Examples, fixes

.gitignore

@@ -1,3 +1,7 @@
 .idea
+cmake-build*
+build*
 /tests/cmake-build*
 /tests/build*
+/examples/cmake-build*
+/examples/build*

CMakeLists.txt

@@ -0,0 +1,17 @@
+cmake_minimum_required(VERSION 3.21)
+project(modbusino C)
+
+set(CMAKE_C_STANDARD 99)
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -pedantic")
+set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -O0 -g")
+set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3")
+
+include_directories(tests .)
+
+#add_definitions(-DMBSN_DEBUG)
+
+add_executable(modbusino_tests modbusino.c tests/modbusino_tests.c)
+add_executable(client-tcp modbusino.c examples/client-tcp.c)
+add_executable(server-tcp modbusino.c examples/server-tcp.c)
+
+target_link_libraries(modbusino_tests pthread)

examples/client-tcp.c

@@ -0,0 +1,92 @@
+#include "modbusino.h"
+#include "platform.h"
+#include <stdio.h>
+
+/*
+ * This example application connects via TCP to a modbus server at the specified address and port, and sends some
+ * modbus requests to it.
+ *
+ * Since the platform for this example is linux, the platform arg is used to pass (to the linux TCP read/write
+ * functions) a pointer to the file descriptor of our TCP connection
+ *
+ * The platform functions are for Linux systems.
+ */
+
+int main(int argc, char* argv[]) {
+    if (argc < 3) {
+        fprintf(stderr, "Usage: client-tcp [address] [port]\n");
+        return 1;
+    }
+
+    // Set up the TCP connection
+    void* conn = connect_tcp(argv[1], argv[2]);
+    if (!conn) {
+        fprintf(stderr, "Error connecting to server\n");
+        return 1;
+    }
+
+    mbsn_platform_conf platform_conf;
+    platform_conf.transport = MBSN_TRANSPORT_TCP;
+    platform_conf.read_byte = read_byte_fd_linux;
+    platform_conf.write_byte = write_byte_fd_linux;
+    platform_conf.sleep = sleep_linux;
+    platform_conf.arg = conn;    // Passing our TCP connection handle to the read/write functions
+
+    // Create the modbus client
+    mbsn_t mbsn;
+    mbsn_error err = mbsn_client_create(&mbsn, &platform_conf);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error creating modbus client\n");
+        return 1;
+    }
+
+    // Set only the response timeout. Byte timeout will be handled by the TCP connection
+    mbsn_set_read_timeout(&mbsn, 1000);
+
+    // Write 2 coils from address 64
+    mbsn_bitfield coils;
+    mbsn_bitfield_write(coils, 0, 1);
+    mbsn_bitfield_write(coils, 1, 1);
+    err = mbsn_write_multiple_coils(&mbsn, 64, 2, coils);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error writing coils at address 64 - %s\n", mbsn_strerror(err));
+        return 1;
+    }
+
+    // Read 3 coils from address 64
+    mbsn_bitfield_reset(coils);    // Reset whole bitfield to zero
+    err = mbsn_read_coils(&mbsn, 64, 3, coils);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error reading coils at address 64 - %s\n", mbsn_strerror(err));
+        return 1;
+    }
+
+    printf("Coil at address 64 value: %d\n", mbsn_bitfield_read(coils, 0));
+    printf("Coil at address 65 value: %d\n", mbsn_bitfield_read(coils, 1));
+    printf("Coil at address 66 value: %d\n", mbsn_bitfield_read(coils, 2));
+
+    // Write 2 holding registers at address 26
+    uint16_t w_regs[2] = {123, 124};
+    err = mbsn_write_multiple_registers(&mbsn, 26, 2, w_regs);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error writing register at address 26 - %s", mbsn_strerror(err));
+        return 1;
+    }
+
+    // Read 2 holding registers from address 26
+    uint16_t r_regs[2];
+    err = mbsn_read_holding_registers(&mbsn, 26, 2, r_regs);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error reading 2 holding registers at address 26 - %s\n", mbsn_strerror(err));
+        return 1;
+    }
+
+    printf("Register at address 26: %d\n", r_regs[0]);
+    printf("Register at address 27: %d\n", r_regs[1]);
+
+    // Close the TCP connection
+    disconnect(conn);
+
+    // No need to destroy the mbsn instance, bye bye
+    return 0;
+}

