[RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[Harvey Harrison]

Add format specifiers for printing out colon-separated bytes:

MAC addresses (%pM):
xx:xx:xx:xx:xx:xx

IPv4 addresses (%p4):
xx:xx:xx:xx

IPv6 addresses (%p6):
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

%#pM, %#p4, %#p6 are also supported and print without the colon
separators.

[Based on Johannes Berg's initial patch]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
This one without the embarrassing index typos in ip6_address and mac_address.

 lib/vsprintf.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 64 insertions(+), 0 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a013bbc..eec3879 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -581,6 +581,58 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie
 	return string(buf, end, sym, field_width, precision, flags);
 }
 
+static char *ip4_address(char *buf, char *end, u8 *addr, int field_width,
+			 int precision, int flags)
+{
+	char ip4_addr[4 * 3]; /* (4 * 2 hex digits), 3 colons and trailing zero */
+	char *p = ip4_addr;
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		p = pack_hex_byte(p, addr[i]);
+		if (!(flags & SPECIAL) && i != 3)
+			*p++ = ':';
+	}
+	*p = '\0';
+
+	return string(buf, end, ip4_addr, field_width, precision, flags & ~SPECIAL);
+}
+
+static char *ip6_address(char *buf, char *end, u8 *addr, int field_width,
+			 int precision, int flags)
+{
+	char ip6_addr[8 * 5]; /* (8 * 4 hex digits), 7 colons and trailing zero */
+	char *p = ip6_addr;
+	int i;
+
+	for (i = 0; i < 8; i++) {
+		p = pack_hex_byte(p, addr[2 * i]);
+		p = pack_hex_byte(p, addr[2 * i + 1]);
+		if (!(flags & SPECIAL) && i != 7)
+			*p++ = ':';
+	}
+	*p = '\0';
+
+	return string(buf, end, ip6_addr, field_width, precision, flags & ~SPECIAL);
+}
+
+static char *mac_address(char *buf, char *end, u8 *addr, int field_width,
+			 int precision, int flags)
+{
+	char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
+	char *p = mac_addr;
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		p = pack_hex_byte(p, addr[i]);
+		if (!(flags & SPECIAL) && i != 5)
+			*p++ = ':';
+	}
+	*p = '\0';
+
+	return string(buf, end, mac_addr, field_width, precision, flags & ~SPECIAL);
+}
+
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
@@ -592,6 +644,12 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie
  * - 'S' For symbolic direct pointers
  * - 'R' For a struct resource pointer, it prints the range of
  *       addresses (not the name nor the flags)
+ * - 'M' For a 6-byte MAC address, it prints the address in the
+ *       usual colon-separated hex notation
+ * - '4' For a 4-byte IPv4 address, it prints the address in the
+ *       usual colon-separated hex notation
+ * - 'M' For a 16-byte IPv6 address, it prints the address in colon separated
+ *       big-endian 16 bit hex notation
  *
  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
  * function pointers are really function descriptors, which contain a
@@ -607,6 +665,12 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field
 		return symbol_string(buf, end, ptr, field_width, precision, flags);
 	case 'R':
 		return resource_string(buf, end, ptr, field_width, precision, flags);
+	case 'M':
+		return mac_address(buf, end, ptr, field_width, precision, flags);
+	case '4':
+		return ip4_address(buf, end, ptr, field_width, precision, flags);
+	case '6':
+		return ip6_address(buf, end, ptr, field_width, precision, flags);
 	}
 	flags |= SMALL;
 	if (field_width == -1) {
-- 
1.6.0.3.729.g6ea410

Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[Frans Pop]

Harvey Harrison wrote:
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index a013bbc..eec3879 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -592,6 +644,12 @@ static char *resource_string(char *buf, char *end,
> struct resource *res, int fie
>   * - 'S' For symbolic direct pointers
>   * - 'R' For a struct resource pointer, it prints the range of
>   *       addresses (not the name nor the flags)
> + * - 'M' For a 6-byte MAC address, it prints the address in the
> + *       usual colon-separated hex notation
> + * - '4' For a 4-byte IPv4 address, it prints the address in the
> + *       usual colon-separated hex notation
> + * - 'M' For a 16-byte IPv6 address, it prints the address in colon separated
> + *       big-endian 16 bit hex notation

Shouldn't that last one be '6' instead of 'M'?

Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[H. Peter Anvin]

Frans Pop wrote:
>> + * - '4' For a 4-byte IPv4 address, it prints the address in the
>> + *       usual colon-separated hex notation

Since when are IPv4 addresses "usually" printed in colon-separated hex?

	-hpa

Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[Johannes Berg]

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On Sun, 2008-10-26 at 17:31 -0700, Harvey Harrison wrote:
> Add format specifiers for printing out colon-separated bytes:
> 
> MAC addresses (%pM):
> xx:xx:xx:xx:xx:xx
> 
> IPv4 addresses (%p4):
> xx:xx:xx:xx

As hpa points out, the usual notation would be %d.%d.%d.%d :)

> %#pM, %#p4, %#p6 are also supported and print without the colon
> separators.

The # for ipv4 we might use for cpu-endian rather than network-endian
maybe?

Also can you keep mac/ip address patches split up so we can use my
version of the mac address patch (it's already well-tested)?

johannes

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Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[Harvey Harrison]

On Mon, 2008-10-27 at 07:59 +0100, Johannes Berg wrote:

> Also can you keep mac/ip address patches split up so we can use my
> version of the mac address patch (it's already well-tested)?
> 

Sure.  I'll build on top.

Harvey

Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[David Miller]

From: Harvey Harrison <harvey.harrison@gmail.com>
Date: Mon, 27 Oct 2008 09:28:24 -0700

> On Mon, 2008-10-27 at 07:59 +0100, Johannes Berg wrote:
> 
> > Also can you keep mac/ip address patches split up so we can use my
> > version of the mac address patch (it's already well-tested)?
> > 
> 
> Sure.  I'll build on top.

So I'll wait for Harvey's "v3" of this patch, and once I have that in
the net-next-2.6 tree I'll start adding Johannes's conversions on top.

Re: [RFC PATCHv2] printk: add the %pM, %p4, %p6 format specifiers

[Johannes Berg]

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On Mon, 2008-10-27 at 12:38 -0700, David Miller wrote:
> From: Harvey Harrison <harvey.harrison@gmail.com>
> Date: Mon, 27 Oct 2008 09:28:24 -0700
> 
> > On Mon, 2008-10-27 at 07:59 +0100, Johannes Berg wrote:
> > 
> > > Also can you keep mac/ip address patches split up so we can use my
> > > version of the mac address patch (it's already well-tested)?
> > > 
> > 
> > Sure.  I'll build on top.
> 
> So I'll wait for Harvey's "v3" of this patch, and once I have that in
> the net-next-2.6 tree I'll start adding Johannes's conversions on top.

Ok, fine with me too. Harvey, can you sort out the ip4 issue and then
send with %pM included?

johannes

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[RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Harvey Harrison]

Add format specifiers for printing out six colon-separated bytes:

MAC addresses (%pM):
xx:xx:xx:xx:xx:xx

%#pM is also supported and omits the colon separators.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
Dave, this passes testing here, but I was wondering if perhaps it would be
better to allow a length to be specified as well, which would allow:

%pM6 for mac addresses, etc as there seem a lot of places in kernel that
print out a list of colon separated bytes of various lengths.

But if that was added, it may be more natural to call it 
%pB (bytes)
%pW (words)

Then mac addresses would be %pB6
IPv6 addresses would be %pW8 (8 words)

It would be trivial to add, but maybe I'm overthinking this.  In any event,
this patch only adds %pM for mac addresses.

 lib/vsprintf.c |   21 +++++++++++++++++++++
 1 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a013bbc..2025305 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -581,6 +581,23 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie
 	return string(buf, end, sym, field_width, precision, flags);
 }
 
+static char *mac_address(char *buf, char *end, u8 *addr, int field_width,
+			 int precision, int flags)
+{
+	char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
+	char *p = mac_addr;
+	int i;
+
+	for (i = 0; i < 6; i++) {
+		p = pack_hex_byte(p, addr[i]);
+		if (!(flags & SPECIAL) && i != 5)
+			*p++ = ':';
+	}
+	*p = '\0';
+
+	return string(buf, end, mac_addr, field_width, precision, flags & ~SPECIAL);
+}
+
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
@@ -592,6 +609,8 @@ static char *resource_string(char *buf, char *end, struct resource *res, int fie
  * - 'S' For symbolic direct pointers
  * - 'R' For a struct resource pointer, it prints the range of
  *       addresses (not the name nor the flags)
+ * - 'M' For a 6-byte MAC address, it prints the address in the
+ *       usual colon-separated hex notation
  *
  * Note: The difference between 'S' and 'F' is that on ia64 and ppc64
  * function pointers are really function descriptors, which contain a
@@ -607,6 +626,8 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field
 		return symbol_string(buf, end, ptr, field_width, precision, flags);
 	case 'R':
 		return resource_string(buf, end, ptr, field_width, precision, flags);
+	case 'M':
+		return mac_address(buf, end, ptr, field_width, precision, flags);
 	}
 	flags |= SMALL;
 	if (field_width == -1) {
-- 
1.6.0.3.729.g6ea410

