[netdevice] Add the concept of an "Ethernet-compatible" MAC address

The iBFT is Ethernet-centric in providing only six bytes for a MAC
address.  This is most probably an indirect consequence of a similar
design flaw in the Windows NDIS stack.  (The WinOF IPoIB stack
performs all sorts of contortions in order to pretend to the NDIS
layer that it is dealing with six-byte MAC addresses.)

There is no sensible way in which to extend the iBFT without breaking
compatibility with programs that expect to parse it.  Add the notion
of an "Ethernet-compatible" MAC address to our link layer abstraction,
so that link layers can provide their own workarounds for this
limitation.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/net/ethernet.c b/src/net/ethernet.c
index e8daf9f9..79ed1dc6 100644
--- a/src/net/ethernet.c
+++ b/src/net/ethernet.c
@@ -148,6 +148,17 @@ int eth_mc_hash ( unsigned int af, const void *net_addr, void *ll_addr ) {
 	}
 }
 
+/**
+ * Generate Ethernet-compatible compressed link-layer address
+ *
+ * @v ll_addr		Link-layer address
+ * @v eth_addr		Ethernet-compatible address to fill in
+ */
+int eth_eth_addr ( const void *ll_addr, void *eth_addr ) {
+	memcpy ( eth_addr, ll_addr, ETH_ALEN );
+	return 0;
+}
+
 /** Ethernet protocol */
 struct ll_protocol ethernet_protocol __ll_protocol = {
 	.name		= "Ethernet",
@@ -160,6 +171,7 @@ struct ll_protocol ethernet_protocol __ll_protocol = {
 	.init_addr	= eth_init_addr,
 	.ntoa		= eth_ntoa,
 	.mc_hash	= eth_mc_hash,
+	.eth_addr	= eth_eth_addr,
 };
 
 /**