Merge tag 'pull-target-arm-20220922' of https://git.linaro.org/people/pmaydell/qemu...
[qemu.git] / hw / char / terminal3270.c
1 /*
2 * Terminal 3270 implementation
3 *
4 * Copyright 2017 IBM Corp.
5 *
6 * Authors: Yang Chen <bjcyang@linux.vnet.ibm.com>
7 * Jing Liu <liujbjl@linux.vnet.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or (at
10 * your option) any later version. See the COPYING file in the top-level
11 * directory.
12 */
13
14 #include "qemu/osdep.h"
15 #include "qapi/error.h"
16 #include "qemu/module.h"
17 #include "chardev/char-fe.h"
18 #include "hw/qdev-properties.h"
19 #include "hw/qdev-properties-system.h"
20 #include "hw/s390x/3270-ccw.h"
21 #include "qom/object.h"
22
23 /* Enough spaces for different window sizes. */
24 #define INPUT_BUFFER_SIZE 1000
25 /*
26 * 1 for header, 1024*2 for datastream, 2 for tail
27 * Reserve enough spaces for telnet IAC escape.
28 */
29 #define OUTPUT_BUFFER_SIZE 2051
30
31 struct Terminal3270 {
32 EmulatedCcw3270Device cdev;
33 CharBackend chr;
34 uint8_t inv[INPUT_BUFFER_SIZE];
35 uint8_t outv[OUTPUT_BUFFER_SIZE];
36 int in_len;
37 bool handshake_done;
38 guint timer_tag;
39 };
40 typedef struct Terminal3270 Terminal3270;
41
42 #define TYPE_TERMINAL_3270 "x-terminal3270"
43 DECLARE_INSTANCE_CHECKER(Terminal3270, TERMINAL_3270,
44 TYPE_TERMINAL_3270)
45
46 static int terminal_can_read(void *opaque)
47 {
48 Terminal3270 *t = opaque;
49
50 return INPUT_BUFFER_SIZE - t->in_len;
51 }
52
53 static void terminal_timer_cancel(Terminal3270 *t)
54 {
55 if (t->timer_tag) {
56 g_source_remove(t->timer_tag);
57 t->timer_tag = 0;
58 }
59 }
60
61 /*
62 * Protocol handshake done,
63 * signal guest by an unsolicited DE irq.
64 */
65 static void TN3270_handshake_done(Terminal3270 *t)
66 {
67 CcwDevice *ccw_dev = CCW_DEVICE(t);
68 SubchDev *sch = ccw_dev->sch;
69
70 t->handshake_done = true;
71 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END;
72 css_conditional_io_interrupt(sch);
73 }
74
75 /*
76 * Called when the interval is timeout to detect
77 * if the client is still alive by Timing Mark.
78 */
79 static gboolean send_timing_mark_cb(gpointer opaque)
80 {
81 Terminal3270 *t = opaque;
82 const uint8_t timing[] = {0xff, 0xfd, 0x06};
83
84 qemu_chr_fe_write_all(&t->chr, timing, sizeof(timing));
85 return true;
86 }
87
88 /*
89 * Receive inbound data from socket.
90 * For data given to guest, drop the data boundary IAC, IAC_EOR.
91 * TODO:
92 * Using "Reset" key on x3270 may result multiple commands in one packet.
93 * This usually happens when the user meets a poor traffic of the network.
94 * As of now, for such case, we simply terminate the connection,
95 * and we should come back here later with a better solution.
96 */
97 static void terminal_read(void *opaque, const uint8_t *buf, int size)
98 {
99 Terminal3270 *t = opaque;
100 CcwDevice *ccw_dev = CCW_DEVICE(t);
101 SubchDev *sch = ccw_dev->sch;
102 int end;
103
104 assert(size <= (INPUT_BUFFER_SIZE - t->in_len));
105
106 terminal_timer_cancel(t);
107 t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t);
108 memcpy(&t->inv[t->in_len], buf, size);
109 t->in_len += size;
110 if (t->in_len < 2) {
111 return;
112 }
113
114 if (!t->handshake_done) {
115 /*
116 * Receiving Terminal Type is the last step of handshake.
117 * The data format: IAC SB Terminal-Type IS <terminal type> IAC SE
118 * The code for Terminal-Type is 0x18, for IS is 0.
119 * Simply check the data format and mark handshake_done.
120 */
121 if (t->in_len > 6 && t->inv[2] == 0x18 && t->inv[3] == 0x0 &&
122 t->inv[t->in_len - 2] == IAC && t->inv[t->in_len - 1] == IAC_SE) {
123 TN3270_handshake_done(t);
124 t->in_len = 0;
125 }
126 return;
127 }
128
129 for (end = 0; end < t->in_len - 1; end++) {
130 if (t->inv[end] == IAC && t->inv[end + 1] == IAC_EOR) {
131 break;
132 }
133 }
134 if (end == t->in_len - 2) {
135 /* Data is valid for consuming. */
136 t->in_len -= 2;
137 sch->curr_status.scsw.dstat = SCSW_DSTAT_ATTENTION;
138 css_conditional_io_interrupt(sch);
139 } else if (end < t->in_len - 2) {
140 /* "Reset" key is used. */
141 qemu_chr_fe_disconnect(&t->chr);
142 } else {
143 /* Gathering data. */
144 return;
145 }
146 }
147
148 static void chr_event(void *opaque, QEMUChrEvent event)
149 {
150 Terminal3270 *t = opaque;
151 CcwDevice *ccw_dev = CCW_DEVICE(t);
152 SubchDev *sch = ccw_dev->sch;
153
154 /* Ensure the initial status correct, always reset them. */
155 t->in_len = 0;
156 t->handshake_done = false;
157 terminal_timer_cancel(t);
158
159 switch (event) {
160 case CHR_EVENT_OPENED:
161 /*
162 * 3270 does handshake firstly by the negotiate options in
163 * char-socket.c. Once qemu receives the terminal-type of the
164 * client, mark handshake done and trigger everything rolling again.
