_addr));

-	else if (family == AF_INET6)

-	    memcpy(buf, &((struct sockaddr_in6 *)step.ai->ai_addr)->sin6_addr,

-		   sizeof(struct in6_addr));

-	else

-	    assert(FALSE);

-    } else

-#endif

-    if (family == AF_INET) {

-	struct in_addr a;

-	assert(addr->addresses && step.curraddr < addr->naddresses);

-	a.s_addr = p_htonl(addr->addresses[step.curraddr]);

-	memcpy(buf, (char*) &a.s_addr, 4);

-    }

-}

-

-void sk_addr_free(SockAddr addr)

-{

-    if (--addr->refcount > 0)

-	return;

-#ifndef NO_IPV6

-    if (addr->ais && p_freeaddrinfo)

-	p_freeaddrinfo(addr->ais);

-#endif

-    if (addr->addresses)

-	sfree(addr->addresses);

-    sfree(addr);

-}

-

-SockAddr sk_addr_dup(SockAddr addr)

-{

-    addr->refcount++;

-    return addr;

-}

-

-static Plug sk_tcp_plug(Socket sock, Plug p)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-    Plug ret = s->plug;

-    if (p)

-	s->plug = p;

-    return ret;

-}

-

-static void sk_tcp_flush(Socket s)

-{

-    /*

-     * We send data to the socket as soon as we can anyway,

-     * so we don't need to do anything here.  :-)

-     */

-}

-

-static void sk_tcp_close(Socket s);

-static int sk_tcp_write(Socket s, const char *data, int len);

-static int sk_tcp_write_oob(Socket s, const char *data, int len);

-static void sk_tcp_write_eof(Socket s);

-static void sk_tcp_set_private_ptr(Socket s, void *ptr);

-static void *sk_tcp_get_private_ptr(Socket s);

-static void sk_tcp_set_frozen(Socket s, int is_frozen);

-static const char *sk_tcp_socket_error(Socket s);

-

-extern char *do_select(SOCKET skt, int startup);

-

-Socket sk_register(void *sock, Plug plug)

-{

-    static const struct socket_function_table fn_table = {

-	sk_tcp_plug,

-	sk_tcp_close,

-	sk_tcp_write,

-	sk_tcp_write_oob,

-	sk_tcp_write_eof,

-	sk_tcp_flush,

-	sk_tcp_set_private_ptr,

-	sk_tcp_get_private_ptr,

-	sk_tcp_set_frozen,

-	sk_tcp_socket_error

-    };

-

-    DWORD err;

-    char *errstr;

-    Actual_Socket ret;

-

-    /*

-     * Create Socket structure.

-     */

-    ret = snew(struct Socket_tag);

-    ret->fn = &fn_table;

-    ret->error = NULL;

-    ret->plug = plug;

-    bufchain_init(&ret->output_data);

-    ret->writable = 1;		       /* to start with */

-    ret->sending_oob = 0;

-    ret->outgoingeof = EOF_NO;

-    ret->frozen = 1;

-    ret->frozen_readable = 0;

-    ret->localhost_only = 0;	       /* unused, but best init anyway */

-    ret->pending_error = 0;

-    ret->parent = ret->child = NULL;

-    ret->addr = NULL;

-

-    ret->s = (SOCKET)sock;

-

-    if (ret->s == INVALID_SOCKET) {

-	err = p_WSAGetLastError();

-	ret->error = winsock_error_string(err);

-	return (Socket) ret;

-    }

-

-    ret->oobinline = 0;

-

-    /* Set up a select mechanism. This could be an AsyncSelect on a

-     * window, or an EventSelect on an event object. */

-    errstr = do_select(ret->s, 1);

-    if (errstr) {

-	ret->error = errstr;

-	return (Socket) ret;

-    }

-

-    add234(sktree, ret);

-

-    return (Socket) ret;

-}

-

-static DWORD try_connect(Actual_Socket sock)

-{

-    SOCKET s;

-#ifndef NO_IPV6

-    SOCKADDR_IN6 a6;

-#endif

-    SOCKADDR_IN a;

-    DWORD err;

-    char *errstr;

-    short localport;

-    int family;

-

-    if (sock->s != INVALID_SOCKET) {

-	do_select(sock->s, 0);

-        p_closesocket(sock->s);

-    }

-

-    plug_log(sock->plug, 0, sock->addr, sock->port, NULL, 0);

-

-    /*

-     * Open socket.

-     */

-    family = SOCKADDR_FAMILY(sock->addr, sock->step);

-

-    /*

-     * Remove the socket from the tree before we overwrite its

-     * internal socket id, because that forms part of the tree's

-     * sorting criterion. We'll add it back before exiting this

-     * function, whether we changed anything or not.

-     */

-    del234(sktree, sock);

-

-    s = p_socket(family, SOCK_STREAM, 0);

-    sock->s = s;

-

-    if (s == INVALID_SOCKET) {

-	err = p_WSAGetLastError();

-	sock->error = winsock_error_string(err);

-	goto ret;

-    }

-

-    if (sock->oobinline) {

-	BOOL b = TRUE;

-	p_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b));

-    }

-

-    if (sock->nodelay) {

-	BOOL b = TRUE;

-	p_setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));

-    }

-

-    if (sock->keepalive) {

-	BOOL b = TRUE;

-	p_setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (void *) &b, sizeof(b));

-    }

-

-    /*

-     * Bind to local address.

-     */

-    if (sock->privport)

-	localport = 1023;	       /* count from 1023 downwards */

-    else

-	localport = 0;		       /* just use port 0 (ie winsock picks) */

-

-    /* Loop round trying to bind */

-    while (1) {

-	int sockcode;

-

-#ifndef NO_IPV6

-	if (family == AF_INET6) {

-	    memset(&a6, 0, sizeof(a6));

-	    a6.sin6_family = AF_INET6;

-          /*a6.sin6_addr = in6addr_any; */ /* == 0 done by memset() */

-	    a6.sin6_port = p_htons(localport);

-	} else

-#endif

-	{

-	    a.sin_family = AF_INET;

-	    a.sin_addr.s_addr = p_htonl(INADDR_ANY);

-	    a.sin_port = p_htons(localport);

-	}

-#ifndef NO_IPV6

-	sockcode = p_bind(s, (family == AF_INET6 ?

-			      (struct sockaddr *) &a6 :

-			      (struct sockaddr *) &a),

-			  (family == AF_INET6 ? sizeof(a6) : sizeof(a)));

-#else

-	sockcode = p_bind(s, (struct sockaddr *) &a, sizeof(a));

-#endif

-	if (sockcode != SOCKET_ERROR) {

-	    err = 0;

-	    break;		       /* done */

-	} else {

-	    err = p_WSAGetLastError();

-	    if (err != WSAEADDRINUSE)  /* failed, for a bad reason */

-		break;

-	}

-

-	if (localport == 0)

-	    break;		       /* we're only looping once */

-	localport--;

-	if (localport == 0)

-	    break;		       /* we might have got to the end */

-    }

-

-    if (err) {

-	sock->error = winsock_error_string(err);

-	goto ret;

-    }

-

-    /*

-     * Connect to remote address.

-     */

-#ifndef NO_IPV6

-    if (sock->step.ai) {

-	if (family == AF_INET6) {

-	    a6.sin6_family = AF_INET6;

-	    a6.sin6_port = p_htons((short) sock->port);

-	    a6.sin6_addr =

-		((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_addr;

-	    a6.sin6_flowinfo = ((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_flowinfo;

-	    a6.sin6_scope_id = ((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_scope_id;

-	} else {

-	    a.sin_family = AF_INET;

-	    a.sin_addr =

-		((struct sockaddr_in *) sock->step.ai->ai_addr)->sin_addr;

-	    a.sin_port = p_htons((short) sock->port);

-	}

-    } else

-#endif

-    {

-	assert(sock->addr->addresses && sock->step.curraddr < sock->addr->naddresses);

-	a.sin_family = AF_INET;

-	a.sin_addr.s_addr = p_htonl(sock->addr->addresses[sock->step.curraddr]);

-	a.sin_port = p_htons((short) sock->port);

-    }

-

-    /* Set up a select mechanism. This could be an AsyncSelect on a

-     * window, or an EventSelect on an event object. */

-    errstr = do_select(s, 1);

-    if (errstr) {

-	sock->error = errstr;

-	err = 1;

-	goto ret;

-    }

-

-    if ((

-#ifndef NO_IPV6

-	    p_connect(s,

-		      ((family == AF_INET6) ? (struct sockaddr *) &a6 :

-		       (struct sockaddr *) &a),

-		      (family == AF_INET6) ? sizeof(a6) : sizeof(a))

-#else

-	    p_connect(s, (struct sockaddr *) &a, sizeof(a))

-#endif

-	) == SOCKET_ERROR) {

-	err = p_WSAGetLastError();

-	/*

-	 * We expect a potential EWOULDBLOCK here, because the

-	 * chances are the front end has done a select for

-	 * FD_CONNECT, so that connect() will complete

-	 * asynchronously.

-	 */

-	if ( err != WSAEWOULDBLOCK ) {

-	    sock->error = winsock_error_string(err);

-	    goto ret;

-	}

-    } else {

-	/*

-	 * If we _don't_ get EWOULDBLOCK, the connect has completed

-	 * and we should set the socket as writable.

-	 */

-	sock->writable = 1;

-    }

-

-    err = 0;

-

-    ret:

-

-    /*

-     * No matter what happened, put the socket back in the tree.

-     */

-    add234(sktree, sock);

-

-    if (err)

-	plug_log(sock->plug, 1, sock->addr, sock->port, sock->error, err);

-    return err;

-}

-

-Socket sk_new(SockAddr addr, int port, int privport, int oobinline,

-	      int nodelay, int keepalive, Plug plug)

-{

-    static const struct socket_function_table fn_table = {

-	sk_tcp_plug,

-	sk_tcp_close,

-	sk_tcp_write,

-	sk_tcp_write_oob,

-	sk_tcp_write_eof,

-	sk_tcp_flush,

-	sk_tcp_set_private_ptr,

-	sk_tcp_get_private_ptr,

-	sk_tcp_set_frozen,

-	sk_tcp_socket_error

-    };

-

-    Actual_Socket ret;

-    DWORD err;

-

-    /*

-     * Create Socket structure.

-     */

-    ret = snew(struct Socket_tag);

-    ret->fn = &fn_table;

-    ret->error = NULL;

-    ret->plug = plug;

-    bufchain_init(&ret->output_data);

-    ret->connected = 0;		       /* to start with */

-    ret->writable = 0;		       /* to start with */

-    ret->sending_oob = 0;

-    ret->outgoingeof = EOF_NO;

-    ret->frozen = 0;

-    ret->frozen_readable = 0;

-    ret->localhost_only = 0;	       /* unused, but best init anyway */

-    ret->pending_error = 0;

-    ret->parent = ret->child = NULL;

-    ret->oobinline = oobinline;

-    ret->nodelay = nodelay;

-    ret->keepalive = keepalive;

-    ret->privport = privport;

-    ret->port = port;

-    ret->addr = addr;

-    START_STEP(ret->addr, ret->step);

-    ret->s = INVALID_SOCKET;

-

-    err = 0;

-    do {

-        err = try_connect(ret);

-    } while (err && sk_nextaddr(ret->addr, &ret->step));

-

-    return (Socket) ret;

-}

-

-Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only,

-		      int orig_address_family)

-{

-    static const struct socket_function_table fn_table = {

-	sk_tcp_plug,

-	sk_tcp_close,

-	sk_tcp_write,

-	sk_tcp_write_oob,

-	sk_tcp_write_eof,

-	sk_tcp_flush,

-	sk_tcp_set_private_ptr,

-	sk_tcp_get_private_ptr,

-	sk_tcp_set_frozen,

-	sk_tcp_socket_error

-    };

-

-    SOCKET s;

-#ifndef NO_IPV6

-    SOCKADDR_IN6 a6;

-#endif

-    SOCKADDR_IN a;

-

-    DWORD err;

-    char *errstr;

-    Actual_Socket ret;

-    int retcode;

-    int on = 1;

-

-    int address_family;

-

-    /*

-     * Create Socket structure.

