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 "chardev/char-fe.h" 17 #include "hw/s390x/3270-ccw.h" 18 19 /* Enough spaces for different window sizes. */ 20 #define INPUT_BUFFER_SIZE 1000 21 /* 22 * 1 for header, 1024*2 for datastream, 2 for tail 23 * Reserve enough spaces for telnet IAC escape. 24 */ 25 #define OUTPUT_BUFFER_SIZE 2051 26 27 typedef struct Terminal3270 { 28 EmulatedCcw3270Device cdev; 29 CharBackend chr; 30 uint8_t inv[INPUT_BUFFER_SIZE]; 31 uint8_t outv[OUTPUT_BUFFER_SIZE]; 32 int in_len; 33 bool handshake_done; 34 GSource *timer_src; 35 } Terminal3270; 36 37 #define TYPE_TERMINAL_3270 "x-terminal3270" 38 #define TERMINAL_3270(obj) \ 39 OBJECT_CHECK(Terminal3270, (obj), TYPE_TERMINAL_3270) 40 41 static int terminal_can_read(void *opaque) 42 { 43 Terminal3270 *t = opaque; 44 45 return INPUT_BUFFER_SIZE - t->in_len; 46 } 47 48 static void terminal_timer_cancel(Terminal3270 *t) 49 { 50 if (t->timer_src) { 51 g_source_destroy(t->timer_src); 52 g_source_unref(t->timer_src); 53 t->timer_src = NULL; 54 } 55 } 56 57 /* 58 * Protocol handshake done, 59 * signal guest by an unsolicited DE irq. 60 */ 61 static void TN3270_handshake_done(Terminal3270 *t) 62 { 63 CcwDevice *ccw_dev = CCW_DEVICE(t); 64 SubchDev *sch = ccw_dev->sch; 65 66 t->handshake_done = true; 67 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END; 68 css_conditional_io_interrupt(sch); 69 } 70 71 /* 72 * Called when the interval is timeout to detect 73 * if the client is still alive by Timing Mark. 74 */ 75 static gboolean send_timing_mark_cb(gpointer opaque) 76 { 77 Terminal3270 *t = opaque; 78 const uint8_t timing[] = {0xff, 0xfd, 0x06}; 79 80 qemu_chr_fe_write_all(&t->chr, timing, sizeof(timing)); 81 return true; 82 } 83 84 /* 85 * Receive inbound data from socket. 86 * For data given to guest, drop the data boundary IAC, IAC_EOR. 87 * TODO: 88 * Using "Reset" key on x3270 may result multiple commands in one packet. 89 * This usually happens when the user meets a poor traffic of the network. 90 * As of now, for such case, we simply terminate the connection, 91 * and we should come back here later with a better solution. 92 */ 93 static void terminal_read(void *opaque, const uint8_t *buf, int size) 94 { 95 Terminal3270 *t = opaque; 96 CcwDevice *ccw_dev = CCW_DEVICE(t); 97 SubchDev *sch = ccw_dev->sch; 98 int end; 99 100 assert(size <= (INPUT_BUFFER_SIZE - t->in_len)); 101 102 terminal_timer_cancel(t); 103 t->timer_src = qemu_chr_timeout_add_ms(t->chr.chr, 600 * 1000, 104 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_src = qemu_chr_timeout_add_ms(t->chr.chr, 600 * 1000, 164 send_timing_mark_cb, t); 165 break; 166 case CHR_EVENT_CLOSED: 167 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END; 168 css_conditional_io_interrupt(sch); 169 break; 170 } 171 } 172 173 static void terminal_init(EmulatedCcw3270Device *dev, Error **errp) 174 { 175 Terminal3270 *t = TERMINAL_3270(dev); 176 static bool terminal_available; 177 178 if (terminal_available) { 179 error_setg(errp, "Multiple 3270 terminals are not supported."); 180 return; 181 } 182 terminal_available = true; 183 qemu_chr_fe_set_handlers(&t->chr, terminal_can_read, 184 terminal_read, chr_event, NULL, t, NULL, true); 185 } 186 187 static inline CcwDataStream *get_cds(Terminal3270 *t) 188 { 189 return &(CCW_DEVICE(&t->cdev)->sch->cds); 190 } 191 192 static int read_payload_3270(EmulatedCcw3270Device *dev) 193 { 194 Terminal3270 *t = TERMINAL_3270(dev); 195 int len; 196 197 len = MIN(ccw_dstream_avail(get_cds(t)), t->in_len); 198 ccw_dstream_write_buf(get_cds(t), t->inv, len); 199 t->in_len -= len; 200 201 return len; 202 } 203 204 /* TN3270 uses binary transmission, which needs escape IAC to IAC IAC */ 205 static int insert_IAC_escape_char(uint8_t *outv, int out_len) 206 { 207 int IAC_num = 0, new_out_len, i, j; 208 209 for (i = 0; i < out_len; i++) { 210 if (outv[i] == IAC) { 211 IAC_num++; 212 } 213 } 214 if (IAC_num == 0) { 215 return out_len; 216 } 217 new_out_len = out_len + IAC_num; 218 for (i = out_len - 1, j = new_out_len - 1; j > i && i >= 0; i--, j--) { 219 outv[j] = outv[i]; 220 if (outv[i] == IAC) { 221 outv[--j] = IAC; 222 } 223 } 224 return new_out_len; 225 } 226 227 /* 228 * Write 3270 outbound to socket. 229 * Return the count of 3270 data field if succeeded, zero if failed. 230 */ 231 static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd) 232 { 233 Terminal3270 *t = TERMINAL_3270(dev); 234 int retval = 0; 235 int count = ccw_dstream_avail(get_cds(t)); 236 int bound = (OUTPUT_BUFFER_SIZE - 3) / 2; 237 int len = MIN(count, bound); 238 int out_len = 0; 239 240 if (!t->handshake_done) { 241 if (!(t->outv[0] == IAC && t->outv[1] != IAC)) { 242 /* 243 * Before having finished 3270 negotiation, 244 * sending outbound data except protocol options is prohibited. 245 */ 246 return 0; 247 } 248 } 249 if (!qemu_chr_fe_backend_connected(&t->chr)) { 250 /* We just say we consumed all data if there's no backend. */ 251 return count; 252 } 253 254 t->outv[out_len++] = cmd; 255 do { 256 ccw_dstream_read_buf(get_cds(t), &t->outv[out_len], len); 257 count = ccw_dstream_avail(get_cds(t)); 258 out_len += len; 259 260 out_len = insert_IAC_escape_char(t->outv, out_len); 261 if (!count) { 262 t->outv[out_len++] = IAC; 263 t->outv[out_len++] = IAC_EOR; 264 } 265 retval = qemu_chr_fe_write_all(&t->chr, t->outv, out_len); 266 len = MIN(count, bound); 267 out_len = 0; 268 } while (len && retval >= 0); 269 return (retval <= 0) ? 0 : get_cds(t)->count; 270 } 271 272 static Property terminal_properties[] = { 273 DEFINE_PROP_CHR("chardev", Terminal3270, chr), 274 DEFINE_PROP_END_OF_LIST(), 275 }; 276 277 static const VMStateDescription terminal3270_vmstate = { 278 .name = TYPE_TERMINAL_3270, 279 .unmigratable = 1, 280 }; 281 282 static void terminal_class_init(ObjectClass *klass, void *data) 283 { 284 DeviceClass *dc = DEVICE_CLASS(klass); 285 EmulatedCcw3270Class *ck = EMULATED_CCW_3270_CLASS(klass); 286 287 dc->props = terminal_properties; 288 dc->vmsd = &terminal3270_vmstate; 289 ck->init = terminal_init; 290 ck->read_payload_3270 = read_payload_3270; 291 ck->write_payload_3270 = write_payload_3270; 292 } 293 294 static const TypeInfo ccw_terminal_info = { 295 .name = TYPE_TERMINAL_3270, 296 .parent = TYPE_EMULATED_CCW_3270, 297 .instance_size = sizeof(Terminal3270), 298 .class_init = terminal_class_init, 299 .class_size = sizeof(EmulatedCcw3270Class), 300 }; 301 302 static void register_types(void) 303 { 304 type_register_static(&ccw_terminal_info); 305 } 306 307 type_init(register_types) 308