[netdevice] Add "linktype" setting

Add a new setting to provide access to the link layer protocol type
from scripts.  This can be useful in order to skip configuring
interfaces based on their link layer protocol or, conversely,
configure only selected interface types (Ethernet, IPoIB, etc.)

Example script:

    set idx:int32 0
    :loop
    isset ${net${idx}/mac} || exit 0
    iseq ${net${idx}/linktype} IPoIB && goto try_next ||
    autoboot net${idx} ||
    :try_next
    inc idx && goto loop

Signed-off-by: Pavel Krotkiy <porsh@nebius.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

2 files changed, 24 insertions, 0 deletions

diff --git a/src/include/ipxe/settings.h b/src/include/ipxe/settings.h
index 424188deb..0301da12e 100644
--- a/src/include/ipxe/settings.h
+++ b/src/include/ipxe/settings.h
@@ -471,6 +471,8 @@ mac_setting __setting ( SETTING_NETDEV, mac );
 extern const struct setting
 busid_setting __setting ( SETTING_NETDEV, busid );
 extern const struct setting
+linktype_setting __setting ( SETTING_NETDEV, linktype );
+extern const struct setting
 user_class_setting __setting ( SETTING_HOST_EXTRA, user-class );
 extern const struct setting
 vendor_class_setting __setting ( SETTING_HOST_EXTRA, vendor-class );
diff --git a/src/net/netdev_settings.c b/src/net/netdev_settings.c
index fb98663ca..080b6d2a5 100644
--- a/src/net/netdev_settings.c
+++ b/src/net/netdev_settings.c
@@ -65,6 +65,11 @@ const struct setting busid_setting __setting ( SETTING_NETDEV, busid ) = {
 	.description = "Bus ID",
 	.type = &setting_type_hex,
 };
+const struct setting linktype_setting __setting ( SETTING_NETDEV, linktype ) = {
+	.name = "linktype",
+	.description = "Link-layer type",
+	.type = &setting_type_string,
+};
 const struct setting chip_setting __setting ( SETTING_NETDEV, chip ) = {
 	.name = "chip",
 	.description = "Chip",
@@ -220,6 +225,22 @@ static int netdev_fetch_busid ( struct net_device *netdev, void *data,
 }
 
 /**
+ * Fetch link layer type setting
+ *
+ * @v netdev		Network device
+ * @v data		Buffer to fill with setting data
+ * @v len		Length of buffer
+ * @ret len		Length of setting data, or negative error
+ */
+static int netdev_fetch_linktype ( struct net_device *netdev, void *data,
+				   size_t len ) {
+	const char *linktype = netdev->ll_protocol->name;
+
+	strncpy ( data, linktype, len );
+	return strlen ( linktype );
+}
+
+/**
  * Fetch chip setting
  *
  * @v netdev		Network device
@@ -281,6 +302,7 @@ static struct netdev_setting_operation netdev_setting_operations[] = {
 	{ &bustype_setting, NULL, netdev_fetch_bustype },
 	{ &busloc_setting, NULL, netdev_fetch_busloc },
 	{ &busid_setting, NULL, netdev_fetch_busid },
+	{ &linktype_setting, NULL, netdev_fetch_linktype },
 	{ &chip_setting, NULL, netdev_fetch_chip },
 	{ &ifname_setting, NULL, netdev_fetch_ifname },
 };