net: add mac_pton() for parsing MAC address

mac_pton() parses MAC address in form XX:XX:XX:XX:XX:XX and only in that form.

mac_pton() doesn't dirty result until it's sure string representation is valid.

mac_pton() doesn't care about characters _after_ last octet,
it's up to caller to deal with it.

mac_pton() diverges from 0/-E return value convention.
Target usage:

	if (!mac_pton(str, whatever->mac))
		return -EINVAL;
	/* ->mac being u8 [ETH_ALEN] is filled at this point. */
	/* optionally check str[3 * ETH_ALEN - 1] for termination */

Use mac_pton() in pktgen and netconsole for start.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 16 deletions

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 62fdbaa1fb60..a83e101440fd 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -429,8 +429,6 @@ static ssize_t store_remote_mac(struct netconsole_target *nt,
                                 size_t count)
 {
         u8 remote_mac[ETH_ALEN];
-        char *p = (char *) buf;
-        int i;
 
         if (nt->enabled) {
                 printk(KERN_ERR "netconsole: target (%s) is enabled, "
@@ -439,23 +437,13 @@ static ssize_t store_remote_mac(struct netconsole_target *nt,
                 return -EINVAL;
         }
 
-        for (i = 0; i < ETH_ALEN - 1; i++) {
-                remote_mac[i] = simple_strtoul(p, &p, 16);
-                if (*p != ':')
-                        goto invalid;
-                p++;
-        }
-        remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
-        if (*p && (*p != '\n'))
-                goto invalid;
-
+        if (!mac_pton(buf, remote_mac))
+                return -EINVAL;
+        if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
+                return -EINVAL;
         memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
 
         return strnlen(buf, count);
-
-invalid:
-        printk(KERN_ERR "netconsole: invalid input\n");
-        return -EINVAL;
 }
 
 /*