Interface names can be more than 7 chars long.

Patch by Aleksey Fedoseev.

--- vnstat-1.4/src/proc.c
+++ vnstat-1.4/src/proc.c
@@ -64,6 +64,7 @@
 void parseproc(int newdb)
 {
 	char temp[64];
+	char* colon_pos;
 	uint64_t rx, tx, rxchange=0, txchange=0, btime;   /* rxchange = rx change in MB */
 	uint64_t krxchange=0, ktxchange=0;                /* krxchange = rx change in kB */
 	time_t current;
@@ -86,12 +87,22 @@

 	current=time(NULL);

-	/* get rx from procline, easy since it's always procline+7 */
+	/* get rx position, then get it from procline */
+
+	colon_pos = strchr(procline, ':');
+	if (colon_pos == NULL) {
+		if (debug) {
+			printf("Bad /proc/net/dev string");
+		}
+		return;
+	}
+
+	colon_pos++;

 #ifdef BLIMIT
-	rx=strtoull(procline+7, (char **)NULL, 0);
+	rx=strtoull(colon_pos,  (char **)NULL, 0);
 #else
-	rx=strtoul(procline+7, (char **)NULL, 0);
+	rx=strtoul(colon_pos,  (char **)NULL, 0);
 #endif
 
 	if (newdb!=1) {
@@ -116,7 +127,7 @@
 
 
 	/* get tx from procline, ugly hack */
-	sscanf(procline+7,"%s %s %s %s %s %s %s %s %s",temp,temp,temp,temp,temp,temp,temp,temp,temp);
+	sscanf(colon_pos, "%s %s %s %s %s %s %s %s %s",temp,temp,temp,temp,temp,temp,temp,temp,temp);
 
 #ifdef BLIMIT
 	tx=strtoull(temp, (char **)NULL, 0);