Tag Docker images with `latest` tag

* Logging fix and enhancement

Corrected issue where loglevel in mbusd.conf wasn't parsed correctly. Added support for logfile in mbusd.conf.  Updated README and mbusd..conf.example to true-up with "-h" output and new logging options.

* Updated README

Sync'd up verbiage in the usage details with the usage summary.

* Additional adjustments to sync up README w/ -h output

.github/stale.yml

@@ -0,0 +1,17 @@
+# Number of days of inactivity before an issue becomes stale
+daysUntilStale: 120
+# Number of days of inactivity before a stale issue is closed
+daysUntilClose: 30
+# Issues with these labels will never be considered stale
+exemptLabels:
+  - 'Good first issue'
+  - enhancement
+# Label to use when marking an issue as stale
+staleLabel: stale
+# Comment to post when marking an issue as stale. Set to `false` to disable
+markComment: >
+  This issue has been automatically marked as stale because it has not had
+  recent activity. It will be closed if no further activity occurs. Thank you
+  for your contributions.
+# Comment to post when closing a stale issue. Set to `false` to disable
+closeComment: false

.github/workflows/build.yml

@@ -0,0 +1,44 @@
+name: build
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+ BUILD_TYPE: Release
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: '3.x'
+            
+    - name: Configure CMake
+      # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
+      # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      # Build your program with the given configuration
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
+
+    - name: Install test dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install setuptools wheel twisted pyserial pymodbus
+        sudo apt-get install -y socat
+
+    - name: Run tests
+      working-directory: ${{github.workspace}}/build
+      run: make test
+      
+    - name: Show failed test log
+      if: ${{ failure() }}
+      run: cat ${{github.workspace}}/build/Testing/Temporary/LastTest.log

.github/workflows/docker-publish.yml

@@ -0,0 +1,63 @@
+name: docker publish
+
+on:
+  push:
+    tags: [ 'v[0-9].[0-9]+.[0-9]+' ]
+  workflow_run:
+    workflows: [ 'build' ]
+    types: [ completed ]
+    branches: [ 'master' ]
+
+env:
+  PLATFORMS: linux/amd64,linux/arm64,linux/arm/v7
+  # github.repository as <account>/<repo>
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Docker Hub
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      # Extract metadata (tags, labels) for Docker
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.IMAGE_NAME }}
+          tags: |
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=sha
+
+      # Build and push Docker image with Buildx (don't push on PR)
+      # https://github.com/docker/build-push-action
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          platforms: ${{ env.PLATFORMS }}
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha,scope=${{ env.IMAGE_NAME }}
+          cache-to: type=gha,mode=max,scope=${{ env.IMAGE_NAME }}

.gitignore

@@ -1,25 +1,11 @@
-/autom4te.cache
-/config.cache
-/config.h
-/config.status
-/.settings/
-/src/.deps/
-/src/*.o
-/src/mbusd
-/doc/mbusd.8
-Makefile
+/.settings
 *.log
-*.in~
-systemd-units/mbusd@.service
 *.conf
 *.pyc
-CMakeCache.txt
-CMakeFiles
-CPackConfig.cmake
-CPackSourceConfig.cmake
-cmake_install.cmake
-.idea
-*~
+/.idea
+/.vscode
 .project
 .cproject
-build
+.pydevproject
+/build
+build.sh

.travis.yml

@@ -1,18 +0,0 @@
-sudo: required
-
-dist: trusty
-
-language: c
-
-compiler:
-  - gcc
-  - clang
-
-before_install:
-  - sudo apt-get update -qq
-
-script:
-  - mkdir build
-  - cd build
-  - cmake ..
-  - make

CHANGELOG.md

@@ -1,4 +1,31 @@
-# Change Log
+# Changelog
+
+## [0.5.2] - 2024-03-27
+- Make use of Linux RS-485 support (#97).
+- Add flag `-r` to support inverted RTS flow control(#98).
+- Logging fixes and enhancements (#90).
+- Default log file name changed to `/var/log/mbusd.log`.
+- Fix building on older gcc versions (#100).
+- Add docker image publish github workflow.
+
+## [0.5.1] - 2022-08-18
+- Add 'reply on broadcast' feature (#75).
+- Fix for "Resource temporarily unavailable" error in tty read() (#78).
+- Add simple Dockerfile for running mbusd containerized (#79).
+- Add support for more complex serial port device names (#81).
+- Do not segfault when closing last connection (#83).
+- Fix crash due to missing logw() argument (#84).
+## [0.5.0] - 2020-11-28
+### Added
+- Command-line and config options to set an TCP socket address (#53).
+- IPv6 support (#53).
+- Support for RTU broadcast messages (#61).
+- More baudrates (#62).
+
+### Fixed
+- Added online network requirements to the systemd service file (#58).
+- Take into account tty parity bit in the timing calculations (#59).
+- Show an error when trying to use unsupported baudrate (#63).
 
 ## [0.4.0] - 2019-07-08
 ### Added
@@ -61,7 +88,11 @@
 ## 0.1.1 - 2003-09-13
 ### Initial release
 
+[0.5.2]: https://github.com/3cky/mbusd/compare/v0.5.1...v0.5.2
+[0.5.1]: https://github.com/3cky/mbusd/compare/v0.5.0...v0.5.1
+[0.5.0]: https://github.com/3cky/mbusd/compare/v0.4.0...v0.5.0
 [0.4.0]: https://github.com/3cky/mbusd/compare/v0.3.0...v0.4.0
 [0.3.0]: https://github.com/3cky/mbusd/compare/v0.2.3...v0.3.0
 [0.2.3]: https://github.com/3cky/mbusd/compare/v0.2.2...v0.2.3
-[0.2.2]: https://github.com/3cky/mbusd/compare/v0.2.1...v0.2.2
+[0.2.2]: https://github.com/3cky/mbusd/compare/v0.2.1...v0.2.2
+

CMakeLists.txt

@@ -1,10 +1,11 @@
 cmake_minimum_required(VERSION 3.2)
 
-project(mbusd VERSION 0.4.0)
+project(mbusd VERSION 0.5.2)
 
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/extern_GPL)
 include(CheckFunctionExists)
 include(CheckLibraryExists)
+include(CheckSymbolExists)
 include(GNUInstallDirs)
 include(FindUnixCommands)
 include(FindSystemd)
@@ -41,6 +42,10 @@ check_function_exists(cfsetispeed HAVE_CFSETISPEED)
 if(HAVE_CFSETSPEED AND HAVE_CFSETISPEED)
     add_definitions(-DHAVE_CFSETSPEED)
 endif()
+check_symbol_exists(TIOCSRS485 sys/ioctl.h HAVE_TIOCRS485)
+if(HAVE_TIOCRS485)
+    add_definitions(-DHAVE_TIOCRS485)
+endif()
 check_function_exists(time HAVE_TIME)
 check_function_exists(localtime HAVE_LOCALTIME)
 if(HAVE_TIME AND HAVE_LOCALTIME)
@@ -65,10 +70,10 @@ set(mbusd_SOURCES
         src/conn.c
         src/queue.c
         src/modbus.c
-        src/crc16.c
         src/state.c
         src/sig.c
         src/sock.c
+        src/util.c
         )
 add_executable(mbusd ${mbusd_SOURCES})
 install(TARGETS mbusd DESTINATION bin)

Dockerfile

@@ -0,0 +1,10 @@
+FROM --platform=$BUILDPLATFORM alpine:latest AS build
+RUN apk add --no-cache alpine-sdk cmake linux-headers
+COPY . /mbusd
+WORKDIR /mbusd/build
+RUN cmake -DCMAKE_INSTALL_PREFIX=/usr .. && make && make install
+
+FROM alpine:latest AS scratch
+ENV QEMU_EXECVE=1
+COPY --from=build /usr/bin/mbusd /usr/bin/mbusd
+ENTRYPOINT ["/usr/bin/mbusd", "-d", "-L", "-", "-c", "/etc/mbusd.conf"]

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2002-2003, 2013-2019 Victor Antonovich (v.antonovich@gmail.com)
+Copyright (c) 2002-2003, 2013-2024 Victor Antonovich (v.antonovich@gmail.com)
 Copyright (c) 2011 Andrew Denysenko <nitr0@seti.kr.ua>
 All rights reserved.
 

README.md

@@ -1,7 +1,7 @@
 About mbusd
 ===========
 
-[![Build Status](https://travis-ci.org/3cky/mbusd.svg?branch=master)](https://travis-ci.org/3cky/mbusd)
+[![mbusd](https://github.com/3cky/mbusd/actions/workflows/build.yml/badge.svg)](https://github.com/3cky/mbusd/actions/workflows/build.yml)
 
 **mbusd** is open-source [Modbus TCP to Modbus RTU (RS-232/485)](https://en.wikipedia.org/wiki/Modbus)
 gateway. It presents a network of RTU slaves as single TCP slave.
@@ -52,19 +52,21 @@ can be altered in many ways, e.g. by using the following tools in the `build` di
 Usage:
 ------
 
-       mbusd [-h] [-d] [-L logfile] [-v level] [-c cfgfile] [-p device] [-s speed] [-m mode]
-       		[-t] [-y file] [-Y file] [-P port] [-C maxconn] [-N retries]
-       		[-R pause] [-W wait] [-T timeout]
+       mbusd [-h] [-d] [-L logfile] [-v level] [-c cfgfile] 
+             [-p device] [-s speed] [-m mode] [-S]
+             [-t] [-r] [-y sysfsfile] [-Y sysfsfile] 
+             [-A address] [-P port] [-C maxconn] [-N retries]
+             [-R pause] [-W wait] [-T timeout] [-b]
 
        -h     Usage help.
        -d     Instruct mbusd not to fork itself (non-daemonize).
        -L logfile
-              Specifies log file name ('-' for logging to STDOUT only, default is /var/log/mbusd.log).
+              Specifies log file name ('-' for logging to STDOUT only, relative path or bare filename
+              will be stored at /var/log, default is /var/log/mbusd.log).
        -v level
-              Specifies  log  verbosity level (0 for errors only, 1 for warnings
-              and 2 for also information messages.) If mbusd was compiled in debug mode,
-              valid log levels are up to 9, where log levels above 2 forces
-              logging of information about additional internal events.
+              Specifies log verbosity level (0 for errors only, 1 for warnings and 2 for informational 
+              messages also). If mbusd was compiled in debug mode, valid log levels are up to 9, 
+              where log levels above 2 adds logging of information about additional internal events.
        -c cfgfile
               Read configuration from cfgfile.
        -p device
@@ -73,25 +75,31 @@ Usage:
               Specifies serial port speed.
        -m mode
               Specifies serial port mode (like 8N1).
-       -t     Enable RTS RS-485 data direction control (if not disabled while compile).
-       -y file
-              Enable RS-485 direction data direction control by writing '1' to file
-              for transmitter enable and '0' to file for transmitter disable
-       -Y file
-              Enable RS-485 direction data direction control by writing '0' to file
-              for transmitter enable and '1' to file for transmitter disable
+       -S     Enable RS-485 support for given serial port device (Linux only)
+       -t     Enable RTS RS-485 data direction control using RTS, active transmit.
+       -r     Enable RTS RS-485 data direction control using RTS, active receive.
+       -y sysfsfile
+              Enable RS-485 direction data direction control by writing '1' to sysfs file
+              for transmitter enable and '0' to file for transmitter disable.
+       -Y sysfsfile
+              Enable RS-485 direction data direction control by writing '0' to sysfs file
+              for transmitter enable and '1' to file for transmitter disable.
+       -A address
+             Specifies TCP server address to bind (default is 0.0.0.0).
        -P port
-              Specifies TCP port number (default 502).
+              Specifies TCP server port number (default is 502).
        -C maxconn
-              Specifies maximum number of simultaneous TCP connections.
+              Specifies maximum number of simultaneous TCP connections (default is 32).
        -N retries
-              Specifies maximum number of request retries (0 disables retries).
+              Specifies maximum number of request retries (0 disables retries, default is 3).
        -R pause
-              Specifies pause between requests in milliseconds.
+              Specifies pause between requests in milliseconds (default is 100ms).
        -W wait
-              Specifies response wait time in milliseconds.
+              Specifies response wait time in milliseconds (default is 500ms).
        -T timeout
-              Specifies connection timeout value in seconds (0 disables timeout).
+              Specifies connection timeout value in seconds (0 disables timeout, default is 60).
+       -b
+              Instructs mbusd to reply on a broadcast.
 