examples/platform.h

@@ -0,0 +1,231 @@
+#include "modbusino.h"
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/select.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+
+// Read/write/sleep platform functions
+
+int read_byte_fd_linux(uint8_t* b, int32_t timeout_ms, void* arg) {
+    int fd = *(int*) arg;
+
+    fd_set rfds;
+    FD_ZERO(&rfds);
+    FD_SET(fd, &rfds);
+
+    struct timeval* tv_p = NULL;
+    struct timeval tv;
+    if (timeout_ms >= 0) {
+        tv_p = &tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+    }
+
+    int ret = select(fd + 1, &rfds, NULL, NULL, tv_p);
+    if (ret == 0) {
+        return 0;
+    }
+    else if (ret == 1) {
+        ssize_t r = read(fd, b, 1);
+        if (r != 1)
+            return -1;
+        else {
+            return 1;
+        }
+    }
+    else
+        return -1;
+}
+
+
+int write_byte_fd_linux(uint8_t b, int32_t timeout_ms, void* arg) {
+    int fd = *(int*) arg;
+
+    fd_set wfds;
+    FD_ZERO(&wfds);
+    FD_SET(fd, &wfds);
+
+    struct timeval* tv_p = NULL;
+    struct timeval tv;
+    if (timeout_ms >= 0) {
+        tv_p = &tv;
+        tv.tv_sec = timeout_ms / 1000;
+        tv.tv_usec = (timeout_ms % 1000) * 1000;
+    }
+
+    int ret = select(fd + 1, NULL, &wfds, NULL, tv_p);
+    if (ret == 0) {
+        return 0;
+    }
+    else if (ret == 1) {
+        ssize_t r = write(fd, &b, 1);
+        if (r != 1)
+            return -1;
+        else {
+            return 1;
+        }
+    }
+    else
+        return -1;
+}
+
+
+void sleep_linux(uint32_t milliseconds, void* arg) {
+    usleep(milliseconds * 1000);
+}
+
+
+// Connection management
+
+int client_connection = -1;
+
+void* connect_tcp(const char* address, const char* port) {
+    struct addrinfo ainfo = {0};
+    struct addrinfo *results, *rp;
+    int fd;
+
+    ainfo.ai_family = AF_INET;
+    ainfo.ai_socktype = SOCK_STREAM;
+    int ret = getaddrinfo(address, port, &ainfo, &results);
+    if (ret != 0)
+        return NULL;
+
+    for (rp = results; rp != NULL; rp = rp->ai_next) {
+        fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (fd == -1)
+            continue;
+
+        ret = connect(fd, rp->ai_addr, rp->ai_addrlen);
+        if (ret == 0)
+            break;
+        else
+            close(fd);
+    }
+
+    freeaddrinfo(results);
+
+    if (rp == NULL)
+        return NULL;
+
+    client_connection = fd;
+    return &client_connection;
+}
+
+
+int server_fd = -1;
+int client_read_fd = -1;
+fd_set client_connections;
+
+void close_server_on_exit(int sig) {
+    if (server_fd != -1)
+        close(server_fd);
+}
+
+
+int create_tcp_server(const char* address, const char* port) {
+    struct addrinfo ainfo = {0};
+    struct addrinfo *results, *rp;
+    int fd = -1;
+
+    ainfo.ai_family = AF_INET;
+    ainfo.ai_socktype = SOCK_STREAM;
+    int ret = getaddrinfo(address, port, &ainfo, &results);
+    if (ret != 0)
+        return -1;
+
+    for (rp = results; rp != NULL; rp = rp->ai_next) {
+        fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (fd == -1)
+            continue;
+
+        ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int));
+        if (ret != 0)
+            return -1;
+
+        ret = bind(fd, rp->ai_addr, rp->ai_addrlen);
+        if (ret != 0) {
+            close(fd);
+            fd = -1;
+            continue;
+        }
+
+        ret = listen(fd, 1);
+        if (ret != 0) {
+            close(fd);
+            fd = -1;
+            continue;
+        }
+
+        break;
+    }
+
+    freeaddrinfo(results);
+
+    signal(SIGINT, close_server_on_exit);
+    signal(SIGTERM, close_server_on_exit);
+    signal(SIGQUIT, close_server_on_exit);
+    signal(SIGSTOP, close_server_on_exit);
+    signal(SIGHUP, close_server_on_exit);
+
+    server_fd = fd;
+    FD_ZERO(&client_connections);
+
+    return 0;
+}
+
+
+void* server_poll() {
+    fd_set read_fd_set;
+    FD_ZERO(&read_fd_set);
+
+    while (true) {
+        read_fd_set = client_connections;
+        FD_SET(server_fd, &read_fd_set);
+
+        int ret = select(FD_SETSIZE, &read_fd_set, NULL, NULL, NULL);
+        if (ret < 0)
+            return NULL;
+
+        for (int i = 0; i < FD_SETSIZE; ++i) {
+            if (FD_ISSET(i, &read_fd_set)) {
+                if (i == server_fd) {
+                    struct sockaddr_in client_addr;
+                    socklen_t client_addr_size = sizeof(client_addr);
+
+                    int client = accept(server_fd, (struct sockaddr*) &client_addr, &client_addr_size);
+                    if (client < 0) {
+                        fprintf(stderr, "Error accepting client connection from %s - %s\n",
+                                inet_ntoa(client_addr.sin_addr), strerror(errno));
+                        continue;
+                    }
+
+                    FD_SET(client, &client_connections);
+                    printf("Accepted connection from %s\n", inet_ntoa(client_addr.sin_addr));
+                }
+                else {
+                    client_read_fd = i;
+                    return &client_read_fd;
+                }
+            }
+        }
+    }
+}
+
+
+void disconnect(void* conn) {
+    int fd = *(int*) conn;
+    close(fd);
+}
+
+
+void close_server() {
+    close(server_fd);
+}

examples/server-handlers.h

@@ -0,0 +1,63 @@
+#include "modbusino.h"
+
+// Server (slave) handler functions
+
+// This server data model will support coils addresses 0 to 100 and registers addresses from 0 to 26
+#define COILS_ADDR_MAX 100
+#define REGS_ADDR_MAX 32
+
+// A single mbsn_bitfield variable can keep 2000 coils
+mbsn_bitfield server_coils = {0};
+
+uint16_t server_registers[REGS_ADDR_MAX] = {0};
+
+
+mbsn_error handle_read_coils(uint16_t address, uint16_t quantity, mbsn_bitfield coils_out) {
+    if (address + quantity > COILS_ADDR_MAX + 1)
+        return MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS;
+
+    // Read our coils values into coils_out
+    for (int i = 0; i < quantity; i++) {
+        bool value = mbsn_bitfield_read(server_coils, address + i);
+        mbsn_bitfield_write(coils_out, i, value);
+    }
+
+    return MBSN_ERROR_NONE;
+}
+
+
+mbsn_error handle_write_multiple_coils(uint16_t address, uint16_t quantity, const mbsn_bitfield coils) {
+    if (address + quantity > COILS_ADDR_MAX + 1)
+        return MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS;
+
+    // Write coils values to our server_coils
+    for (int i = 0; i < quantity; i++) {
+        mbsn_bitfield_write(server_coils, address + i, mbsn_bitfield_read(coils, i));
+    }
+
+    return MBSN_ERROR_NONE;
+}
+
+
+mbsn_error handler_read_holding_registers(uint16_t address, uint16_t quantity, uint16_t* registers_out) {
+    if (address + quantity > REGS_ADDR_MAX + 1)
+        return MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS;
+
+    // Read our registers values into registers_out
+    for (int i = 0; i < quantity; i++)
+        registers_out[i] = server_registers[address + i];
+
+    return MBSN_ERROR_NONE;
+}
+
+
+mbsn_error handle_write_multiple_registers(uint16_t address, uint16_t quantity, const uint16_t* registers) {
+    if (address + quantity > REGS_ADDR_MAX + 1)
+        return MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS;
+
+    // Write registers values to our server_registers
+    for (int i = 0; i < quantity; i++)
+        server_registers[address + i] = registers[i];
+
+    return MBSN_ERROR_NONE;
+}

