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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1 | pmbaty | 1 | // Modbus TCP client by Pierre-Marie Baty <pm@pmbaty.com> |
| 2 | |||
| 3 | #include <stdio.h> |
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| 4 | #include <stdlib.h> |
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| 5 | #include <stdint.h> |
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| 6 | #include <limits.h> |
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| 7 | #include <string.h> |
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| 8 | #include <errno.h> |
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| 9 | #include <time.h> |
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| 10 | #ifdef _WIN32 // POSIX shims for that Microsoft joke pretending to be an OS |
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| 11 | typedef ptrdiff_t ssize_t; |
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| 12 | static const char *basename (const char *pathname) |
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| 13 | { |
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| 14 | for (const char *p = pathname + strlen (pathname); p != pathname; p--) |
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| 15 | if ((*p == '\\') || (*p == '/')) |
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| 16 | return (p + 1); |
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| 17 | return (pathname); |
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| 18 | } |
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| 19 | #define fputc SetConsoleOutputCP(CP_UTF8), fputc |
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| 20 | #define fputs SetConsoleOutputCP(CP_UTF8), fputs |
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| 21 | #define printf SetConsoleOutputCP(CP_UTF8), printf |
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| 22 | #define fprintf SetConsoleOutputCP(CP_UTF8), fprintf |
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| 23 | #include <winsock2.h> |
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| 24 | static int _socket (int domain, int type, int protocol) |
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| 25 | { |
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| 26 | static WSADATA wsa_data = { 0 }; |
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| 27 | if (wsa_data.wVersion == 0) |
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| 28 | WSAStartup (0x0202, &wsa_data); |
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| 29 | return (socket (domain, type, protocol)); |
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| 30 | } |
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| 31 | #define socket(domain,type,protocol) _socket ((domain), (type), (protocol)) |
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| 32 | #ifdef _MSC_VER |
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| 33 | #pragma comment(lib,"ws2_32.lib") |
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| 34 | #endif // _MSC_VER |
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| 35 | #else // !_WIN32 |
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| 36 | #include <libgen.h> |
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| 37 | #include <sys/socket.h> |
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| 38 | #include <netinet/in.h> |
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| 39 | #include <arpa/inet.h> |
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| 40 | #endif // _WIN32 |
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| 41 | |||
| 42 | |||
| 43 | int main (int argc, char **argv) |
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| 44 | { |
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| 45 | const char *modbus_function_strings[] = |
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| 46 | { |
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| 47 | "", // not defined |
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| 48 | "Read Coils", |
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| 49 | "Read Discrete Inputs", |
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| 50 | "Read Multiple Holding Registers", |
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| 51 | "Read Input Registers", |
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| 52 | "Write Single Coil", |
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| 53 | "Write Single Holding Register", |
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| 54 | "Read Exception Status [serial only]", // serial only |
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| 55 | "Diagnostic [serial only]", // serial only |
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| 56 | "", // not defined |
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| 57 | "", // not defined |
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| 58 | "Get Com Event Counter [serial only]", // serial only |
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| 59 | "Get Com Event Log [serial only]", // serial only |
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| 60 | "", // not defined |
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| 61 | "", // not defined |
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| 62 | "Write Multiple Coils", |
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| 63 | "Write Multiple Holding Registers", |
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| 64 | }; |
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| 65 | const char *modbus_exception_strings[] = |
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| 66 | { |
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| 67 | "undefined exception", // not defined |
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| 68 | "Illegal Function", |
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| 69 | "Illegal Data Address", |
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| 70 | "Illegal Data Value", |
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| 71 | "Server Device Failure", |
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| 72 | "Acknowledge", |
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| 73 | "Server Device Busy", |
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| 74 | "Negative Acknowledge", |
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| 75 | "Memory Parity Error", |
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| 76 | "undefined exception", // not defined |
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| 77 | "Gateway Path Unavailable", |
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| 78 | "Gateway Target Device Failed to Respond", |
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| 79 | }; |