 Please note running **mbusd** on default Modbus TCP port (502) requires root privileges!
 
@@ -112,7 +120,7 @@ The **mbusd** service can be started via:
 
 	# systemctl start mbusd@<serial port>.service
 
-where `<serial port>` is serial port device name (like `ttyUSB0`).
+where `<serial port>` is escaped serial port device short name (like `ttyUSB0` for `/dev/ttyUSB0` device name or `serial-rs485` for `/dev/serial/rs485` device name).
 
 **mbusd** started by systemd will read its configuration from file named `/etc/mbusd/mbusd-<serial port>.conf`.
 This way it's possible to run multiple **mbusd** instances with different configurations.
@@ -129,7 +137,23 @@ To start the **mbusd** service on system boot:
 
 	# systemctl enable mbusd@<serial port>.service
 
-Please check systemd documentation for other usefull systemd [commands](https://wiki.archlinux.org/index.php/systemd)
+Please check systemd documentation for other usefull systemd [commands](https://wiki.archlinux.org/index.php/systemd).
+
+Docker:
+-------
+
+**mbusd** can be launched in Docker container with the following command:
+
+```shell
+docker run -d --privileged \
+    --name=mbusd \
+    -p 502:502 \
+    -v /dev:/dev \
+    -v /path/to/mbusd.conf:/etc/mbusd.conf \
+    3cky/mbusd:latest
+```
+
+where `/path/to/mbusd.conf` is the path to **mbusd** config file in the local filesystem.
 
 Contributing:
 -------------

conf/mbusd.conf.example

@@ -4,6 +4,14 @@
 #                                           #
 #############################################
 
+########## Logging settings #############
+
+# Logging verbosity level
+loglevel = 2
+
+# Logfile (fully-qualified path, or filename [stored at /var/log/] or - for STDOUT only)
+logfile = /var/log/mbusd.log
+
 ########## Serial port settings #############
 
 # Serial port device name
@@ -15,7 +23,10 @@ speed = 9600
 # Serial port mode
 mode = 8n1
 
-# RS-485 data direction control type (addc, rts, sysfs_0, sysfs_1)
+# Enable RS-485 support for given serial port device (Linux only)
+# enable_rs485 = no
+
+# RS-485 data direction control type (addc, rts_0, rts/rts_1, sysfs_0, sysfs_1)
 trx_control = addc
 
 # Sysfs file to use to control data direction
@@ -23,6 +34,9 @@ trx_control = addc
 
 ############# TCP port settings #############
 
+# TCP server address to bind
+address = 0.0.0.0
+
 # TCP server port number
 port = 502
 
@@ -42,3 +56,6 @@ pause = 100
 
 # Response wait time in milliseconds
 wait = 500
+
+# Reply on Broadcast
+replyonbroadcast = no

doc/mbusd.8.in

@@ -1,4 +1,4 @@
-.TH "mbusd" 8 "8 Jul 2019" "mbusd @PROJECT_VERSION@"
+.TH "mbusd" 8 "27 Mar 2024" "mbusd @PROJECT_VERSION@"
 .SH NAME
 mbusd \- MODBUS/TCP to MODBUS/RTU gateway.
 .SH SYNOPSIS
@@ -18,10 +18,13 @@ mbusd \- MODBUS/TCP to MODBUS/RTU gateway.
 .RB [ -m
 .IR mode ]
 .RB [ -t ]
+.RB [ -r ]
 .RB [ -y
-.IR file ]
+.IR sysfsfile ]
 .RB [ -Y
-.IR file ]
+.IR sysfsfile ]
+.RB [ -A
+.IR address ]
 .RB [ -P
 .IR port ]
 .RB [ -C
@@ -34,6 +37,7 @@ mbusd \- MODBUS/TCP to MODBUS/RTU gateway.
 .IR wait ]
 .RB [ -T
 .IR timeout ]
+.RB [ -b ]
 .SH DESCRIPTION
 \fImbusd\fR is MODBUS/TCP to MODBUS/RTU gateway.
 .SH OPTIONS
@@ -57,16 +61,22 @@ Specifies serial port device name.
 Specifies serial port speed.
 .IP "\fB-m \fImode\fR"
 Specifies serial port mode (like 8N1).
+.IP \fB-S\fR
+Enable RS-485 support for given serial port device (Linux only).
+.IP "\fB-A \fIaddress\fR"
+Specifies TCP address to bind.
 .IP "\fB-P \fIport\fR"
 Specifies TCP port number.
 .IP \fB-t\fR
-Enable RTS RS-485 data direction control (if not disabled while compile).
+Enable RTS RS-485 data direction control using RTS, active transmit.
+.IP \fB-r\fR
+Enable RTS RS-485 data direction control using RTS, active receive.
 .IP "\fB-y \fIfile\fR"
 Enable RS-485 direction data direction control by writing '1' to file
-for transmitter enable and '0' to file for transmitter disable
+for transmitter enable and '0' to file for transmitter disable.
 .IP "\fB-Y \fIfile\fR"
 Enable RS-485 direction data direction control by writing '0' to file
-for transmitter enable and '1' to file for transmitter disable
+for transmitter enable and '1' to file for transmitter disable.
 .IP "\fB-C \fImaxconn\fR"
 Specifies maximum number of simultaneous TCP connections.
 .IP "\fB-N \fIretries\fR"
@@ -77,14 +87,14 @@ Specifies pause between requests in milliseconds.
 Specifies response wait time in milliseconds.
 .IP "\fB-T \fItimeout\fR"
 Specifies connection timeout value in seconds (0 - disable timeout).
+.IP "\fB-b\fR"
+Instructs \fImbusd\fR to reply on a broadcast.
 .SH NOTES
 In case of situation when \fImbusd\fR received response with invalid CRC and can't correct
 error by re-request, it return MODBUS/TCP packet with exception code 04. In case of situation
 when \fImbusd\fR can't receive response from MODBUS RTU device (e.g. addressed controller
 is not present on the network), it return MODBUS/TCP packet with exception code 0x0B.
 .SH BUGS
-Broadcast messaging on MODBUS network isn't supported.
-
 Please send bug reports to author.
 .SH AUTHORS
 Victor Antonovich <v.antonovich@gmail.com>

src/cfg.c

@@ -34,13 +34,15 @@
 #include "cfg.h"
 
 #include <stdlib.h>
-#include <ctype.h>
 #include <string.h>
 
+#include "util.h"
+
 #define CFG_MAX_LINE_LENGTH 200
 
 #define CFG_NAME_MATCH(n) strcmp(n, name) == 0
 #define CFG_VALUE_MATCH(n) strcasecmp(n, value) == 0
+#define CFG_VALUE_BOOL() (strcasecmp("y", value) == 0 || strcasecmp("yes", value) == 0)
 
 /* Global configuration storage variable */
 cfg_t cfg;
@@ -63,34 +65,21 @@ cfg_init(void)
   strncpy(cfg.ttyport, DEFAULT_PORT, INTBUFSIZE);
   cfg.ttyspeed = DEFAULT_SPEED;
   strncpy(cfg.ttymode, DEFAULT_MODE, INTBUFSIZE);
+#ifdef HAVE_TIOCRS485
+  cfg.rs485 = FALSE;
+#endif  
 #ifdef TRXCTL
   cfg.trxcntl = TRX_ADDC;
   *cfg.trxcntl_file = '\0';
 #endif
+  strncpy(cfg.serveraddr, DEFAULT_SERVERADDR, INTBUFSIZE);
   cfg.serverport = DEFAULT_SERVERPORT;
   cfg.maxconn = DEFAULT_MAXCONN;
   cfg.maxtry = DEFAULT_MAXTRY;
   cfg.rqstpause = DEFAULT_RQSTPAUSE;
   cfg.respwait = DEFAULT_RESPWAIT;
-  cfg.resppause = DV(3, cfg.ttyspeed);
   cfg.conntimeout = DEFAULT_CONNTIMEOUT;
-}
-
-static char *
-cfg_rtrim(char *s)
-{
-  char *p = s + strlen(s);
-  while (p > s && isspace((unsigned char )(*--p)))
-    *p = '\0';
-  return s;
-}
-
-static char *
-cfg_ltrim(const char *s)
-{
-  while (*s && isspace((unsigned char )(*s)))
-    s++;
-  return (char *) s;
+  cfg.replyonbroadcast=0;
 }
 
