This patch adds encapsulation support through the encapsulation object,
that specifies the encapsulation policy.

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 include/uapi/linux/netfilter/nf_tables.h |  40 +++++-
 net/netfilter/nft_encap.c                | 224 ++++++++++++++++++++++++++++++-
 2 files changed, 262 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/netfilter/nf_tables.h 
b/include/uapi/linux/netfilter/nf_tables.h
index 25e26340a0ba..e5997a13ba71 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1484,7 +1484,8 @@ enum nft_ct_expectation_attributes {
 #define NFT_OBJECT_SECMARK     8
 #define NFT_OBJECT_CT_EXPECT   9
 #define NFT_OBJECT_SYNPROXY    10
-#define __NFT_OBJECT_MAX       11
+#define NFT_OBJECT_ENCAP       11
+#define __NFT_OBJECT_MAX       12
 #define NFT_OBJECT_MAX         (__NFT_OBJECT_MAX - 1)
 
 /**
@@ -1629,6 +1630,43 @@ enum nft_encap_type {
        NFT_ENCAP_VLAN  = 0,
 };
 
+enum nft_encap_op {
+       NFT_ENCAP_ADD   = 0,
+       NFT_ENCAP_UPDATE,
+};
+
+/**
+ * enum nft_encap_vlan_attributes - nf_tables VLAN encapsulation expression 
netlink attributes
+ *
+ * @NFTA_ENCAP_VLAN_ID: VLAN id (NLA_U16)
+ * @NFTA_ENCAP_VLAN_PROTO: VLAN protocol (NLA_U16)
+ * @NFTA_ENCAP_VLAN_PRIO: VLAN priority (NLA_U8)
+ */
+enum nft_encap_vlan_attributes {
+       NFTA_ENCAP_VLAN_UNSPEC,
+       NFTA_ENCAP_VLAN_ID,
+       NFTA_ENCAP_VLAN_PROTO,
+       NFTA_ENCAP_VLAN_PRIO,
+       __NFTA_ENCAP_VLAN_MAX
+};
+#define NFTA_ENCAP_VLAN_MAX    (__NFTA_ENCAP_VLAN_MAX - 1)
+
+/**
+ * enum nft_encap_attributes - nf_tables encapsulation expression netlink 
attributes
+ *
+ * @NFTA_ENCAP_TYPE: encapsulation type (NLA_U32)
+ * @NFTA_ENCAP_OP: encapsulation operation (NLA_U32)
+ * @NFTA_ENCAP_DATA: encapsulation data (NLA_NESTED)
+ */
+enum nft_encap_attributes {
+       NFTA_ENCAP_UNSPEC,
+       NFTA_ENCAP_TYPE,
+       NFTA_ENCAP_OP,
+       NFTA_ENCAP_DATA,
+       __NFTA_ENCAP_MAX
+};
+#define NFTA_ENCAP_MAX (__NFTA_ENCAP_MAX - 1)
+
 /**
  * enum nft_decap_attributes - nf_tables decapsulation expression netlink 
attributes
  *
diff --git a/net/netfilter/nft_encap.c b/net/netfilter/nft_encap.c
index 657a62e4c283..13643b3daf85 100644
--- a/net/netfilter/nft_encap.c
+++ b/net/netfilter/nft_encap.c
@@ -2,6 +2,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/if_vlan.h>
 #include <linux/netlink.h>
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
@@ -101,14 +102,235 @@ static struct nft_expr_type nft_decap_type __read_mostly 
= {
        .owner          = THIS_MODULE,
 };
 
