fix missing deref of tty data when destroyed (#2)

This patch allows multiple clients to open the ttynvt device at the same time.
This is useful if an application wants to get/set termios (ioctls) while the
device is already opened by an other application.

.gitignore

@@ -3,10 +3,12 @@
 /autom4te.cache/
 /compile
 /config.h.in
-/config.h.in~
+/config.guess
+/config.sub
 /configure
 /depcomp
 /install-sh
+/ltmain.sh
 /missing
 Makefile.in
 

Makefile.am

@@ -4,4 +4,8 @@ MAINTAINERCLEANFILES = \
 	depcomp install-sh missing \
 	Makefile.in */Makefile.in
 
-SUBDIRS = src
+SUBDIRS = lib src
+if BUILD_TESTTOOLS
+SUBDIRS += nvtsrv
+SUBDIRS += nvttest
+endif

configure.ac

@@ -1,9 +1,6 @@
-m4_define([pkg_version],  [0.14])
-#m4_define([pkg_revision], [005])
-m4_define([pkg_version],  m4_ifdef([pkg_revision], [pkg_version.pkg_revision], [pkg_version]))
-
-AC_INIT([ttynvt],[pkg_version],[frj@thrane.eu])
+AC_INIT([ttynvt],[0.16],[frj@thrane.eu])
 AM_INIT_AUTOMAKE([foreign dist-xz])
+
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
 AC_USE_SYSTEM_EXTENSIONS
@@ -12,12 +9,12 @@ AC_PROG_CC
 
 AC_PROG_INSTALL
 
-AC_HEADER_STDC
-
 define([AC_LIBTOOL_LANG_CXX_CONFIG], [:])dnl
 define([AC_LIBTOOL_LANG_F77_CONFIG], [:])dnl
 define([AC_LIBTOOL_LANG_GCJ_CONFIG], [:])dnl
 
+LT_INIT()
+
 AC_C_BIGENDIAN
 AC_C_CONST
 AC_C_INLINE
@@ -29,10 +26,24 @@ PKG_PROG_PKG_CONFIG
 
 PKG_CHECK_MODULES(FUSE, fuse)
 
+AC_ARG_ENABLE(testtools,
+  AS_HELP_STRING([--enable-testtools], [Build test tools @<:@default=no@:>@]),,
+  enable_testtools=no)
+AM_CONDITIONAL([BUILD_TESTTOOLS], [test "x$enable_testtools" = "xyes"])
+
+CFLAGS_WARN="$CFLAGS_WARN -Wall -Wextra -Werror -Wno-unused-parameter"
+CFLAGS_WARN="$CFLAGS_WARN -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes"
+CFLAGS_WARN="$CFLAGS_WARN -Waggregate-return -Wpointer-arith -Wshadow -Wwrite-strings"
+CFLAGS_WARN="$CFLAGS_WARN -Wcast-align -Wcast-qual"
+AC_SUBST(CFLAGS_WARN)
+
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([
 Makefile
+lib/Makefile
 src/Makefile
+nvtsrv/Makefile
+nvttest/Makefile
 ])
 AC_OUTPUT
 

lib/Makefile.am

@@ -0,0 +1,6 @@
+noinst_LTLIBRARIES = libnvt.la
+
+libnvt_la_CFLAGS = $(CFLAGS_WARN)
+
+libnvt_la_SOURCES  = nvt_log.c nvt_log.h
+libnvt_la_SOURCES += nvt_socket.c nvt_socket.h

lib/nvt_log.c

@@ -14,7 +14,34 @@
 #define gettid() (pid_t)syscall(__NR_gettid)
 
 char            log_level = 0;
-char            log_stdout = 0;
+
+static char     log_threshold = LOG_DEBUG;
+
+static FILE    *log_dest = NULL;
+
+void nvt_log_dest(int dest)
+{
+    switch (dest)
+    {
+    default:
+    case NVT_LOG_SYSLOG:
+        log_dest = NULL;
+        break;
+    case NVT_LOG_STDOUT:
+        log_dest = stdout;
+        break;
+    case NVT_LOG_STDERR:
+        log_dest = stderr;
+        break;
+    }
+}
+
+void nvt_log_level(int quiet, int level)
+{
+    if (quiet)
+        log_threshold = LOG_NOTICE;
+    log_level = level;
+}
 
 static const char *_hms_txt(char *buf, unsigned int len)
 {
@@ -40,13 +67,16 @@ void nvt_log(int prio, const char *fmt, ...)
     const char     *eol;
     int             len;
 
+    if (prio > log_threshold)
+        return;
+
     va_start(arg, fmt);
     len = vsnprintf(buf, sizeof(buf), fmt, arg);
 
-    if (log_stdout)
+    if (log_dest)
     {
         eol = (len > 0 && buf[len - 1] != '\n') ? "\n" : "";
-        printf("%s: [%d] %d: %s%s",
+        fprintf(log_dest, "%s: [%d] %d: %s%s",
                 _hms_txt(buft, sizeof(buft)), gettid(), prio, buf, eol);
     }
     else

lib/nvt_log.h

@@ -9,12 +9,17 @@
 #define _PRF_N_(no) __attribute__((__format__(__printf__, (no), (no) + 1)))
 #define _PRF2_ _PRF_N_(2)
 
+void            nvt_log_dest(int dest);
+void            nvt_log_level(int quiet, int level);
 _PRF2_ void     nvt_log(int prio, const char *fmt, ...);
 void            nvt_log_buf(int prio, const char *txt,
                             const void *ptr, unsigned int len);
 
+#define NVT_LOG_SYSLOG  0
+#define NVT_LOG_STDOUT  1
+#define NVT_LOG_STDERR  2
+
 extern char     log_level;
-extern char     log_stdout;
 
 #define DBG(...) \
     if (log_level > 0) nvt_log(LOG_DEBUG, __VA_ARGS__)

lib/nvt_socket.c

@@ -0,0 +1,149 @@
+/*
+ * Socket interface API
+ */
+#include <netdb.h>              /* getaddrinfo() */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+
+#include "nvt_log.h"
+#include "nvt_socket.h"
+
+
+typedef struct {
+    unsigned short  type;       // socket type
+    unsigned short  slen;       // sockaddr length
+    union {
+        struct sockaddr gen;
+        struct sockaddr_in ipv4;
+    };
+} sa_t;
+
+
+static int _sa_host_lookup(sa_t * sa, const char *host)
+{
+    struct hostent *server;
+
+    server = gethostbyname(host);
+    if (server == NULL)
+    {
+        nvt_log(LOG_ERR, "Cannot resolve host name: %m\n");
+        return -1;
+    }
+
+    sa->slen = sizeof(sa->ipv4);
+
+    sa->ipv4.sin_family = AF_INET;
+    memcpy(&sa->ipv4.sin_addr.s_addr, server->h_addr, server->h_length);
+
+    return 0;
+}
+
+static int _sa_addr_parse(sa_t * sa, const char *addr)
+{
+    char            host[64], port[64];
+
+    memset(sa, 0, sizeof(sa_t));
+
+    sscanf(addr, "%63[^:]:%63s", host, port);
+
+    if (_sa_host_lookup(sa, host) != 0)
+        return -1;
+
+    sa->type = SOCK_STREAM;
+    sa->ipv4.sin_port = htons(atoi(port));
+
+    return 0;
+}
+
+int socket_create_client(const char *addr)
+{
+    sa_t            sa;
+    int             fd, err;
+
+    if (_sa_addr_parse(&sa, addr) != 0)
+        return -1;
+
+    fd = socket(sa.gen.sa_family, sa.type, 0);
+    if (fd < 0)
+    {
+        nvt_log(LOG_ERR, "%s: Could not find address: '%s'", __func__, addr);
+        return fd;
+    }
+
+    err = connect(fd, &sa.gen, sa.slen);
+    if (err < 0)
+    {
+        nvt_log(LOG_ERR, "Failed to connect to: %s: %m\n", addr);
+        close(fd);
+        return -1;
+    }
+
+    return fd;
+}
+
+int socket_create_server(const char *addr)
+{
+    sa_t            sa;
+    int             err, fd, opt;
+
+    err = _sa_addr_parse(&sa, addr);
+    if (err != 0)
+    {
+        nvt_log(LOG_ERR, "%s: Could not find address: '%s'", __func__, addr);
+        return -1;
+    }
+
+    fd = socket(sa.gen.sa_family, sa.type, 0);
+    if (fd < 0)
+    {
+        nvt_log(LOG_ERR, "%s: *** socket(%s): %m", __func__, addr);
+        return -1;
+    }
+
+    if (sa.gen.sa_family == AF_INET)
+    {
+        /* Avoid TIME_WAIT state on socket close */
+        opt = 1;
+        setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    }
+
+    err = bind(fd, &sa.gen, sa.slen);
+    if (err != 0)
+    {
+        nvt_log(LOG_ERR, "%s: *** bind(%s): %m", __func__, addr);
+        close(fd);
+        return -1;
+    }
+
+    if (sa.type == SOCK_STREAM)
+    {
+        err = listen(fd, 5);
+        if (err != 0)
+        {
+            nvt_log(LOG_ERR, "%s: *** listen(%s): %m", __func__, addr);
+            close(fd);
+            return -1;
+        }
+    }
+
+    return fd;
+}
+
+int socket_create_server_client(int sfd)
+{
+    int             cfd;
+    socklen_t       slen;
+
+    slen = 0;
+    cfd = accept(sfd, NULL, &slen);
+    if (cfd < 0)
+    {
+        nvt_log(LOG_ERR, "%s: *** accept(): %m", __func__);
+        return -1;
+    }
+
+    return cfd;
+}

lib/nvt_socket.h

@@ -0,0 +1,12 @@
+/*
+ * Socket functions
+ */
+#ifndef NVT_SOCKET_H
+#define NVT_SOCKET_H
+
+int             socket_create_client(const char *addr);
+
+int             socket_create_server(const char *addr);
+int             socket_create_server_client(int sfd);
+
+#endif /* NVT_SOCKET_H */

nvtsrv/Makefile.am

@@ -0,0 +1,10 @@
+
+bin_PROGRAMS = nvtsrv
+
+nvtsrv_SOURCES = \
+	nvtsrv.c		\
+	telnet_basic.c telnet_server_rfc2217.c telnet.h telnet_param.h
+
+nvtsrv_CPPFLAGS = -I$(top_builddir) -I$(top_srcdir) $(CFLAGS_WARN)
+
+nvtsrv_LDADD = $(top_builddir)/lib/libnvt.la

