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Message-Id: <1250548184.4488.6.camel@Joe-Laptop.home>
Date: Mon, 17 Aug 2009 15:29:44 -0700
From: Joe Perches <joe@...ches.com>
To: Jens Rosenboom <jens@...one.net>
Cc: David Miller <davem@...emloft.net>, chuck.lever@...cle.com,
brian.haley@...com, netdev@...r.kernel.org
Subject: [PATCH V2] lib/vsprintf.c: Add "%pI6c" - print pointer as
compressed ipv6 address
On Mon, 2009-08-17 at 17:18 +0200, Jens Rosenboom wrote:
> Two small optimizations:
Thanks. Another is to use the calculated "longest" to
increment i after the :: instead of counting 0's again.
Another possibility might be to make all the ip formatting
in vsprintf #ifdef'd on CONFIG_NET.
> Also I'm wondering whether it makes sense to pull the format code
> checking into all the sub-routines.
It isn't clear to me what you're asking for.
> It might be easier to maintain if it
> is all kept together in pointer().
Can you explain more thoroughly please?
If you mean not passing const char *fmt to the sub-routines,
I think not doing so makes it harder to maintain and extend.
I think it will be useful to extend the 'S' resource_string
capability to use fmt to allow specific bits to be selected
of the resource identifier to be printed.
See the idea in: http://lkml.org/lkml/2009/4/17/105
Here's the modified patch with your suggestions:
cheers,
Signed-off-by: Joe Perches <joe@...ches.com>
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 756ccaf..cb8a112 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -25,6 +25,7 @@
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/ioport.h>
+#include <net/addrconf.h>
#include <asm/page.h> /* for PAGE_SIZE */
#include <asm/div64.h>
@@ -630,60 +631,156 @@ static char *resource_string(char *buf, char *end, struct resource *res,
}
static char *mac_address_string(char *buf, char *end, u8 *addr,
- struct printf_spec spec)
+ struct printf_spec spec, const char *fmt)
{
- char mac_addr[6 * 3]; /* (6 * 2 hex digits), 5 colons and trailing zero */
+ char mac_addr[sizeof("xx:xx:xx:xx:xx:xx")];
char *p = mac_addr;
int i;
for (i = 0; i < 6; i++) {
p = pack_hex_byte(p, addr[i]);
- if (!(spec.flags & SPECIAL) && i != 5)
+ if (fmt[0] == 'M' && i != 5)
*p++ = ':';
}
*p = '\0';
- spec.flags &= ~SPECIAL;
return string(buf, end, mac_addr, spec);
}
-static char *ip6_addr_string(char *buf, char *end, u8 *addr,
- struct printf_spec spec)
+static char *ip4_string(char *p, const u8 *addr, bool leading_zeros)
+{
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ char temp[3]; /* hold each IP quad in reverse order */
+ int digits = put_dec_trunc(temp, addr[i]) - temp;
+ if (leading_zeros) {
+ if (digits < 3)
+ *p++ = '0';
+ if (digits < 2)
+ *p++ = '0';
+ }
+ /* reverse the digits in the quad */
+ while (digits--)
+ *p++ = temp[digits];
+ if (i < 3)
+ *p++ = '.';
+ }
+
+ *p = '\0';
+ return p;
+}
+
+static char *ip6_compressed_string(char *p, const struct in6_addr *addr)
{
- char ip6_addr[8 * 5]; /* (8 * 4 hex digits), 7 colons and trailing zero */
- char *p = ip6_addr;
int i;
+ int j;
+ int range;
+ unsigned char zerolength[8];
+ int longest = 1;
+ int colonpos = -1;
+ u16 word;
+ u8 hi;
+ u8 lo;
+ bool needcolon = false;
+ bool useIPv4 = ipv6_addr_v4mapped(addr) || ipv6_addr_is_isatap(addr);
+
+ memset(zerolength, 0, sizeof(zerolength));
+
+ if (useIPv4)
+ range = 6;
+ else
+ range = 8;
+
+ /* find position of longest 0 run */
+ for (i = 0; i < range; i++) {
+ for (j = i; j < range; j++) {
+ if (addr->s6_addr16[j] != 0)
+ break;
+ zerolength[i]++;
+ }
+ }
+ for (i = 0; i < range; i++) {
+ if (zerolength[i] > longest) {
+ longest = zerolength[i];
+ colonpos = i;
+ }
+ }
+
+ /* emit address */
+ for (i = 0; i < range; i++) {
+ if (i == colonpos) {
+ if (needcolon || i == 0)
+ *p++ = ':';
+ *p++ = ':';
+ needcolon = false;
+ i += longest - 1;
+ continue;
+ }
+ if (needcolon) {
+ *p++ = ':';
+ needcolon = false;
+ }
+ /* hex u16 without leading 0s */
+ word = ntohs(addr->s6_addr16[i]);
+ hi = word >> 8;
+ lo = word & 0xff;
+ if (hi) {
+ if (hi > 0x0f)
+ p = pack_hex_byte(p, hi);
