Add command-line and config options to set an TCP socket address (#53)

Still no IPv6 support though.

README.md

@@ -53,8 +53,8 @@ Usage:
 ------
 
        mbusd [-h] [-d] [-L logfile] [-v level] [-c cfgfile] [-p device] [-s speed] [-m mode]
-       		[-t] [-y file] [-Y file] [-P port] [-C maxconn] [-N retries]
-       		[-R pause] [-W wait] [-T timeout]
+             [-t] [-y file] [-Y file] [-A address] [-P port] [-C maxconn] [-N retries]
+             [-R pause] [-W wait] [-T timeout]
 
        -h     Usage help.
        -d     Instruct mbusd not to fork itself (non-daemonize).
@@ -80,6 +80,8 @@ Usage:
        -Y file
               Enable RS-485 direction data direction control by writing '0' to file
               for transmitter enable and '1' to file for transmitter disable
+       -A address
+             Specifies TCP address to bind (default 0.0.0.0).
        -P port
               Specifies TCP port number (default 502).
        -C maxconn

conf/mbusd.conf.example

@@ -23,6 +23,9 @@ trx_control = addc
 
 ############# TCP port settings #############
 
+# TCP server address to bind
+address = 0.0.0.0
+
 # TCP server port number
 port = 502
 

doc/mbusd.8.in

@@ -22,6 +22,8 @@ mbusd \- MODBUS/TCP to MODBUS/RTU gateway.
 .IR file ]
 .RB [ -Y
 .IR file ]
+.RB [ -A
+.IR address ]
 .RB [ -P
 .IR port ]
 .RB [ -C
@@ -57,6 +59,8 @@ Specifies serial port device name.
 Specifies serial port speed.
 .IP "\fB-m \fImode\fR"
 Specifies serial port mode (like 8N1).
+.IP "\fB-A \fIaddress\fR"
+Specifies TCP address to bind.
 .IP "\fB-P \fIport\fR"
 Specifies TCP port number.
 .IP \fB-t\fR

src/cfg.c

@@ -67,6 +67,7 @@ cfg_init(void)
   cfg.trxcntl = TRX_ADDC;
   *cfg.trxcntl_file = '\0';
 #endif
+  strncpy(cfg.serveraddr, DEFAULT_SERVERADDR, INTBUFSIZE);
   cfg.serverport = DEFAULT_SERVERPORT;
   cfg.maxconn = DEFAULT_MAXCONN;
   cfg.maxtry = DEFAULT_MAXTRY;
@@ -122,6 +123,10 @@ cfg_handle_param(char *name, char *value)
     }
     strncpy(cfg.ttymode, value, INTBUFSIZE);
   }
+  else if (CFG_NAME_MATCH("address"))
+  {
+    strncpy(cfg.serveraddr, value, INTBUFSIZE);
+  }
   else if (CFG_NAME_MATCH("port"))
   {
     cfg.serverport = strtoul(value, NULL, 0);

src/cfg.h

@@ -58,6 +58,8 @@ typedef struct
   int trxcntl;
   /* trx control sysfs file */
   char trxcntl_file[INTBUFSIZE + 1];
+  /* TCP server address */
+  char serveraddr[INTBUFSIZE + 1];
   /* TCP server port number */
   int serverport;
   /* maximum number of connections */

src/conn.c

@@ -113,13 +113,12 @@ conn_init(void)
   state_tty_set(&tty, TTY_PAUSE);
 
   /* create server socket */
-  if ((server_sd =
-         sock_create_server("", cfg.serverport, TRUE)) < 0)
+  if ((server_sd = sock_create_server(cfg.serveraddr, cfg.serverport, TRUE)) < 0)
   {
 #ifdef LOG
     logw(0, "conn_init():"
-           " can't create listen() socket (%s)",
-           strerror(errno));
+           " can't create listen socket (%s)",
+           (errno != 0) ? strerror(errno) : "failed");
 #endif
     return RC_ERR;
   }

src/conn.h

@@ -46,6 +46,7 @@
 /*
  * Default values
  */
+#define DEFAULT_SERVERADDR "0.0.0.0"
 #define DEFAULT_SERVERPORT 502
 #define DEFAULT_MAXCONN 32
 #define DEFAULT_MAXTRY 3

