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 46d9c3a..2d7d6d4 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 d41d88b..379270f 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 5fea0ab..2012bc7 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);