-     */

-    ret = snew(struct Socket_tag);

-    ret->fn = &fn_table;

-    ret->error = NULL;

-    ret->plug = plug;

-    bufchain_init(&ret->output_data);

-    ret->writable = 0;		       /* to start with */

-    ret->sending_oob = 0;

-    ret->outgoingeof = EOF_NO;

-    ret->frozen = 0;

-    ret->frozen_readable = 0;

-    ret->localhost_only = local_host_only;

-    ret->pending_error = 0;

-    ret->parent = ret->child = NULL;

-    ret->addr = NULL;

-

-    /*

-     * Translate address_family from platform-independent constants

-     * into local reality.

-     */

-    address_family = (orig_address_family == ADDRTYPE_IPV4 ? AF_INET :

-#ifndef NO_IPV6

-		      orig_address_family == ADDRTYPE_IPV6 ? AF_INET6 :

-#endif

-		      AF_UNSPEC);

-

-    /*

-     * Our default, if passed the `don't care' value

-     * ADDRTYPE_UNSPEC, is to listen on IPv4. If IPv6 is supported,

-     * we will also set up a second socket listening on IPv6, but

-     * the v4 one is primary since that ought to work even on

-     * non-v6-supporting systems.

-     */

-    if (address_family == AF_UNSPEC) address_family = AF_INET;

-

-    /*

-     * Open socket.

-     */

-    s = p_socket(address_family, SOCK_STREAM, 0);

-    ret->s = s;

-

-    if (s == INVALID_SOCKET) {

-	err = p_WSAGetLastError();

-	ret->error = winsock_error_string(err);

-	return (Socket) ret;

-    }

-

-    ret->oobinline = 0;

-

-    p_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));

-

-#ifndef NO_IPV6

-	if (address_family == AF_INET6) {

-	    memset(&a6, 0, sizeof(a6));

-	    a6.sin6_family = AF_INET6;

-	    /* FIXME: srcaddr is ignored for IPv6, because I (SGT) don't

-	     * know how to do it. :-)

-	     * (jeroen:) saddr is specified as an address.. eg 2001:db8::1

-	     * Thus we need either a parser that understands [2001:db8::1]:80

-	     * style addresses and/or enhance this to understand hostnames too. */

-	    if (local_host_only)

-		a6.sin6_addr = in6addr_loopback;

-	    else

-		a6.sin6_addr = in6addr_any;

-	    a6.sin6_port = p_htons(port);

-	} else

-#endif

-	{

-	    int got_addr = 0;

-	    a.sin_family = AF_INET;

-

-	    /*

-	     * Bind to source address. First try an explicitly

-	     * specified one...

-	     */

-	    if (srcaddr) {

-		a.sin_addr.s_addr = p_inet_addr(srcaddr);

-		if (a.sin_addr.s_addr != INADDR_NONE) {

-		    /* Override localhost_only with specified listen addr. */

-		    ret->localhost_only = ipv4_is_loopback(a.sin_addr);

-		    got_addr = 1;

-		}

-	    }

-

-	    /*

-	     * ... and failing that, go with one of the standard ones.

-	     */

-	    if (!got_addr) {

-		if (local_host_only)

-		    a.sin_addr.s_addr = p_htonl(INADDR_LOOPBACK);

-		else

-		    a.sin_addr.s_addr = p_htonl(INADDR_ANY);

-	    }

-

-	    a.sin_port = p_htons((short)port);

-	}

-#ifndef NO_IPV6

-	retcode = p_bind(s, (address_family == AF_INET6 ?

-			   (struct sockaddr *) &a6 :

-			   (struct sockaddr *) &a),

-		       (address_family ==

-			AF_INET6 ? sizeof(a6) : sizeof(a)));

-#else

-	retcode = p_bind(s, (struct sockaddr *) &a, sizeof(a));

-#endif

-	if (retcode != SOCKET_ERROR) {

-	    err = 0;

-	} else {

-	    err = p_WSAGetLastError();

-	}

-

-    if (err) {

-	p_closesocket(s);

-	ret->error = winsock_error_string(err);

-	return (Socket) ret;

-    }

-

-

-    if (p_listen(s, SOMAXCONN) == SOCKET_ERROR) {

-        p_closesocket(s);

-	ret->error = winsock_error_string(err);

-	return (Socket) ret;

-    }

-

-    /* Set up a select mechanism. This could be an AsyncSelect on a

-     * window, or an EventSelect on an event object. */

-    errstr = do_select(s, 1);

-    if (errstr) {

-	p_closesocket(s);

-	ret->error = errstr;

-	return (Socket) ret;

-    }

-

-    add234(sktree, ret);

-

-#ifndef NO_IPV6

-    /*

-     * If we were given ADDRTYPE_UNSPEC, we must also create an

-     * IPv6 listening socket and link it to this one.

-     */

-    if (address_family == AF_INET && orig_address_family == ADDRTYPE_UNSPEC) {

-	Actual_Socket other;

-

-	other = (Actual_Socket) sk_newlistener(srcaddr, port, plug,

-					       local_host_only, ADDRTYPE_IPV6);

-

-	if (other) {

-	    if (!other->error) {

-		other->parent = ret;

-		ret->child = other;

-	    } else {

-		sfree(other);

-	    }

-	}

-    }

-#endif

-

-    return (Socket) ret;

-}

-

-static void sk_tcp_close(Socket sock)

-{

-    extern char *do_select(SOCKET skt, int startup);

-    Actual_Socket s = (Actual_Socket) sock;

-

-    if (s->child)

-	sk_tcp_close((Socket)s->child);

-

-    del234(sktree, s);

-    do_select(s->s, 0);

-    p_closesocket(s->s);

-    if (s->addr)

-	sk_addr_free(s->addr);

-    sfree(s);

-}

-

-/*

- * The function which tries to send on a socket once it's deemed

- * writable.

- */

-void try_send(Actual_Socket s)

-{

-    while (s->sending_oob || bufchain_size(&s->output_data) > 0) {

-	int nsent;

-	DWORD err;

-	void *data;

-	int len, urgentflag;

-

-	if (s->sending_oob) {

-	    urgentflag = MSG_OOB;

-	    len = s->sending_oob;

-	    data = &s->oobdata;

-	} else {

-	    urgentflag = 0;

-	    bufchain_prefix(&s->output_data, &data, &len);

-	}

-	nsent = p_send(s->s, data, len, urgentflag);

-	noise_ultralight(nsent);

-	if (nsent <= 0) {

-	    err = (nsent < 0 ? p_WSAGetLastError() : 0);

-	    if ((err < WSABASEERR && nsent < 0) || err == WSAEWOULDBLOCK) {

-		/*

-		 * Perfectly normal: we've sent all we can for the moment.

-		 * 

-		 * (Some WinSock send() implementations can return

-		 * <0 but leave no sensible error indication -

-		 * WSAGetLastError() is called but returns zero or

-		 * a small number - so we check that case and treat

-		 * it just like WSAEWOULDBLOCK.)

-		 */

-		s->writable = FALSE;

-		return;

-	    } else if (nsent == 0 ||

-		       err == WSAECONNABORTED || err == WSAECONNRESET) {

-		/*

-		 * If send() returns CONNABORTED or CONNRESET, we

-		 * unfortunately can't just call plug_closing(),

-		 * because it's quite likely that we're currently

-		 * _in_ a call from the code we'd be calling back

-		 * to, so we'd have to make half the SSH code

-		 * reentrant. Instead we flag a pending error on

-		 * the socket, to be dealt with (by calling

-		 * plug_closing()) at some suitable future moment.

-		 */

-		s->pending_error = err;

-		return;

-	    } else {

-		/* We're inside the Windows frontend here, so we know

-		 * that the frontend handle is unnecessary. */

-		logevent(NULL, winsock_error_string(err));

-		fatalbox("%s", winsock_error_string(err));

-	    }

-	} else {

-	    if (s->sending_oob) {

-		if (nsent < len) {

-		    memmove(s->oobdata, s->oobdata+nsent, len-nsent);

-		    s->sending_oob = len - nsent;

-		} else {

-		    s->sending_oob = 0;

-		}

-	    } else {

-		bufchain_consume(&s->output_data, nsent);

-	    }

-	}

-    }

-

-    /*

-     * If we reach here, we've finished sending everything we might

-     * have needed to send. Send EOF, if we need to.

-     */

-    if (s->outgoingeof == EOF_PENDING) {

-        p_shutdown(s->s, SD_SEND);

-        s->outgoingeof = EOF_SENT;

-    }

-}

-

-static int sk_tcp_write(Socket sock, const char *buf, int len)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-

-    assert(s->outgoingeof == EOF_NO);

-

-    /*

-     * Add the data to the buffer list on the socket.

-     */

-    bufchain_add(&s->output_data, buf, len);

-

-    /*

-     * Now try sending from the start of the buffer list.

-     */

-    if (s->writable)

-	try_send(s);

-

-    return bufchain_size(&s->output_data);

-}

-

-static int sk_tcp_write_oob(Socket sock, const char *buf, int len)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-

-    assert(s->outgoingeof == EOF_NO);

-

-    /*

-     * Replace the buffer list on the socket with the data.

-     */

-    bufchain_clear(&s->output_data);

-    assert(len <= sizeof(s->oobdata));

-    memcpy(s->oobdata, buf, len);

-    s->sending_oob = len;

-

-    /*

-     * Now try sending from the start of the buffer list.

-     */

-    if (s->writable)

-	try_send(s);

-

-    return s->sending_oob;

-}

-

-static void sk_tcp_write_eof(Socket sock)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-

-    assert(s->outgoingeof == EOF_NO);

-

-    /*

-     * Mark the socket as pending outgoing EOF.

-     */

-    s->outgoingeof = EOF_PENDING;

-

-    /*

-     * Now try sending from the start of the buffer list.

-     */

-    if (s->writable)

-	try_send(s);

-}

-

-int select_result(WPARAM wParam, LPARAM lParam)

-{

-    int ret, open;

-    DWORD err;

-    char buf[20480];		       /* nice big buffer for plenty of speed */

-    Actual_Socket s;

-    u_long atmark;

-

-    /* wParam is the socket itself */

-

-    if (wParam == 0)

-	return 1;		       /* boggle */

-

-    s = find234(sktree, (void *) wParam, cmpforsearch);

-    if (!s)

-	return 1;		       /* boggle */

-

-    if ((err = WSAGETSELECTERROR(lParam)) != 0) {

-	/*

-	 * An error has occurred on this socket. Pass it to the

-	 * plug.

-	 */

-	if (s->addr) {

-	    plug_log(s->plug, 1, s->addr, s->port,

-		     winsock_error_string(err), err);

-	    while (s->addr && sk_nextaddr(s->addr, &s->step)) {

-		err = try_connect(s);

-	    }

-	}

-	if (err != 0)

-	    return plug_closing(s->plug, winsock_error_string(err), err, 0);

-	else

-	    return 1;

-    }

-

-    noise_ultralight(lParam);

-

-    switch (WSAGETSELECTEVENT(lParam)) {

-      case FD_CONNECT:

-	s->connected = s->writable = 1;

-	/*

-	 * Once a socket is connected, we can stop falling

-	 * back through the candidate addresses to connect

-	 * to.

-	 */

-	if (s->addr) {

-	    sk_addr_free(s->addr);

-	    s->addr = NULL;

-	}

-	break;

-      case FD_READ:

-	/* In the case the socket is still frozen, we don't even bother */

-	if (s->frozen) {

-	    s->frozen_readable = 1;

-	    break;

-	}

-

-	/*

-	 * We have received data on the socket. For an oobinline

-	 * socket, this might be data _before_ an urgent pointer,

-	 * in which case we send it to the back end with type==1

-	 * (data prior to urgent).