nvtsrv/nvtsrv.c

@@ -0,0 +1,240 @@
+/*
+ * RFC2217 test server
+ */
+#include <poll.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "lib/nvt_log.h"
+#include "lib/nvt_socket.h"
+#include "telnet.h"
+
+
+#define HELP \
+    "Usage: nvtsrv -deq\n"
+
+
+struct {
+    unsigned char   mline;
+    tn_ctx_t       *tnct;
+} dd;
+
+struct pollfd   pfds[3];
+int             nfds;
+
+#define fd_srv pfds[1].fd
+#define fd_cli pfds[2].fd
+
+
+static void _nvtsrv_usage(void)
+{
+    printf("Usage:\n" " nvtsrv host:port\n");
+    exit(0);
+}
+
+static void _tn_cli_close(void)
+{
+    int             i = 2;
+
+    nvt_log(LOG_INFO, "%d: fd=%d: Closed\n", i, pfds[i].fd);
+    close(pfds[i].fd);
+    pfds[i].fd = -1;
+    nfds = 2;
+}
+
+static void _tn_tx(void *cctx, const void *buf, int len)
+{
+    int             nw;
+
+    DBG2_BUF("Tx", buf, len);
+
+    if (fd_cli < 0)
+    {
+        nvt_log(LOG_NOTICE, "Write fd is closed - drop Tx\n");
+        return;
+    }
+
+    nw = write(fd_cli, buf, len);
+    if (nw != len)
+    {
+        nvt_log(LOG_ERR, "Write failed %d != %d\n", nw, len);
+        _tn_cli_close();
+    }
+}
+
+static void _tn_ss(void *cctx, int signal, int value)
+{
+    nvt_log(LOG_INFO, "RFC2217 signal %d: %02x", signal, value);
+}
+
+static void _nvtsrv_init(void)
+{
+    free(dd.tnct);
+
+    memset(&dd, 0, sizeof(dd));
+
+    dd.tnct = telnet_ctx_init(NULL, _tn_tx, _tn_ss);
+}
+
+static void _nvtsrv_cmd(tn_ctx_t * tcc, const char *line, int len)
+{
+    int             val;
+
+    if (line[0] == '*' && len > 2)
+    {
+        /* Special features */
+        if (line[1] == 'm')
+        {
+            sscanf(line + 2, "%x", &val);
+            telnet_rfc2217_change_modemstate(tcc, val);
+        }
+    }
+    else
+    {
+        /* Send all input */
+        _tn_tx(NULL, line, len);
+    }
+}
+
+static void _nvtsrv_set_signal_handlers(void)
+{
+    struct sigaction sa = {
+        .sa_handler = SIG_IGN,
+        .sa_flags = SA_RESTART,
+    };
+
+    sigemptyset(&sa.sa_mask);
+    sigaction(SIGPIPE, &sa, NULL);
+}
+
+int main(int argc, char **argv)
+{
+    int             opt;
+    char            buf[128];
+    int             rc, nr, i, len;
+    int             debug, quiet;
+    bool            do_echo;
+
+    debug = quiet = 0;
+    do_echo = false;
+
+    while ((opt = getopt(argc, argv, "deq")) != -1)
+    {
+        switch (opt)
+        {
+        default:               /* '?' */
+            fprintf(stderr, HELP);
+            exit(EXIT_FAILURE);
+        case 'd':
+            debug += 1;
+            break;
+        case 'e':              /* Echo received data */
+            do_echo = true;
+            break;
+        case 'q':
+            quiet = 1;
+            break;
+        }
+    }
+
+    argc -= optind;
+    argv += optind;
+    if (argc <= 0)
+        _nvtsrv_usage();
+
+    nvt_log_level(quiet, debug);
+    nvt_log_dest(NVT_LOG_STDOUT);
+
+    _nvtsrv_set_signal_handlers();
+
+    memset(pfds, 0, sizeof(pfds));
+
+    pfds[0].fd = STDIN_FILENO;
+    pfds[0].events = POLLIN;
+
+    pfds[1].fd = socket_create_server(argv[0]);
+    pfds[1].events = POLLIN;
+
+    pfds[2].fd = -1;
+    pfds[2].events = POLLIN;
+
+    nfds = 2;
+
+    for (;;)
+    {
+        for (i = 0; i < 3; i++)
+            pfds[i].revents = 0;
+
+        rc = poll(pfds, nfds, -1);
+        if (rc < 0)
+        {
+            nvt_log(LOG_ERR, "poll failed: %m\n");
+            break;
+        }
+
+        i = 0;
+        if (pfds[i].revents)
+        {
+            nr = read(pfds[i].fd, buf, sizeof(buf) - 1);
+            if (nr <= 0)
+                break;
+            buf[nr] = 0;
+            DBG2_BUF("Con Rx", buf, nr);
+            _nvtsrv_cmd(dd.tnct, buf, nr);
+        }
+
+        i = 2;
+        if (pfds[i].revents)
+        {
+            nr = 0;
+            if (pfds[i].revents & POLLIN)
+            {
+                nr = read(pfds[i].fd, buf, sizeof(buf));
+                if (nr <= 0)
+                {
+                    _tn_cli_close();
+                    continue;
+                }
+            }
+            if (pfds[i].revents & (POLLERR | POLLHUP))
+            {
+                _tn_cli_close();
+            }
+
+            if (nr > 0)
+            {
+                buf[nr] = 0;
+                DBG2_BUF("Rx", buf, nr);
+                len = nr;
+                rc = telnet_rx(dd.tnct, buf, &len);
+                if (do_echo)
+                {
+                    /* Echo received */
+                    _tn_tx(NULL, buf, len);
+                }
+            }
+        }
+
+        i = 1;
+        if (pfds[i].revents)
+        {
+            if (pfds[2].fd >= 0)
+            {
+                nvt_log(LOG_NOTICE, "Client already connected on fd=%d\n",
+                        pfds[2].fd);
+                break;
+            }
+            pfds[2].fd = socket_create_server_client(pfds[i].fd);
+            nvt_log(LOG_INFO, "%d: fd=%d: Connected\n", 2, pfds[2].fd);
+            pfds[2].events = POLLIN;
+            nfds = 3;
+            _nvtsrv_init();
+        }
+    }
+
+    return 0;
+}

nvtsrv/telnet.h

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2018 Lars Thrane A/S
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Telnet interface - server
+ */
+#ifndef TELNET_SERVER_H
+#define TELNET_SERVER_H
+
+typedef void    (cli_tx_f) (void *cctx, const void *buf, int len);
+typedef void    (cli_ss_f) (void *cctx, int signal, int value);
+
+/* Telnet context */
+typedef struct {
+    void           *cctx;       /* Client context */
+
+    cli_tx_f       *cli_tx;     /* Write to client */
+    cli_ss_f       *cli_ss;     /* Signal from client */
+
+    unsigned int    bytes_rx;   /* Rx byte count */
+    unsigned int    off_rx;     /* Rx buffer offset */
+    unsigned char   mode_telnet;        /* Telnet mode */
+    unsigned char   mode_rfc2217;       /* RFC-2217 mode */
+
+    unsigned int    baudrate;
+    unsigned char   datasize;
+    unsigned char   parity;
+    unsigned char   stopsize;
+
+    unsigned char   linestate;
+    unsigned char   modemstate;
+
+    unsigned char   linestate_mask;
+    unsigned char   modemstate_mask;
+
+    char            dtr_state;
+    char            rts_state;
+} tn_ctx_t;
+
+extern tn_ctx_t *telnet_ctx_init(void *cctx, cli_tx_f * ftx, cli_ss_f * fss);
+
+extern int      telnet_rx(tn_ctx_t * tcc, char *buf, int *plen);
+extern int      telnet_tx(tn_ctx_t * tcc, const char *buf, int len);
+
+extern void     telnet_reply_opt(tn_ctx_t * tcc, int opt, int prm,
+                                 const void *val, int len);
+
+extern void     telnet_rfc2217_init(tn_ctx_t * tcc, int when);
+extern void     telnet_rfc2217_handle_opt(tn_ctx_t * tcc, int opt,
+                                          unsigned char *pu, int nd);
+
+extern void     telnet_rfc2217_change_linestate(tn_ctx_t * tcc, int mask);
+extern void     telnet_rfc2217_change_modemstate(tn_ctx_t * tcc, int mask);
+
+/* Init modes */
+#define TNI_INIT    0           /* Init context     */
+#define TNI_ON      1           /* Option activated */
+
+/* Signals that may be passed to cli_ss_f() */
+#define TNS_DTR     1
+#define TNS_RTS     2
+
+#endif /* TELNET_SERVER_H */

