target/linux/generic/backport-4.19/394-v5.1-sch_cake-Interpret-fwmark-parameter-as-a-bitmask.patch

   1 From eab2fc822af38f31fd5f4e731b5d10b94904d919 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
   3 Date: Thu, 14 Mar 2019 23:08:22 +0100
   4 Subject: [PATCH] sch_cake: Interpret fwmark parameter as a bitmask
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 We initially interpreted the fwmark parameter as a flag that simply turned
  10 on the feature, using the whole skb->mark field as the index into the CAKE
  11 tin_order array. However, it is quite common for different applications to
  12 use different parts of the mask field for their own purposes, each using a
  13 different mask.
  14
  15 Support this use of subsets of the mark by interpreting the TCA_CAKE_FWMARK
  16 parameter as a bitmask to apply to the fwmark field when reading it. The
  17 result will be right-shifted by the number of unset lower bits of the mask
  18 before looking up the tin.
  19
  20 In the original commit message we also failed to credit Felix Resch with
  21 originally suggesting the fwmark feature back in 2017; so the Suggested-By
  22 in this commit covers the whole fwmark feature.
  23
  24 Fixes: 0b5c7efdfc6e ("sch_cake: Permit use of connmarks as tin classifiers")
  25 Suggested-by: Felix Resch <fuller@beif.de>
  26 Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
  27 Signed-off-by: David S. Miller <davem@davemloft.net>
  28 Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
  29 ---
  30  net/sched/sch_cake.c | 25 ++++++++++++-------------
  31  1 file changed, 12 insertions(+), 13 deletions(-)
  32
  33 --- a/net/sched/sch_cake.c
  34 +++ b/net/sched/sch_cake.c
  35 @@ -211,6 +211,9 @@ struct cake_sched_data {
  36         u8              ack_filter;
  37         u8              atm_mode;
  38
  39 +       u32             fwmark_mask;
  40 +       u16             fwmark_shft;
  41 +
  42         /* time_next = time_this + ((len * rate_ns) >> rate_shft) */
  43         u16             rate_shft;
  44         ktime_t         time_next_packet;
  45 @@ -258,8 +261,7 @@ enum {
  46         CAKE_FLAG_AUTORATE_INGRESS = BIT(1),
  47         CAKE_FLAG_INGRESS          = BIT(2),
  48         CAKE_FLAG_WASH             = BIT(3),
  49 -       CAKE_FLAG_SPLIT_GSO        = BIT(4),
  50 -       CAKE_FLAG_FWMARK           = BIT(5)
  51 +       CAKE_FLAG_SPLIT_GSO        = BIT(4)
  52  };
  53
  54  /* COBALT operates the Codel and BLUE algorithms in parallel, in order to
  55 @@ -1554,7 +1556,7 @@ static struct cake_tin_data *cake_select
  56                                              struct sk_buff *skb)
  57  {
  58         struct cake_sched_data *q = qdisc_priv(sch);
  59 -       u32 tin;
  60 +       u32 tin, mark;
  61         u8 dscp;
  62
  63         /* Tin selection: Default to diffserv-based selection, allow overriding
  64 @@ -1562,6 +1564,7 @@ static struct cake_tin_data *cake_select
  65          */
  66         dscp = cake_handle_diffserv(skb,
  67                                     q->rate_flags & CAKE_FLAG_WASH);
  68 +       mark = (skb->mark & q->fwmark_mask) >> q->fwmark_shft;
  69
  70         if (q->tin_mode == CAKE_DIFFSERV_BESTEFFORT)
  71                 tin = 0;
  72 @@ -2178,6 +2181,7 @@ static const struct nla_policy cake_poli
  73         [TCA_CAKE_MPU]           = { .type = NLA_U32 },
  74         [TCA_CAKE_INGRESS]       = { .type = NLA_U32 },
  75         [TCA_CAKE_ACK_FILTER]    = { .type = NLA_U32 },
  76 +       [TCA_CAKE_FWMARK]        = { .type = NLA_U32 },
  77  };
  78
  79  static void cake_set_rate(struct cake_tin_data *b, u64 rate, u32 mtu,
  80 @@ -2625,10 +2629,8 @@ static int cake_change(struct Qdisc *sch
  81         }
  82
  83         if (tb[TCA_CAKE_FWMARK]) {
  84 -               if (!!nla_get_u32(tb[TCA_CAKE_FWMARK]))
  85 -                       q->rate_flags |= CAKE_FLAG_FWMARK;
  86 -               else
  87 -                       q->rate_flags &= ~CAKE_FLAG_FWMARK;
  88 +               q->fwmark_mask = nla_get_u32(tb[TCA_CAKE_FWMARK]);
  89 +               q->fwmark_shft = q->fwmark_mask ? __ffs(q->fwmark_mask) : 0;
  90         }
  91
  92         if (q->tins) {
  93 @@ -2790,8 +2792,7 @@ static int cake_dump(struct Qdisc *sch,
  94                         !!(q->rate_flags & CAKE_FLAG_SPLIT_GSO)))
  95                 goto nla_put_failure;
  96
  97 -       if (nla_put_u32(skb, TCA_CAKE_FWMARK,
  98 -                       !!(q->rate_flags & CAKE_FLAG_FWMARK)))
  99 +       if (nla_put_u32(skb, TCA_CAKE_FWMARK, q->fwmark_mask))
 100                 goto nla_put_failure;
 101
 102         return nla_nest_end(skb, opts);