-	 */

-	if (s->oobinline) {

-	    atmark = 1;

-	    p_ioctlsocket(s->s, SIOCATMARK, &atmark);

-	    /*

-	     * Avoid checking the return value from ioctlsocket(),

-	     * on the grounds that some WinSock wrappers don't

-	     * support it. If it does nothing, we get atmark==1,

-	     * which is equivalent to `no OOB pending', so the

-	     * effect will be to non-OOB-ify any OOB data.

-	     */

-	} else

-	    atmark = 1;

-

-	ret = p_recv(s->s, buf, sizeof(buf), 0);

-	noise_ultralight(ret);

-	if (ret < 0) {

-	    err = p_WSAGetLastError();

-	    if (err == WSAEWOULDBLOCK) {

-		break;

-	    }

-	}

-	if (ret < 0) {

-	    return plug_closing(s->plug, winsock_error_string(err), err,

-				0);

-	} else if (0 == ret) {

-	    return plug_closing(s->plug, NULL, 0, 0);

-	} else {

-	    return plug_receive(s->plug, atmark ? 0 : 1, buf, ret);

-	}

-	break;

-      case FD_OOB:

-	/*

-	 * This will only happen on a non-oobinline socket. It

-	 * indicates that we can immediately perform an OOB read

-	 * and get back OOB data, which we will send to the back

-	 * end with type==2 (urgent data).

-	 */

-	ret = p_recv(s->s, buf, sizeof(buf), MSG_OOB);

-	noise_ultralight(ret);

-	if (ret <= 0) {

-	    char *str = (ret == 0 ? "Internal networking trouble" :

-			 winsock_error_string(p_WSAGetLastError()));

-	    /* We're inside the Windows frontend here, so we know

-	     * that the frontend handle is unnecessary. */

-	    logevent(NULL, str);

-	    fatalbox("%s", str);

-	} else {

-	    return plug_receive(s->plug, 2, buf, ret);

-	}

-	break;

-      case FD_WRITE:

-	{

-	    int bufsize_before, bufsize_after;

-	    s->writable = 1;

-	    bufsize_before = s->sending_oob + bufchain_size(&s->output_data);

-	    try_send(s);

-	    bufsize_after = s->sending_oob + bufchain_size(&s->output_data);

-	    if (bufsize_after < bufsize_before)

-		plug_sent(s->plug, bufsize_after);

-	}

-	break;

-      case FD_CLOSE:

-	/* Signal a close on the socket. First read any outstanding data. */

-	open = 1;

-	do {

-	    ret = p_recv(s->s, buf, sizeof(buf), 0);

-	    if (ret < 0) {

-		err = p_WSAGetLastError();

-		if (err == WSAEWOULDBLOCK)

-		    break;

-		return plug_closing(s->plug, winsock_error_string(err),

-				    err, 0);

-	    } else {

-		if (ret)

-		    open &= plug_receive(s->plug, 0, buf, ret);

-		else

-		    open &= plug_closing(s->plug, NULL, 0, 0);

-	    }

-	} while (ret > 0);

-	return open;

-       case FD_ACCEPT:

-	{

-#ifdef NO_IPV6

-	    struct sockaddr_in isa;

-#else

-            struct sockaddr_storage isa;

-#endif

-	    int addrlen = sizeof(isa);

-	    SOCKET t;  /* socket of connection */

-

-	    memset(&isa, 0, sizeof(isa));

-	    err = 0;

-	    t = p_accept(s->s,(struct sockaddr *)&isa,&addrlen);

-	    if (t == INVALID_SOCKET)

-	    {

-		err = p_WSAGetLastError();

-		if (err == WSATRY_AGAIN)

-		    break;

-	    }

-#ifndef NO_IPV6

-            if (isa.ss_family == AF_INET &&

-                s->localhost_only &&

-                !ipv4_is_local_addr(((struct sockaddr_in *)&isa)->sin_addr))

-#else

-	    if (s->localhost_only && !ipv4_is_local_addr(isa.sin_addr))

-#endif

-	    {

-		p_closesocket(t);      /* dodgy WinSock let nonlocal through */

-	    } else if (plug_accepting(s->plug, (void*)t)) {

-		p_closesocket(t);      /* denied or error */

-	    }

-	}

-    }

-

-    return 1;

-}

-

-/*

- * Deal with socket errors detected in try_send().

- */

-void net_pending_errors(void)

-{

-    int i;

-    Actual_Socket s;

-

-    /*

-     * This might be a fiddly business, because it's just possible

-     * that handling a pending error on one socket might cause

-     * others to be closed. (I can't think of any reason this might

-     * happen in current SSH implementation, but to maintain

-     * generality of this network layer I'll assume the worst.)

-     * 

-     * So what we'll do is search the socket list for _one_ socket

-     * with a pending error, and then handle it, and then search

-     * the list again _from the beginning_. Repeat until we make a

-     * pass with no socket errors present. That way we are

-     * protected against the socket list changing under our feet.

-     */

-

-    do {

-	for (i = 0; (s = index234(sktree, i)) != NULL; i++) {

-	    if (s->pending_error) {

-		/*

-		 * An error has occurred on this socket. Pass it to the

-		 * plug.

-		 */

-		plug_closing(s->plug,

-			     winsock_error_string(s->pending_error),

-			     s->pending_error, 0);

-		break;

-	    }

-	}

-    } while (s);

-}

-

-/*

- * Each socket abstraction contains a `void *' private field in

- * which the client can keep state.

- */

-static void sk_tcp_set_private_ptr(Socket sock, void *ptr)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-    s->private_ptr = ptr;

-}

-

-static void *sk_tcp_get_private_ptr(Socket sock)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-    return s->private_ptr;

-}

-

-/*

- * Special error values are returned from sk_namelookup and sk_new

- * if there's a problem. These functions extract an error message,

- * or return NULL if there's no problem.

- */

-const char *sk_addr_error(SockAddr addr)

-{

-    return addr->error;

-}

-static const char *sk_tcp_socket_error(Socket sock)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-    return s->error;

-}

-

-static void sk_tcp_set_frozen(Socket sock, int is_frozen)

-{

-    Actual_Socket s = (Actual_Socket) sock;

-    if (s->frozen == is_frozen)

-	return;

-    s->frozen = is_frozen;

-    if (!is_frozen) {

-	do_select(s->s, 1);

-	if (s->frozen_readable) {

-	    char c;

-	    p_recv(s->s, &c, 1, MSG_PEEK);

-	}

-    }

-    s->frozen_readable = 0;

-}

-

-void socket_reselect_all(void)

-{

-    Actual_Socket s;

-    int i;

-

-    for (i = 0; (s = index234(sktree, i)) != NULL; i++) {

-	if (!s->frozen)

-	    do_select(s->s, 1);

-    }

-}

-

-/*

- * For Plink: enumerate all sockets currently active.

- */

-SOCKET first_socket(int *state)

-{

-    Actual_Socket s;

-    *state = 0;

-    s = index234(sktree, (*state)++);

-    return s ? s->s : INVALID_SOCKET;

-}

-

-SOCKET next_socket(int *state)

-{

-    Actual_Socket s = index234(sktree, (*state)++);

-    return s ? s->s : INVALID_SOCKET;

-}

-

-extern int socket_writable(SOCKET skt)

-{

-    Actual_Socket s = find234(sktree, (void *)skt, cmpforsearch);

-

-    if (s)

-	return bufchain_size(&s->output_data) > 0;

-    else

-	return 0;

-}

-

-int net_service_lookup(char *service)

-{

-    struct servent *se;

-    se = p_getservbyname(service, NULL);

-    if (se != NULL)

-	return p_ntohs(se->s_port);

-    else

-	return 0;

-}

-

-char *get_hostname(void)

-{

-    int len = 128;

-    char *hostname = NULL;

-    do {

-	len *= 2;

-	hostname = sresize(hostname, len, char);

-	if (p_gethostname(hostname, len) < 0) {

-	    sfree(hostname);

-	    hostname = NULL;

-	    break;

-	}

-    } while (strlen(hostname) >= (size_t)(len-1));

-    return hostname;

-}

-

-SockAddr platform_get_x11_unix_address(const char *display, int displaynum,

-				       char **canonicalname)

-{

-    SockAddr ret = snew(struct SockAddr_tag);

-    memset(ret, 0, sizeof(struct SockAddr_tag));

-    ret->error = "unix sockets not supported on this platform";

-    ret->refcount = 1;

-    return ret;

