2 * Windows networking abstraction.
4 * Due to this clean abstraction it was possible
5 * to easily implement IPv6 support :)
7 * IPv6 patch 1 (27 October 2000) Jeroen Massar <jeroen@unfix.org>
8 * - Preliminary hacked IPv6 support.
9 * - Connecting to IPv6 address (eg fec0:4242:4242:100:2d0:b7ff:fe8f:5d42) works.
10 * - Connecting to IPv6 hostname (eg heaven.ipv6.unfix.org) works.
11 * - Compiles as either IPv4 or IPv6.
13 * IPv6 patch 2 (29 October 2000) Jeroen Massar <jeroen@unfix.org>
14 * - When compiled as IPv6 it also allows connecting to IPv4 hosts.
15 * - Added some more documentation.
17 * IPv6 patch 3 (18 November 2000) Jeroen Massar <jeroen@unfix.org>
18 * - It now supports dynamically loading the IPv6 resolver dll's.
19 * This way we should be able to distribute one (1) binary
20 * which supports both IPv4 and IPv6.
21 * - getaddrinfo() and getnameinfo() are loaded dynamicaly if possible.
22 * - in6addr_any is defined in this file so we don't need to link to wship6.lib
23 * - The patch is now more unified so that we can still
24 * remove all IPv6 support by undef'ing IPV6.
25 * But where it fallsback to IPv4 it uses the IPv4 code which is already in place...
26 * - Canonical name resolving works.
28 * IPv6 patch 4 (07 January 2001) Jeroen Massar <jeroen@unfix.org>
29 * - patch against CVS of today, will be submitted to the bugs list
30 * as a 'cvs diff -u' on Simon's request...
35 * Define IPV6 to have IPv6 on-the-fly-loading support.
36 * This means that one doesn't have to have an IPv6 stack to use it.
37 * But if an IPv6 stack is found it is used with a fallback to IPv4.
53 #define DEFINE_PLUG_METHOD_MACROS
59 struct socket_function_table *fn;
60 /* the above variable absolutely *must* be the first in this structure */
68 int frozen; /* this causes readability notifications to be ignored */
69 int frozen_readable; /* this means we missed at least one readability
70 * notification while we were frozen */
71 int localhost_only; /* for listening sockets */
75 int pending_error; /* in case send() returns error */
79 * We used to typedef struct Socket_tag *Socket.
81 * Since we have made the networking abstraction slightly more
82 * abstract, Socket no longer means a tcp socket (it could mean
83 * an ssl socket). So now we must use Actual_Socket when we know
84 * we are talking about a tcp socket.
86 typedef struct Socket_tag *Actual_Socket;
90 /* address family this belongs to, AF_INET for IPv4, AF_INET6 for IPv6. */
92 unsigned long address; /* Address IPv4 style. */
94 struct addrinfo *ai; /* Address IPv6 style. */
98 static tree234 *sktree;
100 static int cmpfortree(void *av, void *bv)
102 Actual_Socket a = (Actual_Socket) av, b = (Actual_Socket) bv;
103 unsigned long as = (unsigned long) a->s, bs = (unsigned long) b->s;
111 static int cmpforsearch(void *av, void *bv)
113 Actual_Socket b = (Actual_Socket) bv;
114 unsigned long as = (unsigned long) av, bs = (unsigned long) b->s;
124 sktree = newtree234(cmpfortree);
127 char *winsock_error_string(int error)
131 return "Network error: Permission denied";
133 return "Network error: Address already in use";
134 case WSAEADDRNOTAVAIL:
135 return "Network error: Cannot assign requested address";
136 case WSAEAFNOSUPPORT:
138 "Network error: Address family not supported by protocol family";
140 return "Network error: Operation already in progress";
141 case WSAECONNABORTED:
142 return "Network error: Software caused connection abort";
143 case WSAECONNREFUSED:
144 return "Network error: Connection refused";
146 return "Network error: Connection reset by peer";
147 case WSAEDESTADDRREQ:
148 return "Network error: Destination address required";
150 return "Network error: Bad address";
152 return "Network error: Host is down";
153 case WSAEHOSTUNREACH:
154 return "Network error: No route to host";
156 return "Network error: Operation now in progress";
158 return "Network error: Interrupted function call";
160 return "Network error: Invalid argument";
162 return "Network error: Socket is already connected";
164 return "Network error: Too many open files";
166 return "Network error: Message too long";
168 return "Network error: Network is down";
170 return "Network error: Network dropped connection on reset";
