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chardev: Basic support for TN3270

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This introduces basic support for TN3270, which needs to negotiate
three Telnet options during handshake:
  - End of Record
  - Binary Transmission
  - Terminal-Type

As a basic implementation, this simply ignores NOP and Interrupt
Process(IP) commands. More work should be done for them later.

For more details, please refer to RFC 854 and 1576.

Signed-off-by: Jing Liu <liujbjl@linux.vnet.ibm.com>
Signed-off-by: Yang Chen <bjcyang@linux.vnet.ibm.com>
Reviewed-by: QingFeng Hao <haoqf@linux.vnet.ibm.com>
Acked-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This commit is contained in:
Jing Liu 2016-09-23 08:06:11 +02:00 • committed by Cornelia Huck
parent e619b14746
commit ae92cbd542
4 changed files with 76 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

76
chardev/char-socket.c
View file

@ -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)
/* 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 */
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;