target/linux/generic/backport-5.10/610-v5.13-18-netfilter-flowtable-use-dev_fill_forward_path-to-obt.patch

   1 From: Pablo Neira Ayuso <pablo@netfilter.org>
   2 Date: Wed, 24 Mar 2021 02:30:39 +0100
   3 Subject: [PATCH] netfilter: flowtable: use dev_fill_forward_path() to
   4  obtain ingress device
   5
   6 Obtain the ingress device in the tuple from the route in the reply
   7 direction. Use dev_fill_forward_path() instead to get the real ingress
   8 device for this flow.
   9
  10 Fall back to use the ingress device that the IP forwarding route
  11 provides if:
  12
  13 - dev_fill_forward_path() finds no real ingress device.
  14 - the ingress device that is obtained is not part of the flowtable
  15   devices.
  16 - this route has a xfrm policy.
  17
  18 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  19 ---
  20
  21 --- a/include/net/netfilter/nf_flow_table.h
  22 +++ b/include/net/netfilter/nf_flow_table.h
  23 @@ -164,6 +164,9 @@ static inline __s32 nf_flow_timeout_delt
  24  struct nf_flow_route {
  25         struct {
  26                 struct dst_entry                *dst;
  27 +               struct {
  28 +                       u32                     ifindex;
  29 +               } in;
  30                 enum flow_offload_xmit_type     xmit_type;
  31         } tuple[FLOW_OFFLOAD_DIR_MAX];
  32  };
  33 --- a/net/netfilter/nf_flow_table_core.c
  34 +++ b/net/netfilter/nf_flow_table_core.c
  35 @@ -79,7 +79,6 @@ static int flow_offload_fill_route(struc
  36                                    enum flow_offload_tuple_dir dir)
  37  {
  38         struct flow_offload_tuple *flow_tuple = &flow->tuplehash[dir].tuple;
  39 -       struct dst_entry *other_dst = route->tuple[!dir].dst;
  40         struct dst_entry *dst = route->tuple[dir].dst;
  41
  42         if (!dst_hold_safe(route->tuple[dir].dst))
  43 @@ -94,7 +93,7 @@ static int flow_offload_fill_route(struc
  44                 break;
  45         }
  46
  47 -       flow_tuple->iifidx = other_dst->dev->ifindex;
  48 +       flow_tuple->iifidx = route->tuple[dir].in.ifindex;
  49         flow_tuple->xmit_type = route->tuple[dir].xmit_type;
  50         flow_tuple->dst_cache = dst;
  51
  52 --- a/net/netfilter/nft_flow_offload.c
  53 +++ b/net/netfilter/nft_flow_offload.c
  54 @@ -31,14 +31,104 @@ static void nft_default_forward_path(str
  55                                      struct dst_entry *dst_cache,
  56                                      enum ip_conntrack_dir dir)
  57  {
  58 +       route->tuple[!dir].in.ifindex   = dst_cache->dev->ifindex;
  59         route->tuple[dir].dst           = dst_cache;
  60         route->tuple[dir].xmit_type     = nft_xmit_type(dst_cache);
  61  }
  62
  63 +static int nft_dev_fill_forward_path(const struct nf_flow_route *route,
  64 +                                    const struct dst_entry *dst_cache,
  65 +                                    const struct nf_conn *ct,
  66 +                                    enum ip_conntrack_dir dir,
  67 +                                    struct net_device_path_stack *stack)
  68 +{
  69 +       const void *daddr = &ct->tuplehash[!dir].tuple.src.u3;
  70 +       struct net_device *dev = dst_cache->dev;
  71 +       unsigned char ha[ETH_ALEN];
  72 +       struct neighbour *n;
  73 +       u8 nud_state;
  74 +
  75 +       n = dst_neigh_lookup(dst_cache, daddr);
  76 +       if (!n)
  77 +               return -1;
  78 +
  79 +       read_lock_bh(&n->lock);
  80 +       nud_state = n->nud_state;
  81 +       ether_addr_copy(ha, n->ha);
  82 +       read_unlock_bh(&n->lock);
  83 +       neigh_release(n);
  84 +
  85 +       if (!(nud_state & NUD_VALID))
  86 +               return -1;
  87 +
  88 +       return dev_fill_forward_path(dev, ha, stack);
  89 +}
  90 +
  91 +struct nft_forward_info {
  92 +       const struct net_device *indev;
  93 +};
  94 +