examples/server-tcp.c

@@ -0,0 +1,85 @@
+#include "modbusino.h"
+#include "platform.h"
+#include "server-handlers.h"
+#include <stdio.h>
+
+/*
+ * This example application sets up a TCP server at the specified address and port, and polls from modbus requests
+ * from more than one modbus client (more specifically from maximum 1024 clients, since it uses select())
+ *
+ * This example server supports the following function codes:
+ * FC 01 (0x01) Read Coils
+ * FC 03 (0x03) Read Holding Registers
+ * FC 15 (0x0F) Write Multiple Coils
+ * FC 16 (0x10) Write Multiple registers
+ *
+* Since the platform for this example is linux, the platform arg is used to pass (to the linux TCP read/write
+* functions) a pointer to the file descriptor of the current read client connection
+ *
+ * The platform functions are for Linux systems.
+ */
+
+int main(int argc, char* argv[]) {
+    if (argc < 3) {
+        fprintf(stderr, "Usage: server-tcp [address] [port]\n");
+        return 1;
+    }
+
+    // Set up the TCP server
+    int ret = create_tcp_server(argv[1], argv[2]);
+    if (ret != 0) {
+        fprintf(stderr, "Error creating TCP server\n");
+        return 1;
+    }
+
+    mbsn_platform_conf platform_conf = {0};
+    platform_conf.transport = MBSN_TRANSPORT_TCP;
+    platform_conf.read_byte = read_byte_fd_linux;
+    platform_conf.write_byte = write_byte_fd_linux;
+    platform_conf.sleep = sleep_linux;
+    platform_conf.arg = NULL;    // We will set the arg (socket fd) later
+
+    // These functions are defined in server.h
+    mbsn_callbacks callbacks = {0};
+    callbacks.read_coils = handle_read_coils;
+    callbacks.write_multiple_coils = handle_write_multiple_coils;
+    callbacks.read_holding_registers = handler_read_holding_registers;
+    callbacks.write_multiple_registers = handle_write_multiple_registers;
+
+    // Create the modbus server. It's ok to set address_rtu to 0 since we are on TCP
+    mbsn_t mbsn;
+    mbsn_error err = mbsn_server_create(&mbsn, 0, &platform_conf, &callbacks);
+    if (err != MBSN_ERROR_NONE) {
+        fprintf(stderr, "Error creating modbus server\n");
+        return 1;
+    }
+
+    // Set only the polling timeout. Byte timeout will be handled by the TCP connection
+    mbsn_set_read_timeout(&mbsn, 1000);
+
+    printf("Modbus TCP server started\n");
+
+    // Our server supports requests from more than one client
+    while (true) {
+        // Our server_poll() function will return the next client TCP connection to read from
+        void* conn = server_poll();
+        if (!conn)
+            break;
+
+        // Set the next connection handler used by the read/write platform functions
+        mbsn_set_platform_arg(&mbsn, conn);
+
+        err = mbsn_server_poll(&mbsn);
+        if (err != MBSN_ERROR_NONE) {
+            fprintf(stderr, "Error polling modbus connection - %s\n", mbsn_strerror(err));
+            // In a more complete example, we should handle this error by closing the connection from our side
+            break;
+        }
+    }
+
+    // Close the TCP server
+    close_server();
+
+    // No need to destroy the mbsn instance, bye bye
+    return 0;
+}

modbusino.c

@@ -60,16 +60,17 @@ static void msg_state_reset(mbsn_t* mbsn) {
 
 
 static void msg_state_req(mbsn_t* mbsn, uint8_t fc) {
-    static uint16_t TID = 1;
+    if (mbsn->current_tid == UINT16_MAX)
+        mbsn->current_tid = 1;
+    else
+        mbsn->current_tid++;
 
     msg_state_reset(mbsn);
     mbsn->msg.unit_id = mbsn->dest_address_rtu;
     mbsn->msg.fc = fc;
-    mbsn->msg.transaction_id = TID;
+    mbsn->msg.transaction_id = mbsn->current_tid;
-    if (mbsn->msg.unit_id == 0)
+    if (mbsn->msg.unit_id == 0 && mbsn->platform.transport == MBSN_TRANSPORT_RTU)
         mbsn->msg.broadcast = true;
-
-    TID++;
 }
 
 
@@ -103,17 +104,17 @@ mbsn_error mbsn_client_create(mbsn_t* mbsn, const mbsn_platform_conf* platform_c
 }
 
