diff -r 000000000000 -r ae252e0fd9b8 mb_slave.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/mb_slave.c Sun Mar 05 00:05:46 2017 +0000
@@ -0,0 +1,845 @@
+/*
+ * Copyright (c) 2001,2016 Mario de Sousa (msousa@fe.up.pt)
+ *
+ * This file is part of the Modbus library for Beremiz and matiec.
+ *
+ * This Modbus library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this Modbus library. If not, see .
+ *
+ * This code is made available on the understanding that it will not be
+ * used in safety-critical situations without a full and competent review.
+ */
+
+
+/* mb_slave.c */
+
+#include /* File control definitions */
+#include /* Standard input/output */
+#include
+#include
+#include /* POSIX terminal control definitions */
+#include /* Time structures for select() */
+#include /* POSIX Symbolic Constants */
+#include /* Error definitions */
+
+#include /* required for htons() and ntohs() */
+#include "mb_layer1.h"
+#include "mb_slave.h"
+#include "mb_slave_private.h"
+
+/* #define DEBUG */ /* uncomment to see the data sent and received */
+
+
+#define modbus_write fptr_[layer1_fin].modbus_write
+#define modbus_read fptr_[layer1_fin].modbus_read
+#define modbus_init fptr_[layer1_fin].modbus_init
+#define modbus_done fptr_[layer1_fin].modbus_done
+#define modbus_connect fptr_[layer1_fin].modbus_connect
+#define modbus_listen fptr_[layer1_fin].modbus_listen
+#define modbus_close fptr_[layer1_fin].modbus_close
+#define modbus_silence_init fptr_[layer1_fin].modbus_silence_init
+#define modbus_get_min_timeout fptr_[layer1_fin].modbus_get_min_timeout
+
+/* the lower two bits of ttyfd are used to store the index to layer1 function pointers */
+/* layer1_fin index to fptr_[] is in lowest 2 bits of fd */
+#define get_ttyfd() int layer1_fin = fd & 3; int ttyfd = fd / 4;\
+ if (fd < 0) {ttyfd = fd; layer1_fin = 0; /* use modbusTCP */}
+
+
+
+
+/******************************************/
+/******************************************/
+/** **/
+/** Global Variables... **/
+/** **/
+/******************************************/
+/******************************************/
+/* The layer 1 (RTU, ASCII, TCP) implementations will be adding some
+ * header and tail bytes (e.g. CRC) to the packet we build here. Since
+ * layer1 will re-use the same buffer allocated in this slave layer
+ * (so as not to continuosly copy the same info from buffer to buffer),
+ * we need to allocate more bytes than those strictly required for this
+ * slave layer. Therefore, the extra_bytes parameter.
+ *
+ * Note that we add one more extra byte to the response buffer.
+ * This is because some response packets will not be starting off
+ * at byte 0, but rather at byte 1 of the buffer. This is in order
+ * to guarantee that the data that is sent on the buffer is aligned
+ * on even bytes (the 16 bit words!). This will allow the application
+ * (layer above the one implemented in this file - i.e. the callback
+ * functions) to reference this memory as an u16 *, without producing
+ * 'bus error' messages in some embedded devices that do not allow
+ * acessing u16 on odd numbered addresses.
+ */
+static int buff_extra_bytes_;
+#define RESP_BUFFER_SIZE (MAX_L2_FRAME_LENGTH + buff_extra_bytes_ + 1)
+
+/******************************************/
+/******************************************/
+/** **/
+/** Local Utility functions... **/
+/** **/
+/******************************************/
+/******************************************/
+
+
+/*
+ * Function to determine next transaction id.
+ *
+ * We use a library wide transaction id, which means that we
+ * use a new transaction id no matter what slave to which we will
+ * be sending the request...
+ */
+static inline u16 next_transaction_id(void) {
+ static u16 next_id = 0;
+ return next_id++;
+}
+
+
+/*
+ * Functions to convert u16 variables
+ * between network and host byte order
+ *
+ * NOTE: Modbus uses MSByte first, just like
+ * tcp/ip, so we could be tempted to use the htons() and
+ * ntohs() functions to guarantee code portability.