172 return "Network error: Network is unreachable";
174 return "Network error: No buffer space available";
176 return "Network error: Bad protocol option";
178 return "Network error: Socket is not connected";
180 return "Network error: Socket operation on non-socket";
182 return "Network error: Operation not supported";
183 case WSAEPFNOSUPPORT:
184 return "Network error: Protocol family not supported";
186 return "Network error: Too many processes";
187 case WSAEPROTONOSUPPORT:
188 return "Network error: Protocol not supported";
190 return "Network error: Protocol wrong type for socket";
192 return "Network error: Cannot send after socket shutdown";
193 case WSAESOCKTNOSUPPORT:
194 return "Network error: Socket type not supported";
196 return "Network error: Connection timed out";
198 return "Network error: Resource temporarily unavailable";
200 return "Network error: Graceful shutdown in progress";
202 return "Unknown network error";
206 SockAddr sk_namelookup(char *host, char **canonicalname)
208 SockAddr ret = smalloc(sizeof(struct SockAddr_tag));
210 struct hostent *h = NULL;
213 /* Clear the structure and default to IPv4. */
214 memset(ret, 0, sizeof(struct SockAddr_tag));
215 ret->family = 0; /* We set this one when we have resolved the host. */
218 if ((a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
221 /* Try to get the getaddrinfo() function from wship6.dll */
222 /* This way one doesn't need to have IPv6 dll's to use PuTTY and
223 * it will fallback to IPv4. */
224 typedef int (CALLBACK * FGETADDRINFO) (const char *nodename,
225 const char *servname,
226 const struct addrinfo *
228 struct addrinfo ** res);
229 FGETADDRINFO fGetAddrInfo = NULL;
231 HINSTANCE dllWSHIP6 = LoadLibrary("wship6.dll");
233 fGetAddrInfo = (FGETADDRINFO) GetProcAddress(dllWSHIP6,
237 * Use fGetAddrInfo when it's available (which usually also
238 * means IPv6 is installed...)
241 /*debug(("Resolving \"%s\" with getaddrinfo() (IPv4+IPv6 capable)...\n", host)); */
242 if (fGetAddrInfo(host, NULL, NULL, &ret->ai) == 0)
243 ret->family = ret->ai->ai_family;
248 * Otherwise use the IPv4-only gethostbyname...
249 * (NOTE: we don't use gethostbyname as a
252 if (ret->family == 0) {
253 /*debug(("Resolving \"%s\" with gethostbyname() (IPv4 only)...\n", host)); */
254 if ( (h = gethostbyname(host)) )
255 ret->family = AF_INET;
258 /*debug(("Done resolving...(family is %d) AF_INET = %d, AF_INET6 = %d\n", ret->family, AF_INET, AF_INET6)); */
260 if (ret->family == 0) {
261 DWORD err = WSAGetLastError();
262 ret->error = (err == WSAENETDOWN ? "Network is down" :
264 WSAHOST_NOT_FOUND ? "Host does not exist" : err
265 == WSATRY_AGAIN ? "Host not found" :
267 fGetAddrInfo ? "getaddrinfo: unknown error" :
269 "gethostbyname: unknown error");
273 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
274 FORMAT_MESSAGE_FROM_SYSTEM |
275 FORMAT_MESSAGE_IGNORE_INSERTS, NULL, err,
276 MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
277 (LPTSTR) & lpMsgBuf, 0, NULL);
278 /*debug(("Error %ld: %s (h=%lx)\n", err, lpMsgBuf, h)); */
279 /* Free the buffer. */
287 /* If we got an address info use that... */
289 typedef int (CALLBACK * FGETNAMEINFO)
290 (const struct sockaddr FAR * sa, socklen_t salen,
291 char FAR * host, size_t hostlen, char FAR * serv,
292 size_t servlen, int flags);
293 FGETNAMEINFO fGetNameInfo = NULL;
295 /* Are we in IPv4 fallback mode? */
296 /* We put the IPv4 address into the a variable so we can further-on use the IPv4 code... */
297 if (ret->family == AF_INET)
299 (char *) &((SOCKADDR_IN *) ret->ai->
300 ai_addr)->sin_addr, sizeof(a));
302 /* Now let's find that canonicalname... */
305 (FGETNAMEINFO) GetProcAddress(dllWSHIP6,
308 ((struct sockaddr *) ret->ai->ai_addr,
310 AF_INET ? sizeof(SOCKADDR_IN) :
311 sizeof(SOCKADDR_IN6), realhost,
312 sizeof(realhost), NULL, 0, 0) != 0) {
313 strncpy(realhost, host, sizeof(realhost));
317 /* We used the IPv4-only gethostbyname()... */
321 memcpy(&a, h->h_addr, sizeof(a));
322 /* This way we are always sure the h->h_name is valid :) */
323 strncpy(realhost, h->h_name, sizeof(realhost));
327 FreeLibrary(dllWSHIP6);
331 * This must be a numeric IPv4 address because it caused a
332 * success return from inet_addr.
