[ovs-dev] [PATCH 1/2] netdev: Allow providers to be managed at runtime.
Jesse Gross
jesse at nicira.com
Fri Jan 29 20:39:46 UTC 2010
The list of netdev providers was previously staticly defined at
compile time. This allows new providers to be added and removed
at runtime.
---
lib/netdev-provider.h | 8 ++--
lib/netdev.c | 124 +++++++++++++++++++++++++++++++++++++-----------
lib/netdev.h | 6 ++-
3 files changed, 104 insertions(+), 34 deletions(-)
diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h
index a6c0fd8..43a330c 100644
--- a/lib/netdev-provider.h
+++ b/lib/netdev-provider.h
@@ -107,12 +107,12 @@ struct netdev_class {
* the system. */
const char *type;
- /* Called only once, at program startup. Returning an error from this
- * function will prevent any network device in this class from being
- * opened.
+ /* Called when the netdev provider is registered, typically at program
+ * startup. Returning an error from this function will prevent any network
+ * device in this class from being opened.
*
* This function may be set to null if a network device class needs no
- * initialization at program startup. */
+ * initialization at registration time. */
int (*init)(void);
/* Performs periodic work needed by netdevs of this class. May be null if
diff --git a/lib/netdev.c b/lib/netdev.c
index 84efc6b..f0512d5 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -40,12 +40,15 @@
#define THIS_MODULE VLM_netdev
#include "vlog.h"
-static const struct netdev_class *netdev_classes[] = {
+static const struct netdev_class *base_netdev_classes[] = {
&netdev_linux_class,
&netdev_tap_class,
&netdev_gre_class,
};
-static int n_netdev_classes = ARRAY_SIZE(netdev_classes);
+
+static const struct netdev_class **netdev_classes;
+static size_t n_netdev_classes;
+static size_t allocated_netdev_classes;
/* All created network devices. */
static struct shash netdev_dev_shash = SHASH_INITIALIZER(&netdev_dev_shash);
@@ -61,43 +64,21 @@ static void close_all_netdevs(void *aux UNUSED);
static int restore_flags(struct netdev *netdev);
void update_device_args(struct netdev_dev *, const struct shash *args);
-/* Attempts to initialize the netdev module. Returns 0 if successful,
- * otherwise a positive errno value.
- *
- * Calling this function is optional. If not called explicitly, it will
- * automatically be called upon the first attempt to open or create a
- * network device. */
-int
+static void
netdev_initialize(void)
{
static int status = -1;
if (status < 0) {
- int i, j;
+ int i;
fatal_signal_add_hook(close_all_netdevs, NULL, NULL, true);
status = 0;
- for (i = j = 0; i < n_netdev_classes; i++) {
- const struct netdev_class *class = netdev_classes[i];
- if (class->init) {
- int retval = class->init();
- if (!retval) {
- netdev_classes[j++] = class;
- } else {
- VLOG_ERR("failed to initialize %s network device "
- "class: %s", class->type, strerror(retval));
- if (!status) {
- status = retval;
- }
- }
- } else {
- netdev_classes[j++] = class;
- }
+ for (i = 0; i < ARRAY_SIZE(base_netdev_classes); i++) {
+ netdev_register_provider(base_netdev_classes[i]);
}
- n_netdev_classes = j;
}
- return status;
}
/* Performs periodic work needed by all the various kinds of netdevs.
@@ -132,6 +113,91 @@ netdev_wait(void)
}
}
+/* Initializes and registers a new netdev provider. After successful
+ * registration, new netdevs of that type can be opened using netdev_open(). */
+int
+netdev_register_provider(const struct netdev_class *new_class)
+{
+ int i;
+
+ for (i = 0; i < n_netdev_classes; i++) {
+ if (!strcmp(netdev_classes[i]->type, new_class->type)) {
+ VLOG_WARN("attempted to register duplicate netdev provider: "
+ "%s", new_class->type);
+ return EEXIST;
+ }
+ }
+
+ if (new_class->init) {
+ int error = new_class->init();
+ if (error) {
+ VLOG_ERR("failed to initialize %s network device "
+ "class: %s", new_class->type, strerror(error));
+ return error;
+ }
+ }
+
+ if (n_netdev_classes >= allocated_netdev_classes) {
+ netdev_classes = x2nrealloc(netdev_classes,
+ &allocated_netdev_classes,
+ sizeof *netdev_classes);
+ }
+ netdev_classes[n_netdev_classes++] = new_class;
+
+ return 0;
+}
+
+/* Unregisters a netdev provider. 'del_class' must have been previously
+ * registered and not currently be in use by any netdevs. After unregistration
+ * new netdevs of that type cannot be opened using netdev_open(). */
+int
+netdev_unregister_provider(const struct netdev_class *del_class)
+{
+ int i;
+
+ for (i = 0; i < n_netdev_classes; i++) {
+
+ if (netdev_classes[i] == del_class) {
+ struct shash_node *node;
+
+ SHASH_FOR_EACH(node, &netdev_dev_shash) {
+ struct netdev_dev *netdev_dev = node->data;
+ if (netdev_dev->class == del_class) {
+ VLOG_WARN("attempted to unregister in use netdev provider: "
+ "%s", del_class->type);
+ return EBUSY;
+ }
+ }
+
+ if (i != n_netdev_classes - 1) {
+ memmove(netdev_classes + i, netdev_classes + i + 1,
+ (n_netdev_classes - (i + 1)) * sizeof *netdev_classes);
+ }
+ n_netdev_classes--;
+
+ return 0;
+ }
+ }
+
+ VLOG_WARN("attempted to unregister a netdev provider that is not "
+ "registered: %s", del_class->type);
+ return EAFNOSUPPORT;
+}
+
+/* Clears 'types' and enumerates the types of all currently registered netdev
+ * providers into it. The caller must first initialize the svec. */
+void
+netdev_enumerate_types(struct svec *types)
+{
+ int i;
+
+ svec_clear(types);
+
+ for (i = 0; i < n_netdev_classes; i++) {
+ svec_add(types, netdev_classes[i]->type);
+ }
+}
+
/* Compares 'args' to those used to those used by 'dev'. Returns true
* if the arguments are the same, false otherwise. Does not update the
* values stored in 'dev'. */
@@ -228,7 +294,7 @@ create_device(struct netdev_options *options, struct netdev_dev **netdev_devp)
VLOG_WARN("could not create netdev %s of unknown type %s", options->name,
options->type);
- return EINVAL;
+ return EAFNOSUPPORT;
}
/* Opens the network device named 'name' (e.g. "eth0") and returns zero if
diff --git a/lib/netdev.h b/lib/netdev.h
index 3f6d5ea..0cc22b6 100644
--- a/lib/netdev.h
+++ b/lib/netdev.h
@@ -86,11 +86,15 @@ struct netdev_options {
};
struct netdev;
+struct netdev_class;
-int netdev_initialize(void);
void netdev_run(void);
void netdev_wait(void);
+int netdev_register_provider(const struct netdev_class *);
+int netdev_unregister_provider(const struct netdev_class *);
+void netdev_enumerate_types(struct svec *types);
+
int netdev_open(struct netdev_options *, struct netdev **);
int netdev_open_default(const char *name, struct netdev **);
int netdev_reconfigure(struct netdev *, const struct shash *args);
--
1.6.3.3
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