  95 +static void nft_dev_path_info(const struct net_device_path_stack *stack,
  96 +                             struct nft_forward_info *info)
  97 +{
  98 +       const struct net_device_path *path;
  99 +       int i;
 100 +
 101 +       for (i = 0; i < stack->num_paths; i++) {
 102 +               path = &stack->path[i];
 103 +               switch (path->type) {
 104 +               case DEV_PATH_ETHERNET:
 105 +                       info->indev = path->dev;
 106 +                       break;
 107 +               case DEV_PATH_VLAN:
 108 +               case DEV_PATH_BRIDGE:
 109 +               default:
 110 +                       info->indev = NULL;
 111 +                       break;
 112 +               }
 113 +       }
 114 +}
 115 +
 116 +static bool nft_flowtable_find_dev(const struct net_device *dev,
 117 +                                  struct nft_flowtable *ft)
 118 +{
 119 +       struct nft_hook *hook;
 120 +       bool found = false;
 121 +
 122 +       list_for_each_entry_rcu(hook, &ft->hook_list, list) {
 123 +               if (hook->ops.dev != dev)
 124 +                       continue;
 125 +
 126 +               found = true;
 127 +               break;
 128 +       }
 129 +
 130 +       return found;
 131 +}
 132 +
 133 +static void nft_dev_forward_path(struct nf_flow_route *route,
 134 +                                const struct nf_conn *ct,
 135 +                                enum ip_conntrack_dir dir,
 136 +                                struct nft_flowtable *ft)
 137 +{
 138 +       const struct dst_entry *dst = route->tuple[dir].dst;
 139 +       struct net_device_path_stack stack;
 140 +       struct nft_forward_info info = {};
 141 +
 142 +       if (nft_dev_fill_forward_path(route, dst, ct, dir, &stack) >= 0)
 143 +               nft_dev_path_info(&stack, &info);
 144 +
 145 +       if (!info.indev || !nft_flowtable_find_dev(info.indev, ft))
 146 +               return;
 147 +
 148 +       route->tuple[!dir].in.ifindex = info.indev->ifindex;
 149 +}
 150 +
 151  static int nft_flow_route(const struct nft_pktinfo *pkt,
 152                           const struct nf_conn *ct,
 153                           struct nf_flow_route *route,
 154 -                         enum ip_conntrack_dir dir)
 155 +                         enum ip_conntrack_dir dir,
 156 +                         struct nft_flowtable *ft)
 157  {
 158         struct dst_entry *this_dst = skb_dst(pkt->skb);
 159         struct dst_entry *other_dst = NULL;
 160 @@ -63,6 +153,12 @@ static int nft_flow_route(const struct n
 161         nft_default_forward_path(route, this_dst, dir);
 162         nft_default_forward_path(route, other_dst, !dir);
 163
 164 +       if (route->tuple[dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH &&
 165 +           route->tuple[!dir].xmit_type == FLOW_OFFLOAD_XMIT_NEIGH) {
 166 +               nft_dev_forward_path(route, ct, dir, ft);
 167 +               nft_dev_forward_path(route, ct, !dir, ft);
 168 +       }
 169 +
 170         return 0;
 171  }
 172
 173 @@ -90,8 +186,8 @@ static void nft_flow_offload_eval(const
 174         struct nft_flow_offload *priv = nft_expr_priv(expr);
 175         struct nf_flowtable *flowtable = &priv->flowtable->data;
 176         struct tcphdr _tcph, *tcph = NULL;
 177 +       struct nf_flow_route route = {};
 178         enum ip_conntrack_info ctinfo;
 179 -       struct nf_flow_route route;
 180         struct flow_offload *flow;
 181         enum ip_conntrack_dir dir;
 182         struct nf_conn *ct;
 183 @@ -128,7 +224,7 @@ static void nft_flow_offload_eval(const
 184                 goto out;
 185
 186         dir = CTINFO2DIR(ctinfo);
 187 -       if (nft_flow_route(pkt, ct, &route, dir) < 0)
 188 +       if (nft_flow_route(pkt, ct, &route, dir, priv->flowtable) < 0)
 189                 goto err_flow_route;
 190
 191         flow = flow_offload_alloc(ct);