target/linux/generic/backport-5.4/080-wireguard-0109-net-ip_tunnel-add-header_ops-for-layer-3-devices.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: "Jason A. Donenfeld" <Jason@zx2c4.com>
   3 Date: Mon, 29 Jun 2020 19:06:18 -0600
   4 Subject: [PATCH] net: ip_tunnel: add header_ops for layer 3 devices
   5
   6 commit 2606aff916854b61234bf85001be9777bab2d5f8 upstream.
   7
   8 Some devices that take straight up layer 3 packets benefit from having a
   9 shared header_ops so that AF_PACKET sockets can inject packets that are
  10 recognized. This shared infrastructure will be used by other drivers
  11 that currently can't inject packets using AF_PACKET. It also exposes the
  12 parser function, as it is useful in standalone form too.
  13
  14 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  15 Acked-by: Willem de Bruijn <willemb@google.com>
  16 Signed-off-by: David S. Miller <davem@davemloft.net>
  17 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  18 ---
  19  include/net/ip_tunnels.h  |  3 +++
  20  net/ipv4/ip_tunnel_core.c | 18 ++++++++++++++++++
  21  2 files changed, 21 insertions(+)
  22
  23 --- a/include/net/ip_tunnels.h
  24 +++ b/include/net/ip_tunnels.h
  25 @@ -289,6 +289,9 @@ int ip_tunnel_newlink(struct net_device
  26                       struct ip_tunnel_parm *p, __u32 fwmark);
  27  void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
  28
  29 +extern const struct header_ops ip_tunnel_header_ops;
  30 +__be16 ip_tunnel_parse_protocol(const struct sk_buff *skb);
  31 +
  32  struct ip_tunnel_encap_ops {
  33         size_t (*encap_hlen)(struct ip_tunnel_encap *e);
  34         int (*build_header)(struct sk_buff *skb, struct ip_tunnel_encap *e,
  35 --- a/net/ipv4/ip_tunnel_core.c
  36 +++ b/net/ipv4/ip_tunnel_core.c
  37 @@ -446,3 +446,21 @@ void ip_tunnel_unneed_metadata(void)
  38         static_branch_dec(&ip_tunnel_metadata_cnt);
  39  }
  40  EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);
  41 +
  42 +/* Returns either the correct skb->protocol value, or 0 if invalid. */
  43 +__be16 ip_tunnel_parse_protocol(const struct sk_buff *skb)
  44 +{
  45 +       if (skb_network_header(skb) >= skb->head &&
  46 +           (skb_network_header(skb) + sizeof(struct iphdr)) <= skb_tail_pointer(skb) &&
  47 +           ip_hdr(skb)->version == 4)
  48 +               return htons(ETH_P_IP);
  49 +       if (skb_network_header(skb) >= skb->head &&
  50 +           (skb_network_header(skb) + sizeof(struct ipv6hdr)) <= skb_tail_pointer(skb) &&
  51 +           ipv6_hdr(skb)->version == 6)
  52 +               return htons(ETH_P_IPV6);
  53 +       return 0;
  54 +}
  55 +EXPORT_SYMBOL(ip_tunnel_parse_protocol);
  56 +
  57 +const struct header_ops ip_tunnel_header_ops = { .parse_protocol = ip_tunnel_parse_protocol };
  58 +EXPORT_SYMBOL(ip_tunnel_header_ops);