iptunnel: simplify parsing TTL, allow 'hlim' as identifier

Instead of parsing an unsigned integer and checking boundaries, simply
parse u8. This and the added ttl alias 'hlim' provide consistency with
ip6tunnel.
Signed-off-by: Phil Sutter <phil@nwl.cc>

ip/iptunnel.c

@@ -141,14 +141,13 @@ static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
 			NEXT_ARG();
 			strncpy(medium, *argv, IFNAMSIZ-1);
 		} else if (strcmp(*argv, "ttl") == 0 ||
-			   strcmp(*argv, "hoplimit") == 0) {
-			unsigned uval;
+			   strcmp(*argv, "hoplimit") == 0 ||
+			   strcmp(*argv, "hlim") == 0) {
+			__u8 uval;
 			NEXT_ARG();
 			if (strcmp(*argv, "inherit") != 0) {
-				if (get_unsigned(&uval, *argv, 0))
+				if (get_u8(&uval, *argv, 0))
 					invarg("invalid TTL\n", *argv);
-				if (uval > 255)
-					invarg("TTL must be <=255\n", *argv);
 				p->iph.ttl = uval;
 			}
 		} else if (strcmp(*argv, "tos") == 0 ||