Fixed the bug that was causing overbuffering of socket traffic and lending

to big delays between the master and the slave.

diff --git a/src/Network/fg_socket.cxx b/src/Network/fg_socket.cxx
index 64882c3f53829fb381acce331da5564e1c17f9c4..a4e300fe53917015a4cbbec016ad7cc66629bd71 100644 (file)
--- a/src/Network/fg_socket.cxx
+++ b/src/Network/fg_socket.cxx
@@ -27,8 +27,10 @@
 #include <sys/types.h>         // socket(), bind(), select(), accept()
 #include <sys/socket.h>                // socket(), bind(), listen(), accept()
 #include <netinet/in.h>                // struct sockaddr_in
+#include <netinet/tcp.h>       // #define TCP_NODELAY, this attempts to 
+                                // disable the Nagle algorithm.
 #include <netdb.h>             // gethostbyname()
-#include <unistd.h>            // select()
+#include <unistd.h>            // select(), fsync()/fdatasync()
 
 #include STL_STRING
 
@@ -218,30 +220,35 @@ int FGSocket::readline( char *buf, int length ) {
        char *buf_ptr = save_buf + save_len;
        result = std::read( sock, buf_ptr, FG_MAX_MSG_SIZE - save_len );
        save_len += result;
+       cout << "current read = " << buf_ptr << endl;
+       cout << "current save_buf = " << save_buf << endl;
+       cout << "save_len = " << save_len << endl;
+    }
 
-       // look for the end of line in save_buf
-       int i;
-       for ( i = 0; i < save_len && save_buf[i] != '\n'; ++i );
-       if ( save_buf[i] == '\n' ) {
-           result = i + 1;
-       } else {
-           // no end of line yet
-           return 0;
-       }
-
-       // we found an end of line
+    // look for the end of line in save_buf
+    int i;
+    for ( i = 0; i < save_len && save_buf[i] != '\n'; ++i );
+    if ( save_buf[i] == '\n' ) {
+       result = i + 1;
+    } else {
+       // no end of line yet
+       cout << "no eol found" << endl;
+       return 0;
+    }
+    cout << "line length = " << result << endl;
 
-       // copy to external buffer
-       strncpy( buf, save_buf, result );
-       buf[result] = '\0';
-       cout << "fg_serial line = " << buf << endl;
+    // we found an end of line
 
-       // shift save buffer
-       for ( i = result; i < save_len; ++i ) {
-           save_buf[ i - result ] = save_buf[i];
-       }
-       save_len -= result;
+    // copy to external buffer
+    strncpy( buf, save_buf, result );
+    buf[result] = '\0';
+    cout << "fg_socket line = " << buf << endl;
+    
+    // shift save buffer
+    for ( i = result; i < save_len; ++i ) {
+       save_buf[ i - result ] = save_buf[i];
     }
+    save_len -= result;
 
     return result;
 }
@@ -269,17 +276,44 @@ int FGSocket::write( char *buf, int length ) {
            FG_LOG( FG_IO, FG_ALERT, 
                    "Error: accept() failed in write()" );
            return 0;
+           int flag = 1;
+           int result = setsockopt(sock,         /* socket affected */
+                                   IPPROTO_TCP,  /* set option at TCP level */
+                                   TCP_NODELAY,  /* name of option */
+                                   (char *) &flag,/* the cast is historical
+                                                      cruft */
+                                   sizeof(int)); /* length of option value */
+           if (result < 0) {
+               FG_LOG( FG_IO, FG_ALERT, 
+                       "Error: setsockopt() failed in write()" );
+               return 0;
+       
+           }
        } else {
            client_connections.push_back( msgsock );
        }
     }
 
     bool error_condition = false;
+    FG_LOG( FG_IO, FG_INFO, "Client connections = " << 
+           client_connections.size() );
     for ( int i = 0; i < (int)client_connections.size(); ++i ) {
        int msgsock = client_connections[i];
+
+       // read and junk any possible incoming messages.
+       // char junk[ FG_MAX_MSG_SIZE ];
+       // std::read( msgsock, junk, FG_MAX_MSG_SIZE );
+
+       // write the interesting data to the socket
        if ( std::write(msgsock, buf, length) < 0 ) {
            FG_LOG( FG_IO, FG_ALERT, "Error writing to socket: " << port );
            error_condition = true;
+       } else {
+#ifdef _POSIX_SYNCHRONIZED_IO
+           // fdatasync(msgsock);
+#else
+           // fsync(msgsock);
+#endif
        }
     }