chardev: Basic support for TN3270 (ae92cbd5) · Commits · SUMMER2020 / students / proj-2021291

chardev/char-socket.c

+56 −20

Original line number	Diff line number	Diff line
		@@ -55,6 +55,7 @@ typedef struct {
		SocketAddress *addr;
		bool is_listen;
		bool is_telnet;
		bool is_tn3270;

		guint reconnect_timer;
		int64_t reconnect_time;
		@@ -141,19 +142,25 @@ static int tcp_chr_read_poll(void *opaque)
		return s->max_size;
		}

		#define IAC 255
		#define IAC_BREAK 243
		static void tcp_chr_process_IAC_bytes(Chardev *chr,
		SocketChardev *s,
		uint8_t buf, int size)
		{
		/* Handle any telnet client's basic IAC options to satisfy char by
		* char mode with no echo. All IAC options will be removed from
		* the buf and the do_telnetopt variable will be used to track the
		* state of the width of the IAC information.
		/* Handle any telnet or tn3270 client's basic IAC options.
		* For telnet options, it satisfies char by char mode with no echo.
		* For tn3270 options, it satisfies binary mode with EOR.
		* All IAC options will be removed from the buf and the do_opt
		* pointer will be used to track the state of the width of the
		* IAC information.
		*
		* IAC commands come in sets of 3 bytes with the exception of the
		* "IAC BREAK" command and the double IAC.
		* RFC854: "All TELNET commands consist of at least a two byte sequence.
		* The commands dealing with option negotiation are three byte sequences,
		* the third byte being the code for the option referenced."
		* "IAC BREAK", "IAC IP", "IAC NOP" and the double IAC are two bytes.
		* "IAC SB", "IAC SE" and "IAC EOR" are saved to split up data boundary
		* for tn3270.
		* NOP, Break and Interrupt Process(IP) might be encountered during a TN3270
		* session, and NOP and IP need to be done later.
		*/

		int i;
		@@ -174,6 +181,18 @@ static void tcp_chr_process_IAC_bytes(Chardev *chr,
		/* Handle IAC break commands by sending a serial break */
		qemu_chr_be_event(chr, CHR_EVENT_BREAK);
		s->do_telnetopt++;
		} else if (s->is_tn3270 && ((unsigned char)buf[i] == IAC_EOR
		\|\| (unsigned char)buf[i] == IAC_SB
		\|\| (unsigned char)buf[i] == IAC_SE)
		&& s->do_telnetopt == 2) {
		buf[j++] = IAC;
		buf[j++] = buf[i];
		s->do_telnetopt++;
		} else if (s->is_tn3270 && ((unsigned char)buf[i] == IAC_IP
		\|\| (unsigned char)buf[i] == IAC_NOP)
		&& s->do_telnetopt == 2) {
		/* TODO: IP and NOP need to be implemented later. */
		s->do_telnetopt++;
		}
		s->do_telnetopt++;
		}
		@@ -512,7 +531,7 @@ static void tcp_chr_update_read_handler(Chardev *chr,

		typedef struct {
		Chardev *chr;
		char buf[12];
		char buf[21];
		size_t buflen;
		} TCPChardevTelnetInit;

		@@ -550,9 +569,6 @@ static void tcp_chr_telnet_init(Chardev *chr)
		TCPChardevTelnetInit *init = g_new0(TCPChardevTelnetInit, 1);
		size_t n = 0;

		init->chr = chr;
		init->buflen = 12;

		#define IACSET(x, a, b, c) \
		do { \
		x[n++] = a; \
		@@ -560,12 +576,26 @@ static void tcp_chr_telnet_init(Chardev *chr)
		x[n++] = c; \
		} while (0)

		init->chr = chr;
		if (!s->is_tn3270) {
		init->buflen = 12;
		/* Prep the telnet negotion to put telnet in binary,
		* no echo, single char mode */
		IACSET(init->buf, 0xff, 0xfb, 0x01); /* IAC WILL ECHO */
		IACSET(init->buf, 0xff, 0xfb, 0x03); /* IAC WILL Suppress go ahead */
		IACSET(init->buf, 0xff, 0xfb, 0x00); /* IAC WILL Binary */
		IACSET(init->buf, 0xff, 0xfd, 0x00); /* IAC DO Binary */
		} else {
		init->buflen = 21;
		/* Prep the TN3270 negotion based on RFC1576 */
		IACSET(init->buf, 0xff, 0xfd, 0x19); /* IAC DO EOR */
		IACSET(init->buf, 0xff, 0xfb, 0x19); /* IAC WILL EOR */
		IACSET(init->buf, 0xff, 0xfd, 0x00); /* IAC DO BINARY */
		IACSET(init->buf, 0xff, 0xfb, 0x00); /* IAC WILL BINARY */
		IACSET(init->buf, 0xff, 0xfd, 0x18); /* IAC DO TERMINAL TYPE */
		IACSET(init->buf, 0xff, 0xfa, 0x18); /* IAC SB TERMINAL TYPE */
		IACSET(init->buf, 0x01, 0xff, 0xf0); /* SEND IAC SE */
		}

