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rfc2217
picocom/tn2217.c
Nick Patavalis 1c8e238022 Debugging tweaks
2018-03-03 08:39:55 +02:00

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/* vi: set sw=4 ts=4:
*
* tn2217.c
*
* TELNET and COM-PORT (RFC2217) remote terminal protocol.
*
* Provides a network virtual terminal over a TELNET TCP connection.
* Uses the TELNET COM PORT (RFC2217) option which provides control
* over baud rate, parity, data bits and modem control lines at a com
* port server.
*
* See also:
* https://tools.ietf.org/html/rfc854 (TELNET protocol)
* https://tools.ietf.org/html/rfc856 (BINARY option)
* https://tools.ietf.org/html/rfc857 (ECHO option)
* https://tools.ietf.org/html/rfc858 (SGA option)
* https://tools.ietf.org/html/rfc2217 (COMPORT option)
* https://tools.ietf.org/html/rfc1143 (Q method for option negotiation)
*
* https://sourceforge.net/projects/sredird/ (sredird RFC2217 server)
* http://www.columbia.edu/kermit/ftp/ (sredird from old Kermit project)
* https://sourceforge.net/projects/ser2net/ (another RFC2217 server)
*
* by David Leonard (https://github.com/dleonard0)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netdb.h>
#include <errno.h>
#include "fdio.h"
#include "termint.h"
#include "tncomport.h"
#include "tn2217.h"
#include <arpa/telnet.h>
#if 1
/* Disable debugging code altogether */
#define DEBUG 0
#define DB(fl, ...) /* nothing */
#define DBG(...) /* nothing */
#define DB_ON(fl) 0
#else
/* Enable debugging code */
#define DEBUG 1
#define DB(fl, ...) \
do { \
if ( DB_MASK & (fl) ) \
fd_printf(STDERR_FILENO, __VA_ARGS__); \
} while (0)
#define DBG(...) DB(DB_OTH, __VA_ARGS__)
#define DB_ON(fl) (DB_MASK & (fl))
/* Debugging message groups */
#define DB_OTH (1 << 0) /* other */
#define DB_NEG (1 << 1) /* option negotiation messages */
#define DB_OPT (1 << 2) /* option values */
#define DB_CMP (1 << 3) /* comport messages */
/* Enable specific groups */
#define DB_MASK (DB_OTH | DB_NEG /* | DB_OPT */ | DB_CMP)
#endif
/* Important info / warnings / errors to stderr */
#define pinfof(...) fd_printf(STDERR_FILENO, __VA_ARGS__)
/* We'll ask the remote end to use this modem state mask */
#define MODEMSTATE_MASK (COMPORT_MODEM_CD | \
COMPORT_MODEM_RI | \
COMPORT_MODEM_DSR | \
COMPORT_MODEM_CTS )
/* RFC1143 Q method for TELNET option tracking. Thanks, djb!
*
* TELNET options are enabled independently at each side, and the Q method
* is a robust way to track peer/local option state without entering loops.
* The initial states are NO (disabled) for all options at each sides.
*
* tn2217_do(), tn2217_dont(), tn2217_will(), tn2217_wont()
* - Called to drive the Q state towards the wanted direction.
* - These functions directly writes messages to the telnet socket
*
* tn2217_recv_opt()
* - Called on receipt of DO/DONT/WILL/WONT, and update the Q state
* and reply with an answer on the telnet socket.
* - Calls tn2217_remote_should(), tn2217_local_should() to
* know how to answer options not explicity driven by tn2217_do() etc.
* - When an opt becomes stable, calls tn2217_check_options_changed().
*/
struct q_option {
unsigned int us : 2,
him: 2,
# define NO 0 /* Agreed disable */
# define YES 1 /* Agreed enable */
# define WANTYES 2 /* We sent WILL or DO */
# define WANTNO 3 /* We sent WONT or DONT */
usq : 1,
himq : 1;
# define EMPTY 0 /* queue is empty */
# define OPPOSITE 1 /* queue contains an opposition */
};
/* TELNET protocol state. */
struct tn2217_state {
struct q_option opt[256]; /* Negotiated TELNET options */
struct termios termios; /* Predicted remote com port geometry */
int modem; /* Predicted remote com port signals */
unsigned char cmdbuf[32]; /* IAC command accumulator */
unsigned char cmdbuflen;
unsigned int cmdiac : 1; /* 1 iff last cmdbuf ch is incomplete IAC */
int conf_pending; /* # of not-replied config commands */
/* When COM-PORT option is fully negotiated, can_comport
* is set to true. This also means that any deferred termios/modem
* settings will be triggered. */
unsigned int can_comport : 1, /* WILL COMPORT was received */
set_termios : 1, /* tcsetattr called before can_comport */
set_modem : 1, /* modem_bis/c called before can_comport */
configed: 1; /* INITIAL config complete */
};
static int remote_should(struct term_s *t, unsigned char opt);
static int local_should(struct term_s *t, unsigned char opt);
static int escape_write(struct term_s *t, const void *buf, unsigned bufsz);