 int
@@ -102,7 +91,13 @@ cfg_handle_param(char *name, char *value)
   }
   else if (CFG_NAME_MATCH("speed"))
   {
-    cfg.ttyspeed = strtoul(value, NULL, 0);
+    char *end;
+    cfg.ttyspeed = strtoul(value, &end, 0);
+    if (!cfg.ttyspeed || value == end || '\0' != *end)
+    {
+      CFG_ERR("invalid serial port speed: %s", value);
+      return 0;
+    }
   }
   else if (CFG_NAME_MATCH("mode"))
   {
@@ -122,6 +117,10 @@ cfg_handle_param(char *name, char *value)
     }
     strncpy(cfg.ttymode, value, INTBUFSIZE);
   }
+  else if (CFG_NAME_MATCH("address"))
+  {
+    strncpy(cfg.serveraddr, value, INTBUFSIZE);
+  }
   else if (CFG_NAME_MATCH("port"))
   {
     cfg.serverport = strtoul(value, NULL, 0);
@@ -161,12 +160,22 @@ cfg_handle_param(char *name, char *value)
       CFG_ERR("invalid wait value: %s", value);
       return 0;
     }
+  }
+   else if (CFG_NAME_MATCH("replyonbroadcast"))
+  {
+    cfg.replyonbroadcast = CFG_VALUE_BOOL();
   }
   else if (CFG_NAME_MATCH("timeout"))
   {
     cfg.conntimeout = strtoul(value, NULL, 0);
     if (cfg.conntimeout > MAX_CONNTIMEOUT)
       return 0;
+#ifdef HAVE_TIOCRS485
+  }
+  else if (CFG_NAME_MATCH("enable_rs485"))
+  {
+    cfg.rs485 = CFG_VALUE_BOOL();
+#endif
 #ifdef TRXCTL
   }
   else if (CFG_NAME_MATCH("trx_control"))
@@ -175,9 +184,13 @@ cfg_handle_param(char *name, char *value)
     {
       cfg.trxcntl = TRX_ADDC;
     }
-    else if (CFG_VALUE_MATCH("rts"))
+    else if (CFG_VALUE_MATCH("rts") || CFG_VALUE_MATCH("rts_1"))
     {
-      cfg.trxcntl = TRX_RTS;
+      cfg.trxcntl = TRX_RTS_1;
+    }
+    else if (CFG_VALUE_MATCH("rts_0"))
+    {
+      cfg.trxcntl = TRX_RTS_0;
     }
     else if (CFG_VALUE_MATCH("sysfs_0"))
     {
@@ -202,7 +215,40 @@ cfg_handle_param(char *name, char *value)
   }
   else if (CFG_NAME_MATCH("loglevel"))
   {
-    cfg.dbglvl = (char)strtol(optarg, NULL, 0);
+    cfg.dbglvl = (char)strtol(value, NULL, 0);
+#  ifdef DEBUG
+    if (!(isdigit(*value)) || cfg.dbglvl < 0 || cfg.dbglvl > 9)
+    { /* report about invalid log level */
+      CFG_ERR("invalid loglevel value: %s (must be 0-9)", value);
+#  else
+    if (!(isdigit(*value)) || cfg.dbglvl < 0 || cfg.dbglvl > 2)
+    { /* report about invalid log level */
+      CFG_ERR("invalid loglevel value: %s (must be 0-2)", value);
+#  endif
+      return 0;
+    }
+  }
+  else if (CFG_NAME_MATCH("logfile"))
+  {
+    if (!strlen(value))
+    {
+      CFG_ERR("missing logfile value", value);
+      return 0;
+    }
+    else if (*value != '/')
+    {
+      if (*value == '-')
+      {
+        /* logging to file disabled */
+        *cfg.logname = '\0';
+      }
+      else
+      { /* concatenate given log file name with default path */
+        strncpy(cfg.logname, LOGPATH, INTBUFSIZE);
+        strncat(cfg.logname, value, INTBUFSIZE - strlen(cfg.logname));
+      }
+    }
+    else strncpy(cfg.logname, value, INTBUFSIZE);
 #endif
   }
   else {
@@ -236,7 +282,7 @@ cfg_parse_file(void *file)
   {
     lineno++;
 
-    start = cfg_ltrim(cfg_rtrim(line));
+    start = util_trim(line);
 
     if (*start == '#')
     {
@@ -251,8 +297,8 @@ cfg_parse_file(void *file)
       {
         *end = '\0';
 
-        name = cfg_rtrim(start);
-        value = cfg_ltrim(cfg_rtrim(end + 1));
+        name = util_rtrim(start);
+        value = util_trim(end + 1);
 
         /* handle name/value pair */
         if (!cfg_handle_param(name, value))

src/cfg.h

@@ -54,10 +54,18 @@ typedef struct
   int ttyspeed;
   /* tty mode */
   char ttymode[INTBUFSIZE + 1];
+#ifdef HAVE_TIOCRS485
+  /* Linux RS-485 support use flag */
+  bool rs485;
+#endif
+#ifdef TRXCTL  
   /* trx control type (0 - ADDC, 1 - by RTS, 2 - by sysfs GPIO with 1 activating transmit, 3 - by sysfs GPIO with 0 activating transmit) */
   int trxcntl;
   /* trx control sysfs file */
   char trxcntl_file[INTBUFSIZE + 1];
+#endif
+  /* TCP server address */
+  char serveraddr[INTBUFSIZE + 1];
   /* TCP server port number */
   int serverport;
   /* maximum number of connections */
@@ -70,8 +78,8 @@ typedef struct
   unsigned long rqstpause;
   /* response waiting time (in msec) */
   unsigned long respwait;
-  /* inter-byte response pause (in usec) */
-  unsigned long resppause;
+  /* reply to client on broadcast */
+  int replyonbroadcast;
 } cfg_t;
 
 /* Prototypes */

src/conn.c

@@ -56,11 +56,7 @@ int tty_reopen()
 {
   logw(3, "tty re-opening...");
   tty_close(&tty);
-#ifdef  TRXCTL
-  tty_init(&tty, cfg.ttyport, cfg.ttyspeed, cfg.trxcntl);
-#else
-  tty_init(&tty, cfg.ttyport, cfg.ttyspeed);
-#endif
+  tty_init(&tty);
   if (tty_open(&tty) != RC_OK)
   {
 #ifdef LOG
@@ -96,11 +92,7 @@ int
 conn_init(void)
 {
   /* tty device initialization */
-#ifdef  TRXCTL
-  tty_init(&tty, cfg.ttyport, cfg.ttyspeed, cfg.trxcntl);
-#else
-  tty_init(&tty, cfg.ttyport, cfg.ttyspeed);
-#endif
+  tty_init(&tty);
   if (tty_open(&tty) != RC_OK)
   {
 #ifdef LOG
@@ -113,13 +105,12 @@ conn_init(void)
   state_tty_set(&tty, TTY_PAUSE);
 
   /* create server socket */
-  if ((server_sd =
-         sock_create_server("", cfg.serverport, TRUE)) < 0)
+  if ((server_sd = sock_create_server(cfg.serveraddr, cfg.serverport, TRUE)) < 0)
   {
 #ifdef LOG
     logw(0, "conn_init():"
-           " can't create listen() socket (%s)",
-           strerror(errno));
+           " can't create listen socket (%s)",
+           (errno != 0) ? strerror(errno) : "failed");
 #endif
     return RC_ERR;
   }
@@ -140,26 +131,28 @@ conn_open(void)
 {
   int sd;
   conn_t *newconn;
-  struct sockaddr_in rmt_addr;
+  struct sockaddr_storage rmt_addr;
+  char ipstr[INET6_ADDRSTRLEN];
 
-  if ((sd = sock_accept(server_sd, &rmt_addr, TRUE)) == RC_ERR)
+  if ((sd = sock_accept(server_sd, (struct sockaddr *)&rmt_addr,
+                        sizeof(rmt_addr), TRUE)) == RC_ERR)
   { /* error in conn_accept() */
 #ifdef LOG
     logw(0, "conn_open(): error in accept() (%s)", strerror(errno));
 #endif
     return;
   }
+ inet_ntop(rmt_addr.ss_family, sock_addr((struct sockaddr *)&rmt_addr),
+           ipstr, sizeof(ipstr));
 #ifdef LOG
-  logw(2, "conn_open(): accepting connection from %s",
-         inet_ntoa(rmt_addr.sin_addr));
+  logw(2, "conn_open(): accepting connection from %s", ipstr);
 #endif
   /* compare descriptor of connection with FD_SETSIZE */
   if (sd >= FD_SETSIZE)
   {
 #ifdef LOG
     logw(1, "conn_open(): FD_SETSIZE limit reached,"
-           " connection from %s will be dropped",
-           inet_ntoa(rmt_addr.sin_addr));
+           " connection from %s will be dropped", ipstr);
 #endif
     close(sd);
     return;
@@ -169,8 +162,7 @@ conn_open(void)
   {
 #ifdef LOG
     logw(1, "conn_open(): number of connections limit reached,"
-           " connection from %s will be dropped",
-           inet_ntoa(rmt_addr.sin_addr));
+           " connection from %s will be dropped", ipstr);
 #endif
     close(sd);
     return;
@@ -178,8 +170,7 @@ conn_open(void)
   /* enqueue connection */
   newconn = queue_new_elem(&queue);
   newconn->sd = sd;
-  memcpy((void *) &newconn->sockaddr,
-         &rmt_addr, sizeof(struct sockaddr_in));
+  memcpy((void *) &newconn->remote_addr, &ipstr, sizeof(ipstr));
   state_conn_set(newconn, CONN_HEADER);
 }
 
@@ -193,8 +184,7 @@ conn_close(conn_t *conn)
 {
   conn_t *nextconn;
 #ifdef LOG
-  logw(2, "conn_close(): closing connection from %s",
-         inet_ntoa(conn->sockaddr.sin_addr));
+  logw(2, "conn_close(): closing connection from %s", conn->remote_addr);
 #endif
   /* close socket */
   close(conn->sd);
@@ -202,6 +192,7 @@ conn_close(conn_t *conn)
   nextconn = queue_next_elem(&queue, conn);
   /* dequeue connection */
   queue_delete_elem(&queue, conn);
+  if (nextconn == conn) nextconn = NULL;
   if (actconn == conn) actconn = nextconn;
   return nextconn;
 }
@@ -237,7 +228,7 @@ conn_read(int d, void *buf, size_t nbytes)
   { /* trying read from descriptor while breaked by signals */
     rc = read(d, buf, nbytes);
   } while (rc == -1 && errno == EINTR);
-  return (rc < 0) ? RC_ERR : rc;
+  return (rc < 0) ? (errno == EAGAIN ? RC_EAGAIN : RC_ERR) : rc;
 }
 
 #include <stdio.h>
@@ -256,43 +247,30 @@ conn_write(int d, void *buf, size_t nbytes, int istty)
   fd_set fs;
   struct timeval ts, tts;
   long delay;
+
 #ifdef TRXCTL
-  if (istty) {
-    if (cfg.trxcntl != TRX_ADDC )
-      tty_set_rts(d);
-    usleep(35000000l/cfg.ttyspeed);
+  if (istty && cfg.trxcntl != TRX_ADDC)
+  {
+    tty_set_tx(d);
+    tty_delay(35000000l/cfg.ttyspeed);
   }
 #endif
+
   FD_ZERO(&fs);
   FD_SET(d, &fs);
   do
-  { /* trying write to descriptor while breaked by signals */
-    gettimeofday(&ts, NULL);
+  {
     rc = write(d, buf, nbytes);
   } while (rc == -1 && errno == EINTR);
-  gettimeofday(&ts, NULL);
-
 
 #ifdef TRXCTL
-  if (istty) {
-#if 1
-    do {
-      gettimeofday(&tts, NULL);
-      delay = DV(nbytes, cfg.ttyspeed) -
-        ((tts.tv_sec * 1000000l + tts.tv_usec) - (ts.tv_sec * 1000000l + ts.tv_usec));
-    } while (delay > 0);
-#else
-    gettimeofday(&tts, NULL);
-    delay = DV(nbytes, cfg.ttyspeed) -
-      ((tts.tv_sec * 1000000l + tts.tv_usec) - (ts.tv_sec * 1000000l + ts.tv_usec));
-    usleep(delay);
-#endif
-/*    tcdrain(d); - hangs sometimes, so make calculated delay */
-    if (cfg.trxcntl != TRX_ADDC ) {
-      tty_clr_rts(d);
-    }
+  if (istty && cfg.trxcntl != TRX_ADDC )
+  {
+    tty_delay(DV(nbytes, tty.bpc, cfg.ttyspeed));
+    tty_set_rx(d);
   }
 #endif
+
   return (rc < 0) ? RC_ERR : rc;
 }
 