-}

+/*
+ * Windows networking abstraction.
+ *
+ * For the IPv6 code in here I am indebted to Jeroen Massar and
+ * unfix.org.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#define DEFINE_PLUG_METHOD_MACROS
+#include "putty.h"
+#include "network.h"
+#include "tree234.h"
+
+#include <ws2tcpip.h>
+
+#ifndef NO_IPV6
+const struct in6_addr in6addr_any = IN6ADDR_ANY_INIT;
+const struct in6_addr in6addr_loopback = IN6ADDR_LOOPBACK_INIT;
+#endif
+
+#define ipv4_is_loopback(addr) \
+	((p_ntohl(addr.s_addr) & 0xFF000000L) == 0x7F000000L)
+
+/*
+ * We used to typedef struct Socket_tag *Socket.
+ *
+ * Since we have made the networking abstraction slightly more
+ * abstract, Socket no longer means a tcp socket (it could mean
+ * an ssl socket).  So now we must use Actual_Socket when we know
+ * we are talking about a tcp socket.
+ */
+typedef struct Socket_tag *Actual_Socket;
+
+/*
+ * Mutable state that goes with a SockAddr: stores information
+ * about where in the list of candidate IP(v*) addresses we've
+ * currently got to.
+ */
+typedef struct SockAddrStep_tag SockAddrStep;
+struct SockAddrStep_tag {
+#ifndef NO_IPV6
+    struct addrinfo *ai;	       /* steps along addr->ais */
+#endif
+    int curraddr;
+};
+
+struct Socket_tag {
+    const struct socket_function_table *fn;
+    /* the above variable absolutely *must* be the first in this structure */
+    char *error;
+    SOCKET s;
+    Plug plug;
+    bufchain output_data;
+    int connected;
+    int writable;
+    int frozen; /* this causes readability notifications to be ignored */
+    int frozen_readable; /* this means we missed at least one readability
+			  * notification while we were frozen */
+    int localhost_only;		       /* for listening sockets */
+    char oobdata[1];
+    int sending_oob;
+    int oobinline, nodelay, keepalive, privport;
+    enum { EOF_NO, EOF_PENDING, EOF_SENT } outgoingeof;
+    SockAddr addr;
+    SockAddrStep step;
+    int port;
+    int pending_error;		       /* in case send() returns error */
+    /*
+     * We sometimes need pairs of Socket structures to be linked:
+     * if we are listening on the same IPv6 and v4 port, for
+     * example. So here we define `parent' and `child' pointers to
+     * track this link.
+     */
+    Actual_Socket parent, child;
+};
+
+struct SockAddr_tag {
+    int refcount;
+    char *error;
+    int resolved;
+    int namedpipe; /* indicates that this SockAddr is phony, holding a Windows
+                    * named pipe pathname instead of a network address */
+#ifndef NO_IPV6
+    struct addrinfo *ais;	       /* Addresses IPv6 style. */
+#endif
+    unsigned long *addresses;	       /* Addresses IPv4 style. */
+    int naddresses;
+    char hostname[512];		       /* Store an unresolved host name. */
+};
+
+/*
+ * Which address family this address belongs to. AF_INET for IPv4;
+ * AF_INET6 for IPv6; AF_UNSPEC indicates that name resolution has
+ * not been done and a simple host name is held in this SockAddr
+ * structure.
+ */
+#ifndef NO_IPV6
+#define SOCKADDR_FAMILY(addr, step) \
+    (!(addr)->resolved ? AF_UNSPEC : \
+     (step).ai ? (step).ai->ai_family : AF_INET)
+#else
+#define SOCKADDR_FAMILY(addr, step) \
+    (!(addr)->resolved ? AF_UNSPEC : AF_INET)
+#endif
+
+/*
+ * Start a SockAddrStep structure to step through multiple
+ * addresses.
+ */
+#ifndef NO_IPV6
+#define START_STEP(addr, step) \
+    ((step).ai = (addr)->ais, (step).curraddr = 0)
+#else
+#define START_STEP(addr, step) \
+    ((step).curraddr = 0)
+#endif
+
+static tree234 *sktree;
+
+static int cmpfortree(void *av, void *bv)
+{
+    Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv;
+    unsigned long as = (unsigned long) a->s, bs = (unsigned long) b->s;
+    if (as < bs)
+	return -1;
+    if (as > bs)
+	return +1;
+    if (a < b)
+	return -1;
+    if (a > b)
+	return +1;
+    return 0;
+}
+
+static int cmpforsearch(void *av, void *bv)
+{
+    Actual_Socket b = (Actual_Socket) bv;
+    unsigned long as = (unsigned long) av, bs = (unsigned long) b->s;
+    if (as < bs)
+	return -1;
+    if (as > bs)
+	return +1;
+    return 0;
+}
+
+DECL_WINDOWS_FUNCTION(static, int, WSAStartup, (WORD, LPWSADATA));
+DECL_WINDOWS_FUNCTION(static, int, WSACleanup, (void));
+DECL_WINDOWS_FUNCTION(static, int, closesocket, (SOCKET));
+DECL_WINDOWS_FUNCTION(static, u_long, ntohl, (u_long));
+DECL_WINDOWS_FUNCTION(static, u_long, htonl, (u_long));
+DECL_WINDOWS_FUNCTION(static, u_short, htons, (u_short));
+DECL_WINDOWS_FUNCTION(static, u_short, ntohs, (u_short));
+DECL_WINDOWS_FUNCTION(static, int, gethostname, (char *, int));
+DECL_WINDOWS_FUNCTION(static, struct hostent FAR *, gethostbyname,
+		      (const char FAR *));
+DECL_WINDOWS_FUNCTION(static, struct servent FAR *, getservbyname,
+		      (const char FAR *, const char FAR *));
+DECL_WINDOWS_FUNCTION(static, unsigned long, inet_addr, (const char FAR *));
+DECL_WINDOWS_FUNCTION(static, char FAR *, inet_ntoa, (struct in_addr));
+DECL_WINDOWS_FUNCTION(static, int, connect,
+		      (SOCKET, const struct sockaddr FAR *, int));
+DECL_WINDOWS_FUNCTION(static, int, bind,
+		      (SOCKET, const struct sockaddr FAR *, int));
+DECL_WINDOWS_FUNCTION(static, int, setsockopt,
+		      (SOCKET, int, int, const char FAR *, int));
+DECL_WINDOWS_FUNCTION(static, SOCKET, socket, (int, int, int));
+DECL_WINDOWS_FUNCTION(static, int, listen, (SOCKET, int));
+DECL_WINDOWS_FUNCTION(static, int, send, (SOCKET, const char FAR *, int, int));
+DECL_WINDOWS_FUNCTION(static, int, shutdown, (SOCKET, int));
+DECL_WINDOWS_FUNCTION(static, int, ioctlsocket,
+		      (SOCKET, long, u_long FAR *));
+DECL_WINDOWS_FUNCTION(static, SOCKET, accept,
+		      (SOCKET, struct sockaddr FAR *, int FAR *));
+DECL_WINDOWS_FUNCTION(static, int, recv, (SOCKET, char FAR *, int, int));
+DECL_WINDOWS_FUNCTION(static, int, WSAIoctl,
+		      (SOCKET, DWORD, LPVOID, DWORD, LPVOID, DWORD,
+		       LPDWORD, LPWSAOVERLAPPED,
+		       LPWSAOVERLAPPED_COMPLETION_ROUTINE));
+#ifndef NO_IPV6
+DECL_WINDOWS_FUNCTION(static, int, getaddrinfo,
+		      (const char *nodename, const char *servname,
+		       const struct addrinfo *hints, struct addrinfo **res));
+DECL_WINDOWS_FUNCTION(static, void, freeaddrinfo, (struct addrinfo *res));
+DECL_WINDOWS_FUNCTION(static, int, getnameinfo,
+		      (const struct sockaddr FAR * sa, socklen_t salen,
+		       char FAR * host, size_t hostlen, char FAR * serv,
+		       size_t servlen, int flags));
+DECL_WINDOWS_FUNCTION(static, char *, gai_strerror, (int ecode));
+DECL_WINDOWS_FUNCTION(static, int, WSAAddressToStringA,
+		      (LPSOCKADDR, DWORD, LPWSAPROTOCOL_INFO,
+		       LPSTR, LPDWORD));
+#endif
+
+static HMODULE winsock_module = NULL;
+static WSADATA wsadata;
+#ifndef NO_IPV6
+static HMODULE winsock2_module = NULL;
+static HMODULE wship6_module = NULL;
+#endif
+
+int sk_startup(int hi, int lo)
+{
+    WORD winsock_ver;
+
+    winsock_ver = MAKEWORD(hi, lo);
+
+    if (p_WSAStartup(winsock_ver, &wsadata)) {
+	return FALSE;
+    }
+
+    if (LOBYTE(wsadata.wVersion) != LOBYTE(winsock_ver)) {
+	return FALSE;
+    }
+
+#ifdef NET_SETUP_DIAGNOSTICS
+    {
+	char buf[80];
+	sprintf(buf, "Using WinSock %d.%d", hi, lo);
+	logevent(NULL, buf);
+    }
+#endif
+    return TRUE;
+}
+
+void sk_init(void)
+{
+#ifndef NO_IPV6
+    winsock2_module =
+#endif
+        winsock_module = load_system32_dll("ws2_32.dll");
+    if (!winsock_module) {
+	winsock_module = load_system32_dll("wsock32.dll");
+    }
+    if (!winsock_module)
+	fatalbox("Unable to load any WinSock library");
+
+#ifndef NO_IPV6
+    /* Check if we have getaddrinfo in Winsock */
+    if (GetProcAddress(winsock_module, "getaddrinfo") != NULL) {
+#ifdef NET_SETUP_DIAGNOSTICS
+	logevent(NULL, "Native WinSock IPv6 support detected");
+#endif
+	GET_WINDOWS_FUNCTION(winsock_module, getaddrinfo);
+	GET_WINDOWS_FUNCTION(winsock_module, freeaddrinfo);
+	GET_WINDOWS_FUNCTION(winsock_module, getnameinfo);
+	GET_WINDOWS_FUNCTION(winsock_module, gai_strerror);
+    } else {
+	/* Fall back to wship6.dll for Windows 2000 */
+	wship6_module = load_system32_dll("wship6.dll");
+	if (wship6_module) {
+#ifdef NET_SETUP_DIAGNOSTICS
+	    logevent(NULL, "WSH IPv6 support detected");
+#endif
+	    GET_WINDOWS_FUNCTION(wship6_module, getaddrinfo);
+	    GET_WINDOWS_FUNCTION(wship6_module, freeaddrinfo);
+	    GET_WINDOWS_FUNCTION(wship6_module, getnameinfo);
+	    GET_WINDOWS_FUNCTION(wship6_module, gai_strerror);
+	} else {
+#ifdef NET_SETUP_DIAGNOSTICS
+	    logevent(NULL, "No IPv6 support detected");
+#endif
+	}
+    }
+    GET_WINDOWS_FUNCTION(winsock2_module, WSAAddressToStringA);
+#else
+#ifdef NET_SETUP_DIAGNOSTICS
+    logevent(NULL, "PuTTY was built without IPv6 support");
+#endif
+#endif
+
+    GET_WINDOWS_FUNCTION(winsock_module, WSAAsyncSelect);
+    GET_WINDOWS_FUNCTION(winsock_module, WSAEventSelect);
+    GET_WINDOWS_FUNCTION(winsock_module, select);
+    GET_WINDOWS_FUNCTION(winsock_module, WSAGetLastError);
+    GET_WINDOWS_FUNCTION(winsock_module, WSAEnumNetworkEvents);
+    GET_WINDOWS_FUNCTION(winsock_module, WSAStartup);
+    GET_WINDOWS_FUNCTION(winsock_module, WSACleanup);
+    GET_WINDOWS_FUNCTION(winsock_module, closesocket);
+    GET_WINDOWS_FUNCTION(winsock_module, ntohl);
+    GET_WINDOWS_FUNCTION(winsock_module, htonl);
+    GET_WINDOWS_FUNCTION(winsock_module, htons);
+    GET_WINDOWS_FUNCTION(winsock_module, ntohs);
+    GET_WINDOWS_FUNCTION(winsock_module, gethostname);
+    GET_WINDOWS_FUNCTION(winsock_module, gethostbyname);
+    GET_WINDOWS_FUNCTION(winsock_module, getservbyname);
+    GET_WINDOWS_FUNCTION(winsock_module, inet_addr);
+    GET_WINDOWS_FUNCTION(winsock_module, inet_ntoa);
+    GET_WINDOWS_FUNCTION(winsock_module, connect);
+    GET_WINDOWS_FUNCTION(winsock_module, bind);
+    GET_WINDOWS_FUNCTION(winsock_module, setsockopt);
+    GET_WINDOWS_FUNCTION(winsock_module, socket);
+    GET_WINDOWS_FUNCTION(winsock_module, listen);
+    GET_WINDOWS_FUNCTION(winsock_module, send);
+    GET_WINDOWS_FUNCTION(winsock_module, shutdown);
+    GET_WINDOWS_FUNCTION(winsock_module, ioctlsocket);
+    GET_WINDOWS_FUNCTION(winsock_module, accept);
+    GET_WINDOWS_FUNCTION(winsock_module, recv);