334 ret->family = AF_INET;
335 strncpy(realhost, host, sizeof(realhost));
337 ret->address = ntohl(a);
338 realhost[lenof(realhost)-1] = '\0';
339 *canonicalname = smalloc(1+strlen(realhost));
340 strcpy(*canonicalname, realhost);
344 void sk_getaddr(SockAddr addr, char *buf, int buflen)
347 if (addr->family == AF_INET) {
350 a.s_addr = htonl(addr->address);
351 strncpy(buf, inet_ntoa(a), buflen);
354 FIXME; /* I don't know how to get a text form of an IPv6 address. */
359 void sk_addr_free(SockAddr addr)
364 static Plug sk_tcp_plug(Socket sock, Plug p)
366 Actual_Socket s = (Actual_Socket) sock;
373 static void sk_tcp_flush(Socket s)
376 * We send data to the socket as soon as we can anyway,
377 * so we don't need to do anything here. :-)
381 static void sk_tcp_close(Socket s);
382 static int sk_tcp_write(Socket s, char *data, int len);
383 static int sk_tcp_write_oob(Socket s, char *data, int len);
384 static char *sk_tcp_socket_error(Socket s);
386 extern char *do_select(SOCKET skt, int startup);
388 Socket sk_register(void *sock, Plug plug)
390 static struct socket_function_table fn_table = {
404 * Create Socket structure.
406 ret = smalloc(sizeof(struct Socket_tag));
410 bufchain_init(&ret->output_data);
411 ret->writable = 1; /* to start with */
412 ret->sending_oob = 0;
414 ret->frozen_readable = 0;
415 ret->localhost_only = 0; /* unused, but best init anyway */
416 ret->pending_error = 0;
418 ret->s = (SOCKET)sock;
420 if (ret->s == INVALID_SOCKET) {
421 err = WSAGetLastError();
422 ret->error = winsock_error_string(err);
428 /* Set up a select mechanism. This could be an AsyncSelect on a
429 * window, or an EventSelect on an event object. */
430 errstr = do_select(ret->s, 1);
441 Socket sk_new(SockAddr addr, int port, int privport, int oobinline,
444 static struct socket_function_table fn_table = {
464 * Create Socket structure.
466 ret = smalloc(sizeof(struct Socket_tag));
470 bufchain_init(&ret->output_data);
471 ret->connected = 0; /* to start with */
472 ret->writable = 0; /* to start with */
473 ret->sending_oob = 0;
475 ret->frozen_readable = 0;
476 ret->localhost_only = 0; /* unused, but best init anyway */
477 ret->pending_error = 0;
482 s = socket(addr->family, SOCK_STREAM, 0);
485 if (s == INVALID_SOCKET) {
486 err = WSAGetLastError();
487 ret->error = winsock_error_string(err);
491 ret->oobinline = oobinline;
494 setsockopt(s, SOL_SOCKET, SO_OOBINLINE, (void *) &b, sizeof(b));
498 * Bind to local address.