static int read_and_proc(struct term_s *t, void *buf, unsigned bufsz);
static int comport_recv_cmd(struct term_s *t, unsigned char cmd,
unsigned char *data, unsigned int datalen);
static int comport_start(struct term_s *t);
/* Access the private state structure of the terminal */
static struct tn2217_state *
tn2217_state(struct term_s *t)
{
return (struct tn2217_state *)t->priv;
}
#define STATE(t) tn2217_state(t)
#if DEBUG
/* Some debug helpers (do not use in non-debugging code, they will go
away) */
static const char *
str_nn(unsigned char i)
{
static const char *names[256];
if ( ! names[i] ) {
char *v;
v = malloc(4);
snprintf(v, 4, "%d", i);
names[i] = v;
}
return names[i];
}
static const char *
str_cmd(unsigned char cmd) {
static const char *names[] = {
"WILL", "WONT", "DO", "DONT"
};
return ( (cmd < WILL || cmd > DONT)
? str_nn(cmd) : names[cmd - WILL] );
}
static const char *
str_opt(unsigned char opt) {
static const char *names[] = {
[TELOPT_BINARY] = "BINARY",
[TELOPT_ECHO] = "ECHO",
[TELOPT_SGA] = "SGA",
[TELOPT_COMPORT] = "COMPORT",
[255] = NULL
};
return names[opt] ? names[opt] : str_nn(opt);
}
static const char *
str_optval(int val) {
static const char *names[] = {
"NO", "YES", "WANTYES", "WANTNO"
};
return names[(unsigned)val&3];
}
/* Return simple debug representation of a termios,
eg "19200:8:none:1:RTS/CTS" */
const char *
repr_termios(const struct termios *tio)
{
static char out[256];
snprintf(out, sizeof out,
"%u:%u:%s:%u:%s",
tios_get_baudrate(tio, NULL),
tios_get_databits(tio),
parity_str[tios_get_parity(tio)],
tios_get_stopbits(tio),
flow_str[tios_get_flowcntrl(tio)]);
return out;
}
/* Return simple debug representation of a modem bits, eg "<dtr,cd>" */
const char *
repr_modem(int m)
{
static char out[256];
snprintf(out, sizeof out,
"<%s%s%s%s%s%s>",
(m & MCTL_DTR) ? ",dtr":"",
(m & MCTL_DSR) ? ",dsr":"",
(m & MCTL_DCD) ? ",dcd":"",
(m & MCTL_RTS) ? ",rts":"",
(m & MCTL_CTS) ? ",cts":"",
(m & MCTL_RI) ? ",ri":"");
if (out[1] == ',') {
out[1] = '<';
return &out[1];
} else
return "<>";
}
#endif /* of DEBUG */
/* Called when a TELNET option changes */
static int
check_options_changed(struct term_s *t, unsigned char opt)
{
struct tn2217_state *s = STATE(t);
int rval = 0;
DB(DB_OPT, "[opt %s %s %s]\r\n", str_opt(opt),
str_optval(s->opt[opt].us), str_optval(s->opt[opt].him));
/* Detect the first time that the COM-PORT option becomes acceptable. */
if ( !s->can_comport &&
s->opt[TELOPT_COMPORT].us == YES )
{
s->can_comport = 1;
rval = comport_start(t);
}
return rval;
}
/* Starts protocol to enable/disable a peer option (sends DO/DONT). */
static int
remote_opt(struct term_s *t, unsigned char opt, int want)
{
struct tn2217_state *s = STATE(t);
struct q_option *q = &s->opt[opt];
unsigned char msg[3] = { IAC, 0, opt };
if (q->him == want ? NO : YES) {
msg[1] = want ? DO : DONT;
if ( writen_ni(t->fd, msg, sizeof msg) != sizeof msg ) {
term_errno = TERM_EOUTPUT; return -1;
}
DB(DB_NEG, "[sent: %s %s]\r\n", str_cmd(msg[1]), str_opt(opt));
q->him = want ? WANTYES : WANTNO;
} else if (q->him == WANTNO) {
q->himq = want ? OPPOSITE : EMPTY;
} else if (q->him == WANTYES) {
q->himq = want ? EMPTY : OPPOSITE;
}
return check_options_changed(t, opt);
}
/* Starts protocol to enable/disable a local option (sends WILL/WONT). */
static int
local_opt(struct term_s *t, unsigned char opt, int want)
{
struct tn2217_state *s = STATE(t);
struct q_option *q = &s->opt[opt];
unsigned char msg[3] = { IAC, 0, opt };
if (q->us == want ? NO : YES) {
msg[1] = want ? WILL : WONT;
if ( writen_ni(t->fd, msg, sizeof msg) != sizeof msg ) {
term_errno = TERM_EOUTPUT; return -1;
}
DB(DB_NEG, "[sent: %s %s]\r\n", str_cmd(msg[1]), str_opt(opt));
q->us = want ? WANTYES : WANTNO;
} else if (q->us == WANTNO) {
q->usq = want ? OPPOSITE : EMPTY;
} else if (q->us == WANTYES) {
q->usq = want ? EMPTY : OPPOSITE;
}
return check_options_changed(t, opt);
}
#define opt_do(t, opt) remote_opt(t, opt, 1)
#define opt_dont(t, opt) remote_opt(t, opt, 0)
#define opt_will(t, opt) local_opt(t, opt, 1)
#define opt_wont(t, opt) local_opt(t, opt, 0)
/* Receive a WILL/WONT/DO/DONT message, and update our local state. */
static int
recv_opt(struct term_s *t, unsigned char op, unsigned char opt)
{
struct tn2217_state *s = STATE(t);
struct q_option *q = &s->opt[opt];
unsigned char respond = 0;
DB(DB_NEG, "[received: %s %s]\r\n", str_cmd(op), str_opt(opt));
/* See RFC1143 for detailed explanation of the following logic.