+ *
+ * However, on some embedded systems running Linux
+ * these functions only work if the 16 bit words are
+ * stored on even addresses. This is not always the
+ * case in our code, so we have to define our own
+ * conversion functions...
+ */
+
+/* if using gcc, use it to determine byte order... */
+#ifndef __BYTE_ORDER
+#if defined(__GNUC__)
+ /* We have GCC, which should define __LITTLE_ENDIAN__ */
+# if defined(__LITTLE_ENDIAN__)
+# define __BYTE_ORDER __LITTLE_ENDIAN
+# else
+# define __BYTE_ORDER __BIG_ENDIAN
+# endif
+#endif /* __GNUC__ */
+#endif /* __BYTE_ORDER */
+
+
+/* If we still don't know byte order, try to get it from */
+#ifndef __BYTE_ORDER
+#include
+#endif
+
+
+#ifndef __BYTE_ORDER
+# ifdef BYTE_ORDER
+# if BYTE_ORDER == LITTLE_ENDIAN
+# define __BYTE_ORDER __LITTLE_ENDIAN
+# else
+# if BYTE_ORDER == BIG_ENDIAN
+# define __BYTE_ORDER __BIG_ENDIAN
+# endif
+# endif
+# endif /* BYTE_ORDER */
+#endif /* __BYTE_ORDER */
+
+
+
+
+
+#ifdef __BYTE_ORDER
+# if __BYTE_ORDER == __LITTLE_ENDIAN
+
+/**************************************************************/
+/* u16 conversion functions to use on little endian platforms */
+/**************************************************************/
+
+static inline u16 mb_hton(u16 w) {
+ register u16 tmp;
+ tmp = (w & 0x00FF);
+ tmp = ((w & 0xFF00) >> 0x08) | (tmp << 0x08);
+ return(tmp);
+}
+#define mb_ntoh(a) mb_hton(a)
+
+static inline void mb_hton_count(u16 *w, int count) {
+ int i;
+ for (i = 0; i < count; i++) {
+ /* swap the bytes around...
+ * a = a ^ b;
+ * b = a ^ b;
+ * a = a ^ b;
+ */
+ ((u8 *)(w+i))[0] ^= ((u8 *)(w+i))[1];
+ ((u8 *)(w+i))[1] ^= ((u8 *)(w+i))[0];
+ ((u8 *)(w+i))[0] ^= ((u8 *)(w+i))[1];
+ }
+}
+#define mb_ntoh_count(w, count) mb_hton_count(w, count)
+
+
+
+# else
+# if __BYTE_ORDER == __BIG_ENDIAN
+/***********************************************************/
+/* u16 conversion functions to use on big endian platforms */
+/***********************************************************/
+
+ /* We do not need to swap the bytes around! */
+#define mb_ntoh(val) (val)
+#define mb_hton(val) (val)
+#define mb_hton_count(w, count) /* empty ! */
+#define mb_ntoh_count(w, count) /* empty ! */
+
+
+# else
+
+/********************************************************/
+/* u16 conversion functions to use on generic platforms */
+/********************************************************/
+
+ /* We don't know the byte order, so we revert to the
+ * standard htons() and ntohs() ...
+ */
+static inline u16 mb_hton(u16 h_value)
+ {return htons(h_value); /* return h_value; */}
+
+static inline u16 mb_ntoh(u16 m_value)
+ {return ntohs(m_value); /* return m_value; */}
+
+static inline void mb_hton_count(u16 *w, int count)
+ {int i; for (i = 0; i < count; i++) {w[i] = mb_hton(w[i]);}}
+
+static inline void mb_ntoh_count(u16 *w, int count)
+ {int i; for (i = 0; i < count; i++) {w[i] = mb_ntoh(w[i]);}}
+
+# endif
+# endif
+#endif /* __BYTE_ORDER */
+
+
+
+
+/* Safe versions of the conversion functions!
+ *
+ * Note that these functions always work, whatever the endiannes
+ * of the machine that executes it!