501 localport = 1023; /* count from 1023 downwards */
503 localport = 0; /* just use port 0 (ie winsock picks) */
505 /* Loop round trying to bind */
510 if (addr->family == AF_INET6) {
511 memset(&a6, 0, sizeof(a6));
512 a6.sin6_family = AF_INET6;
513 /*a6.sin6_addr = in6addr_any; *//* == 0 */
514 a6.sin6_port = htons(localport);
518 a.sin_family = AF_INET;
519 a.sin_addr.s_addr = htonl(INADDR_ANY);
520 a.sin_port = htons(localport);
523 retcode = bind(s, (addr->family == AF_INET6 ?
524 (struct sockaddr *) &a6 :
525 (struct sockaddr *) &a),
527 AF_INET6 ? sizeof(a6) : sizeof(a)));
529 retcode = bind(s, (struct sockaddr *) &a, sizeof(a));
531 if (retcode != SOCKET_ERROR) {
535 err = WSAGetLastError();
536 if (err != WSAEADDRINUSE) /* failed, for a bad reason */
541 break; /* we're only looping once */
544 break; /* we might have got to the end */
548 ret->error = winsock_error_string(err);
553 * Connect to remote address.
556 if (addr->family == AF_INET6) {
557 memset(&a, 0, sizeof(a));
558 a6.sin6_family = AF_INET6;
559 a6.sin6_port = htons((short) port);
561 ((struct sockaddr_in6 *) addr->ai->ai_addr)->sin6_addr;
565 a.sin_family = AF_INET;
566 a.sin_addr.s_addr = htonl(addr->address);
567 a.sin_port = htons((short) port);
570 /* Set up a select mechanism. This could be an AsyncSelect on a
571 * window, or an EventSelect on an event object. */
572 errstr = do_select(s, 1);
580 connect(s, ((addr->family == AF_INET6) ?
581 (struct sockaddr *) &a6 : (struct sockaddr *) &a),
582 (addr->family == AF_INET6) ? sizeof(a6) : sizeof(a))
584 connect(s, (struct sockaddr *) &a, sizeof(a))
587 err = WSAGetLastError();
589 * We expect a potential EWOULDBLOCK here, because the
590 * chances are the front end has done a select for
591 * FD_CONNECT, so that connect() will complete
594 if ( err != WSAEWOULDBLOCK ) {
595 ret->error = winsock_error_string(err);
600 * If we _don't_ get EWOULDBLOCK, the connect has completed
601 * and we should set the socket as writable.
611 Socket sk_newlistener(int port, Plug plug, int local_host_only)
613 static struct socket_function_table fn_table = {
634 * Create Socket structure.
636 ret = smalloc(sizeof(struct Socket_tag));
640 bufchain_init(&ret->output_data);
641 ret->writable = 0; /* to start with */
642 ret->sending_oob = 0;
644 ret->frozen_readable = 0;
645 ret->localhost_only = local_host_only;
646 ret->pending_error = 0;
651 s = socket(AF_INET, SOCK_STREAM, 0);
654 if (s == INVALID_SOCKET) {
655 err = WSAGetLastError();
656 ret->error = winsock_error_string(err);
663 setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&on, sizeof(on));
667 if (addr->family == AF_INET6) {
668 memset(&a6, 0, sizeof(a6));
669 a6.sin6_family = AF_INET6;
671 a6.sin6_addr = in6addr_loopback;
673 a6.sin6_addr = in6addr_any;
674 a6.sin6_port = htons(port);
678 a.sin_family = AF_INET;
680 a.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
682 a.sin_addr.s_addr = htonl(INADDR_ANY);
683 a.sin_port = htons((short)port);
686 retcode = bind(s, (addr->family == AF_INET6 ?
687 (struct sockaddr *) &a6 :
688 (struct sockaddr *) &a),
690 AF_INET6 ? sizeof(a6) : sizeof(a)));
692 retcode = bind(s, (struct sockaddr *) &a, sizeof(a));
694 if (retcode != SOCKET_ERROR) {
697 err = WSAGetLastError();
701 ret->error = winsock_error_string(err);
706 if (listen(s, SOMAXCONN) == SOCKET_ERROR) {
708 ret->error = winsock_error_string(err);
712 /* Set up a select mechanism. This could be an AsyncSelect on a
713 * window, or an EventSelect on an event object. */
714 errstr = do_select(s, 1);
725 static void sk_tcp_close(Socket sock)
727 extern char *do_select(SOCKET skt, int startup);
728 Actual_Socket s = (Actual_Socket) sock;
737 * The function which tries to send on a socket once it's deemed
740 void try_send(Actual_Socket s)
742 while (s->sending_oob || bufchain_size(&s->output_data) > 0) {
748 if (s->sending_oob) {
749 urgentflag = MSG_OOB;
750 len = s->sending_oob;
754 bufchain_prefix(&s->output_data, &data, &len);
756 nsent = send(s->s, data, len, urgentflag);
757 noise_ultralight(nsent);
759 err = (nsent < 0 ? WSAGetLastError() : 0);
760 if ((err < WSABASEERR && nsent < 0) || err == WSAEWOULDBLOCK) {
762 * Perfectly normal: we've sent all we can for the moment.
