Added modbus encapsulated in TCP support.

src/Makefile.am

@@ -20,7 +20,9 @@ libmodbus_la_SOURCES = \
         modbus-tcp.c \
         modbus-tcp.h \
         modbus-tcp-private.h \
-        modbus-version.h
+        modbus-version.h \
+        modbus-enc.c \
+        modbus-enc.h
 
 libmodbus_la_LDFLAGS = -no-undefined \
         -version-info $(LIBMODBUS_LT_VERSION_INFO)
@@ -35,7 +37,7 @@ endif
 
 # Header files to install
 libmodbusincludedir = $(includedir)/modbus
-libmodbusinclude_HEADERS = modbus.h modbus-version.h modbus-rtu.h modbus-tcp.h
+libmodbusinclude_HEADERS = modbus.h modbus-version.h modbus-rtu.h modbus-tcp.h modbus-enc.h
 
 DISTCLEANFILES = modbus-version.h
 EXTRA_DIST += modbus-version.h.in

src/modbus-enc.c

@@ -0,0 +1,265 @@
+#include "modbus-enc.h"
+
+#include "modbus.h"
+#include "modbus-private.h"
+#include "modbus-tcp.h"
+#include "modbus-rtu.h"
+#include "modbus-rtu-private.h"
+#include "modbus-tcp-private.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+/* Table of CRC values for high-order byte */
+static const uint8_t table_crc_hi[] = {
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
+    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
+    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
+    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
+    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
+    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
+    0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
+    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
+    0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
+    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
+    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
+    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
+    0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
+    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
+    0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
+};
+
+/* Table of CRC values for low-order byte */
+static const uint8_t table_crc_lo[] = {
+    0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
+    0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
+    0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
+    0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
+    0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
+    0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
+    0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
+    0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
+    0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
+    0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
+    0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
+    0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
+    0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
+    0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
+    0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
+    0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
+    0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
+    0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
+    0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
+    0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
+    0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
+    0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
+    0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
+    0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
+    0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
+    0x43, 0x83, 0x41, 0x81, 0x80, 0x40
+};
+
+
+static modbus_t* get_rtu_ctx(modbus_t* ctx)
+{
+    return ((modbus_t**)(ctx->backend_data))[0];
+}
+
+static modbus_t* get_tcp_ctx(modbus_t* ctx)
+{
+    return ((modbus_t**)(ctx->backend_data))[1];
+}
+
+static int _modbus_enc_set_slave(modbus_t *ctx, int slave)
+{
+    modbus_t* ctx_rtu = get_rtu_ctx(ctx);
+
+    return ctx_rtu->backend->set_slave(ctx_rtu, slave);
+}
+
+static int _modbus_enc_build_request_basis(modbus_t *ctx, int function,
+                                           int addr, int nb,
+                                           uint8_t *req)
+{
+    modbus_t* ctx_rtu = get_rtu_ctx(ctx);
+
+    return ctx_rtu->backend->build_request_basis(ctx_rtu, function, addr, nb, req);
+}
+
+static int _modbus_enc_build_response_basis(sft_t *sft, uint8_t *rsp)
+{
+    /* In this case, the slave is certainly valid because a check is already
+     * done in _modbus_rtu_listen */
+    rsp[0] = sft->slave;
+    rsp[1] = sft->function;