+ *
+ * It is also safe because the resulting value may be stored
+ * on an odd address even on machines that do not allow directly
+ * accessing u16 bit words on odd addresses.
+ */
+static inline int mb_hton_safe(u16 from, u16 *to_ptr) {
+ ((u8 *)to_ptr)[1] = (from & 0x00FF);
+ ((u8 *)to_ptr)[0] = ((from & 0xFF00) >> 0x08);
+ return 0;
+}
+
+#define mb_ntoh_safe(a, b) mb_hton_safe(a, b)
+
+
+/* return Most Significant Byte of value; */
+static inline u8 msb(u16 value)
+ {return (value >> 8) & 0xFF;}
+
+/* return Least Significant Byte of value; */
+static inline u8 lsb(u16 value)
+ {return value & 0xFF;}
+
+#define u16_v(char_ptr) (*((u16 *)(&(char_ptr))))
+
+
+
+
+
+
+
+
+
+/***********************************************/
+/***********************************************/
+/** **/
+/** Handle requests from master/client **/
+/** **/
+/***********************************************/
+/***********************************************/
+
+
+/* Handle functions 0x01 and 0x02 */
+typedef int (*read_bits_callback_t)(void *arg, u16 start_addr, u16 bit_count, u8 *data_bytes);
+static int handle_read_bits (u8 *query_packet,
+ u8 **resp_packet_ptr,
+ u8 *error_code,
+ read_bits_callback_t read_bits_callback,
+ void *callback_arg
+ ) {
+ u16 start_addr, count;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (read_bits_callback == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ /* in oprder for the data in this packet to be aligned on even numbered addresses, this
+ * response packet will start off at an odd numbered byte...
+ * We therefore add 1 to the address where the packet starts.
+ */
+ (*resp_packet_ptr)++;
+ resp_packet = *resp_packet_ptr;
+
+ /* NOTE:
+ * Modbus uses high level addressing starting off from 1, but
+ * this is sent as 0 on the wire!
+ * We could expect the user to specify high level addressing
+ * starting at 1, and do the conversion to start off at 0 here.
+ * However, to do this we would then need to use an u32 data type
+ * to correctly hold the address supplied by the user (which could
+ * correctly be 65536, which does not fit in an u16), which would
+ * in turn require us to check whether the address supplied by the user
+ * is correct (i.e. <= 65536).
+ * I decided to go with the other option of using an u16, and
+ * requiring the user to use addressing starting off at 0!
+ */
+ /* start_addr = mb_ntoh(u16_v(query_packet[2])) + 1; */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+ mb_ntoh_safe(u16_v(query_packet[4]), &count);
+
+ #ifdef DEBUG
+ printf("handle_read_input_bits() called. slave=%d, function=%d, start_addr=%d, count=%d\n",
+ query_packet[0], query_packet[1], start_addr, count);
+ #endif
+
+ if ((count > MAX_READ_BITS) || (count < 1))
+ {*error_code = ERR_ILLEGAL_DATA_VALUE; return -1;}
+
+ /* Remember, we are using addressing starting off at 0, in the start_addr variable! */
+ /* This means that he highest acceptable address is 65535, when count=1 .... */
+ /* Note the use of 65536 in the comparison will force automatic upgrade of u16 variables! */
+ /* => start_addr + count will nver overflow the u16 type! */
+ if (start_addr + count > 65536)
+ {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function (either 0x01 or 0x02 ! */
+ resp_packet[2] = (count + 7) / 8; /* number of data bytes = ceil(count/8) */
+
+ res = read_bits_callback(callback_arg, start_addr, count, &(resp_packet[3]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ return resp_packet[2] + 3; /* packet size is data length + 3 bytes -> slave, function, count */
+}
+
+
+
+/* Handle function 0x01 */
+int handle_read_output_bits (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks)
+ {return handle_read_bits(query_packet, resp_packet_ptr, error_code, callbacks->read_outbits, callbacks->arg);}
+
+/* Handle function 0x02 */
+int handle_read_input_bits (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks)
