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