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