 
-mbsn_error mbsn_server_create(mbsn_t* mbsn, uint8_t address, const mbsn_platform_conf* transport_conf,
+mbsn_error mbsn_server_create(mbsn_t* mbsn, uint8_t address_rtu, const mbsn_platform_conf* platform_conf,
-                              mbsn_callbacks callbacks) {
+                              const mbsn_callbacks* callbacks) {
-    if (address == 0)
+    if (platform_conf->transport == MBSN_TRANSPORT_RTU && address_rtu == 0)
         return MBSN_ERROR_INVALID_ARGUMENT;
 
-    mbsn_error ret = mbsn_create(mbsn, transport_conf);
+    mbsn_error ret = mbsn_create(mbsn, platform_conf);
     if (ret != MBSN_ERROR_NONE)
         return ret;
 
-    mbsn->address_rtu = address;
+    mbsn->address_rtu = address_rtu;
-    mbsn->callbacks = callbacks;
+    mbsn->callbacks = *callbacks;
 
     return MBSN_ERROR_NONE;
 }
@@ -139,9 +140,14 @@ void mbsn_set_destination_rtu_address(mbsn_t* mbsn, uint8_t address) {
 }
 
 
-static uint16_t crc_calc(const uint8_t* data, unsigned int length) {
+void mbsn_set_platform_arg(mbsn_t* mbsn, void* arg) {
+    mbsn->platform.arg = arg;
+}
+
+
+static uint16_t crc_calc(const uint8_t* data, uint32_t length) {
     uint16_t crc = 0xFFFF;
-    for (int i = 0; i < length; i++) {
+    for (uint32_t i = 0; i < length; i++) {
         crc ^= (uint16_t) data[i];
         for (int j = 8; j != 0; j--) {
             if ((crc & 0x0001) != 0) {
@@ -158,9 +164,10 @@ static uint16_t crc_calc(const uint8_t* data, unsigned int length) {
 
 
 static mbsn_error recv(mbsn_t* mbsn, uint32_t count) {
-    int r = 0;
+    uint32_t r = 0;
     while (r != count) {
-        int ret = mbsn->platform.read_byte(mbsn->msg.buf + mbsn->msg.buf_idx + r, mbsn->byte_timeout_ms);
+        int ret = mbsn->platform.read_byte(mbsn->msg.buf + mbsn->msg.buf_idx + r, mbsn->byte_timeout_ms,
+                                           mbsn->platform.arg);
         if (ret == 0) {
 #ifdef MBSN_DEBUG
             if (mbsn->address_rtu == 0)
@@ -195,9 +202,9 @@ static mbsn_error send(mbsn_t* mbsn) {
 
     for (int i = 0; i < mbsn->msg.buf_idx; i++) {
         if (spacing_ms != 0)
-            mbsn->platform.sleep(spacing_ms);
+            mbsn->platform.sleep(spacing_ms, mbsn->platform.arg);
 
-        int ret = mbsn->platform.write_byte(mbsn->msg.buf[i], mbsn->read_timeout_ms);
+        int ret = mbsn->platform.write_byte(mbsn->msg.buf[i], mbsn->read_timeout_ms, mbsn->platform.arg);
         if (ret == 0) {
             return MBSN_ERROR_TIMEOUT;
         }
@@ -307,13 +314,15 @@ static mbsn_error recv_req_header(mbsn_t* mbsn, bool* first_byte_received) {
     if (err != MBSN_ERROR_NONE)
         return err;
 
-    // Check if request is for us
+    if (mbsn->platform.transport == MBSN_TRANSPORT_RTU) {
-    if (mbsn->msg.unit_id == MBSN_BROADCAST_ADDRESS)
+        // Check if request is for us
-        mbsn->msg.broadcast = true;
+        if (mbsn->msg.unit_id == MBSN_BROADCAST_ADDRESS)
-    else if (mbsn->msg.unit_id != mbsn->address_rtu)
+            mbsn->msg.broadcast = true;
-        mbsn->msg.ignored = true;
+        else if (mbsn->msg.unit_id != mbsn->address_rtu)
-    else
+            mbsn->msg.ignored = true;
-        mbsn->msg.ignored = false;
+        else
+            mbsn->msg.ignored = false;
+    }
 
     return MBSN_ERROR_NONE;
 }
@@ -374,9 +383,6 @@ static void send_msg_header(mbsn_t* mbsn, uint16_t data_length) {
     }
 
     put_1(mbsn, mbsn->msg.fc);
-
-    if (mbsn->msg.unit_id == MBSN_BROADCAST_ADDRESS)
-        mbsn->msg.broadcast = true;
 }
 
 
@@ -776,7 +782,7 @@ static mbsn_error handle_req_fc(mbsn_t* mbsn) {
 }
 
 
-mbsn_error mbsn_server_receive(mbsn_t* mbsn) {
+mbsn_error mbsn_server_poll(mbsn_t* mbsn) {
     msg_state_reset(mbsn);
 
     bool first_byte_received = false;
@@ -788,75 +794,6 @@ mbsn_error mbsn_server_receive(mbsn_t* mbsn) {
             return err;
     }
 
