tipc: Add new address conversion routines for Ethernet media

Enhances TIPC's Ethernet media support to provide 3 new address conversion
routines, which allow TIPC to interpret an address that is in string form
and to convert an address to and from the 20 byte format used in TIPC's
neighbor discovery messages.

These routines are pre-requisites to a follow on commit that hides all
media-specific addressing details from TIPC's generic bearer code.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/net/tipc/eth_media.c b/net/tipc/eth_media.c
index 67f616a..ebba0fc 100644
--- a/net/tipc/eth_media.c
+++ b/net/tipc/eth_media.c
@@ -39,6 +39,8 @@
 
 #define MAX_ETH_BEARERS		MAX_BEARERS
 
+#define ETH_ADDR_OFFSET	4	/* message header offset of MAC address */
+
 /**
  * struct eth_bearer - Ethernet bearer data structure
  * @bearer: ptr to associated "generic" bearer structure
@@ -57,6 +59,16 @@
 static struct notifier_block notifier;
 
 /**
+ * eth_media_addr_set - initialize Ethernet media address structure
+ */
+
+static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
+{
+	a->type = htonl(TIPC_MEDIA_TYPE_ETH);
+	memcpy(&a->dev_addr.eth_addr, mac, ETH_ALEN);
+}
+
+/**
  * send_msg - send a TIPC message out over an Ethernet interface
  */
 
@@ -169,8 +181,7 @@
 	tb_ptr->usr_handle = (void *)eb_ptr;
 	tb_ptr->mtu = dev->mtu;
 	tb_ptr->blocked = 0;
-	tb_ptr->addr.type = htonl(TIPC_MEDIA_TYPE_ETH);
-	memcpy(&tb_ptr->addr.dev_addr, dev->dev_addr, ETH_ALEN);
+	eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
 	return 0;
 }
 
@@ -254,6 +265,51 @@
 	return 0;
 }
 
+/**
+ * eth_str2addr - convert string to Ethernet address
+ */
+
+static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
+{
+	char mac[ETH_ALEN];
+	int r;
+
+	r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
+		       (u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
+		       (u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
+
+	if (r != ETH_ALEN)
+		return 1;
+
+	eth_media_addr_set(a, mac);
+	return 0;
+}
+
+/**
+ * eth_str2addr - convert Ethernet address format to message header format
+ */
+
+static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
+{
+	memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
+	msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
+	memcpy(msg_area + ETH_ADDR_OFFSET, a->dev_addr.eth_addr, ETH_ALEN);
+	return 0;
+}
+
+/**
+ * eth_str2addr - convert message header address format to Ethernet format
+ */
+
+static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
+{
+	if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
+		return 1;
+
+	eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
+	return 0;
+}
+
 /*
  * Ethernet media registration info
  */
@@ -263,6 +319,9 @@
 	.enable_bearer	= enable_bearer,
 	.disable_bearer	= disable_bearer,
 	.addr2str	= eth_addr2str,
+	.str2addr	= eth_str2addr,
+	.addr2msg	= eth_addr2msg,
+	.msg2addr	= eth_msg2addr,
 	.bcast_addr	= { htonl(TIPC_MEDIA_TYPE_ETH),
 			    { {0xff, 0xff, 0xff, 0xff, 0xff, 0xff} } },
 	.priority	= TIPC_DEF_LINK_PRI,