165 */
166 t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t);
167 break;
168 case CHR_EVENT_CLOSED:
169 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END;
170 css_conditional_io_interrupt(sch);
171 break;
172 case CHR_EVENT_BREAK:
173 case CHR_EVENT_MUX_IN:
174 case CHR_EVENT_MUX_OUT:
175 /* Ignore */
176 break;
177 }
178 }
179
180 static void terminal_init(EmulatedCcw3270Device *dev, Error **errp)
181 {
182 Terminal3270 *t = TERMINAL_3270(dev);
183 static bool terminal_available;
184
185 if (terminal_available) {
186 error_setg(errp, "Multiple 3270 terminals are not supported.");
187 return;
188 }
189 terminal_available = true;
190 qemu_chr_fe_set_handlers(&t->chr, terminal_can_read,
191 terminal_read, chr_event, NULL, t, NULL, true);
192 }
193
194 static inline CcwDataStream *get_cds(Terminal3270 *t)
195 {
196 return &(CCW_DEVICE(&t->cdev)->sch->cds);
197 }
198
199 static int read_payload_3270(EmulatedCcw3270Device *dev)
200 {
201 Terminal3270 *t = TERMINAL_3270(dev);
202 int len;
203 int ret;
204
205 len = MIN(ccw_dstream_avail(get_cds(t)), t->in_len);
206 ret = ccw_dstream_write_buf(get_cds(t), t->inv, len);
207 if (ret < 0) {
208 return ret;
209 }
210 t->in_len -= len;
211
212 return len;
213 }
214
215 /* TN3270 uses binary transmission, which needs escape IAC to IAC IAC */
216 static int insert_IAC_escape_char(uint8_t *outv, int out_len)
217 {
218 int IAC_num = 0, new_out_len, i, j;
219
220 for (i = 0; i < out_len; i++) {
221 if (outv[i] == IAC) {
222 IAC_num++;
223 }
224 }
225 if (IAC_num == 0) {
226 return out_len;
227 }
228 new_out_len = out_len + IAC_num;
229 for (i = out_len - 1, j = new_out_len - 1; j > i && i >= 0; i--, j--) {
230 outv[j] = outv[i];
231 if (outv[i] == IAC) {
232 outv[--j] = IAC;
233 }
234 }
235 return new_out_len;
236 }
237
238 /*
239 * Write 3270 outbound to socket.
240 * Return the count of 3270 data field if succeeded, zero if failed.
241 */
242 static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd)
243 {
244 Terminal3270 *t = TERMINAL_3270(dev);
245 int retval = 0;
246 int count = ccw_dstream_avail(get_cds(t));
247 int bound = (OUTPUT_BUFFER_SIZE - 3) / 2;
248 int len = MIN(count, bound);
249 int out_len = 0;
250
251 if (!t->handshake_done) {
252 if (!(t->outv[0] == IAC && t->outv[1] != IAC)) {
253 /*
254 * Before having finished 3270 negotiation,
255 * sending outbound data except protocol options is prohibited.
256 */
257 return 0;
258 }
259 }
260 if (!qemu_chr_fe_backend_connected(&t->chr)) {
261 /* We just say we consumed all data if there's no backend. */
262 return count;
263 }
264
265 t->outv[out_len++] = cmd;
266 do {
267 retval = ccw_dstream_read_buf(get_cds(t), &t->outv[out_len], len);
268 if (retval < 0) {
269 return retval;
270 }
271 count = ccw_dstream_avail(get_cds(t));
272 out_len += len;
273
274 out_len = insert_IAC_escape_char(t->outv, out_len);
275 if (!count) {
276 t->outv[out_len++] = IAC;
277 t->outv[out_len++] = IAC_EOR;
278 }
279 retval = qemu_chr_fe_write_all(&t->chr, t->outv, out_len);
280 len = MIN(count, bound);
281 out_len = 0;
282 } while (len && retval >= 0);
283 return (retval <= 0) ? 0 : get_cds(t)->count;
284 }
285
286 static Property terminal_properties[] = {
287 DEFINE_PROP_CHR("chardev", Terminal3270, chr),
288 DEFINE_PROP_END_OF_LIST(),
289 };
290
291 static const VMStateDescription terminal3270_vmstate = {
292 .name = TYPE_TERMINAL_3270,
293 .unmigratable = 1,
294 };
295
296 static void terminal_class_init(ObjectClass *klass, void *data)
297 {
298 DeviceClass *dc = DEVICE_CLASS(klass);
299 EmulatedCcw3270Class *ck = EMULATED_CCW_3270_CLASS(klass);
300
301 device_class_set_props(dc, terminal_properties);
302 dc->vmsd = &terminal3270_vmstate;
303 ck->init = terminal_init;
304 ck->read_payload_3270 = read_payload_3270;
305 ck->write_payload_3270 = write_payload_3270;
306 }
307
308 static const TypeInfo ccw_terminal_info = {
309 .name = TYPE_TERMINAL_3270,
310 .parent = TYPE_EMULATED_CCW_3270,
311 .instance_size = sizeof(Terminal3270),
312 .class_init = terminal_class_init,
313 .class_size = sizeof(EmulatedCcw3270Class),
314 };
315
316 static void register_types(void)
317 {
318 type_register_static(&ccw_terminal_info);
319 }
320
321 type_init(register_types)