+ {return handle_read_bits(query_packet, resp_packet_ptr, error_code, callbacks->read_inbits, callbacks->arg);}
+
+
+
+
+/* Handle functions 0x03 and 0x04 */
+typedef int (*read_words_callback_t)(void *arg, u16 start_addr, u16 word_count, u16 *data_words);
+static int handle_read_words (u8 *query_packet,
+ u8 **resp_packet_ptr,
+ u8 *error_code,
+ read_words_callback_t read_words_callback,
+ void *callback_arg
+ ) {
+ u16 start_addr, count;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (read_words_callback == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ /* See equivalent comment in handle_read_bits() */
+ (*resp_packet_ptr)++;
+ resp_packet = *resp_packet_ptr;
+
+ /* See equivalent comment in handle_read_bits() */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+ mb_ntoh_safe(u16_v(query_packet[4]), &count);
+
+ #ifdef DEBUG
+ printf("handle_read_output_words() called. slave=%d, function=%d, start_addr=%d, count=%d\n",
+ query_packet[0], query_packet[1], start_addr, count);
+ #endif
+
+ if ((count > MAX_READ_REGS) || (count < 1))
+ {*error_code = ERR_ILLEGAL_DATA_VALUE; return -1;}
+
+ /* See equivalent comment in handle_read_bits() */
+ if (start_addr + count > 65536)
+ {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function code, either 0x03 or 0x04 !!!*/
+ resp_packet[2] = count * 2; /* number of bytes of data... */
+
+ res = read_words_callback(callback_arg, start_addr, count, (u16 *)&(resp_packet[3]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ /* convert all data from host to network byte order. */
+ mb_hton_count((u16 *)&(resp_packet[3]), count);
+
+ return resp_packet[2] + 3; /* packet size is data length + 3 bytes -> slave, function, count */
+}
+
+
+
+
+/* Handle function 0x03 */
+int handle_read_output_words (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks)
+ {return handle_read_words(query_packet, resp_packet_ptr, error_code, callbacks->read_outwords, callbacks->arg);}
+
+/* Handle function 0x04 */
+int handle_read_input_words (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks)
+ {return handle_read_words(query_packet, resp_packet_ptr, error_code, callbacks->read_inwords, callbacks->arg);}
+
+
+
+/* Handle function 0x05 */
+int handle_write_output_bit (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks) {
+ u16 start_addr;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (callbacks->write_outbits == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ resp_packet = *resp_packet_ptr;
+
+ /* See equivalent comment in handle_read_bits() */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+
+ #ifdef DEBUG
+ printf("handle_write_output_bit() called. slave=%d, function=%d, start_addr=%d\n",
+ query_packet[0], query_packet[1], start_addr);
+ #endif
+
+ // byte 5 Must be 0x00, byte 4 must be 0x00 or 0xFF !!
+ if ( (query_packet[5] != 0) ||
+ ((query_packet[4] != 0) && (query_packet[4] != 0xFF)))
+ {*error_code = ERR_ILLEGAL_DATA_VALUE; return -1;}
+
+ /* Address will always be valid, no need to check! */
+ // if (start_addr > 65535) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function */
+ resp_packet[2] = query_packet[2]; /* start address - hi byte */
+ resp_packet[3] = query_packet[3]; /* start address - lo byte */
+ resp_packet[4] = query_packet[4]; /* value: 0x00 or 0xFF */
+ resp_packet[5] = query_packet[5]; /* value: must be 0x00 */
+
+ res = (callbacks->write_outbits)(callbacks->arg, start_addr, 1, &(query_packet[4]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ return 6; /* response packet size, including slave id in byte 0 */
+}
+
+
+
+/* Handle function 0x06 */
+int handle_write_output_word (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks) {
+ u16 start_addr;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (callbacks->write_outwords == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ resp_packet = *resp_packet_ptr;