+    GET_WINDOWS_FUNCTION(winsock_module, WSAIoctl);
+
+    /* Try to get the best WinSock version we can get */
+    if (!sk_startup(2,2) &&
+	!sk_startup(2,0) &&
+	!sk_startup(1,1)) {
+	fatalbox("Unable to initialise WinSock");
+    }
+
+    sktree = newtree234(cmpfortree);
+}
+
+void sk_cleanup(void)
+{
+    Actual_Socket s;
+    int i;
+
+    if (sktree) {
+	for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
+	    p_closesocket(s->s);
+	}
+	freetree234(sktree);
+	sktree = NULL;
+    }
+
+    if (p_WSACleanup)
+	p_WSACleanup();
+    if (winsock_module)
+	FreeLibrary(winsock_module);
+#ifndef NO_IPV6
+    if (wship6_module)
+	FreeLibrary(wship6_module);
+#endif
+}
+
+struct errstring {
+    int error;
+    char *text;
+};
+
+static int errstring_find(void *av, void *bv)
+{
+    int *a = (int *)av;
+    struct errstring *b = (struct errstring *)bv;
+    if (*a < b->error)
+        return -1;
+    if (*a > b->error)
+        return +1;
+    return 0;
+}
+static int errstring_compare(void *av, void *bv)
+{
+    struct errstring *a = (struct errstring *)av;
+    return errstring_find(&a->error, bv);
+}
+
+static tree234 *errstrings = NULL;
+
+char *winsock_error_string(int error)
+{
+    const char prefix[] = "Network error: ";
+    struct errstring *es;
+
+    /*
+     * Error codes we know about and have historically had reasonably
+     * sensible error messages for.
+     */
+    switch (error) {
+      case WSAEACCES:
+	return "Network error: Permission denied";
+      case WSAEADDRINUSE:
+	return "Network error: Address already in use";
+      case WSAEADDRNOTAVAIL:
+	return "Network error: Cannot assign requested address";
+      case WSAEAFNOSUPPORT:
+	return
+	    "Network error: Address family not supported by protocol family";
+      case WSAEALREADY:
+	return "Network error: Operation already in progress";
+      case WSAECONNABORTED:
+	return "Network error: Software caused connection abort";
+      case WSAECONNREFUSED:
+	return "Network error: Connection refused";
+      case WSAECONNRESET:
+	return "Network error: Connection reset by peer";
+      case WSAEDESTADDRREQ:
+	return "Network error: Destination address required";
+      case WSAEFAULT:
+	return "Network error: Bad address";
+      case WSAEHOSTDOWN:
+	return "Network error: Host is down";
+      case WSAEHOSTUNREACH:
+	return "Network error: No route to host";
+      case WSAEINPROGRESS:
+	return "Network error: Operation now in progress";
+      case WSAEINTR:
+	return "Network error: Interrupted function call";
+      case WSAEINVAL:
+	return "Network error: Invalid argument";
+      case WSAEISCONN:
+	return "Network error: Socket is already connected";
+      case WSAEMFILE:
+	return "Network error: Too many open files";
+      case WSAEMSGSIZE:
+	return "Network error: Message too long";
+      case WSAENETDOWN:
+	return "Network error: Network is down";
+      case WSAENETRESET:
+	return "Network error: Network dropped connection on reset";
+      case WSAENETUNREACH:
+	return "Network error: Network is unreachable";
+      case WSAENOBUFS:
+	return "Network error: No buffer space available";
+      case WSAENOPROTOOPT:
+	return "Network error: Bad protocol option";
+      case WSAENOTCONN:
+	return "Network error: Socket is not connected";
+      case WSAENOTSOCK:
+	return "Network error: Socket operation on non-socket";
+      case WSAEOPNOTSUPP:
+	return "Network error: Operation not supported";
+      case WSAEPFNOSUPPORT:
+	return "Network error: Protocol family not supported";
+      case WSAEPROCLIM:
+	return "Network error: Too many processes";
+      case WSAEPROTONOSUPPORT:
+	return "Network error: Protocol not supported";
+      case WSAEPROTOTYPE:
+	return "Network error: Protocol wrong type for socket";
+      case WSAESHUTDOWN:
+	return "Network error: Cannot send after socket shutdown";
+      case WSAESOCKTNOSUPPORT:
+	return "Network error: Socket type not supported";
+      case WSAETIMEDOUT:
+	return "Network error: Connection timed out";
+      case WSAEWOULDBLOCK:
+	return "Network error: Resource temporarily unavailable";
+      case WSAEDISCON:
+	return "Network error: Graceful shutdown in progress";
+    }
+
+    /*
+     * Generic code to handle any other error.
+     *
+     * Slightly nasty hack here: we want to return a static string
+     * which the caller will never have to worry about freeing, but on
+     * the other hand if we call FormatMessage to get it then it will
+     * want to either allocate a buffer or write into one we own.
+     *
+     * So what we do is to maintain a tree234 of error strings we've
+     * already used. New ones are allocated from the heap, but then
+     * put in this tree and kept forever.
+     */
+
+    if (!errstrings)
+        errstrings = newtree234(errstring_compare);
+
+    es = find234(errstrings, &error, errstring_find);
+
+    if (!es) {
+        int bufsize, bufused;
+
+        es = snew(struct errstring);
+        es->error = error;
+        /* maximum size for FormatMessage is 64K */
+        bufsize = 65535 + sizeof(prefix);
+        es->text = snewn(bufsize, char);
+        strcpy(es->text, prefix);
+        bufused = strlen(es->text);
+        if (!FormatMessage((FORMAT_MESSAGE_FROM_SYSTEM |
+                            FORMAT_MESSAGE_IGNORE_INSERTS), NULL, error,
+                           MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                           es->text + bufused, bufsize - bufused, NULL)) {
+            sprintf(es->text + bufused,
+                    "Windows error code %d (and FormatMessage returned %d)", 
+                    error, GetLastError());
+        } else {
+            int len = strlen(es->text);
+            if (len > 0 && es->text[len-1] == '\n')
+                es->text[len-1] = '\0';
+        }
+        es->text = sresize(es->text, strlen(es->text) + 1, char);
+        add234(errstrings, es);
+    }
+
+    return es->text;
+}
+
+SockAddr sk_namelookup(const char *host, char **canonicalname,
+		       int address_family)
+{
+    SockAddr ret = snew(struct SockAddr_tag);
+    unsigned long a;
+    char realhost[8192];
+    int hint_family;
+
+    /* Default to IPv4. */
+    hint_family = (address_family == ADDRTYPE_IPV4 ? AF_INET :
+#ifndef NO_IPV6
+		   address_family == ADDRTYPE_IPV6 ? AF_INET6 :
+#endif
+		   AF_UNSPEC);
+
+    /* Clear the structure and default to IPv4. */
+    memset(ret, 0, sizeof(struct SockAddr_tag));
+#ifndef NO_IPV6
+    ret->ais = NULL;
+#endif
+    ret->namedpipe = FALSE;
+    ret->addresses = NULL;
+    ret->resolved = FALSE;
+    ret->refcount = 1;
+    *realhost = '\0';
+
+    if ((a = p_inet_addr(host)) == (unsigned long) INADDR_NONE) {
+	struct hostent *h = NULL;
+	int err;
+#ifndef NO_IPV6
+	/*
+	 * Use getaddrinfo when it's available
+	 */
+	if (p_getaddrinfo) {
+	    struct addrinfo hints;
+#ifdef NET_SETUP_DIAGNOSTICS
+	    logevent(NULL, "Using getaddrinfo() for resolving");
+#endif
+	    memset(&hints, 0, sizeof(hints));
+	    hints.ai_family = hint_family;
+	    hints.ai_flags = AI_CANONNAME;
+            {
+                /* strip [] on IPv6 address literals */
+                char *trimmed_host = host_strduptrim(host);
+                err = p_getaddrinfo(trimmed_host, NULL, &hints, &ret->ais);
+                sfree(trimmed_host);
+            }
+	    if (err == 0)
+		ret->resolved = TRUE;
+	} else
+#endif
+	{
+#ifdef NET_SETUP_DIAGNOSTICS
+	    logevent(NULL, "Using gethostbyname() for resolving");
+#endif
+	    /*
+	     * Otherwise use the IPv4-only gethostbyname...
+	     * (NOTE: we don't use gethostbyname as a fallback!)
+	     */
+	    if ( (h = p_gethostbyname(host)) )
+		ret->resolved = TRUE;
+	    else
+		err = p_WSAGetLastError();
+	}
+
+	if (!ret->resolved) {
+	    ret->error = (err == WSAENETDOWN ? "Network is down" :
+			  err == WSAHOST_NOT_FOUND ? "Host does not exist" :
+			  err == WSATRY_AGAIN ? "Host not found" :
+#ifndef NO_IPV6
+			  p_getaddrinfo&&p_gai_strerror ? p_gai_strerror(err) :
+#endif
+			  "gethostbyname: unknown error");
+	} else {
+	    ret->error = NULL;
+
+#ifndef NO_IPV6
+	    /* If we got an address info use that... */
+	    if (ret->ais) {
+		/* Are we in IPv4 fallback mode? */
+		/* We put the IPv4 address into the a variable so we can further-on use the IPv4 code... */
+		if (ret->ais->ai_family == AF_INET)
+		    memcpy(&a,
+			   (char *) &((SOCKADDR_IN *) ret->ais->
+				      ai_addr)->sin_addr, sizeof(a));
+
+		if (ret->ais->ai_canonname)
+		    strncpy(realhost, ret->ais->ai_canonname, lenof(realhost));
+		else
+		    strncpy(realhost, host, lenof(realhost));
+	    }
+	    /* We used the IPv4-only gethostbyname()... */
+	    else
+#endif
+	    {
+		int n;
+		for (n = 0; h->h_addr_list[n]; n++);
+		ret->addresses = snewn(n, unsigned long);
+		ret->naddresses = n;
+		for (n = 0; n < ret->naddresses; n++) {
+		    memcpy(&a, h->h_addr_list[n], sizeof(a));
+		    ret->addresses[n] = p_ntohl(a);
+		}
+		memcpy(&a, h->h_addr, sizeof(a));
+		/* This way we are always sure the h->h_name is valid :) */
+		strncpy(realhost, h->h_name, sizeof(realhost));
+	    }
+	}
+    } else {
+	/*
+	 * This must be a numeric IPv4 address because it caused a
+	 * success return from inet_addr.
+	 */
+	ret->addresses = snewn(1, unsigned long);
+	ret->naddresses = 1;
+	ret->addresses[0] = p_ntohl(a);
+	ret->resolved = TRUE;
+	strncpy(realhost, host, sizeof(realhost));
+    }
+    realhost[lenof(realhost)-1] = '\0';
+    *canonicalname = snewn(1+strlen(realhost), char);
+    strcpy(*canonicalname, realhost);
+    return ret;
+}
+
+SockAddr sk_nonamelookup(const char *host)
+{
+    SockAddr ret = snew(struct SockAddr_tag);
+    ret->error = NULL;
+    ret->resolved = FALSE;
+#ifndef NO_IPV6
+    ret->ais = NULL;
+#endif
+    ret->namedpipe = FALSE;
+    ret->addresses = NULL;
+    ret->naddresses = 0;
+    ret->refcount = 1;
+    strncpy(ret->hostname, host, lenof(ret->hostname));
+    ret->hostname[lenof(ret->hostname)-1] = '\0';
+    return ret;
+}
+
+SockAddr sk_namedpipe_addr(const char *pipename)
+{
+    SockAddr ret = snew(struct SockAddr_tag);
+    ret->error = NULL;
+    ret->resolved = FALSE;
+#ifndef NO_IPV6