-    /*
-    // We should wait for the read timeout for the first message byte
-    int32_t old_byte_timeout = mbsn->byte_timeout_ms;
-    mbsn->byte_timeout_ms = mbsn->read_timeout_ms;
-
-    if (mbsn->transport == MBSN_TRANSPORT_RTU) {
-        uint8_t id;
-        mbsn_error err = recv_1(mbsn, &id, &req.crc);
-
-        mbsn->byte_timeout_ms = old_byte_timeout;
-
-        if (err != 0) {
-            if (err == MBSN_ERROR_TIMEOUT)
-                return MBSN_ERROR_NONE;
-            else
-                return err;
-        }
-
-        // Check if request is for us
-        if (id == 0)
-            req.broadcast = true;
-        else if (id != mbsn->address_rtu)
-            req.ignored = true;
-        else
-            req.ignored = false;
-
-        err = recv_1(mbsn, &req.fc, &req.crc);
-        if (err != MBSN_ERROR_NONE)
-            return err;
-    }
-    else if (mbsn->transport == MBSN_TRANSPORT_TCP) {
-        mbsn_error err = recv_2(mbsn, &req.transaction_id, NULL);
-
-        mbsn->byte_timeout_ms = old_byte_timeout;
-
-        if (err != 0) {
-            if (err == MBSN_ERROR_TIMEOUT)
-                return MBSN_ERROR_NONE;
-            else
-                return err;
-        }
-
-        uint16_t protocol_id = 0xFFFF;
-        err = recv_2(mbsn, &protocol_id, NULL);
-        if (err != MBSN_ERROR_NONE)
-            return err;
-
-        uint16_t length = 0xFFFF;
-        err = recv_2(mbsn, &length, NULL);
-        if (err != MBSN_ERROR_NONE)
-            return err;
-
-        err = recv_1(mbsn, &req.unit_id, NULL);
-        if (err != MBSN_ERROR_NONE)
-            return err;
-
-        err = recv_1(mbsn, &req.fc, NULL);
-        if (err != MBSN_ERROR_NONE)
-            return err;
-
-        if (protocol_id != 0)
-            return MBSN_ERROR_TRANSPORT;
-
-        // TODO maybe we should actually check the length of the request against this value
-        if (length == 0xFFFF)
-            return MBSN_ERROR_TRANSPORT;
-    }
-     */
-
     err = handle_req_fc(mbsn);
     if (err != MBSN_ERROR_NONE) {
         if (!mbsn_error_is_exception(err))
@@ -1159,7 +1096,7 @@ mbsn_error mbsn_write_multiple_registers(mbsn_t* mbsn, uint16_t address, uint16_
 mbsn_error mbsn_send_raw_pdu(mbsn_t* mbsn, uint8_t fc, const void* data, uint32_t data_len) {
     msg_state_req(mbsn, fc);
     send_msg_header(mbsn, data_len);
-    for (int i = 0; i < data_len; i++) {
+    for (uint32_t i = 0; i < data_len; i++) {
         put_1(mbsn, ((uint8_t*) (data))[i]);
     }
 
@@ -1176,7 +1113,7 @@ mbsn_error mbsn_receive_raw_pdu_response(mbsn_t* mbsn, void* data_out, uint32_t
     if (err != MBSN_ERROR_NONE)
         return err;
 
-    for (int i = 0; i < data_out_len; i++) {
+    for (uint32_t i = 0; i < data_out_len; i++) {
         ((uint8_t*) (data_out))[i] = get_1(mbsn);
     }
 
@@ -1186,3 +1123,40 @@ mbsn_error mbsn_receive_raw_pdu_response(mbsn_t* mbsn, void* data_out, uint32_t
 
     return MBSN_ERROR_NONE;
 }
+
+
+#ifndef MBSN_STRERROR_DISABLED
+const char* mbsn_strerror(mbsn_error error) {
+    switch (error) {
+        case MBSN_ERROR_TRANSPORT:
+            return "transport error";
+
+        case MBSN_ERROR_TIMEOUT:
+            return "timeout";
+
+        case MBSN_ERROR_INVALID_RESPONSE:
+            return "invalid response received";
+
+        case MBSN_ERROR_INVALID_ARGUMENT:
+            return "invalid argument provided";
+
+        case MBSN_ERROR_NONE:
+            return "no error";
+
+        case MBSN_EXCEPTION_ILLEGAL_FUNCTION:
+            return "modbus exception 1: illegal function";
+
+        case MBSN_EXCEPTION_ILLEGAL_DATA_ADDRESS:
+            return "modbus exception 2: illegal data address";
+
+        case MBSN_EXCEPTION_ILLEGAL_DATA_VALUE:
+            return "modbus exception 3: data value";
+
+        case MBSN_EXCEPTION_SERVER_DEVICE_FAILURE:
+            return "modbus exception 4: server device failure";
+
+        default:
+            return "unknown error";
+    }
+}
+#endif

modbusino.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <string.h>
 
 
 typedef enum mbsn_error {
@@ -30,6 +31,8 @@ typedef uint8_t mbsn_bitfield[250];
 #define mbsn_bitfield_write(bf, b, v)                                                                                  \
     (((bf)[(b) / 8]) = ((v) ? (((bf)[(b) / 8]) | (0x1 << ((b) % 8))) : (((bf)[(b) / 8]) & ~(0x1 << ((b) % 8)))))
 
+#define mbsn_bitfield_reset(bf) memset(bf, 0, sizeof(mbsn_bitfield))
+
 
 typedef enum mbsn_transport {
     MBSN_TRANSPORT_RTU = 1,
@@ -38,9 +41,10 @@ typedef enum mbsn_transport {
 
 typedef struct mbsn_platform_conf {
     mbsn_transport transport;
-    int (*read_byte)(uint8_t* b, int32_t);
+    int (*read_byte)(uint8_t* b, int32_t, void* arg);
-    int (*write_byte)(uint8_t b, int32_t);
+    int (*write_byte)(uint8_t b, int32_t, void* arg);
-    void (*sleep)(uint32_t milliseconds);
+    void (*sleep)(uint32_t milliseconds, void* arg);
+    void* arg;
 } mbsn_platform_conf;
 
 
@@ -78,6 +82,7 @@ typedef struct mbsn_t {
 
     uint8_t address_rtu;
     uint8_t dest_address_rtu;
+    uint16_t current_tid;
 } mbsn_t;
 