+
+ /* See equivalent comment in handle_read_bits() */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+
+ #ifdef DEBUG
+ printf("handle_write_output_word() called. slave=%d, function=%d, start_addr=%d\n",
+ query_packet[0], query_packet[1], start_addr);
+ #endif
+
+ /* Address will always be valid, no need to check! */
+ // if (start_addr > 65535) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function */
+ resp_packet[2] = query_packet[2]; /* start address - hi byte */
+ resp_packet[3] = query_packet[3]; /* start address - lo byte */
+ resp_packet[4] = query_packet[4]; /* value - hi byte */
+ resp_packet[5] = query_packet[5]; /* value - lo byte */
+
+ /* convert data from network to host byte order */
+ mb_ntoh_count((u16 *)&(query_packet[4]), 1);
+
+ res = (callbacks->write_outwords)(callbacks->arg, start_addr, 1, (u16 *)&(query_packet[4]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ return 6; /* packet size is 6 -> slave, function, addr(2), value(2) */
+}
+
+
+
+/* Handle function 0x0F */
+int handle_write_output_bits (u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks) {
+ u16 start_addr, count;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (callbacks->write_outbits == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ resp_packet = *resp_packet_ptr;
+
+ /* See equivalent comment in handle_read_bits() */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+ mb_ntoh_safe(u16_v(query_packet[4]), &count);
+
+ #ifdef DEBUG
+ printf("handle_write_output_bits() called. slave=%d, function=%d, start_addr=%d, count=%d\n",
+ query_packet[0], query_packet[1], start_addr, count);
+ #endif
+
+ if ((count > MAX_WRITE_COILS) || (count < 1) || ((count+7)/8 != query_packet[6]) )
+ {*error_code = ERR_ILLEGAL_DATA_VALUE; return -1;}
+
+ /* See equivalent comment in handle_read_bits() */
+ if (start_addr + count > 65536)
+ {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function */
+ resp_packet[2] = query_packet[2]; /* start address - hi byte */
+ resp_packet[3] = query_packet[3]; /* start address - lo byte */
+ resp_packet[4] = query_packet[4]; /* count - hi byte */
+ resp_packet[5] = query_packet[5]; /* count - lo byte */
+
+ res = (callbacks->write_outbits)(callbacks->arg, start_addr, count, &(query_packet[7]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ return 6; /* packet size is 6 -> slave, function, addr(2), count(2) */
+}
+
+
+
+
+/* Handle function 0x10 */
+int handle_write_output_words(u8 *query_packet, u8 **resp_packet_ptr, u8 *error_code, mb_slave_callback_t *callbacks) {
+ u16 start_addr, count;
+ int res;
+ u8 *resp_packet;
+
+ /* If no callback, handle as if function is not supported... */
+ if (callbacks->write_outwords == NULL)
+ {*error_code = ERR_ILLEGAL_FUNCTION; return -1;}
+
+ resp_packet = *resp_packet_ptr;
+
+ /* See equivalent comment in handle_read_bits() */
+ mb_ntoh_safe(u16_v(query_packet[2]), &start_addr);
+ mb_ntoh_safe(u16_v(query_packet[4]), &count);
+
+ if ((count > MAX_WRITE_REGS) || (count < 1) || (count*2 != query_packet[6]) )
+ {*error_code = ERR_ILLEGAL_DATA_VALUE; return -1;}
+
+ /* See equivalent comment in handle_read_bits() */
+ if (start_addr + count > 65536)
+ {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+
+ /* start building response frame... */
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1]; /* function */
+ resp_packet[2] = query_packet[2]; /* start address - hi byte */
+ resp_packet[3] = query_packet[3]; /* start address - lo byte */
+ resp_packet[4] = query_packet[4]; /* count - hi byte */
+ resp_packet[5] = query_packet[5]; /* count - lo byte */
+
+ /* convert all data from network to host byte order */
+ mb_ntoh_count((u16 *)&(query_packet[7]), count);
+
+ res = (callbacks->write_outwords)(callbacks->arg, start_addr, count, (u16 *)&(query_packet[7]));