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| 80 | |||
| 81 | struct sockaddr_in server = { 0 }; |
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| 82 | unsigned int address_bytes[4] = { 0 }; |
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| 83 | unsigned int port = 502; |
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| 84 | #ifdef _MSC_VER |
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| 85 | #pragma pack(push,1) |
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| 86 | #define __attribute__(...) |
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| 87 | #endif // _MSC_VER |
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| 88 | struct __attribute__((packed)) |
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| 89 | { |
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| 90 | struct __attribute__((packed)) |
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| 91 | { |
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| 92 | uint16_t message_id; // big endian |
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| 93 | uint16_t protocol_id; // big endian |
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| 94 | uint16_t payload_len; // big endian |
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| 95 | uint8_t unit_id; |
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| 96 | } header; |
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| 97 | union |
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| 98 | { |
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| 99 | struct __attribute__((packed)) |
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| 100 | { |
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| 101 | uint8_t function_code; |
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| 102 | uint16_t start_address; // big endian |
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| 103 | uint16_t count_or_val; // big endian |
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| 104 | uint8_t byte_len; // optional |
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| 105 | uint8_t bytes[UINT8_MAX]; // optional |
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| 106 | } as_query; |
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| 107 | struct __attribute__((packed)) |
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| 108 | { |
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| 109 | uint8_t function_code; |
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| 110 | union |
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| 111 | { |
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| 112 | struct __attribute__((packed)) |
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| 113 | { |
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| 114 | uint8_t byte_len; |
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| 115 | uint8_t bytes[UINT8_MAX]; |
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| 116 | } as_bytelen_plus_data; // function codes 1-4 |
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| 117 | struct __attribute__((packed)) |
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| 118 | { |
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| 119 | uint16_t start_address; |
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| 120 | uint16_t count_or_val; |
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| 121 | } as_address_plus_value; // function codes 5-6 |
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| 122 | struct __attribute__((packed)) |
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| 123 | { |
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| 124 | uint8_t bytes[0xffff]; |
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| 125 | } as_data; // unknown function codes |
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| 126 | } u; |
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| 127 | } as_reply; |
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| 128 | struct __attribute__((packed)) |
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| 129 | { |
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| 130 | uint8_t function_code; |
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| 131 | uint8_t exception_code; |
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| 132 | } as_error; |
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| 133 | } u; |
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| 134 | } modbus_message = { 0 }; |
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| 135 | #ifdef _MSC_VER |
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| 136 | #undef __attribute__ |
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| 137 | #pragma pack(pop) |
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| 138 | #endif // _MSC_VER |
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| 139 | ssize_t message_len; |
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| 140 | size_t array_index; |
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| 141 | int client_socket; |
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| 142 | |||
| 143 | if (argc < 6) |
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| 144 | { |
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| 145 | fputs ("usage:\n", stderr); |
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| 146 | fprintf (stderr, " %s <ip address[:port]> <unit ID> <function code> <start address> <count|value> [<hexbyte> [...]]\n", basename (argv[0])); |
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| 147 | fputs ("Modbus function codes:\n", stderr); |
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| 148 | for (array_index = 0; array_index < sizeof (modbus_function_strings) / sizeof (modbus_function_strings[0]); array_index++) |
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| 149 | if ((modbus_function_strings[array_index][0] != 0) && (strstr (modbus_function_strings[array_index], " [serial only]") == NULL)) |
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| 150 | fprintf (stderr, " %zd\t%s\n", array_index, modbus_function_strings[array_index]); |
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| 151 | exit (1); |
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| 152 | } |
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| 153 | |||
| 154 | if ((sscanf (argv[1], "%u.%u.%u.%u:%u", &address_bytes[0], &address_bytes[1], &address_bytes[2], &address_bytes[3], &port) < 4) |
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| 155 | || ((address_bytes[0] | address_bytes[1] | address_bytes[2] | address_bytes[3]) > 255)) |
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| 156 | { |
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| 157 | fprintf (stderr, "error: invalid IPv4 address\n"); |
