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>

3 files changed, 33 insertions, 70 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 46d9c3a4de2f..2d7d6d473781 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -698,32 +698,8 @@ int netpoll_parse_options(struct netpoll *np, char *opt)
 
         if (*cur != 0) {
                 /* MAC address */
-                if ((delim = strchr(cur, ':')) == NULL)
+                if (!mac_pton(cur, np->remote_mac))
                         goto parse_failed;
-                *delim = 0;
-                np->remote_mac[0] = simple_strtol(cur, NULL, 16);
-                cur = delim + 1;
-                if ((delim = strchr(cur, ':')) == NULL)
-                        goto parse_failed;
-                *delim = 0;
-                np->remote_mac[1] = simple_strtol(cur, NULL, 16);
-                cur = delim + 1;
-                if ((delim = strchr(cur, ':')) == NULL)
-                        goto parse_failed;
-                *delim = 0;
-                np->remote_mac[2] = simple_strtol(cur, NULL, 16);
-                cur = delim + 1;
-                if ((delim = strchr(cur, ':')) == NULL)
-                        goto parse_failed;
-                *delim = 0;
-                np->remote_mac[3] = simple_strtol(cur, NULL, 16);
-                cur = delim + 1;
-                if ((delim = strchr(cur, ':')) == NULL)
-                        goto parse_failed;
-                *delim = 0;
-                np->remote_mac[4] = simple_strtol(cur, NULL, 16);
-                cur = delim + 1;
-                np->remote_mac[5] = simple_strtol(cur, NULL, 16);
         }
 
         netpoll_print_options(np);
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index d41d88b53e18..379270f14771 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -1420,11 +1420,6 @@ static ssize_t pktgen_if_write(struct file *file,
                 return count;
         }
         if (!strcmp(name, "dst_mac")) {
-                char *v = valstr;
-                unsigned char old_dmac[ETH_ALEN];
-                unsigned char *m = pkt_dev->dst_mac;
-                memcpy(old_dmac, pkt_dev->dst_mac, ETH_ALEN);
-
                 len = strn_len(&user_buffer[i], sizeof(valstr) - 1);
                 if (len < 0)
                         return len;
@@ -1432,35 +1427,16 @@ static ssize_t pktgen_if_write(struct file *file,
                 memset(valstr, 0, sizeof(valstr));
                 if (copy_from_user(valstr, &user_buffer[i], len))
                         return -EFAULT;
-                i += len;
-
-                for (*m = 0; *v && m < pkt_dev->dst_mac + 6; v++) {
-                        int value;
-
-                        value = hex_to_bin(*v);
-                        if (value >= 0)
-                                *m = *m * 16 + value;
-
-                        if (*v == ':') {
-                                m++;
-                                *m = 0;
-                        }
-                }
 
+                if (!mac_pton(valstr, pkt_dev->dst_mac))
+                        return -EINVAL;
                 /* Set up Dest MAC */
-                if (compare_ether_addr(old_dmac, pkt_dev->dst_mac))
-                        memcpy(&(pkt_dev->hh[0]), pkt_dev->dst_mac, ETH_ALEN);
+                memcpy(&pkt_dev->hh[0], pkt_dev->dst_mac, ETH_ALEN);
 
-                sprintf(pg_result, "OK: dstmac");
+                sprintf(pg_result, "OK: dstmac %pM", pkt_dev->dst_mac);
                 return count;
         }
         if (!strcmp(name, "src_mac")) {
-                char *v = valstr;
-                unsigned char old_smac[ETH_ALEN];
-                unsigned char *m = pkt_dev->src_mac;
-
-                memcpy(old_smac, pkt_dev->src_mac, ETH_ALEN);
-
                 len = strn_len(&user_buffer[i], sizeof(valstr) - 1);
                 if (len < 0)
                         return len;
@@ -1468,26 +1444,13 @@ static ssize_t pktgen_if_write(struct file *file,
                 memset(valstr, 0, sizeof(valstr));
                 if (copy_from_user(valstr, &user_buffer[i], len))
                         return -EFAULT;
-                i += len;
-
-                for (*m = 0; *v && m < pkt_dev->src_mac + 6; v++) {
-                        int value;
-
-                        value = hex_to_bin(*v);
-                        if (value >= 0)
-                                *m = *m * 16 + value;
-
-                        if (*v == ':') {
-                                m++;
-                                *m = 0;
-                        }
-                }
 
+                if (!mac_pton(valstr, pkt_dev->src_mac))
+                        return -EINVAL;
                 /* Set up Src MAC */
-                if (compare_ether_addr(old_smac, pkt_dev->src_mac))
-                        memcpy(&(pkt_dev->hh[6]), pkt_dev->src_mac, ETH_ALEN);
+                memcpy(&pkt_dev->hh[6], pkt_dev->src_mac, ETH_ALEN);
 
-                sprintf(pg_result, "OK: srcmac");
+                sprintf(pg_result, "OK: srcmac %pM", pkt_dev->src_mac);
                 return count;
         }
 
diff --git a/net/core/utils.c b/net/core/utils.c
index 5fea0ab21902..2012bc797f9c 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -296,3 +296,27 @@ void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
                                 csum_unfold(*sum)));
 }
 EXPORT_SYMBOL(inet_proto_csum_replace4);
+
+int mac_pton(const char *s, u8 *mac)
+{
+        int i;
+
+        /* XX:XX:XX:XX:XX:XX */
+        if (strlen(s) < 3 * ETH_ALEN - 1)
+                return 0;
+
+        /* Don't dirty result unless string is valid MAC. */
+        for (i = 0; i < ETH_ALEN; i++) {
+                if (!strchr("0123456789abcdefABCDEF", s[i * 3]))
+                        return 0;
+                if (!strchr("0123456789abcdefABCDEF", s[i * 3 + 1]))
+                        return 0;
+                if (i != ETH_ALEN - 1 && s[i * 3 + 2] != ':')
+                        return 0;
+        }
+        for (i = 0; i < ETH_ALEN; i++) {
+                mac[i] = (hex_to_bin(s[i * 3]) << 4) | hex_to_bin(s[i * 3 + 1]);
+        }
+        return 1;
+}
+EXPORT_SYMBOL(mac_pton);