@@ -491,8 +469,10 @@ conn_loop(void)
 #endif
                 if (!tty.trynum) {
                   modbus_ex_write(actconn->buf, MB_EX_CRC);
+#ifdef DEBUG
                   logw(3, "tty: response is incorrect (%d of %d bytes, offset %d), return error", tty.ptrbuf,
                     tty.rxoffset + tty.rxlen, tty.rxoffset);
+#endif
                 } else
                 { /* retry request */
 #ifdef DEBUG
@@ -536,15 +516,13 @@ conn_loop(void)
             if (curconn->state == CONN_TTY)
             { /* deadlock in CONN_TTY state, make attempt to reinitialize serial port */
 #ifdef LOG
-              logw(0, "conn[%s]: state CONN_TTY deadlock.",
-                     inet_ntoa(curconn->sockaddr.sin_addr));
+              logw(0, "conn[%s]: state CONN_TTY deadlock.", curconn->remote_addr);
 #endif
               tty_reinit();
             }
             /* purge connection */
 #ifdef LOG
-            logw(2, "conn[%s]: timeout, closing connection",
-                   inet_ntoa(curconn->sockaddr.sin_addr));
+            logw(2, "conn[%s]: timeout, closing connection", curconn->remote_addr);
 #endif
             curconn = conn_close(curconn);
             continue;
@@ -581,34 +559,56 @@ conn_loop(void)
 #ifdef DEBUG
           logw(7, "tty: request written (total %d bytes)", tty.txlen);
 #endif
-          state_tty_set(&tty, TTY_RESP);
-          switch (tty.txbuf[1]) {
-            case 1:
-            case 2:
-              tty.rxlen = 5 + (tty.txbuf[4] * 256 + tty.txbuf[5] + 7)/8;
-              break;
-            case 3:
-            case 4:
-              tty.rxlen = 5 + tty.txbuf[5] * 2;
-              break;
-            case 7:
-              tty.rxlen = 5;
-              break;
-            case 11:
-            case 15:
-            case 16:
-              tty.rxlen = 8;
-              break;
-            default:
-              tty.rxlen = tty.txlen;
-              break;
-          }
-          if (tty.rxlen > TTY_BUFSIZE)
-            tty.rxlen = TTY_BUFSIZE;
-          tty.timer += DV(tty.rxlen, tty.speed);
+          if (!tty.txbuf[0])
+          {
 #ifdef DEBUG
-          logw(5, "tty: estimated %d bytes, waiting %lu usec", tty.rxlen, tty.timer);
+            logw(5, "conn[%s]: broadcast request sent", curconn->remote_addr);
 #endif
+            /* broadcast request sent, no reply expected from TTY*/
+            state_tty_set(&tty, TTY_PAUSE);
+            if (cfg.replyonbroadcast)
+            {
+                /* switch connection to response state, reply w actconn->buf */
+                state_conn_set(actconn, CONN_RESP);
+            }
+            else
+            {
+                /* Done, ready for next */
+                state_conn_set(actconn, CONN_HEADER);
+            }
+
+          }
+          else
+          {
+            state_tty_set(&tty, TTY_RESP);
+            switch (tty.txbuf[1]) {
+              case 1:
+              case 2:
+                tty.rxlen = 5 + (tty.txbuf[4] * 256 + tty.txbuf[5] + 7)/8;
+                break;
+              case 3:
+              case 4:
+                tty.rxlen = 5 + tty.txbuf[5] * 2;
+                break;
+              case 7:
+                tty.rxlen = 5;
+                break;
+              case 11:
+              case 15:
+              case 16:
+                tty.rxlen = 8;
+                break;
+              default:
+                tty.rxlen = tty.txlen;
+                break;
+            }
+            if (tty.rxlen > TTY_BUFSIZE)
+              tty.rxlen = TTY_BUFSIZE;
+            tty.timer += DV(tty.rxlen, tty.bpc, tty.speed);
+#ifdef DEBUG
+            logw(5, "tty: estimated %d bytes, waiting %lu usec", tty.rxlen, tty.timer);
+#endif
+          }
         }
       }
 
@@ -623,59 +623,77 @@ conn_loop(void)
         }
         rc = conn_read(tty.fd, tty.rxbuf + tty.ptrbuf,
                        tty.rxlen - tty.ptrbuf + tty.rxoffset);
-        if (rc <= 0)
+        if (rc == RC_EAGAIN)
+        { /* some tty devices seem to be set as ready to be read by select()
+             while no data is available (see #78) */
+#ifdef LOG
+          logw(5, "tty: read(): no data available");
+#endif
+        }
+        else if (rc <= 0)
         { /* error - make attempt to reinitialize serial port */
 #ifdef LOG
           logw(0, "tty: error in read() (%s)", rc ? strerror(errno) : "port closed");
 #endif
           tty_reinit();
         }
+        else
+        {
 #ifdef DEBUG
           logw(7, "tty: read %d bytes", rc);
 #endif
-        if (tty.ptrbuf - tty.rxoffset < 3 && tty.ptrbuf - tty.rxoffset + rc >= 3) {
-          /* we received more than 3 bytes from header - address, request id and bytes count */
-          if (!tty.rxoffset) {
-            /* offset is unknown */
-            unsigned char i;
-            for (i = 0; i < tty.ptrbuf - tty.rxoffset + rc - 1; i++) {
-              if (tty.rxbuf[i] == tty.txbuf[0] && tty.rxbuf[i+1] == tty.txbuf[1]) {
+          if (tty.ptrbuf - tty.rxoffset < 3 && tty.ptrbuf - tty.rxoffset + rc >= 3) {
+            /* we received more than 3 bytes from header - address, request id and bytes count */
+            if (!tty.rxoffset) {
+              /* offset is unknown */
+              unsigned char i;
+              for (i = 0; i < tty.ptrbuf - tty.rxoffset + rc - 1; i++) {
+                if (tty.rxbuf[i] == tty.txbuf[0] && tty.rxbuf[i+1] == tty.txbuf[1]) {
 #ifdef DEBUG
-                logw(5, "tty: rx offset is %d", i);
+                  logw(5, "tty: rx offset is %d", i);
 #endif
-                tty.rxoffset = i;
-                break;
+                  tty.rxoffset = i;
+                  break;
+                }
+              }
+              switch (tty.txbuf[1]) {
+                case 1:
+                case 2:
+                case 3:
+                case 4:
+                  i = 5 + tty.rxbuf[tty.rxoffset + 2];
+                  break;
+                default:
+                  i = tty.rxlen;
+                  break;
+              }
+              if (i + tty.rxoffset > TTY_BUFSIZE)
+                i = TTY_BUFSIZE - tty.rxoffset;
+              if (i != tty.rxlen) {
+#ifdef DEBUG
+                logw(5, "tty: rx len changed from %d to %d", tty.rxlen, i);
+#endif
+                tty.rxlen = i;
               }
             }
-            switch (tty.txbuf[1]) {
-              case 1:
-              case 2:
-              case 3:
-              case 4:
-                i = 5 + tty.rxbuf[tty.rxoffset + 2];
-                break;
-              default:
-                i = tty.rxlen;
-                break;
-            }
-            if (i + tty.rxoffset > TTY_BUFSIZE)
-              i = TTY_BUFSIZE - tty.rxoffset;
-            if (i != tty.rxlen) {
-#ifdef DEBUG
-              logw(5, "tty: rx len changed from %d to %d", tty.rxlen, i);
-#endif
-              tty.rxlen = i;
-            }
           }
+          tty.ptrbuf += rc;
+          logw(5, "tty: read %d bytes of %d, offset %d", tty.ptrbuf, tty.rxlen + tty.rxoffset, tty.rxoffset);
+          if (tty.ptrbuf == tty.rxlen + tty.rxoffset)
+            state_tty_set(&tty, TTY_PROC);
         }
-        tty.ptrbuf += rc;
-        logw(5, "tty: read %d bytes of %d, offset %d", tty.ptrbuf, tty.rxlen + tty.rxoffset, tty.rxoffset);
-        if (tty.ptrbuf == tty.rxlen + tty.rxoffset)
-          state_tty_set(&tty, TTY_PROC);
       }
       else if (tty.state != TTY_PROC)
       { /* drop unexpected tty data */
-        if ((rc = conn_read(tty.fd, tty.rxbuf, BUFSIZE)) <= 0)
+        rc = conn_read(tty.fd, tty.rxbuf, BUFSIZE);
+        if (rc == RC_EAGAIN)
+        { /* some tty devices seem to be set as ready to be read by select()
+             while no data is available (see #78) */
+#ifdef LOG
+          logw(5, "tty: read(): no data available");
+#endif
+        }
+        else if (rc <= 0)
         { /* error - make attempt to reinitialize serial port */
 #ifdef LOG
           logw(0, "tty: error in read() (%s)", rc ? strerror(errno) : "port closed");
@@ -790,8 +808,7 @@ conn_loop(void)
                 /* check request function code */
                 unsigned char fc = MB_FRAME(curconn->buf, MB_FCODE);
 #ifdef DEBUG
-                logw(7, "conn[%s]: read request fc %d",
-                     inet_ntoa(curconn->sockaddr.sin_addr), fc);
+                logw(7, "conn[%s]: read request fc %d", curconn->remote_addr, fc);
 #endif
                 switch (fc)
                 {
@@ -846,11 +863,12 @@ conn_loop(void)
               { /* ### frame received completely ### */
 #ifdef DEBUG
                 t[0] = '\0';
+                int i;
                 for (i = MB_UNIT_ID; i < curconn->ctr; i++) {
                   sprintf(v, "[%2.2x]", curconn->buf[i]);
                   strncat(t, v, 1024-strlen(t));
                 }
-                logw(5, "conn[%s]: request: %s", inet_ntoa(curconn->sockaddr.sin_addr), t);
+                logw(5, "conn[%s]: request: %s", curconn->remote_addr, t);
 #endif
                 state_conn_set(curconn, CONN_TTY);
                 if (tty.state == TTY_READY)
@@ -896,7 +914,7 @@ conn_fix_request_header_len(conn_t *conn, unsigned char len)
   {
 #ifdef DEBUG
     logw(5, "conn[%s]: request data len changed from %d to %d",
-         MB_FRAME(conn->buf, MB_LENGTH_L), len);
+         conn->remote_addr, MB_FRAME(conn->buf, MB_LENGTH_L), len);
 #endif
     MB_FRAME(conn->buf, MB_LENGTH_L) = len;
   }

src/conn.h

@@ -46,6 +46,7 @@
 /*
  * Default values
  */
+#define DEFAULT_SERVERADDR "0.0.0.0"
 #define DEFAULT_SERVERPORT 502
 #define DEFAULT_MAXCONN 32
 #define DEFAULT_MAXTRY 3
@@ -103,7 +104,7 @@ typedef struct conn_t
   int sd;               /* socket descriptor */
   int state;            /* current state */
   int timeout;          /* timeout value, secs */
-  struct sockaddr_in sockaddr; /* connection structure */
+  char remote_addr[INET6_ADDRSTRLEN]; /* remote client address */
   int ctr;              /* counter of data in the buffer */
   int read_len;         /* length of modbus frame to read */
   unsigned char buf[HDRSIZE + BUFSIZE];    /* data buffer */

