target/linux/generic/backport-4.14/363-v4.18-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 +100,43 @@ err_ct_refcnt:
  17  }
  18  EXPORT_SYMBOL_GPL(flow_offload_alloc);
  19
  20 +static void flow_offload_fixup_tcp(struct ip_ct_tcp *tcp)
  21 +{
  22 +       tcp->state = TCP_CONNTRACK_ESTABLISHED;
  23 +       tcp->seen[0].td_maxwin = 0;
  24 +       tcp->seen[1].td_maxwin = 0;
  25 +}
  26 +
  27 +static void flow_offload_fixup_ct_state(struct nf_conn *ct)
  28 +{
  29 +       const struct nf_conntrack_l4proto *l4proto;
  30 +       struct net *net = nf_ct_net(ct);
  31 +       unsigned int *timeouts;
  32 +       unsigned int timeout;
  33 +       int l4num;
  34 +
  35 +       l4num = nf_ct_protonum(ct);
  36 +       if (l4num == IPPROTO_TCP)
  37 +               flow_offload_fixup_tcp(&ct->proto.tcp);
  38 +
  39 +       l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), l4num);
  40 +       if (!l4proto)
  41 +               return;
  42 +
  43 +       timeouts = l4proto->get_timeouts(net);
  44 +       if (!timeouts)
  45 +               return;
  46 +
  47 +       if (l4num == IPPROTO_TCP)
  48 +               timeout = timeouts[TCP_CONNTRACK_ESTABLISHED];
  49 +       else if (l4num == IPPROTO_UDP)
  50 +               timeout = timeouts[UDP_CT_REPLIED];
  51 +       else
  52 +               return;
  53 +
  54 +       ct->timeout = nfct_time_stamp + timeout;
  55 +}
  56 +
  57  void flow_offload_free(struct flow_offload *flow)
  58  {
  59         struct flow_offload_entry *e;
  60 @@ -107,7 +144,8 @@ void flow_offload_free(struct flow_offlo
  61         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_cache);
  62         dst_release(flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_cache);
  63         e = container_of(flow, struct flow_offload_entry, flow);
  64 -       nf_ct_delete(e->ct, 0, 0);
  65 +       if (flow->flags & FLOW_OFFLOAD_DYING)
  66 +               nf_ct_delete(e->ct, 0, 0);
  67         nf_ct_put(e->ct);
  68         kfree_rcu(e, rcu_head);
  69  }
  70 @@ -164,6 +202,8 @@ EXPORT_SYMBOL_GPL(flow_offload_add);
  71  static void flow_offload_del(struct nf_flowtable *flow_table,
  72                              struct flow_offload *flow)
  73  {
  74 +       struct flow_offload_entry *e;
  75 +
  76         rhashtable_remove_fast(&flow_table->rhashtable,
  77                                &flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].node,
  78                                nf_flow_offload_rhash_params);
  79 @@ -171,12 +211,20 @@ static void flow_offload_del(struct nf_f
  80                                &flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].node,
  81                                nf_flow_offload_rhash_params);
  82
  83 +       e = container_of(flow, struct flow_offload_entry, flow);
  84 +       clear_bit(IPS_OFFLOAD_BIT, &e->ct->status);
  85 +
  86         flow_offload_free(flow);
  87  }
  88
  89  void flow_offload_teardown(struct flow_offload *flow)
  90  {
  91 +       struct flow_offload_entry *e;
  92 +
  93         flow->flags |= FLOW_OFFLOAD_TEARDOWN;
  94 +
  95 +       e = container_of(flow, struct flow_offload_entry, flow);
  96 +       flow_offload_fixup_ct_state(e->ct);
  97  }
  98  EXPORT_SYMBOL_GPL(flow_offload_teardown);
  99