Implement flow control for http.

* grub-core/net/http.c (parse_line): Handle response 206.
	(http_receive): Stall if too many packets are in the queue.
	(http_establish): Fix range header.
	(http_seek): Fix double free.
	(http_close): Likewise.
	(http_packets_pulled): New function.
	(grub_http_protocol): Set http_seek
	* grub-core/net/tcp.c (grub_net_tcp_socket): New field `i_stall'.
	(ack_real): Set window depending on i_stall.
	(grub_net_send_tcp_packet): Likewise.
	(grub_net_tcp_stall): New function.
	(grub_net_tcp_unstall): Likewise.
	* include/grub/net/tcp.h (grub_net_tcp_stall): New proto.
	(grub_net_tcp_unstall): Likewise.

ChangeLog

@@ -1,3 +1,22 @@
+2012-06-22  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	Implement flow control for http.
+
+	* grub-core/net/http.c (parse_line): Handle response 206.
+	(http_receive): Stall if too many packets are in the queue.
+	(http_establish): Fix range header.
+	(http_seek): Fix double free.
+	(http_close): Likewise.
+	(http_packets_pulled): New function.
+	(grub_http_protocol): Set http_seek
+	* grub-core/net/tcp.c (grub_net_tcp_socket): New field `i_stall'.
+	(ack_real): Set window depending on i_stall.
+	(grub_net_send_tcp_packet): Likewise.
+	(grub_net_tcp_stall): New function.
+	(grub_net_tcp_unstall): Likewise.
+	* include/grub/net/tcp.h (grub_net_tcp_stall): New proto.
+	(grub_net_tcp_unstall): Likewise.
+
 2012-06-22  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* grub-core/net/tftp.c: Decrease stall to 50 packets.

grub-core/net/http.c

@@ -101,8 +101,11 @@ parse_line (grub_file_t file, http_data_t data, char *ptr, grub_size_t len)
     {
       int code;
       if (grub_memcmp (ptr, "HTTP/1.1 ", sizeof ("HTTP/1.1 ") - 1) != 0)
-	return grub_error (GRUB_ERR_NET_INVALID_RESPONSE,
+	{
-			   N_("unsupported HTTP response"));
+	  data->errmsg = grub_strdup (_("unsupported HTTP response"));
+	  data->first_line_recv = 1;
+	  return GRUB_ERR_NONE;
+	}
       ptr += sizeof ("HTTP/1.1 ") - 1;
       code = grub_strtoul (ptr, &ptr, 10);
       if (grub_errno)
@@ -110,6 +113,7 @@ parse_line (grub_file_t file, http_data_t data, char *ptr, grub_size_t len)
       switch (code)
 	{
 	case 200:
+	case 206:
 	  break;
 	case 404:
 	  data->err = GRUB_ERR_FILE_NOT_FOUND;
@@ -262,6 +266,12 @@ http_receive (grub_net_tcp_socket_t sock __attribute__ ((unused)),
 	    < nb->tail - nb->data))
 	{
 	  grub_net_put_packet (&file->device->net->packs, nb);
+	  if (file->device->net->packs.count >= 20)
+	    file->device->net->stall = 1;
+
+	  if (file->device->net->packs.count >= 100)
+	    grub_net_tcp_stall (data->sock);
+
 	  if (data->chunked)
 	    data->chunk_rem -= nb->tail - nb->data;
 	  return GRUB_ERR_NONE;
@@ -274,6 +284,12 @@ http_receive (grub_net_tcp_socket_t sock __attribute__ ((unused)),
 	    return grub_errno;
 	  grub_netbuff_put (nb2, data->chunk_rem);
 	  grub_memcpy (nb2->data, nb->data, data->chunk_rem);
+	  if (file->device->net->packs.count >= 20)
+	    {
+	      file->device->net->stall = 1;
+	      grub_net_tcp_stall (data->sock);
+	    }
+
 	  grub_net_put_packet (&file->device->net->packs, nb2);
 	  grub_netbuff_pull (nb, data->chunk_rem);
 	}
@@ -297,9 +313,8 @@ http_establish (struct grub_file *file, grub_off_t offset, int initial)
 			   + grub_strlen (file->device->net->server)
 			   + sizeof ("\r\nUser-Agent: " PACKAGE_STRING
 				     "\r\n") - 1
-			   + sizeof ("Content-Range: bytes XXXXXXXXXXXXXXXXXXXX"
+			   + sizeof ("Range: bytes=XXXXXXXXXXXXXXXXXXXX"
-				     "-XXXXXXXXXXXXXXXXXXXX/"
+				     "-\r\n\r\n"));
-				     "XXXXXXXXXXXXXXXXXXXX\r\n\r\n"));
   if (!nb)
     return grub_errno;
 