+    ret->ais = NULL;
+#endif
+    ret->namedpipe = TRUE;
+    ret->addresses = NULL;
+    ret->naddresses = 0;
+    ret->refcount = 1;
+    strncpy(ret->hostname, pipename, lenof(ret->hostname));
+    ret->hostname[lenof(ret->hostname)-1] = '\0';
+    return ret;
+}
+
+int sk_nextaddr(SockAddr addr, SockAddrStep *step)
+{
+#ifndef NO_IPV6
+    if (step->ai) {
+	if (step->ai->ai_next) {
+	    step->ai = step->ai->ai_next;
+	    return TRUE;
+	} else
+	    return FALSE;
+    }
+#endif
+    if (step->curraddr+1 < addr->naddresses) {
+	step->curraddr++;
+	return TRUE;
+    } else {
+	return FALSE;
+    }
+}
+
+void sk_getaddr(SockAddr addr, char *buf, int buflen)
+{
+    SockAddrStep step;
+    START_STEP(addr, step);
+
+#ifndef NO_IPV6
+    if (step.ai) {
+	int err = 0;
+	if (p_WSAAddressToStringA) {
+	    DWORD dwbuflen = buflen;
+	    err = p_WSAAddressToStringA(step.ai->ai_addr, step.ai->ai_addrlen,
+					NULL, buf, &dwbuflen);
+	} else
+	    err = -1;
+	if (err) {
+	    strncpy(buf, addr->hostname, buflen);
+	    if (!buf[0])
+		strncpy(buf, "<unknown>", buflen);
+	    buf[buflen-1] = '\0';
+	}
+    } else
+#endif
+    if (SOCKADDR_FAMILY(addr, step) == AF_INET) {
+	struct in_addr a;
+	assert(addr->addresses && step.curraddr < addr->naddresses);
+	a.s_addr = p_htonl(addr->addresses[step.curraddr]);
+	strncpy(buf, p_inet_ntoa(a), buflen);
+	buf[buflen-1] = '\0';
+    } else {
+	strncpy(buf, addr->hostname, buflen);
+	buf[buflen-1] = '\0';
+    }
+}
+
+int sk_addr_needs_port(SockAddr addr)
+{
+    return addr->namedpipe ? FALSE : TRUE;
+}
+
+int sk_hostname_is_local(const char *name)
+{
+    return !strcmp(name, "localhost") ||
+	   !strcmp(name, "::1") ||
+	   !strncmp(name, "127.", 4);
+}
+
+static INTERFACE_INFO local_interfaces[16];
+static int n_local_interfaces;       /* 0=not yet, -1=failed, >0=number */
+
+static int ipv4_is_local_addr(struct in_addr addr)
+{
+    if (ipv4_is_loopback(addr))
+	return 1;		       /* loopback addresses are local */
+    if (!n_local_interfaces) {
+	SOCKET s = p_socket(AF_INET, SOCK_DGRAM, 0);
+	DWORD retbytes;
+
+	if (p_WSAIoctl &&
+	    p_WSAIoctl(s, SIO_GET_INTERFACE_LIST, NULL, 0,
+		       local_interfaces, sizeof(local_interfaces),
+		       &retbytes, NULL, NULL) == 0)
+	    n_local_interfaces = retbytes / sizeof(INTERFACE_INFO);
+	else
+	    logevent(NULL, "Unable to get list of local IP addresses");
+    }
+    if (n_local_interfaces > 0) {
+	int i;
+	for (i = 0; i < n_local_interfaces; i++) {
+	    SOCKADDR_IN *address =
+		(SOCKADDR_IN *)&local_interfaces[i].iiAddress;
+	    if (address->sin_addr.s_addr == addr.s_addr)
+		return 1;	       /* this address is local */
+	}
+    }
+    return 0;		       /* this address is not local */
+}
+
+int sk_address_is_local(SockAddr addr)
+{
+    SockAddrStep step;
+    int family;
+    START_STEP(addr, step);
+    family = SOCKADDR_FAMILY(addr, step);
+
+#ifndef NO_IPV6
+    if (family == AF_INET6) {
+    	return IN6_IS_ADDR_LOOPBACK(&((const struct sockaddr_in6 *)step.ai->ai_addr)->sin6_addr);
+    } else
+#endif
+    if (family == AF_INET) {
+#ifndef NO_IPV6
+	if (step.ai) {
+	    return ipv4_is_local_addr(((struct sockaddr_in *)step.ai->ai_addr)
+				      ->sin_addr);
+	} else
+#endif
+	{
+	    struct in_addr a;
+	    assert(addr->addresses && step.curraddr < addr->naddresses);
+	    a.s_addr = p_htonl(addr->addresses[step.curraddr]);
+	    return ipv4_is_local_addr(a);
+	}
+    } else {
+	assert(family == AF_UNSPEC);
+	return 0;		       /* we don't know; assume not */
+    }
+}
+
+int sk_address_is_special_local(SockAddr addr)
+{
+    return 0;                /* no Unix-domain socket analogue here */
+}
+
+int sk_addrtype(SockAddr addr)
+{
+    SockAddrStep step;
+    int family;
+    START_STEP(addr, step);
+    family = SOCKADDR_FAMILY(addr, step);
+
+    return (family == AF_INET ? ADDRTYPE_IPV4 :
+#ifndef NO_IPV6
+	    family == AF_INET6 ? ADDRTYPE_IPV6 :
+#endif
+	    ADDRTYPE_NAME);
+}
+
+void sk_addrcopy(SockAddr addr, char *buf)
+{
+    SockAddrStep step;
+    int family;
+    START_STEP(addr, step);
+    family = SOCKADDR_FAMILY(addr, step);
+
+    assert(family != AF_UNSPEC);
+#ifndef NO_IPV6
+    if (step.ai) {
+	if (family == AF_INET)
+	    memcpy(buf, &((struct sockaddr_in *)step.ai->ai_addr)->sin_addr,
+		   sizeof(struct in_addr));
+	else if (family == AF_INET6)
+	    memcpy(buf, &((struct sockaddr_in6 *)step.ai->ai_addr)->sin6_addr,
+		   sizeof(struct in6_addr));
+	else
+	    assert(FALSE);
+    } else
+#endif
+    if (family == AF_INET) {
+	struct in_addr a;
+	assert(addr->addresses && step.curraddr < addr->naddresses);
+	a.s_addr = p_htonl(addr->addresses[step.curraddr]);
+	memcpy(buf, (char*) &a.s_addr, 4);
+    }
+}
+
+void sk_addr_free(SockAddr addr)
+{
+    if (--addr->refcount > 0)
+	return;
+#ifndef NO_IPV6
+    if (addr->ais && p_freeaddrinfo)
+	p_freeaddrinfo(addr->ais);
+#endif
+    if (addr->addresses)
+	sfree(addr->addresses);
+    sfree(addr);
+}
+
+SockAddr sk_addr_dup(SockAddr addr)
+{
+    addr->refcount++;
+    return addr;
+}
+
+static Plug sk_tcp_plug(Socket sock, Plug p)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+    Plug ret = s->plug;
+    if (p)
+	s->plug = p;
+    return ret;
+}
+
+static void sk_tcp_flush(Socket s)
+{
+    /*
+     * We send data to the socket as soon as we can anyway,
+     * so we don't need to do anything here.  :-)
+     */
+}
+
+static void sk_tcp_close(Socket s);
+static int sk_tcp_write(Socket s, const char *data, int len);
+static int sk_tcp_write_oob(Socket s, const char *data, int len);
+static void sk_tcp_write_eof(Socket s);
+static void sk_tcp_set_frozen(Socket s, int is_frozen);
+static const char *sk_tcp_socket_error(Socket s);
+
+extern char *do_select(SOCKET skt, int startup);
+
+static Socket sk_tcp_accept(accept_ctx_t ctx, Plug plug)
+{
+    static const struct socket_function_table fn_table = {
+	sk_tcp_plug,
+	sk_tcp_close,
+	sk_tcp_write,
+	sk_tcp_write_oob,
+	sk_tcp_write_eof,
+	sk_tcp_flush,
+	sk_tcp_set_frozen,
+	sk_tcp_socket_error
+    };
+
+    DWORD err;
+    char *errstr;
+    Actual_Socket ret;
+
+    /*
+     * Create Socket structure.
+     */
+    ret = snew(struct Socket_tag);
+    ret->fn = &fn_table;
+    ret->error = NULL;
+    ret->plug = plug;
+    bufchain_init(&ret->output_data);
+    ret->writable = 1;		       /* to start with */
+    ret->sending_oob = 0;
+    ret->outgoingeof = EOF_NO;
+    ret->frozen = 1;
+    ret->frozen_readable = 0;
+    ret->localhost_only = 0;	       /* unused, but best init anyway */
+    ret->pending_error = 0;
+    ret->parent = ret->child = NULL;
+    ret->addr = NULL;
+
+    ret->s = (SOCKET)ctx.p;
+
+    if (ret->s == INVALID_SOCKET) {
+	err = p_WSAGetLastError();
+	ret->error = winsock_error_string(err);
+	return (Socket) ret;
+    }
+
+    ret->oobinline = 0;
+
+    /* Set up a select mechanism. This could be an AsyncSelect on a
+     * window, or an EventSelect on an event object. */
+    errstr = do_select(ret->s, 1);
+    if (errstr) {
+	ret->error = errstr;
+	return (Socket) ret;
+    }
+
+    add234(sktree, ret);
+
+    return (Socket) ret;
+}
+
+static DWORD try_connect(Actual_Socket sock)
+{
+    SOCKET s;
+#ifndef NO_IPV6
+    SOCKADDR_IN6 a6;
+#endif
+    SOCKADDR_IN a;
+    DWORD err;
+    char *errstr;
+    short localport;
+    int family;
+
+    if (sock->s != INVALID_SOCKET) {
+	do_select(sock->s, 0);
+        p_closesocket(sock->s);
+    }
+
+    plug_log(sock->plug, 0, sock->addr, sock->port, NULL, 0);
+
+    /*
+     * Open socket.
+     */
+    family = SOCKADDR_FAMILY(sock->addr, sock->step);
+
+    /*
+     * Remove the socket from the tree before we overwrite its
+     * internal socket id, because that forms part of the tree's
+     * sorting criterion. We'll add it back before exiting this
+     * function, whether we changed anything or not.
+     */
+    del234(sktree, sock);
+
+    s = p_socket(family, SOCK_STREAM, 0);
+    sock->s = s;
+
+    if (s == INVALID_SOCKET) {
+	err = p_WSAGetLastError();
+	sock->error = winsock_error_string(err);
+	goto ret;
+    }
+
+    if (sock->oobinline) {
+	BOOL b = TRUE;
+	p_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b));
+    }
+
+    if (sock->nodelay) {
+	BOOL b = TRUE;
+	p_setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (void *) &b, sizeof(b));
+    }
+
+    if (sock->keepalive) {
+	BOOL b = TRUE;
+	p_setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (void *) &b, sizeof(b));
+    }
+
+    /*
+     * Bind to local address.
+     */
+    if (sock->privport)
+	localport = 1023;	       /* count from 1023 downwards */
+    else
+	localport = 0;		       /* just use port 0 (ie winsock picks) */
+
+    /* Loop round trying to bind */
+    while (1) {
+	int sockcode;
+
+#ifndef NO_IPV6
+	if (family == AF_INET6) {
+	    memset(&a6, 0, sizeof(a6));
+	    a6.sin6_family = AF_INET6;
+          /*a6.sin6_addr = in6addr_any; */ /* == 0 done by memset() */
+	    a6.sin6_port = p_htons(localport);
+	} else
+#endif
+	{
+	    a.sin_family = AF_INET;
+	    a.sin_addr.s_addr = p_htonl(INADDR_ANY);
+	    a.sin_port = p_htons(localport);
+	}
+#ifndef NO_IPV6
+	sockcode = p_bind(s, (family == AF_INET6 ?
+			      (struct sockaddr *) &a6 :
+			      (struct sockaddr *) &a),
+			  (family == AF_INET6 ? sizeof(a6) : sizeof(a)));
+#else
+	sockcode = p_bind(s, (struct sockaddr *) &a, sizeof(a));
+#endif
+	if (sockcode != SOCKET_ERROR) {
+	    err = 0;
+	    break;		       /* done */
+	} else {
+	    err = p_WSAGetLastError();
+	    if (err != WSAEADDRINUSE)  /* failed, for a bad reason */
+		break;
+	}
+
+	if (localport == 0)
+	    break;		       /* we're only looping once */
+	localport--;
+	if (localport == 0)
+	    break;		       /* we might have got to the end */
+    }
+
+    if (err) {
+	sock->error = winsock_error_string(err);
+	goto ret;
+    }
+
+    /*
+     * Connect to remote address.
+     */
+#ifndef NO_IPV6
+    if (sock->step.ai) {
+	if (family == AF_INET6) {
+	    a6.sin6_family = AF_INET6;
+	    a6.sin6_port = p_htons((short) sock->port);
+	    a6.sin6_addr =
+		((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_addr;
+	    a6.sin6_flowinfo = ((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_flowinfo;
