str: Add str2mac helper function

Add function to convert a string in the format xx:xx:xx:xx:xx:xx to a
MAC address byte array.

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
[tk: Add len parameter and error out on too short buffers]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

2 files changed, 32 insertions, 0 deletions

diff --git a/str.c b/str.c
index e4d8722..cfee03f 100644
--- a/str.c
+++ b/str.c
@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdarg.h>
+#include <arpa/inet.h>
 
 #include "str.h"
 #include "die.h"
@@ -129,3 +130,31 @@ void argv_free(char **argv)
 
 	free(tmp);
 }
+
+int str2mac(const char *str, uint8_t *mac, size_t len)
+{
+	int i, count;
+	unsigned int tmp[6];
+
+	if (!str)
+	       return -EINVAL;
+	if (len < 6)
+		return -ENOSPC;
+
+	count = sscanf(str, "%02X:%02X:%02X:%02X:%02X:%02X",
+			&tmp[0], &tmp[1], &tmp[2], &tmp[3], &tmp[4], &tmp[5]);
+
+	if (errno || count != 6)
+		count = sscanf(str, "%02x:%02x:%02x:%02x:%02x:%02x",
+			&tmp[0], &tmp[1], &tmp[2], &tmp[3], &tmp[4], &tmp[5]);
+
+	if (count != 6)
+		return -EINVAL;
+	if (errno)
+		return -errno;
+
+	for (i = 0; i < 6; i++)
+		mac[i] = (uint8_t)tmp[i];
+
+	return 0;
+}
diff --git a/str.h b/str.h
index 3ffb2b9..7879af6 100644
--- a/str.h
+++ b/str.h
@@ -1,6 +1,8 @@
 #ifndef STR_H
 #define STR_H
 
+#include <stdlib.h>
+
 #include "built_in.h"
 
 extern size_t strlcpy(char *dest, const char *src, size_t size);
@@ -11,5 +13,6 @@ extern noinline void *xmemset(void *s, int c, size_t n);
 extern char *argv2str(int startind, int argc, char **argv);
 extern char **argv_insert(char **argv, size_t *count, const char *str);
 extern void argv_free(char **argv);
+extern int str2mac(const char *str, uint8_t *mac, size_t len);
 
 #endif /* STR_H */