@@ -358,12 +373,11 @@ http_establish (struct grub_file *file, grub_off_t offset, int initial)
     {
       ptr = nb->tail;
       grub_snprintf ((char *) ptr,
-		     sizeof ("Content-Range: bytes XXXXXXXXXXXXXXXXXXXX-"
+		     sizeof ("Range: bytes=XXXXXXXXXXXXXXXXXXXX-"
-			     "XXXXXXXXXXXXXXXXXXXX/XXXXXXXXXXXXXXXXXXXX\r\n"
+			     "\r\n"
 			     "\r\n"),
-		     "Content-Range: bytes %" PRIuGRUB_UINT64_T "-%"
+		     "Range: bytes=%" PRIuGRUB_UINT64_T "-\r\n\r\n",
-		     PRIuGRUB_UINT64_T "/%" PRIuGRUB_UINT64_T "\r\n\r\n",
+		     offset);
-		     offset, file->size - 1, file->size);
       grub_netbuff_put (nb, grub_strlen ((char *) ptr));
     }
   ptr = nb->tail;
@@ -403,6 +417,7 @@ http_establish (struct grub_file *file, grub_off_t offset, int initial)
 	  char *str = data->errmsg;
 	  err = grub_error (data->err, "%s", str);
 	  grub_free (str);
+	  data->errmsg = 0;
 	  return data->err;
 	}
       return grub_error (GRUB_ERR_TIMEOUT, N_("time out opening `%s'"), data->filename);
@@ -418,6 +433,7 @@ http_seek (struct grub_file *file, grub_off_t off)
   old_data = file->data;
   /* FIXME: Reuse socket?  */
   grub_net_tcp_close (old_data->sock, GRUB_NET_TCP_ABORT);
+  old_data->sock = 0;
 
   while (file->device->net->packs.first)
     {
@@ -425,6 +441,7 @@ http_seek (struct grub_file *file, grub_off_t off)
       grub_net_remove_packet (file->device->net->packs.first);
     }
 
+  file->device->net->stall = 0;
   file->device->net->offset = off;
 
   data = grub_zalloc (sizeof (*data));
@@ -436,6 +453,7 @@ http_seek (struct grub_file *file, grub_off_t off)
   if (!data->filename)
     {
       grub_free (data);
+      file->data = 0;
       return grub_errno;
     }
   grub_free (old_data);
@@ -446,6 +464,7 @@ http_seek (struct grub_file *file, grub_off_t off)
     {
       grub_free (data->filename);
       grub_free (data);
+      file->data = 0;
       return err;
     }
   return GRUB_ERR_NONE;
@@ -488,20 +507,39 @@ http_close (struct grub_file *file)
 {
   http_data_t data = file->data;
 
+  if (!data)
+    return GRUB_ERR_NONE;
+
   if (data->sock)
     grub_net_tcp_close (data->sock, GRUB_NET_TCP_ABORT);
   if (data->current_line)
     grub_free (data->current_line);
+  grub_free (data->filename);
   grub_free (data);
   return GRUB_ERR_NONE;
 }
 
