From e3c7a1948d080a753aceb92c8bfed07dfdf3daac Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@ipxe.org>
Date: Sat, 31 Jul 2010 09:20:41 +0100
Subject: [PATCH] [dhcp] Allow multiple interfaces in dhcp command

The "dhcp" command now accepts a list of interfaces to try until one
succeeds.  For example:

 iPXE> dhcp net0 net1 net2

If no interfaces are specified, all interfaces will be tried.

Note that interfaces that fail to DHCP are closed in order to avoid
memory exhaustion.  This behavior differs from the previous "dhcp"
command implementation but should not affect any existing scripts
since a "dhcp" command failure would in any case cause the script to
abort.

Originally-implemented-by: Lars Kellogg-Stedman <lars@oddbit.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/hci/commands/dhcp_cmd.c | 78 ++++++++++++++++++++++++++-----------
 1 file changed, 56 insertions(+), 22 deletions(-)

diff --git a/src/hci/commands/dhcp_cmd.c b/src/hci/commands/dhcp_cmd.c
index 82869d62..6da0d637 100644
--- a/src/hci/commands/dhcp_cmd.c
+++ b/src/hci/commands/dhcp_cmd.c
@@ -45,12 +45,52 @@ FILE_LICENCE ( GPL2_OR_LATER );
  */
 static void dhcp_syntax ( char **argv ) {
 	printf ( "Usage:\n"
-		 "  %s <interface>\n"
+		 "  %s [<interface>] [<interface>...]\n"
 		 "\n"
 		 "Configure a network interface using DHCP\n",
 		 argv[0] );
 }
 
+/**
+ * Execute "dhcp" command for a network device
+ *
+ * @v netdev		Network device
+ * @ret rc		Exit code
+ */
+static int dhcp_exec_netdev ( struct net_device *netdev ) {
+	int rc;
+
+	if ( ( rc = dhcp ( netdev ) ) != 0 ) {
+		printf ( "Could not configure %s: %s\n",
+			 netdev->name, strerror ( rc ) );
+
+		/* Close device on failure, to avoid memory exhaustion */
+		netdev_close ( netdev );
+
+		return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * Execute "dhcp" command for a named network device
+ *
+ * @v netdev_name	Network device name
+ * @ret rc		Exit code
+ */
+static int dhcp_exec_name ( const char *netdev_name ) {
+	struct net_device *netdev;
+
+	netdev = find_netdev ( netdev_name );
+	if ( ! netdev ) {
+		printf ( "No such interface \"%s\"\n", netdev_name );
+		return 1;
+	}
+
+	return dhcp_exec_netdev ( netdev );
+}
+
 /**
  * The "dhcp" command
  *
@@ -63,7 +103,7 @@ static int dhcp_exec ( int argc, char **argv ) {
 		{ "help", 0, NULL, 'h' },
 		{ NULL, 0, NULL, 0 },
 	};
-	const char *netdev_txt;
+	const char *netdev_name;
 	struct net_device *netdev;
 	int c;
 	int rc;
@@ -80,28 +120,22 @@ static int dhcp_exec ( int argc, char **argv ) {
 		}
 	}
 
-	/* Need exactly one interface name remaining after the options */
-	if ( optind != ( argc - 1 ) ) {
-		dhcp_syntax ( argv );
-		return 1;
-	}
-	netdev_txt = argv[optind];
-
-	/* Parse arguments */
-	netdev = find_netdev ( netdev_txt );
-	if ( ! netdev ) {
-		printf ( "No such interface: %s\n", netdev_txt );
-		return 1;
+	if ( optind != argc ) {
+		/* Treat arguments as a list of interfaces to try */
+		while ( optind != argc ) {
+			netdev_name = argv[optind++];
+			if ( ( rc = dhcp_exec_name ( netdev_name ) ) == 0 )
+				return 0;
+		}
+	} else {
+		/* Try all interfaces */
+		for_each_netdev ( netdev ) {
+			if ( ( rc = dhcp_exec_netdev ( netdev ) ) == 0 )
+				return 0;
+		}
 	}
 
-	/* Perform DHCP */
-	if ( ( rc = dhcp ( netdev ) ) != 0 ) {
-		printf ( "Could not configure %s: %s\n", netdev->name,
-			 strerror ( rc ) );
-		return 1;
-	}
-
-	return 0;
+	return 1;
 }
 
 /**