+	    a6.sin6_scope_id = ((struct sockaddr_in6 *) sock->step.ai->ai_addr)->sin6_scope_id;
+	} else {
+	    a.sin_family = AF_INET;
+	    a.sin_addr =
+		((struct sockaddr_in *) sock->step.ai->ai_addr)->sin_addr;
+	    a.sin_port = p_htons((short) sock->port);
+	}
+    } else
+#endif
+    {
+	assert(sock->addr->addresses && sock->step.curraddr < sock->addr->naddresses);
+	a.sin_family = AF_INET;
+	a.sin_addr.s_addr = p_htonl(sock->addr->addresses[sock->step.curraddr]);
+	a.sin_port = p_htons((short) sock->port);
+    }
+
+    /* Set up a select mechanism. This could be an AsyncSelect on a
+     * window, or an EventSelect on an event object. */
+    errstr = do_select(s, 1);
+    if (errstr) {
+	sock->error = errstr;
+	err = 1;
+	goto ret;
+    }
+
+    if ((
+#ifndef NO_IPV6
+	    p_connect(s,
+		      ((family == AF_INET6) ? (struct sockaddr *) &a6 :
+		       (struct sockaddr *) &a),
+		      (family == AF_INET6) ? sizeof(a6) : sizeof(a))
+#else
+	    p_connect(s, (struct sockaddr *) &a, sizeof(a))
+#endif
+	) == SOCKET_ERROR) {
+	err = p_WSAGetLastError();
+	/*
+	 * We expect a potential EWOULDBLOCK here, because the
+	 * chances are the front end has done a select for
+	 * FD_CONNECT, so that connect() will complete
+	 * asynchronously.
+	 */
+	if ( err != WSAEWOULDBLOCK ) {
+	    sock->error = winsock_error_string(err);
+	    goto ret;
+	}
+    } else {
+	/*
+	 * If we _don't_ get EWOULDBLOCK, the connect has completed
+	 * and we should set the socket as writable.
+	 */
+	sock->writable = 1;
+    }
+
+    err = 0;
+
+    ret:
+
+    /*
+     * No matter what happened, put the socket back in the tree.
+     */
+    add234(sktree, sock);
+
+    if (err)
+	plug_log(sock->plug, 1, sock->addr, sock->port, sock->error, err);
+    return err;
+}
+
+Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
+	      int nodelay, int keepalive, Plug plug)
+{
+    static const struct socket_function_table fn_table = {
+	sk_tcp_plug,
+	sk_tcp_close,
+	sk_tcp_write,
+	sk_tcp_write_oob,
+	sk_tcp_write_eof,
+	sk_tcp_flush,
+	sk_tcp_set_frozen,
+	sk_tcp_socket_error
+    };
+
+    Actual_Socket ret;
+    DWORD err;
+
+    /*
+     * Create Socket structure.
+     */
+    ret = snew(struct Socket_tag);
+    ret->fn = &fn_table;
+    ret->error = NULL;
+    ret->plug = plug;
+    bufchain_init(&ret->output_data);
+    ret->connected = 0;		       /* to start with */
+    ret->writable = 0;		       /* to start with */
+    ret->sending_oob = 0;
+    ret->outgoingeof = EOF_NO;
+    ret->frozen = 0;
+    ret->frozen_readable = 0;
+    ret->localhost_only = 0;	       /* unused, but best init anyway */
+    ret->pending_error = 0;
+    ret->parent = ret->child = NULL;
+    ret->oobinline = oobinline;
+    ret->nodelay = nodelay;
+    ret->keepalive = keepalive;
+    ret->privport = privport;
+    ret->port = port;
+    ret->addr = addr;
+    START_STEP(ret->addr, ret->step);
+    ret->s = INVALID_SOCKET;
+
+    err = 0;
+    do {
+        err = try_connect(ret);
+    } while (err && sk_nextaddr(ret->addr, &ret->step));
+
+    return (Socket) ret;
+}
+
+Socket sk_newlistener(char *srcaddr, int port, Plug plug, int local_host_only,
+		      int orig_address_family)
+{
+    static const struct socket_function_table fn_table = {
+	sk_tcp_plug,
+	sk_tcp_close,
+	sk_tcp_write,
+	sk_tcp_write_oob,
+	sk_tcp_write_eof,
+	sk_tcp_flush,
+	sk_tcp_set_frozen,
+	sk_tcp_socket_error
+    };
+
+    SOCKET s;
+#ifndef NO_IPV6
+    SOCKADDR_IN6 a6;
+#endif
+    SOCKADDR_IN a;
+
+    DWORD err;
+    char *errstr;
+    Actual_Socket ret;
+    int retcode;
+    int on = 1;
+
+    int address_family;
+
+    /*
+     * Create Socket structure.
+     */
+    ret = snew(struct Socket_tag);
+    ret->fn = &fn_table;
+    ret->error = NULL;
+    ret->plug = plug;
+    bufchain_init(&ret->output_data);
+    ret->writable = 0;		       /* to start with */
+    ret->sending_oob = 0;
+    ret->outgoingeof = EOF_NO;
+    ret->frozen = 0;
+    ret->frozen_readable = 0;
+    ret->localhost_only = local_host_only;
+    ret->pending_error = 0;
+    ret->parent = ret->child = NULL;
+    ret->addr = NULL;
+
+    /*
+     * Translate address_family from platform-independent constants
+     * into local reality.
+     */
+    address_family = (orig_address_family == ADDRTYPE_IPV4 ? AF_INET :
+#ifndef NO_IPV6
+		      orig_address_family == ADDRTYPE_IPV6 ? AF_INET6 :
+#endif
+		      AF_UNSPEC);
+
+    /*
+     * Our default, if passed the `don't care' value
+     * ADDRTYPE_UNSPEC, is to listen on IPv4. If IPv6 is supported,
+     * we will also set up a second socket listening on IPv6, but
+     * the v4 one is primary since that ought to work even on
+     * non-v6-supporting systems.
+     */
+    if (address_family == AF_UNSPEC) address_family = AF_INET;
+
+    /*
+     * Open socket.
+     */
+    s = p_socket(address_family, SOCK_STREAM, 0);
+    ret->s = s;
+
+    if (s == INVALID_SOCKET) {
+	err = p_WSAGetLastError();
+	ret->error = winsock_error_string(err);
+	return (Socket) ret;
+    }
+
+    ret->oobinline = 0;
+
+    p_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));
+
+#ifndef NO_IPV6
+	if (address_family == AF_INET6) {
+	    memset(&a6, 0, sizeof(a6));
+	    a6.sin6_family = AF_INET6;
+	    if (local_host_only)
+		a6.sin6_addr = in6addr_loopback;
+	    else
+		a6.sin6_addr = in6addr_any;
+            if (srcaddr != NULL && p_getaddrinfo) {
+                struct addrinfo hints;
+                struct addrinfo *ai;
+                int err;
+
+                memset(&hints, 0, sizeof(hints));
+                hints.ai_family = AF_INET6;
+                hints.ai_flags = 0;
+                {
+                    /* strip [] on IPv6 address literals */
+                    char *trimmed_addr = host_strduptrim(srcaddr);
+                    err = p_getaddrinfo(trimmed_addr, NULL, &hints, &ai);
+                    sfree(trimmed_addr);
+                }
+                if (err == 0 && ai->ai_family == AF_INET6) {
+                    a6.sin6_addr =
+                        ((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
+                }
+            }
+	    a6.sin6_port = p_htons(port);
+	} else
+#endif
+	{
+	    int got_addr = 0;
+	    a.sin_family = AF_INET;
+
+	    /*
+	     * Bind to source address. First try an explicitly
+	     * specified one...
+	     */
+	    if (srcaddr) {
+		a.sin_addr.s_addr = p_inet_addr(srcaddr);
+		if (a.sin_addr.s_addr != INADDR_NONE) {
+		    /* Override localhost_only with specified listen addr. */
+		    ret->localhost_only = ipv4_is_loopback(a.sin_addr);
+		    got_addr = 1;
+		}
+	    }
+
+	    /*
+	     * ... and failing that, go with one of the standard ones.
+	     */
+	    if (!got_addr) {
+		if (local_host_only)
+		    a.sin_addr.s_addr = p_htonl(INADDR_LOOPBACK);
+		else
+		    a.sin_addr.s_addr = p_htonl(INADDR_ANY);
+	    }
+
+	    a.sin_port = p_htons((short)port);
+	}
+#ifndef NO_IPV6
+	retcode = p_bind(s, (address_family == AF_INET6 ?
+			   (struct sockaddr *) &a6 :
+			   (struct sockaddr *) &a),
+		       (address_family ==
+			AF_INET6 ? sizeof(a6) : sizeof(a)));
+#else
+	retcode = p_bind(s, (struct sockaddr *) &a, sizeof(a));
+#endif
+	if (retcode != SOCKET_ERROR) {
+	    err = 0;
+	} else {
+	    err = p_WSAGetLastError();
+	}
+
+    if (err) {
+	p_closesocket(s);
+	ret->error = winsock_error_string(err);
+	return (Socket) ret;
+    }
+
+
+    if (p_listen(s, SOMAXCONN) == SOCKET_ERROR) {
+        p_closesocket(s);
+	ret->error = winsock_error_string(p_WSAGetLastError());
+	return (Socket) ret;
+    }
+
+    /* Set up a select mechanism. This could be an AsyncSelect on a
+     * window, or an EventSelect on an event object. */
+    errstr = do_select(s, 1);
+    if (errstr) {
+	p_closesocket(s);
+	ret->error = errstr;
+	return (Socket) ret;
+    }
+
+    add234(sktree, ret);
+
+#ifndef NO_IPV6
+    /*
+     * If we were given ADDRTYPE_UNSPEC, we must also create an
+     * IPv6 listening socket and link it to this one.
+     */
+    if (address_family == AF_INET && orig_address_family == ADDRTYPE_UNSPEC) {
+	Actual_Socket other;
+
+	other = (Actual_Socket) sk_newlistener(srcaddr, port, plug,
+					       local_host_only, ADDRTYPE_IPV6);
+
+	if (other) {
+	    if (!other->error) {
+		other->parent = ret;
+		ret->child = other;
+	    } else {
+		sfree(other);
+	    }
+	}
+    }
+#endif
+
+    return (Socket) ret;
+}
+
+static void sk_tcp_close(Socket sock)
+{
+    extern char *do_select(SOCKET skt, int startup);
+    Actual_Socket s = (Actual_Socket) sock;
+
+    if (s->child)
+	sk_tcp_close((Socket)s->child);
+
+    del234(sktree, s);
+    do_select(s->s, 0);
+    p_closesocket(s->s);
+    if (s->addr)
+	sk_addr_free(s->addr);
+    sfree(s);
+}
+
+/*
+ * Deal with socket errors detected in try_send().
+ */
+static void socket_error_callback(void *vs)
+{
+    Actual_Socket s = (Actual_Socket)vs;
+
+    /*
+     * Just in case other socket work has caused this socket to vanish
+     * or become somehow non-erroneous before this callback arrived...
+     */
+    if (!find234(sktree, s, NULL) || !s->pending_error)
+        return;
+
+    /*
+     * An error has occurred on this socket. Pass it to the plug.
+     */
+    plug_closing(s->plug, winsock_error_string(s->pending_error),
+                 s->pending_error, 0);
+}
+
+/*
+ * The function which tries to send on a socket once it's deemed
+ * writable.
+ */
+void try_send(Actual_Socket s)
+{
+    while (s->sending_oob || bufchain_size(&s->output_data) > 0) {
+	int nsent;
+	DWORD err;
+	void *data;
+	int len, urgentflag;
+
+	if (s->sending_oob) {
+	    urgentflag = MSG_OOB;
+	    len = s->sending_oob;
+	    data = &s->oobdata;
+	} else {
+	    urgentflag = 0;
+	    bufchain_prefix(&s->output_data, &data, &len);
+	}
+	nsent = p_send(s->s, data, len, urgentflag);
+	noise_ultralight(nsent);
+	if (nsent <= 0) {
+	    err = (nsent < 0 ? p_WSAGetLastError() : 0);
+	    if ((err < WSABASEERR && nsent < 0) || err == WSAEWOULDBLOCK) {
+		/*
+		 * Perfectly normal: we've sent all we can for the moment.
+		 * 
+		 * (Some WinSock send() implementations can return
+		 * <0 but leave no sensible error indication -
