2 * General mechanism for wrapping up reading/writing of Windows
3 * HANDLEs into a PuTTY Socket abstraction.
10 #define DEFINE_PLUG_METHOD_MACROS
15 typedef struct Socket_handle_tag *Handle_Socket;
17 struct Socket_handle_tag {
18 const struct socket_function_table *fn;
19 /* the above variable absolutely *must* be the first in this structure */
21 HANDLE send_H, recv_H;
22 struct handle *send_h, *recv_h;
25 * Freezing one of these sockets is a slightly fiddly business,
26 * because the reads from the handle are happening in a separate
27 * thread as blocking system calls and so once one is in progress
28 * it can't sensibly be interrupted. Hence, after the user tries
29 * to freeze one of these sockets, it's unavoidable that we may
30 * receive one more load of data before we manage to get
31 * winhandl.c to stop reading.
34 UNFROZEN, /* reading as normal */
35 FREEZING, /* have been set to frozen but winhandl is still reading */
36 FROZEN, /* really frozen - winhandl has been throttled */
37 THAWING /* we're gradually releasing our remaining data */
39 /* We buffer data here if we receive it from winhandl while frozen. */
47 static int handle_gotdata(struct handle *h, void *data, int len)
49 Handle_Socket ps = (Handle_Socket) handle_get_privdata(h);
52 return plug_closing(ps->plug, "Read error from handle",
54 } else if (len == 0) {
55 return plug_closing(ps->plug, NULL, 0, 0);
57 assert(ps->frozen != FREEZING && ps->frozen != THAWING);
58 if (ps->frozen == FREEZING) {
60 * If we've received data while this socket is supposed to
61 * be frozen (because the read winhandl.c started before
62 * sk_set_frozen was called has now returned) then buffer
63 * the data for when we unfreeze.
65 bufchain_add(&ps->inputdata, data, len);
68 * And return a very large backlog, to prevent further
69 * data arriving from winhandl until we unfreeze.
73 return plug_receive(ps->plug, 0, data, len);
78 static void handle_sentdata(struct handle *h, int new_backlog)
80 Handle_Socket ps = (Handle_Socket) handle_get_privdata(h);
82 plug_sent(ps->plug, new_backlog);
85 static Plug sk_handle_plug(Socket s, Plug p)
87 Handle_Socket ps = (Handle_Socket) s;
94 static void sk_handle_close(Socket s)
96 Handle_Socket ps = (Handle_Socket) s;
98 handle_free(ps->send_h);
99 handle_free(ps->recv_h);
100 CloseHandle(ps->send_H);
101 if (ps->recv_H != ps->send_H)
102 CloseHandle(ps->recv_H);
103 bufchain_clear(&ps->inputdata);
108 static int sk_handle_write(Socket s, const char *data, int len)
110 Handle_Socket ps = (Handle_Socket) s;
112 return handle_write(ps->send_h, data, len);
115 static int sk_handle_write_oob(Socket s, const char *data, int len)
118 * oob data is treated as inband; nasty, but nothing really
121 return sk_handle_write(s, data, len);
124 static void sk_handle_write_eof(Socket s)
126 Handle_Socket ps = (Handle_Socket) s;
128 handle_write_eof(ps->send_h);
131 static void sk_handle_flush(Socket s)
133 /* Handle_Socket ps = (Handle_Socket) s; */
137 static void handle_socket_unfreeze(void *psv)
139 Handle_Socket ps = (Handle_Socket) psv;
141 int len, new_backlog;
144 * If we've been put into a state other than THAWING since the
145 * last callback, then we're done.
147 if (ps->frozen != THAWING)
151 * Get some of the data we've buffered.
153 bufchain_prefix(&ps->inputdata, &data, &len);
157 * Hand it off to the plug.
159 new_backlog = plug_receive(ps->plug, 0, data, len);
161 if (bufchain_size(&ps->inputdata) > 0) {
163 * If there's still data in our buffer, stay in THAWING state,
164 * and reschedule ourself.
166 queue_toplevel_callback(handle_socket_unfreeze, ps);
169 * Otherwise, we've successfully thawed!
171 ps->frozen = UNFROZEN;
172 handle_unthrottle(ps->recv_h, new_backlog);
176 static void sk_handle_set_frozen(Socket s, int is_frozen)
178 Handle_Socket ps = (Handle_Socket) s;
181 switch (ps->frozen) {
184 return; /* nothing to do */
188 * We were in the middle of emptying our bufchain, and got
189 * frozen again. In that case, winhandl.c is already
190 * throttled, so just return to FROZEN state. The toplevel
191 * callback will notice and disable itself.
198 * The normal case. Go to FREEZING, and expect one more
199 * load of data from winhandl if we're unlucky.
201 ps->frozen = FREEZING;
205 switch (ps->frozen) {
208 return; /* nothing to do */
212 * If winhandl didn't send us any data throughout the time
213 * we were frozen, then we'll still be in this state and
214 * can just unfreeze in the trivial way.
216 assert(bufchain_size(&ps->inputdata) == 0);
217 ps->frozen = UNFROZEN;
222 * If we have buffered data, go to THAWING and start
223 * releasing it in top-level callbacks.
225 ps->frozen = THAWING;
226 queue_toplevel_callback(handle_socket_unfreeze, ps);
231 static const char *sk_handle_socket_error(Socket s)
233 Handle_Socket ps = (Handle_Socket) s;
237 Socket make_handle_socket(HANDLE send_H, HANDLE recv_H, Plug plug,
240 static const struct socket_function_table socket_fn_table = {
247 sk_handle_set_frozen,
248 sk_handle_socket_error
252 int flags = (overlapped ? HANDLE_FLAG_OVERLAPPED : 0);
254 ret = snew(struct Socket_handle_tag);
255 ret->fn = &socket_fn_table;
258 ret->frozen = UNFROZEN;
259 bufchain_init(&ret->inputdata);
261 ret->recv_H = recv_H;
262 ret->recv_h = handle_input_new(ret->recv_H, handle_gotdata, ret, flags);
263 ret->send_H = send_H;
264 ret->send_h = handle_output_new(ret->send_H, handle_sentdata, ret, flags);