lib/vsprintf.c: Add "%pI6c" - print pointer as compressed ipv6 address

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Jens Rosenboom <jens@mcbone.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 152 insertions, 47 deletions

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 756ccafa9cec..cb8a112030bb 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;