Prevention for occasional corrupted messages (#26)

Prevention for occasional corrupted messages caused mostly due to system high load.

3 files changed, 56 insertions, 21 deletions

diff --git a/src/daemon/dlt_daemon_connection.c b/src/daemon/dlt_daemon_connection.c
index 8d2aa67..58b8a72 100644
--- a/src/daemon/dlt_daemon_connection.c
+++ b/src/daemon/dlt_daemon_connection.c
@@ -46,6 +46,7 @@
 #include "dlt_daemon_common.h"
 #include "dlt_common.h"
 #include "dlt_gateway.h"
+#include "dlt_daemon_socket.h"
 
 static DltConnectionId connectionId;
 
@@ -76,12 +77,14 @@ STATIC int dlt_connection_send(DltConnection *conn,
 
     switch (type)
     {
-    case DLT_CONNECTION_CLIENT_MSG_SERIAL:
-        return write(conn->receiver->fd, msg, msg_size);
+    case DLT_CONNECTION_CLIENT_MSG_SERIAL:        
+        if(write(conn->receiver->fd, msg, msg_size) > 0)
+            return DLT_DAEMON_ERROR_OK;
+        return DLT_DAEMON_ERROR_UNKNOWN;
     case DLT_CONNECTION_CLIENT_MSG_TCP:
-        return send(conn->receiver->fd, msg, msg_size, 0);
+        return dlt_daemon_socket_sendreliable(conn->receiver->fd, msg, msg_size);
     default:
-        return -1;
+        return DLT_DAEMON_ERROR_UNKNOWN;
     }
 }
 
@@ -110,7 +113,7 @@ int dlt_connection_send_multiple(DltConnection *con,
 
     if (con == NULL)
     {
-        return -1;
+        return DLT_DAEMON_ERROR_UNKNOWN;
     }
 
     if (sendserialheader)
@@ -120,21 +123,16 @@ int dlt_connection_send_multiple(DltConnection *con,
                                  sizeof(dltSerialHeader));
     }
 
-    if ((data1 != NULL) && (ret >= 0))
+    if ((data1 != NULL) && (ret == DLT_RETURN_OK ))
     {
         ret = dlt_connection_send(con, data1, size1);
     }
 
-    if ((data2 != NULL) && (ret >= 0))
+    if ((data2 != NULL) && (ret == DLT_RETURN_OK))
     {
         ret = dlt_connection_send(con, data2, size2);
     }
 
-    if (ret >=0)
-    {
-        ret = DLT_DAEMON_ERROR_OK;
-    }
-
     return ret;
 }
 
diff --git a/src/daemon/dlt_daemon_socket.c b/src/daemon/dlt_daemon_socket.c
index 686f4d6..098537f 100644
--- a/src/daemon/dlt_daemon_socket.c
+++ b/src/daemon/dlt_daemon_socket.c
@@ -145,26 +145,54 @@ int dlt_daemon_socket_close(int sock)
 int dlt_daemon_socket_send(int sock,void* data1,int size1,void* data2,int size2,char serialheader)
 {
     /* Optional: Send serial header, if requested */
+    int ret = DLT_RETURN_OK;
     if (serialheader)
     {
-        if ( 0 > send(sock, dltSerialHeader,sizeof(dltSerialHeader),0) )
-            return DLT_DAEMON_ERROR_SEND_FAILED;
-
+         ret = dlt_daemon_socket_sendreliable(sock, (void *) dltSerialHeader, sizeof(dltSerialHeader));
+         if(ret != DLT_RETURN_OK)
+             return ret;
     }
 
     /* Send data */
-    if(data1 && size1>0)
+    if(data1 != NULL && size1 > 0)
     {
-        if (0 > send(sock, data1,size1,0))
-            return DLT_DAEMON_ERROR_SEND_FAILED;
+        ret = dlt_daemon_socket_sendreliable(sock, data1, size1);
+        if(ret != DLT_RETURN_OK)
+            return ret;
     }
 
-    if(data2 && size2>0)
+    if(data2 != NULL && size2 > 0)
     {
-        if (0 > send(sock, data2,size2,0))
-        return DLT_DAEMON_ERROR_SEND_FAILED;
+        ret = dlt_daemon_socket_sendreliable(sock, data2, size2);
+        if(ret != DLT_RETURN_OK)
+            return ret;
     }
 
+    return ret;
+}
+
+int dlt_daemon_socket_sendreliable(int sock, void* buffer,int  message_size)
+{
+    int data_sent = 0;
+
+    while (data_sent < message_size)
+    {
+        ssize_t ret = send(sock, buffer + data_sent, message_size - data_sent, 0);
+        if (ret < 0)
+        {
+            if (errno==EINTR || errno==EAGAIN || errno==EWOULDBLOCK)
+            {
+                // Temporary error.
+                dlt_vlog(LOG_INFO,"dlt_daemon_socket_sendreliable: socket sending failed [errno: %d], trying again.\n", errno);
+            }
+            else
+            {
+                dlt_vlog(LOG_WARNING,"dlt_daemon_socket_sendreliable: socket send failed [errno: %d]!\n", errno);
+                return DLT_DAEMON_ERROR_SEND_FAILED;
+            }
+        }
+        data_sent += ret;
+    }
     return DLT_DAEMON_ERROR_OK;
 }
 
diff --git a/src/daemon/dlt_daemon_socket.h b/src/daemon/dlt_daemon_socket.h
index cc8dfb5..a7f9ca6 100644
--- a/src/daemon/dlt_daemon_socket.h
+++ b/src/daemon/dlt_daemon_socket.h
@@ -69,4 +69,13 @@ int dlt_daemon_socket_get_send_qeue_max_size(int sock);
 
 int dlt_daemon_socket_send(int sock,void* data1,int size1,void* data2,int size2,char serialheader);
 
+/**
+ * @brief dlt_daemon_socket_sendreliable - sends data to socket with additional checks and resending functionality - trying to be reliable
+ * @param sock
+ * @param buffer
+ * @param message_size
+ * @return on sucess: DLT_DAEMON_ERROR_OK, on error: DLT_DAEMON_ERROR_SEND_FAILED
+ */
+int dlt_daemon_socket_sendreliable(int sock, void* buffer,int  message_size);
+
 #endif /* DLT_DAEMON_SOCKET_H */