From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roopa Prabhu Subject: Re: [PATCH net-next 2/7] net: rtnetlink: allow only one idx saving stats attribute Date: Wed, 27 Apr 2016 22:18:33 -0700 Message-ID: <57219D29.2080307@cumulusnetworks.com> References: <1461773902-13528-1-git-send-email-nikolay@cumulusnetworks.com> <1461773902-13528-3-git-send-email-nikolay@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, davem@davemloft.net, stephen@networkplumber.org, jhs@mojatatu.com To: Nikolay Aleksandrov Return-path: Received: from mail-pf0-f174.google.com ([209.85.192.174]:36599 "EHLO mail-pf0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753AbcD1FSg (ORCPT ); Thu, 28 Apr 2016 01:18:36 -0400 Received: by mail-pf0-f174.google.com with SMTP id c189so29290122pfb.3 for ; Wed, 27 Apr 2016 22:18:36 -0700 (PDT) In-Reply-To: <1461773902-13528-3-git-send-email-nikolay@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 4/27/16, 9:18 AM, Nikolay Aleksandrov wrote: > We can't allow more than one stats attribute which uses the local idx > since the result will be a mess. This is a simple check to make sure > only one is being used at a time. Later when the filter_mask's 32 bits > are over we can switch to a bitmap. > > Signed-off-by: Nikolay Aleksandrov > --- > include/net/rtnetlink.h | 6 ++++++ > net/core/rtnetlink.c | 17 +++++++++++++++-- > 2 files changed, 21 insertions(+), 2 deletions(-) > > diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h > index 2f87c1ba13de..3f3b0b1b8722 100644 > --- a/include/net/rtnetlink.h > +++ b/include/net/rtnetlink.h > @@ -150,4 +150,10 @@ int rtnl_nla_parse_ifla(struct nlattr **tb, const struct nlattr *head, int len); > > #define MODULE_ALIAS_RTNL_LINK(kind) MODULE_ALIAS("rtnl-link-" kind) > > +/* at most one attribute which can save a local idx is allowed to be set > + * IFLA_STATS_IDX_ATTR_MASK has all the idx saving attributes set and is > + * used to check if more than one is being requested > + */ > +#define IFLA_STATS_IDX_ATTR_MASK 0 > + > #endif > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index aeb2fa9b1cda..ea03b6cd3d3c 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -3512,7 +3512,7 @@ static int rtnl_stats_get(struct sk_buff *skb, struct nlmsghdr *nlh) > struct if_stats_msg *ifsm; > struct net_device *dev = NULL; > struct sk_buff *nskb; > - u32 filter_mask; > + u32 filter_mask, lidx_filter; > int lidx = 0; > int err; > > @@ -3529,6 +3529,14 @@ static int rtnl_stats_get(struct sk_buff *skb, struct nlmsghdr *nlh) > if (!filter_mask) > return -EINVAL; > > + /* only one attribute which can save a local idx is allowed at a time > + * even though rtnl_stats_get doesn't save the lidx, we need to be > + * consistent with the dump side and error out > + */ > + lidx_filter = filter_mask & IFLA_STATS_IDX_ATTR_MASK; > + if (lidx_filter && !is_power_of_2(lidx_filter)) > + return -EINVAL; > + > nskb = nlmsg_new(if_nlmsg_stats_size(dev, filter_mask), GFP_KERNEL); > if (!nskb) > return -ENOBUFS; > @@ -3556,7 +3564,7 @@ static int rtnl_stats_dump(struct sk_buff *skb, struct netlink_callback *cb) > struct net_device *dev; > struct hlist_head *head; > unsigned int flags = NLM_F_MULTI; > - u32 filter_mask = 0; > + u32 filter_mask = 0, lidx_filter; > int err; > > s_h = cb->args[0]; > @@ -3570,6 +3578,11 @@ static int rtnl_stats_dump(struct sk_buff *skb, struct netlink_callback *cb) > if (!filter_mask) > return -EINVAL; > > + /* only one attribute which can save a local idx is allowed at a time */ > + lidx_filter = filter_mask & IFLA_STATS_IDX_ATTR_MASK; > + if (lidx_filter && !is_power_of_2(lidx_filter)) > + return -EINVAL; > + > instead of introducing the restriction at this level, is it possible to use two args for this like below and avoid the restriction ? cb->args[2] = current filter being processed cb->args[3] = private filter idx (your lidx)