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| 158 | exit (1); |
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| 159 | } |
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| 160 | server.sin_family = AF_INET; |
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| 161 | server.sin_addr.s_addr = htonl ((address_bytes[0] << 24) | (address_bytes[1] << 16) | (address_bytes[2] << 8) | (address_bytes[3] << 0)); |
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| 162 | server.sin_port = htons ((uint16_t) port); |
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| 163 | |||
| 164 | client_socket = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP); |
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| 165 | if (client_socket == -1) |
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| 166 | { |
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| 167 | fprintf (stderr, "error: socket() call failed with errno %d: %s\n", errno, strerror (errno)); |
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| 168 | exit (1); |
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| 169 | } |
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| 170 | else if (connect (client_socket, (struct sockaddr *) &server, sizeof (server)) == -1) |
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| 171 | { |
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| 172 | fprintf (stderr, "error: connect() call failed with errno %d: %s\n", errno, strerror (errno)); |
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| 173 | exit (1); |
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| 174 | } |
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| 175 | printf ("Connected to %u.%u.%u.%u on port %u\n", address_bytes[0], address_bytes[1], address_bytes[2], address_bytes[3], port); |
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| 176 | |||
| 177 | srand (time (NULL)); |
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| 178 | modbus_message.header.message_id = ntohs ((uint16_t) rand ()); |
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| 179 | modbus_message.header.protocol_id = ntohs (0); |
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| 180 | modbus_message.header.unit_id = (uint8_t) strtol (argv[2], NULL, 0); |
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| 181 | modbus_message.u.as_query.function_code = (uint8_t) strtol (argv[3], NULL, 0); |
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| 182 | modbus_message.u.as_query.start_address = ntohs ((uint16_t) strtol (argv[4], NULL, 0)); |
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| 183 | modbus_message.u.as_query.count_or_val = ntohs ((uint16_t) strtol (argv[5], NULL, 0)); |
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| 184 | modbus_message.u.as_query.byte_len = 0; |
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| 185 | for (array_index = 6; array_index < argc; array_index++) |
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| 186 | modbus_message.u.as_query.bytes[modbus_message.u.as_query.byte_len++] = (uint8_t) strtol (argv[array_index], NULL, 0); |
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| 187 | |||
| 188 | message_len = sizeof (modbus_message.header) + sizeof (modbus_message.u.as_query.function_code); |
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| 189 | if (strchr ("\x01\x02\x03\x04\x05\x06", (char) modbus_message.u.as_query.function_code) != NULL) |
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| 190 | message_len += sizeof (modbus_message.u.as_query.start_address) + sizeof (modbus_message.u.as_query.count_or_val); |
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| 191 | else if (modbus_message.u.as_query.byte_len > 0) |
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| 192 | message_len += sizeof (modbus_message.u.as_query.start_address) + sizeof (modbus_message.u.as_query.count_or_val) + sizeof (modbus_message.u.as_query.byte_len) + modbus_message.u.as_query.byte_len; |
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| 193 | modbus_message.header.payload_len = ntohs (message_len - ((size_t) &modbus_message.header.unit_id - (size_t) &modbus_message)); |
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| 194 | |||
| 195 | fputs ("Modbus query:", stdout); |
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| 196 | for (array_index = 0; array_index < message_len; array_index++) |
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| 197 | printf (" %02x", ((uint8_t *) &modbus_message)[array_index]); |
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| 198 | fputc ('\n', stdout); |
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| 199 | fputs ("├ MBAP header\n", stdout); |
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| 200 | printf ("│ ├ Message ID: %d\n", ntohs (modbus_message.header.message_id)); |
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| 201 | printf ("│ ├ Protocol ID: %d\n", ntohs (modbus_message.header.protocol_id)); |
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| 202 | printf ("│ ├ Payload length: %d bytes\n", ntohs (modbus_message.header.payload_len)); |
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| 203 | printf ("│ └ Unit ID: %d\n", modbus_message.header.unit_id); |
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| 204 | fputs ("└ Payload\n", stdout); |
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| 205 | if (message_len == sizeof (modbus_message.header) + sizeof (modbus_message.u.as_query.function_code)) |
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| 206 | printf (" └ Function code: %d (%s)\n", modbus_message.u.as_query.function_code, (modbus_message.u.as_query.function_code < sizeof (modbus_function_strings) / sizeof (modbus_function_strings[0]) ? modbus_function_strings[modbus_message.u.as_query.function_code] : "unknown function code")); |
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| 207 | else |
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| 208 | { |
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| 209 | printf (" ├ Function code: %d (%s)\n", modbus_message.u.as_query.function_code, (modbus_message.u.as_query.function_code < sizeof (modbus_function_strings) / sizeof (modbus_function_strings[0]) ? modbus_function_strings[modbus_message.u.as_query.function_code] : "unknown function code")); |
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| 210 | printf (" ├ Start address: %d\n", ntohs (modbus_message.u.as_query.start_address)); |
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| 211 | if (message_len == sizeof (modbus_message.header) + sizeof (modbus_message.u.as_query.function_code) + sizeof (modbus_message.u.as_query.start_address) + sizeof (modbus_message.u.as_query.count_or_val)) |