* It is a transliteration & compacting of the RFC's algorithm. */
switch (op) {
case WILL:
if (q->him == NO) {
if (remote_should(t, opt)) {
q->him = YES;
respond = DO;
} else {
respond = DONT;
}
} else if (q->him == WANTNO) {
q->him = (q->himq == EMPTY) ? NO : YES;
q->himq = EMPTY;
} else if (q->him == WANTYES) {
if (q->himq == EMPTY)
q->him = YES;
else {
q->him = WANTNO;
q->himq = EMPTY;
respond = DONT;
}
}
break;
case WONT:
if (q->him == YES) {
q->him = NO;
respond = DONT;
} else if (q->him == WANTNO) {
if (q->himq == EMPTY)
q->him = NO;
else {
q->him = WANTYES;
q->himq = EMPTY;
respond = DO;
}
} else if (q->him == WANTYES) {
q->him = NO;
q->himq = EMPTY;
}
break;
case DO:
if (q->us == NO) {
if (local_should(t, opt)) {
q->us = YES;
respond = WILL;
} else {
respond = WONT;
}
} else if (q->us == WANTNO) {
q->us = (q->usq == EMPTY) ? NO : YES;
q->usq = EMPTY;
} else if (q->us == WANTYES) {
if (q->usq == EMPTY)
q->us = YES;
else {
q->us = WANTNO;
q->usq = EMPTY;
respond = WONT;
}
}
break;
case DONT:
if (q->us == YES) {
q->us = NO;
respond = WONT;
} else if (q->us == WANTNO) {
if (q->usq == EMPTY)
q->us = NO;
else {
q->us = WANTYES;
q->usq = EMPTY;
respond = WILL;
}
} else if (q->us == WANTYES) {
q->us = NO;
q->usq = EMPTY;
}
break;
}
if (respond) {
unsigned char msg[3] = { IAC, respond, opt };
if ( writen_ni(t->fd, msg, sizeof msg) != sizeof msg) {
term_errno = TERM_EOUTPUT; return -1;
}
DB(DB_NEG, "[sent: %s %s]\r\n", str_cmd(respond), str_opt(opt));
}
return check_options_changed(t, opt);
}
/* Receive and process a single byte of an IAC command.
* The caller will have appended the byte to s->cmdbuf[] already.
* Completion of a command is signaled by setting s->cmdbuflen to 0. */
static int
recv_cmd_partial(struct term_s *t)
{
struct tn2217_state *s = STATE(t);
unsigned char *cmd = s->cmdbuf;
unsigned int cmdlen = s->cmdbuflen;
int rval = 0;
/* assert(cmdlen > 1) */
/* Note: Normal completion is indicated with 'break'.
* For incomplete commands, return with 'goto incomplete'. */
switch (cmd[1]) {
case WILL: case WONT: case DO: case DONT:
if (cmdlen < 3) /* {IAC [DO|...] opt} */
goto incomplete;
rval = recv_opt(t, cmd[1], cmd[2]);
break;
case SB: /* {IAC SB ... IAC SE} */
if (cmdlen < 3) {
s->cmdiac = 0;
goto incomplete;
}
if (!s->cmdiac && cmd[cmdlen -1] == IAC) {
s->cmdiac = 1;
s->cmdbuflen--;
goto incomplete;
}
if (!s->cmdiac)
goto incomplete;
s->cmdiac = 0;
if (cmd[cmdlen - 1] == IAC)
goto incomplete; /* IAC left at end of cmd[] */
if (cmd[--cmdlen] != SE) { /* remove trailing SE */
pinfof("[BAD TELNET SB]\r\n");
break;
}
if (cmdlen >= 4 && cmd[2] == TELOPT_COMPORT)
rval = comport_recv_cmd(t, cmd[3], cmd + 4, cmdlen - 4);
break;
case AYT:
pinfof("[REMOTE AYT]\r\n");
/* writen_ni(t->fd, "\377\361", 2); */ /* respond with NOP? */
break;
case BREAK:
pinfof("[REMOTE BREAK]\r\n");
break;
case IP:
pinfof("[REMOTE INTERRUPT]\r\n");
break;
default:
/* Ignore everything else */
break;
}
s->cmdbuflen = 0;
return rval < 0 ? rval : 1;
incomplete:
return rval < 0 ? rval : 0;
}
/* Should the remote enable its option if it tells us it WILL/WONT? */
static int
remote_should(struct term_s *t, unsigned char opt)
{
return opt == TELOPT_BINARY ||
opt == TELOPT_ECHO ||
opt == TELOPT_SGA;
}
/* Should we enable a local option if remote asks us to DO/DONT? */
static int
local_should(struct term_s *t, unsigned char opt)
{
return opt == TELOPT_BINARY ||
opt == TELOPT_SGA ||
opt == TELOPT_COMPORT;
}
/* Opens a TCP socket to a host. Returns -1 on failure. */
int
tn2217_open(const char *port)
{
struct addrinfo *ais = NULL;
struct addrinfo *ai;
struct addrinfo hints;
char *node;
const char *service = "telnet";
int error;
char *sep = NULL;
int fd = -1;
long fl;
/* Allow a port number to be specified with a comma */
node = strdup(port);
sep = strrchr(node, ',');
if ( sep ) {
*sep++ = '\0';
service = sep;
}
memset(&hints, 0, sizeof hints);
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo(node, service, &hints, &ais);
if ( error ) {
fd_printf(STDERR_FILENO, "%s/%s: %s\r\n", node, service,
gai_strerror(error));
goto out;
}
/* Attempt each address in sequence */
for ( ai = ais; ai; ai = ai->ai_next ) {
fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
if ( fd == -1 )
continue;
if ( connect(fd, ai->ai_addr, ai->ai_addrlen) == 0 )
break;
close(fd);
fd = -1;
}
if ( fd == -1 )
fd_printf(STDERR_FILENO, "%s/%s: %s\r\n", node, service,