nvtsrv/telnet_basic.c

@@ -0,0 +1,275 @@
+/*
+ * Copyright (c) 2018 Lars Thrane A/S
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Telnet protocol handling - server
+ */
+#include <stdlib.h>
+#include <string.h>
+
+#include "lib/nvt_log.h"
+#include "telnet.h"
+#include "telnet_param.h"
+
+
+/* Telnet commands */
+static const char *const tn_cmd[] = {
+    "SE", "NOP", "MARK", "BRK", "IP", "AO", "AYT", "EC",
+    "EL", "GA", "SB", "WILL", "WONT", "DO", "DONT", "IAC"
+};
+
+#define OPT_NACK    0           /* Reject      (DONT/WONT)      */
+#define OPT_IGNORE  1           /* Ignore the command (?)       */
+#define OPT_ACK     2           /* Acknowledge (DO  /WILL)      */
+
+/* Telnet option support */
+static const unsigned char tn_opt[256] = {
+/* *INDENT-OFF* */
+    [TNO_BINARY] = OPT_ACK,
+    [TNO_SUPP_GA] = OPT_ACK,
+//  [TNO_TTYP]   = OPT_NACK,
+//  [TNO_NAWS]   = OPT_NACK,
+//  [TNO_NEO]    = OPT_NACK,
+    [TNO_CPCO]   = OPT_ACK,
+//  [TNO_KERMIT] = OPT_NACK,
+/* *INDENT-ON* */
+};
+
+
+static void _telnet_handle_req(tn_ctx_t * tcc, int cmd, int opt)
+{
+    char            buf[3];
+
+    switch (tn_opt[opt])
+    {
+    default:
+    case OPT_IGNORE:
+        return;
+    case OPT_ACK:
+        cmd = (cmd == TNC_FB_WILL) ? TNC_FD_DO : TNC_FB_WILL;
+        break;
+    case OPT_NACK:
+        cmd = (cmd == TNC_FB_WILL) ? TNC_FE_DONT : TNC_FC_WONT;
+        break;
+    }
+
+    buf[0] = TNC_FF_IAC;
+    buf[1] = cmd;
+    buf[2] = opt;
+    DBG("TNo: Op2 %02x %02x: %-4s %d", cmd, opt, tn_cmd[cmd & 0xf], opt);
+    tcc->cli_tx(tcc->cctx, buf, 3);
+
+    if (opt == TNO_CPCO && (cmd == TNC_FB_WILL || cmd == TNC_FD_DO))
+        telnet_rfc2217_init(tcc, TNI_ON);
+}
+
+void telnet_reply_opt(tn_ctx_t * tcc, int opt, int prm,
+                      const void *val, int len)
+{
+    unsigned char   buf[128], *pu = buf;
+    const unsigned char *pv;
+    int             i;
+
+    *pu++ = TNC_FF_IAC;
+    *pu++ = TNC_FA_SB;
+
+    *pu++ = opt;
+    *pu++ = prm;
+    if (len > 0 && len <= 32)
+    {
+        pv = val;
+        for (i = 0; i < len; i++)
+        {
+            *pu++ = *pv;
+            if (*pv++ == TNC_FF_IAC)
+                *pu++ = TNC_FF_IAC;
+        }
+    }
+
+    *pu++ = TNC_FF_IAC;
+    *pu++ = TNC_F0_SE;
+
+    len = pu - buf;
+    DBG2_BUF("opto", buf, len);
+    tcc->cli_tx(tcc->cctx, buf, len);
+}
+
+static void _telnet_handle_opt(tn_ctx_t * tcc, int opt,
+                               unsigned char *pu, int nd)
+{
+    DBG2_BUF("opti", pu, nd);
+
+    switch (opt)
+    {
+    default:
+        nvt_log(LOG_WARNING, "Unexpected SB: Opt = %d", opt);
+        break;
+    case TNO_CPCO:             /* RFC 2217 */
+        tcc->mode_rfc2217 = 1;
+        telnet_rfc2217_handle_opt(tcc, opt, pu, nd);
+        break;
+    }
+}
+
+int telnet_rx(tn_ctx_t * tcc, char *buf, int *plen)
+{
+    char           *s, *p;
+    unsigned char  *pu;
+    int             len, rem;
+    int             np, nd;
+    int             b1, b2;
+
+    /* Drop telnet processing entirely if we haven't seen any telnet
+     * negotiation in the beginning */
+    if (tcc->bytes_rx >= 32 && !tcc->mode_telnet)
+        return 0;
+
+    len = *plen;
+    tcc->bytes_rx += len;
+
+    if (len < (int)tcc->off_rx)
+        tcc->off_rx = 0;
+
+    for (s = buf + tcc->off_rx, rem = len - tcc->off_rx; rem > 0; s = p)
+    {
+        DBG2_BUF("****", s, rem);
+        p = memchr(s, TNC_FF_IAC, rem);
+        if (!p)
+            break;
+
+        /* We have IAC (= 0xff) */
+        np = rem - (p - s);     /* N. chars available incl. IAC */
+        if (np < 2)
+            goto tn_more;
+
+        pu = (unsigned char *)p;
+        b1 = pu[1];
+        switch (b1)
+        {
+        default:
+        case TNC_F0_SE:
+        case TNC_F1_NOP:
+        case TNC_F2_MARK:
+        case TNC_F3_BRK:
+        case TNC_F4_IP:
+        case TNC_F5_AO:
+        case TNC_F6_AYT:
+        case TNC_F7_EC:
+        case TNC_F8_EL:
+        case TNC_F9_GA:
+            DBG("TNi: Op1 %02x   : %s", b1, tn_cmd[b1 & 0xf]);
+            nd = 2;             /* Drop 2 bytes */
+            goto tn_drop;
+
+        case TNC_FB_WILL:
+        case TNC_FC_WONT:
+        case TNC_FD_DO:
+        case TNC_FE_DONT:
+            if (np < 3)
+                goto tn_more;   /* Need more */
+            tcc->mode_telnet = 1;       /* Any such sequence activates TN */
+            b2 = pu[2];
+            DBG("TNi: Op2 %02x %02x: %-4s %d", b1, b2, tn_cmd[b1 & 0xf], b2);
+            if (b1 == TNC_FB_WILL || b1 == TNC_FD_DO)
+                _telnet_handle_req(tcc, b1, b2);
+            nd = 3;             /* Drop 3 bytes */
+            goto tn_drop;
+
+        case TNC_FA_SB:
+            for (nd = 2; nd < np - 1; nd++)
+            {
+                if (pu[nd] == TNC_FF_IAC && pu[nd + 1] == TNC_F0_SE)
+                {
+                    nd -= 2;
+                    if (nd <= 0)
+                        break;
+                    b2 = pu[2];
+                    tcc->mode_telnet = 1;       /* Any such sequence activates TN */
+                    DBG("TNi: Op2 %02x %02x: %-4s %d",
+                        b1, b2, tn_cmd[b1 & 0xf], b2);
+                    _telnet_handle_opt(tcc, b2, pu + 3, nd - 1);
+                    nd += 4;
+                    goto tn_drop;
+                }
+            }
+            if (np < 16)
+                goto tn_more;   /* Not done */
+            /* This does not look right */
+            nvt_log_buf(LOG_WARNING, "tnrx", p, np);
+            rem = 0;            /* Quit loop */
+            break;
+
+        case TNC_FF_IAC:
+            p++;
+            nd = 1;             /* Drop 1 bytes */
+            goto tn_drop;
+
+          tn_drop:
+            if (!tcc->mode_telnet)
+                goto tn_break;
+            DBG2_BUF("drop", p, nd);
+            rem -= nd + (p - s);
+            len -= nd;
+            memmove(p, p + nd, rem);
+            break;
+
+          tn_break:
+            rem = 0;            /* Quit loop */
+            break;
+
+          tn_more:             /* Request more data */
+            tcc->off_rx = len - np;
+            *plen = len;
+            return 1;
+        }
+    }
+
+    tcc->off_rx = 0;
+    *plen = len;
+
+    return 0;
+}
+
+int telnet_tx(tn_ctx_t * tcc, const char *buf, int len)
+{
+    const char     *s, *p;
+    int             rem, nd;
+
+    for (s = buf, rem = len; rem > 0; s = p)
+    {
+        if (tcc->mode_telnet)
+            p = memchr(s, TNC_FF_IAC, rem);
+        else
+            p = NULL;
+        if (!p)
+        {
+            /* Send the rest */
+            nd = rem;
+            tcc->cli_tx(tcc->cctx, s, nd);
+        }
+        else
+        {
+            nd = p - s + 1;
+            tcc->cli_tx(tcc->cctx, s, nd);
+            tcc->cli_tx(tcc->cctx, p, 1);       /* One TNC_FF_IAC */
+            p++;
+        }
+        rem -= nd;
+    }
+
+    return 0;
+}
+
+tn_ctx_t       *telnet_ctx_init(void *cctx, cli_tx_f * ftx, cli_ss_f * fss)
+{
+    tn_ctx_t       *tcc;
+
+    tcc = calloc(1, sizeof(tn_ctx_t));
+    tcc->cctx = cctx;
+    tcc->cli_tx = ftx;          /* Write to client */
+    tcc->cli_ss = fss;          /* Set state (line/modem) */
+
+    telnet_rfc2217_init(tcc, TNI_INIT);
+
+    return tcc;
+}

