This patch adds support for the decapsulation infrastructure, including
VLAN support for this.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/uapi/linux/netfilter/nf_tables.h | 16 +++++
net/netfilter/Kconfig | 6 ++
net/netfilter/Makefile | 1 +
net/netfilter/nft_encap.c | 119 +++++++++++++++++++++++++++++++
4 files changed, 142 insertions(+)
create mode 100644 net/netfilter/nft_encap.c
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 93326a544184..07aa6bba1548 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1629,6 +1629,22 @@ enum nft_xfrm_keys {
};
#define NFT_XFRM_KEY_MAX (__NFT_XFRM_KEY_MAX - 1)
+enum nft_encap_type {
+ NFT_ENCAP_VLAN = 0,
+};
+
+/**
+ * enum nft_decap_attributes - nf_tables decapsulation expression netlink attributes
+ *
+ * @NFTA_DECAP_TYPE: decapsulation type (NLA_U32)
+ */
+enum nft_decap_attributes {
+ NFTA_DECAP_UNSPEC,
+ NFTA_DECAP_TYPE,
+ __NFTA_DECAP_MAX,
+};
+#define NFTA_DECAP_MAX (__NFTA_DECAP_MAX - 1)
+
/**
* enum nft_trace_attributes - nf_tables trace netlink attributes
*
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 91efae88e8c2..573ea56aecfe 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -489,6 +489,12 @@ config NFT_CT
This option adds the "ct" expression that you can use to match
connection tracking information such as the flow state.
+config NFT_ENCAP
+ tristate "Netfilter nf_tables encapsulation/decapsulation module"
+ help
+ This option adds the encapsulation expression used to decapsulate
+ and to encapsulate packets through VLAN.
+
config NFT_FLOW_OFFLOAD
depends on NF_CONNTRACK && NF_FLOW_TABLE
tristate "Netfilter nf_tables hardware flow offload module"
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 5e9b2eb24349..66befd2ac11d 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_NFT_COMPAT) += nft_compat.o
obj-$(CONFIG_NFT_CONNLIMIT) += nft_connlimit.o
obj-$(CONFIG_NFT_NUMGEN) += nft_numgen.o
obj-$(CONFIG_NFT_CT) += nft_ct.o
+obj-$(CONFIG_NFT_ENCAP) += nft_encap.o
obj-$(CONFIG_NFT_FLOW_OFFLOAD) += nft_flow_offload.o
obj-$(CONFIG_NFT_LIMIT) += nft_limit.o
obj-$(CONFIG_NFT_NAT) += nft_nat.o
diff --git a/net/netfilter/nft_encap.c b/net/netfilter/nft_encap.c
new file mode 100644
index 000000000000..657a62e4c283
--- /dev/null
+++ b/net/netfilter/nft_encap.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_decap {
+ enum nft_encap_type type;
+};
+
+void nft_decap_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_decap *priv = nft_expr_priv(expr);
+ int err;
+
+ switch (priv->type) {
+ case NFT_ENCAP_VLAN:
+ err = skb_vlan_pop(pkt->skb);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ err = -1;
+ }
+
+ if (err < 0)
+ goto decap_error;
+
+ return;
+decap_error:
+ regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_decap_policy[NFTA_DECAP_MAX + 1] = {
+ [NFTA_DECAP_TYPE] = { .type = NLA_U32 },
+};
+
+static int nft_decap_init(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_decap *priv = nft_expr_priv(expr);
+
+ if (!tb[NFTA_DECAP_TYPE])
+ return -EINVAL;
+
+ priv->type = ntohl(nla_get_be32(tb[NFTA_DECAP_TYPE]));
+ switch (priv->type) {
+ case NFT_ENCAP_VLAN:
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static int nft_decap_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ const struct nft_decap *priv = nft_expr_priv(expr);
+
+ if (nla_put_be32(skb, NFTA_DECAP_TYPE, htonl(priv->type)))
+ goto nla_put_failure;
+
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static int nft_decap_validate(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nft_data **data)
+{
+ if (ctx->family != NFPROTO_NETDEV)
+ return -EOPNOTSUPP;
+
+ return nft_chain_validate_hooks(ctx->chain, 1 << NF_NETDEV_INGRESS);
+}
+
+static struct nft_expr_type nft_decap_type;
+static const struct nft_expr_ops nft_decap_ops = {
+ .type = &nft_decap_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_decap)),
+ .eval = nft_decap_eval,
+ .init = nft_decap_init,
+ .dump = nft_decap_dump,
+ .validate = nft_decap_validate,
+};
+
+static struct nft_expr_type nft_decap_type __read_mostly = {
+ .name = "decap",
+ .ops = &nft_decap_ops,
+ .policy = nft_decap_policy,
+ .maxattr = NFTA_DECAP_MAX,
+ .owner = THIS_MODULE,
+};
+
+static int __init nft_encap_netdev_module_init(void)
+{
+ return nft_register_expr(&nft_decap_type);
+}
+
+static void __exit nft_encap_netdev_module_exit(void)
+{
+ nft_unregister_expr(&nft_decap_type);
+}
+
+module_init(nft_encap_netdev_module_init);
+module_exit(nft_encap_netdev_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>");
+MODULE_ALIAS_NFT_AF_EXPR(5, "decap");
--
2.11.0