src/main.c

@@ -111,7 +111,8 @@ usage(char *exename)
 #ifdef TRXCTL
    "             [-t] [-y sysfsfile] [-Y sysfsfile]\n"
 #endif
-   "             [-P port] [-C maxconn] [-N retries] [-R pause] [-W wait] [-T timeout]\n\n"
+   "             [-A address] [-P port] [-C maxconn] [-N retries]\n"
+   "             [-R pause] [-W wait] [-T timeout]\n\n"
    "Options:\n"
    "  -h         : this help\n"
    "  -d         : don't daemonize\n"
@@ -128,6 +129,7 @@ usage(char *exename)
    "  -p device  : set serial port device name (default %s)\n"
    "  -s speed   : set serial port speed (default %d)\n"
    "  -m mode    : set serial port mode (default %s)\n"
+   "  -A address : set TCP server address to bind (default %s)\n"
    "  -P port    : set TCP server port number (default %d)\n"
 #ifdef TRXCTL
    "  -t         : enable RTS RS-485 data direction control using RTS\n"
@@ -148,7 +150,8 @@ usage(char *exename)
 #ifdef LOG
       LOGPATH, LOGNAME, cfg.dbglvl,
 #endif
-      cfg.ttyport, cfg.ttyspeed, cfg.ttymode, cfg.serverport,
+      cfg.ttyport, cfg.ttyspeed, cfg.ttymode,
+      cfg.serveraddr, cfg.serverport,
       MAX_MAXCONN, cfg.maxconn, MAX_MAXTRY, cfg.maxtry,
       MAX_RQSTPAUSE, cfg.rqstpause, MAX_RESPWAIT, cfg.respwait,
       MAX_CONNTIMEOUT, cfg.conntimeout);
@@ -180,7 +183,7 @@ main(int argc, char *argv[])
 #ifdef LOG
                "v:L:"
 #endif
-               "p:s:m:P:C:N:R:W:T:c:")) != RC_ERR)
+               "p:s:m:A:P:C:N:R:W:T:c:")) != RC_ERR)
   {
     switch (rc)
     {
@@ -290,6 +293,9 @@ main(int argc, char *argv[])
           exit(-1);
         }
         break;
+      case 'A':
+        strncpy(cfg.serveraddr, optarg, INTBUFSIZE);
+        break;
       case 'P':
         cfg.serverport = strtoul(optarg, NULL, 0);
         break;

src/sock.c

@@ -94,13 +94,33 @@ sock_create(int blkmode)
  * Return: socket descriptor, otherwise RC_ERR if there some errors
  */
 int
-sock_create_server(char *server_ip,
-  unsigned short server_port, int blkmode)
+sock_create_server(char *server_ip, unsigned short server_port, int blkmode)
 {
   struct sockaddr_in server_sockaddr;
   int sock_opt = 1;
   int server_s;
 
+  memset(&server_sockaddr, 0, sizeof(server_sockaddr));
+  server_sockaddr.sin_family = AF_INET; // FIXME IPv6 support
+
+  /* parse address to bind socket */
+  if (server_ip != NULL)
+  {
+    if (inet_aton(server_ip, &server_sockaddr.sin_addr) == 0)
+    {
+#ifdef LOG
+      logw(0, "sock_create_server():"
+           " can't parse address: %s",
+           server_ip);
+#endif
+      return RC_ERR;
+    }
+  }
+  else
+    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+
+  server_sockaddr.sin_port = htons(server_port);
+
   /* create socket in desired blocking mode */
   server_s = sock_create(blkmode);
   if (server_s < 0) return server_s;
@@ -144,18 +164,9 @@ sock_create_server(char *server_ip,
     return RC_ERR;
   }
 
-  memset(&server_sockaddr, 0, sizeof(server_sockaddr));
-  server_sockaddr.sin_family = AF_INET;
-
-  if (server_ip != NULL)
-    inet_aton(server_ip, &server_sockaddr.sin_addr);
-  else
-    server_sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
-
-  server_sockaddr.sin_port = htons(server_port);
-
+  /* bind socket to given address and port */
   if (bind(server_s, (struct sockaddr *) & server_sockaddr,
-	   sizeof(server_sockaddr)) == -1)
+           sizeof(server_sockaddr)) == -1)
   {
 #ifdef LOG
     logw(0, "sock_create_server():"
@@ -207,7 +218,7 @@ sock_accept(int server_sd, struct sockaddr_in *rmt_addr, int blkmode)
   if (sock_set_blkmode(sd, blkmode) == RC_ERR)
   {
 #ifdef LOG
-    logw(0, "sock_accept(): can't set socket blocking mode (%s)", 
+    logw(0, "sock_accept(): can't set socket blocking mode (%s)",
            strerror(errno));
 #endif
     close(sd);