nvtsrv/telnet_param.h

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2018 Lars Thrane A/S
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Telnet parameters
+ */
+#ifndef TELNET_PARAM_H
+#define TELNET_PARAM_H
+
+
+/*
+ * Telnet commands
+ */
+
+#define TNC_F0_SE   (0xf0)      /* End of subnegotiation parameters */
+#define TNC_F1_NOP  (0xf1)      /* No operation                     */
+#define TNC_F2_MARK (0xf2)      /* The data stream portion of a Synch.
+                                   This should always be accompanied
+                                   by a TCP Urgent notification. */
+#define TNC_F3_BRK  (0xf3)      /* NVT character BRK.               */
+#define TNC_F4_IP   (0xf4)      /* The function IP (interrupt process) */
+#define TNC_F5_AO   (0xf5)      /* The function AO (abort output)   */
+#define TNC_F6_AYT  (0xf6)      /* The function AYT (are you there) */
+#define TNC_F7_EC   (0xf7)      /* The function EC (erase charceter) */
+#define TNC_F8_EL   (0xf8)      /* The function EL (erase line)     */
+#define TNC_F9_GA   (0xf9)      /* The GA signal (go ahead)         */
+#define TNC_FA_SB   (0xfa)      /* Subnegotiation begin             */
+#define TNC_FB_WILL (0xfb)      /* Indicates the desire to begin
+                                   performing, or confirmation that
+                                   you are now performing, the
+                                   indicated option. */
+#define TNC_FC_WONT (0xfc)      /* Indicates the refusal to perform,
+                                   or continue performing, the
+                                   indicated option. */
+#define TNC_FD_DO   (0xfd)      /* Indicates the request that the
+                                   other party perform, or
+                                   confirmation that you are expecting
+                                   the other party to perform, the
+                                   indicated option. */
+#define TNC_FE_DONT (0xfe)      /* Indicates the demand that the
+                                   other party stop performing,
+                                   or confirmation that you are no
+                                   longer expecting the other party
+                                   to perform, the indicated option. */
+#define TNC_FF_IAC  (0xff)      /* Interpret as Command / data byte */
+
+
+/*
+ * Telnet options
+ */
+
+/*
+ * https://www.iana.org/assignments/telnet-options/telnet-options.xhtml
+ *
+ *   0  00  Binary Transmission                 [RFC856]
+ *   1  01  Echo                                [RFC857]
+ *   2  02  Reconnection                        [DDN Protocol Handbook, ... ]
+ *   3  03  Suppress Go Ahead                   [RFC858]
+ *   4  04  Approx Message Size Negotiation     ["The Ethernet, ..." ]
+ *   5  05  Status                              [RFC859]
+ *   6  06  Timing Mark                         [RFC860]
+ *   7  07  Remote Controlled Trans and Echo    [RFC726]
+ *   8  08  Output Line Width                   [DDN Protocol Handbook, ... ]
+ *   9  09  Output Page Size                    [DDN Protocol Handbook, ... ]
+ *  10  0a  Output Carriage-Return Disposition  [RFC652]
+ *  11  0b  Output Horizontal Tab Stops         [RFC653]
+ *  12  0c  Output Horizontal Tab Disposition   [RFC654]
+ *  13  0d  Output Formfeed Disposition         [RFC655]
+ *  14  0e  Output Vertical Tabstops            [RFC656]
+ *  15  0f  Output Vertical Tab Disposition     [RFC657]
+ *  16  10  Output Linefeed Disposition         [RFC658]
+ *  17  11  Extended ASCII                      [RFC698]
+ *  18  12  Logout                              [RFC727]
+ *  19  13  Byte Macro                          [RFC735]
+ *  20  14  Data Entry Terminal                 [RFC1043][RFC732]
+ *  21  15  SUPDUP                              [RFC736][RFC734]
+ *  22  16  SUPDUP Output                       [RFC749]
+ *  23  17  Send Location                       [RFC779]
+ *  24  18  Terminal Type                       [RFC1091]
+ *  25  19  End of Record                       [RFC885]
+ *  26  1a  TACACS User Identification          [RFC927]
+ *  27  1b  Output Marking                      [RFC933]
+ *  28  1c  Terminal Location Number            [RFC946]
+ *  29  1d  Telnet 3270 Regime                  [RFC1041]
+ *  30  1e  X.3 PAD                             [RFC1053]
+ *  31  1f  Negotiate About Window Size         [RFC1073]
+ *  32  20  Terminal Speed                      [RFC1079]
+ *  33  21  Remote Flow Control                 [RFC1372]
+ *  34  22  Linemode                            [RFC1184]
+ *  35  23  X Display Location                  [RFC1096]
+ *  36  24  Environment Option                  [RFC1408]
+ *  37  25  Authentication Option               [RFC2941]
+ *  38  26  Encryption Option                   [RFC2946]
+ *  39  27  New Environment Option              [RFC1572]
+ *  40  28  TN3270E                             [RFC2355]
+ *  41  29  XAUTH                               [Rob_Earhart]
+ *  42  2a  CHARSET                             [RFC2066]
+ *  43  2b  Telnet Remote Serial Port (RSP)     [Robert_Barnes]
+ *  44  2c  Com Port Control Option             [RFC2217]
+ *  45  2d  Telnet Suppress Local Echo          [Wirt_Atmar]
+ *  46  2e  Telnet Start TLS                    [Michael_Boe]
+ *  47  2f  KERMIT                              [RFC2840]
+ *  48  30  SEND-URL                            [David_Croft]
+ *  49  31  FORWARD_X                           [Jeffrey_Altman]
+ *  50-137  32-89  Unassigned                   [IANA]
+ * 138  8a  TELOPT PRAGMA LOGON                 [Steve_McGregory]
+ * 139  8b  TELOPT SSPI LOGON                   [Steve_McGregory]
+ * 140  8c  TELOPT PRAGMA HEARTBEAT             [Steve_McGregory]
+ * 141-254  8d-fe  Unassigned
+ * 255  ff  Extended-Options-List               [RFC861]
+*/
+
+#define TNO_BINARY   0          /* 00  Binary Transmission          */
+#define TNO_ECHO     1          /* 01  Echo                         */
+#define TNO_SUPP_GA  3          /* 03  Suppress Go Ahead            */
+#define TNO_LOGOUT  18          /* 12  Logout                       */
+#define TNO_TTYP    24          /* 18  Terminal Type                */
+#define TNO_NAWS    31          /* 1f  Negotiate About Window Size  */
+#define TNO_NEO     39          /* 27  New Environment Option       */
+#define TNO_CPCO    44          /* 2c  RFC 2217                     */
+#define TNO_KERMIT  47          /* 2f  Kermit                       */
+
+#endif /* TELNET_PARAM_H */

nvtsrv/telnet_server_rfc2217.c

@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2018 Lars Thrane A/S
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Telnet RFC-2217 handling - server
+ */
+#include <arpa/inet.h>
+
+#include "lib/nvt_log.h"
+#include "telnet.h"
+#include "telnet_param.h"
+
+void telnet_rfc2217_init(tn_ctx_t * tcc, int when)
+{
+    switch (when)
+    {
+    default:                   /* Ignore */
+        break;
+    case TNI_INIT:             /* Init context */
+        tcc->baudrate = 115200;
+        tcc->datasize = 8;      /* 8 bit */
+        tcc->parity = 1;        /* None */
+        tcc->stopsize = 1;      /* 1 bit */
+
+        tcc->linestate = 0;
+        tcc->modemstate = 0;
+
+        tcc->linestate_mask = 0;
+        tcc->modemstate_mask = 0xff;
+
+        tcc->dtr_state = 0;
+        tcc->rts_state = 0;
+        break;
+    case TNI_ON:               /* RFC-2217 activated */
+        tcc->mode_rfc2217 = 1;
+        telnet_rfc2217_change_modemstate(tcc, tcc->modemstate);
+        break;
+    }
+}
+
+
+void telnet_rfc2217_handle_opt(tn_ctx_t * tcc, int opt,
+                               unsigned char *pu, int nd)
+{
+    unsigned int    sub, vali, valo, val4;
+
+    sub = pu[0];
+    switch (sub)
+    {
+    default:
+//  case 20-127:               /* Available for Future Use */
+        nvt_log(LOG_WARNING, "Unhandled SB: Opt/prm = %d/%d", opt, sub);
+        break;
+    case 0:                    /* SIGNATURE */
+        telnet_reply_opt(tcc, opt, 100 + sub, "LT", 2);
+        DBG("RFC2217: Set signature");
+        break;
+    case 1:                    /* SET-BAUDRATE */
+        if (nd < 4)
+            break;              /* Incorrect */
+        vali = (pu[1] << 24) | (pu[2] << 16) | (pu[3] << 8) | pu[4];
+        if (vali != 0)          /* Set value */
+            tcc->baudrate = vali;
+        valo = tcc->baudrate;
+        DBG("RFC2217: Set baud %u -> %u", vali, valo);
+        val4 = htonl(valo);
+        telnet_reply_opt(tcc, opt, 100 + sub, &val4, 4);
+        break;
+    case 2:                    /* SET-DATASIZE */
+        valo = vali = pu[1];
+#if 0                           /* Request only */
+        if (vali != 0)          /* Set value */
+            tcc->datasize = vali;
+        else                    /* Request value */
+#endif
+            valo = tcc->datasize;
+        DBG("RFC2217: Set data %u -> %u", vali, valo);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    case 3:                    /* SET-PARITY */
+        valo = vali = pu[1];
+#if 0                           /* Request only */
+        if (vali != 0)          /* Set value */
+            tcc->parity = vali;
+        else
+#endif
+            valo = tcc->parity;
+        DBG("RFC2217: Set parity %u -> %u", vali, valo);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    case 4:                    /* SET-STOPSIZE */
+        valo = vali = pu[1];
+#if 0                           /* Request only */
+        if (vali != 0)          /* Set value */
+            tcc->stopsize = vali;
+        else
+#endif
+            valo = tcc->stopsize;
+        DBG("RFC2217: Set stop %u -> %u", vali, valo);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    case 5:                    /* SET-CONTROL */
+        vali = pu[1];
+        valo = 0;
+        switch (vali)
+        {
+        default:
+            nvt_log(LOG_WARNING, "Unexpected SB: Opt/prm/val = %d/%d/%u",
+                    opt, sub, vali);
+            break;
+
+        case 0:                /* Request Com Port Flow Control Setting
+                                   (outbound/both) */
+        case 1:                /* Use No Flow Control (outbound/both) */
+            valo = 1;           /* No flow control */
+            goto do_ctl_reply;
+        case 2:                /* Use XON/XOFF Flow Control (outbound/both) */
+            valo = 1;           /* No flow control */
+            nvt_log(LOG_WARNING, "RFC2217: Flow O %d -> %d", vali, valo);
+            goto do_ctl_reply;
+        case 3:                /* Use HARDWARE Flow Control (outbound/both) */
+            valo = 3;           /* HW flow control */
+            goto do_ctl_reply;
+
+        case 4:                /* Request BREAK State */
+            valo = 6;           /* BREAK off */
+            nvt_log(LOG_WARNING, "RFC2217: Break st %d -> %d", vali, valo);
+            goto do_ctl_reply;
+        case 5:                /* Set BREAK State ON */
+        case 6:                /* Set BREAK State OFF */
+            valo = 6;           /* BREAK off */
+            goto do_ctl_reply;
+
+        case 7:                /* Request DTR Signal State */
+            valo = (tcc->dtr_state) ? 8 : 9;
+            goto do_ctl_reply;
+        case 8:                /* Set DTR Signal State ON */
+        case 9:                /* Set DTR Signal State OFF */
+            valo = vali;
+            tcc->dtr_state = (valo == 8) ? 1 : 0;
+            nvt_log(LOG_INFO, "RFC2217: Set DTR %s",
+                    tcc->dtr_state ? "on" : "off");
+            goto do_ctl_reply;
+
+        case 10:               /* Request RTS Signal State */
+            valo = (tcc->rts_state) ? 11 : 12;
+            goto do_ctl_reply;
+        case 11:               /* Set RTS Signal State ON */
+        case 12:               /* Set RTS Signal State OFF */
+            valo = vali;
+            tcc->rts_state = (valo == 11) ? 1 : 0;
+            nvt_log(LOG_INFO, "RFC2217: Set RTS %s",
+                    tcc->rts_state ? "on" : "off");
+            goto do_ctl_reply;
+
+        case 13:               /* Request Com Port Flow Control Setting (inbound) */
+        case 14:               /* Use No Flow Control (inbound) */
+            valo = 14;          /* No flow control */
+            goto do_ctl_reply;
+        case 16:               /* Use HARDWARE Flow Control (inbound) */
+            valo = 16;          /* HW flow control */
+            goto do_ctl_reply;
+        case 15:               /* Use XON/XOFF Flow Control (inbound) */
+        case 17:               /* Use DCD Flow Control (outbound/both) */
+        case 18:               /* Use DTR Flow Control (inbound) */
+        case 19:               /* Use DSR Flow Control (outbound/both) */
+            valo = 14;          /* No flow control */
+            nvt_log(LOG_WARNING, "RFC2217: Flow I %d -> %d", vali, valo);
+            goto do_ctl_reply;
+
+          do_ctl_reply:
+            DBG("RFC2217: Set control %u -> %u", vali, valo);
+            telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+            switch (vali)
+            {
+            default:           /* Do noting */
+                break;
+            case 8:            /* Set DTR Signal State ON */
+            case 9:            /* Set DTR Signal State OFF */
+                if (tcc->cli_ss)
+                    tcc->cli_ss(tcc->cctx, TNS_DTR, tcc->dtr_state);
+                break;
+            case 11:           /* Set RTS Signal State ON */
+            case 12:           /* Set RTS Signal State OFF */
+                if (tcc->cli_ss)
+                    tcc->cli_ss(tcc->cctx, TNS_RTS, tcc->rts_state);
+                break;
+            }
+            break;
+        }
+        break;
+#if 0                           /* Server -> client only */
+    case 6:                    /* NOTIFY-LINESTATE */
+    case 7:                    /* NOTIFY-MODEMSTATE */
+        break;
+#endif
+    case 8:                    /* FLOWCONTROL-SUSPEND */
+    case 9:                    /* FLOWCONTROL-RESUME */
+        nvt_log(LOG_WARNING, "RFC2217: Flowcontrol %s",
+                (sub == 8) ? "suspend" : "resume");
+        /* NB! Do not reply */
+        break;
+    case 10:                   /* SET-LINESTATE-MASK */
+        valo = vali = pu[1];
+        tcc->linestate_mask = vali;
+        DBG("RFC2217: Set linestate mask 0x%02x", vali);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    case 11:                   /* SET-MODEMSTATE-MASK */
+        valo = vali = pu[1];
+        tcc->modemstate_mask = vali;
+        DBG("RFC2217: Set modemstate mask 0x%02x", vali);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    case 12:                   /* PURGE-DATA */
+        valo = vali = pu[1];
+        DBG("RFC2217: Purge %d", vali);
+        telnet_reply_opt(tcc, opt, 100 + sub, &valo, 1);
+        break;
+    }
+}
+
+void telnet_rfc2217_change_linestate(tn_ctx_t * tcc, int mask)
+{
+    unsigned char   buf[1];
+
+    if (!tcc->mode_rfc2217)
+        goto done;
+
+    buf[0] = mask & tcc->linestate_mask;
+    buf[0] &= 0xf0;             /* Drop change bits */
+    DBG("RFC2217: Notify linestate 0x%02x->0x%02x: 0x%02x",
+        tcc->linestate, mask, buf[0]);
+
+    telnet_reply_opt(tcc, TNO_CPCO, 100 + 6, buf, 1);
+
+  done:
+    tcc->linestate = mask;
+}
+
+void telnet_rfc2217_change_modemstate(tn_ctx_t * tcc, int mask)
+{
+    unsigned char   buf[1];
+
+    if (!tcc->mode_rfc2217)
+        goto done;
+
+    buf[0] = mask & tcc->modemstate_mask;
+    DBG("RFC2217: Notify modemstate 0x%02x->0x%02x: 0x%02x",
+        tcc->modemstate, mask, buf[0]);
+
+    telnet_reply_opt(tcc, TNO_CPCO, 100 + 7, buf, 1);
+
+  done:
+    tcc->modemstate = mask;
+}

