1 files changed, 80 insertions, 7 deletions

diff --git a/src/usr/autoboot.c b/src/usr/autoboot.c
index 057b70cd0..45b3b6e7b 100644
--- a/src/usr/autoboot.c
+++ b/src/usr/autoboot.c
@@ -17,6 +17,7 @@
  */
 
 #include <string.h>
+#include <errno.h>
 #include <vsprintf.h>
 #include <gpxe/netdevice.h>
 #include <usr/ifmgmt.h>
@@ -30,21 +31,93 @@
 
 void test_dhcp ( struct net_device *netdev );
 
-void autoboot ( void ) {
+/**
+ * Identify the boot network device
+ *
+ * @ret netdev		Boot network device
+ */
+static struct net_device * find_boot_netdev ( void ) {
+	return NULL;
+}
+
+/**
+ * Get the next network device to try
+ *
+ * @ret netdev		'Next' network device
+ *
+ * This function will cycle through all registered network devices in
+ * order, returning NULL.
+ *
+ * This function should be safe against registration/deregistration of
+ * net devices between calls to next_netdev().
+ */
+static struct net_device * next_netdev ( void ) {
+	static struct net_device *last_netdev = NULL;
 	struct net_device *netdev;
-	int rc;
 
 	for_each_netdev ( netdev ) {
+		if ( ! last_netdev ) {
+			last_netdev = netdev;
+			return netdev;
+		}
+		if ( last_netdev == netdev )
+			last_netdev = NULL;
+	}
 
-		if ( ( rc = ifopen ( netdev ) ) != 0 )
-			continue;
+	last_netdev = NULL;
+	return NULL;
+}
+
+/**
+ * Boot from a network device
+ *
+ * @v netdev		Network device
+ */
+void netboot ( struct net_device *netdev ) {
+
+	/* Open device and display device status */
+	if ( ifopen ( netdev ) != 0 )
+		return;
+	ifstat ( netdev );
 
-		ifstat ( netdev );
+	test_dhcp ( netdev );
+}
+
+/**
+ * Close all open net devices
+ *
+ * Called before a fresh boot attempt in order to free up memory.  We
+ * don't just close the device immediately after the boot fails,
+ * because there may still be TCP connections in the process of
+ * closing.
+ */
+static void close_all_netdevs ( void ) {
+	struct net_device *netdev;
 
-		test_dhcp ( netdev );
-		
+	for_each_netdev ( netdev ) {
 		ifclose ( netdev );
 	}
+}
+
+/**
+ * Boot the system
+ */
+void autoboot ( void ) {
+	struct net_device *boot_netdev;
+	struct net_device *netdev;
+
+	/* If we have an identifable boot device, try that first */
+	close_all_netdevs();
+	if ( ( boot_netdev = find_boot_netdev() ) )
+		netboot ( boot_netdev );
+
+	/* If that fails, try booting from any of the other devices */
+	for_each_netdev ( netdev ) {
+		if ( netdev == boot_netdev )
+			continue;
+		close_all_netdevs();
+		netboot ( netdev );
+	}
 
 	printf ( "No more network devices\n" );
 }