src/crc16.c

@@ -1,79 +0,0 @@
-/*
- * OpenMODBUS/TCP to RS-232/485 MODBUS RTU gateway
- *
- * crc16.c - Cyclic Redundant Checks calculating
- *
- * Copyright (c) 2002-2003, 2013, Victor Antonovich (v.antonovich@gmail.com)
- * 
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 
- * - Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 
- * - Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * $Id: crc16.c,v 1.3 2015/02/25 10:33:57 kapyar Exp $
- */
-
-#include "crc16.h"
-
-unsigned short
-crc_16_tab[] = {
-  0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
-  0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
-  0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
-  0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
-  0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
-  0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
-  0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
-  0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
-  0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
-  0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
-  0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
-  0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
-  0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
-  0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
-  0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
-  0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
-  0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
-  0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
-  0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
-  0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
-  0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
-  0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
-  0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
-  0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
-  0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
-  0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
-  0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
-  0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
-  0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
-  0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
-  0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
-  0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
-};
-
-unsigned short
-crc16(unsigned char *buf, unsigned int bsize)
-{
-  unsigned short crc = 0xffff;
-  while (bsize--)
-    crc = (unsigned short)(crc >> 8) ^ crc_16_tab[(crc ^ *buf++) & 0xff];
-  return crc;
-}

src/globals.h

@@ -59,6 +59,7 @@
 #include <netdb.h>
 #include <fcntl.h>
 #include <ctype.h>
+#include <stdbool.h>
 #ifdef HAVE_LIBUTIL
 #  include <libutil.h>
 #endif
@@ -84,6 +85,7 @@
 #define RC_TIMEOUT -3
 #define RC_AOPEN   -4
 #define RC_ACLOSE  -5
+#define RC_EAGAIN  -6
 
 /* Internal string buffers size */
 #if defined(PATH_MAX)

src/log.h

@@ -40,7 +40,7 @@ extern int isdaemon;
 
 /* Default log file path and name */
 #define LOGPATH "/var/log/"
-#define LOGNAME "mbus.log"
+#define LOGNAME "mbusd.log"
 
 #ifdef LOG
 int log_init(char *logname);

src/main.c

@@ -40,6 +40,7 @@
 #include "conn.h"
 #include "queue.h"
 #include "sig.h"
+#include "util.h"
 #ifdef LOG
 #  include "log.h"
 #endif
@@ -100,67 +101,85 @@ void
 usage(char *exename)
 {
   cfg_init();
-  printf("%s-%s Copyright (C) 2002-2003, 2011, 2013-2019 Victor Antonovich <v.antonovich@gmail.com>, "
+  printf("%s-%s Copyright (C) 2002-2003, 2011, 2013-2024 Victor Antonovich <v.antonovich@gmail.com>, "
    "Andrew Denysenko <nitr0@seti.kr.ua>\n\n"
    "Usage: %s [-h] [-d] "
 #ifdef LOG
    "[-L logfile] [-v level] "
 #endif
    "[-c cfgfile] \n"
-   "             [-p device] [-s speed] [-m mode]\n"
-#ifdef TRXCTL
-   "             [-t] [-y sysfsfile] [-Y sysfsfile]\n"
+   "             [-p device] [-s speed] [-m mode]"
+#ifdef HAVE_TIOCRS485
+   " [-S]"
 #endif
-   "             [-P port] [-C maxconn] [-N retries] [-R pause] [-W wait] [-T timeout]\n\n"
+   "\n"   
+#ifdef TRXCTL
+   "             [-t] [-r] [-y sysfsfile] [-Y sysfsfile]\n"
+#endif
+   "             [-A address] [-P port] [-C maxconn] [-N retries]\n"
+   "             [-R pause] [-W wait] [-T timeout] [-b]\n\n"
    "Options:\n"
    "  -h         : this help\n"
-   "  -d         : don't daemonize\n"
+   "  -d         : don't fork (non-daemonize)\n"
 #ifdef LOG
-   "  -L logfile : set log file name (default %s%s, \n"
+   "  -L logfile : set log file name (default is %s%s, \n"
    "               '-' for logging to STDOUT only)\n"
 #ifdef DEBUG
-   "  -v level   : set log level (0-9, default %d, 0 - errors only)\n"
+   "  -v level   : set log level (0-9, default is %d, 0 - errors only)\n"
 #else
    "  -v level   : set log level (0-2, default %d, 0 - errors only)\n"
 #endif
 #endif
    "  -c cfgfile : read configuration from cfgfile\n"
-   "  -p device  : set serial port device name (default %s)\n"
-   "  -s speed   : set serial port speed (default %d)\n"
-   "  -m mode    : set serial port mode (default %s)\n"
-   "  -P port    : set TCP server port number (default %d)\n"
+   "  -p device  : set serial port device name (default is %s)\n"
+   "  -s speed   : set serial port speed (default is %d)\n"
+   "  -m mode    : set serial port mode (default is %s)\n"
+#ifdef HAVE_TIOCRS485
+   "  -S         : enable Linux RS-485 support for given serial port device\n"
+#endif   
 #ifdef TRXCTL
-   "  -t         : enable RTS RS-485 data direction control using RTS\n"
+   "  -t         : enable RTS RS-485 data direction control using RTS, active transmit\n"
+   "  -r         : enable RTS RS-485 data direction control using RTS, active receive\n"
    "  -y         : enable RTS RS-485 data direction control using sysfs file, active transmit\n"
+   "               (writes '1' to sysfs file for transmit enable, '0' for transmit disable)\n"
    "  -Y         : enable RTS RS-485 data direction control using sysfs file, active receive\n"
+   "               (writes '0' to sysfs file for transmit enable, '1' for transmit disable)\n"
 #endif
+   "  -A address : set TCP server address to bind (default is %s)\n"
+   "  -P port    : set TCP server port number (default is %d)\n"
    "  -C maxconn : set maximum number of simultaneous TCP connections\n"
-   "               (1-%d, default %d)\n"
+   "               (1-%d, default is %d)\n"
    "  -N retries : set maximum number of request retries\n"
-   "               (0-%d, default %d, 0 - without retries)\n"
+   "               (0-%d, default is %d, 0 disables retrying)\n"
    "  -R pause   : set pause between requests in milliseconds\n"
-   "               (1-%d, default %lu)\n"
+   "               (1-%d, default is %lu)\n"
    "  -W wait    : set response wait time in milliseconds\n"
-   "               (1-%d, default %lu)\n"
+   "               (1-%d, default is %lu)\n"
    "  -T timeout : set connection timeout value in seconds\n"
-   "               (0-%d, default %d, 0 - no timeout)"
+   "               (0-%d, default is %d, 0 disables timeout)\n"
+   "  -b         : enable reply on broadcast"
    "\n", PACKAGE, VERSION, exename,
 #ifdef LOG
       LOGPATH, LOGNAME, cfg.dbglvl,
 #endif
-      cfg.ttyport, cfg.ttyspeed, cfg.ttymode, cfg.serverport,
+      cfg.ttyport, cfg.ttyspeed, cfg.ttymode,
+      cfg.serveraddr, cfg.serverport,
       MAX_MAXCONN, cfg.maxconn, MAX_MAXTRY, cfg.maxtry,
       MAX_RQSTPAUSE, cfg.rqstpause, MAX_RESPWAIT, cfg.respwait,
       MAX_CONNTIMEOUT, cfg.conntimeout);
   exit(0);
 }
 
+
 int
 main(int argc, char *argv[])
 {
   int err = 0, rc, err_line;
   char *exename;
   char ttyparity;
+  char *end;
+  char *logfilenamevalue;
+  char *logfilename;
 
   sig_init();
 
@@ -177,10 +196,13 @@ main(int argc, char *argv[])
 #ifdef TRXCTL
                "ty:Y:"
 #endif
+#ifdef HAVE_TIOCRS485
+               "S"
+#endif
 #ifdef LOG
                "v:L:"
 #endif
-               "p:s:m:P:C:N:R:W:T:c:")) != RC_ERR)
+               "p:s:m:A:P:C:N:R:W:T:c:b")) != RC_ERR)
   {
     switch (rc)
     {
@@ -203,38 +225,53 @@ main(int argc, char *argv[])
         break;
 #ifdef TRXCTL
       case 't':
-        cfg.trxcntl = TRX_RTS;
+        cfg.trxcntl = TRX_RTS_1;
+        break;
+      case 'r':
+        cfg.trxcntl = TRX_RTS_0;
         break;
       case 'y':
         cfg.trxcntl = TRX_SYSFS_1;
         strncpy(cfg.trxcntl_file, optarg, INTBUFSIZE);
-	break;
+	      break;
       case 'Y':
         cfg.trxcntl = TRX_SYSFS_0;
         strncpy(cfg.trxcntl_file, optarg, INTBUFSIZE);
-	break;
+	      break;
+#endif
+#ifdef HAVE_TIOCRS485
+      case 'S':
+        cfg.rs485 = TRUE;
+	      break;
 #endif
 #ifdef LOG
       case 'v':
         cfg.dbglvl = (char)strtol(optarg, NULL, 0);
 #  ifdef DEBUG
-        if (cfg.dbglvl > 9)
+        if (!(isdigit(*optarg)) || cfg.dbglvl < 0 || cfg.dbglvl > 9)
         { /* report about invalid log level */
           printf("%s: -v: invalid loglevel value"
-                 " (%d, must be 0-9)\n", exename, cfg.dbglvl);
+                 " (%s, must be 0-9)\n", exename, optarg);
 #  else
-        if (cfg.dbglvl < 0 || cfg.dbglvl > 9)
+        if (!(isdigit(*optarg)) || cfg.dbglvl < 0 || cfg.dbglvl > 2)
         { /* report about invalid log level */
           printf("%s: -v: invalid loglevel value"
-                 " (%d, must be 0-2)\n", exename, cfg.dbglvl);
+                 " (%s, must be 0-2)\n", exename, optarg);
 #  endif
           exit(-1);
         }
         break;
       case 'L':
-        if (*optarg != '/')
+        logfilenamevalue = strdup(optarg);
+        logfilename = util_trim(logfilenamevalue);
+        if (!strlen(logfilename))
+        { /* report about empty log file */
+          printf("%s: -L: log file name is empty, exiting...\n", exename);
+          exit(-1);
+        }
+        else if (*logfilename != '/')
         {
-          if (*optarg == '-')
+          if (*logfilename == '-')
           {
             /* logging to file disabled */
             *cfg.logname = '\0';
@@ -242,10 +279,11 @@ main(int argc, char *argv[])
           else
           { /* concatenate given log file name with default path */
             strncpy(cfg.logname, LOGPATH, INTBUFSIZE);
-            strncat(cfg.logname, optarg, INTBUFSIZE - strlen(cfg.logname));
+            strncat(cfg.logname, logfilename, INTBUFSIZE - strlen(cfg.logname));
           }
         }
-        else strncpy(cfg.logname, optarg, INTBUFSIZE);
+        else strncpy(cfg.logname, logfilename, INTBUFSIZE);
+        free(logfilenamevalue);
         break;
 #endif
       case 'p':
@@ -258,7 +296,12 @@ main(int argc, char *argv[])
         else strncpy(cfg.ttyport, optarg, INTBUFSIZE);
         break;
       case 's':
-        cfg.ttyspeed = strtoul(optarg, NULL, 0);
+        cfg.ttyspeed = strtoul(optarg, &end, 10);
+        if (!cfg.ttyspeed || optarg == end || '\0' != *end)
+        {
+          printf("%s: -s: invalid serial port speed (%s)\n", exename, optarg);
+          exit(-1);
+        }
         break;
       case 'm':
         strncpy(cfg.ttymode, optarg, INTBUFSIZE);
@@ -290,6 +333,9 @@ main(int argc, char *argv[])
           exit(-1);
         }
         break;
+      case 'A':
+        strncpy(cfg.serveraddr, optarg, INTBUFSIZE);
+        break;
       case 'P':
         cfg.serverport = strtoul(optarg, NULL, 0);
         break;
@@ -338,6 +384,9 @@ main(int argc, char *argv[])
           exit(-1);
         }
         break;
+      case 'b':
+        cfg.replyonbroadcast = 1;
+        break;
       case 'h':
         usage(exename);
         break;

src/modbus.c

@@ -34,6 +34,57 @@
 #include "modbus.h"
 #include "conn.h"
 