+static grub_err_t
+http_packets_pulled (struct grub_file *file)
+{
+  http_data_t data = file->data;
+
+  if (file->device->net->packs.count >= 20)
+    return 0;
+
+  if (!file->device->net->eof)
+    file->device->net->stall = 0;
+  grub_net_tcp_unstall (data->sock);
+  return 0;
+}
+
 static struct grub_net_app_protocol grub_http_protocol = 
   {
     .name = "http",
     .open = http_open,
     .close = http_close,
-    .seek = http_seek
+    .seek = http_seek,
+    .packets_pulled = http_packets_pulled
   };
 
 GRUB_MOD_INIT (http)

grub-core/net/tcp.c

@@ -60,6 +60,7 @@ struct grub_net_tcp_socket
   int errors;
   int they_reseted;
   int i_reseted;
+  int i_stall;
   grub_uint32_t my_start_seq;
   grub_uint32_t my_cur_seq;
   grub_uint32_t their_start_seq;
@@ -331,7 +332,8 @@ ack_real (grub_net_tcp_socket_t sock, int res)
     {
       tcph_ack->ack = grub_cpu_to_be32 (sock->their_cur_seq);
       tcph_ack->flags = grub_cpu_to_be16_compile_time ((5 << 12) | TCP_ACK);
-      tcph_ack->window = grub_cpu_to_be16 (sock->my_window);
+      tcph_ack->window = !sock->i_stall ? grub_cpu_to_be16 (sock->my_window)
+	: 0;
     }
   tcph_ack->urgent = 0;
   tcph_ack->src = grub_cpu_to_be16 (sock->in_port);
@@ -707,7 +709,8 @@ grub_net_send_tcp_packet (const grub_net_tcp_socket_t socket,
       tcph = (struct tcphdr *) nb2->data;
       tcph->ack = grub_cpu_to_be32 (socket->their_cur_seq);
       tcph->flags = grub_cpu_to_be16_compile_time ((5 << 12) | TCP_ACK);
-      tcph->window = grub_cpu_to_be16 (socket->my_window);
+      tcph->window = !socket->i_stall ? grub_cpu_to_be16 (socket->my_window)
+	: 0;
       tcph->urgent = 0;
       err = grub_netbuff_put (nb2, fraglen);
       if (err)
@@ -730,7 +733,7 @@ grub_net_send_tcp_packet (const grub_net_tcp_socket_t socket,
   tcph->ack = grub_cpu_to_be32 (socket->their_cur_seq);
   tcph->flags = (grub_cpu_to_be16_compile_time ((5 << 12) | TCP_ACK)
 		 | (push ? grub_cpu_to_be16_compile_time (TCP_PUSH) : 0));
-  tcph->window = grub_cpu_to_be16 (socket->my_window);
+  tcph->window = !socket->i_stall ? grub_cpu_to_be16 (socket->my_window) : 0;
   tcph->urgent = 0;
   return tcp_send (nb, socket);
 }
@@ -975,3 +978,21 @@ grub_net_recv_tcp_packet (struct grub_net_buff *nb,
   grub_netbuff_free (nb);
   return GRUB_ERR_NONE;
 }
+
+void
+grub_net_tcp_stall (grub_net_tcp_socket_t sock)
+{
+  if (sock->i_stall)
+    return;
+  sock->i_stall = 1;
+  ack (sock);
+}
+
+void
+grub_net_tcp_unstall (grub_net_tcp_socket_t sock)
+{
+  if (!sock->i_stall)
+    return;
+  sock->i_stall = 0;
+  ack (sock);
+}

include/grub/net/tcp.h

@@ -76,4 +76,10 @@ grub_net_tcp_accept (grub_net_tcp_socket_t sock,
 				       void *data),
 		     void *hook_data);
 
+void
+grub_net_tcp_stall (grub_net_tcp_socket_t sock);
+
+void
+grub_net_tcp_unstall (grub_net_tcp_socket_t sock);
+
 #endif