target/linux/generic/backport-5.10/610-v5.13-00-netfilter-flowtable-add-hash-offset-field-to-tuple.patch

   1 From: Pablo Neira Ayuso <pablo@netfilter.org>
   2 Date: Fri, 20 Nov 2020 13:49:13 +0100
   3 Subject: [PATCH] netfilter: flowtable: add hash offset field to tuple
   4
   5 Add a placeholder field to calculate hash tuple offset. Similar to
   6 2c407aca6497 ("netfilter: conntrack: avoid gcc-10 zero-length-bounds
   7 warning").
   8
   9 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  10 ---
  11
  12 --- a/include/net/netfilter/nf_flow_table.h
  13 +++ b/include/net/netfilter/nf_flow_table.h
  14 @@ -107,6 +107,10 @@ struct flow_offload_tuple {
  15
  16         u8                              l3proto;
  17         u8                              l4proto;
  18 +
  19 +       /* All members above are keys for lookups, see flow_offload_hash(). */
  20 +       struct { }                      __hash;
  21 +
  22         u8                              dir;
  23
  24         u16                             mtu;
  25 --- a/net/netfilter/nf_flow_table_core.c
  26 +++ b/net/netfilter/nf_flow_table_core.c
  27 @@ -191,14 +191,14 @@ static u32 flow_offload_hash(const void
  28  {
  29         const struct flow_offload_tuple *tuple = data;
  30
  31 -       return jhash(tuple, offsetof(struct flow_offload_tuple, dir), seed);
  32 +       return jhash(tuple, offsetof(struct flow_offload_tuple, __hash), seed);
  33  }
  34
  35  static u32 flow_offload_hash_obj(const void *data, u32 len, u32 seed)
  36  {
  37         const struct flow_offload_tuple_rhash *tuplehash = data;
  38
  39 -       return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, dir), seed);
  40 +       return jhash(&tuplehash->tuple, offsetof(struct flow_offload_tuple, __hash), seed);
  41  }
  42
  43  static int flow_offload_hash_cmp(struct rhashtable_compare_arg *arg,
  44 @@ -207,7 +207,7 @@ static int flow_offload_hash_cmp(struct
  45         const struct flow_offload_tuple *tuple = arg->key;
  46         const struct flow_offload_tuple_rhash *x = ptr;
  47
  48 -       if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, dir)))
  49 +       if (memcmp(&x->tuple, tuple, offsetof(struct flow_offload_tuple, __hash)))
  50                 return 1;
  51
  52         return 0;