 
@@ -86,8 +91,8 @@ static const uint8_t MBSN_BROADCAST_ADDRESS = 0;
 
 mbsn_error mbsn_client_create(mbsn_t* mbsn, const mbsn_platform_conf* platform_conf);
 
-mbsn_error mbsn_server_create(mbsn_t* mbsn, uint8_t address, const mbsn_platform_conf* platform_conf,
+mbsn_error mbsn_server_create(mbsn_t* mbsn, uint8_t address_rtu, const mbsn_platform_conf* platform_conf,
-                              mbsn_callbacks callbacks);
+                              const mbsn_callbacks* callbacks);
 
 void mbsn_set_read_timeout(mbsn_t* mbsn, int32_t timeout_ms);
 
@@ -95,9 +100,11 @@ void mbsn_set_byte_timeout(mbsn_t* mbsn, int32_t timeout_ms);
 
 void mbsn_set_byte_spacing(mbsn_t* mbsn, uint32_t spacing_ms);
 
+void mbsn_set_platform_arg(mbsn_t* mbsn, void* arg);
+
 void mbsn_set_destination_rtu_address(mbsn_t* mbsn, uint8_t address);
 
-mbsn_error mbsn_server_receive(mbsn_t* mbsn);
+mbsn_error mbsn_server_poll(mbsn_t* mbsn);
 
 mbsn_error mbsn_read_coils(mbsn_t* mbsn, uint16_t address, uint16_t quantity, mbsn_bitfield coils_out);
 
@@ -119,7 +126,9 @@ mbsn_error mbsn_send_raw_pdu(mbsn_t* mbsn, uint8_t fc, const void* data, uint32_
 
 mbsn_error mbsn_receive_raw_pdu_response(mbsn_t* mbsn, void* data_out, uint32_t data_out_len);
 
-const char* mbsn_strerror(int error);
+#ifndef MBSN_STRERROR_DISABLED
+const char* mbsn_strerror(mbsn_error error);
+#endif
 
 
 #endif    //MODBUSINO_H

tests/CMakeLists.txt

@@ -1,14 +0,0 @@
-cmake_minimum_required(VERSION 3.21)
-project(modbusino_tests C)
-
-set(CMAKE_C_STANDARD 99)
-set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -O0 -g")
-set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -O3")
-
-include_directories(. ..)
-
-#add_definitions(-DMBSN_DEBUG)
-
-add_executable(modbusino_tests ../modbusino.c modbusino_tests.c)
-
-target_link_libraries(modbusino_tests pthread)

tests/modbusino_tests.c

@@ -6,12 +6,18 @@
 #include <string.h>
 
 
-int read_byte_empty(uint8_t* b, int32_t timeout) {
+int read_byte_empty(uint8_t* b, int32_t timeout, void* arg) {
+    UNUSED_PARAM(b);
+    UNUSED_PARAM(timeout);
+    UNUSED_PARAM(arg);
     return 0;
 }
 
 
-int write_byte_empty(uint8_t b, int32_t timeout) {
+int write_byte_empty(uint8_t b, int32_t timeout, void* arg) {
+    UNUSED_PARAM(b);
+    UNUSED_PARAM(timeout);
+    UNUSED_PARAM(arg);
     return 0;
 }
 
@@ -25,47 +31,56 @@ void test_server_create(mbsn_transport transport) {
                                               .write_byte = write_byte_empty,
                                               .sleep = platform_sleep};
 
+    mbsn_callbacks callbacks_empty;
+
     should("create a modbus server");
     reset(mbsn);
-    err = mbsn_server_create(&mbsn, TEST_SERVER_ADDR, &platform_conf_empty, (mbsn_callbacks){});
+    err = mbsn_server_create(&mbsn, TEST_SERVER_ADDR, &platform_conf_empty, &callbacks_empty);
     check(err);
 
     should("check parameters and fail to create a modbus server");
     reset(mbsn);
-    err = mbsn_server_create(NULL, TEST_SERVER_ADDR, &platform_conf_empty, (mbsn_callbacks){});
+    err = mbsn_server_create(NULL, TEST_SERVER_ADDR, &platform_conf_empty, &callbacks_empty);
     expect(err == MBSN_ERROR_INVALID_ARGUMENT);
 
     reset(mbsn);
-    err = mbsn_server_create(&mbsn, 0, &platform_conf_empty, (mbsn_callbacks){});
+    err = mbsn_server_create(&mbsn, 0, &platform_conf_empty, &callbacks_empty);
-    expect(err == MBSN_ERROR_INVALID_ARGUMENT);
+    if (transport == MBSN_TRANSPORT_RTU)
+        expect(err == MBSN_ERROR_INVALID_ARGUMENT);
+    else
+        expect(err == MBSN_ERROR_NONE);
 
     reset(mbsn);
     mbsn_platform_conf p = platform_conf_empty;
     p.transport = 3;
-    err = mbsn_server_create(&mbsn, 0, &p, (mbsn_callbacks){});
+    err = mbsn_server_create(&mbsn, 0, &p, &callbacks_empty);
     expect(err == MBSN_ERROR_INVALID_ARGUMENT);
 
     reset(mbsn);
     p = platform_conf_empty;
     p.read_byte = NULL;
-    err = mbsn_server_create(&mbsn, 0, &p, (mbsn_callbacks){});
+    err = mbsn_server_create(&mbsn, 0, &p, &callbacks_empty);
     expect(err == MBSN_ERROR_INVALID_ARGUMENT);
 
     reset(mbsn);
     p = platform_conf_empty;
     p.write_byte = NULL;
-    err = mbsn_server_create(&mbsn, 0, &p, (mbsn_callbacks){});
+    err = mbsn_server_create(&mbsn, 0, &p, &callbacks_empty);
     expect(err == MBSN_ERROR_INVALID_ARGUMENT);
 }
 
