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, 112 insertions, 0 deletions

diff --git a/lwip/port/netif/hurdloopif.c b/lwip/port/netif/hurdloopif.c
new file mode 100644
index 00000000..ef64b8b6
--- /dev/null
+++ b/lwip/port/netif/hurdloopif.c
@@ -0,0 +1,112 @@
+/*
+   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/>.
+*/
+
+/* Loopback devices module */
+
+#include <netif/hurdloopif.h>
+
+#include <net/if.h>
+#include <net/if_arp.h>
+#include <string.h>
+
+#include <lwip-util.h>
+
+/* Set the device flags */
+static error_t
+hurdloopif_device_set_flags (struct netif *netif, uint16_t flags)
+{
+  error_t err = 0;
+  hurdloopif *loopif;
+
+  loopif = netif_get_state (netif);
+  loopif->flags = flags;
+
+  return err;
+}
+
+/*
+ * Update the interface's MTU
+ */
+static error_t
+hurdloopif_device_update_mtu (struct netif *netif, uint32_t mtu)
+{
+  error_t err = 0;
+
+  netif->mtu = mtu;
+
+  return err;
+}
+
+/*
+ * Release all resources of this netif.
+ *
+ * Returns 0 on success.
+ */
+static error_t
+hurdloopif_device_terminate (struct netif *netif)
+{
+  /* Free the hook */
+  free (netif_get_state (netif)->devname);
+  free (netif_get_state (netif));
+
+  return 0;
+}
+
+/*
+ * Set up the LwIP loopback interface
+ */
+error_t
+hurdloopif_device_init (struct netif * netif)
+{
+  error_t err = 0;
+  hurdloopif *loopif;
+
+  /*
+   * Replace the hook by a new one with the proper size.
+   * The old one is in the stack and will be removed soon.
+   */
+  loopif = calloc (1, sizeof (hurdloopif));
+  if (loopif == NULL)
+    {
+      LWIP_DEBUGF (NETIF_DEBUG, ("hurdloopif_init: out of memory\n"));
+      return ERR_MEM;
+    }
+  memcpy (loopif, netif_get_state (netif), sizeof (struct ifcommon));
+  netif->state = loopif;
+
+  /* Device name and type */
+  loopif->devname = LOOP_DEV_NAME;
+  loopif->type = ARPHRD_LOOPBACK;
+
+  /* MTU = MSS + IP header + TCP header */
+  netif->mtu = TCP_MSS + 20 + 20;
+
+  /* Set flags */
+  hurdloopif_device_set_flags (netif, IFF_UP | IFF_RUNNING | IFF_LOOPBACK);
+
+  /* Set callbacks */
+  loopif->open = 0;
+  loopif->close = 0;
+  loopif->terminate = hurdloopif_device_terminate;
+  loopif->update_mtu = hurdloopif_device_update_mtu;
+  loopif->change_flags = hurdloopif_device_set_flags;
+
+  return err;
+}