nvttest/Makefile.am

@@ -0,0 +1,9 @@
+
+bin_PROGRAMS = nvttest
+
+nvttest_SOURCES = \
+	nvttest.c
+
+nvttest_CPPFLAGS = -I$(top_builddir) -I$(top_srcdir) $(CFLAGS_WARN)
+
+nvttest_LDADD = $(top_builddir)/lib/libnvt.la

nvttest/nvttest.c

@@ -0,0 +1,175 @@
+/*
+ * ttynvt stress tool
+ */
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <asm/termbits.h>
+
+#include "lib/nvt_log.h"
+
+
+#define HELP \
+    "Usage: nvttest -dqr [-n loops] [-t threads]\n"
+
+static const char *dev = "/dev/ttyNVT0";
+
+typedef struct {
+    int             nthread;
+    int             ithread;
+    int             nloop;
+    bool            opt_rand_delay;
+} topts_t;
+
+static void    *_worker(void *arg)
+{
+    topts_t        *topts = arg;
+    int             iloop;
+    int             fd, err, nw;
+    struct termios  ios;
+
+    for (iloop = 0; iloop < topts->nloop; iloop++)
+    {
+        nvt_log(LOG_INFO, "Thread %d/%d run %d/%d\n",
+                topts->ithread, topts->nthread, iloop + 1, topts->nloop);
+        {
+            fd = open(dev, O_RDWR);
+            if (fd < 0)
+            {
+                nvt_log(LOG_ERR, "Open '%s' failed: %m\n", dev);
+                break;
+            }
+
+            memset(&ios, 0, sizeof(ios));
+            err = ioctl(fd, TCGETS, &ios);
+            if (err != 0)
+            {
+                nvt_log(LOG_ERR, "ioctl(TCGETS) failed: %m\n");
+                break;
+            }
+            err = ioctl(fd, TCSETS, &ios);
+            if (err != 0)
+            {
+                nvt_log(LOG_ERR, "ioctl(TCSETS) failed: %m\n");
+                break;
+            }
+            close(fd);
+        }
+
+        {
+            int             i, len;
+            char            buf[1024];
+
+            for (i = 0; i < (int)sizeof(buf); i++)
+                buf[i] = '0' + i % 10;
+
+            fd = open(dev, O_RDWR);
+            if (fd < 0)
+            {
+                nvt_log(LOG_ERR, "Open '%s' failed: %m\n", dev);
+                break;
+            }
+
+            for (i = 0; i < 10; i++)
+            {
+                len = rand() & 0xff;
+                nw = write(fd, buf, len);
+                if (nw < 0)
+                {
+                    nvt_log(LOG_ERR, "write failed: %m\n");
+                    break;
+                }
+                if (nw < len)
+                {
+                    nvt_log(LOG_ERR, "write short: %u/%u\n", nw, len);
+                    break;
+                }
+            }
+            close(fd);
+        }
+
+        if (topts->opt_rand_delay)
+            usleep(rand() & 0xfff);
+    }
+
+    return NULL;
+}
+
+int main(int argc, char **argv)
+{
+    int             err;
+    int             opt;
+    int             ithr, nthr;
+    topts_t         topts = { }, *popts;
+    pthread_t      *ptids;
+    int             debug, quiet;
+
+    debug = quiet = 0;
+    nthr = 1;
+    topts.nloop = 1;
+
+    while ((opt = getopt(argc, argv, "dn:qrt:")) != -1)
+    {
+        switch (opt)
+        {
+        default:               /* '?' */
+            fprintf(stderr, HELP);
+            exit(EXIT_FAILURE);
+        case 'd':
+            debug += 1;
+            break;
+        case 'n':
+            topts.nloop = atoi(optarg);
+            break;
+        case 'q':
+            quiet = 1;
+            break;
+        case 'r':
+            topts.opt_rand_delay = true;
+            break;
+        case 't':
+            nthr = atoi(optarg);
+            break;
+        }
+    }
+
+    nvt_log_level(quiet, debug);
+    nvt_log_dest(NVT_LOG_STDOUT);
+
+    topts.nthread = nthr;
+
+    ptids = malloc(nthr * sizeof(pthread_t));
+
+    for (ithr = 0; ithr < nthr; ithr++)
+    {
+        nvt_log(LOG_INFO, "Create worker thread %d/%d\n", ithr + 1, nthr);
+
+        popts = malloc(sizeof(topts_t));
+        *popts = topts;
+        popts->ithread = ithr + 1;
+
+        err = pthread_create(&ptids[ithr], NULL, _worker, popts);
+        if (err)
+        {
+            nvt_log(LOG_ERR, "Failed to create thread %d/%d\n", ithr, nthr);
+            break;
+        }
+    }
+
+    for (ithr = 0; ithr < nthr; ithr++)
+    {
+        if (ptids[ithr] == 0)
+            break;
+        pthread_join(ptids[ithr], NULL);
+        nvt_log(LOG_INFO, "Joined worker thread %d/%d\n", ithr + 1, nthr);
+    }
+
+    return 0;
+}

src/Makefile.am

@@ -1,12 +1,10 @@
 
-CFLAGS_WARN = -Wall -Wextra -Werror -Wno-unused-parameter
-
 bin_PROGRAMS = ttynvt
 
 ttynvt_SOURCES = \
-	ttynvt.c nvt_log.c nvt_log.h \
-	telnet_basic.c telnet_rfc2217.c telnet.h telnet_param.h
+	ttynvt.c \
+	telnet_basic.c telnet_client_rfc2217.c telnet.h telnet_param.h
 
-ttynvt_CPPFLAGS = -I$(top_builddir) $(FUSE_CFLAGS) $(CFLAGS_WARN)
+ttynvt_CPPFLAGS = -I$(top_builddir) -I$(top_srcdir) $(FUSE_CFLAGS) $(CFLAGS_WARN)
 
-ttynvt_LDADD = $(FUSE_LIBS)
+ttynvt_LDADD = $(top_builddir)/lib/libnvt.la $(FUSE_LIBS)

src/telnet.h

@@ -2,10 +2,10 @@
  * Copyright (c) 2018 Lars Thrane A/S
  * SPDX-License-Identifier: GPL-2.0
  *
- * Telnet interface
+ * Telnet interface - client
  */
-#ifndef TELNET_H
-#define TELNET_H
+#ifndef TELNET_CLIENT_H
+#define TELNET_CLIENT_H
 
 typedef int     (srv_tx_f) (void *cctx, const void *buf, int len);
 typedef int     (srv_rx_f) (void *cctx, int timeout);
@@ -21,7 +21,7 @@ typedef struct {
 
     unsigned int    bytes_rx;   /* Rx byte count */
     unsigned int    off_rx;     /* Rx buffer offset */
-    unsigned char   mode_telnet;        /* Telnet mode */
+    signed char     mode_telnet;        /* Telnet mode */
     unsigned char   mode_rfc2217;       /* RFC-2217 mode */
     unsigned char   telnet_ack[256];    /* telnet option ack counter */
 } tn_ctx_t;
@@ -29,7 +29,7 @@ typedef struct {
 extern tn_ctx_t *telnet_ctx_init(void *cctx, srv_tx_f * ftx, srv_rx_f * frx,
                                  srv_ms_f * fss);
 
-extern int      telnet_open(tn_ctx_t * tcc);
+extern int      telnet_open(tn_ctx_t * tcc, int mode);
 
 extern int      telnet_rx(tn_ctx_t * tcc, char *buf, int *plen);
 extern int      telnet_tx(tn_ctx_t * tcc, const char *buf, int len);
@@ -44,6 +44,10 @@ extern void     telnet_rfc2217_cfg(tn_ctx_t * tcc, int cmd,
                                    const void *val, int nd);
 extern void     telnet_rfc2217_ctl(tn_ctx_t * tcc, unsigned int val);
 
+/* Telnet mode */
+#define TN_MODE_RAW         0   /* Telnet processing off */
+#define TN_MODE_TELNET      1   /* Telnet mode */
+
 /*RFC2217 modem state*/
 #define TNS_STATE_DCD    0x80
 #define TNS_STATE_RI     0x40
@@ -60,11 +64,12 @@ extern void     telnet_rfc2217_ctl(tn_ctx_t * tcc, unsigned int val);
 
