Restructure

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 171 insertions, 0 deletions

diff --git a/src/communication.c b/src/communication.c
new file mode 100644
index 0000000..c508992
--- /dev/null
+++ b/src/communication.c
@@ -0,0 +1,171 @@
+/**
+ * coopgammad -- Cooperative gamma server
+ * Copyright (C) 2016  Mattias Andrée (maandree@kth.se)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "communication.h"
+#include "state.h"
+#include "coopgamma-server/server.h"
+
+#include <sys/socket.h>
+#include <errno.h>
+#include <string.h>
+
+
+
+/**
+ * Send a message
+ * 
+ * @param   conn  The index of the connection
+ * @param   buf   The data to send
+ * @param   n     The size of `buf`
+ * @return        Zero on success, -1 on error, 1 if disconncted
+ *                EINTR, EAGAIN, EWOULDBLOCK, and ECONNRESET count
+ *                as success (ECONNRESET cause 1 to be returned),
+ *                and are handled appropriately.
+ */
+int send_message(size_t conn, char* restrict buf, size_t n)
+{
+  struct ring* restrict ring = outbound + conn;
+  int fd = connections[conn];
+  int saved_errno;
+  size_t ptr = 0;
+  ssize_t sent;
+  size_t chunksize = n;
+  size_t sendsize;
+  size_t old_n;
+  char* old_buf;
+    
+  while ((old_buf = ring_peek(ring, &old_n)))
+    {
+      size_t old_ptr = 0;
+      while (old_ptr < n)
+	{
+	  sendsize = old_n - old_ptr < chunksize ? old_n - old_ptr : chunksize;
+	  sent = send(fd, old_buf + old_ptr, sendsize, 0);
+	  if (sent < 0)
+	    {
+	      if (errno != EMSGSIZE)
+		goto fail;
+	      chunksize >>= 1;
+	      if (chunksize == 0)
+		goto fail;
+	      continue;
+	    }
+	  old_ptr += (size_t)sent;
+	  ring_pop(ring, (size_t)sent);
+	}
+    }
+  
+  while (ptr < n)
+    {
+      sendsize = n - ptr < chunksize ? n - ptr : chunksize;
+      sent = send(fd, buf + ptr, sendsize, 0);
+      if (sent < 0)
+	{
+	  if (errno != EMSGSIZE)
+	    goto fail;
+	  chunksize >>= 1;
+	  if (chunksize == 0)
+	    goto fail;
+	  continue;
+	}
+      ptr += (size_t)sent;
+    }
+  
+  free(buf);
+  return 0;
+  
+ fail:
+  switch (errno)
+    {
+    case EINTR:
+    case EAGAIN:
+#if EAGAIN != EWOULDBLOCK
+    case EWOULDBLOCK:
+#endif
+      if (ring_push(ring, buf + ptr, n - ptr) < 0)
+	goto proper_fail;
+      free(buf);
+      return 0;
+    case ECONNRESET:
+      free(buf);
+      if (connection_closed(fd) < 0)
+	return -1;
+      return 1;
+    default:
+      break;
+    }
+ proper_fail:
+  saved_errno = errno;
+  free(buf);
+  errno = saved_errno;
+  return -1;
+}
+
+
+/**
+ * Send a custom error without an error number
+ * 
+ * @param   conn        The index of the connection
+ * @param   message_id  The ID of the message to which this message is a response
+ * @param   desc        The error description to send
+ * @return              1: Client disconnected
+ *                      0: Success (possibily delayed)
+ *                      -1: An error occurred
+ */
+int (send_error)(size_t conn, const char* restrict message_id, const char* restrict desc)
+{
+  char* restrict buf;
+  size_t n;
+  
+  MAKE_MESSAGE(&buf, &n, 0,
+	       "Command: error\n"
+	       "In response to: %s\n"
+	       "Error: custom\n"
+	       "Length: %zu\n"
+	       "\n"
+	       "%s\n",
+	       message_id, strlen(desc) + 1, desc);
+  
+  return send_message(conn, buf, n);
+}
+
+
+/**
+ * Send a standard error
+ * 
+ * @param   conn        The index of the connection
+ * @param   message_id  The ID of the message to which this message is a response
+ * @param   number      The value of `errno`, 0 to indicate success
+ * @return              1: Client disconnected
+ *                      0: Success (possibily delayed)
+ *                      -1: An error occurred
+ */
+int (send_errno)(size_t conn, const char* restrict message_id, int number)
+{
+  char* restrict buf;
+  size_t n;
+  
+  MAKE_MESSAGE(&buf, &n, 0,
+	       "Command: error\n"
+	       "In response to: %s\n"
+	       "Error: %i\n"
+	       "\n",
+	       message_id, number);
+  
+  return send_message(conn, buf, n);
+}
+