qeth: exploit source MAC address for inbound layer3 packets

OSA-devices operating in layer3 mode offer adding of the source MAC
address to the QDIO header of inbound packets. The qeth driver can
exploit this functionality to replace FAKELL-entries in the ethernet
header of received packets.
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core.h

@@ -643,7 +643,6 @@ struct qeth_card_options {
 	int macaddr_mode;
 	int fake_broadcast;
 	int add_hhlen;
-	int fake_ll;
 	int layer2;
 	enum qeth_large_send_types large_send;
 	int performance_stats;

drivers/s390/net/qeth_core_main.c

@@ -1072,7 +1072,6 @@ static void qeth_set_intial_options(struct qeth_card *card)
 	card->options.macaddr_mode = QETH_TR_MACADDR_NONCANONICAL;
 	card->options.fake_broadcast = 0;
 	card->options.add_hhlen = DEFAULT_ADD_HHLEN;
-	card->options.fake_ll = 0;
 	card->options.performance_stats = 0;
 	card->options.rx_sg_cb = QETH_RX_SG_CB;
 }

drivers/s390/net/qeth_l3_main.c

@@ -1207,12 +1207,9 @@ static int qeth_l3_start_ipa_source_mac(struct qeth_card *card)
 
 	QETH_DBF_TEXT(TRACE, 3, "stsrcmac");
 
-	if (!card->options.fake_ll)
-		return -EOPNOTSUPP;
-
 	if (!qeth_is_supported(card, IPA_SOURCE_MAC)) {
 		dev_info(&card->gdev->dev,
-			"Inbound source address not supported on %s\n",
+			"Inbound source MAC-address not supported on %s\n",
 			QETH_CARD_IFNAME(card));
 		return -EOPNOTSUPP;
 	}
@@ -1221,7 +1218,7 @@ static int qeth_l3_start_ipa_source_mac(struct qeth_card *card)
 					  IPA_CMD_ASS_START, 0);
 	if (rc)
 		dev_warn(&card->gdev->dev,
-			"Starting proxy ARP support for %s failed\n",
+			"Starting source MAC-address support for %s failed\n",
 			QETH_CARD_IFNAME(card));
 	return rc;
 }
@@ -1921,8 +1918,13 @@ static inline __u16 qeth_l3_rebuild_skb(struct qeth_card *card,
 			memcpy(tg_addr, card->dev->dev_addr,
 				card->dev->addr_len);
 		}
-		card->dev->header_ops->create(skb, card->dev, prot, tg_addr,
-					      "FAKELL", card->dev->addr_len);
+		if (hdr->hdr.l3.ext_flags & QETH_HDR_EXT_SRC_MAC_ADDR)
+			card->dev->header_ops->create(skb, card->dev, prot,
+				tg_addr, &hdr->hdr.l3.dest_addr[2],
+				card->dev->addr_len);
+		else
+			card->dev->header_ops->create(skb, card->dev, prot,
+				tg_addr, "FAKELL", card->dev->addr_len);
 	}
 
 #ifdef CONFIG_TR