 /*RFC2217 control commands*/
 #define TNS_CTL_NOFLOW      1
-#define TNS_CTL_XONOFF      2
+#define TNS_CTL_XONOFF_OUT  2
 #define TNS_CTL_CTSRTS      3
 #define TNS_CTL_DTR_ON      8
 #define TNS_CTL_DTR_OFF     9
 #define TNS_CTL_RTS_ON     11
 #define TNS_CTL_RTS_OFF    12
+#define TNS_CTL_XONOFF_IN  15
 
-#endif /*TELNET_H */
+#endif /* TELNET_CLIENT_H */

src/telnet_basic.c

@@ -2,9 +2,8 @@
  * Copyright (c) 2018 Lars Thrane A/S
  * SPDX-License-Identifier: GPL-2.0
  *
- * Telnet server - Telnet protocol handling
+ * Telnet protocol handling - client
  */
-
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
@@ -129,6 +128,10 @@ int telnet_rx(tn_ctx_t * tcc, char *buf, int *plen)
     int             np, nd;
     int             b1, b2;
 
+    /* Skip telnet processing entirely in raw mode */
+    if (tcc->mode_telnet < 0)
+        return 0;
+
     len = *plen;
     tcc->bytes_rx += len;
 
@@ -144,7 +147,7 @@ int telnet_rx(tn_ctx_t * tcc, char *buf, int *plen)
         /* We have IAC (= 0xff) */
         np = rem - (p - s);     /* N. chars available incl. IAC */
         if (np < 2)
-            return 1;
+            goto tn_more;
 
         pu = (unsigned char *)p;
         b1 = pu[1];
@@ -237,7 +240,7 @@ int telnet_tx(tn_ctx_t * tcc, const char *buf, int len)
 
     for (s = buf, rem = len; rem > 0; s = p)
     {
-        if (tcc->mode_telnet)
+        if (tcc->mode_telnet > 0)
             p = memchr(s, TNC_FF_IAC, rem);
         else
             p = NULL;
@@ -260,12 +263,18 @@ int telnet_tx(tn_ctx_t * tcc, const char *buf, int len)
     return 0;
 }
 
-int telnet_open(tn_ctx_t * tcc)
+int telnet_open(tn_ctx_t * tcc, int mode)
 {
     time_t          t = time(NULL);;
     char            buf[3];
     int             res;
 
+    if (mode == TN_MODE_RAW)
+    {
+        tcc->mode_telnet = -1;  /* Raw mode - no telnet processing */
+        return 0;
+    }
+
     buf[0] = TNC_FF_IAC;
     buf[1] = TNC_FB_WILL;
     buf[2] = TNO_CPCO;

src/telnet_client_rfc2217.c

@@ -2,11 +2,8 @@
  * Copyright (c) 2018 Lars Thrane A/S
  * SPDX-License-Identifier: GPL-2.0
  *
- * Telnet server - RFC-2217 handling
+ * Telnet RFC-2217 handling - client
  */
-
-#include <stddef.h>
-
 #include "telnet.h"
 #include "telnet_param.h"
 

src/ttynvt.c

@@ -7,7 +7,6 @@
 #include <cuse_lowlevel.h>
 #include <errno.h>
 #include <fuse_opt.h>
-#include <netdb.h>
 #include <poll.h>
 #include <pthread.h>
 #include <signal.h>
@@ -21,13 +20,12 @@
 #include <unistd.h>
 #include <asm/ioctls.h>
 #include <asm/termbits.h>
-#include <linux/sockios.h>
 #include <linux/ppp-ioctl.h>
 #include <netinet/in.h>
 #include <sys/ioctl.h>
-#include <sys/socket.h>
 
-#include "nvt_log.h"
+#include "lib/nvt_log.h"
+#include "lib/nvt_socket.h"
 #include "telnet.h"
 
 #define NET_BUF_SIZE 1024
@@ -42,12 +40,14 @@ static struct ttynvt_param {
     unsigned int    major;
     unsigned int    minor;
     const char     *dev_name;
-    char           *server;
+    const char     *server;
+    unsigned int    quiet;
     unsigned int    debug;
     int             logstd;
+    int             raw;        /* No telnet processing */
+    const char     *close_delay;
     /* Derived */
-    char            host[64];
-    unsigned int    port;
+    unsigned int    close_delay_us;
     /* Picked up */
     int             foreground;
 } ttynvt_param;
@@ -55,14 +55,17 @@ static struct ttynvt_param {
 typedef struct {
     pthread_mutex_t tty_lock;
     pthread_mutex_t poll_lock;
+    pthread_mutex_t read_lock;
+    pthread_mutex_t write_lock;
+    pthread_mutex_t ioctl_lock;
     pthread_t       ptid_poll;
     pthread_t       ptid_read;
 
     struct fuse_pollhandle *ph;
 
     volatile int    rel_pending;
-    volatile int    slave_suspended;    /*waiting for application to read data */
-    volatile int    master_suspended;   /*server is not ready to receive data */
+    volatile int    slave_suspended;    /* Waiting for application to read data */
+    volatile int    master_suspended;   /* Server is not ready to receive data */
     struct pollfd   fds[3];
 
     char            net_buf[NET_BUF_SIZE];
@@ -80,13 +83,20 @@ typedef struct {
     int             epipe;
 
     tn_ctx_t       *tn;
+
+    int             seq;
+    struct ttynvt_cli_s *cli;
 } ttynvt_t;
 
-static void _fd_close(int fd)
-{
-    if (fd >= 0)
-        close(fd);
-}
+static ttynvt_t *ptty = NULL;
+
+typedef struct ttynvt_cli_s {
+    int             id;
+    ttynvt_t       *tty;
+    struct ttynvt_cli_s *next;
+} ttynvt_cli_t;
+
+static pthread_mutex_t access_lock = PTHREAD_MUTEX_INITIALIZER;
 
 static volatile char _is_interrupted = 0;
 
@@ -117,6 +127,19 @@ static void ttynvt_interrupted(fuse_req_t req, void *data)
     pthread_kill(thread, SIGUSR2);
 }
 
+static void _ttynvt_sleep_us(unsigned int tus)
+{
+    struct timespec ts;
+
+    ts.tv_sec = tus / 1000000;
+    tus -= ts.tv_sec * 1000000;
+    ts.tv_nsec = tus * 1000;
+
+    while (nanosleep(&ts, &ts))
+        ;
+}
+
+
 static int _check_dev(void)
 {
     int             rc;
@@ -132,29 +155,10 @@ static int _check_dev(void)
     return rc;
 }
 
-
-static void ttynvt_release(fuse_req_t req, struct fuse_file_info *info)
+static void _fd_close(int fd)
 {
-    ttynvt_t       *tty = (ttynvt_t *) (uintptr_t) info->fh;
-
-    nvt_log(LOG_INFO, "connection closed\n");
-
-    tty->rel_pending = 1;
-    _fd_close(tty->fds[FD_NET].fd);
-    _fd_close(tty->fds[FD_MASTER].fd);
-    _fd_close(tty->fds[FD_SLAVE].fd);
-
-    pthread_cancel(tty->ptid_poll);
-    pthread_join(tty->ptid_poll, NULL);
-    pthread_mutex_destroy(&tty->tty_lock);
-    pthread_mutex_destroy(&tty->poll_lock);
-
-    if (tty->ph)
-        fuse_pollhandle_destroy(tty->ph);
-
-    free(tty->tn);
-    free(tty);
-    fuse_reply_err(req, 0);
+    if (fd >= 0)
+        close(fd);
 }
 
 static void _notify(ttynvt_t * tty)
@@ -238,7 +242,7 @@ static void    *_read_net(void *arg)
             }
             if (res == 0)
             {
-                nvt_log(LOG_INFO, "Connection closed by remote host\n");
+                nvt_log(LOG_NOTICE, "Connection closed by remote host\n");
                 break;
             }
             tty->net_cnt += res;
@@ -297,44 +301,6 @@ static void    *_read_net(void *arg)
     return 0;
 }
 
-static int _srv_connect(const char *host, unsigned int port)
-{
-    struct sockaddr_in serveraddr;
-    struct hostent *server;
-    int             sockfd, err;
-
-    sockfd = socket(AF_INET, SOCK_STREAM, 0);
-    if (sockfd < 0)
-    {
-        nvt_log(LOG_ERR, "Socket open failed: %m\n");
-        return sockfd;
-    }
-
-    server = gethostbyname(host);
-    if (server == NULL)
-    {
-        nvt_log(LOG_ERR, "Cannot resolve host name: %m\n");
-        close(sockfd);
-        return -1;
-    }
-
-    bzero((char *)&serveraddr, sizeof(serveraddr));
-    serveraddr.sin_family = AF_INET;
-    bcopy((char *)server->h_addr, (char *)&serveraddr.sin_addr.s_addr,
-          server->h_length);
-    serveraddr.sin_port = htons(port);
-
-    err = connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
-    if (err < 0)
-    {
-        nvt_log(LOG_ERR, "Failed to connect to: %s:%u: %m\n", host, port);
-        close(sockfd);
-        return -1;
-    }
-
-    return sockfd;
-}
-
 static int _srv_write(void *cctx, const void *buf, int len)
 {
     ttynvt_t       *tty = cctx;
@@ -418,51 +384,94 @@ static void ttynvt_init(void *userdata, struct fuse_conn_info *conn)
     set_signal_handler();
 }
 
-static void ttynvt_open(fuse_req_t req, struct fuse_file_info *info)
+static ttynvt_t *_ttynvt_ctx_create(void)
 {
     ttynvt_t       *tty;
-    char           *slave_name;
-    struct termios  ios;
-    int             sockfd;
-    int             fd;
-    int             res;
-    int             n;
+    int             i;
 
-    DBG("%s\n", __func__);
-
-    tty = calloc(1, sizeof(*tty));
+    tty = calloc(1, sizeof(ttynvt_t));
     if (!tty)
-    {
-        fuse_reply_err(req, ENOMEM);
-        return;
-    }
-    for (n = 0; n < 3; n++)
-        tty->fds[n].fd = -1;
-
-    tty->pollout = 1;
+        return NULL;
 
     tty->tn = telnet_ctx_init(tty, _srv_write, _srv_read, _modem_status_cb);
     if (!tty->tn)
     {
         free(tty);
+        return NULL;
+    }
+
+    for (i = 0; i < 3; i++)
+        tty->fds[i].fd = -1;
+
+    tty->pollout = 1;
+
+    return tty;
+}
+
+static void _ttynvt_ctx_destroy(ttynvt_t * tty)
+{
+    if (tty)
+        free(tty->tn);
+    free(tty);
+}
+
+static void ttynvt_open(fuse_req_t req, struct fuse_file_info *info)
+{
+    ttynvt_t       *tty = ptty;
+    ttynvt_cli_t   *tty_cli;
+    char           *slave_name;
+    struct termios  ios;
+    int             fd;
+    int             res;
+    int             n;
+
+
+    tty_cli = calloc(1, sizeof(ttynvt_cli_t));
+    if (!tty_cli)
+    {
         fuse_reply_err(req, ENOMEM);
         return;
     }
 