 
-int read_byte_timeout(uint8_t* b, int32_t timeout) {
+int read_byte_timeout(uint8_t* b, int32_t timeout, void* arg) {
+    UNUSED_PARAM(b);
+    UNUSED_PARAM(arg);
     usleep(timeout * 1000);
     return 0;
 }
 
 
-int read_byte_timeout_third(uint8_t* b, int32_t timeout) {
+int read_byte_timeout_third(uint8_t* b, int32_t timeout, void* arg) {
+    UNUSED_PARAM(arg);
+
     static int stage = 0;
     switch (stage) {
         case 0:
@@ -89,6 +104,7 @@ void test_server_receive_base(mbsn_transport transport) {
     mbsn_t server, client;
     mbsn_error err;
     mbsn_platform_conf platform_conf;
+    mbsn_callbacks callbacks_empty;
 
 
     should("honor read_timeout and return normally");
@@ -100,7 +116,7 @@ void test_server_receive_base(mbsn_transport transport) {
 
     const int32_t read_timeout_ms = 250;
 
-    err = mbsn_server_create(&server, TEST_SERVER_ADDR, &platform_conf, (mbsn_callbacks){});
+    err = mbsn_server_create(&server, TEST_SERVER_ADDR, &platform_conf, &callbacks_empty);
     check(err);
 
     mbsn_set_read_timeout(&server, read_timeout_ms);
@@ -109,12 +125,12 @@ void test_server_receive_base(mbsn_transport transport) {
     const int polls = 5;
     for (int i = 0; i < polls; i++) {
         uint64_t start = now_ms();
-        err = mbsn_server_receive(&server);
+        err = mbsn_server_poll(&server);
         check(err);
 
         uint64_t diff = now_ms() - start;
 
-        assert(diff >= read_timeout_ms);
+        assert(diff >= (uint64_t) read_timeout_ms);
     }
 
 
@@ -126,13 +142,13 @@ void test_server_receive_base(mbsn_transport transport) {
 
     const int32_t byte_timeout_ms = 250;
 
-    err = mbsn_server_create(&server, TEST_SERVER_ADDR, &platform_conf, (mbsn_callbacks){});
+    err = mbsn_server_create(&server, TEST_SERVER_ADDR, &platform_conf, &callbacks_empty);
     check(err);
 
     mbsn_set_read_timeout(&server, 1000);
     mbsn_set_byte_timeout(&server, byte_timeout_ms);
 
-    err = mbsn_server_receive(&server);
+    err = mbsn_server_poll(&server);
     expect(err == MBSN_ERROR_TIMEOUT);
 
 
@@ -193,15 +209,16 @@ mbsn_error read_discrete(uint16_t address, uint16_t quantity, mbsn_bitfield coil
 void test_fc1(mbsn_transport transport) {
     const uint8_t fc = 1;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_read_coils(&CLIENT, 0, 1, NULL) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.read_coils = read_discrete});
+    start_client_and_server(transport, &(mbsn_callbacks){.read_coils = read_discrete});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_read_coils(&CLIENT, 1, 0, NULL) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -259,15 +276,16 @@ void test_fc1(mbsn_transport transport) {
 void test_fc2(mbsn_transport transport) {
     const uint8_t fc = 2;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_read_discrete_inputs(&CLIENT, 0, 1, NULL) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.read_discrete_inputs = read_discrete});
+    start_client_and_server(transport, &(mbsn_callbacks){.read_discrete_inputs = read_discrete});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_read_discrete_inputs(&CLIENT, 1, 0, NULL) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -345,15 +363,16 @@ mbsn_error read_registers(uint16_t address, uint16_t quantity, uint16_t* registe
 void test_fc3(mbsn_transport transport) {
     const uint8_t fc = 3;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_read_holding_registers(&CLIENT, 0, 1, NULL) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.read_holding_registers = read_registers});
+    start_client_and_server(transport, &(mbsn_callbacks){.read_holding_registers = read_registers});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_read_holding_registers(&CLIENT, 1, 0, NULL) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -399,15 +418,16 @@ void test_fc3(mbsn_transport transport) {
 void test_fc4(mbsn_transport transport) {
     const uint8_t fc = 4;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_read_input_registers(&CLIENT, 0, 1, NULL) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.read_input_registers = read_registers});
+    start_client_and_server(transport, &(mbsn_callbacks){.read_input_registers = read_registers});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_read_input_registers(&CLIENT, 1, 0, NULL) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -473,15 +493,16 @@ mbsn_error write_coil(uint16_t address, bool value) {
 void test_fc5(mbsn_transport transport) {
     const uint8_t fc = 5;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_write_single_coil(&CLIENT, 0, true) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.write_single_coil = write_coil});
+    start_client_and_server(transport, &(mbsn_callbacks){.write_single_coil = write_coil});
 
     should("return MBSN_EXCEPTION_ILLEGAL_DATA_VALUE when calling with value !0x0000 or 0xFF000");
     check(mbsn_send_raw_pdu(&CLIENT, fc, (uint16_t[]){htons(6), htons(0x0001)}, 4));
@@ -537,15 +558,16 @@ mbsn_error write_register(uint16_t address, uint16_t value) {
 void test_fc6(mbsn_transport transport) {
     const uint8_t fc = 6;
     uint8_t raw_res[260];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_write_single_register(&CLIENT, 0, 123) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.write_single_register = write_register});
+    start_client_and_server(transport, &(mbsn_callbacks){.write_single_register = write_register});
 
