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