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enable transition to sysfs-only bridge manipulation

PATCH In review Bernhard Fischer 2 participants 3 messages May 2, 2008

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Networking Ethernet bridge
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Bernhard Fischer

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#0 lore raw

PATCH 1/1 enable transition to sysfs-only bridge manipulation

Hi,

It was rumored that the ioctl interface for bridges is deprecated. There is, however, one crucial gap when trying to implement brctl without using any ioctl: AFAICS it is impossible to create a bridge via sysfs.

The attached quick.. erm patch strives to fill this gap. Some further details are at the top of the patchlet which received only cursory testing, fwiw.

Thanks and cheers,
Bernhard

enable transition to sysfs-only bridge manipulation

All bridge-operations except the creation of a bridge are already operable via sysfs. The attached patchlet provides means to fill this gap in order to completely deprecate the ioctl interface to bridges.

  $ echo add mybr0 > /sys/class/bridge/ctrl
  $ echo add mybr1 > /sys/class/bridge/ctrl
  $ echo del mybr1 > /sys/class/bridge/ctrl

add/remove: 3/0 grow/shrink: 4/0 up/down: 490/0 (490)

function                                     old     new   delta
brctl                                          -     230    +230
init_module                                  186     265     +79
br_init                                      186     265     +79
cleanup_module                               103     142     +39
br_deinit                                    103     142     +39

class_attr_ctrl - 20 +20
br_class - 4 +4

Signed-off-by Bernhard Fischer <[email protected]>
net/bridge/br.c +85 -0
diff -rdup linux-2.6.25.oorig/net/bridge/br.c linux-2.6.25/net/bridge/br.c
@@ -20,11 +20,91 @@
 #include <linux/init.h>
 #include <linux/llc.h>
 #include <net/llc.h>
+#include <linux/ctype.h> /* isspace() */
 
 #include "br_private.h"
 
 int (*br_should_route_hook)(struct sk_buff *skb);
 
+#ifdef CONFIG_SYSFS
+static ssize_t brctl(struct class *cls, const char *buf, size_t buf_len)
+{
+	unsigned op_add;
+	size_t sz = buf_len;
+	char *br;
+	int ret;
+
+	if (sz < 3)
+		goto err;
+
+	if (buf[0] == 'a')
+		op_add = 1;
+	else if (buf[0] == 'd')
+		op_add = 0;
+	else
+		goto err;
+
+	if (buf[buf_len - 1] == '\n')
+		--sz;
+
+	/* skip to bridge name */
+	while (!isspace(*buf)) {
+		++buf;
+		--sz;
+	}
+	while (isspace(*buf)) {
+		++buf;
+		--sz;
+	}
+	if (!buf || !sz)
+		goto err;
+	br = kzalloc(sz, GFP_KERNEL);
+	if (!br)
+		return -ENOMEM;
+	strncpy(br, buf, sz);
+
+	if (op_add)
+		ret = br_add_bridge(br);
+	else
+		ret = br_del_bridge(br);
+	kfree(br);
+	return (ret < 0) ? ret : buf_len;
+err:
+	return -EINVAL;
+}
+static struct class *br_class;
+static CLASS_ATTR(ctrl, 0200, NULL, brctl);
+static inline int br_sysfs_init(void)
+{
+	int ret;
+
+	br_class = class_create(THIS_MODULE, "bridge");
+	if (IS_ERR(br_class))
+		return PTR_ERR(br_class);
+
+	ret = class_create_file(br_class, &class_attr_ctrl);
+	if (ret < 0) {
+		class_destroy(br_class);
+		br_class = NULL;
+	}
+	return ret;
+}
+static inline void br_sysfs_fini(void)
+{
+	if (br_class) {
+		class_remove_file(br_class, &class_attr_ctrl);
+		class_destroy(br_class);
+		br_class = NULL;
+	}
+}
+#else
+static inline int br_sysfs_init(void)
+{
+	return 0;
+}
+static inline void br_sysfs_fini(void) {;}
+#endif
+
 static struct llc_sap *br_stp_sap;
 
 static int __init br_init(void)

@@ -53,6 +133,10 @@ static int __init br_init(void)
 	if (err)
 		goto err_out3;
 
+	err = br_sysfs_init();
+	if (err)
+		goto err_out3;
+
 	brioctl_set(br_ioctl_deviceless_stub);
 	br_handle_frame_hook = br_handle_frame;
 

@@ -73,6 +157,7 @@ err_out:
 
 static void __exit br_deinit(void)
 {
+	br_sysfs_fini();
 	rcu_assign_pointer(br_stp_sap->rcv_func, NULL);
 
 	br_netlink_fini();
#1 lore raw
Quoted 7 lines · On Fri, 2 May 2008 11:01:38 +0200 Bernhard Fischer <[email protected]>…

Hi,

It was rumored that the ioctl interface for bridges is deprecated. There is, however, one crucial gap when trying to implement brctl without using any ioctl: AFAICS it is impossible to create a bridge via sysfs.

Quoted 6 lines

The attached quick.. erm patch strives to fill this gap. Some further details are at the top of the patchlet which received only cursory testing, fwiw.

Thanks and cheers,
Bernhard

Why bother. The old API has to live on because it part of the kernel ABI.

author
#2 lore raw
Quoted 14 lines · Stephen Hemminger
Quoted 11 lines · On Fri, 2 May 2008 11:01:38 +0200 Bernhard Fischer <[email protected]>…

Hi,

It was rumored that the ioctl interface for bridges is deprecated. There is, however, one crucial gap when trying to implement brctl without using any ioctl: AFAICS it is impossible to create a bridge via sysfs.

The attached quick.. erm patch strives to fill this gap. Some further details are at the top of the patchlet which received only cursory testing, fwiw.

Quoted 5 lines
Quoted 2 lines

Thanks and cheers,
Bernhard

Why bother. The old API has to live on because it part of the kernel ABI.

I'm bothering since i either want the ioctl interface _or_ the sysfs interface. I currently use the ioctl interface but as long as the sysfs is incomplete i cannot switch to it even if i wanted.