     should("return MBSN_EXCEPTION_SERVER_DEVICE_FAILURE when server handler returns any non-exception error");
     assert(mbsn_write_single_register(&CLIENT, 1, 123) == MBSN_EXCEPTION_SERVER_DEVICE_FAILURE);
@@ -617,15 +639,16 @@ void test_fc15(mbsn_transport transport) {
     const uint8_t fc = 15;
     uint8_t raw_res[260];
     mbsn_bitfield bf = {0};
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_write_multiple_coils(&CLIENT, 0, 1, bf) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.write_multiple_coils = write_coils});
+    start_client_and_server(transport, &(mbsn_callbacks){.write_multiple_coils = write_coils});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_write_multiple_coils(&CLIENT, 1, 0, bf) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -730,15 +753,16 @@ void test_fc16(mbsn_transport transport) {
     const uint8_t fc = 16;
     uint8_t raw_res[260];
     uint16_t registers[125];
+    mbsn_callbacks callbacks_empty = {0};
 
-    start_client_and_server(transport, (mbsn_callbacks){});
+    start_client_and_server(transport, &callbacks_empty);
 
     should("return MBSN_EXCEPTION_ILLEGAL_FUNCTION when callback is not registered server-side");
     assert(mbsn_write_multiple_registers(&CLIENT, 0, 1, registers) == MBSN_EXCEPTION_ILLEGAL_FUNCTION);
 
     stop_client_and_server();
 
-    start_client_and_server(transport, (mbsn_callbacks){.write_multiple_registers = write_registers});
+    start_client_and_server(transport, &(mbsn_callbacks){.write_multiple_registers = write_registers});
 
     should("immediately return MBSN_ERROR_INVALID_ARGUMENT when calling with quantity 0");
     assert(mbsn_write_multiple_registers(&CLIENT, 1, 0, registers) == MBSN_ERROR_INVALID_ARGUMENT);
@@ -801,7 +825,7 @@ mbsn_transport transports[2] = {MBSN_TRANSPORT_RTU, MBSN_TRANSPORT_TCP};
 const char* transports_str[2] = {"RTU", "TCP"};
 
 void for_transports(void (*test_fn)(mbsn_transport), const char* should_str) {
-    for (int t = 0; t < sizeof(transports) / sizeof(mbsn_transport); t++) {
+    for (unsigned long t = 0; t < sizeof(transports) / sizeof(mbsn_transport); t++) {
         printf("Should %s on %s:\n", should_str, transports_str[t]);
         test(test_fn(transports[t]));
     }

tests/modbusino_tests.h

@@ -16,10 +16,8 @@
 
 #define test(f) (nesting++, (f), nesting--)
 
-/*
+#define UNUSED_PARAM(x) ((x) = (x))
-#define htons(w) (((((uint16_t) (w) &0xFF)) << 8) | (((uint16_t) (w) &0xFF00) >> 8))
+
-#define ntohs(w) (((((uint16_t) (w) &0xFF)) << 8) | (((uint16_t) (w) &0xFF00) >> 8))
-*/
 
 const uint8_t TEST_SERVER_ADDR = 1;
 
@@ -35,7 +33,7 @@ mbsn_t CLIENT, SERVER;
 
 
 #define should(s)                                                                                                      \
-    for (int i = 0; i < nesting; i++) {                                                                                \
+    for (unsigned int i = 0; i < nesting; i++) {                                                                       \
         printf("\t");                                                                                                  \
     }                                                                                                                  \
     printf("Should %s\n", (s))
@@ -48,7 +46,8 @@ uint64_t now_ms() {
 }
 
 
-void platform_sleep(uint32_t milliseconds) {
+void platform_sleep(uint32_t milliseconds, void* arg) {
+    UNUSED_PARAM(arg);
     usleep(milliseconds * 1000);
 }
 
@@ -124,22 +123,26 @@ int write_byte_fd(int fd, uint8_t b, int32_t timeout_ms) {
 }
 
 
-int read_byte_socket_server(uint8_t* b, int32_t timeout_ms) {
+int read_byte_socket_server(uint8_t* b, int32_t timeout_ms, void* arg) {
+    UNUSED_PARAM(arg);
     return read_byte_fd(sockets[0], b, timeout_ms);
 }
 
 
-int write_byte_socket_server(uint8_t b, int32_t timeout_ms) {
+int write_byte_socket_server(uint8_t b, int32_t timeout_ms, void* arg) {
+    UNUSED_PARAM(arg);
     return write_byte_fd(sockets[0], b, timeout_ms);
 }
 
 
-int read_byte_socket_client(uint8_t* b, int32_t timeout_ms) {
+int read_byte_socket_client(uint8_t* b, int32_t timeout_ms, void* arg) {
+    UNUSED_PARAM(arg);
     return read_byte_fd(sockets[1], b, timeout_ms);
 }
 
 
-int write_byte_socket_client(uint8_t b, int32_t timeout_ms) {
+int write_byte_socket_client(uint8_t b, int32_t timeout_ms, void* arg) {
+    UNUSED_PARAM(arg);
     return write_byte_fd(sockets[1], b, timeout_ms);
 }
 
@@ -178,7 +181,7 @@ void* server_listen_thread() {
         if (is_server_listen_thread_stopped())
             break;
 
-        check(mbsn_server_receive(&SERVER));
+        check(mbsn_server_poll(&SERVER));
     }
 
     return NULL;
@@ -195,7 +198,7 @@ void stop_client_and_server() {
 }
 
 
-void start_client_and_server(mbsn_transport transport, mbsn_callbacks server_callbacks) {
+void start_client_and_server(mbsn_transport transport, const mbsn_callbacks* server_callbacks) {
     assert(pthread_mutex_destroy(&server_stopped_m) == 0);
     assert(pthread_mutex_init(&server_stopped_m, NULL) == 0);