Merge pull request #5146 from ssahani/ifname-alias

networkd: Allow ':' in label

This reverts a341dfe563 and takes a slightly different approach: anything is
allowed in network interface labels, but network interface names are verified
as before (i.e. amongst other things, no colons are allowed there).

src/basic/socket-util.c

@@ -887,7 +887,7 @@ bool ifname_valid(const char *p) {
                 if ((unsigned char) *p <= 32U)
                         return false;
 
-                if (*p == '/')
+                if (*p == ':' || *p == '/')
                         return false;
 
                 numeric = numeric && (*p >= '0' && *p <= '9');