+static const unsigned short
+modbus_crc16_table[] = {
+  0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
+  0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
+  0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
+  0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
+  0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
+  0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
+  0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
+  0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
+  0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
+  0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
+  0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
+  0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
+  0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
+  0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
+  0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
+  0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
+  0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
+  0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
+  0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
+  0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
+  0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
+  0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
+  0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
+  0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
+  0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
+  0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
+  0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
+  0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
+  0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
+  0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
+  0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
+  0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
+};
+
+/*
+ * Calculate Modbus frame CRC (Cyclical Redundancy Checking) value
+ * Parameters: FRAME - address of the frame,
+ *             LEN   - frame length;
+ * Return: calculated CRC value
+ */
+static unsigned short
+modbus_crc_calculate(unsigned char *frame, unsigned int len)
+{
+  unsigned short crc = 0xffff;
+  while (len--)
+    crc = (unsigned short)(crc >> 8) ^ modbus_crc16_table[(crc ^ *frame++) & 0xff];
+  return crc;
+}
+
 /*
  * Check CRC of MODBUS frame
  * Parameters: FRAME - address of the frame,
@@ -44,7 +95,7 @@
 int
 modbus_crc_correct(unsigned char *frame, unsigned int len)
 {
-  return (!crc16(frame, len));
+  return (!modbus_crc_calculate(frame, len));
 }
 
 /*
@@ -56,7 +107,7 @@ modbus_crc_correct(unsigned char *frame, unsigned int len)
 void
 modbus_crc_write(unsigned char *frame, unsigned int len)
 {
-  WORD_WR_LE(frame + len, crc16(frame, len));
+  WORD_WR_LE(frame + len, modbus_crc_calculate(frame, len));
 }
 
 /*

src/modbus.h

@@ -35,7 +35,6 @@
 #define _MODBUS_H
 
 #include "globals.h"
-#include "crc16.h"
 
 /*
  * Macro for accessing data in MODBUS frame

src/queue.c

@@ -115,5 +115,5 @@ queue_delete_elem(queue_t *queue, conn_t *conn)
 conn_t *
 queue_next_elem(queue_t *queue, conn_t *conn)
 {
-  return (conn->next == NULL) ? queue->beg : conn->next;
+  return (conn == NULL || conn->next == NULL) ? queue->beg : conn->next;
 }

src/sock.c

@@ -58,12 +58,11 @@ sock_set_blkmode(int sd, int blkmode)
  * Return: socket descriptor, otherwise RC_ERR if there some errors
  */
 int
-sock_create(int blkmode)
+sock_create(int blkmode, sa_family_t sa_family)
 {
   int sock;
 
-  if ((sock =
-         socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1)
+  if ((sock = socket(sa_family, SOCK_STREAM, IPPROTO_TCP)) == -1)
   {
 #ifdef LOG
     logw(0, "sock_create(): unable to create socket (%s)",
@@ -94,15 +93,52 @@ sock_create(int blkmode)
  * Return: socket descriptor, otherwise RC_ERR if there some errors
  */
 int
-sock_create_server(char *server_ip,
-  unsigned short server_port, int blkmode)
+sock_create_server(char *server_ip, unsigned short server_port, int blkmode)
 {
-  struct sockaddr_in server_sockaddr;
+  struct sockaddr_storage server_sockaddr;
   int sock_opt = 1;
   int server_s;
 
+  memset(&server_sockaddr, 0, sizeof(server_sockaddr));
+
+  /* parse address to bind socket */
+  if (server_ip != NULL)
+  {
+    /* try first to parse server_ip as IPv6 address, if it fail, try to parse as IPv4 */
+    if (inet_pton(AF_INET6, server_ip,
+                  &(*((struct sockaddr_in6 *)&server_sockaddr)).sin6_addr) != 0)
+      server_sockaddr.ss_family = AF_INET6;
+    else if (inet_pton(AF_INET, server_ip,
+                       &(*((struct sockaddr_in *)&server_sockaddr)).sin_addr) != 0)
+      server_sockaddr.ss_family = AF_INET;
+    else
+    {
+#ifdef LOG
+      logw(0, "sock_create_server():"
+           " can't parse address: %s",
+           server_ip);
+#endif
+      return RC_ERR;
+    }
+  }
+  else
+  {
+    server_sockaddr.ss_family = AF_INET; // TODO AF_INET6/in6addr_any?
+    (*((struct sockaddr_in *)&server_sockaddr)).sin_addr.s_addr = htonl(INADDR_ANY);
+  }
+
+  /* parse IP port */
+  switch (server_sockaddr.ss_family) {
+    case AF_INET:
+      (*((struct sockaddr_in *)&server_sockaddr)).sin_port = htons(server_port);
+      break;
+    case AF_INET6:
+      (*((struct sockaddr_in6 *)&server_sockaddr)).sin6_port = htons(server_port);
+      break;
+  }
+
   /* create socket in desired blocking mode */
-  server_s = sock_create(blkmode);
+  server_s = sock_create(blkmode, server_sockaddr.ss_family);
   if (server_s < 0) return server_s;
 
   /* set to close socket on exec() */
@@ -144,18 +180,9 @@ sock_create_server(char *server_ip,
     return RC_ERR;
   }
 
-  memset(&server_sockaddr, 0, sizeof(server_sockaddr));
-  server_sockaddr.sin_family = AF_INET;
-
-  if (server_ip != NULL)
-    inet_aton(server_ip, &server_sockaddr.sin_addr);
-  else
-    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
-
-  server_sockaddr.sin_port = htons(server_port);
-
-  if (bind(server_s, (struct sockaddr *) & server_sockaddr,
-	   sizeof(server_sockaddr)) == -1)
+  /* bind socket to given address and port */
+  if (bind(server_s, (struct sockaddr *)&server_sockaddr,
+           sa_len((struct sockaddr *)&server_sockaddr)) == -1)
   {
 #ifdef LOG
     logw(0, "sock_create_server():"
@@ -187,13 +214,11 @@ sock_create_server(char *server_ip,
  *         RMT_ADDR - ptr to connection info structure
  */
 int
-sock_accept(int server_sd, struct sockaddr_in *rmt_addr, int blkmode)
+sock_accept(int server_sd, struct sockaddr *rmt_addr, socklen_t rmt_len, int blkmode)
 {
   int sd, sock_opt = SOCKBUFSIZE;
-  int rmt_len = sizeof(struct sockaddr_in);
 
-  sd = accept(server_sd, (struct sockaddr *) rmt_addr,
-              (socklen_t *) &rmt_len);
+  sd = accept(server_sd, rmt_addr, &rmt_len);
   if (sd == -1)
   {
     if (errno != EAGAIN && errno != EWOULDBLOCK)
@@ -207,7 +232,7 @@ sock_accept(int server_sd, struct sockaddr_in *rmt_addr, int blkmode)
   if (sock_set_blkmode(sd, blkmode) == RC_ERR)
   {
 #ifdef LOG
-    logw(0, "sock_accept(): can't set socket blocking mode (%s)", 
+    logw(0, "sock_accept(): can't set socket blocking mode (%s)",
            strerror(errno));
 #endif
     close(sd);
@@ -230,3 +255,17 @@ sock_accept(int server_sd, struct sockaddr_in *rmt_addr, int blkmode)
   }
   return sd;
 }
+
+/*
+ * Return reference to socket address structure according to its family (AF_INET/AF_INET6)
+ */
+void *
+sock_addr(struct sockaddr *sa)
+{
+  if (sa->sa_family == AF_INET)
+  {
+    return &(((struct sockaddr_in*)sa)->sin_addr);
+  }
+
+  return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}

src/sock.h

@@ -1,21 +1,21 @@
 /*
  * OpenMODBUS/TCP to RS-232/485 MODBUS RTU gateway
  *
- * sock.h - socket manipulation routines 
+ * sock.h - socket manipulation routines
  *
  * Copyright (c) 2002-2003, 2013, Victor Antonovich (v.antonovich@gmail.com)
- * 
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
- * 
+ *
  * - Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
- * 
+ *
  * - Redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
@@ -44,11 +44,13 @@
 /* Socket buffers size */
 #define SOCKBUFSIZE 512
 
+#define sa_len(sa_ptr) ((sa_ptr)->sa_family == AF_INET \
+    ? sizeof (struct sockaddr_in) : sizeof (struct sockaddr_in6))
+
 int sock_set_blkmode(int sd, int blkmode);
-int sock_create(int blkmode);
-int sock_create_server(char *server_ip,
-  unsigned short server_port, int blkmode);
-int sock_accept(int server_sd,
-  struct sockaddr_in *rmt_addr, int blkmode);
+int sock_create(int blkmode, sa_family_t sa_family);
+int sock_create_server(char *server_ip, unsigned short server_port, int blkmode);
+int sock_accept(int server_sd, struct sockaddr *rmt_addr, socklen_t rmt_len, int blkmode);
+void *sock_addr(struct sockaddr *sa);
 
