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 int out_len; 34 bool handshake_done; 35 guint timer_tag; 36 } Terminal3270; 37 38 #define TYPE_TERMINAL_3270 "x-terminal3270" 39 #define TERMINAL_3270(obj) \ 40 OBJECT_CHECK(Terminal3270, (obj), TYPE_TERMINAL_3270) 41 42 static int terminal_can_read(void *opaque) 43 { 44 Terminal3270 *t = opaque; 45 46 return INPUT_BUFFER_SIZE - t->in_len; 47 } 48 49 /* 50 * Protocol handshake done, 51 * signal guest by an unsolicited DE irq. 52 */ 53 static void TN3270_handshake_done(Terminal3270 *t) 54 { 55 CcwDevice *ccw_dev = CCW_DEVICE(t); 56 SubchDev *sch = ccw_dev->sch; 57 58 t->handshake_done = true; 59 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END; 60 css_conditional_io_interrupt(sch); 61 } 62 63 /* 64 * Called when the interval is timeout to detect 65 * if the client is still alive by Timing Mark. 66 */ 67 static gboolean send_timing_mark_cb(gpointer opaque) 68 { 69 Terminal3270 *t = opaque; 70 const uint8_t timing[] = {0xff, 0xfd, 0x06}; 71 72 qemu_chr_fe_write_all(&t->chr, timing, sizeof(timing)); 73 return true; 74 } 75 76 /* 77 * Receive inbound data from socket. 78 * For data given to guest, drop the data boundary IAC, IAC_EOR. 79 * TODO: 80 * Using "Reset" key on x3270 may result multiple commands in one packet. 81 * This usually happens when the user meets a poor traffic of the network. 82 * As of now, for such case, we simply terminate the connection, 83 * and we should come back here later with a better solution. 84 */ 85 static void terminal_read(void *opaque, const uint8_t *buf, int size) 86 { 87 Terminal3270 *t = opaque; 88 CcwDevice *ccw_dev = CCW_DEVICE(t); 89 SubchDev *sch = ccw_dev->sch; 90 int end; 91 92 assert(size <= (INPUT_BUFFER_SIZE - t->in_len)); 93 94 if (t->timer_tag) { 95 g_source_remove(t->timer_tag); 96 t->timer_tag = 0; 97 } 98 t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t); 99 100 memcpy(&t->inv[t->in_len], buf, size); 101 t->in_len += size; 102 if (t->in_len < 2) { 103 return; 104 } 105 106 if (!t->handshake_done) { 107 /* 108 * Receiving Terminal Type is the last step of handshake. 109 * The data format: IAC SB Terminal-Type IS <terminal type> IAC SE 110 * The code for Terminal-Type is 0x18, for IS is 0. 111 * Simply check the data format and mark handshake_done. 112 */ 113 if (t->in_len > 6 && t->inv[2] == 0x18 && t->inv[3] == 0x0 && 114 t->inv[t->in_len - 2] == IAC && t->inv[t->in_len - 1] == IAC_SE) { 115 TN3270_handshake_done(t); 116 t->in_len = 0; 117 } 118 return; 119 } 120 121 for (end = 0; end < t->in_len - 1; end++) { 122 if (t->inv[end] == IAC && t->inv[end + 1] == IAC_EOR) { 123 break; 124 } 125 } 126 if (end == t->in_len - 2) { 127 /* Data is valid for consuming. */ 128 t->in_len -= 2; 129 sch->curr_status.scsw.dstat = SCSW_DSTAT_ATTENTION; 130 css_conditional_io_interrupt(sch); 131 } else if (end < t->in_len - 2) { 132 /* "Reset" key is used. */ 133 qemu_chr_fe_disconnect(&t->chr); 134 } else { 135 /* Gathering data. */ 136 return; 137 } 138 } 139 140 static void chr_event(void *opaque, int event) 141 { 142 Terminal3270 *t = opaque; 143 CcwDevice *ccw_dev = CCW_DEVICE(t); 144 SubchDev *sch = ccw_dev->sch; 145 146 /* Ensure the initial status correct, always reset them. */ 147 t->in_len = 0; 148 t->out_len = 0; 149 t->handshake_done = false; 150 if (t->timer_tag) { 151 g_source_remove(t->timer_tag); 152 t->timer_tag = 0; 153 } 154 155 switch (event) { 156 case CHR_EVENT_OPENED: 157 /* 158 * 3270 does handshake firstly by the negotiate options in 159 * char-socket.c. Once qemu receives the terminal-type of the 160 * client, mark handshake done and trigger everything rolling again. 