lwip: Add LwIP-based TCP/IP translator

* Makefile (prog-subdirs): Add lwip.
* config.make.in (HAVE_LIBLWIP, liblwip_CFLAGS, liblwip_LIBS): Define
variables.
* configure.ac: Check for liblwip.
* lwip/: New directory.

1 files changed, 65 insertions, 0 deletions

diff --git a/lwip/port/include/netif/hurdtunif.h b/lwip/port/include/netif/hurdtunif.h
new file mode 100644
index 00000000..938465bb
--- /dev/null
+++ b/lwip/port/include/netif/hurdtunif.h
@@ -0,0 +1,65 @@
+/*
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   Written by Joan Lledó.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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 2, or (at
+   your option) any later version.
+
+   The GNU Hurd 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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/* Tunnel devices module */
+
+#ifndef LWIP_HURDTUNIF_H
+#define LWIP_HURDTUNIF_H
+
+#include <hurd/ports.h>
+
+#include <lwip/netif.h>
+#include <netif/ifcommon.h>
+
+/* Queue of data in the tunnel */
+struct pbufqueue
+{
+  struct pbuf *head;
+  struct pbuf **tail;
+  uint8_t len;
+};
+
+/* Extension of the common device interface to store tunnel metadata */
+struct hurdtunif
+{
+  struct ifcommon comm;
+
+  struct trivfs_control *cntl;	/* Identify the tunnel device in use */
+  file_t underlying;		/* Underlying node where the tunnel is bound */
+  struct iouser *user;		/* Restrict the access to one user at a time */
+  struct pbufqueue queue;	/* Output queue */
+
+  /* Concurrent access to the queue */
+  pthread_mutex_t lock;
+  pthread_cond_t read;
+  pthread_cond_t select;
+  uint8_t read_blocked;
+};
+
+struct port_class *tunnel_cntlclass;
+struct port_class *tunnel_class;
+
+/* Device initialization */
+error_t hurdtunif_device_init (struct netif *netif);
+
+/* Module initialization */
+error_t hurdtunif_module_init ();
+
+#endif /* LWIP_HURDTUNIF_H */