-    sockfd = _srv_connect(ttynvt_param.host, ttynvt_param.port);
-    if (sockfd < 0)
+    pthread_mutex_lock(&access_lock);
+
+    if (tty == NULL)
+        tty = _ttynvt_ctx_create();
+    if (!tty)
     {
-        free(tty->tn);
-        free(tty);
-        fuse_reply_err(req, EHOSTUNREACH);
+        fuse_reply_err(req, ENOMEM);
+        free(tty_cli);
+        pthread_mutex_unlock(&access_lock);
         return;
     }
 
-    tty->fds[FD_NET].fd = sockfd;
+    tty_cli->id = tty->seq++;
+    tty_cli->tty = tty;
+    tty_cli->next = tty->cli;
+
+    tty->cli = tty_cli;
+
+    nvt_log(LOG_INFO, "Client open (%d)\n", tty_cli->id);
+
+    if (ptty)
+        goto out;
+
+    ptty = tty;
+
+    nvt_log(LOG_INFO, "Connecting to server: %s\n", ttynvt_param.server);
+
+    fd = socket_create_client(ttynvt_param.server);
+    if (fd < 0)
+    {
+        errno = EHOSTUNREACH;
+        goto open_err;
+    }
+
+    tty->fds[FD_NET].fd = fd;
     tty->fds[FD_NET].events = POLLIN;
     tty->net_cnt = 0;
 
-    if ((fd = open("/dev/ptmx", O_RDWR)) < 0)   /* open master */
+    if ((fd = open("/dev/ptmx", O_RDWR)) < 0)   /* Open master */
         goto open_err;
 
     tty->fds[FD_MASTER].fd = fd;
@@ -480,11 +489,11 @@ static void ttynvt_open(fuse_req_t req, struct fuse_file_info *info)
     if (ioctl(fd, TCSETS, &ios) < 0)
         goto open_err;
 
-    grantpt(fd);                /* change permission of slave */
-    unlockpt(fd);               /* unlock slave */
-    slave_name = ptsname(fd);   /* get name of slave */
+    grantpt(fd);                /* Change permission of slave */
+    unlockpt(fd);               /* Unlock slave */
+    slave_name = ptsname(fd);   /* Get name of slave */
 
-    if ((fd = open(slave_name, O_RDWR | O_NOCTTY)) < 0) /* open slave */
+    if ((fd = open(slave_name, O_RDWR | O_NOCTTY)) < 0) /* Open slave */
         goto open_err;
 
     ioctl(fd, TCGETS, &tty->tio);
@@ -495,53 +504,65 @@ static void ttynvt_open(fuse_req_t req, struct fuse_file_info *info)
     tty->fds[FD_SLAVE].fd = fd;
     tty->fds[FD_SLAVE].events = POLLIN;
 
-    res = telnet_open(tty->tn);
+    res =
+        telnet_open(tty->tn, ttynvt_param.raw ? TN_MODE_RAW : TN_MODE_TELNET);
     if (res < 0)
     {
         errno = EPROTO;
         goto open_err;
     }
+
     if ((res = pthread_mutex_init(&tty->tty_lock, NULL) < 0) ||
         (res = pthread_mutex_init(&tty->poll_lock, NULL) < 0) ||
+        (res = pthread_mutex_init(&tty->ioctl_lock, NULL) < 0) ||
+        (res = pthread_mutex_init(&tty->read_lock, NULL) < 0) ||
+        (res = pthread_mutex_init(&tty->write_lock, NULL) < 0) ||
         (res = pthread_create(&tty->ptid_poll, NULL, &_read_net, tty)))
     {
         errno = res;
         goto open_err;
     }
 
-    info->fh = (uintptr_t) tty;
+    nvt_log(LOG_INFO, "Connected to server: %s\n", ttynvt_param.server);
+
+  out:
+    info->fh = (uintptr_t) tty_cli;
     info->nonseekable = 1;
     info->direct_io = 1;
 
-    nvt_log(LOG_INFO, "Connected to server: %s:%d\n",
-            ttynvt_param.host, ttynvt_param.port);
-
     fuse_reply_open(req, info);
 
+    pthread_mutex_unlock(&access_lock);
     return;
 
   open_err:
-
-    nvt_log(LOG_INFO, "Connection to server: %s:%d failed: %m\n",
-            ttynvt_param.host, ttynvt_param.port);
-
     for (n = 0; n < 3; n++)
         _fd_close(tty->fds[n].fd);
 
-    free(tty->tn);
-    free(tty);
+    free(tty_cli);
+    _ttynvt_ctx_destroy(tty);
+    ptty = NULL;
+
     fuse_reply_err(req, errno);
+
+    nvt_log(LOG_ERR, "Connection to server: %s failed: %m\n",
+            ttynvt_param.server);
+
+    pthread_mutex_unlock(&access_lock);
 }
 
 static void
 ttynvt_read(fuse_req_t req, size_t size, off_t off,
             struct fuse_file_info *info)
 {
-    ttynvt_t       *tty = (ttynvt_t *) (uintptr_t) info->fh;
+    ttynvt_cli_t   *tty_cli = (ttynvt_cli_t *) (uintptr_t) info->fh;
+    ttynvt_t       *tty = tty_cli->tty;
     char            buf[TMP_BUF_SIZE];
     int             res, nr;
 
-    DBG2("%s\n", __func__);
+    pthread_mutex_lock(&tty->read_lock);
+
+    DBG2("%s (%d)\n", __func__, tty_cli->id);
 
     if (tty->error)
     {
@@ -555,7 +576,7 @@ ttynvt_read(fuse_req_t req, size_t size, off_t off,
         else
             fuse_reply_err(req, EBADFD);
 
-        return;
+        goto out;
     }
 
     if (size > TMP_BUF_SIZE)
@@ -582,36 +603,42 @@ ttynvt_read(fuse_req_t req, size_t size, off_t off,
     {
         DBG2("%s: error: %m\n", __func__);
         fuse_reply_err(req, errno);
-        return;
+        goto out;
     }
 
-    DBG2("%s: fd=%d: sz=%u/%u: '%.*s'\n", __func__,
-         tty->fds[FD_SLAVE].fd, res, (int)size, res, buf);
+    DBG2("%s (%d): fd=%d: sz=%u/%u: '%.*s'\n", __func__,
+         tty_cli->id, tty->fds[FD_SLAVE].fd, res, (int)size, res, buf);
 
     fuse_reply_buf(req, buf, res);
+
+  out:
+    pthread_mutex_unlock(&tty->read_lock);
 }
 
 static void
 ttynvt_write(fuse_req_t req, const char *data, size_t size, off_t off,
              struct fuse_file_info *info)
 {
-    ttynvt_t       *tty = (ttynvt_t *) (uintptr_t) info->fh;
+    ttynvt_cli_t   *tty_cli = (ttynvt_cli_t *) (uintptr_t) info->fh;
+    ttynvt_t       *tty = tty_cli->tty;
     int             res;
 
-    DBG2("%s: fd=%d: sz=%u: '%.*s'\n", __func__,
-         tty->fds[FD_SLAVE].fd, (int)size, (int)size, data);
+    pthread_mutex_lock(&tty->write_lock);
+
+    DBG2("%s (%d): fd=%d: sz=%u: '%.*s'\n", __func__,
+         tty_cli->id, tty->fds[FD_SLAVE].fd, (int)size, (int)size, data);
 
     if (size == 0)
     {
         fuse_reply_write(req, 0);
-        return;
+        goto out;
     }
 
     if (tty->error)
     {
         DBG2("%s: tty->error=%d\n", __func__, tty->error);
         fuse_reply_err(req, EPIPE);
-        return;
+        goto out;
     }
 
     res = write(tty->fds[FD_SLAVE].fd, data, size);
@@ -620,7 +647,7 @@ ttynvt_write(fuse_req_t req, const char *data, size_t size, off_t off,
         DBG2("%s: error: %m\n", __func__);
         tty->error = 1;
         fuse_reply_err(req, errno);
-        return;
+        goto out;
     }
     else if (res != (int)size)
     {
@@ -629,6 +656,9 @@ ttynvt_write(fuse_req_t req, const char *data, size_t size, off_t off,
     }
 
     fuse_reply_write(req, res);
+
+  out:
+    pthread_mutex_unlock(&tty->write_lock);
 }
 
 static int baudrate(speed_t speed)
@@ -717,10 +747,10 @@ static unsigned int _tio_parity(const struct termios2 *tio)
 {
     unsigned int    par;
 
-    if (tio->c_cflag & PARENB && tio->c_iflag & IGNPAR)
+    if ((tio->c_cflag & PARENB) && (tio->c_iflag & IGNPAR))
         par = 1;
 #ifdef CMSPAR
-    else if (tio->c_cflag & PARENB && tio->c_iflag & CMSPAR)
+    else if ((tio->c_cflag & PARENB) && (tio->c_iflag & CMSPAR))
     {
         if (tio->c_cflag & PARODD)
             par = 4;
@@ -806,7 +836,8 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
              struct fuse_file_info *info, unsigned int flags,
              const void *in_buf, size_t in_bufsz, size_t out_bufsz)
 {
-    ttynvt_t       *tty = (ttynvt_t *) (uintptr_t) info->fh;
+    ttynvt_cli_t   *tty_cli = (ttynvt_cli_t *) (uintptr_t) info->fh;
+    ttynvt_t       *tty = tty_cli->tty;
     struct termios2 *tio = &tty->tio;
     struct winsize  ws;
     unsigned int    tiocm, baud;
@@ -816,10 +847,18 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
     uint8_t         byte;
     uint32_t        byte4;
 
-    DBG("%s: cmd=%s arg=%p ibuf=%p:%u obuf=:%u\n", __func__,
-        _ioctl_name(cmd), arg, in_buf,
+    pthread_mutex_lock(&tty->ioctl_lock);
+
+    DBG("%s (%d): cmd=%s arg=%p ibuf=%p:%u obuf=:%u\n", __func__,
+        tty_cli->id, _ioctl_name(cmd), arg, in_buf,
         (unsigned int)in_bufsz, (unsigned int)out_bufsz);
 