+struct nft_encap {
+       enum nft_encap_type     type;
+       enum nft_encap_op       op;
+
+       union {
+               struct {
+                       __u16   id;
+                       __be16  proto;
+                       __u8    prio;
+               } vlan;
+       };
+};
+
+static u16 nft_encap_vlan_tci(struct nft_encap *priv)
+{
+       return priv->vlan.id | (priv->vlan.prio << VLAN_PRIO_SHIFT);
+}
+
+static int nft_encap_vlan_eval(struct nft_encap *priv,
+                              struct nft_regs *regs,
+                              const struct nft_pktinfo *pkt)
+{
+       struct sk_buff *skb = pkt->skb;
+       int err;
+       u16 tci;
+
+       switch (priv->op) {
+       case NFT_ENCAP_ADD:
+               err = skb_vlan_push(skb, priv->vlan.proto,
+                                   nft_encap_vlan_tci(priv));
+               if (err)
+                       return err;
+               break;
+       case NFT_ENCAP_UPDATE:
+               if (!skb_vlan_tagged(skb))
+                       return -1;
+
+               err = 0;
+               if (skb_vlan_tag_present(skb)) {
+                       tci = skb_vlan_tag_get(skb);
+                       __vlan_hwaccel_clear_tag(skb);
+               } else {
+                       err = __skb_vlan_pop(skb, &tci);
+               }
+               if (err)
+                       return err;
+
+               tci = (tci & ~VLAN_VID_MASK) | priv->vlan.id;
+               if (priv->vlan.prio) {
+                       tci &= ~VLAN_PRIO_MASK;
+                       tci |= priv->vlan.prio << VLAN_PRIO_SHIFT;
+               }
+
+               __vlan_hwaccel_put_tag(skb, priv->vlan.proto, tci);
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+static void nft_encap_obj_eval(struct nft_object *obj,
+                              struct nft_regs *regs,
+                              const struct nft_pktinfo *pkt)
+{
+       struct nft_encap *priv = nft_obj_data(obj);
+       int err;
+
+       switch (priv->type) {
+       case NFT_ENCAP_VLAN:
+               err = nft_encap_vlan_eval(priv, regs, pkt);
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               err = -1;
+       }
+
+       if (err < 0)
+               regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_encap_vlan_policy[NFTA_ENCAP_VLAN_MAX + 1] 
= {
+       [NFTA_ENCAP_VLAN_ID]    = { .type = NLA_U16 },
+       [NFTA_ENCAP_VLAN_PROTO] = { .type = NLA_U16 },
+       [NFTA_ENCAP_VLAN_PRIO]  = { .type = NLA_U8 },
+};
+
+static int nft_encap_vlan_parse(const struct nlattr *attr,
+                               struct nft_encap *priv)
+{
+       struct nlattr *tb[NFTA_ENCAP_VLAN_MAX + 1];
+       int err;
+
+       err = nla_parse_nested_deprecated(tb, NFTA_ENCAP_VLAN_MAX, attr,
+                                         nft_encap_vlan_policy, NULL);
+       if (err < 0)
+               return err;
+
+       if (!tb[NFTA_ENCAP_VLAN_PRIO] ||
+           !tb[NFTA_ENCAP_VLAN_PROTO] ||
+           !tb[NFTA_ENCAP_VLAN_ID])
+               return -EINVAL;
+
+       priv->vlan.id = ntohs(nla_get_be16(tb[NFTA_ENCAP_VLAN_ID]));
+       priv->vlan.proto = nla_get_be16(tb[NFTA_ENCAP_VLAN_PROTO]);
+       priv->vlan.prio = nla_get_u8(tb[NFTA_ENCAP_VLAN_PRIO]);
+
+       return 0;
+}
+
+static int nft_encap_obj_init(const struct nft_ctx *ctx,
+                             const struct nlattr * const tb[],
+                             struct nft_object *obj)
+{
+       struct nft_encap *priv = nft_obj_data(obj);
+       int err = 0;
+
+       if (!tb[NFTA_ENCAP_TYPE] ||
+           !tb[NFTA_ENCAP_OP])
+               return -EINVAL;
+
+       priv->type = ntohl(nla_get_be32(tb[NFTA_ENCAP_TYPE]));
+       priv->op = ntohl(nla_get_be32(tb[NFTA_ENCAP_OP]));
+
+       switch (priv->type) {
+       case NFT_ENCAP_VLAN:
+               if (priv->op != NFT_ENCAP_ADD &&
+                   priv->op != NFT_ENCAP_UPDATE)
+                       return -EOPNOTSUPP;
+
+               err = nft_encap_vlan_parse(tb[NFTA_ENCAP_DATA], priv);
+               break;
+       default:
+               return -EOPNOTSUPP;
+       }
+
+       return err;
+}
+
+static int nft_encap_type_dump(struct sk_buff *skb, struct nft_encap *priv)
+{
+       struct nlattr *nest;
+
+       nest = nla_nest_start_noflag(skb, NFTA_ENCAP_DATA);
+       if (!nest)
+               goto nla_put_failure;
+
+       switch (priv->type) {
+       case NFT_ENCAP_VLAN:
+               if (nla_put_be16(skb, NFTA_ENCAP_VLAN_ID, htons(priv->vlan.id)) 
||
+                   nla_put_be16(skb, NFTA_ENCAP_VLAN_PROTO, priv->vlan.proto) 
||
+                   nla_put_u8(skb, NFTA_ENCAP_VLAN_PRIO, priv->vlan.prio))
+                       goto nla_put_failure;
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               break;
+       }
+       nla_nest_end(skb, nest);
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static int nft_encap_obj_dump(struct sk_buff *skb, struct nft_object *obj,
+                             bool reset)
+{
+       struct nft_encap *priv = nft_obj_data(obj);
+
+       if (nla_put_be32(skb, NFTA_ENCAP_TYPE, htonl(priv->type)) ||
+           nla_put_be32(skb, NFTA_ENCAP_OP, htonl(priv->op)) ||
+           nft_encap_type_dump(skb, priv))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
+static const struct nla_policy nft_encap_policy[NFTA_ENCAP_MAX + 1] = {
+       [NFTA_ENCAP_TYPE]       = { .type = NLA_U32 },
+       [NFTA_ENCAP_OP]         = { .type = NLA_U32 },
+       [NFTA_ENCAP_DATA]       = { .type = NLA_NESTED },
+};
+
+static struct nft_object_type nft_encap_obj_type;
+static const struct nft_object_ops nft_encap_obj_ops = {
+       .type           = &nft_encap_obj_type,
+       .size           = sizeof(struct nft_encap),
+       .eval           = nft_encap_obj_eval,
+       .init           = nft_encap_obj_init,
+       .dump           = nft_encap_obj_dump,
+};
+
+static struct nft_object_type nft_encap_obj_type __read_mostly = {
+       .type           = NFT_OBJECT_ENCAP,
+       .ops            = &nft_encap_obj_ops,
+       .maxattr        = NFTA_ENCAP_MAX,
+       .policy         = nft_encap_policy,
+       .owner          = THIS_MODULE,
+};
+
 static int __init nft_encap_netdev_module_init(void)
 {
-       return nft_register_expr(&nft_decap_type);
+       int err;
+
+       err = nft_register_obj(&nft_encap_obj_type);
+       if (err < 0)
+               return err;
+
+       err = nft_register_expr(&nft_decap_type);
+       if (err < 0)
+               goto err_unregister;
+
+       return 0;
+
+err_unregister:
+       nft_unregister_obj(&nft_encap_obj_type);
+       return err;
 }
 
 static void __exit nft_encap_netdev_module_exit(void)
 {
        nft_unregister_expr(&nft_decap_type);
+       nft_unregister_obj(&nft_encap_obj_type);
 }
 
 module_init(nft_encap_netdev_module_init);
-- 
2.11.0

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