 #endif

src/state.c

@@ -76,47 +76,40 @@ state_conn_set(conn_t *conn, int state)
       conn->ctr = 0;
       conn->read_len = HDRSIZE;
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_HEADER",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_HEADER", conn->remote_addr);
 #endif
       break;
     case CONN_RQST_FUNC:
       conn->read_len = HDRSIZE + MB_FRAME(conn->buf, MB_LENGTH_L);
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_RQST_FUNC",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_RQST_FUNC", conn->remote_addr);
 #endif
     break;
     case CONN_RQST_NVAL:
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_RQST_NVAL",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_RQST_NVAL", conn->remote_addr);
 #endif
     break;
     case CONN_RQST_TAIL:
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_RQST_TAIL",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_RQST_TAIL", conn->remote_addr);
 #endif
     break;
     case CONN_TTY:
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_TTY",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_TTY", conn->remote_addr);
 #endif
       break;
     case CONN_RESP:
       conn->ctr = 0;
 #ifdef DEBUG
-      logw(5, "conn[%s]: state now is CONN_RESP",
-             inet_ntoa(conn->sockaddr.sin_addr));
+      logw(5, "conn[%s]: state now is CONN_RESP", conn->remote_addr);
 #endif
       break;
     default:
       /* unknown state, exiting */
 #ifdef DEBUG
-      logw(5, "conn_set_state([%s]) - invalid state (%d)",
-             inet_ntoa(conn->sockaddr.sin_addr), state);
+      logw(5, "conn_set_state([%s]) - invalid state (%d)", conn->remote_addr, state);
 #endif
       exit (-1);
   }
@@ -155,7 +148,7 @@ state_tty_set(ttydata_t *mod, int state)
       logw(5, "tty: state now is TTY_RQST");
 #endif
 #ifndef NOSILENT
-      tty_delay(DV(2, cfg.ttyspeed));
+      tty_delay(DV(2, mod->bpc, cfg.ttyspeed));
 #endif
       break;
     case TTY_RESP:
@@ -163,7 +156,7 @@ state_tty_set(ttydata_t *mod, int state)
       mod->rxoffset = 0;
       /* XXX need real recv length? */
       mod->rxlen = TTY_BUFSIZE;
-      mod->timer = cfg.respwait * 1000l + DV(mod->txlen, mod->speed);
+      mod->timer = cfg.respwait * 1000l + DV(mod->txlen, mod->bpc, mod->speed);
 #ifdef DEBUG
       logw(5, "tty: state now is TTY_RESP");
 #endif

src/tty.c

@@ -48,20 +48,28 @@ tty_sighup(void)
 }
 
 /*
- * Init serial link parameters MOD to PORT name, SPEED and TRXCNTL type
+ * Init serial link parameters
  */
 void
-#ifdef  TRXCTL
-tty_init(ttydata_t *mod, char *port, int speed, int trxcntl)
-#else
-tty_init(ttydata_t *mod, char *port, int speed)
-#endif
+tty_init(ttydata_t *mod)
 {
   mod->fd = -1;
-  mod->port = port;
-  mod->speed = speed;
-#ifdef  TRXCTL
-  mod->trxcntl = trxcntl;
+  mod->port = cfg.ttyport;
+  mod->speed = cfg.ttyspeed;
+  mod->bpc = DEFAULT_BITS_PER_CHAR;
+  if (toupper(cfg.ttymode[1]) != 'N')
+  {
+    mod->bpc++;
+  }
+  if (cfg.ttymode[2] == '2')
+  {
+    mod->bpc++;
+  }
+#ifdef HAVE_TIOCRS485
+  mod->rs485 = cfg.rs485;
+#endif
+#ifdef TRXCTL
+  mod->trxcntl = cfg.trxcntl;
 #endif
 }
 
@@ -109,6 +117,9 @@ tty_open(ttydata_t *mod)
     errno = buferr;
     return RC_ERR;
   }
+#endif
+#ifdef LOG
+  logw(2, "tty: trying to open %s (speed %d mode %s)", mod->port, mod->speed, cfg.ttymode);
 #endif
   mod->fd = open(mod->port, O_RDWR | O_NONBLOCK | O_NOCTTY);
   if (mod->fd < 0)
@@ -178,7 +189,26 @@ tty_set_attr(ttydata_t *mod)
     return RC_ERR;
   tcflush(mod->fd, TCIOFLUSH);
 #ifdef  TRXCTL
-  tty_clr_rts(mod->fd);
+  tty_set_rx(mod->fd);
+#endif
+#ifdef HAVE_TIOCRS485
+  if (mod->rs485)
+  {
+    struct serial_rs485 rs485conf;
+#ifdef LOG
+    logw(2, "tty: trying to enable RS-485 support for %s", mod->port);
+#endif
+    if (ioctl(mod->fd, TIOCGRS485, &rs485conf) < 0) {
+        return RC_ERR;
+    }
+    rs485conf.flags |= SER_RS485_ENABLED;
+    if (ioctl(mod->fd, TIOCSRS485, &rs485conf) < 0) {
+        return RC_ERR;
+    }
+#ifdef LOG
+    logw(2, "tty: enabled RS-485 support for %s", mod->port);
+#endif    
+  }
 #endif
   flag = fcntl(mod->fd, F_GETFL, 0);
   if (flag < 0)
@@ -195,9 +225,6 @@ tty_transpeed(int speed)
   speed_t tspeed;
   switch (speed)
   {
-  case 0:
-    tspeed = B0;
-    break;
 #if defined(B50)
   case 50:
     tspeed = B50;
@@ -306,9 +333,76 @@ tty_transpeed(int speed)
     tspeed = B115200;
     break;
 #endif
-  default:
-    tspeed = DEFAULT_BSPEED;
+#if defined(B230400)
+  case 230400:
+    tspeed = B230400;
     break;
+#endif
+#if defined(B460800)
+  case 460800:
+    tspeed = B460800;
+    break;
+#endif
+#if defined(B500000)
+  case 500000:
+    tspeed = B500000;
+    break;
+#endif
+#if defined(B576000)
+  case 576000:
+    tspeed = B576000;
+    break;
+#endif
+#if defined(B921600)
+  case 921600:
+    tspeed = B921600;
+    break;
+#endif
+#if defined(B1000000)
+  case 1000000:
+    tspeed = B1000000;
+    break;
+#endif
+#if defined(B1152000)
+  case 1152000:
+    tspeed = B1152000;
+    break;
+#endif
+#if defined(B1500000)
+  case 1500000:
+    tspeed = B1500000;
+    break;
+#endif
+#if defined(B2000000)
+  case 2000000:
+    tspeed = B2000000;
+    break;
+#endif
+#if defined(B2500000)
+  case 2500000:
+    tspeed = B2500000;
+    break;
+#endif
+#if defined(B3000000)
+  case 3000000:
+    tspeed = B3000000;
+    break;
+#endif
+#if defined(B3500000)
+  case 3500000:
+    tspeed = B3500000;
+    break;
+#endif
+#if defined(B4000000)
+  case 4000000:
+    tspeed = B4000000;
+    break;
+#endif
+  default:
+#ifdef LOG
+    logw(0, "tty: unsupported speed: %d", speed);
+#endif
+    exit (-1);
   }
   return tspeed;
 }
@@ -371,27 +465,33 @@ void sysfs_gpio_set(char *filename, char *value) {
 
 }
 
-/* Set RTS line to active state */
+/* Set tty device into transmit mode */
 void
-tty_set_rts(int fd)
+tty_set_tx(int fd)
 {
-	if ( TRX_RTS == cfg.trxcntl ) {
+	if ( TRX_RTS_1 == cfg.trxcntl ) {
 		int mstat = TIOCM_RTS;
 		ioctl(fd, TIOCMBIS, &mstat);
-	} else if ( TRX_SYSFS_1 == cfg.trxcntl) {
+	} else if ( TRX_RTS_0 == cfg.trxcntl ) {
+		int mstat = TIOCM_RTS;
+		ioctl(fd, TIOCMBIC, &mstat);
+  } else if ( TRX_SYSFS_1 == cfg.trxcntl) {
 		sysfs_gpio_set(cfg.trxcntl_file,"1");
 	} else if ( TRX_SYSFS_0 == cfg.trxcntl) {
 		sysfs_gpio_set(cfg.trxcntl_file,"0");
 	}
 }
 
-/* Set RTS line to passive state */
+/* Set tty device into receive mode */
 void
-tty_clr_rts(int fd)
+tty_set_rx(int fd)
 {
-	if ( TRX_RTS == cfg.trxcntl ) {
+	if ( TRX_RTS_1 == cfg.trxcntl ) {
 		int mstat = TIOCM_RTS;
 		ioctl(fd, TIOCMBIC, &mstat);
+	} else if ( TRX_RTS_0 == cfg.trxcntl ) {
+		int mstat = TIOCM_RTS;
+		ioctl(fd, TIOCMBIS, &mstat);
 	} else if ( TRX_SYSFS_1 == cfg.trxcntl) {
 		sysfs_gpio_set(cfg.trxcntl_file,"0");
 	} else if ( TRX_SYSFS_0 == cfg.trxcntl) {
@@ -412,7 +512,7 @@ tty_delay(int usec)
   do
   {
     (void)gettimeofday(&ttv, NULL);
-    ts = 1000000 * (ttv.tv_sec - tv.tv_sec) + (ttv.tv_usec - tv.tv_usec);
+    ts = 1000000l * (ttv.tv_sec - tv.tv_sec) + (ttv.tv_usec - tv.tv_usec);
   } while (ts < usec && !tty_break);
 }
 

src/tty.h

@@ -34,13 +34,20 @@
 #ifndef _TTY_H
 #define _TTY_H
 
+#ifdef HAVE_TIOCRS485
+#include <linux/serial.h>
+#endif
+
 #include "globals.h"
 #include "cfg.h"
 
 /*
- * Delay value calculation macros
+ * Delay value calculation macros.
+ * c - number of characters
+ * b - bits per character
+ * s - bits per second
  */
-#define	DV(x, y) (x * 10000000l / y)
+#define	DV(c, b, s) (c * b * 1000000l / s)
 
 /*
  * Default tty port parameters
@@ -58,6 +65,8 @@
 
 #define DEFAULT_MODE "8N1"
 
+#define DEFAULT_BITS_PER_CHAR 10
+
 /*
  * Maximum tty buffer size
  */
@@ -68,9 +77,10 @@
  */
 #ifdef  TRXCTL
 #define TRX_ADDC    0
-#define TRX_RTS     1
-#define TRX_SYSFS_1 2
-#define TRX_SYSFS_0 3
+#define TRX_RTS_1   1
+#define TRX_RTS_0   2
+#define TRX_SYSFS_1 3
+#define TRX_SYSFS_0 4
 #endif
 
 /*
@@ -90,6 +100,10 @@ typedef struct
   int fd;                       /* tty file descriptor */
   int speed;                    /* serial port speed */
   char *port;                   /* serial port device name */
+  int bpc;                      /* bits per character */
+#ifdef HAVE_TIOCRS485
+  bool rs485;                   /* use Linux RS-485 support flag */
+#endif
 #ifdef TRXCTL
   int trxcntl;                  /* trx control type (enum - see values in config.h) */
 #endif
@@ -108,18 +122,14 @@ typedef struct
 
 /* prototypes */
 void tty_sighup(void);
-#ifdef TRXCTL
-void tty_init(ttydata_t *mod, char *port, int speed, int trxcntl);
-#else
-void tty_init(ttydata_t *mod, char *port, int speed);
-#endif
+void tty_init(ttydata_t *mod);
 int tty_open(ttydata_t *mod);
 int tty_set_attr(ttydata_t *mod);
 speed_t tty_transpeed(int speed);
 int tty_cooked(ttydata_t *mod);
 int tty_close(ttydata_t *mod);
-void tty_set_rts(int fd);
-void tty_clr_rts(int fd);
+void tty_set_tx(int fd);
+void tty_set_rx(int fd);
 void tty_delay(int usec);
 