+		 * WSAGetLastError() is called but returns zero or
+		 * a small number - so we check that case and treat
+		 * it just like WSAEWOULDBLOCK.)
+		 */
+		s->writable = FALSE;
+		return;
+	    } else if (nsent == 0 ||
+		       err == WSAECONNABORTED || err == WSAECONNRESET) {
+		/*
+		 * If send() returns CONNABORTED or CONNRESET, we
+		 * unfortunately can't just call plug_closing(),
+		 * because it's quite likely that we're currently
+		 * _in_ a call from the code we'd be calling back
+		 * to, so we'd have to make half the SSH code
+		 * reentrant. Instead we flag a pending error on
+		 * the socket, to be dealt with (by calling
+		 * plug_closing()) at some suitable future moment.
+		 */
+		s->pending_error = err;
+                queue_toplevel_callback(socket_error_callback, s);
+		return;
+	    } else {
+		/* We're inside the Windows frontend here, so we know
+		 * that the frontend handle is unnecessary. */
+		logevent(NULL, winsock_error_string(err));
+		fatalbox("%s", winsock_error_string(err));
+	    }
+	} else {
+	    if (s->sending_oob) {
+		if (nsent < len) {
+		    memmove(s->oobdata, s->oobdata+nsent, len-nsent);
+		    s->sending_oob = len - nsent;
+		} else {
+		    s->sending_oob = 0;
+		}
+	    } else {
+		bufchain_consume(&s->output_data, nsent);
+	    }
+	}
+    }
+
+    /*
+     * If we reach here, we've finished sending everything we might
+     * have needed to send. Send EOF, if we need to.
+     */
+    if (s->outgoingeof == EOF_PENDING) {
+        p_shutdown(s->s, SD_SEND);
+        s->outgoingeof = EOF_SENT;
+    }
+}
+
+static int sk_tcp_write(Socket sock, const char *buf, int len)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+
+    assert(s->outgoingeof == EOF_NO);
+
+    /*
+     * Add the data to the buffer list on the socket.
+     */
+    bufchain_add(&s->output_data, buf, len);
+
+    /*
+     * Now try sending from the start of the buffer list.
+     */
+    if (s->writable)
+	try_send(s);
+
+    return bufchain_size(&s->output_data);
+}
+
+static int sk_tcp_write_oob(Socket sock, const char *buf, int len)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+
+    assert(s->outgoingeof == EOF_NO);
+
+    /*
+     * Replace the buffer list on the socket with the data.
+     */
+    bufchain_clear(&s->output_data);
+    assert(len <= sizeof(s->oobdata));
+    memcpy(s->oobdata, buf, len);
+    s->sending_oob = len;
+
+    /*
+     * Now try sending from the start of the buffer list.
+     */
+    if (s->writable)
+	try_send(s);
+
+    return s->sending_oob;
+}
+
+static void sk_tcp_write_eof(Socket sock)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+
+    assert(s->outgoingeof == EOF_NO);
+
+    /*
+     * Mark the socket as pending outgoing EOF.
+     */
+    s->outgoingeof = EOF_PENDING;
+
+    /*
+     * Now try sending from the start of the buffer list.
+     */
+    if (s->writable)
+	try_send(s);
+}
+
+int select_result(WPARAM wParam, LPARAM lParam)
+{
+    int ret, open;
+    DWORD err;
+    char buf[20480];		       /* nice big buffer for plenty of speed */
+    Actual_Socket s;
+    u_long atmark;
+
+    /* wParam is the socket itself */
+
+    if (wParam == 0)
+	return 1;		       /* boggle */
+
+    s = find234(sktree, (void *) wParam, cmpforsearch);
+    if (!s)
+	return 1;		       /* boggle */
+
+    if ((err = WSAGETSELECTERROR(lParam)) != 0) {
+	/*
+	 * An error has occurred on this socket. Pass it to the
+	 * plug.
+	 */
+	if (s->addr) {
+	    plug_log(s->plug, 1, s->addr, s->port,
+		     winsock_error_string(err), err);
+	    while (s->addr && sk_nextaddr(s->addr, &s->step)) {
+		err = try_connect(s);
+	    }
+	}
+	if (err != 0)
+	    return plug_closing(s->plug, winsock_error_string(err), err, 0);
+	else
+	    return 1;
+    }
+
+    noise_ultralight(lParam);
+
+    switch (WSAGETSELECTEVENT(lParam)) {
+      case FD_CONNECT:
+	s->connected = s->writable = 1;
+	/*
+	 * Once a socket is connected, we can stop falling
+	 * back through the candidate addresses to connect
+	 * to.
+	 */
+	if (s->addr) {
+	    sk_addr_free(s->addr);
+	    s->addr = NULL;
+	}
+	break;
+      case FD_READ:
+	/* In the case the socket is still frozen, we don't even bother */
+	if (s->frozen) {
+	    s->frozen_readable = 1;
+	    break;
+	}
+
+	/*
+	 * We have received data on the socket. For an oobinline
+	 * socket, this might be data _before_ an urgent pointer,
+	 * in which case we send it to the back end with type==1
+	 * (data prior to urgent).
+	 */
+	if (s->oobinline) {
+	    atmark = 1;
+	    p_ioctlsocket(s->s, SIOCATMARK, &atmark);
+	    /*
+	     * Avoid checking the return value from ioctlsocket(),
+	     * on the grounds that some WinSock wrappers don't
+	     * support it. If it does nothing, we get atmark==1,
+	     * which is equivalent to `no OOB pending', so the
+	     * effect will be to non-OOB-ify any OOB data.
+	     */
+	} else
+	    atmark = 1;
+
+	ret = p_recv(s->s, buf, sizeof(buf), 0);
+	noise_ultralight(ret);
+	if (ret < 0) {
+	    err = p_WSAGetLastError();
+	    if (err == WSAEWOULDBLOCK) {
+		break;
+	    }
+	}
+	if (ret < 0) {
+	    return plug_closing(s->plug, winsock_error_string(err), err,
+				0);
+	} else if (0 == ret) {
+	    return plug_closing(s->plug, NULL, 0, 0);
+	} else {
+	    return plug_receive(s->plug, atmark ? 0 : 1, buf, ret);
+	}
+	break;
+      case FD_OOB:
+	/*
+	 * This will only happen on a non-oobinline socket. It
+	 * indicates that we can immediately perform an OOB read
+	 * and get back OOB data, which we will send to the back
+	 * end with type==2 (urgent data).
+	 */
+	ret = p_recv(s->s, buf, sizeof(buf), MSG_OOB);
+	noise_ultralight(ret);
+	if (ret <= 0) {
+	    char *str = (ret == 0 ? "Internal networking trouble" :
+			 winsock_error_string(p_WSAGetLastError()));
+	    /* We're inside the Windows frontend here, so we know
+	     * that the frontend handle is unnecessary. */
+	    logevent(NULL, str);
+	    fatalbox("%s", str);
+	} else {
+	    return plug_receive(s->plug, 2, buf, ret);
+	}
+	break;
+      case FD_WRITE:
+	{
+	    int bufsize_before, bufsize_after;
+	    s->writable = 1;
+	    bufsize_before = s->sending_oob + bufchain_size(&s->output_data);
+	    try_send(s);
+	    bufsize_after = s->sending_oob + bufchain_size(&s->output_data);
+	    if (bufsize_after < bufsize_before)
+		plug_sent(s->plug, bufsize_after);
+	}
+	break;
+      case FD_CLOSE:
+	/* Signal a close on the socket. First read any outstanding data. */
+	open = 1;
+	do {
+	    ret = p_recv(s->s, buf, sizeof(buf), 0);
+	    if (ret < 0) {
+		err = p_WSAGetLastError();
+		if (err == WSAEWOULDBLOCK)
+		    break;
+		return plug_closing(s->plug, winsock_error_string(err),
+				    err, 0);
+	    } else {
+		if (ret)
+		    open &= plug_receive(s->plug, 0, buf, ret);
+		else
+		    open &= plug_closing(s->plug, NULL, 0, 0);
+	    }
+	} while (ret > 0);
+	return open;
+       case FD_ACCEPT:
+	{
+#ifdef NO_IPV6
+	    struct sockaddr_in isa;
+#else
+            struct sockaddr_storage isa;
+#endif
+	    int addrlen = sizeof(isa);
+	    SOCKET t;  /* socket of connection */
+            accept_ctx_t actx;
+
+	    memset(&isa, 0, sizeof(isa));
+	    err = 0;
+	    t = p_accept(s->s,(struct sockaddr *)&isa,&addrlen);
+	    if (t == INVALID_SOCKET)
+	    {
+		err = p_WSAGetLastError();
+		if (err == WSATRY_AGAIN)
+		    break;
+	    }
+
+            actx.p = (void *)t;
+
+#ifndef NO_IPV6
+            if (isa.ss_family == AF_INET &&
+                s->localhost_only &&
+                !ipv4_is_local_addr(((struct sockaddr_in *)&isa)->sin_addr))
+#else
+	    if (s->localhost_only && !ipv4_is_local_addr(isa.sin_addr))
+#endif
+	    {
+		p_closesocket(t);      /* dodgy WinSock let nonlocal through */
+	    } else if (plug_accepting(s->plug, sk_tcp_accept, actx)) {
+		p_closesocket(t);      /* denied or error */
+	    }
+	}
+    }
+
+    return 1;
+}
+
+/*
+ * Special error values are returned from sk_namelookup and sk_new
+ * if there's a problem. These functions extract an error message,
+ * or return NULL if there's no problem.
+ */
+const char *sk_addr_error(SockAddr addr)
+{
+    return addr->error;
+}
+static const char *sk_tcp_socket_error(Socket sock)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+    return s->error;
+}
+
+static void sk_tcp_set_frozen(Socket sock, int is_frozen)
+{
+    Actual_Socket s = (Actual_Socket) sock;
+    if (s->frozen == is_frozen)
+	return;
+    s->frozen = is_frozen;
+    if (!is_frozen) {
+	do_select(s->s, 1);
+	if (s->frozen_readable) {
+	    char c;
+	    p_recv(s->s, &c, 1, MSG_PEEK);
+	}
+    }
+    s->frozen_readable = 0;
+}
+
+void socket_reselect_all(void)
+{
+    Actual_Socket s;
+    int i;
+
+    for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
+	if (!s->frozen)
+	    do_select(s->s, 1);
+    }
+}
+
+/*
+ * For Plink: enumerate all sockets currently active.
+ */
+SOCKET first_socket(int *state)
+{
+    Actual_Socket s;
+    *state = 0;
+    s = index234(sktree, (*state)++);
+    return s ? s->s : INVALID_SOCKET;
+}
+
+SOCKET next_socket(int *state)
+{
+    Actual_Socket s = index234(sktree, (*state)++);
+    return s ? s->s : INVALID_SOCKET;
+}
+
+extern int socket_writable(SOCKET skt)
+{
+    Actual_Socket s = find234(sktree, (void *)skt, cmpforsearch);
+
+    if (s)
+	return bufchain_size(&s->output_data) > 0;
+    else
+	return 0;
+}
+
+int net_service_lookup(char *service)
+{
+    struct servent *se;
+    se = p_getservbyname(service, NULL);
+    if (se != NULL)
+	return p_ntohs(se->s_port);
+    else
+	return 0;
+}
+
+char *get_hostname(void)
+{
+    int len = 128;
+    char *hostname = NULL;
+    do {
+	len *= 2;
+	hostname = sresize(hostname, len, char);
+	if (p_gethostname(hostname, len) < 0) {
+	    sfree(hostname);
+	    hostname = NULL;
+	    break;
+	}
+    } while (strlen(hostname) >= (size_t)(len-1));
+    return hostname;
+}
+
+SockAddr platform_get_x11_unix_address(const char *display, int displaynum,
+				       char **canonicalname)
+{
+    SockAddr ret = snew(struct SockAddr_tag);
+    memset(ret, 0, sizeof(struct SockAddr_tag));
+    ret->error = "unix sockets not supported on this platform";
+    ret->refcount = 1;
+    return ret;
+}