+ if (res == -2) {*error_code = ERR_ILLEGAL_DATA_ADDRESS; return -1;}
+ if (res < 0) {*error_code = ERR_SLAVE_DEVICE_FAILURE; return -1;}
+
+ return 6; /* packet size is 6 -> slave, function, addr(2), count(2) */
+}
+
+
+
+
+
+
+
+
+/***********************************************/
+/***********************************************/
+/** **/
+/** initialise / shutdown the library **/
+/** **/
+/***********************************************/
+/***********************************************/
+
+int mb_slave_init__(int extra_bytes) {
+ buff_extra_bytes_ = extra_bytes;
+ return 0;
+}
+
+
+int mb_slave_done__(void)
+ {return 0;}
+
+
+#if 0
+int mb_slave_init(int nd_count) {
+ int extra_bytes;
+
+ #ifdef DEBUG
+ fprintf( stderr, "mb_slave_init()\n");
+ fprintf( stderr, "creating %d nodes\n", nd_count);
+ #endif
+
+ /* initialise layer 1 library */
+ if (modbus_init(nd_count, DEF_OPTIMIZATION, &extra_bytes) < 0)
+ goto error_exit_0;
+
+ /* initialise this library */
+ if (mb_slave_init__(extra_bytes) < 0)
+ goto error_exit_1;
+
+ return 0;
+
+error_exit_1:
+ modbus_done();
+error_exit_0:
+ return -1;
+}
+
+
+int mb_slave_done(void) {
+ mb_slave_done__(void)
+ return modbus_done();
+}
+#endif
+
+
+
+/***********************************************/
+/***********************************************/
+/** **/
+/** open/close slave connection **/
+/** **/
+/***********************************************/
+/***********************************************/
+
+/* Create a new slave/server */
+/* NOTE: We use the lower 2 bits of the returned node id to identify which
+ * layer1 implementation to use.
+ * 0 -> TCP
+ * 1 -> RTU
+ * 2 -> ASCII
+ * 4 -> unused
+ * The node id used by the layer1 is shifted left 2 bits
+ * before returning the node id to the caller!
+ */
+int mb_slave_new(node_addr_t node_addr) {
+ int res = -1;
+ #ifdef DEBUG
+ fprintf( stderr, "mb_slave_connect()\n");
+ #endif
+
+ /* call layer 1 library */
+ switch(node_addr.naf) {
+ case naf_tcp:
+ res = modbus_tcp_listen(node_addr);
+ if (res >= 0) res = res*4 + 0 /* offset into fptr_ with TCP functions */;
+ return res;
+ case naf_rtu:
+ res = modbus_rtu_listen(node_addr);
+ if (res >= 0) res = res*4 + 1 /* offset into fptr_ with RTU functions */;
+ return res;
+ case naf_ascii:
+ res = modbus_ascii_listen(node_addr);
+ if (res >= 0) res = res*4 + 2 /* offset into fptr_ with ASCII functions */;
+ return res;
+ }
+
+ return -1;
+}
+
+
+
+
+int mb_slave_close(int fd) {
+ #ifdef DEBUG
+ fprintf( stderr, "mb_slave_close(): nd = %d\n", fd);
+ #endif
+ get_ttyfd(); /* declare the ttyfd variable!! */
+ /* call layer 1 library */
+ /* will call one of modbus_tcp_close(), modbus_rtu_close(), modbus_ascii_close() */
+ return modbus_close(ttyfd);
+}
+
+
+
+
+
+/***********************************************/
+/***********************************************/
+/** **/
+/** Run the slave **/
+/** **/
+/***********************************************/
+/***********************************************/
+
+/* Execute infinite loop waiting and replying to requests coming from clients/master
+ * This function enters an infinite loop wating for new connection requests,
+ * and for modbus requests over previoulsy open connections...
+ *
+ * The frames are read from:
+ * - the node descriptor nd, if nd >= 0
+ * When using TCP, if the referenced node nd was created to listen for new connections
+ * [mb_slave_listen()], then this function will also reply to Modbus data requests arriving
+ * on other nodes that were created as a consequence of accepting connections requests to
+ * the referenced node nd.
+ * All other nodes are ignored!
+ *
+ * - any valid and initialised TCP node descriptor, if nd = -1
+ * In this case, will also accept connection requests arriving from a previously
+ * created node to listen for new connection requests [mb_slave_listen() ].