strerror(errno));
freeaddrinfo(ais);
if ( fd != -1 ) {
/* Enable nonblocking mode */
/* Not all systems can pass SOCK_NONBLOCK to socket() */
fl = fcntl(fd, F_GETFL);
fl |= O_NONBLOCK;
fcntl(fd, F_SETFL, fl);
}
out:
free(node);
return fd;
}
/* Closes a TCP socket to a host. See "tn2217.h". */
int
tn2217_close(int fd, int drain)
{
char buff[1024];
long fl;
int n;
if ( ! drain )
return close(fd);
/* FIXME(npat): Maybe protect the "reading until server closes"
with a large-ish timeout? */
fl = fcntl(fd, F_GETFL);
fl &= ~O_NONBLOCK;
fcntl(fd, F_SETFL, fl);
shutdown(fd, SHUT_WR);
do {
n = read(fd, buff, sizeof(buff));
} while ( n > 0 );
if ( n < 0 )
return n;
return close(fd);
}
/* Sends {IAC SB COMPORT <cmd> <data> IAC SE} */
static int
comport_send_cmd(struct term_s *t, unsigned char cmd,
const void *data, unsigned int datalen)
{
unsigned char msg[4] = { IAC, SB, TELOPT_COMPORT, cmd };
static const unsigned char end[2] = { IAC, SE };
/* assert(cmd != IAC); */
if ( writen_ni(t->fd, msg, sizeof msg) != sizeof msg )
goto werror;
if (datalen)
if ( escape_write(t, data, datalen) != datalen )
goto werror;
if ( writen_ni(t->fd, end, sizeof end) != sizeof end )
goto werror;
return 0;
werror:
term_errno = TERM_EOUTPUT;
return -1;
}
/* Sends a COM-PORT command consisting of a single byte (a common case) */
static int
comport_send_cmd1(struct term_s *t, unsigned char cmd,
unsigned char data)
{
return comport_send_cmd(t, cmd, &data, 1);
}
/* Sends a COM-PORT command with a 4-byte integer argument */
static int
comport_send_cmd4(struct term_s *t, unsigned char cmd, unsigned int val)
{
unsigned char valbuf[4];
/* Convert the value to network endian */
valbuf[0] = (val >> 24) & 0xff;
valbuf[1] = (val >> 16) & 0xff;
valbuf[2] = (val >> 8) & 0xff;
valbuf[3] = (val >> 0) & 0xff;
return comport_send_cmd(t, cmd, valbuf, sizeof valbuf);
}
/* Sends a SET-BAUDRATE message to the remote */
static int
comport_send_set_baudrate(struct term_s *t, int speed)
{
struct tn2217_state *s = STATE(t);
int r;
if (speed >= 0) {
r = comport_send_cmd4(t, COMPORT_SET_BAUDRATE, speed);
if ( r < 0 ) return r;
s->conf_pending++;
}
return 0;
}
/* Sends a SET-DATASIZE message to the remote */
static int
comport_send_set_datasize(struct term_s *t, int databits)
{
struct tn2217_state *s = STATE(t);
unsigned char val;
int r;
switch (databits) {
case 5: val = COMPORT_DATASIZE_5; break;
case 6: val = COMPORT_DATASIZE_6; break;
case 7: val = COMPORT_DATASIZE_7; break;
default: val = COMPORT_DATASIZE_8; break;
}
r = comport_send_cmd1(t, COMPORT_SET_DATASIZE, val);
if ( r < 0 ) return r;
s->conf_pending++;
return 0;
}
/* Sends a SET-PARITY message to the remote */
static int
comport_send_set_parity(struct term_s *t, enum parity_e parity)
{
struct tn2217_state *s = STATE(t);
unsigned char val;
int r;
switch (parity) {
case P_ODD: val = COMPORT_PARITY_ODD; break;
case P_EVEN: val = COMPORT_PARITY_EVEN; break;
default: val = COMPORT_PARITY_NONE; break;
}
r = comport_send_cmd1(t, COMPORT_SET_PARITY, val);
if ( r < 0 ) return r;
s->conf_pending++;
return 0;
}
/* Sends a SET-STOPSIZE message to the remote */
static int
comport_send_set_stopsize(struct term_s *t, int stopbits)
{
struct tn2217_state *s = STATE(t);
int r;
if (stopbits == 2)
r = comport_send_cmd1(t, COMPORT_SET_STOPSIZE,
COMPORT_STOPSIZE_2);
else
r = comport_send_cmd1(t, COMPORT_SET_STOPSIZE,
COMPORT_STOPSIZE_1);
if ( r < 0 ) return r;
s->conf_pending++;
return 0;
}
/* Sends a SET-CONTROL message to control hardware flow control */
static int
comport_send_set_fc(struct term_s *t, enum flowcntrl_e flow)
{
struct tn2217_state *s = STATE(t);
unsigned char val;
int r;
switch (flow) {
case FC_RTSCTS:
val = COMPORT_CONTROL_FC_HARDWARE;
break;
case FC_XONXOFF:
val = COMPORT_CONTROL_FC_XONOFF;
break;
case FC_NONE:
default:
val = COMPORT_CONTROL_FC_NONE;
break;
}
r = comport_send_cmd1(t, COMPORT_SET_CONTROL, val);
if ( r < 0 ) return r;
s->conf_pending++;
return 0;
}
/* Sends a SET-CONTROL message to control remote DTR state */
static int
comport_send_set_dtr(struct term_s *t, int modem)
{
unsigned char val;
if (modem & MCTL_DTR)
val = COMPORT_CONTROL_DTR_ON;
else
val = COMPORT_CONTROL_DTR_OFF;
return comport_send_cmd1(t, COMPORT_SET_CONTROL, val);
}
/* Sends a SET-CONTROL message to control remote RTS state */
static int
comport_send_set_rts(struct term_s *t, int modem)
{
unsigned char val;
if (modem & MCTL_RTS)