764 * (Some WinSock send() implementations can return
765 * <0 but leave no sensible error indication -
766 * WSAGetLastError() is called but returns zero or
767 * a small number - so we check that case and treat
768 * it just like WSAEWOULDBLOCK.)
772 } else if (nsent == 0 ||
773 err == WSAECONNABORTED || err == WSAECONNRESET) {
775 * If send() returns CONNABORTED or CONNRESET, we
776 * unfortunately can't just call plug_closing(),
777 * because it's quite likely that we're currently
778 * _in_ a call from the code we'd be calling back
779 * to, so we'd have to make half the SSH code
780 * reentrant. Instead we flag a pending error on
781 * the socket, to be dealt with (by calling
782 * plug_closing()) at some suitable future moment.
784 s->pending_error = err;
787 fatalbox(winsock_error_string(err));
790 if (s->sending_oob) {
792 memmove(s->oobdata, s->oobdata+nsent, len-nsent);
793 s->sending_oob = len - nsent;
798 bufchain_consume(&s->output_data, nsent);
804 static int sk_tcp_write(Socket sock, char *buf, int len)
806 Actual_Socket s = (Actual_Socket) sock;
809 * Add the data to the buffer list on the socket.
811 bufchain_add(&s->output_data, buf, len);
814 * Now try sending from the start of the buffer list.
819 return bufchain_size(&s->output_data);
822 static int sk_tcp_write_oob(Socket sock, char *buf, int len)
824 Actual_Socket s = (Actual_Socket) sock;
827 * Replace the buffer list on the socket with the data.
829 bufchain_clear(&s->output_data);
830 assert(len <= sizeof(s->oobdata));
831 memcpy(s->oobdata, buf, len);
832 s->sending_oob = len;
835 * Now try sending from the start of the buffer list.
840 return s->sending_oob;
843 int select_result(WPARAM wParam, LPARAM lParam)
847 char buf[20480]; /* nice big buffer for plenty of speed */
851 /* wParam is the socket itself */
852 s = find234(sktree, (void *) wParam, cmpforsearch);
854 return 1; /* boggle */
856 if ((err = WSAGETSELECTERROR(lParam)) != 0) {
858 * An error has occurred on this socket. Pass it to the
861 return plug_closing(s->plug, winsock_error_string(err), err, 0);
864 noise_ultralight(lParam);
866 switch (WSAGETSELECTEVENT(lParam)) {
868 s->connected = s->writable = 1;
871 /* In the case the socket is still frozen, we don't even bother */
873 s->frozen_readable = 1;
878 * We have received data on the socket. For an oobinline
879 * socket, this might be data _before_ an urgent pointer,
880 * in which case we send it to the back end with type==1
881 * (data prior to urgent).
885 ioctlsocket(s->s, SIOCATMARK, &atmark);
887 * Avoid checking the return value from ioctlsocket(),
888 * on the grounds that some WinSock wrappers don't
889 * support it. If it does nothing, we get atmark==1,
890 * which is equivalent to `no OOB pending', so the
891 * effect will be to non-OOB-ify any OOB data.
896 ret = recv(s->s, buf, sizeof(buf), 0);
897 noise_ultralight(ret);
899 err = WSAGetLastError();
900 if (err == WSAEWOULDBLOCK) {
905 return plug_closing(s->plug, winsock_error_string(err), err,
907 } else if (0 == ret) {
908 return plug_closing(s->plug, NULL, 0, 0);
910 return plug_receive(s->plug, atmark ? 0 : 1, buf, ret);
915 * This will only happen on a non-oobinline socket. It
916 * indicates that we can immediately perform an OOB read
917 * and get back OOB data, which we will send to the back
918 * end with type==2 (urgent data).
