This patch allows us to match on the tunnel metadata that is available
of the packet. We can use this to validate if the packet comes from/goes
to tunnel and the corresponding tunnel ID.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 15 +++++
net/netfilter/nft_tunnel.c | 112 ++++++++++++++++++++++++++++++-
2 files changed, 126 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 3ee1198eeac1..357862d948de 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1647,4 +1647,19 @@ enum nft_tunnel_key_attributes {
};
#define NFTA_TUNNEL_KEY_MAX (__NFTA_TUNNEL_KEY_MAX - 1)
+enum nft_tunnel_keys {
+ NFT_TUNNEL_PATH,
+ NFT_TUNNEL_ID,
+ __NFT_TUNNEL_MAX
+};
+#define NFT_TUNNEL_MAX (__NFT_TUNNEL_MAX - 1)
+
+enum nft_tunnel_attributes {
+ NFTA_TUNNEL_UNSPEC,
+ NFTA_TUNNEL_KEY,
+ NFTA_TUNNEL_DREG,
+ __NFTA_TUNNEL_MAX
+};
+#define NFTA_TUNNEL_MAX (__NFTA_TUNNEL_MAX - 1)
+
#endif /* _LINUX_NF_TABLES_H */
diff --git a/net/netfilter/nft_tunnel.c b/net/netfilter/nft_tunnel.c
index 715613d99c20..9332d7933dd5 100644
--- a/net/netfilter/nft_tunnel.c
+++ b/net/netfilter/nft_tunnel.c
@@ -12,6 +12,104 @@
#include <net/vxlan.h>
#include <net/erspan.h>
+struct nft_tunnel {
+ enum nft_tunnel_keys key:8;
+ enum nft_registers dreg:8;
+};
+
+static void nft_tunnel_get_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_tunnel *priv = nft_expr_priv(expr);
+ u32 *dest = ®s->data[priv->dreg];
+ struct ip_tunnel_info *tun_info;
+
+ tun_info = skb_tunnel_info(pkt->skb);
+
+ switch (priv->key) {
+ case NFT_TUNNEL_PATH:
+ nft_reg_store8(dest, !!tun_info);
+ break;
+ case NFT_TUNNEL_ID:
+ if (!tun_info) {
+ regs->verdict.code = NFT_BREAK;
+ return;
+ }
+ *dest = ntohl(tunnel_id_to_key32(tun_info->key.tun_id));
+ break;
+ default:
+ WARN_ON(1);
+ regs->verdict.code = NFT_BREAK;
+ }
+}
+
+static const struct nla_policy nft_tunnel_policy[NFTA_TUNNEL_MAX + 1] = {
+ [NFTA_TUNNEL_KEY] = { .type = NLA_U32 },
+ [NFTA_TUNNEL_DREG] = { .type = NLA_U32 },
+};
+
+static int nft_tunnel_get_init(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_tunnel *priv = nft_expr_priv(expr);
+ u32 len;
+
+ if (!tb[NFTA_TUNNEL_KEY] &&
+ !tb[NFTA_TUNNEL_DREG])
+ return -EINVAL;
+
+ priv->key = ntohl(nla_get_be32(tb[NFTA_TUNNEL_KEY]));
+ switch (priv->key) {
+ case NFT_TUNNEL_PATH:
+ len = sizeof(u8);
+ break;
+ case NFT_TUNNEL_ID:
+ len = sizeof(u32);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ priv->dreg = nft_parse_register(tb[NFTA_TUNNEL_DREG]);
+
+ return nft_validate_register_store(ctx, priv->dreg, NULL,
+ NFT_DATA_VALUE, len);
+}
+
+static int nft_tunnel_get_dump(struct sk_buff *skb,
+ const struct nft_expr *expr)
+{
+ const struct nft_tunnel *priv = nft_expr_priv(expr);
+
+ if (nla_put_be32(skb, NFTA_TUNNEL_KEY, htonl(priv->key)))
+ goto nla_put_failure;
+ if (nft_dump_register(skb, NFTA_TUNNEL_DREG, priv->dreg))
+ goto nla_put_failure;
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static struct nft_expr_type nft_tunnel_type;
+static const struct nft_expr_ops nft_tunnel_get_ops = {
+ .type = &nft_tunnel_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_tunnel)),
+ .eval = nft_tunnel_get_eval,
+ .init = nft_tunnel_get_init,
+ .dump = nft_tunnel_get_dump,
+};
+
+static struct nft_expr_type nft_tunnel_type __read_mostly = {
+ .name = "tunnel",
+ .ops = &nft_tunnel_get_ops,
+ .policy = nft_tunnel_policy,
+ .maxattr = NFTA_TUNNEL_MAX,
+ .owner = THIS_MODULE,
+};
+
struct nft_tunnel_opts {
union {
struct vxlan_metadata vxlan;
@@ -442,12 +540,23 @@ static struct nft_object_type nft_tunnel_obj_type __read_mostly = {
static int __init nft_tunnel_module_init(void)
{
- return nft_register_obj(&nft_tunnel_obj_type);
+ int err;
+
+ err = nft_register_expr(&nft_tunnel_type);
+ if (err < 0)
+ return err;
+
+ err = nft_register_obj(&nft_tunnel_obj_type);
+ if (err < 0)
+ nft_unregister_expr(&nft_tunnel_type);
+
+ return err;
}
static void __exit nft_tunnel_module_exit(void)
{
nft_unregister_obj(&nft_tunnel_obj_type);
+ nft_unregister_expr(&nft_tunnel_type);
}
module_init(nft_tunnel_module_init);
@@ -455,4 +564,5 @@ module_exit(nft_tunnel_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>");
+MODULE_ALIAS_NFT_EXPR("tunnel");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_TUNNEL);
--
2.11.0
--
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