val = COMPORT_CONTROL_RTS_ON;
else
val = COMPORT_CONTROL_RTS_OFF;
return comport_send_cmd1(t, COMPORT_SET_CONTROL, val);
}
static int
comport_config_port(struct term_s *t, const struct termios *tios)
{
struct tn2217_state *s = STATE(t);
int r;
if (tios) {
r = comport_send_set_baudrate(t, tios_get_baudrate(tios, NULL));
if (r < 0) return r;
r = comport_send_set_datasize(t, tios_get_databits(tios));
if (r < 0) return r;
r = comport_send_set_parity(t, tios_get_parity(tios));
if (r < 0) return r;
r = comport_send_set_stopsize(t, tios_get_stopbits(tios));
if (r < 0) return r;
r = comport_send_set_fc(t, tios_get_flowcntrl(tios));
if (r < 0) return r;
} else {
/* If we're not going to specify it, ask for
* the current com port geometry. */
r = comport_send_cmd4(t, COMPORT_SET_BAUDRATE,
COMPORT_BAUDRATE_REQUEST);
if (r < 0) return r;
s->conf_pending ++;
r = comport_send_cmd1(t, COMPORT_SET_DATASIZE,
COMPORT_DATASIZE_REQUEST);
if (r < 0) return r;
s->conf_pending ++;
r = comport_send_cmd1(t, COMPORT_SET_PARITY,
COMPORT_PARITY_REQUEST);
if (r < 0) return r;
s->conf_pending ++;
r = comport_send_cmd1(t, COMPORT_SET_STOPSIZE,
COMPORT_STOPSIZE_REQUEST);
if (r < 0) return r;
s->conf_pending ++;
r = comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_FC_REQUEST);
if (r < 0) return r;
s->conf_pending ++;
}
return 0;
}
/* Called when the COM-PORT option frist becomes available.
* Sends initial COM-PORT setup, and requests the remote send its
* COM-PORT state. */
static int
comport_start(struct term_s *t)
{
struct tn2217_state *s = STATE(t);
int r;
/* Request the remote's server identifier. (Optional) */
r = comport_send_cmd(t, COMPORT_SIGNATURE, "", 0);
if ( r < 0 ) return r;
/* Ask for ongoing status updates for modem signal lines */
r = comport_send_cmd1(t, COMPORT_SET_LINESTATE_MASK, 0);
if ( r < 0 ) return r;
r = comport_send_cmd1(t, COMPORT_SET_MODEMSTATE_MASK,
MODEMSTATE_MASK);
if ( r < 0 ) return r;
if (s->set_termios) {
r = comport_config_port(t, &s->termios);
} else {
r = comport_config_port(t, NULL);
}
if ( r < 0 ) return r;
if (s->set_modem) {
r = comport_send_set_dtr(t, s->modem);
if ( r < 0 ) return r;
r = comport_send_set_rts(t, s->modem);
if ( r < 0 ) return r;
} else {
r = comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_DTR_REQUEST);
if ( r < 0 ) return r;
r = comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_RTS_REQUEST);
if ( r < 0 ) return r;
}
/* Also ask for the current break state */
return comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_BREAK_REQUEST);
}
/* Handle receipt of {IAC SB COMPORT <cmd> <data> IAC SE} command. */
static int
comport_recv_cmd(struct term_s *t, unsigned char cmd,
unsigned char *data, unsigned int datalen)
{
struct tn2217_state *s = STATE(t);
int val;
struct termios *tio = &s->termios;
int *modem = &s->modem;
int r;
/* The server sends its responses using IDs offset from
* COMPORT_SERVER_BASE. */
if (cmd < COMPORT_SERVER_BASE)
return 0;
cmd -= COMPORT_SERVER_BASE;
switch (cmd) {
case COMPORT_SIGNATURE: /* Exchange software "signature" text */
/* This is optional, but we might later exploit it to achieve
* server-specific workarounds. */
if (datalen)
DB(DB_CMP, "[received: SIGNATURE: '%.*s']\r\n", datalen, data);
else {
const char *sig = "picocom v" VERSION_STR;
r = comport_send_cmd(t, COMPORT_SIGNATURE,
sig, strlen(sig));
if ( r < 0 ) return -1;
DB(DB_CMP, "[sent: SIGNATURE: '%s']", sig);
}
break;
case COMPORT_SET_BAUDRATE: /* Remote baud rate update */
if (datalen >= 4) {
unsigned int baud = (data[0] << 24) | (data[1] << 16) |
(data[2] << 8) | data[3];
tios_set_baudrate_always(&s->termios, baud);
DB(DB_CMP, "[received: COMPORT BAUDRATE: %d]\r\n", baud);
}
/* XXX the sredird server sends an extra 4-byte value,
* which looks like the ispeed. It is not in the RFC. */
s->conf_pending--;
break;
case COMPORT_SET_DATASIZE: /* Notification of remote data bit size */
if (datalen >= 1) {
int val = 0;
switch (data[0]) {
case COMPORT_DATASIZE_5: val = 5; break;
case COMPORT_DATASIZE_6: val = 6; break;
case COMPORT_DATASIZE_7: val = 7; break;
case COMPORT_DATASIZE_8: val = 8; break;
}
tios_set_databits(tio, val);
DB(DB_CMP, "[received: COMPORT DATASIZE: %d]\r\n", val);
}
s->conf_pending--;
break;
case COMPORT_SET_PARITY: /* Remote parity update */
if (datalen >= 1) {
enum parity_e val = P_ERROR;
switch (data[0]) {
case COMPORT_PARITY_NONE: val = P_NONE; break;
