include - Convert IP4 address class macros to inline functions

Change LOOPBACK MULTICAST LOCAL_MCAST BADCLASS and ZERONET macros to inline functions is_ip4_[type](__be32 addr) Adds some type safety and maybe some readability

No change in compiled image size

---

 include/linux/in.h |   45 ++++++++++++++++++++++++++++++++++++++++-----
 1 files changed, 40 insertions(+), 5 deletions(-)

index 3975cbf..ac6eff1 100644
@@ -246,12 +246,47 @@ struct sockaddr_in {
 #include <asm/byteorder.h> 
 
 #ifdef __KERNEL__
+
+static inline __be32 ip4_addr_octets(unsigned char a, unsigned char b, unsigned char c, unsigned char d)
+{
+	return htonl((((__u32)(a & 0xff)) << 24) |
+		     (((__u32)(b & 0xff)) << 16) |
+		     (((__u32)(c & 0xff)) << 8) |
+		     (((__u32)(d & 0xff)) << 0));
+}
+
+static inline bool is_ip4_loopback(__be32 addr)
+{
+	return (addr & ip4_addr_octets(255,0,0,0)) == ip4_addr_octets(127,0,0,0);
+}
+
+static inline bool is_ip4_multicast(__be32 addr)
+{
+	return (addr & ip4_addr_octets(240,0,0,0)) == ip4_addr_octets(224,0,0,0);
+}
+
+static inline bool is_ip4_local_multicast(__be32 addr)
+{
+	return (addr & ip4_addr_octets(255,255,255,0)) == ip4_addr_octets(224,0,0,0);
+}
+
+static inline bool is_ip4_badclass(__be32 addr)
+{
+	return (addr & ip4_addr_octets(240,0,0,0)) == ip4_addr_octets(240,0,0,0);
+}
+
+static inline bool is_ip4_zeronet(__be32 addr)
+{
+	return (addr & ip4_addr_octets(255,0,0,0)) == ip4_addr_octets(0,0,0,0);
+}
+
 /* Some random defines to make it easier in the kernel.. */
-#define LOOPBACK(x)	(((x) & htonl(0xff000000)) == htonl(0x7f000000))
-#define MULTICAST(x)	(((x) & htonl(0xf0000000)) == htonl(0xe0000000))
-#define BADCLASS(x)	(((x) & htonl(0xf0000000)) == htonl(0xf0000000))
-#define ZERONET(x)	(((x) & htonl(0xff000000)) == htonl(0x00000000))
-#define LOCAL_MCAST(x)	(((x) & htonl(0xFFFFFF00)) == htonl(0xE0000000))
+
+#define LOOPBACK(x)	is_ip4_loopback(x)
+#define MULTICAST(x)	is_ip4_multicast(x)
+#define LOCAL_MCAST(x)	is_ip4_local_multicast(x)
+#define BADCLASS(x)	is_ip4_badclass(x)
+#define ZERONET(x)	is_ip4_zeronet(x)
 
 #endif
 

Maybe I'm more used to hex, but I personally don't think those are more readable. It replaces 1-line macroes with 4-line functions, and I think more vgrepping to pick out the relevant constant data.

                                                +-DLS

The rfcs generally use decimal octets.
To me htonl(0xC0586300) isn't as readable as ip4_addr_octets(192,88,99,0)

Fred Templin has some patches that add several more macros to in.h. I just forwarded my patches to him too.

is_ip4_multicast seems a lot more readable to me than MULTICAST(x) I prefer to eliminate the current use of macros for ip address tests and also get no new macros added. The old macros are just for compatibility until the exis

http://marc.info/?l=linux-netdev&m=119490504022261&w=2

His patch adds:

+#define PRIVATE_10(x) (((x) & htonl(0xff000000)) == htonl(0x0A000000)) +#define LINKLOCAL_169(x) (((x) & htonl(0xffff0000)) == htonl(0xA9FE0000))
+#define PRIVATE_172(x) (((x) & htonl(0xfff00000)) == htonl(0xAC100000))
+#define TEST_192(x) (((x) & htonl(0xffffff00)) == htonl(0xC0000200))
+#define ANYCAST_6TO4(x) (((x) & htonl(0xffffff00)) == htonl(0xC0586300))
+#define PRIVATE_192(x) (((x) & htonl(0xffff0000)) == htonl(0xC0A80000))
+#define TEST_198(x) (((x) & htonl(0xfffe0000)) == htonl(0xC6120000))

cheers, Joe

Sorry, evolution died sending my mail and I didn't fully read the "recovered" mail before hitting send.

Here's a more readable one.

---------

The rfcs generally use decimal octets.

To me htonl(0xC0586300) isn't as readable as ip4_addr_octets(192,88,99,0) is_ip4_multicast(addr) more intelligible than MULTICAST(x).

I hope to eliminate the current use of macros for ip address tests and have no new macros added. The existing macros are just for compatibility until the current code uses are converted.

Fred Templin has some patches that add several more macros to in.h. I just forwarded my patches to him too.

http://marc.info/?l=linux-netdev&m=119490504022261&w=2

His patch adds:

+#define PRIVATE_10(x) (((x) & htonl(0xff000000)) == htonl(0x0A000000)) +#define LINKLOCAL_169(x) (((x) & htonl(0xffff0000)) == htonl(0xA9FE0000))
+#define PRIVATE_172(x) (((x) & htonl(0xfff00000)) == htonl(0xAC100000))
+#define TEST_192(x) (((x) & htonl(0xffffff00)) == htonl(0xC0000200))
+#define ANYCAST_6TO4(x) (((x) & htonl(0xffffff00)) == htonl(0xC0586300))
+#define PRIVATE_192(x) (((x) & htonl(0xffff0000)) == htonl(0xC0A80000))
+#define TEST_198(x) (((x) & htonl(0xfffe0000)) == htonl(0xC6120000))

cheers, Joe

From: David Stevens <[email protected]>
Date: Wed, 14 Nov 2007 08:53:13 -0800

Yes, the readability is agruable but I like the type checking.

I would also change the names, it's a better idea to prefix the names with a namespace for the stuff being operated on, therefore I'd prefer names like "ipv4_is_loopback()" etc.

I'm dropping these patches for now.

I used:

+static inline bool is_ip4_loopback(__be32 addr)

and converted the current uses in net of macros to use those functions directly. I'd prefer to drop the macros entirely, but there are uses in drivers/infiniband and drivers/parisc to convert too.

Is the use of "is_ip4_<level>" not "ipv4_is_<level>" your reason to drop the patches?

From: Joe Perches <[email protected]>
Date: Mon, 19 Nov 2007 21:59:58 -0800

Yes.