[fcoe] Request SPMA iff FIP advertisement indicates support for SPMA

We currently set both the FP and SP bits in our FIP FLOGI, to allow
the FCF the choice of selecting either a fabric-provided or a server-
provided MAC address.  This complies with the FCoE specification, but
has been observed to result in an FLOGI rejection from some FCFs.

Fix by recording whether or not the FCF supports SPMA, and requesting
only one of FPMA or SPMA in our FIP FLOGI.  We choose to prefer SPMA
where available, because many iPXE drivers will not be able to receive
unicast packets sent to a non-default MAC address.

Reported-by: Hadar Hen Zion <hadarh@mellanox.co.il>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/fcoe.c

@@ -101,6 +101,8 @@ enum fcoe_flags {
 	FCOE_HAVE_FCF = 0x0002,
 	/** We have a FIP-capable FCoE forwarder available to be used */
 	FCOE_HAVE_FIP_FCF = 0x0004,
+	/** FCoE forwarder supports server-provided MAC addresses */
+	FCOE_FCF_ALLOWS_SPMA = 0x0008,
 };
 
 struct net_protocol fcoe_protocol __net_protocol;
@@ -228,8 +230,10 @@ static int fcoe_deliver ( struct fcoe_port *fcoe,
 		memset ( fipmac, 0, sizeof ( *fipmac ) );
 		fipmac->type = FIP_MAC_ADDRESS;
 		fipmac->len = ( sizeof ( *fipmac ) / 4 );
-		memcpy ( fipmac->mac, fcoe->netdev->ll_addr,
-			 sizeof ( fipmac->mac ) );
+		if ( fcoe->flags & FCOE_FCF_ALLOWS_SPMA ) {
+			memcpy ( fipmac->mac, fcoe->netdev->ll_addr,
+				 sizeof ( fipmac->mac ) );
+		}
 
 		/* Create FIP header */
 		fiphdr = iob_push ( iobuf, sizeof ( *fiphdr ) );
@@ -239,7 +243,8 @@ static int fcoe_deliver ( struct fcoe_port *fcoe,
 		fiphdr->subcode = FIP_ELS_REQUEST;
 		fiphdr->len =
 			htons ( ( iob_len ( iobuf ) - sizeof ( *fiphdr ) ) / 4);
-		fiphdr->flags = htons ( FIP_FP | FIP_SP );
+		fiphdr->flags = ( ( fcoe->flags & FCOE_FCF_ALLOWS_SPMA ) ?
+				  htons ( FIP_SP ) : htons ( FIP_FP ) );
 
 		/* Send as FIP packet from netdev's own MAC address */
 		net_protocol = &fip_protocol;
@@ -636,17 +641,23 @@ static int fcoe_fip_rx_advertisement ( struct fcoe_port *fcoe,
 			} else {
 				fcoe->keepalive = ntohl ( fka_adv_p->period );
 			}
+			fcoe->flags &= ~FCOE_FCF_ALLOWS_SPMA;
+			if ( flags & FIP_SP )
+				fcoe->flags |= FCOE_FCF_ALLOWS_SPMA;
 			memcpy ( fcoe->fcf_mac, mac_address->mac,
 				 sizeof ( fcoe->fcf_mac ) );
 			DBGC ( fcoe, "FCoE %s selected FCF %s (priority %d, ",
 			       fcoe->netdev->name, eth_ntoa ( fcoe->fcf_mac ),
 			       fcoe->priority );
 			if ( fcoe->keepalive ) {
-				DBGC ( fcoe, "keepalive %dms)\n",
+				DBGC ( fcoe, "keepalive %dms",
 				       fcoe->keepalive );
 			} else {
-				DBGC ( fcoe, "no keepalive)\n" );
+				DBGC ( fcoe, "no keepalive" );
 			}
+			DBGC ( fcoe, ", %cPMA)\n",
+			       ( ( fcoe->flags & FCOE_FCF_ALLOWS_SPMA ) ?
+				 'S' : 'F' ) );
 		}
 
 	} else if ( fcoe->flags & FCOE_HAVE_FIP_FCF ) {
@@ -704,6 +715,8 @@ static int fcoe_fip_rx_els_response ( struct fcoe_port *fcoe,
 
 	/* Record local MAC address */
 	memcpy ( fcoe->local_mac, mac_address->mac, sizeof ( fcoe->local_mac ));
+	DBGC ( fcoe, "FCoE %s using local MAC %s\n",
+	       fcoe->netdev->name, eth_ntoa ( fcoe->local_mac ) );
 
 	/* Hand off via transport interface */
 	frame = &flogi->fc;