case COMPORT_PARITY_ODD: val = P_ODD; break;
case COMPORT_PARITY_EVEN: val = P_EVEN; break;
}
tios_set_parity(tio, val);
DB(DB_CMP, "[received: COMPORT PARITY: %s]\r\n", parity_str[val]);
}
s->conf_pending--;
break;
case COMPORT_SET_STOPSIZE: /* Remote stop bits update */
if (datalen >= 1) {
int val = 0;
switch (data[0]) {
case COMPORT_STOPSIZE_1: val = 1; break;
case COMPORT_STOPSIZE_2: val = 2; break;
}
tios_set_stopbits(tio, val);
DB(DB_CMP, "[received: COMPORT STOPSIZE: %d]\r\n", val);
}
s->conf_pending--;
break;
case COMPORT_SET_CONTROL: /* Remote control state update */
if (datalen >= 1) {
switch (data[0]) {
/* Flow control changes and COMPORT_CONTROL_FC_REQUEST reply */
case COMPORT_CONTROL_FC_XONOFF:
tios_set_flowcntrl(tio, FC_XONXOFF);
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: FLOW: %s]\r\n",
data[0], flow_str[FC_XONXOFF]);
s->conf_pending--;
break;
case COMPORT_CONTROL_FC_HARDWARE:
tios_set_flowcntrl(tio, FC_RTSCTS);
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: FLOW: %s]\r\n",
data[0], flow_str[FC_RTSCTS]);
s->conf_pending--;
break;
case COMPORT_CONTROL_FC_NONE:
case COMPORT_CONTROL_FC_DCD:
case COMPORT_CONTROL_FC_DSR:
tios_set_flowcntrl(tio, FC_NONE);
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: FLOW: %s]\r\n",
data[0], flow_str[FC_NONE]);
s->conf_pending--;
break;
/* DTR changes and COMPORT_CONTROL_DTR_REQUEST reply */
case COMPORT_CONTROL_DTR_ON:
case COMPORT_CONTROL_DTR_OFF:
val = (data[0] == COMPORT_CONTROL_DTR_ON) ? MCTL_DTR : 0;
*modem &= ~MCTL_DTR;
*modem |= val;
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: dtr=%u]\r\n",
data[0], !!val);
break;
/* RTS changes and COMPORT_CONTROL_RTS_REQUEST reply */
case COMPORT_CONTROL_RTS_ON:
case COMPORT_CONTROL_RTS_OFF:
val = (data[0] == COMPORT_CONTROL_RTS_ON) ? MCTL_RTS : 0;
*modem &= ~MCTL_RTS;
*modem |= val;
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: rts=%u]\r\n",
data[0], !!val);
break;
default:
DB(DB_CMP, "[received: COMPORT SET_CONTROL: %d: (?)]\r\n", data[0]);
break;
}
}
break;
case COMPORT_NOTIFY_MODEMSTATE: /* Remote modem signal update */
/* Updates are masked by COMPORT_SET_MODEMSTATE_MASK elsewhere */
if (datalen >= 1) {
val = 0;
if (data[0] & COMPORT_MODEM_CD) val |= MCTL_DCD;
if (data[0] & COMPORT_MODEM_RI) val |= MCTL_RI;
if (data[0] & COMPORT_MODEM_DSR) val |= MCTL_DSR;
if (data[0] & COMPORT_MODEM_CTS) val |= MCTL_CTS;
DB(DB_CMP, "[received: COMPORT MODEMSTATE: %s]\r\n", repr_modem(val));
*modem &= ~(MCTL_DCD|MCTL_RI|MCTL_DSR|MCTL_CTS);
*modem |= val;
}
break;
default:
if ( DB_ON(DB_CMP) ) {
int i;
DB(DB_CMP, "[received: COMPORT CMD=%d:", cmd);
for ( i = 0; i < datalen; i++ )
DB(DB_CMP, " %d", data[i]);
DB(DB_CMP, "]\r\n");
}
break;
}
return 0;
}
static int
tn2217_init(struct term_s *t)
{
struct tn2217_state *s;
int r;
t->priv = calloc(1, sizeof (struct tn2217_state));
if ( ! t->priv ) {
term_errno = TERM_EMEM;
return -1;
}
s = STATE(t);
/* We don't yet know the remote's com port state, but
* let's assume it is raw. We will ask for updates later when
* the COM-PORT option is negotiated. */
cfmakeraw(&s->termios);
cfsetospeed(&s->termios, B0); /* This means 'unknown'. */
cfsetispeed(&s->termios, B0); /* This means "same as ospeed" */
/* Normally DTR and RTS are asserted, but an update can change that */
s->modem = MCTL_DTR | MCTL_RTS;
/* Start the negotiations. */
r = opt_will(t, TELOPT_BINARY);
if ( r < 0 ) return r;
r = opt_do(t, TELOPT_BINARY);
if ( r < 0 ) return r;
r = opt_will(t, TELOPT_SGA);
if ( r < 0 ) return r;
r = opt_do(t, TELOPT_SGA);
if ( r < 0 ) return r;
r = opt_will(t, TELOPT_COMPORT);
if ( r < 0 ) return r;
return 0;
}
static void
tn2217_fini(struct term_s *t)
{
free(t->priv);
}
static int
tn2217_tcgetattr(struct term_s *t, struct termios *termios_out)
{
struct tn2217_state *s = STATE(t);
DB(DB_CMP, "[tcgetattr %s]\r\n", repr_termios(&s->termios));
*termios_out = s->termios;
return 0;
}
static int
tn2217_tcsetattr(struct term_s *t, int when, const struct termios *tio)
{
struct tn2217_state *s = STATE(t);
int rval = 0;
DB(DB_CMP, "[tcsetattr %s]\r\n", repr_termios(tio));
s->termios = *tio;
if (s->can_comport)
rval = comport_config_port(t, tio);
else
s->set_termios = 1;
return rval;
}
static int
tn2217_modem_get(struct term_s *t, int *modem_out)
{
struct tn2217_state *s = STATE(t);
DB(DB_CMP, "[modem_get %s]\r\n", repr_modem(s->modem));
*modem_out = s->modem;
return 0;
}
static int