161 */ 162 t->timer_tag = g_timeout_add_seconds(600, send_timing_mark_cb, t); 163 break; 164 case CHR_EVENT_CLOSED: 165 sch->curr_status.scsw.dstat = SCSW_DSTAT_DEVICE_END; 166 css_conditional_io_interrupt(sch); 167 break; 168 } 169 } 170 171 static void terminal_init(EmulatedCcw3270Device *dev, Error **errp) 172 { 173 Terminal3270 *t = TERMINAL_3270(dev); 174 static bool terminal_available; 175 176 if (terminal_available) { 177 error_setg(errp, "Multiple 3270 terminals are not supported."); 178 return; 179 } 180 terminal_available = true; 181 qemu_chr_fe_set_handlers(&t->chr, terminal_can_read, 182 terminal_read, chr_event, t, NULL, true); 183 } 184 185 static int read_payload_3270(EmulatedCcw3270Device *dev, uint32_t cda, 186 uint16_t count) 187 { 188 Terminal3270 *t = TERMINAL_3270(dev); 189 int len; 190 191 len = MIN(count, t->in_len); 192 cpu_physical_memory_write(cda, t->inv, len); 193 t->in_len -= len; 194 195 return len; 196 } 197 198 /* TN3270 uses binary transmission, which needs escape IAC to IAC IAC */ 199 static int insert_IAC_escape_char(uint8_t *outv, int out_len) 200 { 201 int IAC_num = 0, new_out_len, i, j; 202 203 for (i = 0; i < out_len; i++) { 204 if (outv[i] == IAC) { 205 IAC_num++; 206 } 207 } 208 if (IAC_num == 0) { 209 return out_len; 210 } 211 new_out_len = out_len + IAC_num; 212 for (i = out_len - 1, j = new_out_len - 1; j > i && i >= 0; i--, j--) { 213 outv[j] = outv[i]; 214 if (outv[i] == IAC) { 215 outv[--j] = IAC; 216 } 217 } 218 return new_out_len; 219 } 220 221 /* 222 * Write 3270 outbound to socket. 223 * Return the count of 3270 data field if succeeded, zero if failed. 224 */ 225 static int write_payload_3270(EmulatedCcw3270Device *dev, uint8_t cmd, 226 uint32_t cda, uint16_t count) 227 { 228 Terminal3270 *t = TERMINAL_3270(dev); 229 int retval = 0; 230 231 assert(count <= (OUTPUT_BUFFER_SIZE - 3) / 2); 232 233 if (!t->handshake_done) { 234 if (!(t->outv[0] == IAC && t->outv[1] != IAC)) { 235 /* 236 * Before having finished 3270 negotiation, 237 * sending outbound data except protocol options is prohibited. 238 */ 239 return 0; 240 } 241 } 242 if (!qemu_chr_fe_get_driver(&t->chr)) { 243 /* We just say we consumed all data if there's no backend. */ 244 return count; 245 } 246 t->outv[0] = cmd; 247 cpu_physical_memory_read(cda, &t->outv[1], count); 248 t->out_len = count + 1; 249 250 t->out_len = insert_IAC_escape_char(t->outv, t->out_len); 251 t->outv[t->out_len++] = IAC; 252 t->outv[t->out_len++] = IAC_EOR; 253 254 retval = qemu_chr_fe_write_all(&t->chr, t->outv, t->out_len); 255 return (retval <= 0) ? 0 : (retval - 3); 256 } 257 258 static Property terminal_properties[] = { 259 DEFINE_PROP_CHR("chardev", Terminal3270, chr), 260 DEFINE_PROP_END_OF_LIST(), 261 }; 262 263 static const VMStateDescription terminal3270_vmstate = { 264 .name = TYPE_TERMINAL_3270, 265 .unmigratable = 1, 266 }; 267 268 static void terminal_class_init(ObjectClass *klass, void *data) 269 { 270 DeviceClass *dc = DEVICE_CLASS(klass); 271 EmulatedCcw3270Class *ck = EMULATED_CCW_3270_CLASS(klass); 272 273 dc->props = terminal_properties; 274 dc->vmsd = &terminal3270_vmstate; 275 ck->init = terminal_init; 276 ck->read_payload_3270 = read_payload_3270; 277 ck->write_payload_3270 = write_payload_3270; 278 } 279 280 static const TypeInfo ccw_terminal_info = { 281 .name = TYPE_TERMINAL_3270, 282 .parent = TYPE_EMULATED_CCW_3270, 283 .instance_size = sizeof(Terminal3270), 284 .class_init = terminal_class_init, 285 .class_size = sizeof(EmulatedCcw3270Class), 286 }; 287 288 static void register_types(void) 289 { 290 type_register_static(&ccw_terminal_info); 291 } 292 293 type_init(register_types) 294