From b22ffa08569ac8e00b6402bc2652562261ae8ea1 Mon Sep 17 00:00:00 2001
From: Danny <danny.goossen@gioxa.com>
Date: Sat, 19 Jun 2021 12:37:55 +0700
Subject: [PATCH] feature-reply-on-broadcast

---
 README.md               |  2 ++
 conf/mbusd.conf.example |  3 +++
 doc/mbusd.8.in          |  3 +++
 src/cfg.c               |  5 +++++
 src/cfg.h               |  2 ++
 src/conn.c              | 16 +++++++++++++---
 src/main.c              | 12 ++++++++----
 7 files changed, 36 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index 3e1def3..21ed479 100644
--- a/README.md
+++ b/README.md
@@ -94,6 +94,8 @@ Usage:
               Specifies response wait time in milliseconds.
        -T timeout
               Specifies connection timeout value in seconds (0 disables timeout).
+       -b 
+              Reply on a Broadcast
 
 Please note running **mbusd** on default Modbus TCP port (502) requires root privileges!
 
diff --git a/conf/mbusd.conf.example b/conf/mbusd.conf.example
index dc2ada0..116d01c 100644
--- a/conf/mbusd.conf.example
+++ b/conf/mbusd.conf.example
@@ -45,3 +45,6 @@ pause = 100
 
 # Response wait time in milliseconds
 wait = 500
+
+# Reply on Broadcast
+#replyonbroadcast
diff --git a/doc/mbusd.8.in b/doc/mbusd.8.in
index 7988241..27b147b 100644
--- a/doc/mbusd.8.in
+++ b/doc/mbusd.8.in
@@ -36,6 +36,7 @@ mbusd \- MODBUS/TCP to MODBUS/RTU gateway.
 .IR wait ]
 .RB [ -T
 .IR timeout ]
+.RB [ -b ]
 .SH DESCRIPTION
 \fImbusd\fR is MODBUS/TCP to MODBUS/RTU gateway.
 .SH OPTIONS
@@ -81,6 +82,8 @@ Specifies pause between requests in milliseconds.
 Specifies response wait time in milliseconds.
 .IP "\fB-T \fItimeout\fR"
 Specifies connection timeout value in seconds (0 - disable timeout).
+.IP "\fB-b\fR"
+Instruct \fImbusd\fR to reply on a broadcast
 .SH NOTES
 In case of situation when \fImbusd\fR received response with invalid CRC and can't correct
 error by re-request, it return MODBUS/TCP packet with exception code 04. In case of situation
diff --git a/src/cfg.c b/src/cfg.c
index d0c5bc8..3e2c6ae 100644
--- a/src/cfg.c
+++ b/src/cfg.c
@@ -74,6 +74,7 @@ cfg_init(void)
   cfg.rqstpause = DEFAULT_RQSTPAUSE;
   cfg.respwait = DEFAULT_RESPWAIT;
   cfg.conntimeout = DEFAULT_CONNTIMEOUT;
+  cfg.replyonbroadcast=0;
 }
 
 static char *
@@ -171,6 +172,10 @@ cfg_handle_param(char *name, char *value)
       CFG_ERR("invalid wait value: %s", value);
       return 0;
     }
+  }
+   else if (CFG_NAME_MATCH("replyonbroadcast"))
+  {
+    cfg.replyonbroadcast = 1;
   }
   else if (CFG_NAME_MATCH("timeout"))
   {
diff --git a/src/cfg.h b/src/cfg.h
index 40d8af6..0f0033f 100644
--- a/src/cfg.h
+++ b/src/cfg.h
@@ -72,6 +72,8 @@ typedef struct
   unsigned long rqstpause;
   /* response waiting time (in msec) */
   unsigned long respwait;
+  /* reply to client on broadcast */
+  int replyonbroadcast;
 } cfg_t;
 
 /* Prototypes */
diff --git a/src/conn.c b/src/conn.c
index 1ff7e9a..a9f17a3 100644
--- a/src/conn.c
+++ b/src/conn.c
@@ -560,12 +560,22 @@ conn_loop(void)
 #endif
           if (!tty.txbuf[0])
           {
-            /* broadcast request sent, no reply expected */
-            state_conn_set(actconn, CONN_HEADER);
-            state_tty_set(&tty, TTY_PAUSE);
 #ifdef DEBUG
             logw(5, "conn[%s]: broadcast request sent", curconn->remote_addr);
 #endif
+            /* broadcast request sent, no reply expected from TTY*/
+            state_tty_set(&tty, TTY_PAUSE);
+            if (cfg.replyonbroadcast)
+            {
+                /* switch connection to response state, reply w actconn->buf */
+                state_conn_set(actconn, CONN_RESP);
+            }
+            else
+            {
+                /* Done, ready for next */
+                state_conn_set(actconn, CONN_HEADER);
+            }
+
           }
           else
           {
diff --git a/src/main.c b/src/main.c
index e4cdeea..77eba44 100644
--- a/src/main.c
+++ b/src/main.c
@@ -112,7 +112,7 @@ usage(char *exename)
    "             [-t] [-y sysfsfile] [-Y sysfsfile]\n"
 #endif
    "             [-A address] [-P port] [-C maxconn] [-N retries]\n"
-   "             [-R pause] [-W wait] [-T timeout]\n\n"
+   "             [-R pause] [-W wait] [-T timeout] [-b]\n\n"
    "Options:\n"
    "  -h         : this help\n"
    "  -d         : don't daemonize\n"
@@ -145,7 +145,8 @@ usage(char *exename)
    "  -W wait    : set response wait time in milliseconds\n"
    "               (1-%d, default %lu)\n"
    "  -T timeout : set connection timeout value in seconds\n"
-   "               (0-%d, default %d, 0 - no timeout)"
+   "               (0-%d, default %d, 0 - no timeout)\n"
+   "  -b         : reply on broadcast (default %d)"   
    "\n", PACKAGE, VERSION, exename,
 #ifdef LOG
       LOGPATH, LOGNAME, cfg.dbglvl,
@@ -154,7 +155,7 @@ usage(char *exename)
       cfg.serveraddr, cfg.serverport,
       MAX_MAXCONN, cfg.maxconn, MAX_MAXTRY, cfg.maxtry,
       MAX_RQSTPAUSE, cfg.rqstpause, MAX_RESPWAIT, cfg.respwait,
-      MAX_CONNTIMEOUT, cfg.conntimeout);
+      MAX_CONNTIMEOUT, cfg.conntimeout, cfg.replyonbroadcast);
   exit(0);
 }
 
@@ -184,7 +185,7 @@ main(int argc, char *argv[])
 #ifdef LOG
                "v:L:"
 #endif
-               "p:s:m:A:P:C:N:R:W:T:c:")) != RC_ERR)
+               "p:s:m:A:P:C:N:R:W:T:c:b")) != RC_ERR)
   {
     switch (rc)
     {
@@ -350,6 +351,9 @@ main(int argc, char *argv[])
           exit(-1);
         }
         break;
+      case 'b':
+        cfg.replyonbroadcast = 1;
+        break;
       case 'h':
         usage(exename);
         break;