tn2217_modem_bis(struct term_s *t, const int *modem)
{
struct tn2217_state *s = STATE(t);
int r;
DB(DB_CMP, "[modem_bis %s]\r\n", repr_modem(*modem));
s->modem |= *modem;
if (s->can_comport) {
if (*modem & MCTL_DTR) {
r = comport_send_set_dtr(t, MCTL_DTR);
if (r < 0) return r;
}
if (*modem & MCTL_RTS) {
r = comport_send_set_rts(t, MCTL_RTS);
if (r < 0) return r;
}
} else if (*modem & (MCTL_DTR|MCTL_RTS))
s->set_modem = 1;
return 0;
}
static int
tn2217_modem_bic(struct term_s *t, const int *modem)
{
struct tn2217_state *s = STATE(t);
int r;
DB(DB_CMP, "[modem_bic %s]\r\n", repr_modem(*modem));
s->modem &= ~*modem;
if (s->can_comport) {
if (*modem & MCTL_DTR) {
r = comport_send_set_dtr(t, 0);
if ( r < 0 ) return r;
}
if (*modem & MCTL_RTS) {
r = comport_send_set_rts(t, 0);
if ( r < 0 ) return r;
}
} else if (*modem & (MCTL_DTR|MCTL_RTS))
s->set_modem = 1;
return 0;
}
static int
tn2217_send_break(struct term_s *t)
{
int r;
/* FIXME(npat): Check can_comport? */
r = comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_BREAK_ON);
if ( r < 0 ) return r;
DB(DB_CMP, "[sent: COMPORT SET_CONTROL BREAK_ON]\r\n");
usleep(250000); /* 250 msec */
r = comport_send_cmd1(t, COMPORT_SET_CONTROL,
COMPORT_CONTROL_BREAK_OFF);
if ( r < 0 ) return r;
DB(DB_CMP, "[sent: COMPORT SET_CONTROL BREAK_OFF]\r\n");
return 0;
}
static int
tn2217_flush(struct term_s *t, int selector)
{
unsigned char val;
/* FIXME(npat): Check can_comport? */
/* Purge, presumably so that we have something to flush */
switch (selector) {
case TCIFLUSH: val = COMPORT_PURGE_RX; break;
case TCOFLUSH: val = COMPORT_PURGE_TX; break;
default: val = COMPORT_PURGE_RXTX; break;
}
DB(DB_CMP, "[sent: COMPORT PURGE_DATA %d]\r\n", val);
return comport_send_cmd1(t, COMPORT_PURGE_DATA, val);
}
/* Condition: Initial configuration completed. That is: initial
negotiations completed, configuration commands sent, *and*
replies received. To be used with wait_cond(). */
static int
cond_initial_conf_complete(struct term_s *t)
{
struct tn2217_state *s = STATE(t);
if ( s->configed ) return 1;
if ( s->can_comport && ! s->conf_pending ) {
s->configed = 1;
return 1;
}
return 0;
}
/* Condition: Initial negotiations completed, and configuration
commands sent, but replies not yet received. To be used with
wait_cond(). */
static int
cond_comport_start(struct term_s *t)
{
return STATE(t)->can_comport;
}
/* Wait (keep reading from the fd and processing commands) until the
condition is satisfied (that is, until "cond" returns non-zero), or
until the timeout expires. Returns a positive on success, zero if
read(2) returned zero, and a negative on any other error
(incl. timeoute expiration). On timeout expiration, term_errno is set to
TERM_ETIMEDOUT.*/
static int
wait_cond(struct term_s *t, int (*cond)(struct term_s *t), int tmo_msec)
{
struct timeval now, tmo_tv, tmo_abs;
unsigned char c;
int r;
fd_set rdset;
msec2tv(&tmo_tv, tmo_msec);
gettimeofday(&now, 0);
timeradd(&now, &tmo_tv, &tmo_abs);
while ( ! cond(t) ) {
FD_ZERO(&rdset);
FD_SET(t->fd, &rdset);
r = select(t->fd + 1, &rdset, 0, 0, &tmo_tv);
if ( r < 0 ) {
term_errno = TERM_ESELECT; return -1;
} else if ( r > 0 ) {
r = read_and_proc(t, &c, 1);
if ( r == 0 || (r < 0 && term_esys() != EAGAIN) )
return r;
/* discard c */
}
gettimeofday(&now, 0);
if ( timercmp(&now, &tmo_abs, <) ) {
timersub(&tmo_abs, &now, &tmo_tv);
} else {
/* Set both term_errno and errno so clients can check either */
term_errno = TERM_ETIMEDOUT;
errno = ETIMEDOUT;
return -1;
}
}
return 1;
}
/* Reads raw binary from the socket and immediately handles any
* in-stream TELNET commands. */
static int
read_and_proc(struct term_s *t, void *buf, unsigned bufsz)
{
struct tn2217_state *s = STATE(t);
unsigned char *in, *out;
int r, inlen, outlen;
unsigned char *iac;
inlen = read(t->fd, buf, bufsz);
if (inlen <= 0) {
if ( inlen < 0 ) term_errno = TERM_EINPUT;
return inlen;
}
in = out = (unsigned char *)buf;
outlen = 0;
while (inlen) {
while (s->cmdbuflen && inlen) {
/* We are currently appending to the command accumulator. */
if (s->cmdbuflen >= sizeof s->cmdbuf - 1) {
s->cmdbuflen = 0; /* Abandon on overflow */
pinfof("[overlong IAC command]\r\n");
break;
}
s->cmdbuf[s->cmdbuflen++] = *in++;
inlen--;
if (s->cmdbuflen == 2 && s->cmdbuf[1] == IAC) {
/* Handle {IAC IAC} escaping immediately */
*out++ = IAC;
outlen++;
s->cmdbuflen = 0;
} else {
/* Handle {IAC ...} accumulations byte-at-a-time.
