tipc: improve and extend media address conversion functions

TIPC currently handles two media specific addresses: Ethernet MAC
addresses and InfiniBand addresses. Those are kept in three different
formats:

1) A "raw" format as obtained from the device. This format is known
   only by the media specific adapter code in eth_media.c and
   ib_media.c.
2) A "generic" internal format, in the form of struct tipc_media_addr,
   which can be referenced and passed around by the generic media-
   unaware code.
3) A serialized version of the latter, to be conveyed in neighbor
   discovery messages.

Conversion between the three formats can only be done by the media
specific code, so we have function pointers for this purpose in
struct tipc_media. Here, the media adapters can install their own
conversion functions at startup.

We now introduce a new such function, 'raw2addr()', whose purpose
is to convert from format 1 to format 2 above. We also try to as far
as possible uniform commenting, variable names and usage of these
functions, with the purpose of making them more comprehensible.

We can now also remove the function tipc_l2_media_addr_set(), whose
job is done better by the new function.

Finally, we expand the field for serialized addresses (format 3)
in discovery messages from 20 to 32 bytes. This is permitted
according to the spec, and reduces the risk of problems when we
add new media in the future.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 19 deletions

diff --git a/net/tipc/eth_media.c b/net/tipc/eth_media.c
index 67cf3f9..5e1426f 100644
--- a/net/tipc/eth_media.c
+++ b/net/tipc/eth_media.c
@@ -1,7 +1,7 @@
 /*
  * net/tipc/eth_media.c: Ethernet bearer support for TIPC
  *
- * Copyright (c) 2001-2007, 2013, Ericsson AB
+ * Copyright (c) 2001-2007, 2013-2014, Ericsson AB
  * Copyright (c) 2005-2008, 2011-2013, Wind River Systems
  * All rights reserved.
  *
@@ -37,39 +37,52 @@
 #include "core.h"
 #include "bearer.h"
 
-#define ETH_ADDR_OFFSET	4	/* message header offset of MAC address */
+#define ETH_ADDR_OFFSET  4  /* MAC addr position inside address field */
 
-/* convert Ethernet address to string */
-static int tipc_eth_addr2str(struct tipc_media_addr *a, char *str_buf,
-			     int str_size)
+/* Convert Ethernet address (media address format) to string */
+static int tipc_eth_addr2str(struct tipc_media_addr *addr,
+			     char *strbuf, int bufsz)
 {
-	if (str_size < 18)	/* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
+	if (bufsz < 18)	/* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
 		return 1;
 
-	sprintf(str_buf, "%pM", a->value);
+	sprintf(strbuf, "%pM", addr->value);
 	return 0;
 }
 
-/* convert Ethernet address format to message header format */
-static int tipc_eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
+/* Convert from media address format to discovery message addr format */
+static int tipc_eth_addr2msg(char *msg, struct tipc_media_addr *addr)
 {
-	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->value, ETH_ALEN);
+	memset(msg, 0, TIPC_MEDIA_ADDR_SIZE);
+	msg[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
+	memcpy(msg + ETH_ADDR_OFFSET, addr->value, ETH_ALEN);
 	return 0;
 }
 
-/* convert message header address format to Ethernet format */
-static int tipc_eth_msg2addr(const struct tipc_bearer *tb_ptr,
-			     struct tipc_media_addr *a, char *msg_area)
+/* Convert raw mac address format to media addr format */
+static int tipc_eth_raw2addr(struct tipc_bearer *b,
+			     struct tipc_media_addr *addr,
+			     char *msg)
 {
-	if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
-		return 1;
+	char bcast_mac[ETH_ALEN] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
 
-	tipc_l2_media_addr_set(tb_ptr, a, msg_area + ETH_ADDR_OFFSET);
+	memset(addr, 0, sizeof(*addr));
+	ether_addr_copy(addr->value, msg);
+	addr->media_id = TIPC_MEDIA_TYPE_ETH;
+	addr->broadcast = !memcmp(addr->value, bcast_mac, ETH_ALEN);
 	return 0;
 }
 
+/* Convert discovery msg addr format to Ethernet media addr format */
+static int tipc_eth_msg2addr(struct tipc_bearer *b,
+			     struct tipc_media_addr *addr,
+			     char *msg)
+{
+	/* Skip past preamble: */
+	msg += ETH_ADDR_OFFSET;
+	return tipc_eth_raw2addr(b, addr, msg);
+}
+
 /* Ethernet media registration info */
 struct tipc_media eth_media_info = {
 	.send_msg	= tipc_l2_send_msg,
@@ -78,6 +91,7 @@ struct tipc_media eth_media_info = {
 	.addr2str	= tipc_eth_addr2str,
 	.addr2msg	= tipc_eth_addr2msg,
 	.msg2addr	= tipc_eth_msg2addr,
+	.raw2addr	= tipc_eth_raw2addr,
 	.priority	= TIPC_DEF_LINK_PRI,
 	.tolerance	= TIPC_DEF_LINK_TOL,
 	.window		= TIPC_DEF_LINK_WIN,
@@ -85,4 +99,3 @@ struct tipc_media eth_media_info = {
 	.hwaddr_len	= ETH_ALEN,
 	.name		= "eth"
 };
-