+
+    return _MODBUS_RTU_PRESET_RSP_LENGTH;
+}
+
+static int _modbus_enc_prepare_response_tid(const uint8_t *req, int *req_length)
+{
+    (*req_length) -= _MODBUS_RTU_CHECKSUM_LENGTH;
+    /* No TID */
+    return 0;
+}
+
+static uint16_t crc16(uint8_t *buffer, uint16_t buffer_length)
+{
+    uint8_t crc_hi = 0xFF; /* high CRC byte initialized */
+    uint8_t crc_lo = 0xFF; /* low CRC byte initialized */
+    unsigned int i; /* will index into CRC lookup */
+
+    /* pass through message buffer */
+    while (buffer_length--) {
+        i = crc_hi ^ *buffer++; /* calculate the CRC  */
+        crc_hi = crc_lo ^ table_crc_hi[i];
+        crc_lo = table_crc_lo[i];
+    }
+
+    return (crc_hi << 8 | crc_lo);
+}
+
+static int _modbus_enc_send_msg_pre(uint8_t *req, int req_length)
+{
+    uint16_t crc = crc16(req, req_length);
+    req[req_length++] = crc >> 8;
+    req[req_length++] = crc & 0x00FF;
+
+    return req_length;
+}
+
+static int _modbus_enc_check_integrity(modbus_t *ctx, uint8_t *msg,
+                                       const int msg_length)
+{
+    modbus_t* ctx_rtu = get_rtu_ctx(ctx);
+
+    return ctx_rtu->backend->check_integrity(ctx_rtu, msg, msg_length);
+}
+
+static int _modbus_enc_pre_check_confirmation(modbus_t *ctx, const uint8_t *req,
+                                              const uint8_t *rsp, int rsp_length)
+{
+    modbus_t* ctx_rtu = get_rtu_ctx(ctx);
+
+    return ctx_rtu->backend->pre_check_confirmation(ctx_rtu, req, rsp, rsp_length);
+}
+
+static int _modbus_enc_connect(modbus_t *ctx)
+{
+    int ret;
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    ret = ctx_tcp->backend->connect(ctx_tcp);
+    ctx->s = ctx_tcp->s;
+    return ret;
+}
+
+static void _modbus_enc_close(modbus_t *ctx)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->close(ctx_tcp);
+}
+
+static int _modbus_enc_flush(modbus_t *ctx)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->flush(ctx_tcp);
+}
+
+static void _modbus_enc_free(modbus_t *ctx)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+    modbus_t* ctx_rtu = get_rtu_ctx(ctx);
+
+    modbus_free(ctx_tcp);
+    modbus_free(ctx_rtu);
+
+    free(ctx->backend_data);
+    free(ctx);
+}
+
+static ssize_t _modbus_enc_send(modbus_t *ctx, const uint8_t *req, int req_length)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->send(ctx_tcp, req, req_length);
+}
+
+static int _modbus_enc_receive(modbus_t *ctx, uint8_t *req)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->receive(ctx_tcp, req);
+}
+
+static ssize_t _modbus_enc_recv(modbus_t *ctx, uint8_t *rsp, int rsp_length)
+{
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->recv(ctx_tcp, rsp, rsp_length);
+}
+
+static int _modbus_enc_select(modbus_t *ctx, fd_set *rset, struct timeval *tv, int length_to_read) {
+    modbus_t* ctx_tcp = get_tcp_ctx(ctx);
+
+    return ctx_tcp->backend->select(ctx_tcp, rset, tv, length_to_read);
+}
+
+
+extern const modbus_backend_t _modbus_rtu_backend;
+extern const modbus_backend_t _modbus_tcp_backend;
+
+modbus_backend_t _modbus_enc_backend = {
+    _MODBUS_BACKEND_TYPE_RTU,
+    _MODBUS_RTU_HEADER_LENGTH,
+    _MODBUS_RTU_CHECKSUM_LENGTH,
+    MODBUS_RTU_MAX_ADU_LENGTH,
+    _modbus_enc_set_slave,
+    _modbus_enc_build_request_basis,
+    _modbus_enc_build_response_basis,
+    _modbus_enc_prepare_response_tid,
+    _modbus_enc_send_msg_pre,
+    _modbus_enc_send,
+    _modbus_enc_receive,
+    _modbus_enc_recv,
+    _modbus_enc_check_integrity,
+    _modbus_enc_pre_check_confirmation,
+    _modbus_enc_connect,
+    _modbus_enc_close,
+    _modbus_enc_flush,
+    _modbus_enc_select,
+    _modbus_enc_free
+};
+
+
+modbus_t* modbus_new_enc(const char *ip_address, int port)
+{
+    modbus_t* ctx;
+    modbus_t* ctx_rtu = modbus_new_rtu("/tmp", 115200, 'N', 8, 1);
+    modbus_t* ctx_tcp = modbus_new_tcp(ip_address, port);
+    modbus_t** data;
+
+    ctx = (modbus_t *)malloc(sizeof(modbus_t));
+    data = malloc(2*sizeof(modbus_t*));
+
+    data[0] = ctx_rtu;
+    data[1] = ctx_tcp;
+
+    ctx->backend = &_modbus_enc_backend;
+    ctx->backend_data = data;
+
+    return ctx;
+}

src/modbus-enc.h

@@ -0,0 +1,12 @@
+#ifndef MODBUS_ENC_H
+#define MODBUS_ENC_H
+
+#include "modbus.h"
+
+MODBUS_BEGIN_DECLS
+
+MODBUS_API modbus_t* modbus_new_enc(const char *ip_address, int port);
+
+MODBUS_END_DECLS
+
+#endif /* MODBUS_ENC_H */

src/modbus.h

@@ -284,6 +284,7 @@ MODBUS_API void modbus_set_float_cdab(float f, uint16_t *dest);
 
 #include "modbus-tcp.h"
 #include "modbus-rtu.h"
+#include "modbus-enc.h"
 
 MODBUS_END_DECLS