		#undef IACSET

		@@ -585,7 +615,8 @@ static void tcp_chr_tls_handshake(QIOTask *task,
		if (qio_task_propagate_error(task, NULL)) {
		tcp_chr_disconnect(chr);
		} else {
		if (s->do_telnetopt) {
		/* tn3270 does not support TLS yet */
		if (s->do_telnetopt && !s->is_tn3270) {
		tcp_chr_telnet_init(chr);
		} else {
		tcp_chr_connect(chr);
		@@ -824,12 +855,14 @@ static void qmp_chardev_open_socket(Chardev *chr,
		bool do_nodelay = sock->has_nodelay ? sock->nodelay : false;
		bool is_listen = sock->has_server ? sock->server : true;
		bool is_telnet = sock->has_telnet ? sock->telnet : false;
		bool is_tn3270 = sock->has_tn3270 ? sock->tn3270 : false;
		bool is_waitconnect = sock->has_wait ? sock->wait : false;
		int64_t reconnect = sock->has_reconnect ? sock->reconnect : 0;
		QIOChannelSocket *sioc = NULL;

		s->is_listen = is_listen;
		s->is_telnet = is_telnet;
		s->is_tn3270 = is_tn3270;
		s->do_nodelay = do_nodelay;
		if (sock->tls_creds) {
		Object *creds;
		@@ -879,7 +912,7 @@ static void qmp_chardev_open_socket(Chardev *chr,
		addr, is_listen, is_telnet);

		if (is_listen) {
		if (is_telnet) {
		if (is_telnet \|\| is_tn3270) {
		s->do_telnetopt = 1;
		}
		} else if (reconnect > 0) {
		@@ -933,6 +966,7 @@ static void qemu_chr_parse_socket(QemuOpts opts, ChardevBackend backend,
		bool is_listen = qemu_opt_get_bool(opts, "server", false);
		bool is_waitconnect = is_listen && qemu_opt_get_bool(opts, "wait", true);
		bool is_telnet = qemu_opt_get_bool(opts, "telnet", false);
		bool is_tn3270 = qemu_opt_get_bool(opts, "tn3270", false);
		bool do_nodelay = !qemu_opt_get_bool(opts, "delay", true);
		int64_t reconnect = qemu_opt_get_number(opts, "reconnect", 0);
		const char *path = qemu_opt_get(opts, "path");
		@@ -968,6 +1002,8 @@ static void qemu_chr_parse_socket(QemuOpts opts, ChardevBackend backend,
		sock->server = is_listen;
		sock->has_telnet = true;
		sock->telnet = is_telnet;
		sock->has_tn3270 = true;
		sock->tn3270 = is_tn3270;
		sock->has_wait = true;
		sock->wait = is_waitconnect;
		sock->has_reconnect = true;

chardev/char.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -696,7 +696,8 @@ QemuOpts qemu_chr_parse_compat(const char label, const char *filename)
		return opts;
		}
		if (strstart(filename, "tcp:", &p) \|\|
		strstart(filename, "telnet:", &p)) {
		strstart(filename, "telnet:", &p) \|\|
		strstart(filename, "tn3270:", &p)) {
		if (sscanf(p, "%64[^:]:%32[^,]%n", host, port, &pos) < 2) {
		host[0] = 0;
		if (sscanf(p, ":%32[^,]%n", port, &pos) < 1)
		@@ -712,8 +713,11 @@ QemuOpts qemu_chr_parse_compat(const char label, const char *filename)
		goto fail;
		}
		}
		if (strstart(filename, "telnet:", &p))
		if (strstart(filename, "telnet:", &p)) {
		qemu_opt_set(opts, "telnet", "on", &error_abort);
		} else if (strstart(filename, "tn3270:", &p)) {
		qemu_opt_set(opts, "tn3270", "on", &error_abort);
		}
		return opts;
		}
		if (strstart(filename, "udp:", &p)) {
		@@ -1176,6 +1180,9 @@ QemuOptsList qemu_chardev_opts = {
		},{
		.name = "telnet",
		.type = QEMU_OPT_BOOL,
		},{
		.name = "tn3270",
		.type = QEMU_OPT_BOOL,
		},{
		.name = "tls-creds",
		.type = QEMU_OPT_STRING,

include/sysemu/char.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,14 @@
		#include "qemu/bitmap.h"
		#include "qom/object.h"

		#define IAC_EOR 239
		#define IAC_SE 240
		#define IAC_NOP 241
		#define IAC_BREAK 243
		#define IAC_IP 244
		#define IAC_SB 250
		#define IAC 255

		/* character device */

		typedef enum {

qapi-schema.json

+3 −0

Original line number	Diff line number	Diff line
		@@ -4877,6 +4877,8 @@
		# @nodelay: set TCP_NODELAY socket option (default: false)
		# @telnet: enable telnet protocol on server
		# sockets (default: false)
		# @tn3270: enable tn3270 protocol on server
		# sockets (default: false) (Since: 2.10)
		# @reconnect: For a client socket, if a socket is disconnected,
		# then attempt a reconnect after the given number of seconds.
		# Setting this to zero disables this function. (default: 0)
		@@ -4890,6 +4892,7 @@
		'*wait' : 'bool',
		'*nodelay' : 'bool',
		'*telnet' : 'bool',
		'*tn3270' : 'bool',
		'*reconnect' : 'int' },
		'base': 'ChardevCommon' }