+ * NOTE: (only avaliable if using TCP)
+ *
+ * slaveid identifies the address (RTU and ASCII) or slaveid (TCP) that we implement.
+ * Any requests that we receive sent with a slaveid different
+ * than the one specified, and also different to 0, will be silently ignored!
+ * Whatever the slaveid specified, we always reply to requests
+ * to slaveid 0 (the modbus broadcast address).
+ * Calling this function with a slaveid of 0 means to ignore this
+ * parameter and to reply to all requests (whatever the slaveid
+ * used in the request). This should mostly be used by TCP servers...
+ */
+
+int mb_slave_run(int fd, mb_slave_callback_t callback_functions, u8 slaveid) {
+ int byte_count;
+ u16 transaction_id;
+ int nd;
+ u8 function, error_code = 0;
+ int resp_length;
+ u8 *query_packet = NULL;
+ u8 *resp_packet;
+ u8 resp_buffer_[RESP_BUFFER_SIZE];
+ u8 slave;
+
+ get_ttyfd(); /* declare the ttyfd variable!! */
+
+ #ifdef DEBUG
+ fprintf(stderr,"[%lu] mb_slave_run(): Called... fd=%d, ttyfd=%d\n", pthread_self(), fd, ttyfd);
+ #endif
+
+ while(1) {
+ nd = ttyfd;
+ /* will call one of modbus_tcp_read(), modbus_rtu_read(), modbus_ascii_read() */
+ do {
+ byte_count = modbus_read(&nd, /* node descriptor */
+ &query_packet, /* u8 **recv_data_ptr, */
+ &transaction_id, /* u16 *transaction_id, */
+ NULL, /* const u8 *send_data, */
+ 0, /* int send_length, */
+ NULL /* wait indefenitely */ /* const struct timespec *recv_timeout); */
+ );
+ } while (byte_count <= 2);
+
+ #ifdef DEBUG
+ {/* display the hex code of each character received */
+ int i;
+ printf("[%lu] mb_slave_run() received %d bytes (ptr=%p): \n", pthread_self(), byte_count, query_packet);
+ for (i=0; i < byte_count; i++)
+ printf("<0x%2X>", query_packet[i]);
+ printf("\n");
+ }
+ #endif
+
+ slave = query_packet[0];
+ function = query_packet[1];
+
+ /* We only reply if:
+ * - request was sent to broadcast address (slave == 0)
+ * OR - we were asked to reply to every request (slaveid == 0)
+ * OR - request matches the slaveid we were asked to accept (slave == slaveid)
+ *
+ * Otherwise, silently ignore the received request!!!
+ */
+ if ((slaveid == 0) || (slave == 0) || (slave == slaveid)) {
+ resp_packet = resp_buffer_;
+
+ switch(function) {
+ case 0x01: resp_length = handle_read_output_bits (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x02: resp_length = handle_read_input_bits (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x03: resp_length = handle_read_output_words (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x04: resp_length = handle_read_input_words (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x05: resp_length = handle_write_output_bit (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x06: resp_length = handle_write_output_word (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x0F: resp_length = handle_write_output_bits (query_packet, &resp_packet, &error_code, &callback_functions); break;
+ case 0x10: resp_length = handle_write_output_words(query_packet, &resp_packet, &error_code, &callback_functions); break;
+ /* return exception code 0x01 -> function not supported! */
+ default : resp_length = -1; error_code = 0x01; break;
+ }; /* switch(function) */
+
+ if (resp_length < 0) {
+ /* return error... */
+ /* build exception response frame... */
+ resp_packet = resp_buffer_;
+ resp_packet[0] = query_packet[0]; /* slave */
+ resp_packet[1] = query_packet[1] | 0x80; /* function code with error bit activated! */
+ resp_packet[2] = error_code;
+ resp_length = 3;
+ }
+ modbus_write(nd, resp_packet, resp_length, transaction_id, NULL /*transmit_timeout*/);
+ }; /* if not ignore request */
+ }; /* while(1) */
+
+ /* humour the compiler... */
+ return 0;
+}
+
+
+
+
+
+
+
+
+
+
+
+
+