classid auto generation if provided tc name does not exist

Manually editing etc/libnl/classid before adding tc objects is a pain.
This patch adds code to attempt auto generating a unique tc id which
will then be assigned to the provided name and added to the classid
file.

This will make the following commands work with prior definitions of
the names "top" and "test"
	sudo sbin/nl-qdisc-add --dev eth0 --parent root --id top htb
	sudo sbin/nl-class-add --dev eth0 --parent top --id test htb --rate 100mbit

It will generate the following ids automatically:
4001:			top
4001:1			test

1 files changed, 12 insertions, 5 deletions

diff --git a/src/lib/tc.c b/src/lib/tc.c
index 5f39498..72407cf 100644
--- a/src/lib/tc.c
+++ b/src/lib/tc.c
@@ -42,14 +42,21 @@ void nl_cli_tc_parse_parent(struct rtnl_tc *tc, char *arg)
 	rtnl_tc_set_parent(tc, parent);
 }
 
-void nl_cli_tc_parse_handle(struct rtnl_tc *tc, char *arg)
+void nl_cli_tc_parse_handle(struct rtnl_tc *tc, char *arg, int create)
 {
-	uint32_t handle;
+	uint32_t handle, parent;
 	int err;
 
-	if ((err = rtnl_tc_str2handle(arg, &handle)) < 0)
-		nl_cli_fatal(err, "Unable to parse handle \"%s\": %s",
-		      arg, nl_geterror(err));
+	parent = rtnl_tc_get_parent(tc);
+
+	if ((err = rtnl_tc_str2handle(arg, &handle)) < 0) {
+		if (err == -NLE_OBJ_NOTFOUND && create)
+			err = rtnl_classid_generate(arg, &handle, parent);
+
+		if (err < 0)
+			nl_cli_fatal(err, "Unable to parse handle \"%s\": %s",
+				     arg, nl_geterror(err));
+	}
 
 	rtnl_tc_set_handle(tc, handle);
 }