target/linux/generic/backport-4.14/363-netfilter-nf_flow_table-add-support-for-sending-flow.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sun, 25 Feb 2018 15:41:11 +0100
   3 Subject: [PATCH] netfilter: nf_flow_table: add support for sending flows
   4  back to the slow path
   5
   6 Reset the timeout. For TCP, also set the state to indicate to use the
   7 next incoming packets to reset window tracking.
   8 This allows the slow path to take over again once the offload state has
   9 been torn down
  10
  11 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  12 ---
  13
  14 --- a/net/netfilter/nf_flow_table_core.c
  15 +++ b/net/netfilter/nf_flow_table_core.c
  16 @@ -100,6 +100,36 @@ err_ct_refcnt:
  17  }
  18  EXPORT_SYMBOL_GPL(flow_offload_alloc);
  19
  20 +static void flow_offload_fixup_ct_state(struct nf_conn *ct)
  21 +{
  22 +       const struct nf_conntrack_l4proto *l4proto;
  23 +       struct net *net = nf_ct_net(ct);
  24 +       unsigned int *timeouts;
  25 +       unsigned int timeout;
  26 +       int l4num;
  27 +
  28 +       l4num = nf_ct_protonum(ct);
  29 +       l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), l4num);
  30 +       if (!l4proto)
  31 +               return;
  32 +
  33 +       timeouts = l4proto->get_timeouts(net);
  34 +       if (!timeouts)
  35 +               return;
  36 +
  37 +       if (l4num == IPPROTO_TCP) {
  38 +               timeout = timeouts[TCP_CONNTRACK_ESTABLISHED];
  39 +               ct->proto.tcp.state = TCP_CONNTRACK_IGNORE;
  40 +       } else if (l4num == IPPROTO_UDP) {
  41 +               timeout = timeouts[UDP_CT_REPLIED];
  42 +       } else {
  43 +               return;
  44 +       }
  45 +
  46 +       ct->timeout = nfct_time_stamp + timeout;
  47 +       clear_bit(IPS_OFFLOAD_BIT, &ct->status);
  48 +}
  49 +
  50  void flow_offload_free(struct flow_offload *flow)
  51  {
  52         struct flow_offload_entry *e;
  53 @@ -107,7 +137,10 @@ void flow_offload_free(struct flow_offlo
  54         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
  55         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
  56         e = container_of(flow, struct flow_offload_entry, flow);
  57 -       nf_ct_delete(e->ct, 0, 0);
  58 +       if (flow->flags & FLOW_OFFLOAD_DYING)
  59 +               nf_ct_delete(e->ct, 0, 0);
  60 +       else
  61 +               flow_offload_fixup_ct_state(e->ct);
  62         nf_ct_put(e->ct);
  63         kfree_rcu(e, rcu_head);
  64  }