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| 212 | printf (" └ Count / value: %d\n", ntohs (modbus_message.u.as_query.count_or_val)); |
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| 213 | else |
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| 214 | { |
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| 215 | printf (" ├ Count / value: %d\n", ntohs (modbus_message.u.as_query.count_or_val)); |
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| 216 | printf (" ├ Data length: %d bytes\n", modbus_message.u.as_query.byte_len); |
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| 217 | fputs (" └ Data: ", stdout); |
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| 218 | for (array_index = 0; array_index < modbus_message.u.as_query.byte_len; array_index++) |
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| 219 | printf (" %02x", modbus_message.u.as_query.bytes[array_index]); |
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| 220 | fputc ('\n', stdout); |
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| 221 | } |
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| 222 | } |
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| 223 | |||
| 224 | if (send (client_socket, (void *) &modbus_message, message_len, 0) != message_len) |
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| 225 | { |
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| 226 | fprintf (stderr, "error: send() call failed with errno %d: %s\n", errno, strerror (errno)); |
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| 227 | exit (1); |
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| 228 | } |
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| 229 | |||
| 230 | message_len = recv (client_socket, (void *) &modbus_message, sizeof (modbus_message), 0); |
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| 231 | if (message_len <= 0) |
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| 232 | { |
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| 233 | fprintf (stderr, "error: recv() call failed with return value %zd and errno %d: %s\n", message_len, errno, strerror (errno)); |
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| 234 | exit (1); |
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| 235 | } |
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| 236 | |||
| 237 | fputs ("Modbus reply:", stdout); |
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| 238 | for (array_index = 0; array_index < message_len; array_index++) |
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| 239 | printf (" %02x", ((uint8_t *) &modbus_message)[array_index]); |
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| 240 | fputc ('\n', stdout); |
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| 241 | printf ("├ MBAP header\n"); |
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| 242 | printf ("│ ├ Message ID: %d\n", ntohs (modbus_message.header.message_id)); |
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| 243 | printf ("│ ├ Protocol ID: %d\n", ntohs (modbus_message.header.protocol_id)); |
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| 244 | printf ("│ ├ Payload length: %d bytes\n", ntohs (modbus_message.header.payload_len)); |
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| 245 | printf ("│ └ Unit ID: %d\n", modbus_message.header.unit_id); |
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| 246 | printf ("└ Payload\n"); |
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| 247 | printf (" ├ Function code: %d (%s)\n", modbus_message.u.as_reply.function_code & 0x7f, (modbus_message.u.as_reply.function_code & 0x80 ? "error bit set" : "ok")); |
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| 248 | if (modbus_message.u.as_reply.function_code & 0x80) |
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| 249 | printf (" └ Exception code: %d (%s)\n", modbus_message.u.as_error.exception_code, (modbus_message.u.as_error.exception_code < sizeof (modbus_exception_strings) / sizeof (modbus_exception_strings[0]) ? modbus_exception_strings[modbus_message.u.as_error.exception_code] : "unknown exception")); |
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| 250 | else if ((modbus_message.u.as_reply.function_code >= 1) && (modbus_message.u.as_reply.function_code <= 4)) |
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| 251 | { |
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| 252 | printf (" ├ Data length: %d bytes\n", modbus_message.u.as_reply.u.as_bytelen_plus_data.byte_len); |
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| 253 | fputs (" └ Data: ", stdout); |
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| 254 | for (array_index = 0; array_index < modbus_message.u.as_reply.u.as_bytelen_plus_data.byte_len; array_index++) |
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| 255 | printf (" %02x", modbus_message.u.as_reply.u.as_bytelen_plus_data.bytes[array_index]); |
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| 256 | fputc ('\n', stdout); |
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| 257 | } |
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| 258 | else if ( ((modbus_message.u.as_reply.function_code >= 4) && (modbus_message.u.as_reply.function_code <= 5)) |
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| 259 | || ((modbus_message.u.as_reply.function_code >= 15) && (modbus_message.u.as_reply.function_code <= 16))) |
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| 260 | { |
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| 261 | printf (" ├ Start address: %d\n", modbus_message.u.as_reply.u.as_address_plus_value.start_address); |
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| 262 | printf (" └ Count / value: %d\n", modbus_message.u.as_reply.u.as_address_plus_value.count_or_val); |
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| 263 | } |
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| 264 | else |
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| 265 | { |
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| 266 | fputs (" └ Data: ", stdout); |
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| 267 | for (array_index = 0; array_index < message_len - ((size_t) modbus_message.u.as_reply.u.as_data.bytes - (size_t) &modbus_message); array_index++) |
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| 268 | printf (" %02x", modbus_message.u.as_reply.u.as_data.bytes[array_index]); |
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| 269 | fputc ('\n', stdout); |
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| 270 | } |
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| 271 | |||
| 272 | exit (modbus_message.u.as_reply.function_code & 0x80 ? 1 : 0); |
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| 273 | } |