From 3e805ad288c524bb65aad3f1e004402223d3d504 Mon Sep 17 00:00:00 2001 From: Asbjoern Sloth Toennesen Date: Mon, 12 Aug 2013 16:30:09 +0000 Subject: [PATCH] rtnetlink: rtnl_bridge_getlink: Call nlmsg_find_attr() with ifinfomsg header Fix the iproute2 command `bridge vlan show`, after switching from rtgenmsg to ifinfomsg. Let's start with a little history: Feb 20: Vlad Yasevich got his VLAN-aware bridge patchset included in the 3.9 merge window. In the kernel commit 6cbdceeb, he added attribute support to bridge GETLINK requests sent with rtgenmsg. Mar 6th: Vlad got this iproute2 reference implementation of the bridge vlan netlink interface accepted (iproute2 9eff0e5c) Apr 25th: iproute2 switched from using rtgenmsg to ifinfomsg (63338dca) http://patchwork.ozlabs.org/patch/239602/ http://marc.info/?t=136680900700007 Apr 28th: Linus released 3.9 Apr 30th: Stephen released iproute2 3.9.0 The `bridge vlan show` command haven't been working since the switch to ifinfomsg, or in a released version of iproute2. Since the kernel side only supports rtgenmsg, which iproute2 switched away from just prior to the iproute2 3.9.0 release. I haven't been able to find any documentation, about neither rtgenmsg nor ifinfomsg, and in which situation to use which, but kernel commit 88c5b5ce seams to suggest that ifinfomsg should be used. Fixing this in kernel will break compatibility, but I doubt that anybody have been using it due to this bug in the user space reference implementation, at least not without noticing this bug. That said the functionality is still fully functional in 3.9, when reversing iproute2 commit 63338dca. This could also be fixed in iproute2, but thats an ugly patch that would reintroduce rtgenmsg in iproute2, and from searching in netdev it seams like rtgenmsg usage is discouraged. I'm assuming that the only reason that Vlad implemented the kernel side to use rtgenmsg, was because iproute2 was using it at the time. Signed-off-by: Asbjoern Sloth Toennesen Reviewed-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 82d968527121..ca198c1d1d30 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2384,7 +2384,7 @@ static int rtnl_bridge_getlink(struct sk_buff *skb, struct netlink_callback *cb) struct nlattr *extfilt; u32 filter_mask = 0; - extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct rtgenmsg), + extfilt = nlmsg_find_attr(cb->nlh, sizeof(struct ifinfomsg), IFLA_EXT_MASK); if (extfilt) filter_mask = nla_get_u32(extfilt); -- 2.39.5