920 ret = recv(s->s, buf, sizeof(buf), MSG_OOB);
921 noise_ultralight(ret);
923 fatalbox(ret == 0 ? "Internal networking trouble" :
924 winsock_error_string(WSAGetLastError()));
926 return plug_receive(s->plug, 2, buf, ret);
931 int bufsize_before, bufsize_after;
933 bufsize_before = s->sending_oob + bufchain_size(&s->output_data);
935 bufsize_after = s->sending_oob + bufchain_size(&s->output_data);
936 if (bufsize_after < bufsize_before)
937 plug_sent(s->plug, bufsize_after);
941 /* Signal a close on the socket. First read any outstanding data. */
944 ret = recv(s->s, buf, sizeof(buf), 0);
946 err = WSAGetLastError();
947 if (err == WSAEWOULDBLOCK)
949 return plug_closing(s->plug, winsock_error_string(err),
953 open &= plug_receive(s->plug, 0, buf, ret);
955 open &= plug_closing(s->plug, NULL, 0, 0);
961 struct sockaddr_in isa;
962 int addrlen = sizeof(struct sockaddr_in);
963 SOCKET t; /* socket of connection */
965 memset(&isa, 0, sizeof(struct sockaddr_in));
967 t = accept(s->s,&isa,&addrlen);
968 if (t == INVALID_SOCKET)
970 err = WSAGetLastError();
971 if (err == WSATRY_AGAIN)
975 if (s->localhost_only &&
976 ntohl(isa.sin_addr.s_addr) != INADDR_LOOPBACK) {
977 closesocket(t); /* dodgy WinSock let nonlocal through */
978 } else if (plug_accepting(s->plug, (void*)t)) {
979 closesocket(t); /* denied or error */
988 * Deal with socket errors detected in try_send().
990 void net_pending_errors(void)
996 * This might be a fiddly business, because it's just possible
997 * that handling a pending error on one socket might cause
998 * others to be closed. (I can't think of any reason this might
999 * happen in current SSH implementation, but to maintain
1000 * generality of this network layer I'll assume the worst.)
1002 * So what we'll do is search the socket list for _one_ socket
1003 * with a pending error, and then handle it, and then search
1004 * the list again _from the beginning_. Repeat until we make a
1005 * pass with no socket errors present. That way we are
1006 * protected against the socket list changing under our feet.
1010 for (i = 0; (s = index234(sktree, i)) != NULL; i++) {
1011 if (s->pending_error) {
1013 * An error has occurred on this socket. Pass it to the
1016 plug_closing(s->plug,
1017 winsock_error_string(s->pending_error),
1018 s->pending_error, 0);
1026 * Each socket abstraction contains a `void *' private field in
1027 * which the client can keep state.
1029 void sk_set_private_ptr(Socket sock, void *ptr)
1031 Actual_Socket s = (Actual_Socket) sock;
1032 s->private_ptr = ptr;
1035 void *sk_get_private_ptr(Socket sock)
1037 Actual_Socket s = (Actual_Socket) sock;
1038 return s->private_ptr;
1042 * Special error values are returned from sk_namelookup and sk_new
1043 * if there's a problem. These functions extract an error message,
1044 * or return NULL if there's no problem.
1046 char *sk_addr_error(SockAddr addr)
1050 static char *sk_tcp_socket_error(Socket sock)
1052 Actual_Socket s = (Actual_Socket) sock;
1056 void sk_set_frozen(Socket sock, int is_frozen)
1058 Actual_Socket s = (Actual_Socket) sock;
1059 if (s->frozen == is_frozen)
1061 s->frozen = is_frozen;
1062 if (!is_frozen && s->frozen_readable) {
1064 recv(s->s, &c, 1, MSG_PEEK);
1066 s->frozen_readable = 0;
1070 * For Plink: enumerate all sockets currently active.
1072 SOCKET first_socket(int *state)
1076 s = index234(sktree, (*state)++);
1077 return s ? s->s : INVALID_SOCKET;
1080 SOCKET next_socket(int *state)
1082 Actual_Socket s = index234(sktree, (*state)++);
1083 return s ? s->s : INVALID_SOCKET;