nl-qdisc-add tool

Adds a cli based tool to add/update/replace qdiscs. This tool requires
each qdisc to be supported via a dynamic loadable module in
pkglibdir/cli/qdisc/$name.so.

So far HTB and blackhole have been implemented.

Syntax:
nl-qdisc-add --dev eth2 --parent root --id 1: htb --r2q=5
nl-qdisc-add --update-only --dev eth2 --id 1: htb --r2q=10

2 files changed, 92 insertions, 3 deletions

diff --git a/src/lib/qdisc.c b/src/lib/qdisc.c
index bc7ff92..52b7a6a 100644
--- a/src/lib/qdisc.c
+++ b/src/lib/qdisc.c
@@ -6,13 +6,12 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2008-2009 Thomas Graf <tgraf@suug.ch>
+ * Copyright (c) 2008-2010 Thomas Graf <tgraf@suug.ch>
  */
 
 /**
  * @ingroup cli
  * @defgroup cli_qdisc Queueing Disciplines
- *
  * @{
  */
 
@@ -69,4 +68,58 @@ void nl_cli_qdisc_parse_kind(struct rtnl_qdisc *qdisc, char *arg)
 	rtnl_qdisc_set_kind(qdisc, arg);
 }
 
+static NL_LIST_HEAD(qdisc_modules);
+
+struct nl_cli_qdisc_module *__nl_cli_qdisc_lookup(struct rtnl_qdisc_ops *ops)
+{
+	struct nl_cli_qdisc_module *qm;
+
+	nl_list_for_each_entry(qm, &qdisc_modules, qm_list)
+		if (qm->qm_ops == ops)
+			return qm;
+
+	return NULL;
+}
+
+struct nl_cli_qdisc_module *nl_cli_qdisc_lookup(struct rtnl_qdisc_ops *ops)
+{
+	struct nl_cli_qdisc_module *qm;
+
+	if ((qm = __nl_cli_qdisc_lookup(ops)))
+		return qm;
+
+	nl_cli_load_module("cli/qdisc", ops->qo_kind);
+
+	if (!(qm = __nl_cli_qdisc_lookup(ops)))  {
+		nl_cli_fatal(EINVAL, "Application bug: The shared library for "
+			"the qdisc \"%s\" was successfully loaded but it "
+			"seems that module did not register itself");
+	}
+
+	return qm;
+}
+
+void nl_cli_qdisc_register(struct nl_cli_qdisc_module *qm)
+{
+	struct rtnl_qdisc_ops *ops;
+
+	if (!(ops = __rtnl_qdisc_lookup_ops(qm->qm_name))) {
+		nl_cli_fatal(ENOENT, "Unable to register CLI qdisc module "
+		"\"%s\": No matching libnl qdisc module found.", qm->qm_name);
+	}
+
+	if (__nl_cli_qdisc_lookup(ops)) {
+		nl_cli_fatal(EEXIST, "Unable to register CLI qdisc module "
+		"\"%s\": Module already registered.", qm->qm_name);
+	}
+
+	qm->qm_ops = ops;
+	nl_list_add_tail(&qm->qm_list, &qdisc_modules);
+}
+
+void nl_cli_qdisc_unregister(struct nl_cli_qdisc_module *qm)
+{
+	nl_list_del(&qm->qm_list);
+}
+
 /** @} */
diff --git a/src/lib/utils.c b/src/lib/utils.c
index 02a7be1..9375bfc 100644
--- a/src/lib/utils.c
+++ b/src/lib/utils.c
@@ -13,10 +13,25 @@
  * @defgroup cli Command Line Interface API
  *
  * @{
+ *
+ * These modules provide an interface for text based applications. The
+ * functions provided are wrappers for their libnl equivalent with
+ * added error handling. The functions check for allocation failures,
+ * invalid input, and unknown types and will print error messages
+ * accordingly via nl_cli_fatal().
  */
 
 #include <netlink/cli/utils.h>
 
+/**
+ * Parse a text based 32 bit unsigned integer argument
+ * @arg arg		Integer in text form.
+ *
+ * Tries to convert the number provided in arg to a uint32_t. Will call
+ * nl_cli_fatal() if the conversion fails.
+ *
+ * @return 32bit unsigned integer.
+ */
 uint32_t nl_cli_parse_u32(const char *arg)
 {
 	unsigned long lval;
@@ -34,7 +49,7 @@ void nl_cli_print_version(void)
 {
 	printf("libnl tools version %s\n", LIBNL_VERSION);
 	printf(
-	"Copyright (C) 2003-2009 Thomas Graf <tgraf@redhat.com>\n"
+	"Copyright (C) 2003-2010 Thomas Graf <tgraf@redhat.com>\n"
 	"\n"
 	"This program comes with ABSOLUTELY NO WARRANTY. This is free \n"
 	"software, and you are welcome to redistribute it under certain\n"
@@ -44,6 +59,14 @@ void nl_cli_print_version(void)
 	exit(0);
 }
 
+/**
+ * Print error message and quit application
+ * @arg err		Error code.
+ * @arg fmt		Error message.
+ *
+ * Prints the formatted error message to stderr and quits the application
+ * using the provided error code.
+ */
 void nl_cli_fatal(int err, const char *fmt, ...)
 {
 	va_list ap;
@@ -144,4 +167,17 @@ struct nl_cache *nl_cli_alloc_cache(struct nl_sock *sock, const char *name,
 	return cache;
 }
 
+void nl_cli_load_module(const char *prefix, const char *name)
+{
+	char path[FILENAME_MAX+1];
+	void *handle;
+
+	snprintf(path, sizeof(path), "%s/%s/%s.so",
+		 PKGLIBDIR, prefix, name);
+
+	if (!(handle = dlopen(path, RTLD_NOW)))
+		nl_cli_fatal(ENOENT, "Unable to load module \"%s\": %s\n",
+			path, dlerror());
+}
+
 /** @} */