From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vlad Yasevich Subject: Re: [RFC PATCH bridge 5/5] bridge: Add sysfs interface to display VLANS Date: Thu, 30 Aug 2012 10:36:34 -0400 Message-ID: <503F7A72.6070101@redhat.com> References: <1345750195-31598-1-git-send-email-vyasevic@redhat.com> <1345750195-31598-6-git-send-email-vyasevic@redhat.com> <20120830122724.GC20228@redhat.com> <503F731C.1070208@redhat.com> <20120830142609.GE21132@redhat.com> Reply-To: vyasevic@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6569 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752084Ab2H3Ogf (ORCPT ); Thu, 30 Aug 2012 10:36:35 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q7UEaZHT001067 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 30 Aug 2012 10:36:35 -0400 In-Reply-To: <20120830142609.GE21132@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On 08/30/2012 10:26 AM, Michael S. Tsirkin wrote: > On Thu, Aug 30, 2012 at 10:05:16AM -0400, Vlad Yasevich wrote: >> On 08/30/2012 08:27 AM, Michael S. Tsirkin wrote: >>> On Thu, Aug 23, 2012 at 03:29:55PM -0400, Vlad Yasevich wrote: >>>> Add a binary sysfs file that will dump out vlans currently configured on the >>>> port. >>>> >>>> Signed-off-by: Vlad Yasevich >>> >>> So what's the format here? I could not tell. >>> List of vlans? Why binary? Why not make it text in that case? >>> This would also allow reporting "all" if filtering >>> is disabled and "untagged" for untagged packets. >> >> I decided to do binary because text may result in more then page >> worth of data. > > Well yes, you need 3 bytes to print a vid and 1 extra for a space. 4 bytes per vid and 1 for space or NULL. > But > in binary, 2 bytes per VID and there are 4K valid VIDs so binary needs > more than 1 page too? > > If using binary I would go for bit per valid bit > this solves it nicely. True. The tool reads it in chunks. I thought about dumping the bitmap, but that meant that made the tool more complex as it had to know the bitmap construction. > We can have a separate field that shows whether untagged > packets are filtered. > >> The display tool will know how to display things >> properly. >> >> -vlad > > I think you know that one of the points of sysfs > is to allow use without tools. > Tools are happier using other interfaces such as > ioctl or netlink. > I initially though of creating a sysfs object per vlan. That would have made it easy to see which vlans are configured without any tools. But that could result in a lot of objects being created, so I abandoned it. I did think about a text interface, but due to a page of output limitation, I didn't go that route. The reason is that if someone cats the file, they may not see all the vlans configured. So I decided on the binary interface, since a binary interface with a tool to read it could avoid the single page limitation. -vlad > > >>> >>>> --- >>>> include/linux/if_bridge.h | 1 + >>>> net/bridge/br_if.c | 34 ++++++++++++++++++++++++++++++++++ >>>> net/bridge/br_private.h | 2 ++ >>>> net/bridge/br_sysfs_if.c | 28 ++++++++++++++++++++++++++++ >>>> 4 files changed, 65 insertions(+), 0 deletions(-) >>>> >>>> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h >>>> index ab750dd..d0f869b 100644 >>>> --- a/include/linux/if_bridge.h >>>> +++ b/include/linux/if_bridge.h >>>> @@ -20,6 +20,7 @@ >>>> #define SYSFS_BRIDGE_PORT_SUBDIR "brif" >>>> #define SYSFS_BRIDGE_PORT_ATTR "brport" >>>> #define SYSFS_BRIDGE_PORT_LINK "bridge" >>>> +#define SYSFS_BRIDGE_PORT_VLANS "vlans" >>>> >>>> #define BRCTL_VERSION 1 >>>> >>>> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c >>>> index 90c1038..3963748 100644 >>>> --- a/net/bridge/br_if.c >>>> +++ b/net/bridge/br_if.c >>>> @@ -510,6 +510,40 @@ int br_del_port_vlan(struct net_bridge_port *p, unsigned long vlan) >>>> return 0; >>>> } >>>> >>>> +size_t br_port_fill_vlans(struct net_bridge_port *p, char* buf, >>>> + unsigned long max, unsigned long skip) >>>> +{ >>>> + unsigned long *map; >>>> + unsigned short *vid = (unsigned short *)buf; >>>> + unsigned short i; >>>> + int num = 0; >>>> + >>>> + if (skip > (VLAN_N_VID+1)) >>>> + return -EINVAL; >>>> + >>>> + memset(buf, 0, max * sizeof(unsigned short)); >>> >>> Isn't max is in bytes? why is this safe? >>> >>>> + >>>> + rcu_read_lock(); >>>> + map = rcu_dereference(p->vlan_map); >>>> + if (!map) >>>> + goto out; >>>> + >>>> + for (i = skip + 1; i < VLAN_N_VID + 1; i++) { >>> >>> Isn't skip in bytes too? Why do you compare it to i which is >>> in dwords? >>> >>>> + if (test_bit(i, map)) { >>>> + if (num > max) >>>> + goto out; >>>> + >>>> + *vid = i-1; >>>> + vid++; >>>> + num++; >>>> + } >>>> + } >>>> +out: >>>> + rcu_read_unlock(); >>>> + >>>> + return num*sizeof(unsigned short); >>>> +} >>>> + >>>> void __net_exit br_net_exit(struct net *net) >>>> { >>>> struct net_device *dev; >>>> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h >>>> index 5639c1c..cf95cd7 100644 >>>> --- a/net/bridge/br_private.h >>>> +++ b/net/bridge/br_private.h >>>> @@ -404,6 +404,8 @@ extern netdev_features_t br_features_recompute(struct net_bridge *br, >>>> netdev_features_t features); >>>> extern int br_set_port_vlan(struct net_bridge_port *p, unsigned long vid); >>>> extern int br_del_port_vlan(struct net_bridge_port *p, unsigned long vid); >>>> +extern size_t br_port_fill_vlans(struct net_bridge_port *p, char *buf, >>>> + unsigned long max, unsigned long skip); >>>> >>>> /* br_input.c */ >>>> extern int br_handle_frame_finish(struct sk_buff *skb); >>>> diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c >>>> index 13b36bd..a81e2ef 100644 >>>> --- a/net/bridge/br_sysfs_if.c >>>> +++ b/net/bridge/br_sysfs_if.c >>>> @@ -234,6 +234,29 @@ const struct sysfs_ops brport_sysfs_ops = { >>>> }; >>>> >>>> /* >>>> + * Export the vlan table for a given port as a binary file. >>>> + * The records are unsgined shorts. >>>> + * >>>> + * Returns the number of bytes read. >>>> + */ >>>> +static ssize_t brport_vlans_read(struct file *filp, struct kobject *kobj, >>>> + struct bin_attribute *bin_attr, >>>> + char *buf, loff_t off, size_t count) >>>> +{ >>>> + struct net_bridge_port *p = to_brport(kobj); >>>> + >>>> + return br_port_fill_vlans(p, buf, >>>> + count/sizeof(unsigned short), >>>> + off/sizeof(unsigned short)); >>>> +} >>>> + >>>> +static struct bin_attribute port_vlans = { >>>> + .attr = { .name = SYSFS_BRIDGE_PORT_VLANS, >>>> + .mode = S_IRUGO, }, >>>> + .read = brport_vlans_read, >>>> +}; >>>> + >>>> +/* >>>> * Add sysfs entries to ethernet device added to a bridge. >>>> * Creates a brport subdirectory with bridge attributes. >>>> * Puts symlink in bridge's brif subdirectory >>>> @@ -255,6 +278,11 @@ int br_sysfs_addif(struct net_bridge_port *p) >>>> return err; >>>> } >>>> >>>> + err = sysfs_create_bin_file(&p->kobj, &port_vlans); >>>> + if (err) { >>>> + return err; >>>> + } >>>> + >>>> strlcpy(p->sysfs_name, p->dev->name, IFNAMSIZ); >>>> return sysfs_create_link(br->ifobj, &p->kobj, p->sysfs_name); >>>> } >>>> -- >>>> 1.7.7.6 >>>> >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe netdev" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html