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Joe Perches]

On Mon, 2008-10-27 at 12:59 -0700, Harvey Harrison wrote:

The changes to use %p4 aren't too bad.
I did that last year using a similar style
to print_mac.  80 or so files.
http://repo.or.cz/w/linux-2.6/trivial-mods.git?a=shortlog;h=refs/heads/print_ipv4
ipv6 was 30 or so files
http://repo.or.cz/w/linux-2.6/trivial-mods.git?a=shortlog;h=refs/heads/print_ipv6

> I was wondering if perhaps it would be
> better to allow a length to be specified as well, which would allow:
[]
> But if that was added, it may be more natural to call it 
> %pB (bytes)
> %pW (words)

I think length would not be good addition.
print_dump_hex already does a fine job.
There are also BE/LE expectation problems with pW.

The %p6 pointer should be in6_addr *
The %p4 pointer should be __be32 *.
Printing an ipv4 address should use %u.%u.%u.%u

I've been doodling with sparse to check
calls with __attribute__(format(printf
parsing the format strings for %p<FOO>
and match the argument types.

I'll post it if anything comes of it.

> +static char *mac_address(char *buf, char *end, u8 *addr, int field_width,
> +			 int precision, int flags)
> +{

mac_address_string please.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[David Miller]

From: Joe Perches <joe@perches.com>
Date: Mon, 27 Oct 2008 14:55:15 -0700

> On Mon, 2008-10-27 at 12:59 -0700, Harvey Harrison wrote:
> 
> > +static char *mac_address(char *buf, char *end, u8 *addr, int field_width,
> > +			 int precision, int flags)
> > +{
> 
> mac_address_string please.

I'll make this change when I apply Harvey's patch.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[David Miller]

From: Harvey Harrison <harvey.harrison@gmail.com>
Date: Mon, 27 Oct 2008 12:59:02 -0700

> Add format specifiers for printing out six colon-separated bytes:
> 
> MAC addresses (%pM):
> xx:xx:xx:xx:xx:xx
> 
> %#pM is also supported and omits the colon separators.
> 
> Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>

Applied, thanks.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Harvey Harrison]

On Mon, 2008-10-27 at 15:47 -0700, David Miller wrote:
> From: Harvey Harrison <harvey.harrison@gmail.com>
> Date: Mon, 27 Oct 2008 12:59:02 -0700
> 
> > Add format specifiers for printing out six colon-separated bytes:
> > 
> > MAC addresses (%pM):
> > xx:xx:xx:xx:xx:xx
> > 
> > %#pM is also supported and omits the colon separators.
> > 
> > Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> 
> Applied, thanks.

Did you happen to have a preference with regard to the specifier for
IPv6 addresses:

I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
%#pI6 for NIP6_SEQFMT.

On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
the periods isn't useful?

What do you think of that?

Harvey

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Alexey Dobriyan]

On Mon, Oct 27, 2008 at 04:14:14PM -0700, Harvey Harrison wrote:
> On Mon, 2008-10-27 at 15:47 -0700, David Miller wrote:
> > From: Harvey Harrison <harvey.harrison@gmail.com>
> > Date: Mon, 27 Oct 2008 12:59:02 -0700
> > 
> > > Add format specifiers for printing out six colon-separated bytes:
> > > 
> > > MAC addresses (%pM):
> > > xx:xx:xx:xx:xx:xx
> > > 
> > > %#pM is also supported and omits the colon separators.
> > > 
> > > Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
> > 
> > Applied, thanks.
> 
> Did you happen to have a preference with regard to the specifier for
> IPv6 addresses:
> 
> I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
> %#pI6 for NIP6_SEQFMT.
> 
> On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
> and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
> the periods isn't useful?