 #endif /* _TTY_H */

src/util.c

@@ -0,0 +1,80 @@
+/*
+ * OpenMODBUS/TCP to RS-232/485 MODBUS RTU gateway
+ *
+ * util.h - utility functions
+ *
+ * Copyright (c) 2002-2023, Victor Antonovich (v.antonovich@gmail.com)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "util.h"
+
+#include <ctype.h>
+#include <string.h>
+
+/**
+ * Removes leading whitespace from the string. 
+ * Parameters: s - the string to be trimmed.
+ * Return: a pointer to the first non-whitespace character in string.
+ */
+char *
+util_ltrim(const char *s)
+{
+  while (*s && isspace((unsigned char )(*s)))
+    s++;
+  return (char *) s;
+}
+
+/**
+ * Removes trailing whitespace from the string. 
+ * The first trailing whitespace is replaced with a NUL-terminator
+ * in the given string.
+ * Parameters: s - the string to be trimmed.
+ * Return: a pointer to the string.
+ */
+char *
+util_rtrim(char *s)
+{
+  char *p = s + strlen(s);
+  while (p > s && isspace((unsigned char )(*--p)))
+    *p = '\0';
+  return s;
+}
+
+/**
+ * Removes leading and trailing whitespace from the string. 
+ * The first trailing whitespace is replaced with a NUL-terminator
+ * in the given string.
+ * Parameters: s - the string to be trimmed.
+ * Return: a pointer to the first non-whitespace character in string.
+ */
+char *
+util_trim(char *s)
+{
+	if (!strlen(s))
+		return s;
+
+	return util_ltrim(util_rtrim(s));
+}

src/util.h

@@ -1,21 +1,21 @@
 /*
  * OpenMODBUS/TCP to RS-232/485 MODBUS RTU gateway
  *
- * crc16.h - Cyclic Redundant Checks calculating
+ * util.h - utility functions
+ *
+ * Copyright (c) 2002-2023, Victor Antonovich (v.antonovich@gmail.com)
  *
- * Copyright (c) 2002-2003, 2013, Victor Antonovich (v.antonovich@gmail.com)
- * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
- * 
+ *
  * - Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
- * 
+ *
  * - Redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
@@ -27,15 +27,13 @@
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * $Id: crc16.h,v 1.3 2015/02/25 10:33:57 kapyar Exp $
  */
- 
-#ifndef _CRC_H
-#define _CRC_H
 
-#include "globals.h"
+#ifndef _UTIL_H
+#define _UTIL_H
 
-unsigned short crc16(unsigned char *buf, unsigned int bsize);
+char *util_ltrim(const char *s);
+char *util_rtrim(char *s);
+char *util_trim(char *s);
 
-#endif /*_CRC_H */
+#endif /* _UTIL_H */

systemd-units/mbusd@.service.in

@@ -1,9 +1,11 @@
 [Unit]
 Description=Modbus TCP to Modbus RTU (RS-232/485) gateway.
 Requires=network.target
+After=network-online.target
+Wants=network-online.target
 
 [Service]
-ExecStart=@CMAKE_INSTALL_FULL_BINDIR@/mbusd -d -v2 -L - -c @CMAKE_INSTALL_FULL_SYSCONFDIR@/mbusd/mbusd-%i.conf -p /dev/%i
+ExecStart=@CMAKE_INSTALL_FULL_BINDIR@/mbusd -d -v2 -L - -c @CMAKE_INSTALL_FULL_SYSCONFDIR@/mbusd/mbusd-%i.conf -p /dev/%I
 Restart=on-failure
 RestartSec=1
 StandardOutput=journal

tests/environment/rtu_slave.py

@@ -14,7 +14,7 @@ import logging
 #---------------------------------------------------------------------------#
 #from pymodbus.server.async import StartTcpServer
 #from pymodbus.server.async import StartUdpServer
-from pymodbus.server.asynchronous import StartSerialServer
+from pymodbus.server import StartSerialServer
 
 from pymodbus.device import ModbusDeviceIdentification
 from pymodbus.datastore import ModbusSequentialDataBlock
@@ -92,7 +92,7 @@ class ModbusSerialServer:
             hr = ModbusSequentialDataBlock(0, [0]*8), # holding regs
             ir = ModbusSequentialDataBlock(0, list(range(8))), # input regs
             zero_mode=True) # request(0-7) will map to the address (0-7)
-        context = ModbusServerContext(slaves=store, single=True)
+        context = ModbusServerContext(slaves={1: store}, single=False)
 
         #---------------------------------------------------------------------------#
         # initialize the server information
@@ -112,7 +112,7 @@ class ModbusSerialServer:
         #---------------------------------------------------------------------------#
         #StartTcpServer(context, identity=identity, address=("localhost", 5020))
         #StartUdpServer(context, identity=identity, address=("localhost", 502))
-        StartSerialServer(context, identity=identity, port=self.serialPort, baudrate=19200, framer=framer)
+        StartSerialServer(context=context, identity=identity, port=self.serialPort, baudrate=19200, framer=framer, broadcast_enable=True)
         #StartSerialServer(context, identity=identity, port='/dev/pts/3', framer=ModbusAsciiFramer)
 
     p = None

tests/run_itests.py

@@ -8,7 +8,7 @@ from subprocess import Popen, PIPE, STDOUT
 from os.path import isfile
 from time import sleep
 
-from pymodbus.client.sync import ModbusTcpClient
+from pymodbus.client import ModbusTcpClient
 from pymodbus.pdu import ExceptionResponse
 from pymodbus.bit_read_message import ReadDiscreteInputsResponse, ReadCoilsResponse
 from pymodbus.bit_write_message import WriteMultipleCoilsResponse, WriteSingleCoilResponse
@@ -33,7 +33,7 @@ class TestModbusRequests(unittest.TestCase):
         cls.mbs.start()
 
         cls.log.debug("3. run mbusd to be tested with the binary:%s" % MBUSD_BINARY)
-        cls.mbusd_main = Popen([MBUSD_BINARY, "-d", "-L", "-v9", "-p/tmp/pts0", "-s19200", "-P" + str(MBUSD_PORT)],
+        cls.mbusd_main = Popen([MBUSD_BINARY, "-d", "-L/tmp/mbusd.log", "-v9", "-p/tmp/pts0", "-s19200", "-P" + str(MBUSD_PORT)],
                                stdout=PIPE, stderr=STDOUT)
         # wait a little bit for mbusd to come up
         # alternatively do a poll for the socket
@@ -41,7 +41,7 @@ class TestModbusRequests(unittest.TestCase):
         sleep(5)
 
         cls.log.debug("4. connect the modbus TCP client to mbusd")
-        cls.client = ModbusTcpClient('127.0.0.1', port=MBUSD_PORT)
+        cls.client = ModbusTcpClient('127.0.0.1', port=MBUSD_PORT, broadcast_enable=True)
         cls.client.connect()
 
     @classmethod
@@ -62,35 +62,35 @@ class TestModbusRequests(unittest.TestCase):
         bits = [random.randrange(2)>0 for i in range(8)]
 
         # 15 Write Multiple Coils
-        result = self.client.write_coils(0, bits)
+        result = self.client.write_coils(0, bits, slave=1)
         self.assertIsInstance(result, WriteMultipleCoilsResponse, result)
         self.assertEqual(result.address, 0, result)
         self.assertEqual(result.count, 8, result)
 
         # 01 Read Coils
-        result = self.client.read_coils(0, 8)
+        result = self.client.read_coils(0, 8, slave=1)
         self.assertIsInstance(result, ReadCoilsResponse, result)
         self.assertEqual(result.bits, bits, result)
 
         # 05 Write Single Coil
         bit1 = not bits[0]
-        result = self.client.write_coil(0, bit1)
+        result = self.client.write_coil(0, bit1, slave=1)
         self.assertIsInstance(result, WriteSingleCoilResponse, result)
         self.assertEqual(result.address, 0, result)
         self.assertEqual(result.value, bit1, result)
-        result = self.client.read_coils(0, 1)
+        result = self.client.read_coils(0, 1, slave=1)
         self.assertIsInstance(result, ReadCoilsResponse, result)
         self.assertEqual(result.bits[0], bit1, result)
 
     def test_discreteInputs(self):
         # 02 Read Discrete Inputs
-        result = self.client.read_discrete_inputs(0, 8)
+        result = self.client.read_discrete_inputs(0, 8, slave=1)
         self.assertIsInstance(result, ReadDiscreteInputsResponse, result)
         self.assertEqual(result.bits, [True]*8, result)
 
     def test_inputRegisters(self):
         # 04 Read Input Registers
-        result = self.client.read_input_registers(0, 8)
+        result = self.client.read_input_registers(0, 8, slave=1)
         self.assertIsInstance(result, ReadInputRegistersResponse, result)
         self.assertEqual(result.registers, list(range(8)), result)
 
@@ -98,32 +98,42 @@ class TestModbusRequests(unittest.TestCase):
         registers = [random.randrange(8) for i in range(8)]
 
         # 16 Write Multiple Holding Registers
-        result = self.client.write_registers(0, registers)
+        result = self.client.write_registers(0, registers, slave=1)
         self.assertIsInstance(result, WriteMultipleRegistersResponse, result)
         self.assertEqual(result.address, 0, result)
         self.assertEqual(result.count, 8, result)
 
         # 03 Read Multiple Holding Registers
-        result = self.client.read_holding_registers(0, 8)
+        result = self.client.read_holding_registers(0, 8, slave=1)
         self.assertIsInstance(result, ReadHoldingRegistersResponse, result)
         self.assertEqual(result.registers, registers, result)
 
         # 06 Write Single Holding Register
         register1 = (registers[0] + 1) % 65535
-        result = self.client.write_register(0, register1)
+        result = self.client.write_register(0, register1, slave=1)
         self.assertIsInstance(result, WriteSingleRegisterResponse, result)
         self.assertEqual(result.address, 0, result)
         self.assertEqual(result.value, register1, result)
-        result = self.client.read_holding_registers(0, 1)
+        result = self.client.read_holding_registers(0, 1, slave=1)
         self.assertIsInstance(result, ReadHoldingRegistersResponse, result)
         self.assertEqual(result.registers[0], register1, result)
 
     def test_exception(self):
-        result = self.client.write_coil(1000, False) # invalid address 1000
+        result = self.client.write_coil(1000, False, slave=1) # invalid address 1000
         self.assertIsInstance(result, ExceptionResponse, result)
         self.assertEqual(result.original_code, 5, result) # fc05 Write Single Coil
         self.assertEqual(result.exception_code, 2, result) # Illegal Data Address
 
+    def test_broadcast(self):
+        registers = [random.randrange(8) for i in range(8)]
+        # 16 Write Multiple Holding Registers
+        result = self.client.write_registers(0, registers, slave=0)
+
+        # 03 Read Multiple Holding Registers
+        result = self.client.read_holding_registers(0, 8, slave=1)
+        self.assertIsInstance(result, ReadHoldingRegistersResponse, result)
+        self.assertEqual(result.registers, registers, result)
+
 if __name__ == '__main__':
     stdout_handler = logging.StreamHandler(sys.stdout)
     logging.basicConfig(level=logging.DEBUG,