+ else
+ *p++ = hex_asc_lo(hi);
+ }
+ if (hi || lo > 0x0f)
+ p = pack_hex_byte(p, lo);
+ else
+ *p++ = hex_asc_lo(lo);
+ needcolon = true;
+ }
+
+ if (useIPv4) {
+ if (needcolon)
+ *p++ = ':';
+ p = ip4_string(p, &addr->s6_addr[12], false);
+ }
+ *p = '\0';
+ return p;
+}
+
+static char *ip6_string(char *p, const struct in6_addr *addr, const char *fmt)
+{
+ 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 (!(spec.flags & SPECIAL) && i != 7)
+ p = pack_hex_byte(p, addr->s6_addr[2 * i]);
+ p = pack_hex_byte(p, addr->s6_addr[2 * i + 1]);
+ if (fmt[0] == 'I' && i != 7)
*p++ = ':';
}
+
*p = '\0';
- spec.flags &= ~SPECIAL;
+ return p;
+}
+
+static char *ip6_addr_string(char *buf, char *end, const u8 *addr,
+ struct printf_spec spec, const char *fmt)
+{
+ char ip6_addr[sizeof("xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255")];
+
+ if (fmt[0] == 'I' && fmt[2] == 'c')
+ ip6_compressed_string(ip6_addr, (const struct in6_addr *)addr);
+ else
+ ip6_string(ip6_addr, (const struct in6_addr *)addr, fmt);
return string(buf, end, ip6_addr, spec);
}
-static char *ip4_addr_string(char *buf, char *end, u8 *addr,
- struct printf_spec spec)
+static char *ip4_addr_string(char *buf, char *end, const u8 *addr,
+ struct printf_spec spec, const char *fmt)
{
- char ip4_addr[4 * 4]; /* (4 * 3 decimal digits), 3 dots and trailing zero */
- char temp[3]; /* hold each IP quad in reverse order */
- char *p = ip4_addr;
- int i, digits;
+ char ip4_addr[sizeof("255.255.255.255")];
- for (i = 0; i < 4; i++) {
- digits = put_dec_trunc(temp, addr[i]) - temp;
- /* reverse the digits in the quad */
- while (digits--)
- *p++ = temp[digits];
- if (i != 3)
- *p++ = '.';
- }
- *p = '\0';
- spec.flags &= ~SPECIAL;
+ ip4_string(ip4_addr, addr, fmt[0] == 'i');
return string(buf, end, ip4_addr, spec);
}
@@ -702,11 +799,15 @@ static char *ip4_addr_string(char *buf, char *end, u8 *addr,
* 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
- * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way (dot-separated
- * decimal for v4 and colon separated network-order 16 bit hex for v6)
- * - 'i' [46] for 'raw' IPv4/IPv6 addresses, IPv6 omits the colons, IPv4 is
- * currently the same
- *
+ * - 'm' For a 6-byte MAC address, it prints the hex address without colons
+ * - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
+ * IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
+ * IPv6 uses colon separated network-order 16 bit hex with leading 0's
+ * - 'i' [46] for 'raw' IPv4/IPv6 addresses
+ * IPv6 omits the colons (01020304...0f)
+ * IPv4 uses dot-separated decimal with leading 0's (010.123.045.006)
+ * - 'I6c' for IPv6 addresses printed as specified by
+ * http://www.ietf.org/id/draft-kawamura-ipv6-text-representation-03.txt
* Note: The difference between 'S' and 'F' is that on ia64 and ppc64
* function pointers are really function descriptors, which contain a
* pointer to the real address.
@@ -726,20 +827,24 @@ static char *pointer(const char *fmt, char *buf, char *end, void *ptr,
return symbol_string(buf, end, ptr, spec, *fmt);
case 'R':
return resource_string(buf, end, ptr, spec);
- case 'm':
- spec.flags |= SPECIAL;
- /* Fallthrough */
- case 'M':
- return mac_address_string(buf, end, ptr, spec);
- case 'i':
- spec.flags |= SPECIAL;
- /* Fallthrough */
- case 'I':
- if (fmt[1] == '6')
- return ip6_addr_string(buf, end, ptr, spec);
- if (fmt[1] == '4')
- return ip4_addr_string(buf, end, ptr, spec);
- spec.flags &= ~SPECIAL;
+ case 'M': /* Colon separated: 00:01:02:03:04:05 */
+ case 'm': /* Contiguous: 000102030405 */
+ return mac_address_string(buf, end, ptr, spec, fmt);
+ case 'I': /* Formatted IP supported
+ * 4: 1.2.3.4
+ * 6: 0001:0203:...:0708
+ * 6c: 1::708 or 1::1.2.3.4
+ */
+ case 'i': /* Contiguous:
+ * 4: 001.002.003.004
+ * 6: 000102...0f
+ */
+ switch (fmt[1]) {
+ case '6':
+ return ip6_addr_string(buf, end, ptr, spec, fmt);
+ case '4':
+ return ip4_addr_string(buf, end, ptr, spec, fmt);
+ }
break;
}
spec.flags |= SMALL;
cheers, Joe
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