%#pI4 is horrible and %p4 and %p6 were cool.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Joe Perches]

On Mon, 2008-10-27 at 16:14 -0700, Harvey Harrison wrote:
> I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
> %#pI6 for NIP6_SEQFMT.
> 
> On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
> and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
> the periods isn't useful?

HIPQUAD is horrible and should disappear.
Just use htonl first.

I think just %p4 %p6 %#p6 for the NIP6_SEQFMT uses.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Johannes Berg]

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On Mon, 2008-10-27 at 16:48 -0700, Joe Perches wrote:
> On Mon, 2008-10-27 at 16:14 -0700, Harvey Harrison wrote:
> > I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
> > %#pI6 for NIP6_SEQFMT.
> > 
> > On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
> > and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
> > the periods isn't useful?
> 
> HIPQUAD is horrible and should disappear.
> Just use htonl first.

But you can't really say

printk("... %p4 ...", &htonl(host_ip4));

can you? I suppose the compiler would actually create a variable for
that?

johannes

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Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[David Miller]

From: Harvey Harrison <harvey.harrison@gmail.com>
Date: Mon, 27 Oct 2008 16:14:14 -0700

> Did you happen to have a preference with regard to the specifier for
> IPv6 addresses:
> 
> I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
> %#pI6 for NIP6_SEQFMT.
> 
> On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
> and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
> the periods isn't useful?
> 
> What do you think of that?

I'm ok with the '#' modifier but remind me again what's wrong with
using plain %p4 and %p6?

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Harvey Harrison]

On Mon, 2008-10-27 at 16:55 -0700, David Miller wrote:
> From: Harvey Harrison <harvey.harrison@gmail.com>
> Date: Mon, 27 Oct 2008 16:14:14 -0700
> 
> > Did you happen to have a preference with regard to the specifier for
> > IPv6 addresses:
> > 
> > I was thinking of using %pI6 to replace NIP6() and NIP6_FMT and using
> > %#pI6 for NIP6_SEQFMT.
> > 
> > On the IPv4 side, maybe use %pI4 for network endian NIPQUAD() and NIPQUAD_FMT
> > and then %#pI4 for host-endian HIQUAD(), as displaying the IPv4 address without
> > the periods isn't useful?
> > 
> > What do you think of that?
> 
> I'm ok with the '#' modifier but remind me again what's wrong with
> using plain %p4 and %p6?

Nothing at all, just wanted to know what color bikeshed you wanted.

I'll go with %p4 %p6.

Harvey

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Joe Perches]

On Mon, 2008-10-27 at 17:05 -0700, Harvey Harrison wrote:
> On Mon, 2008-10-27 at 16:55 -0700, David Miller wrote:
> > I'm ok with the '#' modifier but remind me again what's wrong with
> > using plain %p4 and %p6?
> Nothing at all, just wanted to know what color bikeshed you wanted.
> I'll go with %p4 %p6.

Just an FYI for v6 addresses:

There are a few uses of ipv6 address as "%08X%08X%08X%08X" 
Pavel Emelyanov tried to isolate them with a suggested patch:

http://www.mail-archive.com/netdev@vger.kernel.org/msg51655.html

These addresses are not shown in network order, but are
printed backwards in host order. Oops.  Apparently it's
too late to fix them.

Re: [RFC PATCHv3] printk: add %pM format specifier for MAC addresses

[Johannes Berg]

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On Mon, 2008-10-27 at 17:22 -0700, Joe Perches wrote:
> On Mon, 2008-10-27 at 17:05 -0700, Harvey Harrison wrote:
> > On Mon, 2008-10-27 at 16:55 -0700, David Miller wrote:
> > > I'm ok with the '#' modifier but remind me again what's wrong with
> > > using plain %p4 and %p6?
> > Nothing at all, just wanted to know what color bikeshed you wanted.
> > I'll go with %p4 %p6.
> 
> Just an FYI for v6 addresses:
> 
> There are a few uses of ipv6 address as "%08X%08X%08X%08X" 
> Pavel Emelyanov tried to isolate them with a suggested patch:
> 
> http://www.mail-archive.com/netdev@vger.kernel.org/msg51655.html
> 
> These addresses are not shown in network order, but are
> printed backwards in host order. Oops.  Apparently it's
> too late to fix them.

So that code we don't touch here at all.

johannes

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