* s->cmdbuflen will be cleared on each completion */
r = recv_cmd_partial(t);
if ( r < 0 ) return r;
}
}
/* Not currently in an IAC command. Look for the start of one. */
iac = (unsigned char *)memchr(in, IAC, inlen);
if (iac) {
int priorlen = iac - in;
/* Copy out the user data prior to the IAC */
memmove(out, in, priorlen);
out += priorlen;
outlen += priorlen;
/* Make cmdbuf[] non-empty to indicate that we've entered
* a TELNET command */
s->cmdbuf[0] = IAC;
s->cmdbuflen = 1;
/* Remove the IAC and copied-out data from the input buffer */
inlen -= priorlen + 1;
in += priorlen + 1;
} else {
/* Everything is user data. Copy it out */
memmove(out, in, inlen);
outlen += inlen;
inlen = 0;
}
}
if (outlen == 0) {
/* If all we processed were TELNET commands, we can't return 0
* because that would falsely indicate an EOF condition. Instead,
* signal EAGAIN. See the article "Worse is Better".
*/
term_errno = TERM_EINPUT;
errno = EAGAIN;
outlen = -1;
}
return outlen;
}
/* Reads raw binary from the socket and immediately handles any
* in-stream TELNET commands. */
static int
tn2217_read(struct term_s *t, void *buf, unsigned bufsz)
{
int r;
/* If s->set_termios is not set (i.e. --noinit was given), the
port will not be configured and we don't have to wait. */
if ( STATE(t)->set_termios && ! cond_initial_conf_complete(t) ) {
/* Port may not have been configured yet. Wait for
negotiations to end, and configuration commands to get
transmitted *and* replies received. */
DBG("tn2217_read WAITING initial_conf_complete\r\n");
r = wait_cond(t, cond_initial_conf_complete, 5000);
if ( r <= 0 )
return r;
DBG("tn2217_read GOT initial_conf_complete\r\n");
}
return read_and_proc(t, buf, bufsz);
}
static int
escape_write(struct term_s *t, const void *buf, unsigned bufsz)
{
const unsigned char *start, *end;
unsigned int n, len;
len = bufsz;
start = (const unsigned char *)buf;
/* Double instances of IAC by arranging for overlapping writes. */
end = (const unsigned char *)memchr(start, IAC, len);
while (end) {
n = (end - start) + 1;
if ( writen_ni(t->fd, start, n) != n ) {
term_errno = TERM_EOUTPUT; return -1;
}
len -= end - start;
start = end;
end = (const unsigned char *)memchr(start + 1, IAC, len - 1);
}
if ( writen_ni(t->fd, start, len) != len ) {
term_errno = TERM_EOUTPUT; return -1;
return -1;
}
return bufsz;
}
static int
tn2217_write(struct term_s *t, const void *buf, unsigned bufsz)
{
int r;
/* If s->set_termios is not set (i.e. --noinit was given), the
port will not be configured and we don't have to wait. */
if ( STATE(t)->set_termios && ! cond_comport_start(t) ) {
/* Port may not have been configured yet. Wait for
negotiations to end, and configuration commands to get
transmitted. It is not necessary to wait for them to get
replied. */
DBG("tn2217_write WAITING comport_start\r\n");
r = wait_cond(t, cond_comport_start, 5000);
if ( r <= 0 ) {
if ( r == 0 ) term_errno = TERM_ERDZERO;
return -1;
}
DBG("tn2217_write GOT comport_start\r\n");
}
return escape_write(t, buf, bufsz);
}
const struct term_ops tn2217_ops = {
.init = tn2217_init,
.fini = tn2217_fini,
.tcgetattr = tn2217_tcgetattr,
.tcsetattr = tn2217_tcsetattr,
.modem_get = tn2217_modem_get,
.modem_bis = tn2217_modem_bis,
.modem_bic = tn2217_modem_bic,
.send_break = tn2217_send_break,
.flush = tn2217_flush,
.fake_flush = NULL,
.drain = NULL,
.read = tn2217_read,
.write = tn2217_write,
};
/***************************************************************************/
/*
* Local Variables:
* mode:c
* tab-width: 4
* c-basic-offset: 4
* End:
*/
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