+    if (ttynvt_param.raw)
+    {
+        fuse_reply_ioctl(req, 0, 0, 0);
+        goto out;
+    }
+
     switch (cmd)
     {
     case TCSETSF:
@@ -855,6 +894,14 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
             tty->master_suspended = (tty->smcr & TIOCM_CTS) ? 0 : 1;
             telnet_rfc2217_ctl(tty->tn, TNS_CTL_CTSRTS);
         }
+        else if (tio->c_iflag & (IXON | IXOFF))
+        {
+            tty->master_suspended = 0;
+            if (tio->c_iflag & IXON)
+                telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_OUT);
+            if (tio->c_iflag & IXOFF)
+                telnet_rfc2217_ctl(tty->tn, TNS_CTL_XONOFF_IN);
+        }
         else
         {
             tty->master_suspended = 0;
@@ -918,6 +965,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         case TCIFLUSH:
             byte = 1;
             tty->slave_suspended = 0;   /* Re-enable polling of Slave */
+            tty->pollin = 0;
             break;
         case TCOFLUSH:
             byte = 2;
@@ -927,6 +975,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
             byte = 3;
             tty->slave_suspended = 0;   /* Re-enable polling of Slave */
             tty->pollout = 1;
+            tty->pollin = 0;
             break;
         }
         telnet_rfc2217_cfg(tty->tn, TNS_SET_PURGE, &byte, 1);
@@ -942,7 +991,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         break;
     case TIOCMBIS:
         CHECK_BUF_IN(sizeof(int));
-        tiocm = *(unsigned int *)in_buf;
+        tiocm = *(const unsigned int *)in_buf;
         fuse_reply_ioctl(req, 0, 0, 0);
         DBG("%s: cmd=%s tiocm=%#x\n", __func__, _ioctl_name(cmd), tiocm);
         if (tiocm & TIOCM_RTS)
@@ -958,7 +1007,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         goto show_mctl;
     case TIOCMBIC:
         CHECK_BUF_IN(sizeof(int));
-        tiocm = *(unsigned int *)in_buf;
+        tiocm = *(const unsigned int *)in_buf;
         fuse_reply_ioctl(req, 0, 0, 0);
         DBG("%s: cmd=%s tiocm=%#x\n", __func__, _ioctl_name(cmd), tiocm);
         if (tiocm & TIOCM_RTS)
@@ -974,7 +1023,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         goto show_mctl;
     case TIOCMSET:
         CHECK_BUF_IN(sizeof(int));
-        tiocm = *(unsigned int *)in_buf;
+        tiocm = *(const unsigned int *)in_buf;
         fuse_reply_ioctl(req, 0, 0, 0);
         DBG("%s: cmd=%s tiocm=%#x\n", __func__, _ioctl_name(cmd), tiocm);
         tty->cmcr &= ~(TIOCM_RTS | TIOCM_DTR);
@@ -998,18 +1047,18 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         if (res < 0)
         {
             fuse_reply_err(req, errno);
-            return;
+            goto out;
         }
         fuse_reply_ioctl(req, 0, &ws, sizeof(struct winsize));
         break;
     case TIOCSWINSZ:
         CHECK_BUF_IN(sizeof(struct winsize));
-        ws = *(struct winsize *)in_buf;
+        ws = *(const struct winsize *)in_buf;
         res = ioctl(tty->fds[FD_SLAVE].fd, TIOCSWINSZ, &ws);
         if (res < 0)
         {
             fuse_reply_err(req, errno);
-            return;
+            goto out;
         }
         fuse_reply_ioctl(req, 0, &ws, sizeof(struct winsize));
         break;
@@ -1028,7 +1077,7 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         break;
     case TIOCSETD:
         CHECK_BUF_IN(sizeof(int));
-        val = *(int *)in_buf;
+        val = *(const int *)in_buf;
         res = ioctl(tty->fds[FD_SLAVE].fd, TIOCSETD, &val);
         if (res < 0)
             fuse_reply_err(req, errno);
@@ -1070,17 +1119,21 @@ ttynvt_ioctl(fuse_req_t req, int cmd, void *arg,
         }
         break;
     }
+
+  out:
+    pthread_mutex_unlock(&tty->ioctl_lock);
 }
 
 static void
 ttynvt_poll(fuse_req_t req, struct fuse_file_info *info,
             struct fuse_pollhandle *ph)
 {
-    ttynvt_t       *tty = (ttynvt_t *) (uintptr_t) info->fh;
+    ttynvt_cli_t   *tty_cli = (ttynvt_cli_t *) (uintptr_t) info->fh;
+    ttynvt_t       *tty = tty_cli->tty;
     int             revents = 0;
 
-    DBG2("%s: tty->pollin=%d tty->error/epipe=%d/%d\n",
-         __func__, tty->pollin, tty->error, tty->epipe);
+    DBG2("%s (%d): tty->pollin=%d tty->error/epipe=%d/%d\n",
+         __func__, tty_cli->id, tty->pollin, tty->error, tty->epipe);
 
     _update_notify(tty, ph);
 
@@ -1105,6 +1158,62 @@ ttynvt_poll(fuse_req_t req, struct fuse_file_info *info,
     fuse_reply_poll(req, revents);
 }
 
+static void ttynvt_release(fuse_req_t req, struct fuse_file_info *info)
+{
+    ttynvt_cli_t   *tty_cli = (ttynvt_cli_t *) (uintptr_t) info->fh;
+    ttynvt_t       *tty = tty_cli->tty;
+    ttynvt_cli_t   *tmp, *prev;
+
+    DBG("%s\n", __func__);
+
+    pthread_mutex_lock(&access_lock);
+
+    for (tmp = tty->cli, prev = NULL; tmp; prev = tmp, tmp = tmp->next)
+        if (tmp == tty_cli)
+        {
+            nvt_log(LOG_INFO, "Client release (%d)\n", tmp->id);
+            if (prev)
+                prev->next = tmp->next;
+            else
+                tty->cli = tmp->next;
+            free(tmp);
+            break;
+        }
+
+    if (tty->cli)
+        goto out;
+
+    tty->rel_pending = 1;
+
+    pthread_cancel(tty->ptid_poll);
+    pthread_join(tty->ptid_poll, NULL);
+    pthread_mutex_destroy(&tty->tty_lock);
+    pthread_mutex_destroy(&tty->poll_lock);
+    pthread_mutex_destroy(&tty->ioctl_lock);
+    pthread_mutex_destroy(&tty->read_lock);
+    pthread_mutex_destroy(&tty->write_lock);
+
+    if (ttynvt_param.close_delay_us)
+        _ttynvt_sleep_us(ttynvt_param.close_delay_us);
+
+    _fd_close(tty->fds[FD_NET].fd);
+    _fd_close(tty->fds[FD_MASTER].fd);
+    _fd_close(tty->fds[FD_SLAVE].fd);
+
+    if (tty->ph)
+        fuse_pollhandle_destroy(tty->ph);
+
+    _ttynvt_ctx_destroy(tty);
+    ptty = NULL;
+
+    nvt_log(LOG_INFO, "Disconnected from server: %s\n", ttynvt_param.server);
+
+  out:
+    fuse_reply_err(req, 0);
+
+    pthread_mutex_unlock(&access_lock);
+}
+
 static const struct cuse_lowlevel_ops ttynvt_op = {
     .init = ttynvt_init,
     .open = ttynvt_open,
@@ -1126,6 +1235,9 @@ static const struct fuse_opt ttynvt_opts[] = {
     TTYNET_OPT("--min=%u", minor, 1),
     TTYNET_OPT("-n %s", dev_name, 0),
     TTYNET_OPT("--name=%s", dev_name, 0),
+    TTYNET_OPT("-q", quiet, 1),
+    TTYNET_OPT("-r", raw, 1),
+    TTYNET_OPT("-s %s", close_delay, 0),
     TTYNET_OPT("-S %s", server, 0),
     TTYNET_OPT("--server=%s", server, 0),
     FUSE_OPT_KEY("-h", 0),
@@ -1139,11 +1251,14 @@ static void print_help(void)
             "\t-D level\tEnable debug\n"
             "\t-d\t\tStay in foreground, do not detach\n"
             "\t-f\t\tStay in foreground, do not detach\n"
-            "\t-E\t\tPrint debug to stdout (default is syslog)\n"
+            "\t-E\t\tPrint debug to stderr (default is syslog)\n"
             "\t-M major, --maj=major\n"
             "\t-m minor, --min=minor\n"
             "\t-n name, --name=name (default: ttyNVT0)\n"
             "\t\tDevice will be created in /dev/$name.\n"
+            "\t-q\t\tBe quiet (suppress informational messages)\n"
+            "\t-r\t\tDisable telnet processing\n"
+            "\t-s delay \t\tDelay at close in ms (use u suffix for us)\n"
             "\t-S server, --server=host:port\n");
 }
 
@@ -1179,8 +1294,9 @@ int main(int argc, char *argv[])
         return 1;
     }
 
-    log_level = ttynvt_param.debug;
-    log_stdout = ttynvt_param.logstd;
+    nvt_log_level(ttynvt_param.quiet, ttynvt_param.debug);
+    if (ttynvt_param.logstd)
+        nvt_log_dest(NVT_LOG_STDERR);
 
     if (!ttynvt_param.dev_name)
         ttynvt_param.dev_name = "ttyNVT0";
@@ -1191,22 +1307,18 @@ int main(int argc, char *argv[])
         return 1;
     }
 
-    rc = sscanf(ttynvt_param.server, "%63[^:]:%u", ttynvt_param.host,
-                &ttynvt_param.port);
-    if (rc <= 1)
-    {
-        fprintf(stderr, "Bad server specification: '%s'\n",
-                ttynvt_param.server);
-        return 1;
-    }
-    if (ttynvt_param.port == 0)
-    {
-        fprintf(stderr, "Bad server port: %u\n", ttynvt_param.port);
-        return 1;
-    }
-
     snprintf(dev_name, sizeof(dev_name), "DEVNAME=%s", ttynvt_param.dev_name);
 
+    if (ttynvt_param.close_delay)
+    {
+        char            ch = 'm';
+
+        sscanf(ttynvt_param.close_delay, "%u%c",
+               &ttynvt_param.close_delay_us, &ch);
+        if (ch != 'u')
+            ttynvt_param.close_delay_us *= 1000;        // To milliseconds
+    }
+
     struct cuse_info ci = {
         .dev_major = ttynvt_param.major,
         .dev_minor = ttynvt_param.minor,